2 * Copyright (c) 2000-2005 Silicon Graphics, Inc.
5 * This program is free software; you can redistribute it and/or
6 * modify it under the terms of the GNU General Public License as
7 * published by the Free Software Foundation.
9 * This program is distributed in the hope that it would be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, write the Free Software Foundation,
16 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
20 #include "xfs_types.h"
23 #include "xfs_trans.h"
24 #include "xfs_trans_priv.h"
27 #include "xfs_mount.h"
28 #include "xfs_bmap_btree.h"
29 #include "xfs_inode.h"
30 #include "xfs_dinode.h"
31 #include "xfs_error.h"
32 #include "xfs_filestream.h"
33 #include "xfs_vnodeops.h"
34 #include "xfs_inode_item.h"
35 #include "xfs_quota.h"
36 #include "xfs_trace.h"
37 #include "xfs_fsops.h"
39 #include <linux/kthread.h>
40 #include <linux/freezer.h>
42 struct workqueue_struct *xfs_syncd_wq; /* sync workqueue */
45 * The inode lookup is done in batches to keep the amount of lock traffic and
46 * radix tree lookups to a minimum. The batch size is a trade off between
47 * lookup reduction and stack usage. This is in the reclaim path, so we can't
50 #define XFS_LOOKUP_BATCH 32
53 xfs_inode_ag_walk_grab(
56 struct inode *inode = VFS_I(ip);
58 ASSERT(rcu_read_lock_held());
61 * check for stale RCU freed inode
63 * If the inode has been reallocated, it doesn't matter if it's not in
64 * the AG we are walking - we are walking for writeback, so if it
65 * passes all the "valid inode" checks and is dirty, then we'll write
66 * it back anyway. If it has been reallocated and still being
67 * initialised, the XFS_INEW check below will catch it.
69 spin_lock(&ip->i_flags_lock);
71 goto out_unlock_noent;
73 /* avoid new or reclaimable inodes. Leave for reclaim code to flush */
74 if (__xfs_iflags_test(ip, XFS_INEW | XFS_IRECLAIMABLE | XFS_IRECLAIM))
75 goto out_unlock_noent;
76 spin_unlock(&ip->i_flags_lock);
78 /* nothing to sync during shutdown */
79 if (XFS_FORCED_SHUTDOWN(ip->i_mount))
82 /* If we can't grab the inode, it must on it's way to reclaim. */
86 if (is_bad_inode(inode)) {
95 spin_unlock(&ip->i_flags_lock);
101 struct xfs_mount *mp,
102 struct xfs_perag *pag,
103 int (*execute)(struct xfs_inode *ip,
104 struct xfs_perag *pag, int flags),
107 uint32_t first_index;
119 struct xfs_inode *batch[XFS_LOOKUP_BATCH];
124 nr_found = radix_tree_gang_lookup(&pag->pag_ici_root,
125 (void **)batch, first_index,
133 * Grab the inodes before we drop the lock. if we found
134 * nothing, nr == 0 and the loop will be skipped.
136 for (i = 0; i < nr_found; i++) {
137 struct xfs_inode *ip = batch[i];
139 if (done || xfs_inode_ag_walk_grab(ip))
143 * Update the index for the next lookup. Catch
144 * overflows into the next AG range which can occur if
145 * we have inodes in the last block of the AG and we
146 * are currently pointing to the last inode.
148 * Because we may see inodes that are from the wrong AG
149 * due to RCU freeing and reallocation, only update the
150 * index if it lies in this AG. It was a race that lead
151 * us to see this inode, so another lookup from the
152 * same index will not find it again.
154 if (XFS_INO_TO_AGNO(mp, ip->i_ino) != pag->pag_agno)
156 first_index = XFS_INO_TO_AGINO(mp, ip->i_ino + 1);
157 if (first_index < XFS_INO_TO_AGINO(mp, ip->i_ino))
161 /* unlock now we've grabbed the inodes. */
164 for (i = 0; i < nr_found; i++) {
167 error = execute(batch[i], pag, flags);
169 if (error == EAGAIN) {
173 if (error && last_error != EFSCORRUPTED)
177 /* bail out if the filesystem is corrupted. */
178 if (error == EFSCORRUPTED)
183 } while (nr_found && !done);
193 xfs_inode_ag_iterator(
194 struct xfs_mount *mp,
195 int (*execute)(struct xfs_inode *ip,
196 struct xfs_perag *pag, int flags),
199 struct xfs_perag *pag;
205 while ((pag = xfs_perag_get(mp, ag))) {
206 ag = pag->pag_agno + 1;
207 error = xfs_inode_ag_walk(mp, pag, execute, flags);
211 if (error == EFSCORRUPTED)
215 return XFS_ERROR(last_error);
220 struct xfs_inode *ip,
221 struct xfs_perag *pag,
224 struct inode *inode = VFS_I(ip);
225 struct address_space *mapping = inode->i_mapping;
228 if (!mapping_tagged(mapping, PAGECACHE_TAG_DIRTY))
231 if (!xfs_ilock_nowait(ip, XFS_IOLOCK_SHARED)) {
232 if (flags & SYNC_TRYLOCK)
234 xfs_ilock(ip, XFS_IOLOCK_SHARED);
237 error = xfs_flush_pages(ip, 0, -1, (flags & SYNC_WAIT) ?
238 0 : XBF_ASYNC, FI_NONE);
239 xfs_iunlock(ip, XFS_IOLOCK_SHARED);
244 * Write out pagecache data for the whole filesystem.
248 struct xfs_mount *mp,
253 ASSERT((flags & ~(SYNC_TRYLOCK|SYNC_WAIT)) == 0);
255 error = xfs_inode_ag_iterator(mp, xfs_sync_inode_data, flags);
257 return XFS_ERROR(error);
259 xfs_log_force(mp, (flags & SYNC_WAIT) ? XFS_LOG_SYNC : 0);
265 struct xfs_mount *mp)
271 * If the buffer is pinned then push on the log so we won't get stuck
272 * waiting in the write for someone, maybe ourselves, to flush the log.
274 * Even though we just pushed the log above, we did not have the
275 * superblock buffer locked at that point so it can become pinned in
276 * between there and here.
278 bp = xfs_getsb(mp, 0);
279 if (xfs_buf_ispinned(bp))
280 xfs_log_force(mp, 0);
281 error = xfs_bwrite(bp);
287 * When remounting a filesystem read-only or freezing the filesystem, we have
288 * two phases to execute. This first phase is syncing the data before we
289 * quiesce the filesystem, and the second is flushing all the inodes out after
290 * we've waited for all the transactions created by the first phase to
291 * complete. The second phase ensures that the inodes are written to their
292 * location on disk rather than just existing in transactions in the log. This
293 * means after a quiesce there is no log replay required to write the inodes to
294 * disk (this is the main difference between a sync and a quiesce).
297 * First stage of freeze - no writers will make progress now we are here,
298 * so we flush delwri and delalloc buffers here, then wait for all I/O to
299 * complete. Data is frozen at that point. Metadata is not frozen,
300 * transactions can still occur here so don't bother emptying the AIL
301 * because it'll just get dirty again.
305 struct xfs_mount *mp)
307 int error, error2 = 0;
309 /* force out the log */
310 xfs_log_force(mp, XFS_LOG_SYNC);
312 /* write superblock and hoover up shutdown errors */
313 error = xfs_sync_fsdata(mp);
315 /* mark the log as covered if needed */
316 if (xfs_log_need_covered(mp))
317 error2 = xfs_fs_log_dummy(mp);
319 return error ? error : error2;
323 * Second stage of a quiesce. The data is already synced, now we have to take
324 * care of the metadata. New transactions are already blocked, so we need to
325 * wait for any remaining transactions to drain out before proceeding.
329 struct xfs_mount *mp)
333 /* wait for all modifications to complete */
334 while (atomic_read(&mp->m_active_trans) > 0)
337 /* reclaim inodes to do any IO before the freeze completes */
338 xfs_reclaim_inodes(mp, 0);
339 xfs_reclaim_inodes(mp, SYNC_WAIT);
341 /* flush all pending changes from the AIL */
342 xfs_ail_push_all_sync(mp->m_ail);
345 * Just warn here till VFS can correctly support
346 * read-only remount without racing.
348 WARN_ON(atomic_read(&mp->m_active_trans) != 0);
350 /* Push the superblock and write an unmount record */
351 error = xfs_log_sbcount(mp);
353 xfs_warn(mp, "xfs_attr_quiesce: failed to log sb changes. "
354 "Frozen image may not be consistent.");
355 xfs_log_unmount_write(mp);
358 * At this point we might have modified the superblock again and thus
359 * added an item to the AIL, thus flush it again.
361 xfs_ail_push_all_sync(mp->m_ail);
365 xfs_syncd_queue_sync(
366 struct xfs_mount *mp)
368 queue_delayed_work(xfs_syncd_wq, &mp->m_sync_work,
369 msecs_to_jiffies(xfs_syncd_centisecs * 10));
373 * Every sync period we need to unpin all items, reclaim inodes and sync
374 * disk quotas. We might need to cover the log to indicate that the
375 * filesystem is idle and not frozen.
379 struct work_struct *work)
381 struct xfs_mount *mp = container_of(to_delayed_work(work),
382 struct xfs_mount, m_sync_work);
386 * We shouldn't write/force the log if we are in the mount/unmount
387 * process or on a read only filesystem. The workqueue still needs to be
388 * active in both cases, however, because it is used for inode reclaim
389 * during these times. hence use the MS_ACTIVE flag to avoid doing
390 * anything in these periods.
392 if (!(mp->m_super->s_flags & MS_ACTIVE) &&
393 !(mp->m_flags & XFS_MOUNT_RDONLY)) {
394 /* dgc: errors ignored here */
395 if (mp->m_super->s_frozen == SB_UNFROZEN &&
396 xfs_log_need_covered(mp))
397 error = xfs_fs_log_dummy(mp);
399 xfs_log_force(mp, 0);
401 /* start pushing all the metadata that is currently dirty */
402 xfs_ail_push_all(mp->m_ail);
405 /* queue us up again */
406 xfs_syncd_queue_sync(mp);
410 * Queue a new inode reclaim pass if there are reclaimable inodes and there
411 * isn't a reclaim pass already in progress. By default it runs every 5s based
412 * on the xfs syncd work default of 30s. Perhaps this should have it's own
413 * tunable, but that can be done if this method proves to be ineffective or too
417 xfs_syncd_queue_reclaim(
418 struct xfs_mount *mp)
422 if (radix_tree_tagged(&mp->m_perag_tree, XFS_ICI_RECLAIM_TAG)) {
423 queue_delayed_work(xfs_syncd_wq, &mp->m_reclaim_work,
424 msecs_to_jiffies(xfs_syncd_centisecs / 6 * 10));
430 * This is a fast pass over the inode cache to try to get reclaim moving on as
431 * many inodes as possible in a short period of time. It kicks itself every few
432 * seconds, as well as being kicked by the inode cache shrinker when memory
433 * goes low. It scans as quickly as possible avoiding locked inodes or those
434 * already being flushed, and once done schedules a future pass.
438 struct work_struct *work)
440 struct xfs_mount *mp = container_of(to_delayed_work(work),
441 struct xfs_mount, m_reclaim_work);
443 xfs_reclaim_inodes(mp, SYNC_TRYLOCK);
444 xfs_syncd_queue_reclaim(mp);
448 * Flush delayed allocate data, attempting to free up reserved space
449 * from existing allocations. At this point a new allocation attempt
450 * has failed with ENOSPC and we are in the process of scratching our
451 * heads, looking about for more room.
453 * Queue a new data flush if there isn't one already in progress and
454 * wait for completion of the flush. This means that we only ever have one
455 * inode flush in progress no matter how many ENOSPC events are occurring and
456 * so will prevent the system from bogging down due to every concurrent
457 * ENOSPC event scanning all the active inodes in the system for writeback.
461 struct xfs_inode *ip)
463 struct xfs_mount *mp = ip->i_mount;
465 queue_work(xfs_syncd_wq, &mp->m_flush_work);
466 flush_work_sync(&mp->m_flush_work);
471 struct work_struct *work)
473 struct xfs_mount *mp = container_of(work,
474 struct xfs_mount, m_flush_work);
476 xfs_sync_data(mp, SYNC_TRYLOCK);
477 xfs_sync_data(mp, SYNC_TRYLOCK | SYNC_WAIT);
482 struct xfs_mount *mp)
484 INIT_WORK(&mp->m_flush_work, xfs_flush_worker);
485 INIT_DELAYED_WORK(&mp->m_sync_work, xfs_sync_worker);
486 INIT_DELAYED_WORK(&mp->m_reclaim_work, xfs_reclaim_worker);
488 xfs_syncd_queue_sync(mp);
495 struct xfs_mount *mp)
497 cancel_delayed_work_sync(&mp->m_sync_work);
498 cancel_delayed_work_sync(&mp->m_reclaim_work);
499 cancel_work_sync(&mp->m_flush_work);
503 __xfs_inode_set_reclaim_tag(
504 struct xfs_perag *pag,
505 struct xfs_inode *ip)
507 radix_tree_tag_set(&pag->pag_ici_root,
508 XFS_INO_TO_AGINO(ip->i_mount, ip->i_ino),
509 XFS_ICI_RECLAIM_TAG);
511 if (!pag->pag_ici_reclaimable) {
512 /* propagate the reclaim tag up into the perag radix tree */
513 spin_lock(&ip->i_mount->m_perag_lock);
514 radix_tree_tag_set(&ip->i_mount->m_perag_tree,
515 XFS_INO_TO_AGNO(ip->i_mount, ip->i_ino),
516 XFS_ICI_RECLAIM_TAG);
517 spin_unlock(&ip->i_mount->m_perag_lock);
519 /* schedule periodic background inode reclaim */
520 xfs_syncd_queue_reclaim(ip->i_mount);
522 trace_xfs_perag_set_reclaim(ip->i_mount, pag->pag_agno,
525 pag->pag_ici_reclaimable++;
529 * We set the inode flag atomically with the radix tree tag.
530 * Once we get tag lookups on the radix tree, this inode flag
534 xfs_inode_set_reclaim_tag(
537 struct xfs_mount *mp = ip->i_mount;
538 struct xfs_perag *pag;
540 pag = xfs_perag_get(mp, XFS_INO_TO_AGNO(mp, ip->i_ino));
541 spin_lock(&pag->pag_ici_lock);
542 spin_lock(&ip->i_flags_lock);
543 __xfs_inode_set_reclaim_tag(pag, ip);
544 __xfs_iflags_set(ip, XFS_IRECLAIMABLE);
545 spin_unlock(&ip->i_flags_lock);
546 spin_unlock(&pag->pag_ici_lock);
551 __xfs_inode_clear_reclaim(
555 pag->pag_ici_reclaimable--;
556 if (!pag->pag_ici_reclaimable) {
557 /* clear the reclaim tag from the perag radix tree */
558 spin_lock(&ip->i_mount->m_perag_lock);
559 radix_tree_tag_clear(&ip->i_mount->m_perag_tree,
560 XFS_INO_TO_AGNO(ip->i_mount, ip->i_ino),
561 XFS_ICI_RECLAIM_TAG);
562 spin_unlock(&ip->i_mount->m_perag_lock);
563 trace_xfs_perag_clear_reclaim(ip->i_mount, pag->pag_agno,
569 __xfs_inode_clear_reclaim_tag(
574 radix_tree_tag_clear(&pag->pag_ici_root,
575 XFS_INO_TO_AGINO(mp, ip->i_ino), XFS_ICI_RECLAIM_TAG);
576 __xfs_inode_clear_reclaim(pag, ip);
580 * Grab the inode for reclaim exclusively.
581 * Return 0 if we grabbed it, non-zero otherwise.
584 xfs_reclaim_inode_grab(
585 struct xfs_inode *ip,
588 ASSERT(rcu_read_lock_held());
590 /* quick check for stale RCU freed inode */
595 * If we are asked for non-blocking operation, do unlocked checks to
596 * see if the inode already is being flushed or in reclaim to avoid
599 if ((flags & SYNC_TRYLOCK) &&
600 __xfs_iflags_test(ip, XFS_IFLOCK | XFS_IRECLAIM))
604 * The radix tree lock here protects a thread in xfs_iget from racing
605 * with us starting reclaim on the inode. Once we have the
606 * XFS_IRECLAIM flag set it will not touch us.
608 * Due to RCU lookup, we may find inodes that have been freed and only
609 * have XFS_IRECLAIM set. Indeed, we may see reallocated inodes that
610 * aren't candidates for reclaim at all, so we must check the
611 * XFS_IRECLAIMABLE is set first before proceeding to reclaim.
613 spin_lock(&ip->i_flags_lock);
614 if (!__xfs_iflags_test(ip, XFS_IRECLAIMABLE) ||
615 __xfs_iflags_test(ip, XFS_IRECLAIM)) {
616 /* not a reclaim candidate. */
617 spin_unlock(&ip->i_flags_lock);
620 __xfs_iflags_set(ip, XFS_IRECLAIM);
621 spin_unlock(&ip->i_flags_lock);
626 * Inodes in different states need to be treated differently. The following
627 * table lists the inode states and the reclaim actions necessary:
629 * inode state iflush ret required action
630 * --------------- ---------- ---------------
632 * shutdown EIO unpin and reclaim
633 * clean, unpinned 0 reclaim
634 * stale, unpinned 0 reclaim
635 * clean, pinned(*) 0 requeue
636 * stale, pinned EAGAIN requeue
637 * dirty, async - requeue
638 * dirty, sync 0 reclaim
640 * (*) dgc: I don't think the clean, pinned state is possible but it gets
641 * handled anyway given the order of checks implemented.
643 * Also, because we get the flush lock first, we know that any inode that has
644 * been flushed delwri has had the flush completed by the time we check that
645 * the inode is clean.
647 * Note that because the inode is flushed delayed write by AIL pushing, the
648 * flush lock may already be held here and waiting on it can result in very
649 * long latencies. Hence for sync reclaims, where we wait on the flush lock,
650 * the caller should push the AIL first before trying to reclaim inodes to
651 * minimise the amount of time spent waiting. For background relaim, we only
652 * bother to reclaim clean inodes anyway.
654 * Hence the order of actions after gaining the locks should be:
656 * shutdown => unpin and reclaim
657 * pinned, async => requeue
658 * pinned, sync => unpin
661 * dirty, async => requeue
662 * dirty, sync => flush, wait and reclaim
666 struct xfs_inode *ip,
667 struct xfs_perag *pag,
670 struct xfs_buf *bp = NULL;
675 xfs_ilock(ip, XFS_ILOCK_EXCL);
676 if (!xfs_iflock_nowait(ip)) {
677 if (!(sync_mode & SYNC_WAIT))
682 if (is_bad_inode(VFS_I(ip)))
684 if (XFS_FORCED_SHUTDOWN(ip->i_mount)) {
686 xfs_iflush_abort(ip, false);
689 if (xfs_ipincount(ip)) {
690 if (!(sync_mode & SYNC_WAIT))
694 if (xfs_iflags_test(ip, XFS_ISTALE))
696 if (xfs_inode_clean(ip))
700 * Never flush out dirty data during non-blocking reclaim, as it would
701 * just contend with AIL pushing trying to do the same job.
703 if (!(sync_mode & SYNC_WAIT))
707 * Now we have an inode that needs flushing.
709 * Note that xfs_iflush will never block on the inode buffer lock, as
710 * xfs_ifree_cluster() can lock the inode buffer before it locks the
711 * ip->i_lock, and we are doing the exact opposite here. As a result,
712 * doing a blocking xfs_itobp() to get the cluster buffer would result
713 * in an ABBA deadlock with xfs_ifree_cluster().
715 * As xfs_ifree_cluser() must gather all inodes that are active in the
716 * cache to mark them stale, if we hit this case we don't actually want
717 * to do IO here - we want the inode marked stale so we can simply
718 * reclaim it. Hence if we get an EAGAIN error here, just unlock the
719 * inode, back off and try again. Hopefully the next pass through will
720 * see the stale flag set on the inode.
722 error = xfs_iflush(ip, &bp);
723 if (error == EAGAIN) {
724 xfs_iunlock(ip, XFS_ILOCK_EXCL);
725 /* backoff longer than in xfs_ifree_cluster */
731 error = xfs_bwrite(bp);
738 xfs_iunlock(ip, XFS_ILOCK_EXCL);
740 XFS_STATS_INC(xs_ig_reclaims);
742 * Remove the inode from the per-AG radix tree.
744 * Because radix_tree_delete won't complain even if the item was never
745 * added to the tree assert that it's been there before to catch
746 * problems with the inode life time early on.
748 spin_lock(&pag->pag_ici_lock);
749 if (!radix_tree_delete(&pag->pag_ici_root,
750 XFS_INO_TO_AGINO(ip->i_mount, ip->i_ino)))
752 __xfs_inode_clear_reclaim(pag, ip);
753 spin_unlock(&pag->pag_ici_lock);
756 * Here we do an (almost) spurious inode lock in order to coordinate
757 * with inode cache radix tree lookups. This is because the lookup
758 * can reference the inodes in the cache without taking references.
760 * We make that OK here by ensuring that we wait until the inode is
761 * unlocked after the lookup before we go ahead and free it.
763 xfs_ilock(ip, XFS_ILOCK_EXCL);
765 xfs_iunlock(ip, XFS_ILOCK_EXCL);
773 xfs_iflags_clear(ip, XFS_IRECLAIM);
774 xfs_iunlock(ip, XFS_ILOCK_EXCL);
776 * We could return EAGAIN here to make reclaim rescan the inode tree in
777 * a short while. However, this just burns CPU time scanning the tree
778 * waiting for IO to complete and xfssyncd never goes back to the idle
779 * state. Instead, return 0 to let the next scheduled background reclaim
780 * attempt to reclaim the inode again.
786 * Walk the AGs and reclaim the inodes in them. Even if the filesystem is
787 * corrupted, we still want to try to reclaim all the inodes. If we don't,
788 * then a shut down during filesystem unmount reclaim walk leak all the
789 * unreclaimed inodes.
792 xfs_reclaim_inodes_ag(
793 struct xfs_mount *mp,
797 struct xfs_perag *pag;
801 int trylock = flags & SYNC_TRYLOCK;
807 while ((pag = xfs_perag_get_tag(mp, ag, XFS_ICI_RECLAIM_TAG))) {
808 unsigned long first_index = 0;
812 ag = pag->pag_agno + 1;
815 if (!mutex_trylock(&pag->pag_ici_reclaim_lock)) {
820 first_index = pag->pag_ici_reclaim_cursor;
822 mutex_lock(&pag->pag_ici_reclaim_lock);
825 struct xfs_inode *batch[XFS_LOOKUP_BATCH];
829 nr_found = radix_tree_gang_lookup_tag(
831 (void **)batch, first_index,
833 XFS_ICI_RECLAIM_TAG);
841 * Grab the inodes before we drop the lock. if we found
842 * nothing, nr == 0 and the loop will be skipped.
844 for (i = 0; i < nr_found; i++) {
845 struct xfs_inode *ip = batch[i];
847 if (done || xfs_reclaim_inode_grab(ip, flags))
851 * Update the index for the next lookup. Catch
852 * overflows into the next AG range which can
853 * occur if we have inodes in the last block of
854 * the AG and we are currently pointing to the
857 * Because we may see inodes that are from the
858 * wrong AG due to RCU freeing and
859 * reallocation, only update the index if it
860 * lies in this AG. It was a race that lead us
861 * to see this inode, so another lookup from
862 * the same index will not find it again.
864 if (XFS_INO_TO_AGNO(mp, ip->i_ino) !=
867 first_index = XFS_INO_TO_AGINO(mp, ip->i_ino + 1);
868 if (first_index < XFS_INO_TO_AGINO(mp, ip->i_ino))
872 /* unlock now we've grabbed the inodes. */
875 for (i = 0; i < nr_found; i++) {
878 error = xfs_reclaim_inode(batch[i], pag, flags);
879 if (error && last_error != EFSCORRUPTED)
883 *nr_to_scan -= XFS_LOOKUP_BATCH;
887 } while (nr_found && !done && *nr_to_scan > 0);
889 if (trylock && !done)
890 pag->pag_ici_reclaim_cursor = first_index;
892 pag->pag_ici_reclaim_cursor = 0;
893 mutex_unlock(&pag->pag_ici_reclaim_lock);
898 * if we skipped any AG, and we still have scan count remaining, do
899 * another pass this time using blocking reclaim semantics (i.e
900 * waiting on the reclaim locks and ignoring the reclaim cursors). This
901 * ensure that when we get more reclaimers than AGs we block rather
902 * than spin trying to execute reclaim.
904 if (skipped && (flags & SYNC_WAIT) && *nr_to_scan > 0) {
908 return XFS_ERROR(last_error);
916 int nr_to_scan = INT_MAX;
918 return xfs_reclaim_inodes_ag(mp, mode, &nr_to_scan);
922 * Scan a certain number of inodes for reclaim.
924 * When called we make sure that there is a background (fast) inode reclaim in
925 * progress, while we will throttle the speed of reclaim via doing synchronous
926 * reclaim of inodes. That means if we come across dirty inodes, we wait for
927 * them to be cleaned, which we hope will not be very long due to the
928 * background walker having already kicked the IO off on those dirty inodes.
931 xfs_reclaim_inodes_nr(
932 struct xfs_mount *mp,
935 /* kick background reclaimer and push the AIL */
936 xfs_syncd_queue_reclaim(mp);
937 xfs_ail_push_all(mp->m_ail);
939 xfs_reclaim_inodes_ag(mp, SYNC_TRYLOCK | SYNC_WAIT, &nr_to_scan);
943 * Return the number of reclaimable inodes in the filesystem for
944 * the shrinker to determine how much to reclaim.
947 xfs_reclaim_inodes_count(
948 struct xfs_mount *mp)
950 struct xfs_perag *pag;
951 xfs_agnumber_t ag = 0;
954 while ((pag = xfs_perag_get_tag(mp, ag, XFS_ICI_RECLAIM_TAG))) {
955 ag = pag->pag_agno + 1;
956 reclaimable += pag->pag_ici_reclaimable;