forked from torvalds/linux
-
Notifications
You must be signed in to change notification settings - Fork 0
/
stree.c
2262 lines (2000 loc) · 64 KB
/
stree.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 2000 by Hans Reiser, licensing governed by reiserfs/README
*/
/*
* Written by Anatoly P. Pinchuk [email protected]
* Programm System Institute
* Pereslavl-Zalessky Russia
*/
#include <linux/time.h>
#include <linux/string.h>
#include <linux/pagemap.h>
#include "reiserfs.h"
#include <linux/buffer_head.h>
#include <linux/quotaops.h>
/* Does the buffer contain a disk block which is in the tree. */
inline int B_IS_IN_TREE(const struct buffer_head *bh)
{
RFALSE(B_LEVEL(bh) > MAX_HEIGHT,
"PAP-1010: block (%b) has too big level (%z)", bh, bh);
return (B_LEVEL(bh) != FREE_LEVEL);
}
/* to get item head in le form */
inline void copy_item_head(struct item_head *to,
const struct item_head *from)
{
memcpy(to, from, IH_SIZE);
}
/*
* k1 is pointer to on-disk structure which is stored in little-endian
* form. k2 is pointer to cpu variable. For key of items of the same
* object this returns 0.
* Returns: -1 if key1 < key2
* 0 if key1 == key2
* 1 if key1 > key2
*/
inline int comp_short_keys(const struct reiserfs_key *le_key,
const struct cpu_key *cpu_key)
{
__u32 n;
n = le32_to_cpu(le_key->k_dir_id);
if (n < cpu_key->on_disk_key.k_dir_id)
return -1;
if (n > cpu_key->on_disk_key.k_dir_id)
return 1;
n = le32_to_cpu(le_key->k_objectid);
if (n < cpu_key->on_disk_key.k_objectid)
return -1;
if (n > cpu_key->on_disk_key.k_objectid)
return 1;
return 0;
}
/*
* k1 is pointer to on-disk structure which is stored in little-endian
* form. k2 is pointer to cpu variable.
* Compare keys using all 4 key fields.
* Returns: -1 if key1 < key2 0
* if key1 = key2 1 if key1 > key2
*/
static inline int comp_keys(const struct reiserfs_key *le_key,
const struct cpu_key *cpu_key)
{
int retval;
retval = comp_short_keys(le_key, cpu_key);
if (retval)
return retval;
if (le_key_k_offset(le_key_version(le_key), le_key) <
cpu_key_k_offset(cpu_key))
return -1;
if (le_key_k_offset(le_key_version(le_key), le_key) >
cpu_key_k_offset(cpu_key))
return 1;
if (cpu_key->key_length == 3)
return 0;
/* this part is needed only when tail conversion is in progress */
if (le_key_k_type(le_key_version(le_key), le_key) <
cpu_key_k_type(cpu_key))
return -1;
if (le_key_k_type(le_key_version(le_key), le_key) >
cpu_key_k_type(cpu_key))
return 1;
return 0;
}
inline int comp_short_le_keys(const struct reiserfs_key *key1,
const struct reiserfs_key *key2)
{
__u32 *k1_u32, *k2_u32;
int key_length = REISERFS_SHORT_KEY_LEN;
k1_u32 = (__u32 *) key1;
k2_u32 = (__u32 *) key2;
for (; key_length--; ++k1_u32, ++k2_u32) {
if (le32_to_cpu(*k1_u32) < le32_to_cpu(*k2_u32))
return -1;
if (le32_to_cpu(*k1_u32) > le32_to_cpu(*k2_u32))
return 1;
}
return 0;
}
inline void le_key2cpu_key(struct cpu_key *to, const struct reiserfs_key *from)
{
int version;
to->on_disk_key.k_dir_id = le32_to_cpu(from->k_dir_id);
to->on_disk_key.k_objectid = le32_to_cpu(from->k_objectid);
/* find out version of the key */
version = le_key_version(from);
to->version = version;
to->on_disk_key.k_offset = le_key_k_offset(version, from);
to->on_disk_key.k_type = le_key_k_type(version, from);
}
/*
* this does not say which one is bigger, it only returns 1 if keys
* are not equal, 0 otherwise
*/
inline int comp_le_keys(const struct reiserfs_key *k1,
const struct reiserfs_key *k2)
{
return memcmp(k1, k2, sizeof(struct reiserfs_key));
}
/**************************************************************************
* Binary search toolkit function *
* Search for an item in the array by the item key *
* Returns: 1 if found, 0 if not found; *
* *pos = number of the searched element if found, else the *
* number of the first element that is larger than key. *
**************************************************************************/
/*
* For those not familiar with binary search: lbound is the leftmost item
* that it could be, rbound the rightmost item that it could be. We examine
* the item halfway between lbound and rbound, and that tells us either
* that we can increase lbound, or decrease rbound, or that we have found it,
* or if lbound <= rbound that there are no possible items, and we have not
* found it. With each examination we cut the number of possible items it
* could be by one more than half rounded down, or we find it.
*/
static inline int bin_search(const void *key, /* Key to search for. */
const void *base, /* First item in the array. */
int num, /* Number of items in the array. */
/*
* Item size in the array. searched. Lest the
* reader be confused, note that this is crafted
* as a general function, and when it is applied
* specifically to the array of item headers in a
* node, width is actually the item header size
* not the item size.
*/
int width,
int *pos /* Number of the searched for element. */
)
{
int rbound, lbound, j;
for (j = ((rbound = num - 1) + (lbound = 0)) / 2;
lbound <= rbound; j = (rbound + lbound) / 2)
switch (comp_keys
((struct reiserfs_key *)((char *)base + j * width),
(struct cpu_key *)key)) {
case -1:
lbound = j + 1;
continue;
case 1:
rbound = j - 1;
continue;
case 0:
*pos = j;
return ITEM_FOUND; /* Key found in the array. */
}
/*
* bin_search did not find given key, it returns position of key,
* that is minimal and greater than the given one.
*/
*pos = lbound;
return ITEM_NOT_FOUND;
}
/* Minimal possible key. It is never in the tree. */
const struct reiserfs_key MIN_KEY = { 0, 0, {{0, 0},} };
/* Maximal possible key. It is never in the tree. */
static const struct reiserfs_key MAX_KEY = {
cpu_to_le32(0xffffffff),
cpu_to_le32(0xffffffff),
{{cpu_to_le32(0xffffffff),
cpu_to_le32(0xffffffff)},}
};
/*
* Get delimiting key of the buffer by looking for it in the buffers in the
* path, starting from the bottom of the path, and going upwards. We must
* check the path's validity at each step. If the key is not in the path,
* there is no delimiting key in the tree (buffer is first or last buffer
* in tree), and in this case we return a special key, either MIN_KEY or
* MAX_KEY.
*/
static inline const struct reiserfs_key *get_lkey(const struct treepath *chk_path,
const struct super_block *sb)
{
int position, path_offset = chk_path->path_length;
struct buffer_head *parent;
RFALSE(path_offset < FIRST_PATH_ELEMENT_OFFSET,
"PAP-5010: invalid offset in the path");
/* While not higher in path than first element. */
while (path_offset-- > FIRST_PATH_ELEMENT_OFFSET) {
RFALSE(!buffer_uptodate
(PATH_OFFSET_PBUFFER(chk_path, path_offset)),
"PAP-5020: parent is not uptodate");
/* Parent at the path is not in the tree now. */
if (!B_IS_IN_TREE
(parent =
PATH_OFFSET_PBUFFER(chk_path, path_offset)))
return &MAX_KEY;
/* Check whether position in the parent is correct. */
if ((position =
PATH_OFFSET_POSITION(chk_path,
path_offset)) >
B_NR_ITEMS(parent))
return &MAX_KEY;
/* Check whether parent at the path really points to the child. */
if (B_N_CHILD_NUM(parent, position) !=
PATH_OFFSET_PBUFFER(chk_path,
path_offset + 1)->b_blocknr)
return &MAX_KEY;
/*
* Return delimiting key if position in the parent
* is not equal to zero.
*/
if (position)
return internal_key(parent, position - 1);
}
/* Return MIN_KEY if we are in the root of the buffer tree. */
if (PATH_OFFSET_PBUFFER(chk_path, FIRST_PATH_ELEMENT_OFFSET)->
b_blocknr == SB_ROOT_BLOCK(sb))
return &MIN_KEY;
return &MAX_KEY;
}
/* Get delimiting key of the buffer at the path and its right neighbor. */
inline const struct reiserfs_key *get_rkey(const struct treepath *chk_path,
const struct super_block *sb)
{
int position, path_offset = chk_path->path_length;
struct buffer_head *parent;
RFALSE(path_offset < FIRST_PATH_ELEMENT_OFFSET,
"PAP-5030: invalid offset in the path");
while (path_offset-- > FIRST_PATH_ELEMENT_OFFSET) {
RFALSE(!buffer_uptodate
(PATH_OFFSET_PBUFFER(chk_path, path_offset)),
"PAP-5040: parent is not uptodate");
/* Parent at the path is not in the tree now. */
if (!B_IS_IN_TREE
(parent =
PATH_OFFSET_PBUFFER(chk_path, path_offset)))
return &MIN_KEY;
/* Check whether position in the parent is correct. */
if ((position =
PATH_OFFSET_POSITION(chk_path,
path_offset)) >
B_NR_ITEMS(parent))
return &MIN_KEY;
/*
* Check whether parent at the path really points
* to the child.
*/
if (B_N_CHILD_NUM(parent, position) !=
PATH_OFFSET_PBUFFER(chk_path,
path_offset + 1)->b_blocknr)
return &MIN_KEY;
/*
* Return delimiting key if position in the parent
* is not the last one.
*/
if (position != B_NR_ITEMS(parent))
return internal_key(parent, position);
}
/* Return MAX_KEY if we are in the root of the buffer tree. */
if (PATH_OFFSET_PBUFFER(chk_path, FIRST_PATH_ELEMENT_OFFSET)->
b_blocknr == SB_ROOT_BLOCK(sb))
return &MAX_KEY;
return &MIN_KEY;
}
/*
* Check whether a key is contained in the tree rooted from a buffer at a path.
* This works by looking at the left and right delimiting keys for the buffer
* in the last path_element in the path. These delimiting keys are stored
* at least one level above that buffer in the tree. If the buffer is the
* first or last node in the tree order then one of the delimiting keys may
* be absent, and in this case get_lkey and get_rkey return a special key
* which is MIN_KEY or MAX_KEY.
*/
static inline int key_in_buffer(
/* Path which should be checked. */
struct treepath *chk_path,
/* Key which should be checked. */
const struct cpu_key *key,
struct super_block *sb
)
{
RFALSE(!key || chk_path->path_length < FIRST_PATH_ELEMENT_OFFSET
|| chk_path->path_length > MAX_HEIGHT,
"PAP-5050: pointer to the key(%p) is NULL or invalid path length(%d)",
key, chk_path->path_length);
RFALSE(!PATH_PLAST_BUFFER(chk_path)->b_bdev,
"PAP-5060: device must not be NODEV");
if (comp_keys(get_lkey(chk_path, sb), key) == 1)
/* left delimiting key is bigger, that the key we look for */
return 0;
/* if ( comp_keys(key, get_rkey(chk_path, sb)) != -1 ) */
if (comp_keys(get_rkey(chk_path, sb), key) != 1)
/* key must be less than right delimitiing key */
return 0;
return 1;
}
int reiserfs_check_path(struct treepath *p)
{
RFALSE(p->path_length != ILLEGAL_PATH_ELEMENT_OFFSET,
"path not properly relsed");
return 0;
}
/*
* Drop the reference to each buffer in a path and restore
* dirty bits clean when preparing the buffer for the log.
* This version should only be called from fix_nodes()
*/
void pathrelse_and_restore(struct super_block *sb,
struct treepath *search_path)
{
int path_offset = search_path->path_length;
RFALSE(path_offset < ILLEGAL_PATH_ELEMENT_OFFSET,
"clm-4000: invalid path offset");
while (path_offset > ILLEGAL_PATH_ELEMENT_OFFSET) {
struct buffer_head *bh;
bh = PATH_OFFSET_PBUFFER(search_path, path_offset--);
reiserfs_restore_prepared_buffer(sb, bh);
brelse(bh);
}
search_path->path_length = ILLEGAL_PATH_ELEMENT_OFFSET;
}
/* Drop the reference to each buffer in a path */
void pathrelse(struct treepath *search_path)
{
int path_offset = search_path->path_length;
RFALSE(path_offset < ILLEGAL_PATH_ELEMENT_OFFSET,
"PAP-5090: invalid path offset");
while (path_offset > ILLEGAL_PATH_ELEMENT_OFFSET)
brelse(PATH_OFFSET_PBUFFER(search_path, path_offset--));
search_path->path_length = ILLEGAL_PATH_ELEMENT_OFFSET;
}
static int is_leaf(char *buf, int blocksize, struct buffer_head *bh)
{
struct block_head *blkh;
struct item_head *ih;
int used_space;
int prev_location;
int i;
int nr;
blkh = (struct block_head *)buf;
if (blkh_level(blkh) != DISK_LEAF_NODE_LEVEL) {
reiserfs_warning(NULL, "reiserfs-5080",
"this should be caught earlier");
return 0;
}
nr = blkh_nr_item(blkh);
if (nr < 1 || nr > ((blocksize - BLKH_SIZE) / (IH_SIZE + MIN_ITEM_LEN))) {
/* item number is too big or too small */
reiserfs_warning(NULL, "reiserfs-5081",
"nr_item seems wrong: %z", bh);
return 0;
}
ih = (struct item_head *)(buf + BLKH_SIZE) + nr - 1;
used_space = BLKH_SIZE + IH_SIZE * nr + (blocksize - ih_location(ih));
/* free space does not match to calculated amount of use space */
if (used_space != blocksize - blkh_free_space(blkh)) {
reiserfs_warning(NULL, "reiserfs-5082",
"free space seems wrong: %z", bh);
return 0;
}
/*
* FIXME: it is_leaf will hit performance too much - we may have
* return 1 here
*/
/* check tables of item heads */
ih = (struct item_head *)(buf + BLKH_SIZE);
prev_location = blocksize;
for (i = 0; i < nr; i++, ih++) {
if (le_ih_k_type(ih) == TYPE_ANY) {
reiserfs_warning(NULL, "reiserfs-5083",
"wrong item type for item %h",
ih);
return 0;
}
if (ih_location(ih) >= blocksize
|| ih_location(ih) < IH_SIZE * nr) {
reiserfs_warning(NULL, "reiserfs-5084",
"item location seems wrong: %h",
ih);
return 0;
}
if (ih_item_len(ih) < 1
|| ih_item_len(ih) > MAX_ITEM_LEN(blocksize)) {
reiserfs_warning(NULL, "reiserfs-5085",
"item length seems wrong: %h",
ih);
return 0;
}
if (prev_location - ih_location(ih) != ih_item_len(ih)) {
reiserfs_warning(NULL, "reiserfs-5086",
"item location seems wrong "
"(second one): %h", ih);
return 0;
}
prev_location = ih_location(ih);
}
/* one may imagine many more checks */
return 1;
}
/* returns 1 if buf looks like an internal node, 0 otherwise */
static int is_internal(char *buf, int blocksize, struct buffer_head *bh)
{
struct block_head *blkh;
int nr;
int used_space;
blkh = (struct block_head *)buf;
nr = blkh_level(blkh);
if (nr <= DISK_LEAF_NODE_LEVEL || nr > MAX_HEIGHT) {
/* this level is not possible for internal nodes */
reiserfs_warning(NULL, "reiserfs-5087",
"this should be caught earlier");
return 0;
}
nr = blkh_nr_item(blkh);
/* for internal which is not root we might check min number of keys */
if (nr > (blocksize - BLKH_SIZE - DC_SIZE) / (KEY_SIZE + DC_SIZE)) {
reiserfs_warning(NULL, "reiserfs-5088",
"number of key seems wrong: %z", bh);
return 0;
}
used_space = BLKH_SIZE + KEY_SIZE * nr + DC_SIZE * (nr + 1);
if (used_space != blocksize - blkh_free_space(blkh)) {
reiserfs_warning(NULL, "reiserfs-5089",
"free space seems wrong: %z", bh);
return 0;
}
/* one may imagine many more checks */
return 1;
}
/*
* make sure that bh contains formatted node of reiserfs tree of
* 'level'-th level
*/
static int is_tree_node(struct buffer_head *bh, int level)
{
if (B_LEVEL(bh) != level) {
reiserfs_warning(NULL, "reiserfs-5090", "node level %d does "
"not match to the expected one %d",
B_LEVEL(bh), level);
return 0;
}
if (level == DISK_LEAF_NODE_LEVEL)
return is_leaf(bh->b_data, bh->b_size, bh);
return is_internal(bh->b_data, bh->b_size, bh);
}
#define SEARCH_BY_KEY_READA 16
/*
* The function is NOT SCHEDULE-SAFE!
* It might unlock the write lock if we needed to wait for a block
* to be read. Note that in this case it won't recover the lock to avoid
* high contention resulting from too much lock requests, especially
* the caller (search_by_key) will perform other schedule-unsafe
* operations just after calling this function.
*
* @return depth of lock to be restored after read completes
*/
static int search_by_key_reada(struct super_block *s,
struct buffer_head **bh,
b_blocknr_t *b, int num)
{
int i, j;
int depth = -1;
for (i = 0; i < num; i++) {
bh[i] = sb_getblk(s, b[i]);
}
/*
* We are going to read some blocks on which we
* have a reference. It's safe, though we might be
* reading blocks concurrently changed if we release
* the lock. But it's still fine because we check later
* if the tree changed
*/
for (j = 0; j < i; j++) {
/*
* note, this needs attention if we are getting rid of the BKL
* you have to make sure the prepared bit isn't set on this
* buffer
*/
if (!buffer_uptodate(bh[j])) {
if (depth == -1)
depth = reiserfs_write_unlock_nested(s);
ll_rw_block(REQ_OP_READ, REQ_RAHEAD, 1, bh + j);
}
brelse(bh[j]);
}
return depth;
}
/*
* This function fills up the path from the root to the leaf as it
* descends the tree looking for the key. It uses reiserfs_bread to
* try to find buffers in the cache given their block number. If it
* does not find them in the cache it reads them from disk. For each
* node search_by_key finds using reiserfs_bread it then uses
* bin_search to look through that node. bin_search will find the
* position of the block_number of the next node if it is looking
* through an internal node. If it is looking through a leaf node
* bin_search will find the position of the item which has key either
* equal to given key, or which is the maximal key less than the given
* key. search_by_key returns a path that must be checked for the
* correctness of the top of the path but need not be checked for the
* correctness of the bottom of the path
*/
/*
* search_by_key - search for key (and item) in stree
* @sb: superblock
* @key: pointer to key to search for
* @search_path: Allocated and initialized struct treepath; Returned filled
* on success.
* @stop_level: How far down the tree to search, Use DISK_LEAF_NODE_LEVEL to
* stop at leaf level.
*
* The function is NOT SCHEDULE-SAFE!
*/
int search_by_key(struct super_block *sb, const struct cpu_key *key,
struct treepath *search_path, int stop_level)
{
b_blocknr_t block_number;
int expected_level;
struct buffer_head *bh;
struct path_element *last_element;
int node_level, retval;
int right_neighbor_of_leaf_node;
int fs_gen;
struct buffer_head *reada_bh[SEARCH_BY_KEY_READA];
b_blocknr_t reada_blocks[SEARCH_BY_KEY_READA];
int reada_count = 0;
#ifdef CONFIG_REISERFS_CHECK
int repeat_counter = 0;
#endif
PROC_INFO_INC(sb, search_by_key);
/*
* As we add each node to a path we increase its count. This means
* that we must be careful to release all nodes in a path before we
* either discard the path struct or re-use the path struct, as we
* do here.
*/
pathrelse(search_path);
right_neighbor_of_leaf_node = 0;
/*
* With each iteration of this loop we search through the items in the
* current node, and calculate the next current node(next path element)
* for the next iteration of this loop..
*/
block_number = SB_ROOT_BLOCK(sb);
expected_level = -1;
while (1) {
#ifdef CONFIG_REISERFS_CHECK
if (!(++repeat_counter % 50000))
reiserfs_warning(sb, "PAP-5100",
"%s: there were %d iterations of "
"while loop looking for key %K",
current->comm, repeat_counter,
key);
#endif
/* prep path to have another element added to it. */
last_element =
PATH_OFFSET_PELEMENT(search_path,
++search_path->path_length);
fs_gen = get_generation(sb);
/*
* Read the next tree node, and set the last element
* in the path to have a pointer to it.
*/
if ((bh = last_element->pe_buffer =
sb_getblk(sb, block_number))) {
/*
* We'll need to drop the lock if we encounter any
* buffers that need to be read. If all of them are
* already up to date, we don't need to drop the lock.
*/
int depth = -1;
if (!buffer_uptodate(bh) && reada_count > 1)
depth = search_by_key_reada(sb, reada_bh,
reada_blocks, reada_count);
if (!buffer_uptodate(bh) && depth == -1)
depth = reiserfs_write_unlock_nested(sb);
ll_rw_block(REQ_OP_READ, 0, 1, &bh);
wait_on_buffer(bh);
if (depth != -1)
reiserfs_write_lock_nested(sb, depth);
if (!buffer_uptodate(bh))
goto io_error;
} else {
io_error:
search_path->path_length--;
pathrelse(search_path);
return IO_ERROR;
}
reada_count = 0;
if (expected_level == -1)
expected_level = SB_TREE_HEIGHT(sb);
expected_level--;
/*
* It is possible that schedule occurred. We must check
* whether the key to search is still in the tree rooted
* from the current buffer. If not then repeat search
* from the root.
*/
if (fs_changed(fs_gen, sb) &&
(!B_IS_IN_TREE(bh) ||
B_LEVEL(bh) != expected_level ||
!key_in_buffer(search_path, key, sb))) {
PROC_INFO_INC(sb, search_by_key_fs_changed);
PROC_INFO_INC(sb, search_by_key_restarted);
PROC_INFO_INC(sb,
sbk_restarted[expected_level - 1]);
pathrelse(search_path);
/*
* Get the root block number so that we can
* repeat the search starting from the root.
*/
block_number = SB_ROOT_BLOCK(sb);
expected_level = -1;
right_neighbor_of_leaf_node = 0;
/* repeat search from the root */
continue;
}
/*
* only check that the key is in the buffer if key is not
* equal to the MAX_KEY. Latter case is only possible in
* "finish_unfinished()" processing during mount.
*/
RFALSE(comp_keys(&MAX_KEY, key) &&
!key_in_buffer(search_path, key, sb),
"PAP-5130: key is not in the buffer");
#ifdef CONFIG_REISERFS_CHECK
if (REISERFS_SB(sb)->cur_tb) {
print_cur_tb("5140");
reiserfs_panic(sb, "PAP-5140",
"schedule occurred in do_balance!");
}
#endif
/*
* make sure, that the node contents look like a node of
* certain level
*/
if (!is_tree_node(bh, expected_level)) {
reiserfs_error(sb, "vs-5150",
"invalid format found in block %ld. "
"Fsck?", bh->b_blocknr);
pathrelse(search_path);
return IO_ERROR;
}
/* ok, we have acquired next formatted node in the tree */
node_level = B_LEVEL(bh);
PROC_INFO_BH_STAT(sb, bh, node_level - 1);
RFALSE(node_level < stop_level,
"vs-5152: tree level (%d) is less than stop level (%d)",
node_level, stop_level);
retval = bin_search(key, item_head(bh, 0),
B_NR_ITEMS(bh),
(node_level ==
DISK_LEAF_NODE_LEVEL) ? IH_SIZE :
KEY_SIZE,
&last_element->pe_position);
if (node_level == stop_level) {
return retval;
}
/* we are not in the stop level */
/*
* item has been found, so we choose the pointer which
* is to the right of the found one
*/
if (retval == ITEM_FOUND)
last_element->pe_position++;
/*
* if item was not found we choose the position which is to
* the left of the found item. This requires no code,
* bin_search did it already.
*/
/*
* So we have chosen a position in the current node which is
* an internal node. Now we calculate child block number by
* position in the node.
*/
block_number =
B_N_CHILD_NUM(bh, last_element->pe_position);
/*
* if we are going to read leaf nodes, try for read
* ahead as well
*/
if ((search_path->reada & PATH_READA) &&
node_level == DISK_LEAF_NODE_LEVEL + 1) {
int pos = last_element->pe_position;
int limit = B_NR_ITEMS(bh);
struct reiserfs_key *le_key;
if (search_path->reada & PATH_READA_BACK)
limit = 0;
while (reada_count < SEARCH_BY_KEY_READA) {
if (pos == limit)
break;
reada_blocks[reada_count++] =
B_N_CHILD_NUM(bh, pos);
if (search_path->reada & PATH_READA_BACK)
pos--;
else
pos++;
/*
* check to make sure we're in the same object
*/
le_key = internal_key(bh, pos);
if (le32_to_cpu(le_key->k_objectid) !=
key->on_disk_key.k_objectid) {
break;
}
}
}
}
}
/*
* Form the path to an item and position in this item which contains
* file byte defined by key. If there is no such item
* corresponding to the key, we point the path to the item with
* maximal key less than key, and *pos_in_item is set to one
* past the last entry/byte in the item. If searching for entry in a
* directory item, and it is not found, *pos_in_item is set to one
* entry more than the entry with maximal key which is less than the
* sought key.
*
* Note that if there is no entry in this same node which is one more,
* then we point to an imaginary entry. for direct items, the
* position is in units of bytes, for indirect items the position is
* in units of blocknr entries, for directory items the position is in
* units of directory entries.
*/
/* The function is NOT SCHEDULE-SAFE! */
int search_for_position_by_key(struct super_block *sb,
/* Key to search (cpu variable) */
const struct cpu_key *p_cpu_key,
/* Filled up by this function. */
struct treepath *search_path)
{
struct item_head *p_le_ih; /* pointer to on-disk structure */
int blk_size;
loff_t item_offset, offset;
struct reiserfs_dir_entry de;
int retval;
/* If searching for directory entry. */
if (is_direntry_cpu_key(p_cpu_key))
return search_by_entry_key(sb, p_cpu_key, search_path,
&de);
/* If not searching for directory entry. */
/* If item is found. */
retval = search_item(sb, p_cpu_key, search_path);
if (retval == IO_ERROR)
return retval;
if (retval == ITEM_FOUND) {
RFALSE(!ih_item_len
(item_head
(PATH_PLAST_BUFFER(search_path),
PATH_LAST_POSITION(search_path))),
"PAP-5165: item length equals zero");
pos_in_item(search_path) = 0;
return POSITION_FOUND;
}
RFALSE(!PATH_LAST_POSITION(search_path),
"PAP-5170: position equals zero");
/* Item is not found. Set path to the previous item. */
p_le_ih =
item_head(PATH_PLAST_BUFFER(search_path),
--PATH_LAST_POSITION(search_path));
blk_size = sb->s_blocksize;
if (comp_short_keys(&p_le_ih->ih_key, p_cpu_key))
return FILE_NOT_FOUND;
/* FIXME: quite ugly this far */
item_offset = le_ih_k_offset(p_le_ih);
offset = cpu_key_k_offset(p_cpu_key);
/* Needed byte is contained in the item pointed to by the path. */
if (item_offset <= offset &&
item_offset + op_bytes_number(p_le_ih, blk_size) > offset) {
pos_in_item(search_path) = offset - item_offset;
if (is_indirect_le_ih(p_le_ih)) {
pos_in_item(search_path) /= blk_size;
}
return POSITION_FOUND;
}
/*
* Needed byte is not contained in the item pointed to by the
* path. Set pos_in_item out of the item.
*/
if (is_indirect_le_ih(p_le_ih))
pos_in_item(search_path) =
ih_item_len(p_le_ih) / UNFM_P_SIZE;
else
pos_in_item(search_path) = ih_item_len(p_le_ih);
return POSITION_NOT_FOUND;
}
/* Compare given item and item pointed to by the path. */
int comp_items(const struct item_head *stored_ih, const struct treepath *path)
{
struct buffer_head *bh = PATH_PLAST_BUFFER(path);
struct item_head *ih;
/* Last buffer at the path is not in the tree. */
if (!B_IS_IN_TREE(bh))
return 1;
/* Last path position is invalid. */
if (PATH_LAST_POSITION(path) >= B_NR_ITEMS(bh))
return 1;
/* we need only to know, whether it is the same item */
ih = tp_item_head(path);
return memcmp(stored_ih, ih, IH_SIZE);
}
/* unformatted nodes are not logged anymore, ever. This is safe now */
#define held_by_others(bh) (atomic_read(&(bh)->b_count) > 1)
/* block can not be forgotten as it is in I/O or held by someone */
#define block_in_use(bh) (buffer_locked(bh) || (held_by_others(bh)))
/* prepare for delete or cut of direct item */
static inline int prepare_for_direct_item(struct treepath *path,
struct item_head *le_ih,
struct inode *inode,
loff_t new_file_length, int *cut_size)
{
loff_t round_len;
if (new_file_length == max_reiserfs_offset(inode)) {
/* item has to be deleted */
*cut_size = -(IH_SIZE + ih_item_len(le_ih));
return M_DELETE;
}
/* new file gets truncated */
if (get_inode_item_key_version(inode) == KEY_FORMAT_3_6) {
round_len = ROUND_UP(new_file_length);
/* this was new_file_length < le_ih ... */
if (round_len < le_ih_k_offset(le_ih)) {
*cut_size = -(IH_SIZE + ih_item_len(le_ih));
return M_DELETE; /* Delete this item. */
}
/* Calculate first position and size for cutting from item. */
pos_in_item(path) = round_len - (le_ih_k_offset(le_ih) - 1);
*cut_size = -(ih_item_len(le_ih) - pos_in_item(path));
return M_CUT; /* Cut from this item. */
}
/* old file: items may have any length */
if (new_file_length < le_ih_k_offset(le_ih)) {
*cut_size = -(IH_SIZE + ih_item_len(le_ih));
return M_DELETE; /* Delete this item. */
}
/* Calculate first position and size for cutting from item. */
*cut_size = -(ih_item_len(le_ih) -
(pos_in_item(path) =
new_file_length + 1 - le_ih_k_offset(le_ih)));
return M_CUT; /* Cut from this item. */
}
static inline int prepare_for_direntry_item(struct treepath *path,
struct item_head *le_ih,
struct inode *inode,
loff_t new_file_length,
int *cut_size)
{
if (le_ih_k_offset(le_ih) == DOT_OFFSET &&
new_file_length == max_reiserfs_offset(inode)) {
RFALSE(ih_entry_count(le_ih) != 2,
"PAP-5220: incorrect empty directory item (%h)", le_ih);
*cut_size = -(IH_SIZE + ih_item_len(le_ih));
/* Delete the directory item containing "." and ".." entry. */
return M_DELETE;
}
if (ih_entry_count(le_ih) == 1) {
/*
* Delete the directory item such as there is one record only
* in this item
*/
*cut_size = -(IH_SIZE + ih_item_len(le_ih));
return M_DELETE;
}
/* Cut one record from the directory item. */
*cut_size =
-(DEH_SIZE +
entry_length(get_last_bh(path), le_ih, pos_in_item(path)));
return M_CUT;