summaryrefslogtreecommitdiffstats
path: root/fs/xfs/linux-2.6/xfs_sync.c
blob: a608e72fa4054c3892bfc45b17e0343d21fd31ce (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
/*
 * Copyright (c) 2000-2005 Silicon Graphics, Inc.
 * All Rights Reserved.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as
 * published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it would be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write the Free Software Foundation,
 * Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 */
#include "xfs.h"
#include "xfs_fs.h"
#include "xfs_types.h"
#include "xfs_bit.h"
#include "xfs_log.h"
#include "xfs_inum.h"
#include "xfs_trans.h"
#include "xfs_sb.h"
#include "xfs_ag.h"
#include "xfs_dir2.h"
#include "xfs_dmapi.h"
#include "xfs_mount.h"
#include "xfs_bmap_btree.h"
#include "xfs_alloc_btree.h"
#include "xfs_ialloc_btree.h"
#include "xfs_btree.h"
#include "xfs_dir2_sf.h"
#include "xfs_attr_sf.h"
#include "xfs_inode.h"
#include "xfs_dinode.h"
#include "xfs_error.h"
#include "xfs_mru_cache.h"
#include "xfs_filestream.h"
#include "xfs_vnodeops.h"
#include "xfs_utils.h"
#include "xfs_buf_item.h"
#include "xfs_inode_item.h"
#include "xfs_rw.h"

#include <linux/kthread.h>
#include <linux/freezer.h>

/*
 * Sync all the inodes in the given AG according to the
 * direction given by the flags.
 */
STATIC int
xfs_sync_inodes_ag(
	xfs_mount_t	*mp,
	int		ag,
	int		flags)
{
	xfs_perag_t	*pag = &mp->m_perag[ag];
	int		nr_found;
	uint32_t	first_index = 0;
	int		error = 0;
	int		last_error = 0;
	int		fflag = XFS_B_ASYNC;

	if (flags & SYNC_DELWRI)
		fflag = XFS_B_DELWRI;
	if (flags & SYNC_WAIT)
		fflag = 0;		/* synchronous overrides all */

	do {
		struct inode	*inode;
		xfs_inode_t	*ip = NULL;
		int		lock_flags = XFS_ILOCK_SHARED;

		/*
		 * use a gang lookup to find the next inode in the tree
		 * as the tree is sparse and a gang lookup walks to find
		 * the number of objects requested.
		 */
		read_lock(&pag->pag_ici_lock);
		nr_found = radix_tree_gang_lookup(&pag->pag_ici_root,
				(void**)&ip, first_index, 1);

		if (!nr_found) {
			read_unlock(&pag->pag_ici_lock);
			break;
		}

		/*
		 * Update the index for the next lookup. Catch overflows
		 * into the next AG range which can occur if we have inodes
		 * in the last block of the AG and we are currently
		 * pointing to the last inode.
		 */
		first_index = XFS_INO_TO_AGINO(mp, ip->i_ino + 1);
		if (first_index < XFS_INO_TO_AGINO(mp, ip->i_ino)) {
			read_unlock(&pag->pag_ici_lock);
			break;
		}

		/* nothing to sync during shutdown */
		if (XFS_FORCED_SHUTDOWN(mp)) {
			read_unlock(&pag->pag_ici_lock);
			return 0;
		}

		/*
		 * If we can't get a reference on the inode, it must be
		 * in reclaim. Leave it for the reclaim code to flush.
		 */
		inode = VFS_I(ip);
		if (!igrab(inode)) {
			read_unlock(&pag->pag_ici_lock);
			continue;
		}
		read_unlock(&pag->pag_ici_lock);

		/* avoid new or bad inodes */
		if (is_bad_inode(inode) ||
		    xfs_iflags_test(ip, XFS_INEW)) {
			IRELE(ip);
			continue;
		}

		/*
		 * If we have to flush data or wait for I/O completion
		 * we need to hold the iolock.
		 */
		if ((flags & SYNC_DELWRI) && VN_DIRTY(inode)) {
			xfs_ilock(ip, XFS_IOLOCK_SHARED);
			lock_flags |= XFS_IOLOCK_SHARED;
			error = xfs_flush_pages(ip, 0, -1, fflag, FI_NONE);
			if (flags & SYNC_IOWAIT)
				xfs_ioend_wait(ip);
		}
		xfs_ilock(ip, XFS_ILOCK_SHARED);

		if ((flags & SYNC_ATTR) && !xfs_inode_clean(ip)) {
			if (flags & SYNC_WAIT) {
				xfs_iflock(ip);
				if (!xfs_inode_clean(ip))
					error = xfs_iflush(ip, XFS_IFLUSH_SYNC);
				else
					xfs_ifunlock(ip);
			} else if (xfs_iflock_nowait(ip)) {
				if (!xfs_inode_clean(ip))
					error = xfs_iflush(ip, XFS_IFLUSH_DELWRI);
				else
					xfs_ifunlock(ip);
			}
		}
		xfs_iput(ip, lock_flags);

		if (error)
			last_error = error;
		/*
		 * bail out if the filesystem is corrupted.
		 */
		if (error == EFSCORRUPTED)
			return XFS_ERROR(error);

	} while (nr_found);

	return last_error;
}

int
xfs_sync_inodes(
	xfs_mount_t	*mp,
	int		flags)
{
	int		error;
	int		last_error;
	int		i;
	int		lflags = XFS_LOG_FORCE;

	if (mp->m_flags & XFS_MOUNT_RDONLY)
		return 0;
	error = 0;
	last_error = 0;

	if (flags & SYNC_WAIT)
		lflags |= XFS_LOG_SYNC;

	for (i = 0; i < mp->m_sb.sb_agcount; i++) {
		if (!mp->m_perag[i].pag_ici_init)
			continue;
		error = xfs_sync_inodes_ag(mp, i, flags);
		if (error)
			last_error = error;
		if (error == EFSCORRUPTED)
			break;
	}
	if (flags & SYNC_DELWRI)
		xfs_log_force(mp, 0, lflags);

	return XFS_ERROR(last_error);
}

STATIC int
xfs_commit_dummy_trans(
	struct xfs_mount	*mp,
	uint			log_flags)
{
	struct xfs_inode	*ip = mp->m_rootip;
	struct xfs_trans	*tp;
	int			error;

	/*
	 * Put a dummy transaction in the log to tell recovery
	 * that all others are OK.
	 */
	tp = xfs_trans_alloc(mp, XFS_TRANS_DUMMY1);
	error = xfs_trans_reserve(tp, 0, XFS_ICHANGE_LOG_RES(mp), 0, 0, 0);
	if (error) {
		xfs_trans_cancel(tp, 0);
		return error;
	}

	xfs_ilock(ip, XFS_ILOCK_EXCL);

	xfs_trans_ijoin(tp, ip, XFS_ILOCK_EXCL);
	xfs_trans_ihold(tp, ip);
	xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
	/* XXX(hch): ignoring the error here.. */
	error = xfs_trans_commit(tp, 0);

	xfs_iunlock(ip, XFS_ILOCK_EXCL);

	xfs_log_force(mp, 0, log_flags);
	return 0;
}

int
xfs_sync_fsdata(
	struct xfs_mount	*mp,
	int			flags)
{
	struct xfs_buf		*bp;
	struct xfs_buf_log_item	*bip;
	int			error = 0;

	/*
	 * If this is xfssyncd() then only sync the superblock if we can
	 * lock it without sleeping and it is not pinned.
	 */
	if (flags & SYNC_BDFLUSH) {
		ASSERT(!(flags & SYNC_WAIT));

		bp = xfs_getsb(mp, XFS_BUF_TRYLOCK);
		if (!bp)
			goto out;

		bip = XFS_BUF_FSPRIVATE(bp, struct xfs_buf_log_item *);
		if (!bip || !xfs_buf_item_dirty(bip) || XFS_BUF_ISPINNED(bp))
			goto out_brelse;
	} else {
		bp = xfs_getsb(mp, 0);

		/*
		 * If the buffer is pinned then push on the log so we won't
		 * get stuck waiting in the write for someone, maybe
		 * ourselves, to flush the log.
		 *
		 * Even though we just pushed the log above, we did not have
		 * the superblock buffer locked at that point so it can
		 * become pinned in between there and here.
		 */
		if (XFS_BUF_ISPINNED(bp))
			xfs_log_force(mp, 0, XFS_LOG_FORCE);
	}


	if (flags & SYNC_WAIT)
		XFS_BUF_UNASYNC(bp);
	else
		XFS_BUF_ASYNC(bp);

	return xfs_bwrite(mp, bp);

 out_brelse:
	xfs_buf_relse(bp);
 out:
	return error;
}

/*
 * When remounting a filesystem read-only or freezing the filesystem, we have
 * two phases to execute. This first phase is syncing the data before we
 * quiesce the filesystem, and the second is flushing all the inodes out after
 * we've waited for all the transactions created by the first phase to
 * complete. The second phase ensures that the inodes are written to their
 * location on disk rather than just existing in transactions in the log. This
 * means after a quiesce there is no log replay required to write the inodes to
 * disk (this is the main difference between a sync and a quiesce).
 */
/*
 * First stage of freeze - no writers will make progress now we are here,
 * so we flush delwri and delalloc buffers here, then wait for all I/O to
 * complete.  Data is frozen at that point. Metadata is not frozen,
 * transactions can still occur here so don't bother flushing the buftarg
 * because it'll just get dirty again.
 */
int
xfs_quiesce_data(
	struct xfs_mount	*mp)
{
	int error;

	/* push non-blocking */
	xfs_sync_inodes(mp, SYNC_DELWRI|SYNC_BDFLUSH);
	XFS_QM_DQSYNC(mp, SYNC_BDFLUSH);
	xfs_filestream_flush(mp);

	/* push and block */
	xfs_sync_inodes(mp, SYNC_DELWRI|SYNC_WAIT|SYNC_IOWAIT);
	XFS_QM_DQSYNC(mp, SYNC_WAIT);

	/* write superblock and hoover up shutdown errors */
	error = xfs_sync_fsdata(mp, 0);

	/* flush data-only devices */
	if (mp->m_rtdev_targp)
		XFS_bflush(mp->m_rtdev_targp);

	return error;
}

STATIC void
xfs_quiesce_fs(
	struct xfs_mount	*mp)
{
	int	count = 0, pincount;

	xfs_flush_buftarg(mp->m_ddev_targp, 0);
	xfs_reclaim_inodes(mp, 0, XFS_IFLUSH_DELWRI_ELSE_ASYNC);

	/*
	 * This loop must run at least twice.  The first instance of the loop
	 * will flush most meta data but that will generate more meta data
	 * (typically directory updates).  Which then must be flushed and
	 * logged before we can write the unmount record.
	 */
	do {
		xfs_sync_inodes(mp, SYNC_ATTR|SYNC_WAIT);
		pincount = xfs_flush_buftarg(mp->m_ddev_targp, 1);
		if (!pincount) {
			delay(50);
			count++;
		}
	} while (count < 2);
}

/*
 * Second stage of a quiesce. The data is already synced, now we have to take
 * care of the metadata. New transactions are already blocked, so we need to
 * wait for any remaining transactions to drain out before proceding.
 */
void
xfs_quiesce_attr(
	struct xfs_mount	*mp)
{
	int	error = 0;

	/* wait for all modifications to complete */
	while (atomic_read(&mp->m_active_trans) > 0)
		delay(100);

	/* flush inodes and push all remaining buffers out to disk */
	xfs_quiesce_fs(mp);

	/*
	 * Just warn here till VFS can correctly support
	 * read-only remount without racing.
	 */
	WARN_ON(atomic_read(&mp->m_active_trans) != 0);

	/* Push the superblock and write an unmount record */
	error = xfs_log_sbcount(mp, 1);
	if (error)
		xfs_fs_cmn_err(CE_WARN, mp,
				"xfs_attr_quiesce: failed to log sb changes. "
				"Frozen image may not be consistent.");
	xfs_log_unmount_write(mp);
	xfs_unmountfs_writesb(mp);
}

/*
 * Enqueue a work item to be picked up by the vfs xfssyncd thread.
 * Doing this has two advantages:
 * - It saves on stack space, which is tight in certain situations
 * - It can be used (with care) as a mechanism to avoid deadlocks.
 * Flushing while allocating in a full filesystem requires both.
 */
STATIC void
xfs_syncd_queue_work(
	struct xfs_mount *mp,
	void		*data,
	void		(*syncer)(struct xfs_mount *, void *))
{
	struct bhv_vfs_sync_work *work;

	work = kmem_alloc(sizeof(struct bhv_vfs_sync_work), KM_SLEEP);
	INIT_LIST_HEAD(&work->w_list);
	work->w_syncer = syncer;
	work->w_data = data;
	work->w_mount = mp;
	spin_lock(&mp->m_sync_lock);
	list_add_tail(&work->w_list, &mp->m_sync_list);
	spin_unlock(&mp->m_sync_lock);
	wake_up_process(mp->m_sync_task);
}

/*
 * Flush delayed allocate data, attempting to free up reserved space
 * from existing allocations.  At this point a new allocation attempt
 * has failed with ENOSPC and we are in the process of scratching our
 * heads, looking about for more room...
 */
STATIC void
xfs_flush_inode_work(
	struct xfs_mount *mp,
	void		*arg)
{
	struct inode	*inode = arg;
	filemap_flush(inode->i_mapping);
	iput(inode);
}

void
xfs_flush_inode(
	xfs_inode_t	*ip)
{
	struct inode	*inode = VFS_I(ip);

	igrab(inode);
	xfs_syncd_queue_work(ip->i_mount, inode, xfs_flush_inode_work);
	delay(msecs_to_jiffies(500));
}

/*
 * This is the "bigger hammer" version of xfs_flush_inode_work...
 * (IOW, "If at first you don't succeed, use a Bigger Hammer").
 */
STATIC void
xfs_flush_device_work(
	struct xfs_mount *mp,
	void		*arg)
{
	struct inode	*inode = arg;
	sync_blockdev(mp->m_super->s_bdev);
	iput(inode);
}

void
xfs_flush_device(
	xfs_inode_t	*ip)
{
	struct inode	*inode = VFS_I(ip);

	igrab(inode);
	xfs_syncd_queue_work(ip->i_mount, inode, xfs_flush_device_work);
	delay(msecs_to_jiffies(500));
	xfs_log_force(ip->i_mount, (xfs_lsn_t)0, XFS_LOG_FORCE|XFS_LOG_SYNC);
}

/*
 * Every sync period we need to unpin all items, reclaim inodes, sync
 * quota and write out the superblock. We might need to cover the log
 * to indicate it is idle.
 */
STATIC void
xfs_sync_worker(
	struct xfs_mount *mp,
	void		*unused)
{
	int		error;

	if (!(mp->m_flags & XFS_MOUNT_RDONLY)) {
		xfs_log_force(mp, (xfs_lsn_t)0, XFS_LOG_FORCE);
		xfs_reclaim_inodes(mp, 0, XFS_IFLUSH_DELWRI_ELSE_ASYNC);
		/* dgc: errors ignored here */
		error = XFS_QM_DQSYNC(mp, SYNC_BDFLUSH);
		error = xfs_sync_fsdata(mp, SYNC_BDFLUSH);
		if (xfs_log_need_covered(mp))
			error = xfs_commit_dummy_trans(mp, XFS_LOG_FORCE);
	}
	mp->m_sync_seq++;
	wake_up(&mp->m_wait_single_sync_task);
}

STATIC int
xfssyncd(
	void			*arg)
{
	struct xfs_mount	*mp = arg;
	long			timeleft;
	bhv_vfs_sync_work_t	*work, *n;
	LIST_HEAD		(tmp);

	set_freezable();
	timeleft = xfs_syncd_centisecs * msecs_to_jiffies(10);
	for (;;) {
		timeleft = schedule_timeout_interruptible(timeleft);
		/* swsusp */
		try_to_freeze();
		if (kthread_should_stop() && list_empty(&mp->m_sync_list))
			break;

		spin_lock(&mp->m_sync_lock);
		/*
		 * We can get woken by laptop mode, to do a sync -
		 * that's the (only!) case where the list would be
		 * empty with time remaining.
		 */
		if (!timeleft || list_empty(&mp->m_sync_list)) {
			if (!timeleft)
				timeleft = xfs_syncd_centisecs *
							msecs_to_jiffies(10);
			INIT_LIST_HEAD(&mp->m_sync_work.w_list);
			list_add_tail(&mp->m_sync_work.w_list,
					&mp->m_sync_list);
		}
		list_for_each_entry_safe(work, n, &mp->m_sync_list, w_list)
			list_move(&work->w_list, &tmp);
		spin_unlock(&mp->m_sync_lock);

		list_for_each_entry_safe(work, n, &tmp, w_list) {
			(*work->w_syncer)(mp, work->w_data);
			list_del(&work->w_list);
			if (work == &mp->m_sync_work)
				continue;
			kmem_free(work);
		}
	}

	return 0;
}

int
xfs_syncd_init(
	struct xfs_mount	*mp)
{
	mp->m_sync_work.w_syncer = xfs_sync_worker;
	mp->m_sync_work.w_mount = mp;
	mp->m_sync_task = kthread_run(xfssyncd, mp, "xfssyncd");
	if (IS_ERR(mp->m_sync_task))
		return -PTR_ERR(mp->m_sync_task);
	return 0;
}

void
xfs_syncd_stop(
	struct xfs_mount	*mp)
{
	kthread_stop(mp->m_sync_task);
}

int
xfs_reclaim_inode(
	xfs_inode_t	*ip,
	int		locked,
	int		sync_mode)
{
	xfs_perag_t	*pag = xfs_get_perag(ip->i_mount, ip->i_ino);

	/* The hash lock here protects a thread in xfs_iget_core from
	 * racing with us on linking the inode back with a vnode.
	 * Once we have the XFS_IRECLAIM flag set it will not touch
	 * us.
	 */
	write_lock(&pag->pag_ici_lock);
	spin_lock(&ip->i_flags_lock);
	if (__xfs_iflags_test(ip, XFS_IRECLAIM) ||
	    !__xfs_iflags_test(ip, XFS_IRECLAIMABLE)) {
		spin_unlock(&ip->i_flags_lock);
		write_unlock(&pag->pag_ici_lock);
		if (locked) {
			xfs_ifunlock(ip);
			xfs_iunlock(ip, XFS_ILOCK_EXCL);
		}
		return 1;
	}
	__xfs_iflags_set(ip, XFS_IRECLAIM);
	spin_unlock(&ip->i_flags_lock);
	write_unlock(&pag->pag_ici_lock);
	xfs_put_perag(ip->i_mount, pag);

	/*
	 * If the inode is still dirty, then flush it out.  If the inode
	 * is not in the AIL, then it will be OK to flush it delwri as
	 * long as xfs_iflush() does not keep any references to the inode.
	 * We leave that decision up to xfs_iflush() since it has the
	 * knowledge of whether it's OK to simply do a delwri flush of
	 * the inode or whether we need to wait until the inode is
	 * pulled from the AIL.
	 * We get the flush lock regardless, though, just to make sure
	 * we don't free it while it is being flushed.
	 */
	if (!locked) {
		xfs_ilock(ip, XFS_ILOCK_EXCL);
		xfs_iflock(ip);
	}

	/*
	 * In the case of a forced shutdown we rely on xfs_iflush() to
	 * wait for the inode to be unpinned before returning an error.
	 */
	if (!is_bad_inode(VFS_I(ip)) && xfs_iflush(ip, sync_mode) == 0) {
		/* synchronize with xfs_iflush_done */
		xfs_iflock(ip);
		xfs_ifunlock(ip);
	}

	xfs_iunlock(ip, XFS_ILOCK_EXCL);
	xfs_ireclaim(ip);
	return 0;
}

/*
 * We set the inode flag atomically with the radix tree tag.
 * Once we get tag lookups on the radix tree, this inode flag
 * can go away.
 */
void
xfs_inode_set_reclaim_tag(
	xfs_inode_t	*ip)
{
	xfs_mount_t	*mp = ip->i_mount;
	xfs_perag_t	*pag = xfs_get_perag(mp, ip->i_ino);

	read_lock(&pag->pag_ici_lock);
	spin_lock(&ip->i_flags_lock);
	radix_tree_tag_set(&pag->pag_ici_root,
			XFS_INO_TO_AGINO(mp, ip->i_ino), XFS_ICI_RECLAIM_TAG);
	__xfs_iflags_set(ip, XFS_IRECLAIMABLE);
	spin_unlock(&ip->i_flags_lock);
	read_unlock(&pag->pag_ici_lock);
	xfs_put_perag(mp, pag);
}

void
__xfs_inode_clear_reclaim_tag(
	xfs_mount_t	*mp,
	xfs_perag_t	*pag,
	xfs_inode_t	*ip)
{
	radix_tree_tag_clear(&pag->pag_ici_root,
			XFS_INO_TO_AGINO(mp, ip->i_ino), XFS_ICI_RECLAIM_TAG);
}

void
xfs_inode_clear_reclaim_tag(
	xfs_inode_t	*ip)
{
	xfs_mount_t	*mp = ip->i_mount;
	xfs_perag_t	*pag = xfs_get_perag(mp, ip->i_ino);

	read_lock(&pag->pag_ici_lock);
	spin_lock(&ip->i_flags_lock);
	__xfs_inode_clear_reclaim_tag(mp, pag, ip);
	spin_unlock(&ip->i_flags_lock);
	read_unlock(&pag->pag_ici_lock);
	xfs_put_perag(mp, pag);
}


STATIC void
xfs_reclaim_inodes_ag(
	xfs_mount_t	*mp,
	int		ag,
	int		noblock,
	int		mode)
{
	xfs_inode_t	*ip = NULL;
	xfs_perag_t	*pag = &mp->m_perag[ag];
	int		nr_found;
	uint32_t	first_index;
	int		skipped;

restart:
	first_index = 0;
	skipped = 0;
	do {
		/*
		 * use a gang lookup to find the next inode in the tree
		 * as the tree is sparse and a gang lookup walks to find
		 * the number of objects requested.
		 */
		read_lock(&pag->pag_ici_lock);
		nr_found = radix_tree_gang_lookup_tag(&pag->pag_ici_root,
					(void**)&ip, first_index, 1,
					XFS_ICI_RECLAIM_TAG);

		if (!nr_found) {
			read_unlock(&pag->pag_ici_lock);
			break;
		}

		/*
		 * Update the index for the next lookup. Catch overflows
		 * into the next AG range which can occur if we have inodes
		 * in the last block of the AG and we are currently
		 * pointing to the last inode.
		 */
		first_index = XFS_INO_TO_AGINO(mp, ip->i_ino + 1);
		if (first_index < XFS_INO_TO_AGINO(mp, ip->i_ino)) {
			read_unlock(&pag->pag_ici_lock);
			break;
		}

		/* ignore if already under reclaim */
		if (xfs_iflags_test(ip, XFS_IRECLAIM)) {
			read_unlock(&pag->pag_ici_lock);
			continue;
		}

		if (noblock) {
			if (!xfs_ilock_nowait(ip, XFS_ILOCK_EXCL)) {
				read_unlock(&pag->pag_ici_lock);
				continue;
			}
			if (xfs_ipincount(ip) ||
			    !xfs_iflock_nowait(ip)) {
				xfs_iunlock(ip, XFS_ILOCK_EXCL);
				read_unlock(&pag->pag_ici_lock);
				continue;
			}
		}
		read_unlock(&pag->pag_ici_lock);

		/*
		 * hmmm - this is an inode already in reclaim. Do
		 * we even bother catching it here?
		 */
		if (xfs_reclaim_inode(ip, noblock, mode))
			skipped++;
	} while (nr_found);

	if (skipped) {
		delay(1);
		goto restart;
	}
	return;

}

int
xfs_reclaim_inodes(
	xfs_mount_t	*mp,
	int		 noblock,
	int		mode)
{
	int		i;

	for (i = 0; i < mp->m_sb.sb_agcount; i++) {
		if (!mp->m_perag[i].pag_ici_init)
			continue;
		xfs_reclaim_inodes_ag(mp, i, noblock, mode);
	}
	return 0;
}