fs/btrfs/volumes.c

   1 /*
   2  * Copyright (C) 2007 Oracle.  All rights reserved.
   3  *
   4  * This program is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU General Public
   6  * License v2 as published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  11  * General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public
  14  * License along with this program; if not, write to the
  15  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  16  * Boston, MA 021110-1307, USA.
  17  */
  18 #include <linux/sched.h>
  19 #include <linux/bio.h>
  20 #include <linux/slab.h>
  21 #include <linux/buffer_head.h>
  22 #include <linux/blkdev.h>
  23 #include <linux/random.h>
  24 #include <linux/iocontext.h>
  25 #include <linux/capability.h>
  26 #include <linux/ratelimit.h>
  27 #include <linux/kthread.h>
  28 #include <linux/raid/pq.h>
  29 #include <linux/semaphore.h>
  30 #include <asm/div64.h>
  31 #include "ctree.h"
  32 #include "extent_map.h"
  33 #include "disk-io.h"
  34 #include "transaction.h"
  35 #include "print-tree.h"
  36 #include "volumes.h"
  37 #include "raid56.h"
  38 #include "async-thread.h"
  39 #include "check-integrity.h"
  40 #include "rcu-string.h"
  41 #include "math.h"
  42 #include "dev-replace.h"
  43 #include "sysfs.h"
  44
  45 const struct btrfs_raid_attr btrfs_raid_array[BTRFS_NR_RAID_TYPES] = {
  46         [BTRFS_RAID_RAID10] = {
  47                 .sub_stripes    = 2,
  48                 .dev_stripes    = 1,
  49                 .devs_max       = 0,    /* 0 == as many as possible */
  50                 .devs_min       = 4,
  51                 .tolerated_failures = 1,
  52                 .devs_increment = 2,
  53                 .ncopies        = 2,
  54         },
  55         [BTRFS_RAID_RAID1] = {
  56                 .sub_stripes    = 1,
  57                 .dev_stripes    = 1,
  58                 .devs_max       = 2,
  59                 .devs_min       = 2,
  60                 .tolerated_failures = 1,
  61                 .devs_increment = 2,
  62                 .ncopies        = 2,
  63         },
  64         [BTRFS_RAID_DUP] = {
  65                 .sub_stripes    = 1,
  66                 .dev_stripes    = 2,
  67                 .devs_max       = 1,
  68                 .devs_min       = 1,
  69                 .tolerated_failures = 0,
  70                 .devs_increment = 1,
  71                 .ncopies        = 2,
  72         },
  73         [BTRFS_RAID_RAID0] = {
  74                 .sub_stripes    = 1,
  75                 .dev_stripes    = 1,
  76                 .devs_max       = 0,
  77                 .devs_min       = 2,
  78                 .tolerated_failures = 0,
  79                 .devs_increment = 1,
  80                 .ncopies        = 1,
  81         },
  82         [BTRFS_RAID_SINGLE] = {
  83                 .sub_stripes    = 1,
  84                 .dev_stripes    = 1,
  85                 .devs_max       = 1,
  86                 .devs_min       = 1,
  87                 .tolerated_failures = 0,
  88                 .devs_increment = 1,
  89                 .ncopies        = 1,
  90         },
  91         [BTRFS_RAID_RAID5] = {
  92                 .sub_stripes    = 1,
  93                 .dev_stripes    = 1,
  94                 .devs_max       = 0,
  95                 .devs_min       = 2,
  96                 .tolerated_failures = 1,
  97                 .devs_increment = 1,
  98                 .ncopies        = 2,
  99         },
 100         [BTRFS_RAID_RAID6] = {
 101                 .sub_stripes    = 1,
 102                 .dev_stripes    = 1,
 103                 .devs_max       = 0,
 104                 .devs_min       = 3,
 105                 .tolerated_failures = 2,
 106                 .devs_increment = 1,
 107                 .ncopies        = 3,
 108         },
 109 };
 110
 111 const u64 const btrfs_raid_group[BTRFS_NR_RAID_TYPES] = {
 112         [BTRFS_RAID_RAID10] = BTRFS_BLOCK_GROUP_RAID10,
 113         [BTRFS_RAID_RAID1]  = BTRFS_BLOCK_GROUP_RAID1,
 114         [BTRFS_RAID_DUP]    = BTRFS_BLOCK_GROUP_DUP,
 115         [BTRFS_RAID_RAID0]  = BTRFS_BLOCK_GROUP_RAID0,
 116         [BTRFS_RAID_SINGLE] = 0,
 117         [BTRFS_RAID_RAID5]  = BTRFS_BLOCK_GROUP_RAID5,
 118         [BTRFS_RAID_RAID6]  = BTRFS_BLOCK_GROUP_RAID6,
 119 };
 120
 121 static int init_first_rw_device(struct btrfs_trans_handle *trans,
 122                                 struct btrfs_root *root,
 123                                 struct btrfs_device *device);
 124 static int btrfs_relocate_sys_chunks(struct btrfs_root *root);
 125 static void __btrfs_reset_dev_stats(struct btrfs_device *dev);
 126 static void btrfs_dev_stat_print_on_error(struct btrfs_device *dev);
 127 static void btrfs_dev_stat_print_on_load(struct btrfs_device *device);
 128
 129 DEFINE_MUTEX(uuid_mutex);
 130 static LIST_HEAD(fs_uuids);
 131 struct list_head *btrfs_get_fs_uuids(void)
 132 {
 133         return &fs_uuids;
 134 }
 135
 136 static struct btrfs_fs_devices *__alloc_fs_devices(void)
 137 {
 138         struct btrfs_fs_devices *fs_devs;
 139
 140         fs_devs = kzalloc(sizeof(*fs_devs), GFP_NOFS);
 141         if (!fs_devs)
 142                 return ERR_PTR(-ENOMEM);
 143
 144         mutex_init(&fs_devs->device_list_mutex);
 145
 146         INIT_LIST_HEAD(&fs_devs->devices);
 147         INIT_LIST_HEAD(&fs_devs->resized_devices);
 148         INIT_LIST_HEAD(&fs_devs->alloc_list);
 149         INIT_LIST_HEAD(&fs_devs->list);
 150
 151         return fs_devs;
 152 }
 153
 154 /**
 155  * alloc_fs_devices - allocate struct btrfs_fs_devices
 156  * @fsid:       a pointer to UUID for this FS.  If NULL a new UUID is
 157  *              generated.
 158  *
 159  * Return: a pointer to a new &struct btrfs_fs_devices on success;
 160  * ERR_PTR() on error.  Returned struct is not linked onto any lists and
 161  * can be destroyed with kfree() right away.
 162  */
 163 static struct btrfs_fs_devices *alloc_fs_devices(const u8 *fsid)
 164 {
 165         struct btrfs_fs_devices *fs_devs;
 166
 167         fs_devs = __alloc_fs_devices();
 168         if (IS_ERR(fs_devs))
 169                 return fs_devs;
 170
 171         if (fsid)
 172                 memcpy(fs_devs->fsid, fsid, BTRFS_FSID_SIZE);
 173         else
 174                 generate_random_uuid(fs_devs->fsid);
 175
 176         return fs_devs;
 177 }
 178
 179 static void free_fs_devices(struct btrfs_fs_devices *fs_devices)
 180 {
 181         struct btrfs_device *device;
 182         WARN_ON(fs_devices->opened);
 183         while (!list_empty(&fs_devices->devices)) {
 184                 device = list_entry(fs_devices->devices.next,
 185                                     struct btrfs_device, dev_list);
 186                 list_del(&device->dev_list);
 187                 rcu_string_free(device->name);
 188                 kfree(device);
 189         }
 190         kfree(fs_devices);
 191 }
 192
 193 static void btrfs_kobject_uevent(struct block_device *bdev,
 194                                  enum kobject_action action)
 195 {
 196         int ret;
 197
 198         ret = kobject_uevent(&disk_to_dev(bdev->bd_disk)->kobj, action);
 199         if (ret)
 200                 pr_warn("BTRFS: Sending event '%d' to kobject: '%s' (%p): failed\n",
 201                         action,
 202                         kobject_name(&disk_to_dev(bdev->bd_disk)->kobj),
 203                         &disk_to_dev(bdev->bd_disk)->kobj);
 204 }
 205
 206 void btrfs_cleanup_fs_uuids(void)
 207 {
 208         struct btrfs_fs_devices *fs_devices;
 209
 210         while (!list_empty(&fs_uuids)) {
 211                 fs_devices = list_entry(fs_uuids.next,
 212                                         struct btrfs_fs_devices, list);
 213                 list_del(&fs_devices->list);
 214                 free_fs_devices(fs_devices);
 215         }
 216 }
 217
 218 static struct btrfs_device *__alloc_device(void)
 219 {
 220         struct btrfs_device *dev;
 221
 222         dev = kzalloc(sizeof(*dev), GFP_NOFS);
 223         if (!dev)
 224                 return ERR_PTR(-ENOMEM);
 225
 226         INIT_LIST_HEAD(&dev->dev_list);
 227         INIT_LIST_HEAD(&dev->dev_alloc_list);
 228         INIT_LIST_HEAD(&dev->resized_list);
 229
 230         spin_lock_init(&dev->io_lock);
 231
 232         spin_lock_init(&dev->reada_lock);
 233         atomic_set(&dev->reada_in_flight, 0);
 234         atomic_set(&dev->dev_stats_ccnt, 0);
 235         INIT_RADIX_TREE(&dev->reada_zones, GFP_NOFS & ~__GFP_DIRECT_RECLAIM);
 236         INIT_RADIX_TREE(&dev->reada_extents, GFP_NOFS & ~__GFP_DIRECT_RECLAIM);
 237
 238         return dev;
 239 }
 240
 241 static noinline struct btrfs_device *__find_device(struct list_head *head,
 242                                                    u64 devid, u8 *uuid)
 243 {
 244         struct btrfs_device *dev;
 245
 246         list_for_each_entry(dev, head, dev_list) {
 247                 if (dev->devid == devid &&
 248                     (!uuid || !memcmp(dev->uuid, uuid, BTRFS_UUID_SIZE))) {
 249                         return dev;
 250                 }
 251         }
 252         return NULL;
 253 }
 254
 255 static noinline struct btrfs_fs_devices *find_fsid(u8 *fsid)
 256 {
 257         struct btrfs_fs_devices *fs_devices;
 258
 259         list_for_each_entry(fs_devices, &fs_uuids, list) {
 260                 if (memcmp(fsid, fs_devices->fsid, BTRFS_FSID_SIZE) == 0)
 261                         return fs_devices;
 262         }
 263         return NULL;
 264 }
 265
 266 static int
 267 btrfs_get_bdev_and_sb(const char *device_path, fmode_t flags, void *holder,
 268                       int flush, struct block_device **bdev,
 269                       struct buffer_head **bh)
 270 {
 271         int ret;
 272
 273         *bdev = blkdev_get_by_path(device_path, flags, holder);
 274
 275         if (IS_ERR(*bdev)) {
 276                 ret = PTR_ERR(*bdev);
 277                 goto error;
 278         }
 279
 280         if (flush)
 281                 filemap_write_and_wait((*bdev)->bd_inode->i_mapping);
 282         ret = set_blocksize(*bdev, 4096);
 283         if (ret) {
 284                 blkdev_put(*bdev, flags);
 285                 goto error;
 286         }
 287         invalidate_bdev(*bdev);
 288         *bh = btrfs_read_dev_super(*bdev);
 289         if (IS_ERR(*bh)) {
 290                 ret = PTR_ERR(*bh);
 291                 blkdev_put(*bdev, flags);
 292                 goto error;
 293         }
 294
 295         return 0;
 296
 297 error:
 298         *bdev = NULL;
 299         *bh = NULL;
 300         return ret;
 301 }
 302
 303 static void requeue_list(struct btrfs_pending_bios *pending_bios,
 304                         struct bio *head, struct bio *tail)
 305 {
 306
 307         struct bio *old_head;
 308
 309         old_head = pending_bios->head;
 310         pending_bios->head = head;
 311         if (pending_bios->tail)
 312                 tail->bi_next = old_head;
 313         else
 314                 pending_bios->tail = tail;
 315 }
 316
 317 /*
 318  * we try to collect pending bios for a device so we don't get a large
 319  * number of procs sending bios down to the same device.  This greatly
 320  * improves the schedulers ability to collect and merge the bios.
 321  *
 322  * But, it also turns into a long list of bios to process and that is sure
 323  * to eventually make the worker thread block.  The solution here is to
 324  * make some progress and then put this work struct back at the end of
 325  * the list if the block device is congested.  This way, multiple devices
 326  * can make progress from a single worker thread.
 327  */
 328 static noinline void run_scheduled_bios(struct btrfs_device *device)
 329 {
 330         struct bio *pending;
 331         struct backing_dev_info *bdi;
 332         struct btrfs_fs_info *fs_info;
 333         struct btrfs_pending_bios *pending_bios;
 334         struct bio *tail;
 335         struct bio *cur;
 336         int again = 0;
 337         unsigned long num_run;
 338         unsigned long batch_run = 0;
 339         unsigned long limit;
 340         unsigned long last_waited = 0;
 341         int force_reg = 0;
 342         int sync_pending = 0;
 343         struct blk_plug plug;
 344
 345         /*
 346          * this function runs all the bios we've collected for
 347          * a particular device.  We don't want to wander off to
 348          * another device without first sending all of these down.
 349          * So, setup a plug here and finish it off before we return
 350          */
 351         blk_start_plug(&plug);
 352
 353         bdi = blk_get_backing_dev_info(device->bdev);
 354         fs_info = device->dev_root->fs_info;
 355         limit = btrfs_async_submit_limit(fs_info);
 356         limit = limit * 2 / 3;
 357
 358 loop:
 359         spin_lock(&device->io_lock);
 360
 361 loop_lock:
 362         num_run = 0;
 363
 364         /* take all the bios off the list at once and process them
 365          * later on (without the lock held).  But, remember the
 366          * tail and other pointers so the bios can be properly reinserted
 367          * into the list if we hit congestion
 368          */
 369         if (!force_reg && device->pending_sync_bios.head) {
 370                 pending_bios = &device->pending_sync_bios;
 371                 force_reg = 1;
 372         } else {
 373                 pending_bios = &device->pending_bios;
 374                 force_reg = 0;
 375         }
 376
 377         pending = pending_bios->head;
 378         tail = pending_bios->tail;
 379         WARN_ON(pending && !tail);
 380
 381         /*
 382          * if pending was null this time around, no bios need processing
 383          * at all and we can stop.  Otherwise it'll loop back up again
 384          * and do an additional check so no bios are missed.
 385          *
 386          * device->running_pending is used to synchronize with the
 387          * schedule_bio code.
 388          */
 389         if (device->pending_sync_bios.head == NULL &&
 390             device->pending_bios.head == NULL) {
 391                 again = 0;
 392                 device->running_pending = 0;
 393         } else {
 394                 again = 1;
 395                 device->running_pending = 1;
 396         }
 397
 398         pending_bios->head = NULL;
 399         pending_bios->tail = NULL;
 400
 401         spin_unlock(&device->io_lock);
 402
 403         while (pending) {
 404
 405                 rmb();
 406                 /* we want to work on both lists, but do more bios on the
 407                  * sync list than the regular list
 408                  */
 409                 if ((num_run > 32 &&
 410                     pending_bios != &device->pending_sync_bios &&
 411                     device->pending_sync_bios.head) ||
 412                    (num_run > 64 && pending_bios == &device->pending_sync_bios &&
 413                     device->pending_bios.head)) {
 414                         spin_lock(&device->io_lock);
 415                         requeue_list(pending_bios, pending, tail);
 416                         goto loop_lock;
 417                 }
 418
 419                 cur = pending;
 420                 pending = pending->bi_next;
 421                 cur->bi_next = NULL;
 422
 423                 /*
 424                  * atomic_dec_return implies a barrier for waitqueue_active
 425                  */
 426                 if (atomic_dec_return(&fs_info->nr_async_bios) < limit &&
 427                     waitqueue_active(&fs_info->async_submit_wait))
 428                         wake_up(&fs_info->async_submit_wait);
 429
 430                 BUG_ON(atomic_read(&cur->__bi_cnt) == 0);
 431
 432                 /*
 433                  * if we're doing the sync list, record that our
 434                  * plug has some sync requests on it
 435                  *
 436                  * If we're doing the regular list and there are
 437                  * sync requests sitting around, unplug before
 438                  * we add more
 439                  */
 440                 if (pending_bios == &device->pending_sync_bios) {
 441                         sync_pending = 1;
 442                 } else if (sync_pending) {
 443                         blk_finish_plug(&plug);
 444                         blk_start_plug(&plug);
 445                         sync_pending = 0;
 446                 }
 447
 448                 btrfsic_submit_bio(cur->bi_rw, cur);
 449                 num_run++;
 450                 batch_run++;
 451
 452                 cond_resched();
 453
 454                 /*
 455                  * we made progress, there is more work to do and the bdi
 456                  * is now congested.  Back off and let other work structs
 457                  * run instead
 458                  */
 459                 if (pending && bdi_write_congested(bdi) && batch_run > 8 &&
 460                     fs_info->fs_devices->open_devices > 1) {
 461                         struct io_context *ioc;
 462
 463                         ioc = current->io_context;
 464
 465                         /*
 466                          * the main goal here is that we don't want to
 467                          * block if we're going to be able to submit
 468                          * more requests without blocking.
 469                          *
 470                          * This code does two great things, it pokes into
 471                          * the elevator code from a filesystem _and_
 472                          * it makes assumptions about how batching works.
 473                          */
 474                         if (ioc && ioc->nr_batch_requests > 0 &&
 475                             time_before(jiffies, ioc->last_waited + HZ/50UL) &&
 476                             (last_waited == 0 ||
 477                              ioc->last_waited == last_waited)) {
 478                                 /*
 479                                  * we want to go through our batch of
 480                                  * requests and stop.  So, we copy out
 481                                  * the ioc->last_waited time and test
 482                                  * against it before looping
 483                                  */
 484                                 last_waited = ioc->last_waited;
 485                                 cond_resched();
 486                                 continue;
 487                         }
 488                         spin_lock(&device->io_lock);
 489                         requeue_list(pending_bios, pending, tail);
 490                         device->running_pending = 1;
 491
 492                         spin_unlock(&device->io_lock);
 493                         btrfs_queue_work(fs_info->submit_workers,
 494                                          &device->work);
 495                         goto done;
 496                 }
 497                 /* unplug every 64 requests just for good measure */
 498                 if (batch_run % 64 == 0) {
 499                         blk_finish_plug(&plug);
 500                         blk_start_plug(&plug);
 501                         sync_pending = 0;
 502                 }
 503         }
 504
 505         cond_resched();
 506         if (again)
 507                 goto loop;
 508
 509         spin_lock(&device->io_lock);
 510         if (device->pending_bios.head || device->pending_sync_bios.head)
 511                 goto loop_lock;
 512         spin_unlock(&device->io_lock);
 513
 514 done:
 515         blk_finish_plug(&plug);
 516 }
 517
 518 static void pending_bios_fn(struct btrfs_work *work)
 519 {
 520         struct btrfs_device *device;
 521
 522         device = container_of(work, struct btrfs_device, work);
 523         run_scheduled_bios(device);
 524 }
 525
 526
 527 void btrfs_free_stale_device(struct btrfs_device *cur_dev)
 528 {
 529         struct btrfs_fs_devices *fs_devs;
 530         struct btrfs_device *dev;
 531
 532         if (!cur_dev->name)
 533                 return;
 534
 535         list_for_each_entry(fs_devs, &fs_uuids, list) {
 536                 int del = 1;
 537
 538                 if (fs_devs->opened)
 539                         continue;
 540                 if (fs_devs->seeding)
 541                         continue;
 542
 543                 list_for_each_entry(dev, &fs_devs->devices, dev_list) {
 544
 545                         if (dev == cur_dev)
 546                                 continue;
 547                         if (!dev->name)
 548                                 continue;
 549
 550                         /*
 551                          * Todo: This won't be enough. What if the same device
 552                          * comes back (with new uuid and) with its mapper path?
 553                          * But for now, this does help as mostly an admin will
 554                          * either use mapper or non mapper path throughout.
 555                          */
 556                         rcu_read_lock();
 557                         del = strcmp(rcu_str_deref(dev->name),
 558                                                 rcu_str_deref(cur_dev->name));
 559                         rcu_read_unlock();
 560                         if (!del)
 561                                 break;
 562                 }
 563
 564                 if (!del) {
 565                         /* delete the stale device */
 566                         if (fs_devs->num_devices == 1) {
 567                                 btrfs_sysfs_remove_fsid(fs_devs);
 568                                 list_del(&fs_devs->list);
 569                                 free_fs_devices(fs_devs);
 570                         } else {
 571                                 fs_devs->num_devices--;
 572                                 list_del(&dev->dev_list);
 573                                 rcu_string_free(dev->name);
 574                                 kfree(dev);
 575                         }
 576                         break;
 577                 }
 578         }
 579 }
 580
 581 /*
 582  * Add new device to list of registered devices
 583  *
 584  * Returns:
 585  * 1   - first time device is seen
 586  * 0   - device already known
 587  * < 0 - error
 588  */
 589 static noinline int device_list_add(const char *path,
 590                            struct btrfs_super_block *disk_super,
 591                            u64 devid, struct btrfs_fs_devices **fs_devices_ret)
 592 {
 593         struct btrfs_device *device;
 594         struct btrfs_fs_devices *fs_devices;
 595         struct rcu_string *name;
 596         int ret = 0;
 597         u64 found_transid = btrfs_super_generation(disk_super);
 598
 599         fs_devices = find_fsid(disk_super->fsid);
 600         if (!fs_devices) {
 601                 fs_devices = alloc_fs_devices(disk_super->fsid);
 602                 if (IS_ERR(fs_devices))
 603                         return PTR_ERR(fs_devices);
 604
 605                 list_add(&fs_devices->list, &fs_uuids);
 606
 607                 device = NULL;
 608         } else {
 609                 device = __find_device(&fs_devices->devices, devid,
 610                                        disk_super->dev_item.uuid);
 611         }
 612
 613         if (!device) {
 614                 if (fs_devices->opened)
 615                         return -EBUSY;
 616
 617                 device = btrfs_alloc_device(NULL, &devid,
 618                                             disk_super->dev_item.uuid);
 619                 if (IS_ERR(device)) {
 620                         /* we can safely leave the fs_devices entry around */
 621                         return PTR_ERR(device);
 622                 }
 623
 624                 name = rcu_string_strdup(path, GFP_NOFS);
 625                 if (!name) {
 626                         kfree(device);
 627                         return -ENOMEM;
 628                 }
 629                 rcu_assign_pointer(device->name, name);
 630
 631                 mutex_lock(&fs_devices->device_list_mutex);
 632                 list_add_rcu(&device->dev_list, &fs_devices->devices);
 633                 fs_devices->num_devices++;
 634                 mutex_unlock(&fs_devices->device_list_mutex);
 635
 636                 ret = 1;
 637                 device->fs_devices = fs_devices;
 638         } else if (!device->name || strcmp(device->name->str, path)) {
 639                 /*
 640                  * When FS is already mounted.
 641                  * 1. If you are here and if the device->name is NULL that
 642                  *    means this device was missing at time of FS mount.
 643                  * 2. If you are here and if the device->name is different
 644                  *    from 'path' that means either
 645                  *      a. The same device disappeared and reappeared with
 646                  *         different name. or
 647                  *      b. The missing-disk-which-was-replaced, has
 648                  *         reappeared now.
 649                  *
 650                  * We must allow 1 and 2a above. But 2b would be a spurious
 651                  * and unintentional.
 652                  *
 653                  * Further in case of 1 and 2a above, the disk at 'path'
 654                  * would have missed some transaction when it was away and
 655                  * in case of 2a the stale bdev has to be updated as well.
 656                  * 2b must not be allowed at all time.
 657                  */
 658
 659                 /*
 660                  * For now, we do allow update to btrfs_fs_device through the
 661                  * btrfs dev scan cli after FS has been mounted.  We're still
 662                  * tracking a problem where systems fail mount by subvolume id
 663                  * when we reject replacement on a mounted FS.
 664                  */
 665                 if (!fs_devices->opened && found_transid < device->generation) {
 666                         /*
 667                          * That is if the FS is _not_ mounted and if you
 668                          * are here, that means there is more than one
 669                          * disk with same uuid and devid.We keep the one
 670                          * with larger generation number or the last-in if
 671                          * generation are equal.
 672                          */
 673                         return -EEXIST;
 674                 }
 675
 676                 name = rcu_string_strdup(path, GFP_NOFS);
 677                 if (!name)
 678                         return -ENOMEM;
 679                 rcu_string_free(device->name);
 680                 rcu_assign_pointer(device->name, name);
 681                 if (device->missing) {
 682                         fs_devices->missing_devices--;
 683                         device->missing = 0;
 684                 }
 685         }
 686
 687         /*
 688          * Unmount does not free the btrfs_device struct but would zero
 689          * generation along with most of the other members. So just update
 690          * it back. We need it to pick the disk with largest generation
 691          * (as above).
 692          */
 693         if (!fs_devices->opened)
 694                 device->generation = found_transid;
 695
 696         /*
 697          * if there is new btrfs on an already registered device,
 698          * then remove the stale device entry.
 699          */
 700         btrfs_free_stale_device(device);
 701
 702         *fs_devices_ret = fs_devices;
 703
 704         return ret;
 705 }
 706
 707 static struct btrfs_fs_devices *clone_fs_devices(struct btrfs_fs_devices *orig)
 708 {
 709         struct btrfs_fs_devices *fs_devices;
 710         struct btrfs_device *device;
 711         struct btrfs_device *orig_dev;
 712
 713         fs_devices = alloc_fs_devices(orig->fsid);
 714         if (IS_ERR(fs_devices))
 715                 return fs_devices;
 716
 717         mutex_lock(&orig->device_list_mutex);
 718         fs_devices->total_devices = orig->total_devices;
 719
 720         /* We have held the volume lock, it is safe to get the devices. */
 721         list_for_each_entry(orig_dev, &orig->devices, dev_list) {
 722                 struct rcu_string *name;
 723
 724                 device = btrfs_alloc_device(NULL, &orig_dev->devid,
 725                                             orig_dev->uuid);
 726                 if (IS_ERR(device))
 727                         goto error;
 728
 729                 /*
 730                  * This is ok to do without rcu read locked because we hold the
 731                  * uuid mutex so nothing we touch in here is going to disappear.
 732                  */
 733                 if (orig_dev->name) {
 734                         name = rcu_string_strdup(orig_dev->name->str, GFP_NOFS);
 735                         if (!name) {
 736                                 kfree(device);
 737                                 goto error;
 738                         }
 739                         rcu_assign_pointer(device->name, name);
 740                 }
 741
 742                 list_add(&device->dev_list, &fs_devices->devices);
 743                 device->fs_devices = fs_devices;
 744                 fs_devices->num_devices++;
 745         }
 746         mutex_unlock(&orig->device_list_mutex);
 747         return fs_devices;
 748 error:
 749         mutex_unlock(&orig->device_list_mutex);
 750         free_fs_devices(fs_devices);
 751         return ERR_PTR(-ENOMEM);
 752 }
 753
 754 void btrfs_close_extra_devices(struct btrfs_fs_devices *fs_devices, int step)
 755 {
 756         struct btrfs_device *device, *next;
 757         struct btrfs_device *latest_dev = NULL;
 758
 759         mutex_lock(&uuid_mutex);
 760 again:
 761         /* This is the initialized path, it is safe to release the devices. */
 762         list_for_each_entry_safe(device, next, &fs_devices->devices, dev_list) {
 763                 if (device->in_fs_metadata) {
 764                         if (!device->is_tgtdev_for_dev_replace &&
 765                             (!latest_dev ||
 766                              device->generation > latest_dev->generation)) {
 767                                 latest_dev = device;
 768                         }
 769                         continue;
 770                 }
 771
 772                 if (device->devid == BTRFS_DEV_REPLACE_DEVID) {
 773                         /*
 774                          * In the first step, keep the device which has
 775                          * the correct fsid and the devid that is used
 776                          * for the dev_replace procedure.
 777                          * In the second step, the dev_replace state is
 778                          * read from the device tree and it is known
 779                          * whether the procedure is really active or
 780                          * not, which means whether this device is
 781                          * used or whether it should be removed.
 782                          */
 783                         if (step == 0 || device->is_tgtdev_for_dev_replace) {
 784                                 continue;
 785                         }
 786                 }
 787                 if (device->bdev) {
 788                         blkdev_put(device->bdev, device->mode);
 789                         device->bdev = NULL;
 790                         fs_devices->open_devices--;
 791                 }
 792                 if (device->writeable) {
 793                         list_del_init(&device->dev_alloc_list);
 794                         device->writeable = 0;
 795                         if (!device->is_tgtdev_for_dev_replace)
 796                                 fs_devices->rw_devices--;
 797                 }
 798                 list_del_init(&device->dev_list);
 799                 fs_devices->num_devices--;
 800                 rcu_string_free(device->name);
 801                 kfree(device);
 802         }
 803
 804         if (fs_devices->seed) {
 805                 fs_devices = fs_devices->seed;
 806                 goto again;
 807         }
 808
 809         fs_devices->latest_bdev = latest_dev->bdev;
 810
 811         mutex_unlock(&uuid_mutex);
 812 }
 813
 814 static void __free_device(struct work_struct *work)
 815 {
 816         struct btrfs_device *device;
 817
 818         device = container_of(work, struct btrfs_device, rcu_work);
 819
 820         if (device->bdev)
 821                 blkdev_put(device->bdev, device->mode);
 822
 823         rcu_string_free(device->name);
 824         kfree(device);
 825 }
 826
 827 static void free_device(struct rcu_head *head)
 828 {
 829         struct btrfs_device *device;
 830
 831         device = container_of(head, struct btrfs_device, rcu);
 832
 833         INIT_WORK(&device->rcu_work, __free_device);
 834         schedule_work(&device->rcu_work);
 835 }
 836
 837 static int __btrfs_close_devices(struct btrfs_fs_devices *fs_devices)
 838 {
 839         struct btrfs_device *device, *tmp;
 840
 841         if (--fs_devices->opened > 0)
 842                 return 0;
 843
 844         mutex_lock(&fs_devices->device_list_mutex);
 845         list_for_each_entry_safe(device, tmp, &fs_devices->devices, dev_list) {
 846                 btrfs_close_one_device(device);
 847         }
 848         mutex_unlock(&fs_devices->device_list_mutex);
 849
 850         WARN_ON(fs_devices->open_devices);
 851         WARN_ON(fs_devices->rw_devices);
 852         fs_devices->opened = 0;
 853         fs_devices->seeding = 0;
 854
 855         return 0;
 856 }
 857
 858 int btrfs_close_devices(struct btrfs_fs_devices *fs_devices)
 859 {
 860         struct btrfs_fs_devices *seed_devices = NULL;
 861         int ret;
 862
 863         mutex_lock(&uuid_mutex);
 864         ret = __btrfs_close_devices(fs_devices);
 865         if (!fs_devices->opened) {
 866                 seed_devices = fs_devices->seed;
 867                 fs_devices->seed = NULL;
 868         }
 869         mutex_unlock(&uuid_mutex);
 870
 871         while (seed_devices) {
 872                 fs_devices = seed_devices;
 873                 seed_devices = fs_devices->seed;
 874                 __btrfs_close_devices(fs_devices);
 875                 free_fs_devices(fs_devices);
 876         }
 877         /*
 878          * Wait for rcu kworkers under __btrfs_close_devices
 879          * to finish all blkdev_puts so device is really
 880          * free when umount is done.
 881          */
 882         rcu_barrier();
 883         return ret;
 884 }
 885
 886 static int __btrfs_open_devices(struct btrfs_fs_devices *fs_devices,
 887                                 fmode_t flags, void *holder)
 888 {
 889         struct request_queue *q;
 890         struct block_device *bdev;
 891         struct list_head *head = &fs_devices->devices;
 892         struct btrfs_device *device;
 893         struct btrfs_device *latest_dev = NULL;
 894         struct buffer_head *bh;
 895         struct btrfs_super_block *disk_super;
 896         u64 devid;
 897         int seeding = 1;
 898         int ret = 0;
 899
 900         flags |= FMODE_EXCL;
 901
 902         list_for_each_entry(device, head, dev_list) {
 903                 if (device->bdev)
 904                         continue;
 905                 if (!device->name)
 906                         continue;
 907
 908                 /* Just open everything we can; ignore failures here */
 909                 if (btrfs_get_bdev_and_sb(device->name->str, flags, holder, 1,
 910                                             &bdev, &bh))
 911                         continue;
 912
 913                 disk_super = (struct btrfs_super_block *)bh->b_data;
 914                 devid = btrfs_stack_device_id(&disk_super->dev_item);
 915                 if (devid != device->devid)
 916                         goto error_brelse;
 917
 918                 if (memcmp(device->uuid, disk_super->dev_item.uuid,
 919                            BTRFS_UUID_SIZE))
 920                         goto error_brelse;
 921
 922                 device->generation = btrfs_super_generation(disk_super);
 923                 if (!latest_dev ||
 924                     device->generation > latest_dev->generation)
 925                         latest_dev = device;
 926
 927                 if (btrfs_super_flags(disk_super) & BTRFS_SUPER_FLAG_SEEDING) {
 928                         device->writeable = 0;
 929                 } else {
 930                         device->writeable = !bdev_read_only(bdev);
 931                         seeding = 0;
 932                 }
 933
 934                 q = bdev_get_queue(bdev);
 935                 if (blk_queue_discard(q))
 936                         device->can_discard = 1;
 937
 938                 device->bdev = bdev;
 939                 device->in_fs_metadata = 0;
 940                 device->mode = flags;
 941
 942                 if (!blk_queue_nonrot(bdev_get_queue(bdev)))
 943                         fs_devices->rotating = 1;
 944
 945                 fs_devices->open_devices++;
 946                 if (device->writeable &&
 947                     device->devid != BTRFS_DEV_REPLACE_DEVID) {
 948                         fs_devices->rw_devices++;
 949                         list_add(&device->dev_alloc_list,
 950                                  &fs_devices->alloc_list);
 951                 }
 952                 brelse(bh);
 953                 continue;
 954
 955 error_brelse:
 956                 brelse(bh);
 957                 blkdev_put(bdev, flags);
 958                 continue;
 959         }
 960         if (fs_devices->open_devices == 0) {
 961                 ret = -EINVAL;
 962                 goto out;
 963         }
 964         fs_devices->seeding = seeding;
 965         fs_devices->opened = 1;
 966         fs_devices->latest_bdev = latest_dev->bdev;
 967         fs_devices->total_rw_bytes = 0;
 968 out:
 969         return ret;
 970 }
 971
 972 int btrfs_open_devices(struct btrfs_fs_devices *fs_devices,
 973                        fmode_t flags, void *holder)
 974 {
 975         int ret;
 976
 977         mutex_lock(&uuid_mutex);
 978         if (fs_devices->opened) {
 979                 fs_devices->opened++;
 980                 ret = 0;
 981         } else {
 982                 ret = __btrfs_open_devices(fs_devices, flags, holder);
 983         }
 984         mutex_unlock(&uuid_mutex);
 985         return ret;
 986 }
 987
 988 /*
 989  * Look for a btrfs signature on a device. This may be called out of the mount path
 990  * and we are not allowed to call set_blocksize during the scan. The superblock
 991  * is read via pagecache
 992  */
 993 int btrfs_scan_one_device(const char *path, fmode_t flags, void *holder,
 994                           struct btrfs_fs_devices **fs_devices_ret)
 995 {
 996         struct btrfs_super_block *disk_super;
 997         struct block_device *bdev;
 998         struct page *page;
 999         void *p;
1000         int ret = -EINVAL;
1001         u64 devid;
1002         u64 transid;
1003         u64 total_devices;
1004         u64 bytenr;
1005         pgoff_t index;
1006
1007         /*
1008          * we would like to check all the supers, but that would make
1009          * a btrfs mount succeed after a mkfs from a different FS.
1010          * So, we need to add a special mount option to scan for
1011          * later supers, using BTRFS_SUPER_MIRROR_MAX instead
1012          */
1013         bytenr = btrfs_sb_offset(0);
1014         flags |= FMODE_EXCL;
1015         mutex_lock(&uuid_mutex);
1016
1017         bdev = blkdev_get_by_path(path, flags, holder);
1018
1019         if (IS_ERR(bdev)) {
1020                 ret = PTR_ERR(bdev);
1021                 goto error;
1022         }
1023
1024         /* make sure our super fits in the device */
1025         if (bytenr + PAGE_CACHE_SIZE >= i_size_read(bdev->bd_inode))
1026                 goto error_bdev_put;
1027
1028         /* make sure our super fits in the page */
1029         if (sizeof(*disk_super) > PAGE_CACHE_SIZE)
1030                 goto error_bdev_put;
1031
1032         /* make sure our super doesn't straddle pages on disk */
1033         index = bytenr >> PAGE_CACHE_SHIFT;
1034         if ((bytenr + sizeof(*disk_super) - 1) >> PAGE_CACHE_SHIFT != index)
1035                 goto error_bdev_put;
1036
1037         /* pull in the page with our super */
1038         page = read_cache_page_gfp(bdev->bd_inode->i_mapping,
1039                                    index, GFP_NOFS);
1040
1041         if (IS_ERR_OR_NULL(page))
1042                 goto error_bdev_put;
1043
1044         p = kmap(page);
1045
1046         /* align our pointer to the offset of the super block */
1047         disk_super = p + (bytenr & ~PAGE_CACHE_MASK);
1048
1049         if (btrfs_super_bytenr(disk_super) != bytenr ||
1050             btrfs_super_magic(disk_super) != BTRFS_MAGIC)
1051                 goto error_unmap;
1052
1053         devid = btrfs_stack_device_id(&disk_super->dev_item);
1054         transid = btrfs_super_generation(disk_super);
1055         total_devices = btrfs_super_num_devices(disk_super);
1056
1057         ret = device_list_add(path, disk_super, devid, fs_devices_ret);
1058         if (ret > 0) {
1059                 if (disk_super->label[0]) {
1060                         if (disk_super->label[BTRFS_LABEL_SIZE - 1])
1061                                 disk_super->label[BTRFS_LABEL_SIZE - 1] = '\0';
1062                         printk(KERN_INFO "BTRFS: device label %s ", disk_super->label);
1063                 } else {
1064                         printk(KERN_INFO "BTRFS: device fsid %pU ", disk_super->fsid);
1065                 }
1066
1067                 printk(KERN_CONT "devid %llu transid %llu %s\n", devid, transid, path);
1068                 ret = 0;
1069         }
1070         if (!ret && fs_devices_ret)
1071                 (*fs_devices_ret)->total_devices = total_devices;
1072
1073 error_unmap:
1074         kunmap(page);
1075         page_cache_release(page);
1076
1077 error_bdev_put:
1078         blkdev_put(bdev, flags);
1079 error:
1080         mutex_unlock(&uuid_mutex);
1081         return ret;
1082 }
1083
1084 /* helper to account the used device space in the range */
1085 int btrfs_account_dev_extents_size(struct btrfs_device *device, u64 start,
1086                                    u64 end, u64 *length)
1087 {
1088         struct btrfs_key key;
1089         struct btrfs_root *root = device->dev_root;
1090         struct btrfs_dev_extent *dev_extent;
1091         struct btrfs_path *path;
1092         u64 extent_end;
1093         int ret;
1094         int slot;
1095         struct extent_buffer *l;
1096
1097         *length = 0;
1098
1099         if (start >= device->total_bytes || device->is_tgtdev_for_dev_replace)
1100                 return 0;
1101
1102         path = btrfs_alloc_path();
1103         if (!path)
1104                 return -ENOMEM;
1105         path->reada = 2;
1106
1107         key.objectid = device->devid;
1108         key.offset = start;
1109         key.type = BTRFS_DEV_EXTENT_KEY;
1110
1111         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
1112         if (ret < 0)
1113                 goto out;
1114         if (ret > 0) {
1115                 ret = btrfs_previous_item(root, path, key.objectid, key.type);
1116                 if (ret < 0)
1117                         goto out;
1118         }
1119
1120         while (1) {
1121                 l = path->nodes[0];
1122                 slot = path->slots[0];
1123                 if (slot >= btrfs_header_nritems(l)) {
1124                         ret = btrfs_next_leaf(root, path);
1125                         if (ret == 0)
1126                                 continue;
1127                         if (ret < 0)
1128                                 goto out;
1129
1130                         break;
1131                 }
1132                 btrfs_item_key_to_cpu(l, &key, slot);
1133
1134                 if (key.objectid < device->devid)
1135                         goto next;
1136
1137                 if (key.objectid > device->devid)
1138                         break;
1139
1140                 if (key.type != BTRFS_DEV_EXTENT_KEY)
1141                         goto next;
1142
1143                 dev_extent = btrfs_item_ptr(l, slot, struct btrfs_dev_extent);
1144                 extent_end = key.offset + btrfs_dev_extent_length(l,
1145                                                                   dev_extent);
1146                 if (key.offset <= start && extent_end > end) {
1147                         *length = end - start + 1;
1148                         break;
1149                 } else if (key.offset <= start && extent_end > start)
1150                         *length += extent_end - start;
1151                 else if (key.offset > start && extent_end <= end)
1152                         *length += extent_end - key.offset;
1153                 else if (key.offset > start && key.offset <= end) {
1154                         *length += end - key.offset + 1;
1155                         break;
1156                 } else if (key.offset > end)
1157                         break;
1158
1159 next:
1160                 path->slots[0]++;
1161         }
1162         ret = 0;
1163 out:
1164         btrfs_free_path(path);
1165         return ret;
1166 }
1167
1168 static int contains_pending_extent(struct btrfs_transaction *transaction,
1169                                    struct btrfs_device *device,
1170                                    u64 *start, u64 len)
1171 {
1172         struct btrfs_fs_info *fs_info = device->dev_root->fs_info;
1173         struct extent_map *em;
1174         struct list_head *search_list = &fs_info->pinned_chunks;
1175         int ret = 0;
1176         u64 physical_start = *start;
1177
1178         if (transaction)
1179                 search_list = &transaction->pending_chunks;
1180 again:
1181         list_for_each_entry(em, search_list, list) {
1182                 struct map_lookup *map;
1183                 int i;
1184
1185                 map = (struct map_lookup *)em->bdev;
1186                 for (i = 0; i < map->num_stripes; i++) {
1187                         u64 end;
1188
1189                         if (map->stripes[i].dev != device)
1190                                 continue;
1191                         if (map->stripes[i].physical >= physical_start + len ||
1192                             map->stripes[i].physical + em->orig_block_len <=
1193                             physical_start)
1194                                 continue;
1195                         /*
1196                          * Make sure that while processing the pinned list we do
1197                          * not override our *start with a lower value, because
1198                          * we can have pinned chunks that fall within this
1199                          * device hole and that have lower physical addresses
1200                          * than the pending chunks we processed before. If we
1201                          * do not take this special care we can end up getting
1202                          * 2 pending chunks that start at the same physical
1203                          * device offsets because the end offset of a pinned
1204                          * chunk can be equal to the start offset of some
1205                          * pending chunk.
1206                          */
1207                         end = map->stripes[i].physical + em->orig_block_len;
1208                         if (end > *start) {
1209                                 *start = end;
1210                                 ret = 1;
1211                         }
1212                 }
1213         }
1214         if (search_list != &fs_info->pinned_chunks) {
1215                 search_list = &fs_info->pinned_chunks;
1216                 goto again;
1217         }
1218
1219         return ret;
1220 }
1221
1222
1223 /*
1224  * find_free_dev_extent_start - find free space in the specified device
1225  * @device:       the device which we search the free space in
1226  * @num_bytes:    the size of the free space that we need
1227  * @search_start: the position from which to begin the search
1228  * @start:        store the start of the free space.
1229  * @len:          the size of the free space. that we find, or the size
1230  *                of the max free space if we don't find suitable free space
1231  *
1232  * this uses a pretty simple search, the expectation is that it is
1233  * called very infrequently and that a given device has a small number
1234  * of extents
1235  *
1236  * @start is used to store the start of the free space if we find. But if we
1237  * don't find suitable free space, it will be used to store the start position
1238  * of the max free space.
1239  *
1240  * @len is used to store the size of the free space that we find.
1241  * But if we don't find suitable free space, it is used to store the size of
1242  * the max free space.
1243  */
1244 int find_free_dev_extent_start(struct btrfs_transaction *transaction,
1245                                struct btrfs_device *device, u64 num_bytes,
1246                                u64 search_start, u64 *start, u64 *len)
1247 {
1248         struct btrfs_key key;
1249         struct btrfs_root *root = device->dev_root;
1250         struct btrfs_dev_extent *dev_extent;
1251         struct btrfs_path *path;
1252         u64 hole_size;
1253         u64 max_hole_start;
1254         u64 max_hole_size;
1255         u64 extent_end;
1256         u64 search_end = device->total_bytes;
1257         int ret;
1258         int slot;
1259         struct extent_buffer *l;
1260
1261         path = btrfs_alloc_path();
1262         if (!path)
1263                 return -ENOMEM;
1264
1265         max_hole_start = search_start;
1266         max_hole_size = 0;
1267
1268 again:
1269         if (search_start >= search_end || device->is_tgtdev_for_dev_replace) {
1270                 ret = -ENOSPC;
1271                 goto out;
1272         }
1273
1274         path->reada = 2;
1275         path->search_commit_root = 1;
1276         path->skip_locking = 1;
1277
1278         key.objectid = device->devid;
1279         key.offset = search_start;
1280         key.type = BTRFS_DEV_EXTENT_KEY;
1281
1282         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
1283         if (ret < 0)
1284                 goto out;
1285         if (ret > 0) {
1286                 ret = btrfs_previous_item(root, path, key.objectid, key.type);
1287                 if (ret < 0)
1288                         goto out;
1289         }
1290
1291         while (1) {
1292                 l = path->nodes[0];
1293                 slot = path->slots[0];
1294                 if (slot >= btrfs_header_nritems(l)) {
1295                         ret = btrfs_next_leaf(root, path);
1296                         if (ret == 0)
1297                                 continue;
1298                         if (ret < 0)
1299                                 goto out;
1300
1301                         break;
1302                 }
1303                 btrfs_item_key_to_cpu(l, &key, slot);
1304
1305                 if (key.objectid < device->devid)
1306                         goto next;
1307
1308                 if (key.objectid > device->devid)
1309                         break;
1310
1311                 if (key.type != BTRFS_DEV_EXTENT_KEY)
1312                         goto next;
1313
1314                 if (key.offset > search_start) {
1315                         hole_size = key.offset - search_start;
1316
1317                         /*
1318                          * Have to check before we set max_hole_start, otherwise
1319                          * we could end up sending back this offset anyway.
1320                          */
1321                         if (contains_pending_extent(transaction, device,
1322                                                     &search_start,
1323                                                     hole_size)) {
1324                                 if (key.offset >= search_start) {
1325                                         hole_size = key.offset - search_start;
1326                                 } else {
1327                                         WARN_ON_ONCE(1);
1328                                         hole_size = 0;
1329                                 }
1330                         }
1331
1332                         if (hole_size > max_hole_size) {
1333                                 max_hole_start = search_start;
1334                                 max_hole_size = hole_size;
1335                         }
1336
1337                         /*
1338                          * If this free space is greater than which we need,
1339                          * it must be the max free space that we have found
1340                          * until now, so max_hole_start must point to the start
1341                          * of this free space and the length of this free space
1342                          * is stored in max_hole_size. Thus, we return
1343                          * max_hole_start and max_hole_size and go back to the
1344                          * caller.
1345                          */
1346                         if (hole_size >= num_bytes) {
1347                                 ret = 0;
1348                                 goto out;
1349                         }
1350                 }
1351
1352                 dev_extent = btrfs_item_ptr(l, slot, struct btrfs_dev_extent);
1353                 extent_end = key.offset + btrfs_dev_extent_length(l,
1354                                                                   dev_extent);
1355                 if (extent_end > search_start)
1356                         search_start = extent_end;
1357 next:
1358                 path->slots[0]++;
1359                 cond_resched();
1360         }
1361
1362         /*
1363          * At this point, search_start should be the end of
1364          * allocated dev extents, and when shrinking the device,
1365          * search_end may be smaller than search_start.
1366          */
1367         if (search_end > search_start) {
1368                 hole_size = search_end - search_start;
1369
1370                 if (contains_pending_extent(transaction, device, &search_start,
1371                                             hole_size)) {
1372                         btrfs_release_path(path);
1373                         goto again;
1374                 }
1375
1376                 if (hole_size > max_hole_size) {
1377                         max_hole_start = search_start;
1378                         max_hole_size = hole_size;
1379                 }
1380         }
1381
1382         /* See above. */
1383         if (max_hole_size < num_bytes)
1384                 ret = -ENOSPC;
1385         else
1386                 ret = 0;
1387
1388 out:
1389         btrfs_free_path(path);
1390         *start = max_hole_start;
1391         if (len)
1392                 *len = max_hole_size;
1393         return ret;
1394 }
1395
1396 int find_free_dev_extent(struct btrfs_trans_handle *trans,
1397                          struct btrfs_device *device, u64 num_bytes,
1398                          u64 *start, u64 *len)
1399 {
1400         struct btrfs_root *root = device->dev_root;
1401         u64 search_start;
1402
1403         /* FIXME use last free of some kind */
1404
1405         /*
1406          * we don't want to overwrite the superblock on the drive,
1407          * so we make sure to start at an offset of at least 1MB
1408          */
1409         search_start = max(root->fs_info->alloc_start, 1024ull * 1024);
1410         return find_free_dev_extent_start(trans->transaction, device,
1411                                           num_bytes, search_start, start, len);
1412 }
1413
1414 static int btrfs_free_dev_extent(struct btrfs_trans_handle *trans,
1415                           struct btrfs_device *device,
1416                           u64 start, u64 *dev_extent_len)
1417 {
1418         int ret;
1419         struct btrfs_path *path;
1420         struct btrfs_root *root = device->dev_root;
1421         struct btrfs_key key;
1422         struct btrfs_key found_key;
1423         struct extent_buffer *leaf = NULL;
1424         struct btrfs_dev_extent *extent = NULL;
1425
1426         path = btrfs_alloc_path();
1427         if (!path)
1428                 return -ENOMEM;
1429
1430         key.objectid = device->devid;
1431         key.offset = start;
1432         key.type = BTRFS_DEV_EXTENT_KEY;
1433 again:
1434         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1435         if (ret > 0) {
1436                 ret = btrfs_previous_item(root, path, key.objectid,
1437                                           BTRFS_DEV_EXTENT_KEY);
1438                 if (ret)
1439                         goto out;
1440                 leaf = path->nodes[0];
1441                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
1442                 extent = btrfs_item_ptr(leaf, path->slots[0],
1443                                         struct btrfs_dev_extent);
1444                 BUG_ON(found_key.offset > start || found_key.offset +
1445                        btrfs_dev_extent_length(leaf, extent) < start);
1446                 key = found_key;
1447                 btrfs_release_path(path);
1448                 goto again;
1449         } else if (ret == 0) {
1450                 leaf = path->nodes[0];
1451                 extent = btrfs_item_ptr(leaf, path->slots[0],
1452                                         struct btrfs_dev_extent);
1453         } else {
1454                 btrfs_std_error(root->fs_info, ret, "Slot search failed");
1455                 goto out;
1456         }
1457
1458         *dev_extent_len = btrfs_dev_extent_length(leaf, extent);
1459
1460         ret = btrfs_del_item(trans, root, path);
1461         if (ret) {
1462                 btrfs_std_error(root->fs_info, ret,
1463                             "Failed to remove dev extent item");
1464         } else {
1465                 set_bit(BTRFS_TRANS_HAVE_FREE_BGS, &trans->transaction->flags);
1466         }
1467 out:
1468         btrfs_free_path(path);
1469         return ret;
1470 }
1471
1472 static int btrfs_alloc_dev_extent(struct btrfs_trans_handle *trans,
1473                                   struct btrfs_device *device,
1474                                   u64 chunk_tree, u64 chunk_objectid,
1475                                   u64 chunk_offset, u64 start, u64 num_bytes)
1476 {
1477         int ret;
1478         struct btrfs_path *path;
1479         struct btrfs_root *root = device->dev_root;
1480         struct btrfs_dev_extent *extent;
1481         struct extent_buffer *leaf;
1482         struct btrfs_key key;
1483
1484         WARN_ON(!device->in_fs_metadata);
1485         WARN_ON(device->is_tgtdev_for_dev_replace);
1486         path = btrfs_alloc_path();
1487         if (!path)
1488                 return -ENOMEM;
1489
1490         key.objectid = device->devid;
1491         key.offset = start;
1492         key.type = BTRFS_DEV_EXTENT_KEY;
1493         ret = btrfs_insert_empty_item(trans, root, path, &key,
1494                                       sizeof(*extent));
1495         if (ret)
1496                 goto out;
1497
1498         leaf = path->nodes[0];
1499         extent = btrfs_item_ptr(leaf, path->slots[0],
1500                                 struct btrfs_dev_extent);
1501         btrfs_set_dev_extent_chunk_tree(leaf, extent, chunk_tree);
1502         btrfs_set_dev_extent_chunk_objectid(leaf, extent, chunk_objectid);
1503         btrfs_set_dev_extent_chunk_offset(leaf, extent, chunk_offset);
1504
1505         write_extent_buffer(leaf, root->fs_info->chunk_tree_uuid,
1506                     btrfs_dev_extent_chunk_tree_uuid(extent), BTRFS_UUID_SIZE);
1507
1508         btrfs_set_dev_extent_length(leaf, extent, num_bytes);
1509         btrfs_mark_buffer_dirty(leaf);
1510 out:
1511         btrfs_free_path(path);
1512         return ret;
1513 }
1514
1515 static u64 find_next_chunk(struct btrfs_fs_info *fs_info)
1516 {
1517         struct extent_map_tree *em_tree;
1518         struct extent_map *em;
1519         struct rb_node *n;
1520         u64 ret = 0;
1521
1522         em_tree = &fs_info->mapping_tree.map_tree;
1523         read_lock(&em_tree->lock);
1524         n = rb_last(&em_tree->map);
1525         if (n) {
1526                 em = rb_entry(n, struct extent_map, rb_node);
1527                 ret = em->start + em->len;
1528         }
1529         read_unlock(&em_tree->lock);
1530
1531         return ret;
1532 }
1533
1534 static noinline int find_next_devid(struct btrfs_fs_info *fs_info,
1535                                     u64 *devid_ret)
1536 {
1537         int ret;
1538         struct btrfs_key key;
1539         struct btrfs_key found_key;
1540         struct btrfs_path *path;
1541
1542         path = btrfs_alloc_path();
1543         if (!path)
1544                 return -ENOMEM;
1545
1546         key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
1547         key.type = BTRFS_DEV_ITEM_KEY;
1548         key.offset = (u64)-1;
1549
1550         ret = btrfs_search_slot(NULL, fs_info->chunk_root, &key, path, 0, 0);
1551         if (ret < 0)
1552                 goto error;
1553
1554         BUG_ON(ret == 0); /* Corruption */
1555
1556         ret = btrfs_previous_item(fs_info->chunk_root, path,
1557                                   BTRFS_DEV_ITEMS_OBJECTID,
1558                                   BTRFS_DEV_ITEM_KEY);
1559         if (ret) {
1560                 *devid_ret = 1;
1561         } else {
1562                 btrfs_item_key_to_cpu(path->nodes[0], &found_key,
1563                                       path->slots[0]);
1564                 *devid_ret = found_key.offset + 1;
1565         }
1566         ret = 0;
1567 error:
1568         btrfs_free_path(path);
1569         return ret;
1570 }
1571
1572 /*
1573  * the device information is stored in the chunk root
1574  * the btrfs_device struct should be fully filled in
1575  */
1576 static int btrfs_add_device(struct btrfs_trans_handle *trans,
1577                             struct btrfs_root *root,
1578                             struct btrfs_device *device)
1579 {
1580         int ret;
1581         struct btrfs_path *path;
1582         struct btrfs_dev_item *dev_item;
1583         struct extent_buffer *leaf;
1584         struct btrfs_key key;
1585         unsigned long ptr;
1586
1587         root = root->fs_info->chunk_root;
1588
1589         path = btrfs_alloc_path();
1590         if (!path)
1591                 return -ENOMEM;
1592
1593         key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
1594         key.type = BTRFS_DEV_ITEM_KEY;
1595         key.offset = device->devid;
1596
1597         ret = btrfs_insert_empty_item(trans, root, path, &key,
1598                                       sizeof(*dev_item));
1599         if (ret)
1600                 goto out;
1601
1602         leaf = path->nodes[0];
1603         dev_item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_dev_item);
1604
1605         btrfs_set_device_id(leaf, dev_item, device->devid);
1606         btrfs_set_device_generation(leaf, dev_item, 0);
1607         btrfs_set_device_type(leaf, dev_item, device->type);
1608         btrfs_set_device_io_align(leaf, dev_item, device->io_align);
1609         btrfs_set_device_io_width(leaf, dev_item, device->io_width);
1610         btrfs_set_device_sector_size(leaf, dev_item, device->sector_size);
1611         btrfs_set_device_total_bytes(leaf, dev_item,
1612                                      btrfs_device_get_disk_total_bytes(device));
1613         btrfs_set_device_bytes_used(leaf, dev_item,
1614                                     btrfs_device_get_bytes_used(device));
1615         btrfs_set_device_group(leaf, dev_item, 0);
1616         btrfs_set_device_seek_speed(leaf, dev_item, 0);
1617         btrfs_set_device_bandwidth(leaf, dev_item, 0);
1618         btrfs_set_device_start_offset(leaf, dev_item, 0);
1619
1620         ptr = btrfs_device_uuid(dev_item);
1621         write_extent_buffer(leaf, device->uuid, ptr, BTRFS_UUID_SIZE);
1622         ptr = btrfs_device_fsid(dev_item);
1623         write_extent_buffer(leaf, root->fs_info->fsid, ptr, BTRFS_UUID_SIZE);
1624         btrfs_mark_buffer_dirty(leaf);
1625
1626         ret = 0;
1627 out:
1628         btrfs_free_path(path);
1629         return ret;
1630 }
1631
1632 /*
1633  * Function to update ctime/mtime for a given device path.
1634  * Mainly used for ctime/mtime based probe like libblkid.
1635  */
1636 static void update_dev_time(char *path_name)
1637 {
1638         struct file *filp;
1639
1640         filp = filp_open(path_name, O_RDWR, 0);
1641         if (IS_ERR(filp))
1642                 return;
1643         file_update_time(filp);
1644         filp_close(filp, NULL);
1645         return;
1646 }
1647
1648 static int btrfs_rm_dev_item(struct btrfs_root *root,
1649                              struct btrfs_device *device)
1650 {
1651         int ret;
1652         struct btrfs_path *path;
1653         struct btrfs_key key;
1654         struct btrfs_trans_handle *trans;
1655
1656         root = root->fs_info->chunk_root;
1657
1658         path = btrfs_alloc_path();
1659         if (!path)
1660                 return -ENOMEM;
1661
1662         trans = btrfs_start_transaction(root, 0);
1663         if (IS_ERR(trans)) {
1664                 btrfs_free_path(path);
1665                 return PTR_ERR(trans);
1666         }
1667         key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
1668         key.type = BTRFS_DEV_ITEM_KEY;
1669         key.offset = device->devid;
1670
1671         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1672         if (ret < 0)
1673                 goto out;
1674
1675         if (ret > 0) {
1676                 ret = -ENOENT;
1677                 goto out;
1678         }
1679
1680         ret = btrfs_del_item(trans, root, path);
1681         if (ret)
1682                 goto out;
1683 out:
1684         btrfs_free_path(path);
1685         btrfs_commit_transaction(trans, root);
1686         return ret;
1687 }
1688
1689 int btrfs_rm_device(struct btrfs_root *root, char *device_path)
1690 {
1691         struct btrfs_device *device;
1692         struct btrfs_device *next_device;
1693         struct block_device *bdev;
1694         struct buffer_head *bh = NULL;
1695         struct btrfs_super_block *disk_super;
1696         struct btrfs_fs_devices *cur_devices;
1697         u64 all_avail;
1698         u64 devid;
1699         u64 num_devices;
1700         u8 *dev_uuid;
1701         unsigned seq;
1702         int ret = 0;
1703         bool clear_super = false;
1704
1705         mutex_lock(&uuid_mutex);
1706
1707         do {
1708                 seq = read_seqbegin(&root->fs_info->profiles_lock);
1709
1710                 all_avail = root->fs_info->avail_data_alloc_bits |
1711                             root->fs_info->avail_system_alloc_bits |
1712                             root->fs_info->avail_metadata_alloc_bits;
1713         } while (read_seqretry(&root->fs_info->profiles_lock, seq));
1714
1715         num_devices = root->fs_info->fs_devices->num_devices;
1716         btrfs_dev_replace_lock(&root->fs_info->dev_replace);
1717         if (btrfs_dev_replace_is_ongoing(&root->fs_info->dev_replace)) {
1718                 WARN_ON(num_devices < 1);
1719                 num_devices--;
1720         }
1721         btrfs_dev_replace_unlock(&root->fs_info->dev_replace);
1722
1723         if ((all_avail & BTRFS_BLOCK_GROUP_RAID10) && num_devices <= 4) {
1724                 ret = BTRFS_ERROR_DEV_RAID10_MIN_NOT_MET;
1725                 goto out;
1726         }
1727
1728         if ((all_avail & BTRFS_BLOCK_GROUP_RAID1) && num_devices <= 2) {
1729                 ret = BTRFS_ERROR_DEV_RAID1_MIN_NOT_MET;
1730                 goto out;
1731         }
1732
1733         if ((all_avail & BTRFS_BLOCK_GROUP_RAID5) &&
1734             root->fs_info->fs_devices->rw_devices <= 2) {
1735                 ret = BTRFS_ERROR_DEV_RAID5_MIN_NOT_MET;
1736                 goto out;
1737         }
1738         if ((all_avail & BTRFS_BLOCK_GROUP_RAID6) &&
1739             root->fs_info->fs_devices->rw_devices <= 3) {
1740                 ret = BTRFS_ERROR_DEV_RAID6_MIN_NOT_MET;
1741                 goto out;
1742         }
1743
1744         if (strcmp(device_path, "missing") == 0) {
1745                 struct list_head *devices;
1746                 struct btrfs_device *tmp;
1747
1748                 device = NULL;
1749                 devices = &root->fs_info->fs_devices->devices;
1750                 /*
1751                  * It is safe to read the devices since the volume_mutex
1752                  * is held.
1753                  */
1754                 list_for_each_entry(tmp, devices, dev_list) {
1755                         if (tmp->in_fs_metadata &&
1756                             !tmp->is_tgtdev_for_dev_replace &&
1757                             !tmp->bdev) {
1758                                 device = tmp;
1759                                 break;
1760                         }
1761                 }
1762                 bdev = NULL;
1763                 bh = NULL;
1764                 disk_super = NULL;
1765                 if (!device) {
1766                         ret = BTRFS_ERROR_DEV_MISSING_NOT_FOUND;
1767                         goto out;
1768                 }
1769         } else {
1770                 ret = btrfs_get_bdev_and_sb(device_path,
1771                                             FMODE_WRITE | FMODE_EXCL,
1772                                             root->fs_info->bdev_holder, 0,
1773                                             &bdev, &bh);
1774                 if (ret)
1775                         goto out;
1776                 disk_super = (struct btrfs_super_block *)bh->b_data;
1777                 devid = btrfs_stack_device_id(&disk_super->dev_item);
1778                 dev_uuid = disk_super->dev_item.uuid;
1779                 device = btrfs_find_device(root->fs_info, devid, dev_uuid,
1780                                            disk_super->fsid);
1781                 if (!device) {
1782                         ret = -ENOENT;
1783                         goto error_brelse;
1784                 }
1785         }
1786
1787         if (device->is_tgtdev_for_dev_replace) {
1788                 ret = BTRFS_ERROR_DEV_TGT_REPLACE;
1789                 goto error_brelse;
1790         }
1791
1792         if (device->writeable && root->fs_info->fs_devices->rw_devices == 1) {
1793                 ret = BTRFS_ERROR_DEV_ONLY_WRITABLE;
1794                 goto error_brelse;
1795         }
1796
1797         if (device->writeable) {
1798                 lock_chunks(root);
1799                 list_del_init(&device->dev_alloc_list);
1800                 device->fs_devices->rw_devices--;
1801                 unlock_chunks(root);
1802                 clear_super = true;
1803         }
1804
1805         mutex_unlock(&uuid_mutex);
1806         ret = btrfs_shrink_device(device, 0);
1807         mutex_lock(&uuid_mutex);
1808         if (ret)
1809                 goto error_undo;
1810
1811         /*
1812          * TODO: the superblock still includes this device in its num_devices
1813          * counter although write_all_supers() is not locked out. This
1814          * could give a filesystem state which requires a degraded mount.
1815          */
1816         ret = btrfs_rm_dev_item(root->fs_info->chunk_root, device);
1817         if (ret)
1818                 goto error_undo;
1819
1820         device->in_fs_metadata = 0;
1821         btrfs_scrub_cancel_dev(root->fs_info, device);
1822
1823         /*
1824          * the device list mutex makes sure that we don't change
1825          * the device list while someone else is writing out all
1826          * the device supers. Whoever is writing all supers, should
1827          * lock the device list mutex before getting the number of
1828          * devices in the super block (super_copy). Conversely,
1829          * whoever updates the number of devices in the super block
1830          * (super_copy) should hold the device list mutex.
1831          */
1832
1833         cur_devices = device->fs_devices;
1834         mutex_lock(&root->fs_info->fs_devices->device_list_mutex);
1835         list_del_rcu(&device->dev_list);
1836
1837         device->fs_devices->num_devices--;
1838         device->fs_devices->total_devices--;
1839
1840         if (device->missing)
1841                 device->fs_devices->missing_devices--;
1842
1843         next_device = list_entry(root->fs_info->fs_devices->devices.next,
1844                                  struct btrfs_device, dev_list);
1845         if (device->bdev == root->fs_info->sb->s_bdev)
1846                 root->fs_info->sb->s_bdev = next_device->bdev;
1847         if (device->bdev == root->fs_info->fs_devices->latest_bdev)
1848                 root->fs_info->fs_devices->latest_bdev = next_device->bdev;
1849
1850         if (device->bdev) {
1851                 device->fs_devices->open_devices--;
1852                 /* remove sysfs entry */
1853                 btrfs_sysfs_rm_device_link(root->fs_info->fs_devices, device);
1854         }
1855
1856         call_rcu(&device->rcu, free_device);
1857
1858         num_devices = btrfs_super_num_devices(root->fs_info->super_copy) - 1;
1859         btrfs_set_super_num_devices(root->fs_info->super_copy, num_devices);
1860         mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
1861
1862         if (cur_devices->open_devices == 0) {
1863                 struct btrfs_fs_devices *fs_devices;
1864                 fs_devices = root->fs_info->fs_devices;
1865                 while (fs_devices) {
1866                         if (fs_devices->seed == cur_devices) {
1867                                 fs_devices->seed = cur_devices->seed;
1868                                 break;
1869                         }
1870                         fs_devices = fs_devices->seed;
1871                 }
1872                 cur_devices->seed = NULL;
1873                 __btrfs_close_devices(cur_devices);
1874                 free_fs_devices(cur_devices);
1875         }
1876
1877         root->fs_info->num_tolerated_disk_barrier_failures =
1878                 btrfs_calc_num_tolerated_disk_barrier_failures(root->fs_info);
1879
1880         /*
1881          * at this point, the device is zero sized.  We want to
1882          * remove it from the devices list and zero out the old super
1883          */
1884         if (clear_super && disk_super) {
1885                 u64 bytenr;
1886                 int i;
1887
1888                 /* make sure this device isn't detected as part of
1889                  * the FS anymore
1890                  */
1891                 memset(&disk_super->magic, 0, sizeof(disk_super->magic));
1892                 set_buffer_dirty(bh);
1893                 sync_dirty_buffer(bh);
1894
1895                 /* clear the mirror copies of super block on the disk
1896                  * being removed, 0th copy is been taken care above and
1897                  * the below would take of the rest
1898                  */
1899                 for (i = 1; i < BTRFS_SUPER_MIRROR_MAX; i++) {
1900                         bytenr = btrfs_sb_offset(i);
1901                         if (bytenr + BTRFS_SUPER_INFO_SIZE >=
1902                                         i_size_read(bdev->bd_inode))
1903                                 break;
1904
1905                         brelse(bh);
1906                         bh = __bread(bdev, bytenr / 4096,
1907                                         BTRFS_SUPER_INFO_SIZE);
1908                         if (!bh)
1909                                 continue;
1910
1911                         disk_super = (struct btrfs_super_block *)bh->b_data;
1912
1913                         if (btrfs_super_bytenr(disk_super) != bytenr ||
1914                                 btrfs_super_magic(disk_super) != BTRFS_MAGIC) {
1915                                 continue;
1916                         }
1917                         memset(&disk_super->magic, 0,
1918                                                 sizeof(disk_super->magic));
1919                         set_buffer_dirty(bh);
1920                         sync_dirty_buffer(bh);
1921                 }
1922         }
1923
1924         ret = 0;
1925
1926         if (bdev) {
1927                 /* Notify udev that device has changed */
1928                 btrfs_kobject_uevent(bdev, KOBJ_CHANGE);
1929
1930                 /* Update ctime/mtime for device path for libblkid */
1931                 update_dev_time(device_path);
1932         }
1933
1934 error_brelse:
1935         brelse(bh);
1936         if (bdev)
1937                 blkdev_put(bdev, FMODE_READ | FMODE_EXCL);
1938 out:
1939         mutex_unlock(&uuid_mutex);
1940         return ret;
1941 error_undo:
1942         if (device->writeable) {
1943                 lock_chunks(root);
1944                 list_add(&device->dev_alloc_list,
1945                          &root->fs_info->fs_devices->alloc_list);
1946                 device->fs_devices->rw_devices++;
1947                 unlock_chunks(root);
1948         }
1949         goto error_brelse;
1950 }
1951
1952 void btrfs_rm_dev_replace_remove_srcdev(struct btrfs_fs_info *fs_info,
1953                                         struct btrfs_device *srcdev)
1954 {
1955         struct btrfs_fs_devices *fs_devices;
1956
1957         WARN_ON(!mutex_is_locked(&fs_info->fs_devices->device_list_mutex));
1958
1959         /*
1960          * in case of fs with no seed, srcdev->fs_devices will point
1961          * to fs_devices of fs_info. However when the dev being replaced is
1962          * a seed dev it will point to the seed's local fs_devices. In short
1963          * srcdev will have its correct fs_devices in both the cases.
1964          */
1965         fs_devices = srcdev->fs_devices;
1966
1967         list_del_rcu(&srcdev->dev_list);
1968         list_del_rcu(&srcdev->dev_alloc_list);
1969         fs_devices->num_devices--;
1970         if (srcdev->missing)
1971                 fs_devices->missing_devices--;
1972
1973         if (srcdev->writeable) {
1974                 fs_devices->rw_devices--;
1975                 /* zero out the old super if it is writable */
1976                 btrfs_scratch_superblocks(srcdev->bdev, srcdev->name->str);
1977         }
1978
1979         if (srcdev->bdev)
1980                 fs_devices->open_devices--;
1981 }
1982
1983 void btrfs_rm_dev_replace_free_srcdev(struct btrfs_fs_info *fs_info,
1984                                       struct btrfs_device *srcdev)
1985 {
1986         struct btrfs_fs_devices *fs_devices = srcdev->fs_devices;
1987
1988         call_rcu(&srcdev->rcu, free_device);
1989
1990         /*
1991          * unless fs_devices is seed fs, num_devices shouldn't go
1992          * zero
1993          */
1994         BUG_ON(!fs_devices->num_devices && !fs_devices->seeding);
1995
1996         /* if this is no devs we rather delete the fs_devices */
1997         if (!fs_devices->num_devices) {
1998                 struct btrfs_fs_devices *tmp_fs_devices;
1999
2000                 tmp_fs_devices = fs_info->fs_devices;
2001                 while (tmp_fs_devices) {
2002                         if (tmp_fs_devices->seed == fs_devices) {
2003                                 tmp_fs_devices->seed = fs_devices->seed;
2004                                 break;
2005                         }
2006                         tmp_fs_devices = tmp_fs_devices->seed;
2007                 }
2008                 fs_devices->seed = NULL;
2009                 __btrfs_close_devices(fs_devices);
2010                 free_fs_devices(fs_devices);
2011         }
2012 }
2013
2014 void btrfs_destroy_dev_replace_tgtdev(struct btrfs_fs_info *fs_info,
2015                                       struct btrfs_device *tgtdev)
2016 {
2017         struct btrfs_device *next_device;
2018
2019         mutex_lock(&uuid_mutex);
2020         WARN_ON(!tgtdev);
2021         mutex_lock(&fs_info->fs_devices->device_list_mutex);
2022
2023         btrfs_sysfs_rm_device_link(fs_info->fs_devices, tgtdev);
2024
2025         if (tgtdev->bdev) {
2026                 btrfs_scratch_superblocks(tgtdev->bdev, tgtdev->name->str);
2027                 fs_info->fs_devices->open_devices--;
2028         }
2029         fs_info->fs_devices->num_devices--;
2030
2031         next_device = list_entry(fs_info->fs_devices->devices.next,
2032                                  struct btrfs_device, dev_list);
2033         if (tgtdev->bdev == fs_info->sb->s_bdev)
2034                 fs_info->sb->s_bdev = next_device->bdev;
2035         if (tgtdev->bdev == fs_info->fs_devices->latest_bdev)
2036                 fs_info->fs_devices->latest_bdev = next_device->bdev;
2037         list_del_rcu(&tgtdev->dev_list);
2038
2039         call_rcu(&tgtdev->rcu, free_device);
2040
2041         mutex_unlock(&fs_info->fs_devices->device_list_mutex);
2042         mutex_unlock(&uuid_mutex);
2043 }
2044
2045 static int btrfs_find_device_by_path(struct btrfs_root *root, char *device_path,
2046                                      struct btrfs_device **device)
2047 {
2048         int ret = 0;
2049         struct btrfs_super_block *disk_super;
2050         u64 devid;
2051         u8 *dev_uuid;
2052         struct block_device *bdev;
2053         struct buffer_head *bh;
2054
2055         *device = NULL;
2056         ret = btrfs_get_bdev_and_sb(device_path, FMODE_READ,
2057                                     root->fs_info->bdev_holder, 0, &bdev, &bh);
2058         if (ret)
2059                 return ret;
2060         disk_super = (struct btrfs_super_block *)bh->b_data;
2061         devid = btrfs_stack_device_id(&disk_super->dev_item);
2062         dev_uuid = disk_super->dev_item.uuid;
2063         *device = btrfs_find_device(root->fs_info, devid, dev_uuid,
2064                                     disk_super->fsid);
2065         brelse(bh);
2066         if (!*device)
2067                 ret = -ENOENT;
2068         blkdev_put(bdev, FMODE_READ);
2069         return ret;
2070 }
2071
2072 int btrfs_find_device_missing_or_by_path(struct btrfs_root *root,
2073                                          char *device_path,
2074                                          struct btrfs_device **device)
2075 {
2076         *device = NULL;
2077         if (strcmp(device_path, "missing") == 0) {
2078                 struct list_head *devices;
2079                 struct btrfs_device *tmp;
2080
2081                 devices = &root->fs_info->fs_devices->devices;
2082                 /*
2083                  * It is safe to read the devices since the volume_mutex
2084                  * is held by the caller.
2085                  */
2086                 list_for_each_entry(tmp, devices, dev_list) {
2087                         if (tmp->in_fs_metadata && !tmp->bdev) {
2088                                 *device = tmp;
2089                                 break;
2090                         }
2091                 }
2092
2093                 if (!*device)
2094                         return BTRFS_ERROR_DEV_MISSING_NOT_FOUND;
2095
2096                 return 0;
2097         } else {
2098                 return btrfs_find_device_by_path(root, device_path, device);
2099         }
2100 }
2101
2102 /*
2103  * does all the dirty work required for changing file system's UUID.
2104  */
2105 static int btrfs_prepare_sprout(struct btrfs_root *root)
2106 {
2107         struct btrfs_fs_devices *fs_devices = root->fs_info->fs_devices;
2108         struct btrfs_fs_devices *old_devices;
2109         struct btrfs_fs_devices *seed_devices;
2110         struct btrfs_super_block *disk_super = root->fs_info->super_copy;
2111         struct btrfs_device *device;
2112         u64 super_flags;
2113
2114         BUG_ON(!mutex_is_locked(&uuid_mutex));
2115         if (!fs_devices->seeding)
2116                 return -EINVAL;
2117
2118         seed_devices = __alloc_fs_devices();
2119         if (IS_ERR(seed_devices))
2120                 return PTR_ERR(seed_devices);
2121
2122         old_devices = clone_fs_devices(fs_devices);
2123         if (IS_ERR(old_devices)) {
2124                 kfree(seed_devices);
2125                 return PTR_ERR(old_devices);
2126         }
2127
2128         list_add(&old_devices->list, &fs_uuids);
2129
2130         memcpy(seed_devices, fs_devices, sizeof(*seed_devices));
2131         seed_devices->opened = 1;
2132         INIT_LIST_HEAD(&seed_devices->devices);
2133         INIT_LIST_HEAD(&seed_devices->alloc_list);
2134         mutex_init(&seed_devices->device_list_mutex);
2135
2136         mutex_lock(&root->fs_info->fs_devices->device_list_mutex);
2137         list_splice_init_rcu(&fs_devices->devices, &seed_devices->devices,
2138                               synchronize_rcu);
2139         list_for_each_entry(device, &seed_devices->devices, dev_list)
2140                 device->fs_devices = seed_devices;
2141
2142         lock_chunks(root);
2143         list_splice_init(&fs_devices->alloc_list, &seed_devices->alloc_list);
2144         unlock_chunks(root);
2145
2146         fs_devices->seeding = 0;
2147         fs_devices->num_devices = 0;
2148         fs_devices->open_devices = 0;
2149         fs_devices->missing_devices = 0;
2150         fs_devices->rotating = 0;
2151         fs_devices->seed = seed_devices;
2152
2153         generate_random_uuid(fs_devices->fsid);
2154         memcpy(root->fs_info->fsid, fs_devices->fsid, BTRFS_FSID_SIZE);
2155         memcpy(disk_super->fsid, fs_devices->fsid, BTRFS_FSID_SIZE);
2156         mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
2157
2158         super_flags = btrfs_super_flags(disk_super) &
2159                       ~BTRFS_SUPER_FLAG_SEEDING;
2160         btrfs_set_super_flags(disk_super, super_flags);
2161
2162         return 0;
2163 }
2164
2165 /*
2166  * strore the expected generation for seed devices in device items.
2167  */
2168 static int btrfs_finish_sprout(struct btrfs_trans_handle *trans,
2169                                struct btrfs_root *root)
2170 {
2171         struct btrfs_path *path;
2172         struct extent_buffer *leaf;
2173         struct btrfs_dev_item *dev_item;
2174         struct btrfs_device *device;
2175         struct btrfs_key key;
2176         u8 fs_uuid[BTRFS_UUID_SIZE];
2177         u8 dev_uuid[BTRFS_UUID_SIZE];
2178         u64 devid;
2179         int ret;
2180
2181         path = btrfs_alloc_path();
2182         if (!path)
2183                 return -ENOMEM;
2184
2185         root = root->fs_info->chunk_root;
2186         key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
2187         key.offset = 0;
2188         key.type = BTRFS_DEV_ITEM_KEY;
2189
2190         while (1) {
2191                 ret = btrfs_search_slot(trans, root, &key, path, 0, 1);
2192                 if (ret < 0)
2193                         goto error;
2194
2195                 leaf = path->nodes[0];
2196 next_slot:
2197                 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
2198                         ret = btrfs_next_leaf(root, path);
2199                         if (ret > 0)
2200                                 break;
2201                         if (ret < 0)
2202                                 goto error;
2203                         leaf = path->nodes[0];
2204                         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
2205                         btrfs_release_path(path);
2206                         continue;
2207                 }
2208
2209                 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
2210                 if (key.objectid != BTRFS_DEV_ITEMS_OBJECTID ||
2211                     key.type != BTRFS_DEV_ITEM_KEY)
2212                         break;
2213
2214                 dev_item = btrfs_item_ptr(leaf, path->slots[0],
2215                                           struct btrfs_dev_item);
2216                 devid = btrfs_device_id(leaf, dev_item);
2217                 read_extent_buffer(leaf, dev_uuid, btrfs_device_uuid(dev_item),
2218                                    BTRFS_UUID_SIZE);
2219                 read_extent_buffer(leaf, fs_uuid, btrfs_device_fsid(dev_item),
2220                                    BTRFS_UUID_SIZE);
2221                 device = btrfs_find_device(root->fs_info, devid, dev_uuid,
2222                                            fs_uuid);
2223                 BUG_ON(!device); /* Logic error */
2224
2225                 if (device->fs_devices->seeding) {
2226                         btrfs_set_device_generation(leaf, dev_item,
2227                                                     device->generation);
2228                         btrfs_mark_buffer_dirty(leaf);
2229                 }
2230
2231                 path->slots[0]++;
2232                 goto next_slot;
2233         }
2234         ret = 0;
2235 error:
2236         btrfs_free_path(path);
2237         return ret;
2238 }
2239
2240 int btrfs_init_new_device(struct btrfs_root *root, char *device_path)
2241 {
2242         struct request_queue *q;
2243         struct btrfs_trans_handle *trans;
2244         struct btrfs_device *device;
2245         struct block_device *bdev;
2246         struct list_head *devices;
2247         struct super_block *sb = root->fs_info->sb;
2248         struct rcu_string *name;
2249         u64 tmp;
2250         int seeding_dev = 0;
2251         int ret = 0;
2252
2253         if ((sb->s_flags & MS_RDONLY) && !root->fs_info->fs_devices->seeding)
2254                 return -EROFS;
2255
2256         bdev = blkdev_get_by_path(device_path, FMODE_WRITE | FMODE_EXCL,
2257                                   root->fs_info->bdev_holder);
2258         if (IS_ERR(bdev))
2259                 return PTR_ERR(bdev);
2260
2261         if (root->fs_info->fs_devices->seeding) {
2262                 seeding_dev = 1;
2263                 down_write(&sb->s_umount);
2264                 mutex_lock(&uuid_mutex);
2265         }
2266
2267         filemap_write_and_wait(bdev->bd_inode->i_mapping);
2268
2269         devices = &root->fs_info->fs_devices->devices;
2270
2271         mutex_lock(&root->fs_info->fs_devices->device_list_mutex);
2272         list_for_each_entry(device, devices, dev_list) {
2273                 if (device->bdev == bdev) {
2274                         ret = -EEXIST;
2275                         mutex_unlock(
2276                                 &root->fs_info->fs_devices->device_list_mutex);
2277                         goto error;
2278                 }
2279         }
2280         mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
2281
2282         device = btrfs_alloc_device(root->fs_info, NULL, NULL);
2283         if (IS_ERR(device)) {
2284                 /* we can safely leave the fs_devices entry around */
2285                 ret = PTR_ERR(device);
2286                 goto error;
2287         }
2288
2289         name = rcu_string_strdup(device_path, GFP_NOFS);
2290         if (!name) {
2291                 kfree(device);
2292                 ret = -ENOMEM;
2293                 goto error;
2294         }
2295         rcu_assign_pointer(device->name, name);
2296
2297         trans = btrfs_start_transaction(root, 0);
2298         if (IS_ERR(trans)) {
2299                 rcu_string_free(device->name);
2300                 kfree(device);
2301                 ret = PTR_ERR(trans);
2302                 goto error;
2303         }
2304
2305         q = bdev_get_queue(bdev);
2306         if (blk_queue_discard(q))
2307                 device->can_discard = 1;
2308         device->writeable = 1;
2309         device->generation = trans->transid;
2310         device->io_width = root->sectorsize;
2311         device->io_align = root->sectorsize;
2312         device->sector_size = root->sectorsize;
2313         device->total_bytes = i_size_read(bdev->bd_inode);
2314         device->disk_total_bytes = device->total_bytes;
2315         device->commit_total_bytes = device->total_bytes;
2316         device->dev_root = root->fs_info->dev_root;
2317         device->bdev = bdev;
2318         device->in_fs_metadata = 1;
2319         device->is_tgtdev_for_dev_replace = 0;
2320         device->mode = FMODE_EXCL;
2321         device->dev_stats_valid = 1;
2322         set_blocksize(device->bdev, 4096);
2323
2324         if (seeding_dev) {
2325                 sb->s_flags &= ~MS_RDONLY;
2326                 ret = btrfs_prepare_sprout(root);
2327                 BUG_ON(ret); /* -ENOMEM */
2328         }
2329
2330         device->fs_devices = root->fs_info->fs_devices;
2331
2332         mutex_lock(&root->fs_info->fs_devices->device_list_mutex);
2333         lock_chunks(root);
2334         list_add_rcu(&device->dev_list, &root->fs_info->fs_devices->devices);
2335         list_add(&device->dev_alloc_list,
2336                  &root->fs_info->fs_devices->alloc_list);
2337         root->fs_info->fs_devices->num_devices++;
2338         root->fs_info->fs_devices->open_devices++;
2339         root->fs_info->fs_devices->rw_devices++;
2340         root->fs_info->fs_devices->total_devices++;
2341         root->fs_info->fs_devices->total_rw_bytes += device->total_bytes;
2342
2343         spin_lock(&root->fs_info->free_chunk_lock);
2344         root->fs_info->free_chunk_space += device->total_bytes;
2345         spin_unlock(&root->fs_info->free_chunk_lock);
2346
2347         if (!blk_queue_nonrot(bdev_get_queue(bdev)))
2348                 root->fs_info->fs_devices->rotating = 1;
2349
2350         tmp = btrfs_super_total_bytes(root->fs_info->super_copy);
2351         btrfs_set_super_total_bytes(root->fs_info->super_copy,
2352                                     tmp + device->total_bytes);
2353
2354         tmp = btrfs_super_num_devices(root->fs_info->super_copy);
2355         btrfs_set_super_num_devices(root->fs_info->super_copy,
2356                                     tmp + 1);
2357
2358         /* add sysfs device entry */
2359         btrfs_sysfs_add_device_link(root->fs_info->fs_devices, device);
2360
2361         /*
2362          * we've got more storage, clear any full flags on the space
2363          * infos
2364          */
2365         btrfs_clear_space_info_full(root->fs_info);
2366
2367         unlock_chunks(root);
2368         mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
2369
2370         if (seeding_dev) {
2371                 lock_chunks(root);
2372                 ret = init_first_rw_device(trans, root, device);
2373                 unlock_chunks(root);
2374                 if (ret) {
2375                         btrfs_abort_transaction(trans, root, ret);
2376                         goto error_trans;
2377                 }
2378         }
2379
2380         ret = btrfs_add_device(trans, root, device);
2381         if (ret) {
2382                 btrfs_abort_transaction(trans, root, ret);
2383                 goto error_trans;
2384         }
2385
2386         if (seeding_dev) {
2387                 char fsid_buf[BTRFS_UUID_UNPARSED_SIZE];
2388
2389                 ret = btrfs_finish_sprout(trans, root);
2390                 if (ret) {
2391                         btrfs_abort_transaction(trans, root, ret);
2392                         goto error_trans;
2393                 }
2394
2395                 /* Sprouting would change fsid of the mounted root,
2396                  * so rename the fsid on the sysfs
2397                  */
2398                 snprintf(fsid_buf, BTRFS_UUID_UNPARSED_SIZE, "%pU",
2399                                                 root->fs_info->fsid);
2400                 if (kobject_rename(&root->fs_info->fs_devices->fsid_kobj,
2401                                                                 fsid_buf))
2402                         btrfs_warn(root->fs_info,
2403                                 "sysfs: failed to create fsid for sprout");
2404         }
2405
2406         root->fs_info->num_tolerated_disk_barrier_failures =
2407                 btrfs_calc_num_tolerated_disk_barrier_failures(root->fs_info);
2408         ret = btrfs_commit_transaction(trans, root);
2409
2410         if (seeding_dev) {
2411                 mutex_unlock(&uuid_mutex);
2412                 up_write(&sb->s_umount);
2413
2414                 if (ret) /* transaction commit */
2415                         return ret;
2416
2417                 ret = btrfs_relocate_sys_chunks(root);
2418                 if (ret < 0)
2419                         btrfs_std_error(root->fs_info, ret,
2420                                     "Failed to relocate sys chunks after "
2421                                     "device initialization. This can be fixed "
2422                                     "using the \"btrfs balance\" command.");
2423                 trans = btrfs_attach_transaction(root);
2424                 if (IS_ERR(trans)) {
2425                         if (PTR_ERR(trans) == -ENOENT)
2426                                 return 0;
2427                         return PTR_ERR(trans);
2428                 }
2429                 ret = btrfs_commit_transaction(trans, root);
2430         }
2431
2432         /* Update ctime/mtime for libblkid */
2433         update_dev_time(device_path);
2434         return ret;
2435
2436 error_trans:
2437         btrfs_end_transaction(trans, root);
2438         rcu_string_free(device->name);
2439         btrfs_sysfs_rm_device_link(root->fs_info->fs_devices, device);
2440         kfree(device);
2441 error:
2442         blkdev_put(bdev, FMODE_EXCL);
2443         if (seeding_dev) {
2444                 mutex_unlock(&uuid_mutex);
2445                 up_write(&sb->s_umount);
2446         }
2447         return ret;
2448 }
2449
2450 int btrfs_init_dev_replace_tgtdev(struct btrfs_root *root, char *device_path,
2451                                   struct btrfs_device *srcdev,
2452                                   struct btrfs_device **device_out)
2453 {
2454         struct request_queue *q;
2455         struct btrfs_device *device;
2456         struct block_device *bdev;
2457         struct btrfs_fs_info *fs_info = root->fs_info;
2458         struct list_head *devices;
2459         struct rcu_string *name;
2460         u64 devid = BTRFS_DEV_REPLACE_DEVID;
2461         int ret = 0;
2462
2463         *device_out = NULL;
2464         if (fs_info->fs_devices->seeding) {
2465                 btrfs_err(fs_info, "the filesystem is a seed filesystem!");
2466                 return -EINVAL;
2467         }
2468
2469         bdev = blkdev_get_by_path(device_path, FMODE_WRITE | FMODE_EXCL,
2470                                   fs_info->bdev_holder);
2471         if (IS_ERR(bdev)) {
2472                 btrfs_err(fs_info, "target device %s is invalid!", device_path);
2473                 return PTR_ERR(bdev);
2474         }
2475
2476         filemap_write_and_wait(bdev->bd_inode->i_mapping);
2477
2478         devices = &fs_info->fs_devices->devices;
2479         list_for_each_entry(device, devices, dev_list) {
2480                 if (device->bdev == bdev) {
2481                         btrfs_err(fs_info, "target device is in the filesystem!");
2482                         ret = -EEXIST;
2483                         goto error;
2484                 }
2485         }
2486
2487
2488         if (i_size_read(bdev->bd_inode) <
2489             btrfs_device_get_total_bytes(srcdev)) {
2490                 btrfs_err(fs_info, "target device is smaller than source device!");
2491                 ret = -EINVAL;
2492                 goto error;
2493         }
2494
2495
2496         device = btrfs_alloc_device(NULL, &devid, NULL);
2497         if (IS_ERR(device)) {
2498                 ret = PTR_ERR(device);
2499                 goto error;
2500         }
2501
2502         name = rcu_string_strdup(device_path, GFP_NOFS);
2503         if (!name) {
2504                 kfree(device);
2505                 ret = -ENOMEM;
2506                 goto error;
2507         }
2508         rcu_assign_pointer(device->name, name);
2509
2510         q = bdev_get_queue(bdev);
2511         if (blk_queue_discard(q))
2512                 device->can_discard = 1;
2513         mutex_lock(&root->fs_info->fs_devices->device_list_mutex);
2514         device->writeable = 1;
2515         device->generation = 0;
2516         device->io_width = root->sectorsize;
2517         device->io_align = root->sectorsize;
2518         device->sector_size = root->sectorsize;
2519         device->total_bytes = btrfs_device_get_total_bytes(srcdev);
2520         device->disk_total_bytes = btrfs_device_get_disk_total_bytes(srcdev);
2521         device->bytes_used = btrfs_device_get_bytes_used(srcdev);
2522         ASSERT(list_empty(&srcdev->resized_list));
2523         device->commit_total_bytes = srcdev->commit_total_bytes;
2524         device->commit_bytes_used = device->bytes_used;
2525         device->dev_root = fs_info->dev_root;
2526         device->bdev = bdev;
2527         device->in_fs_metadata = 1;
2528         device->is_tgtdev_for_dev_replace = 1;
2529         device->mode = FMODE_EXCL;
2530         device->dev_stats_valid = 1;
2531         set_blocksize(device->bdev, 4096);
2532         device->fs_devices = fs_info->fs_devices;
2533         list_add(&device->dev_list, &fs_info->fs_devices->devices);
2534         fs_info->fs_devices->num_devices++;
2535         fs_info->fs_devices->open_devices++;
2536         mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
2537
2538         *device_out = device;
2539         return ret;
2540
2541 error:
2542         blkdev_put(bdev, FMODE_EXCL);
2543         return ret;
2544 }
2545
2546 void btrfs_init_dev_replace_tgtdev_for_resume(struct btrfs_fs_info *fs_info,
2547                                               struct btrfs_device *tgtdev)
2548 {
2549         WARN_ON(fs_info->fs_devices->rw_devices == 0);
2550         tgtdev->io_width = fs_info->dev_root->sectorsize;
2551         tgtdev->io_align = fs_info->dev_root->sectorsize;
2552         tgtdev->sector_size = fs_info->dev_root->sectorsize;
2553         tgtdev->dev_root = fs_info->dev_root;
2554         tgtdev->in_fs_metadata = 1;
2555 }
2556
2557 static noinline int btrfs_update_device(struct btrfs_trans_handle *trans,
2558                                         struct btrfs_device *device)
2559 {
2560         int ret;
2561         struct btrfs_path *path;
2562         struct btrfs_root *root;
2563         struct btrfs_dev_item *dev_item;
2564         struct extent_buffer *leaf;
2565         struct btrfs_key key;
2566
2567         root = device->dev_root->fs_info->chunk_root;
2568
2569         path = btrfs_alloc_path();
2570         if (!path)
2571                 return -ENOMEM;
2572
2573         key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
2574         key.type = BTRFS_DEV_ITEM_KEY;
2575         key.offset = device->devid;
2576
2577         ret = btrfs_search_slot(trans, root, &key, path, 0, 1);
2578         if (ret < 0)
2579                 goto out;
2580
2581         if (ret > 0) {
2582                 ret = -ENOENT;
2583                 goto out;
2584         }
2585
2586         leaf = path->nodes[0];
2587         dev_item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_dev_item);
2588
2589         btrfs_set_device_id(leaf, dev_item, device->devid);
2590         btrfs_set_device_type(leaf, dev_item, device->type);
2591         btrfs_set_device_io_align(leaf, dev_item, device->io_align);
2592         btrfs_set_device_io_width(leaf, dev_item, device->io_width);
2593         btrfs_set_device_sector_size(leaf, dev_item, device->sector_size);
2594         btrfs_set_device_total_bytes(leaf, dev_item,
2595                                      btrfs_device_get_disk_total_bytes(device));
2596         btrfs_set_device_bytes_used(leaf, dev_item,
2597                                     btrfs_device_get_bytes_used(device));
2598         btrfs_mark_buffer_dirty(leaf);
2599
2600 out:
2601         btrfs_free_path(path);
2602         return ret;
2603 }
2604
2605 int btrfs_grow_device(struct btrfs_trans_handle *trans,
2606                       struct btrfs_device *device, u64 new_size)
2607 {
2608         struct btrfs_super_block *super_copy =
2609                 device->dev_root->fs_info->super_copy;
2610         struct btrfs_fs_devices *fs_devices;
2611         u64 old_total;
2612         u64 diff;
2613
2614         if (!device->writeable)
2615                 return -EACCES;
2616
2617         lock_chunks(device->dev_root);
2618         old_total = btrfs_super_total_bytes(super_copy);
2619         diff = new_size - device->total_bytes;
2620
2621         if (new_size <= device->total_bytes ||
2622             device->is_tgtdev_for_dev_replace) {
2623                 unlock_chunks(device->dev_root);
2624                 return -EINVAL;
2625         }
2626
2627         fs_devices = device->dev_root->fs_info->fs_devices;
2628
2629         btrfs_set_super_total_bytes(super_copy, old_total + diff);
2630         device->fs_devices->total_rw_bytes += diff;
2631
2632         btrfs_device_set_total_bytes(device, new_size);
2633         btrfs_device_set_disk_total_bytes(device, new_size);
2634         btrfs_clear_space_info_full(device->dev_root->fs_info);
2635         if (list_empty(&device->resized_list))
2636                 list_add_tail(&device->resized_list,
2637                               &fs_devices->resized_devices);
2638         unlock_chunks(device->dev_root);
2639
2640         return btrfs_update_device(trans, device);
2641 }
2642
2643 static int btrfs_free_chunk(struct btrfs_trans_handle *trans,
2644                             struct btrfs_root *root, u64 chunk_objectid,
2645                             u64 chunk_offset)
2646 {
2647         int ret;
2648         struct btrfs_path *path;
2649         struct btrfs_key key;
2650
2651         root = root->fs_info->chunk_root;
2652         path = btrfs_alloc_path();
2653         if (!path)
2654                 return -ENOMEM;
2655
2656         key.objectid = chunk_objectid;
2657         key.offset = chunk_offset;
2658         key.type = BTRFS_CHUNK_ITEM_KEY;
2659
2660         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
2661         if (ret < 0)
2662                 goto out;
2663         else if (ret > 0) { /* Logic error or corruption */
2664                 btrfs_std_error(root->fs_info, -ENOENT,
2665                             "Failed lookup while freeing chunk.");
2666                 ret = -ENOENT;
2667                 goto out;
2668         }
2669
2670         ret = btrfs_del_item(trans, root, path);
2671         if (ret < 0)
2672                 btrfs_std_error(root->fs_info, ret,
2673                             "Failed to delete chunk item.");
2674 out:
2675         btrfs_free_path(path);
2676         return ret;
2677 }
2678
2679 static int btrfs_del_sys_chunk(struct btrfs_root *root, u64 chunk_objectid, u64
2680                         chunk_offset)
2681 {
2682         struct btrfs_super_block *super_copy = root->fs_info->super_copy;
2683         struct btrfs_disk_key *disk_key;
2684         struct btrfs_chunk *chunk;
2685         u8 *ptr;
2686         int ret = 0;
2687         u32 num_stripes;
2688         u32 array_size;
2689         u32 len = 0;
2690         u32 cur;
2691         struct btrfs_key key;
2692
2693         lock_chunks(root);
2694         array_size = btrfs_super_sys_array_size(super_copy);
2695
2696         ptr = super_copy->sys_chunk_array;
2697         cur = 0;
2698
2699         while (cur < array_size) {
2700                 disk_key = (struct btrfs_disk_key *)ptr;
2701                 btrfs_disk_key_to_cpu(&key, disk_key);
2702
2703                 len = sizeof(*disk_key);
2704
2705                 if (key.type == BTRFS_CHUNK_ITEM_KEY) {
2706                         chunk = (struct btrfs_chunk *)(ptr + len);
2707                         num_stripes = btrfs_stack_chunk_num_stripes(chunk);
2708                         len += btrfs_chunk_item_size(num_stripes);
2709                 } else {
2710                         ret = -EIO;
2711                         break;
2712                 }
2713                 if (key.objectid == chunk_objectid &&
2714                     key.offset == chunk_offset) {
2715                         memmove(ptr, ptr + len, array_size - (cur + len));
2716                         array_size -= len;
2717                         btrfs_set_super_sys_array_size(super_copy, array_size);
2718                 } else {
2719                         ptr += len;
2720                         cur += len;
2721                 }
2722         }
2723         unlock_chunks(root);
2724         return ret;
2725 }
2726
2727 int btrfs_remove_chunk(struct btrfs_trans_handle *trans,
2728                        struct btrfs_root *root, u64 chunk_offset)
2729 {
2730         struct extent_map_tree *em_tree;
2731         struct extent_map *em;
2732         struct btrfs_root *extent_root = root->fs_info->extent_root;
2733         struct map_lookup *map;
2734         u64 dev_extent_len = 0;
2735         u64 chunk_objectid = BTRFS_FIRST_CHUNK_TREE_OBJECTID;
2736         int i, ret = 0;
2737
2738         /* Just in case */
2739         root = root->fs_info->chunk_root;
2740         em_tree = &root->fs_info->mapping_tree.map_tree;
2741
2742         read_lock(&em_tree->lock);
2743         em = lookup_extent_mapping(em_tree, chunk_offset, 1);
2744         read_unlock(&em_tree->lock);
2745
2746         if (!em || em->start > chunk_offset ||
2747             em->start + em->len < chunk_offset) {
2748                 /*
2749                  * This is a logic error, but we don't want to just rely on the
2750                  * user having built with ASSERT enabled, so if ASSERT doens't
2751                  * do anything we still error out.
2752                  */
2753                 ASSERT(0);
2754                 if (em)
2755                         free_extent_map(em);
2756                 return -EINVAL;
2757         }
2758         map = (struct map_lookup *)em->bdev;
2759         lock_chunks(root->fs_info->chunk_root);
2760         check_system_chunk(trans, extent_root, map->type);
2761         unlock_chunks(root->fs_info->chunk_root);
2762
2763         for (i = 0; i < map->num_stripes; i++) {
2764                 struct btrfs_device *device = map->stripes[i].dev;
2765                 ret = btrfs_free_dev_extent(trans, device,
2766                                             map->stripes[i].physical,
2767                                             &dev_extent_len);
2768                 if (ret) {
2769                         btrfs_abort_transaction(trans, root, ret);
2770                         goto out;
2771                 }
2772
2773                 if (device->bytes_used > 0) {
2774                         lock_chunks(root);
2775                         btrfs_device_set_bytes_used(device,
2776                                         device->bytes_used - dev_extent_len);
2777                         spin_lock(&root->fs_info->free_chunk_lock);
2778                         root->fs_info->free_chunk_space += dev_extent_len;
2779                         spin_unlock(&root->fs_info->free_chunk_lock);
2780                         btrfs_clear_space_info_full(root->fs_info);
2781                         unlock_chunks(root);
2782                 }
2783
2784                 if (map->stripes[i].dev) {
2785                         ret = btrfs_update_device(trans, map->stripes[i].dev);
2786                         if (ret) {
2787                                 btrfs_abort_transaction(trans, root, ret);
2788                                 goto out;
2789                         }
2790                 }
2791         }
2792         ret = btrfs_free_chunk(trans, root, chunk_objectid, chunk_offset);
2793         if (ret) {
2794                 btrfs_abort_transaction(trans, root, ret);
2795                 goto out;
2796         }
2797
2798         trace_btrfs_chunk_free(root, map, chunk_offset, em->len);
2799
2800         if (map->type & BTRFS_BLOCK_GROUP_SYSTEM) {
2801                 ret = btrfs_del_sys_chunk(root, chunk_objectid, chunk_offset);
2802                 if (ret) {
2803                         btrfs_abort_transaction(trans, root, ret);
2804                         goto out;
2805                 }
2806         }
2807
2808         ret = btrfs_remove_block_group(trans, extent_root, chunk_offset, em);
2809         if (ret) {
2810                 btrfs_abort_transaction(trans, extent_root, ret);
2811                 goto out;
2812         }
2813
2814 out:
2815         /* once for us */
2816         free_extent_map(em);
2817         return ret;
2818 }
2819
2820 static int btrfs_relocate_chunk(struct btrfs_root *root, u64 chunk_offset)
2821 {
2822         struct btrfs_root *extent_root;
2823         struct btrfs_trans_handle *trans;
2824         int ret;
2825
2826         root = root->fs_info->chunk_root;
2827         extent_root = root->fs_info->extent_root;
2828
2829         /*
2830          * Prevent races with automatic removal of unused block groups.
2831          * After we relocate and before we remove the chunk with offset
2832          * chunk_offset, automatic removal of the block group can kick in,
2833          * resulting in a failure when calling btrfs_remove_chunk() below.
2834          *
2835          * Make sure to acquire this mutex before doing a tree search (dev
2836          * or chunk trees) to find chunks. Otherwise the cleaner kthread might
2837          * call btrfs_remove_chunk() (through btrfs_delete_unused_bgs()) after
2838          * we release the path used to search the chunk/dev tree and before
2839          * the current task acquires this mutex and calls us.
2840          */
2841         ASSERT(mutex_is_locked(&root->fs_info->delete_unused_bgs_mutex));
2842
2843         ret = btrfs_can_relocate(extent_root, chunk_offset);
2844         if (ret)
2845                 return -ENOSPC;
2846
2847         /* step one, relocate all the extents inside this chunk */
2848         btrfs_scrub_pause(root);
2849         ret = btrfs_relocate_block_group(extent_root, chunk_offset);
2850         btrfs_scrub_continue(root);
2851         if (ret)
2852                 return ret;
2853
2854         trans = btrfs_start_trans_remove_block_group(root->fs_info,
2855                                                      chunk_offset);
2856         if (IS_ERR(trans)) {
2857                 ret = PTR_ERR(trans);
2858                 btrfs_std_error(root->fs_info, ret, NULL);
2859                 return ret;
2860         }
2861
2862         /*
2863          * step two, delete the device extents and the
2864          * chunk tree entries
2865          */
2866         ret = btrfs_remove_chunk(trans, root, chunk_offset);
2867         btrfs_end_transaction(trans, root);
2868         return ret;
2869 }
2870
2871 static int btrfs_relocate_sys_chunks(struct btrfs_root *root)
2872 {
2873         struct btrfs_root *chunk_root = root->fs_info->chunk_root;
2874         struct btrfs_path *path;
2875         struct extent_buffer *leaf;
2876         struct btrfs_chunk *chunk;
2877         struct btrfs_key key;
2878         struct btrfs_key found_key;
2879         u64 chunk_type;
2880         bool retried = false;
2881         int failed = 0;
2882         int ret;
2883
2884         path = btrfs_alloc_path();
2885         if (!path)
2886                 return -ENOMEM;
2887
2888 again:
2889         key.objectid = BTRFS_FIRST_CHUNK_TREE_OBJECTID;
2890         key.offset = (u64)-1;
2891         key.type = BTRFS_CHUNK_ITEM_KEY;
2892
2893         while (1) {
2894                 mutex_lock(&root->fs_info->delete_unused_bgs_mutex);
2895                 ret = btrfs_search_slot(NULL, chunk_root, &key, path, 0, 0);
2896                 if (ret < 0) {
2897                         mutex_unlock(&root->fs_info->delete_unused_bgs_mutex);
2898                         goto error;
2899                 }
2900                 BUG_ON(ret == 0); /* Corruption */
2901
2902                 ret = btrfs_previous_item(chunk_root, path, key.objectid,
2903                                           key.type);
2904                 if (ret)
2905                         mutex_unlock(&root->fs_info->delete_unused_bgs_mutex);
2906                 if (ret < 0)
2907                         goto error;
2908                 if (ret > 0)
2909                         break;
2910
2911                 leaf = path->nodes[0];
2912                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
2913
2914                 chunk = btrfs_item_ptr(leaf, path->slots[0],
2915                                        struct btrfs_chunk);
2916                 chunk_type = btrfs_chunk_type(leaf, chunk);
2917                 btrfs_release_path(path);
2918
2919                 if (chunk_type & BTRFS_BLOCK_GROUP_SYSTEM) {
2920                         ret = btrfs_relocate_chunk(chunk_root,
2921                                                    found_key.offset);
2922                         if (ret == -ENOSPC)
2923                                 failed++;
2924                         else
2925                                 BUG_ON(ret);
2926                 }
2927                 mutex_unlock(&root->fs_info->delete_unused_bgs_mutex);
2928
2929                 if (found_key.offset == 0)
2930                         break;
2931                 key.offset = found_key.offset - 1;
2932         }
2933         ret = 0;
2934         if (failed && !retried) {
2935                 failed = 0;
2936                 retried = true;
2937                 goto again;
2938         } else if (WARN_ON(failed && retried)) {
2939                 ret = -ENOSPC;
2940         }
2941 error:
2942         btrfs_free_path(path);
2943         return ret;
2944 }
2945
2946 static int insert_balance_item(struct btrfs_root *root,
2947                                struct btrfs_balance_control *bctl)
2948 {
2949         struct btrfs_trans_handle *trans;
2950         struct btrfs_balance_item *item;
2951         struct btrfs_disk_balance_args disk_bargs;
2952         struct btrfs_path *path;
2953         struct extent_buffer *leaf;
2954         struct btrfs_key key;
2955         int ret, err;
2956
2957         path = btrfs_alloc_path();
2958         if (!path)
2959                 return -ENOMEM;
2960
2961         trans = btrfs_start_transaction(root, 0);
2962         if (IS_ERR(trans)) {
2963                 btrfs_free_path(path);
2964                 return PTR_ERR(trans);
2965         }
2966
2967         key.objectid = BTRFS_BALANCE_OBJECTID;
2968         key.type = BTRFS_BALANCE_ITEM_KEY;
2969         key.offset = 0;
2970
2971         ret = btrfs_insert_empty_item(trans, root, path, &key,
2972                                       sizeof(*item));
2973         if (ret)
2974                 goto out;
2975
2976         leaf = path->nodes[0];
2977         item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_balance_item);
2978
2979         memset_extent_buffer(leaf, 0, (unsigned long)item, sizeof(*item));
2980
2981         btrfs_cpu_balance_args_to_disk(&disk_bargs, &bctl->data);
2982         btrfs_set_balance_data(leaf, item, &disk_bargs);
2983         btrfs_cpu_balance_args_to_disk(&disk_bargs, &bctl->meta);
2984         btrfs_set_balance_meta(leaf, item, &disk_bargs);
2985         btrfs_cpu_balance_args_to_disk(&disk_bargs, &bctl->sys);
2986         btrfs_set_balance_sys(leaf, item, &disk_bargs);
2987
2988         btrfs_set_balance_flags(leaf, item, bctl->flags);
2989
2990         btrfs_mark_buffer_dirty(leaf);
2991 out:
2992         btrfs_free_path(path);
2993         err = btrfs_commit_transaction(trans, root);
2994         if (err && !ret)
2995                 ret = err;
2996         return ret;
2997 }
2998
2999 static int del_balance_item(struct btrfs_root *root)
3000 {
3001         struct btrfs_trans_handle *trans;
3002         struct btrfs_path *path;
3003         struct btrfs_key key;
3004         int ret, err;
3005
3006         path = btrfs_alloc_path();
3007         if (!path)
3008                 return -ENOMEM;
3009
3010         trans = btrfs_start_transaction(root, 0);
3011         if (IS_ERR(trans)) {
3012                 btrfs_free_path(path);
3013                 return PTR_ERR(trans);
3014         }
3015
3016         key.objectid = BTRFS_BALANCE_OBJECTID;
3017         key.type = BTRFS_BALANCE_ITEM_KEY;
3018         key.offset = 0;
3019
3020         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
3021         if (ret < 0)
3022                 goto out;
3023         if (ret > 0) {
3024                 ret = -ENOENT;
3025                 goto out;
3026         }
3027
3028         ret = btrfs_del_item(trans, root, path);
3029 out:
3030         btrfs_free_path(path);
3031         err = btrfs_commit_transaction(trans, root);
3032         if (err && !ret)
3033                 ret = err;
3034         return ret;
3035 }
3036
3037 /*
3038  * This is a heuristic used to reduce the number of chunks balanced on
3039  * resume after balance was interrupted.
3040  */
3041 static void update_balance_args(struct btrfs_balance_control *bctl)
3042 {
3043         /*
3044          * Turn on soft mode for chunk types that were being converted.
3045          */
3046         if (bctl->data.flags & BTRFS_BALANCE_ARGS_CONVERT)
3047                 bctl->data.flags |= BTRFS_BALANCE_ARGS_SOFT;
3048         if (bctl->sys.flags & BTRFS_BALANCE_ARGS_CONVERT)
3049                 bctl->sys.flags |= BTRFS_BALANCE_ARGS_SOFT;
3050         if (bctl->meta.flags & BTRFS_BALANCE_ARGS_CONVERT)
3051                 bctl->meta.flags |= BTRFS_BALANCE_ARGS_SOFT;
3052
3053         /*
3054          * Turn on usage filter if is not already used.  The idea is
3055          * that chunks that we have already balanced should be
3056          * reasonably full.  Don't do it for chunks that are being
3057          * converted - that will keep us from relocating unconverted
3058          * (albeit full) chunks.
3059          */
3060         if (!(bctl->data.flags & BTRFS_BALANCE_ARGS_USAGE) &&
3061             !(bctl->data.flags & BTRFS_BALANCE_ARGS_USAGE_RANGE) &&
3062             !(bctl->data.flags & BTRFS_BALANCE_ARGS_CONVERT)) {
3063                 bctl->data.flags |= BTRFS_BALANCE_ARGS_USAGE;
3064                 bctl->data.usage = 90;
3065         }
3066         if (!(bctl->sys.flags & BTRFS_BALANCE_ARGS_USAGE) &&
3067             !(bctl->sys.flags & BTRFS_BALANCE_ARGS_USAGE_RANGE) &&
3068             !(bctl->sys.flags & BTRFS_BALANCE_ARGS_CONVERT)) {
3069                 bctl->sys.flags |= BTRFS_BALANCE_ARGS_USAGE;
3070                 bctl->sys.usage = 90;
3071         }
3072         if (!(bctl->meta.flags & BTRFS_BALANCE_ARGS_USAGE) &&
3073             !(bctl->meta.flags & BTRFS_BALANCE_ARGS_USAGE_RANGE) &&
3074             !(bctl->meta.flags & BTRFS_BALANCE_ARGS_CONVERT)) {
3075                 bctl->meta.flags |= BTRFS_BALANCE_ARGS_USAGE;
3076                 bctl->meta.usage = 90;
3077         }
3078 }
3079
3080 /*
3081  * Should be called with both balance and volume mutexes held to
3082  * serialize other volume operations (add_dev/rm_dev/resize) with
3083  * restriper.  Same goes for unset_balance_control.
3084  */
3085 static void set_balance_control(struct btrfs_balance_control *bctl)
3086 {
3087         struct btrfs_fs_info *fs_info = bctl->fs_info;
3088
3089         BUG_ON(fs_info->balance_ctl);
3090
3091         spin_lock(&fs_info->balance_lock);
3092         fs_info->balance_ctl = bctl;
3093         spin_unlock(&fs_info->balance_lock);
3094 }
3095
3096 static void unset_balance_control(struct btrfs_fs_info *fs_info)
3097 {
3098         struct btrfs_balance_control *bctl = fs_info->balance_ctl;
3099
3100         BUG_ON(!fs_info->balance_ctl);
3101
3102         spin_lock(&fs_info->balance_lock);
3103         fs_info->balance_ctl = NULL;
3104         spin_unlock(&fs_info->balance_lock);
3105
3106         kfree(bctl);
3107 }
3108
3109 /*
3110  * Balance filters.  Return 1 if chunk should be filtered out
3111  * (should not be balanced).
3112  */
3113 static int chunk_profiles_filter(u64 chunk_type,
3114                                  struct btrfs_balance_args *bargs)
3115 {
3116         chunk_type = chunk_to_extended(chunk_type) &
3117                                 BTRFS_EXTENDED_PROFILE_MASK;
3118
3119         if (bargs->profiles & chunk_type)
3120                 return 0;
3121
3122         return 1;
3123 }
3124
3125 static int chunk_usage_range_filter(struct btrfs_fs_info *fs_info, u64 chunk_offset,
3126                               struct btrfs_balance_args *bargs)
3127 {
3128         struct btrfs_block_group_cache *cache;
3129         u64 chunk_used;
3130         u64 user_thresh_min;
3131         u64 user_thresh_max;
3132         int ret = 1;
3133
3134         cache = btrfs_lookup_block_group(fs_info, chunk_offset);
3135         chunk_used = btrfs_block_group_used(&cache->item);
3136
3137         if (bargs->usage_min == 0)
3138                 user_thresh_min = 0;
3139         else
3140                 user_thresh_min = div_factor_fine(cache->key.offset,
3141                                         bargs->usage_min);
3142
3143         if (bargs->usage_max == 0)
3144                 user_thresh_max = 1;
3145         else if (bargs->usage_max > 100)
3146                 user_thresh_max = cache->key.offset;
3147         else
3148                 user_thresh_max = div_factor_fine(cache->key.offset,
3149                                         bargs->usage_max);
3150
3151         if (user_thresh_min <= chunk_used && chunk_used < user_thresh_max)
3152                 ret = 0;
3153
3154         btrfs_put_block_group(cache);
3155         return ret;
3156 }
3157
3158 static int chunk_usage_filter(struct btrfs_fs_info *fs_info,
3159                 u64 chunk_offset, struct btrfs_balance_args *bargs)
3160 {
3161         struct btrfs_block_group_cache *cache;
3162         u64 chunk_used, user_thresh;
3163         int ret = 1;
3164
3165         cache = btrfs_lookup_block_group(fs_info, chunk_offset);
3166         chunk_used = btrfs_block_group_used(&cache->item);
3167
3168         if (bargs->usage_min == 0)
3169                 user_thresh = 1;
3170         else if (bargs->usage > 100)
3171                 user_thresh = cache->key.offset;
3172         else
3173                 user_thresh = div_factor_fine(cache->key.offset,
3174                                               bargs->usage);
3175
3176         if (chunk_used < user_thresh)
3177                 ret = 0;
3178
3179         btrfs_put_block_group(cache);
3180         return ret;
3181 }
3182
3183 static int chunk_devid_filter(struct extent_buffer *leaf,
3184                               struct btrfs_chunk *chunk,
3185                               struct btrfs_balance_args *bargs)
3186 {
3187         struct btrfs_stripe *stripe;
3188         int num_stripes = btrfs_chunk_num_stripes(leaf, chunk);
3189         int i;
3190
3191         for (i = 0; i < num_stripes; i++) {
3192                 stripe = btrfs_stripe_nr(chunk, i);
3193                 if (btrfs_stripe_devid(leaf, stripe) == bargs->devid)
3194                         return 0;
3195         }
3196
3197         return 1;
3198 }
3199
3200 /* [pstart, pend) */
3201 static int chunk_drange_filter(struct extent_buffer *leaf,
3202                                struct btrfs_chunk *chunk,
3203                                u64 chunk_offset,
3204                                struct btrfs_balance_args *bargs)
3205 {
3206         struct btrfs_stripe *stripe;
3207         int num_stripes = btrfs_chunk_num_stripes(leaf, chunk);
3208         u64 stripe_offset;
3209         u64 stripe_length;
3210         int factor;
3211         int i;
3212
3213         if (!(bargs->flags & BTRFS_BALANCE_ARGS_DEVID))
3214                 return 0;
3215
3216         if (btrfs_chunk_type(leaf, chunk) & (BTRFS_BLOCK_GROUP_DUP |
3217              BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_RAID10)) {
3218                 factor = num_stripes / 2;
3219         } else if (btrfs_chunk_type(leaf, chunk) & BTRFS_BLOCK_GROUP_RAID5) {
3220                 factor = num_stripes - 1;
3221         } else if (btrfs_chunk_type(leaf, chunk) & BTRFS_BLOCK_GROUP_RAID6) {
3222                 factor = num_stripes - 2;
3223         } else {
3224                 factor = num_stripes;
3225         }
3226
3227         for (i = 0; i < num_stripes; i++) {
3228                 stripe = btrfs_stripe_nr(chunk, i);
3229                 if (btrfs_stripe_devid(leaf, stripe) != bargs->devid)
3230                         continue;
3231
3232                 stripe_offset = btrfs_stripe_offset(leaf, stripe);
3233                 stripe_length = btrfs_chunk_length(leaf, chunk);
3234                 stripe_length = div_u64(stripe_length, factor);
3235
3236                 if (stripe_offset < bargs->pend &&
3237                     stripe_offset + stripe_length > bargs->pstart)
3238                         return 0;
3239         }
3240
3241         return 1;
3242 }
3243
3244 /* [vstart, vend) */
3245 static int chunk_vrange_filter(struct extent_buffer *leaf,
3246                                struct btrfs_chunk *chunk,
3247                                u64 chunk_offset,
3248                                struct btrfs_balance_args *bargs)
3249 {
3250         if (chunk_offset < bargs->vend &&
3251             chunk_offset + btrfs_chunk_length(leaf, chunk) > bargs->vstart)
3252                 /* at least part of the chunk is inside this vrange */
3253                 return 0;
3254
3255         return 1;
3256 }
3257
3258 static int chunk_stripes_range_filter(struct extent_buffer *leaf,
3259                                struct btrfs_chunk *chunk,
3260                                struct btrfs_balance_args *bargs)
3261 {
3262         int num_stripes = btrfs_chunk_num_stripes(leaf, chunk);
3263
3264         if (bargs->stripes_min <= num_stripes
3265                         && num_stripes <= bargs->stripes_max)
3266                 return 0;
3267
3268         return 1;
3269 }
3270
3271 static int chunk_soft_convert_filter(u64 chunk_type,
3272                                      struct btrfs_balance_args *bargs)
3273 {
3274         if (!(bargs->flags & BTRFS_BALANCE_ARGS_CONVERT))
3275                 return 0;
3276
3277         chunk_type = chunk_to_extended(chunk_type) &
3278                                 BTRFS_EXTENDED_PROFILE_MASK;
3279
3280         if (bargs->target == chunk_type)
3281                 return 1;
3282
3283         return 0;
3284 }
3285
3286 static int should_balance_chunk(struct btrfs_root *root,
3287                                 struct extent_buffer *leaf,
3288                                 struct btrfs_chunk *chunk, u64 chunk_offset)
3289 {
3290         struct btrfs_balance_control *bctl = root->fs_info->balance_ctl;
3291         struct btrfs_balance_args *bargs = NULL;
3292         u64 chunk_type = btrfs_chunk_type(leaf, chunk);
3293
3294         /* type filter */
3295         if (!((chunk_type & BTRFS_BLOCK_GROUP_TYPE_MASK) &
3296               (bctl->flags & BTRFS_BALANCE_TYPE_MASK))) {
3297                 return 0;
3298         }
3299
3300         if (chunk_type & BTRFS_BLOCK_GROUP_DATA)
3301                 bargs = &bctl->data;
3302         else if (chunk_type & BTRFS_BLOCK_GROUP_SYSTEM)
3303                 bargs = &bctl->sys;
3304         else if (chunk_type & BTRFS_BLOCK_GROUP_METADATA)
3305                 bargs = &bctl->meta;
3306
3307         /* profiles filter */
3308         if ((bargs->flags & BTRFS_BALANCE_ARGS_PROFILES) &&
3309             chunk_profiles_filter(chunk_type, bargs)) {
3310                 return 0;
3311         }
3312
3313         /* usage filter */
3314         if ((bargs->flags & BTRFS_BALANCE_ARGS_USAGE) &&
3315             chunk_usage_filter(bctl->fs_info, chunk_offset, bargs)) {
3316                 return 0;
3317         } else if ((bargs->flags & BTRFS_BALANCE_ARGS_USAGE_RANGE) &&
3318             chunk_usage_range_filter(bctl->fs_info, chunk_offset, bargs)) {
3319                 return 0;
3320         }
3321
3322         /* devid filter */
3323         if ((bargs->flags & BTRFS_BALANCE_ARGS_DEVID) &&
3324             chunk_devid_filter(leaf, chunk, bargs)) {
3325                 return 0;
3326         }
3327
3328         /* drange filter, makes sense only with devid filter */
3329         if ((bargs->flags & BTRFS_BALANCE_ARGS_DRANGE) &&
3330             chunk_drange_filter(leaf, chunk, chunk_offset, bargs)) {
3331                 return 0;
3332         }
3333
3334         /* vrange filter */
3335         if ((bargs->flags & BTRFS_BALANCE_ARGS_VRANGE) &&
3336             chunk_vrange_filter(leaf, chunk, chunk_offset, bargs)) {
3337                 return 0;
3338         }
3339
3340         /* stripes filter */
3341         if ((bargs->flags & BTRFS_BALANCE_ARGS_STRIPES_RANGE) &&
3342             chunk_stripes_range_filter(leaf, chunk, bargs)) {
3343                 return 0;
3344         }
3345
3346         /* soft profile changing mode */
3347         if ((bargs->flags & BTRFS_BALANCE_ARGS_SOFT) &&
3348             chunk_soft_convert_filter(chunk_type, bargs)) {
3349                 return 0;
3350         }
3351
3352         /*
3353          * limited by count, must be the last filter
3354          */
3355         if ((bargs->flags & BTRFS_BALANCE_ARGS_LIMIT)) {
3356                 if (bargs->limit == 0)
3357                         return 0;
3358                 else
3359                         bargs->limit--;
3360         } else if ((bargs->flags & BTRFS_BALANCE_ARGS_LIMIT_RANGE)) {
3361                 /*
3362                  * Same logic as the 'limit' filter; the minimum cannot be
3363                  * determined here because we do not have the global informatoin
3364                  * about the count of all chunks that satisfy the filters.
3365                  */
3366                 if (bargs->limit_max == 0)
3367                         return 0;
3368                 else
3369                         bargs->limit_max--;
3370         }
3371
3372         return 1;
3373 }
3374
3375 static int __btrfs_balance(struct btrfs_fs_info *fs_info)
3376 {
3377         struct btrfs_balance_control *bctl = fs_info->balance_ctl;
3378         struct btrfs_root *chunk_root = fs_info->chunk_root;
3379         struct btrfs_root *dev_root = fs_info->dev_root;
3380         struct list_head *devices;
3381         struct btrfs_device *device;
3382         u64 old_size;
3383         u64 size_to_free;
3384         u64 chunk_type;
3385         struct btrfs_chunk *chunk;
3386         struct btrfs_path *path;
3387         struct btrfs_key key;
3388         struct btrfs_key found_key;
3389         struct btrfs_trans_handle *trans;
3390         struct extent_buffer *leaf;
3391         int slot;
3392         int ret;
3393         int enospc_errors = 0;
3394         bool counting = true;
3395         /* The single value limit and min/max limits use the same bytes in the */
3396         u64 limit_data = bctl->data.limit;
3397         u64 limit_meta = bctl->meta.limit;
3398         u64 limit_sys = bctl->sys.limit;
3399         u32 count_data = 0;
3400         u32 count_meta = 0;
3401         u32 count_sys = 0;
3402         int chunk_reserved = 0;
3403
3404         /* step one make some room on all the devices */
3405         devices = &fs_info->fs_devices->devices;
3406         list_for_each_entry(device, devices, dev_list) {
3407                 old_size = btrfs_device_get_total_bytes(device);
3408                 size_to_free = div_factor(old_size, 1);
3409                 size_to_free = min(size_to_free, (u64)1 * 1024 * 1024);
3410                 if (!device->writeable ||
3411                     btrfs_device_get_total_bytes(device) -
3412                     btrfs_device_get_bytes_used(device) > size_to_free ||
3413                     device->is_tgtdev_for_dev_replace)
3414                         continue;
3415
3416                 ret = btrfs_shrink_device(device, old_size - size_to_free);
3417                 if (ret == -ENOSPC)
3418                         break;
3419                 BUG_ON(ret);
3420
3421                 trans = btrfs_start_transaction(dev_root, 0);
3422                 BUG_ON(IS_ERR(trans));
3423
3424                 ret = btrfs_grow_device(trans, device, old_size);
3425                 BUG_ON(ret);
3426
3427                 btrfs_end_transaction(trans, dev_root);
3428         }
3429
3430         /* step two, relocate all the chunks */
3431         path = btrfs_alloc_path();
3432         if (!path) {
3433                 ret = -ENOMEM;
3434                 goto error;
3435         }
3436
3437         /* zero out stat counters */
3438         spin_lock(&fs_info->balance_lock);
3439         memset(&bctl->stat, 0, sizeof(bctl->stat));
3440         spin_unlock(&fs_info->balance_lock);
3441 again:
3442         if (!counting) {
3443                 /*
3444                  * The single value limit and min/max limits use the same bytes
3445                  * in the
3446                  */
3447                 bctl->data.limit = limit_data;
3448                 bctl->meta.limit = limit_meta;
3449                 bctl->sys.limit = limit_sys;
3450         }
3451         key.objectid = BTRFS_FIRST_CHUNK_TREE_OBJECTID;
3452         key.offset = (u64)-1;
3453         key.type = BTRFS_CHUNK_ITEM_KEY;
3454
3455         while (1) {
3456                 if ((!counting && atomic_read(&fs_info->balance_pause_req)) ||
3457                     atomic_read(&fs_info->balance_cancel_req)) {
3458                         ret = -ECANCELED;
3459                         goto error;
3460                 }
3461
3462                 mutex_lock(&fs_info->delete_unused_bgs_mutex);
3463                 ret = btrfs_search_slot(NULL, chunk_root, &key, path, 0, 0);
3464                 if (ret < 0) {
3465                         mutex_unlock(&fs_info->delete_unused_bgs_mutex);
3466                         goto error;
3467                 }
3468
3469                 /*
3470                  * this shouldn't happen, it means the last relocate
3471                  * failed
3472                  */
3473                 if (ret == 0)
3474                         BUG(); /* FIXME break ? */
3475
3476                 ret = btrfs_previous_item(chunk_root, path, 0,
3477                                           BTRFS_CHUNK_ITEM_KEY);
3478                 if (ret) {
3479                         mutex_unlock(&fs_info->delete_unused_bgs_mutex);
3480                         ret = 0;
3481                         break;
3482                 }
3483
3484                 leaf = path->nodes[0];
3485                 slot = path->slots[0];
3486                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
3487
3488                 if (found_key.objectid != key.objectid) {
3489                         mutex_unlock(&fs_info->delete_unused_bgs_mutex);
3490                         break;
3491                 }
3492
3493                 chunk = btrfs_item_ptr(leaf, slot, struct btrfs_chunk);
3494                 chunk_type = btrfs_chunk_type(leaf, chunk);
3495
3496                 if (!counting) {
3497                         spin_lock(&fs_info->balance_lock);
3498                         bctl->stat.considered++;
3499                         spin_unlock(&fs_info->balance_lock);
3500                 }
3501
3502                 ret = should_balance_chunk(chunk_root, leaf, chunk,
3503                                            found_key.offset);
3504
3505                 btrfs_release_path(path);
3506                 if (!ret) {
3507                         mutex_unlock(&fs_info->delete_unused_bgs_mutex);
3508                         goto loop;
3509                 }
3510
3511                 if (counting) {
3512                         mutex_unlock(&fs_info->delete_unused_bgs_mutex);
3513                         spin_lock(&fs_info->balance_lock);
3514                         bctl->stat.expected++;
3515                         spin_unlock(&fs_info->balance_lock);
3516
3517                         if (chunk_type & BTRFS_BLOCK_GROUP_DATA)
3518                                 count_data++;
3519                         else if (chunk_type & BTRFS_BLOCK_GROUP_SYSTEM)
3520                                 count_sys++;
3521                         else if (chunk_type & BTRFS_BLOCK_GROUP_METADATA)
3522                                 count_meta++;
3523
3524                         goto loop;
3525                 }
3526
3527                 /*
3528                  * Apply limit_min filter, no need to check if the LIMITS
3529                  * filter is used, limit_min is 0 by default
3530                  */
3531                 if (((chunk_type & BTRFS_BLOCK_GROUP_DATA) &&
3532                                         count_data < bctl->data.limit_min)
3533                                 || ((chunk_type & BTRFS_BLOCK_GROUP_METADATA) &&
3534                                         count_meta < bctl->meta.limit_min)
3535                                 || ((chunk_type & BTRFS_BLOCK_GROUP_SYSTEM) &&
3536                                         count_sys < bctl->sys.limit_min)) {
3537                         mutex_unlock(&fs_info->delete_unused_bgs_mutex);
3538                         goto loop;
3539                 }
3540
3541                 if ((chunk_type & BTRFS_BLOCK_GROUP_DATA) && !chunk_reserved) {
3542                         trans = btrfs_start_transaction(chunk_root, 0);
3543                         if (IS_ERR(trans)) {
3544                                 mutex_unlock(&fs_info->delete_unused_bgs_mutex);
3545                                 ret = PTR_ERR(trans);
3546                                 goto error;
3547                         }
3548
3549                         ret = btrfs_force_chunk_alloc(trans, chunk_root,
3550                                                       BTRFS_BLOCK_GROUP_DATA);
3551                         if (ret < 0) {
3552                                 mutex_unlock(&fs_info->delete_unused_bgs_mutex);
3553                                 goto error;
3554                         }
3555
3556                         btrfs_end_transaction(trans, chunk_root);
3557                         chunk_reserved = 1;
3558                 }
3559
3560                 ret = btrfs_relocate_chunk(chunk_root,
3561                                            found_key.offset);
3562                 mutex_unlock(&fs_info->delete_unused_bgs_mutex);
3563                 if (ret && ret != -ENOSPC)
3564                         goto error;
3565                 if (ret == -ENOSPC) {
3566                         enospc_errors++;
3567                 } else {
3568                         spin_lock(&fs_info->balance_lock);
3569                         bctl->stat.completed++;
3570                         spin_unlock(&fs_info->balance_lock);
3571                 }
3572 loop:
3573                 if (found_key.offset == 0)
3574                         break;
3575                 key.offset = found_key.offset - 1;
3576         }
3577
3578         if (counting) {
3579                 btrfs_release_path(path);
3580                 counting = false;
3581                 goto again;
3582         }
3583 error:
3584         btrfs_free_path(path);
3585         if (enospc_errors) {
3586                 btrfs_info(fs_info, "%d enospc errors during balance",
3587                        enospc_errors);
3588                 if (!ret)
3589                         ret = -ENOSPC;
3590         }
3591
3592         return ret;
3593 }
3594
3595 /**
3596  * alloc_profile_is_valid - see if a given profile is valid and reduced
3597  * @flags: profile to validate
3598  * @extended: if true @flags is treated as an extended profile
3599  */
3600 static int alloc_profile_is_valid(u64 flags, int extended)
3601 {
3602         u64 mask = (extended ? BTRFS_EXTENDED_PROFILE_MASK :
3603                                BTRFS_BLOCK_GROUP_PROFILE_MASK);
3604
3605         flags &= ~BTRFS_BLOCK_GROUP_TYPE_MASK;
3606
3607         /* 1) check that all other bits are zeroed */
3608         if (flags & ~mask)
3609                 return 0;
3610
3611         /* 2) see if profile is reduced */
3612         if (flags == 0)
3613                 return !extended; /* "0" is valid for usual profiles */
3614
3615         /* true if exactly one bit set */
3616         return (flags & (flags - 1)) == 0;
3617 }
3618
3619 static inline int balance_need_close(struct btrfs_fs_info *fs_info)
3620 {
3621         /* cancel requested || normal exit path */
3622         return atomic_read(&fs_info->balance_cancel_req) ||
3623                 (atomic_read(&fs_info->balance_pause_req) == 0 &&
3624                  atomic_read(&fs_info->balance_cancel_req) == 0);
3625 }
3626
3627 static void __cancel_balance(struct btrfs_fs_info *fs_info)
3628 {
3629         int ret;
3630
3631         unset_balance_control(fs_info);
3632         ret = del_balance_item(fs_info->tree_root);
3633         if (ret)
3634                 btrfs_std_error(fs_info, ret, NULL);
3635
3636         atomic_set(&fs_info->mutually_exclusive_operation_running, 0);
3637 }
3638
3639 /* Non-zero return value signifies invalidity */
3640 static inline int validate_convert_profile(struct btrfs_balance_args *bctl_arg,
3641                 u64 allowed)
3642 {
3643         return ((bctl_arg->flags & BTRFS_BALANCE_ARGS_CONVERT) &&
3644                 (!alloc_profile_is_valid(bctl_arg->target, 1) ||
3645                  (bctl_arg->target & ~allowed)));
3646 }
3647
3648 /*
3649  * Should be called with both balance and volume mutexes held
3650  */
3651 int btrfs_balance(struct btrfs_balance_control *bctl,
3652                   struct btrfs_ioctl_balance_args *bargs)
3653 {
3654         struct btrfs_fs_info *fs_info = bctl->fs_info;
3655         u64 allowed;
3656         int mixed = 0;
3657         int ret;
3658         u64 num_devices;
3659         unsigned seq;
3660
3661         if (btrfs_fs_closing(fs_info) ||
3662             atomic_read(&fs_info->balance_pause_req) ||
3663             atomic_read(&fs_info->balance_cancel_req)) {
3664                 ret = -EINVAL;
3665                 goto out;
3666         }
3667
3668         allowed = btrfs_super_incompat_flags(fs_info->super_copy);
3669         if (allowed & BTRFS_FEATURE_INCOMPAT_MIXED_GROUPS)
3670                 mixed = 1;
3671
3672         /*
3673          * In case of mixed groups both data and meta should be picked,
3674          * and identical options should be given for both of them.
3675          */
3676         allowed = BTRFS_BALANCE_DATA | BTRFS_BALANCE_METADATA;
3677         if (mixed && (bctl->flags & allowed)) {
3678                 if (!(bctl->flags & BTRFS_BALANCE_DATA) ||
3679                     !(bctl->flags & BTRFS_BALANCE_METADATA) ||
3680                     memcmp(&bctl->data, &bctl->meta, sizeof(bctl->data))) {
3681                         btrfs_err(fs_info, "with mixed groups data and "
3682                                    "metadata balance options must be the same");
3683                         ret = -EINVAL;
3684                         goto out;
3685                 }
3686         }
3687
3688         num_devices = fs_info->fs_devices->num_devices;
3689         btrfs_dev_replace_lock(&fs_info->dev_replace);
3690         if (btrfs_dev_replace_is_ongoing(&fs_info->dev_replace)) {
3691                 BUG_ON(num_devices < 1);
3692                 num_devices--;
3693         }
3694         btrfs_dev_replace_unlock(&fs_info->dev_replace);
3695         allowed = BTRFS_AVAIL_ALLOC_BIT_SINGLE;
3696         if (num_devices == 1)
3697                 allowed |= BTRFS_BLOCK_GROUP_DUP;
3698         else if (num_devices > 1)
3699                 allowed |= (BTRFS_BLOCK_GROUP_RAID0 | BTRFS_BLOCK_GROUP_RAID1);
3700         if (num_devices > 2)
3701                 allowed |= BTRFS_BLOCK_GROUP_RAID5;
3702         if (num_devices > 3)
3703                 allowed |= (BTRFS_BLOCK_GROUP_RAID10 |
3704                             BTRFS_BLOCK_GROUP_RAID6);
3705         if (validate_convert_profile(&bctl->data, allowed)) {
3706                 btrfs_err(fs_info, "unable to start balance with target "
3707                            "data profile %llu",
3708                        bctl->data.target);
3709                 ret = -EINVAL;
3710                 goto out;
3711         }
3712         if (validate_convert_profile(&bctl->meta, allowed)) {
3713                 btrfs_err(fs_info,
3714                            "unable to start balance with target metadata profile %llu",
3715                        bctl->meta.target);
3716                 ret = -EINVAL;
3717                 goto out;
3718         }
3719         if (validate_convert_profile(&bctl->sys, allowed)) {
3720                 btrfs_err(fs_info,
3721                            "unable to start balance with target system profile %llu",
3722                        bctl->sys.target);
3723                 ret = -EINVAL;
3724                 goto out;
3725         }
3726
3727         /* allow dup'ed data chunks only in mixed mode */
3728         if (!mixed && (bctl->data.flags & BTRFS_BALANCE_ARGS_CONVERT) &&
3729             (bctl->data.target & BTRFS_BLOCK_GROUP_DUP)) {
3730                 btrfs_err(fs_info, "dup for data is not allowed");
3731                 ret = -EINVAL;
3732                 goto out;
3733         }
3734
3735         /* allow to reduce meta or sys integrity only if force set */
3736         allowed = BTRFS_BLOCK_GROUP_DUP | BTRFS_BLOCK_GROUP_RAID1 |
3737                         BTRFS_BLOCK_GROUP_RAID10 |
3738                         BTRFS_BLOCK_GROUP_RAID5 |
3739                         BTRFS_BLOCK_GROUP_RAID6;
3740         do {
3741                 seq = read_seqbegin(&fs_info->profiles_lock);
3742
3743                 if (((bctl->sys.flags & BTRFS_BALANCE_ARGS_CONVERT) &&
3744                      (fs_info->avail_system_alloc_bits & allowed) &&
3745                      !(bctl->sys.target & allowed)) ||
3746                     ((bctl->meta.flags & BTRFS_BALANCE_ARGS_CONVERT) &&
3747                      (fs_info->avail_metadata_alloc_bits & allowed) &&
3748                      !(bctl->meta.target & allowed))) {
3749                         if (bctl->flags & BTRFS_BALANCE_FORCE) {
3750                                 btrfs_info(fs_info, "force reducing metadata integrity");
3751                         } else {
3752                                 btrfs_err(fs_info, "balance will reduce metadata "
3753                                            "integrity, use force if you want this");
3754                                 ret = -EINVAL;
3755                                 goto out;
3756                         }
3757                 }
3758         } while (read_seqretry(&fs_info->profiles_lock, seq));
3759
3760         if (bctl->sys.flags & BTRFS_BALANCE_ARGS_CONVERT) {
3761                 fs_info->num_tolerated_disk_barrier_failures = min(
3762                         btrfs_calc_num_tolerated_disk_barrier_failures(fs_info),
3763                         btrfs_get_num_tolerated_disk_barrier_failures(
3764                                 bctl->sys.target));
3765         }
3766
3767         ret = insert_balance_item(fs_info->tree_root, bctl);
3768         if (ret && ret != -EEXIST)
3769                 goto out;
3770
3771         if (!(bctl->flags & BTRFS_BALANCE_RESUME)) {
3772                 BUG_ON(ret == -EEXIST);
3773                 set_balance_control(bctl);
3774         } else {
3775                 BUG_ON(ret != -EEXIST);
3776                 spin_lock(&fs_info->balance_lock);
3777                 update_balance_args(bctl);
3778                 spin_unlock(&fs_info->balance_lock);
3779         }
3780
3781         atomic_inc(&fs_info->balance_running);
3782         mutex_unlock(&fs_info->balance_mutex);
3783
3784         ret = __btrfs_balance(fs_info);
3785
3786         mutex_lock(&fs_info->balance_mutex);
3787         atomic_dec(&fs_info->balance_running);
3788
3789         if (bctl->sys.flags & BTRFS_BALANCE_ARGS_CONVERT) {
3790                 fs_info->num_tolerated_disk_barrier_failures =
3791                         btrfs_calc_num_tolerated_disk_barrier_failures(fs_info);
3792         }
3793
3794         if (bargs) {
3795                 memset(bargs, 0, sizeof(*bargs));
3796                 update_ioctl_balance_args(fs_info, 0, bargs);
3797         }
3798
3799         if ((ret && ret != -ECANCELED && ret != -ENOSPC) ||
3800             balance_need_close(fs_info)) {
3801                 __cancel_balance(fs_info);
3802         }
3803
3804         wake_up(&fs_info->balance_wait_q);
3805
3806         return ret;
3807 out:
3808         if (bctl->flags & BTRFS_BALANCE_RESUME)
3809                 __cancel_balance(fs_info);
3810         else {
3811                 kfree(bctl);
3812                 atomic_set(&fs_info->mutually_exclusive_operation_running, 0);
3813         }
3814         return ret;
3815 }
3816
3817 static int balance_kthread(void *data)
3818 {
3819         struct btrfs_fs_info *fs_info = data;
3820         int ret = 0;
3821
3822         mutex_lock(&fs_info->volume_mutex);
3823         mutex_lock(&fs_info->balance_mutex);
3824
3825         if (fs_info->balance_ctl) {
3826                 btrfs_info(fs_info, "continuing balance");
3827                 ret = btrfs_balance(fs_info->balance_ctl, NULL);
3828         }
3829
3830         mutex_unlock(&fs_info->balance_mutex);
3831         mutex_unlock(&fs_info->volume_mutex);
3832
3833         return ret;
3834 }
3835
3836 int btrfs_resume_balance_async(struct btrfs_fs_info *fs_info)
3837 {
3838         struct task_struct *tsk;
3839
3840         spin_lock(&fs_info->balance_lock);
3841         if (!fs_info->balance_ctl) {
3842                 spin_unlock(&fs_info->balance_lock);
3843                 return 0;
3844         }
3845         spin_unlock(&fs_info->balance_lock);
3846
3847         if (btrfs_test_opt(fs_info->tree_root, SKIP_BALANCE)) {
3848                 btrfs_info(fs_info, "force skipping balance");
3849                 return 0;
3850         }
3851
3852         tsk = kthread_run(balance_kthread, fs_info, "btrfs-balance");
3853         return PTR_ERR_OR_ZERO(tsk);
3854 }
3855
3856 int btrfs_recover_balance(struct btrfs_fs_info *fs_info)
3857 {
3858         struct btrfs_balance_control *bctl;
3859         struct btrfs_balance_item *item;
3860         struct btrfs_disk_balance_args disk_bargs;
3861         struct btrfs_path *path;
3862         struct extent_buffer *leaf;
3863         struct btrfs_key key;
3864         int ret;
3865
3866         path = btrfs_alloc_path();
3867         if (!path)
3868                 return -ENOMEM;
3869
3870         key.objectid = BTRFS_BALANCE_OBJECTID;
3871         key.type = BTRFS_BALANCE_ITEM_KEY;
3872         key.offset = 0;
3873
3874         ret = btrfs_search_slot(NULL, fs_info->tree_root, &key, path, 0, 0);
3875         if (ret < 0)
3876                 goto out;
3877         if (ret > 0) { /* ret = -ENOENT; */
3878                 ret = 0;
3879                 goto out;
3880         }
3881
3882         bctl = kzalloc(sizeof(*bctl), GFP_NOFS);
3883         if (!bctl) {
3884                 ret = -ENOMEM;
3885                 goto out;
3886         }
3887
3888         leaf = path->nodes[0];
3889         item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_balance_item);
3890
3891         bctl->fs_info = fs_info;
3892         bctl->flags = btrfs_balance_flags(leaf, item);
3893         bctl->flags |= BTRFS_BALANCE_RESUME;
3894
3895         btrfs_balance_data(leaf, item, &disk_bargs);
3896         btrfs_disk_balance_args_to_cpu(&bctl->data, &disk_bargs);
3897         btrfs_balance_meta(leaf, item, &disk_bargs);
3898         btrfs_disk_balance_args_to_cpu(&bctl->meta, &disk_bargs);
3899         btrfs_balance_sys(leaf, item, &disk_bargs);
3900         btrfs_disk_balance_args_to_cpu(&bctl->sys, &disk_bargs);
3901
3902         WARN_ON(atomic_xchg(&fs_info->mutually_exclusive_operation_running, 1));
3903
3904         mutex_lock(&fs_info->volume_mutex);
3905         mutex_lock(&fs_info->balance_mutex);
3906
3907         set_balance_control(bctl);
3908
3909         mutex_unlock(&fs_info->balance_mutex);
3910         mutex_unlock(&fs_info->volume_mutex);
3911 out:
3912         btrfs_free_path(path);
3913         return ret;
3914 }
3915
3916 int btrfs_pause_balance(struct btrfs_fs_info *fs_info)
3917 {
3918         int ret = 0;
3919
3920         mutex_lock(&fs_info->balance_mutex);
3921         if (!fs_info->balance_ctl) {
3922                 mutex_unlock(&fs_info->balance_mutex);
3923                 return -ENOTCONN;
3924         }
3925
3926         if (atomic_read(&fs_info->balance_running)) {
3927                 atomic_inc(&fs_info->balance_pause_req);
3928                 mutex_unlock(&fs_info->balance_mutex);
3929
3930                 wait_event(fs_info->balance_wait_q,
3931                            atomic_read(&fs_info->balance_running) == 0);
3932
3933                 mutex_lock(&fs_info->balance_mutex);
3934                 /* we are good with balance_ctl ripped off from under us */
3935                 BUG_ON(atomic_read(&fs_info->balance_running));
3936                 atomic_dec(&fs_info->balance_pause_req);
3937         } else {
3938                 ret = -ENOTCONN;
3939         }
3940
3941         mutex_unlock(&fs_info->balance_mutex);
3942         return ret;
3943 }
3944
3945 int btrfs_cancel_balance(struct btrfs_fs_info *fs_info)
3946 {
3947         if (fs_info->sb->s_flags & MS_RDONLY)
3948                 return -EROFS;
3949
3950         mutex_lock(&fs_info->balance_mutex);
3951         if (!fs_info->balance_ctl) {
3952                 mutex_unlock(&fs_info->balance_mutex);
3953                 return -ENOTCONN;
3954         }
3955
3956         atomic_inc(&fs_info->balance_cancel_req);
3957         /*
3958          * if we are running just wait and return, balance item is
3959          * deleted in btrfs_balance in this case
3960          */
3961         if (atomic_read(&fs_info->balance_running)) {
3962                 mutex_unlock(&fs_info->balance_mutex);
3963                 wait_event(fs_info->balance_wait_q,
3964                            atomic_read(&fs_info->balance_running) == 0);
3965                 mutex_lock(&fs_info->balance_mutex);
3966         } else {
3967                 /* __cancel_balance needs volume_mutex */
3968                 mutex_unlock(&fs_info->balance_mutex);
3969                 mutex_lock(&fs_info->volume_mutex);
3970                 mutex_lock(&fs_info->balance_mutex);
3971
3972                 if (fs_info->balance_ctl)
3973                         __cancel_balance(fs_info);
3974
3975                 mutex_unlock(&fs_info->volume_mutex);
3976         }
3977
3978         BUG_ON(fs_info->balance_ctl || atomic_read(&fs_info->balance_running));
3979         atomic_dec(&fs_info->balance_cancel_req);
3980         mutex_unlock(&fs_info->balance_mutex);
3981         return 0;
3982 }
3983
3984 static int btrfs_uuid_scan_kthread(void *data)
3985 {
3986         struct btrfs_fs_info *fs_info = data;
3987         struct btrfs_root *root = fs_info->tree_root;
3988         struct btrfs_key key;
3989         struct btrfs_key max_key;
3990         struct btrfs_path *path = NULL;
3991         int ret = 0;
3992         struct extent_buffer *eb;
3993         int slot;
3994         struct btrfs_root_item root_item;
3995         u32 item_size;
3996         struct btrfs_trans_handle *trans = NULL;
3997
3998         path = btrfs_alloc_path();
3999         if (!path) {
4000                 ret = -ENOMEM;
4001                 goto out;
4002         }
4003
4004         key.objectid = 0;
4005         key.type = BTRFS_ROOT_ITEM_KEY;
4006         key.offset = 0;
4007
4008         max_key.objectid = (u64)-1;
4009         max_key.type = BTRFS_ROOT_ITEM_KEY;
4010         max_key.offset = (u64)-1;
4011
4012         while (1) {
4013                 ret = btrfs_search_forward(root, &key, path, 0);
4014                 if (ret) {
4015                         if (ret > 0)
4016                                 ret = 0;
4017                         break;
4018                 }
4019
4020                 if (key.type != BTRFS_ROOT_ITEM_KEY ||
4021                     (key.objectid < BTRFS_FIRST_FREE_OBJECTID &&
4022                      key.objectid != BTRFS_FS_TREE_OBJECTID) ||
4023                     key.objectid > BTRFS_LAST_FREE_OBJECTID)
4024                         goto skip;
4025
4026                 eb = path->nodes[0];
4027                 slot = path->slots[0];
4028                 item_size = btrfs_item_size_nr(eb, slot);
4029                 if (item_size < sizeof(root_item))
4030                         goto skip;
4031
4032                 read_extent_buffer(eb, &root_item,
4033                                    btrfs_item_ptr_offset(eb, slot),
4034                                    (int)sizeof(root_item));
4035                 if (btrfs_root_refs(&root_item) == 0)
4036                         goto skip;
4037
4038                 if (!btrfs_is_empty_uuid(root_item.uuid) ||
4039                     !btrfs_is_empty_uuid(root_item.received_uuid)) {
4040                         if (trans)
4041                                 goto update_tree;
4042
4043                         btrfs_release_path(path);
4044                         /*
4045                          * 1 - subvol uuid item
4046                          * 1 - received_subvol uuid item
4047                          */
4048                         trans = btrfs_start_transaction(fs_info->uuid_root, 2);
4049                         if (IS_ERR(trans)) {
4050                                 ret = PTR_ERR(trans);
4051                                 break;
4052                         }
4053                         continue;
4054                 } else {
4055                         goto skip;
4056                 }
4057 update_tree:
4058                 if (!btrfs_is_empty_uuid(root_item.uuid)) {
4059                         ret = btrfs_uuid_tree_add(trans, fs_info->uuid_root,
4060                                                   root_item.uuid,
4061                                                   BTRFS_UUID_KEY_SUBVOL,
4062                                                   key.objectid);
4063                         if (ret < 0) {
4064                                 btrfs_warn(fs_info, "uuid_tree_add failed %d",
4065                                         ret);
4066                                 break;
4067                         }
4068                 }
4069
4070                 if (!btrfs_is_empty_uuid(root_item.received_uuid)) {
4071                         ret = btrfs_uuid_tree_add(trans, fs_info->uuid_root,
4072                                                   root_item.received_uuid,
4073                                                  BTRFS_UUID_KEY_RECEIVED_SUBVOL,
4074                                                   key.objectid);
4075                         if (ret < 0) {
4076                                 btrfs_warn(fs_info, "uuid_tree_add failed %d",
4077                                         ret);
4078                                 break;
4079                         }
4080                 }
4081
4082 skip:
4083                 if (trans) {
4084                         ret = btrfs_end_transaction(trans, fs_info->uuid_root);
4085                         trans = NULL;
4086                         if (ret)
4087                                 break;
4088                 }
4089
4090                 btrfs_release_path(path);
4091                 if (key.offset < (u64)-1) {
4092                         key.offset++;
4093                 } else if (key.type < BTRFS_ROOT_ITEM_KEY) {
4094                         key.offset = 0;
4095                         key.type = BTRFS_ROOT_ITEM_KEY;
4096                 } else if (key.objectid < (u64)-1) {
4097                         key.offset = 0;
4098                         key.type = BTRFS_ROOT_ITEM_KEY;
4099                         key.objectid++;
4100                 } else {
4101                         break;
4102                 }
4103                 cond_resched();
4104         }
4105
4106 out:
4107         btrfs_free_path(path);
4108         if (trans && !IS_ERR(trans))
4109                 btrfs_end_transaction(trans, fs_info->uuid_root);
4110         if (ret)
4111                 btrfs_warn(fs_info, "btrfs_uuid_scan_kthread failed %d", ret);
4112         else
4113                 fs_info->update_uuid_tree_gen = 1;
4114         up(&fs_info->uuid_tree_rescan_sem);
4115         return 0;
4116 }
4117
4118 /*
4119  * Callback for btrfs_uuid_tree_iterate().
4120  * returns:
4121  * 0    check succeeded, the entry is not outdated.
4122  * < 0  if an error occured.
4123  * > 0  if the check failed, which means the caller shall remove the entry.
4124  */
4125 static int btrfs_check_uuid_tree_entry(struct btrfs_fs_info *fs_info,
4126                                        u8 *uuid, u8 type, u64 subid)
4127 {
4128         struct btrfs_key key;
4129         int ret = 0;
4130         struct btrfs_root *subvol_root;
4131
4132         if (type != BTRFS_UUID_KEY_SUBVOL &&
4133             type != BTRFS_UUID_KEY_RECEIVED_SUBVOL)
4134                 goto out;
4135
4136         key.objectid = subid;
4137         key.type = BTRFS_ROOT_ITEM_KEY;
4138         key.offset = (u64)-1;
4139         subvol_root = btrfs_read_fs_root_no_name(fs_info, &key);
4140         if (IS_ERR(subvol_root)) {
4141                 ret = PTR_ERR(subvol_root);
4142                 if (ret == -ENOENT)
4143                         ret = 1;
4144                 goto out;
4145         }
4146
4147         switch (type) {
4148         case BTRFS_UUID_KEY_SUBVOL:
4149                 if (memcmp(uuid, subvol_root->root_item.uuid, BTRFS_UUID_SIZE))
4150                         ret = 1;
4151                 break;
4152         case BTRFS_UUID_KEY_RECEIVED_SUBVOL:
4153                 if (memcmp(uuid, subvol_root->root_item.received_uuid,
4154                            BTRFS_UUID_SIZE))
4155                         ret = 1;
4156                 break;
4157         }
4158
4159 out:
4160         return ret;
4161 }
4162
4163 static int btrfs_uuid_rescan_kthread(void *data)
4164 {
4165         struct btrfs_fs_info *fs_info = (struct btrfs_fs_info *)data;
4166         int ret;
4167
4168         /*
4169          * 1st step is to iterate through the existing UUID tree and
4170          * to delete all entries that contain outdated data.
4171          * 2nd step is to add all missing entries to the UUID tree.
4172          */
4173         ret = btrfs_uuid_tree_iterate(fs_info, btrfs_check_uuid_tree_entry);
4174         if (ret < 0) {
4175                 btrfs_warn(fs_info, "iterating uuid_tree failed %d", ret);
4176                 up(&fs_info->uuid_tree_rescan_sem);
4177                 return ret;
4178         }
4179         return btrfs_uuid_scan_kthread(data);
4180 }
4181
4182 int btrfs_create_uuid_tree(struct btrfs_fs_info *fs_info)
4183 {
4184         struct btrfs_trans_handle *trans;
4185         struct btrfs_root *tree_root = fs_info->tree_root;
4186         struct btrfs_root *uuid_root;
4187         struct task_struct *task;
4188         int ret;
4189
4190         /*
4191          * 1 - root node
4192          * 1 - root item
4193          */
4194         trans = btrfs_start_transaction(tree_root, 2);
4195         if (IS_ERR(trans))
4196                 return PTR_ERR(trans);
4197
4198         uuid_root = btrfs_create_tree(trans, fs_info,
4199                                       BTRFS_UUID_TREE_OBJECTID);
4200         if (IS_ERR(uuid_root)) {
4201                 ret = PTR_ERR(uuid_root);
4202                 btrfs_abort_transaction(trans, tree_root, ret);
4203                 return ret;
4204         }
4205
4206         fs_info->uuid_root = uuid_root;
4207
4208         ret = btrfs_commit_transaction(trans, tree_root);
4209         if (ret)
4210                 return ret;
4211
4212         down(&fs_info->uuid_tree_rescan_sem);
4213         task = kthread_run(btrfs_uuid_scan_kthread, fs_info, "btrfs-uuid");
4214         if (IS_ERR(task)) {
4215                 /* fs_info->update_uuid_tree_gen remains 0 in all error case */
4216                 btrfs_warn(fs_info, "failed to start uuid_scan task");
4217                 up(&fs_info->uuid_tree_rescan_sem);
4218                 return PTR_ERR(task);
4219         }
4220
4221         return 0;
4222 }
4223
4224 int btrfs_check_uuid_tree(struct btrfs_fs_info *fs_info)
4225 {
4226         struct task_struct *task;
4227
4228         down(&fs_info->uuid_tree_rescan_sem);
4229         task = kthread_run(btrfs_uuid_rescan_kthread, fs_info, "btrfs-uuid");
4230         if (IS_ERR(task)) {
4231                 /* fs_info->update_uuid_tree_gen remains 0 in all error case */
4232                 btrfs_warn(fs_info, "failed to start uuid_rescan task");
4233                 up(&fs_info->uuid_tree_rescan_sem);
4234                 return PTR_ERR(task);
4235         }
4236
4237         return 0;
4238 }
4239
4240 /*
4241  * shrinking a device means finding all of the device extents past
4242  * the new size, and then following the back refs to the chunks.
4243  * The chunk relocation code actually frees the device extent
4244  */
4245 int btrfs_shrink_device(struct btrfs_device *device, u64 new_size)
4246 {
4247         struct btrfs_trans_handle *trans;
4248         struct btrfs_root *root = device->dev_root;
4249         struct btrfs_dev_extent *dev_extent = NULL;
4250         struct btrfs_path *path;
4251         u64 length;
4252         u64 chunk_offset;
4253         int ret;
4254         int slot;
4255         int failed = 0;
4256         bool retried = false;
4257         bool checked_pending_chunks = false;
4258         struct extent_buffer *l;
4259         struct btrfs_key key;
4260         struct btrfs_super_block *super_copy = root->fs_info->super_copy;
4261         u64 old_total = btrfs_super_total_bytes(super_copy);
4262         u64 old_size = btrfs_device_get_total_bytes(device);
4263         u64 diff = old_size - new_size;
4264
4265         if (device->is_tgtdev_for_dev_replace)
4266                 return -EINVAL;
4267
4268         path = btrfs_alloc_path();
4269         if (!path)
4270                 return -ENOMEM;
4271
4272         path->reada = 2;
4273
4274         lock_chunks(root);
4275
4276         btrfs_device_set_total_bytes(device, new_size);
4277         if (device->writeable) {
4278                 device->fs_devices->total_rw_bytes -= diff;
4279                 spin_lock(&root->fs_info->free_chunk_lock);
4280                 root->fs_info->free_chunk_space -= diff;
4281                 spin_unlock(&root->fs_info->free_chunk_lock);
4282         }
4283         unlock_chunks(root);
4284
4285 again:
4286         key.objectid = device->devid;
4287         key.offset = (u64)-1;
4288         key.type = BTRFS_DEV_EXTENT_KEY;
4289
4290         do {
4291                 mutex_lock(&root->fs_info->delete_unused_bgs_mutex);
4292                 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
4293                 if (ret < 0) {
4294                         mutex_unlock(&root->fs_info->delete_unused_bgs_mutex);
4295                         goto done;
4296                 }
4297
4298                 ret = btrfs_previous_item(root, path, 0, key.type);
4299                 if (ret)
4300                         mutex_unlock(&root->fs_info->delete_unused_bgs_mutex);
4301                 if (ret < 0)
4302                         goto done;
4303                 if (ret) {
4304                         ret = 0;
4305                         btrfs_release_path(path);
4306                         break;
4307                 }
4308
4309                 l = path->nodes[0];
4310                 slot = path->slots[0];
4311                 btrfs_item_key_to_cpu(l, &key, path->slots[0]);
4312
4313                 if (key.objectid != device->devid) {
4314                         mutex_unlock(&root->fs_info->delete_unused_bgs_mutex);
4315                         btrfs_release_path(path);
4316                         break;
4317                 }
4318
4319                 dev_extent = btrfs_item_ptr(l, slot, struct btrfs_dev_extent);
4320                 length = btrfs_dev_extent_length(l, dev_extent);
4321
4322                 if (key.offset + length <= new_size) {
4323                         mutex_unlock(&root->fs_info->delete_unused_bgs_mutex);
4324                         btrfs_release_path(path);
4325                         break;
4326                 }
4327
4328                 chunk_offset = btrfs_dev_extent_chunk_offset(l, dev_extent);
4329                 btrfs_release_path(path);
4330
4331                 ret = btrfs_relocate_chunk(root, chunk_offset);
4332                 mutex_unlock(&root->fs_info->delete_unused_bgs_mutex);
4333                 if (ret && ret != -ENOSPC)
4334                         goto done;
4335                 if (ret == -ENOSPC)
4336                         failed++;
4337         } while (key.offset-- > 0);
4338
4339         if (failed && !retried) {
4340                 failed = 0;
4341                 retried = true;
4342                 goto again;
4343         } else if (failed && retried) {
4344                 ret = -ENOSPC;
4345                 goto done;
4346         }
4347
4348         /* Shrinking succeeded, else we would be at "done". */
4349         trans = btrfs_start_transaction(root, 0);
4350         if (IS_ERR(trans)) {
4351                 ret = PTR_ERR(trans);
4352                 goto done;
4353         }
4354
4355         lock_chunks(root);
4356
4357         /*
4358          * We checked in the above loop all device extents that were already in
4359          * the device tree. However before we have updated the device's
4360          * total_bytes to the new size, we might have had chunk allocations that
4361          * have not complete yet (new block groups attached to transaction
4362          * handles), and therefore their device extents were not yet in the
4363          * device tree and we missed them in the loop above. So if we have any
4364          * pending chunk using a device extent that overlaps the device range
4365          * that we can not use anymore, commit the current transaction and
4366          * repeat the search on the device tree - this way we guarantee we will
4367          * not have chunks using device extents that end beyond 'new_size'.
4368          */
4369         if (!checked_pending_chunks) {
4370                 u64 start = new_size;
4371                 u64 len = old_size - new_size;
4372
4373                 if (contains_pending_extent(trans->transaction, device,
4374                                             &start, len)) {
4375                         unlock_chunks(root);
4376                         checked_pending_chunks = true;
4377                         failed = 0;
4378                         retried = false;
4379                         ret = btrfs_commit_transaction(trans, root);
4380                         if (ret)
4381                                 goto done;
4382                         goto again;
4383                 }
4384         }
4385
4386         btrfs_device_set_disk_total_bytes(device, new_size);
4387         if (list_empty(&device->resized_list))
4388                 list_add_tail(&device->resized_list,
4389                               &root->fs_info->fs_devices->resized_devices);
4390
4391         WARN_ON(diff > old_total);
4392         btrfs_set_super_total_bytes(super_copy, old_total - diff);
4393         unlock_chunks(root);
4394
4395         /* Now btrfs_update_device() will change the on-disk size. */
4396         ret = btrfs_update_device(trans, device);
4397         btrfs_end_transaction(trans, root);
4398 done:
4399         btrfs_free_path(path);
4400         if (ret) {
4401                 lock_chunks(root);
4402                 btrfs_device_set_total_bytes(device, old_size);
4403                 if (device->writeable)
4404                         device->fs_devices->total_rw_bytes += diff;
4405                 spin_lock(&root->fs_info->free_chunk_lock);
4406                 root->fs_info->free_chunk_space += diff;
4407                 spin_unlock(&root->fs_info->free_chunk_lock);
4408                 unlock_chunks(root);
4409         }
4410         return ret;
4411 }
4412
4413 static int btrfs_add_system_chunk(struct btrfs_root *root,
4414                            struct btrfs_key *key,
4415                            struct btrfs_chunk *chunk, int item_size)
4416 {
4417         struct btrfs_super_block *super_copy = root->fs_info->super_copy;
4418         struct btrfs_disk_key disk_key;
4419         u32 array_size;
4420         u8 *ptr;
4421
4422         lock_chunks(root);
4423         array_size = btrfs_super_sys_array_size(super_copy);
4424         if (array_size + item_size + sizeof(disk_key)
4425                         > BTRFS_SYSTEM_CHUNK_ARRAY_SIZE) {
4426                 unlock_chunks(root);
4427                 return -EFBIG;
4428         }
4429
4430         ptr = super_copy->sys_chunk_array + array_size;
4431         btrfs_cpu_key_to_disk(&disk_key, key);
4432         memcpy(ptr, &disk_key, sizeof(disk_key));
4433         ptr += sizeof(disk_key);
4434         memcpy(ptr, chunk, item_size);
4435         item_size += sizeof(disk_key);
4436         btrfs_set_super_sys_array_size(super_copy, array_size + item_size);
4437         unlock_chunks(root);
4438
4439         return 0;
4440 }
4441
4442 /*
4443  * sort the devices in descending order by max_avail, total_avail
4444  */
4445 static int btrfs_cmp_device_info(const void *a, const void *b)
4446 {
4447         const struct btrfs_device_info *di_a = a;
4448         const struct btrfs_device_info *di_b = b;
4449
4450         if (di_a->max_avail > di_b->max_avail)
4451                 return -1;
4452         if (di_a->max_avail < di_b->max_avail)
4453                 return 1;
4454         if (di_a->total_avail > di_b->total_avail)
4455                 return -1;
4456         if (di_a->total_avail < di_b->total_avail)
4457                 return 1;
4458         return 0;
4459 }
4460
4461 static u32 find_raid56_stripe_len(u32 data_devices, u32 dev_stripe_target)
4462 {
4463         /* TODO allow them to set a preferred stripe size */
4464         return 64 * 1024;
4465 }
4466
4467 static void check_raid56_incompat_flag(struct btrfs_fs_info *info, u64 type)
4468 {
4469         if (!(type & BTRFS_BLOCK_GROUP_RAID56_MASK))
4470                 return;
4471
4472         btrfs_set_fs_incompat(info, RAID56);
4473 }
4474
4475 #define BTRFS_MAX_DEVS(r) ((BTRFS_LEAF_DATA_SIZE(r)             \
4476                         - sizeof(struct btrfs_item)             \
4477                         - sizeof(struct btrfs_chunk))           \
4478                         / sizeof(struct btrfs_stripe) + 1)
4479
4480 #define BTRFS_MAX_DEVS_SYS_CHUNK ((BTRFS_SYSTEM_CHUNK_ARRAY_SIZE        \
4481                                 - 2 * sizeof(struct btrfs_disk_key)     \
4482                                 - 2 * sizeof(struct btrfs_chunk))       \
4483                                 / sizeof(struct btrfs_stripe) + 1)
4484
4485 static int __btrfs_alloc_chunk(struct btrfs_trans_handle *trans,
4486                                struct btrfs_root *extent_root, u64 start,
4487                                u64 type)
4488 {
4489         struct btrfs_fs_info *info = extent_root->fs_info;
4490         struct btrfs_fs_devices *fs_devices = info->fs_devices;
4491         struct list_head *cur;
4492         struct map_lookup *map = NULL;
4493         struct extent_map_tree *em_tree;
4494         struct extent_map *em;
4495         struct btrfs_device_info *devices_info = NULL;
4496         u64 total_avail;
4497         int num_stripes;        /* total number of stripes to allocate */
4498         int data_stripes;       /* number of stripes that count for
4499                                    block group size */
4500         int sub_stripes;        /* sub_stripes info for map */
4501         int dev_stripes;        /* stripes per dev */
4502         int devs_max;           /* max devs to use */
4503         int devs_min;           /* min devs needed */
4504         int devs_increment;     /* ndevs has to be a multiple of this */
4505         int ncopies;            /* how many copies to data has */
4506         int ret;
4507         u64 max_stripe_size;
4508         u64 max_chunk_size;
4509         u64 stripe_size;
4510         u64 num_bytes;
4511         u64 raid_stripe_len = BTRFS_STRIPE_LEN;
4512         int ndevs;
4513         int i;
4514         int j;
4515         int index;
4516
4517         BUG_ON(!alloc_profile_is_valid(type, 0));
4518
4519         if (list_empty(&fs_devices->alloc_list))
4520                 return -ENOSPC;
4521
4522         index = __get_raid_index(type);
4523
4524         sub_stripes = btrfs_raid_array[index].sub_stripes;
4525         dev_stripes = btrfs_raid_array[index].dev_stripes;
4526         devs_max = btrfs_raid_array[index].devs_max;
4527         devs_min = btrfs_raid_array[index].devs_min;
4528         devs_increment = btrfs_raid_array[index].devs_increment;
4529         ncopies = btrfs_raid_array[index].ncopies;
4530
4531         if (type & BTRFS_BLOCK_GROUP_DATA) {
4532                 max_stripe_size = 1024 * 1024 * 1024;
4533                 max_chunk_size = 10 * max_stripe_size;
4534                 if (!devs_max)
4535                         devs_max = BTRFS_MAX_DEVS(info->chunk_root);
4536         } else if (type & BTRFS_BLOCK_GROUP_METADATA) {
4537                 /* for larger filesystems, use larger metadata chunks */
4538                 if (fs_devices->total_rw_bytes > 50ULL * 1024 * 1024 * 1024)
4539                         max_stripe_size = 1024 * 1024 * 1024;
4540                 else
4541                         max_stripe_size = 256 * 1024 * 1024;
4542                 max_chunk_size = max_stripe_size;
4543                 if (!devs_max)
4544                         devs_max = BTRFS_MAX_DEVS(info->chunk_root);
4545         } else if (type & BTRFS_BLOCK_GROUP_SYSTEM) {
4546                 max_stripe_size = 32 * 1024 * 1024;
4547                 max_chunk_size = 2 * max_stripe_size;
4548                 if (!devs_max)
4549                         devs_max = BTRFS_MAX_DEVS_SYS_CHUNK;
4550         } else {
4551                 btrfs_err(info, "invalid chunk type 0x%llx requested",
4552                        type);
4553                 BUG_ON(1);
4554         }
4555
4556         /* we don't want a chunk larger than 10% of writeable space */
4557         max_chunk_size = min(div_factor(fs_devices->total_rw_bytes, 1),
4558                              max_chunk_size);
4559
4560         devices_info = kcalloc(fs_devices->rw_devices, sizeof(*devices_info),
4561                                GFP_NOFS);
4562         if (!devices_info)
4563                 return -ENOMEM;
4564
4565         cur = fs_devices->alloc_list.next;
4566
4567         /*
4568          * in the first pass through the devices list, we gather information
4569          * about the available holes on each device.
4570          */
4571         ndevs = 0;
4572         while (cur != &fs_devices->alloc_list) {
4573                 struct btrfs_device *device;
4574                 u64 max_avail;
4575                 u64 dev_offset;
4576
4577                 device = list_entry(cur, struct btrfs_device, dev_alloc_list);
4578
4579                 cur = cur->next;
4580
4581                 if (!device->writeable) {
4582                         WARN(1, KERN_ERR
4583                                "BTRFS: read-only device in alloc_list\n");
4584                         continue;
4585                 }
4586
4587                 if (!device->in_fs_metadata ||
4588                     device->is_tgtdev_for_dev_replace)
4589                         continue;
4590
4591                 if (device->total_bytes > device->bytes_used)
4592                         total_avail = device->total_bytes - device->bytes_used;
4593                 else
4594                         total_avail = 0;
4595
4596                 /* If there is no space on this device, skip it. */
4597                 if (total_avail == 0)
4598                         continue;
4599
4600                 ret = find_free_dev_extent(trans, device,
4601                                            max_stripe_size * dev_stripes,
4602                                            &dev_offset, &max_avail);
4603                 if (ret && ret != -ENOSPC)
4604                         goto error;
4605
4606                 if (ret == 0)
4607                         max_avail = max_stripe_size * dev_stripes;
4608
4609                 if (max_avail < BTRFS_STRIPE_LEN * dev_stripes)
4610                         continue;
4611
4612                 if (ndevs == fs_devices->rw_devices) {
4613                         WARN(1, "%s: found more than %llu devices\n",
4614                              __func__, fs_devices->rw_devices);
4615                         break;
4616                 }
4617                 devices_info[ndevs].dev_offset = dev_offset;
4618                 devices_info[ndevs].max_avail = max_avail;
4619                 devices_info[ndevs].total_avail = total_avail;
4620                 devices_info[ndevs].dev = device;
4621                 ++ndevs;
4622         }
4623
4624         /*
4625          * now sort the devices by hole size / available space
4626          */
4627         sort(devices_info, ndevs, sizeof(struct btrfs_device_info),
4628              btrfs_cmp_device_info, NULL);
4629
4630         /* round down to number of usable stripes */
4631         ndevs -= ndevs % devs_increment;
4632
4633         if (ndevs < devs_increment * sub_stripes || ndevs < devs_min) {
4634                 ret = -ENOSPC;
4635                 goto error;
4636         }
4637
4638         if (devs_max && ndevs > devs_max)
4639                 ndevs = devs_max;
4640         /*
4641          * the primary goal is to maximize the number of stripes, so use as many
4642          * devices as possible, even if the stripes are not maximum sized.
4643          */
4644         stripe_size = devices_info[ndevs-1].max_avail;
4645         num_stripes = ndevs * dev_stripes;
4646
4647         /*
4648          * this will have to be fixed for RAID1 and RAID10 over
4649          * more drives
4650          */
4651         data_stripes = num_stripes / ncopies;
4652
4653         if (type & BTRFS_BLOCK_GROUP_RAID5) {
4654                 raid_stripe_len = find_raid56_stripe_len(ndevs - 1,
4655                                  btrfs_super_stripesize(info->super_copy));
4656                 data_stripes = num_stripes - 1;
4657         }
4658         if (type & BTRFS_BLOCK_GROUP_RAID6) {
4659                 raid_stripe_len = find_raid56_stripe_len(ndevs - 2,
4660                                  btrfs_super_stripesize(info->super_copy));
4661                 data_stripes = num_stripes - 2;
4662         }
4663
4664         /*
4665          * Use the number of data stripes to figure out how big this chunk
4666          * is really going to be in terms of logical address space,
4667          * and compare that answer with the max chunk size
4668          */
4669         if (stripe_size * data_stripes > max_chunk_size) {
4670                 u64 mask = (1ULL << 24) - 1;
4671
4672                 stripe_size = div_u64(max_chunk_size, data_stripes);
4673
4674                 /* bump the answer up to a 16MB boundary */
4675                 stripe_size = (stripe_size + mask) & ~mask;
4676
4677                 /* but don't go higher than the limits we found
4678                  * while searching for free extents
4679                  */
4680                 if (stripe_size > devices_info[ndevs-1].max_avail)
4681                         stripe_size = devices_info[ndevs-1].max_avail;
4682         }
4683
4684         stripe_size = div_u64(stripe_size, dev_stripes);
4685
4686         /* align to BTRFS_STRIPE_LEN */
4687         stripe_size = div_u64(stripe_size, raid_stripe_len);
4688         stripe_size *= raid_stripe_len;
4689
4690         map = kmalloc(map_lookup_size(num_stripes), GFP_NOFS);
4691         if (!map) {
4692                 ret = -ENOMEM;
4693                 goto error;
4694         }
4695         map->num_stripes = num_stripes;
4696
4697         for (i = 0; i < ndevs; ++i) {
4698                 for (j = 0; j < dev_stripes; ++j) {
4699                         int s = i * dev_stripes + j;
4700                         map->stripes[s].dev = devices_info[i].dev;
4701                         map->stripes[s].physical = devices_info[i].dev_offset +
4702                                                    j * stripe_size;
4703                 }
4704         }
4705         map->sector_size = extent_root->sectorsize;
4706         map->stripe_len = raid_stripe_len;
4707         map->io_align = raid_stripe_len;
4708         map->io_width = raid_stripe_len;
4709         map->type = type;
4710         map->sub_stripes = sub_stripes;
4711
4712         num_bytes = stripe_size * data_stripes;
4713
4714         trace_btrfs_chunk_alloc(info->chunk_root, map, start, num_bytes);
4715
4716         em = alloc_extent_map();
4717         if (!em) {
4718                 kfree(map);
4719                 ret = -ENOMEM;
4720                 goto error;
4721         }
4722         set_bit(EXTENT_FLAG_FS_MAPPING, &em->flags);
4723         em->bdev = (struct block_device *)map;
4724         em->start = start;
4725         em->len = num_bytes;
4726         em->block_start = 0;
4727         em->block_len = em->len;
4728         em->orig_block_len = stripe_size;
4729
4730         em_tree = &extent_root->fs_info->mapping_tree.map_tree;
4731         write_lock(&em_tree->lock);
4732         ret = add_extent_mapping(em_tree, em, 0);
4733         if (!ret) {
4734                 list_add_tail(&em->list, &trans->transaction->pending_chunks);
4735                 atomic_inc(&em->refs);
4736         }
4737         write_unlock(&em_tree->lock);
4738         if (ret) {
4739                 free_extent_map(em);
4740                 goto error;
4741         }
4742
4743         ret = btrfs_make_block_group(trans, extent_root, 0, type,
4744                                      BTRFS_FIRST_CHUNK_TREE_OBJECTID,
4745                                      start, num_bytes);
4746         if (ret)
4747                 goto error_del_extent;
4748
4749         for (i = 0; i < map->num_stripes; i++) {
4750                 num_bytes = map->stripes[i].dev->bytes_used + stripe_size;
4751                 btrfs_device_set_bytes_used(map->stripes[i].dev, num_bytes);
4752         }
4753
4754         spin_lock(&extent_root->fs_info->free_chunk_lock);
4755         extent_root->fs_info->free_chunk_space -= (stripe_size *
4756                                                    map->num_stripes);
4757         spin_unlock(&extent_root->fs_info->free_chunk_lock);
4758
4759         free_extent_map(em);
4760         check_raid56_incompat_flag(extent_root->fs_info, type);
4761
4762         kfree(devices_info);
4763         return 0;
4764
4765 error_del_extent:
4766         write_lock(&em_tree->lock);
4767         remove_extent_mapping(em_tree, em);
4768         write_unlock(&em_tree->lock);
4769
4770         /* One for our allocation */
4771         free_extent_map(em);
4772         /* One for the tree reference */
4773         free_extent_map(em);
4774         /* One for the pending_chunks list reference */
4775         free_extent_map(em);
4776 error:
4777         kfree(devices_info);
4778         return ret;
4779 }
4780
4781 int btrfs_finish_chunk_alloc(struct btrfs_trans_handle *trans,
4782                                 struct btrfs_root *extent_root,
4783                                 u64 chunk_offset, u64 chunk_size)
4784 {
4785         struct btrfs_key key;
4786         struct btrfs_root *chunk_root = extent_root->fs_info->chunk_root;
4787         struct btrfs_device *device;
4788         struct btrfs_chunk *chunk;
4789         struct btrfs_stripe *stripe;
4790         struct extent_map_tree *em_tree;
4791         struct extent_map *em;
4792         struct map_lookup *map;
4793         size_t item_size;
4794         u64 dev_offset;
4795         u64 stripe_size;
4796         int i = 0;
4797         int ret;
4798
4799         em_tree = &extent_root->fs_info->mapping_tree.map_tree;
4800         read_lock(&em_tree->lock);
4801         em = lookup_extent_mapping(em_tree, chunk_offset, chunk_size);
4802         read_unlock(&em_tree->lock);
4803
4804         if (!em) {
4805                 btrfs_crit(extent_root->fs_info, "unable to find logical "
4806                            "%Lu len %Lu", chunk_offset, chunk_size);
4807                 return -EINVAL;
4808         }
4809
4810         if (em->start != chunk_offset || em->len != chunk_size) {
4811                 btrfs_crit(extent_root->fs_info, "found a bad mapping, wanted"
4812                           " %Lu-%Lu, found %Lu-%Lu", chunk_offset,
4813                           chunk_size, em->start, em->len);
4814                 free_extent_map(em);
4815                 return -EINVAL;
4816         }
4817
4818         map = (struct map_lookup *)em->bdev;
4819         item_size = btrfs_chunk_item_size(map->num_stripes);
4820         stripe_size = em->orig_block_len;
4821
4822         chunk = kzalloc(item_size, GFP_NOFS);
4823         if (!chunk) {
4824                 ret = -ENOMEM;
4825                 goto out;
4826         }
4827
4828         for (i = 0; i < map->num_stripes; i++) {
4829                 device = map->stripes[i].dev;
4830                 dev_offset = map->stripes[i].physical;
4831
4832                 ret = btrfs_update_device(trans, device);
4833                 if (ret)
4834                         goto out;
4835                 ret = btrfs_alloc_dev_extent(trans, device,
4836                                              chunk_root->root_key.objectid,
4837                                              BTRFS_FIRST_CHUNK_TREE_OBJECTID,
4838                                              chunk_offset, dev_offset,
4839                                              stripe_size);
4840                 if (ret)
4841                         goto out;
4842         }
4843
4844         stripe = &chunk->stripe;
4845         for (i = 0; i < map->num_stripes; i++) {
4846                 device = map->stripes[i].dev;
4847                 dev_offset = map->stripes[i].physical;
4848
4849                 btrfs_set_stack_stripe_devid(stripe, device->devid);
4850                 btrfs_set_stack_stripe_offset(stripe, dev_offset);
4851                 memcpy(stripe->dev_uuid, device->uuid, BTRFS_UUID_SIZE);
4852                 stripe++;
4853         }
4854
4855         btrfs_set_stack_chunk_length(chunk, chunk_size);
4856         btrfs_set_stack_chunk_owner(chunk, extent_root->root_key.objectid);
4857         btrfs_set_stack_chunk_stripe_len(chunk, map->stripe_len);
4858         btrfs_set_stack_chunk_type(chunk, map->type);
4859         btrfs_set_stack_chunk_num_stripes(chunk, map->num_stripes);
4860         btrfs_set_stack_chunk_io_align(chunk, map->stripe_len);
4861         btrfs_set_stack_chunk_io_width(chunk, map->stripe_len);
4862         btrfs_set_stack_chunk_sector_size(chunk, extent_root->sectorsize);
4863         btrfs_set_stack_chunk_sub_stripes(chunk, map->sub_stripes);
4864
4865         key.objectid = BTRFS_FIRST_CHUNK_TREE_OBJECTID;
4866         key.type = BTRFS_CHUNK_ITEM_KEY;
4867         key.offset = chunk_offset;
4868
4869         ret = btrfs_insert_item(trans, chunk_root, &key, chunk, item_size);
4870         if (ret == 0 && map->type & BTRFS_BLOCK_GROUP_SYSTEM) {
4871                 /*
4872                  * TODO: Cleanup of inserted chunk root in case of
4873                  * failure.
4874                  */
4875                 ret = btrfs_add_system_chunk(chunk_root, &key, chunk,
4876                                              item_size);
4877         }
4878
4879 out:
4880         kfree(chunk);
4881         free_extent_map(em);
4882         return ret;
4883 }
4884
4885 /*
4886  * Chunk allocation falls into two parts. The first part does works
4887  * that make the new allocated chunk useable, but not do any operation
4888  * that modifies the chunk tree. The second part does the works that
4889  * require modifying the chunk tree. This division is important for the
4890  * bootstrap process of adding storage to a seed btrfs.
4891  */
4892 int btrfs_alloc_chunk(struct btrfs_trans_handle *trans,
4893                       struct btrfs_root *extent_root, u64 type)
4894 {
4895         u64 chunk_offset;
4896
4897         ASSERT(mutex_is_locked(&extent_root->fs_info->chunk_mutex));
4898         chunk_offset = find_next_chunk(extent_root->fs_info);
4899         return __btrfs_alloc_chunk(trans, extent_root, chunk_offset, type);
4900 }
4901
4902 static noinline int init_first_rw_device(struct btrfs_trans_handle *trans,
4903                                          struct btrfs_root *root,
4904                                          struct btrfs_device *device)
4905 {
4906         u64 chunk_offset;
4907         u64 sys_chunk_offset;
4908         u64 alloc_profile;
4909         struct btrfs_fs_info *fs_info = root->fs_info;
4910         struct btrfs_root *extent_root = fs_info->extent_root;
4911         int ret;
4912
4913         chunk_offset = find_next_chunk(fs_info);
4914         alloc_profile = btrfs_get_alloc_profile(extent_root, 0);
4915         ret = __btrfs_alloc_chunk(trans, extent_root, chunk_offset,
4916                                   alloc_profile);
4917         if (ret)
4918                 return ret;
4919
4920         sys_chunk_offset = find_next_chunk(root->fs_info);
4921         alloc_profile = btrfs_get_alloc_profile(fs_info->chunk_root, 0);
4922         ret = __btrfs_alloc_chunk(trans, extent_root, sys_chunk_offset,
4923                                   alloc_profile);
4924         return ret;
4925 }
4926
4927 static inline int btrfs_chunk_max_errors(struct map_lookup *map)
4928 {
4929         int max_errors;
4930
4931         if (map->type & (BTRFS_BLOCK_GROUP_RAID1 |
4932                          BTRFS_BLOCK_GROUP_RAID10 |
4933                          BTRFS_BLOCK_GROUP_RAID5 |
4934                          BTRFS_BLOCK_GROUP_DUP)) {
4935                 max_errors = 1;
4936         } else if (map->type & BTRFS_BLOCK_GROUP_RAID6) {
4937                 max_errors = 2;
4938         } else {
4939                 max_errors = 0;
4940         }
4941
4942         return max_errors;
4943 }
4944
4945 int btrfs_chunk_readonly(struct btrfs_root *root, u64 chunk_offset)
4946 {
4947         struct extent_map *em;
4948         struct map_lookup *map;
4949         struct btrfs_mapping_tree *map_tree = &root->fs_info->mapping_tree;
4950         int readonly = 0;
4951         int miss_ndevs = 0;
4952         int i;
4953
4954         read_lock(&map_tree->map_tree.lock);
4955         em = lookup_extent_mapping(&map_tree->map_tree, chunk_offset, 1);
4956         read_unlock(&map_tree->map_tree.lock);
4957         if (!em)
4958                 return 1;
4959
4960         map = (struct map_lookup *)em->bdev;
4961         for (i = 0; i < map->num_stripes; i++) {
4962                 if (map->stripes[i].dev->missing) {
4963                         miss_ndevs++;
4964                         continue;
4965                 }
4966
4967                 if (!map->stripes[i].dev->writeable) {
4968                         readonly = 1;
4969                         goto end;
4970                 }
4971         }
4972
4973         /*
4974          * If the number of missing devices is larger than max errors,
4975          * we can not write the data into that chunk successfully, so
4976          * set it readonly.
4977          */
4978         if (miss_ndevs > btrfs_chunk_max_errors(map))
4979                 readonly = 1;
4980 end:
4981         free_extent_map(em);
4982         return readonly;
4983 }
4984
4985 void btrfs_mapping_init(struct btrfs_mapping_tree *tree)
4986 {
4987         extent_map_tree_init(&tree->map_tree);
4988 }
4989
4990 void btrfs_mapping_tree_free(struct btrfs_mapping_tree *tree)
4991 {
4992         struct extent_map *em;
4993
4994         while (1) {
4995                 write_lock(&tree->map_tree.lock);
4996                 em = lookup_extent_mapping(&tree->map_tree, 0, (u64)-1);
4997                 if (em)
4998                         remove_extent_mapping(&tree->map_tree, em);
4999                 write_unlock(&tree->map_tree.lock);
5000                 if (!em)
5001                         break;
5002                 /* once for us */
5003                 free_extent_map(em);
5004                 /* once for the tree */
5005                 free_extent_map(em);
5006         }
5007 }
5008
5009 int btrfs_num_copies(struct btrfs_fs_info *fs_info, u64 logical, u64 len)
5010 {
5011         struct btrfs_mapping_tree *map_tree = &fs_info->mapping_tree;
5012         struct extent_map *em;
5013         struct map_lookup *map;
5014         struct extent_map_tree *em_tree = &map_tree->map_tree;
5015         int ret;
5016
5017         read_lock(&em_tree->lock);
5018         em = lookup_extent_mapping(em_tree, logical, len);
5019         read_unlock(&em_tree->lock);
5020
5021         /*
5022          * We could return errors for these cases, but that could get ugly and
5023          * we'd probably do the same thing which is just not do anything else
5024          * and exit, so return 1 so the callers don't try to use other copies.
5025          */
5026         if (!em) {
5027                 btrfs_crit(fs_info, "No mapping for %Lu-%Lu", logical,
5028                             logical+len);
5029                 return 1;
5030         }
5031
5032         if (em->start > logical || em->start + em->len < logical) {
5033                 btrfs_crit(fs_info, "Invalid mapping for %Lu-%Lu, got "
5034                             "%Lu-%Lu", logical, logical+len, em->start,
5035                             em->start + em->len);
5036                 free_extent_map(em);
5037                 return 1;
5038         }
5039
5040         map = (struct map_lookup *)em->bdev;
5041         if (map->type & (BTRFS_BLOCK_GROUP_DUP | BTRFS_BLOCK_GROUP_RAID1))
5042                 ret = map->num_stripes;
5043         else if (map->type & BTRFS_BLOCK_GROUP_RAID10)
5044                 ret = map->sub_stripes;
5045         else if (map->type & BTRFS_BLOCK_GROUP_RAID5)
5046                 ret = 2;
5047         else if (map->type & BTRFS_BLOCK_GROUP_RAID6)
5048                 ret = 3;
5049         else
5050                 ret = 1;
5051         free_extent_map(em);
5052
5053         btrfs_dev_replace_lock(&fs_info->dev_replace);
5054         if (btrfs_dev_replace_is_ongoing(&fs_info->dev_replace))
5055                 ret++;
5056         btrfs_dev_replace_unlock(&fs_info->dev_replace);
5057
5058         return ret;
5059 }
5060
5061 unsigned long btrfs_full_stripe_len(struct btrfs_root *root,
5062                                     struct btrfs_mapping_tree *map_tree,
5063                                     u64 logical)
5064 {
5065         struct extent_map *em;
5066         struct map_lookup *map;
5067         struct extent_map_tree *em_tree = &map_tree->map_tree;
5068         unsigned long len = root->sectorsize;
5069
5070         read_lock(&em_tree->lock);
5071         em = lookup_extent_mapping(em_tree, logical, len);
5072         read_unlock(&em_tree->lock);
5073         BUG_ON(!em);
5074
5075         BUG_ON(em->start > logical || em->start + em->len < logical);
5076         map = (struct map_lookup *)em->bdev;
5077         if (map->type & BTRFS_BLOCK_GROUP_RAID56_MASK)
5078                 len = map->stripe_len * nr_data_stripes(map);
5079         free_extent_map(em);
5080         return len;
5081 }
5082
5083 int btrfs_is_parity_mirror(struct btrfs_mapping_tree *map_tree,
5084                            u64 logical, u64 len, int mirror_num)
5085 {
5086         struct extent_map *em;
5087         struct map_lookup *map;
5088         struct extent_map_tree *em_tree = &map_tree->map_tree;
5089         int ret = 0;
5090
5091         read_lock(&em_tree->lock);
5092         em = lookup_extent_mapping(em_tree, logical, len);
5093         read_unlock(&em_tree->lock);
5094         BUG_ON(!em);
5095
5096         BUG_ON(em->start > logical || em->start + em->len < logical);
5097         map = (struct map_lookup *)em->bdev;
5098         if (map->type & BTRFS_BLOCK_GROUP_RAID56_MASK)
5099                 ret = 1;
5100         free_extent_map(em);
5101         return ret;
5102 }
5103
5104 static int find_live_mirror(struct btrfs_fs_info *fs_info,
5105                             struct map_lookup *map, int first, int num,
5106                             int optimal, int dev_replace_is_ongoing)
5107 {
5108         int i;
5109         int tolerance;
5110         struct btrfs_device *srcdev;
5111
5112         if (dev_replace_is_ongoing &&
5113             fs_info->dev_replace.cont_reading_from_srcdev_mode ==
5114              BTRFS_DEV_REPLACE_ITEM_CONT_READING_FROM_SRCDEV_MODE_AVOID)
5115                 srcdev = fs_info->dev_replace.srcdev;
5116         else
5117                 srcdev = NULL;
5118
5119         /*
5120          * try to avoid the drive that is the source drive for a
5121          * dev-replace procedure, only choose it if no other non-missing
5122          * mirror is available
5123          */
5124         for (tolerance = 0; tolerance < 2; tolerance++) {
5125                 if (map->stripes[optimal].dev->bdev &&
5126                     (tolerance || map->stripes[optimal].dev != srcdev))
5127                         return optimal;
5128                 for (i = first; i < first + num; i++) {
5129                         if (map->stripes[i].dev->bdev &&
5130                             (tolerance || map->stripes[i].dev != srcdev))
5131                                 return i;
5132                 }
5133         }
5134
5135         /* we couldn't find one that doesn't fail.  Just return something
5136          * and the io error handling code will clean up eventually
5137          */
5138         return optimal;
5139 }
5140
5141 static inline int parity_smaller(u64 a, u64 b)
5142 {
5143         return a > b;
5144 }
5145
5146 /* Bubble-sort the stripe set to put the parity/syndrome stripes last */
5147 static void sort_parity_stripes(struct btrfs_bio *bbio, int num_stripes)
5148 {
5149         struct btrfs_bio_stripe s;
5150         int i;
5151         u64 l;
5152         int again = 1;
5153
5154         while (again) {
5155                 again = 0;
5156                 for (i = 0; i < num_stripes - 1; i++) {
5157                         if (parity_smaller(bbio->raid_map[i],
5158                                            bbio->raid_map[i+1])) {
5159                                 s = bbio->stripes[i];
5160                                 l = bbio->raid_map[i];
5161                                 bbio->stripes[i] = bbio->stripes[i+1];
5162                                 bbio->raid_map[i] = bbio->raid_map[i+1];
5163                                 bbio->stripes[i+1] = s;
5164                                 bbio->raid_map[i+1] = l;
5165
5166                                 again = 1;
5167                         }
5168                 }
5169         }
5170 }
5171
5172 static struct btrfs_bio *alloc_btrfs_bio(int total_stripes, int real_stripes)
5173 {
5174         struct btrfs_bio *bbio = kzalloc(
5175                  /* the size of the btrfs_bio */
5176                 sizeof(struct btrfs_bio) +
5177                 /* plus the variable array for the stripes */
5178                 sizeof(struct btrfs_bio_stripe) * (total_stripes) +
5179                 /* plus the variable array for the tgt dev */
5180                 sizeof(int) * (real_stripes) +
5181                 /*
5182                  * plus the raid_map, which includes both the tgt dev
5183                  * and the stripes
5184                  */
5185                 sizeof(u64) * (total_stripes),
5186                 GFP_NOFS|__GFP_NOFAIL);
5187
5188         atomic_set(&bbio->error, 0);
5189         atomic_set(&bbio->refs, 1);
5190
5191         return bbio;
5192 }
5193
5194 void btrfs_get_bbio(struct btrfs_bio *bbio)
5195 {
5196         WARN_ON(!atomic_read(&bbio->refs));
5197         atomic_inc(&bbio->refs);
5198 }
5199
5200 void btrfs_put_bbio(struct btrfs_bio *bbio)
5201 {
5202         if (!bbio)
5203                 return;
5204         if (atomic_dec_and_test(&bbio->refs))
5205                 kfree(bbio);
5206 }
5207
5208 static int __btrfs_map_block(struct btrfs_fs_info *fs_info, int rw,
5209                              u64 logical, u64 *length,
5210                              struct btrfs_bio **bbio_ret,
5211                              int mirror_num, int need_raid_map)
5212 {
5213         struct extent_map *em;
5214         struct map_lookup *map;
5215         struct btrfs_mapping_tree *map_tree = &fs_info->mapping_tree;
5216         struct extent_map_tree *em_tree = &map_tree->map_tree;
5217         u64 offset;
5218         u64 stripe_offset;
5219         u64 stripe_end_offset;
5220         u64 stripe_nr;
5221         u64 stripe_nr_orig;
5222         u64 stripe_nr_end;
5223         u64 stripe_len;
5224         u32 stripe_index;
5225         int i;
5226         int ret = 0;
5227         int num_stripes;
5228         int max_errors = 0;
5229         int tgtdev_indexes = 0;
5230         struct btrfs_bio *bbio = NULL;
5231         struct btrfs_dev_replace *dev_replace = &fs_info->dev_replace;
5232         int dev_replace_is_ongoing = 0;
5233         int num_alloc_stripes;
5234         int patch_the_first_stripe_for_dev_replace = 0;
5235         u64 physical_to_patch_in_first_stripe = 0;
5236         u64 raid56_full_stripe_start = (u64)-1;
5237
5238         read_lock(&em_tree->lock);
5239         em = lookup_extent_mapping(em_tree, logical, *length);
5240         read_unlock(&em_tree->lock);
5241
5242         if (!em) {
5243                 btrfs_crit(fs_info, "unable to find logical %llu len %llu",
5244                         logical, *length);
5245                 return -EINVAL;
5246         }
5247
5248         if (em->start > logical || em->start + em->len < logical) {
5249                 btrfs_crit(fs_info, "found a bad mapping, wanted %Lu, "
5250                            "found %Lu-%Lu", logical, em->start,
5251                            em->start + em->len);
5252                 free_extent_map(em);
5253                 return -EINVAL;
5254         }
5255
5256         map = (struct map_lookup *)em->bdev;
5257         offset = logical - em->start;
5258
5259         stripe_len = map->stripe_len;
5260         stripe_nr = offset;
5261         /*
5262          * stripe_nr counts the total number of stripes we have to stride
5263          * to get to this block
5264          */
5265         stripe_nr = div64_u64(stripe_nr, stripe_len);
5266
5267         stripe_offset = stripe_nr * stripe_len;
5268         BUG_ON(offset < stripe_offset);
5269
5270         /* stripe_offset is the offset of this block in its stripe*/
5271         stripe_offset = offset - stripe_offset;
5272
5273         /* if we're here for raid56, we need to know the stripe aligned start */
5274         if (map->type & BTRFS_BLOCK_GROUP_RAID56_MASK) {
5275                 unsigned long full_stripe_len = stripe_len * nr_data_stripes(map);
5276                 raid56_full_stripe_start = offset;
5277
5278                 /* allow a write of a full stripe, but make sure we don't
5279                  * allow straddling of stripes
5280                  */
5281                 raid56_full_stripe_start = div64_u64(raid56_full_stripe_start,
5282                                 full_stripe_len);
5283                 raid56_full_stripe_start *= full_stripe_len;
5284         }
5285
5286         if (rw & REQ_DISCARD) {
5287                 /* we don't discard raid56 yet */
5288                 if (map->type & BTRFS_BLOCK_GROUP_RAID56_MASK) {
5289                         ret = -EOPNOTSUPP;
5290                         goto out;
5291                 }
5292                 *length = min_t(u64, em->len - offset, *length);
5293         } else if (map->type & BTRFS_BLOCK_GROUP_PROFILE_MASK) {
5294                 u64 max_len;
5295                 /* For writes to RAID[56], allow a full stripeset across all disks.
5296                    For other RAID types and for RAID[56] reads, just allow a single
5297                    stripe (on a single disk). */
5298                 if ((map->type & BTRFS_BLOCK_GROUP_RAID56_MASK) &&
5299                     (rw & REQ_WRITE)) {
5300                         max_len = stripe_len * nr_data_stripes(map) -
5301                                 (offset - raid56_full_stripe_start);
5302                 } else {
5303                         /* we limit the length of each bio to what fits in a stripe */
5304                         max_len = stripe_len - stripe_offset;
5305                 }
5306                 *length = min_t(u64, em->len - offset, max_len);
5307         } else {
5308                 *length = em->len - offset;
5309         }
5310
5311         /* This is for when we're called from btrfs_merge_bio_hook() and all
5312            it cares about is the length */
5313         if (!bbio_ret)
5314                 goto out;
5315
5316         btrfs_dev_replace_lock(dev_replace);
5317         dev_replace_is_ongoing = btrfs_dev_replace_is_ongoing(dev_replace);
5318         if (!dev_replace_is_ongoing)
5319                 btrfs_dev_replace_unlock(dev_replace);
5320
5321         if (dev_replace_is_ongoing && mirror_num == map->num_stripes + 1 &&
5322             !(rw & (REQ_WRITE | REQ_DISCARD | REQ_GET_READ_MIRRORS)) &&
5323             dev_replace->tgtdev != NULL) {
5324                 /*
5325                  * in dev-replace case, for repair case (that's the only
5326                  * case where the mirror is selected explicitly when
5327                  * calling btrfs_map_block), blocks left of the left cursor
5328                  * can also be read from the target drive.
5329                  * For REQ_GET_READ_MIRRORS, the target drive is added as
5330                  * the last one to the array of stripes. For READ, it also
5331                  * needs to be supported using the same mirror number.
5332                  * If the requested block is not left of the left cursor,
5333                  * EIO is returned. This can happen because btrfs_num_copies()
5334                  * returns one more in the dev-replace case.
5335                  */
5336                 u64 tmp_length = *length;
5337                 struct btrfs_bio *tmp_bbio = NULL;
5338                 int tmp_num_stripes;
5339                 u64 srcdev_devid = dev_replace->srcdev->devid;
5340                 int index_srcdev = 0;
5341                 int found = 0;
5342                 u64 physical_of_found = 0;
5343
5344                 ret = __btrfs_map_block(fs_info, REQ_GET_READ_MIRRORS,
5345                              logical, &tmp_length, &tmp_bbio, 0, 0);
5346                 if (ret) {
5347                         WARN_ON(tmp_bbio != NULL);
5348                         goto out;
5349                 }
5350
5351                 tmp_num_stripes = tmp_bbio->num_stripes;
5352                 if (mirror_num > tmp_num_stripes) {
5353                         /*
5354                          * REQ_GET_READ_MIRRORS does not contain this
5355                          * mirror, that means that the requested area
5356                          * is not left of the left cursor
5357                          */
5358                         ret = -EIO;
5359                         btrfs_put_bbio(tmp_bbio);
5360                         goto out;
5361                 }
5362
5363                 /*
5364                  * process the rest of the function using the mirror_num
5365                  * of the source drive. Therefore look it up first.
5366                  * At the end, patch the device pointer to the one of the
5367                  * target drive.
5368                  */
5369                 for (i = 0; i < tmp_num_stripes; i++) {
5370                         if (tmp_bbio->stripes[i].dev->devid == srcdev_devid) {
5371                                 /*
5372                                  * In case of DUP, in order to keep it
5373                                  * simple, only add the mirror with the
5374                                  * lowest physical address
5375                                  */
5376                                 if (found &&
5377                                     physical_of_found <=
5378                                      tmp_bbio->stripes[i].physical)
5379                                         continue;
5380                                 index_srcdev = i;
5381                                 found = 1;
5382                                 physical_of_found =
5383                                         tmp_bbio->stripes[i].physical;
5384                         }
5385                 }
5386
5387                 if (found) {
5388                         mirror_num = index_srcdev + 1;
5389                         patch_the_first_stripe_for_dev_replace = 1;
5390                         physical_to_patch_in_first_stripe = physical_of_found;
5391                 } else {
5392                         WARN_ON(1);
5393                         ret = -EIO;
5394                         btrfs_put_bbio(tmp_bbio);
5395                         goto out;
5396                 }
5397
5398                 btrfs_put_bbio(tmp_bbio);
5399         } else if (mirror_num > map->num_stripes) {
5400                 mirror_num = 0;
5401         }
5402
5403         num_stripes = 1;
5404         stripe_index = 0;
5405         stripe_nr_orig = stripe_nr;
5406         stripe_nr_end = ALIGN(offset + *length, map->stripe_len);
5407         stripe_nr_end = div_u64(stripe_nr_end, map->stripe_len);
5408         stripe_end_offset = stripe_nr_end * map->stripe_len -
5409                             (offset + *length);
5410
5411         if (map->type & BTRFS_BLOCK_GROUP_RAID0) {
5412                 if (rw & REQ_DISCARD)
5413                         num_stripes = min_t(u64, map->num_stripes,
5414                                             stripe_nr_end - stripe_nr_orig);
5415                 stripe_nr = div_u64_rem(stripe_nr, map->num_stripes,
5416                                 &stripe_index);
5417                 if (!(rw & (REQ_WRITE | REQ_DISCARD | REQ_GET_READ_MIRRORS)))
5418                         mirror_num = 1;
5419         } else if (map->type & BTRFS_BLOCK_GROUP_RAID1) {
5420                 if (rw & (REQ_WRITE | REQ_DISCARD | REQ_GET_READ_MIRRORS))
5421                         num_stripes = map->num_stripes;
5422                 else if (mirror_num)
5423                         stripe_index = mirror_num - 1;
5424                 else {
5425                         stripe_index = find_live_mirror(fs_info, map, 0,
5426                                             map->num_stripes,
5427                                             current->pid % map->num_stripes,
5428                                             dev_replace_is_ongoing);
5429                         mirror_num = stripe_index + 1;
5430                 }
5431
5432         } else if (map->type & BTRFS_BLOCK_GROUP_DUP) {
5433                 if (rw & (REQ_WRITE | REQ_DISCARD | REQ_GET_READ_MIRRORS)) {
5434                         num_stripes = map->num_stripes;
5435                 } else if (mirror_num) {
5436                         stripe_index = mirror_num - 1;
5437                 } else {
5438                         mirror_num = 1;
5439                 }
5440
5441         } else if (map->type & BTRFS_BLOCK_GROUP_RAID10) {
5442                 u32 factor = map->num_stripes / map->sub_stripes;
5443
5444                 stripe_nr = div_u64_rem(stripe_nr, factor, &stripe_index);
5445                 stripe_index *= map->sub_stripes;
5446
5447                 if (rw & (REQ_WRITE | REQ_GET_READ_MIRRORS))
5448                         num_stripes = map->sub_stripes;
5449                 else if (rw & REQ_DISCARD)
5450                         num_stripes = min_t(u64, map->sub_stripes *
5451                                             (stripe_nr_end - stripe_nr_orig),
5452                                             map->num_stripes);
5453                 else if (mirror_num)
5454                         stripe_index += mirror_num - 1;
5455                 else {
5456                         int old_stripe_index = stripe_index;
5457                         stripe_index = find_live_mirror(fs_info, map,
5458                                               stripe_index,
5459                                               map->sub_stripes, stripe_index +
5460                                               current->pid % map->sub_stripes,
5461                                               dev_replace_is_ongoing);
5462                         mirror_num = stripe_index - old_stripe_index + 1;
5463                 }
5464
5465         } else if (map->type & BTRFS_BLOCK_GROUP_RAID56_MASK) {
5466                 if (need_raid_map &&
5467                     ((rw & (REQ_WRITE | REQ_GET_READ_MIRRORS)) ||
5468                      mirror_num > 1)) {
5469                         /* push stripe_nr back to the start of the full stripe */
5470                         stripe_nr = div_u64(raid56_full_stripe_start,
5471                                         stripe_len * nr_data_stripes(map));
5472
5473                         /* RAID[56] write or recovery. Return all stripes */
5474                         num_stripes = map->num_stripes;
5475                         max_errors = nr_parity_stripes(map);
5476
5477                         *length = map->stripe_len;
5478                         stripe_index = 0;
5479                         stripe_offset = 0;
5480                 } else {
5481                         /*
5482                          * Mirror #0 or #1 means the original data block.
5483                          * Mirror #2 is RAID5 parity block.
5484                          * Mirror #3 is RAID6 Q block.
5485                          */
5486                         stripe_nr = div_u64_rem(stripe_nr,
5487                                         nr_data_stripes(map), &stripe_index);
5488                         if (mirror_num > 1)
5489                                 stripe_index = nr_data_stripes(map) +
5490                                                 mirror_num - 2;
5491
5492                         /* We distribute the parity blocks across stripes */
5493                         div_u64_rem(stripe_nr + stripe_index, map->num_stripes,
5494                                         &stripe_index);
5495                         if (!(rw & (REQ_WRITE | REQ_DISCARD |
5496                                     REQ_GET_READ_MIRRORS)) && mirror_num <= 1)
5497                                 mirror_num = 1;
5498                 }
5499         } else {
5500                 /*
5501                  * after this, stripe_nr is the number of stripes on this
5502                  * device we have to walk to find the data, and stripe_index is
5503                  * the number of our device in the stripe array
5504                  */
5505                 stripe_nr = div_u64_rem(stripe_nr, map->num_stripes,
5506                                 &stripe_index);
5507                 mirror_num = stripe_index + 1;
5508         }
5509         BUG_ON(stripe_index >= map->num_stripes);
5510
5511         num_alloc_stripes = num_stripes;
5512         if (dev_replace_is_ongoing) {
5513                 if (rw & (REQ_WRITE | REQ_DISCARD))
5514                         num_alloc_stripes <<= 1;
5515                 if (rw & REQ_GET_READ_MIRRORS)
5516                         num_alloc_stripes++;
5517                 tgtdev_indexes = num_stripes;
5518         }
5519
5520         bbio = alloc_btrfs_bio(num_alloc_stripes, tgtdev_indexes);
5521         if (!bbio) {
5522                 ret = -ENOMEM;
5523                 goto out;
5524         }
5525         if (dev_replace_is_ongoing)
5526                 bbio->tgtdev_map = (int *)(bbio->stripes + num_alloc_stripes);
5527
5528         /* build raid_map */
5529         if (map->type & BTRFS_BLOCK_GROUP_RAID56_MASK &&
5530             need_raid_map && ((rw & (REQ_WRITE | REQ_GET_READ_MIRRORS)) ||
5531             mirror_num > 1)) {
5532                 u64 tmp;
5533                 unsigned rot;
5534
5535                 bbio->raid_map = (u64 *)((void *)bbio->stripes +
5536                                  sizeof(struct btrfs_bio_stripe) *
5537                                  num_alloc_stripes +
5538                                  sizeof(int) * tgtdev_indexes);
5539
5540                 /* Work out the disk rotation on this stripe-set */
5541                 div_u64_rem(stripe_nr, num_stripes, &rot);
5542
5543                 /* Fill in the logical address of each stripe */
5544                 tmp = stripe_nr * nr_data_stripes(map);
5545                 for (i = 0; i < nr_data_stripes(map); i++)
5546                         bbio->raid_map[(i+rot) % num_stripes] =
5547                                 em->start + (tmp + i) * map->stripe_len;
5548
5549                 bbio->raid_map[(i+rot) % map->num_stripes] = RAID5_P_STRIPE;
5550                 if (map->type & BTRFS_BLOCK_GROUP_RAID6)
5551                         bbio->raid_map[(i+rot+1) % num_stripes] =
5552                                 RAID6_Q_STRIPE;
5553         }
5554
5555         if (rw & REQ_DISCARD) {
5556                 u32 factor = 0;
5557                 u32 sub_stripes = 0;
5558                 u64 stripes_per_dev = 0;
5559                 u32 remaining_stripes = 0;
5560                 u32 last_stripe = 0;
5561
5562                 if (map->type &
5563                     (BTRFS_BLOCK_GROUP_RAID0 | BTRFS_BLOCK_GROUP_RAID10)) {
5564                         if (map->type & BTRFS_BLOCK_GROUP_RAID0)
5565                                 sub_stripes = 1;
5566                         else
5567                                 sub_stripes = map->sub_stripes;
5568
5569                         factor = map->num_stripes / sub_stripes;
5570                         stripes_per_dev = div_u64_rem(stripe_nr_end -
5571                                                       stripe_nr_orig,
5572                                                       factor,
5573                                                       &remaining_stripes);
5574                         div_u64_rem(stripe_nr_end - 1, factor, &last_stripe);
5575                         last_stripe *= sub_stripes;
5576                 }
5577
5578                 for (i = 0; i < num_stripes; i++) {
5579                         bbio->stripes[i].physical =
5580                                 map->stripes[stripe_index].physical +
5581                                 stripe_offset + stripe_nr * map->stripe_len;
5582                         bbio->stripes[i].dev = map->stripes[stripe_index].dev;
5583
5584                         if (map->type & (BTRFS_BLOCK_GROUP_RAID0 |
5585                                          BTRFS_BLOCK_GROUP_RAID10)) {
5586                                 bbio->stripes[i].length = stripes_per_dev *
5587                                                           map->stripe_len;
5588
5589                                 if (i / sub_stripes < remaining_stripes)
5590                                         bbio->stripes[i].length +=
5591                                                 map->stripe_len;
5592
5593                                 /*
5594                                  * Special for the first stripe and
5595                                  * the last stripe:
5596                                  *
5597                                  * |-------|...|-------|
5598                                  *     |----------|
5599                                  *    off     end_off
5600                                  */
5601                                 if (i < sub_stripes)
5602                                         bbio->stripes[i].length -=
5603                                                 stripe_offset;
5604
5605                                 if (stripe_index >= last_stripe &&
5606                                     stripe_index <= (last_stripe +
5607                                                      sub_stripes - 1))
5608                                         bbio->stripes[i].length -=
5609                                                 stripe_end_offset;
5610
5611                                 if (i == sub_stripes - 1)
5612                                         stripe_offset = 0;
5613                         } else
5614                                 bbio->stripes[i].length = *length;
5615
5616                         stripe_index++;
5617                         if (stripe_index == map->num_stripes) {
5618                                 /* This could only happen for RAID0/10 */
5619                                 stripe_index = 0;
5620                                 stripe_nr++;
5621                         }
5622                 }
5623         } else {
5624                 for (i = 0; i < num_stripes; i++) {
5625                         bbio->stripes[i].physical =
5626                                 map->stripes[stripe_index].physical +
5627                                 stripe_offset +
5628                                 stripe_nr * map->stripe_len;
5629                         bbio->stripes[i].dev =
5630                                 map->stripes[stripe_index].dev;
5631                         stripe_index++;
5632                 }
5633         }
5634
5635         if (rw & (REQ_WRITE | REQ_GET_READ_MIRRORS))
5636                 max_errors = btrfs_chunk_max_errors(map);
5637
5638         if (bbio->raid_map)
5639                 sort_parity_stripes(bbio, num_stripes);
5640
5641         tgtdev_indexes = 0;
5642         if (dev_replace_is_ongoing && (rw & (REQ_WRITE | REQ_DISCARD)) &&
5643             dev_replace->tgtdev != NULL) {
5644                 int index_where_to_add;
5645                 u64 srcdev_devid = dev_replace->srcdev->devid;
5646
5647                 /*
5648                  * duplicate the write operations while the dev replace
5649                  * procedure is running. Since the copying of the old disk
5650                  * to the new disk takes place at run time while the
5651                  * filesystem is mounted writable, the regular write
5652                  * operations to the old disk have to be duplicated to go
5653                  * to the new disk as well.
5654                  * Note that device->missing is handled by the caller, and
5655                  * that the write to the old disk is already set up in the
5656                  * stripes array.
5657                  */
5658                 index_where_to_add = num_stripes;
5659                 for (i = 0; i < num_stripes; i++) {
5660                         if (bbio->stripes[i].dev->devid == srcdev_devid) {
5661                                 /* write to new disk, too */
5662                                 struct btrfs_bio_stripe *new =
5663                                         bbio->stripes + index_where_to_add;
5664                                 struct btrfs_bio_stripe *old =
5665                                         bbio->stripes + i;
5666
5667                                 new->physical = old->physical;
5668                                 new->length = old->length;
5669                                 new->dev = dev_replace->tgtdev;
5670                                 bbio->tgtdev_map[i] = index_where_to_add;
5671                                 index_where_to_add++;
5672                                 max_errors++;
5673                                 tgtdev_indexes++;
5674                         }
5675                 }
5676                 num_stripes = index_where_to_add;
5677         } else if (dev_replace_is_ongoing && (rw & REQ_GET_READ_MIRRORS) &&
5678                    dev_replace->tgtdev != NULL) {
5679                 u64 srcdev_devid = dev_replace->srcdev->devid;
5680                 int index_srcdev = 0;
5681                 int found = 0;
5682                 u64 physical_of_found = 0;
5683
5684                 /*
5685                  * During the dev-replace procedure, the target drive can
5686                  * also be used to read data in case it is needed to repair
5687                  * a corrupt block elsewhere. This is possible if the
5688                  * requested area is left of the left cursor. In this area,
5689                  * the target drive is a full copy of the source drive.
5690                  */
5691                 for (i = 0; i < num_stripes; i++) {
5692                         if (bbio->stripes[i].dev->devid == srcdev_devid) {
5693                                 /*
5694                                  * In case of DUP, in order to keep it
5695                                  * simple, only add the mirror with the
5696                                  * lowest physical address
5697                                  */
5698                                 if (found &&
5699                                     physical_of_found <=
5700                                      bbio->stripes[i].physical)
5701                                         continue;
5702                                 index_srcdev = i;
5703                                 found = 1;
5704                                 physical_of_found = bbio->stripes[i].physical;
5705                         }
5706                 }
5707                 if (found) {
5708                         if (physical_of_found + map->stripe_len <=
5709                             dev_replace->cursor_left) {
5710                                 struct btrfs_bio_stripe *tgtdev_stripe =
5711                                         bbio->stripes + num_stripes;
5712
5713                                 tgtdev_stripe->physical = physical_of_found;
5714                                 tgtdev_stripe->length =
5715                                         bbio->stripes[index_srcdev].length;
5716                                 tgtdev_stripe->dev = dev_replace->tgtdev;
5717                                 bbio->tgtdev_map[index_srcdev] = num_stripes;
5718
5719                                 tgtdev_indexes++;
5720                                 num_stripes++;
5721                         }
5722                 }
5723         }
5724
5725         *bbio_ret = bbio;
5726         bbio->map_type = map->type;
5727         bbio->num_stripes = num_stripes;
5728         bbio->max_errors = max_errors;
5729         bbio->mirror_num = mirror_num;
5730         bbio->num_tgtdevs = tgtdev_indexes;
5731
5732         /*
5733          * this is the case that REQ_READ && dev_replace_is_ongoing &&
5734          * mirror_num == num_stripes + 1 && dev_replace target drive is
5735          * available as a mirror
5736          */
5737         if (patch_the_first_stripe_for_dev_replace && num_stripes > 0) {
5738                 WARN_ON(num_stripes > 1);
5739                 bbio->stripes[0].dev = dev_replace->tgtdev;
5740                 bbio->stripes[0].physical = physical_to_patch_in_first_stripe;
5741                 bbio->mirror_num = map->num_stripes + 1;
5742         }
5743 out:
5744         if (dev_replace_is_ongoing)
5745                 btrfs_dev_replace_unlock(dev_replace);
5746         free_extent_map(em);
5747         return ret;
5748 }
5749
5750 int btrfs_map_block(struct btrfs_fs_info *fs_info, int rw,
5751                       u64 logical, u64 *length,
5752                       struct btrfs_bio **bbio_ret, int mirror_num)
5753 {
5754         return __btrfs_map_block(fs_info, rw, logical, length, bbio_ret,
5755                                  mirror_num, 0);
5756 }
5757
5758 /* For Scrub/replace */
5759 int btrfs_map_sblock(struct btrfs_fs_info *fs_info, int rw,
5760                      u64 logical, u64 *length,
5761                      struct btrfs_bio **bbio_ret, int mirror_num,
5762                      int need_raid_map)
5763 {
5764         return __btrfs_map_block(fs_info, rw, logical, length, bbio_ret,
5765                                  mirror_num, need_raid_map);
5766 }
5767
5768 int btrfs_rmap_block(struct btrfs_mapping_tree *map_tree,
5769                      u64 chunk_start, u64 physical, u64 devid,
5770                      u64 **logical, int *naddrs, int *stripe_len)
5771 {
5772         struct extent_map_tree *em_tree = &map_tree->map_tree;
5773         struct extent_map *em;
5774         struct map_lookup *map;
5775         u64 *buf;
5776         u64 bytenr;
5777         u64 length;
5778         u64 stripe_nr;
5779         u64 rmap_len;
5780         int i, j, nr = 0;
5781
5782         read_lock(&em_tree->lock);
5783         em = lookup_extent_mapping(em_tree, chunk_start, 1);
5784         read_unlock(&em_tree->lock);
5785
5786         if (!em) {
5787                 printk(KERN_ERR "BTRFS: couldn't find em for chunk %Lu\n",
5788                        chunk_start);
5789                 return -EIO;
5790         }
5791
5792         if (em->start != chunk_start) {
5793                 printk(KERN_ERR "BTRFS: bad chunk start, em=%Lu, wanted=%Lu\n",
5794                        em->start, chunk_start);
5795                 free_extent_map(em);
5796                 return -EIO;
5797         }
5798         map = (struct map_lookup *)em->bdev;
5799
5800         length = em->len;
5801         rmap_len = map->stripe_len;
5802
5803         if (map->type & BTRFS_BLOCK_GROUP_RAID10)
5804                 length = div_u64(length, map->num_stripes / map->sub_stripes);
5805         else if (map->type & BTRFS_BLOCK_GROUP_RAID0)
5806                 length = div_u64(length, map->num_stripes);
5807         else if (map->type & BTRFS_BLOCK_GROUP_RAID56_MASK) {
5808                 length = div_u64(length, nr_data_stripes(map));
5809                 rmap_len = map->stripe_len * nr_data_stripes(map);
5810         }
5811
5812         buf = kcalloc(map->num_stripes, sizeof(u64), GFP_NOFS);
5813         BUG_ON(!buf); /* -ENOMEM */
5814
5815         for (i = 0; i < map->num_stripes; i++) {
5816                 if (devid && map->stripes[i].dev->devid != devid)
5817                         continue;
5818                 if (map->stripes[i].physical > physical ||
5819                     map->stripes[i].physical + length <= physical)
5820                         continue;
5821
5822                 stripe_nr = physical - map->stripes[i].physical;
5823                 stripe_nr = div_u64(stripe_nr, map->stripe_len);
5824
5825                 if (map->type & BTRFS_BLOCK_GROUP_RAID10) {
5826                         stripe_nr = stripe_nr * map->num_stripes + i;
5827                         stripe_nr = div_u64(stripe_nr, map->sub_stripes);
5828                 } else if (map->type & BTRFS_BLOCK_GROUP_RAID0) {
5829                         stripe_nr = stripe_nr * map->num_stripes + i;
5830                 } /* else if RAID[56], multiply by nr_data_stripes().
5831                    * Alternatively, just use rmap_len below instead of
5832                    * map->stripe_len */
5833
5834                 bytenr = chunk_start + stripe_nr * rmap_len;
5835                 WARN_ON(nr >= map->num_stripes);
5836                 for (j = 0; j < nr; j++) {
5837                         if (buf[j] == bytenr)
5838                                 break;
5839                 }
5840                 if (j == nr) {
5841                         WARN_ON(nr >= map->num_stripes);
5842                         buf[nr++] = bytenr;
5843                 }
5844         }
5845
5846         *logical = buf;
5847         *naddrs = nr;
5848         *stripe_len = rmap_len;
5849
5850         free_extent_map(em);
5851         return 0;
5852 }
5853
5854 static inline void btrfs_end_bbio(struct btrfs_bio *bbio, struct bio *bio)
5855 {
5856         bio->bi_private = bbio->private;
5857         bio->bi_end_io = bbio->end_io;
5858         bio_endio(bio);
5859
5860         btrfs_put_bbio(bbio);
5861 }
5862
5863 static void btrfs_end_bio(struct bio *bio)
5864 {
5865         struct btrfs_bio *bbio = bio->bi_private;
5866         int is_orig_bio = 0;
5867
5868         if (bio->bi_error) {
5869                 atomic_inc(&bbio->error);
5870                 if (bio->bi_error == -EIO || bio->bi_error == -EREMOTEIO) {
5871                         unsigned int stripe_index =
5872                                 btrfs_io_bio(bio)->stripe_index;
5873                         struct btrfs_device *dev;
5874
5875                         BUG_ON(stripe_index >= bbio->num_stripes);
5876                         dev = bbio->stripes[stripe_index].dev;
5877                         if (dev->bdev) {
5878                                 if (bio->bi_rw & WRITE)
5879                                         btrfs_dev_stat_inc(dev,
5880                                                 BTRFS_DEV_STAT_WRITE_ERRS);
5881                                 else
5882                                         btrfs_dev_stat_inc(dev,
5883                                                 BTRFS_DEV_STAT_READ_ERRS);
5884                                 if ((bio->bi_rw & WRITE_FLUSH) == WRITE_FLUSH)
5885                                         btrfs_dev_stat_inc(dev,
5886                                                 BTRFS_DEV_STAT_FLUSH_ERRS);
5887                                 btrfs_dev_stat_print_on_error(dev);
5888                         }
5889                 }
5890         }
5891
5892         if (bio == bbio->orig_bio)
5893                 is_orig_bio = 1;
5894
5895         btrfs_bio_counter_dec(bbio->fs_info);
5896
5897         if (atomic_dec_and_test(&bbio->stripes_pending)) {
5898                 if (!is_orig_bio) {
5899                         bio_put(bio);
5900                         bio = bbio->orig_bio;
5901                 }
5902
5903                 btrfs_io_bio(bio)->mirror_num = bbio->mirror_num;
5904                 /* only send an error to the higher layers if it is
5905                  * beyond the tolerance of the btrfs bio
5906                  */
5907                 if (atomic_read(&bbio->error) > bbio->max_errors) {
5908                         bio->bi_error = -EIO;
5909                 } else {
5910                         /*
5911                          * this bio is actually up to date, we didn't
5912                          * go over the max number of errors
5913                          */
5914                         bio->bi_error = 0;
5915                 }
5916
5917                 btrfs_end_bbio(bbio, bio);
5918         } else if (!is_orig_bio) {
5919                 bio_put(bio);
5920         }
5921 }
5922
5923 /*
5924  * see run_scheduled_bios for a description of why bios are collected for
5925  * async submit.
5926  *
5927  * This will add one bio to the pending list for a device and make sure
5928  * the work struct is scheduled.
5929  */
5930 static noinline void btrfs_schedule_bio(struct btrfs_root *root,
5931                                         struct btrfs_device *device,
5932                                         int rw, struct bio *bio)
5933 {
5934         int should_queue = 1;
5935         struct btrfs_pending_bios *pending_bios;
5936
5937         if (device->missing || !device->bdev) {
5938                 bio_io_error(bio);
5939                 return;
5940         }
5941
5942         /* don't bother with additional async steps for reads, right now */
5943         if (!(rw & REQ_WRITE)) {
5944                 bio_get(bio);
5945                 btrfsic_submit_bio(rw, bio);
5946                 bio_put(bio);
5947                 return;
5948         }
5949
5950         /*
5951          * nr_async_bios allows us to reliably return congestion to the
5952          * higher layers.  Otherwise, the async bio makes it appear we have
5953          * made progress against dirty pages when we've really just put it
5954          * on a queue for later
5955          */
5956         atomic_inc(&root->fs_info->nr_async_bios);
5957         WARN_ON(bio->bi_next);
5958         bio->bi_next = NULL;
5959         bio->bi_rw |= rw;
5960
5961         spin_lock(&device->io_lock);
5962         if (bio->bi_rw & REQ_SYNC)
5963                 pending_bios = &device->pending_sync_bios;
5964         else
5965                 pending_bios = &device->pending_bios;
5966
5967         if (pending_bios->tail)
5968                 pending_bios->tail->bi_next = bio;
5969
5970         pending_bios->tail = bio;
5971         if (!pending_bios->head)
5972                 pending_bios->head = bio;
5973         if (device->running_pending)
5974                 should_queue = 0;
5975
5976         spin_unlock(&device->io_lock);
5977
5978         if (should_queue)
5979                 btrfs_queue_work(root->fs_info->submit_workers,
5980                                  &device->work);
5981 }
5982
5983 static void submit_stripe_bio(struct btrfs_root *root, struct btrfs_bio *bbio,
5984                               struct bio *bio, u64 physical, int dev_nr,
5985                               int rw, int async)
5986 {
5987         struct btrfs_device *dev = bbio->stripes[dev_nr].dev;
5988
5989         bio->bi_private = bbio;
5990         btrfs_io_bio(bio)->stripe_index = dev_nr;
5991         bio->bi_end_io = btrfs_end_bio;
5992         bio->bi_iter.bi_sector = physical >> 9;
5993 #ifdef DEBUG
5994         {
5995                 struct rcu_string *name;
5996
5997                 rcu_read_lock();
5998                 name = rcu_dereference(dev->name);
5999                 pr_debug("btrfs_map_bio: rw %d, sector=%llu, dev=%lu "
6000                          "(%s id %llu), size=%u\n", rw,
6001                          (u64)bio->bi_iter.bi_sector, (u_long)dev->bdev->bd_dev,
6002                          name->str, dev->devid, bio->bi_iter.bi_size);
6003                 rcu_read_unlock();
6004         }
6005 #endif
6006         bio->bi_bdev = dev->bdev;
6007
6008         btrfs_bio_counter_inc_noblocked(root->fs_info);
6009
6010         if (async)
6011                 btrfs_schedule_bio(root, dev, rw, bio);
6012         else
6013                 btrfsic_submit_bio(rw, bio);
6014 }
6015
6016 static void bbio_error(struct btrfs_bio *bbio, struct bio *bio, u64 logical)
6017 {
6018         atomic_inc(&bbio->error);
6019         if (atomic_dec_and_test(&bbio->stripes_pending)) {
6020                 /* Shoud be the original bio. */
6021                 WARN_ON(bio != bbio->orig_bio);
6022
6023                 btrfs_io_bio(bio)->mirror_num = bbio->mirror_num;
6024                 bio->bi_iter.bi_sector = logical >> 9;
6025                 bio->bi_error = -EIO;
6026                 btrfs_end_bbio(bbio, bio);
6027         }
6028 }
6029
6030 int btrfs_map_bio(struct btrfs_root *root, int rw, struct bio *bio,
6031                   int mirror_num, int async_submit)
6032 {
6033         struct btrfs_device *dev;
6034         struct bio *first_bio = bio;
6035         u64 logical = (u64)bio->bi_iter.bi_sector << 9;
6036         u64 length = 0;
6037         u64 map_length;
6038         int ret;
6039         int dev_nr;
6040         int total_devs;
6041         struct btrfs_bio *bbio = NULL;
6042
6043         length = bio->bi_iter.bi_size;
6044         map_length = length;
6045
6046         btrfs_bio_counter_inc_blocked(root->fs_info);
6047         ret = __btrfs_map_block(root->fs_info, rw, logical, &map_length, &bbio,
6048                               mirror_num, 1);
6049         if (ret) {
6050                 btrfs_bio_counter_dec(root->fs_info);
6051                 return ret;
6052         }
6053
6054         total_devs = bbio->num_stripes;
6055         bbio->orig_bio = first_bio;
6056         bbio->private = first_bio->bi_private;
6057         bbio->end_io = first_bio->bi_end_io;
6058         bbio->fs_info = root->fs_info;
6059         atomic_set(&bbio->stripes_pending, bbio->num_stripes);
6060
6061         if (bbio->raid_map) {
6062                 /* In this case, map_length has been set to the length of
6063                    a single stripe; not the whole write */
6064                 if (rw & WRITE) {
6065                         ret = raid56_parity_write(root, bio, bbio, map_length);
6066                 } else {
6067                         ret = raid56_parity_recover(root, bio, bbio, map_length,
6068                                                     mirror_num, 1);
6069                 }
6070
6071                 btrfs_bio_counter_dec(root->fs_info);
6072                 return ret;
6073         }
6074
6075         if (map_length < length) {
6076                 btrfs_crit(root->fs_info, "mapping failed logical %llu bio len %llu len %llu",
6077                         logical, length, map_length);
6078                 BUG();
6079         }
6080
6081         for (dev_nr = 0; dev_nr < total_devs; dev_nr++) {
6082                 dev = bbio->stripes[dev_nr].dev;
6083                 if (!dev || !dev->bdev || (rw & WRITE && !dev->writeable)) {
6084                         bbio_error(bbio, first_bio, logical);
6085                         continue;
6086                 }
6087
6088                 if (dev_nr < total_devs - 1) {
6089                         bio = btrfs_bio_clone(first_bio, GFP_NOFS);
6090                         BUG_ON(!bio); /* -ENOMEM */
6091                 } else
6092                         bio = first_bio;
6093
6094                 submit_stripe_bio(root, bbio, bio,
6095                                   bbio->stripes[dev_nr].physical, dev_nr, rw,
6096                                   async_submit);
6097         }
6098         btrfs_bio_counter_dec(root->fs_info);
6099         return 0;
6100 }
6101
6102 struct btrfs_device *btrfs_find_device(struct btrfs_fs_info *fs_info, u64 devid,
6103                                        u8 *uuid, u8 *fsid)
6104 {
6105         struct btrfs_device *device;
6106         struct btrfs_fs_devices *cur_devices;
6107
6108         cur_devices = fs_info->fs_devices;
6109         while (cur_devices) {
6110                 if (!fsid ||
6111                     !memcmp(cur_devices->fsid, fsid, BTRFS_UUID_SIZE)) {
6112                         device = __find_device(&cur_devices->devices,
6113                                                devid, uuid);
6114                         if (device)
6115                                 return device;
6116                 }
6117                 cur_devices = cur_devices->seed;
6118         }
6119         return NULL;
6120 }
6121
6122 static struct btrfs_device *add_missing_dev(struct btrfs_root *root,
6123                                             struct btrfs_fs_devices *fs_devices,
6124                                             u64 devid, u8 *dev_uuid)
6125 {
6126         struct btrfs_device *device;
6127
6128         device = btrfs_alloc_device(NULL, &devid, dev_uuid);
6129         if (IS_ERR(device))
6130                 return NULL;
6131
6132         list_add(&device->dev_list, &fs_devices->devices);
6133         device->fs_devices = fs_devices;
6134         fs_devices->num_devices++;
6135
6136         device->missing = 1;
6137         fs_devices->missing_devices++;
6138
6139         return device;
6140 }
6141
6142 /**
6143  * btrfs_alloc_device - allocate struct btrfs_device
6144  * @fs_info:    used only for generating a new devid, can be NULL if
6145  *              devid is provided (i.e. @devid != NULL).
6146  * @devid:      a pointer to devid for this device.  If NULL a new devid
6147  *              is generated.
6148  * @uuid:       a pointer to UUID for this device.  If NULL a new UUID
6149  *              is generated.
6150  *
6151  * Return: a pointer to a new &struct btrfs_device on success; ERR_PTR()
6152  * on error.  Returned struct is not linked onto any lists and can be
6153  * destroyed with kfree() right away.
6154  */
6155 struct btrfs_device *btrfs_alloc_device(struct btrfs_fs_info *fs_info,
6156                                         const u64 *devid,
6157                                         const u8 *uuid)
6158 {
6159         struct btrfs_device *dev;
6160         u64 tmp;
6161
6162         if (WARN_ON(!devid && !fs_info))
6163                 return ERR_PTR(-EINVAL);
6164
6165         dev = __alloc_device();
6166         if (IS_ERR(dev))
6167                 return dev;
6168
6169         if (devid)
6170                 tmp = *devid;
6171         else {
6172                 int ret;
6173
6174                 ret = find_next_devid(fs_info, &tmp);
6175                 if (ret) {
6176                         kfree(dev);
6177                         return ERR_PTR(ret);
6178                 }
6179         }
6180         dev->devid = tmp;
6181
6182         if (uuid)
6183                 memcpy(dev->uuid, uuid, BTRFS_UUID_SIZE);
6184         else
6185                 generate_random_uuid(dev->uuid);
6186
6187         btrfs_init_work(&dev->work, btrfs_submit_helper,
6188                         pending_bios_fn, NULL, NULL);
6189
6190         return dev;
6191 }
6192
6193 static int read_one_chunk(struct btrfs_root *root, struct btrfs_key *key,
6194                           struct extent_buffer *leaf,
6195                           struct btrfs_chunk *chunk)
6196 {
6197         struct btrfs_mapping_tree *map_tree = &root->fs_info->mapping_tree;
6198         struct map_lookup *map;
6199         struct extent_map *em;
6200         u64 logical;
6201         u64 length;
6202         u64 devid;
6203         u8 uuid[BTRFS_UUID_SIZE];
6204         int num_stripes;
6205         int ret;
6206         int i;
6207
6208         logical = key->offset;
6209         length = btrfs_chunk_length(leaf, chunk);
6210
6211         read_lock(&map_tree->map_tree.lock);
6212         em = lookup_extent_mapping(&map_tree->map_tree, logical, 1);
6213         read_unlock(&map_tree->map_tree.lock);
6214
6215         /* already mapped? */
6216         if (em && em->start <= logical && em->start + em->len > logical) {
6217                 free_extent_map(em);
6218                 return 0;
6219         } else if (em) {
6220                 free_extent_map(em);
6221         }
6222
6223         em = alloc_extent_map();
6224         if (!em)
6225                 return -ENOMEM;
6226         num_stripes = btrfs_chunk_num_stripes(leaf, chunk);
6227         map = kmalloc(map_lookup_size(num_stripes), GFP_NOFS);
6228         if (!map) {
6229                 free_extent_map(em);
6230                 return -ENOMEM;
6231         }
6232
6233         set_bit(EXTENT_FLAG_FS_MAPPING, &em->flags);
6234         em->bdev = (struct block_device *)map;
6235         em->start = logical;
6236         em->len = length;
6237         em->orig_start = 0;
6238         em->block_start = 0;
6239         em->block_len = em->len;
6240
6241         map->num_stripes = num_stripes;
6242         map->io_width = btrfs_chunk_io_width(leaf, chunk);
6243         map->io_align = btrfs_chunk_io_align(leaf, chunk);
6244         map->sector_size = btrfs_chunk_sector_size(leaf, chunk);
6245         map->stripe_len = btrfs_chunk_stripe_len(leaf, chunk);
6246         map->type = btrfs_chunk_type(leaf, chunk);
6247         map->sub_stripes = btrfs_chunk_sub_stripes(leaf, chunk);
6248         for (i = 0; i < num_stripes; i++) {
6249                 map->stripes[i].physical =
6250                         btrfs_stripe_offset_nr(leaf, chunk, i);
6251                 devid = btrfs_stripe_devid_nr(leaf, chunk, i);
6252                 read_extent_buffer(leaf, uuid, (unsigned long)
6253                                    btrfs_stripe_dev_uuid_nr(chunk, i),
6254                                    BTRFS_UUID_SIZE);
6255                 map->stripes[i].dev = btrfs_find_device(root->fs_info, devid,
6256                                                         uuid, NULL);
6257                 if (!map->stripes[i].dev && !btrfs_test_opt(root, DEGRADED)) {
6258                         free_extent_map(em);
6259                         return -EIO;
6260                 }
6261                 if (!map->stripes[i].dev) {
6262                         map->stripes[i].dev =
6263                                 add_missing_dev(root, root->fs_info->fs_devices,
6264                                                 devid, uuid);
6265                         if (!map->stripes[i].dev) {
6266                                 free_extent_map(em);
6267                                 return -EIO;
6268                         }
6269                         btrfs_warn(root->fs_info, "devid %llu uuid %pU is missing",
6270                                                 devid, uuid);
6271                 }
6272                 map->stripes[i].dev->in_fs_metadata = 1;
6273         }
6274
6275         write_lock(&map_tree->map_tree.lock);
6276         ret = add_extent_mapping(&map_tree->map_tree, em, 0);
6277         write_unlock(&map_tree->map_tree.lock);
6278         BUG_ON(ret); /* Tree corruption */
6279         free_extent_map(em);
6280
6281         return 0;
6282 }
6283
6284 static void fill_device_from_item(struct extent_buffer *leaf,
6285                                  struct btrfs_dev_item *dev_item,
6286                                  struct btrfs_device *device)
6287 {
6288         unsigned long ptr;
6289
6290         device->devid = btrfs_device_id(leaf, dev_item);
6291         device->disk_total_bytes = btrfs_device_total_bytes(leaf, dev_item);
6292         device->total_bytes = device->disk_total_bytes;
6293         device->commit_total_bytes = device->disk_total_bytes;
6294         device->bytes_used = btrfs_device_bytes_used(leaf, dev_item);
6295         device->commit_bytes_used = device->bytes_used;
6296         device->type = btrfs_device_type(leaf, dev_item);
6297         device->io_align = btrfs_device_io_align(leaf, dev_item);
6298         device->io_width = btrfs_device_io_width(leaf, dev_item);
6299         device->sector_size = btrfs_device_sector_size(leaf, dev_item);
6300         WARN_ON(device->devid == BTRFS_DEV_REPLACE_DEVID);
6301         device->is_tgtdev_for_dev_replace = 0;
6302
6303         ptr = btrfs_device_uuid(dev_item);
6304         read_extent_buffer(leaf, device->uuid, ptr, BTRFS_UUID_SIZE);
6305 }
6306
6307 static struct btrfs_fs_devices *open_seed_devices(struct btrfs_root *root,
6308                                                   u8 *fsid)
6309 {
6310         struct btrfs_fs_devices *fs_devices;
6311         int ret;
6312
6313         BUG_ON(!mutex_is_locked(&uuid_mutex));
6314
6315         fs_devices = root->fs_info->fs_devices->seed;
6316         while (fs_devices) {
6317                 if (!memcmp(fs_devices->fsid, fsid, BTRFS_UUID_SIZE))
6318                         return fs_devices;
6319
6320                 fs_devices = fs_devices->seed;
6321         }
6322
6323         fs_devices = find_fsid(fsid);
6324         if (!fs_devices) {
6325                 if (!btrfs_test_opt(root, DEGRADED))
6326                         return ERR_PTR(-ENOENT);
6327
6328                 fs_devices = alloc_fs_devices(fsid);
6329                 if (IS_ERR(fs_devices))
6330                         return fs_devices;
6331
6332                 fs_devices->seeding = 1;
6333                 fs_devices->opened = 1;
6334                 return fs_devices;
6335         }
6336
6337         fs_devices = clone_fs_devices(fs_devices);
6338         if (IS_ERR(fs_devices))
6339                 return fs_devices;
6340
6341         ret = __btrfs_open_devices(fs_devices, FMODE_READ,
6342                                    root->fs_info->bdev_holder);
6343         if (ret) {
6344                 free_fs_devices(fs_devices);
6345                 fs_devices = ERR_PTR(ret);
6346                 goto out;
6347         }
6348
6349         if (!fs_devices->seeding) {
6350                 __btrfs_close_devices(fs_devices);
6351                 free_fs_devices(fs_devices);
6352                 fs_devices = ERR_PTR(-EINVAL);
6353                 goto out;
6354         }
6355
6356         fs_devices->seed = root->fs_info->fs_devices->seed;
6357         root->fs_info->fs_devices->seed = fs_devices;
6358 out:
6359         return fs_devices;
6360 }
6361
6362 static int read_one_dev(struct btrfs_root *root,
6363                         struct extent_buffer *leaf,
6364                         struct btrfs_dev_item *dev_item)
6365 {
6366         struct btrfs_fs_devices *fs_devices = root->fs_info->fs_devices;
6367         struct btrfs_device *device;
6368         u64 devid;
6369         int ret;
6370         u8 fs_uuid[BTRFS_UUID_SIZE];
6371         u8 dev_uuid[BTRFS_UUID_SIZE];
6372
6373         devid = btrfs_device_id(leaf, dev_item);
6374         read_extent_buffer(leaf, dev_uuid, btrfs_device_uuid(dev_item),
6375                            BTRFS_UUID_SIZE);
6376         read_extent_buffer(leaf, fs_uuid, btrfs_device_fsid(dev_item),
6377                            BTRFS_UUID_SIZE);
6378
6379         if (memcmp(fs_uuid, root->fs_info->fsid, BTRFS_UUID_SIZE)) {
6380                 fs_devices = open_seed_devices(root, fs_uuid);
6381                 if (IS_ERR(fs_devices))
6382                         return PTR_ERR(fs_devices);
6383         }
6384
6385         device = btrfs_find_device(root->fs_info, devid, dev_uuid, fs_uuid);
6386         if (!device) {
6387                 if (!btrfs_test_opt(root, DEGRADED))
6388                         return -EIO;
6389
6390                 device = add_missing_dev(root, fs_devices, devid, dev_uuid);
6391                 if (!device)
6392                         return -ENOMEM;
6393                 btrfs_warn(root->fs_info, "devid %llu uuid %pU missing",
6394                                 devid, dev_uuid);
6395         } else {
6396                 if (!device->bdev && !btrfs_test_opt(root, DEGRADED))
6397                         return -EIO;
6398
6399                 if(!device->bdev && !device->missing) {
6400                         /*
6401                          * this happens when a device that was properly setup
6402                          * in the device info lists suddenly goes bad.
6403                          * device->bdev is NULL, and so we have to set
6404                          * device->missing to one here
6405                          */
6406                         device->fs_devices->missing_devices++;
6407                         device->missing = 1;
6408                 }
6409
6410                 /* Move the device to its own fs_devices */
6411                 if (device->fs_devices != fs_devices) {
6412                         ASSERT(device->missing);
6413
6414                         list_move(&device->dev_list, &fs_devices->devices);
6415                         device->fs_devices->num_devices--;
6416                         fs_devices->num_devices++;
6417
6418                         device->fs_devices->missing_devices--;
6419                         fs_devices->missing_devices++;
6420
6421                         device->fs_devices = fs_devices;
6422                 }
6423         }
6424
6425         if (device->fs_devices != root->fs_info->fs_devices) {
6426                 BUG_ON(device->writeable);
6427                 if (device->generation !=
6428                     btrfs_device_generation(leaf, dev_item))
6429                         return -EINVAL;
6430         }
6431
6432         fill_device_from_item(leaf, dev_item, device);
6433         device->in_fs_metadata = 1;
6434         if (device->writeable && !device->is_tgtdev_for_dev_replace) {
6435                 device->fs_devices->total_rw_bytes += device->total_bytes;
6436                 spin_lock(&root->fs_info->free_chunk_lock);
6437                 root->fs_info->free_chunk_space += device->total_bytes -
6438                         device->bytes_used;
6439                 spin_unlock(&root->fs_info->free_chunk_lock);
6440         }
6441         ret = 0;
6442         return ret;
6443 }
6444
6445 int btrfs_read_sys_array(struct btrfs_root *root)
6446 {
6447         struct btrfs_super_block *super_copy = root->fs_info->super_copy;
6448         struct extent_buffer *sb;
6449         struct btrfs_disk_key *disk_key;
6450         struct btrfs_chunk *chunk;
6451         u8 *array_ptr;
6452         unsigned long sb_array_offset;
6453         int ret = 0;
6454         u32 num_stripes;
6455         u32 array_size;
6456         u32 len = 0;
6457         u32 cur_offset;
6458         struct btrfs_key key;
6459
6460         ASSERT(BTRFS_SUPER_INFO_SIZE <= root->nodesize);
6461         /*
6462          * This will create extent buffer of nodesize, superblock size is
6463          * fixed to BTRFS_SUPER_INFO_SIZE. If nodesize > sb size, this will
6464          * overallocate but we can keep it as-is, only the first page is used.
6465          */
6466         sb = btrfs_find_create_tree_block(root, BTRFS_SUPER_INFO_OFFSET);
6467         if (!sb)
6468                 return -ENOMEM;
6469         btrfs_set_buffer_uptodate(sb);
6470         btrfs_set_buffer_lockdep_class(root->root_key.objectid, sb, 0);
6471         /*
6472          * The sb extent buffer is artifical and just used to read the system array.
6473          * btrfs_set_buffer_uptodate() call does not properly mark all it's
6474          * pages up-to-date when the page is larger: extent does not cover the
6475          * whole page and consequently check_page_uptodate does not find all
6476          * the page's extents up-to-date (the hole beyond sb),
6477          * write_extent_buffer then triggers a WARN_ON.
6478          *
6479          * Regular short extents go through mark_extent_buffer_dirty/writeback cycle,
6480          * but sb spans only this function. Add an explicit SetPageUptodate call
6481          * to silence the warning eg. on PowerPC 64.
6482          */
6483         if (PAGE_CACHE_SIZE > BTRFS_SUPER_INFO_SIZE)
6484                 SetPageUptodate(sb->pages[0]);
6485
6486         write_extent_buffer(sb, super_copy, 0, BTRFS_SUPER_INFO_SIZE);
6487         array_size = btrfs_super_sys_array_size(super_copy);
6488
6489         array_ptr = super_copy->sys_chunk_array;
6490         sb_array_offset = offsetof(struct btrfs_super_block, sys_chunk_array);
6491         cur_offset = 0;
6492
6493         while (cur_offset < array_size) {
6494                 disk_key = (struct btrfs_disk_key *)array_ptr;
6495                 len = sizeof(*disk_key);
6496                 if (cur_offset + len > array_size)
6497                         goto out_short_read;
6498
6499                 btrfs_disk_key_to_cpu(&key, disk_key);
6500
6501                 array_ptr += len;
6502                 sb_array_offset += len;
6503                 cur_offset += len;
6504
6505                 if (key.type == BTRFS_CHUNK_ITEM_KEY) {
6506                         chunk = (struct btrfs_chunk *)sb_array_offset;
6507                         /*
6508                          * At least one btrfs_chunk with one stripe must be
6509                          * present, exact stripe count check comes afterwards
6510                          */
6511                         len = btrfs_chunk_item_size(1);
6512                         if (cur_offset + len > array_size)
6513                                 goto out_short_read;
6514
6515                         num_stripes = btrfs_chunk_num_stripes(sb, chunk);
6516                         len = btrfs_chunk_item_size(num_stripes);
6517                         if (cur_offset + len > array_size)
6518                                 goto out_short_read;
6519
6520                         ret = read_one_chunk(root, &key, sb, chunk);
6521                         if (ret)
6522                                 break;
6523                 } else {
6524                         ret = -EIO;
6525                         break;
6526                 }
6527                 array_ptr += len;
6528                 sb_array_offset += len;
6529                 cur_offset += len;
6530         }
6531         free_extent_buffer(sb);
6532         return ret;
6533
6534 out_short_read:
6535         printk(KERN_ERR "BTRFS: sys_array too short to read %u bytes at offset %u\n",
6536                         len, cur_offset);
6537         free_extent_buffer(sb);
6538         return -EIO;
6539 }
6540
6541 int btrfs_read_chunk_tree(struct btrfs_root *root)
6542 {
6543         struct btrfs_path *path;
6544         struct extent_buffer *leaf;
6545         struct btrfs_key key;
6546         struct btrfs_key found_key;
6547         int ret;
6548         int slot;
6549
6550         root = root->fs_info->chunk_root;
6551
6552         path = btrfs_alloc_path();
6553         if (!path)
6554                 return -ENOMEM;
6555
6556         mutex_lock(&uuid_mutex);
6557         lock_chunks(root);
6558
6559         /*
6560          * Read all device items, and then all the chunk items. All
6561          * device items are found before any chunk item (their object id
6562          * is smaller than the lowest possible object id for a chunk
6563          * item - BTRFS_FIRST_CHUNK_TREE_OBJECTID).
6564          */
6565         key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
6566         key.offset = 0;
6567         key.type = 0;
6568         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
6569         if (ret < 0)
6570                 goto error;
6571         while (1) {
6572                 leaf = path->nodes[0];
6573                 slot = path->slots[0];
6574                 if (slot >= btrfs_header_nritems(leaf)) {
6575                         ret = btrfs_next_leaf(root, path);
6576                         if (ret == 0)
6577                                 continue;
6578                         if (ret < 0)
6579                                 goto error;
6580                         break;
6581                 }
6582                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
6583                 if (found_key.type == BTRFS_DEV_ITEM_KEY) {
6584                         struct btrfs_dev_item *dev_item;
6585                         dev_item = btrfs_item_ptr(leaf, slot,
6586                                                   struct btrfs_dev_item);
6587                         ret = read_one_dev(root, leaf, dev_item);
6588                         if (ret)
6589                                 goto error;
6590                 } else if (found_key.type == BTRFS_CHUNK_ITEM_KEY) {
6591                         struct btrfs_chunk *chunk;
6592                         chunk = btrfs_item_ptr(leaf, slot, struct btrfs_chunk);
6593                         ret = read_one_chunk(root, &found_key, leaf, chunk);
6594                         if (ret)
6595                                 goto error;
6596                 }
6597                 path->slots[0]++;
6598         }
6599         ret = 0;
6600 error:
6601         unlock_chunks(root);
6602         mutex_unlock(&uuid_mutex);
6603
6604         btrfs_free_path(path);
6605         return ret;
6606 }
6607
6608 void btrfs_init_devices_late(struct btrfs_fs_info *fs_info)
6609 {
6610         struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
6611         struct btrfs_device *device;
6612
6613         while (fs_devices) {
6614                 mutex_lock(&fs_devices->device_list_mutex);
6615                 list_for_each_entry(device, &fs_devices->devices, dev_list)
6616                         device->dev_root = fs_info->dev_root;
6617                 mutex_unlock(&fs_devices->device_list_mutex);
6618
6619                 fs_devices = fs_devices->seed;
6620         }
6621 }
6622
6623 static void __btrfs_reset_dev_stats(struct btrfs_device *dev)
6624 {
6625         int i;
6626
6627         for (i = 0; i < BTRFS_DEV_STAT_VALUES_MAX; i++)
6628                 btrfs_dev_stat_reset(dev, i);
6629 }
6630
6631 int btrfs_init_dev_stats(struct btrfs_fs_info *fs_info)
6632 {
6633         struct btrfs_key key;
6634         struct btrfs_key found_key;
6635         struct btrfs_root *dev_root = fs_info->dev_root;
6636         struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
6637         struct extent_buffer *eb;
6638         int slot;
6639         int ret = 0;
6640         struct btrfs_device *device;
6641         struct btrfs_path *path = NULL;
6642         int i;
6643
6644         path = btrfs_alloc_path();
6645         if (!path) {
6646                 ret = -ENOMEM;
6647                 goto out;
6648         }
6649
6650         mutex_lock(&fs_devices->device_list_mutex);
6651         list_for_each_entry(device, &fs_devices->devices, dev_list) {
6652                 int item_size;
6653                 struct btrfs_dev_stats_item *ptr;
6654
6655                 key.objectid = 0;
6656                 key.type = BTRFS_DEV_STATS_KEY;
6657                 key.offset = device->devid;
6658                 ret = btrfs_search_slot(NULL, dev_root, &key, path, 0, 0);
6659                 if (ret) {
6660                         __btrfs_reset_dev_stats(device);
6661                         device->dev_stats_valid = 1;
6662                         btrfs_release_path(path);
6663                         continue;
6664                 }
6665                 slot = path->slots[0];
6666                 eb = path->nodes[0];
6667                 btrfs_item_key_to_cpu(eb, &found_key, slot);
6668                 item_size = btrfs_item_size_nr(eb, slot);
6669
6670                 ptr = btrfs_item_ptr(eb, slot,
6671                                      struct btrfs_dev_stats_item);
6672
6673                 for (i = 0; i < BTRFS_DEV_STAT_VALUES_MAX; i++) {
6674                         if (item_size >= (1 + i) * sizeof(__le64))
6675                                 btrfs_dev_stat_set(device, i,
6676                                         btrfs_dev_stats_value(eb, ptr, i));
6677                         else
6678                                 btrfs_dev_stat_reset(device, i);
6679                 }
6680
6681                 device->dev_stats_valid = 1;
6682                 btrfs_dev_stat_print_on_load(device);
6683                 btrfs_release_path(path);
6684         }
6685         mutex_unlock(&fs_devices->device_list_mutex);
6686
6687 out:
6688         btrfs_free_path(path);
6689         return ret < 0 ? ret : 0;
6690 }
6691
6692 static int update_dev_stat_item(struct btrfs_trans_handle *trans,
6693                                 struct btrfs_root *dev_root,
6694                                 struct btrfs_device *device)
6695 {
6696         struct btrfs_path *path;
6697         struct btrfs_key key;
6698         struct extent_buffer *eb;
6699         struct btrfs_dev_stats_item *ptr;
6700         int ret;
6701         int i;
6702
6703         key.objectid = 0;
6704         key.type = BTRFS_DEV_STATS_KEY;
6705         key.offset = device->devid;
6706
6707         path = btrfs_alloc_path();
6708         BUG_ON(!path);
6709         ret = btrfs_search_slot(trans, dev_root, &key, path, -1, 1);
6710         if (ret < 0) {
6711                 btrfs_warn_in_rcu(dev_root->fs_info,
6712                         "error %d while searching for dev_stats item for device %s",
6713                               ret, rcu_str_deref(device->name));
6714                 goto out;
6715         }
6716
6717         if (ret == 0 &&
6718             btrfs_item_size_nr(path->nodes[0], path->slots[0]) < sizeof(*ptr)) {
6719                 /* need to delete old one and insert a new one */
6720                 ret = btrfs_del_item(trans, dev_root, path);
6721                 if (ret != 0) {
6722                         btrfs_warn_in_rcu(dev_root->fs_info,
6723                                 "delete too small dev_stats item for device %s failed %d",
6724                                       rcu_str_deref(device->name), ret);
6725                         goto out;
6726                 }
6727                 ret = 1;
6728         }
6729
6730         if (ret == 1) {
6731                 /* need to insert a new item */
6732                 btrfs_release_path(path);
6733                 ret = btrfs_insert_empty_item(trans, dev_root, path,
6734                                               &key, sizeof(*ptr));
6735                 if (ret < 0) {
6736                         btrfs_warn_in_rcu(dev_root->fs_info,
6737                                 "insert dev_stats item for device %s failed %d",
6738                                 rcu_str_deref(device->name), ret);
6739                         goto out;
6740                 }
6741         }
6742
6743         eb = path->nodes[0];
6744         ptr = btrfs_item_ptr(eb, path->slots[0], struct btrfs_dev_stats_item);
6745         for (i = 0; i < BTRFS_DEV_STAT_VALUES_MAX; i++)
6746                 btrfs_set_dev_stats_value(eb, ptr, i,
6747                                           btrfs_dev_stat_read(device, i));
6748         btrfs_mark_buffer_dirty(eb);
6749
6750 out:
6751         btrfs_free_path(path);
6752         return ret;
6753 }
6754
6755 /*
6756  * called from commit_transaction. Writes all changed device stats to disk.
6757  */
6758 int btrfs_run_dev_stats(struct btrfs_trans_handle *trans,
6759                         struct btrfs_fs_info *fs_info)
6760 {
6761         struct btrfs_root *dev_root = fs_info->dev_root;
6762         struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
6763         struct btrfs_device *device;
6764         int stats_cnt;
6765         int ret = 0;
6766
6767         mutex_lock(&fs_devices->device_list_mutex);
6768         list_for_each_entry(device, &fs_devices->devices, dev_list) {
6769                 if (!device->dev_stats_valid || !btrfs_dev_stats_dirty(device))
6770                         continue;
6771
6772                 stats_cnt = atomic_read(&device->dev_stats_ccnt);
6773                 ret = update_dev_stat_item(trans, dev_root, device);
6774                 if (!ret)
6775                         atomic_sub(stats_cnt, &device->dev_stats_ccnt);
6776         }
6777         mutex_unlock(&fs_devices->device_list_mutex);
6778
6779         return ret;
6780 }
6781
6782 void btrfs_dev_stat_inc_and_print(struct btrfs_device *dev, int index)
6783 {
6784         btrfs_dev_stat_inc(dev, index);
6785         btrfs_dev_stat_print_on_error(dev);
6786 }
6787
6788 static void btrfs_dev_stat_print_on_error(struct btrfs_device *dev)
6789 {
6790         if (!dev->dev_stats_valid)
6791                 return;
6792         btrfs_err_rl_in_rcu(dev->dev_root->fs_info,
6793                 "bdev %s errs: wr %u, rd %u, flush %u, corrupt %u, gen %u",
6794                            rcu_str_deref(dev->name),
6795                            btrfs_dev_stat_read(dev, BTRFS_DEV_STAT_WRITE_ERRS),
6796                            btrfs_dev_stat_read(dev, BTRFS_DEV_STAT_READ_ERRS),
6797                            btrfs_dev_stat_read(dev, BTRFS_DEV_STAT_FLUSH_ERRS),
6798                            btrfs_dev_stat_read(dev, BTRFS_DEV_STAT_CORRUPTION_ERRS),
6799                            btrfs_dev_stat_read(dev, BTRFS_DEV_STAT_GENERATION_ERRS));
6800 }
6801
6802 static void btrfs_dev_stat_print_on_load(struct btrfs_device *dev)
6803 {
6804         int i;
6805
6806         for (i = 0; i < BTRFS_DEV_STAT_VALUES_MAX; i++)
6807                 if (btrfs_dev_stat_read(dev, i) != 0)
6808                         break;
6809         if (i == BTRFS_DEV_STAT_VALUES_MAX)
6810                 return; /* all values == 0, suppress message */
6811
6812         btrfs_info_in_rcu(dev->dev_root->fs_info,
6813                 "bdev %s errs: wr %u, rd %u, flush %u, corrupt %u, gen %u",
6814                rcu_str_deref(dev->name),
6815                btrfs_dev_stat_read(dev, BTRFS_DEV_STAT_WRITE_ERRS),
6816                btrfs_dev_stat_read(dev, BTRFS_DEV_STAT_READ_ERRS),
6817                btrfs_dev_stat_read(dev, BTRFS_DEV_STAT_FLUSH_ERRS),
6818                btrfs_dev_stat_read(dev, BTRFS_DEV_STAT_CORRUPTION_ERRS),
6819                btrfs_dev_stat_read(dev, BTRFS_DEV_STAT_GENERATION_ERRS));
6820 }
6821
6822 int btrfs_get_dev_stats(struct btrfs_root *root,
6823                         struct btrfs_ioctl_get_dev_stats *stats)
6824 {
6825         struct btrfs_device *dev;
6826         struct btrfs_fs_devices *fs_devices = root->fs_info->fs_devices;
6827         int i;
6828
6829         mutex_lock(&fs_devices->device_list_mutex);
6830         dev = btrfs_find_device(root->fs_info, stats->devid, NULL, NULL);
6831         mutex_unlock(&fs_devices->device_list_mutex);
6832
6833         if (!dev) {
6834                 btrfs_warn(root->fs_info, "get dev_stats failed, device not found");
6835                 return -ENODEV;
6836         } else if (!dev->dev_stats_valid) {
6837                 btrfs_warn(root->fs_info, "get dev_stats failed, not yet valid");
6838                 return -ENODEV;
6839         } else if (stats->flags & BTRFS_DEV_STATS_RESET) {
6840                 for (i = 0; i < BTRFS_DEV_STAT_VALUES_MAX; i++) {
6841                         if (stats->nr_items > i)
6842                                 stats->values[i] =
6843                                         btrfs_dev_stat_read_and_reset(dev, i);
6844                         else
6845                                 btrfs_dev_stat_reset(dev, i);
6846                 }
6847         } else {
6848                 for (i = 0; i < BTRFS_DEV_STAT_VALUES_MAX; i++)
6849                         if (stats->nr_items > i)
6850                                 stats->values[i] = btrfs_dev_stat_read(dev, i);
6851         }
6852         if (stats->nr_items > BTRFS_DEV_STAT_VALUES_MAX)
6853                 stats->nr_items = BTRFS_DEV_STAT_VALUES_MAX;
6854         return 0;
6855 }
6856
6857 void btrfs_scratch_superblocks(struct block_device *bdev, char *device_path)
6858 {
6859         struct buffer_head *bh;
6860         struct btrfs_super_block *disk_super;
6861         int copy_num;
6862
6863         if (!bdev)
6864                 return;
6865
6866         for (copy_num = 0; copy_num < BTRFS_SUPER_MIRROR_MAX;
6867                 copy_num++) {
6868
6869                 if (btrfs_read_dev_one_super(bdev, copy_num, &bh))
6870                         continue;
6871
6872                 disk_super = (struct btrfs_super_block *)bh->b_data;
6873
6874                 memset(&disk_super->magic, 0, sizeof(disk_super->magic));
6875                 set_buffer_dirty(bh);
6876                 sync_dirty_buffer(bh);
6877                 brelse(bh);
6878         }
6879
6880         /* Notify udev that device has changed */
6881         btrfs_kobject_uevent(bdev, KOBJ_CHANGE);
6882
6883         /* Update ctime/mtime for device path for libblkid */
6884         update_dev_time(device_path);
6885 }
6886
6887 /*
6888  * Update the size of all devices, which is used for writing out the
6889  * super blocks.
6890  */
6891 void btrfs_update_commit_device_size(struct btrfs_fs_info *fs_info)
6892 {
6893         struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
6894         struct btrfs_device *curr, *next;
6895
6896         if (list_empty(&fs_devices->resized_devices))
6897                 return;
6898
6899         mutex_lock(&fs_devices->device_list_mutex);
6900         lock_chunks(fs_info->dev_root);
6901         list_for_each_entry_safe(curr, next, &fs_devices->resized_devices,
6902                                  resized_list) {
6903                 list_del_init(&curr->resized_list);
6904                 curr->commit_total_bytes = curr->disk_total_bytes;
6905         }
6906         unlock_chunks(fs_info->dev_root);
6907         mutex_unlock(&fs_devices->device_list_mutex);
6908 }
6909
6910 /* Must be invoked during the transaction commit */
6911 void btrfs_update_commit_device_bytes_used(struct btrfs_root *root,
6912                                         struct btrfs_transaction *transaction)
6913 {
6914         struct extent_map *em;
6915         struct map_lookup *map;
6916         struct btrfs_device *dev;
6917         int i;
6918
6919         if (list_empty(&transaction->pending_chunks))
6920                 return;
6921
6922         /* In order to kick the device replace finish process */
6923         lock_chunks(root);
6924         list_for_each_entry(em, &transaction->pending_chunks, list) {
6925                 map = (struct map_lookup *)em->bdev;
6926
6927                 for (i = 0; i < map->num_stripes; i++) {
6928                         dev = map->stripes[i].dev;
6929                         dev->commit_bytes_used = dev->bytes_used;
6930                 }
6931         }
6932         unlock_chunks(root);
6933 }
6934
6935 void btrfs_set_fs_info_ptr(struct btrfs_fs_info *fs_info)
6936 {
6937         struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
6938         while (fs_devices) {
6939                 fs_devices->fs_info = fs_info;
6940                 fs_devices = fs_devices->seed;
6941         }
6942 }
6943
6944 void btrfs_reset_fs_info_ptr(struct btrfs_fs_info *fs_info)
6945 {
6946         struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
6947         while (fs_devices) {
6948                 fs_devices->fs_info = NULL;
6949                 fs_devices = fs_devices->seed;
6950         }
6951 }
6952
6953 void btrfs_close_one_device(struct btrfs_device *device)
6954 {
6955         struct btrfs_fs_devices *fs_devices = device->fs_devices;
6956         struct btrfs_device *new_device;
6957         struct rcu_string *name;
6958
6959         if (device->bdev)
6960                 fs_devices->open_devices--;
6961
6962         if (device->writeable &&
6963             device->devid != BTRFS_DEV_REPLACE_DEVID) {
6964                 list_del_init(&device->dev_alloc_list);
6965                 fs_devices->rw_devices--;
6966         }
6967
6968         if (device->missing)
6969                 fs_devices->missing_devices--;
6970
6971         new_device = btrfs_alloc_device(NULL, &device->devid,
6972                                         device->uuid);
6973         BUG_ON(IS_ERR(new_device)); /* -ENOMEM */
6974
6975         /* Safe because we are under uuid_mutex */
6976         if (device->name) {
6977                 name = rcu_string_strdup(device->name->str, GFP_NOFS);
6978                 BUG_ON(!name); /* -ENOMEM */
6979                 rcu_assign_pointer(new_device->name, name);
6980         }
6981
6982         list_replace_rcu(&device->dev_list, &new_device->dev_list);
6983         new_device->fs_devices = device->fs_devices;
6984
6985         call_rcu(&device->rcu, free_device);
6986 }