summaryrefslogtreecommitdiff
path: root/fs/ocfs2/localalloc.c
blob: 85111d740c9d85c4f8fb358c3c59ca0431907b34 (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
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
/* -*- mode: c; c-basic-offset: 8; -*-
 * vim: noexpandtab sw=8 ts=8 sts=0:
 *
 * localalloc.c
 *
 * Node local data allocation
 *
 * Copyright (C) 2002, 2004 Oracle.  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; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will 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 to the
 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
 * Boston, MA 021110-1307, USA.
 */

#include <linux/fs.h>
#include <linux/types.h>
#include <linux/slab.h>
#include <linux/highmem.h>
#include <linux/bitops.h>

#include <cluster/masklog.h>

#include "ocfs2.h"

#include "alloc.h"
#include "blockcheck.h"
#include "dlmglue.h"
#include "inode.h"
#include "journal.h"
#include "localalloc.h"
#include "suballoc.h"
#include "super.h"
#include "sysfile.h"
#include "ocfs2_trace.h"

#include "buffer_head_io.h"

#define OCFS2_LOCAL_ALLOC(dinode)	(&((dinode)->id2.i_lab))

static u32 ocfs2_local_alloc_count_bits(struct ocfs2_dinode *alloc);

static int ocfs2_local_alloc_find_clear_bits(struct ocfs2_super *osb,
					     struct ocfs2_dinode *alloc,
					     u32 *numbits,
					     struct ocfs2_alloc_reservation *resv);

static void ocfs2_clear_local_alloc(struct ocfs2_dinode *alloc);

static int ocfs2_sync_local_to_main(struct ocfs2_super *osb,
				    handle_t *handle,
				    struct ocfs2_dinode *alloc,
				    struct inode *main_bm_inode,
				    struct buffer_head *main_bm_bh);

static int ocfs2_local_alloc_reserve_for_window(struct ocfs2_super *osb,
						struct ocfs2_alloc_context **ac,
						struct inode **bitmap_inode,
						struct buffer_head **bitmap_bh);

static int ocfs2_local_alloc_new_window(struct ocfs2_super *osb,
					handle_t *handle,
					struct ocfs2_alloc_context *ac);

static int ocfs2_local_alloc_slide_window(struct ocfs2_super *osb,
					  struct inode *local_alloc_inode);

/*
 * ocfs2_la_default_mb() - determine a default size, in megabytes of
 * the local alloc.
 *
 * Generally, we'd like to pick as large a local alloc as
 * possible. Performance on large workloads tends to scale
 * proportionally to la size. In addition to that, the reservations
 * code functions more efficiently as it can reserve more windows for
 * write.
 *
 * Some things work against us when trying to choose a large local alloc:
 *
 * - We need to ensure our sizing is picked to leave enough space in
 *   group descriptors for other allocations (such as block groups,
 *   etc). Picking default sizes which are a multiple of 4 could help
 *   - block groups are allocated in 2mb and 4mb chunks.
 *
 * - Likewise, we don't want to starve other nodes of bits on small
 *   file systems. This can easily be taken care of by limiting our
 *   default to a reasonable size (256M) on larger cluster sizes.
 *
 * - Some file systems can't support very large sizes - 4k and 8k in
 *   particular are limited to less than 128 and 256 megabytes respectively.
 *
 * The following reference table shows group descriptor and local
 * alloc maximums at various cluster sizes (4k blocksize)
 *
 * csize: 4K	group: 126M	la: 121M
 * csize: 8K	group: 252M	la: 243M
 * csize: 16K	group: 504M	la: 486M
 * csize: 32K	group: 1008M	la: 972M
 * csize: 64K	group: 2016M	la: 1944M
 * csize: 128K	group: 4032M	la: 3888M
 * csize: 256K	group: 8064M	la: 7776M
 * csize: 512K	group: 16128M	la: 15552M
 * csize: 1024K	group: 32256M	la: 31104M
 */
#define	OCFS2_LA_MAX_DEFAULT_MB	256
#define	OCFS2_LA_OLD_DEFAULT	8
unsigned int ocfs2_la_default_mb(struct ocfs2_super *osb)
{
	unsigned int la_mb;
	unsigned int gd_mb;
	unsigned int la_max_mb;
	unsigned int megs_per_slot;
	struct super_block *sb = osb->sb;

	gd_mb = ocfs2_clusters_to_megabytes(osb->sb,
		8 * ocfs2_group_bitmap_size(sb, 0, osb->s_feature_incompat));

	/*
	 * This takes care of files systems with very small group
	 * descriptors - 512 byte blocksize at cluster sizes lower
	 * than 16K and also 1k blocksize with 4k cluster size.
	 */
	if ((sb->s_blocksize == 512 && osb->s_clustersize <= 8192)
	    || (sb->s_blocksize == 1024 && osb->s_clustersize == 4096))
		return OCFS2_LA_OLD_DEFAULT;

	/*
	 * Leave enough room for some block groups and make the final
	 * value we work from a multiple of 4.
	 */
	gd_mb -= 16;
	gd_mb &= 0xFFFFFFFB;

	la_mb = gd_mb;

	/*
	 * Keep window sizes down to a reasonable default
	 */
	if (la_mb > OCFS2_LA_MAX_DEFAULT_MB) {
		/*
		 * Some clustersize / blocksize combinations will have
		 * given us a larger than OCFS2_LA_MAX_DEFAULT_MB
		 * default size, but get poor distribution when
		 * limited to exactly 256 megabytes.
		 *
		 * As an example, 16K clustersize at 4K blocksize
		 * gives us a cluster group size of 504M. Paring the
		 * local alloc size down to 256 however, would give us
		 * only one window and around 200MB left in the
		 * cluster group. Instead, find the first size below
		 * 256 which would give us an even distribution.
		 *
		 * Larger cluster group sizes actually work out pretty
		 * well when pared to 256, so we don't have to do this
		 * for any group that fits more than two
		 * OCFS2_LA_MAX_DEFAULT_MB windows.
		 */
		if (gd_mb > (2 * OCFS2_LA_MAX_DEFAULT_MB))
			la_mb = 256;
		else {
			unsigned int gd_mult = gd_mb;

			while (gd_mult > 256)
				gd_mult = gd_mult >> 1;

			la_mb = gd_mult;
		}
	}

	megs_per_slot = osb->osb_clusters_at_boot / osb->max_slots;
	megs_per_slot = ocfs2_clusters_to_megabytes(osb->sb, megs_per_slot);
	/* Too many nodes, too few disk clusters. */
	if (megs_per_slot < la_mb)
		la_mb = megs_per_slot;

	/* We can't store more bits than we can in a block. */
	la_max_mb = ocfs2_clusters_to_megabytes(osb->sb,
						ocfs2_local_alloc_size(sb) * 8);
	if (la_mb > la_max_mb)
		la_mb = la_max_mb;

	return la_mb;
}

void ocfs2_la_set_sizes(struct ocfs2_super *osb, int requested_mb)
{
	struct super_block *sb = osb->sb;
	unsigned int la_default_mb = ocfs2_la_default_mb(osb);
	unsigned int la_max_mb;

	la_max_mb = ocfs2_clusters_to_megabytes(sb,
						ocfs2_local_alloc_size(sb) * 8);

	trace_ocfs2_la_set_sizes(requested_mb, la_max_mb, la_default_mb);

	if (requested_mb == -1) {
		/* No user request - use defaults */
		osb->local_alloc_default_bits =
			ocfs2_megabytes_to_clusters(sb, la_default_mb);
	} else if (requested_mb > la_max_mb) {
		/* Request is too big, we give the maximum available */
		osb->local_alloc_default_bits =
			ocfs2_megabytes_to_clusters(sb, la_max_mb);
	} else {
		osb->local_alloc_default_bits =
			ocfs2_megabytes_to_clusters(sb, requested_mb);
	}

	osb->local_alloc_bits = osb->local_alloc_default_bits;
}

static inline int ocfs2_la_state_enabled(struct ocfs2_super *osb)
{
	return (osb->local_alloc_state == OCFS2_LA_THROTTLED ||
		osb->local_alloc_state == OCFS2_LA_ENABLED);
}

void ocfs2_local_alloc_seen_free_bits(struct ocfs2_super *osb,
				      unsigned int num_clusters)
{
	spin_lock(&osb->osb_lock);
	if (osb->local_alloc_state == OCFS2_LA_DISABLED ||
	    osb->local_alloc_state == OCFS2_LA_THROTTLED)
		if (num_clusters >= osb->local_alloc_default_bits) {
			cancel_delayed_work(&osb->la_enable_wq);
			osb->local_alloc_state = OCFS2_LA_ENABLED;
		}
	spin_unlock(&osb->osb_lock);
}

void ocfs2_la_enable_worker(struct work_struct *work)
{
	struct ocfs2_super *osb =
		container_of(work, struct ocfs2_super,
			     la_enable_wq.work);
	spin_lock(&osb->osb_lock);
	osb->local_alloc_state = OCFS2_LA_ENABLED;
	spin_unlock(&osb->osb_lock);
}

/*
 * Tell us whether a given allocation should use the local alloc
 * file. Otherwise, it has to go to the main bitmap.
 *
 * This function does semi-dirty reads of local alloc size and state!
 * This is ok however, as the values are re-checked once under mutex.
 */
int ocfs2_alloc_should_use_local(struct ocfs2_super *osb, u64 bits)
{
	int ret = 0;
	int la_bits;

	spin_lock(&osb->osb_lock);
	la_bits = osb->local_alloc_bits;

	if (!ocfs2_la_state_enabled(osb))
		goto bail;

	/* la_bits should be at least twice the size (in clusters) of
	 * a new block group. We want to be sure block group
	 * allocations go through the local alloc, so allow an
	 * allocation to take up to half the bitmap. */
	if (bits > (la_bits / 2))
		goto bail;

	ret = 1;
bail:
	trace_ocfs2_alloc_should_use_local(
	     (unsigned long long)bits, osb->local_alloc_state, la_bits, ret);
	spin_unlock(&osb->osb_lock);
	return ret;
}

int ocfs2_load_local_alloc(struct ocfs2_super *osb)
{
	int status = 0;
	struct ocfs2_dinode *alloc = NULL;
	struct buffer_head *alloc_bh = NULL;
	u32 num_used;
	struct inode *inode = NULL;
	struct ocfs2_local_alloc *la;

	if (osb->local_alloc_bits == 0)
		goto bail;

	if (osb->local_alloc_bits >= osb->bitmap_cpg) {
		mlog(ML_NOTICE, "Requested local alloc window %d is larger "
		     "than max possible %u. Using defaults.\n",
		     osb->local_alloc_bits, (osb->bitmap_cpg - 1));
		osb->local_alloc_bits =
			ocfs2_megabytes_to_clusters(osb->sb,
						    ocfs2_la_default_mb(osb));
	}

	/* read the alloc off disk */
	inode = ocfs2_get_system_file_inode(osb, LOCAL_ALLOC_SYSTEM_INODE,
					    osb->slot_num);
	if (!inode) {
		status = -EINVAL;
		mlog_errno(status);
		goto bail;
	}

	status = ocfs2_read_inode_block_full(inode, &alloc_bh,
					     OCFS2_BH_IGNORE_CACHE);
	if (status < 0) {
		mlog_errno(status);
		goto bail;
	}

	alloc = (struct ocfs2_dinode *) alloc_bh->b_data;
	la = OCFS2_LOCAL_ALLOC(alloc);

	if (!(le32_to_cpu(alloc->i_flags) &
	    (OCFS2_LOCAL_ALLOC_FL|OCFS2_BITMAP_FL))) {
		mlog(ML_ERROR, "Invalid local alloc inode, %llu\n",
		     (unsigned long long)OCFS2_I(inode)->ip_blkno);
		status = -EINVAL;
		goto bail;
	}

	if ((la->la_size == 0) ||
	    (le16_to_cpu(la->la_size) > ocfs2_local_alloc_size(inode->i_sb))) {
		mlog(ML_ERROR, "Local alloc size is invalid (la_size = %u)\n",
		     le16_to_cpu(la->la_size));
		status = -EINVAL;
		goto bail;
	}

	/* do a little verification. */
	num_used = ocfs2_local_alloc_count_bits(alloc);

	/* hopefully the local alloc has always been recovered before
	 * we load it. */
	if (num_used
	    || alloc->id1.bitmap1.i_used
	    || alloc->id1.bitmap1.i_total
	    || la->la_bm_off) {
		mlog(ML_ERROR, "inconsistent detected, clean journal with"
		     " unrecovered local alloc, please run fsck.ocfs2!\n"
		     "found = %u, set = %u, taken = %u, off = %u\n",
		     num_used, le32_to_cpu(alloc->id1.bitmap1.i_used),
		     le32_to_cpu(alloc->id1.bitmap1.i_total),
		     OCFS2_LOCAL_ALLOC(alloc)->la_bm_off);

		status = -EINVAL;
		goto bail;
	}

	osb->local_alloc_bh = alloc_bh;
	osb->local_alloc_state = OCFS2_LA_ENABLED;

bail:
	if (status < 0)
		brelse(alloc_bh);
	if (inode)
		iput(inode);

	trace_ocfs2_load_local_alloc(osb->local_alloc_bits);

	if (status)
		mlog_errno(status);
	return status;
}

/*
 * return any unused bits to the bitmap and write out a clean
 * local_alloc.
 *
 * local_alloc_bh is optional. If not passed, we will simply use the
 * one off osb. If you do pass it however, be warned that it *will* be
 * returned brelse'd and NULL'd out.*/
void ocfs2_shutdown_local_alloc(struct ocfs2_super *osb)
{
	int status;
	handle_t *handle;
	struct inode *local_alloc_inode = NULL;
	struct buffer_head *bh = NULL;
	struct buffer_head *main_bm_bh = NULL;
	struct inode *main_bm_inode = NULL;
	struct ocfs2_dinode *alloc_copy = NULL;
	struct ocfs2_dinode *alloc = NULL;

	cancel_delayed_work(&osb->la_enable_wq);
	flush_workqueue(ocfs2_wq);

	if (osb->local_alloc_state == OCFS2_LA_UNUSED)
		goto out;

	local_alloc_inode =
		ocfs2_get_system_file_inode(osb,
					    LOCAL_ALLOC_SYSTEM_INODE,
					    osb->slot_num);
	if (!local_alloc_inode) {
		status = -ENOENT;
		mlog_errno(status);
		goto out;
	}

	osb->local_alloc_state = OCFS2_LA_DISABLED;

	ocfs2_resmap_uninit(&osb->osb_la_resmap);

	main_bm_inode = ocfs2_get_system_file_inode(osb,
						    GLOBAL_BITMAP_SYSTEM_INODE,
						    OCFS2_INVALID_SLOT);
	if (!main_bm_inode) {
		status = -EINVAL;
		mlog_errno(status);
		goto out;
	}

	mutex_lock(&main_bm_inode->i_mutex);

	status = ocfs2_inode_lock(main_bm_inode, &main_bm_bh, 1);
	if (status < 0) {
		mlog_errno(status);
		goto out_mutex;
	}

	/* WINDOW_MOVE_CREDITS is a bit heavy... */
	handle = ocfs2_start_trans(osb, OCFS2_WINDOW_MOVE_CREDITS);
	if (IS_ERR(handle)) {
		mlog_errno(PTR_ERR(handle));
		handle = NULL;
		goto out_unlock;
	}

	bh = osb->local_alloc_bh;
	alloc = (struct ocfs2_dinode *) bh->b_data;

	alloc_copy = kmalloc(bh->b_size, GFP_NOFS);
	if (!alloc_copy) {
		status = -ENOMEM;
		goto out_commit;
	}
	memcpy(alloc_copy, alloc, bh->b_size);

	status = ocfs2_journal_access_di(handle, INODE_CACHE(local_alloc_inode),
					 bh, OCFS2_JOURNAL_ACCESS_WRITE);
	if (status < 0) {
		mlog_errno(status);
		goto out_commit;
	}

	ocfs2_clear_local_alloc(alloc);
	ocfs2_journal_dirty(handle, bh);

	brelse(bh);
	osb->local_alloc_bh = NULL;
	osb->local_alloc_state = OCFS2_LA_UNUSED;

	status = ocfs2_sync_local_to_main(osb, handle, alloc_copy,
					  main_bm_inode, main_bm_bh);
	if (status < 0)
		mlog_errno(status);

out_commit:
	ocfs2_commit_trans(osb, handle);

out_unlock:
	brelse(main_bm_bh);

	ocfs2_inode_unlock(main_bm_inode, 1);

out_mutex:
	mutex_unlock(&main_bm_inode->i_mutex);
	iput(main_bm_inode);

out:
	if (local_alloc_inode)
		iput(local_alloc_inode);

	kfree(alloc_copy);
}

/*
 * We want to free the bitmap bits outside of any recovery context as
 * we'll need a cluster lock to do so, but we must clear the local
 * alloc before giving up the recovered nodes journal. To solve this,
 * we kmalloc a copy of the local alloc before it's change for the
 * caller to process with ocfs2_complete_local_alloc_recovery
 */
int ocfs2_begin_local_alloc_recovery(struct ocfs2_super *osb,
				     int slot_num,
				     struct ocfs2_dinode **alloc_copy)
{
	int status = 0;
	struct buffer_head *alloc_bh = NULL;
	struct inode *inode = NULL;
	struct ocfs2_dinode *alloc;

	trace_ocfs2_begin_local_alloc_recovery(slot_num);

	*alloc_copy = NULL;

	inode = ocfs2_get_system_file_inode(osb,
					    LOCAL_ALLOC_SYSTEM_INODE,
					    slot_num);
	if (!inode) {
		status = -EINVAL;
		mlog_errno(status);
		goto bail;
	}

	mutex_lock(&inode->i_mutex);

	status = ocfs2_read_inode_block_full(inode, &alloc_bh,
					     OCFS2_BH_IGNORE_CACHE);
	if (status < 0) {
		mlog_errno(status);
		goto bail;
	}

	*alloc_copy = kmalloc(alloc_bh->b_size, GFP_KERNEL);
	if (!(*alloc_copy)) {
		status = -ENOMEM;
		goto bail;
	}
	memcpy((*alloc_copy), alloc_bh->b_data, alloc_bh->b_size);

	alloc = (struct ocfs2_dinode *) alloc_bh->b_data;
	ocfs2_clear_local_alloc(alloc);

	ocfs2_compute_meta_ecc(osb->sb, alloc_bh->b_data, &alloc->i_check);
	status = ocfs2_write_block(osb, alloc_bh, INODE_CACHE(inode));
	if (status < 0)
		mlog_errno(status);

bail:
	if (status < 0) {
		kfree(*alloc_copy);
		*alloc_copy = NULL;
	}

	brelse(alloc_bh);

	if (inode) {
		mutex_unlock(&inode->i_mutex);
		iput(inode);
	}

	if (status)
		mlog_errno(status);
	return status;
}

/*
 * Step 2: By now, we've completed the journal recovery, we've stamped
 * a clean local alloc on disk and dropped the node out of the
 * recovery map. Dlm locks will no longer stall, so lets clear out the
 * main bitmap.
 */
int ocfs2_complete_local_alloc_recovery(struct ocfs2_super *osb,
					struct ocfs2_dinode *alloc)
{
	int status;
	handle_t *handle;
	struct buffer_head *main_bm_bh = NULL;
	struct inode *main_bm_inode;

	main_bm_inode = ocfs2_get_system_file_inode(osb,
						    GLOBAL_BITMAP_SYSTEM_INODE,
						    OCFS2_INVALID_SLOT);
	if (!main_bm_inode) {
		status = -EINVAL;
		mlog_errno(status);
		goto out;
	}

	mutex_lock(&main_bm_inode->i_mutex);

	status = ocfs2_inode_lock(main_bm_inode, &main_bm_bh, 1);
	if (status < 0) {
		mlog_errno(status);
		goto out_mutex;
	}

	handle = ocfs2_start_trans(osb, OCFS2_WINDOW_MOVE_CREDITS);
	if (IS_ERR(handle)) {
		status = PTR_ERR(handle);
		handle = NULL;
		mlog_errno(status);
		goto out_unlock;
	}

	/* we want the bitmap change to be recorded on disk asap */
	handle->h_sync = 1;

	status = ocfs2_sync_local_to_main(osb, handle, alloc,
					  main_bm_inode, main_bm_bh);
	if (status < 0)
		mlog_errno(status);

	ocfs2_commit_trans(osb, handle);

out_unlock:
	ocfs2_inode_unlock(main_bm_inode, 1);

out_mutex:
	mutex_unlock(&main_bm_inode->i_mutex);

	brelse(main_bm_bh);

	iput(main_bm_inode);

out:
	if (!status)
		ocfs2_init_steal_slots(osb);
	if (status)
		mlog_errno(status);
	return status;
}

/*
 * make sure we've got at least bits_wanted contiguous bits in the
 * local alloc. You lose them when you drop i_mutex.
 *
 * We will add ourselves to the transaction passed in, but may start
 * our own in order to shift windows.
 */
int ocfs2_reserve_local_alloc_bits(struct ocfs2_super *osb,
				   u32 bits_wanted,
				   struct ocfs2_alloc_context *ac)
{
	int status;
	struct ocfs2_dinode *alloc;
	struct inode *local_alloc_inode;
	unsigned int free_bits;

	BUG_ON(!ac);

	local_alloc_inode =
		ocfs2_get_system_file_inode(osb,
					    LOCAL_ALLOC_SYSTEM_INODE,
					    osb->slot_num);
	if (!local_alloc_inode) {
		status = -ENOENT;
		mlog_errno(status);
		goto bail;
	}

	mutex_lock(&local_alloc_inode->i_mutex);

	/*
	 * We must double check state and allocator bits because
	 * another process may have changed them while holding i_mutex.
	 */
	spin_lock(&osb->osb_lock);
	if (!ocfs2_la_state_enabled(osb) ||
	    (bits_wanted > osb->local_alloc_bits)) {
		spin_unlock(&osb->osb_lock);
		status = -ENOSPC;
		goto bail;
	}
	spin_unlock(&osb->osb_lock);

	alloc = (struct ocfs2_dinode *) osb->local_alloc_bh->b_data;

#ifdef CONFIG_OCFS2_DEBUG_FS
	if (le32_to_cpu(alloc->id1.bitmap1.i_used) !=
	    ocfs2_local_alloc_count_bits(alloc)) {
		ocfs2_error(osb->sb, "local alloc inode %llu says it has %u used bits, but a count shows %u\n",
			    (unsigned long long)le64_to_cpu(alloc->i_blkno),
			    le32_to_cpu(alloc->id1.bitmap1.i_used),
			    ocfs2_local_alloc_count_bits(alloc));
		status = -EIO;
		goto bail;
	}
#endif

	free_bits = le32_to_cpu(alloc->id1.bitmap1.i_total) -
		le32_to_cpu(alloc->id1.bitmap1.i_used);
	if (bits_wanted > free_bits) {
		/* uhoh, window change time. */
		status =
			ocfs2_local_alloc_slide_window(osb, local_alloc_inode);
		if (status < 0) {
			if (status != -ENOSPC)
				mlog_errno(status);
			goto bail;
		}

		/*
		 * Under certain conditions, the window slide code
		 * might have reduced the number of bits available or
		 * disabled the the local alloc entirely. Re-check
		 * here and return -ENOSPC if necessary.
		 */
		status = -ENOSPC;
		if (!ocfs2_la_state_enabled(osb))
			goto bail;

		free_bits = le32_to_cpu(alloc->id1.bitmap1.i_total) -
			le32_to_cpu(alloc->id1.bitmap1.i_used);
		if (bits_wanted > free_bits)
			goto bail;
	}

	ac->ac_inode = local_alloc_inode;
	/* We should never use localalloc from another slot */
	ac->ac_alloc_slot = osb->slot_num;
	ac->ac_which = OCFS2_AC_USE_LOCAL;
	get_bh(osb->local_alloc_bh);
	ac->ac_bh = osb->local_alloc_bh;
	status = 0;
bail:
	if (status < 0 && local_alloc_inode) {
		mutex_unlock(&local_alloc_inode->i_mutex);
		iput(local_alloc_inode);
	}

	trace_ocfs2_reserve_local_alloc_bits(
		(unsigned long long)ac->ac_max_block,
		bits_wanted, osb->slot_num, status);

	if (status)
		mlog_errno(status);
	return status;
}

int ocfs2_claim_local_alloc_bits(struct ocfs2_super *osb,
				 handle_t *handle,
				 struct ocfs2_alloc_context *ac,
				 u32 bits_wanted,
				 u32 *bit_off,
				 u32 *num_bits)
{
	int status, start;
	struct inode *local_alloc_inode;
	void *bitmap;
	struct ocfs2_dinode *alloc;
	struct ocfs2_local_alloc *la;

	BUG_ON(ac->ac_which != OCFS2_AC_USE_LOCAL);

	local_alloc_inode = ac->ac_inode;
	alloc = (struct ocfs2_dinode *) osb->local_alloc_bh->b_data;
	la = OCFS2_LOCAL_ALLOC(alloc);

	start = ocfs2_local_alloc_find_clear_bits(osb, alloc, &bits_wanted,
						  ac->ac_resv);
	if (start == -1) {
		/* TODO: Shouldn't we just BUG here? */
		status = -ENOSPC;
		mlog_errno(status);
		goto bail;
	}

	bitmap = la->la_bitmap;
	*bit_off = le32_to_cpu(la->la_bm_off) + start;
	*num_bits = bits_wanted;

	status = ocfs2_journal_access_di(handle,
					 INODE_CACHE(local_alloc_inode),
					 osb->local_alloc_bh,
					 OCFS2_JOURNAL_ACCESS_WRITE);
	if (status < 0) {
		mlog_errno(status);
		goto bail;
	}

	ocfs2_resmap_claimed_bits(&osb->osb_la_resmap, ac->ac_resv, start,
				  bits_wanted);

	while(bits_wanted--)
		ocfs2_set_bit(start++, bitmap);

	le32_add_cpu(&alloc->id1.bitmap1.i_used, *num_bits);
	ocfs2_journal_dirty(handle, osb->local_alloc_bh);

bail:
	if (status)
		mlog_errno(status);
	return status;
}

int ocfs2_free_local_alloc_bits(struct ocfs2_super *osb,
				handle_t *handle,
				struct ocfs2_alloc_context *ac,
				u32 bit_off,
				u32 num_bits)
{
	int status, start;
	u32 clear_bits;
	struct inode *local_alloc_inode;
	void *bitmap;
	struct ocfs2_dinode *alloc;
	struct ocfs2_local_alloc *la;

	BUG_ON(ac->ac_which != OCFS2_AC_USE_LOCAL);

	local_alloc_inode = ac->ac_inode;
	alloc = (struct ocfs2_dinode *) osb->local_alloc_bh->b_data;
	la = OCFS2_LOCAL_ALLOC(alloc);

	bitmap = la->la_bitmap;
	start = bit_off - le32_to_cpu(la->la_bm_off);
	clear_bits = num_bits;

	status = ocfs2_journal_access_di(handle,
			INODE_CACHE(local_alloc_inode),
			osb->local_alloc_bh,
			OCFS2_JOURNAL_ACCESS_WRITE);
	if (status < 0) {
		mlog_errno(status);
		goto bail;
	}

	while (clear_bits--)
		ocfs2_clear_bit(start++, bitmap);

	le32_add_cpu(&alloc->id1.bitmap1.i_used, -num_bits);
	ocfs2_journal_dirty(handle, osb->local_alloc_bh);

bail:
	return status;
}

static u32 ocfs2_local_alloc_count_bits(struct ocfs2_dinode *alloc)
{
	u32 count;
	struct ocfs2_local_alloc *la = OCFS2_LOCAL_ALLOC(alloc);

	count = memweight(la->la_bitmap, le16_to_cpu(la->la_size));

	trace_ocfs2_local_alloc_count_bits(count);
	return count;
}

static int ocfs2_local_alloc_find_clear_bits(struct ocfs2_super *osb,
				     struct ocfs2_dinode *alloc,
				     u32 *numbits,
				     struct ocfs2_alloc_reservation *resv)
{
	int numfound = 0, bitoff, left, startoff, lastzero;
	int local_resv = 0;
	struct ocfs2_alloc_reservation r;
	void *bitmap = NULL;
	struct ocfs2_reservation_map *resmap = &osb->osb_la_resmap;

	if (!alloc->id1.bitmap1.i_total) {
		bitoff = -1;
		goto bail;
	}

	if (!resv) {
		local_resv = 1;
		ocfs2_resv_init_once(&r);
		ocfs2_resv_set_type(&r, OCFS2_RESV_FLAG_TMP);
		resv = &r;
	}

	numfound = *numbits;
	if (ocfs2_resmap_resv_bits(resmap, resv, &bitoff, &numfound) == 0) {
		if (numfound < *numbits)
			*numbits = numfound;
		goto bail;
	}

	/*
	 * Code error. While reservations are enabled, local
	 * allocation should _always_ go through them.
	 */
	BUG_ON(osb->osb_resv_level != 0);

	/*
	 * Reservations are disabled. Handle this the old way.
	 */

	bitmap = OCFS2_LOCAL_ALLOC(alloc)->la_bitmap;

	numfound = bitoff = startoff = 0;
	lastzero = -1;
	left = le32_to_cpu(alloc->id1.bitmap1.i_total);
	while ((bitoff = ocfs2_find_next_zero_bit(bitmap, left, startoff)) != -1) {
		if (bitoff == left) {
			/* mlog(0, "bitoff (%d) == left", bitoff); */
			break;
		}
		/* mlog(0, "Found a zero: bitoff = %d, startoff = %d, "
		   "numfound = %d\n", bitoff, startoff, numfound);*/

		/* Ok, we found a zero bit... is it contig. or do we
		 * start over?*/
		if (bitoff == startoff) {
			/* we found a zero */
			numfound++;
			startoff++;
		} else {
			/* got a zero after some ones */
			numfound = 1;
			startoff = bitoff+1;
		}
		/* we got everything we needed */
		if (numfound == *numbits) {
			/* mlog(0, "Found it all!\n"); */
			break;
		}
	}

	trace_ocfs2_local_alloc_find_clear_bits_search_bitmap(bitoff, numfound);

	if (numfound == *numbits)
		bitoff = startoff - numfound;
	else
		bitoff = -1;

bail:
	if (local_resv)
		ocfs2_resv_discard(resmap, resv);

	trace_ocfs2_local_alloc_find_clear_bits(*numbits,
		le32_to_cpu(alloc->id1.bitmap1.i_total),
		bitoff, numfound);

	return bitoff;
}

static void ocfs2_clear_local_alloc(struct ocfs2_dinode *alloc)
{
	struct ocfs2_local_alloc *la = OCFS2_LOCAL_ALLOC(alloc);
	int i;

	alloc->id1.bitmap1.i_total = 0;
	alloc->id1.bitmap1.i_used = 0;
	la->la_bm_off = 0;
	for(i = 0; i < le16_to_cpu(la->la_size); i++)
		la->la_bitmap[i] = 0;
}

#if 0
/* turn this on and uncomment below to aid debugging window shifts. */
static void ocfs2_verify_zero_bits(unsigned long *bitmap,
				   unsigned int start,
				   unsigned int count)
{
	unsigned int tmp = count;
	while(tmp--) {
		if (ocfs2_test_bit(start + tmp, bitmap)) {
			printk("ocfs2_verify_zero_bits: start = %u, count = "
			       "%u\n", start, count);
			printk("ocfs2_verify_zero_bits: bit %u is set!",
			       start + tmp);
			BUG();
		}
	}
}
#endif

/*
 * sync the local alloc to main bitmap.
 *
 * assumes you've already locked the main bitmap -- the bitmap inode
 * passed is used for caching.
 */
static int ocfs2_sync_local_to_main(struct ocfs2_super *osb,
				    handle_t *handle,
				    struct ocfs2_dinode *alloc,
				    struct inode *main_bm_inode,
				    struct buffer_head *main_bm_bh)
{
	int status = 0;
	int bit_off, left, count, start;
	u64 la_start_blk;
	u64 blkno;
	void *bitmap;
	struct ocfs2_local_alloc *la = OCFS2_LOCAL_ALLOC(alloc);

	trace_ocfs2_sync_local_to_main(
	     le32_to_cpu(alloc->id1.bitmap1.i_total),
	     le32_to_cpu(alloc->id1.bitmap1.i_used));

	if (!alloc->id1.bitmap1.i_total) {
		goto bail;
	}

	if (le32_to_cpu(alloc->id1.bitmap1.i_used) ==
	    le32_to_cpu(alloc->id1.bitmap1.i_total)) {
		goto bail;
	}

	la_start_blk = ocfs2_clusters_to_blocks(osb->sb,
						le32_to_cpu(la->la_bm_off));
	bitmap = la->la_bitmap;
	start = count = bit_off = 0;
	left = le32_to_cpu(alloc->id1.bitmap1.i_total);

	while ((bit_off = ocfs2_find_next_zero_bit(bitmap, left, start))
	       != -1) {
		if ((bit_off < left) && (bit_off == start)) {
			count++;
			start++;
			continue;
		}
		if (count) {
			blkno = la_start_blk +
				ocfs2_clusters_to_blocks(osb->sb,
							 start - count);

			trace_ocfs2_sync_local_to_main_free(
			     count, start - count,
			     (unsigned long long)la_start_blk,
			     (unsigned long long)blkno);

			status = ocfs2_release_clusters(handle,
							main_bm_inode,
							main_bm_bh, blkno,
							count);
			if (status < 0) {
				mlog_errno(status);
				goto bail;
			}
		}
		if (bit_off >= left)
			break;
		count = 1;
		start = bit_off + 1;
	}

bail:
	if (status)
		mlog_errno(status);
	return status;
}

enum ocfs2_la_event {
	OCFS2_LA_EVENT_SLIDE,		/* Normal window slide. */
	OCFS2_LA_EVENT_FRAGMENTED,	/* The global bitmap has
					 * enough bits theoretically
					 * free, but a contiguous
					 * allocation could not be
					 * found. */
	OCFS2_LA_EVENT_ENOSPC,		/* Global bitmap doesn't have
					 * enough bits free to satisfy
					 * our request. */
};
#define OCFS2_LA_ENABLE_INTERVAL (30 * HZ)
/*
 * Given an event, calculate the size of our next local alloc window.
 *
 * This should always be called under i_mutex of the local alloc inode
 * so that local alloc disabling doesn't race with processes trying to
 * use the allocator.
 *
 * Returns the state which the local alloc was left in. This value can
 * be ignored by some paths.
 */
static int ocfs2_recalc_la_window(struct ocfs2_super *osb,
				  enum ocfs2_la_event event)
{
	unsigned int bits;
	int state;

	spin_lock(&osb->osb_lock);
	if (osb->local_alloc_state == OCFS2_LA_DISABLED) {
		WARN_ON_ONCE(osb->local_alloc_state == OCFS2_LA_DISABLED);
		goto out_unlock;
	}

	/*
	 * ENOSPC and fragmentation are treated similarly for now.
	 */
	if (event == OCFS2_LA_EVENT_ENOSPC ||
	    event == OCFS2_LA_EVENT_FRAGMENTED) {
		/*
		 * We ran out of contiguous space in the primary
		 * bitmap. Drastically reduce the number of bits used
		 * by local alloc until we have to disable it.
		 */
		bits = osb->local_alloc_bits >> 1;
		if (bits > ocfs2_megabytes_to_clusters(osb->sb, 1)) {
			/*
			 * By setting state to THROTTLED, we'll keep
			 * the number of local alloc bits used down
			 * until an event occurs which would give us
			 * reason to assume the bitmap situation might
			 * have changed.
			 */
			osb->local_alloc_state = OCFS2_LA_THROTTLED;
			osb->local_alloc_bits = bits;
		} else {
			osb->local_alloc_state = OCFS2_LA_DISABLED;
		}
		queue_delayed_work(ocfs2_wq, &osb->la_enable_wq,
				   OCFS2_LA_ENABLE_INTERVAL);
		goto out_unlock;
	}

	/*
	 * Don't increase the size of the local alloc window until we
	 * know we might be able to fulfill the request. Otherwise, we
	 * risk bouncing around the global bitmap during periods of
	 * low space.
	 */
	if (osb->local_alloc_state != OCFS2_LA_THROTTLED)
		osb->local_alloc_bits = osb->local_alloc_default_bits;

out_unlock:
	state = osb->local_alloc_state;
	spin_unlock(&osb->osb_lock);

	return state;
}

static int ocfs2_local_alloc_reserve_for_window(struct ocfs2_super *osb,
						struct ocfs2_alloc_context **ac,
						struct inode **bitmap_inode,
						struct buffer_head **bitmap_bh)
{
	int status;

	*ac = kzalloc(sizeof(struct ocfs2_alloc_context), GFP_KERNEL);
	if (!(*ac)) {
		status = -ENOMEM;
		mlog_errno(status);
		goto bail;
	}

retry_enospc:
	(*ac)->ac_bits_wanted = osb->local_alloc_bits;
	status = ocfs2_reserve_cluster_bitmap_bits(osb, *ac);
	if (status == -ENOSPC) {
		if (ocfs2_recalc_la_window(osb, OCFS2_LA_EVENT_ENOSPC) ==
		    OCFS2_LA_DISABLED)
			goto bail;

		ocfs2_free_ac_resource(*ac);
		memset(*ac, 0, sizeof(struct ocfs2_alloc_context));
		goto retry_enospc;
	}
	if (status < 0) {
		mlog_errno(status);
		goto bail;
	}

	*bitmap_inode = (*ac)->ac_inode;
	igrab(*bitmap_inode);
	*bitmap_bh = (*ac)->ac_bh;
	get_bh(*bitmap_bh);
	status = 0;
bail:
	if ((status < 0) && *ac) {
		ocfs2_free_alloc_context(*ac);
		*ac = NULL;
	}

	if (status)
		mlog_errno(status);
	return status;
}

/*
 * pass it the bitmap lock in lock_bh if you have it.
 */
static int ocfs2_local_alloc_new_window(struct ocfs2_super *osb,
					handle_t *handle,
					struct ocfs2_alloc_context *ac)
{
	int status = 0;
	u32 cluster_off, cluster_count;
	struct ocfs2_dinode *alloc = NULL;
	struct ocfs2_local_alloc *la;

	alloc = (struct ocfs2_dinode *) osb->local_alloc_bh->b_data;
	la = OCFS2_LOCAL_ALLOC(alloc);

	trace_ocfs2_local_alloc_new_window(
		le32_to_cpu(alloc->id1.bitmap1.i_total),
		osb->local_alloc_bits);

	/* Instruct the allocation code to try the most recently used
	 * cluster group. We'll re-record the group used this pass
	 * below. */
	ac->ac_last_group = osb->la_last_gd;

	/* we used the generic suballoc reserve function, but we set
	 * everything up nicely, so there's no reason why we can't use
	 * the more specific cluster api to claim bits. */
	status = ocfs2_claim_clusters(handle, ac, osb->local_alloc_bits,
				      &cluster_off, &cluster_count);
	if (status == -ENOSPC) {
retry_enospc:
		/*
		 * Note: We could also try syncing the journal here to
		 * allow use of any free bits which the current
		 * transaction can't give us access to. --Mark
		 */
		if (ocfs2_recalc_la_window(osb, OCFS2_LA_EVENT_FRAGMENTED) ==
		    OCFS2_LA_DISABLED)
			goto bail;

		ac->ac_bits_wanted = osb->local_alloc_bits;
		status = ocfs2_claim_clusters(handle, ac,
					      osb->local_alloc_bits,
					      &cluster_off,
					      &cluster_count);
		if (status == -ENOSPC)
			goto retry_enospc;
		/*
		 * We only shrunk the *minimum* number of in our
		 * request - it's entirely possible that the allocator
		 * might give us more than we asked for.
		 */
		if (status == 0) {
			spin_lock(&osb->osb_lock);
			osb->local_alloc_bits = cluster_count;
			spin_unlock(&osb->osb_lock);
		}
	}
	if (status < 0) {
		if (status != -ENOSPC)
			mlog_errno(status);
		goto bail;
	}

	osb->la_last_gd = ac->ac_last_group;

	la->la_bm_off = cpu_to_le32(cluster_off);
	alloc->id1.bitmap1.i_total = cpu_to_le32(cluster_count);
	/* just in case... In the future when we find space ourselves,
	 * we don't have to get all contiguous -- but we'll have to
	 * set all previously used bits in bitmap and update
	 * la_bits_set before setting the bits in the main bitmap. */
	alloc->id1.bitmap1.i_used = 0;
	memset(OCFS2_LOCAL_ALLOC(alloc)->la_bitmap, 0,
	       le16_to_cpu(la->la_size));

	ocfs2_resmap_restart(&osb->osb_la_resmap, cluster_count,
			     OCFS2_LOCAL_ALLOC(alloc)->la_bitmap);

	trace_ocfs2_local_alloc_new_window_result(
		OCFS2_LOCAL_ALLOC(alloc)->la_bm_off,
		le32_to_cpu(alloc->id1.bitmap1.i_total));

bail:
	if (status)
		mlog_errno(status);
	return status;
}

/* Note that we do *NOT* lock the local alloc inode here as
 * it's been locked already for us. */
static int ocfs2_local_alloc_slide_window(struct ocfs2_super *osb,
					  struct inode *local_alloc_inode)
{
	int status = 0;
	struct buffer_head *main_bm_bh = NULL;
	struct inode *main_bm_inode = NULL;
	handle_t *handle = NULL;
	struct ocfs2_dinode *alloc;
	struct ocfs2_dinode *alloc_copy = NULL;
	struct ocfs2_alloc_context *ac = NULL;

	ocfs2_recalc_la_window(osb, OCFS2_LA_EVENT_SLIDE);

	/* This will lock the main bitmap for us. */
	status = ocfs2_local_alloc_reserve_for_window(osb,
						      &ac,
						      &main_bm_inode,
						      &main_bm_bh);
	if (status < 0) {
		if (status != -ENOSPC)
			mlog_errno(status);
		goto bail;
	}

	handle = ocfs2_start_trans(osb, OCFS2_WINDOW_MOVE_CREDITS);
	if (IS_ERR(handle)) {
		status = PTR_ERR(handle);
		handle = NULL;
		mlog_errno(status);
		goto bail;
	}

	alloc = (struct ocfs2_dinode *) osb->local_alloc_bh->b_data;

	/* We want to clear the local alloc before doing anything
	 * else, so that if we error later during this operation,
	 * local alloc shutdown won't try to double free main bitmap
	 * bits. Make a copy so the sync function knows which bits to
	 * free. */
	alloc_copy = kmalloc(osb->local_alloc_bh->b_size, GFP_NOFS);
	if (!alloc_copy) {
		status = -ENOMEM;
		mlog_errno(status);
		goto bail;
	}
	memcpy(alloc_copy, alloc, osb->local_alloc_bh->b_size);

	status = ocfs2_journal_access_di(handle,
					 INODE_CACHE(local_alloc_inode),
					 osb->local_alloc_bh,
					 OCFS2_JOURNAL_ACCESS_WRITE);
	if (status < 0) {
		mlog_errno(status);
		goto bail;
	}

	ocfs2_clear_local_alloc(alloc);
	ocfs2_journal_dirty(handle, osb->local_alloc_bh);

	status = ocfs2_sync_local_to_main(osb, handle, alloc_copy,
					  main_bm_inode, main_bm_bh);
	if (status < 0) {
		mlog_errno(status);
		goto bail;
	}

	status = ocfs2_local_alloc_new_window(osb, handle, ac);
	if (status < 0) {
		if (status != -ENOSPC)
			mlog_errno(status);
		goto bail;
	}

	atomic_inc(&osb->alloc_stats.moves);

bail:
	if (handle)
		ocfs2_commit_trans(osb, handle);

	brelse(main_bm_bh);

	if (main_bm_inode)
		iput(main_bm_inode);

	kfree(alloc_copy);

	if (ac)
		ocfs2_free_alloc_context(ac);

	if (status)
		mlog_errno(status);
	return status;
}