forked from analogdevicesinc/linux
-
Notifications
You must be signed in to change notification settings - Fork 3
/
jfs_dmap.c
4092 lines (3605 loc) · 112 KB
/
jfs_dmap.c
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
/*
* Copyright (C) International Business Machines Corp., 2000-2004
* Portions Copyright (C) Tino Reichardt, 2012
*
* 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 02111-1307 USA
*/
#include <linux/fs.h>
#include <linux/slab.h>
#include "jfs_incore.h"
#include "jfs_superblock.h"
#include "jfs_dmap.h"
#include "jfs_imap.h"
#include "jfs_lock.h"
#include "jfs_metapage.h"
#include "jfs_debug.h"
#include "jfs_discard.h"
/*
* SERIALIZATION of the Block Allocation Map.
*
* the working state of the block allocation map is accessed in
* two directions:
*
* 1) allocation and free requests that start at the dmap
* level and move up through the dmap control pages (i.e.
* the vast majority of requests).
*
* 2) allocation requests that start at dmap control page
* level and work down towards the dmaps.
*
* the serialization scheme used here is as follows.
*
* requests which start at the bottom are serialized against each
* other through buffers and each requests holds onto its buffers
* as it works it way up from a single dmap to the required level
* of dmap control page.
* requests that start at the top are serialized against each other
* and request that start from the bottom by the multiple read/single
* write inode lock of the bmap inode. requests starting at the top
* take this lock in write mode while request starting at the bottom
* take the lock in read mode. a single top-down request may proceed
* exclusively while multiple bottoms-up requests may proceed
* simultaneously (under the protection of busy buffers).
*
* in addition to information found in dmaps and dmap control pages,
* the working state of the block allocation map also includes read/
* write information maintained in the bmap descriptor (i.e. total
* free block count, allocation group level free block counts).
* a single exclusive lock (BMAP_LOCK) is used to guard this information
* in the face of multiple-bottoms up requests.
* (lock ordering: IREAD_LOCK, BMAP_LOCK);
*
* accesses to the persistent state of the block allocation map (limited
* to the persistent bitmaps in dmaps) is guarded by (busy) buffers.
*/
#define BMAP_LOCK_INIT(bmp) mutex_init(&bmp->db_bmaplock)
#define BMAP_LOCK(bmp) mutex_lock(&bmp->db_bmaplock)
#define BMAP_UNLOCK(bmp) mutex_unlock(&bmp->db_bmaplock)
/*
* forward references
*/
static void dbAllocBits(struct bmap * bmp, struct dmap * dp, s64 blkno,
int nblocks);
static void dbSplit(dmtree_t * tp, int leafno, int splitsz, int newval);
static int dbBackSplit(dmtree_t * tp, int leafno);
static int dbJoin(dmtree_t * tp, int leafno, int newval);
static void dbAdjTree(dmtree_t * tp, int leafno, int newval);
static int dbAdjCtl(struct bmap * bmp, s64 blkno, int newval, int alloc,
int level);
static int dbAllocAny(struct bmap * bmp, s64 nblocks, int l2nb, s64 * results);
static int dbAllocNext(struct bmap * bmp, struct dmap * dp, s64 blkno,
int nblocks);
static int dbAllocNear(struct bmap * bmp, struct dmap * dp, s64 blkno,
int nblocks,
int l2nb, s64 * results);
static int dbAllocDmap(struct bmap * bmp, struct dmap * dp, s64 blkno,
int nblocks);
static int dbAllocDmapLev(struct bmap * bmp, struct dmap * dp, int nblocks,
int l2nb,
s64 * results);
static int dbAllocAG(struct bmap * bmp, int agno, s64 nblocks, int l2nb,
s64 * results);
static int dbAllocCtl(struct bmap * bmp, s64 nblocks, int l2nb, s64 blkno,
s64 * results);
static int dbExtend(struct inode *ip, s64 blkno, s64 nblocks, s64 addnblocks);
static int dbFindBits(u32 word, int l2nb);
static int dbFindCtl(struct bmap * bmp, int l2nb, int level, s64 * blkno);
static int dbFindLeaf(dmtree_t * tp, int l2nb, int *leafidx);
static int dbFreeBits(struct bmap * bmp, struct dmap * dp, s64 blkno,
int nblocks);
static int dbFreeDmap(struct bmap * bmp, struct dmap * dp, s64 blkno,
int nblocks);
static int dbMaxBud(u8 * cp);
static int blkstol2(s64 nb);
static int cntlz(u32 value);
static int cnttz(u32 word);
static int dbAllocDmapBU(struct bmap * bmp, struct dmap * dp, s64 blkno,
int nblocks);
static int dbInitDmap(struct dmap * dp, s64 blkno, int nblocks);
static int dbInitDmapTree(struct dmap * dp);
static int dbInitTree(struct dmaptree * dtp);
static int dbInitDmapCtl(struct dmapctl * dcp, int level, int i);
static int dbGetL2AGSize(s64 nblocks);
/*
* buddy table
*
* table used for determining buddy sizes within characters of
* dmap bitmap words. the characters themselves serve as indexes
* into the table, with the table elements yielding the maximum
* binary buddy of free bits within the character.
*/
static const s8 budtab[256] = {
3, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
2, 1, 1, 1, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0,
2, 1, 1, 1, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0,
2, 1, 1, 1, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0,
2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
2, 1, 1, 1, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0,
2, 1, 1, 1, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0,
2, 1, 1, 1, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0,
2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
2, 1, 1, 1, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0,
2, 1, 1, 1, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0,
2, 1, 1, 1, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, -1
};
/*
* NAME: dbMount()
*
* FUNCTION: initializate the block allocation map.
*
* memory is allocated for the in-core bmap descriptor and
* the in-core descriptor is initialized from disk.
*
* PARAMETERS:
* ipbmap - pointer to in-core inode for the block map.
*
* RETURN VALUES:
* 0 - success
* -ENOMEM - insufficient memory
* -EIO - i/o error
*/
int dbMount(struct inode *ipbmap)
{
struct bmap *bmp;
struct dbmap_disk *dbmp_le;
struct metapage *mp;
int i;
/*
* allocate/initialize the in-memory bmap descriptor
*/
/* allocate memory for the in-memory bmap descriptor */
bmp = kmalloc(sizeof(struct bmap), GFP_KERNEL);
if (bmp == NULL)
return -ENOMEM;
/* read the on-disk bmap descriptor. */
mp = read_metapage(ipbmap,
BMAPBLKNO << JFS_SBI(ipbmap->i_sb)->l2nbperpage,
PSIZE, 0);
if (mp == NULL) {
kfree(bmp);
return -EIO;
}
/* copy the on-disk bmap descriptor to its in-memory version. */
dbmp_le = (struct dbmap_disk *) mp->data;
bmp->db_mapsize = le64_to_cpu(dbmp_le->dn_mapsize);
bmp->db_nfree = le64_to_cpu(dbmp_le->dn_nfree);
bmp->db_l2nbperpage = le32_to_cpu(dbmp_le->dn_l2nbperpage);
bmp->db_numag = le32_to_cpu(dbmp_le->dn_numag);
bmp->db_maxlevel = le32_to_cpu(dbmp_le->dn_maxlevel);
bmp->db_maxag = le32_to_cpu(dbmp_le->dn_maxag);
bmp->db_agpref = le32_to_cpu(dbmp_le->dn_agpref);
bmp->db_aglevel = le32_to_cpu(dbmp_le->dn_aglevel);
bmp->db_agheight = le32_to_cpu(dbmp_le->dn_agheight);
bmp->db_agwidth = le32_to_cpu(dbmp_le->dn_agwidth);
bmp->db_agstart = le32_to_cpu(dbmp_le->dn_agstart);
bmp->db_agl2size = le32_to_cpu(dbmp_le->dn_agl2size);
for (i = 0; i < MAXAG; i++)
bmp->db_agfree[i] = le64_to_cpu(dbmp_le->dn_agfree[i]);
bmp->db_agsize = le64_to_cpu(dbmp_le->dn_agsize);
bmp->db_maxfreebud = dbmp_le->dn_maxfreebud;
/* release the buffer. */
release_metapage(mp);
/* bind the bmap inode and the bmap descriptor to each other. */
bmp->db_ipbmap = ipbmap;
JFS_SBI(ipbmap->i_sb)->bmap = bmp;
memset(bmp->db_active, 0, sizeof(bmp->db_active));
/*
* allocate/initialize the bmap lock
*/
BMAP_LOCK_INIT(bmp);
return (0);
}
/*
* NAME: dbUnmount()
*
* FUNCTION: terminate the block allocation map in preparation for
* file system unmount.
*
* the in-core bmap descriptor is written to disk and
* the memory for this descriptor is freed.
*
* PARAMETERS:
* ipbmap - pointer to in-core inode for the block map.
*
* RETURN VALUES:
* 0 - success
* -EIO - i/o error
*/
int dbUnmount(struct inode *ipbmap, int mounterror)
{
struct bmap *bmp = JFS_SBI(ipbmap->i_sb)->bmap;
if (!(mounterror || isReadOnly(ipbmap)))
dbSync(ipbmap);
/*
* Invalidate the page cache buffers
*/
truncate_inode_pages(ipbmap->i_mapping, 0);
/* free the memory for the in-memory bmap. */
kfree(bmp);
return (0);
}
/*
* dbSync()
*/
int dbSync(struct inode *ipbmap)
{
struct dbmap_disk *dbmp_le;
struct bmap *bmp = JFS_SBI(ipbmap->i_sb)->bmap;
struct metapage *mp;
int i;
/*
* write bmap global control page
*/
/* get the buffer for the on-disk bmap descriptor. */
mp = read_metapage(ipbmap,
BMAPBLKNO << JFS_SBI(ipbmap->i_sb)->l2nbperpage,
PSIZE, 0);
if (mp == NULL) {
jfs_err("dbSync: read_metapage failed!");
return -EIO;
}
/* copy the in-memory version of the bmap to the on-disk version */
dbmp_le = (struct dbmap_disk *) mp->data;
dbmp_le->dn_mapsize = cpu_to_le64(bmp->db_mapsize);
dbmp_le->dn_nfree = cpu_to_le64(bmp->db_nfree);
dbmp_le->dn_l2nbperpage = cpu_to_le32(bmp->db_l2nbperpage);
dbmp_le->dn_numag = cpu_to_le32(bmp->db_numag);
dbmp_le->dn_maxlevel = cpu_to_le32(bmp->db_maxlevel);
dbmp_le->dn_maxag = cpu_to_le32(bmp->db_maxag);
dbmp_le->dn_agpref = cpu_to_le32(bmp->db_agpref);
dbmp_le->dn_aglevel = cpu_to_le32(bmp->db_aglevel);
dbmp_le->dn_agheight = cpu_to_le32(bmp->db_agheight);
dbmp_le->dn_agwidth = cpu_to_le32(bmp->db_agwidth);
dbmp_le->dn_agstart = cpu_to_le32(bmp->db_agstart);
dbmp_le->dn_agl2size = cpu_to_le32(bmp->db_agl2size);
for (i = 0; i < MAXAG; i++)
dbmp_le->dn_agfree[i] = cpu_to_le64(bmp->db_agfree[i]);
dbmp_le->dn_agsize = cpu_to_le64(bmp->db_agsize);
dbmp_le->dn_maxfreebud = bmp->db_maxfreebud;
/* write the buffer */
write_metapage(mp);
/*
* write out dirty pages of bmap
*/
filemap_write_and_wait(ipbmap->i_mapping);
diWriteSpecial(ipbmap, 0);
return (0);
}
/*
* NAME: dbFree()
*
* FUNCTION: free the specified block range from the working block
* allocation map.
*
* the blocks will be free from the working map one dmap
* at a time.
*
* PARAMETERS:
* ip - pointer to in-core inode;
* blkno - starting block number to be freed.
* nblocks - number of blocks to be freed.
*
* RETURN VALUES:
* 0 - success
* -EIO - i/o error
*/
int dbFree(struct inode *ip, s64 blkno, s64 nblocks)
{
struct metapage *mp;
struct dmap *dp;
int nb, rc;
s64 lblkno, rem;
struct inode *ipbmap = JFS_SBI(ip->i_sb)->ipbmap;
struct bmap *bmp = JFS_SBI(ip->i_sb)->bmap;
struct super_block *sb = ipbmap->i_sb;
IREAD_LOCK(ipbmap, RDWRLOCK_DMAP);
/* block to be freed better be within the mapsize. */
if (unlikely((blkno == 0) || (blkno + nblocks > bmp->db_mapsize))) {
IREAD_UNLOCK(ipbmap);
printk(KERN_ERR "blkno = %Lx, nblocks = %Lx\n",
(unsigned long long) blkno,
(unsigned long long) nblocks);
jfs_error(ip->i_sb, "block to be freed is outside the map\n");
return -EIO;
}
/**
* TRIM the blocks, when mounted with discard option
*/
if (JFS_SBI(sb)->flag & JFS_DISCARD)
if (JFS_SBI(sb)->minblks_trim <= nblocks)
jfs_issue_discard(ipbmap, blkno, nblocks);
/*
* free the blocks a dmap at a time.
*/
mp = NULL;
for (rem = nblocks; rem > 0; rem -= nb, blkno += nb) {
/* release previous dmap if any */
if (mp) {
write_metapage(mp);
}
/* get the buffer for the current dmap. */
lblkno = BLKTODMAP(blkno, bmp->db_l2nbperpage);
mp = read_metapage(ipbmap, lblkno, PSIZE, 0);
if (mp == NULL) {
IREAD_UNLOCK(ipbmap);
return -EIO;
}
dp = (struct dmap *) mp->data;
/* determine the number of blocks to be freed from
* this dmap.
*/
nb = min(rem, BPERDMAP - (blkno & (BPERDMAP - 1)));
/* free the blocks. */
if ((rc = dbFreeDmap(bmp, dp, blkno, nb))) {
jfs_error(ip->i_sb, "error in block map\n");
release_metapage(mp);
IREAD_UNLOCK(ipbmap);
return (rc);
}
}
/* write the last buffer. */
write_metapage(mp);
IREAD_UNLOCK(ipbmap);
return (0);
}
/*
* NAME: dbUpdatePMap()
*
* FUNCTION: update the allocation state (free or allocate) of the
* specified block range in the persistent block allocation map.
*
* the blocks will be updated in the persistent map one
* dmap at a time.
*
* PARAMETERS:
* ipbmap - pointer to in-core inode for the block map.
* free - 'true' if block range is to be freed from the persistent
* map; 'false' if it is to be allocated.
* blkno - starting block number of the range.
* nblocks - number of contiguous blocks in the range.
* tblk - transaction block;
*
* RETURN VALUES:
* 0 - success
* -EIO - i/o error
*/
int
dbUpdatePMap(struct inode *ipbmap,
int free, s64 blkno, s64 nblocks, struct tblock * tblk)
{
int nblks, dbitno, wbitno, rbits;
int word, nbits, nwords;
struct bmap *bmp = JFS_SBI(ipbmap->i_sb)->bmap;
s64 lblkno, rem, lastlblkno;
u32 mask;
struct dmap *dp;
struct metapage *mp;
struct jfs_log *log;
int lsn, difft, diffp;
unsigned long flags;
/* the blocks better be within the mapsize. */
if (blkno + nblocks > bmp->db_mapsize) {
printk(KERN_ERR "blkno = %Lx, nblocks = %Lx\n",
(unsigned long long) blkno,
(unsigned long long) nblocks);
jfs_error(ipbmap->i_sb, "blocks are outside the map\n");
return -EIO;
}
/* compute delta of transaction lsn from log syncpt */
lsn = tblk->lsn;
log = (struct jfs_log *) JFS_SBI(tblk->sb)->log;
logdiff(difft, lsn, log);
/*
* update the block state a dmap at a time.
*/
mp = NULL;
lastlblkno = 0;
for (rem = nblocks; rem > 0; rem -= nblks, blkno += nblks) {
/* get the buffer for the current dmap. */
lblkno = BLKTODMAP(blkno, bmp->db_l2nbperpage);
if (lblkno != lastlblkno) {
if (mp) {
write_metapage(mp);
}
mp = read_metapage(bmp->db_ipbmap, lblkno, PSIZE,
0);
if (mp == NULL)
return -EIO;
metapage_wait_for_io(mp);
}
dp = (struct dmap *) mp->data;
/* determine the bit number and word within the dmap of
* the starting block. also determine how many blocks
* are to be updated within this dmap.
*/
dbitno = blkno & (BPERDMAP - 1);
word = dbitno >> L2DBWORD;
nblks = min(rem, (s64)BPERDMAP - dbitno);
/* update the bits of the dmap words. the first and last
* words may only have a subset of their bits updated. if
* this is the case, we'll work against that word (i.e.
* partial first and/or last) only in a single pass. a
* single pass will also be used to update all words that
* are to have all their bits updated.
*/
for (rbits = nblks; rbits > 0;
rbits -= nbits, dbitno += nbits) {
/* determine the bit number within the word and
* the number of bits within the word.
*/
wbitno = dbitno & (DBWORD - 1);
nbits = min(rbits, DBWORD - wbitno);
/* check if only part of the word is to be updated. */
if (nbits < DBWORD) {
/* update (free or allocate) the bits
* in this word.
*/
mask =
(ONES << (DBWORD - nbits) >> wbitno);
if (free)
dp->pmap[word] &=
cpu_to_le32(~mask);
else
dp->pmap[word] |=
cpu_to_le32(mask);
word += 1;
} else {
/* one or more words are to have all
* their bits updated. determine how
* many words and how many bits.
*/
nwords = rbits >> L2DBWORD;
nbits = nwords << L2DBWORD;
/* update (free or allocate) the bits
* in these words.
*/
if (free)
memset(&dp->pmap[word], 0,
nwords * 4);
else
memset(&dp->pmap[word], (int) ONES,
nwords * 4);
word += nwords;
}
}
/*
* update dmap lsn
*/
if (lblkno == lastlblkno)
continue;
lastlblkno = lblkno;
LOGSYNC_LOCK(log, flags);
if (mp->lsn != 0) {
/* inherit older/smaller lsn */
logdiff(diffp, mp->lsn, log);
if (difft < diffp) {
mp->lsn = lsn;
/* move bp after tblock in logsync list */
list_move(&mp->synclist, &tblk->synclist);
}
/* inherit younger/larger clsn */
logdiff(difft, tblk->clsn, log);
logdiff(diffp, mp->clsn, log);
if (difft > diffp)
mp->clsn = tblk->clsn;
} else {
mp->log = log;
mp->lsn = lsn;
/* insert bp after tblock in logsync list */
log->count++;
list_add(&mp->synclist, &tblk->synclist);
mp->clsn = tblk->clsn;
}
LOGSYNC_UNLOCK(log, flags);
}
/* write the last buffer. */
if (mp) {
write_metapage(mp);
}
return (0);
}
/*
* NAME: dbNextAG()
*
* FUNCTION: find the preferred allocation group for new allocations.
*
* Within the allocation groups, we maintain a preferred
* allocation group which consists of a group with at least
* average free space. It is the preferred group that we target
* new inode allocation towards. The tie-in between inode
* allocation and block allocation occurs as we allocate the
* first (data) block of an inode and specify the inode (block)
* as the allocation hint for this block.
*
* We try to avoid having more than one open file growing in
* an allocation group, as this will lead to fragmentation.
* This differs from the old OS/2 method of trying to keep
* empty ags around for large allocations.
*
* PARAMETERS:
* ipbmap - pointer to in-core inode for the block map.
*
* RETURN VALUES:
* the preferred allocation group number.
*/
int dbNextAG(struct inode *ipbmap)
{
s64 avgfree;
int agpref;
s64 hwm = 0;
int i;
int next_best = -1;
struct bmap *bmp = JFS_SBI(ipbmap->i_sb)->bmap;
BMAP_LOCK(bmp);
/* determine the average number of free blocks within the ags. */
avgfree = (u32)bmp->db_nfree / bmp->db_numag;
/*
* if the current preferred ag does not have an active allocator
* and has at least average freespace, return it
*/
agpref = bmp->db_agpref;
if ((atomic_read(&bmp->db_active[agpref]) == 0) &&
(bmp->db_agfree[agpref] >= avgfree))
goto unlock;
/* From the last preferred ag, find the next one with at least
* average free space.
*/
for (i = 0 ; i < bmp->db_numag; i++, agpref++) {
if (agpref == bmp->db_numag)
agpref = 0;
if (atomic_read(&bmp->db_active[agpref]))
/* open file is currently growing in this ag */
continue;
if (bmp->db_agfree[agpref] >= avgfree) {
/* Return this one */
bmp->db_agpref = agpref;
goto unlock;
} else if (bmp->db_agfree[agpref] > hwm) {
/* Less than avg. freespace, but best so far */
hwm = bmp->db_agfree[agpref];
next_best = agpref;
}
}
/*
* If no inactive ag was found with average freespace, use the
* next best
*/
if (next_best != -1)
bmp->db_agpref = next_best;
/* else leave db_agpref unchanged */
unlock:
BMAP_UNLOCK(bmp);
/* return the preferred group.
*/
return (bmp->db_agpref);
}
/*
* NAME: dbAlloc()
*
* FUNCTION: attempt to allocate a specified number of contiguous free
* blocks from the working allocation block map.
*
* the block allocation policy uses hints and a multi-step
* approach.
*
* for allocation requests smaller than the number of blocks
* per dmap, we first try to allocate the new blocks
* immediately following the hint. if these blocks are not
* available, we try to allocate blocks near the hint. if
* no blocks near the hint are available, we next try to
* allocate within the same dmap as contains the hint.
*
* if no blocks are available in the dmap or the allocation
* request is larger than the dmap size, we try to allocate
* within the same allocation group as contains the hint. if
* this does not succeed, we finally try to allocate anywhere
* within the aggregate.
*
* we also try to allocate anywhere within the aggregate for
* for allocation requests larger than the allocation group
* size or requests that specify no hint value.
*
* PARAMETERS:
* ip - pointer to in-core inode;
* hint - allocation hint.
* nblocks - number of contiguous blocks in the range.
* results - on successful return, set to the starting block number
* of the newly allocated contiguous range.
*
* RETURN VALUES:
* 0 - success
* -ENOSPC - insufficient disk resources
* -EIO - i/o error
*/
int dbAlloc(struct inode *ip, s64 hint, s64 nblocks, s64 * results)
{
int rc, agno;
struct inode *ipbmap = JFS_SBI(ip->i_sb)->ipbmap;
struct bmap *bmp;
struct metapage *mp;
s64 lblkno, blkno;
struct dmap *dp;
int l2nb;
s64 mapSize;
int writers;
/* assert that nblocks is valid */
assert(nblocks > 0);
/* get the log2 number of blocks to be allocated.
* if the number of blocks is not a log2 multiple,
* it will be rounded up to the next log2 multiple.
*/
l2nb = BLKSTOL2(nblocks);
bmp = JFS_SBI(ip->i_sb)->bmap;
mapSize = bmp->db_mapsize;
/* the hint should be within the map */
if (hint >= mapSize) {
jfs_error(ip->i_sb, "the hint is outside the map\n");
return -EIO;
}
/* if the number of blocks to be allocated is greater than the
* allocation group size, try to allocate anywhere.
*/
if (l2nb > bmp->db_agl2size) {
IWRITE_LOCK(ipbmap, RDWRLOCK_DMAP);
rc = dbAllocAny(bmp, nblocks, l2nb, results);
goto write_unlock;
}
/*
* If no hint, let dbNextAG recommend an allocation group
*/
if (hint == 0)
goto pref_ag;
/* we would like to allocate close to the hint. adjust the
* hint to the block following the hint since the allocators
* will start looking for free space starting at this point.
*/
blkno = hint + 1;
if (blkno >= bmp->db_mapsize)
goto pref_ag;
agno = blkno >> bmp->db_agl2size;
/* check if blkno crosses over into a new allocation group.
* if so, check if we should allow allocations within this
* allocation group.
*/
if ((blkno & (bmp->db_agsize - 1)) == 0)
/* check if the AG is currently being written to.
* if so, call dbNextAG() to find a non-busy
* AG with sufficient free space.
*/
if (atomic_read(&bmp->db_active[agno]))
goto pref_ag;
/* check if the allocation request size can be satisfied from a
* single dmap. if so, try to allocate from the dmap containing
* the hint using a tiered strategy.
*/
if (nblocks <= BPERDMAP) {
IREAD_LOCK(ipbmap, RDWRLOCK_DMAP);
/* get the buffer for the dmap containing the hint.
*/
rc = -EIO;
lblkno = BLKTODMAP(blkno, bmp->db_l2nbperpage);
mp = read_metapage(ipbmap, lblkno, PSIZE, 0);
if (mp == NULL)
goto read_unlock;
dp = (struct dmap *) mp->data;
/* first, try to satisfy the allocation request with the
* blocks beginning at the hint.
*/
if ((rc = dbAllocNext(bmp, dp, blkno, (int) nblocks))
!= -ENOSPC) {
if (rc == 0) {
*results = blkno;
mark_metapage_dirty(mp);
}
release_metapage(mp);
goto read_unlock;
}
writers = atomic_read(&bmp->db_active[agno]);
if ((writers > 1) ||
((writers == 1) && (JFS_IP(ip)->active_ag != agno))) {
/*
* Someone else is writing in this allocation
* group. To avoid fragmenting, try another ag
*/
release_metapage(mp);
IREAD_UNLOCK(ipbmap);
goto pref_ag;
}
/* next, try to satisfy the allocation request with blocks
* near the hint.
*/
if ((rc =
dbAllocNear(bmp, dp, blkno, (int) nblocks, l2nb, results))
!= -ENOSPC) {
if (rc == 0)
mark_metapage_dirty(mp);
release_metapage(mp);
goto read_unlock;
}
/* try to satisfy the allocation request with blocks within
* the same dmap as the hint.
*/
if ((rc = dbAllocDmapLev(bmp, dp, (int) nblocks, l2nb, results))
!= -ENOSPC) {
if (rc == 0)
mark_metapage_dirty(mp);
release_metapage(mp);
goto read_unlock;
}
release_metapage(mp);
IREAD_UNLOCK(ipbmap);
}
/* try to satisfy the allocation request with blocks within
* the same allocation group as the hint.
*/
IWRITE_LOCK(ipbmap, RDWRLOCK_DMAP);
if ((rc = dbAllocAG(bmp, agno, nblocks, l2nb, results)) != -ENOSPC)
goto write_unlock;
IWRITE_UNLOCK(ipbmap);
pref_ag:
/*
* Let dbNextAG recommend a preferred allocation group
*/
agno = dbNextAG(ipbmap);
IWRITE_LOCK(ipbmap, RDWRLOCK_DMAP);
/* Try to allocate within this allocation group. if that fails, try to
* allocate anywhere in the map.
*/
if ((rc = dbAllocAG(bmp, agno, nblocks, l2nb, results)) == -ENOSPC)
rc = dbAllocAny(bmp, nblocks, l2nb, results);
write_unlock:
IWRITE_UNLOCK(ipbmap);
return (rc);
read_unlock:
IREAD_UNLOCK(ipbmap);
return (rc);
}
#ifdef _NOTYET
/*
* NAME: dbAllocExact()
*
* FUNCTION: try to allocate the requested extent;
*
* PARAMETERS:
* ip - pointer to in-core inode;
* blkno - extent address;
* nblocks - extent length;
*
* RETURN VALUES:
* 0 - success
* -ENOSPC - insufficient disk resources
* -EIO - i/o error
*/
int dbAllocExact(struct inode *ip, s64 blkno, int nblocks)
{
int rc;
struct inode *ipbmap = JFS_SBI(ip->i_sb)->ipbmap;
struct bmap *bmp = JFS_SBI(ip->i_sb)->bmap;
struct dmap *dp;
s64 lblkno;
struct metapage *mp;
IREAD_LOCK(ipbmap, RDWRLOCK_DMAP);
/*
* validate extent request:
*
* note: defragfs policy:
* max 64 blocks will be moved.
* allocation request size must be satisfied from a single dmap.
*/
if (nblocks <= 0 || nblocks > BPERDMAP || blkno >= bmp->db_mapsize) {
IREAD_UNLOCK(ipbmap);
return -EINVAL;
}
if (nblocks > ((s64) 1 << bmp->db_maxfreebud)) {
/* the free space is no longer available */
IREAD_UNLOCK(ipbmap);
return -ENOSPC;
}
/* read in the dmap covering the extent */
lblkno = BLKTODMAP(blkno, bmp->db_l2nbperpage);
mp = read_metapage(ipbmap, lblkno, PSIZE, 0);
if (mp == NULL) {
IREAD_UNLOCK(ipbmap);
return -EIO;
}
dp = (struct dmap *) mp->data;
/* try to allocate the requested extent */
rc = dbAllocNext(bmp, dp, blkno, nblocks);
IREAD_UNLOCK(ipbmap);
if (rc == 0)
mark_metapage_dirty(mp);
release_metapage(mp);
return (rc);
}
#endif /* _NOTYET */
/*
* NAME: dbReAlloc()
*
* FUNCTION: attempt to extend a current allocation by a specified
* number of blocks.
*
* this routine attempts to satisfy the allocation request
* by first trying to extend the existing allocation in
* place by allocating the additional blocks as the blocks
* immediately following the current allocation. if these
* blocks are not available, this routine will attempt to
* allocate a new set of contiguous blocks large enough
* to cover the existing allocation plus the additional
* number of blocks required.
*
* PARAMETERS:
* ip - pointer to in-core inode requiring allocation.
* blkno - starting block of the current allocation.
* nblocks - number of contiguous blocks within the current
* allocation.
* addnblocks - number of blocks to add to the allocation.
* results - on successful return, set to the starting block number
* of the existing allocation if the existing allocation
* was extended in place or to a newly allocated contiguous
* range if the existing allocation could not be extended
* in place.
*
* RETURN VALUES:
* 0 - success
* -ENOSPC - insufficient disk resources
* -EIO - i/o error
*/
int
dbReAlloc(struct inode *ip,
s64 blkno, s64 nblocks, s64 addnblocks, s64 * results)
{
int rc;
/* try to extend the allocation in place.
*/
if ((rc = dbExtend(ip, blkno, nblocks, addnblocks)) == 0) {
*results = blkno;
return (0);
} else {
if (rc != -ENOSPC)
return (rc);
}
/* could not extend the allocation in place, so allocate a
* new set of blocks for the entire request (i.e. try to get
* a range of contiguous blocks large enough to cover the
* existing allocation plus the additional blocks.)
*/
return (dbAlloc
(ip, blkno + nblocks - 1, addnblocks + nblocks, results));
}