fs/nilfs2/super.c

   1 /*
   2  * super.c - NILFS module and super block management.
   3  *
   4  * Copyright (C) 2005-2008 Nippon Telegraph and Telephone Corporation.
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation; either version 2 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program; if not, write to the Free Software
  18  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  19  *
  20  * Written by Ryusuke Konishi <ryusuke@osrg.net>
  21  */
  22 /*
  23  *  linux/fs/ext2/super.c
  24  *
  25  * Copyright (C) 1992, 1993, 1994, 1995
  26  * Remy Card (card@masi.ibp.fr)
  27  * Laboratoire MASI - Institut Blaise Pascal
  28  * Universite Pierre et Marie Curie (Paris VI)
  29  *
  30  *  from
  31  *
  32  *  linux/fs/minix/inode.c
  33  *
  34  *  Copyright (C) 1991, 1992  Linus Torvalds
  35  *
  36  *  Big-endian to little-endian byte-swapping/bitmaps by
  37  *        David S. Miller (davem@caip.rutgers.edu), 1995
  38  */
  39
  40 #include <linux/module.h>
  41 #include <linux/string.h>
  42 #include <linux/slab.h>
  43 #include <linux/init.h>
  44 #include <linux/blkdev.h>
  45 #include <linux/parser.h>
  46 #include <linux/crc32.h>
  47 #include <linux/vfs.h>
  48 #include <linux/writeback.h>
  49 #include <linux/seq_file.h>
  50 #include <linux/mount.h>
  51 #include "nilfs.h"
  52 #include "export.h"
  53 #include "mdt.h"
  54 #include "alloc.h"
  55 #include "btree.h"
  56 #include "btnode.h"
  57 #include "page.h"
  58 #include "cpfile.h"
  59 #include "ifile.h"
  60 #include "dat.h"
  61 #include "segment.h"
  62 #include "segbuf.h"
  63
  64 MODULE_AUTHOR("NTT Corp.");
  65 MODULE_DESCRIPTION("A New Implementation of the Log-structured Filesystem "
  66                    "(NILFS)");
  67 MODULE_LICENSE("GPL");
  68
  69 static struct kmem_cache *nilfs_inode_cachep;
  70 struct kmem_cache *nilfs_transaction_cachep;
  71 struct kmem_cache *nilfs_segbuf_cachep;
  72 struct kmem_cache *nilfs_btree_path_cache;
  73
  74 static int nilfs_setup_super(struct nilfs_sb_info *sbi, int is_mount);
  75 static int nilfs_remount(struct super_block *sb, int *flags, char *data);
  76
  77 static void nilfs_set_error(struct nilfs_sb_info *sbi)
  78 {
  79         struct the_nilfs *nilfs = sbi->s_nilfs;
  80         struct nilfs_super_block **sbp;
  81
  82         down_write(&nilfs->ns_sem);
  83         if (!(nilfs->ns_mount_state & NILFS_ERROR_FS)) {
  84                 nilfs->ns_mount_state |= NILFS_ERROR_FS;
  85                 sbp = nilfs_prepare_super(sbi, 0);
  86                 if (likely(sbp)) {
  87                         sbp[0]->s_state |= cpu_to_le16(NILFS_ERROR_FS);
  88                         if (sbp[1])
  89                                 sbp[1]->s_state |= cpu_to_le16(NILFS_ERROR_FS);
  90                         nilfs_commit_super(sbi, NILFS_SB_COMMIT_ALL);
  91                 }
  92         }
  93         up_write(&nilfs->ns_sem);
  94 }
  95
  96 /**
  97  * nilfs_error() - report failure condition on a filesystem
  98  *
  99  * nilfs_error() sets an ERROR_FS flag on the superblock as well as
 100  * reporting an error message.  It should be called when NILFS detects
 101  * incoherences or defects of meta data on disk.  As for sustainable
 102  * errors such as a single-shot I/O error, nilfs_warning() or the printk()
 103  * function should be used instead.
 104  *
 105  * The segment constructor must not call this function because it can
 106  * kill itself.
 107  */
 108 void nilfs_error(struct super_block *sb, const char *function,
 109                  const char *fmt, ...)
 110 {
 111         struct the_nilfs *nilfs = sbi->s_nilfs;
 112         struct va_format vaf;
 113         va_list args;
 114
 115         va_start(args, fmt);
 116
 117         vaf.fmt = fmt;
 118         vaf.va = &args;
 119
 120         printk(KERN_CRIT "NILFS error (device %s): %s: %pV\n",
 121                sb->s_id, function, &vaf);
 122
 123         va_end(args);
 124
 125         if (!(sb->s_flags & MS_RDONLY)) {
 126                 nilfs_set_error(sbi);
 127
 128                 if (nilfs_test_opt(nilfs, ERRORS_RO)) {
 129                         printk(KERN_CRIT "Remounting filesystem read-only\n");
 130                         sb->s_flags |= MS_RDONLY;
 131                 }
 132         }
 133
 134         if (nilfs_test_opt(nilfs, ERRORS_PANIC))
 135                 panic("NILFS (device %s): panic forced after error\n",
 136                       sb->s_id);
 137 }
 138
 139 void nilfs_warning(struct super_block *sb, const char *function,
 140                    const char *fmt, ...)
 141 {
 142         struct va_format vaf;
 143         va_list args;
 144
 145         va_start(args, fmt);
 146
 147         vaf.fmt = fmt;
 148         vaf.va = &args;
 149
 150         printk(KERN_WARNING "NILFS warning (device %s): %s: %pV\n",
 151                sb->s_id, function, &vaf);
 152
 153         va_end(args);
 154 }
 155
 156
 157 struct inode *nilfs_alloc_inode(struct super_block *sb)
 158 {
 159         struct nilfs_inode_info *ii;
 160
 161         ii = kmem_cache_alloc(nilfs_inode_cachep, GFP_NOFS);
 162         if (!ii)
 163                 return NULL;
 164         ii->i_bh = NULL;
 165         ii->i_state = 0;
 166         ii->i_cno = 0;
 167         ii->vfs_inode.i_version = 1;
 168         nilfs_btnode_cache_init(&ii->i_btnode_cache, sb->s_bdi);
 169         return &ii->vfs_inode;
 170 }
 171
 172 static void nilfs_i_callback(struct rcu_head *head)
 173 {
 174         struct inode *inode = container_of(head, struct inode, i_rcu);
 175         struct nilfs_mdt_info *mdi = NILFS_MDT(inode);
 176
 177         INIT_LIST_HEAD(&inode->i_dentry);
 178
 179         if (mdi) {
 180                 kfree(mdi->mi_bgl); /* kfree(NULL) is safe */
 181                 kfree(mdi);
 182         }
 183         kmem_cache_free(nilfs_inode_cachep, NILFS_I(inode));
 184 }
 185
 186 void nilfs_destroy_inode(struct inode *inode)
 187 {
 188         call_rcu(&inode->i_rcu, nilfs_i_callback);
 189 }
 190
 191 static int nilfs_sync_super(struct nilfs_sb_info *sbi, int flag)
 192 {
 193         struct the_nilfs *nilfs = sbi->s_nilfs;
 194         int err;
 195
 196  retry:
 197         set_buffer_dirty(nilfs->ns_sbh[0]);
 198         if (nilfs_test_opt(nilfs, BARRIER)) {
 199                 err = __sync_dirty_buffer(nilfs->ns_sbh[0],
 200                                           WRITE_SYNC | WRITE_FLUSH_FUA);
 201         } else {
 202                 err = sync_dirty_buffer(nilfs->ns_sbh[0]);
 203         }
 204
 205         if (unlikely(err)) {
 206                 printk(KERN_ERR
 207                        "NILFS: unable to write superblock (err=%d)\n", err);
 208                 if (err == -EIO && nilfs->ns_sbh[1]) {
 209                         /*
 210                          * sbp[0] points to newer log than sbp[1],
 211                          * so copy sbp[0] to sbp[1] to take over sbp[0].
 212                          */
 213                         memcpy(nilfs->ns_sbp[1], nilfs->ns_sbp[0],
 214                                nilfs->ns_sbsize);
 215                         nilfs_fall_back_super_block(nilfs);
 216                         goto retry;
 217                 }
 218         } else {
 219                 struct nilfs_super_block *sbp = nilfs->ns_sbp[0];
 220
 221                 nilfs->ns_sbwcount++;
 222
 223                 /*
 224                  * The latest segment becomes trailable from the position
 225                  * written in superblock.
 226                  */
 227                 clear_nilfs_discontinued(nilfs);
 228
 229                 /* update GC protection for recent segments */
 230                 if (nilfs->ns_sbh[1]) {
 231                         if (flag == NILFS_SB_COMMIT_ALL) {
 232                                 set_buffer_dirty(nilfs->ns_sbh[1]);
 233                                 if (sync_dirty_buffer(nilfs->ns_sbh[1]) < 0)
 234                                         goto out;
 235                         }
 236                         if (le64_to_cpu(nilfs->ns_sbp[1]->s_last_cno) <
 237                             le64_to_cpu(nilfs->ns_sbp[0]->s_last_cno))
 238                                 sbp = nilfs->ns_sbp[1];
 239                 }
 240
 241                 spin_lock(&nilfs->ns_last_segment_lock);
 242                 nilfs->ns_prot_seq = le64_to_cpu(sbp->s_last_seq);
 243                 spin_unlock(&nilfs->ns_last_segment_lock);
 244         }
 245  out:
 246         return err;
 247 }
 248
 249 void nilfs_set_log_cursor(struct nilfs_super_block *sbp,
 250                           struct the_nilfs *nilfs)
 251 {
 252         sector_t nfreeblocks;
 253
 254         /* nilfs->ns_sem must be locked by the caller. */
 255         nilfs_count_free_blocks(nilfs, &nfreeblocks);
 256         sbp->s_free_blocks_count = cpu_to_le64(nfreeblocks);
 257
 258         spin_lock(&nilfs->ns_last_segment_lock);
 259         sbp->s_last_seq = cpu_to_le64(nilfs->ns_last_seq);
 260         sbp->s_last_pseg = cpu_to_le64(nilfs->ns_last_pseg);
 261         sbp->s_last_cno = cpu_to_le64(nilfs->ns_last_cno);
 262         spin_unlock(&nilfs->ns_last_segment_lock);
 263 }
 264
 265 struct nilfs_super_block **nilfs_prepare_super(struct nilfs_sb_info *sbi,
 266                                                int flip)
 267 {
 268         struct the_nilfs *nilfs = sbi->s_nilfs;
 269         struct nilfs_super_block **sbp = nilfs->ns_sbp;
 270
 271         /* nilfs->ns_sem must be locked by the caller. */
 272         if (sbp[0]->s_magic != cpu_to_le16(NILFS_SUPER_MAGIC)) {
 273                 if (sbp[1] &&
 274                     sbp[1]->s_magic == cpu_to_le16(NILFS_SUPER_MAGIC)) {
 275                         memcpy(sbp[0], sbp[1], nilfs->ns_sbsize);
 276                 } else {
 277                         printk(KERN_CRIT "NILFS: superblock broke on dev %s\n",
 278                                sbi->s_super->s_id);
 279                         return NULL;
 280                 }
 281         } else if (sbp[1] &&
 282                    sbp[1]->s_magic != cpu_to_le16(NILFS_SUPER_MAGIC)) {
 283                         memcpy(sbp[1], sbp[0], nilfs->ns_sbsize);
 284         }
 285
 286         if (flip && sbp[1])
 287                 nilfs_swap_super_block(nilfs);
 288
 289         return sbp;
 290 }
 291
 292 int nilfs_commit_super(struct nilfs_sb_info *sbi, int flag)
 293 {
 294         struct the_nilfs *nilfs = sbi->s_nilfs;
 295         struct nilfs_super_block **sbp = nilfs->ns_sbp;
 296         time_t t;
 297
 298         /* nilfs->ns_sem must be locked by the caller. */
 299         t = get_seconds();
 300         nilfs->ns_sbwtime = t;
 301         sbp[0]->s_wtime = cpu_to_le64(t);
 302         sbp[0]->s_sum = 0;
 303         sbp[0]->s_sum = cpu_to_le32(crc32_le(nilfs->ns_crc_seed,
 304                                              (unsigned char *)sbp[0],
 305                                              nilfs->ns_sbsize));
 306         if (flag == NILFS_SB_COMMIT_ALL && sbp[1]) {
 307                 sbp[1]->s_wtime = sbp[0]->s_wtime;
 308                 sbp[1]->s_sum = 0;
 309                 sbp[1]->s_sum = cpu_to_le32(crc32_le(nilfs->ns_crc_seed,
 310                                             (unsigned char *)sbp[1],
 311                                             nilfs->ns_sbsize));
 312         }
 313         clear_nilfs_sb_dirty(nilfs);
 314         return nilfs_sync_super(sbi, flag);
 315 }
 316
 317 /**
 318  * nilfs_cleanup_super() - write filesystem state for cleanup
 319  * @sbi: nilfs_sb_info to be unmounted or degraded to read-only
 320  *
 321  * This function restores state flags in the on-disk super block.
 322  * This will set "clean" flag (i.e. NILFS_VALID_FS) unless the
 323  * filesystem was not clean previously.
 324  */
 325 int nilfs_cleanup_super(struct nilfs_sb_info *sbi)
 326 {
 327         struct nilfs_super_block **sbp;
 328         int flag = NILFS_SB_COMMIT;
 329         int ret = -EIO;
 330
 331         sbp = nilfs_prepare_super(sbi, 0);
 332         if (sbp) {
 333                 sbp[0]->s_state = cpu_to_le16(sbi->s_nilfs->ns_mount_state);
 334                 nilfs_set_log_cursor(sbp[0], sbi->s_nilfs);
 335                 if (sbp[1] && sbp[0]->s_last_cno == sbp[1]->s_last_cno) {
 336                         /*
 337                          * make the "clean" flag also to the opposite
 338                          * super block if both super blocks point to
 339                          * the same checkpoint.
 340                          */
 341                         sbp[1]->s_state = sbp[0]->s_state;
 342                         flag = NILFS_SB_COMMIT_ALL;
 343                 }
 344                 ret = nilfs_commit_super(sbi, flag);
 345         }
 346         return ret;
 347 }
 348
 349 static void nilfs_put_super(struct super_block *sb)
 350 {
 351         struct nilfs_sb_info *sbi = NILFS_SB(sb);
 352         struct the_nilfs *nilfs = sbi->s_nilfs;
 353
 354         nilfs_detach_segment_constructor(sbi);
 355
 356         if (!(sb->s_flags & MS_RDONLY)) {
 357                 down_write(&nilfs->ns_sem);
 358                 nilfs_cleanup_super(sbi);
 359                 up_write(&nilfs->ns_sem);
 360         }
 361
 362         iput(nilfs->ns_sufile);
 363         iput(nilfs->ns_cpfile);
 364         iput(nilfs->ns_dat);
 365
 366         destroy_nilfs(nilfs);
 367         sbi->s_super = NULL;
 368         sb->s_fs_info = NULL;
 369         kfree(sbi);
 370 }
 371
 372 static int nilfs_sync_fs(struct super_block *sb, int wait)
 373 {
 374         struct nilfs_sb_info *sbi = NILFS_SB(sb);
 375         struct the_nilfs *nilfs = sbi->s_nilfs;
 376         struct nilfs_super_block **sbp;
 377         int err = 0;
 378
 379         /* This function is called when super block should be written back */
 380         if (wait)
 381                 err = nilfs_construct_segment(sb);
 382
 383         down_write(&nilfs->ns_sem);
 384         if (nilfs_sb_dirty(nilfs)) {
 385                 sbp = nilfs_prepare_super(sbi, nilfs_sb_will_flip(nilfs));
 386                 if (likely(sbp)) {
 387                         nilfs_set_log_cursor(sbp[0], nilfs);
 388                         nilfs_commit_super(sbi, NILFS_SB_COMMIT);
 389                 }
 390         }
 391         up_write(&nilfs->ns_sem);
 392
 393         return err;
 394 }
 395
 396 int nilfs_attach_checkpoint(struct nilfs_sb_info *sbi, __u64 cno, int curr_mnt,
 397                             struct nilfs_root **rootp)
 398 {
 399         struct the_nilfs *nilfs = sbi->s_nilfs;
 400         struct nilfs_root *root;
 401         struct nilfs_checkpoint *raw_cp;
 402         struct buffer_head *bh_cp;
 403         int err = -ENOMEM;
 404
 405         root = nilfs_find_or_create_root(
 406                 nilfs, curr_mnt ? NILFS_CPTREE_CURRENT_CNO : cno);
 407         if (!root)
 408                 return err;
 409
 410         if (root->ifile)
 411                 goto reuse; /* already attached checkpoint */
 412
 413         down_read(&nilfs->ns_segctor_sem);
 414         err = nilfs_cpfile_get_checkpoint(nilfs->ns_cpfile, cno, 0, &raw_cp,
 415                                           &bh_cp);
 416         up_read(&nilfs->ns_segctor_sem);
 417         if (unlikely(err)) {
 418                 if (err == -ENOENT || err == -EINVAL) {
 419                         printk(KERN_ERR
 420                                "NILFS: Invalid checkpoint "
 421                                "(checkpoint number=%llu)\n",
 422                                (unsigned long long)cno);
 423                         err = -EINVAL;
 424                 }
 425                 goto failed;
 426         }
 427
 428         err = nilfs_ifile_read(sbi->s_super, root, nilfs->ns_inode_size,
 429                                &raw_cp->cp_ifile_inode, &root->ifile);
 430         if (err)
 431                 goto failed_bh;
 432
 433         atomic_set(&root->inodes_count, le64_to_cpu(raw_cp->cp_inodes_count));
 434         atomic_set(&root->blocks_count, le64_to_cpu(raw_cp->cp_blocks_count));
 435
 436         nilfs_cpfile_put_checkpoint(nilfs->ns_cpfile, cno, bh_cp);
 437
 438  reuse:
 439         *rootp = root;
 440         return 0;
 441
 442  failed_bh:
 443         nilfs_cpfile_put_checkpoint(nilfs->ns_cpfile, cno, bh_cp);
 444  failed:
 445         nilfs_put_root(root);
 446
 447         return err;
 448 }
 449
 450 static int nilfs_freeze(struct super_block *sb)
 451 {
 452         struct nilfs_sb_info *sbi = NILFS_SB(sb);
 453         struct the_nilfs *nilfs = sbi->s_nilfs;
 454         int err;
 455
 456         if (sb->s_flags & MS_RDONLY)
 457                 return 0;
 458
 459         /* Mark super block clean */
 460         down_write(&nilfs->ns_sem);
 461         err = nilfs_cleanup_super(sbi);
 462         up_write(&nilfs->ns_sem);
 463         return err;
 464 }
 465
 466 static int nilfs_unfreeze(struct super_block *sb)
 467 {
 468         struct nilfs_sb_info *sbi = NILFS_SB(sb);
 469         struct the_nilfs *nilfs = sbi->s_nilfs;
 470
 471         if (sb->s_flags & MS_RDONLY)
 472                 return 0;
 473
 474         down_write(&nilfs->ns_sem);
 475         nilfs_setup_super(sbi, false);
 476         up_write(&nilfs->ns_sem);
 477         return 0;
 478 }
 479
 480 static int nilfs_statfs(struct dentry *dentry, struct kstatfs *buf)
 481 {
 482         struct super_block *sb = dentry->d_sb;
 483         struct nilfs_root *root = NILFS_I(dentry->d_inode)->i_root;
 484         struct the_nilfs *nilfs = root->nilfs;
 485         u64 id = huge_encode_dev(sb->s_bdev->bd_dev);
 486         unsigned long long blocks;
 487         unsigned long overhead;
 488         unsigned long nrsvblocks;
 489         sector_t nfreeblocks;
 490         int err;
 491
 492         /*
 493          * Compute all of the segment blocks
 494          *
 495          * The blocks before first segment and after last segment
 496          * are excluded.
 497          */
 498         blocks = nilfs->ns_blocks_per_segment * nilfs->ns_nsegments
 499                 - nilfs->ns_first_data_block;
 500         nrsvblocks = nilfs->ns_nrsvsegs * nilfs->ns_blocks_per_segment;
 501
 502         /*
 503          * Compute the overhead
 504          *
 505          * When distributing meta data blocks outside segment structure,
 506          * We must count them as the overhead.
 507          */
 508         overhead = 0;
 509
 510         err = nilfs_count_free_blocks(nilfs, &nfreeblocks);
 511         if (unlikely(err))
 512                 return err;
 513
 514         buf->f_type = NILFS_SUPER_MAGIC;
 515         buf->f_bsize = sb->s_blocksize;
 516         buf->f_blocks = blocks - overhead;
 517         buf->f_bfree = nfreeblocks;
 518         buf->f_bavail = (buf->f_bfree >= nrsvblocks) ?
 519                 (buf->f_bfree - nrsvblocks) : 0;
 520         buf->f_files = atomic_read(&root->inodes_count);
 521         buf->f_ffree = 0; /* nilfs_count_free_inodes(sb); */
 522         buf->f_namelen = NILFS_NAME_LEN;
 523         buf->f_fsid.val[0] = (u32)id;
 524         buf->f_fsid.val[1] = (u32)(id >> 32);
 525
 526         return 0;
 527 }
 528
 529 static int nilfs_show_options(struct seq_file *seq, struct vfsmount *vfs)
 530 {
 531         struct super_block *sb = vfs->mnt_sb;
 532         struct the_nilfs *nilfs = NILFS_SB(sb)->s_nilfs;
 533         struct nilfs_root *root = NILFS_I(vfs->mnt_root->d_inode)->i_root;
 534
 535         if (!nilfs_test_opt(nilfs, BARRIER))
 536                 seq_puts(seq, ",nobarrier");
 537         if (root->cno != NILFS_CPTREE_CURRENT_CNO)
 538                 seq_printf(seq, ",cp=%llu", (unsigned long long)root->cno);
 539         if (nilfs_test_opt(nilfs, ERRORS_PANIC))
 540                 seq_puts(seq, ",errors=panic");
 541         if (nilfs_test_opt(nilfs, ERRORS_CONT))
 542                 seq_puts(seq, ",errors=continue");
 543         if (nilfs_test_opt(nilfs, STRICT_ORDER))
 544                 seq_puts(seq, ",order=strict");
 545         if (nilfs_test_opt(nilfs, NORECOVERY))
 546                 seq_puts(seq, ",norecovery");
 547         if (nilfs_test_opt(nilfs, DISCARD))
 548                 seq_puts(seq, ",discard");
 549
 550         return 0;
 551 }
 552
 553 static const struct super_operations nilfs_sops = {
 554         .alloc_inode    = nilfs_alloc_inode,
 555         .destroy_inode  = nilfs_destroy_inode,
 556         .dirty_inode    = nilfs_dirty_inode,
 557         /* .write_inode    = nilfs_write_inode, */
 558         /* .put_inode      = nilfs_put_inode, */
 559         /* .drop_inode    = nilfs_drop_inode, */
 560         .evict_inode    = nilfs_evict_inode,
 561         .put_super      = nilfs_put_super,
 562         /* .write_super    = nilfs_write_super, */
 563         .sync_fs        = nilfs_sync_fs,
 564         .freeze_fs      = nilfs_freeze,
 565         .unfreeze_fs    = nilfs_unfreeze,
 566         /* .write_super_lockfs */
 567         /* .unlockfs */
 568         .statfs         = nilfs_statfs,
 569         .remount_fs     = nilfs_remount,
 570         /* .umount_begin */
 571         .show_options = nilfs_show_options
 572 };
 573
 574 enum {
 575         Opt_err_cont, Opt_err_panic, Opt_err_ro,
 576         Opt_barrier, Opt_nobarrier, Opt_snapshot, Opt_order, Opt_norecovery,
 577         Opt_discard, Opt_nodiscard, Opt_err,
 578 };
 579
 580 static match_table_t tokens = {
 581         {Opt_err_cont, "errors=continue"},
 582         {Opt_err_panic, "errors=panic"},
 583         {Opt_err_ro, "errors=remount-ro"},
 584         {Opt_barrier, "barrier"},
 585         {Opt_nobarrier, "nobarrier"},
 586         {Opt_snapshot, "cp=%u"},
 587         {Opt_order, "order=%s"},
 588         {Opt_norecovery, "norecovery"},
 589         {Opt_discard, "discard"},
 590         {Opt_nodiscard, "nodiscard"},
 591         {Opt_err, NULL}
 592 };
 593
 594 static int parse_options(char *options, struct super_block *sb, int is_remount)
 595 {
 596         struct the_nilfs *nilfs = NILFS_SB(sb)->s_nilfs;
 597         char *p;
 598         substring_t args[MAX_OPT_ARGS];
 599
 600         if (!options)
 601                 return 1;
 602
 603         while ((p = strsep(&options, ",")) != NULL) {
 604                 int token;
 605                 if (!*p)
 606                         continue;
 607
 608                 token = match_token(p, tokens, args);
 609                 switch (token) {
 610                 case Opt_barrier:
 611                         nilfs_set_opt(nilfs, BARRIER);
 612                         break;
 613                 case Opt_nobarrier:
 614                         nilfs_clear_opt(nilfs, BARRIER);
 615                         break;
 616                 case Opt_order:
 617                         if (strcmp(args[0].from, "relaxed") == 0)
 618                                 /* Ordered data semantics */
 619                                 nilfs_clear_opt(nilfs, STRICT_ORDER);
 620                         else if (strcmp(args[0].from, "strict") == 0)
 621                                 /* Strict in-order semantics */
 622                                 nilfs_set_opt(nilfs, STRICT_ORDER);
 623                         else
 624                                 return 0;
 625                         break;
 626                 case Opt_err_panic:
 627                         nilfs_write_opt(nilfs, ERROR_MODE, ERRORS_PANIC);
 628                         break;
 629                 case Opt_err_ro:
 630                         nilfs_write_opt(nilfs, ERROR_MODE, ERRORS_RO);
 631                         break;
 632                 case Opt_err_cont:
 633                         nilfs_write_opt(nilfs, ERROR_MODE, ERRORS_CONT);
 634                         break;
 635                 case Opt_snapshot:
 636                         if (is_remount) {
 637                                 printk(KERN_ERR
 638                                        "NILFS: \"%s\" option is invalid "
 639                                        "for remount.\n", p);
 640                                 return 0;
 641                         }
 642                         break;
 643                 case Opt_norecovery:
 644                         nilfs_set_opt(nilfs, NORECOVERY);
 645                         break;
 646                 case Opt_discard:
 647                         nilfs_set_opt(nilfs, DISCARD);
 648                         break;
 649                 case Opt_nodiscard:
 650                         nilfs_clear_opt(nilfs, DISCARD);
 651                         break;
 652                 default:
 653                         printk(KERN_ERR
 654                                "NILFS: Unrecognized mount option \"%s\"\n", p);
 655                         return 0;
 656                 }
 657         }
 658         return 1;
 659 }
 660
 661 static inline void
 662 nilfs_set_default_options(struct super_block *sb,
 663                           struct nilfs_super_block *sbp)
 664 {
 665         struct the_nilfs *nilfs = NILFS_SB(sb)->s_nilfs;
 666
 667         nilfs->ns_mount_opt =
 668                 NILFS_MOUNT_ERRORS_RO | NILFS_MOUNT_BARRIER;
 669 }
 670
 671 static int nilfs_setup_super(struct nilfs_sb_info *sbi, int is_mount)
 672 {
 673         struct the_nilfs *nilfs = sbi->s_nilfs;
 674         struct nilfs_super_block **sbp;
 675         int max_mnt_count;
 676         int mnt_count;
 677
 678         /* nilfs->ns_sem must be locked by the caller. */
 679         sbp = nilfs_prepare_super(sbi, 0);
 680         if (!sbp)
 681                 return -EIO;
 682
 683         if (!is_mount)
 684                 goto skip_mount_setup;
 685
 686         max_mnt_count = le16_to_cpu(sbp[0]->s_max_mnt_count);
 687         mnt_count = le16_to_cpu(sbp[0]->s_mnt_count);
 688
 689         if (nilfs->ns_mount_state & NILFS_ERROR_FS) {
 690                 printk(KERN_WARNING
 691                        "NILFS warning: mounting fs with errors\n");
 692 #if 0
 693         } else if (max_mnt_count >= 0 && mnt_count >= max_mnt_count) {
 694                 printk(KERN_WARNING
 695                        "NILFS warning: maximal mount count reached\n");
 696 #endif
 697         }
 698         if (!max_mnt_count)
 699                 sbp[0]->s_max_mnt_count = cpu_to_le16(NILFS_DFL_MAX_MNT_COUNT);
 700
 701         sbp[0]->s_mnt_count = cpu_to_le16(mnt_count + 1);
 702         sbp[0]->s_mtime = cpu_to_le64(get_seconds());
 703
 704 skip_mount_setup:
 705         sbp[0]->s_state =
 706                 cpu_to_le16(le16_to_cpu(sbp[0]->s_state) & ~NILFS_VALID_FS);
 707         /* synchronize sbp[1] with sbp[0] */
 708         if (sbp[1])
 709                 memcpy(sbp[1], sbp[0], nilfs->ns_sbsize);
 710         return nilfs_commit_super(sbi, NILFS_SB_COMMIT_ALL);
 711 }
 712
 713 struct nilfs_super_block *nilfs_read_super_block(struct super_block *sb,
 714                                                  u64 pos, int blocksize,
 715                                                  struct buffer_head **pbh)
 716 {
 717         unsigned long long sb_index = pos;
 718         unsigned long offset;
 719
 720         offset = do_div(sb_index, blocksize);
 721         *pbh = sb_bread(sb, sb_index);
 722         if (!*pbh)
 723                 return NULL;
 724         return (struct nilfs_super_block *)((char *)(*pbh)->b_data + offset);
 725 }
 726
 727 int nilfs_store_magic_and_option(struct super_block *sb,
 728                                  struct nilfs_super_block *sbp,
 729                                  char *data)
 730 {
 731         struct the_nilfs *nilfs = NILFS_SB(sb)->s_nilfs;
 732
 733         sb->s_magic = le16_to_cpu(sbp->s_magic);
 734
 735         /* FS independent flags */
 736 #ifdef NILFS_ATIME_DISABLE
 737         sb->s_flags |= MS_NOATIME;
 738 #endif
 739
 740         nilfs_set_default_options(sb, sbp);
 741
 742         nilfs->ns_resuid = le16_to_cpu(sbp->s_def_resuid);
 743         nilfs->ns_resgid = le16_to_cpu(sbp->s_def_resgid);
 744         nilfs->ns_interval = le32_to_cpu(sbp->s_c_interval);
 745         nilfs->ns_watermark = le32_to_cpu(sbp->s_c_block_max);
 746
 747         return !parse_options(data, sb, 0) ? -EINVAL : 0 ;
 748 }
 749
 750 int nilfs_check_feature_compatibility(struct super_block *sb,
 751                                       struct nilfs_super_block *sbp)
 752 {
 753         __u64 features;
 754
 755         features = le64_to_cpu(sbp->s_feature_incompat) &
 756                 ~NILFS_FEATURE_INCOMPAT_SUPP;
 757         if (features) {
 758                 printk(KERN_ERR "NILFS: couldn't mount because of unsupported "
 759                        "optional features (%llx)\n",
 760                        (unsigned long long)features);
 761                 return -EINVAL;
 762         }
 763         features = le64_to_cpu(sbp->s_feature_compat_ro) &
 764                 ~NILFS_FEATURE_COMPAT_RO_SUPP;
 765         if (!(sb->s_flags & MS_RDONLY) && features) {
 766                 printk(KERN_ERR "NILFS: couldn't mount RDWR because of "
 767                        "unsupported optional features (%llx)\n",
 768                        (unsigned long long)features);
 769                 return -EINVAL;
 770         }
 771         return 0;
 772 }
 773
 774 static int nilfs_get_root_dentry(struct super_block *sb,
 775                                  struct nilfs_root *root,
 776                                  struct dentry **root_dentry)
 777 {
 778         struct inode *inode;
 779         struct dentry *dentry;
 780         int ret = 0;
 781
 782         inode = nilfs_iget(sb, root, NILFS_ROOT_INO);
 783         if (IS_ERR(inode)) {
 784                 printk(KERN_ERR "NILFS: get root inode failed\n");
 785                 ret = PTR_ERR(inode);
 786                 goto out;
 787         }
 788         if (!S_ISDIR(inode->i_mode) || !inode->i_blocks || !inode->i_size) {
 789                 iput(inode);
 790                 printk(KERN_ERR "NILFS: corrupt root inode.\n");
 791                 ret = -EINVAL;
 792                 goto out;
 793         }
 794
 795         if (root->cno == NILFS_CPTREE_CURRENT_CNO) {
 796                 dentry = d_find_alias(inode);
 797                 if (!dentry) {
 798                         dentry = d_alloc_root(inode);
 799                         if (!dentry) {
 800                                 iput(inode);
 801                                 ret = -ENOMEM;
 802                                 goto failed_dentry;
 803                         }
 804                 } else {
 805                         iput(inode);
 806                 }
 807         } else {
 808                 dentry = d_obtain_alias(inode);
 809                 if (IS_ERR(dentry)) {
 810                         ret = PTR_ERR(dentry);
 811                         goto failed_dentry;
 812                 }
 813         }
 814         *root_dentry = dentry;
 815  out:
 816         return ret;
 817
 818  failed_dentry:
 819         printk(KERN_ERR "NILFS: get root dentry failed\n");
 820         goto out;
 821 }
 822
 823 static int nilfs_attach_snapshot(struct super_block *s, __u64 cno,
 824                                  struct dentry **root_dentry)
 825 {
 826         struct the_nilfs *nilfs = NILFS_SB(s)->s_nilfs;
 827         struct nilfs_root *root;
 828         int ret;
 829
 830         down_read(&nilfs->ns_segctor_sem);
 831         ret = nilfs_cpfile_is_snapshot(nilfs->ns_cpfile, cno);
 832         up_read(&nilfs->ns_segctor_sem);
 833         if (ret < 0) {
 834                 ret = (ret == -ENOENT) ? -EINVAL : ret;
 835                 goto out;
 836         } else if (!ret) {
 837                 printk(KERN_ERR "NILFS: The specified checkpoint is "
 838                        "not a snapshot (checkpoint number=%llu).\n",
 839                        (unsigned long long)cno);
 840                 ret = -EINVAL;
 841                 goto out;
 842         }
 843
 844         ret = nilfs_attach_checkpoint(NILFS_SB(s), cno, false, &root);
 845         if (ret) {
 846                 printk(KERN_ERR "NILFS: error loading snapshot "
 847                        "(checkpoint number=%llu).\n",
 848                (unsigned long long)cno);
 849                 goto out;
 850         }
 851         ret = nilfs_get_root_dentry(s, root, root_dentry);
 852         nilfs_put_root(root);
 853  out:
 854         return ret;
 855 }
 856
 857 static int nilfs_tree_was_touched(struct dentry *root_dentry)
 858 {
 859         return root_dentry->d_count > 1;
 860 }
 861
 862 /**
 863  * nilfs_try_to_shrink_tree() - try to shrink dentries of a checkpoint
 864  * @root_dentry: root dentry of the tree to be shrunk
 865  *
 866  * This function returns true if the tree was in-use.
 867  */
 868 static int nilfs_try_to_shrink_tree(struct dentry *root_dentry)
 869 {
 870         if (have_submounts(root_dentry))
 871                 return true;
 872         shrink_dcache_parent(root_dentry);
 873         return nilfs_tree_was_touched(root_dentry);
 874 }
 875
 876 int nilfs_checkpoint_is_mounted(struct super_block *sb, __u64 cno)
 877 {
 878         struct the_nilfs *nilfs = NILFS_SB(sb)->s_nilfs;
 879         struct nilfs_root *root;
 880         struct inode *inode;
 881         struct dentry *dentry;
 882         int ret;
 883
 884         if (cno < 0 || cno > nilfs->ns_cno)
 885                 return false;
 886
 887         if (cno >= nilfs_last_cno(nilfs))
 888                 return true;    /* protect recent checkpoints */
 889
 890         ret = false;
 891         root = nilfs_lookup_root(NILFS_SB(sb)->s_nilfs, cno);
 892         if (root) {
 893                 inode = nilfs_ilookup(sb, root, NILFS_ROOT_INO);
 894                 if (inode) {
 895                         dentry = d_find_alias(inode);
 896                         if (dentry) {
 897                                 if (nilfs_tree_was_touched(dentry))
 898                                         ret = nilfs_try_to_shrink_tree(dentry);
 899                                 dput(dentry);
 900                         }
 901                         iput(inode);
 902                 }
 903                 nilfs_put_root(root);
 904         }
 905         return ret;
 906 }
 907
 908 /**
 909  * nilfs_fill_super() - initialize a super block instance
 910  * @sb: super_block
 911  * @data: mount options
 912  * @silent: silent mode flag
 913  *
 914  * This function is called exclusively by nilfs->ns_mount_mutex.
 915  * So, the recovery process is protected from other simultaneous mounts.
 916  */
 917 static int
 918 nilfs_fill_super(struct super_block *sb, void *data, int silent)
 919 {
 920         struct the_nilfs *nilfs;
 921         struct nilfs_sb_info *sbi;
 922         struct nilfs_root *fsroot;
 923         struct backing_dev_info *bdi;
 924         __u64 cno;
 925         int err;
 926
 927         sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
 928         if (!sbi)
 929                 return -ENOMEM;
 930
 931         sb->s_fs_info = sbi;
 932         sbi->s_super = sb;
 933
 934         nilfs = alloc_nilfs(sb->s_bdev);
 935         if (!nilfs) {
 936                 err = -ENOMEM;
 937                 goto failed_sbi;
 938         }
 939         sbi->s_nilfs = nilfs;
 940
 941         err = init_nilfs(nilfs, sbi, (char *)data);
 942         if (err)
 943                 goto failed_nilfs;
 944
 945         sb->s_op = &nilfs_sops;
 946         sb->s_export_op = &nilfs_export_ops;
 947         sb->s_root = NULL;
 948         sb->s_time_gran = 1;
 949
 950         bdi = sb->s_bdev->bd_inode->i_mapping->backing_dev_info;
 951         sb->s_bdi = bdi ? : &default_backing_dev_info;
 952
 953         err = load_nilfs(nilfs, sbi);
 954         if (err)
 955                 goto failed_nilfs;
 956
 957         cno = nilfs_last_cno(nilfs);
 958         err = nilfs_attach_checkpoint(sbi, cno, true, &fsroot);
 959         if (err) {
 960                 printk(KERN_ERR "NILFS: error loading last checkpoint "
 961                        "(checkpoint number=%llu).\n", (unsigned long long)cno);
 962                 goto failed_unload;
 963         }
 964
 965         if (!(sb->s_flags & MS_RDONLY)) {
 966                 err = nilfs_attach_segment_constructor(sbi, fsroot);
 967                 if (err)
 968                         goto failed_checkpoint;
 969         }
 970
 971         err = nilfs_get_root_dentry(sb, fsroot, &sb->s_root);
 972         if (err)
 973                 goto failed_segctor;
 974
 975         nilfs_put_root(fsroot);
 976
 977         if (!(sb->s_flags & MS_RDONLY)) {
 978                 down_write(&nilfs->ns_sem);
 979                 nilfs_setup_super(sbi, true);
 980                 up_write(&nilfs->ns_sem);
 981         }
 982
 983         return 0;
 984
 985  failed_segctor:
 986         nilfs_detach_segment_constructor(sbi);
 987
 988  failed_checkpoint:
 989         nilfs_put_root(fsroot);
 990
 991  failed_unload:
 992         iput(nilfs->ns_sufile);
 993         iput(nilfs->ns_cpfile);
 994         iput(nilfs->ns_dat);
 995
 996  failed_nilfs:
 997         destroy_nilfs(nilfs);
 998
 999  failed_sbi:
1000         sb->s_fs_info = NULL;
1001         kfree(sbi);
1002         return err;
1003 }
1004
1005 static int nilfs_remount(struct super_block *sb, int *flags, char *data)
1006 {
1007         struct nilfs_sb_info *sbi = NILFS_SB(sb);
1008         struct the_nilfs *nilfs = sbi->s_nilfs;
1009         unsigned long old_sb_flags;
1010         unsigned long old_mount_opt;
1011         int err;
1012
1013         old_sb_flags = sb->s_flags;
1014         old_mount_opt = nilfs->ns_mount_opt;
1015
1016         if (!parse_options(data, sb, 1)) {
1017                 err = -EINVAL;
1018                 goto restore_opts;
1019         }
1020         sb->s_flags = (sb->s_flags & ~MS_POSIXACL);
1021
1022         err = -EINVAL;
1023
1024         if (!nilfs_valid_fs(nilfs)) {
1025                 printk(KERN_WARNING "NILFS (device %s): couldn't "
1026                        "remount because the filesystem is in an "
1027                        "incomplete recovery state.\n", sb->s_id);
1028                 goto restore_opts;
1029         }
1030
1031         if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY))
1032                 goto out;
1033         if (*flags & MS_RDONLY) {
1034                 /* Shutting down the segment constructor */
1035                 nilfs_detach_segment_constructor(sbi);
1036                 sb->s_flags |= MS_RDONLY;
1037
1038                 /*
1039                  * Remounting a valid RW partition RDONLY, so set
1040                  * the RDONLY flag and then mark the partition as valid again.
1041                  */
1042                 down_write(&nilfs->ns_sem);
1043                 nilfs_cleanup_super(sbi);
1044                 up_write(&nilfs->ns_sem);
1045         } else {
1046                 __u64 features;
1047                 struct nilfs_root *root;
1048
1049                 /*
1050                  * Mounting a RDONLY partition read-write, so reread and
1051                  * store the current valid flag.  (It may have been changed
1052                  * by fsck since we originally mounted the partition.)
1053                  */
1054                 down_read(&nilfs->ns_sem);
1055                 features = le64_to_cpu(nilfs->ns_sbp[0]->s_feature_compat_ro) &
1056                         ~NILFS_FEATURE_COMPAT_RO_SUPP;
1057                 up_read(&nilfs->ns_sem);
1058                 if (features) {
1059                         printk(KERN_WARNING "NILFS (device %s): couldn't "
1060                                "remount RDWR because of unsupported optional "
1061                                "features (%llx)\n",
1062                                sb->s_id, (unsigned long long)features);
1063                         err = -EROFS;
1064                         goto restore_opts;
1065                 }
1066
1067                 sb->s_flags &= ~MS_RDONLY;
1068
1069                 root = NILFS_I(sb->s_root->d_inode)->i_root;
1070                 err = nilfs_attach_segment_constructor(sbi, root);
1071                 if (err)
1072                         goto restore_opts;
1073
1074                 down_write(&nilfs->ns_sem);
1075                 nilfs_setup_super(sbi, true);
1076                 up_write(&nilfs->ns_sem);
1077         }
1078  out:
1079         return 0;
1080
1081  restore_opts:
1082         sb->s_flags = old_sb_flags;
1083         nilfs->ns_mount_opt = old_mount_opt;
1084         return err;
1085 }
1086
1087 struct nilfs_super_data {
1088         struct block_device *bdev;
1089         struct nilfs_sb_info *sbi;
1090         __u64 cno;
1091         int flags;
1092 };
1093
1094 /**
1095  * nilfs_identify - pre-read mount options needed to identify mount instance
1096  * @data: mount options
1097  * @sd: nilfs_super_data
1098  */
1099 static int nilfs_identify(char *data, struct nilfs_super_data *sd)
1100 {
1101         char *p, *options = data;
1102         substring_t args[MAX_OPT_ARGS];
1103         int token;
1104         int ret = 0;
1105
1106         do {
1107                 p = strsep(&options, ",");
1108                 if (p != NULL && *p) {
1109                         token = match_token(p, tokens, args);
1110                         if (token == Opt_snapshot) {
1111                                 if (!(sd->flags & MS_RDONLY)) {
1112                                         ret++;
1113                                 } else {
1114                                         sd->cno = simple_strtoull(args[0].from,
1115                                                                   NULL, 0);
1116                                         /*
1117                                          * No need to see the end pointer;
1118                                          * match_token() has done syntax
1119                                          * checking.
1120                                          */
1121                                         if (sd->cno == 0)
1122                                                 ret++;
1123                                 }
1124                         }
1125                         if (ret)
1126                                 printk(KERN_ERR
1127                                        "NILFS: invalid mount option: %s\n", p);
1128                 }
1129                 if (!options)
1130                         break;
1131                 BUG_ON(options == data);
1132                 *(options - 1) = ',';
1133         } while (!ret);
1134         return ret;
1135 }
1136
1137 static int nilfs_set_bdev_super(struct super_block *s, void *data)
1138 {
1139         s->s_bdev = data;
1140         s->s_dev = s->s_bdev->bd_dev;
1141         return 0;
1142 }
1143
1144 static int nilfs_test_bdev_super(struct super_block *s, void *data)
1145 {
1146         return (void *)s->s_bdev == data;
1147 }
1148
1149 static struct dentry *
1150 nilfs_mount(struct file_system_type *fs_type, int flags,
1151              const char *dev_name, void *data)
1152 {
1153         struct nilfs_super_data sd;
1154         struct super_block *s;
1155         fmode_t mode = FMODE_READ | FMODE_EXCL;
1156         struct dentry *root_dentry;
1157         int err, s_new = false;
1158
1159         if (!(flags & MS_RDONLY))
1160                 mode |= FMODE_WRITE;
1161
1162         sd.bdev = blkdev_get_by_path(dev_name, mode, fs_type);
1163         if (IS_ERR(sd.bdev))
1164                 return ERR_CAST(sd.bdev);
1165
1166         sd.cno = 0;
1167         sd.flags = flags;
1168         if (nilfs_identify((char *)data, &sd)) {
1169                 err = -EINVAL;
1170                 goto failed;
1171         }
1172
1173         /*
1174          * once the super is inserted into the list by sget, s_umount
1175          * will protect the lockfs code from trying to start a snapshot
1176          * while we are mounting
1177          */
1178         mutex_lock(&sd.bdev->bd_fsfreeze_mutex);
1179         if (sd.bdev->bd_fsfreeze_count > 0) {
1180                 mutex_unlock(&sd.bdev->bd_fsfreeze_mutex);
1181                 err = -EBUSY;
1182                 goto failed;
1183         }
1184         s = sget(fs_type, nilfs_test_bdev_super, nilfs_set_bdev_super, sd.bdev);
1185         mutex_unlock(&sd.bdev->bd_fsfreeze_mutex);
1186         if (IS_ERR(s)) {
1187                 err = PTR_ERR(s);
1188                 goto failed;
1189         }
1190
1191         if (!s->s_root) {
1192                 char b[BDEVNAME_SIZE];
1193
1194                 s_new = true;
1195
1196                 /* New superblock instance created */
1197                 s->s_flags = flags;
1198                 s->s_mode = mode;
1199                 strlcpy(s->s_id, bdevname(sd.bdev, b), sizeof(s->s_id));
1200                 sb_set_blocksize(s, block_size(sd.bdev));
1201
1202                 err = nilfs_fill_super(s, data, flags & MS_SILENT ? 1 : 0);
1203                 if (err)
1204                         goto failed_super;
1205
1206                 s->s_flags |= MS_ACTIVE;
1207         } else if (!sd.cno) {
1208                 int busy = false;
1209
1210                 if (nilfs_tree_was_touched(s->s_root)) {
1211                         busy = nilfs_try_to_shrink_tree(s->s_root);
1212                         if (busy && (flags ^ s->s_flags) & MS_RDONLY) {
1213                                 printk(KERN_ERR "NILFS: the device already "
1214                                        "has a %s mount.\n",
1215                                        (s->s_flags & MS_RDONLY) ?
1216                                        "read-only" : "read/write");
1217                                 err = -EBUSY;
1218                                 goto failed_super;
1219                         }
1220                 }
1221                 if (!busy) {
1222                         /*
1223                          * Try remount to setup mount states if the current
1224                          * tree is not mounted and only snapshots use this sb.
1225                          */
1226                         err = nilfs_remount(s, &flags, data);
1227                         if (err)
1228                                 goto failed_super;
1229                 }
1230         }
1231
1232         if (sd.cno) {
1233                 err = nilfs_attach_snapshot(s, sd.cno, &root_dentry);
1234                 if (err)
1235                         goto failed_super;
1236         } else {
1237                 root_dentry = dget(s->s_root);
1238         }
1239
1240         if (!s_new)
1241                 blkdev_put(sd.bdev, mode);
1242
1243         return root_dentry;
1244
1245  failed_super:
1246         deactivate_locked_super(s);
1247
1248  failed:
1249         if (!s_new)
1250                 blkdev_put(sd.bdev, mode);
1251         return ERR_PTR(err);
1252 }
1253
1254 struct file_system_type nilfs_fs_type = {
1255         .owner    = THIS_MODULE,
1256         .name     = "nilfs2",
1257         .mount    = nilfs_mount,
1258         .kill_sb  = kill_block_super,
1259         .fs_flags = FS_REQUIRES_DEV,
1260 };
1261
1262 static void nilfs_inode_init_once(void *obj)
1263 {
1264         struct nilfs_inode_info *ii = obj;
1265
1266         INIT_LIST_HEAD(&ii->i_dirty);
1267 #ifdef CONFIG_NILFS_XATTR
1268         init_rwsem(&ii->xattr_sem);
1269 #endif
1270         address_space_init_once(&ii->i_btnode_cache);
1271         ii->i_bmap = &ii->i_bmap_data;
1272         inode_init_once(&ii->vfs_inode);
1273 }
1274
1275 static void nilfs_segbuf_init_once(void *obj)
1276 {
1277         memset(obj, 0, sizeof(struct nilfs_segment_buffer));
1278 }
1279
1280 static void nilfs_destroy_cachep(void)
1281 {
1282         if (nilfs_inode_cachep)
1283                 kmem_cache_destroy(nilfs_inode_cachep);
1284         if (nilfs_transaction_cachep)
1285                 kmem_cache_destroy(nilfs_transaction_cachep);
1286         if (nilfs_segbuf_cachep)
1287                 kmem_cache_destroy(nilfs_segbuf_cachep);
1288         if (nilfs_btree_path_cache)
1289                 kmem_cache_destroy(nilfs_btree_path_cache);
1290 }
1291
1292 static int __init nilfs_init_cachep(void)
1293 {
1294         nilfs_inode_cachep = kmem_cache_create("nilfs2_inode_cache",
1295                         sizeof(struct nilfs_inode_info), 0,
1296                         SLAB_RECLAIM_ACCOUNT, nilfs_inode_init_once);
1297         if (!nilfs_inode_cachep)
1298                 goto fail;
1299
1300         nilfs_transaction_cachep = kmem_cache_create("nilfs2_transaction_cache",
1301                         sizeof(struct nilfs_transaction_info), 0,
1302                         SLAB_RECLAIM_ACCOUNT, NULL);
1303         if (!nilfs_transaction_cachep)
1304                 goto fail;
1305
1306         nilfs_segbuf_cachep = kmem_cache_create("nilfs2_segbuf_cache",
1307                         sizeof(struct nilfs_segment_buffer), 0,
1308                         SLAB_RECLAIM_ACCOUNT, nilfs_segbuf_init_once);
1309         if (!nilfs_segbuf_cachep)
1310                 goto fail;
1311
1312         nilfs_btree_path_cache = kmem_cache_create("nilfs2_btree_path_cache",
1313                         sizeof(struct nilfs_btree_path) * NILFS_BTREE_LEVEL_MAX,
1314                         0, 0, NULL);
1315         if (!nilfs_btree_path_cache)
1316                 goto fail;
1317
1318         return 0;
1319
1320 fail:
1321         nilfs_destroy_cachep();
1322         return -ENOMEM;
1323 }
1324
1325 static int __init init_nilfs_fs(void)
1326 {
1327         int err;
1328
1329         err = nilfs_init_cachep();
1330         if (err)
1331                 goto fail;
1332
1333         err = register_filesystem(&nilfs_fs_type);
1334         if (err)
1335                 goto free_cachep;
1336
1337         printk(KERN_INFO "NILFS version 2 loaded\n");
1338         return 0;
1339
1340 free_cachep:
1341         nilfs_destroy_cachep();
1342 fail:
1343         return err;
1344 }
1345
1346 static void __exit exit_nilfs_fs(void)
1347 {
1348         nilfs_destroy_cachep();
1349         unregister_filesystem(&nilfs_fs_type);
1350 }
1351
1352 module_init(init_nilfs_fs)
1353 module_exit(exit_nilfs_fs)