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Linux/fs/xfs/xfs_mount.c

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  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_defer.h"
 16 #include "xfs_da_format.h"
 17 #include "xfs_da_btree.h"
 18 #include "xfs_inode.h"
 19 #include "xfs_dir2.h"
 20 #include "xfs_ialloc.h"
 21 #include "xfs_alloc.h"
 22 #include "xfs_rtalloc.h"
 23 #include "xfs_bmap.h"
 24 #include "xfs_trans.h"
 25 #include "xfs_trans_priv.h"
 26 #include "xfs_log.h"
 27 #include "xfs_error.h"
 28 #include "xfs_quota.h"
 29 #include "xfs_fsops.h"
 30 #include "xfs_trace.h"
 31 #include "xfs_icache.h"
 32 #include "xfs_sysfs.h"
 33 #include "xfs_rmap_btree.h"
 34 #include "xfs_refcount_btree.h"
 35 #include "xfs_reflink.h"
 36 #include "xfs_extent_busy.h"
 37 
 38 
 39 static DEFINE_MUTEX(xfs_uuid_table_mutex);
 40 static int xfs_uuid_table_size;
 41 static uuid_t *xfs_uuid_table;
 42 
 43 void
 44 xfs_uuid_table_free(void)
 45 {
 46         if (xfs_uuid_table_size == 0)
 47                 return;
 48         kmem_free(xfs_uuid_table);
 49         xfs_uuid_table = NULL;
 50         xfs_uuid_table_size = 0;
 51 }
 52 
 53 /*
 54  * See if the UUID is unique among mounted XFS filesystems.
 55  * Mount fails if UUID is nil or a FS with the same UUID is already mounted.
 56  */
 57 STATIC int
 58 xfs_uuid_mount(
 59         struct xfs_mount        *mp)
 60 {
 61         uuid_t                  *uuid = &mp->m_sb.sb_uuid;
 62         int                     hole, i;
 63 
 64         /* Publish UUID in struct super_block */
 65         uuid_copy(&mp->m_super->s_uuid, uuid);
 66 
 67         if (mp->m_flags & XFS_MOUNT_NOUUID)
 68                 return 0;
 69 
 70         if (uuid_is_null(uuid)) {
 71                 xfs_warn(mp, "Filesystem has null UUID - can't mount");
 72                 return -EINVAL;
 73         }
 74 
 75         mutex_lock(&xfs_uuid_table_mutex);
 76         for (i = 0, hole = -1; i < xfs_uuid_table_size; i++) {
 77                 if (uuid_is_null(&xfs_uuid_table[i])) {
 78                         hole = i;
 79                         continue;
 80                 }
 81                 if (uuid_equal(uuid, &xfs_uuid_table[i]))
 82                         goto out_duplicate;
 83         }
 84 
 85         if (hole < 0) {
 86                 xfs_uuid_table = kmem_realloc(xfs_uuid_table,
 87                         (xfs_uuid_table_size + 1) * sizeof(*xfs_uuid_table),
 88                         KM_SLEEP);
 89                 hole = xfs_uuid_table_size++;
 90         }
 91         xfs_uuid_table[hole] = *uuid;
 92         mutex_unlock(&xfs_uuid_table_mutex);
 93 
 94         return 0;
 95 
 96  out_duplicate:
 97         mutex_unlock(&xfs_uuid_table_mutex);
 98         xfs_warn(mp, "Filesystem has duplicate UUID %pU - can't mount", uuid);
 99         return -EINVAL;
100 }
101 
102 STATIC void
103 xfs_uuid_unmount(
104         struct xfs_mount        *mp)
105 {
106         uuid_t                  *uuid = &mp->m_sb.sb_uuid;
107         int                     i;
108 
109         if (mp->m_flags & XFS_MOUNT_NOUUID)
110                 return;
111 
112         mutex_lock(&xfs_uuid_table_mutex);
113         for (i = 0; i < xfs_uuid_table_size; i++) {
114                 if (uuid_is_null(&xfs_uuid_table[i]))
115                         continue;
116                 if (!uuid_equal(uuid, &xfs_uuid_table[i]))
117                         continue;
118                 memset(&xfs_uuid_table[i], 0, sizeof(uuid_t));
119                 break;
120         }
121         ASSERT(i < xfs_uuid_table_size);
122         mutex_unlock(&xfs_uuid_table_mutex);
123 }
124 
125 
126 STATIC void
127 __xfs_free_perag(
128         struct rcu_head *head)
129 {
130         struct xfs_perag *pag = container_of(head, struct xfs_perag, rcu_head);
131 
132         ASSERT(atomic_read(&pag->pag_ref) == 0);
133         kmem_free(pag);
134 }
135 
136 /*
137  * Free up the per-ag resources associated with the mount structure.
138  */
139 STATIC void
140 xfs_free_perag(
141         xfs_mount_t     *mp)
142 {
143         xfs_agnumber_t  agno;
144         struct xfs_perag *pag;
145 
146         for (agno = 0; agno < mp->m_sb.sb_agcount; agno++) {
147                 spin_lock(&mp->m_perag_lock);
148                 pag = radix_tree_delete(&mp->m_perag_tree, agno);
149                 spin_unlock(&mp->m_perag_lock);
150                 ASSERT(pag);
151                 ASSERT(atomic_read(&pag->pag_ref) == 0);
152                 xfs_iunlink_destroy(pag);
153                 xfs_buf_hash_destroy(pag);
154                 mutex_destroy(&pag->pag_ici_reclaim_lock);
155                 call_rcu(&pag->rcu_head, __xfs_free_perag);
156         }
157 }
158 
159 /*
160  * Check size of device based on the (data/realtime) block count.
161  * Note: this check is used by the growfs code as well as mount.
162  */
163 int
164 xfs_sb_validate_fsb_count(
165         xfs_sb_t        *sbp,
166         uint64_t        nblocks)
167 {
168         ASSERT(PAGE_SHIFT >= sbp->sb_blocklog);
169         ASSERT(sbp->sb_blocklog >= BBSHIFT);
170 
171         /* Limited by ULONG_MAX of page cache index */
172         if (nblocks >> (PAGE_SHIFT - sbp->sb_blocklog) > ULONG_MAX)
173                 return -EFBIG;
174         return 0;
175 }
176 
177 int
178 xfs_initialize_perag(
179         xfs_mount_t     *mp,
180         xfs_agnumber_t  agcount,
181         xfs_agnumber_t  *maxagi)
182 {
183         xfs_agnumber_t  index;
184         xfs_agnumber_t  first_initialised = NULLAGNUMBER;
185         xfs_perag_t     *pag;
186         int             error = -ENOMEM;
187 
188         /*
189          * Walk the current per-ag tree so we don't try to initialise AGs
190          * that already exist (growfs case). Allocate and insert all the
191          * AGs we don't find ready for initialisation.
192          */
193         for (index = 0; index < agcount; index++) {
194                 pag = xfs_perag_get(mp, index);
195                 if (pag) {
196                         xfs_perag_put(pag);
197                         continue;
198                 }
199 
200                 pag = kmem_zalloc(sizeof(*pag), KM_MAYFAIL);
201                 if (!pag)
202                         goto out_unwind_new_pags;
203                 pag->pag_agno = index;
204                 pag->pag_mount = mp;
205                 spin_lock_init(&pag->pag_ici_lock);
206                 mutex_init(&pag->pag_ici_reclaim_lock);
207                 INIT_RADIX_TREE(&pag->pag_ici_root, GFP_ATOMIC);
208                 if (xfs_buf_hash_init(pag))
209                         goto out_free_pag;
210                 init_waitqueue_head(&pag->pagb_wait);
211                 spin_lock_init(&pag->pagb_lock);
212                 pag->pagb_count = 0;
213                 pag->pagb_tree = RB_ROOT;
214 
215                 if (radix_tree_preload(GFP_NOFS))
216                         goto out_hash_destroy;
217 
218                 spin_lock(&mp->m_perag_lock);
219                 if (radix_tree_insert(&mp->m_perag_tree, index, pag)) {
220                         BUG();
221                         spin_unlock(&mp->m_perag_lock);
222                         radix_tree_preload_end();
223                         error = -EEXIST;
224                         goto out_hash_destroy;
225                 }
226                 spin_unlock(&mp->m_perag_lock);
227                 radix_tree_preload_end();
228                 /* first new pag is fully initialized */
229                 if (first_initialised == NULLAGNUMBER)
230                         first_initialised = index;
231                 error = xfs_iunlink_init(pag);
232                 if (error)
233                         goto out_hash_destroy;
234         }
235 
236         index = xfs_set_inode_alloc(mp, agcount);
237 
238         if (maxagi)
239                 *maxagi = index;
240 
241         mp->m_ag_prealloc_blocks = xfs_prealloc_blocks(mp);
242         return 0;
243 
244 out_hash_destroy:
245         xfs_buf_hash_destroy(pag);
246 out_free_pag:
247         mutex_destroy(&pag->pag_ici_reclaim_lock);
248         kmem_free(pag);
249 out_unwind_new_pags:
250         /* unwind any prior newly initialized pags */
251         for (index = first_initialised; index < agcount; index++) {
252                 pag = radix_tree_delete(&mp->m_perag_tree, index);
253                 if (!pag)
254                         break;
255                 xfs_buf_hash_destroy(pag);
256                 xfs_iunlink_destroy(pag);
257                 mutex_destroy(&pag->pag_ici_reclaim_lock);
258                 kmem_free(pag);
259         }
260         return error;
261 }
262 
263 /*
264  * xfs_readsb
265  *
266  * Does the initial read of the superblock.
267  */
268 int
269 xfs_readsb(
270         struct xfs_mount *mp,
271         int             flags)
272 {
273         unsigned int    sector_size;
274         struct xfs_buf  *bp;
275         struct xfs_sb   *sbp = &mp->m_sb;
276         int             error;
277         int             loud = !(flags & XFS_MFSI_QUIET);
278         const struct xfs_buf_ops *buf_ops;
279 
280         ASSERT(mp->m_sb_bp == NULL);
281         ASSERT(mp->m_ddev_targp != NULL);
282 
283         /*
284          * For the initial read, we must guess at the sector
285          * size based on the block device.  It's enough to
286          * get the sb_sectsize out of the superblock and
287          * then reread with the proper length.
288          * We don't verify it yet, because it may not be complete.
289          */
290         sector_size = xfs_getsize_buftarg(mp->m_ddev_targp);
291         buf_ops = NULL;
292 
293         /*
294          * Allocate a (locked) buffer to hold the superblock. This will be kept
295          * around at all times to optimize access to the superblock. Therefore,
296          * set XBF_NO_IOACCT to make sure it doesn't hold the buftarg count
297          * elevated.
298          */
299 reread:
300         error = xfs_buf_read_uncached(mp->m_ddev_targp, XFS_SB_DADDR,
301                                       BTOBB(sector_size), XBF_NO_IOACCT, &bp,
302                                       buf_ops);
303         if (error) {
304                 if (loud)
305                         xfs_warn(mp, "SB validate failed with error %d.", error);
306                 /* bad CRC means corrupted metadata */
307                 if (error == -EFSBADCRC)
308                         error = -EFSCORRUPTED;
309                 return error;
310         }
311 
312         /*
313          * Initialize the mount structure from the superblock.
314          */
315         xfs_sb_from_disk(sbp, XFS_BUF_TO_SBP(bp));
316 
317         /*
318          * If we haven't validated the superblock, do so now before we try
319          * to check the sector size and reread the superblock appropriately.
320          */
321         if (sbp->sb_magicnum != XFS_SB_MAGIC) {
322                 if (loud)
323                         xfs_warn(mp, "Invalid superblock magic number");
324                 error = -EINVAL;
325                 goto release_buf;
326         }
327 
328         /*
329          * We must be able to do sector-sized and sector-aligned IO.
330          */
331         if (sector_size > sbp->sb_sectsize) {
332                 if (loud)
333                         xfs_warn(mp, "device supports %u byte sectors (not %u)",
334                                 sector_size, sbp->sb_sectsize);
335                 error = -ENOSYS;
336                 goto release_buf;
337         }
338 
339         if (buf_ops == NULL) {
340                 /*
341                  * Re-read the superblock so the buffer is correctly sized,
342                  * and properly verified.
343                  */
344                 xfs_buf_relse(bp);
345                 sector_size = sbp->sb_sectsize;
346                 buf_ops = loud ? &xfs_sb_buf_ops : &xfs_sb_quiet_buf_ops;
347                 goto reread;
348         }
349 
350         xfs_reinit_percpu_counters(mp);
351 
352         /* no need to be quiet anymore, so reset the buf ops */
353         bp->b_ops = &xfs_sb_buf_ops;
354 
355         mp->m_sb_bp = bp;
356         xfs_buf_unlock(bp);
357         return 0;
358 
359 release_buf:
360         xfs_buf_relse(bp);
361         return error;
362 }
363 
364 /*
365  * Update alignment values based on mount options and sb values
366  */
367 STATIC int
368 xfs_update_alignment(xfs_mount_t *mp)
369 {
370         xfs_sb_t        *sbp = &(mp->m_sb);
371 
372         if (mp->m_dalign) {
373                 /*
374                  * If stripe unit and stripe width are not multiples
375                  * of the fs blocksize turn off alignment.
376                  */
377                 if ((BBTOB(mp->m_dalign) & mp->m_blockmask) ||
378                     (BBTOB(mp->m_swidth) & mp->m_blockmask)) {
379                         xfs_warn(mp,
380                 "alignment check failed: sunit/swidth vs. blocksize(%d)",
381                                 sbp->sb_blocksize);
382                         return -EINVAL;
383                 } else {
384                         /*
385                          * Convert the stripe unit and width to FSBs.
386                          */
387                         mp->m_dalign = XFS_BB_TO_FSBT(mp, mp->m_dalign);
388                         if (mp->m_dalign && (sbp->sb_agblocks % mp->m_dalign)) {
389                                 xfs_warn(mp,
390                         "alignment check failed: sunit/swidth vs. agsize(%d)",
391                                          sbp->sb_agblocks);
392                                 return -EINVAL;
393                         } else if (mp->m_dalign) {
394                                 mp->m_swidth = XFS_BB_TO_FSBT(mp, mp->m_swidth);
395                         } else {
396                                 xfs_warn(mp,
397                         "alignment check failed: sunit(%d) less than bsize(%d)",
398                                          mp->m_dalign, sbp->sb_blocksize);
399                                 return -EINVAL;
400                         }
401                 }
402 
403                 /*
404                  * Update superblock with new values
405                  * and log changes
406                  */
407                 if (xfs_sb_version_hasdalign(sbp)) {
408                         if (sbp->sb_unit != mp->m_dalign) {
409                                 sbp->sb_unit = mp->m_dalign;
410                                 mp->m_update_sb = true;
411                         }
412                         if (sbp->sb_width != mp->m_swidth) {
413                                 sbp->sb_width = mp->m_swidth;
414                                 mp->m_update_sb = true;
415                         }
416                 } else {
417                         xfs_warn(mp,
418         "cannot change alignment: superblock does not support data alignment");
419                         return -EINVAL;
420                 }
421         } else if ((mp->m_flags & XFS_MOUNT_NOALIGN) != XFS_MOUNT_NOALIGN &&
422                     xfs_sb_version_hasdalign(&mp->m_sb)) {
423                         mp->m_dalign = sbp->sb_unit;
424                         mp->m_swidth = sbp->sb_width;
425         }
426 
427         return 0;
428 }
429 
430 /*
431  * Set the maximum inode count for this filesystem
432  */
433 STATIC void
434 xfs_set_maxicount(xfs_mount_t *mp)
435 {
436         xfs_sb_t        *sbp = &(mp->m_sb);
437         uint64_t        icount;
438 
439         if (sbp->sb_imax_pct) {
440                 /*
441                  * Make sure the maximum inode count is a multiple
442                  * of the units we allocate inodes in.
443                  */
444                 icount = sbp->sb_dblocks * sbp->sb_imax_pct;
445                 do_div(icount, 100);
446                 do_div(icount, mp->m_ialloc_blks);
447                 mp->m_maxicount = (icount * mp->m_ialloc_blks)  <<
448                                    sbp->sb_inopblog;
449         } else {
450                 mp->m_maxicount = 0;
451         }
452 }
453 
454 /*
455  * Set the default minimum read and write sizes unless
456  * already specified in a mount option.
457  * We use smaller I/O sizes when the file system
458  * is being used for NFS service (wsync mount option).
459  */
460 STATIC void
461 xfs_set_rw_sizes(xfs_mount_t *mp)
462 {
463         xfs_sb_t        *sbp = &(mp->m_sb);
464         int             readio_log, writeio_log;
465 
466         if (!(mp->m_flags & XFS_MOUNT_DFLT_IOSIZE)) {
467                 if (mp->m_flags & XFS_MOUNT_WSYNC) {
468                         readio_log = XFS_WSYNC_READIO_LOG;
469                         writeio_log = XFS_WSYNC_WRITEIO_LOG;
470                 } else {
471                         readio_log = XFS_READIO_LOG_LARGE;
472                         writeio_log = XFS_WRITEIO_LOG_LARGE;
473                 }
474         } else {
475                 readio_log = mp->m_readio_log;
476                 writeio_log = mp->m_writeio_log;
477         }
478 
479         if (sbp->sb_blocklog > readio_log) {
480                 mp->m_readio_log = sbp->sb_blocklog;
481         } else {
482                 mp->m_readio_log = readio_log;
483         }
484         mp->m_readio_blocks = 1 << (mp->m_readio_log - sbp->sb_blocklog);
485         if (sbp->sb_blocklog > writeio_log) {
486                 mp->m_writeio_log = sbp->sb_blocklog;
487         } else {
488                 mp->m_writeio_log = writeio_log;
489         }
490         mp->m_writeio_blocks = 1 << (mp->m_writeio_log - sbp->sb_blocklog);
491 }
492 
493 /*
494  * precalculate the low space thresholds for dynamic speculative preallocation.
495  */
496 void
497 xfs_set_low_space_thresholds(
498         struct xfs_mount        *mp)
499 {
500         int i;
501 
502         for (i = 0; i < XFS_LOWSP_MAX; i++) {
503                 uint64_t space = mp->m_sb.sb_dblocks;
504 
505                 do_div(space, 100);
506                 mp->m_low_space[i] = space * (i + 1);
507         }
508 }
509 
510 
511 /*
512  * Set whether we're using inode alignment.
513  */
514 STATIC void
515 xfs_set_inoalignment(xfs_mount_t *mp)
516 {
517         if (xfs_sb_version_hasalign(&mp->m_sb) &&
518                 mp->m_sb.sb_inoalignmt >= xfs_icluster_size_fsb(mp))
519                 mp->m_inoalign_mask = mp->m_sb.sb_inoalignmt - 1;
520         else
521                 mp->m_inoalign_mask = 0;
522         /*
523          * If we are using stripe alignment, check whether
524          * the stripe unit is a multiple of the inode alignment
525          */
526         if (mp->m_dalign && mp->m_inoalign_mask &&
527             !(mp->m_dalign & mp->m_inoalign_mask))
528                 mp->m_sinoalign = mp->m_dalign;
529         else
530                 mp->m_sinoalign = 0;
531 }
532 
533 /*
534  * Check that the data (and log if separate) is an ok size.
535  */
536 STATIC int
537 xfs_check_sizes(
538         struct xfs_mount *mp)
539 {
540         struct xfs_buf  *bp;
541         xfs_daddr_t     d;
542         int             error;
543 
544         d = (xfs_daddr_t)XFS_FSB_TO_BB(mp, mp->m_sb.sb_dblocks);
545         if (XFS_BB_TO_FSB(mp, d) != mp->m_sb.sb_dblocks) {
546                 xfs_warn(mp, "filesystem size mismatch detected");
547                 return -EFBIG;
548         }
549         error = xfs_buf_read_uncached(mp->m_ddev_targp,
550                                         d - XFS_FSS_TO_BB(mp, 1),
551                                         XFS_FSS_TO_BB(mp, 1), 0, &bp, NULL);
552         if (error) {
553                 xfs_warn(mp, "last sector read failed");
554                 return error;
555         }
556         xfs_buf_relse(bp);
557 
558         if (mp->m_logdev_targp == mp->m_ddev_targp)
559                 return 0;
560 
561         d = (xfs_daddr_t)XFS_FSB_TO_BB(mp, mp->m_sb.sb_logblocks);
562         if (XFS_BB_TO_FSB(mp, d) != mp->m_sb.sb_logblocks) {
563                 xfs_warn(mp, "log size mismatch detected");
564                 return -EFBIG;
565         }
566         error = xfs_buf_read_uncached(mp->m_logdev_targp,
567                                         d - XFS_FSB_TO_BB(mp, 1),
568                                         XFS_FSB_TO_BB(mp, 1), 0, &bp, NULL);
569         if (error) {
570                 xfs_warn(mp, "log device read failed");
571                 return error;
572         }
573         xfs_buf_relse(bp);
574         return 0;
575 }
576 
577 /*
578  * Clear the quotaflags in memory and in the superblock.
579  */
580 int
581 xfs_mount_reset_sbqflags(
582         struct xfs_mount        *mp)
583 {
584         mp->m_qflags = 0;
585 
586         /* It is OK to look at sb_qflags in the mount path without m_sb_lock. */
587         if (mp->m_sb.sb_qflags == 0)
588                 return 0;
589         spin_lock(&mp->m_sb_lock);
590         mp->m_sb.sb_qflags = 0;
591         spin_unlock(&mp->m_sb_lock);
592 
593         if (!xfs_fs_writable(mp, SB_FREEZE_WRITE))
594                 return 0;
595 
596         return xfs_sync_sb(mp, false);
597 }
598 
599 uint64_t
600 xfs_default_resblks(xfs_mount_t *mp)
601 {
602         uint64_t resblks;
603 
604         /*
605          * We default to 5% or 8192 fsbs of space reserved, whichever is
606          * smaller.  This is intended to cover concurrent allocation
607          * transactions when we initially hit enospc. These each require a 4
608          * block reservation. Hence by default we cover roughly 2000 concurrent
609          * allocation reservations.
610          */
611         resblks = mp->m_sb.sb_dblocks;
612         do_div(resblks, 20);
613         resblks = min_t(uint64_t, resblks, 8192);
614         return resblks;
615 }
616 
617 /* Ensure the summary counts are correct. */
618 STATIC int
619 xfs_check_summary_counts(
620         struct xfs_mount        *mp)
621 {
622         /*
623          * The AG0 superblock verifier rejects in-progress filesystems,
624          * so we should never see the flag set this far into mounting.
625          */
626         if (mp->m_sb.sb_inprogress) {
627                 xfs_err(mp, "sb_inprogress set after log recovery??");
628                 WARN_ON(1);
629                 return -EFSCORRUPTED;
630         }
631 
632         /*
633          * Now the log is mounted, we know if it was an unclean shutdown or
634          * not. If it was, with the first phase of recovery has completed, we
635          * have consistent AG blocks on disk. We have not recovered EFIs yet,
636          * but they are recovered transactionally in the second recovery phase
637          * later.
638          *
639          * If the log was clean when we mounted, we can check the summary
640          * counters.  If any of them are obviously incorrect, we can recompute
641          * them from the AGF headers in the next step.
642          */
643         if (XFS_LAST_UNMOUNT_WAS_CLEAN(mp) &&
644             (mp->m_sb.sb_fdblocks > mp->m_sb.sb_dblocks ||
645              !xfs_verify_icount(mp, mp->m_sb.sb_icount) ||
646              mp->m_sb.sb_ifree > mp->m_sb.sb_icount))
647                 mp->m_flags |= XFS_MOUNT_BAD_SUMMARY;
648 
649         /*
650          * We can safely re-initialise incore superblock counters from the
651          * per-ag data. These may not be correct if the filesystem was not
652          * cleanly unmounted, so we waited for recovery to finish before doing
653          * this.
654          *
655          * If the filesystem was cleanly unmounted or the previous check did
656          * not flag anything weird, then we can trust the values in the
657          * superblock to be correct and we don't need to do anything here.
658          * Otherwise, recalculate the summary counters.
659          */
660         if ((!xfs_sb_version_haslazysbcount(&mp->m_sb) ||
661              XFS_LAST_UNMOUNT_WAS_CLEAN(mp)) &&
662             !(mp->m_flags & XFS_MOUNT_BAD_SUMMARY))
663                 return 0;
664 
665         return xfs_initialize_perag_data(mp, mp->m_sb.sb_agcount);
666 }
667 
668 /*
669  * This function does the following on an initial mount of a file system:
670  *      - reads the superblock from disk and init the mount struct
671  *      - if we're a 32-bit kernel, do a size check on the superblock
672  *              so we don't mount terabyte filesystems
673  *      - init mount struct realtime fields
674  *      - allocate inode hash table for fs
675  *      - init directory manager
676  *      - perform recovery and init the log manager
677  */
678 int
679 xfs_mountfs(
680         struct xfs_mount        *mp)
681 {
682         struct xfs_sb           *sbp = &(mp->m_sb);
683         struct xfs_inode        *rip;
684         uint64_t                resblks;
685         uint                    quotamount = 0;
686         uint                    quotaflags = 0;
687         int                     error = 0;
688 
689         xfs_sb_mount_common(mp, sbp);
690 
691         /*
692          * Check for a mismatched features2 values.  Older kernels read & wrote
693          * into the wrong sb offset for sb_features2 on some platforms due to
694          * xfs_sb_t not being 64bit size aligned when sb_features2 was added,
695          * which made older superblock reading/writing routines swap it as a
696          * 64-bit value.
697          *
698          * For backwards compatibility, we make both slots equal.
699          *
700          * If we detect a mismatched field, we OR the set bits into the existing
701          * features2 field in case it has already been modified; we don't want
702          * to lose any features.  We then update the bad location with the ORed
703          * value so that older kernels will see any features2 flags. The
704          * superblock writeback code ensures the new sb_features2 is copied to
705          * sb_bad_features2 before it is logged or written to disk.
706          */
707         if (xfs_sb_has_mismatched_features2(sbp)) {
708                 xfs_warn(mp, "correcting sb_features alignment problem");
709                 sbp->sb_features2 |= sbp->sb_bad_features2;
710                 mp->m_update_sb = true;
711 
712                 /*
713                  * Re-check for ATTR2 in case it was found in bad_features2
714                  * slot.
715                  */
716                 if (xfs_sb_version_hasattr2(&mp->m_sb) &&
717                    !(mp->m_flags & XFS_MOUNT_NOATTR2))
718                         mp->m_flags |= XFS_MOUNT_ATTR2;
719         }
720 
721         if (xfs_sb_version_hasattr2(&mp->m_sb) &&
722            (mp->m_flags & XFS_MOUNT_NOATTR2)) {
723                 xfs_sb_version_removeattr2(&mp->m_sb);
724                 mp->m_update_sb = true;
725 
726                 /* update sb_versionnum for the clearing of the morebits */
727                 if (!sbp->sb_features2)
728                         mp->m_update_sb = true;
729         }
730 
731         /* always use v2 inodes by default now */
732         if (!(mp->m_sb.sb_versionnum & XFS_SB_VERSION_NLINKBIT)) {
733                 mp->m_sb.sb_versionnum |= XFS_SB_VERSION_NLINKBIT;
734                 mp->m_update_sb = true;
735         }
736 
737         /*
738          * Check if sb_agblocks is aligned at stripe boundary
739          * If sb_agblocks is NOT aligned turn off m_dalign since
740          * allocator alignment is within an ag, therefore ag has
741          * to be aligned at stripe boundary.
742          */
743         error = xfs_update_alignment(mp);
744         if (error)
745                 goto out;
746 
747         xfs_alloc_compute_maxlevels(mp);
748         xfs_bmap_compute_maxlevels(mp, XFS_DATA_FORK);
749         xfs_bmap_compute_maxlevels(mp, XFS_ATTR_FORK);
750         xfs_ialloc_compute_maxlevels(mp);
751         xfs_rmapbt_compute_maxlevels(mp);
752         xfs_refcountbt_compute_maxlevels(mp);
753 
754         xfs_set_maxicount(mp);
755 
756         /* enable fail_at_unmount as default */
757         mp->m_fail_unmount = true;
758 
759         error = xfs_sysfs_init(&mp->m_kobj, &xfs_mp_ktype, NULL, mp->m_fsname);
760         if (error)
761                 goto out;
762 
763         error = xfs_sysfs_init(&mp->m_stats.xs_kobj, &xfs_stats_ktype,
764                                &mp->m_kobj, "stats");
765         if (error)
766                 goto out_remove_sysfs;
767 
768         error = xfs_error_sysfs_init(mp);
769         if (error)
770                 goto out_del_stats;
771 
772         error = xfs_errortag_init(mp);
773         if (error)
774                 goto out_remove_error_sysfs;
775 
776         error = xfs_uuid_mount(mp);
777         if (error)
778                 goto out_remove_errortag;
779 
780         /*
781          * Set the minimum read and write sizes
782          */
783         xfs_set_rw_sizes(mp);
784 
785         /* set the low space thresholds for dynamic preallocation */
786         xfs_set_low_space_thresholds(mp);
787 
788         /*
789          * Set the inode cluster size.
790          * This may still be overridden by the file system
791          * block size if it is larger than the chosen cluster size.
792          *
793          * For v5 filesystems, scale the cluster size with the inode size to
794          * keep a constant ratio of inode per cluster buffer, but only if mkfs
795          * has set the inode alignment value appropriately for larger cluster
796          * sizes.
797          */
798         mp->m_inode_cluster_size = XFS_INODE_BIG_CLUSTER_SIZE;
799         if (xfs_sb_version_hascrc(&mp->m_sb)) {
800                 int     new_size = mp->m_inode_cluster_size;
801 
802                 new_size *= mp->m_sb.sb_inodesize / XFS_DINODE_MIN_SIZE;
803                 if (mp->m_sb.sb_inoalignmt >= XFS_B_TO_FSBT(mp, new_size))
804                         mp->m_inode_cluster_size = new_size;
805         }
806         mp->m_blocks_per_cluster = xfs_icluster_size_fsb(mp);
807         mp->m_inodes_per_cluster = XFS_FSB_TO_INO(mp, mp->m_blocks_per_cluster);
808         mp->m_cluster_align = xfs_ialloc_cluster_alignment(mp);
809         mp->m_cluster_align_inodes = XFS_FSB_TO_INO(mp, mp->m_cluster_align);
810 
811         /*
812          * If enabled, sparse inode chunk alignment is expected to match the
813          * cluster size. Full inode chunk alignment must match the chunk size,
814          * but that is checked on sb read verification...
815          */
816         if (xfs_sb_version_hassparseinodes(&mp->m_sb) &&
817             mp->m_sb.sb_spino_align !=
818                         XFS_B_TO_FSBT(mp, mp->m_inode_cluster_size)) {
819                 xfs_warn(mp,
820         "Sparse inode block alignment (%u) must match cluster size (%llu).",
821                          mp->m_sb.sb_spino_align,
822                          XFS_B_TO_FSBT(mp, mp->m_inode_cluster_size));
823                 error = -EINVAL;
824                 goto out_remove_uuid;
825         }
826 
827         /*
828          * Set inode alignment fields
829          */
830         xfs_set_inoalignment(mp);
831 
832         /*
833          * Check that the data (and log if separate) is an ok size.
834          */
835         error = xfs_check_sizes(mp);
836         if (error)
837                 goto out_remove_uuid;
838 
839         /*
840          * Initialize realtime fields in the mount structure
841          */
842         error = xfs_rtmount_init(mp);
843         if (error) {
844                 xfs_warn(mp, "RT mount failed");
845                 goto out_remove_uuid;
846         }
847 
848         /*
849          *  Copies the low order bits of the timestamp and the randomly
850          *  set "sequence" number out of a UUID.
851          */
852         mp->m_fixedfsid[0] =
853                 (get_unaligned_be16(&sbp->sb_uuid.b[8]) << 16) |
854                  get_unaligned_be16(&sbp->sb_uuid.b[4]);
855         mp->m_fixedfsid[1] = get_unaligned_be32(&sbp->sb_uuid.b[0]);
856 
857         error = xfs_da_mount(mp);
858         if (error) {
859                 xfs_warn(mp, "Failed dir/attr init: %d", error);
860                 goto out_remove_uuid;
861         }
862 
863         /*
864          * Initialize the precomputed transaction reservations values.
865          */
866         xfs_trans_init(mp);
867 
868         /*
869          * Allocate and initialize the per-ag data.
870          */
871         error = xfs_initialize_perag(mp, sbp->sb_agcount, &mp->m_maxagi);
872         if (error) {
873                 xfs_warn(mp, "Failed per-ag init: %d", error);
874                 goto out_free_dir;
875         }
876 
877         if (!sbp->sb_logblocks) {
878                 xfs_warn(mp, "no log defined");
879                 XFS_ERROR_REPORT("xfs_mountfs", XFS_ERRLEVEL_LOW, mp);
880                 error = -EFSCORRUPTED;
881                 goto out_free_perag;
882         }
883 
884         /*
885          * Log's mount-time initialization. The first part of recovery can place
886          * some items on the AIL, to be handled when recovery is finished or
887          * cancelled.
888          */
889         error = xfs_log_mount(mp, mp->m_logdev_targp,
890                               XFS_FSB_TO_DADDR(mp, sbp->sb_logstart),
891                               XFS_FSB_TO_BB(mp, sbp->sb_logblocks));
892         if (error) {
893                 xfs_warn(mp, "log mount failed");
894                 goto out_fail_wait;
895         }
896 
897         /* Make sure the summary counts are ok. */
898         error = xfs_check_summary_counts(mp);
899         if (error)
900                 goto out_log_dealloc;
901 
902         /*
903          * Get and sanity-check the root inode.
904          * Save the pointer to it in the mount structure.
905          */
906         error = xfs_iget(mp, NULL, sbp->sb_rootino, XFS_IGET_UNTRUSTED,
907                          XFS_ILOCK_EXCL, &rip);
908         if (error) {
909                 xfs_warn(mp,
910                         "Failed to read root inode 0x%llx, error %d",
911                         sbp->sb_rootino, -error);
912                 goto out_log_dealloc;
913         }
914 
915         ASSERT(rip != NULL);
916 
917         if (unlikely(!S_ISDIR(VFS_I(rip)->i_mode))) {
918                 xfs_warn(mp, "corrupted root inode %llu: not a directory",
919                         (unsigned long long)rip->i_ino);
920                 xfs_iunlock(rip, XFS_ILOCK_EXCL);
921                 XFS_ERROR_REPORT("xfs_mountfs_int(2)", XFS_ERRLEVEL_LOW,
922                                  mp);
923                 error = -EFSCORRUPTED;
924                 goto out_rele_rip;
925         }
926         mp->m_rootip = rip;     /* save it */
927 
928         xfs_iunlock(rip, XFS_ILOCK_EXCL);
929 
930         /*
931          * Initialize realtime inode pointers in the mount structure
932          */
933         error = xfs_rtmount_inodes(mp);
934         if (error) {
935                 /*
936                  * Free up the root inode.
937                  */
938                 xfs_warn(mp, "failed to read RT inodes");
939                 goto out_rele_rip;
940         }
941 
942         /*
943          * If this is a read-only mount defer the superblock updates until
944          * the next remount into writeable mode.  Otherwise we would never
945          * perform the update e.g. for the root filesystem.
946          */
947         if (mp->m_update_sb && !(mp->m_flags & XFS_MOUNT_RDONLY)) {
948                 error = xfs_sync_sb(mp, false);
949                 if (error) {
950                         xfs_warn(mp, "failed to write sb changes");
951                         goto out_rtunmount;
952                 }
953         }
954 
955         /*
956          * Initialise the XFS quota management subsystem for this mount
957          */
958         if (XFS_IS_QUOTA_RUNNING(mp)) {
959                 error = xfs_qm_newmount(mp, &quotamount, &quotaflags);
960                 if (error)
961                         goto out_rtunmount;
962         } else {
963                 ASSERT(!XFS_IS_QUOTA_ON(mp));
964 
965                 /*
966                  * If a file system had quotas running earlier, but decided to
967                  * mount without -o uquota/pquota/gquota options, revoke the
968                  * quotachecked license.
969                  */
970                 if (mp->m_sb.sb_qflags & XFS_ALL_QUOTA_ACCT) {
971                         xfs_notice(mp, "resetting quota flags");
972                         error = xfs_mount_reset_sbqflags(mp);
973                         if (error)
974                                 goto out_rtunmount;
975                 }
976         }
977 
978         /*
979          * Finish recovering the file system.  This part needed to be delayed
980          * until after the root and real-time bitmap inodes were consistently
981          * read in.
982          */
983         error = xfs_log_mount_finish(mp);
984         if (error) {
985                 xfs_warn(mp, "log mount finish failed");
986                 goto out_rtunmount;
987         }
988 
989         /*
990          * Now the log is fully replayed, we can transition to full read-only
991          * mode for read-only mounts. This will sync all the metadata and clean
992          * the log so that the recovery we just performed does not have to be
993          * replayed again on the next mount.
994          *
995          * We use the same quiesce mechanism as the rw->ro remount, as they are
996          * semantically identical operations.
997          */
998         if ((mp->m_flags & (XFS_MOUNT_RDONLY|XFS_MOUNT_NORECOVERY)) ==
999                                                         XFS_MOUNT_RDONLY) {
1000                 xfs_quiesce_attr(mp);
1001         }
1002 
1003         /*
1004          * Complete the quota initialisation, post-log-replay component.
1005          */
1006         if (quotamount) {
1007                 ASSERT(mp->m_qflags == 0);
1008                 mp->m_qflags = quotaflags;
1009 
1010                 xfs_qm_mount_quotas(mp);
1011         }
1012 
1013         /*
1014          * Now we are mounted, reserve a small amount of unused space for
1015          * privileged transactions. This is needed so that transaction
1016          * space required for critical operations can dip into this pool
1017          * when at ENOSPC. This is needed for operations like create with
1018          * attr, unwritten extent conversion at ENOSPC, etc. Data allocations
1019          * are not allowed to use this reserved space.
1020          *
1021          * This may drive us straight to ENOSPC on mount, but that implies
1022          * we were already there on the last unmount. Warn if this occurs.
1023          */
1024         if (!(mp->m_flags & XFS_MOUNT_RDONLY)) {
1025                 resblks = xfs_default_resblks(mp);
1026                 error = xfs_reserve_blocks(mp, &resblks, NULL);
1027                 if (error)
1028                         xfs_warn(mp,
1029         "Unable to allocate reserve blocks. Continuing without reserve pool.");
1030 
1031                 /* Recover any CoW blocks that never got remapped. */
1032                 error = xfs_reflink_recover_cow(mp);
1033                 if (error) {
1034                         xfs_err(mp,
1035         "Error %d recovering leftover CoW allocations.", error);
1036                         xfs_force_shutdown(mp, SHUTDOWN_CORRUPT_INCORE);
1037                         goto out_quota;
1038                 }
1039 
1040                 /* Reserve AG blocks for future btree expansion. */
1041                 error = xfs_fs_reserve_ag_blocks(mp);
1042                 if (error && error != -ENOSPC)
1043                         goto out_agresv;
1044         }
1045 
1046         return 0;
1047 
1048  out_agresv:
1049         xfs_fs_unreserve_ag_blocks(mp);
1050  out_quota:
1051         xfs_qm_unmount_quotas(mp);
1052  out_rtunmount:
1053         xfs_rtunmount_inodes(mp);
1054  out_rele_rip:
1055         xfs_irele(rip);
1056         /* Clean out dquots that might be in memory after quotacheck. */
1057         xfs_qm_unmount(mp);
1058         /*
1059          * Cancel all delayed reclaim work and reclaim the inodes directly.
1060          * We have to do this /after/ rtunmount and qm_unmount because those
1061          * two will have scheduled delayed reclaim for the rt/quota inodes.
1062          *
1063          * This is slightly different from the unmountfs call sequence
1064          * because we could be tearing down a partially set up mount.  In
1065          * particular, if log_mount_finish fails we bail out without calling
1066          * qm_unmount_quotas and therefore rely on qm_unmount to release the
1067          * quota inodes.
1068          */
1069         cancel_delayed_work_sync(&mp->m_reclaim_work);
1070         xfs_reclaim_inodes(mp, SYNC_WAIT);
1071  out_log_dealloc:
1072         mp->m_flags |= XFS_MOUNT_UNMOUNTING;
1073         xfs_log_mount_cancel(mp);
1074  out_fail_wait:
1075         if (mp->m_logdev_targp && mp->m_logdev_targp != mp->m_ddev_targp)
1076                 xfs_wait_buftarg(mp->m_logdev_targp);
1077         xfs_wait_buftarg(mp->m_ddev_targp);
1078  out_free_perag:
1079         xfs_free_perag(mp);
1080  out_free_dir:
1081         xfs_da_unmount(mp);
1082  out_remove_uuid:
1083         xfs_uuid_unmount(mp);
1084  out_remove_errortag:
1085         xfs_errortag_del(mp);
1086  out_remove_error_sysfs:
1087         xfs_error_sysfs_del(mp);
1088  out_del_stats:
1089         xfs_sysfs_del(&mp->m_stats.xs_kobj);
1090  out_remove_sysfs:
1091         xfs_sysfs_del(&mp->m_kobj);
1092  out:
1093         return error;
1094 }
1095 
1096 /*
1097  * This flushes out the inodes,dquots and the superblock, unmounts the
1098  * log and makes sure that incore structures are freed.
1099  */
1100 void
1101 xfs_unmountfs(
1102         struct xfs_mount        *mp)
1103 {
1104         uint64_t                resblks;
1105         int                     error;
1106 
1107         xfs_icache_disable_reclaim(mp);
1108         xfs_fs_unreserve_ag_blocks(mp);
1109         xfs_qm_unmount_quotas(mp);
1110         xfs_rtunmount_inodes(mp);
1111         xfs_irele(mp->m_rootip);
1112 
1113         /*
1114          * We can potentially deadlock here if we have an inode cluster
1115          * that has been freed has its buffer still pinned in memory because
1116          * the transaction is still sitting in a iclog. The stale inodes
1117          * on that buffer will have their flush locks held until the
1118          * transaction hits the disk and the callbacks run. the inode
1119          * flush takes the flush lock unconditionally and with nothing to
1120          * push out the iclog we will never get that unlocked. hence we
1121          * need to force the log first.
1122          */
1123         xfs_log_force(mp, XFS_LOG_SYNC);
1124 
1125         /*
1126          * Wait for all busy extents to be freed, including completion of
1127          * any discard operation.
1128          */
1129         xfs_extent_busy_wait_all(mp);
1130         flush_workqueue(xfs_discard_wq);
1131 
1132         /*
1133          * We now need to tell the world we are unmounting. This will allow
1134          * us to detect that the filesystem is going away and we should error
1135          * out anything that we have been retrying in the background. This will
1136          * prevent neverending retries in AIL pushing from hanging the unmount.
1137          */
1138         mp->m_flags |= XFS_MOUNT_UNMOUNTING;
1139 
1140         /*
1141          * Flush all pending changes from the AIL.
1142          */
1143         xfs_ail_push_all_sync(mp->m_ail);
1144 
1145         /*
1146          * And reclaim all inodes.  At this point there should be no dirty
1147          * inodes and none should be pinned or locked, but use synchronous
1148          * reclaim just to be sure. We can stop background inode reclaim
1149          * here as well if it is still running.
1150          */
1151         cancel_delayed_work_sync(&mp->m_reclaim_work);
1152         xfs_reclaim_inodes(mp, SYNC_WAIT);
1153 
1154         xfs_qm_unmount(mp);
1155 
1156         /*
1157          * Unreserve any blocks we have so that when we unmount we don't account
1158          * the reserved free space as used. This is really only necessary for
1159          * lazy superblock counting because it trusts the incore superblock
1160          * counters to be absolutely correct on clean unmount.
1161          *
1162          * We don't bother correcting this elsewhere for lazy superblock
1163          * counting because on mount of an unclean filesystem we reconstruct the
1164          * correct counter value and this is irrelevant.
1165          *
1166          * For non-lazy counter filesystems, this doesn't matter at all because
1167          * we only every apply deltas to the superblock and hence the incore
1168          * value does not matter....
1169          */
1170         resblks = 0;
1171         error = xfs_reserve_blocks(mp, &resblks, NULL);
1172         if (error)
1173                 xfs_warn(mp, "Unable to free reserved block pool. "
1174                                 "Freespace may not be correct on next mount.");
1175 
1176         error = xfs_log_sbcount(mp);
1177         if (error)
1178                 xfs_warn(mp, "Unable to update superblock counters. "
1179                                 "Freespace may not be correct on next mount.");
1180 
1181 
1182         xfs_log_unmount(mp);
1183         xfs_da_unmount(mp);
1184         xfs_uuid_unmount(mp);
1185 
1186 #if defined(DEBUG)
1187         xfs_errortag_clearall(mp);
1188 #endif
1189         xfs_free_perag(mp);
1190 
1191         xfs_errortag_del(mp);
1192         xfs_error_sysfs_del(mp);
1193         xfs_sysfs_del(&mp->m_stats.xs_kobj);
1194         xfs_sysfs_del(&mp->m_kobj);
1195 }
1196 
1197 /*
1198  * Determine whether modifications can proceed. The caller specifies the minimum
1199  * freeze level for which modifications should not be allowed. This allows
1200  * certain operations to proceed while the freeze sequence is in progress, if
1201  * necessary.
1202  */
1203 bool
1204 xfs_fs_writable(
1205         struct xfs_mount        *mp,
1206         int                     level)
1207 {
1208         ASSERT(level > SB_UNFROZEN);
1209         if ((mp->m_super->s_writers.frozen >= level) ||
1210             XFS_FORCED_SHUTDOWN(mp) || (mp->m_flags & XFS_MOUNT_RDONLY))
1211                 return false;
1212 
1213         return true;
1214 }
1215 
1216 /*
1217  * xfs_log_sbcount
1218  *
1219  * Sync the superblock counters to disk.
1220  *
1221  * Note this code can be called during the process of freezing, so we use the
1222  * transaction allocator that does not block when the transaction subsystem is
1223  * in its frozen state.
1224  */
1225 int
1226 xfs_log_sbcount(xfs_mount_t *mp)
1227 {
1228         /* allow this to proceed during the freeze sequence... */
1229         if (!xfs_fs_writable(mp, SB_FREEZE_COMPLETE))
1230                 return 0;
1231 
1232         /*
1233          * we don't need to do this if we are updating the superblock
1234          * counters on every modification.
1235          */
1236         if (!xfs_sb_version_haslazysbcount(&mp->m_sb))
1237                 return 0;
1238 
1239         return xfs_sync_sb(mp, true);
1240 }
1241 
1242 /*
1243  * Deltas for the inode count are +/-64, hence we use a large batch size
1244  * of 128 so we don't need to take the counter lock on every update.
1245  */
1246 #define XFS_ICOUNT_BATCH        128
1247 int
1248 xfs_mod_icount(
1249         struct xfs_mount        *mp,
1250         int64_t                 delta)
1251 {
1252         percpu_counter_add_batch(&mp->m_icount, delta, XFS_ICOUNT_BATCH);
1253         if (__percpu_counter_compare(&mp->m_icount, 0, XFS_ICOUNT_BATCH) < 0) {
1254                 ASSERT(0);
1255                 percpu_counter_add(&mp->m_icount, -delta);
1256                 return -EINVAL;
1257         }
1258         return 0;
1259 }
1260 
1261 int
1262 xfs_mod_ifree(
1263         struct xfs_mount        *mp,
1264         int64_t                 delta)
1265 {
1266         percpu_counter_add(&mp->m_ifree, delta);
1267         if (percpu_counter_compare(&mp->m_ifree, 0) < 0) {
1268                 ASSERT(0);
1269                 percpu_counter_add(&mp->m_ifree, -delta);
1270                 return -EINVAL;
1271         }
1272         return 0;
1273 }
1274 
1275 /*
1276  * Deltas for the block count can vary from 1 to very large, but lock contention
1277  * only occurs on frequent small block count updates such as in the delayed
1278  * allocation path for buffered writes (page a time updates). Hence we set
1279  * a large batch count (1024) to minimise global counter updates except when
1280  * we get near to ENOSPC and we have to be very accurate with our updates.
1281  */
1282 #define XFS_FDBLOCKS_BATCH      1024
1283 int
1284 xfs_mod_fdblocks(
1285         struct xfs_mount        *mp,
1286         int64_t                 delta,
1287         bool                    rsvd)
1288 {
1289         int64_t                 lcounter;
1290         long long               res_used;
1291         s32                     batch;
1292 
1293         if (delta > 0) {
1294                 /*
1295                  * If the reserve pool is depleted, put blocks back into it
1296                  * first. Most of the time the pool is full.
1297                  */
1298                 if (likely(mp->m_resblks == mp->m_resblks_avail)) {
1299                         percpu_counter_add(&mp->m_fdblocks, delta);
1300                         return 0;
1301                 }
1302 
1303                 spin_lock(&mp->m_sb_lock);
1304                 res_used = (long long)(mp->m_resblks - mp->m_resblks_avail);
1305 
1306                 if (res_used > delta) {
1307                         mp->m_resblks_avail += delta;
1308                 } else {
1309                         delta -= res_used;
1310                         mp->m_resblks_avail = mp->m_resblks;
1311                         percpu_counter_add(&mp->m_fdblocks, delta);
1312                 }
1313                 spin_unlock(&mp->m_sb_lock);
1314                 return 0;
1315         }
1316 
1317         /*
1318          * Taking blocks away, need to be more accurate the closer we
1319          * are to zero.
1320          *
1321          * If the counter has a value of less than 2 * max batch size,
1322          * then make everything serialise as we are real close to
1323          * ENOSPC.
1324          */
1325         if (__percpu_counter_compare(&mp->m_fdblocks, 2 * XFS_FDBLOCKS_BATCH,
1326                                      XFS_FDBLOCKS_BATCH) < 0)
1327                 batch = 1;
1328         else
1329                 batch = XFS_FDBLOCKS_BATCH;
1330 
1331         percpu_counter_add_batch(&mp->m_fdblocks, delta, batch);
1332         if (__percpu_counter_compare(&mp->m_fdblocks, mp->m_alloc_set_aside,
1333                                      XFS_FDBLOCKS_BATCH) >= 0) {
1334                 /* we had space! */
1335                 return 0;
1336         }
1337 
1338         /*
1339          * lock up the sb for dipping into reserves before releasing the space
1340          * that took us to ENOSPC.
1341          */
1342         spin_lock(&mp->m_sb_lock);
1343         percpu_counter_add(&mp->m_fdblocks, -delta);
1344         if (!rsvd)
1345                 goto fdblocks_enospc;
1346 
1347         lcounter = (long long)mp->m_resblks_avail + delta;
1348         if (lcounter >= 0) {
1349                 mp->m_resblks_avail = lcounter;
1350                 spin_unlock(&mp->m_sb_lock);
1351                 return 0;
1352         }
1353         printk_once(KERN_WARNING
1354                 "Filesystem \"%s\": reserve blocks depleted! "
1355                 "Consider increasing reserve pool size.",
1356                 mp->m_fsname);
1357 fdblocks_enospc:
1358         spin_unlock(&mp->m_sb_lock);
1359         return -ENOSPC;
1360 }
1361 
1362 int
1363 xfs_mod_frextents(
1364         struct xfs_mount        *mp,
1365         int64_t                 delta)
1366 {
1367         int64_t                 lcounter;
1368         int                     ret = 0;
1369 
1370         spin_lock(&mp->m_sb_lock);
1371         lcounter = mp->m_sb.sb_frextents + delta;
1372         if (lcounter < 0)
1373                 ret = -ENOSPC;
1374         else
1375                 mp->m_sb.sb_frextents = lcounter;
1376         spin_unlock(&mp->m_sb_lock);
1377         return ret;
1378 }
1379 
1380 /*
1381  * xfs_getsb() is called to obtain the buffer for the superblock.
1382  * The buffer is returned locked and read in from disk.
1383  * The buffer should be released with a call to xfs_brelse().
1384  *
1385  * If the flags parameter is BUF_TRYLOCK, then we'll only return
1386  * the superblock buffer if it can be locked without sleeping.
1387  * If it can't then we'll return NULL.
1388  */
1389 struct xfs_buf *
1390 xfs_getsb(
1391         struct xfs_mount        *mp,
1392         int                     flags)
1393 {
1394         struct xfs_buf          *bp = mp->m_sb_bp;
1395 
1396         if (!xfs_buf_trylock(bp)) {
1397                 if (flags & XBF_TRYLOCK)
1398                         return NULL;
1399                 xfs_buf_lock(bp);
1400         }
1401 
1402         xfs_buf_hold(bp);
1403         ASSERT(bp->b_flags & XBF_DONE);
1404         return bp;
1405 }
1406 
1407 /*
1408  * Used to free the superblock along various error paths.
1409  */
1410 void
1411 xfs_freesb(
1412         struct xfs_mount        *mp)
1413 {
1414         struct xfs_buf          *bp = mp->m_sb_bp;
1415 
1416         xfs_buf_lock(bp);
1417         mp->m_sb_bp = NULL;
1418         xfs_buf_relse(bp);
1419 }
1420 
1421 /*
1422  * If the underlying (data/log/rt) device is readonly, there are some
1423  * operations that cannot proceed.
1424  */
1425 int
1426 xfs_dev_is_read_only(
1427         struct xfs_mount        *mp,
1428         char                    *message)
1429 {
1430         if (xfs_readonly_buftarg(mp->m_ddev_targp) ||
1431             xfs_readonly_buftarg(mp->m_logdev_targp) ||
1432             (mp->m_rtdev_targp && xfs_readonly_buftarg(mp->m_rtdev_targp))) {
1433                 xfs_notice(mp, "%s required on read-only device.", message);
1434                 xfs_notice(mp, "write access unavailable, cannot proceed.");
1435                 return -EROFS;
1436         }
1437         return 0;
1438 }
1439 
1440 /* Force the summary counters to be recalculated at next mount. */
1441 void
1442 xfs_force_summary_recalc(
1443         struct xfs_mount        *mp)
1444 {
1445         if (!xfs_sb_version_haslazysbcount(&mp->m_sb))
1446                 return;
1447 
1448         spin_lock(&mp->m_sb_lock);
1449         mp->m_flags |= XFS_MOUNT_BAD_SUMMARY;
1450         spin_unlock(&mp->m_sb_lock);
1451 }
1452 

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