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"
22 #include "xfs_log_priv.h"
24 #include "xfs_trans.h"
25 #include "xfs_trans_priv.h"
28 #include "xfs_mount.h"
29 #include "xfs_bmap_btree.h"
30 #include "xfs_inode.h"
31 #include "xfs_dinode.h"
32 #include "xfs_error.h"
33 #include "xfs_filestream.h"
34 #include "xfs_vnodeops.h"
35 #include "xfs_inode_item.h"
36 #include "xfs_quota.h"
37 #include "xfs_trace.h"
38 #include "xfs_fsops.h"
39 #include "xfs_icache.h"
41 #include <linux/kthread.h>
42 #include <linux/freezer.h>
44 STATIC
void __xfs_inode_clear_reclaim_tag(struct xfs_mount
*mp
,
45 struct xfs_perag
*pag
, struct xfs_inode
*ip
);
48 * Allocate and initialise an xfs_inode.
50 STATIC
struct xfs_inode
*
58 * if this didn't occur in transactions, we could use
59 * KM_MAYFAIL and return NULL here on ENOMEM. Set the
60 * code up to do this anyway.
62 ip
= kmem_zone_alloc(xfs_inode_zone
, KM_SLEEP
);
65 if (inode_init_always(mp
->m_super
, VFS_I(ip
))) {
66 kmem_zone_free(xfs_inode_zone
, ip
);
70 ASSERT(atomic_read(&ip
->i_pincount
) == 0);
71 ASSERT(!spin_is_locked(&ip
->i_flags_lock
));
72 ASSERT(!xfs_isiflocked(ip
));
73 ASSERT(ip
->i_ino
== 0);
75 mrlock_init(&ip
->i_iolock
, MRLOCK_BARRIER
, "xfsio", ip
->i_ino
);
77 /* initialise the xfs inode */
80 memset(&ip
->i_imap
, 0, sizeof(struct xfs_imap
));
82 memset(&ip
->i_df
, 0, sizeof(xfs_ifork_t
));
84 ip
->i_delayed_blks
= 0;
85 memset(&ip
->i_d
, 0, sizeof(xfs_icdinode_t
));
91 xfs_inode_free_callback(
92 struct rcu_head
*head
)
94 struct inode
*inode
= container_of(head
, struct inode
, i_rcu
);
95 struct xfs_inode
*ip
= XFS_I(inode
);
97 kmem_zone_free(xfs_inode_zone
, ip
);
102 struct xfs_inode
*ip
)
104 switch (ip
->i_d
.di_mode
& S_IFMT
) {
108 xfs_idestroy_fork(ip
, XFS_DATA_FORK
);
113 xfs_idestroy_fork(ip
, XFS_ATTR_FORK
);
116 ASSERT(!(ip
->i_itemp
->ili_item
.li_flags
& XFS_LI_IN_AIL
));
117 xfs_inode_item_destroy(ip
);
121 /* asserts to verify all state is correct here */
122 ASSERT(atomic_read(&ip
->i_pincount
) == 0);
123 ASSERT(!spin_is_locked(&ip
->i_flags_lock
));
124 ASSERT(!xfs_isiflocked(ip
));
127 * Because we use RCU freeing we need to ensure the inode always
128 * appears to be reclaimed with an invalid inode number when in the
129 * free state. The ip->i_flags_lock provides the barrier against lookup
132 spin_lock(&ip
->i_flags_lock
);
133 ip
->i_flags
= XFS_IRECLAIM
;
135 spin_unlock(&ip
->i_flags_lock
);
137 call_rcu(&VFS_I(ip
)->i_rcu
, xfs_inode_free_callback
);
141 * Check the validity of the inode we just found it the cache
145 struct xfs_perag
*pag
,
146 struct xfs_inode
*ip
,
149 int lock_flags
) __releases(RCU
)
151 struct inode
*inode
= VFS_I(ip
);
152 struct xfs_mount
*mp
= ip
->i_mount
;
156 * check for re-use of an inode within an RCU grace period due to the
157 * radix tree nodes not being updated yet. We monitor for this by
158 * setting the inode number to zero before freeing the inode structure.
159 * If the inode has been reallocated and set up, then the inode number
160 * will not match, so check for that, too.
162 spin_lock(&ip
->i_flags_lock
);
163 if (ip
->i_ino
!= ino
) {
164 trace_xfs_iget_skip(ip
);
165 XFS_STATS_INC(xs_ig_frecycle
);
172 * If we are racing with another cache hit that is currently
173 * instantiating this inode or currently recycling it out of
174 * reclaimabe state, wait for the initialisation to complete
177 * XXX(hch): eventually we should do something equivalent to
178 * wait_on_inode to wait for these flags to be cleared
179 * instead of polling for it.
181 if (ip
->i_flags
& (XFS_INEW
|XFS_IRECLAIM
)) {
182 trace_xfs_iget_skip(ip
);
183 XFS_STATS_INC(xs_ig_frecycle
);
189 * If lookup is racing with unlink return an error immediately.
191 if (ip
->i_d
.di_mode
== 0 && !(flags
& XFS_IGET_CREATE
)) {
197 * If IRECLAIMABLE is set, we've torn down the VFS inode already.
198 * Need to carefully get it back into useable state.
200 if (ip
->i_flags
& XFS_IRECLAIMABLE
) {
201 trace_xfs_iget_reclaim(ip
);
204 * We need to set XFS_IRECLAIM to prevent xfs_reclaim_inode
205 * from stomping over us while we recycle the inode. We can't
206 * clear the radix tree reclaimable tag yet as it requires
207 * pag_ici_lock to be held exclusive.
209 ip
->i_flags
|= XFS_IRECLAIM
;
211 spin_unlock(&ip
->i_flags_lock
);
214 error
= -inode_init_always(mp
->m_super
, inode
);
217 * Re-initializing the inode failed, and we are in deep
218 * trouble. Try to re-add it to the reclaim list.
221 spin_lock(&ip
->i_flags_lock
);
223 ip
->i_flags
&= ~(XFS_INEW
| XFS_IRECLAIM
);
224 ASSERT(ip
->i_flags
& XFS_IRECLAIMABLE
);
225 trace_xfs_iget_reclaim_fail(ip
);
229 spin_lock(&pag
->pag_ici_lock
);
230 spin_lock(&ip
->i_flags_lock
);
233 * Clear the per-lifetime state in the inode as we are now
234 * effectively a new inode and need to return to the initial
235 * state before reuse occurs.
237 ip
->i_flags
&= ~XFS_IRECLAIM_RESET_FLAGS
;
238 ip
->i_flags
|= XFS_INEW
;
239 __xfs_inode_clear_reclaim_tag(mp
, pag
, ip
);
240 inode
->i_state
= I_NEW
;
242 ASSERT(!rwsem_is_locked(&ip
->i_iolock
.mr_lock
));
243 mrlock_init(&ip
->i_iolock
, MRLOCK_BARRIER
, "xfsio", ip
->i_ino
);
245 spin_unlock(&ip
->i_flags_lock
);
246 spin_unlock(&pag
->pag_ici_lock
);
248 /* If the VFS inode is being torn down, pause and try again. */
250 trace_xfs_iget_skip(ip
);
255 /* We've got a live one. */
256 spin_unlock(&ip
->i_flags_lock
);
258 trace_xfs_iget_hit(ip
);
262 xfs_ilock(ip
, lock_flags
);
264 xfs_iflags_clear(ip
, XFS_ISTALE
| XFS_IDONTCACHE
);
265 XFS_STATS_INC(xs_ig_found
);
270 spin_unlock(&ip
->i_flags_lock
);
278 struct xfs_mount
*mp
,
279 struct xfs_perag
*pag
,
282 struct xfs_inode
**ipp
,
286 struct xfs_inode
*ip
;
288 xfs_agino_t agino
= XFS_INO_TO_AGINO(mp
, ino
);
291 ip
= xfs_inode_alloc(mp
, ino
);
295 error
= xfs_iread(mp
, tp
, ip
, flags
);
299 trace_xfs_iget_miss(ip
);
301 if ((ip
->i_d
.di_mode
== 0) && !(flags
& XFS_IGET_CREATE
)) {
307 * Preload the radix tree so we can insert safely under the
308 * write spinlock. Note that we cannot sleep inside the preload
309 * region. Since we can be called from transaction context, don't
310 * recurse into the file system.
312 if (radix_tree_preload(GFP_NOFS
)) {
318 * Because the inode hasn't been added to the radix-tree yet it can't
319 * be found by another thread, so we can do the non-sleeping lock here.
322 if (!xfs_ilock_nowait(ip
, lock_flags
))
327 * These values must be set before inserting the inode into the radix
328 * tree as the moment it is inserted a concurrent lookup (allowed by the
329 * RCU locking mechanism) can find it and that lookup must see that this
330 * is an inode currently under construction (i.e. that XFS_INEW is set).
331 * The ip->i_flags_lock that protects the XFS_INEW flag forms the
332 * memory barrier that ensures this detection works correctly at lookup
336 if (flags
& XFS_IGET_DONTCACHE
)
337 iflags
|= XFS_IDONTCACHE
;
338 ip
->i_udquot
= ip
->i_gdquot
= NULL
;
339 xfs_iflags_set(ip
, iflags
);
341 /* insert the new inode */
342 spin_lock(&pag
->pag_ici_lock
);
343 error
= radix_tree_insert(&pag
->pag_ici_root
, agino
, ip
);
344 if (unlikely(error
)) {
345 WARN_ON(error
!= -EEXIST
);
346 XFS_STATS_INC(xs_ig_dup
);
348 goto out_preload_end
;
350 spin_unlock(&pag
->pag_ici_lock
);
351 radix_tree_preload_end();
357 spin_unlock(&pag
->pag_ici_lock
);
358 radix_tree_preload_end();
360 xfs_iunlock(ip
, lock_flags
);
362 __destroy_inode(VFS_I(ip
));
368 * Look up an inode by number in the given file system.
369 * The inode is looked up in the cache held in each AG.
370 * If the inode is found in the cache, initialise the vfs inode
373 * If it is not in core, read it in from the file system's device,
374 * add it to the cache and initialise the vfs inode.
376 * The inode is locked according to the value of the lock_flags parameter.
377 * This flag parameter indicates how and if the inode's IO lock and inode lock
380 * mp -- the mount point structure for the current file system. It points
381 * to the inode hash table.
382 * tp -- a pointer to the current transaction if there is one. This is
383 * simply passed through to the xfs_iread() call.
384 * ino -- the number of the inode desired. This is the unique identifier
385 * within the file system for the inode being requested.
386 * lock_flags -- flags indicating how to lock the inode. See the comment
387 * for xfs_ilock() for a list of valid values.
404 * xfs_reclaim_inode() uses the ILOCK to ensure an inode
405 * doesn't get freed while it's being referenced during a
406 * radix tree traversal here. It assumes this function
407 * aqcuires only the ILOCK (and therefore it has no need to
408 * involve the IOLOCK in this synchronization).
410 ASSERT((lock_flags
& (XFS_IOLOCK_EXCL
| XFS_IOLOCK_SHARED
)) == 0);
412 /* reject inode numbers outside existing AGs */
413 if (!ino
|| XFS_INO_TO_AGNO(mp
, ino
) >= mp
->m_sb
.sb_agcount
)
416 /* get the perag structure and ensure that it's inode capable */
417 pag
= xfs_perag_get(mp
, XFS_INO_TO_AGNO(mp
, ino
));
418 agino
= XFS_INO_TO_AGINO(mp
, ino
);
423 ip
= radix_tree_lookup(&pag
->pag_ici_root
, agino
);
426 error
= xfs_iget_cache_hit(pag
, ip
, ino
, flags
, lock_flags
);
428 goto out_error_or_again
;
431 XFS_STATS_INC(xs_ig_missed
);
433 error
= xfs_iget_cache_miss(mp
, pag
, tp
, ino
, &ip
,
436 goto out_error_or_again
;
443 * If we have a real type for an on-disk inode, we can set ops(&unlock)
444 * now. If it's a new inode being created, xfs_ialloc will handle it.
446 if (xfs_iflags_test(ip
, XFS_INEW
) && ip
->i_d
.di_mode
!= 0)
451 if (error
== EAGAIN
) {
460 * The inode lookup is done in batches to keep the amount of lock traffic and
461 * radix tree lookups to a minimum. The batch size is a trade off between
462 * lookup reduction and stack usage. This is in the reclaim path, so we can't
465 #define XFS_LOOKUP_BATCH 32
468 xfs_inode_ag_walk_grab(
469 struct xfs_inode
*ip
)
471 struct inode
*inode
= VFS_I(ip
);
473 ASSERT(rcu_read_lock_held());
476 * check for stale RCU freed inode
478 * If the inode has been reallocated, it doesn't matter if it's not in
479 * the AG we are walking - we are walking for writeback, so if it
480 * passes all the "valid inode" checks and is dirty, then we'll write
481 * it back anyway. If it has been reallocated and still being
482 * initialised, the XFS_INEW check below will catch it.
484 spin_lock(&ip
->i_flags_lock
);
486 goto out_unlock_noent
;
488 /* avoid new or reclaimable inodes. Leave for reclaim code to flush */
489 if (__xfs_iflags_test(ip
, XFS_INEW
| XFS_IRECLAIMABLE
| XFS_IRECLAIM
))
490 goto out_unlock_noent
;
491 spin_unlock(&ip
->i_flags_lock
);
493 /* nothing to sync during shutdown */
494 if (XFS_FORCED_SHUTDOWN(ip
->i_mount
))
497 /* If we can't grab the inode, it must on it's way to reclaim. */
501 if (is_bad_inode(inode
)) {
510 spin_unlock(&ip
->i_flags_lock
);
516 struct xfs_mount
*mp
,
517 struct xfs_perag
*pag
,
518 int (*execute
)(struct xfs_inode
*ip
,
519 struct xfs_perag
*pag
, int flags
),
522 uint32_t first_index
;
534 struct xfs_inode
*batch
[XFS_LOOKUP_BATCH
];
539 nr_found
= radix_tree_gang_lookup(&pag
->pag_ici_root
,
540 (void **)batch
, first_index
,
548 * Grab the inodes before we drop the lock. if we found
549 * nothing, nr == 0 and the loop will be skipped.
551 for (i
= 0; i
< nr_found
; i
++) {
552 struct xfs_inode
*ip
= batch
[i
];
554 if (done
|| xfs_inode_ag_walk_grab(ip
))
558 * Update the index for the next lookup. Catch
559 * overflows into the next AG range which can occur if
560 * we have inodes in the last block of the AG and we
561 * are currently pointing to the last inode.
563 * Because we may see inodes that are from the wrong AG
564 * due to RCU freeing and reallocation, only update the
565 * index if it lies in this AG. It was a race that lead
566 * us to see this inode, so another lookup from the
567 * same index will not find it again.
569 if (XFS_INO_TO_AGNO(mp
, ip
->i_ino
) != pag
->pag_agno
)
571 first_index
= XFS_INO_TO_AGINO(mp
, ip
->i_ino
+ 1);
572 if (first_index
< XFS_INO_TO_AGINO(mp
, ip
->i_ino
))
576 /* unlock now we've grabbed the inodes. */
579 for (i
= 0; i
< nr_found
; i
++) {
582 error
= execute(batch
[i
], pag
, flags
);
584 if (error
== EAGAIN
) {
588 if (error
&& last_error
!= EFSCORRUPTED
)
592 /* bail out if the filesystem is corrupted. */
593 if (error
== EFSCORRUPTED
)
598 } while (nr_found
&& !done
);
608 xfs_inode_ag_iterator(
609 struct xfs_mount
*mp
,
610 int (*execute
)(struct xfs_inode
*ip
,
611 struct xfs_perag
*pag
, int flags
),
614 struct xfs_perag
*pag
;
620 while ((pag
= xfs_perag_get(mp
, ag
))) {
621 ag
= pag
->pag_agno
+ 1;
622 error
= xfs_inode_ag_walk(mp
, pag
, execute
, flags
);
626 if (error
== EFSCORRUPTED
)
630 return XFS_ERROR(last_error
);
634 * Queue a new inode reclaim pass if there are reclaimable inodes and there
635 * isn't a reclaim pass already in progress. By default it runs every 5s based
636 * on the xfs periodic sync default of 30s. Perhaps this should have it's own
637 * tunable, but that can be done if this method proves to be ineffective or too
641 xfs_reclaim_work_queue(
642 struct xfs_mount
*mp
)
646 if (radix_tree_tagged(&mp
->m_perag_tree
, XFS_ICI_RECLAIM_TAG
)) {
647 queue_delayed_work(mp
->m_reclaim_workqueue
, &mp
->m_reclaim_work
,
648 msecs_to_jiffies(xfs_syncd_centisecs
/ 6 * 10));
654 * This is a fast pass over the inode cache to try to get reclaim moving on as
655 * many inodes as possible in a short period of time. It kicks itself every few
656 * seconds, as well as being kicked by the inode cache shrinker when memory
657 * goes low. It scans as quickly as possible avoiding locked inodes or those
658 * already being flushed, and once done schedules a future pass.
662 struct work_struct
*work
)
664 struct xfs_mount
*mp
= container_of(to_delayed_work(work
),
665 struct xfs_mount
, m_reclaim_work
);
667 xfs_reclaim_inodes(mp
, SYNC_TRYLOCK
);
668 xfs_reclaim_work_queue(mp
);
672 __xfs_inode_set_reclaim_tag(
673 struct xfs_perag
*pag
,
674 struct xfs_inode
*ip
)
676 radix_tree_tag_set(&pag
->pag_ici_root
,
677 XFS_INO_TO_AGINO(ip
->i_mount
, ip
->i_ino
),
678 XFS_ICI_RECLAIM_TAG
);
680 if (!pag
->pag_ici_reclaimable
) {
681 /* propagate the reclaim tag up into the perag radix tree */
682 spin_lock(&ip
->i_mount
->m_perag_lock
);
683 radix_tree_tag_set(&ip
->i_mount
->m_perag_tree
,
684 XFS_INO_TO_AGNO(ip
->i_mount
, ip
->i_ino
),
685 XFS_ICI_RECLAIM_TAG
);
686 spin_unlock(&ip
->i_mount
->m_perag_lock
);
688 /* schedule periodic background inode reclaim */
689 xfs_reclaim_work_queue(ip
->i_mount
);
691 trace_xfs_perag_set_reclaim(ip
->i_mount
, pag
->pag_agno
,
694 pag
->pag_ici_reclaimable
++;
698 * We set the inode flag atomically with the radix tree tag.
699 * Once we get tag lookups on the radix tree, this inode flag
703 xfs_inode_set_reclaim_tag(
706 struct xfs_mount
*mp
= ip
->i_mount
;
707 struct xfs_perag
*pag
;
709 pag
= xfs_perag_get(mp
, XFS_INO_TO_AGNO(mp
, ip
->i_ino
));
710 spin_lock(&pag
->pag_ici_lock
);
711 spin_lock(&ip
->i_flags_lock
);
712 __xfs_inode_set_reclaim_tag(pag
, ip
);
713 __xfs_iflags_set(ip
, XFS_IRECLAIMABLE
);
714 spin_unlock(&ip
->i_flags_lock
);
715 spin_unlock(&pag
->pag_ici_lock
);
720 __xfs_inode_clear_reclaim(
724 pag
->pag_ici_reclaimable
--;
725 if (!pag
->pag_ici_reclaimable
) {
726 /* clear the reclaim tag from the perag radix tree */
727 spin_lock(&ip
->i_mount
->m_perag_lock
);
728 radix_tree_tag_clear(&ip
->i_mount
->m_perag_tree
,
729 XFS_INO_TO_AGNO(ip
->i_mount
, ip
->i_ino
),
730 XFS_ICI_RECLAIM_TAG
);
731 spin_unlock(&ip
->i_mount
->m_perag_lock
);
732 trace_xfs_perag_clear_reclaim(ip
->i_mount
, pag
->pag_agno
,
738 __xfs_inode_clear_reclaim_tag(
743 radix_tree_tag_clear(&pag
->pag_ici_root
,
744 XFS_INO_TO_AGINO(mp
, ip
->i_ino
), XFS_ICI_RECLAIM_TAG
);
745 __xfs_inode_clear_reclaim(pag
, ip
);
749 * Grab the inode for reclaim exclusively.
750 * Return 0 if we grabbed it, non-zero otherwise.
753 xfs_reclaim_inode_grab(
754 struct xfs_inode
*ip
,
757 ASSERT(rcu_read_lock_held());
759 /* quick check for stale RCU freed inode */
764 * If we are asked for non-blocking operation, do unlocked checks to
765 * see if the inode already is being flushed or in reclaim to avoid
768 if ((flags
& SYNC_TRYLOCK
) &&
769 __xfs_iflags_test(ip
, XFS_IFLOCK
| XFS_IRECLAIM
))
773 * The radix tree lock here protects a thread in xfs_iget from racing
774 * with us starting reclaim on the inode. Once we have the
775 * XFS_IRECLAIM flag set it will not touch us.
777 * Due to RCU lookup, we may find inodes that have been freed and only
778 * have XFS_IRECLAIM set. Indeed, we may see reallocated inodes that
779 * aren't candidates for reclaim at all, so we must check the
780 * XFS_IRECLAIMABLE is set first before proceeding to reclaim.
782 spin_lock(&ip
->i_flags_lock
);
783 if (!__xfs_iflags_test(ip
, XFS_IRECLAIMABLE
) ||
784 __xfs_iflags_test(ip
, XFS_IRECLAIM
)) {
785 /* not a reclaim candidate. */
786 spin_unlock(&ip
->i_flags_lock
);
789 __xfs_iflags_set(ip
, XFS_IRECLAIM
);
790 spin_unlock(&ip
->i_flags_lock
);
795 * Inodes in different states need to be treated differently. The following
796 * table lists the inode states and the reclaim actions necessary:
798 * inode state iflush ret required action
799 * --------------- ---------- ---------------
801 * shutdown EIO unpin and reclaim
802 * clean, unpinned 0 reclaim
803 * stale, unpinned 0 reclaim
804 * clean, pinned(*) 0 requeue
805 * stale, pinned EAGAIN requeue
806 * dirty, async - requeue
807 * dirty, sync 0 reclaim
809 * (*) dgc: I don't think the clean, pinned state is possible but it gets
810 * handled anyway given the order of checks implemented.
812 * Also, because we get the flush lock first, we know that any inode that has
813 * been flushed delwri has had the flush completed by the time we check that
814 * the inode is clean.
816 * Note that because the inode is flushed delayed write by AIL pushing, the
817 * flush lock may already be held here and waiting on it can result in very
818 * long latencies. Hence for sync reclaims, where we wait on the flush lock,
819 * the caller should push the AIL first before trying to reclaim inodes to
820 * minimise the amount of time spent waiting. For background relaim, we only
821 * bother to reclaim clean inodes anyway.
823 * Hence the order of actions after gaining the locks should be:
825 * shutdown => unpin and reclaim
826 * pinned, async => requeue
827 * pinned, sync => unpin
830 * dirty, async => requeue
831 * dirty, sync => flush, wait and reclaim
835 struct xfs_inode
*ip
,
836 struct xfs_perag
*pag
,
839 struct xfs_buf
*bp
= NULL
;
844 xfs_ilock(ip
, XFS_ILOCK_EXCL
);
845 if (!xfs_iflock_nowait(ip
)) {
846 if (!(sync_mode
& SYNC_WAIT
))
851 if (is_bad_inode(VFS_I(ip
)))
853 if (XFS_FORCED_SHUTDOWN(ip
->i_mount
)) {
855 xfs_iflush_abort(ip
, false);
858 if (xfs_ipincount(ip
)) {
859 if (!(sync_mode
& SYNC_WAIT
))
863 if (xfs_iflags_test(ip
, XFS_ISTALE
))
865 if (xfs_inode_clean(ip
))
869 * Never flush out dirty data during non-blocking reclaim, as it would
870 * just contend with AIL pushing trying to do the same job.
872 if (!(sync_mode
& SYNC_WAIT
))
876 * Now we have an inode that needs flushing.
878 * Note that xfs_iflush will never block on the inode buffer lock, as
879 * xfs_ifree_cluster() can lock the inode buffer before it locks the
880 * ip->i_lock, and we are doing the exact opposite here. As a result,
881 * doing a blocking xfs_imap_to_bp() to get the cluster buffer would
882 * result in an ABBA deadlock with xfs_ifree_cluster().
884 * As xfs_ifree_cluser() must gather all inodes that are active in the
885 * cache to mark them stale, if we hit this case we don't actually want
886 * to do IO here - we want the inode marked stale so we can simply
887 * reclaim it. Hence if we get an EAGAIN error here, just unlock the
888 * inode, back off and try again. Hopefully the next pass through will
889 * see the stale flag set on the inode.
891 error
= xfs_iflush(ip
, &bp
);
892 if (error
== EAGAIN
) {
893 xfs_iunlock(ip
, XFS_ILOCK_EXCL
);
894 /* backoff longer than in xfs_ifree_cluster */
900 error
= xfs_bwrite(bp
);
907 xfs_iunlock(ip
, XFS_ILOCK_EXCL
);
909 XFS_STATS_INC(xs_ig_reclaims
);
911 * Remove the inode from the per-AG radix tree.
913 * Because radix_tree_delete won't complain even if the item was never
914 * added to the tree assert that it's been there before to catch
915 * problems with the inode life time early on.
917 spin_lock(&pag
->pag_ici_lock
);
918 if (!radix_tree_delete(&pag
->pag_ici_root
,
919 XFS_INO_TO_AGINO(ip
->i_mount
, ip
->i_ino
)))
921 __xfs_inode_clear_reclaim(pag
, ip
);
922 spin_unlock(&pag
->pag_ici_lock
);
925 * Here we do an (almost) spurious inode lock in order to coordinate
926 * with inode cache radix tree lookups. This is because the lookup
927 * can reference the inodes in the cache without taking references.
929 * We make that OK here by ensuring that we wait until the inode is
930 * unlocked after the lookup before we go ahead and free it.
932 xfs_ilock(ip
, XFS_ILOCK_EXCL
);
934 xfs_iunlock(ip
, XFS_ILOCK_EXCL
);
942 xfs_iflags_clear(ip
, XFS_IRECLAIM
);
943 xfs_iunlock(ip
, XFS_ILOCK_EXCL
);
945 * We could return EAGAIN here to make reclaim rescan the inode tree in
946 * a short while. However, this just burns CPU time scanning the tree
947 * waiting for IO to complete and the reclaim work never goes back to
948 * the idle state. Instead, return 0 to let the next scheduled
949 * background reclaim attempt to reclaim the inode again.
955 * Walk the AGs and reclaim the inodes in them. Even if the filesystem is
956 * corrupted, we still want to try to reclaim all the inodes. If we don't,
957 * then a shut down during filesystem unmount reclaim walk leak all the
958 * unreclaimed inodes.
961 xfs_reclaim_inodes_ag(
962 struct xfs_mount
*mp
,
966 struct xfs_perag
*pag
;
970 int trylock
= flags
& SYNC_TRYLOCK
;
976 while ((pag
= xfs_perag_get_tag(mp
, ag
, XFS_ICI_RECLAIM_TAG
))) {
977 unsigned long first_index
= 0;
981 ag
= pag
->pag_agno
+ 1;
984 if (!mutex_trylock(&pag
->pag_ici_reclaim_lock
)) {
989 first_index
= pag
->pag_ici_reclaim_cursor
;
991 mutex_lock(&pag
->pag_ici_reclaim_lock
);
994 struct xfs_inode
*batch
[XFS_LOOKUP_BATCH
];
998 nr_found
= radix_tree_gang_lookup_tag(
1000 (void **)batch
, first_index
,
1002 XFS_ICI_RECLAIM_TAG
);
1010 * Grab the inodes before we drop the lock. if we found
1011 * nothing, nr == 0 and the loop will be skipped.
1013 for (i
= 0; i
< nr_found
; i
++) {
1014 struct xfs_inode
*ip
= batch
[i
];
1016 if (done
|| xfs_reclaim_inode_grab(ip
, flags
))
1020 * Update the index for the next lookup. Catch
1021 * overflows into the next AG range which can
1022 * occur if we have inodes in the last block of
1023 * the AG and we are currently pointing to the
1026 * Because we may see inodes that are from the
1027 * wrong AG due to RCU freeing and
1028 * reallocation, only update the index if it
1029 * lies in this AG. It was a race that lead us
1030 * to see this inode, so another lookup from
1031 * the same index will not find it again.
1033 if (XFS_INO_TO_AGNO(mp
, ip
->i_ino
) !=
1036 first_index
= XFS_INO_TO_AGINO(mp
, ip
->i_ino
+ 1);
1037 if (first_index
< XFS_INO_TO_AGINO(mp
, ip
->i_ino
))
1041 /* unlock now we've grabbed the inodes. */
1044 for (i
= 0; i
< nr_found
; i
++) {
1047 error
= xfs_reclaim_inode(batch
[i
], pag
, flags
);
1048 if (error
&& last_error
!= EFSCORRUPTED
)
1052 *nr_to_scan
-= XFS_LOOKUP_BATCH
;
1056 } while (nr_found
&& !done
&& *nr_to_scan
> 0);
1058 if (trylock
&& !done
)
1059 pag
->pag_ici_reclaim_cursor
= first_index
;
1061 pag
->pag_ici_reclaim_cursor
= 0;
1062 mutex_unlock(&pag
->pag_ici_reclaim_lock
);
1067 * if we skipped any AG, and we still have scan count remaining, do
1068 * another pass this time using blocking reclaim semantics (i.e
1069 * waiting on the reclaim locks and ignoring the reclaim cursors). This
1070 * ensure that when we get more reclaimers than AGs we block rather
1071 * than spin trying to execute reclaim.
1073 if (skipped
&& (flags
& SYNC_WAIT
) && *nr_to_scan
> 0) {
1077 return XFS_ERROR(last_error
);
1085 int nr_to_scan
= INT_MAX
;
1087 return xfs_reclaim_inodes_ag(mp
, mode
, &nr_to_scan
);
1091 * Scan a certain number of inodes for reclaim.
1093 * When called we make sure that there is a background (fast) inode reclaim in
1094 * progress, while we will throttle the speed of reclaim via doing synchronous
1095 * reclaim of inodes. That means if we come across dirty inodes, we wait for
1096 * them to be cleaned, which we hope will not be very long due to the
1097 * background walker having already kicked the IO off on those dirty inodes.
1100 xfs_reclaim_inodes_nr(
1101 struct xfs_mount
*mp
,
1104 /* kick background reclaimer and push the AIL */
1105 xfs_reclaim_work_queue(mp
);
1106 xfs_ail_push_all(mp
->m_ail
);
1108 xfs_reclaim_inodes_ag(mp
, SYNC_TRYLOCK
| SYNC_WAIT
, &nr_to_scan
);
1112 * Return the number of reclaimable inodes in the filesystem for
1113 * the shrinker to determine how much to reclaim.
1116 xfs_reclaim_inodes_count(
1117 struct xfs_mount
*mp
)
1119 struct xfs_perag
*pag
;
1120 xfs_agnumber_t ag
= 0;
1121 int reclaimable
= 0;
1123 while ((pag
= xfs_perag_get_tag(mp
, ag
, XFS_ICI_RECLAIM_TAG
))) {
1124 ag
= pag
->pag_agno
+ 1;
1125 reclaimable
+= pag
->pag_ici_reclaimable
;
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