Loading...
Note: File does not exist in v3.1.
1/*
2 * Copyright (c) 2000-2005 Silicon Graphics, Inc.
3 * All Rights Reserved.
4 *
5 * This program is free software; you can redistribute it and/or
6 * modify it under the terms of the GNU General Public License as
7 * published by the Free Software Foundation.
8 *
9 * This program is distributed in the hope that it would be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
13 *
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, write the Free Software Foundation,
16 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
17 */
18#include "xfs.h"
19#include "xfs_fs.h"
20#include "xfs_format.h"
21#include "xfs_log_format.h"
22#include "xfs_trans_resv.h"
23#include "xfs_inum.h"
24#include "xfs_sb.h"
25#include "xfs_ag.h"
26#include "xfs_mount.h"
27#include "xfs_inode.h"
28#include "xfs_error.h"
29#include "xfs_trans.h"
30#include "xfs_trans_priv.h"
31#include "xfs_inode_item.h"
32#include "xfs_quota.h"
33#include "xfs_trace.h"
34#include "xfs_icache.h"
35#include "xfs_bmap_util.h"
36
37#include <linux/kthread.h>
38#include <linux/freezer.h>
39
40STATIC void __xfs_inode_clear_reclaim_tag(struct xfs_mount *mp,
41 struct xfs_perag *pag, struct xfs_inode *ip);
42
43/*
44 * Allocate and initialise an xfs_inode.
45 */
46struct xfs_inode *
47xfs_inode_alloc(
48 struct xfs_mount *mp,
49 xfs_ino_t ino)
50{
51 struct xfs_inode *ip;
52
53 /*
54 * if this didn't occur in transactions, we could use
55 * KM_MAYFAIL and return NULL here on ENOMEM. Set the
56 * code up to do this anyway.
57 */
58 ip = kmem_zone_alloc(xfs_inode_zone, KM_SLEEP);
59 if (!ip)
60 return NULL;
61 if (inode_init_always(mp->m_super, VFS_I(ip))) {
62 kmem_zone_free(xfs_inode_zone, ip);
63 return NULL;
64 }
65
66 ASSERT(atomic_read(&ip->i_pincount) == 0);
67 ASSERT(!spin_is_locked(&ip->i_flags_lock));
68 ASSERT(!xfs_isiflocked(ip));
69 ASSERT(ip->i_ino == 0);
70
71 mrlock_init(&ip->i_iolock, MRLOCK_BARRIER, "xfsio", ip->i_ino);
72
73 /* initialise the xfs inode */
74 ip->i_ino = ino;
75 ip->i_mount = mp;
76 memset(&ip->i_imap, 0, sizeof(struct xfs_imap));
77 ip->i_afp = NULL;
78 memset(&ip->i_df, 0, sizeof(xfs_ifork_t));
79 ip->i_flags = 0;
80 ip->i_delayed_blks = 0;
81 memset(&ip->i_d, 0, sizeof(xfs_icdinode_t));
82
83 return ip;
84}
85
86STATIC void
87xfs_inode_free_callback(
88 struct rcu_head *head)
89{
90 struct inode *inode = container_of(head, struct inode, i_rcu);
91 struct xfs_inode *ip = XFS_I(inode);
92
93 kmem_zone_free(xfs_inode_zone, ip);
94}
95
96void
97xfs_inode_free(
98 struct xfs_inode *ip)
99{
100 switch (ip->i_d.di_mode & S_IFMT) {
101 case S_IFREG:
102 case S_IFDIR:
103 case S_IFLNK:
104 xfs_idestroy_fork(ip, XFS_DATA_FORK);
105 break;
106 }
107
108 if (ip->i_afp)
109 xfs_idestroy_fork(ip, XFS_ATTR_FORK);
110
111 if (ip->i_itemp) {
112 ASSERT(!(ip->i_itemp->ili_item.li_flags & XFS_LI_IN_AIL));
113 xfs_inode_item_destroy(ip);
114 ip->i_itemp = NULL;
115 }
116
117 /*
118 * Because we use RCU freeing we need to ensure the inode always
119 * appears to be reclaimed with an invalid inode number when in the
120 * free state. The ip->i_flags_lock provides the barrier against lookup
121 * races.
122 */
123 spin_lock(&ip->i_flags_lock);
124 ip->i_flags = XFS_IRECLAIM;
125 ip->i_ino = 0;
126 spin_unlock(&ip->i_flags_lock);
127
128 /* asserts to verify all state is correct here */
129 ASSERT(atomic_read(&ip->i_pincount) == 0);
130 ASSERT(!xfs_isiflocked(ip));
131
132 call_rcu(&VFS_I(ip)->i_rcu, xfs_inode_free_callback);
133}
134
135/*
136 * Check the validity of the inode we just found it the cache
137 */
138static int
139xfs_iget_cache_hit(
140 struct xfs_perag *pag,
141 struct xfs_inode *ip,
142 xfs_ino_t ino,
143 int flags,
144 int lock_flags) __releases(RCU)
145{
146 struct inode *inode = VFS_I(ip);
147 struct xfs_mount *mp = ip->i_mount;
148 int error;
149
150 /*
151 * check for re-use of an inode within an RCU grace period due to the
152 * radix tree nodes not being updated yet. We monitor for this by
153 * setting the inode number to zero before freeing the inode structure.
154 * If the inode has been reallocated and set up, then the inode number
155 * will not match, so check for that, too.
156 */
157 spin_lock(&ip->i_flags_lock);
158 if (ip->i_ino != ino) {
159 trace_xfs_iget_skip(ip);
160 XFS_STATS_INC(xs_ig_frecycle);
161 error = EAGAIN;
162 goto out_error;
163 }
164
165
166 /*
167 * If we are racing with another cache hit that is currently
168 * instantiating this inode or currently recycling it out of
169 * reclaimabe state, wait for the initialisation to complete
170 * before continuing.
171 *
172 * XXX(hch): eventually we should do something equivalent to
173 * wait_on_inode to wait for these flags to be cleared
174 * instead of polling for it.
175 */
176 if (ip->i_flags & (XFS_INEW|XFS_IRECLAIM)) {
177 trace_xfs_iget_skip(ip);
178 XFS_STATS_INC(xs_ig_frecycle);
179 error = EAGAIN;
180 goto out_error;
181 }
182
183 /*
184 * If lookup is racing with unlink return an error immediately.
185 */
186 if (ip->i_d.di_mode == 0 && !(flags & XFS_IGET_CREATE)) {
187 error = ENOENT;
188 goto out_error;
189 }
190
191 /*
192 * If IRECLAIMABLE is set, we've torn down the VFS inode already.
193 * Need to carefully get it back into useable state.
194 */
195 if (ip->i_flags & XFS_IRECLAIMABLE) {
196 trace_xfs_iget_reclaim(ip);
197
198 /*
199 * We need to set XFS_IRECLAIM to prevent xfs_reclaim_inode
200 * from stomping over us while we recycle the inode. We can't
201 * clear the radix tree reclaimable tag yet as it requires
202 * pag_ici_lock to be held exclusive.
203 */
204 ip->i_flags |= XFS_IRECLAIM;
205
206 spin_unlock(&ip->i_flags_lock);
207 rcu_read_unlock();
208
209 error = -inode_init_always(mp->m_super, inode);
210 if (error) {
211 /*
212 * Re-initializing the inode failed, and we are in deep
213 * trouble. Try to re-add it to the reclaim list.
214 */
215 rcu_read_lock();
216 spin_lock(&ip->i_flags_lock);
217
218 ip->i_flags &= ~(XFS_INEW | XFS_IRECLAIM);
219 ASSERT(ip->i_flags & XFS_IRECLAIMABLE);
220 trace_xfs_iget_reclaim_fail(ip);
221 goto out_error;
222 }
223
224 spin_lock(&pag->pag_ici_lock);
225 spin_lock(&ip->i_flags_lock);
226
227 /*
228 * Clear the per-lifetime state in the inode as we are now
229 * effectively a new inode and need to return to the initial
230 * state before reuse occurs.
231 */
232 ip->i_flags &= ~XFS_IRECLAIM_RESET_FLAGS;
233 ip->i_flags |= XFS_INEW;
234 __xfs_inode_clear_reclaim_tag(mp, pag, ip);
235 inode->i_state = I_NEW;
236
237 ASSERT(!rwsem_is_locked(&ip->i_iolock.mr_lock));
238 mrlock_init(&ip->i_iolock, MRLOCK_BARRIER, "xfsio", ip->i_ino);
239
240 spin_unlock(&ip->i_flags_lock);
241 spin_unlock(&pag->pag_ici_lock);
242 } else {
243 /* If the VFS inode is being torn down, pause and try again. */
244 if (!igrab(inode)) {
245 trace_xfs_iget_skip(ip);
246 error = EAGAIN;
247 goto out_error;
248 }
249
250 /* We've got a live one. */
251 spin_unlock(&ip->i_flags_lock);
252 rcu_read_unlock();
253 trace_xfs_iget_hit(ip);
254 }
255
256 if (lock_flags != 0)
257 xfs_ilock(ip, lock_flags);
258
259 xfs_iflags_clear(ip, XFS_ISTALE | XFS_IDONTCACHE);
260 XFS_STATS_INC(xs_ig_found);
261
262 return 0;
263
264out_error:
265 spin_unlock(&ip->i_flags_lock);
266 rcu_read_unlock();
267 return error;
268}
269
270
271static int
272xfs_iget_cache_miss(
273 struct xfs_mount *mp,
274 struct xfs_perag *pag,
275 xfs_trans_t *tp,
276 xfs_ino_t ino,
277 struct xfs_inode **ipp,
278 int flags,
279 int lock_flags)
280{
281 struct xfs_inode *ip;
282 int error;
283 xfs_agino_t agino = XFS_INO_TO_AGINO(mp, ino);
284 int iflags;
285
286 ip = xfs_inode_alloc(mp, ino);
287 if (!ip)
288 return ENOMEM;
289
290 error = xfs_iread(mp, tp, ip, flags);
291 if (error)
292 goto out_destroy;
293
294 trace_xfs_iget_miss(ip);
295
296 if ((ip->i_d.di_mode == 0) && !(flags & XFS_IGET_CREATE)) {
297 error = ENOENT;
298 goto out_destroy;
299 }
300
301 /*
302 * Preload the radix tree so we can insert safely under the
303 * write spinlock. Note that we cannot sleep inside the preload
304 * region. Since we can be called from transaction context, don't
305 * recurse into the file system.
306 */
307 if (radix_tree_preload(GFP_NOFS)) {
308 error = EAGAIN;
309 goto out_destroy;
310 }
311
312 /*
313 * Because the inode hasn't been added to the radix-tree yet it can't
314 * be found by another thread, so we can do the non-sleeping lock here.
315 */
316 if (lock_flags) {
317 if (!xfs_ilock_nowait(ip, lock_flags))
318 BUG();
319 }
320
321 /*
322 * These values must be set before inserting the inode into the radix
323 * tree as the moment it is inserted a concurrent lookup (allowed by the
324 * RCU locking mechanism) can find it and that lookup must see that this
325 * is an inode currently under construction (i.e. that XFS_INEW is set).
326 * The ip->i_flags_lock that protects the XFS_INEW flag forms the
327 * memory barrier that ensures this detection works correctly at lookup
328 * time.
329 */
330 iflags = XFS_INEW;
331 if (flags & XFS_IGET_DONTCACHE)
332 iflags |= XFS_IDONTCACHE;
333 ip->i_udquot = NULL;
334 ip->i_gdquot = NULL;
335 ip->i_pdquot = NULL;
336 xfs_iflags_set(ip, iflags);
337
338 /* insert the new inode */
339 spin_lock(&pag->pag_ici_lock);
340 error = radix_tree_insert(&pag->pag_ici_root, agino, ip);
341 if (unlikely(error)) {
342 WARN_ON(error != -EEXIST);
343 XFS_STATS_INC(xs_ig_dup);
344 error = EAGAIN;
345 goto out_preload_end;
346 }
347 spin_unlock(&pag->pag_ici_lock);
348 radix_tree_preload_end();
349
350 *ipp = ip;
351 return 0;
352
353out_preload_end:
354 spin_unlock(&pag->pag_ici_lock);
355 radix_tree_preload_end();
356 if (lock_flags)
357 xfs_iunlock(ip, lock_flags);
358out_destroy:
359 __destroy_inode(VFS_I(ip));
360 xfs_inode_free(ip);
361 return error;
362}
363
364/*
365 * Look up an inode by number in the given file system.
366 * The inode is looked up in the cache held in each AG.
367 * If the inode is found in the cache, initialise the vfs inode
368 * if necessary.
369 *
370 * If it is not in core, read it in from the file system's device,
371 * add it to the cache and initialise the vfs inode.
372 *
373 * The inode is locked according to the value of the lock_flags parameter.
374 * This flag parameter indicates how and if the inode's IO lock and inode lock
375 * should be taken.
376 *
377 * mp -- the mount point structure for the current file system. It points
378 * to the inode hash table.
379 * tp -- a pointer to the current transaction if there is one. This is
380 * simply passed through to the xfs_iread() call.
381 * ino -- the number of the inode desired. This is the unique identifier
382 * within the file system for the inode being requested.
383 * lock_flags -- flags indicating how to lock the inode. See the comment
384 * for xfs_ilock() for a list of valid values.
385 */
386int
387xfs_iget(
388 xfs_mount_t *mp,
389 xfs_trans_t *tp,
390 xfs_ino_t ino,
391 uint flags,
392 uint lock_flags,
393 xfs_inode_t **ipp)
394{
395 xfs_inode_t *ip;
396 int error;
397 xfs_perag_t *pag;
398 xfs_agino_t agino;
399
400 /*
401 * xfs_reclaim_inode() uses the ILOCK to ensure an inode
402 * doesn't get freed while it's being referenced during a
403 * radix tree traversal here. It assumes this function
404 * aqcuires only the ILOCK (and therefore it has no need to
405 * involve the IOLOCK in this synchronization).
406 */
407 ASSERT((lock_flags & (XFS_IOLOCK_EXCL | XFS_IOLOCK_SHARED)) == 0);
408
409 /* reject inode numbers outside existing AGs */
410 if (!ino || XFS_INO_TO_AGNO(mp, ino) >= mp->m_sb.sb_agcount)
411 return EINVAL;
412
413 /* get the perag structure and ensure that it's inode capable */
414 pag = xfs_perag_get(mp, XFS_INO_TO_AGNO(mp, ino));
415 agino = XFS_INO_TO_AGINO(mp, ino);
416
417again:
418 error = 0;
419 rcu_read_lock();
420 ip = radix_tree_lookup(&pag->pag_ici_root, agino);
421
422 if (ip) {
423 error = xfs_iget_cache_hit(pag, ip, ino, flags, lock_flags);
424 if (error)
425 goto out_error_or_again;
426 } else {
427 rcu_read_unlock();
428 XFS_STATS_INC(xs_ig_missed);
429
430 error = xfs_iget_cache_miss(mp, pag, tp, ino, &ip,
431 flags, lock_flags);
432 if (error)
433 goto out_error_or_again;
434 }
435 xfs_perag_put(pag);
436
437 *ipp = ip;
438
439 /*
440 * If we have a real type for an on-disk inode, we can set ops(&unlock)
441 * now. If it's a new inode being created, xfs_ialloc will handle it.
442 */
443 if (xfs_iflags_test(ip, XFS_INEW) && ip->i_d.di_mode != 0)
444 xfs_setup_inode(ip);
445 return 0;
446
447out_error_or_again:
448 if (error == EAGAIN) {
449 delay(1);
450 goto again;
451 }
452 xfs_perag_put(pag);
453 return error;
454}
455
456/*
457 * The inode lookup is done in batches to keep the amount of lock traffic and
458 * radix tree lookups to a minimum. The batch size is a trade off between
459 * lookup reduction and stack usage. This is in the reclaim path, so we can't
460 * be too greedy.
461 */
462#define XFS_LOOKUP_BATCH 32
463
464STATIC int
465xfs_inode_ag_walk_grab(
466 struct xfs_inode *ip)
467{
468 struct inode *inode = VFS_I(ip);
469
470 ASSERT(rcu_read_lock_held());
471
472 /*
473 * check for stale RCU freed inode
474 *
475 * If the inode has been reallocated, it doesn't matter if it's not in
476 * the AG we are walking - we are walking for writeback, so if it
477 * passes all the "valid inode" checks and is dirty, then we'll write
478 * it back anyway. If it has been reallocated and still being
479 * initialised, the XFS_INEW check below will catch it.
480 */
481 spin_lock(&ip->i_flags_lock);
482 if (!ip->i_ino)
483 goto out_unlock_noent;
484
485 /* avoid new or reclaimable inodes. Leave for reclaim code to flush */
486 if (__xfs_iflags_test(ip, XFS_INEW | XFS_IRECLAIMABLE | XFS_IRECLAIM))
487 goto out_unlock_noent;
488 spin_unlock(&ip->i_flags_lock);
489
490 /* nothing to sync during shutdown */
491 if (XFS_FORCED_SHUTDOWN(ip->i_mount))
492 return EFSCORRUPTED;
493
494 /* If we can't grab the inode, it must on it's way to reclaim. */
495 if (!igrab(inode))
496 return ENOENT;
497
498 /* inode is valid */
499 return 0;
500
501out_unlock_noent:
502 spin_unlock(&ip->i_flags_lock);
503 return ENOENT;
504}
505
506STATIC int
507xfs_inode_ag_walk(
508 struct xfs_mount *mp,
509 struct xfs_perag *pag,
510 int (*execute)(struct xfs_inode *ip,
511 struct xfs_perag *pag, int flags,
512 void *args),
513 int flags,
514 void *args,
515 int tag)
516{
517 uint32_t first_index;
518 int last_error = 0;
519 int skipped;
520 int done;
521 int nr_found;
522
523restart:
524 done = 0;
525 skipped = 0;
526 first_index = 0;
527 nr_found = 0;
528 do {
529 struct xfs_inode *batch[XFS_LOOKUP_BATCH];
530 int error = 0;
531 int i;
532
533 rcu_read_lock();
534
535 if (tag == -1)
536 nr_found = radix_tree_gang_lookup(&pag->pag_ici_root,
537 (void **)batch, first_index,
538 XFS_LOOKUP_BATCH);
539 else
540 nr_found = radix_tree_gang_lookup_tag(
541 &pag->pag_ici_root,
542 (void **) batch, first_index,
543 XFS_LOOKUP_BATCH, tag);
544
545 if (!nr_found) {
546 rcu_read_unlock();
547 break;
548 }
549
550 /*
551 * Grab the inodes before we drop the lock. if we found
552 * nothing, nr == 0 and the loop will be skipped.
553 */
554 for (i = 0; i < nr_found; i++) {
555 struct xfs_inode *ip = batch[i];
556
557 if (done || xfs_inode_ag_walk_grab(ip))
558 batch[i] = NULL;
559
560 /*
561 * Update the index for the next lookup. Catch
562 * overflows into the next AG range which can occur if
563 * we have inodes in the last block of the AG and we
564 * are currently pointing to the last inode.
565 *
566 * Because we may see inodes that are from the wrong AG
567 * due to RCU freeing and reallocation, only update the
568 * index if it lies in this AG. It was a race that lead
569 * us to see this inode, so another lookup from the
570 * same index will not find it again.
571 */
572 if (XFS_INO_TO_AGNO(mp, ip->i_ino) != pag->pag_agno)
573 continue;
574 first_index = XFS_INO_TO_AGINO(mp, ip->i_ino + 1);
575 if (first_index < XFS_INO_TO_AGINO(mp, ip->i_ino))
576 done = 1;
577 }
578
579 /* unlock now we've grabbed the inodes. */
580 rcu_read_unlock();
581
582 for (i = 0; i < nr_found; i++) {
583 if (!batch[i])
584 continue;
585 error = execute(batch[i], pag, flags, args);
586 IRELE(batch[i]);
587 if (error == EAGAIN) {
588 skipped++;
589 continue;
590 }
591 if (error && last_error != EFSCORRUPTED)
592 last_error = error;
593 }
594
595 /* bail out if the filesystem is corrupted. */
596 if (error == EFSCORRUPTED)
597 break;
598
599 cond_resched();
600
601 } while (nr_found && !done);
602
603 if (skipped) {
604 delay(1);
605 goto restart;
606 }
607 return last_error;
608}
609
610/*
611 * Background scanning to trim post-EOF preallocated space. This is queued
612 * based on the 'speculative_prealloc_lifetime' tunable (5m by default).
613 */
614STATIC void
615xfs_queue_eofblocks(
616 struct xfs_mount *mp)
617{
618 rcu_read_lock();
619 if (radix_tree_tagged(&mp->m_perag_tree, XFS_ICI_EOFBLOCKS_TAG))
620 queue_delayed_work(mp->m_eofblocks_workqueue,
621 &mp->m_eofblocks_work,
622 msecs_to_jiffies(xfs_eofb_secs * 1000));
623 rcu_read_unlock();
624}
625
626void
627xfs_eofblocks_worker(
628 struct work_struct *work)
629{
630 struct xfs_mount *mp = container_of(to_delayed_work(work),
631 struct xfs_mount, m_eofblocks_work);
632 xfs_icache_free_eofblocks(mp, NULL);
633 xfs_queue_eofblocks(mp);
634}
635
636int
637xfs_inode_ag_iterator(
638 struct xfs_mount *mp,
639 int (*execute)(struct xfs_inode *ip,
640 struct xfs_perag *pag, int flags,
641 void *args),
642 int flags,
643 void *args)
644{
645 struct xfs_perag *pag;
646 int error = 0;
647 int last_error = 0;
648 xfs_agnumber_t ag;
649
650 ag = 0;
651 while ((pag = xfs_perag_get(mp, ag))) {
652 ag = pag->pag_agno + 1;
653 error = xfs_inode_ag_walk(mp, pag, execute, flags, args, -1);
654 xfs_perag_put(pag);
655 if (error) {
656 last_error = error;
657 if (error == EFSCORRUPTED)
658 break;
659 }
660 }
661 return XFS_ERROR(last_error);
662}
663
664int
665xfs_inode_ag_iterator_tag(
666 struct xfs_mount *mp,
667 int (*execute)(struct xfs_inode *ip,
668 struct xfs_perag *pag, int flags,
669 void *args),
670 int flags,
671 void *args,
672 int tag)
673{
674 struct xfs_perag *pag;
675 int error = 0;
676 int last_error = 0;
677 xfs_agnumber_t ag;
678
679 ag = 0;
680 while ((pag = xfs_perag_get_tag(mp, ag, tag))) {
681 ag = pag->pag_agno + 1;
682 error = xfs_inode_ag_walk(mp, pag, execute, flags, args, tag);
683 xfs_perag_put(pag);
684 if (error) {
685 last_error = error;
686 if (error == EFSCORRUPTED)
687 break;
688 }
689 }
690 return XFS_ERROR(last_error);
691}
692
693/*
694 * Queue a new inode reclaim pass if there are reclaimable inodes and there
695 * isn't a reclaim pass already in progress. By default it runs every 5s based
696 * on the xfs periodic sync default of 30s. Perhaps this should have it's own
697 * tunable, but that can be done if this method proves to be ineffective or too
698 * aggressive.
699 */
700static void
701xfs_reclaim_work_queue(
702 struct xfs_mount *mp)
703{
704
705 rcu_read_lock();
706 if (radix_tree_tagged(&mp->m_perag_tree, XFS_ICI_RECLAIM_TAG)) {
707 queue_delayed_work(mp->m_reclaim_workqueue, &mp->m_reclaim_work,
708 msecs_to_jiffies(xfs_syncd_centisecs / 6 * 10));
709 }
710 rcu_read_unlock();
711}
712
713/*
714 * This is a fast pass over the inode cache to try to get reclaim moving on as
715 * many inodes as possible in a short period of time. It kicks itself every few
716 * seconds, as well as being kicked by the inode cache shrinker when memory
717 * goes low. It scans as quickly as possible avoiding locked inodes or those
718 * already being flushed, and once done schedules a future pass.
719 */
720void
721xfs_reclaim_worker(
722 struct work_struct *work)
723{
724 struct xfs_mount *mp = container_of(to_delayed_work(work),
725 struct xfs_mount, m_reclaim_work);
726
727 xfs_reclaim_inodes(mp, SYNC_TRYLOCK);
728 xfs_reclaim_work_queue(mp);
729}
730
731static void
732__xfs_inode_set_reclaim_tag(
733 struct xfs_perag *pag,
734 struct xfs_inode *ip)
735{
736 radix_tree_tag_set(&pag->pag_ici_root,
737 XFS_INO_TO_AGINO(ip->i_mount, ip->i_ino),
738 XFS_ICI_RECLAIM_TAG);
739
740 if (!pag->pag_ici_reclaimable) {
741 /* propagate the reclaim tag up into the perag radix tree */
742 spin_lock(&ip->i_mount->m_perag_lock);
743 radix_tree_tag_set(&ip->i_mount->m_perag_tree,
744 XFS_INO_TO_AGNO(ip->i_mount, ip->i_ino),
745 XFS_ICI_RECLAIM_TAG);
746 spin_unlock(&ip->i_mount->m_perag_lock);
747
748 /* schedule periodic background inode reclaim */
749 xfs_reclaim_work_queue(ip->i_mount);
750
751 trace_xfs_perag_set_reclaim(ip->i_mount, pag->pag_agno,
752 -1, _RET_IP_);
753 }
754 pag->pag_ici_reclaimable++;
755}
756
757/*
758 * We set the inode flag atomically with the radix tree tag.
759 * Once we get tag lookups on the radix tree, this inode flag
760 * can go away.
761 */
762void
763xfs_inode_set_reclaim_tag(
764 xfs_inode_t *ip)
765{
766 struct xfs_mount *mp = ip->i_mount;
767 struct xfs_perag *pag;
768
769 pag = xfs_perag_get(mp, XFS_INO_TO_AGNO(mp, ip->i_ino));
770 spin_lock(&pag->pag_ici_lock);
771 spin_lock(&ip->i_flags_lock);
772 __xfs_inode_set_reclaim_tag(pag, ip);
773 __xfs_iflags_set(ip, XFS_IRECLAIMABLE);
774 spin_unlock(&ip->i_flags_lock);
775 spin_unlock(&pag->pag_ici_lock);
776 xfs_perag_put(pag);
777}
778
779STATIC void
780__xfs_inode_clear_reclaim(
781 xfs_perag_t *pag,
782 xfs_inode_t *ip)
783{
784 pag->pag_ici_reclaimable--;
785 if (!pag->pag_ici_reclaimable) {
786 /* clear the reclaim tag from the perag radix tree */
787 spin_lock(&ip->i_mount->m_perag_lock);
788 radix_tree_tag_clear(&ip->i_mount->m_perag_tree,
789 XFS_INO_TO_AGNO(ip->i_mount, ip->i_ino),
790 XFS_ICI_RECLAIM_TAG);
791 spin_unlock(&ip->i_mount->m_perag_lock);
792 trace_xfs_perag_clear_reclaim(ip->i_mount, pag->pag_agno,
793 -1, _RET_IP_);
794 }
795}
796
797STATIC void
798__xfs_inode_clear_reclaim_tag(
799 xfs_mount_t *mp,
800 xfs_perag_t *pag,
801 xfs_inode_t *ip)
802{
803 radix_tree_tag_clear(&pag->pag_ici_root,
804 XFS_INO_TO_AGINO(mp, ip->i_ino), XFS_ICI_RECLAIM_TAG);
805 __xfs_inode_clear_reclaim(pag, ip);
806}
807
808/*
809 * Grab the inode for reclaim exclusively.
810 * Return 0 if we grabbed it, non-zero otherwise.
811 */
812STATIC int
813xfs_reclaim_inode_grab(
814 struct xfs_inode *ip,
815 int flags)
816{
817 ASSERT(rcu_read_lock_held());
818
819 /* quick check for stale RCU freed inode */
820 if (!ip->i_ino)
821 return 1;
822
823 /*
824 * If we are asked for non-blocking operation, do unlocked checks to
825 * see if the inode already is being flushed or in reclaim to avoid
826 * lock traffic.
827 */
828 if ((flags & SYNC_TRYLOCK) &&
829 __xfs_iflags_test(ip, XFS_IFLOCK | XFS_IRECLAIM))
830 return 1;
831
832 /*
833 * The radix tree lock here protects a thread in xfs_iget from racing
834 * with us starting reclaim on the inode. Once we have the
835 * XFS_IRECLAIM flag set it will not touch us.
836 *
837 * Due to RCU lookup, we may find inodes that have been freed and only
838 * have XFS_IRECLAIM set. Indeed, we may see reallocated inodes that
839 * aren't candidates for reclaim at all, so we must check the
840 * XFS_IRECLAIMABLE is set first before proceeding to reclaim.
841 */
842 spin_lock(&ip->i_flags_lock);
843 if (!__xfs_iflags_test(ip, XFS_IRECLAIMABLE) ||
844 __xfs_iflags_test(ip, XFS_IRECLAIM)) {
845 /* not a reclaim candidate. */
846 spin_unlock(&ip->i_flags_lock);
847 return 1;
848 }
849 __xfs_iflags_set(ip, XFS_IRECLAIM);
850 spin_unlock(&ip->i_flags_lock);
851 return 0;
852}
853
854/*
855 * Inodes in different states need to be treated differently. The following
856 * table lists the inode states and the reclaim actions necessary:
857 *
858 * inode state iflush ret required action
859 * --------------- ---------- ---------------
860 * bad - reclaim
861 * shutdown EIO unpin and reclaim
862 * clean, unpinned 0 reclaim
863 * stale, unpinned 0 reclaim
864 * clean, pinned(*) 0 requeue
865 * stale, pinned EAGAIN requeue
866 * dirty, async - requeue
867 * dirty, sync 0 reclaim
868 *
869 * (*) dgc: I don't think the clean, pinned state is possible but it gets
870 * handled anyway given the order of checks implemented.
871 *
872 * Also, because we get the flush lock first, we know that any inode that has
873 * been flushed delwri has had the flush completed by the time we check that
874 * the inode is clean.
875 *
876 * Note that because the inode is flushed delayed write by AIL pushing, the
877 * flush lock may already be held here and waiting on it can result in very
878 * long latencies. Hence for sync reclaims, where we wait on the flush lock,
879 * the caller should push the AIL first before trying to reclaim inodes to
880 * minimise the amount of time spent waiting. For background relaim, we only
881 * bother to reclaim clean inodes anyway.
882 *
883 * Hence the order of actions after gaining the locks should be:
884 * bad => reclaim
885 * shutdown => unpin and reclaim
886 * pinned, async => requeue
887 * pinned, sync => unpin
888 * stale => reclaim
889 * clean => reclaim
890 * dirty, async => requeue
891 * dirty, sync => flush, wait and reclaim
892 */
893STATIC int
894xfs_reclaim_inode(
895 struct xfs_inode *ip,
896 struct xfs_perag *pag,
897 int sync_mode)
898{
899 struct xfs_buf *bp = NULL;
900 int error;
901
902restart:
903 error = 0;
904 xfs_ilock(ip, XFS_ILOCK_EXCL);
905 if (!xfs_iflock_nowait(ip)) {
906 if (!(sync_mode & SYNC_WAIT))
907 goto out;
908 xfs_iflock(ip);
909 }
910
911 if (XFS_FORCED_SHUTDOWN(ip->i_mount)) {
912 xfs_iunpin_wait(ip);
913 xfs_iflush_abort(ip, false);
914 goto reclaim;
915 }
916 if (xfs_ipincount(ip)) {
917 if (!(sync_mode & SYNC_WAIT))
918 goto out_ifunlock;
919 xfs_iunpin_wait(ip);
920 }
921 if (xfs_iflags_test(ip, XFS_ISTALE))
922 goto reclaim;
923 if (xfs_inode_clean(ip))
924 goto reclaim;
925
926 /*
927 * Never flush out dirty data during non-blocking reclaim, as it would
928 * just contend with AIL pushing trying to do the same job.
929 */
930 if (!(sync_mode & SYNC_WAIT))
931 goto out_ifunlock;
932
933 /*
934 * Now we have an inode that needs flushing.
935 *
936 * Note that xfs_iflush will never block on the inode buffer lock, as
937 * xfs_ifree_cluster() can lock the inode buffer before it locks the
938 * ip->i_lock, and we are doing the exact opposite here. As a result,
939 * doing a blocking xfs_imap_to_bp() to get the cluster buffer would
940 * result in an ABBA deadlock with xfs_ifree_cluster().
941 *
942 * As xfs_ifree_cluser() must gather all inodes that are active in the
943 * cache to mark them stale, if we hit this case we don't actually want
944 * to do IO here - we want the inode marked stale so we can simply
945 * reclaim it. Hence if we get an EAGAIN error here, just unlock the
946 * inode, back off and try again. Hopefully the next pass through will
947 * see the stale flag set on the inode.
948 */
949 error = xfs_iflush(ip, &bp);
950 if (error == EAGAIN) {
951 xfs_iunlock(ip, XFS_ILOCK_EXCL);
952 /* backoff longer than in xfs_ifree_cluster */
953 delay(2);
954 goto restart;
955 }
956
957 if (!error) {
958 error = xfs_bwrite(bp);
959 xfs_buf_relse(bp);
960 }
961
962 xfs_iflock(ip);
963reclaim:
964 xfs_ifunlock(ip);
965 xfs_iunlock(ip, XFS_ILOCK_EXCL);
966
967 XFS_STATS_INC(xs_ig_reclaims);
968 /*
969 * Remove the inode from the per-AG radix tree.
970 *
971 * Because radix_tree_delete won't complain even if the item was never
972 * added to the tree assert that it's been there before to catch
973 * problems with the inode life time early on.
974 */
975 spin_lock(&pag->pag_ici_lock);
976 if (!radix_tree_delete(&pag->pag_ici_root,
977 XFS_INO_TO_AGINO(ip->i_mount, ip->i_ino)))
978 ASSERT(0);
979 __xfs_inode_clear_reclaim(pag, ip);
980 spin_unlock(&pag->pag_ici_lock);
981
982 /*
983 * Here we do an (almost) spurious inode lock in order to coordinate
984 * with inode cache radix tree lookups. This is because the lookup
985 * can reference the inodes in the cache without taking references.
986 *
987 * We make that OK here by ensuring that we wait until the inode is
988 * unlocked after the lookup before we go ahead and free it.
989 */
990 xfs_ilock(ip, XFS_ILOCK_EXCL);
991 xfs_qm_dqdetach(ip);
992 xfs_iunlock(ip, XFS_ILOCK_EXCL);
993
994 xfs_inode_free(ip);
995 return error;
996
997out_ifunlock:
998 xfs_ifunlock(ip);
999out:
1000 xfs_iflags_clear(ip, XFS_IRECLAIM);
1001 xfs_iunlock(ip, XFS_ILOCK_EXCL);
1002 /*
1003 * We could return EAGAIN here to make reclaim rescan the inode tree in
1004 * a short while. However, this just burns CPU time scanning the tree
1005 * waiting for IO to complete and the reclaim work never goes back to
1006 * the idle state. Instead, return 0 to let the next scheduled
1007 * background reclaim attempt to reclaim the inode again.
1008 */
1009 return 0;
1010}
1011
1012/*
1013 * Walk the AGs and reclaim the inodes in them. Even if the filesystem is
1014 * corrupted, we still want to try to reclaim all the inodes. If we don't,
1015 * then a shut down during filesystem unmount reclaim walk leak all the
1016 * unreclaimed inodes.
1017 */
1018STATIC int
1019xfs_reclaim_inodes_ag(
1020 struct xfs_mount *mp,
1021 int flags,
1022 int *nr_to_scan)
1023{
1024 struct xfs_perag *pag;
1025 int error = 0;
1026 int last_error = 0;
1027 xfs_agnumber_t ag;
1028 int trylock = flags & SYNC_TRYLOCK;
1029 int skipped;
1030
1031restart:
1032 ag = 0;
1033 skipped = 0;
1034 while ((pag = xfs_perag_get_tag(mp, ag, XFS_ICI_RECLAIM_TAG))) {
1035 unsigned long first_index = 0;
1036 int done = 0;
1037 int nr_found = 0;
1038
1039 ag = pag->pag_agno + 1;
1040
1041 if (trylock) {
1042 if (!mutex_trylock(&pag->pag_ici_reclaim_lock)) {
1043 skipped++;
1044 xfs_perag_put(pag);
1045 continue;
1046 }
1047 first_index = pag->pag_ici_reclaim_cursor;
1048 } else
1049 mutex_lock(&pag->pag_ici_reclaim_lock);
1050
1051 do {
1052 struct xfs_inode *batch[XFS_LOOKUP_BATCH];
1053 int i;
1054
1055 rcu_read_lock();
1056 nr_found = radix_tree_gang_lookup_tag(
1057 &pag->pag_ici_root,
1058 (void **)batch, first_index,
1059 XFS_LOOKUP_BATCH,
1060 XFS_ICI_RECLAIM_TAG);
1061 if (!nr_found) {
1062 done = 1;
1063 rcu_read_unlock();
1064 break;
1065 }
1066
1067 /*
1068 * Grab the inodes before we drop the lock. if we found
1069 * nothing, nr == 0 and the loop will be skipped.
1070 */
1071 for (i = 0; i < nr_found; i++) {
1072 struct xfs_inode *ip = batch[i];
1073
1074 if (done || xfs_reclaim_inode_grab(ip, flags))
1075 batch[i] = NULL;
1076
1077 /*
1078 * Update the index for the next lookup. Catch
1079 * overflows into the next AG range which can
1080 * occur if we have inodes in the last block of
1081 * the AG and we are currently pointing to the
1082 * last inode.
1083 *
1084 * Because we may see inodes that are from the
1085 * wrong AG due to RCU freeing and
1086 * reallocation, only update the index if it
1087 * lies in this AG. It was a race that lead us
1088 * to see this inode, so another lookup from
1089 * the same index will not find it again.
1090 */
1091 if (XFS_INO_TO_AGNO(mp, ip->i_ino) !=
1092 pag->pag_agno)
1093 continue;
1094 first_index = XFS_INO_TO_AGINO(mp, ip->i_ino + 1);
1095 if (first_index < XFS_INO_TO_AGINO(mp, ip->i_ino))
1096 done = 1;
1097 }
1098
1099 /* unlock now we've grabbed the inodes. */
1100 rcu_read_unlock();
1101
1102 for (i = 0; i < nr_found; i++) {
1103 if (!batch[i])
1104 continue;
1105 error = xfs_reclaim_inode(batch[i], pag, flags);
1106 if (error && last_error != EFSCORRUPTED)
1107 last_error = error;
1108 }
1109
1110 *nr_to_scan -= XFS_LOOKUP_BATCH;
1111
1112 cond_resched();
1113
1114 } while (nr_found && !done && *nr_to_scan > 0);
1115
1116 if (trylock && !done)
1117 pag->pag_ici_reclaim_cursor = first_index;
1118 else
1119 pag->pag_ici_reclaim_cursor = 0;
1120 mutex_unlock(&pag->pag_ici_reclaim_lock);
1121 xfs_perag_put(pag);
1122 }
1123
1124 /*
1125 * if we skipped any AG, and we still have scan count remaining, do
1126 * another pass this time using blocking reclaim semantics (i.e
1127 * waiting on the reclaim locks and ignoring the reclaim cursors). This
1128 * ensure that when we get more reclaimers than AGs we block rather
1129 * than spin trying to execute reclaim.
1130 */
1131 if (skipped && (flags & SYNC_WAIT) && *nr_to_scan > 0) {
1132 trylock = 0;
1133 goto restart;
1134 }
1135 return XFS_ERROR(last_error);
1136}
1137
1138int
1139xfs_reclaim_inodes(
1140 xfs_mount_t *mp,
1141 int mode)
1142{
1143 int nr_to_scan = INT_MAX;
1144
1145 return xfs_reclaim_inodes_ag(mp, mode, &nr_to_scan);
1146}
1147
1148/*
1149 * Scan a certain number of inodes for reclaim.
1150 *
1151 * When called we make sure that there is a background (fast) inode reclaim in
1152 * progress, while we will throttle the speed of reclaim via doing synchronous
1153 * reclaim of inodes. That means if we come across dirty inodes, we wait for
1154 * them to be cleaned, which we hope will not be very long due to the
1155 * background walker having already kicked the IO off on those dirty inodes.
1156 */
1157long
1158xfs_reclaim_inodes_nr(
1159 struct xfs_mount *mp,
1160 int nr_to_scan)
1161{
1162 /* kick background reclaimer and push the AIL */
1163 xfs_reclaim_work_queue(mp);
1164 xfs_ail_push_all(mp->m_ail);
1165
1166 return xfs_reclaim_inodes_ag(mp, SYNC_TRYLOCK | SYNC_WAIT, &nr_to_scan);
1167}
1168
1169/*
1170 * Return the number of reclaimable inodes in the filesystem for
1171 * the shrinker to determine how much to reclaim.
1172 */
1173int
1174xfs_reclaim_inodes_count(
1175 struct xfs_mount *mp)
1176{
1177 struct xfs_perag *pag;
1178 xfs_agnumber_t ag = 0;
1179 int reclaimable = 0;
1180
1181 while ((pag = xfs_perag_get_tag(mp, ag, XFS_ICI_RECLAIM_TAG))) {
1182 ag = pag->pag_agno + 1;
1183 reclaimable += pag->pag_ici_reclaimable;
1184 xfs_perag_put(pag);
1185 }
1186 return reclaimable;
1187}
1188
1189STATIC int
1190xfs_inode_match_id(
1191 struct xfs_inode *ip,
1192 struct xfs_eofblocks *eofb)
1193{
1194 if ((eofb->eof_flags & XFS_EOF_FLAGS_UID) &&
1195 !uid_eq(VFS_I(ip)->i_uid, eofb->eof_uid))
1196 return 0;
1197
1198 if ((eofb->eof_flags & XFS_EOF_FLAGS_GID) &&
1199 !gid_eq(VFS_I(ip)->i_gid, eofb->eof_gid))
1200 return 0;
1201
1202 if ((eofb->eof_flags & XFS_EOF_FLAGS_PRID) &&
1203 xfs_get_projid(ip) != eofb->eof_prid)
1204 return 0;
1205
1206 return 1;
1207}
1208
1209STATIC int
1210xfs_inode_free_eofblocks(
1211 struct xfs_inode *ip,
1212 struct xfs_perag *pag,
1213 int flags,
1214 void *args)
1215{
1216 int ret;
1217 struct xfs_eofblocks *eofb = args;
1218
1219 if (!xfs_can_free_eofblocks(ip, false)) {
1220 /* inode could be preallocated or append-only */
1221 trace_xfs_inode_free_eofblocks_invalid(ip);
1222 xfs_inode_clear_eofblocks_tag(ip);
1223 return 0;
1224 }
1225
1226 /*
1227 * If the mapping is dirty the operation can block and wait for some
1228 * time. Unless we are waiting, skip it.
1229 */
1230 if (!(flags & SYNC_WAIT) &&
1231 mapping_tagged(VFS_I(ip)->i_mapping, PAGECACHE_TAG_DIRTY))
1232 return 0;
1233
1234 if (eofb) {
1235 if (!xfs_inode_match_id(ip, eofb))
1236 return 0;
1237
1238 /* skip the inode if the file size is too small */
1239 if (eofb->eof_flags & XFS_EOF_FLAGS_MINFILESIZE &&
1240 XFS_ISIZE(ip) < eofb->eof_min_file_size)
1241 return 0;
1242 }
1243
1244 ret = xfs_free_eofblocks(ip->i_mount, ip, true);
1245
1246 /* don't revisit the inode if we're not waiting */
1247 if (ret == EAGAIN && !(flags & SYNC_WAIT))
1248 ret = 0;
1249
1250 return ret;
1251}
1252
1253int
1254xfs_icache_free_eofblocks(
1255 struct xfs_mount *mp,
1256 struct xfs_eofblocks *eofb)
1257{
1258 int flags = SYNC_TRYLOCK;
1259
1260 if (eofb && (eofb->eof_flags & XFS_EOF_FLAGS_SYNC))
1261 flags = SYNC_WAIT;
1262
1263 return xfs_inode_ag_iterator_tag(mp, xfs_inode_free_eofblocks, flags,
1264 eofb, XFS_ICI_EOFBLOCKS_TAG);
1265}
1266
1267void
1268xfs_inode_set_eofblocks_tag(
1269 xfs_inode_t *ip)
1270{
1271 struct xfs_mount *mp = ip->i_mount;
1272 struct xfs_perag *pag;
1273 int tagged;
1274
1275 pag = xfs_perag_get(mp, XFS_INO_TO_AGNO(mp, ip->i_ino));
1276 spin_lock(&pag->pag_ici_lock);
1277 trace_xfs_inode_set_eofblocks_tag(ip);
1278
1279 tagged = radix_tree_tagged(&pag->pag_ici_root,
1280 XFS_ICI_EOFBLOCKS_TAG);
1281 radix_tree_tag_set(&pag->pag_ici_root,
1282 XFS_INO_TO_AGINO(ip->i_mount, ip->i_ino),
1283 XFS_ICI_EOFBLOCKS_TAG);
1284 if (!tagged) {
1285 /* propagate the eofblocks tag up into the perag radix tree */
1286 spin_lock(&ip->i_mount->m_perag_lock);
1287 radix_tree_tag_set(&ip->i_mount->m_perag_tree,
1288 XFS_INO_TO_AGNO(ip->i_mount, ip->i_ino),
1289 XFS_ICI_EOFBLOCKS_TAG);
1290 spin_unlock(&ip->i_mount->m_perag_lock);
1291
1292 /* kick off background trimming */
1293 xfs_queue_eofblocks(ip->i_mount);
1294
1295 trace_xfs_perag_set_eofblocks(ip->i_mount, pag->pag_agno,
1296 -1, _RET_IP_);
1297 }
1298
1299 spin_unlock(&pag->pag_ici_lock);
1300 xfs_perag_put(pag);
1301}
1302
1303void
1304xfs_inode_clear_eofblocks_tag(
1305 xfs_inode_t *ip)
1306{
1307 struct xfs_mount *mp = ip->i_mount;
1308 struct xfs_perag *pag;
1309
1310 pag = xfs_perag_get(mp, XFS_INO_TO_AGNO(mp, ip->i_ino));
1311 spin_lock(&pag->pag_ici_lock);
1312 trace_xfs_inode_clear_eofblocks_tag(ip);
1313
1314 radix_tree_tag_clear(&pag->pag_ici_root,
1315 XFS_INO_TO_AGINO(ip->i_mount, ip->i_ino),
1316 XFS_ICI_EOFBLOCKS_TAG);
1317 if (!radix_tree_tagged(&pag->pag_ici_root, XFS_ICI_EOFBLOCKS_TAG)) {
1318 /* clear the eofblocks tag from the perag radix tree */
1319 spin_lock(&ip->i_mount->m_perag_lock);
1320 radix_tree_tag_clear(&ip->i_mount->m_perag_tree,
1321 XFS_INO_TO_AGNO(ip->i_mount, ip->i_ino),
1322 XFS_ICI_EOFBLOCKS_TAG);
1323 spin_unlock(&ip->i_mount->m_perag_lock);
1324 trace_xfs_perag_clear_eofblocks(ip->i_mount, pag->pag_agno,
1325 -1, _RET_IP_);
1326 }
1327
1328 spin_unlock(&pag->pag_ici_lock);
1329 xfs_perag_put(pag);
1330}
1331