fs/xfs/xfs_mount.c

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This source file includes following definitions.
xfs_uuid_table_free
xfs_uuid_mount
xfs_uuid_unmount
__xfs_free_perag
xfs_free_perag
xfs_sb_validate_fsb_count
xfs_initialize_perag
xfs_readsb
xfs_update_alignment
xfs_set_rw_sizes
xfs_set_low_space_thresholds
xfs_check_sizes
xfs_mount_reset_sbqflags
xfs_default_resblks
xfs_check_summary_counts
xfs_mountfs
xfs_unmountfs
xfs_fs_writable
xfs_log_sbcount
xfs_mod_icount
xfs_mod_ifree
xfs_mod_fdblocks
xfs_mod_frextents
xfs_getsb
xfs_freesb
xfs_dev_is_read_only
xfs_force_summary_recalc
xfs_mod_delalloc
   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Copyright (c) 2000-2005 Silicon Graphics, Inc.
   4  * All Rights Reserved.
   5  */
   6 #include "xfs.h"
   7 #include "xfs_fs.h"
   8 #include "xfs_shared.h"
   9 #include "xfs_format.h"
  10 #include "xfs_log_format.h"
  11 #include "xfs_trans_resv.h"
  12 #include "xfs_bit.h"
  13 #include "xfs_sb.h"
  14 #include "xfs_mount.h"
  15 #include "xfs_inode.h"
  16 #include "xfs_dir2.h"
  17 #include "xfs_ialloc.h"
  18 #include "xfs_alloc.h"
  19 #include "xfs_rtalloc.h"
  20 #include "xfs_bmap.h"
  21 #include "xfs_trans.h"
  22 #include "xfs_trans_priv.h"
  23 #include "xfs_log.h"
  24 #include "xfs_error.h"
  25 #include "xfs_quota.h"
  26 #include "xfs_fsops.h"
  27 #include "xfs_icache.h"
  28 #include "xfs_sysfs.h"
  29 #include "xfs_rmap_btree.h"
  30 #include "xfs_refcount_btree.h"
  31 #include "xfs_reflink.h"
  32 #include "xfs_extent_busy.h"
  33 #include "xfs_health.h"
  34 
  35 
  36 static DEFINE_MUTEX(xfs_uuid_table_mutex);
  37 static int xfs_uuid_table_size;
  38 static uuid_t *xfs_uuid_table;
  39 
  40 void
  41 xfs_uuid_table_free(void)
  42 {
  43         if (xfs_uuid_table_size == 0)
  44                 return;
  45         kmem_free(xfs_uuid_table);
  46         xfs_uuid_table = NULL;
  47         xfs_uuid_table_size = 0;
  48 }
  49 
  50 /*
  51  * See if the UUID is unique among mounted XFS filesystems.
  52  * Mount fails if UUID is nil or a FS with the same UUID is already mounted.
  53  */
  54 STATIC int
  55 xfs_uuid_mount(
  56         struct xfs_mount        *mp)
  57 {
  58         uuid_t                  *uuid = &mp->m_sb.sb_uuid;
  59         int                     hole, i;
  60 
  61         /* Publish UUID in struct super_block */
  62         uuid_copy(&mp->m_super->s_uuid, uuid);
  63 
  64         if (mp->m_flags & XFS_MOUNT_NOUUID)
  65                 return 0;
  66 
  67         if (uuid_is_null(uuid)) {
  68                 xfs_warn(mp, "Filesystem has null UUID - can't mount");
  69                 return -EINVAL;
  70         }
  71 
  72         mutex_lock(&xfs_uuid_table_mutex);
  73         for (i = 0, hole = -1; i < xfs_uuid_table_size; i++) {
  74                 if (uuid_is_null(&xfs_uuid_table[i])) {
  75                         hole = i;
  76                         continue;
  77                 }
  78                 if (uuid_equal(uuid, &xfs_uuid_table[i]))
  79                         goto out_duplicate;
  80         }
  81 
  82         if (hole < 0) {
  83                 xfs_uuid_table = kmem_realloc(xfs_uuid_table,
  84                         (xfs_uuid_table_size + 1) * sizeof(*xfs_uuid_table),
  85                         0);
  86                 hole = xfs_uuid_table_size++;
  87         }
  88         xfs_uuid_table[hole] = *uuid;
  89         mutex_unlock(&xfs_uuid_table_mutex);
  90 
  91         return 0;
  92 
  93  out_duplicate:
  94         mutex_unlock(&xfs_uuid_table_mutex);
  95         xfs_warn(mp, "Filesystem has duplicate UUID %pU - can't mount", uuid);
  96         return -EINVAL;
  97 }
  98 
  99 STATIC void
 100 xfs_uuid_unmount(
 101         struct xfs_mount        *mp)
 102 {
 103         uuid_t                  *uuid = &mp->m_sb.sb_uuid;
 104         int                     i;
 105 
 106         if (mp->m_flags & XFS_MOUNT_NOUUID)
 107                 return;
 108 
 109         mutex_lock(&xfs_uuid_table_mutex);
 110         for (i = 0; i < xfs_uuid_table_size; i++) {
 111                 if (uuid_is_null(&xfs_uuid_table[i]))
 112                         continue;
 113                 if (!uuid_equal(uuid, &xfs_uuid_table[i]))
 114                         continue;
 115                 memset(&xfs_uuid_table[i], 0, sizeof(uuid_t));
 116                 break;
 117         }
 118         ASSERT(i < xfs_uuid_table_size);
 119         mutex_unlock(&xfs_uuid_table_mutex);
 120 }
 121 
 122 
 123 STATIC void
 124 __xfs_free_perag(
 125         struct rcu_head *head)
 126 {
 127         struct xfs_perag *pag = container_of(head, struct xfs_perag, rcu_head);
 128 
 129         ASSERT(atomic_read(&pag->pag_ref) == 0);
 130         kmem_free(pag);
 131 }
 132 
 133 /*
 134  * Free up the per-ag resources associated with the mount structure.
 135  */
 136 STATIC void
 137 xfs_free_perag(
 138         xfs_mount_t     *mp)
 139 {
 140         xfs_agnumber_t  agno;
 141         struct xfs_perag *pag;
 142 
 143         for (agno = 0; agno < mp->m_sb.sb_agcount; agno++) {
 144                 spin_lock(&mp->m_perag_lock);
 145                 pag = radix_tree_delete(&mp->m_perag_tree, agno);
 146                 spin_unlock(&mp->m_perag_lock);
 147                 ASSERT(pag);
 148                 ASSERT(atomic_read(&pag->pag_ref) == 0);
 149                 xfs_iunlink_destroy(pag);
 150                 xfs_buf_hash_destroy(pag);
 151                 mutex_destroy(&pag->pag_ici_reclaim_lock);
 152                 call_rcu(&pag->rcu_head, __xfs_free_perag);
 153         }
 154 }
 155 
 156 /*
 157  * Check size of device based on the (data/realtime) block count.
 158  * Note: this check is used by the growfs code as well as mount.
 159  */
 160 int
 161 xfs_sb_validate_fsb_count(
 162         xfs_sb_t        *sbp,
 163         uint64_t        nblocks)
 164 {
 165         ASSERT(PAGE_SHIFT >= sbp->sb_blocklog);
 166         ASSERT(sbp->sb_blocklog >= BBSHIFT);
 167 
 168         /* Limited by ULONG_MAX of page cache index */
 169         if (nblocks >> (PAGE_SHIFT - sbp->sb_blocklog) > ULONG_MAX)
 170                 return -EFBIG;
 171         return 0;
 172 }
 173 
 174 int
 175 xfs_initialize_perag(
 176         xfs_mount_t     *mp,
 177         xfs_agnumber_t  agcount,
 178         xfs_agnumber_t  *maxagi)
 179 {
 180         xfs_agnumber_t  index;
 181         xfs_agnumber_t  first_initialised = NULLAGNUMBER;
 182         xfs_perag_t     *pag;
 183         int             error = -ENOMEM;
 184 
 185         /*
 186          * Walk the current per-ag tree so we don't try to initialise AGs
 187          * that already exist (growfs case). Allocate and insert all the
 188          * AGs we don't find ready for initialisation.
 189          */
 190         for (index = 0; index < agcount; index++) {
 191                 pag = xfs_perag_get(mp, index);
 192                 if (pag) {
 193                         xfs_perag_put(pag);
 194                         continue;
 195                 }
 196 
 197                 pag = kmem_zalloc(sizeof(*pag), KM_MAYFAIL);
 198                 if (!pag)
 199                         goto out_unwind_new_pags;
 200                 pag->pag_agno = index;
 201                 pag->pag_mount = mp;
 202                 spin_lock_init(&pag->pag_ici_lock);
 203                 mutex_init(&pag->pag_ici_reclaim_lock);
 204                 INIT_RADIX_TREE(&pag->pag_ici_root, GFP_ATOMIC);
 205                 if (xfs_buf_hash_init(pag))
 206                         goto out_free_pag;
 207                 init_waitqueue_head(&pag->pagb_wait);
 208                 spin_lock_init(&pag->pagb_lock);
 209                 pag->pagb_count = 0;
 210                 pag->pagb_tree = RB_ROOT;
 211 
 212                 if (radix_tree_preload(GFP_NOFS))
 213                         goto out_hash_destroy;
 214 
 215                 spin_lock(&mp->m_perag_lock);
 216                 if (radix_tree_insert(&mp->m_perag_tree, index, pag)) {
 217                         WARN_ON_ONCE(1);
 218                         spin_unlock(&mp->m_perag_lock);
 219                         radix_tree_preload_end();
 220                         error = -EEXIST;
 221                         goto out_hash_destroy;
 222                 }
 223                 spin_unlock(&mp->m_perag_lock);
 224                 radix_tree_preload_end();
 225                 /* first new pag is fully initialized */
 226                 if (first_initialised == NULLAGNUMBER)
 227                         first_initialised = index;
 228                 error = xfs_iunlink_init(pag);
 229                 if (error)
 230                         goto out_hash_destroy;
 231                 spin_lock_init(&pag->pag_state_lock);
 232         }
 233 
 234         index = xfs_set_inode_alloc(mp, agcount);
 235 
 236         if (maxagi)
 237                 *maxagi = index;
 238 
 239         mp->m_ag_prealloc_blocks = xfs_prealloc_blocks(mp);
 240         return 0;
 241 
 242 out_hash_destroy:
 243         xfs_buf_hash_destroy(pag);
 244 out_free_pag:
 245         mutex_destroy(&pag->pag_ici_reclaim_lock);
 246         kmem_free(pag);
 247 out_unwind_new_pags:
 248         /* unwind any prior newly initialized pags */
 249         for (index = first_initialised; index < agcount; index++) {
 250                 pag = radix_tree_delete(&mp->m_perag_tree, index);
 251                 if (!pag)
 252                         break;
 253                 xfs_buf_hash_destroy(pag);
 254                 xfs_iunlink_destroy(pag);
 255                 mutex_destroy(&pag->pag_ici_reclaim_lock);
 256                 kmem_free(pag);
 257         }
 258         return error;
 259 }
 260 
 261 /*
 262  * xfs_readsb
 263  *
 264  * Does the initial read of the superblock.
 265  */
 266 int
 267 xfs_readsb(
 268         struct xfs_mount *mp,
 269         int             flags)
 270 {
 271         unsigned int    sector_size;
 272         struct xfs_buf  *bp;
 273         struct xfs_sb   *sbp = &mp->m_sb;
 274         int             error;
 275         int             loud = !(flags & XFS_MFSI_QUIET);
 276         const struct xfs_buf_ops *buf_ops;
 277 
 278         ASSERT(mp->m_sb_bp == NULL);
 279         ASSERT(mp->m_ddev_targp != NULL);
 280 
 281         /*
 282          * For the initial read, we must guess at the sector
 283          * size based on the block device.  It's enough to
 284          * get the sb_sectsize out of the superblock and
 285          * then reread with the proper length.
 286          * We don't verify it yet, because it may not be complete.
 287          */
 288         sector_size = xfs_getsize_buftarg(mp->m_ddev_targp);
 289         buf_ops = NULL;
 290 
 291         /*
 292          * Allocate a (locked) buffer to hold the superblock. This will be kept
 293          * around at all times to optimize access to the superblock. Therefore,
 294          * set XBF_NO_IOACCT to make sure it doesn't hold the buftarg count
 295          * elevated.
 296          */
 297 reread:
 298         error = xfs_buf_read_uncached(mp->m_ddev_targp, XFS_SB_DADDR,
 299                                       BTOBB(sector_size), XBF_NO_IOACCT, &bp,
 300                                       buf_ops);
 301         if (error) {
 302                 if (loud)
 303                         xfs_warn(mp, "SB validate failed with error %d.", error);
 304                 /* bad CRC means corrupted metadata */
 305                 if (error == -EFSBADCRC)
 306                         error = -EFSCORRUPTED;
 307                 return error;
 308         }
 309 
 310         /*
 311          * Initialize the mount structure from the superblock.
 312          */
 313         xfs_sb_from_disk(sbp, XFS_BUF_TO_SBP(bp));
 314 
 315         /*
 316          * If we haven't validated the superblock, do so now before we try
 317          * to check the sector size and reread the superblock appropriately.
 318          */
 319         if (sbp->sb_magicnum != XFS_SB_MAGIC) {
 320                 if (loud)
 321                         xfs_warn(mp, "Invalid superblock magic number");
 322                 error = -EINVAL;
 323                 goto release_buf;
 324         }
 325 
 326         /*
 327          * We must be able to do sector-sized and sector-aligned IO.
 328          */
 329         if (sector_size > sbp->sb_sectsize) {
 330                 if (loud)
 331                         xfs_warn(mp, "device supports %u byte sectors (not %u)",
 332                                 sector_size, sbp->sb_sectsize);
 333                 error = -ENOSYS;
 334                 goto release_buf;
 335         }
 336 
 337         if (buf_ops == NULL) {
 338                 /*
 339                  * Re-read the superblock so the buffer is correctly sized,
 340                  * and properly verified.
 341                  */
 342                 xfs_buf_relse(bp);
 343                 sector_size = sbp->sb_sectsize;
 344                 buf_ops = loud ? &xfs_sb_buf_ops : &xfs_sb_quiet_buf_ops;
 345                 goto reread;
 346         }
 347 
 348         xfs_reinit_percpu_counters(mp);
 349 
 350         /* no need to be quiet anymore, so reset the buf ops */
 351         bp->b_ops = &xfs_sb_buf_ops;
 352 
 353         mp->m_sb_bp = bp;
 354         xfs_buf_unlock(bp);
 355         return 0;
 356 
 357 release_buf:
 358         xfs_buf_relse(bp);
 359         return error;
 360 }
 361 
 362 /*
 363  * Update alignment values based on mount options and sb values
 364  */
 365 STATIC int
 366 xfs_update_alignment(xfs_mount_t *mp)
 367 {
 368         xfs_sb_t        *sbp = &(mp->m_sb);
 369 
 370         if (mp->m_dalign) {
 371                 /*
 372                  * If stripe unit and stripe width are not multiples
 373                  * of the fs blocksize turn off alignment.
 374                  */
 375                 if ((BBTOB(mp->m_dalign) & mp->m_blockmask) ||
 376                     (BBTOB(mp->m_swidth) & mp->m_blockmask)) {
 377                         xfs_warn(mp,
 378                 "alignment check failed: sunit/swidth vs. blocksize(%d)",
 379                                 sbp->sb_blocksize);
 380                         return -EINVAL;
 381                 } else {
 382                         /*
 383                          * Convert the stripe unit and width to FSBs.
 384                          */
 385                         mp->m_dalign = XFS_BB_TO_FSBT(mp, mp->m_dalign);
 386                         if (mp->m_dalign && (sbp->sb_agblocks % mp->m_dalign)) {
 387                                 xfs_warn(mp,
 388                         "alignment check failed: sunit/swidth vs. agsize(%d)",
 389                                          sbp->sb_agblocks);
 390                                 return -EINVAL;
 391                         } else if (mp->m_dalign) {
 392                                 mp->m_swidth = XFS_BB_TO_FSBT(mp, mp->m_swidth);
 393                         } else {
 394                                 xfs_warn(mp,
 395                         "alignment check failed: sunit(%d) less than bsize(%d)",
 396                                          mp->m_dalign, sbp->sb_blocksize);
 397                                 return -EINVAL;
 398                         }
 399                 }
 400 
 401                 /*
 402                  * Update superblock with new values
 403                  * and log changes
 404                  */
 405                 if (xfs_sb_version_hasdalign(sbp)) {
 406                         if (sbp->sb_unit != mp->m_dalign) {
 407                                 sbp->sb_unit = mp->m_dalign;
 408                                 mp->m_update_sb = true;
 409                         }
 410                         if (sbp->sb_width != mp->m_swidth) {
 411                                 sbp->sb_width = mp->m_swidth;
 412                                 mp->m_update_sb = true;
 413                         }
 414                 } else {
 415                         xfs_warn(mp,
 416         "cannot change alignment: superblock does not support data alignment");
 417                         return -EINVAL;
 418                 }
 419         } else if ((mp->m_flags & XFS_MOUNT_NOALIGN) != XFS_MOUNT_NOALIGN &&
 420                     xfs_sb_version_hasdalign(&mp->m_sb)) {
 421                         mp->m_dalign = sbp->sb_unit;
 422                         mp->m_swidth = sbp->sb_width;
 423         }
 424 
 425         return 0;
 426 }
 427 
 428 /*
 429  * Set the default minimum read and write sizes unless
 430  * already specified in a mount option.
 431  * We use smaller I/O sizes when the file system
 432  * is being used for NFS service (wsync mount option).
 433  */
 434 STATIC void
 435 xfs_set_rw_sizes(xfs_mount_t *mp)
 436 {
 437         xfs_sb_t        *sbp = &(mp->m_sb);
 438         int             readio_log, writeio_log;
 439 
 440         if (!(mp->m_flags & XFS_MOUNT_DFLT_IOSIZE)) {
 441                 if (mp->m_flags & XFS_MOUNT_WSYNC) {
 442                         readio_log = XFS_WSYNC_READIO_LOG;
 443                         writeio_log = XFS_WSYNC_WRITEIO_LOG;
 444                 } else {
 445                         readio_log = XFS_READIO_LOG_LARGE;
 446                         writeio_log = XFS_WRITEIO_LOG_LARGE;
 447                 }
 448         } else {
 449                 readio_log = mp->m_readio_log;
 450                 writeio_log = mp->m_writeio_log;
 451         }
 452 
 453         if (sbp->sb_blocklog > readio_log) {
 454                 mp->m_readio_log = sbp->sb_blocklog;
 455         } else {
 456                 mp->m_readio_log = readio_log;
 457         }
 458         mp->m_readio_blocks = 1 << (mp->m_readio_log - sbp->sb_blocklog);
 459         if (sbp->sb_blocklog > writeio_log) {
 460                 mp->m_writeio_log = sbp->sb_blocklog;
 461         } else {
 462                 mp->m_writeio_log = writeio_log;
 463         }
 464         mp->m_writeio_blocks = 1 << (mp->m_writeio_log - sbp->sb_blocklog);
 465 }
 466 
 467 /*
 468  * precalculate the low space thresholds for dynamic speculative preallocation.
 469  */
 470 void
 471 xfs_set_low_space_thresholds(
 472         struct xfs_mount        *mp)
 473 {
 474         int i;
 475 
 476         for (i = 0; i < XFS_LOWSP_MAX; i++) {
 477                 uint64_t space = mp->m_sb.sb_dblocks;
 478 
 479                 do_div(space, 100);
 480                 mp->m_low_space[i] = space * (i + 1);
 481         }
 482 }
 483 
 484 /*
 485  * Check that the data (and log if separate) is an ok size.
 486  */
 487 STATIC int
 488 xfs_check_sizes(
 489         struct xfs_mount *mp)
 490 {
 491         struct xfs_buf  *bp;
 492         xfs_daddr_t     d;
 493         int             error;
 494 
 495         d = (xfs_daddr_t)XFS_FSB_TO_BB(mp, mp->m_sb.sb_dblocks);
 496         if (XFS_BB_TO_FSB(mp, d) != mp->m_sb.sb_dblocks) {
 497                 xfs_warn(mp, "filesystem size mismatch detected");
 498                 return -EFBIG;
 499         }
 500         error = xfs_buf_read_uncached(mp->m_ddev_targp,
 501                                         d - XFS_FSS_TO_BB(mp, 1),
 502                                         XFS_FSS_TO_BB(mp, 1), 0, &bp, NULL);
 503         if (error) {
 504                 xfs_warn(mp, "last sector read failed");
 505                 return error;
 506         }
 507         xfs_buf_relse(bp);
 508 
 509         if (mp->m_logdev_targp == mp->m_ddev_targp)
 510                 return 0;
 511 
 512         d = (xfs_daddr_t)XFS_FSB_TO_BB(mp, mp->m_sb.sb_logblocks);
 513         if (XFS_BB_TO_FSB(mp, d) != mp->m_sb.sb_logblocks) {
 514                 xfs_warn(mp, "log size mismatch detected");
 515                 return -EFBIG;
 516         }
 517         error = xfs_buf_read_uncached(mp->m_logdev_targp,
 518                                         d - XFS_FSB_TO_BB(mp, 1),
 519                                         XFS_FSB_TO_BB(mp, 1), 0, &bp, NULL);
 520         if (error) {
 521                 xfs_warn(mp, "log device read failed");
 522                 return error;
 523         }
 524         xfs_buf_relse(bp);
 525         return 0;
 526 }
 527 
 528 /*
 529  * Clear the quotaflags in memory and in the superblock.
 530  */
 531 int
 532 xfs_mount_reset_sbqflags(
 533         struct xfs_mount        *mp)
 534 {
 535         mp->m_qflags = 0;
 536 
 537         /* It is OK to look at sb_qflags in the mount path without m_sb_lock. */
 538         if (mp->m_sb.sb_qflags == 0)
 539                 return 0;
 540         spin_lock(&mp->m_sb_lock);
 541         mp->m_sb.sb_qflags = 0;
 542         spin_unlock(&mp->m_sb_lock);
 543 
 544         if (!xfs_fs_writable(mp, SB_FREEZE_WRITE))
 545                 return 0;
 546 
 547         return xfs_sync_sb(mp, false);
 548 }
 549 
 550 uint64_t
 551 xfs_default_resblks(xfs_mount_t *mp)
 552 {
 553         uint64_t resblks;
 554 
 555         /*
 556          * We default to 5% or 8192 fsbs of space reserved, whichever is
 557          * smaller.  This is intended to cover concurrent allocation
 558          * transactions when we initially hit enospc. These each require a 4
 559          * block reservation. Hence by default we cover roughly 2000 concurrent
 560          * allocation reservations.
 561          */
 562         resblks = mp->m_sb.sb_dblocks;
 563         do_div(resblks, 20);
 564         resblks = min_t(uint64_t, resblks, 8192);
 565         return resblks;
 566 }
 567 
 568 /* Ensure the summary counts are correct. */
 569 STATIC int
 570 xfs_check_summary_counts(
 571         struct xfs_mount        *mp)
 572 {
 573         /*
 574          * The AG0 superblock verifier rejects in-progress filesystems,
 575          * so we should never see the flag set this far into mounting.
 576          */
 577         if (mp->m_sb.sb_inprogress) {
 578                 xfs_err(mp, "sb_inprogress set after log recovery??");
 579                 WARN_ON(1);
 580                 return -EFSCORRUPTED;
 581         }
 582 
 583         /*
 584          * Now the log is mounted, we know if it was an unclean shutdown or
 585          * not. If it was, with the first phase of recovery has completed, we
 586          * have consistent AG blocks on disk. We have not recovered EFIs yet,
 587          * but they are recovered transactionally in the second recovery phase
 588          * later.
 589          *
 590          * If the log was clean when we mounted, we can check the summary
 591          * counters.  If any of them are obviously incorrect, we can recompute
 592          * them from the AGF headers in the next step.
 593          */
 594         if (XFS_LAST_UNMOUNT_WAS_CLEAN(mp) &&
 595             (mp->m_sb.sb_fdblocks > mp->m_sb.sb_dblocks ||
 596              !xfs_verify_icount(mp, mp->m_sb.sb_icount) ||
 597              mp->m_sb.sb_ifree > mp->m_sb.sb_icount))
 598                 xfs_fs_mark_sick(mp, XFS_SICK_FS_COUNTERS);
 599 
 600         /*
 601          * We can safely re-initialise incore superblock counters from the
 602          * per-ag data. These may not be correct if the filesystem was not
 603          * cleanly unmounted, so we waited for recovery to finish before doing
 604          * this.
 605          *
 606          * If the filesystem was cleanly unmounted or the previous check did
 607          * not flag anything weird, then we can trust the values in the
 608          * superblock to be correct and we don't need to do anything here.
 609          * Otherwise, recalculate the summary counters.
 610          */
 611         if ((!xfs_sb_version_haslazysbcount(&mp->m_sb) ||
 612              XFS_LAST_UNMOUNT_WAS_CLEAN(mp)) &&
 613             !xfs_fs_has_sickness(mp, XFS_SICK_FS_COUNTERS))
 614                 return 0;
 615 
 616         return xfs_initialize_perag_data(mp, mp->m_sb.sb_agcount);
 617 }
 618 
 619 /*
 620  * This function does the following on an initial mount of a file system:
 621  *      - reads the superblock from disk and init the mount struct
 622  *      - if we're a 32-bit kernel, do a size check on the superblock
 623  *              so we don't mount terabyte filesystems
 624  *      - init mount struct realtime fields
 625  *      - allocate inode hash table for fs
 626  *      - init directory manager
 627  *      - perform recovery and init the log manager
 628  */
 629 int
 630 xfs_mountfs(
 631         struct xfs_mount        *mp)
 632 {
 633         struct xfs_sb           *sbp = &(mp->m_sb);
 634         struct xfs_inode        *rip;
 635         struct xfs_ino_geometry *igeo = M_IGEO(mp);
 636         uint64_t                resblks;
 637         uint                    quotamount = 0;
 638         uint                    quotaflags = 0;
 639         int                     error = 0;
 640 
 641         xfs_sb_mount_common(mp, sbp);
 642 
 643         /*
 644          * Check for a mismatched features2 values.  Older kernels read & wrote
 645          * into the wrong sb offset for sb_features2 on some platforms due to
 646          * xfs_sb_t not being 64bit size aligned when sb_features2 was added,
 647          * which made older superblock reading/writing routines swap it as a
 648          * 64-bit value.
 649          *
 650          * For backwards compatibility, we make both slots equal.
 651          *
 652          * If we detect a mismatched field, we OR the set bits into the existing
 653          * features2 field in case it has already been modified; we don't want
 654          * to lose any features.  We then update the bad location with the ORed
 655          * value so that older kernels will see any features2 flags. The
 656          * superblock writeback code ensures the new sb_features2 is copied to
 657          * sb_bad_features2 before it is logged or written to disk.
 658          */
 659         if (xfs_sb_has_mismatched_features2(sbp)) {
 660                 xfs_warn(mp, "correcting sb_features alignment problem");
 661                 sbp->sb_features2 |= sbp->sb_bad_features2;
 662                 mp->m_update_sb = true;
 663 
 664                 /*
 665                  * Re-check for ATTR2 in case it was found in bad_features2
 666                  * slot.
 667                  */
 668                 if (xfs_sb_version_hasattr2(&mp->m_sb) &&
 669                    !(mp->m_flags & XFS_MOUNT_NOATTR2))
 670                         mp->m_flags |= XFS_MOUNT_ATTR2;
 671         }
 672 
 673         if (xfs_sb_version_hasattr2(&mp->m_sb) &&
 674            (mp->m_flags & XFS_MOUNT_NOATTR2)) {
 675                 xfs_sb_version_removeattr2(&mp->m_sb);
 676                 mp->m_update_sb = true;
 677 
 678                 /* update sb_versionnum for the clearing of the morebits */
 679                 if (!sbp->sb_features2)
 680                         mp->m_update_sb = true;
 681         }
 682 
 683         /* always use v2 inodes by default now */
 684         if (!(mp->m_sb.sb_versionnum & XFS_SB_VERSION_NLINKBIT)) {
 685                 mp->m_sb.sb_versionnum |= XFS_SB_VERSION_NLINKBIT;
 686                 mp->m_update_sb = true;
 687         }
 688 
 689         /*
 690          * Check if sb_agblocks is aligned at stripe boundary
 691          * If sb_agblocks is NOT aligned turn off m_dalign since
 692          * allocator alignment is within an ag, therefore ag has
 693          * to be aligned at stripe boundary.
 694          */
 695         error = xfs_update_alignment(mp);
 696         if (error)
 697                 goto out;
 698 
 699         xfs_alloc_compute_maxlevels(mp);
 700         xfs_bmap_compute_maxlevels(mp, XFS_DATA_FORK);
 701         xfs_bmap_compute_maxlevels(mp, XFS_ATTR_FORK);
 702         xfs_ialloc_setup_geometry(mp);
 703         xfs_rmapbt_compute_maxlevels(mp);
 704         xfs_refcountbt_compute_maxlevels(mp);
 705 
 706         /* enable fail_at_unmount as default */
 707         mp->m_fail_unmount = true;
 708 
 709         error = xfs_sysfs_init(&mp->m_kobj, &xfs_mp_ktype, NULL, mp->m_fsname);
 710         if (error)
 711                 goto out;
 712 
 713         error = xfs_sysfs_init(&mp->m_stats.xs_kobj, &xfs_stats_ktype,
 714                                &mp->m_kobj, "stats");
 715         if (error)
 716                 goto out_remove_sysfs;
 717 
 718         error = xfs_error_sysfs_init(mp);
 719         if (error)
 720                 goto out_del_stats;
 721 
 722         error = xfs_errortag_init(mp);
 723         if (error)
 724                 goto out_remove_error_sysfs;
 725 
 726         error = xfs_uuid_mount(mp);
 727         if (error)
 728                 goto out_remove_errortag;
 729 
 730         /*
 731          * Set the minimum read and write sizes
 732          */
 733         xfs_set_rw_sizes(mp);
 734 
 735         /* set the low space thresholds for dynamic preallocation */
 736         xfs_set_low_space_thresholds(mp);
 737 
 738         /*
 739          * If enabled, sparse inode chunk alignment is expected to match the
 740          * cluster size. Full inode chunk alignment must match the chunk size,
 741          * but that is checked on sb read verification...
 742          */
 743         if (xfs_sb_version_hassparseinodes(&mp->m_sb) &&
 744             mp->m_sb.sb_spino_align !=
 745                         XFS_B_TO_FSBT(mp, igeo->inode_cluster_size_raw)) {
 746                 xfs_warn(mp,
 747         "Sparse inode block alignment (%u) must match cluster size (%llu).",
 748                          mp->m_sb.sb_spino_align,
 749                          XFS_B_TO_FSBT(mp, igeo->inode_cluster_size_raw));
 750                 error = -EINVAL;
 751                 goto out_remove_uuid;
 752         }
 753 
 754         /*
 755          * Check that the data (and log if separate) is an ok size.
 756          */
 757         error = xfs_check_sizes(mp);
 758         if (error)
 759                 goto out_remove_uuid;
 760 
 761         /*
 762          * Initialize realtime fields in the mount structure
 763          */
 764         error = xfs_rtmount_init(mp);
 765         if (error) {
 766                 xfs_warn(mp, "RT mount failed");
 767                 goto out_remove_uuid;
 768         }
 769 
 770         /*
 771          *  Copies the low order bits of the timestamp and the randomly
 772          *  set "sequence" number out of a UUID.
 773          */
 774         mp->m_fixedfsid[0] =
 775                 (get_unaligned_be16(&sbp->sb_uuid.b[8]) << 16) |
 776                  get_unaligned_be16(&sbp->sb_uuid.b[4]);
 777         mp->m_fixedfsid[1] = get_unaligned_be32(&sbp->sb_uuid.b[0]);
 778 
 779         error = xfs_da_mount(mp);
 780         if (error) {
 781                 xfs_warn(mp, "Failed dir/attr init: %d", error);
 782                 goto out_remove_uuid;
 783         }
 784 
 785         /*
 786          * Initialize the precomputed transaction reservations values.
 787          */
 788         xfs_trans_init(mp);
 789 
 790         /*
 791          * Allocate and initialize the per-ag data.
 792          */
 793         error = xfs_initialize_perag(mp, sbp->sb_agcount, &mp->m_maxagi);
 794         if (error) {
 795                 xfs_warn(mp, "Failed per-ag init: %d", error);
 796                 goto out_free_dir;
 797         }
 798 
 799         if (!sbp->sb_logblocks) {
 800                 xfs_warn(mp, "no log defined");
 801                 XFS_ERROR_REPORT("xfs_mountfs", XFS_ERRLEVEL_LOW, mp);
 802                 error = -EFSCORRUPTED;
 803                 goto out_free_perag;
 804         }
 805 
 806         /*
 807          * Log's mount-time initialization. The first part of recovery can place
 808          * some items on the AIL, to be handled when recovery is finished or
 809          * cancelled.
 810          */
 811         error = xfs_log_mount(mp, mp->m_logdev_targp,
 812                               XFS_FSB_TO_DADDR(mp, sbp->sb_logstart),
 813                               XFS_FSB_TO_BB(mp, sbp->sb_logblocks));
 814         if (error) {
 815                 xfs_warn(mp, "log mount failed");
 816                 goto out_fail_wait;
 817         }
 818 
 819         /* Make sure the summary counts are ok. */
 820         error = xfs_check_summary_counts(mp);
 821         if (error)
 822                 goto out_log_dealloc;
 823 
 824         /*
 825          * Get and sanity-check the root inode.
 826          * Save the pointer to it in the mount structure.
 827          */
 828         error = xfs_iget(mp, NULL, sbp->sb_rootino, XFS_IGET_UNTRUSTED,
 829                          XFS_ILOCK_EXCL, &rip);
 830         if (error) {
 831                 xfs_warn(mp,
 832                         "Failed to read root inode 0x%llx, error %d",
 833                         sbp->sb_rootino, -error);
 834                 goto out_log_dealloc;
 835         }
 836 
 837         ASSERT(rip != NULL);
 838 
 839         if (unlikely(!S_ISDIR(VFS_I(rip)->i_mode))) {
 840                 xfs_warn(mp, "corrupted root inode %llu: not a directory",
 841                         (unsigned long long)rip->i_ino);
 842                 xfs_iunlock(rip, XFS_ILOCK_EXCL);
 843                 XFS_ERROR_REPORT("xfs_mountfs_int(2)", XFS_ERRLEVEL_LOW,
 844                                  mp);
 845                 error = -EFSCORRUPTED;
 846                 goto out_rele_rip;
 847         }
 848         mp->m_rootip = rip;     /* save it */
 849 
 850         xfs_iunlock(rip, XFS_ILOCK_EXCL);
 851 
 852         /*
 853          * Initialize realtime inode pointers in the mount structure
 854          */
 855         error = xfs_rtmount_inodes(mp);
 856         if (error) {
 857                 /*
 858                  * Free up the root inode.
 859                  */
 860                 xfs_warn(mp, "failed to read RT inodes");
 861                 goto out_rele_rip;
 862         }
 863 
 864         /*
 865          * If this is a read-only mount defer the superblock updates until
 866          * the next remount into writeable mode.  Otherwise we would never
 867          * perform the update e.g. for the root filesystem.
 868          */
 869         if (mp->m_update_sb && !(mp->m_flags & XFS_MOUNT_RDONLY)) {
 870                 error = xfs_sync_sb(mp, false);
 871                 if (error) {
 872                         xfs_warn(mp, "failed to write sb changes");
 873                         goto out_rtunmount;
 874                 }
 875         }
 876 
 877         /*
 878          * Initialise the XFS quota management subsystem for this mount
 879          */
 880         if (XFS_IS_QUOTA_RUNNING(mp)) {
 881                 error = xfs_qm_newmount(mp, &quotamount, &quotaflags);
 882                 if (error)
 883                         goto out_rtunmount;
 884         } else {
 885                 ASSERT(!XFS_IS_QUOTA_ON(mp));
 886 
 887                 /*
 888                  * If a file system had quotas running earlier, but decided to
 889                  * mount without -o uquota/pquota/gquota options, revoke the
 890                  * quotachecked license.
 891                  */
 892                 if (mp->m_sb.sb_qflags & XFS_ALL_QUOTA_ACCT) {
 893                         xfs_notice(mp, "resetting quota flags");
 894                         error = xfs_mount_reset_sbqflags(mp);
 895                         if (error)
 896                                 goto out_rtunmount;
 897                 }
 898         }
 899 
 900         /*
 901          * Finish recovering the file system.  This part needed to be delayed
 902          * until after the root and real-time bitmap inodes were consistently
 903          * read in.
 904          */
 905         error = xfs_log_mount_finish(mp);
 906         if (error) {
 907                 xfs_warn(mp, "log mount finish failed");
 908                 goto out_rtunmount;
 909         }
 910 
 911         /*
 912          * Now the log is fully replayed, we can transition to full read-only
 913          * mode for read-only mounts. This will sync all the metadata and clean
 914          * the log so that the recovery we just performed does not have to be
 915          * replayed again on the next mount.
 916          *
 917          * We use the same quiesce mechanism as the rw->ro remount, as they are
 918          * semantically identical operations.
 919          */
 920         if ((mp->m_flags & (XFS_MOUNT_RDONLY|XFS_MOUNT_NORECOVERY)) ==
 921                                                         XFS_MOUNT_RDONLY) {
 922                 xfs_quiesce_attr(mp);
 923         }
 924 
 925         /*
 926          * Complete the quota initialisation, post-log-replay component.
 927          */
 928         if (quotamount) {
 929                 ASSERT(mp->m_qflags == 0);
 930                 mp->m_qflags = quotaflags;
 931 
 932                 xfs_qm_mount_quotas(mp);
 933         }
 934 
 935         /*
 936          * Now we are mounted, reserve a small amount of unused space for
 937          * privileged transactions. This is needed so that transaction
 938          * space required for critical operations can dip into this pool
 939          * when at ENOSPC. This is needed for operations like create with
 940          * attr, unwritten extent conversion at ENOSPC, etc. Data allocations
 941          * are not allowed to use this reserved space.
 942          *
 943          * This may drive us straight to ENOSPC on mount, but that implies
 944          * we were already there on the last unmount. Warn if this occurs.
 945          */
 946         if (!(mp->m_flags & XFS_MOUNT_RDONLY)) {
 947                 resblks = xfs_default_resblks(mp);
 948                 error = xfs_reserve_blocks(mp, &resblks, NULL);
 949                 if (error)
 950                         xfs_warn(mp,
 951         "Unable to allocate reserve blocks. Continuing without reserve pool.");
 952 
 953                 /* Recover any CoW blocks that never got remapped. */
 954                 error = xfs_reflink_recover_cow(mp);
 955                 if (error) {
 956                         xfs_err(mp,
 957         "Error %d recovering leftover CoW allocations.", error);
 958                         xfs_force_shutdown(mp, SHUTDOWN_CORRUPT_INCORE);
 959                         goto out_quota;
 960                 }
 961 
 962                 /* Reserve AG blocks for future btree expansion. */
 963                 error = xfs_fs_reserve_ag_blocks(mp);
 964                 if (error && error != -ENOSPC)
 965                         goto out_agresv;
 966         }
 967 
 968         return 0;
 969 
 970  out_agresv:
 971         xfs_fs_unreserve_ag_blocks(mp);
 972  out_quota:
 973         xfs_qm_unmount_quotas(mp);
 974  out_rtunmount:
 975         xfs_rtunmount_inodes(mp);
 976  out_rele_rip:
 977         xfs_irele(rip);
 978         /* Clean out dquots that might be in memory after quotacheck. */
 979         xfs_qm_unmount(mp);
 980         /*
 981          * Cancel all delayed reclaim work and reclaim the inodes directly.
 982          * We have to do this /after/ rtunmount and qm_unmount because those
 983          * two will have scheduled delayed reclaim for the rt/quota inodes.
 984          *
 985          * This is slightly different from the unmountfs call sequence
 986          * because we could be tearing down a partially set up mount.  In
 987          * particular, if log_mount_finish fails we bail out without calling
 988          * qm_unmount_quotas and therefore rely on qm_unmount to release the
 989          * quota inodes.
 990          */
 991         cancel_delayed_work_sync(&mp->m_reclaim_work);
 992         xfs_reclaim_inodes(mp, SYNC_WAIT);
 993         xfs_health_unmount(mp);
 994  out_log_dealloc:
 995         mp->m_flags |= XFS_MOUNT_UNMOUNTING;
 996         xfs_log_mount_cancel(mp);
 997  out_fail_wait:
 998         if (mp->m_logdev_targp && mp->m_logdev_targp != mp->m_ddev_targp)
 999                 xfs_wait_buftarg(mp->m_logdev_targp);
1000         xfs_wait_buftarg(mp->m_ddev_targp);
1001  out_free_perag:
1002         xfs_free_perag(mp);
1003  out_free_dir:
1004         xfs_da_unmount(mp);
1005  out_remove_uuid:
1006         xfs_uuid_unmount(mp);
1007  out_remove_errortag:
1008         xfs_errortag_del(mp);
1009  out_remove_error_sysfs:
1010         xfs_error_sysfs_del(mp);
1011  out_del_stats:
1012         xfs_sysfs_del(&mp->m_stats.xs_kobj);
1013  out_remove_sysfs:
1014         xfs_sysfs_del(&mp->m_kobj);
1015  out:
1016         return error;
1017 }
1018 
1019 /*
1020  * This flushes out the inodes,dquots and the superblock, unmounts the
1021  * log and makes sure that incore structures are freed.
1022  */
1023 void
1024 xfs_unmountfs(
1025         struct xfs_mount        *mp)
1026 {
1027         uint64_t                resblks;
1028         int                     error;
1029 
1030         xfs_stop_block_reaping(mp);
1031         xfs_fs_unreserve_ag_blocks(mp);
1032         xfs_qm_unmount_quotas(mp);
1033         xfs_rtunmount_inodes(mp);
1034         xfs_irele(mp->m_rootip);
1035 
1036         /*
1037          * We can potentially deadlock here if we have an inode cluster
1038          * that has been freed has its buffer still pinned in memory because
1039          * the transaction is still sitting in a iclog. The stale inodes
1040          * on that buffer will have their flush locks held until the
1041          * transaction hits the disk and the callbacks run. the inode
1042          * flush takes the flush lock unconditionally and with nothing to
1043          * push out the iclog we will never get that unlocked. hence we
1044          * need to force the log first.
1045          */
1046         xfs_log_force(mp, XFS_LOG_SYNC);
1047 
1048         /*
1049          * Wait for all busy extents to be freed, including completion of
1050          * any discard operation.
1051          */
1052         xfs_extent_busy_wait_all(mp);
1053         flush_workqueue(xfs_discard_wq);
1054 
1055         /*
1056          * We now need to tell the world we are unmounting. This will allow
1057          * us to detect that the filesystem is going away and we should error
1058          * out anything that we have been retrying in the background. This will
1059          * prevent neverending retries in AIL pushing from hanging the unmount.
1060          */
1061         mp->m_flags |= XFS_MOUNT_UNMOUNTING;
1062 
1063         /*
1064          * Flush all pending changes from the AIL.
1065          */
1066         xfs_ail_push_all_sync(mp->m_ail);
1067 
1068         /*
1069          * And reclaim all inodes.  At this point there should be no dirty
1070          * inodes and none should be pinned or locked, but use synchronous
1071          * reclaim just to be sure. We can stop background inode reclaim
1072          * here as well if it is still running.
1073          */
1074         cancel_delayed_work_sync(&mp->m_reclaim_work);
1075         xfs_reclaim_inodes(mp, SYNC_WAIT);
1076         xfs_health_unmount(mp);
1077 
1078         xfs_qm_unmount(mp);
1079 
1080         /*
1081          * Unreserve any blocks we have so that when we unmount we don't account
1082          * the reserved free space as used. This is really only necessary for
1083          * lazy superblock counting because it trusts the incore superblock
1084          * counters to be absolutely correct on clean unmount.
1085          *
1086          * We don't bother correcting this elsewhere for lazy superblock
1087          * counting because on mount of an unclean filesystem we reconstruct the
1088          * correct counter value and this is irrelevant.
1089          *
1090          * For non-lazy counter filesystems, this doesn't matter at all because
1091          * we only every apply deltas to the superblock and hence the incore
1092          * value does not matter....
1093          */
1094         resblks = 0;
1095         error = xfs_reserve_blocks(mp, &resblks, NULL);
1096         if (error)
1097                 xfs_warn(mp, "Unable to free reserved block pool. "
1098                                 "Freespace may not be correct on next mount.");
1099 
1100         error = xfs_log_sbcount(mp);
1101         if (error)
1102                 xfs_warn(mp, "Unable to update superblock counters. "
1103                                 "Freespace may not be correct on next mount.");
1104 
1105 
1106         xfs_log_unmount(mp);
1107         xfs_da_unmount(mp);
1108         xfs_uuid_unmount(mp);
1109 
1110 #if defined(DEBUG)
1111         xfs_errortag_clearall(mp);
1112 #endif
1113         xfs_free_perag(mp);
1114 
1115         xfs_errortag_del(mp);
1116         xfs_error_sysfs_del(mp);
1117         xfs_sysfs_del(&mp->m_stats.xs_kobj);
1118         xfs_sysfs_del(&mp->m_kobj);
1119 }
1120 
1121 /*
1122  * Determine whether modifications can proceed. The caller specifies the minimum
1123  * freeze level for which modifications should not be allowed. This allows
1124  * certain operations to proceed while the freeze sequence is in progress, if
1125  * necessary.
1126  */
1127 bool
1128 xfs_fs_writable(
1129         struct xfs_mount        *mp,
1130         int                     level)
1131 {
1132         ASSERT(level > SB_UNFROZEN);
1133         if ((mp->m_super->s_writers.frozen >= level) ||
1134             XFS_FORCED_SHUTDOWN(mp) || (mp->m_flags & XFS_MOUNT_RDONLY))
1135                 return false;
1136 
1137         return true;
1138 }
1139 
1140 /*
1141  * xfs_log_sbcount
1142  *
1143  * Sync the superblock counters to disk.
1144  *
1145  * Note this code can be called during the process of freezing, so we use the
1146  * transaction allocator that does not block when the transaction subsystem is
1147  * in its frozen state.
1148  */
1149 int
1150 xfs_log_sbcount(xfs_mount_t *mp)
1151 {
1152         /* allow this to proceed during the freeze sequence... */
1153         if (!xfs_fs_writable(mp, SB_FREEZE_COMPLETE))
1154                 return 0;
1155 
1156         /*
1157          * we don't need to do this if we are updating the superblock
1158          * counters on every modification.
1159          */
1160         if (!xfs_sb_version_haslazysbcount(&mp->m_sb))
1161                 return 0;
1162 
1163         return xfs_sync_sb(mp, true);
1164 }
1165 
1166 /*
1167  * Deltas for the inode count are +/-64, hence we use a large batch size
1168  * of 128 so we don't need to take the counter lock on every update.
1169  */
1170 #define XFS_ICOUNT_BATCH        128
1171 int
1172 xfs_mod_icount(
1173         struct xfs_mount        *mp,
1174         int64_t                 delta)
1175 {
1176         percpu_counter_add_batch(&mp->m_icount, delta, XFS_ICOUNT_BATCH);
1177         if (__percpu_counter_compare(&mp->m_icount, 0, XFS_ICOUNT_BATCH) < 0) {
1178                 ASSERT(0);
1179                 percpu_counter_add(&mp->m_icount, -delta);
1180                 return -EINVAL;
1181         }
1182         return 0;
1183 }
1184 
1185 int
1186 xfs_mod_ifree(
1187         struct xfs_mount        *mp,
1188         int64_t                 delta)
1189 {
1190         percpu_counter_add(&mp->m_ifree, delta);
1191         if (percpu_counter_compare(&mp->m_ifree, 0) < 0) {
1192                 ASSERT(0);
1193                 percpu_counter_add(&mp->m_ifree, -delta);
1194                 return -EINVAL;
1195         }
1196         return 0;
1197 }
1198 
1199 /*
1200  * Deltas for the block count can vary from 1 to very large, but lock contention
1201  * only occurs on frequent small block count updates such as in the delayed
1202  * allocation path for buffered writes (page a time updates). Hence we set
1203  * a large batch count (1024) to minimise global counter updates except when
1204  * we get near to ENOSPC and we have to be very accurate with our updates.
1205  */
1206 #define XFS_FDBLOCKS_BATCH      1024
1207 int
1208 xfs_mod_fdblocks(
1209         struct xfs_mount        *mp,
1210         int64_t                 delta,
1211         bool                    rsvd)
1212 {
1213         int64_t                 lcounter;
1214         long long               res_used;
1215         s32                     batch;
1216 
1217         if (delta > 0) {
1218                 /*
1219                  * If the reserve pool is depleted, put blocks back into it
1220                  * first. Most of the time the pool is full.
1221                  */
1222                 if (likely(mp->m_resblks == mp->m_resblks_avail)) {
1223                         percpu_counter_add(&mp->m_fdblocks, delta);
1224                         return 0;
1225                 }
1226 
1227                 spin_lock(&mp->m_sb_lock);
1228                 res_used = (long long)(mp->m_resblks - mp->m_resblks_avail);
1229 
1230                 if (res_used > delta) {
1231                         mp->m_resblks_avail += delta;
1232                 } else {
1233                         delta -= res_used;
1234                         mp->m_resblks_avail = mp->m_resblks;
1235                         percpu_counter_add(&mp->m_fdblocks, delta);
1236                 }
1237                 spin_unlock(&mp->m_sb_lock);
1238                 return 0;
1239         }
1240 
1241         /*
1242          * Taking blocks away, need to be more accurate the closer we
1243          * are to zero.
1244          *
1245          * If the counter has a value of less than 2 * max batch size,
1246          * then make everything serialise as we are real close to
1247          * ENOSPC.
1248          */
1249         if (__percpu_counter_compare(&mp->m_fdblocks, 2 * XFS_FDBLOCKS_BATCH,
1250                                      XFS_FDBLOCKS_BATCH) < 0)
1251                 batch = 1;
1252         else
1253                 batch = XFS_FDBLOCKS_BATCH;
1254 
1255         percpu_counter_add_batch(&mp->m_fdblocks, delta, batch);
1256         if (__percpu_counter_compare(&mp->m_fdblocks, mp->m_alloc_set_aside,
1257                                      XFS_FDBLOCKS_BATCH) >= 0) {
1258                 /* we had space! */
1259                 return 0;
1260         }
1261 
1262         /*
1263          * lock up the sb for dipping into reserves before releasing the space
1264          * that took us to ENOSPC.
1265          */
1266         spin_lock(&mp->m_sb_lock);
1267         percpu_counter_add(&mp->m_fdblocks, -delta);
1268         if (!rsvd)
1269                 goto fdblocks_enospc;
1270 
1271         lcounter = (long long)mp->m_resblks_avail + delta;
1272         if (lcounter >= 0) {
1273                 mp->m_resblks_avail = lcounter;
1274                 spin_unlock(&mp->m_sb_lock);
1275                 return 0;
1276         }
1277         printk_once(KERN_WARNING
1278                 "Filesystem \"%s\": reserve blocks depleted! "
1279                 "Consider increasing reserve pool size.",
1280                 mp->m_fsname);
1281 fdblocks_enospc:
1282         spin_unlock(&mp->m_sb_lock);
1283         return -ENOSPC;
1284 }
1285 
1286 int
1287 xfs_mod_frextents(
1288         struct xfs_mount        *mp,
1289         int64_t                 delta)
1290 {
1291         int64_t                 lcounter;
1292         int                     ret = 0;
1293 
1294         spin_lock(&mp->m_sb_lock);
1295         lcounter = mp->m_sb.sb_frextents + delta;
1296         if (lcounter < 0)
1297                 ret = -ENOSPC;
1298         else
1299                 mp->m_sb.sb_frextents = lcounter;
1300         spin_unlock(&mp->m_sb_lock);
1301         return ret;
1302 }
1303 
1304 /*
1305  * xfs_getsb() is called to obtain the buffer for the superblock.
1306  * The buffer is returned locked and read in from disk.
1307  * The buffer should be released with a call to xfs_brelse().
1308  */
1309 struct xfs_buf *
1310 xfs_getsb(
1311         struct xfs_mount        *mp)
1312 {
1313         struct xfs_buf          *bp = mp->m_sb_bp;
1314 
1315         xfs_buf_lock(bp);
1316         xfs_buf_hold(bp);
1317         ASSERT(bp->b_flags & XBF_DONE);
1318         return bp;
1319 }
1320 
1321 /*
1322  * Used to free the superblock along various error paths.
1323  */
1324 void
1325 xfs_freesb(
1326         struct xfs_mount        *mp)
1327 {
1328         struct xfs_buf          *bp = mp->m_sb_bp;
1329 
1330         xfs_buf_lock(bp);
1331         mp->m_sb_bp = NULL;
1332         xfs_buf_relse(bp);
1333 }
1334 
1335 /*
1336  * If the underlying (data/log/rt) device is readonly, there are some
1337  * operations that cannot proceed.
1338  */
1339 int
1340 xfs_dev_is_read_only(
1341         struct xfs_mount        *mp,
1342         char                    *message)
1343 {
1344         if (xfs_readonly_buftarg(mp->m_ddev_targp) ||
1345             xfs_readonly_buftarg(mp->m_logdev_targp) ||
1346             (mp->m_rtdev_targp && xfs_readonly_buftarg(mp->m_rtdev_targp))) {
1347                 xfs_notice(mp, "%s required on read-only device.", message);
1348                 xfs_notice(mp, "write access unavailable, cannot proceed.");
1349                 return -EROFS;
1350         }
1351         return 0;
1352 }
1353 
1354 /* Force the summary counters to be recalculated at next mount. */
1355 void
1356 xfs_force_summary_recalc(
1357         struct xfs_mount        *mp)
1358 {
1359         if (!xfs_sb_version_haslazysbcount(&mp->m_sb))
1360                 return;
1361 
1362         xfs_fs_mark_sick(mp, XFS_SICK_FS_COUNTERS);
1363 }
1364 
1365 /*
1366  * Update the in-core delayed block counter.
1367  *
1368  * We prefer to update the counter without having to take a spinlock for every
1369  * counter update (i.e. batching).  Each change to delayed allocation
1370  * reservations can change can easily exceed the default percpu counter
1371  * batching, so we use a larger batch factor here.
1372  *
1373  * Note that we don't currently have any callers requiring fast summation
1374  * (e.g. percpu_counter_read) so we can use a big batch value here.
1375  */
1376 #define XFS_DELALLOC_BATCH      (4096)
1377 void
1378 xfs_mod_delalloc(
1379         struct xfs_mount        *mp,
1380         int64_t                 delta)
1381 {
1382         percpu_counter_add_batch(&mp->m_delalloc_blks, delta,
1383                         XFS_DELALLOC_BATCH);
1384 }
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root/fs/xfs/xfs_mount.c

DEFINITIONS
