aboutsummaryrefslogtreecommitdiffstats
path: root/fs/xfs/xfs_iget.c
blob: 488836e204a3493f968a9e473ce1b00eca67823d (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
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
/*
 * 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_dir2_sf.h"
#include "xfs_attr_sf.h"
#include "xfs_dinode.h"
#include "xfs_inode.h"
#include "xfs_btree.h"
#include "xfs_ialloc.h"
#include "xfs_quota.h"
#include "xfs_utils.h"

/*
 * Look up an inode by number in the given file system.
 * The inode is looked up in the cache held in each AG.
 * If the inode is found in the cache, attach it to the provided
 * vnode.
 *
 * If it is not in core, read it in from the file system's device,
 * add it to the cache and attach the provided vnode.
 *
 * The inode is locked according to the value of the lock_flags parameter.
 * This flag parameter indicates how and if the inode's IO lock and inode lock
 * should be taken.
 *
 * mp -- the mount point structure for the current file system.  It points
 *       to the inode hash table.
 * tp -- a pointer to the current transaction if there is one.  This is
 *       simply passed through to the xfs_iread() call.
 * ino -- the number of the inode desired.  This is the unique identifier
 *        within the file system for the inode being requested.
 * lock_flags -- flags indicating how to lock the inode.  See the comment
 *		 for xfs_ilock() for a list of valid values.
 * bno -- the block number starting the buffer containing the inode,
 *	  if known (as by bulkstat), else 0.
 */
STATIC int
xfs_iget_core(
	bhv_vnode_t	*vp,
	xfs_mount_t	*mp,
	xfs_trans_t	*tp,
	xfs_ino_t	ino,
	uint		flags,
	uint		lock_flags,
	xfs_inode_t	**ipp,
	xfs_daddr_t	bno)
{
	xfs_inode_t	*ip;
	xfs_inode_t	*iq;
	bhv_vnode_t	*inode_vp;
	int		error;
	xfs_icluster_t	*icl, *new_icl = NULL;
	unsigned long	first_index, mask;
	xfs_perag_t	*pag;
	xfs_agino_t	agino;

	/* the radix tree exists only in inode capable AGs */
	if (XFS_INO_TO_AGNO(mp, ino) >= mp->m_maxagi)
		return EINVAL;

	/* get the perag structure and ensure that it's inode capable */
	pag = xfs_get_perag(mp, ino);
	if (!pag->pagi_inodeok)
		return EINVAL;
	ASSERT(pag->pag_ici_init);
	agino = XFS_INO_TO_AGINO(mp, ino);

again:
	read_lock(&pag->pag_ici_lock);
	ip = radix_tree_lookup(&pag->pag_ici_root, agino);

	if (ip != NULL) {
		/*
		 * If INEW is set this inode is being set up
		 * we need to pause and try again.
		 */
		if (xfs_iflags_test(ip, XFS_INEW)) {
			read_unlock(&pag->pag_ici_lock);
			delay(1);
			XFS_STATS_INC(xs_ig_frecycle);

			goto again;
		}

		inode_vp = XFS_ITOV_NULL(ip);
		if (inode_vp == NULL) {
			/*
			 * If IRECLAIM is set this inode is
			 * on its way out of the system,
			 * we need to pause and try again.
			 */
			if (xfs_iflags_test(ip, XFS_IRECLAIM)) {
				read_unlock(&pag->pag_ici_lock);
				delay(1);
				XFS_STATS_INC(xs_ig_frecycle);

				goto again;
			}
			ASSERT(xfs_iflags_test(ip, XFS_IRECLAIMABLE));

			/*
			 * If lookup is racing with unlink, then we
			 * should return an error immediately so we
			 * don't remove it from the reclaim list and
			 * potentially leak the inode.
			 */
			if ((ip->i_d.di_mode == 0) &&
			    !(flags & XFS_IGET_CREATE)) {
				read_unlock(&pag->pag_ici_lock);
				xfs_put_perag(mp, pag);
				return ENOENT;
			}

			/*
			 * There may be transactions sitting in the
			 * incore log buffers or being flushed to disk
			 * at this time.  We can't clear the
			 * XFS_IRECLAIMABLE flag until these
			 * transactions have hit the disk, otherwise we
			 * will void the guarantee the flag provides
			 * xfs_iunpin()
			 */
			if (xfs_ipincount(ip)) {
				read_unlock(&pag->pag_ici_lock);
				xfs_log_force(mp, 0,
					XFS_LOG_FORCE|XFS_LOG_SYNC);
				XFS_STATS_INC(xs_ig_frecycle);
				goto again;
			}

			vn_trace_exit(ip, "xfs_iget.alloc",
				(inst_t *)__return_address);

			XFS_STATS_INC(xs_ig_found);

			xfs_iflags_clear(ip, XFS_IRECLAIMABLE);
			read_unlock(&pag->pag_ici_lock);

			XFS_MOUNT_ILOCK(mp);
			list_del_init(&ip->i_reclaim);
			XFS_MOUNT_IUNLOCK(mp);

			goto finish_inode;

		} else if (vp != inode_vp) {
			struct inode *inode = vn_to_inode(inode_vp);

			/* The inode is being torn down, pause and
			 * try again.
			 */
			if (inode->i_state & (I_FREEING | I_CLEAR)) {
				read_unlock(&pag->pag_ici_lock);
				delay(1);
				XFS_STATS_INC(xs_ig_frecycle);

				goto again;
			}
/* Chances are the other vnode (the one in the inode) is being torn
* down right now, and we landed on top of it. Question is, what do
* we do? Unhook the old inode and hook up the new one?
*/
			cmn_err(CE_PANIC,
		"xfs_iget_core: ambiguous vns: vp/0x%p, invp/0x%p",
					inode_vp, vp);
		}

		/*
		 * Inode cache hit
		 */
		read_unlock(&pag->pag_ici_lock);
		XFS_STATS_INC(xs_ig_found);

finish_inode:
		if (ip->i_d.di_mode == 0) {
			if (!(flags & XFS_IGET_CREATE)) {
				xfs_put_perag(mp, pag);
				return ENOENT;
			}
			xfs_iocore_inode_reinit(ip);
		}

		if (lock_flags != 0)
			xfs_ilock(ip, lock_flags);

		xfs_iflags_clear(ip, XFS_ISTALE);
		vn_trace_exit(ip, "xfs_iget.found",
					(inst_t *)__return_address);
		goto return_ip;
	}

	/*
	 * Inode cache miss
	 */
	read_unlock(&pag->pag_ici_lock);
	XFS_STATS_INC(xs_ig_missed);

	/*
	 * Read the disk inode attributes into a new inode structure and get
	 * a new vnode for it. This should also initialize i_ino and i_mount.
	 */
	error = xfs_iread(mp, tp, ino, &ip, bno,
			  (flags & XFS_IGET_BULKSTAT) ? XFS_IMAP_BULKSTAT : 0);
	if (error) {
		xfs_put_perag(mp, pag);
		return error;
	}

	vn_trace_exit(ip, "xfs_iget.alloc", (inst_t *)__return_address);

	xfs_inode_lock_init(ip, vp);
	xfs_iocore_inode_init(ip);
	if (lock_flags)
		xfs_ilock(ip, lock_flags);

	if ((ip->i_d.di_mode == 0) && !(flags & XFS_IGET_CREATE)) {
		xfs_idestroy(ip);
		xfs_put_perag(mp, pag);
		return ENOENT;
	}

	/*
	 * This is a bit messy - we preallocate everything we _might_
	 * need before we pick up the ici lock. That way we don't have to
	 * juggle locks and go all the way back to the start.
	 */
	new_icl = kmem_zone_alloc(xfs_icluster_zone, KM_SLEEP);
	if (radix_tree_preload(GFP_KERNEL)) {
		delay(1);
		goto again;
	}
	mask = ~(((XFS_INODE_CLUSTER_SIZE(mp) >> mp->m_sb.sb_inodelog)) - 1);
	first_index = agino & mask;
	write_lock(&pag->pag_ici_lock);

	/*
	 * Find the cluster if it exists
	 */
	icl = NULL;
	if (radix_tree_gang_lookup(&pag->pag_ici_root, (void**)&iq,
							first_index, 1)) {
		if ((iq->i_ino & mask) == first_index)
			icl = iq->i_cluster;
	}

	/*
	 * insert the new inode
	 */
	error = radix_tree_insert(&pag->pag_ici_root, agino, ip);
	if (unlikely(error)) {
		BUG_ON(error != -EEXIST);
		write_unlock(&pag->pag_ici_lock);
		radix_tree_preload_end();
		xfs_idestroy(ip);
		XFS_STATS_INC(xs_ig_dup);
		goto again;
	}

	/*
	 * These values _must_ be set before releasing ihlock!
	 */
	ip->i_udquot = ip->i_gdquot = NULL;
	xfs_iflags_set(ip, XFS_INEW);

	ASSERT(ip->i_cluster == NULL);

	if (!icl) {
		spin_lock_init(&new_icl->icl_lock);
		INIT_HLIST_HEAD(&new_icl->icl_inodes);
		icl = new_icl;
		new_icl = NULL;
	} else {
		ASSERT(!hlist_empty(&icl->icl_inodes));
	}
	spin_lock(&icl->icl_lock);
	hlist_add_head(&ip->i_cnode, &icl->icl_inodes);
	ip->i_cluster = icl;
	spin_unlock(&icl->icl_lock);

	write_unlock(&pag->pag_ici_lock);
	radix_tree_preload_end();
	if (new_icl)
		kmem_zone_free(xfs_icluster_zone, new_icl);

	/*
	 * Link ip to its mount and thread it on the mount's inode list.
	 */
	XFS_MOUNT_ILOCK(mp);
	if ((iq = mp->m_inodes)) {
		ASSERT(iq->i_mprev->i_mnext == iq);
		ip->i_mprev = iq->i_mprev;
		iq->i_mprev->i_mnext = ip;
		iq->i_mprev = ip;
		ip->i_mnext = iq;
	} else {
		ip->i_mnext = ip;
		ip->i_mprev = ip;
	}
	mp->m_inodes = ip;

	XFS_MOUNT_IUNLOCK(mp);
	xfs_put_perag(mp, pag);

 return_ip:
	ASSERT(ip->i_df.if_ext_max ==
	       XFS_IFORK_DSIZE(ip) / sizeof(xfs_bmbt_rec_t));

	ASSERT(((ip->i_d.di_flags & XFS_DIFLAG_REALTIME) != 0) ==
	       ((ip->i_iocore.io_flags & XFS_IOCORE_RT) != 0));

	xfs_iflags_set(ip, XFS_IMODIFIED);
	*ipp = ip;

	/*
	 * If we have a real type for an on-disk inode, we can set ops(&unlock)
	 * now.	 If it's a new inode being created, xfs_ialloc will handle it.
	 */
	xfs_initialize_vnode(mp, vp, ip);
	return 0;
}


/*
 * The 'normal' internal xfs_iget, if needed it will
 * 'allocate', or 'get', the vnode.
 */
int
xfs_iget(
	xfs_mount_t	*mp,
	xfs_trans_t	*tp,
	xfs_ino_t	ino,
	uint		flags,
	uint		lock_flags,
	xfs_inode_t	**ipp,
	xfs_daddr_t	bno)
{
	struct inode	*inode;
	bhv_vnode_t	*vp = NULL;
	int		error;

	XFS_STATS_INC(xs_ig_attempts);

retry:
	inode = iget_locked(mp->m_super, ino);
	if (inode) {
		xfs_inode_t	*ip;

		vp = vn_from_inode(inode);
		if (inode->i_state & I_NEW) {
			vn_initialize(inode);
			error = xfs_iget_core(vp, mp, tp, ino, flags,
					lock_flags, ipp, bno);
			if (error) {
				vn_mark_bad(vp);
				if (inode->i_state & I_NEW)
					unlock_new_inode(inode);
				iput(inode);
			}
		} else {
			/*
			 * If the inode is not fully constructed due to
			 * filehandle mismatches wait for the inode to go
			 * away and try again.
			 *
			 * iget_locked will call __wait_on_freeing_inode
			 * to wait for the inode to go away.
			 */
			if (is_bad_inode(inode) ||
			    ((ip = xfs_vtoi(vp)) == NULL)) {
				iput(inode);
				delay(1);
				goto retry;
			}

			if (lock_flags != 0)
				xfs_ilock(ip, lock_flags);
			XFS_STATS_INC(xs_ig_found);
			*ipp = ip;
			error = 0;
		}
	} else
		error = ENOMEM;	/* If we got no inode we are out of memory */

	return error;
}

/*
 * Do the setup for the various locks within the incore inode.
 */
void
xfs_inode_lock_init(
	xfs_inode_t	*ip,
	bhv_vnode_t	*vp)
{
	mrlock_init(&ip->i_lock, MRLOCK_ALLOW_EQUAL_PRI|MRLOCK_BARRIER,
		     "xfsino", ip->i_ino);
	mrlock_init(&ip->i_iolock, MRLOCK_BARRIER, "xfsio", ip->i_ino);
	init_waitqueue_head(&ip->i_ipin_wait);
	atomic_set(&ip->i_pincount, 0);
	initnsema(&ip->i_flock, 1, "xfsfino");
}

/*
 * Look for the inode corresponding to the given ino in the hash table.
 * If it is there and its i_transp pointer matches tp, return it.
 * Otherwise, return NULL.
 */
xfs_inode_t *
xfs_inode_incore(xfs_mount_t	*mp,
		 xfs_ino_t	ino,
		 xfs_trans_t	*tp)
{
	xfs_inode_t	*ip;
	xfs_perag_t	*pag;

	pag = xfs_get_perag(mp, ino);
	read_lock(&pag->pag_ici_lock);
	ip = radix_tree_lookup(&pag->pag_ici_root, XFS_INO_TO_AGINO(mp, ino));
	read_unlock(&pag->pag_ici_lock);
	xfs_put_perag(mp, pag);

	/* the returned inode must match the transaction */
	if (ip && (ip->i_transp != tp))
		return NULL;
	return ip;
}

/*
 * Decrement reference count of an inode structure and unlock it.
 *
 * ip -- the inode being released
 * lock_flags -- this parameter indicates the inode's locks to be
 *       to be released.  See the comment on xfs_iunlock() for a list
 *	 of valid values.
 */
void
xfs_iput(xfs_inode_t	*ip,
	 uint		lock_flags)
{
	bhv_vnode_t	*vp = XFS_ITOV(ip);

	vn_trace_entry(ip, "xfs_iput", (inst_t *)__return_address);
	xfs_iunlock(ip, lock_flags);
	VN_RELE(vp);
}

/*
 * Special iput for brand-new inodes that are still locked
 */
void
xfs_iput_new(xfs_inode_t	*ip,
	     uint		lock_flags)
{
	bhv_vnode_t	*vp = XFS_ITOV(ip);
	struct inode	*inode = vn_to_inode(vp);

	vn_trace_entry(ip, "xfs_iput_new", (inst_t *)__return_address);

	if ((ip->i_d.di_mode == 0)) {
		ASSERT(!xfs_iflags_test(ip, XFS_IRECLAIMABLE));
		vn_mark_bad(vp);
	}
	if (inode->i_state & I_NEW)
		unlock_new_inode(inode);
	if (lock_flags)
		xfs_iunlock(ip, lock_flags);
	VN_RELE(vp);
}


/*
 * This routine embodies the part of the reclaim code that pulls
 * the inode from the inode hash table and the mount structure's
 * inode list.
 * This should only be called from xfs_reclaim().
 */
void
xfs_ireclaim(xfs_inode_t *ip)
{
	bhv_vnode_t	*vp;

	/*
	 * Remove from old hash list and mount list.
	 */
	XFS_STATS_INC(xs_ig_reclaims);

	xfs_iextract(ip);

	/*
	 * Here we do a spurious inode lock in order to coordinate with
	 * xfs_sync().  This is because xfs_sync() references the inodes
	 * in the mount list without taking references on the corresponding
	 * vnodes.  We make that OK here by ensuring that we wait until
	 * the inode is unlocked in xfs_sync() before we go ahead and
	 * free it.  We get both the regular lock and the io lock because
	 * the xfs_sync() code may need to drop the regular one but will
	 * still hold the io lock.
	 */
	xfs_ilock(ip, XFS_ILOCK_EXCL | XFS_IOLOCK_EXCL);

	/*
	 * Release dquots (and their references) if any. An inode may escape
	 * xfs_inactive and get here via vn_alloc->vn_reclaim path.
	 */
	XFS_QM_DQDETACH(ip->i_mount, ip);

	/*
	 * Pull our behavior descriptor from the vnode chain.
	 */
	vp = XFS_ITOV_NULL(ip);
	if (vp) {
		vn_to_inode(vp)->i_private = NULL;
		ip->i_vnode = NULL;
	}

	/*
	 * Free all memory associated with the inode.
	 */
	xfs_iunlock(ip, XFS_ILOCK_EXCL | XFS_IOLOCK_EXCL);
	xfs_idestroy(ip);
}

/*
 * This routine removes an about-to-be-destroyed inode from
 * all of the lists in which it is located with the exception
 * of the behavior chain.
 */
void
xfs_iextract(
	xfs_inode_t	*ip)
{
	xfs_mount_t	*mp = ip->i_mount;
	xfs_perag_t	*pag = xfs_get_perag(mp, ip->i_ino);
	xfs_inode_t	*iq;

	write_lock(&pag->pag_ici_lock);
	radix_tree_delete(&pag->pag_ici_root, XFS_INO_TO_AGINO(mp, ip->i_ino));
	write_unlock(&pag->pag_ici_lock);
	xfs_put_perag(mp, pag);

	/*
	 * Remove from cluster list
	 */
	mp = ip->i_mount;
	spin_lock(&ip->i_cluster->icl_lock);
	hlist_del(&ip->i_cnode);
	spin_unlock(&ip->i_cluster->icl_lock);

	/* was last inode in cluster? */
	if (hlist_empty(&ip->i_cluster->icl_inodes))
		kmem_zone_free(xfs_icluster_zone, ip->i_cluster);

	/*
	 * Remove from mount's inode list.
	 */
	XFS_MOUNT_ILOCK(mp);
	ASSERT((ip->i_mnext != NULL) && (ip->i_mprev != NULL));
	iq = ip->i_mnext;
	iq->i_mprev = ip->i_mprev;
	ip->i_mprev->i_mnext = iq;

	/*
	 * Fix up the head pointer if it points to the inode being deleted.
	 */
	if (mp->m_inodes == ip) {
		if (ip == iq) {
			mp->m_inodes = NULL;
		} else {
			mp->m_inodes = iq;
		}
	}

	/* Deal with the deleted inodes list */
	list_del_init(&ip->i_reclaim);

	mp->m_ireclaims++;
	XFS_MOUNT_IUNLOCK(mp);
}

/*
 * This is a wrapper routine around the xfs_ilock() routine
 * used to centralize some grungy code.  It is used in places
 * that wish to lock the inode solely for reading the extents.
 * The reason these places can't just call xfs_ilock(SHARED)
 * is that the inode lock also guards to bringing in of the
 * extents from disk for a file in b-tree format.  If the inode
 * is in b-tree format, then we need to lock the inode exclusively
 * until the extents are read in.  Locking it exclusively all
 * the time would limit our parallelism unnecessarily, though.
 * What we do instead is check to see if the extents have been
 * read in yet, and only lock the inode exclusively if they
 * have not.
 *
 * The function returns a value which should be given to the
 * corresponding xfs_iunlock_map_shared().  This value is
 * the mode in which the lock was actually taken.
 */
uint
xfs_ilock_map_shared(
	xfs_inode_t	*ip)
{
	uint	lock_mode;

	if ((ip->i_d.di_format == XFS_DINODE_FMT_BTREE) &&
	    ((ip->i_df.if_flags & XFS_IFEXTENTS) == 0)) {
		lock_mode = XFS_ILOCK_EXCL;
	} else {
		lock_mode = XFS_ILOCK_SHARED;
	}

	xfs_ilock(ip, lock_mode);

	return lock_mode;
}

/*
 * This is simply the unlock routine to go with xfs_ilock_map_shared().
 * All it does is call xfs_iunlock() with the given lock_mode.
 */
void
xfs_iunlock_map_shared(
	xfs_inode_t	*ip,
	unsigned int	lock_mode)
{
	xfs_iunlock(ip, lock_mode);
}

/*
 * The xfs inode contains 2 locks: a multi-reader lock called the
 * i_iolock and a multi-reader lock called the i_lock.  This routine
 * allows either or both of the locks to be obtained.
 *
 * The 2 locks should always be ordered so that the IO lock is
 * obtained first in order to prevent deadlock.
 *
 * ip -- the inode being locked
 * lock_flags -- this parameter indicates the inode's locks
 *       to be locked.  It can be:
 *		XFS_IOLOCK_SHARED,
 *		XFS_IOLOCK_EXCL,
 *		XFS_ILOCK_SHARED,
 *		XFS_ILOCK_EXCL,
 *		XFS_IOLOCK_SHARED | XFS_ILOCK_SHARED,
 *		XFS_IOLOCK_SHARED | XFS_ILOCK_EXCL,
 *		XFS_IOLOCK_EXCL | XFS_ILOCK_SHARED,
 *		XFS_IOLOCK_EXCL | XFS_ILOCK_EXCL
 */
void
xfs_ilock(xfs_inode_t	*ip,
	  uint		lock_flags)
{
	/*
	 * You can't set both SHARED and EXCL for the same lock,
	 * and only XFS_IOLOCK_SHARED, XFS_IOLOCK_EXCL, XFS_ILOCK_SHARED,
	 * and XFS_ILOCK_EXCL are valid values to set in lock_flags.
	 */
	ASSERT((lock_flags & (XFS_IOLOCK_SHARED | XFS_IOLOCK_EXCL)) !=
	       (XFS_IOLOCK_SHARED | XFS_IOLOCK_EXCL));
	ASSERT((lock_flags & (XFS_ILOCK_SHARED | XFS_ILOCK_EXCL)) !=
	       (XFS_ILOCK_SHARED | XFS_ILOCK_EXCL));
	ASSERT((lock_flags & ~(XFS_LOCK_MASK | XFS_LOCK_DEP_MASK)) == 0);

	if (lock_flags & XFS_IOLOCK_EXCL) {
		mrupdate_nested(&ip->i_iolock, XFS_IOLOCK_DEP(lock_flags));
	} else if (lock_flags & XFS_IOLOCK_SHARED) {
		mraccess_nested(&ip->i_iolock, XFS_IOLOCK_DEP(lock_flags));
	}
	if (lock_flags & XFS_ILOCK_EXCL) {
		mrupdate_nested(&ip->i_lock, XFS_ILOCK_DEP(lock_flags));
	} else if (lock_flags & XFS_ILOCK_SHARED) {
		mraccess_nested(&ip->i_lock, XFS_ILOCK_DEP(lock_flags));
	}
	xfs_ilock_trace(ip, 1, lock_flags, (inst_t *)__return_address);
}

/*
 * This is just like xfs_ilock(), except that the caller
 * is guaranteed not to sleep.  It returns 1 if it gets
 * the requested locks and 0 otherwise.  If the IO lock is
 * obtained but the inode lock cannot be, then the IO lock
 * is dropped before returning.
 *
 * ip -- the inode being locked
 * lock_flags -- this parameter indicates the inode's locks to be
 *       to be locked.  See the comment for xfs_ilock() for a list
 *	 of valid values.
 *
 */
int
xfs_ilock_nowait(xfs_inode_t	*ip,
		 uint		lock_flags)
{
	int	iolocked;
	int	ilocked;

	/*
	 * You can't set both SHARED and EXCL for the same lock,
	 * and only XFS_IOLOCK_SHARED, XFS_IOLOCK_EXCL, XFS_ILOCK_SHARED,
	 * and XFS_ILOCK_EXCL are valid values to set in lock_flags.
	 */
	ASSERT((lock_flags & (XFS_IOLOCK_SHARED | XFS_IOLOCK_EXCL)) !=
	       (XFS_IOLOCK_SHARED | XFS_IOLOCK_EXCL));
	ASSERT((lock_flags & (XFS_ILOCK_SHARED | XFS_ILOCK_EXCL)) !=
	       (XFS_ILOCK_SHARED | XFS_ILOCK_EXCL));
	ASSERT((lock_flags & ~(XFS_LOCK_MASK | XFS_LOCK_DEP_MASK)) == 0);

	iolocked = 0;
	if (lock_flags & XFS_IOLOCK_EXCL) {
		iolocked = mrtryupdate(&ip->i_iolock);
		if (!iolocked) {
			return 0;
		}
	} else if (lock_flags & XFS_IOLOCK_SHARED) {
		iolocked = mrtryaccess(&ip->i_iolock);
		if (!iolocked) {
			return 0;
		}
	}
	if (lock_flags & XFS_ILOCK_EXCL) {
		ilocked = mrtryupdate(&ip->i_lock);
		if (!ilocked) {
			if (iolocked) {
				mrunlock(&ip->i_iolock);
			}
			return 0;
		}
	} else if (lock_flags & XFS_ILOCK_SHARED) {
		ilocked = mrtryaccess(&ip->i_lock);
		if (!ilocked) {
			if (iolocked) {
				mrunlock(&ip->i_iolock);
			}
			return 0;
		}
	}
	xfs_ilock_trace(ip, 2, lock_flags, (inst_t *)__return_address);
	return 1;
}

/*
 * xfs_iunlock() is used to drop the inode locks acquired with
 * xfs_ilock() and xfs_ilock_nowait().  The caller must pass
 * in the flags given to xfs_ilock() or xfs_ilock_nowait() so
 * that we know which locks to drop.
 *
 * ip -- the inode being unlocked
 * lock_flags -- this parameter indicates the inode's locks to be
 *       to be unlocked.  See the comment for xfs_ilock() for a list
 *	 of valid values for this parameter.
 *
 */
void
xfs_iunlock(xfs_inode_t	*ip,
	    uint	lock_flags)
{
	/*
	 * You can't set both SHARED and EXCL for the same lock,
	 * and only XFS_IOLOCK_SHARED, XFS_IOLOCK_EXCL, XFS_ILOCK_SHARED,
	 * and XFS_ILOCK_EXCL are valid values to set in lock_flags.
	 */
	ASSERT((lock_flags & (XFS_IOLOCK_SHARED | XFS_IOLOCK_EXCL)) !=
	       (XFS_IOLOCK_SHARED | XFS_IOLOCK_EXCL));
	ASSERT((lock_flags & (XFS_ILOCK_SHARED | XFS_ILOCK_EXCL)) !=
	       (XFS_ILOCK_SHARED | XFS_ILOCK_EXCL));
	ASSERT((lock_flags & ~(XFS_LOCK_MASK | XFS_IUNLOCK_NONOTIFY |
			XFS_LOCK_DEP_MASK)) == 0);
	ASSERT(lock_flags != 0);

	if (lock_flags & (XFS_IOLOCK_SHARED | XFS_IOLOCK_EXCL)) {
		ASSERT(!(lock_flags & XFS_IOLOCK_SHARED) ||
		       (ismrlocked(&ip->i_iolock, MR_ACCESS)));
		ASSERT(!(lock_flags & XFS_IOLOCK_EXCL) ||
		       (ismrlocked(&ip->i_iolock, MR_UPDATE)));
		mrunlock(&ip->i_iolock);
	}

	if (lock_flags & (XFS_ILOCK_SHARED | XFS_ILOCK_EXCL)) {
		ASSERT(!(lock_flags & XFS_ILOCK_SHARED) ||
		       (ismrlocked(&ip->i_lock, MR_ACCESS)));
		ASSERT(!(lock_flags & XFS_ILOCK_EXCL) ||
		       (ismrlocked(&ip->i_lock, MR_UPDATE)));
		mrunlock(&ip->i_lock);

		/*
		 * Let the AIL know that this item has been unlocked in case
		 * it is in the AIL and anyone is waiting on it.  Don't do
		 * this if the caller has asked us not to.
		 */
		if (!(lock_flags & XFS_IUNLOCK_NONOTIFY) &&
		     ip->i_itemp != NULL) {
			xfs_trans_unlocked_item(ip->i_mount,
						(xfs_log_item_t*)(ip->i_itemp));
		}
	}
	xfs_ilock_trace(ip, 3, lock_flags, (inst_t *)__return_address);
}

/*
 * give up write locks.  the i/o lock cannot be held nested
 * if it is being demoted.
 */
void
xfs_ilock_demote(xfs_inode_t	*ip,
		 uint		lock_flags)
{
	ASSERT(lock_flags & (XFS_IOLOCK_EXCL|XFS_ILOCK_EXCL));
	ASSERT((lock_flags & ~(XFS_IOLOCK_EXCL|XFS_ILOCK_EXCL)) == 0);

	if (lock_flags & XFS_ILOCK_EXCL) {
		ASSERT(ismrlocked(&ip->i_lock, MR_UPDATE));
		mrdemote(&ip->i_lock);
	}
	if (lock_flags & XFS_IOLOCK_EXCL) {
		ASSERT(ismrlocked(&ip->i_iolock, MR_UPDATE));
		mrdemote(&ip->i_iolock);
	}
}

/*
 * The following three routines simply manage the i_flock
 * semaphore embedded in the inode.  This semaphore synchronizes
 * processes attempting to flush the in-core inode back to disk.
 */
void
xfs_iflock(xfs_inode_t *ip)
{
	psema(&(ip->i_flock), PINOD|PLTWAIT);
}

int
xfs_iflock_nowait(xfs_inode_t *ip)
{
	return (cpsema(&(ip->i_flock)));
}

void
xfs_ifunlock(xfs_inode_t *ip)
{
	ASSERT(issemalocked(&(ip->i_flock)));
	vsema(&(ip->i_flock));
}