fs/xfs/xfs_mount.c

   1 /*
   2  * Copyright (c) 2000-2005 Silicon Graphics, Inc.
   3  * All Rights Reserved.
   4  *
   5  * This program is free software; you can redistribute it and/or
   6  * modify it under the terms of the GNU General Public License as
   7  * published by the Free Software Foundation.
   8  *
   9  * This program is distributed in the hope that it would be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program; if not, write the Free Software Foundation,
  16  * Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  17  */
  18 #include "xfs.h"
  19 #include "xfs_fs.h"
  20 #include "xfs_types.h"
  21 #include "xfs_bit.h"
  22 #include "xfs_log.h"
  23 #include "xfs_inum.h"
  24 #include "xfs_trans.h"
  25 #include "xfs_sb.h"
  26 #include "xfs_ag.h"
  27 #include "xfs_dir2.h"
  28 #include "xfs_dmapi.h"
  29 #include "xfs_mount.h"
  30 #include "xfs_bmap_btree.h"
  31 #include "xfs_alloc_btree.h"
  32 #include "xfs_ialloc_btree.h"
  33 #include "xfs_dir2_sf.h"
  34 #include "xfs_attr_sf.h"
  35 #include "xfs_dinode.h"
  36 #include "xfs_inode.h"
  37 #include "xfs_btree.h"
  38 #include "xfs_ialloc.h"
  39 #include "xfs_alloc.h"
  40 #include "xfs_rtalloc.h"
  41 #include "xfs_bmap.h"
  42 #include "xfs_error.h"
  43 #include "xfs_rw.h"
  44 #include "xfs_quota.h"
  45 #include "xfs_fsops.h"
  46
  47 STATIC void     xfs_mount_log_sbunit(xfs_mount_t *, __int64_t);
  48 STATIC int      xfs_uuid_mount(xfs_mount_t *);
  49 STATIC void     xfs_uuid_unmount(xfs_mount_t *mp);
  50 STATIC void     xfs_unmountfs_wait(xfs_mount_t *);
  51
  52
  53 #ifdef HAVE_PERCPU_SB
  54 STATIC void     xfs_icsb_destroy_counters(xfs_mount_t *);
  55 STATIC void     xfs_icsb_balance_counter(xfs_mount_t *, xfs_sb_field_t,
  56                                                 int, int);
  57 STATIC void     xfs_icsb_sync_counters(xfs_mount_t *);
  58 STATIC int      xfs_icsb_modify_counters(xfs_mount_t *, xfs_sb_field_t,
  59                                                 int64_t, int);
  60 STATIC int      xfs_icsb_disable_counter(xfs_mount_t *, xfs_sb_field_t);
  61
  62 #else
  63
  64 #define xfs_icsb_destroy_counters(mp)                   do { } while (0)
  65 #define xfs_icsb_balance_counter(mp, a, b, c)           do { } while (0)
  66 #define xfs_icsb_sync_counters(mp)                      do { } while (0)
  67 #define xfs_icsb_modify_counters(mp, a, b, c)           do { } while (0)
  68
  69 #endif
  70
  71 static const struct {
  72         short offset;
  73         short type;     /* 0 = integer
  74                          * 1 = binary / string (no translation)
  75                          */
  76 } xfs_sb_info[] = {
  77     { offsetof(xfs_sb_t, sb_magicnum),   0 },
  78     { offsetof(xfs_sb_t, sb_blocksize),  0 },
  79     { offsetof(xfs_sb_t, sb_dblocks),    0 },
  80     { offsetof(xfs_sb_t, sb_rblocks),    0 },
  81     { offsetof(xfs_sb_t, sb_rextents),   0 },
  82     { offsetof(xfs_sb_t, sb_uuid),       1 },
  83     { offsetof(xfs_sb_t, sb_logstart),   0 },
  84     { offsetof(xfs_sb_t, sb_rootino),    0 },
  85     { offsetof(xfs_sb_t, sb_rbmino),     0 },
  86     { offsetof(xfs_sb_t, sb_rsumino),    0 },
  87     { offsetof(xfs_sb_t, sb_rextsize),   0 },
  88     { offsetof(xfs_sb_t, sb_agblocks),   0 },
  89     { offsetof(xfs_sb_t, sb_agcount),    0 },
  90     { offsetof(xfs_sb_t, sb_rbmblocks),  0 },
  91     { offsetof(xfs_sb_t, sb_logblocks),  0 },
  92     { offsetof(xfs_sb_t, sb_versionnum), 0 },
  93     { offsetof(xfs_sb_t, sb_sectsize),   0 },
  94     { offsetof(xfs_sb_t, sb_inodesize),  0 },
  95     { offsetof(xfs_sb_t, sb_inopblock),  0 },
  96     { offsetof(xfs_sb_t, sb_fname[0]),   1 },
  97     { offsetof(xfs_sb_t, sb_blocklog),   0 },
  98     { offsetof(xfs_sb_t, sb_sectlog),    0 },
  99     { offsetof(xfs_sb_t, sb_inodelog),   0 },
 100     { offsetof(xfs_sb_t, sb_inopblog),   0 },
 101     { offsetof(xfs_sb_t, sb_agblklog),   0 },
 102     { offsetof(xfs_sb_t, sb_rextslog),   0 },
 103     { offsetof(xfs_sb_t, sb_inprogress), 0 },
 104     { offsetof(xfs_sb_t, sb_imax_pct),   0 },
 105     { offsetof(xfs_sb_t, sb_icount),     0 },
 106     { offsetof(xfs_sb_t, sb_ifree),      0 },
 107     { offsetof(xfs_sb_t, sb_fdblocks),   0 },
 108     { offsetof(xfs_sb_t, sb_frextents),  0 },
 109     { offsetof(xfs_sb_t, sb_uquotino),   0 },
 110     { offsetof(xfs_sb_t, sb_gquotino),   0 },
 111     { offsetof(xfs_sb_t, sb_qflags),     0 },
 112     { offsetof(xfs_sb_t, sb_flags),      0 },
 113     { offsetof(xfs_sb_t, sb_shared_vn),  0 },
 114     { offsetof(xfs_sb_t, sb_inoalignmt), 0 },
 115     { offsetof(xfs_sb_t, sb_unit),       0 },
 116     { offsetof(xfs_sb_t, sb_width),      0 },
 117     { offsetof(xfs_sb_t, sb_dirblklog),  0 },
 118     { offsetof(xfs_sb_t, sb_logsectlog), 0 },
 119     { offsetof(xfs_sb_t, sb_logsectsize),0 },
 120     { offsetof(xfs_sb_t, sb_logsunit),   0 },
 121     { offsetof(xfs_sb_t, sb_features2),  0 },
 122     { sizeof(xfs_sb_t),                  0 }
 123 };
 124
 125 /*
 126  * Return a pointer to an initialized xfs_mount structure.
 127  */
 128 xfs_mount_t *
 129 xfs_mount_init(void)
 130 {
 131         xfs_mount_t *mp;
 132
 133         mp = kmem_zalloc(sizeof(xfs_mount_t), KM_SLEEP);
 134
 135         if (xfs_icsb_init_counters(mp)) {
 136                 mp->m_flags |= XFS_MOUNT_NO_PERCPU_SB;
 137         }
 138
 139         AIL_LOCKINIT(&mp->m_ail_lock, "xfs_ail");
 140         spinlock_init(&mp->m_sb_lock, "xfs_sb");
 141         mutex_init(&mp->m_ilock);
 142         initnsema(&mp->m_growlock, 1, "xfs_grow");
 143         /*
 144          * Initialize the AIL.
 145          */
 146         xfs_trans_ail_init(mp);
 147
 148         atomic_set(&mp->m_active_trans, 0);
 149
 150         return mp;
 151 }
 152
 153 /*
 154  * Free up the resources associated with a mount structure.  Assume that
 155  * the structure was initially zeroed, so we can tell which fields got
 156  * initialized.
 157  */
 158 void
 159 xfs_mount_free(
 160         xfs_mount_t     *mp,
 161         int             remove_bhv)
 162 {
 163         if (mp->m_ihash)
 164                 xfs_ihash_free(mp);
 165         if (mp->m_chash)
 166                 xfs_chash_free(mp);
 167
 168         if (mp->m_perag) {
 169                 int     agno;
 170
 171                 for (agno = 0; agno < mp->m_maxagi; agno++)
 172                         if (mp->m_perag[agno].pagb_list)
 173                                 kmem_free(mp->m_perag[agno].pagb_list,
 174                                                 sizeof(xfs_perag_busy_t) *
 175                                                         XFS_PAGB_NUM_SLOTS);
 176                 kmem_free(mp->m_perag,
 177                           sizeof(xfs_perag_t) * mp->m_sb.sb_agcount);
 178         }
 179
 180         AIL_LOCK_DESTROY(&mp->m_ail_lock);
 181         spinlock_destroy(&mp->m_sb_lock);
 182         mutex_destroy(&mp->m_ilock);
 183         freesema(&mp->m_growlock);
 184         if (mp->m_quotainfo)
 185                 XFS_QM_DONE(mp);
 186
 187         if (mp->m_fsname != NULL)
 188                 kmem_free(mp->m_fsname, mp->m_fsname_len);
 189         if (mp->m_rtname != NULL)
 190                 kmem_free(mp->m_rtname, strlen(mp->m_rtname) + 1);
 191         if (mp->m_logname != NULL)
 192                 kmem_free(mp->m_logname, strlen(mp->m_logname) + 1);
 193
 194         if (remove_bhv) {
 195                 struct bhv_vfs  *vfsp = XFS_MTOVFS(mp);
 196
 197                 bhv_remove_all_vfsops(vfsp, 0);
 198                 VFS_REMOVEBHV(vfsp, &mp->m_bhv);
 199         }
 200
 201         xfs_icsb_destroy_counters(mp);
 202         kmem_free(mp, sizeof(xfs_mount_t));
 203 }
 204
 205
 206 /*
 207  * Check the validity of the SB found.
 208  */
 209 STATIC int
 210 xfs_mount_validate_sb(
 211         xfs_mount_t     *mp,
 212         xfs_sb_t        *sbp,
 213         int             flags)
 214 {
 215         /*
 216          * If the log device and data device have the
 217          * same device number, the log is internal.
 218          * Consequently, the sb_logstart should be non-zero.  If
 219          * we have a zero sb_logstart in this case, we may be trying to mount
 220          * a volume filesystem in a non-volume manner.
 221          */
 222         if (sbp->sb_magicnum != XFS_SB_MAGIC) {
 223                 xfs_fs_mount_cmn_err(flags, "bad magic number");
 224                 return XFS_ERROR(EWRONGFS);
 225         }
 226
 227         if (!XFS_SB_GOOD_VERSION(sbp)) {
 228                 xfs_fs_mount_cmn_err(flags, "bad version");
 229                 return XFS_ERROR(EWRONGFS);
 230         }
 231
 232         if (unlikely(
 233             sbp->sb_logstart == 0 && mp->m_logdev_targp == mp->m_ddev_targp)) {
 234                 xfs_fs_mount_cmn_err(flags,
 235                         "filesystem is marked as having an external log; "
 236                         "specify logdev on the\nmount command line.");
 237                 return XFS_ERROR(EINVAL);
 238         }
 239
 240         if (unlikely(
 241             sbp->sb_logstart != 0 && mp->m_logdev_targp != mp->m_ddev_targp)) {
 242                 xfs_fs_mount_cmn_err(flags,
 243                         "filesystem is marked as having an internal log; "
 244                         "do not specify logdev on\nthe mount command line.");
 245                 return XFS_ERROR(EINVAL);
 246         }
 247
 248         /*
 249          * More sanity checking. These were stolen directly from
 250          * xfs_repair.
 251          */
 252         if (unlikely(
 253             sbp->sb_agcount <= 0                                        ||
 254             sbp->sb_sectsize < XFS_MIN_SECTORSIZE                       ||
 255             sbp->sb_sectsize > XFS_MAX_SECTORSIZE                       ||
 256             sbp->sb_sectlog < XFS_MIN_SECTORSIZE_LOG                    ||
 257             sbp->sb_sectlog > XFS_MAX_SECTORSIZE_LOG                    ||
 258             sbp->sb_blocksize < XFS_MIN_BLOCKSIZE                       ||
 259             sbp->sb_blocksize > XFS_MAX_BLOCKSIZE                       ||
 260             sbp->sb_blocklog < XFS_MIN_BLOCKSIZE_LOG                    ||
 261             sbp->sb_blocklog > XFS_MAX_BLOCKSIZE_LOG                    ||
 262             sbp->sb_inodesize < XFS_DINODE_MIN_SIZE                     ||
 263             sbp->sb_inodesize > XFS_DINODE_MAX_SIZE                     ||
 264             sbp->sb_inodelog < XFS_DINODE_MIN_LOG                       ||
 265             sbp->sb_inodelog > XFS_DINODE_MAX_LOG                       ||
 266             (sbp->sb_blocklog - sbp->sb_inodelog != sbp->sb_inopblog)   ||
 267             (sbp->sb_rextsize * sbp->sb_blocksize > XFS_MAX_RTEXTSIZE)  ||
 268             (sbp->sb_rextsize * sbp->sb_blocksize < XFS_MIN_RTEXTSIZE)  ||
 269             (sbp->sb_imax_pct > 100 /* zero sb_imax_pct is valid */))) {
 270                 xfs_fs_mount_cmn_err(flags, "SB sanity check 1 failed");
 271                 return XFS_ERROR(EFSCORRUPTED);
 272         }
 273
 274         /*
 275          * Sanity check AG count, size fields against data size field
 276          */
 277         if (unlikely(
 278             sbp->sb_dblocks == 0 ||
 279             sbp->sb_dblocks >
 280              (xfs_drfsbno_t)sbp->sb_agcount * sbp->sb_agblocks ||
 281             sbp->sb_dblocks < (xfs_drfsbno_t)(sbp->sb_agcount - 1) *
 282                               sbp->sb_agblocks + XFS_MIN_AG_BLOCKS)) {
 283                 xfs_fs_mount_cmn_err(flags, "SB sanity check 2 failed");
 284                 return XFS_ERROR(EFSCORRUPTED);
 285         }
 286
 287         ASSERT(PAGE_SHIFT >= sbp->sb_blocklog);
 288         ASSERT(sbp->sb_blocklog >= BBSHIFT);
 289
 290 #if XFS_BIG_BLKNOS     /* Limited by ULONG_MAX of page cache index */
 291         if (unlikely(
 292             (sbp->sb_dblocks >> (PAGE_SHIFT - sbp->sb_blocklog)) > ULONG_MAX ||
 293             (sbp->sb_rblocks >> (PAGE_SHIFT - sbp->sb_blocklog)) > ULONG_MAX)) {
 294 #else                  /* Limited by UINT_MAX of sectors */
 295         if (unlikely(
 296             (sbp->sb_dblocks << (sbp->sb_blocklog - BBSHIFT)) > UINT_MAX ||
 297             (sbp->sb_rblocks << (sbp->sb_blocklog - BBSHIFT)) > UINT_MAX)) {
 298 #endif
 299                 xfs_fs_mount_cmn_err(flags,
 300                         "file system too large to be mounted on this system.");
 301                 return XFS_ERROR(E2BIG);
 302         }
 303
 304         if (unlikely(sbp->sb_inprogress)) {
 305                 xfs_fs_mount_cmn_err(flags, "file system busy");
 306                 return XFS_ERROR(EFSCORRUPTED);
 307         }
 308
 309         /*
 310          * Version 1 directory format has never worked on Linux.
 311          */
 312         if (unlikely(!XFS_SB_VERSION_HASDIRV2(sbp))) {
 313                 xfs_fs_mount_cmn_err(flags,
 314                         "file system using version 1 directory format");
 315                 return XFS_ERROR(ENOSYS);
 316         }
 317
 318         /*
 319          * Until this is fixed only page-sized or smaller data blocks work.
 320          */
 321         if (unlikely(sbp->sb_blocksize > PAGE_SIZE)) {
 322                 xfs_fs_mount_cmn_err(flags,
 323                         "file system with blocksize %d bytes",
 324                         sbp->sb_blocksize);
 325                 xfs_fs_mount_cmn_err(flags,
 326                         "only pagesize (%ld) or less will currently work.",
 327                         PAGE_SIZE);
 328                 return XFS_ERROR(ENOSYS);
 329         }
 330
 331         return 0;
 332 }
 333
 334 xfs_agnumber_t
 335 xfs_initialize_perag(
 336         bhv_vfs_t       *vfs,
 337         xfs_mount_t     *mp,
 338         xfs_agnumber_t  agcount)
 339 {
 340         xfs_agnumber_t  index, max_metadata;
 341         xfs_perag_t     *pag;
 342         xfs_agino_t     agino;
 343         xfs_ino_t       ino;
 344         xfs_sb_t        *sbp = &mp->m_sb;
 345         xfs_ino_t       max_inum = XFS_MAXINUMBER_32;
 346
 347         /* Check to see if the filesystem can overflow 32 bit inodes */
 348         agino = XFS_OFFBNO_TO_AGINO(mp, sbp->sb_agblocks - 1, 0);
 349         ino = XFS_AGINO_TO_INO(mp, agcount - 1, agino);
 350
 351         /* Clear the mount flag if no inode can overflow 32 bits
 352          * on this filesystem, or if specifically requested..
 353          */
 354         if ((vfs->vfs_flag & VFS_32BITINODES) && ino > max_inum) {
 355                 mp->m_flags |= XFS_MOUNT_32BITINODES;
 356         } else {
 357                 mp->m_flags &= ~XFS_MOUNT_32BITINODES;
 358         }
 359
 360         /* If we can overflow then setup the ag headers accordingly */
 361         if (mp->m_flags & XFS_MOUNT_32BITINODES) {
 362                 /* Calculate how much should be reserved for inodes to
 363                  * meet the max inode percentage.
 364                  */
 365                 if (mp->m_maxicount) {
 366                         __uint64_t      icount;
 367
 368                         icount = sbp->sb_dblocks * sbp->sb_imax_pct;
 369                         do_div(icount, 100);
 370                         icount += sbp->sb_agblocks - 1;
 371                         do_div(icount, sbp->sb_agblocks);
 372                         max_metadata = icount;
 373                 } else {
 374                         max_metadata = agcount;
 375                 }
 376                 for (index = 0; index < agcount; index++) {
 377                         ino = XFS_AGINO_TO_INO(mp, index, agino);
 378                         if (ino > max_inum) {
 379                                 index++;
 380                                 break;
 381                         }
 382
 383                         /* This ag is preferred for inodes */
 384                         pag = &mp->m_perag[index];
 385                         pag->pagi_inodeok = 1;
 386                         if (index < max_metadata)
 387                                 pag->pagf_metadata = 1;
 388                 }
 389         } else {
 390                 /* Setup default behavior for smaller filesystems */
 391                 for (index = 0; index < agcount; index++) {
 392                         pag = &mp->m_perag[index];
 393                         pag->pagi_inodeok = 1;
 394                 }
 395         }
 396         return index;
 397 }
 398
 399 /*
 400  * xfs_xlatesb
 401  *
 402  *     data       - on disk version of sb
 403  *     sb         - a superblock
 404  *     dir        - conversion direction: <0 - convert sb to buf
 405  *                                        >0 - convert buf to sb
 406  *     fields     - which fields to copy (bitmask)
 407  */
 408 void
 409 xfs_xlatesb(
 410         void            *data,
 411         xfs_sb_t        *sb,
 412         int             dir,
 413         __int64_t       fields)
 414 {
 415         xfs_caddr_t     buf_ptr;
 416         xfs_caddr_t     mem_ptr;
 417         xfs_sb_field_t  f;
 418         int             first;
 419         int             size;
 420
 421         ASSERT(dir);
 422         ASSERT(fields);
 423
 424         if (!fields)
 425                 return;
 426
 427         buf_ptr = (xfs_caddr_t)data;
 428         mem_ptr = (xfs_caddr_t)sb;
 429
 430         while (fields) {
 431                 f = (xfs_sb_field_t)xfs_lowbit64((__uint64_t)fields);
 432                 first = xfs_sb_info[f].offset;
 433                 size = xfs_sb_info[f + 1].offset - first;
 434
 435                 ASSERT(xfs_sb_info[f].type == 0 || xfs_sb_info[f].type == 1);
 436
 437                 if (size == 1 || xfs_sb_info[f].type == 1) {
 438                         if (dir > 0) {
 439                                 memcpy(mem_ptr + first, buf_ptr + first, size);
 440                         } else {
 441                                 memcpy(buf_ptr + first, mem_ptr + first, size);
 442                         }
 443                 } else {
 444                         switch (size) {
 445                         case 2:
 446                                 INT_XLATE(*(__uint16_t*)(buf_ptr+first),
 447                                           *(__uint16_t*)(mem_ptr+first),
 448                                           dir, ARCH_CONVERT);
 449                                 break;
 450                         case 4:
 451                                 INT_XLATE(*(__uint32_t*)(buf_ptr+first),
 452                                           *(__uint32_t*)(mem_ptr+first),
 453                                           dir, ARCH_CONVERT);
 454                                 break;
 455                         case 8:
 456                                 INT_XLATE(*(__uint64_t*)(buf_ptr+first),
 457                                           *(__uint64_t*)(mem_ptr+first), dir, ARCH_CONVERT);
 458                                 break;
 459                         default:
 460                                 ASSERT(0);
 461                         }
 462                 }
 463
 464                 fields &= ~(1LL << f);
 465         }
 466 }
 467
 468 /*
 469  * xfs_readsb
 470  *
 471  * Does the initial read of the superblock.
 472  */
 473 int
 474 xfs_readsb(xfs_mount_t *mp, int flags)
 475 {
 476         unsigned int    sector_size;
 477         unsigned int    extra_flags;
 478         xfs_buf_t       *bp;
 479         xfs_sb_t        *sbp;
 480         int             error;
 481
 482         ASSERT(mp->m_sb_bp == NULL);
 483         ASSERT(mp->m_ddev_targp != NULL);
 484
 485         /*
 486          * Allocate a (locked) buffer to hold the superblock.
 487          * This will be kept around at all times to optimize
 488          * access to the superblock.
 489          */
 490         sector_size = xfs_getsize_buftarg(mp->m_ddev_targp);
 491         extra_flags = XFS_BUF_LOCK | XFS_BUF_MANAGE | XFS_BUF_MAPPED;
 492
 493         bp = xfs_buf_read_flags(mp->m_ddev_targp, XFS_SB_DADDR,
 494                                 BTOBB(sector_size), extra_flags);
 495         if (!bp || XFS_BUF_ISERROR(bp)) {
 496                 xfs_fs_mount_cmn_err(flags, "SB read failed");
 497                 error = bp ? XFS_BUF_GETERROR(bp) : ENOMEM;
 498                 goto fail;
 499         }
 500         ASSERT(XFS_BUF_ISBUSY(bp));
 501         ASSERT(XFS_BUF_VALUSEMA(bp) <= 0);
 502
 503         /*
 504          * Initialize the mount structure from the superblock.
 505          * But first do some basic consistency checking.
 506          */
 507         sbp = XFS_BUF_TO_SBP(bp);
 508         xfs_xlatesb(XFS_BUF_PTR(bp), &(mp->m_sb), 1, XFS_SB_ALL_BITS);
 509
 510         error = xfs_mount_validate_sb(mp, &(mp->m_sb), flags);
 511         if (error) {
 512                 xfs_fs_mount_cmn_err(flags, "SB validate failed");
 513                 goto fail;
 514         }
 515
 516         /*
 517          * We must be able to do sector-sized and sector-aligned IO.
 518          */
 519         if (sector_size > mp->m_sb.sb_sectsize) {
 520                 xfs_fs_mount_cmn_err(flags,
 521                         "device supports only %u byte sectors (not %u)",
 522                         sector_size, mp->m_sb.sb_sectsize);
 523                 error = ENOSYS;
 524                 goto fail;
 525         }
 526
 527         /*
 528          * If device sector size is smaller than the superblock size,
 529          * re-read the superblock so the buffer is correctly sized.
 530          */
 531         if (sector_size < mp->m_sb.sb_sectsize) {
 532                 XFS_BUF_UNMANAGE(bp);
 533                 xfs_buf_relse(bp);
 534                 sector_size = mp->m_sb.sb_sectsize;
 535                 bp = xfs_buf_read_flags(mp->m_ddev_targp, XFS_SB_DADDR,
 536                                         BTOBB(sector_size), extra_flags);
 537                 if (!bp || XFS_BUF_ISERROR(bp)) {
 538                         xfs_fs_mount_cmn_err(flags, "SB re-read failed");
 539                         error = bp ? XFS_BUF_GETERROR(bp) : ENOMEM;
 540                         goto fail;
 541                 }
 542                 ASSERT(XFS_BUF_ISBUSY(bp));
 543                 ASSERT(XFS_BUF_VALUSEMA(bp) <= 0);
 544         }
 545
 546         /* Initialize per-cpu counters */
 547         xfs_icsb_reinit_counters(mp);
 548
 549         mp->m_sb_bp = bp;
 550         xfs_buf_relse(bp);
 551         ASSERT(XFS_BUF_VALUSEMA(bp) > 0);
 552         return 0;
 553
 554  fail:
 555         if (bp) {
 556                 XFS_BUF_UNMANAGE(bp);
 557                 xfs_buf_relse(bp);
 558         }
 559         return error;
 560 }
 561
 562
 563 /*
 564  * xfs_mount_common
 565  *
 566  * Mount initialization code establishing various mount
 567  * fields from the superblock associated with the given
 568  * mount structure
 569  */
 570 STATIC void
 571 xfs_mount_common(xfs_mount_t *mp, xfs_sb_t *sbp)
 572 {
 573         int     i;
 574
 575         mp->m_agfrotor = mp->m_agirotor = 0;
 576         spinlock_init(&mp->m_agirotor_lock, "m_agirotor_lock");
 577         mp->m_maxagi = mp->m_sb.sb_agcount;
 578         mp->m_blkbit_log = sbp->sb_blocklog + XFS_NBBYLOG;
 579         mp->m_blkbb_log = sbp->sb_blocklog - BBSHIFT;
 580         mp->m_sectbb_log = sbp->sb_sectlog - BBSHIFT;
 581         mp->m_agno_log = xfs_highbit32(sbp->sb_agcount - 1) + 1;
 582         mp->m_agino_log = sbp->sb_inopblog + sbp->sb_agblklog;
 583         mp->m_litino = sbp->sb_inodesize -
 584                 ((uint)sizeof(xfs_dinode_core_t) + (uint)sizeof(xfs_agino_t));
 585         mp->m_blockmask = sbp->sb_blocksize - 1;
 586         mp->m_blockwsize = sbp->sb_blocksize >> XFS_WORDLOG;
 587         mp->m_blockwmask = mp->m_blockwsize - 1;
 588         INIT_LIST_HEAD(&mp->m_del_inodes);
 589
 590         /*
 591          * Setup for attributes, in case they get created.
 592          * This value is for inodes getting attributes for the first time,
 593          * the per-inode value is for old attribute values.
 594          */
 595         ASSERT(sbp->sb_inodesize >= 256 && sbp->sb_inodesize <= 2048);
 596         switch (sbp->sb_inodesize) {
 597         case 256:
 598                 mp->m_attroffset = XFS_LITINO(mp) -
 599                                    XFS_BMDR_SPACE_CALC(MINABTPTRS);
 600                 break;
 601         case 512:
 602         case 1024:
 603         case 2048:
 604                 mp->m_attroffset = XFS_BMDR_SPACE_CALC(6 * MINABTPTRS);
 605                 break;
 606         default:
 607                 ASSERT(0);
 608         }
 609         ASSERT(mp->m_attroffset < XFS_LITINO(mp));
 610
 611         for (i = 0; i < 2; i++) {
 612                 mp->m_alloc_mxr[i] = XFS_BTREE_BLOCK_MAXRECS(sbp->sb_blocksize,
 613                         xfs_alloc, i == 0);
 614                 mp->m_alloc_mnr[i] = XFS_BTREE_BLOCK_MINRECS(sbp->sb_blocksize,
 615                         xfs_alloc, i == 0);
 616         }
 617         for (i = 0; i < 2; i++) {
 618                 mp->m_bmap_dmxr[i] = XFS_BTREE_BLOCK_MAXRECS(sbp->sb_blocksize,
 619                         xfs_bmbt, i == 0);
 620                 mp->m_bmap_dmnr[i] = XFS_BTREE_BLOCK_MINRECS(sbp->sb_blocksize,
 621                         xfs_bmbt, i == 0);
 622         }
 623         for (i = 0; i < 2; i++) {
 624                 mp->m_inobt_mxr[i] = XFS_BTREE_BLOCK_MAXRECS(sbp->sb_blocksize,
 625                         xfs_inobt, i == 0);
 626                 mp->m_inobt_mnr[i] = XFS_BTREE_BLOCK_MINRECS(sbp->sb_blocksize,
 627                         xfs_inobt, i == 0);
 628         }
 629
 630         mp->m_bsize = XFS_FSB_TO_BB(mp, 1);
 631         mp->m_ialloc_inos = (int)MAX((__uint16_t)XFS_INODES_PER_CHUNK,
 632                                         sbp->sb_inopblock);
 633         mp->m_ialloc_blks = mp->m_ialloc_inos >> sbp->sb_inopblog;
 634 }
 635 /*
 636  * xfs_mountfs
 637  *
 638  * This function does the following on an initial mount of a file system:
 639  *      - reads the superblock from disk and init the mount struct
 640  *      - if we're a 32-bit kernel, do a size check on the superblock
 641  *              so we don't mount terabyte filesystems
 642  *      - init mount struct realtime fields
 643  *      - allocate inode hash table for fs
 644  *      - init directory manager
 645  *      - perform recovery and init the log manager
 646  */
 647 int
 648 xfs_mountfs(
 649         bhv_vfs_t       *vfsp,
 650         xfs_mount_t     *mp,
 651         int             mfsi_flags)
 652 {
 653         xfs_buf_t       *bp;
 654         xfs_sb_t        *sbp = &(mp->m_sb);
 655         xfs_inode_t     *rip;
 656         bhv_vnode_t     *rvp = NULL;
 657         int             readio_log, writeio_log;
 658         xfs_daddr_t     d;
 659         __uint64_t      ret64;
 660         __int64_t       update_flags;
 661         uint            quotamount, quotaflags;
 662         int             agno;
 663         int             uuid_mounted = 0;
 664         int             error = 0;
 665
 666         if (mp->m_sb_bp == NULL) {
 667                 if ((error = xfs_readsb(mp, mfsi_flags))) {
 668                         return error;
 669                 }
 670         }
 671         xfs_mount_common(mp, sbp);
 672
 673         /*
 674          * Check if sb_agblocks is aligned at stripe boundary
 675          * If sb_agblocks is NOT aligned turn off m_dalign since
 676          * allocator alignment is within an ag, therefore ag has
 677          * to be aligned at stripe boundary.
 678          */
 679         update_flags = 0LL;
 680         if (mp->m_dalign && !(mfsi_flags & XFS_MFSI_SECOND)) {
 681                 /*
 682                  * If stripe unit and stripe width are not multiples
 683                  * of the fs blocksize turn off alignment.
 684                  */
 685                 if ((BBTOB(mp->m_dalign) & mp->m_blockmask) ||
 686                     (BBTOB(mp->m_swidth) & mp->m_blockmask)) {
 687                         if (mp->m_flags & XFS_MOUNT_RETERR) {
 688                                 cmn_err(CE_WARN,
 689                                         "XFS: alignment check 1 failed");
 690                                 error = XFS_ERROR(EINVAL);
 691                                 goto error1;
 692                         }
 693                         mp->m_dalign = mp->m_swidth = 0;
 694                 } else {
 695                         /*
 696                          * Convert the stripe unit and width to FSBs.
 697                          */
 698                         mp->m_dalign = XFS_BB_TO_FSBT(mp, mp->m_dalign);
 699                         if (mp->m_dalign && (sbp->sb_agblocks % mp->m_dalign)) {
 700                                 if (mp->m_flags & XFS_MOUNT_RETERR) {
 701                                         error = XFS_ERROR(EINVAL);
 702                                         goto error1;
 703                                 }
 704                                 xfs_fs_cmn_err(CE_WARN, mp,
 705 "stripe alignment turned off: sunit(%d)/swidth(%d) incompatible with agsize(%d)",
 706                                         mp->m_dalign, mp->m_swidth,
 707                                         sbp->sb_agblocks);
 708
 709                                 mp->m_dalign = 0;
 710                                 mp->m_swidth = 0;
 711                         } else if (mp->m_dalign) {
 712                                 mp->m_swidth = XFS_BB_TO_FSBT(mp, mp->m_swidth);
 713                         } else {
 714                                 if (mp->m_flags & XFS_MOUNT_RETERR) {
 715                                         xfs_fs_cmn_err(CE_WARN, mp,
 716 "stripe alignment turned off: sunit(%d) less than bsize(%d)",
 717                                                 mp->m_dalign,
 718                                                 mp->m_blockmask +1);
 719                                         error = XFS_ERROR(EINVAL);
 720                                         goto error1;
 721                                 }
 722                                 mp->m_swidth = 0;
 723                         }
 724                 }
 725
 726                 /*
 727                  * Update superblock with new values
 728                  * and log changes
 729                  */
 730                 if (XFS_SB_VERSION_HASDALIGN(sbp)) {
 731                         if (sbp->sb_unit != mp->m_dalign) {
 732                                 sbp->sb_unit = mp->m_dalign;
 733                                 update_flags |= XFS_SB_UNIT;
 734                         }
 735                         if (sbp->sb_width != mp->m_swidth) {
 736                                 sbp->sb_width = mp->m_swidth;
 737                                 update_flags |= XFS_SB_WIDTH;
 738                         }
 739                 }
 740         } else if ((mp->m_flags & XFS_MOUNT_NOALIGN) != XFS_MOUNT_NOALIGN &&
 741                     XFS_SB_VERSION_HASDALIGN(&mp->m_sb)) {
 742                         mp->m_dalign = sbp->sb_unit;
 743                         mp->m_swidth = sbp->sb_width;
 744         }
 745
 746         xfs_alloc_compute_maxlevels(mp);
 747         xfs_bmap_compute_maxlevels(mp, XFS_DATA_FORK);
 748         xfs_bmap_compute_maxlevels(mp, XFS_ATTR_FORK);
 749         xfs_ialloc_compute_maxlevels(mp);
 750
 751         if (sbp->sb_imax_pct) {
 752                 __uint64_t      icount;
 753
 754                 /* Make sure the maximum inode count is a multiple of the
 755                  * units we allocate inodes in.
 756                  */
 757
 758                 icount = sbp->sb_dblocks * sbp->sb_imax_pct;
 759                 do_div(icount, 100);
 760                 do_div(icount, mp->m_ialloc_blks);
 761                 mp->m_maxicount = (icount * mp->m_ialloc_blks)  <<
 762                                    sbp->sb_inopblog;
 763         } else
 764                 mp->m_maxicount = 0;
 765
 766         mp->m_maxioffset = xfs_max_file_offset(sbp->sb_blocklog);
 767
 768         /*
 769          * XFS uses the uuid from the superblock as the unique
 770          * identifier for fsid.  We can not use the uuid from the volume
 771          * since a single partition filesystem is identical to a single
 772          * partition volume/filesystem.
 773          */
 774         if ((mfsi_flags & XFS_MFSI_SECOND) == 0 &&
 775             (mp->m_flags & XFS_MOUNT_NOUUID) == 0) {
 776                 if (xfs_uuid_mount(mp)) {
 777                         error = XFS_ERROR(EINVAL);
 778                         goto error1;
 779                 }
 780                 uuid_mounted=1;
 781                 ret64 = uuid_hash64(&sbp->sb_uuid);
 782                 memcpy(&vfsp->vfs_fsid, &ret64, sizeof(ret64));
 783         }
 784
 785         /*
 786          * Set the default minimum read and write sizes unless
 787          * already specified in a mount option.
 788          * We use smaller I/O sizes when the file system
 789          * is being used for NFS service (wsync mount option).
 790          */
 791         if (!(mp->m_flags & XFS_MOUNT_DFLT_IOSIZE)) {
 792                 if (mp->m_flags & XFS_MOUNT_WSYNC) {
 793                         readio_log = XFS_WSYNC_READIO_LOG;
 794                         writeio_log = XFS_WSYNC_WRITEIO_LOG;
 795                 } else {
 796                         readio_log = XFS_READIO_LOG_LARGE;
 797                         writeio_log = XFS_WRITEIO_LOG_LARGE;
 798                 }
 799         } else {
 800                 readio_log = mp->m_readio_log;
 801                 writeio_log = mp->m_writeio_log;
 802         }
 803
 804         /*
 805          * Set the number of readahead buffers to use based on
 806          * physical memory size.
 807          */
 808         if (xfs_physmem <= 4096)                /* <= 16MB */
 809                 mp->m_nreadaheads = XFS_RW_NREADAHEAD_16MB;
 810         else if (xfs_physmem <= 8192)   /* <= 32MB */
 811                 mp->m_nreadaheads = XFS_RW_NREADAHEAD_32MB;
 812         else
 813                 mp->m_nreadaheads = XFS_RW_NREADAHEAD_K32;
 814         if (sbp->sb_blocklog > readio_log) {
 815                 mp->m_readio_log = sbp->sb_blocklog;
 816         } else {
 817                 mp->m_readio_log = readio_log;
 818         }
 819         mp->m_readio_blocks = 1 << (mp->m_readio_log - sbp->sb_blocklog);
 820         if (sbp->sb_blocklog > writeio_log) {
 821                 mp->m_writeio_log = sbp->sb_blocklog;
 822         } else {
 823                 mp->m_writeio_log = writeio_log;
 824         }
 825         mp->m_writeio_blocks = 1 << (mp->m_writeio_log - sbp->sb_blocklog);
 826
 827         /*
 828          * Set the inode cluster size based on the physical memory
 829          * size.  This may still be overridden by the file system
 830          * block size if it is larger than the chosen cluster size.
 831          */
 832         if (xfs_physmem <= btoc(32 * 1024 * 1024)) { /* <= 32 MB */
 833                 mp->m_inode_cluster_size = XFS_INODE_SMALL_CLUSTER_SIZE;
 834         } else {
 835                 mp->m_inode_cluster_size = XFS_INODE_BIG_CLUSTER_SIZE;
 836         }
 837         /*
 838          * Set whether we're using inode alignment.
 839          */
 840         if (XFS_SB_VERSION_HASALIGN(&mp->m_sb) &&
 841             mp->m_sb.sb_inoalignmt >=
 842             XFS_B_TO_FSBT(mp, mp->m_inode_cluster_size))
 843                 mp->m_inoalign_mask = mp->m_sb.sb_inoalignmt - 1;
 844         else
 845                 mp->m_inoalign_mask = 0;
 846         /*
 847          * If we are using stripe alignment, check whether
 848          * the stripe unit is a multiple of the inode alignment
 849          */
 850         if (mp->m_dalign && mp->m_inoalign_mask &&
 851             !(mp->m_dalign & mp->m_inoalign_mask))
 852                 mp->m_sinoalign = mp->m_dalign;
 853         else
 854                 mp->m_sinoalign = 0;
 855         /*
 856          * Check that the data (and log if separate) are an ok size.
 857          */
 858         d = (xfs_daddr_t)XFS_FSB_TO_BB(mp, mp->m_sb.sb_dblocks);
 859         if (XFS_BB_TO_FSB(mp, d) != mp->m_sb.sb_dblocks) {
 860                 cmn_err(CE_WARN, "XFS: size check 1 failed");
 861                 error = XFS_ERROR(E2BIG);
 862                 goto error1;
 863         }
 864         error = xfs_read_buf(mp, mp->m_ddev_targp,
 865                              d - XFS_FSS_TO_BB(mp, 1),
 866                              XFS_FSS_TO_BB(mp, 1), 0, &bp);
 867         if (!error) {
 868                 xfs_buf_relse(bp);
 869         } else {
 870                 cmn_err(CE_WARN, "XFS: size check 2 failed");
 871                 if (error == ENOSPC) {
 872                         error = XFS_ERROR(E2BIG);
 873                 }
 874                 goto error1;
 875         }
 876
 877         if (((mfsi_flags & XFS_MFSI_CLIENT) == 0) &&
 878             mp->m_logdev_targp != mp->m_ddev_targp) {
 879                 d = (xfs_daddr_t)XFS_FSB_TO_BB(mp, mp->m_sb.sb_logblocks);
 880                 if (XFS_BB_TO_FSB(mp, d) != mp->m_sb.sb_logblocks) {
 881                         cmn_err(CE_WARN, "XFS: size check 3 failed");
 882                         error = XFS_ERROR(E2BIG);
 883                         goto error1;
 884                 }
 885                 error = xfs_read_buf(mp, mp->m_logdev_targp,
 886                                      d - XFS_FSB_TO_BB(mp, 1),
 887                                      XFS_FSB_TO_BB(mp, 1), 0, &bp);
 888                 if (!error) {
 889                         xfs_buf_relse(bp);
 890                 } else {
 891                         cmn_err(CE_WARN, "XFS: size check 3 failed");
 892                         if (error == ENOSPC) {
 893                                 error = XFS_ERROR(E2BIG);
 894                         }
 895                         goto error1;
 896                 }
 897         }
 898
 899         /*
 900          * Initialize realtime fields in the mount structure
 901          */
 902         if ((error = xfs_rtmount_init(mp))) {
 903                 cmn_err(CE_WARN, "XFS: RT mount failed");
 904                 goto error1;
 905         }
 906
 907         /*
 908          * For client case we are done now
 909          */
 910         if (mfsi_flags & XFS_MFSI_CLIENT) {
 911                 return 0;
 912         }
 913
 914         /*
 915          *  Copies the low order bits of the timestamp and the randomly
 916          *  set "sequence" number out of a UUID.
 917          */
 918         uuid_getnodeuniq(&sbp->sb_uuid, mp->m_fixedfsid);
 919
 920         /*
 921          *  The vfs structure needs to have a file system independent
 922          *  way of checking for the invariant file system ID.  Since it
 923          *  can't look at mount structures it has a pointer to the data
 924          *  in the mount structure.
 925          *
 926          *  File systems that don't support user level file handles (i.e.
 927          *  all of them except for XFS) will leave vfs_altfsid as NULL.
 928          */
 929         vfsp->vfs_altfsid = (xfs_fsid_t *)mp->m_fixedfsid;
 930         mp->m_dmevmask = 0;     /* not persistent; set after each mount */
 931
 932         xfs_dir_mount(mp);
 933
 934         /*
 935          * Initialize the attribute manager's entries.
 936          */
 937         mp->m_attr_magicpct = (mp->m_sb.sb_blocksize * 37) / 100;
 938
 939         /*
 940          * Initialize the precomputed transaction reservations values.
 941          */
 942         xfs_trans_init(mp);
 943
 944         /*
 945          * Allocate and initialize the inode hash table for this
 946          * file system.
 947          */
 948         xfs_ihash_init(mp);
 949         xfs_chash_init(mp);
 950
 951         /*
 952          * Allocate and initialize the per-ag data.
 953          */
 954         init_rwsem(&mp->m_peraglock);
 955         mp->m_perag =
 956                 kmem_zalloc(sbp->sb_agcount * sizeof(xfs_perag_t), KM_SLEEP);
 957
 958         mp->m_maxagi = xfs_initialize_perag(vfsp, mp, sbp->sb_agcount);
 959
 960         /*
 961          * log's mount-time initialization. Perform 1st part recovery if needed
 962          */
 963         if (likely(sbp->sb_logblocks > 0)) {    /* check for volume case */
 964                 error = xfs_log_mount(mp, mp->m_logdev_targp,
 965                                       XFS_FSB_TO_DADDR(mp, sbp->sb_logstart),
 966                                       XFS_FSB_TO_BB(mp, sbp->sb_logblocks));
 967                 if (error) {
 968                         cmn_err(CE_WARN, "XFS: log mount failed");
 969                         goto error2;
 970                 }
 971         } else {        /* No log has been defined */
 972                 cmn_err(CE_WARN, "XFS: no log defined");
 973                 XFS_ERROR_REPORT("xfs_mountfs_int(1)", XFS_ERRLEVEL_LOW, mp);
 974                 error = XFS_ERROR(EFSCORRUPTED);
 975                 goto error2;
 976         }
 977
 978         /*
 979          * Get and sanity-check the root inode.
 980          * Save the pointer to it in the mount structure.
 981          */
 982         error = xfs_iget(mp, NULL, sbp->sb_rootino, 0, XFS_ILOCK_EXCL, &rip, 0);
 983         if (error) {
 984                 cmn_err(CE_WARN, "XFS: failed to read root inode");
 985                 goto error3;
 986         }
 987
 988         ASSERT(rip != NULL);
 989         rvp = XFS_ITOV(rip);
 990
 991         if (unlikely((rip->i_d.di_mode & S_IFMT) != S_IFDIR)) {
 992                 cmn_err(CE_WARN, "XFS: corrupted root inode");
 993                 cmn_err(CE_WARN, "Device %s - root %llu is not a directory",
 994                         XFS_BUFTARG_NAME(mp->m_ddev_targp),
 995                         (unsigned long long)rip->i_ino);
 996                 xfs_iunlock(rip, XFS_ILOCK_EXCL);
 997                 XFS_ERROR_REPORT("xfs_mountfs_int(2)", XFS_ERRLEVEL_LOW,
 998                                  mp);
 999                 error = XFS_ERROR(EFSCORRUPTED);
1000                 goto error4;
1001         }
1002         mp->m_rootip = rip;     /* save it */
1003
1004         xfs_iunlock(rip, XFS_ILOCK_EXCL);
1005
1006         /*
1007          * Initialize realtime inode pointers in the mount structure
1008          */
1009         if ((error = xfs_rtmount_inodes(mp))) {
1010                 /*
1011                  * Free up the root inode.
1012                  */
1013                 cmn_err(CE_WARN, "XFS: failed to read RT inodes");
1014                 goto error4;
1015         }
1016
1017         /*
1018          * If fs is not mounted readonly, then update the superblock
1019          * unit and width changes.
1020          */
1021         if (update_flags && !(vfsp->vfs_flag & VFS_RDONLY))
1022                 xfs_mount_log_sbunit(mp, update_flags);
1023
1024         /*
1025          * Initialise the XFS quota management subsystem for this mount
1026          */
1027         if ((error = XFS_QM_INIT(mp, &quotamount, &quotaflags)))
1028                 goto error4;
1029
1030         /*
1031          * Finish recovering the file system.  This part needed to be
1032          * delayed until after the root and real-time bitmap inodes
1033          * were consistently read in.
1034          */
1035         error = xfs_log_mount_finish(mp, mfsi_flags);
1036         if (error) {
1037                 cmn_err(CE_WARN, "XFS: log mount finish failed");
1038                 goto error4;
1039         }
1040
1041         /*
1042          * Complete the quota initialisation, post-log-replay component.
1043          */
1044         if ((error = XFS_QM_MOUNT(mp, quotamount, quotaflags, mfsi_flags)))
1045                 goto error4;
1046
1047         return 0;
1048
1049  error4:
1050         /*
1051          * Free up the root inode.
1052          */
1053         VN_RELE(rvp);
1054  error3:
1055         xfs_log_unmount_dealloc(mp);
1056  error2:
1057         xfs_ihash_free(mp);
1058         xfs_chash_free(mp);
1059         for (agno = 0; agno < sbp->sb_agcount; agno++)
1060                 if (mp->m_perag[agno].pagb_list)
1061                         kmem_free(mp->m_perag[agno].pagb_list,
1062                           sizeof(xfs_perag_busy_t) * XFS_PAGB_NUM_SLOTS);
1063         kmem_free(mp->m_perag, sbp->sb_agcount * sizeof(xfs_perag_t));
1064         mp->m_perag = NULL;
1065         /* FALLTHROUGH */
1066  error1:
1067         if (uuid_mounted)
1068                 xfs_uuid_unmount(mp);
1069         xfs_freesb(mp);
1070         return error;
1071 }
1072
1073 /*
1074  * xfs_unmountfs
1075  *
1076  * This flushes out the inodes,dquots and the superblock, unmounts the
1077  * log and makes sure that incore structures are freed.
1078  */
1079 int
1080 xfs_unmountfs(xfs_mount_t *mp, struct cred *cr)
1081 {
1082         struct bhv_vfs  *vfsp = XFS_MTOVFS(mp);
1083 #if defined(DEBUG) || defined(INDUCE_IO_ERROR)
1084         int64_t         fsid;
1085 #endif
1086
1087         xfs_iflush_all(mp);
1088
1089         XFS_QM_DQPURGEALL(mp, XFS_QMOPT_QUOTALL | XFS_QMOPT_UMOUNTING);
1090
1091         /*
1092          * Flush out the log synchronously so that we know for sure
1093          * that nothing is pinned.  This is important because bflush()
1094          * will skip pinned buffers.
1095          */
1096         xfs_log_force(mp, (xfs_lsn_t)0, XFS_LOG_FORCE | XFS_LOG_SYNC);
1097
1098         xfs_binval(mp->m_ddev_targp);
1099         if (mp->m_rtdev_targp) {
1100                 xfs_binval(mp->m_rtdev_targp);
1101         }
1102
1103         xfs_unmountfs_writesb(mp);
1104
1105         xfs_unmountfs_wait(mp);                 /* wait for async bufs */
1106
1107         xfs_log_unmount(mp);                    /* Done! No more fs ops. */
1108
1109         xfs_freesb(mp);
1110
1111         /*
1112          * All inodes from this mount point should be freed.
1113          */
1114         ASSERT(mp->m_inodes == NULL);
1115
1116         xfs_unmountfs_close(mp, cr);
1117         if ((mp->m_flags & XFS_MOUNT_NOUUID) == 0)
1118                 xfs_uuid_unmount(mp);
1119
1120 #if defined(DEBUG) || defined(INDUCE_IO_ERROR)
1121         /*
1122          * clear all error tags on this filesystem
1123          */
1124         memcpy(&fsid, &vfsp->vfs_fsid, sizeof(int64_t));
1125         xfs_errortag_clearall_umount(fsid, mp->m_fsname, 0);
1126 #endif
1127         XFS_IODONE(vfsp);
1128         xfs_mount_free(mp, 1);
1129         return 0;
1130 }
1131
1132 void
1133 xfs_unmountfs_close(xfs_mount_t *mp, struct cred *cr)
1134 {
1135         if (mp->m_logdev_targp != mp->m_ddev_targp)
1136                 xfs_free_buftarg(mp->m_logdev_targp, 1);
1137         if (mp->m_rtdev_targp)
1138                 xfs_free_buftarg(mp->m_rtdev_targp, 1);
1139         xfs_free_buftarg(mp->m_ddev_targp, 0);
1140 }
1141
1142 STATIC void
1143 xfs_unmountfs_wait(xfs_mount_t *mp)
1144 {
1145         if (mp->m_logdev_targp != mp->m_ddev_targp)
1146                 xfs_wait_buftarg(mp->m_logdev_targp);
1147         if (mp->m_rtdev_targp)
1148                 xfs_wait_buftarg(mp->m_rtdev_targp);
1149         xfs_wait_buftarg(mp->m_ddev_targp);
1150 }
1151
1152 int
1153 xfs_unmountfs_writesb(xfs_mount_t *mp)
1154 {
1155         xfs_buf_t       *sbp;
1156         xfs_sb_t        *sb;
1157         int             error = 0;
1158
1159         /*
1160          * skip superblock write if fs is read-only, or
1161          * if we are doing a forced umount.
1162          */
1163         sbp = xfs_getsb(mp, 0);
1164         if (!(XFS_MTOVFS(mp)->vfs_flag & VFS_RDONLY ||
1165                 XFS_FORCED_SHUTDOWN(mp))) {
1166
1167                 xfs_icsb_sync_counters(mp);
1168
1169                 /*
1170                  * mark shared-readonly if desired
1171                  */
1172                 sb = XFS_BUF_TO_SBP(sbp);
1173                 if (mp->m_mk_sharedro) {
1174                         if (!(sb->sb_flags & XFS_SBF_READONLY))
1175                                 sb->sb_flags |= XFS_SBF_READONLY;
1176                         if (!XFS_SB_VERSION_HASSHARED(sb))
1177                                 XFS_SB_VERSION_ADDSHARED(sb);
1178                         xfs_fs_cmn_err(CE_NOTE, mp,
1179                                 "Unmounting, marking shared read-only");
1180                 }
1181                 XFS_BUF_UNDONE(sbp);
1182                 XFS_BUF_UNREAD(sbp);
1183                 XFS_BUF_UNDELAYWRITE(sbp);
1184                 XFS_BUF_WRITE(sbp);
1185                 XFS_BUF_UNASYNC(sbp);
1186                 ASSERT(XFS_BUF_TARGET(sbp) == mp->m_ddev_targp);
1187                 xfsbdstrat(mp, sbp);
1188                 /* Nevermind errors we might get here. */
1189                 error = xfs_iowait(sbp);
1190                 if (error)
1191                         xfs_ioerror_alert("xfs_unmountfs_writesb",
1192                                           mp, sbp, XFS_BUF_ADDR(sbp));
1193                 if (error && mp->m_mk_sharedro)
1194                         xfs_fs_cmn_err(CE_ALERT, mp, "Superblock write error detected while unmounting.  Filesystem may not be marked shared readonly");
1195         }
1196         xfs_buf_relse(sbp);
1197         return error;
1198 }
1199
1200 /*
1201  * xfs_mod_sb() can be used to copy arbitrary changes to the
1202  * in-core superblock into the superblock buffer to be logged.
1203  * It does not provide the higher level of locking that is
1204  * needed to protect the in-core superblock from concurrent
1205  * access.
1206  */
1207 void
1208 xfs_mod_sb(xfs_trans_t *tp, __int64_t fields)
1209 {
1210         xfs_buf_t       *bp;
1211         int             first;
1212         int             last;
1213         xfs_mount_t     *mp;
1214         xfs_sb_t        *sbp;
1215         xfs_sb_field_t  f;
1216
1217         ASSERT(fields);
1218         if (!fields)
1219                 return;
1220         mp = tp->t_mountp;
1221         bp = xfs_trans_getsb(tp, mp, 0);
1222         sbp = XFS_BUF_TO_SBP(bp);
1223         first = sizeof(xfs_sb_t);
1224         last = 0;
1225
1226         /* translate/copy */
1227
1228         xfs_xlatesb(XFS_BUF_PTR(bp), &(mp->m_sb), -1, fields);
1229
1230         /* find modified range */
1231
1232         f = (xfs_sb_field_t)xfs_lowbit64((__uint64_t)fields);
1233         ASSERT((1LL << f) & XFS_SB_MOD_BITS);
1234         first = xfs_sb_info[f].offset;
1235
1236         f = (xfs_sb_field_t)xfs_highbit64((__uint64_t)fields);
1237         ASSERT((1LL << f) & XFS_SB_MOD_BITS);
1238         last = xfs_sb_info[f + 1].offset - 1;
1239
1240         xfs_trans_log_buf(tp, bp, first, last);
1241 }
1242
1243
1244 /*
1245  * xfs_mod_incore_sb_unlocked() is a utility routine common used to apply
1246  * a delta to a specified field in the in-core superblock.  Simply
1247  * switch on the field indicated and apply the delta to that field.
1248  * Fields are not allowed to dip below zero, so if the delta would
1249  * do this do not apply it and return EINVAL.
1250  *
1251  * The SB_LOCK must be held when this routine is called.
1252  */
1253 int
1254 xfs_mod_incore_sb_unlocked(
1255         xfs_mount_t     *mp,
1256         xfs_sb_field_t  field,
1257         int64_t         delta,
1258         int             rsvd)
1259 {
1260         int             scounter;       /* short counter for 32 bit fields */
1261         long long       lcounter;       /* long counter for 64 bit fields */
1262         long long       res_used, rem;
1263
1264         /*
1265          * With the in-core superblock spin lock held, switch
1266          * on the indicated field.  Apply the delta to the
1267          * proper field.  If the fields value would dip below
1268          * 0, then do not apply the delta and return EINVAL.
1269          */
1270         switch (field) {
1271         case XFS_SBS_ICOUNT:
1272                 lcounter = (long long)mp->m_sb.sb_icount;
1273                 lcounter += delta;
1274                 if (lcounter < 0) {
1275                         ASSERT(0);
1276                         return XFS_ERROR(EINVAL);
1277                 }
1278                 mp->m_sb.sb_icount = lcounter;
1279                 return 0;
1280         case XFS_SBS_IFREE:
1281                 lcounter = (long long)mp->m_sb.sb_ifree;
1282                 lcounter += delta;
1283                 if (lcounter < 0) {
1284                         ASSERT(0);
1285                         return XFS_ERROR(EINVAL);
1286                 }
1287                 mp->m_sb.sb_ifree = lcounter;
1288                 return 0;
1289         case XFS_SBS_FDBLOCKS:
1290                 lcounter = (long long)
1291                         mp->m_sb.sb_fdblocks - XFS_ALLOC_SET_ASIDE(mp);
1292                 res_used = (long long)(mp->m_resblks - mp->m_resblks_avail);
1293
1294                 if (delta > 0) {                /* Putting blocks back */
1295                         if (res_used > delta) {
1296                                 mp->m_resblks_avail += delta;
1297                         } else {
1298                                 rem = delta - res_used;
1299                                 mp->m_resblks_avail = mp->m_resblks;
1300                                 lcounter += rem;
1301                         }
1302                 } else {                                /* Taking blocks away */
1303
1304                         lcounter += delta;
1305
1306                 /*
1307                  * If were out of blocks, use any available reserved blocks if
1308                  * were allowed to.
1309                  */
1310
1311                         if (lcounter < 0) {
1312                                 if (rsvd) {
1313                                         lcounter = (long long)mp->m_resblks_avail + delta;
1314                                         if (lcounter < 0) {
1315                                                 return XFS_ERROR(ENOSPC);
1316                                         }
1317                                         mp->m_resblks_avail = lcounter;
1318                                         return 0;
1319                                 } else {        /* not reserved */
1320                                         return XFS_ERROR(ENOSPC);
1321                                 }
1322                         }
1323                 }
1324
1325                 mp->m_sb.sb_fdblocks = lcounter + XFS_ALLOC_SET_ASIDE(mp);
1326                 return 0;
1327         case XFS_SBS_FREXTENTS:
1328                 lcounter = (long long)mp->m_sb.sb_frextents;
1329                 lcounter += delta;
1330                 if (lcounter < 0) {
1331                         return XFS_ERROR(ENOSPC);
1332                 }
1333                 mp->m_sb.sb_frextents = lcounter;
1334                 return 0;
1335         case XFS_SBS_DBLOCKS:
1336                 lcounter = (long long)mp->m_sb.sb_dblocks;
1337                 lcounter += delta;
1338                 if (lcounter < 0) {
1339                         ASSERT(0);
1340                         return XFS_ERROR(EINVAL);
1341                 }
1342                 mp->m_sb.sb_dblocks = lcounter;
1343                 return 0;
1344         case XFS_SBS_AGCOUNT:
1345                 scounter = mp->m_sb.sb_agcount;
1346                 scounter += delta;
1347                 if (scounter < 0) {
1348                         ASSERT(0);
1349                         return XFS_ERROR(EINVAL);
1350                 }
1351                 mp->m_sb.sb_agcount = scounter;
1352                 return 0;
1353         case XFS_SBS_IMAX_PCT:
1354                 scounter = mp->m_sb.sb_imax_pct;
1355                 scounter += delta;
1356                 if (scounter < 0) {
1357                         ASSERT(0);
1358                         return XFS_ERROR(EINVAL);
1359                 }
1360                 mp->m_sb.sb_imax_pct = scounter;
1361                 return 0;
1362         case XFS_SBS_REXTSIZE:
1363                 scounter = mp->m_sb.sb_rextsize;
1364                 scounter += delta;
1365                 if (scounter < 0) {
1366                         ASSERT(0);
1367                         return XFS_ERROR(EINVAL);
1368                 }
1369                 mp->m_sb.sb_rextsize = scounter;
1370                 return 0;
1371         case XFS_SBS_RBMBLOCKS:
1372                 scounter = mp->m_sb.sb_rbmblocks;
1373                 scounter += delta;
1374                 if (scounter < 0) {
1375                         ASSERT(0);
1376                         return XFS_ERROR(EINVAL);
1377                 }
1378                 mp->m_sb.sb_rbmblocks = scounter;
1379                 return 0;
1380         case XFS_SBS_RBLOCKS:
1381                 lcounter = (long long)mp->m_sb.sb_rblocks;
1382                 lcounter += delta;
1383                 if (lcounter < 0) {
1384                         ASSERT(0);
1385                         return XFS_ERROR(EINVAL);
1386                 }
1387                 mp->m_sb.sb_rblocks = lcounter;
1388                 return 0;
1389         case XFS_SBS_REXTENTS:
1390                 lcounter = (long long)mp->m_sb.sb_rextents;
1391                 lcounter += delta;
1392                 if (lcounter < 0) {
1393                         ASSERT(0);
1394                         return XFS_ERROR(EINVAL);
1395                 }
1396                 mp->m_sb.sb_rextents = lcounter;
1397                 return 0;
1398         case XFS_SBS_REXTSLOG:
1399                 scounter = mp->m_sb.sb_rextslog;
1400                 scounter += delta;
1401                 if (scounter < 0) {
1402                         ASSERT(0);
1403                         return XFS_ERROR(EINVAL);
1404                 }
1405                 mp->m_sb.sb_rextslog = scounter;
1406                 return 0;
1407         default:
1408                 ASSERT(0);
1409                 return XFS_ERROR(EINVAL);
1410         }
1411 }
1412
1413 /*
1414  * xfs_mod_incore_sb() is used to change a field in the in-core
1415  * superblock structure by the specified delta.  This modification
1416  * is protected by the SB_LOCK.  Just use the xfs_mod_incore_sb_unlocked()
1417  * routine to do the work.
1418  */
1419 int
1420 xfs_mod_incore_sb(
1421         xfs_mount_t     *mp,
1422         xfs_sb_field_t  field,
1423         int64_t         delta,
1424         int             rsvd)
1425 {
1426         unsigned long   s;
1427         int     status;
1428
1429         /* check for per-cpu counters */
1430         switch (field) {
1431 #ifdef HAVE_PERCPU_SB
1432         case XFS_SBS_ICOUNT:
1433         case XFS_SBS_IFREE:
1434         case XFS_SBS_FDBLOCKS:
1435                 if (!(mp->m_flags & XFS_MOUNT_NO_PERCPU_SB)) {
1436                         status = xfs_icsb_modify_counters(mp, field,
1437                                                         delta, rsvd);
1438                         break;
1439                 }
1440                 /* FALLTHROUGH */
1441 #endif
1442         default:
1443                 s = XFS_SB_LOCK(mp);
1444                 status = xfs_mod_incore_sb_unlocked(mp, field, delta, rsvd);
1445                 XFS_SB_UNLOCK(mp, s);
1446                 break;
1447         }
1448
1449         return status;
1450 }
1451
1452 /*
1453  * xfs_mod_incore_sb_batch() is used to change more than one field
1454  * in the in-core superblock structure at a time.  This modification
1455  * is protected by a lock internal to this module.  The fields and
1456  * changes to those fields are specified in the array of xfs_mod_sb
1457  * structures passed in.
1458  *
1459  * Either all of the specified deltas will be applied or none of
1460  * them will.  If any modified field dips below 0, then all modifications
1461  * will be backed out and EINVAL will be returned.
1462  */
1463 int
1464 xfs_mod_incore_sb_batch(xfs_mount_t *mp, xfs_mod_sb_t *msb, uint nmsb, int rsvd)
1465 {
1466         unsigned long   s;
1467         int             status=0;
1468         xfs_mod_sb_t    *msbp;
1469
1470         /*
1471          * Loop through the array of mod structures and apply each
1472          * individually.  If any fail, then back out all those
1473          * which have already been applied.  Do all of this within
1474          * the scope of the SB_LOCK so that all of the changes will
1475          * be atomic.
1476          */
1477         s = XFS_SB_LOCK(mp);
1478         msbp = &msb[0];
1479         for (msbp = &msbp[0]; msbp < (msb + nmsb); msbp++) {
1480                 /*
1481                  * Apply the delta at index n.  If it fails, break
1482                  * from the loop so we'll fall into the undo loop
1483                  * below.
1484                  */
1485                 switch (msbp->msb_field) {
1486 #ifdef HAVE_PERCPU_SB
1487                 case XFS_SBS_ICOUNT:
1488                 case XFS_SBS_IFREE:
1489                 case XFS_SBS_FDBLOCKS:
1490                         if (!(mp->m_flags & XFS_MOUNT_NO_PERCPU_SB)) {
1491                                 XFS_SB_UNLOCK(mp, s);
1492                                 status = xfs_icsb_modify_counters(mp,
1493                                                         msbp->msb_field,
1494                                                         msbp->msb_delta, rsvd);
1495                                 s = XFS_SB_LOCK(mp);
1496                                 break;
1497                         }
1498                         /* FALLTHROUGH */
1499 #endif
1500                 default:
1501                         status = xfs_mod_incore_sb_unlocked(mp,
1502                                                 msbp->msb_field,
1503                                                 msbp->msb_delta, rsvd);
1504                         break;
1505                 }
1506
1507                 if (status != 0) {
1508                         break;
1509                 }
1510         }
1511
1512         /*
1513          * If we didn't complete the loop above, then back out
1514          * any changes made to the superblock.  If you add code
1515          * between the loop above and here, make sure that you
1516          * preserve the value of status. Loop back until
1517          * we step below the beginning of the array.  Make sure
1518          * we don't touch anything back there.
1519          */
1520         if (status != 0) {
1521                 msbp--;
1522                 while (msbp >= msb) {
1523                         switch (msbp->msb_field) {
1524 #ifdef HAVE_PERCPU_SB
1525                         case XFS_SBS_ICOUNT:
1526                         case XFS_SBS_IFREE:
1527                         case XFS_SBS_FDBLOCKS:
1528                                 if (!(mp->m_flags & XFS_MOUNT_NO_PERCPU_SB)) {
1529                                         XFS_SB_UNLOCK(mp, s);
1530                                         status = xfs_icsb_modify_counters(mp,
1531                                                         msbp->msb_field,
1532                                                         -(msbp->msb_delta),
1533                                                         rsvd);
1534                                         s = XFS_SB_LOCK(mp);
1535                                         break;
1536                                 }
1537                                 /* FALLTHROUGH */
1538 #endif
1539                         default:
1540                                 status = xfs_mod_incore_sb_unlocked(mp,
1541                                                         msbp->msb_field,
1542                                                         -(msbp->msb_delta),
1543                                                         rsvd);
1544                                 break;
1545                         }
1546                         ASSERT(status == 0);
1547                         msbp--;
1548                 }
1549         }
1550         XFS_SB_UNLOCK(mp, s);
1551         return status;
1552 }
1553
1554 /*
1555  * xfs_getsb() is called to obtain the buffer for the superblock.
1556  * The buffer is returned locked and read in from disk.
1557  * The buffer should be released with a call to xfs_brelse().
1558  *
1559  * If the flags parameter is BUF_TRYLOCK, then we'll only return
1560  * the superblock buffer if it can be locked without sleeping.
1561  * If it can't then we'll return NULL.
1562  */
1563 xfs_buf_t *
1564 xfs_getsb(
1565         xfs_mount_t     *mp,
1566         int             flags)
1567 {
1568         xfs_buf_t       *bp;
1569
1570         ASSERT(mp->m_sb_bp != NULL);
1571         bp = mp->m_sb_bp;
1572         if (flags & XFS_BUF_TRYLOCK) {
1573                 if (!XFS_BUF_CPSEMA(bp)) {
1574                         return NULL;
1575                 }
1576         } else {
1577                 XFS_BUF_PSEMA(bp, PRIBIO);
1578         }
1579         XFS_BUF_HOLD(bp);
1580         ASSERT(XFS_BUF_ISDONE(bp));
1581         return bp;
1582 }
1583
1584 /*
1585  * Used to free the superblock along various error paths.
1586  */
1587 void
1588 xfs_freesb(
1589         xfs_mount_t     *mp)
1590 {
1591         xfs_buf_t       *bp;
1592
1593         /*
1594          * Use xfs_getsb() so that the buffer will be locked
1595          * when we call xfs_buf_relse().
1596          */
1597         bp = xfs_getsb(mp, 0);
1598         XFS_BUF_UNMANAGE(bp);
1599         xfs_buf_relse(bp);
1600         mp->m_sb_bp = NULL;
1601 }
1602
1603 /*
1604  * See if the UUID is unique among mounted XFS filesystems.
1605  * Mount fails if UUID is nil or a FS with the same UUID is already mounted.
1606  */
1607 STATIC int
1608 xfs_uuid_mount(
1609         xfs_mount_t     *mp)
1610 {
1611         if (uuid_is_nil(&mp->m_sb.sb_uuid)) {
1612                 cmn_err(CE_WARN,
1613                         "XFS: Filesystem %s has nil UUID - can't mount",
1614                         mp->m_fsname);
1615                 return -1;
1616         }
1617         if (!uuid_table_insert(&mp->m_sb.sb_uuid)) {
1618                 cmn_err(CE_WARN,
1619                         "XFS: Filesystem %s has duplicate UUID - can't mount",
1620                         mp->m_fsname);
1621                 return -1;
1622         }
1623         return 0;
1624 }
1625
1626 /*
1627  * Remove filesystem from the UUID table.
1628  */
1629 STATIC void
1630 xfs_uuid_unmount(
1631         xfs_mount_t     *mp)
1632 {
1633         uuid_table_remove(&mp->m_sb.sb_uuid);
1634 }
1635
1636 /*
1637  * Used to log changes to the superblock unit and width fields which could
1638  * be altered by the mount options. Only the first superblock is updated.
1639  */
1640 STATIC void
1641 xfs_mount_log_sbunit(
1642         xfs_mount_t     *mp,
1643         __int64_t       fields)
1644 {
1645         xfs_trans_t     *tp;
1646
1647         ASSERT(fields & (XFS_SB_UNIT|XFS_SB_WIDTH|XFS_SB_UUID));
1648
1649         tp = xfs_trans_alloc(mp, XFS_TRANS_SB_UNIT);
1650         if (xfs_trans_reserve(tp, 0, mp->m_sb.sb_sectsize + 128, 0, 0,
1651                                 XFS_DEFAULT_LOG_COUNT)) {
1652                 xfs_trans_cancel(tp, 0);
1653                 return;
1654         }
1655         xfs_mod_sb(tp, fields);
1656         xfs_trans_commit(tp, 0, NULL);
1657 }
1658
1659
1660 #ifdef HAVE_PERCPU_SB
1661 /*
1662  * Per-cpu incore superblock counters
1663  *
1664  * Simple concept, difficult implementation
1665  *
1666  * Basically, replace the incore superblock counters with a distributed per cpu
1667  * counter for contended fields (e.g.  free block count).
1668  *
1669  * Difficulties arise in that the incore sb is used for ENOSPC checking, and
1670  * hence needs to be accurately read when we are running low on space. Hence
1671  * there is a method to enable and disable the per-cpu counters based on how
1672  * much "stuff" is available in them.
1673  *
1674  * Basically, a counter is enabled if there is enough free resource to justify
1675  * running a per-cpu fast-path. If the per-cpu counter runs out (i.e. a local
1676  * ENOSPC), then we disable the counters to synchronise all callers and
1677  * re-distribute the available resources.
1678  *
1679  * If, once we redistributed the available resources, we still get a failure,
1680  * we disable the per-cpu counter and go through the slow path.
1681  *
1682  * The slow path is the current xfs_mod_incore_sb() function.  This means that
1683  * when we disable a per-cpu counter, we need to drain it's resources back to
1684  * the global superblock. We do this after disabling the counter to prevent
1685  * more threads from queueing up on the counter.
1686  *
1687  * Essentially, this means that we still need a lock in the fast path to enable
1688  * synchronisation between the global counters and the per-cpu counters. This
1689  * is not a problem because the lock will be local to a CPU almost all the time
1690  * and have little contention except when we get to ENOSPC conditions.
1691  *
1692  * Basically, this lock becomes a barrier that enables us to lock out the fast
1693  * path while we do things like enabling and disabling counters and
1694  * synchronising the counters.
1695  *
1696  * Locking rules:
1697  *
1698  *      1. XFS_SB_LOCK() before picking up per-cpu locks
1699  *      2. per-cpu locks always picked up via for_each_online_cpu() order
1700  *      3. accurate counter sync requires XFS_SB_LOCK + per cpu locks
1701  *      4. modifying per-cpu counters requires holding per-cpu lock
1702  *      5. modifying global counters requires holding XFS_SB_LOCK
1703  *      6. enabling or disabling a counter requires holding the XFS_SB_LOCK
1704  *         and _none_ of the per-cpu locks.
1705  *
1706  * Disabled counters are only ever re-enabled by a balance operation
1707  * that results in more free resources per CPU than a given threshold.
1708  * To ensure counters don't remain disabled, they are rebalanced when
1709  * the global resource goes above a higher threshold (i.e. some hysteresis
1710  * is present to prevent thrashing).
1711  */
1712
1713 #ifdef CONFIG_HOTPLUG_CPU
1714 /*
1715  * hot-plug CPU notifier support.
1716  *
1717  * We need a notifier per filesystem as we need to be able to identify
1718  * the filesystem to balance the counters out. This is achieved by
1719  * having a notifier block embedded in the xfs_mount_t and doing pointer
1720  * magic to get the mount pointer from the notifier block address.
1721  */
1722 STATIC int
1723 xfs_icsb_cpu_notify(
1724         struct notifier_block *nfb,
1725         unsigned long action,
1726         void *hcpu)
1727 {
1728         xfs_icsb_cnts_t *cntp;
1729         xfs_mount_t     *mp;
1730         int             s;
1731
1732         mp = (xfs_mount_t *)container_of(nfb, xfs_mount_t, m_icsb_notifier);
1733         cntp = (xfs_icsb_cnts_t *)
1734                         per_cpu_ptr(mp->m_sb_cnts, (unsigned long)hcpu);
1735         switch (action) {
1736         case CPU_UP_PREPARE:
1737                 /* Easy Case - initialize the area and locks, and
1738                  * then rebalance when online does everything else for us. */
1739                 memset(cntp, 0, sizeof(xfs_icsb_cnts_t));
1740                 break;
1741         case CPU_ONLINE:
1742                 xfs_icsb_lock(mp);
1743                 xfs_icsb_balance_counter(mp, XFS_SBS_ICOUNT, 0, 0);
1744                 xfs_icsb_balance_counter(mp, XFS_SBS_IFREE, 0, 0);
1745                 xfs_icsb_balance_counter(mp, XFS_SBS_FDBLOCKS, 0, 0);
1746                 xfs_icsb_unlock(mp);
1747                 break;
1748         case CPU_DEAD:
1749                 /* Disable all the counters, then fold the dead cpu's
1750                  * count into the total on the global superblock and
1751                  * re-enable the counters. */
1752                 xfs_icsb_lock(mp);
1753                 s = XFS_SB_LOCK(mp);
1754                 xfs_icsb_disable_counter(mp, XFS_SBS_ICOUNT);
1755                 xfs_icsb_disable_counter(mp, XFS_SBS_IFREE);
1756                 xfs_icsb_disable_counter(mp, XFS_SBS_FDBLOCKS);
1757
1758                 mp->m_sb.sb_icount += cntp->icsb_icount;
1759                 mp->m_sb.sb_ifree += cntp->icsb_ifree;
1760                 mp->m_sb.sb_fdblocks += cntp->icsb_fdblocks;
1761
1762                 memset(cntp, 0, sizeof(xfs_icsb_cnts_t));
1763
1764                 xfs_icsb_balance_counter(mp, XFS_SBS_ICOUNT,
1765                                          XFS_ICSB_SB_LOCKED, 0);
1766                 xfs_icsb_balance_counter(mp, XFS_SBS_IFREE,
1767                                          XFS_ICSB_SB_LOCKED, 0);
1768                 xfs_icsb_balance_counter(mp, XFS_SBS_FDBLOCKS,
1769                                          XFS_ICSB_SB_LOCKED, 0);
1770                 XFS_SB_UNLOCK(mp, s);
1771                 xfs_icsb_unlock(mp);
1772                 break;
1773         }
1774
1775         return NOTIFY_OK;
1776 }
1777 #endif /* CONFIG_HOTPLUG_CPU */
1778
1779 int
1780 xfs_icsb_init_counters(
1781         xfs_mount_t     *mp)
1782 {
1783         xfs_icsb_cnts_t *cntp;
1784         int             i;
1785
1786         mp->m_sb_cnts = alloc_percpu(xfs_icsb_cnts_t);
1787         if (mp->m_sb_cnts == NULL)
1788                 return -ENOMEM;
1789
1790 #ifdef CONFIG_HOTPLUG_CPU
1791         mp->m_icsb_notifier.notifier_call = xfs_icsb_cpu_notify;
1792         mp->m_icsb_notifier.priority = 0;
1793         register_hotcpu_notifier(&mp->m_icsb_notifier);
1794 #endif /* CONFIG_HOTPLUG_CPU */
1795
1796         for_each_online_cpu(i) {
1797                 cntp = (xfs_icsb_cnts_t *)per_cpu_ptr(mp->m_sb_cnts, i);
1798                 memset(cntp, 0, sizeof(xfs_icsb_cnts_t));
1799         }
1800
1801         mutex_init(&mp->m_icsb_mutex);
1802
1803         /*
1804          * start with all counters disabled so that the
1805          * initial balance kicks us off correctly
1806          */
1807         mp->m_icsb_counters = -1;
1808         return 0;
1809 }
1810
1811 void
1812 xfs_icsb_reinit_counters(
1813         xfs_mount_t     *mp)
1814 {
1815         xfs_icsb_lock(mp);
1816         /*
1817          * start with all counters disabled so that the
1818          * initial balance kicks us off correctly
1819          */
1820         mp->m_icsb_counters = -1;
1821         xfs_icsb_balance_counter(mp, XFS_SBS_ICOUNT, 0, 0);
1822         xfs_icsb_balance_counter(mp, XFS_SBS_IFREE, 0, 0);
1823         xfs_icsb_balance_counter(mp, XFS_SBS_FDBLOCKS, 0, 0);
1824         xfs_icsb_unlock(mp);
1825 }
1826
1827 STATIC void
1828 xfs_icsb_destroy_counters(
1829         xfs_mount_t     *mp)
1830 {
1831         if (mp->m_sb_cnts) {
1832                 unregister_hotcpu_notifier(&mp->m_icsb_notifier);
1833                 free_percpu(mp->m_sb_cnts);
1834         }
1835         mutex_destroy(&mp->m_icsb_mutex);
1836 }
1837
1838 STATIC_INLINE void
1839 xfs_icsb_lock_cntr(
1840         xfs_icsb_cnts_t *icsbp)
1841 {
1842         while (test_and_set_bit(XFS_ICSB_FLAG_LOCK, &icsbp->icsb_flags)) {
1843                 ndelay(1000);
1844         }
1845 }
1846
1847 STATIC_INLINE void
1848 xfs_icsb_unlock_cntr(
1849         xfs_icsb_cnts_t *icsbp)
1850 {
1851         clear_bit(XFS_ICSB_FLAG_LOCK, &icsbp->icsb_flags);
1852 }
1853
1854
1855 STATIC_INLINE void
1856 xfs_icsb_lock_all_counters(
1857         xfs_mount_t     *mp)
1858 {
1859         xfs_icsb_cnts_t *cntp;
1860         int             i;
1861
1862         for_each_online_cpu(i) {
1863                 cntp = (xfs_icsb_cnts_t *)per_cpu_ptr(mp->m_sb_cnts, i);
1864                 xfs_icsb_lock_cntr(cntp);
1865         }
1866 }
1867
1868 STATIC_INLINE void
1869 xfs_icsb_unlock_all_counters(
1870         xfs_mount_t     *mp)
1871 {
1872         xfs_icsb_cnts_t *cntp;
1873         int             i;
1874
1875         for_each_online_cpu(i) {
1876                 cntp = (xfs_icsb_cnts_t *)per_cpu_ptr(mp->m_sb_cnts, i);
1877                 xfs_icsb_unlock_cntr(cntp);
1878         }
1879 }
1880
1881 STATIC void
1882 xfs_icsb_count(
1883         xfs_mount_t     *mp,
1884         xfs_icsb_cnts_t *cnt,
1885         int             flags)
1886 {
1887         xfs_icsb_cnts_t *cntp;
1888         int             i;
1889
1890         memset(cnt, 0, sizeof(xfs_icsb_cnts_t));
1891
1892         if (!(flags & XFS_ICSB_LAZY_COUNT))
1893                 xfs_icsb_lock_all_counters(mp);
1894
1895         for_each_online_cpu(i) {
1896                 cntp = (xfs_icsb_cnts_t *)per_cpu_ptr(mp->m_sb_cnts, i);
1897                 cnt->icsb_icount += cntp->icsb_icount;
1898                 cnt->icsb_ifree += cntp->icsb_ifree;
1899                 cnt->icsb_fdblocks += cntp->icsb_fdblocks;
1900         }
1901
1902         if (!(flags & XFS_ICSB_LAZY_COUNT))
1903                 xfs_icsb_unlock_all_counters(mp);
1904 }
1905
1906 STATIC int
1907 xfs_icsb_counter_disabled(
1908         xfs_mount_t     *mp,
1909         xfs_sb_field_t  field)
1910 {
1911         ASSERT((field >= XFS_SBS_ICOUNT) && (field <= XFS_SBS_FDBLOCKS));
1912         return test_bit(field, &mp->m_icsb_counters);
1913 }
1914
1915 STATIC int
1916 xfs_icsb_disable_counter(
1917         xfs_mount_t     *mp,
1918         xfs_sb_field_t  field)
1919 {
1920         xfs_icsb_cnts_t cnt;
1921
1922         ASSERT((field >= XFS_SBS_ICOUNT) && (field <= XFS_SBS_FDBLOCKS));
1923
1924         /*
1925          * If we are already disabled, then there is nothing to do
1926          * here. We check before locking all the counters to avoid
1927          * the expensive lock operation when being called in the
1928          * slow path and the counter is already disabled. This is
1929          * safe because the only time we set or clear this state is under
1930          * the m_icsb_mutex.
1931          */
1932         if (xfs_icsb_counter_disabled(mp, field))
1933                 return 0;
1934
1935         xfs_icsb_lock_all_counters(mp);
1936         if (!test_and_set_bit(field, &mp->m_icsb_counters)) {
1937                 /* drain back to superblock */
1938
1939                 xfs_icsb_count(mp, &cnt, XFS_ICSB_SB_LOCKED|XFS_ICSB_LAZY_COUNT);
1940                 switch(field) {
1941                 case XFS_SBS_ICOUNT:
1942                         mp->m_sb.sb_icount = cnt.icsb_icount;
1943                         break;
1944                 case XFS_SBS_IFREE:
1945                         mp->m_sb.sb_ifree = cnt.icsb_ifree;
1946                         break;
1947                 case XFS_SBS_FDBLOCKS:
1948                         mp->m_sb.sb_fdblocks = cnt.icsb_fdblocks;
1949                         break;
1950                 default:
1951                         BUG();
1952                 }
1953         }
1954
1955         xfs_icsb_unlock_all_counters(mp);
1956
1957         return 0;
1958 }
1959
1960 STATIC void
1961 xfs_icsb_enable_counter(
1962         xfs_mount_t     *mp,
1963         xfs_sb_field_t  field,
1964         uint64_t        count,
1965         uint64_t        resid)
1966 {
1967         xfs_icsb_cnts_t *cntp;
1968         int             i;
1969
1970         ASSERT((field >= XFS_SBS_ICOUNT) && (field <= XFS_SBS_FDBLOCKS));
1971
1972         xfs_icsb_lock_all_counters(mp);
1973         for_each_online_cpu(i) {
1974                 cntp = per_cpu_ptr(mp->m_sb_cnts, i);
1975                 switch (field) {
1976                 case XFS_SBS_ICOUNT:
1977                         cntp->icsb_icount = count + resid;
1978                         break;
1979                 case XFS_SBS_IFREE:
1980                         cntp->icsb_ifree = count + resid;
1981                         break;
1982                 case XFS_SBS_FDBLOCKS:
1983                         cntp->icsb_fdblocks = count + resid;
1984                         break;
1985                 default:
1986                         BUG();
1987                         break;
1988                 }
1989                 resid = 0;
1990         }
1991         clear_bit(field, &mp->m_icsb_counters);
1992         xfs_icsb_unlock_all_counters(mp);
1993 }
1994
1995 void
1996 xfs_icsb_sync_counters_flags(
1997         xfs_mount_t     *mp,
1998         int             flags)
1999 {
2000         xfs_icsb_cnts_t cnt;
2001         int             s;
2002
2003         /* Pass 1: lock all counters */
2004         if ((flags & XFS_ICSB_SB_LOCKED) == 0)
2005                 s = XFS_SB_LOCK(mp);
2006
2007         xfs_icsb_count(mp, &cnt, flags);
2008
2009         /* Step 3: update mp->m_sb fields */
2010         if (!xfs_icsb_counter_disabled(mp, XFS_SBS_ICOUNT))
2011                 mp->m_sb.sb_icount = cnt.icsb_icount;
2012         if (!xfs_icsb_counter_disabled(mp, XFS_SBS_IFREE))
2013                 mp->m_sb.sb_ifree = cnt.icsb_ifree;
2014         if (!xfs_icsb_counter_disabled(mp, XFS_SBS_FDBLOCKS))
2015                 mp->m_sb.sb_fdblocks = cnt.icsb_fdblocks;
2016
2017         if ((flags & XFS_ICSB_SB_LOCKED) == 0)
2018                 XFS_SB_UNLOCK(mp, s);
2019 }
2020
2021 /*
2022  * Accurate update of per-cpu counters to incore superblock
2023  */
2024 STATIC void
2025 xfs_icsb_sync_counters(
2026         xfs_mount_t     *mp)
2027 {
2028         xfs_icsb_sync_counters_flags(mp, 0);
2029 }
2030
2031 /*
2032  * Balance and enable/disable counters as necessary.
2033  *
2034  * Thresholds for re-enabling counters are somewhat magic.  inode counts are
2035  * chosen to be the same number as single on disk allocation chunk per CPU, and
2036  * free blocks is something far enough zero that we aren't going thrash when we
2037  * get near ENOSPC. We also need to supply a minimum we require per cpu to
2038  * prevent looping endlessly when xfs_alloc_space asks for more than will
2039  * be distributed to a single CPU but each CPU has enough blocks to be
2040  * reenabled.
2041  *
2042  * Note that we can be called when counters are already disabled.
2043  * xfs_icsb_disable_counter() optimises the counter locking in this case to
2044  * prevent locking every per-cpu counter needlessly.
2045  */
2046
2047 #define XFS_ICSB_INO_CNTR_REENABLE      (uint64_t)64
2048 #define XFS_ICSB_FDBLK_CNTR_REENABLE(mp) \
2049                 (uint64_t)(512 + XFS_ALLOC_SET_ASIDE(mp))
2050 STATIC void
2051 xfs_icsb_balance_counter(
2052         xfs_mount_t     *mp,
2053         xfs_sb_field_t  field,
2054         int             flags,
2055         int             min_per_cpu)
2056 {
2057         uint64_t        count, resid;
2058         int             weight = num_online_cpus();
2059         int             s;
2060         uint64_t        min = (uint64_t)min_per_cpu;
2061
2062         if (!(flags & XFS_ICSB_SB_LOCKED))
2063                 s = XFS_SB_LOCK(mp);
2064
2065         /* disable counter and sync counter */
2066         xfs_icsb_disable_counter(mp, field);
2067
2068         /* update counters  - first CPU gets residual*/
2069         switch (field) {
2070         case XFS_SBS_ICOUNT:
2071                 count = mp->m_sb.sb_icount;
2072                 resid = do_div(count, weight);
2073                 if (count < max(min, XFS_ICSB_INO_CNTR_REENABLE))
2074                         goto out;
2075                 break;
2076         case XFS_SBS_IFREE:
2077                 count = mp->m_sb.sb_ifree;
2078                 resid = do_div(count, weight);
2079                 if (count < max(min, XFS_ICSB_INO_CNTR_REENABLE))
2080                         goto out;
2081                 break;
2082         case XFS_SBS_FDBLOCKS:
2083                 count = mp->m_sb.sb_fdblocks;
2084                 resid = do_div(count, weight);
2085                 if (count < max(min, XFS_ICSB_FDBLK_CNTR_REENABLE(mp)))
2086                         goto out;
2087                 break;
2088         default:
2089                 BUG();
2090                 count = resid = 0;      /* quiet, gcc */
2091                 break;
2092         }
2093
2094         xfs_icsb_enable_counter(mp, field, count, resid);
2095 out:
2096         if (!(flags & XFS_ICSB_SB_LOCKED))
2097                 XFS_SB_UNLOCK(mp, s);
2098 }
2099
2100 int
2101 xfs_icsb_modify_counters(
2102         xfs_mount_t     *mp,
2103         xfs_sb_field_t  field,
2104         int64_t         delta,
2105         int             rsvd)
2106 {
2107         xfs_icsb_cnts_t *icsbp;
2108         long long       lcounter;       /* long counter for 64 bit fields */
2109         int             cpu, ret = 0, s;
2110
2111         might_sleep();
2112 again:
2113         cpu = get_cpu();
2114         icsbp = (xfs_icsb_cnts_t *)per_cpu_ptr(mp->m_sb_cnts, cpu);
2115
2116         /*
2117          * if the counter is disabled, go to slow path
2118          */
2119         if (unlikely(xfs_icsb_counter_disabled(mp, field)))
2120                 goto slow_path;
2121         xfs_icsb_lock_cntr(icsbp);
2122         if (unlikely(xfs_icsb_counter_disabled(mp, field))) {
2123                 xfs_icsb_unlock_cntr(icsbp);
2124                 goto slow_path;
2125         }
2126
2127         switch (field) {
2128         case XFS_SBS_ICOUNT:
2129                 lcounter = icsbp->icsb_icount;
2130                 lcounter += delta;
2131                 if (unlikely(lcounter < 0))
2132                         goto balance_counter;
2133                 icsbp->icsb_icount = lcounter;
2134                 break;
2135
2136         case XFS_SBS_IFREE:
2137                 lcounter = icsbp->icsb_ifree;
2138                 lcounter += delta;
2139                 if (unlikely(lcounter < 0))
2140                         goto balance_counter;
2141                 icsbp->icsb_ifree = lcounter;
2142                 break;
2143
2144         case XFS_SBS_FDBLOCKS:
2145                 BUG_ON((mp->m_resblks - mp->m_resblks_avail) != 0);
2146
2147                 lcounter = icsbp->icsb_fdblocks - XFS_ALLOC_SET_ASIDE(mp);
2148                 lcounter += delta;
2149                 if (unlikely(lcounter < 0))
2150                         goto balance_counter;
2151                 icsbp->icsb_fdblocks = lcounter + XFS_ALLOC_SET_ASIDE(mp);
2152                 break;
2153         default:
2154                 BUG();
2155                 break;
2156         }
2157         xfs_icsb_unlock_cntr(icsbp);
2158         put_cpu();
2159         return 0;
2160
2161 slow_path:
2162         put_cpu();
2163
2164         /*
2165          * serialise with a mutex so we don't burn lots of cpu on
2166          * the superblock lock. We still need to hold the superblock
2167          * lock, however, when we modify the global structures.
2168          */
2169         xfs_icsb_lock(mp);
2170
2171         /*
2172          * Now running atomically.
2173          *
2174          * If the counter is enabled, someone has beaten us to rebalancing.
2175          * Drop the lock and try again in the fast path....
2176          */
2177         if (!(xfs_icsb_counter_disabled(mp, field))) {
2178                 xfs_icsb_unlock(mp);
2179                 goto again;
2180         }
2181
2182         /*
2183          * The counter is currently disabled. Because we are
2184          * running atomically here, we know a rebalance cannot
2185          * be in progress. Hence we can go straight to operating
2186          * on the global superblock. We do not call xfs_mod_incore_sb()
2187          * here even though we need to get the SB_LOCK. Doing so
2188          * will cause us to re-enter this function and deadlock.
2189          * Hence we get the SB_LOCK ourselves and then call
2190          * xfs_mod_incore_sb_unlocked() as the unlocked path operates
2191          * directly on the global counters.
2192          */
2193         s = XFS_SB_LOCK(mp);
2194         ret = xfs_mod_incore_sb_unlocked(mp, field, delta, rsvd);
2195         XFS_SB_UNLOCK(mp, s);
2196
2197         /*
2198          * Now that we've modified the global superblock, we
2199          * may be able to re-enable the distributed counters
2200          * (e.g. lots of space just got freed). After that
2201          * we are done.
2202          */
2203         if (ret != ENOSPC)
2204                 xfs_icsb_balance_counter(mp, field, 0, 0);
2205         xfs_icsb_unlock(mp);
2206         return ret;
2207
2208 balance_counter:
2209         xfs_icsb_unlock_cntr(icsbp);
2210         put_cpu();
2211
2212         /*
2213          * We may have multiple threads here if multiple per-cpu
2214          * counters run dry at the same time. This will mean we can
2215          * do more balances than strictly necessary but it is not
2216          * the common slowpath case.
2217          */
2218         xfs_icsb_lock(mp);
2219
2220         /*
2221          * running atomically.
2222          *
2223          * This will leave the counter in the correct state for future
2224          * accesses. After the rebalance, we simply try again and our retry
2225          * will either succeed through the fast path or slow path without
2226          * another balance operation being required.
2227          */
2228         xfs_icsb_balance_counter(mp, field, 0, delta);
2229         xfs_icsb_unlock(mp);
2230         goto again;
2231 }
2232
2233 #endif