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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_sb.h"
13#include "xfs_mount.h"
14#include "xfs_inode.h"
15#include "xfs_trans.h"
16#include "xfs_trans_priv.h"
17#include "xfs_inode_item.h"
18#include "xfs_quota.h"
19#include "xfs_trace.h"
20#include "xfs_icache.h"
21#include "xfs_bmap_util.h"
22#include "xfs_dquot_item.h"
23#include "xfs_dquot.h"
24#include "xfs_reflink.h"
25
26#include <linux/iversion.h>
27
28/*
29 * Allocate and initialise an xfs_inode.
30 */
31struct xfs_inode *
32xfs_inode_alloc(
33 struct xfs_mount *mp,
34 xfs_ino_t ino)
35{
36 struct xfs_inode *ip;
37
38 /*
39 * if this didn't occur in transactions, we could use
40 * KM_MAYFAIL and return NULL here on ENOMEM. Set the
41 * code up to do this anyway.
42 */
43 ip = kmem_zone_alloc(xfs_inode_zone, 0);
44 if (!ip)
45 return NULL;
46 if (inode_init_always(mp->m_super, VFS_I(ip))) {
47 kmem_zone_free(xfs_inode_zone, ip);
48 return NULL;
49 }
50
51 /* VFS doesn't initialise i_mode! */
52 VFS_I(ip)->i_mode = 0;
53
54 XFS_STATS_INC(mp, vn_active);
55 ASSERT(atomic_read(&ip->i_pincount) == 0);
56 ASSERT(!xfs_isiflocked(ip));
57 ASSERT(ip->i_ino == 0);
58
59 /* initialise the xfs inode */
60 ip->i_ino = ino;
61 ip->i_mount = mp;
62 memset(&ip->i_imap, 0, sizeof(struct xfs_imap));
63 ip->i_afp = NULL;
64 ip->i_cowfp = NULL;
65 ip->i_cnextents = 0;
66 ip->i_cformat = XFS_DINODE_FMT_EXTENTS;
67 memset(&ip->i_df, 0, sizeof(ip->i_df));
68 ip->i_flags = 0;
69 ip->i_delayed_blks = 0;
70 memset(&ip->i_d, 0, sizeof(ip->i_d));
71 ip->i_sick = 0;
72 ip->i_checked = 0;
73 INIT_WORK(&ip->i_ioend_work, xfs_end_io);
74 INIT_LIST_HEAD(&ip->i_ioend_list);
75 spin_lock_init(&ip->i_ioend_lock);
76
77 return ip;
78}
79
80STATIC void
81xfs_inode_free_callback(
82 struct rcu_head *head)
83{
84 struct inode *inode = container_of(head, struct inode, i_rcu);
85 struct xfs_inode *ip = XFS_I(inode);
86
87 switch (VFS_I(ip)->i_mode & S_IFMT) {
88 case S_IFREG:
89 case S_IFDIR:
90 case S_IFLNK:
91 xfs_idestroy_fork(ip, XFS_DATA_FORK);
92 break;
93 }
94
95 if (ip->i_afp)
96 xfs_idestroy_fork(ip, XFS_ATTR_FORK);
97 if (ip->i_cowfp)
98 xfs_idestroy_fork(ip, XFS_COW_FORK);
99
100 if (ip->i_itemp) {
101 ASSERT(!test_bit(XFS_LI_IN_AIL,
102 &ip->i_itemp->ili_item.li_flags));
103 xfs_inode_item_destroy(ip);
104 ip->i_itemp = NULL;
105 }
106
107 kmem_zone_free(xfs_inode_zone, ip);
108}
109
110static void
111__xfs_inode_free(
112 struct xfs_inode *ip)
113{
114 /* asserts to verify all state is correct here */
115 ASSERT(atomic_read(&ip->i_pincount) == 0);
116 XFS_STATS_DEC(ip->i_mount, vn_active);
117
118 call_rcu(&VFS_I(ip)->i_rcu, xfs_inode_free_callback);
119}
120
121void
122xfs_inode_free(
123 struct xfs_inode *ip)
124{
125 ASSERT(!xfs_isiflocked(ip));
126
127 /*
128 * Because we use RCU freeing we need to ensure the inode always
129 * appears to be reclaimed with an invalid inode number when in the
130 * free state. The ip->i_flags_lock provides the barrier against lookup
131 * races.
132 */
133 spin_lock(&ip->i_flags_lock);
134 ip->i_flags = XFS_IRECLAIM;
135 ip->i_ino = 0;
136 spin_unlock(&ip->i_flags_lock);
137
138 __xfs_inode_free(ip);
139}
140
141/*
142 * Queue a new inode reclaim pass if there are reclaimable inodes and there
143 * isn't a reclaim pass already in progress. By default it runs every 5s based
144 * on the xfs periodic sync default of 30s. Perhaps this should have it's own
145 * tunable, but that can be done if this method proves to be ineffective or too
146 * aggressive.
147 */
148static void
149xfs_reclaim_work_queue(
150 struct xfs_mount *mp)
151{
152
153 rcu_read_lock();
154 if (radix_tree_tagged(&mp->m_perag_tree, XFS_ICI_RECLAIM_TAG)) {
155 queue_delayed_work(mp->m_reclaim_workqueue, &mp->m_reclaim_work,
156 msecs_to_jiffies(xfs_syncd_centisecs / 6 * 10));
157 }
158 rcu_read_unlock();
159}
160
161/*
162 * This is a fast pass over the inode cache to try to get reclaim moving on as
163 * many inodes as possible in a short period of time. It kicks itself every few
164 * seconds, as well as being kicked by the inode cache shrinker when memory
165 * goes low. It scans as quickly as possible avoiding locked inodes or those
166 * already being flushed, and once done schedules a future pass.
167 */
168void
169xfs_reclaim_worker(
170 struct work_struct *work)
171{
172 struct xfs_mount *mp = container_of(to_delayed_work(work),
173 struct xfs_mount, m_reclaim_work);
174
175 xfs_reclaim_inodes(mp, SYNC_TRYLOCK);
176 xfs_reclaim_work_queue(mp);
177}
178
179static void
180xfs_perag_set_reclaim_tag(
181 struct xfs_perag *pag)
182{
183 struct xfs_mount *mp = pag->pag_mount;
184
185 lockdep_assert_held(&pag->pag_ici_lock);
186 if (pag->pag_ici_reclaimable++)
187 return;
188
189 /* propagate the reclaim tag up into the perag radix tree */
190 spin_lock(&mp->m_perag_lock);
191 radix_tree_tag_set(&mp->m_perag_tree, pag->pag_agno,
192 XFS_ICI_RECLAIM_TAG);
193 spin_unlock(&mp->m_perag_lock);
194
195 /* schedule periodic background inode reclaim */
196 xfs_reclaim_work_queue(mp);
197
198 trace_xfs_perag_set_reclaim(mp, pag->pag_agno, -1, _RET_IP_);
199}
200
201static void
202xfs_perag_clear_reclaim_tag(
203 struct xfs_perag *pag)
204{
205 struct xfs_mount *mp = pag->pag_mount;
206
207 lockdep_assert_held(&pag->pag_ici_lock);
208 if (--pag->pag_ici_reclaimable)
209 return;
210
211 /* clear the reclaim tag from the perag radix tree */
212 spin_lock(&mp->m_perag_lock);
213 radix_tree_tag_clear(&mp->m_perag_tree, pag->pag_agno,
214 XFS_ICI_RECLAIM_TAG);
215 spin_unlock(&mp->m_perag_lock);
216 trace_xfs_perag_clear_reclaim(mp, pag->pag_agno, -1, _RET_IP_);
217}
218
219
220/*
221 * We set the inode flag atomically with the radix tree tag.
222 * Once we get tag lookups on the radix tree, this inode flag
223 * can go away.
224 */
225void
226xfs_inode_set_reclaim_tag(
227 struct xfs_inode *ip)
228{
229 struct xfs_mount *mp = ip->i_mount;
230 struct xfs_perag *pag;
231
232 pag = xfs_perag_get(mp, XFS_INO_TO_AGNO(mp, ip->i_ino));
233 spin_lock(&pag->pag_ici_lock);
234 spin_lock(&ip->i_flags_lock);
235
236 radix_tree_tag_set(&pag->pag_ici_root, XFS_INO_TO_AGINO(mp, ip->i_ino),
237 XFS_ICI_RECLAIM_TAG);
238 xfs_perag_set_reclaim_tag(pag);
239 __xfs_iflags_set(ip, XFS_IRECLAIMABLE);
240
241 spin_unlock(&ip->i_flags_lock);
242 spin_unlock(&pag->pag_ici_lock);
243 xfs_perag_put(pag);
244}
245
246STATIC void
247xfs_inode_clear_reclaim_tag(
248 struct xfs_perag *pag,
249 xfs_ino_t ino)
250{
251 radix_tree_tag_clear(&pag->pag_ici_root,
252 XFS_INO_TO_AGINO(pag->pag_mount, ino),
253 XFS_ICI_RECLAIM_TAG);
254 xfs_perag_clear_reclaim_tag(pag);
255}
256
257static void
258xfs_inew_wait(
259 struct xfs_inode *ip)
260{
261 wait_queue_head_t *wq = bit_waitqueue(&ip->i_flags, __XFS_INEW_BIT);
262 DEFINE_WAIT_BIT(wait, &ip->i_flags, __XFS_INEW_BIT);
263
264 do {
265 prepare_to_wait(wq, &wait.wq_entry, TASK_UNINTERRUPTIBLE);
266 if (!xfs_iflags_test(ip, XFS_INEW))
267 break;
268 schedule();
269 } while (true);
270 finish_wait(wq, &wait.wq_entry);
271}
272
273/*
274 * When we recycle a reclaimable inode, we need to re-initialise the VFS inode
275 * part of the structure. This is made more complex by the fact we store
276 * information about the on-disk values in the VFS inode and so we can't just
277 * overwrite the values unconditionally. Hence we save the parameters we
278 * need to retain across reinitialisation, and rewrite them into the VFS inode
279 * after reinitialisation even if it fails.
280 */
281static int
282xfs_reinit_inode(
283 struct xfs_mount *mp,
284 struct inode *inode)
285{
286 int error;
287 uint32_t nlink = inode->i_nlink;
288 uint32_t generation = inode->i_generation;
289 uint64_t version = inode_peek_iversion(inode);
290 umode_t mode = inode->i_mode;
291 dev_t dev = inode->i_rdev;
292
293 error = inode_init_always(mp->m_super, inode);
294
295 set_nlink(inode, nlink);
296 inode->i_generation = generation;
297 inode_set_iversion_queried(inode, version);
298 inode->i_mode = mode;
299 inode->i_rdev = dev;
300 return error;
301}
302
303/*
304 * If we are allocating a new inode, then check what was returned is
305 * actually a free, empty inode. If we are not allocating an inode,
306 * then check we didn't find a free inode.
307 *
308 * Returns:
309 * 0 if the inode free state matches the lookup context
310 * -ENOENT if the inode is free and we are not allocating
311 * -EFSCORRUPTED if there is any state mismatch at all
312 */
313static int
314xfs_iget_check_free_state(
315 struct xfs_inode *ip,
316 int flags)
317{
318 if (flags & XFS_IGET_CREATE) {
319 /* should be a free inode */
320 if (VFS_I(ip)->i_mode != 0) {
321 xfs_warn(ip->i_mount,
322"Corruption detected! Free inode 0x%llx not marked free! (mode 0x%x)",
323 ip->i_ino, VFS_I(ip)->i_mode);
324 return -EFSCORRUPTED;
325 }
326
327 if (ip->i_d.di_nblocks != 0) {
328 xfs_warn(ip->i_mount,
329"Corruption detected! Free inode 0x%llx has blocks allocated!",
330 ip->i_ino);
331 return -EFSCORRUPTED;
332 }
333 return 0;
334 }
335
336 /* should be an allocated inode */
337 if (VFS_I(ip)->i_mode == 0)
338 return -ENOENT;
339
340 return 0;
341}
342
343/*
344 * Check the validity of the inode we just found it the cache
345 */
346static int
347xfs_iget_cache_hit(
348 struct xfs_perag *pag,
349 struct xfs_inode *ip,
350 xfs_ino_t ino,
351 int flags,
352 int lock_flags) __releases(RCU)
353{
354 struct inode *inode = VFS_I(ip);
355 struct xfs_mount *mp = ip->i_mount;
356 int error;
357
358 /*
359 * check for re-use of an inode within an RCU grace period due to the
360 * radix tree nodes not being updated yet. We monitor for this by
361 * setting the inode number to zero before freeing the inode structure.
362 * If the inode has been reallocated and set up, then the inode number
363 * will not match, so check for that, too.
364 */
365 spin_lock(&ip->i_flags_lock);
366 if (ip->i_ino != ino) {
367 trace_xfs_iget_skip(ip);
368 XFS_STATS_INC(mp, xs_ig_frecycle);
369 error = -EAGAIN;
370 goto out_error;
371 }
372
373
374 /*
375 * If we are racing with another cache hit that is currently
376 * instantiating this inode or currently recycling it out of
377 * reclaimabe state, wait for the initialisation to complete
378 * before continuing.
379 *
380 * XXX(hch): eventually we should do something equivalent to
381 * wait_on_inode to wait for these flags to be cleared
382 * instead of polling for it.
383 */
384 if (ip->i_flags & (XFS_INEW|XFS_IRECLAIM)) {
385 trace_xfs_iget_skip(ip);
386 XFS_STATS_INC(mp, xs_ig_frecycle);
387 error = -EAGAIN;
388 goto out_error;
389 }
390
391 /*
392 * Check the inode free state is valid. This also detects lookup
393 * racing with unlinks.
394 */
395 error = xfs_iget_check_free_state(ip, flags);
396 if (error)
397 goto out_error;
398
399 /*
400 * If IRECLAIMABLE is set, we've torn down the VFS inode already.
401 * Need to carefully get it back into useable state.
402 */
403 if (ip->i_flags & XFS_IRECLAIMABLE) {
404 trace_xfs_iget_reclaim(ip);
405
406 if (flags & XFS_IGET_INCORE) {
407 error = -EAGAIN;
408 goto out_error;
409 }
410
411 /*
412 * We need to set XFS_IRECLAIM to prevent xfs_reclaim_inode
413 * from stomping over us while we recycle the inode. We can't
414 * clear the radix tree reclaimable tag yet as it requires
415 * pag_ici_lock to be held exclusive.
416 */
417 ip->i_flags |= XFS_IRECLAIM;
418
419 spin_unlock(&ip->i_flags_lock);
420 rcu_read_unlock();
421
422 error = xfs_reinit_inode(mp, inode);
423 if (error) {
424 bool wake;
425 /*
426 * Re-initializing the inode failed, and we are in deep
427 * trouble. Try to re-add it to the reclaim list.
428 */
429 rcu_read_lock();
430 spin_lock(&ip->i_flags_lock);
431 wake = !!__xfs_iflags_test(ip, XFS_INEW);
432 ip->i_flags &= ~(XFS_INEW | XFS_IRECLAIM);
433 if (wake)
434 wake_up_bit(&ip->i_flags, __XFS_INEW_BIT);
435 ASSERT(ip->i_flags & XFS_IRECLAIMABLE);
436 trace_xfs_iget_reclaim_fail(ip);
437 goto out_error;
438 }
439
440 spin_lock(&pag->pag_ici_lock);
441 spin_lock(&ip->i_flags_lock);
442
443 /*
444 * Clear the per-lifetime state in the inode as we are now
445 * effectively a new inode and need to return to the initial
446 * state before reuse occurs.
447 */
448 ip->i_flags &= ~XFS_IRECLAIM_RESET_FLAGS;
449 ip->i_flags |= XFS_INEW;
450 xfs_inode_clear_reclaim_tag(pag, ip->i_ino);
451 inode->i_state = I_NEW;
452 ip->i_sick = 0;
453 ip->i_checked = 0;
454
455 ASSERT(!rwsem_is_locked(&inode->i_rwsem));
456 init_rwsem(&inode->i_rwsem);
457
458 spin_unlock(&ip->i_flags_lock);
459 spin_unlock(&pag->pag_ici_lock);
460 } else {
461 /* If the VFS inode is being torn down, pause and try again. */
462 if (!igrab(inode)) {
463 trace_xfs_iget_skip(ip);
464 error = -EAGAIN;
465 goto out_error;
466 }
467
468 /* We've got a live one. */
469 spin_unlock(&ip->i_flags_lock);
470 rcu_read_unlock();
471 trace_xfs_iget_hit(ip);
472 }
473
474 if (lock_flags != 0)
475 xfs_ilock(ip, lock_flags);
476
477 if (!(flags & XFS_IGET_INCORE))
478 xfs_iflags_clear(ip, XFS_ISTALE | XFS_IDONTCACHE);
479 XFS_STATS_INC(mp, xs_ig_found);
480
481 return 0;
482
483out_error:
484 spin_unlock(&ip->i_flags_lock);
485 rcu_read_unlock();
486 return error;
487}
488
489
490static int
491xfs_iget_cache_miss(
492 struct xfs_mount *mp,
493 struct xfs_perag *pag,
494 xfs_trans_t *tp,
495 xfs_ino_t ino,
496 struct xfs_inode **ipp,
497 int flags,
498 int lock_flags)
499{
500 struct xfs_inode *ip;
501 int error;
502 xfs_agino_t agino = XFS_INO_TO_AGINO(mp, ino);
503 int iflags;
504
505 ip = xfs_inode_alloc(mp, ino);
506 if (!ip)
507 return -ENOMEM;
508
509 error = xfs_iread(mp, tp, ip, flags);
510 if (error)
511 goto out_destroy;
512
513 if (!xfs_inode_verify_forks(ip)) {
514 error = -EFSCORRUPTED;
515 goto out_destroy;
516 }
517
518 trace_xfs_iget_miss(ip);
519
520
521 /*
522 * Check the inode free state is valid. This also detects lookup
523 * racing with unlinks.
524 */
525 error = xfs_iget_check_free_state(ip, flags);
526 if (error)
527 goto out_destroy;
528
529 /*
530 * Preload the radix tree so we can insert safely under the
531 * write spinlock. Note that we cannot sleep inside the preload
532 * region. Since we can be called from transaction context, don't
533 * recurse into the file system.
534 */
535 if (radix_tree_preload(GFP_NOFS)) {
536 error = -EAGAIN;
537 goto out_destroy;
538 }
539
540 /*
541 * Because the inode hasn't been added to the radix-tree yet it can't
542 * be found by another thread, so we can do the non-sleeping lock here.
543 */
544 if (lock_flags) {
545 if (!xfs_ilock_nowait(ip, lock_flags))
546 BUG();
547 }
548
549 /*
550 * These values must be set before inserting the inode into the radix
551 * tree as the moment it is inserted a concurrent lookup (allowed by the
552 * RCU locking mechanism) can find it and that lookup must see that this
553 * is an inode currently under construction (i.e. that XFS_INEW is set).
554 * The ip->i_flags_lock that protects the XFS_INEW flag forms the
555 * memory barrier that ensures this detection works correctly at lookup
556 * time.
557 */
558 iflags = XFS_INEW;
559 if (flags & XFS_IGET_DONTCACHE)
560 iflags |= XFS_IDONTCACHE;
561 ip->i_udquot = NULL;
562 ip->i_gdquot = NULL;
563 ip->i_pdquot = NULL;
564 xfs_iflags_set(ip, iflags);
565
566 /* insert the new inode */
567 spin_lock(&pag->pag_ici_lock);
568 error = radix_tree_insert(&pag->pag_ici_root, agino, ip);
569 if (unlikely(error)) {
570 WARN_ON(error != -EEXIST);
571 XFS_STATS_INC(mp, xs_ig_dup);
572 error = -EAGAIN;
573 goto out_preload_end;
574 }
575 spin_unlock(&pag->pag_ici_lock);
576 radix_tree_preload_end();
577
578 *ipp = ip;
579 return 0;
580
581out_preload_end:
582 spin_unlock(&pag->pag_ici_lock);
583 radix_tree_preload_end();
584 if (lock_flags)
585 xfs_iunlock(ip, lock_flags);
586out_destroy:
587 __destroy_inode(VFS_I(ip));
588 xfs_inode_free(ip);
589 return error;
590}
591
592/*
593 * Look up an inode by number in the given file system.
594 * The inode is looked up in the cache held in each AG.
595 * If the inode is found in the cache, initialise the vfs inode
596 * if necessary.
597 *
598 * If it is not in core, read it in from the file system's device,
599 * add it to the cache and initialise the vfs inode.
600 *
601 * The inode is locked according to the value of the lock_flags parameter.
602 * This flag parameter indicates how and if the inode's IO lock and inode lock
603 * should be taken.
604 *
605 * mp -- the mount point structure for the current file system. It points
606 * to the inode hash table.
607 * tp -- a pointer to the current transaction if there is one. This is
608 * simply passed through to the xfs_iread() call.
609 * ino -- the number of the inode desired. This is the unique identifier
610 * within the file system for the inode being requested.
611 * lock_flags -- flags indicating how to lock the inode. See the comment
612 * for xfs_ilock() for a list of valid values.
613 */
614int
615xfs_iget(
616 xfs_mount_t *mp,
617 xfs_trans_t *tp,
618 xfs_ino_t ino,
619 uint flags,
620 uint lock_flags,
621 xfs_inode_t **ipp)
622{
623 xfs_inode_t *ip;
624 int error;
625 xfs_perag_t *pag;
626 xfs_agino_t agino;
627
628 /*
629 * xfs_reclaim_inode() uses the ILOCK to ensure an inode
630 * doesn't get freed while it's being referenced during a
631 * radix tree traversal here. It assumes this function
632 * aqcuires only the ILOCK (and therefore it has no need to
633 * involve the IOLOCK in this synchronization).
634 */
635 ASSERT((lock_flags & (XFS_IOLOCK_EXCL | XFS_IOLOCK_SHARED)) == 0);
636
637 /* reject inode numbers outside existing AGs */
638 if (!ino || XFS_INO_TO_AGNO(mp, ino) >= mp->m_sb.sb_agcount)
639 return -EINVAL;
640
641 XFS_STATS_INC(mp, xs_ig_attempts);
642
643 /* get the perag structure and ensure that it's inode capable */
644 pag = xfs_perag_get(mp, XFS_INO_TO_AGNO(mp, ino));
645 agino = XFS_INO_TO_AGINO(mp, ino);
646
647again:
648 error = 0;
649 rcu_read_lock();
650 ip = radix_tree_lookup(&pag->pag_ici_root, agino);
651
652 if (ip) {
653 error = xfs_iget_cache_hit(pag, ip, ino, flags, lock_flags);
654 if (error)
655 goto out_error_or_again;
656 } else {
657 rcu_read_unlock();
658 if (flags & XFS_IGET_INCORE) {
659 error = -ENODATA;
660 goto out_error_or_again;
661 }
662 XFS_STATS_INC(mp, xs_ig_missed);
663
664 error = xfs_iget_cache_miss(mp, pag, tp, ino, &ip,
665 flags, lock_flags);
666 if (error)
667 goto out_error_or_again;
668 }
669 xfs_perag_put(pag);
670
671 *ipp = ip;
672
673 /*
674 * If we have a real type for an on-disk inode, we can setup the inode
675 * now. If it's a new inode being created, xfs_ialloc will handle it.
676 */
677 if (xfs_iflags_test(ip, XFS_INEW) && VFS_I(ip)->i_mode != 0)
678 xfs_setup_existing_inode(ip);
679 return 0;
680
681out_error_or_again:
682 if (!(flags & XFS_IGET_INCORE) && error == -EAGAIN) {
683 delay(1);
684 goto again;
685 }
686 xfs_perag_put(pag);
687 return error;
688}
689
690/*
691 * "Is this a cached inode that's also allocated?"
692 *
693 * Look up an inode by number in the given file system. If the inode is
694 * in cache and isn't in purgatory, return 1 if the inode is allocated
695 * and 0 if it is not. For all other cases (not in cache, being torn
696 * down, etc.), return a negative error code.
697 *
698 * The caller has to prevent inode allocation and freeing activity,
699 * presumably by locking the AGI buffer. This is to ensure that an
700 * inode cannot transition from allocated to freed until the caller is
701 * ready to allow that. If the inode is in an intermediate state (new,
702 * reclaimable, or being reclaimed), -EAGAIN will be returned; if the
703 * inode is not in the cache, -ENOENT will be returned. The caller must
704 * deal with these scenarios appropriately.
705 *
706 * This is a specialized use case for the online scrubber; if you're
707 * reading this, you probably want xfs_iget.
708 */
709int
710xfs_icache_inode_is_allocated(
711 struct xfs_mount *mp,
712 struct xfs_trans *tp,
713 xfs_ino_t ino,
714 bool *inuse)
715{
716 struct xfs_inode *ip;
717 int error;
718
719 error = xfs_iget(mp, tp, ino, XFS_IGET_INCORE, 0, &ip);
720 if (error)
721 return error;
722
723 *inuse = !!(VFS_I(ip)->i_mode);
724 xfs_irele(ip);
725 return 0;
726}
727
728/*
729 * The inode lookup is done in batches to keep the amount of lock traffic and
730 * radix tree lookups to a minimum. The batch size is a trade off between
731 * lookup reduction and stack usage. This is in the reclaim path, so we can't
732 * be too greedy.
733 */
734#define XFS_LOOKUP_BATCH 32
735
736STATIC int
737xfs_inode_ag_walk_grab(
738 struct xfs_inode *ip,
739 int flags)
740{
741 struct inode *inode = VFS_I(ip);
742 bool newinos = !!(flags & XFS_AGITER_INEW_WAIT);
743
744 ASSERT(rcu_read_lock_held());
745
746 /*
747 * check for stale RCU freed inode
748 *
749 * If the inode has been reallocated, it doesn't matter if it's not in
750 * the AG we are walking - we are walking for writeback, so if it
751 * passes all the "valid inode" checks and is dirty, then we'll write
752 * it back anyway. If it has been reallocated and still being
753 * initialised, the XFS_INEW check below will catch it.
754 */
755 spin_lock(&ip->i_flags_lock);
756 if (!ip->i_ino)
757 goto out_unlock_noent;
758
759 /* avoid new or reclaimable inodes. Leave for reclaim code to flush */
760 if ((!newinos && __xfs_iflags_test(ip, XFS_INEW)) ||
761 __xfs_iflags_test(ip, XFS_IRECLAIMABLE | XFS_IRECLAIM))
762 goto out_unlock_noent;
763 spin_unlock(&ip->i_flags_lock);
764
765 /* nothing to sync during shutdown */
766 if (XFS_FORCED_SHUTDOWN(ip->i_mount))
767 return -EFSCORRUPTED;
768
769 /* If we can't grab the inode, it must on it's way to reclaim. */
770 if (!igrab(inode))
771 return -ENOENT;
772
773 /* inode is valid */
774 return 0;
775
776out_unlock_noent:
777 spin_unlock(&ip->i_flags_lock);
778 return -ENOENT;
779}
780
781STATIC int
782xfs_inode_ag_walk(
783 struct xfs_mount *mp,
784 struct xfs_perag *pag,
785 int (*execute)(struct xfs_inode *ip, int flags,
786 void *args),
787 int flags,
788 void *args,
789 int tag,
790 int iter_flags)
791{
792 uint32_t first_index;
793 int last_error = 0;
794 int skipped;
795 int done;
796 int nr_found;
797
798restart:
799 done = 0;
800 skipped = 0;
801 first_index = 0;
802 nr_found = 0;
803 do {
804 struct xfs_inode *batch[XFS_LOOKUP_BATCH];
805 int error = 0;
806 int i;
807
808 rcu_read_lock();
809
810 if (tag == -1)
811 nr_found = radix_tree_gang_lookup(&pag->pag_ici_root,
812 (void **)batch, first_index,
813 XFS_LOOKUP_BATCH);
814 else
815 nr_found = radix_tree_gang_lookup_tag(
816 &pag->pag_ici_root,
817 (void **) batch, first_index,
818 XFS_LOOKUP_BATCH, tag);
819
820 if (!nr_found) {
821 rcu_read_unlock();
822 break;
823 }
824
825 /*
826 * Grab the inodes before we drop the lock. if we found
827 * nothing, nr == 0 and the loop will be skipped.
828 */
829 for (i = 0; i < nr_found; i++) {
830 struct xfs_inode *ip = batch[i];
831
832 if (done || xfs_inode_ag_walk_grab(ip, iter_flags))
833 batch[i] = NULL;
834
835 /*
836 * Update the index for the next lookup. Catch
837 * overflows into the next AG range which can occur if
838 * we have inodes in the last block of the AG and we
839 * are currently pointing to the last inode.
840 *
841 * Because we may see inodes that are from the wrong AG
842 * due to RCU freeing and reallocation, only update the
843 * index if it lies in this AG. It was a race that lead
844 * us to see this inode, so another lookup from the
845 * same index will not find it again.
846 */
847 if (XFS_INO_TO_AGNO(mp, ip->i_ino) != pag->pag_agno)
848 continue;
849 first_index = XFS_INO_TO_AGINO(mp, ip->i_ino + 1);
850 if (first_index < XFS_INO_TO_AGINO(mp, ip->i_ino))
851 done = 1;
852 }
853
854 /* unlock now we've grabbed the inodes. */
855 rcu_read_unlock();
856
857 for (i = 0; i < nr_found; i++) {
858 if (!batch[i])
859 continue;
860 if ((iter_flags & XFS_AGITER_INEW_WAIT) &&
861 xfs_iflags_test(batch[i], XFS_INEW))
862 xfs_inew_wait(batch[i]);
863 error = execute(batch[i], flags, args);
864 xfs_irele(batch[i]);
865 if (error == -EAGAIN) {
866 skipped++;
867 continue;
868 }
869 if (error && last_error != -EFSCORRUPTED)
870 last_error = error;
871 }
872
873 /* bail out if the filesystem is corrupted. */
874 if (error == -EFSCORRUPTED)
875 break;
876
877 cond_resched();
878
879 } while (nr_found && !done);
880
881 if (skipped) {
882 delay(1);
883 goto restart;
884 }
885 return last_error;
886}
887
888/*
889 * Background scanning to trim post-EOF preallocated space. This is queued
890 * based on the 'speculative_prealloc_lifetime' tunable (5m by default).
891 */
892void
893xfs_queue_eofblocks(
894 struct xfs_mount *mp)
895{
896 rcu_read_lock();
897 if (radix_tree_tagged(&mp->m_perag_tree, XFS_ICI_EOFBLOCKS_TAG))
898 queue_delayed_work(mp->m_eofblocks_workqueue,
899 &mp->m_eofblocks_work,
900 msecs_to_jiffies(xfs_eofb_secs * 1000));
901 rcu_read_unlock();
902}
903
904void
905xfs_eofblocks_worker(
906 struct work_struct *work)
907{
908 struct xfs_mount *mp = container_of(to_delayed_work(work),
909 struct xfs_mount, m_eofblocks_work);
910 xfs_icache_free_eofblocks(mp, NULL);
911 xfs_queue_eofblocks(mp);
912}
913
914/*
915 * Background scanning to trim preallocated CoW space. This is queued
916 * based on the 'speculative_cow_prealloc_lifetime' tunable (5m by default).
917 * (We'll just piggyback on the post-EOF prealloc space workqueue.)
918 */
919void
920xfs_queue_cowblocks(
921 struct xfs_mount *mp)
922{
923 rcu_read_lock();
924 if (radix_tree_tagged(&mp->m_perag_tree, XFS_ICI_COWBLOCKS_TAG))
925 queue_delayed_work(mp->m_eofblocks_workqueue,
926 &mp->m_cowblocks_work,
927 msecs_to_jiffies(xfs_cowb_secs * 1000));
928 rcu_read_unlock();
929}
930
931void
932xfs_cowblocks_worker(
933 struct work_struct *work)
934{
935 struct xfs_mount *mp = container_of(to_delayed_work(work),
936 struct xfs_mount, m_cowblocks_work);
937 xfs_icache_free_cowblocks(mp, NULL);
938 xfs_queue_cowblocks(mp);
939}
940
941int
942xfs_inode_ag_iterator_flags(
943 struct xfs_mount *mp,
944 int (*execute)(struct xfs_inode *ip, int flags,
945 void *args),
946 int flags,
947 void *args,
948 int iter_flags)
949{
950 struct xfs_perag *pag;
951 int error = 0;
952 int last_error = 0;
953 xfs_agnumber_t ag;
954
955 ag = 0;
956 while ((pag = xfs_perag_get(mp, ag))) {
957 ag = pag->pag_agno + 1;
958 error = xfs_inode_ag_walk(mp, pag, execute, flags, args, -1,
959 iter_flags);
960 xfs_perag_put(pag);
961 if (error) {
962 last_error = error;
963 if (error == -EFSCORRUPTED)
964 break;
965 }
966 }
967 return last_error;
968}
969
970int
971xfs_inode_ag_iterator(
972 struct xfs_mount *mp,
973 int (*execute)(struct xfs_inode *ip, int flags,
974 void *args),
975 int flags,
976 void *args)
977{
978 return xfs_inode_ag_iterator_flags(mp, execute, flags, args, 0);
979}
980
981int
982xfs_inode_ag_iterator_tag(
983 struct xfs_mount *mp,
984 int (*execute)(struct xfs_inode *ip, int flags,
985 void *args),
986 int flags,
987 void *args,
988 int tag)
989{
990 struct xfs_perag *pag;
991 int error = 0;
992 int last_error = 0;
993 xfs_agnumber_t ag;
994
995 ag = 0;
996 while ((pag = xfs_perag_get_tag(mp, ag, tag))) {
997 ag = pag->pag_agno + 1;
998 error = xfs_inode_ag_walk(mp, pag, execute, flags, args, tag,
999 0);
1000 xfs_perag_put(pag);
1001 if (error) {
1002 last_error = error;
1003 if (error == -EFSCORRUPTED)
1004 break;
1005 }
1006 }
1007 return last_error;
1008}
1009
1010/*
1011 * Grab the inode for reclaim exclusively.
1012 * Return 0 if we grabbed it, non-zero otherwise.
1013 */
1014STATIC int
1015xfs_reclaim_inode_grab(
1016 struct xfs_inode *ip,
1017 int flags)
1018{
1019 ASSERT(rcu_read_lock_held());
1020
1021 /* quick check for stale RCU freed inode */
1022 if (!ip->i_ino)
1023 return 1;
1024
1025 /*
1026 * If we are asked for non-blocking operation, do unlocked checks to
1027 * see if the inode already is being flushed or in reclaim to avoid
1028 * lock traffic.
1029 */
1030 if ((flags & SYNC_TRYLOCK) &&
1031 __xfs_iflags_test(ip, XFS_IFLOCK | XFS_IRECLAIM))
1032 return 1;
1033
1034 /*
1035 * The radix tree lock here protects a thread in xfs_iget from racing
1036 * with us starting reclaim on the inode. Once we have the
1037 * XFS_IRECLAIM flag set it will not touch us.
1038 *
1039 * Due to RCU lookup, we may find inodes that have been freed and only
1040 * have XFS_IRECLAIM set. Indeed, we may see reallocated inodes that
1041 * aren't candidates for reclaim at all, so we must check the
1042 * XFS_IRECLAIMABLE is set first before proceeding to reclaim.
1043 */
1044 spin_lock(&ip->i_flags_lock);
1045 if (!__xfs_iflags_test(ip, XFS_IRECLAIMABLE) ||
1046 __xfs_iflags_test(ip, XFS_IRECLAIM)) {
1047 /* not a reclaim candidate. */
1048 spin_unlock(&ip->i_flags_lock);
1049 return 1;
1050 }
1051 __xfs_iflags_set(ip, XFS_IRECLAIM);
1052 spin_unlock(&ip->i_flags_lock);
1053 return 0;
1054}
1055
1056/*
1057 * Inodes in different states need to be treated differently. The following
1058 * table lists the inode states and the reclaim actions necessary:
1059 *
1060 * inode state iflush ret required action
1061 * --------------- ---------- ---------------
1062 * bad - reclaim
1063 * shutdown EIO unpin and reclaim
1064 * clean, unpinned 0 reclaim
1065 * stale, unpinned 0 reclaim
1066 * clean, pinned(*) 0 requeue
1067 * stale, pinned EAGAIN requeue
1068 * dirty, async - requeue
1069 * dirty, sync 0 reclaim
1070 *
1071 * (*) dgc: I don't think the clean, pinned state is possible but it gets
1072 * handled anyway given the order of checks implemented.
1073 *
1074 * Also, because we get the flush lock first, we know that any inode that has
1075 * been flushed delwri has had the flush completed by the time we check that
1076 * the inode is clean.
1077 *
1078 * Note that because the inode is flushed delayed write by AIL pushing, the
1079 * flush lock may already be held here and waiting on it can result in very
1080 * long latencies. Hence for sync reclaims, where we wait on the flush lock,
1081 * the caller should push the AIL first before trying to reclaim inodes to
1082 * minimise the amount of time spent waiting. For background relaim, we only
1083 * bother to reclaim clean inodes anyway.
1084 *
1085 * Hence the order of actions after gaining the locks should be:
1086 * bad => reclaim
1087 * shutdown => unpin and reclaim
1088 * pinned, async => requeue
1089 * pinned, sync => unpin
1090 * stale => reclaim
1091 * clean => reclaim
1092 * dirty, async => requeue
1093 * dirty, sync => flush, wait and reclaim
1094 */
1095STATIC int
1096xfs_reclaim_inode(
1097 struct xfs_inode *ip,
1098 struct xfs_perag *pag,
1099 int sync_mode)
1100{
1101 struct xfs_buf *bp = NULL;
1102 xfs_ino_t ino = ip->i_ino; /* for radix_tree_delete */
1103 int error;
1104
1105restart:
1106 error = 0;
1107 xfs_ilock(ip, XFS_ILOCK_EXCL);
1108 if (!xfs_iflock_nowait(ip)) {
1109 if (!(sync_mode & SYNC_WAIT))
1110 goto out;
1111 xfs_iflock(ip);
1112 }
1113
1114 if (XFS_FORCED_SHUTDOWN(ip->i_mount)) {
1115 xfs_iunpin_wait(ip);
1116 /* xfs_iflush_abort() drops the flush lock */
1117 xfs_iflush_abort(ip, false);
1118 goto reclaim;
1119 }
1120 if (xfs_ipincount(ip)) {
1121 if (!(sync_mode & SYNC_WAIT))
1122 goto out_ifunlock;
1123 xfs_iunpin_wait(ip);
1124 }
1125 if (xfs_iflags_test(ip, XFS_ISTALE) || xfs_inode_clean(ip)) {
1126 xfs_ifunlock(ip);
1127 goto reclaim;
1128 }
1129
1130 /*
1131 * Never flush out dirty data during non-blocking reclaim, as it would
1132 * just contend with AIL pushing trying to do the same job.
1133 */
1134 if (!(sync_mode & SYNC_WAIT))
1135 goto out_ifunlock;
1136
1137 /*
1138 * Now we have an inode that needs flushing.
1139 *
1140 * Note that xfs_iflush will never block on the inode buffer lock, as
1141 * xfs_ifree_cluster() can lock the inode buffer before it locks the
1142 * ip->i_lock, and we are doing the exact opposite here. As a result,
1143 * doing a blocking xfs_imap_to_bp() to get the cluster buffer would
1144 * result in an ABBA deadlock with xfs_ifree_cluster().
1145 *
1146 * As xfs_ifree_cluser() must gather all inodes that are active in the
1147 * cache to mark them stale, if we hit this case we don't actually want
1148 * to do IO here - we want the inode marked stale so we can simply
1149 * reclaim it. Hence if we get an EAGAIN error here, just unlock the
1150 * inode, back off and try again. Hopefully the next pass through will
1151 * see the stale flag set on the inode.
1152 */
1153 error = xfs_iflush(ip, &bp);
1154 if (error == -EAGAIN) {
1155 xfs_iunlock(ip, XFS_ILOCK_EXCL);
1156 /* backoff longer than in xfs_ifree_cluster */
1157 delay(2);
1158 goto restart;
1159 }
1160
1161 if (!error) {
1162 error = xfs_bwrite(bp);
1163 xfs_buf_relse(bp);
1164 }
1165
1166reclaim:
1167 ASSERT(!xfs_isiflocked(ip));
1168
1169 /*
1170 * Because we use RCU freeing we need to ensure the inode always appears
1171 * to be reclaimed with an invalid inode number when in the free state.
1172 * We do this as early as possible under the ILOCK so that
1173 * xfs_iflush_cluster() and xfs_ifree_cluster() can be guaranteed to
1174 * detect races with us here. By doing this, we guarantee that once
1175 * xfs_iflush_cluster() or xfs_ifree_cluster() has locked XFS_ILOCK that
1176 * it will see either a valid inode that will serialise correctly, or it
1177 * will see an invalid inode that it can skip.
1178 */
1179 spin_lock(&ip->i_flags_lock);
1180 ip->i_flags = XFS_IRECLAIM;
1181 ip->i_ino = 0;
1182 spin_unlock(&ip->i_flags_lock);
1183
1184 xfs_iunlock(ip, XFS_ILOCK_EXCL);
1185
1186 XFS_STATS_INC(ip->i_mount, xs_ig_reclaims);
1187 /*
1188 * Remove the inode from the per-AG radix tree.
1189 *
1190 * Because radix_tree_delete won't complain even if the item was never
1191 * added to the tree assert that it's been there before to catch
1192 * problems with the inode life time early on.
1193 */
1194 spin_lock(&pag->pag_ici_lock);
1195 if (!radix_tree_delete(&pag->pag_ici_root,
1196 XFS_INO_TO_AGINO(ip->i_mount, ino)))
1197 ASSERT(0);
1198 xfs_perag_clear_reclaim_tag(pag);
1199 spin_unlock(&pag->pag_ici_lock);
1200
1201 /*
1202 * Here we do an (almost) spurious inode lock in order to coordinate
1203 * with inode cache radix tree lookups. This is because the lookup
1204 * can reference the inodes in the cache without taking references.
1205 *
1206 * We make that OK here by ensuring that we wait until the inode is
1207 * unlocked after the lookup before we go ahead and free it.
1208 */
1209 xfs_ilock(ip, XFS_ILOCK_EXCL);
1210 xfs_qm_dqdetach(ip);
1211 xfs_iunlock(ip, XFS_ILOCK_EXCL);
1212
1213 __xfs_inode_free(ip);
1214 return error;
1215
1216out_ifunlock:
1217 xfs_ifunlock(ip);
1218out:
1219 xfs_iflags_clear(ip, XFS_IRECLAIM);
1220 xfs_iunlock(ip, XFS_ILOCK_EXCL);
1221 /*
1222 * We could return -EAGAIN here to make reclaim rescan the inode tree in
1223 * a short while. However, this just burns CPU time scanning the tree
1224 * waiting for IO to complete and the reclaim work never goes back to
1225 * the idle state. Instead, return 0 to let the next scheduled
1226 * background reclaim attempt to reclaim the inode again.
1227 */
1228 return 0;
1229}
1230
1231/*
1232 * Walk the AGs and reclaim the inodes in them. Even if the filesystem is
1233 * corrupted, we still want to try to reclaim all the inodes. If we don't,
1234 * then a shut down during filesystem unmount reclaim walk leak all the
1235 * unreclaimed inodes.
1236 */
1237STATIC int
1238xfs_reclaim_inodes_ag(
1239 struct xfs_mount *mp,
1240 int flags,
1241 int *nr_to_scan)
1242{
1243 struct xfs_perag *pag;
1244 int error = 0;
1245 int last_error = 0;
1246 xfs_agnumber_t ag;
1247 int trylock = flags & SYNC_TRYLOCK;
1248 int skipped;
1249
1250restart:
1251 ag = 0;
1252 skipped = 0;
1253 while ((pag = xfs_perag_get_tag(mp, ag, XFS_ICI_RECLAIM_TAG))) {
1254 unsigned long first_index = 0;
1255 int done = 0;
1256 int nr_found = 0;
1257
1258 ag = pag->pag_agno + 1;
1259
1260 if (trylock) {
1261 if (!mutex_trylock(&pag->pag_ici_reclaim_lock)) {
1262 skipped++;
1263 xfs_perag_put(pag);
1264 continue;
1265 }
1266 first_index = pag->pag_ici_reclaim_cursor;
1267 } else
1268 mutex_lock(&pag->pag_ici_reclaim_lock);
1269
1270 do {
1271 struct xfs_inode *batch[XFS_LOOKUP_BATCH];
1272 int i;
1273
1274 rcu_read_lock();
1275 nr_found = radix_tree_gang_lookup_tag(
1276 &pag->pag_ici_root,
1277 (void **)batch, first_index,
1278 XFS_LOOKUP_BATCH,
1279 XFS_ICI_RECLAIM_TAG);
1280 if (!nr_found) {
1281 done = 1;
1282 rcu_read_unlock();
1283 break;
1284 }
1285
1286 /*
1287 * Grab the inodes before we drop the lock. if we found
1288 * nothing, nr == 0 and the loop will be skipped.
1289 */
1290 for (i = 0; i < nr_found; i++) {
1291 struct xfs_inode *ip = batch[i];
1292
1293 if (done || xfs_reclaim_inode_grab(ip, flags))
1294 batch[i] = NULL;
1295
1296 /*
1297 * Update the index for the next lookup. Catch
1298 * overflows into the next AG range which can
1299 * occur if we have inodes in the last block of
1300 * the AG and we are currently pointing to the
1301 * last inode.
1302 *
1303 * Because we may see inodes that are from the
1304 * wrong AG due to RCU freeing and
1305 * reallocation, only update the index if it
1306 * lies in this AG. It was a race that lead us
1307 * to see this inode, so another lookup from
1308 * the same index will not find it again.
1309 */
1310 if (XFS_INO_TO_AGNO(mp, ip->i_ino) !=
1311 pag->pag_agno)
1312 continue;
1313 first_index = XFS_INO_TO_AGINO(mp, ip->i_ino + 1);
1314 if (first_index < XFS_INO_TO_AGINO(mp, ip->i_ino))
1315 done = 1;
1316 }
1317
1318 /* unlock now we've grabbed the inodes. */
1319 rcu_read_unlock();
1320
1321 for (i = 0; i < nr_found; i++) {
1322 if (!batch[i])
1323 continue;
1324 error = xfs_reclaim_inode(batch[i], pag, flags);
1325 if (error && last_error != -EFSCORRUPTED)
1326 last_error = error;
1327 }
1328
1329 *nr_to_scan -= XFS_LOOKUP_BATCH;
1330
1331 cond_resched();
1332
1333 } while (nr_found && !done && *nr_to_scan > 0);
1334
1335 if (trylock && !done)
1336 pag->pag_ici_reclaim_cursor = first_index;
1337 else
1338 pag->pag_ici_reclaim_cursor = 0;
1339 mutex_unlock(&pag->pag_ici_reclaim_lock);
1340 xfs_perag_put(pag);
1341 }
1342
1343 /*
1344 * if we skipped any AG, and we still have scan count remaining, do
1345 * another pass this time using blocking reclaim semantics (i.e
1346 * waiting on the reclaim locks and ignoring the reclaim cursors). This
1347 * ensure that when we get more reclaimers than AGs we block rather
1348 * than spin trying to execute reclaim.
1349 */
1350 if (skipped && (flags & SYNC_WAIT) && *nr_to_scan > 0) {
1351 trylock = 0;
1352 goto restart;
1353 }
1354 return last_error;
1355}
1356
1357int
1358xfs_reclaim_inodes(
1359 xfs_mount_t *mp,
1360 int mode)
1361{
1362 int nr_to_scan = INT_MAX;
1363
1364 return xfs_reclaim_inodes_ag(mp, mode, &nr_to_scan);
1365}
1366
1367/*
1368 * Scan a certain number of inodes for reclaim.
1369 *
1370 * When called we make sure that there is a background (fast) inode reclaim in
1371 * progress, while we will throttle the speed of reclaim via doing synchronous
1372 * reclaim of inodes. That means if we come across dirty inodes, we wait for
1373 * them to be cleaned, which we hope will not be very long due to the
1374 * background walker having already kicked the IO off on those dirty inodes.
1375 */
1376long
1377xfs_reclaim_inodes_nr(
1378 struct xfs_mount *mp,
1379 int nr_to_scan)
1380{
1381 /* kick background reclaimer and push the AIL */
1382 xfs_reclaim_work_queue(mp);
1383 xfs_ail_push_all(mp->m_ail);
1384
1385 return xfs_reclaim_inodes_ag(mp, SYNC_TRYLOCK | SYNC_WAIT, &nr_to_scan);
1386}
1387
1388/*
1389 * Return the number of reclaimable inodes in the filesystem for
1390 * the shrinker to determine how much to reclaim.
1391 */
1392int
1393xfs_reclaim_inodes_count(
1394 struct xfs_mount *mp)
1395{
1396 struct xfs_perag *pag;
1397 xfs_agnumber_t ag = 0;
1398 int reclaimable = 0;
1399
1400 while ((pag = xfs_perag_get_tag(mp, ag, XFS_ICI_RECLAIM_TAG))) {
1401 ag = pag->pag_agno + 1;
1402 reclaimable += pag->pag_ici_reclaimable;
1403 xfs_perag_put(pag);
1404 }
1405 return reclaimable;
1406}
1407
1408STATIC int
1409xfs_inode_match_id(
1410 struct xfs_inode *ip,
1411 struct xfs_eofblocks *eofb)
1412{
1413 if ((eofb->eof_flags & XFS_EOF_FLAGS_UID) &&
1414 !uid_eq(VFS_I(ip)->i_uid, eofb->eof_uid))
1415 return 0;
1416
1417 if ((eofb->eof_flags & XFS_EOF_FLAGS_GID) &&
1418 !gid_eq(VFS_I(ip)->i_gid, eofb->eof_gid))
1419 return 0;
1420
1421 if ((eofb->eof_flags & XFS_EOF_FLAGS_PRID) &&
1422 xfs_get_projid(ip) != eofb->eof_prid)
1423 return 0;
1424
1425 return 1;
1426}
1427
1428/*
1429 * A union-based inode filtering algorithm. Process the inode if any of the
1430 * criteria match. This is for global/internal scans only.
1431 */
1432STATIC int
1433xfs_inode_match_id_union(
1434 struct xfs_inode *ip,
1435 struct xfs_eofblocks *eofb)
1436{
1437 if ((eofb->eof_flags & XFS_EOF_FLAGS_UID) &&
1438 uid_eq(VFS_I(ip)->i_uid, eofb->eof_uid))
1439 return 1;
1440
1441 if ((eofb->eof_flags & XFS_EOF_FLAGS_GID) &&
1442 gid_eq(VFS_I(ip)->i_gid, eofb->eof_gid))
1443 return 1;
1444
1445 if ((eofb->eof_flags & XFS_EOF_FLAGS_PRID) &&
1446 xfs_get_projid(ip) == eofb->eof_prid)
1447 return 1;
1448
1449 return 0;
1450}
1451
1452STATIC int
1453xfs_inode_free_eofblocks(
1454 struct xfs_inode *ip,
1455 int flags,
1456 void *args)
1457{
1458 int ret = 0;
1459 struct xfs_eofblocks *eofb = args;
1460 int match;
1461
1462 if (!xfs_can_free_eofblocks(ip, false)) {
1463 /* inode could be preallocated or append-only */
1464 trace_xfs_inode_free_eofblocks_invalid(ip);
1465 xfs_inode_clear_eofblocks_tag(ip);
1466 return 0;
1467 }
1468
1469 /*
1470 * If the mapping is dirty the operation can block and wait for some
1471 * time. Unless we are waiting, skip it.
1472 */
1473 if (!(flags & SYNC_WAIT) &&
1474 mapping_tagged(VFS_I(ip)->i_mapping, PAGECACHE_TAG_DIRTY))
1475 return 0;
1476
1477 if (eofb) {
1478 if (eofb->eof_flags & XFS_EOF_FLAGS_UNION)
1479 match = xfs_inode_match_id_union(ip, eofb);
1480 else
1481 match = xfs_inode_match_id(ip, eofb);
1482 if (!match)
1483 return 0;
1484
1485 /* skip the inode if the file size is too small */
1486 if (eofb->eof_flags & XFS_EOF_FLAGS_MINFILESIZE &&
1487 XFS_ISIZE(ip) < eofb->eof_min_file_size)
1488 return 0;
1489 }
1490
1491 /*
1492 * If the caller is waiting, return -EAGAIN to keep the background
1493 * scanner moving and revisit the inode in a subsequent pass.
1494 */
1495 if (!xfs_ilock_nowait(ip, XFS_IOLOCK_EXCL)) {
1496 if (flags & SYNC_WAIT)
1497 ret = -EAGAIN;
1498 return ret;
1499 }
1500 ret = xfs_free_eofblocks(ip);
1501 xfs_iunlock(ip, XFS_IOLOCK_EXCL);
1502
1503 return ret;
1504}
1505
1506static int
1507__xfs_icache_free_eofblocks(
1508 struct xfs_mount *mp,
1509 struct xfs_eofblocks *eofb,
1510 int (*execute)(struct xfs_inode *ip, int flags,
1511 void *args),
1512 int tag)
1513{
1514 int flags = SYNC_TRYLOCK;
1515
1516 if (eofb && (eofb->eof_flags & XFS_EOF_FLAGS_SYNC))
1517 flags = SYNC_WAIT;
1518
1519 return xfs_inode_ag_iterator_tag(mp, execute, flags,
1520 eofb, tag);
1521}
1522
1523int
1524xfs_icache_free_eofblocks(
1525 struct xfs_mount *mp,
1526 struct xfs_eofblocks *eofb)
1527{
1528 return __xfs_icache_free_eofblocks(mp, eofb, xfs_inode_free_eofblocks,
1529 XFS_ICI_EOFBLOCKS_TAG);
1530}
1531
1532/*
1533 * Run eofblocks scans on the quotas applicable to the inode. For inodes with
1534 * multiple quotas, we don't know exactly which quota caused an allocation
1535 * failure. We make a best effort by including each quota under low free space
1536 * conditions (less than 1% free space) in the scan.
1537 */
1538static int
1539__xfs_inode_free_quota_eofblocks(
1540 struct xfs_inode *ip,
1541 int (*execute)(struct xfs_mount *mp,
1542 struct xfs_eofblocks *eofb))
1543{
1544 int scan = 0;
1545 struct xfs_eofblocks eofb = {0};
1546 struct xfs_dquot *dq;
1547
1548 /*
1549 * Run a sync scan to increase effectiveness and use the union filter to
1550 * cover all applicable quotas in a single scan.
1551 */
1552 eofb.eof_flags = XFS_EOF_FLAGS_UNION|XFS_EOF_FLAGS_SYNC;
1553
1554 if (XFS_IS_UQUOTA_ENFORCED(ip->i_mount)) {
1555 dq = xfs_inode_dquot(ip, XFS_DQ_USER);
1556 if (dq && xfs_dquot_lowsp(dq)) {
1557 eofb.eof_uid = VFS_I(ip)->i_uid;
1558 eofb.eof_flags |= XFS_EOF_FLAGS_UID;
1559 scan = 1;
1560 }
1561 }
1562
1563 if (XFS_IS_GQUOTA_ENFORCED(ip->i_mount)) {
1564 dq = xfs_inode_dquot(ip, XFS_DQ_GROUP);
1565 if (dq && xfs_dquot_lowsp(dq)) {
1566 eofb.eof_gid = VFS_I(ip)->i_gid;
1567 eofb.eof_flags |= XFS_EOF_FLAGS_GID;
1568 scan = 1;
1569 }
1570 }
1571
1572 if (scan)
1573 execute(ip->i_mount, &eofb);
1574
1575 return scan;
1576}
1577
1578int
1579xfs_inode_free_quota_eofblocks(
1580 struct xfs_inode *ip)
1581{
1582 return __xfs_inode_free_quota_eofblocks(ip, xfs_icache_free_eofblocks);
1583}
1584
1585static inline unsigned long
1586xfs_iflag_for_tag(
1587 int tag)
1588{
1589 switch (tag) {
1590 case XFS_ICI_EOFBLOCKS_TAG:
1591 return XFS_IEOFBLOCKS;
1592 case XFS_ICI_COWBLOCKS_TAG:
1593 return XFS_ICOWBLOCKS;
1594 default:
1595 ASSERT(0);
1596 return 0;
1597 }
1598}
1599
1600static void
1601__xfs_inode_set_blocks_tag(
1602 xfs_inode_t *ip,
1603 void (*execute)(struct xfs_mount *mp),
1604 void (*set_tp)(struct xfs_mount *mp, xfs_agnumber_t agno,
1605 int error, unsigned long caller_ip),
1606 int tag)
1607{
1608 struct xfs_mount *mp = ip->i_mount;
1609 struct xfs_perag *pag;
1610 int tagged;
1611
1612 /*
1613 * Don't bother locking the AG and looking up in the radix trees
1614 * if we already know that we have the tag set.
1615 */
1616 if (ip->i_flags & xfs_iflag_for_tag(tag))
1617 return;
1618 spin_lock(&ip->i_flags_lock);
1619 ip->i_flags |= xfs_iflag_for_tag(tag);
1620 spin_unlock(&ip->i_flags_lock);
1621
1622 pag = xfs_perag_get(mp, XFS_INO_TO_AGNO(mp, ip->i_ino));
1623 spin_lock(&pag->pag_ici_lock);
1624
1625 tagged = radix_tree_tagged(&pag->pag_ici_root, tag);
1626 radix_tree_tag_set(&pag->pag_ici_root,
1627 XFS_INO_TO_AGINO(ip->i_mount, ip->i_ino), tag);
1628 if (!tagged) {
1629 /* propagate the eofblocks tag up into the perag radix tree */
1630 spin_lock(&ip->i_mount->m_perag_lock);
1631 radix_tree_tag_set(&ip->i_mount->m_perag_tree,
1632 XFS_INO_TO_AGNO(ip->i_mount, ip->i_ino),
1633 tag);
1634 spin_unlock(&ip->i_mount->m_perag_lock);
1635
1636 /* kick off background trimming */
1637 execute(ip->i_mount);
1638
1639 set_tp(ip->i_mount, pag->pag_agno, -1, _RET_IP_);
1640 }
1641
1642 spin_unlock(&pag->pag_ici_lock);
1643 xfs_perag_put(pag);
1644}
1645
1646void
1647xfs_inode_set_eofblocks_tag(
1648 xfs_inode_t *ip)
1649{
1650 trace_xfs_inode_set_eofblocks_tag(ip);
1651 return __xfs_inode_set_blocks_tag(ip, xfs_queue_eofblocks,
1652 trace_xfs_perag_set_eofblocks,
1653 XFS_ICI_EOFBLOCKS_TAG);
1654}
1655
1656static void
1657__xfs_inode_clear_blocks_tag(
1658 xfs_inode_t *ip,
1659 void (*clear_tp)(struct xfs_mount *mp, xfs_agnumber_t agno,
1660 int error, unsigned long caller_ip),
1661 int tag)
1662{
1663 struct xfs_mount *mp = ip->i_mount;
1664 struct xfs_perag *pag;
1665
1666 spin_lock(&ip->i_flags_lock);
1667 ip->i_flags &= ~xfs_iflag_for_tag(tag);
1668 spin_unlock(&ip->i_flags_lock);
1669
1670 pag = xfs_perag_get(mp, XFS_INO_TO_AGNO(mp, ip->i_ino));
1671 spin_lock(&pag->pag_ici_lock);
1672
1673 radix_tree_tag_clear(&pag->pag_ici_root,
1674 XFS_INO_TO_AGINO(ip->i_mount, ip->i_ino), tag);
1675 if (!radix_tree_tagged(&pag->pag_ici_root, tag)) {
1676 /* clear the eofblocks tag from the perag radix tree */
1677 spin_lock(&ip->i_mount->m_perag_lock);
1678 radix_tree_tag_clear(&ip->i_mount->m_perag_tree,
1679 XFS_INO_TO_AGNO(ip->i_mount, ip->i_ino),
1680 tag);
1681 spin_unlock(&ip->i_mount->m_perag_lock);
1682 clear_tp(ip->i_mount, pag->pag_agno, -1, _RET_IP_);
1683 }
1684
1685 spin_unlock(&pag->pag_ici_lock);
1686 xfs_perag_put(pag);
1687}
1688
1689void
1690xfs_inode_clear_eofblocks_tag(
1691 xfs_inode_t *ip)
1692{
1693 trace_xfs_inode_clear_eofblocks_tag(ip);
1694 return __xfs_inode_clear_blocks_tag(ip,
1695 trace_xfs_perag_clear_eofblocks, XFS_ICI_EOFBLOCKS_TAG);
1696}
1697
1698/*
1699 * Set ourselves up to free CoW blocks from this file. If it's already clean
1700 * then we can bail out quickly, but otherwise we must back off if the file
1701 * is undergoing some kind of write.
1702 */
1703static bool
1704xfs_prep_free_cowblocks(
1705 struct xfs_inode *ip)
1706{
1707 /*
1708 * Just clear the tag if we have an empty cow fork or none at all. It's
1709 * possible the inode was fully unshared since it was originally tagged.
1710 */
1711 if (!xfs_inode_has_cow_data(ip)) {
1712 trace_xfs_inode_free_cowblocks_invalid(ip);
1713 xfs_inode_clear_cowblocks_tag(ip);
1714 return false;
1715 }
1716
1717 /*
1718 * If the mapping is dirty or under writeback we cannot touch the
1719 * CoW fork. Leave it alone if we're in the midst of a directio.
1720 */
1721 if ((VFS_I(ip)->i_state & I_DIRTY_PAGES) ||
1722 mapping_tagged(VFS_I(ip)->i_mapping, PAGECACHE_TAG_DIRTY) ||
1723 mapping_tagged(VFS_I(ip)->i_mapping, PAGECACHE_TAG_WRITEBACK) ||
1724 atomic_read(&VFS_I(ip)->i_dio_count))
1725 return false;
1726
1727 return true;
1728}
1729
1730/*
1731 * Automatic CoW Reservation Freeing
1732 *
1733 * These functions automatically garbage collect leftover CoW reservations
1734 * that were made on behalf of a cowextsize hint when we start to run out
1735 * of quota or when the reservations sit around for too long. If the file
1736 * has dirty pages or is undergoing writeback, its CoW reservations will
1737 * be retained.
1738 *
1739 * The actual garbage collection piggybacks off the same code that runs
1740 * the speculative EOF preallocation garbage collector.
1741 */
1742STATIC int
1743xfs_inode_free_cowblocks(
1744 struct xfs_inode *ip,
1745 int flags,
1746 void *args)
1747{
1748 struct xfs_eofblocks *eofb = args;
1749 int match;
1750 int ret = 0;
1751
1752 if (!xfs_prep_free_cowblocks(ip))
1753 return 0;
1754
1755 if (eofb) {
1756 if (eofb->eof_flags & XFS_EOF_FLAGS_UNION)
1757 match = xfs_inode_match_id_union(ip, eofb);
1758 else
1759 match = xfs_inode_match_id(ip, eofb);
1760 if (!match)
1761 return 0;
1762
1763 /* skip the inode if the file size is too small */
1764 if (eofb->eof_flags & XFS_EOF_FLAGS_MINFILESIZE &&
1765 XFS_ISIZE(ip) < eofb->eof_min_file_size)
1766 return 0;
1767 }
1768
1769 /* Free the CoW blocks */
1770 xfs_ilock(ip, XFS_IOLOCK_EXCL);
1771 xfs_ilock(ip, XFS_MMAPLOCK_EXCL);
1772
1773 /*
1774 * Check again, nobody else should be able to dirty blocks or change
1775 * the reflink iflag now that we have the first two locks held.
1776 */
1777 if (xfs_prep_free_cowblocks(ip))
1778 ret = xfs_reflink_cancel_cow_range(ip, 0, NULLFILEOFF, false);
1779
1780 xfs_iunlock(ip, XFS_MMAPLOCK_EXCL);
1781 xfs_iunlock(ip, XFS_IOLOCK_EXCL);
1782
1783 return ret;
1784}
1785
1786int
1787xfs_icache_free_cowblocks(
1788 struct xfs_mount *mp,
1789 struct xfs_eofblocks *eofb)
1790{
1791 return __xfs_icache_free_eofblocks(mp, eofb, xfs_inode_free_cowblocks,
1792 XFS_ICI_COWBLOCKS_TAG);
1793}
1794
1795int
1796xfs_inode_free_quota_cowblocks(
1797 struct xfs_inode *ip)
1798{
1799 return __xfs_inode_free_quota_eofblocks(ip, xfs_icache_free_cowblocks);
1800}
1801
1802void
1803xfs_inode_set_cowblocks_tag(
1804 xfs_inode_t *ip)
1805{
1806 trace_xfs_inode_set_cowblocks_tag(ip);
1807 return __xfs_inode_set_blocks_tag(ip, xfs_queue_cowblocks,
1808 trace_xfs_perag_set_cowblocks,
1809 XFS_ICI_COWBLOCKS_TAG);
1810}
1811
1812void
1813xfs_inode_clear_cowblocks_tag(
1814 xfs_inode_t *ip)
1815{
1816 trace_xfs_inode_clear_cowblocks_tag(ip);
1817 return __xfs_inode_clear_blocks_tag(ip,
1818 trace_xfs_perag_clear_cowblocks, XFS_ICI_COWBLOCKS_TAG);
1819}
1820
1821/* Disable post-EOF and CoW block auto-reclamation. */
1822void
1823xfs_stop_block_reaping(
1824 struct xfs_mount *mp)
1825{
1826 cancel_delayed_work_sync(&mp->m_eofblocks_work);
1827 cancel_delayed_work_sync(&mp->m_cowblocks_work);
1828}
1829
1830/* Enable post-EOF and CoW block auto-reclamation. */
1831void
1832xfs_start_block_reaping(
1833 struct xfs_mount *mp)
1834{
1835 xfs_queue_eofblocks(mp);
1836 xfs_queue_cowblocks(mp);
1837}