forked from torvalds/linux
-
Notifications
You must be signed in to change notification settings - Fork 17
/
xfs_da_btree.c
2471 lines (2330 loc) · 66.2 KB
/
xfs_da_btree.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) 2000-2005 Silicon Graphics, Inc.
* All Rights Reserved.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation.
*
* This program is distributed in the hope that it would be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include "xfs.h"
#include "xfs_fs.h"
#include "xfs_types.h"
#include "xfs_bit.h"
#include "xfs_log.h"
#include "xfs_inum.h"
#include "xfs_trans.h"
#include "xfs_sb.h"
#include "xfs_ag.h"
#include "xfs_dir2.h"
#include "xfs_dmapi.h"
#include "xfs_mount.h"
#include "xfs_da_btree.h"
#include "xfs_bmap_btree.h"
#include "xfs_alloc_btree.h"
#include "xfs_ialloc_btree.h"
#include "xfs_dir2_sf.h"
#include "xfs_attr_sf.h"
#include "xfs_dinode.h"
#include "xfs_inode.h"
#include "xfs_inode_item.h"
#include "xfs_alloc.h"
#include "xfs_btree.h"
#include "xfs_bmap.h"
#include "xfs_attr.h"
#include "xfs_attr_leaf.h"
#include "xfs_dir2_data.h"
#include "xfs_dir2_leaf.h"
#include "xfs_dir2_block.h"
#include "xfs_dir2_node.h"
#include "xfs_error.h"
/*
* xfs_da_btree.c
*
* Routines to implement directories as Btrees of hashed names.
*/
/*========================================================================
* Function prototypes for the kernel.
*========================================================================*/
/*
* Routines used for growing the Btree.
*/
STATIC int xfs_da_root_split(xfs_da_state_t *state,
xfs_da_state_blk_t *existing_root,
xfs_da_state_blk_t *new_child);
STATIC int xfs_da_node_split(xfs_da_state_t *state,
xfs_da_state_blk_t *existing_blk,
xfs_da_state_blk_t *split_blk,
xfs_da_state_blk_t *blk_to_add,
int treelevel,
int *result);
STATIC void xfs_da_node_rebalance(xfs_da_state_t *state,
xfs_da_state_blk_t *node_blk_1,
xfs_da_state_blk_t *node_blk_2);
STATIC void xfs_da_node_add(xfs_da_state_t *state,
xfs_da_state_blk_t *old_node_blk,
xfs_da_state_blk_t *new_node_blk);
/*
* Routines used for shrinking the Btree.
*/
STATIC int xfs_da_root_join(xfs_da_state_t *state,
xfs_da_state_blk_t *root_blk);
STATIC int xfs_da_node_toosmall(xfs_da_state_t *state, int *retval);
STATIC void xfs_da_node_remove(xfs_da_state_t *state,
xfs_da_state_blk_t *drop_blk);
STATIC void xfs_da_node_unbalance(xfs_da_state_t *state,
xfs_da_state_blk_t *src_node_blk,
xfs_da_state_blk_t *dst_node_blk);
/*
* Utility routines.
*/
STATIC uint xfs_da_node_lasthash(xfs_dabuf_t *bp, int *count);
STATIC int xfs_da_node_order(xfs_dabuf_t *node1_bp, xfs_dabuf_t *node2_bp);
STATIC xfs_dabuf_t *xfs_da_buf_make(int nbuf, xfs_buf_t **bps, inst_t *ra);
STATIC int xfs_da_blk_unlink(xfs_da_state_t *state,
xfs_da_state_blk_t *drop_blk,
xfs_da_state_blk_t *save_blk);
STATIC void xfs_da_state_kill_altpath(xfs_da_state_t *state);
/*========================================================================
* Routines used for growing the Btree.
*========================================================================*/
/*
* Create the initial contents of an intermediate node.
*/
int
xfs_da_node_create(xfs_da_args_t *args, xfs_dablk_t blkno, int level,
xfs_dabuf_t **bpp, int whichfork)
{
xfs_da_intnode_t *node;
xfs_dabuf_t *bp;
int error;
xfs_trans_t *tp;
tp = args->trans;
error = xfs_da_get_buf(tp, args->dp, blkno, -1, &bp, whichfork);
if (error)
return(error);
ASSERT(bp != NULL);
node = bp->data;
node->hdr.info.forw = 0;
node->hdr.info.back = 0;
node->hdr.info.magic = cpu_to_be16(XFS_DA_NODE_MAGIC);
node->hdr.info.pad = 0;
node->hdr.count = 0;
node->hdr.level = cpu_to_be16(level);
xfs_da_log_buf(tp, bp,
XFS_DA_LOGRANGE(node, &node->hdr, sizeof(node->hdr)));
*bpp = bp;
return(0);
}
/*
* Split a leaf node, rebalance, then possibly split
* intermediate nodes, rebalance, etc.
*/
int /* error */
xfs_da_split(xfs_da_state_t *state)
{
xfs_da_state_blk_t *oldblk, *newblk, *addblk;
xfs_da_intnode_t *node;
xfs_dabuf_t *bp;
int max, action, error, i;
/*
* Walk back up the tree splitting/inserting/adjusting as necessary.
* If we need to insert and there isn't room, split the node, then
* decide which fragment to insert the new block from below into.
* Note that we may split the root this way, but we need more fixup.
*/
max = state->path.active - 1;
ASSERT((max >= 0) && (max < XFS_DA_NODE_MAXDEPTH));
ASSERT(state->path.blk[max].magic == XFS_ATTR_LEAF_MAGIC ||
state->path.blk[max].magic == XFS_DIR2_LEAFN_MAGIC);
addblk = &state->path.blk[max]; /* initial dummy value */
for (i = max; (i >= 0) && addblk; state->path.active--, i--) {
oldblk = &state->path.blk[i];
newblk = &state->altpath.blk[i];
/*
* If a leaf node then
* Allocate a new leaf node, then rebalance across them.
* else if an intermediate node then
* We split on the last layer, must we split the node?
*/
switch (oldblk->magic) {
case XFS_ATTR_LEAF_MAGIC:
error = xfs_attr_leaf_split(state, oldblk, newblk);
if ((error != 0) && (error != ENOSPC)) {
return(error); /* GROT: attr is inconsistent */
}
if (!error) {
addblk = newblk;
break;
}
/*
* Entry wouldn't fit, split the leaf again.
*/
state->extravalid = 1;
if (state->inleaf) {
state->extraafter = 0; /* before newblk */
error = xfs_attr_leaf_split(state, oldblk,
&state->extrablk);
} else {
state->extraafter = 1; /* after newblk */
error = xfs_attr_leaf_split(state, newblk,
&state->extrablk);
}
if (error)
return(error); /* GROT: attr inconsistent */
addblk = newblk;
break;
case XFS_DIR2_LEAFN_MAGIC:
error = xfs_dir2_leafn_split(state, oldblk, newblk);
if (error)
return error;
addblk = newblk;
break;
case XFS_DA_NODE_MAGIC:
error = xfs_da_node_split(state, oldblk, newblk, addblk,
max - i, &action);
xfs_da_buf_done(addblk->bp);
addblk->bp = NULL;
if (error)
return(error); /* GROT: dir is inconsistent */
/*
* Record the newly split block for the next time thru?
*/
if (action)
addblk = newblk;
else
addblk = NULL;
break;
}
/*
* Update the btree to show the new hashval for this child.
*/
xfs_da_fixhashpath(state, &state->path);
/*
* If we won't need this block again, it's getting dropped
* from the active path by the loop control, so we need
* to mark it done now.
*/
if (i > 0 || !addblk)
xfs_da_buf_done(oldblk->bp);
}
if (!addblk)
return(0);
/*
* Split the root node.
*/
ASSERT(state->path.active == 0);
oldblk = &state->path.blk[0];
error = xfs_da_root_split(state, oldblk, addblk);
if (error) {
xfs_da_buf_done(oldblk->bp);
xfs_da_buf_done(addblk->bp);
addblk->bp = NULL;
return(error); /* GROT: dir is inconsistent */
}
/*
* Update pointers to the node which used to be block 0 and
* just got bumped because of the addition of a new root node.
* There might be three blocks involved if a double split occurred,
* and the original block 0 could be at any position in the list.
*/
node = oldblk->bp->data;
if (node->hdr.info.forw) {
if (be32_to_cpu(node->hdr.info.forw) == addblk->blkno) {
bp = addblk->bp;
} else {
ASSERT(state->extravalid);
bp = state->extrablk.bp;
}
node = bp->data;
node->hdr.info.back = cpu_to_be32(oldblk->blkno);
xfs_da_log_buf(state->args->trans, bp,
XFS_DA_LOGRANGE(node, &node->hdr.info,
sizeof(node->hdr.info)));
}
node = oldblk->bp->data;
if (node->hdr.info.back) {
if (be32_to_cpu(node->hdr.info.back) == addblk->blkno) {
bp = addblk->bp;
} else {
ASSERT(state->extravalid);
bp = state->extrablk.bp;
}
node = bp->data;
node->hdr.info.forw = cpu_to_be32(oldblk->blkno);
xfs_da_log_buf(state->args->trans, bp,
XFS_DA_LOGRANGE(node, &node->hdr.info,
sizeof(node->hdr.info)));
}
xfs_da_buf_done(oldblk->bp);
xfs_da_buf_done(addblk->bp);
addblk->bp = NULL;
return(0);
}
/*
* Split the root. We have to create a new root and point to the two
* parts (the split old root) that we just created. Copy block zero to
* the EOF, extending the inode in process.
*/
STATIC int /* error */
xfs_da_root_split(xfs_da_state_t *state, xfs_da_state_blk_t *blk1,
xfs_da_state_blk_t *blk2)
{
xfs_da_intnode_t *node, *oldroot;
xfs_da_args_t *args;
xfs_dablk_t blkno;
xfs_dabuf_t *bp;
int error, size;
xfs_inode_t *dp;
xfs_trans_t *tp;
xfs_mount_t *mp;
xfs_dir2_leaf_t *leaf;
/*
* Copy the existing (incorrect) block from the root node position
* to a free space somewhere.
*/
args = state->args;
ASSERT(args != NULL);
error = xfs_da_grow_inode(args, &blkno);
if (error)
return(error);
dp = args->dp;
tp = args->trans;
mp = state->mp;
error = xfs_da_get_buf(tp, dp, blkno, -1, &bp, args->whichfork);
if (error)
return(error);
ASSERT(bp != NULL);
node = bp->data;
oldroot = blk1->bp->data;
if (be16_to_cpu(oldroot->hdr.info.magic) == XFS_DA_NODE_MAGIC) {
size = (int)((char *)&oldroot->btree[be16_to_cpu(oldroot->hdr.count)] -
(char *)oldroot);
} else {
ASSERT(be16_to_cpu(oldroot->hdr.info.magic) == XFS_DIR2_LEAFN_MAGIC);
leaf = (xfs_dir2_leaf_t *)oldroot;
size = (int)((char *)&leaf->ents[be16_to_cpu(leaf->hdr.count)] -
(char *)leaf);
}
memcpy(node, oldroot, size);
xfs_da_log_buf(tp, bp, 0, size - 1);
xfs_da_buf_done(blk1->bp);
blk1->bp = bp;
blk1->blkno = blkno;
/*
* Set up the new root node.
*/
error = xfs_da_node_create(args,
(args->whichfork == XFS_DATA_FORK) ? mp->m_dirleafblk : 0,
be16_to_cpu(node->hdr.level) + 1, &bp, args->whichfork);
if (error)
return(error);
node = bp->data;
node->btree[0].hashval = cpu_to_be32(blk1->hashval);
node->btree[0].before = cpu_to_be32(blk1->blkno);
node->btree[1].hashval = cpu_to_be32(blk2->hashval);
node->btree[1].before = cpu_to_be32(blk2->blkno);
node->hdr.count = cpu_to_be16(2);
#ifdef DEBUG
if (be16_to_cpu(oldroot->hdr.info.magic) == XFS_DIR2_LEAFN_MAGIC) {
ASSERT(blk1->blkno >= mp->m_dirleafblk &&
blk1->blkno < mp->m_dirfreeblk);
ASSERT(blk2->blkno >= mp->m_dirleafblk &&
blk2->blkno < mp->m_dirfreeblk);
}
#endif
/* Header is already logged by xfs_da_node_create */
xfs_da_log_buf(tp, bp,
XFS_DA_LOGRANGE(node, node->btree,
sizeof(xfs_da_node_entry_t) * 2));
xfs_da_buf_done(bp);
return(0);
}
/*
* Split the node, rebalance, then add the new entry.
*/
STATIC int /* error */
xfs_da_node_split(xfs_da_state_t *state, xfs_da_state_blk_t *oldblk,
xfs_da_state_blk_t *newblk,
xfs_da_state_blk_t *addblk,
int treelevel, int *result)
{
xfs_da_intnode_t *node;
xfs_dablk_t blkno;
int newcount, error;
int useextra;
node = oldblk->bp->data;
ASSERT(be16_to_cpu(node->hdr.info.magic) == XFS_DA_NODE_MAGIC);
/*
* With V2 dirs the extra block is data or freespace.
*/
useextra = state->extravalid && state->args->whichfork == XFS_ATTR_FORK;
newcount = 1 + useextra;
/*
* Do we have to split the node?
*/
if ((be16_to_cpu(node->hdr.count) + newcount) > state->node_ents) {
/*
* Allocate a new node, add to the doubly linked chain of
* nodes, then move some of our excess entries into it.
*/
error = xfs_da_grow_inode(state->args, &blkno);
if (error)
return(error); /* GROT: dir is inconsistent */
error = xfs_da_node_create(state->args, blkno, treelevel,
&newblk->bp, state->args->whichfork);
if (error)
return(error); /* GROT: dir is inconsistent */
newblk->blkno = blkno;
newblk->magic = XFS_DA_NODE_MAGIC;
xfs_da_node_rebalance(state, oldblk, newblk);
error = xfs_da_blk_link(state, oldblk, newblk);
if (error)
return(error);
*result = 1;
} else {
*result = 0;
}
/*
* Insert the new entry(s) into the correct block
* (updating last hashval in the process).
*
* xfs_da_node_add() inserts BEFORE the given index,
* and as a result of using node_lookup_int() we always
* point to a valid entry (not after one), but a split
* operation always results in a new block whose hashvals
* FOLLOW the current block.
*
* If we had double-split op below us, then add the extra block too.
*/
node = oldblk->bp->data;
if (oldblk->index <= be16_to_cpu(node->hdr.count)) {
oldblk->index++;
xfs_da_node_add(state, oldblk, addblk);
if (useextra) {
if (state->extraafter)
oldblk->index++;
xfs_da_node_add(state, oldblk, &state->extrablk);
state->extravalid = 0;
}
} else {
newblk->index++;
xfs_da_node_add(state, newblk, addblk);
if (useextra) {
if (state->extraafter)
newblk->index++;
xfs_da_node_add(state, newblk, &state->extrablk);
state->extravalid = 0;
}
}
return(0);
}
/*
* Balance the btree elements between two intermediate nodes,
* usually one full and one empty.
*
* NOTE: if blk2 is empty, then it will get the upper half of blk1.
*/
STATIC void
xfs_da_node_rebalance(xfs_da_state_t *state, xfs_da_state_blk_t *blk1,
xfs_da_state_blk_t *blk2)
{
xfs_da_intnode_t *node1, *node2, *tmpnode;
xfs_da_node_entry_t *btree_s, *btree_d;
int count, tmp;
xfs_trans_t *tp;
node1 = blk1->bp->data;
node2 = blk2->bp->data;
/*
* Figure out how many entries need to move, and in which direction.
* Swap the nodes around if that makes it simpler.
*/
if ((be16_to_cpu(node1->hdr.count) > 0) && (be16_to_cpu(node2->hdr.count) > 0) &&
((be32_to_cpu(node2->btree[0].hashval) < be32_to_cpu(node1->btree[0].hashval)) ||
(be32_to_cpu(node2->btree[be16_to_cpu(node2->hdr.count)-1].hashval) <
be32_to_cpu(node1->btree[be16_to_cpu(node1->hdr.count)-1].hashval)))) {
tmpnode = node1;
node1 = node2;
node2 = tmpnode;
}
ASSERT(be16_to_cpu(node1->hdr.info.magic) == XFS_DA_NODE_MAGIC);
ASSERT(be16_to_cpu(node2->hdr.info.magic) == XFS_DA_NODE_MAGIC);
count = (be16_to_cpu(node1->hdr.count) - be16_to_cpu(node2->hdr.count)) / 2;
if (count == 0)
return;
tp = state->args->trans;
/*
* Two cases: high-to-low and low-to-high.
*/
if (count > 0) {
/*
* Move elements in node2 up to make a hole.
*/
if ((tmp = be16_to_cpu(node2->hdr.count)) > 0) {
tmp *= (uint)sizeof(xfs_da_node_entry_t);
btree_s = &node2->btree[0];
btree_d = &node2->btree[count];
memmove(btree_d, btree_s, tmp);
}
/*
* Move the req'd B-tree elements from high in node1 to
* low in node2.
*/
be16_add_cpu(&node2->hdr.count, count);
tmp = count * (uint)sizeof(xfs_da_node_entry_t);
btree_s = &node1->btree[be16_to_cpu(node1->hdr.count) - count];
btree_d = &node2->btree[0];
memcpy(btree_d, btree_s, tmp);
be16_add_cpu(&node1->hdr.count, -count);
} else {
/*
* Move the req'd B-tree elements from low in node2 to
* high in node1.
*/
count = -count;
tmp = count * (uint)sizeof(xfs_da_node_entry_t);
btree_s = &node2->btree[0];
btree_d = &node1->btree[be16_to_cpu(node1->hdr.count)];
memcpy(btree_d, btree_s, tmp);
be16_add_cpu(&node1->hdr.count, count);
xfs_da_log_buf(tp, blk1->bp,
XFS_DA_LOGRANGE(node1, btree_d, tmp));
/*
* Move elements in node2 down to fill the hole.
*/
tmp = be16_to_cpu(node2->hdr.count) - count;
tmp *= (uint)sizeof(xfs_da_node_entry_t);
btree_s = &node2->btree[count];
btree_d = &node2->btree[0];
memmove(btree_d, btree_s, tmp);
be16_add_cpu(&node2->hdr.count, -count);
}
/*
* Log header of node 1 and all current bits of node 2.
*/
xfs_da_log_buf(tp, blk1->bp,
XFS_DA_LOGRANGE(node1, &node1->hdr, sizeof(node1->hdr)));
xfs_da_log_buf(tp, blk2->bp,
XFS_DA_LOGRANGE(node2, &node2->hdr,
sizeof(node2->hdr) +
sizeof(node2->btree[0]) * be16_to_cpu(node2->hdr.count)));
/*
* Record the last hashval from each block for upward propagation.
* (note: don't use the swapped node pointers)
*/
node1 = blk1->bp->data;
node2 = blk2->bp->data;
blk1->hashval = be32_to_cpu(node1->btree[be16_to_cpu(node1->hdr.count)-1].hashval);
blk2->hashval = be32_to_cpu(node2->btree[be16_to_cpu(node2->hdr.count)-1].hashval);
/*
* Adjust the expected index for insertion.
*/
if (blk1->index >= be16_to_cpu(node1->hdr.count)) {
blk2->index = blk1->index - be16_to_cpu(node1->hdr.count);
blk1->index = be16_to_cpu(node1->hdr.count) + 1; /* make it invalid */
}
}
/*
* Add a new entry to an intermediate node.
*/
STATIC void
xfs_da_node_add(xfs_da_state_t *state, xfs_da_state_blk_t *oldblk,
xfs_da_state_blk_t *newblk)
{
xfs_da_intnode_t *node;
xfs_da_node_entry_t *btree;
int tmp;
xfs_mount_t *mp;
node = oldblk->bp->data;
mp = state->mp;
ASSERT(be16_to_cpu(node->hdr.info.magic) == XFS_DA_NODE_MAGIC);
ASSERT((oldblk->index >= 0) && (oldblk->index <= be16_to_cpu(node->hdr.count)));
ASSERT(newblk->blkno != 0);
if (state->args->whichfork == XFS_DATA_FORK)
ASSERT(newblk->blkno >= mp->m_dirleafblk &&
newblk->blkno < mp->m_dirfreeblk);
/*
* We may need to make some room before we insert the new node.
*/
tmp = 0;
btree = &node->btree[ oldblk->index ];
if (oldblk->index < be16_to_cpu(node->hdr.count)) {
tmp = (be16_to_cpu(node->hdr.count) - oldblk->index) * (uint)sizeof(*btree);
memmove(btree + 1, btree, tmp);
}
btree->hashval = cpu_to_be32(newblk->hashval);
btree->before = cpu_to_be32(newblk->blkno);
xfs_da_log_buf(state->args->trans, oldblk->bp,
XFS_DA_LOGRANGE(node, btree, tmp + sizeof(*btree)));
be16_add_cpu(&node->hdr.count, 1);
xfs_da_log_buf(state->args->trans, oldblk->bp,
XFS_DA_LOGRANGE(node, &node->hdr, sizeof(node->hdr)));
/*
* Copy the last hash value from the oldblk to propagate upwards.
*/
oldblk->hashval = be32_to_cpu(node->btree[be16_to_cpu(node->hdr.count)-1 ].hashval);
}
/*========================================================================
* Routines used for shrinking the Btree.
*========================================================================*/
/*
* Deallocate an empty leaf node, remove it from its parent,
* possibly deallocating that block, etc...
*/
int
xfs_da_join(xfs_da_state_t *state)
{
xfs_da_state_blk_t *drop_blk, *save_blk;
int action, error;
action = 0;
drop_blk = &state->path.blk[ state->path.active-1 ];
save_blk = &state->altpath.blk[ state->path.active-1 ];
ASSERT(state->path.blk[0].magic == XFS_DA_NODE_MAGIC);
ASSERT(drop_blk->magic == XFS_ATTR_LEAF_MAGIC ||
drop_blk->magic == XFS_DIR2_LEAFN_MAGIC);
/*
* Walk back up the tree joining/deallocating as necessary.
* When we stop dropping blocks, break out.
*/
for ( ; state->path.active >= 2; drop_blk--, save_blk--,
state->path.active--) {
/*
* See if we can combine the block with a neighbor.
* (action == 0) => no options, just leave
* (action == 1) => coalesce, then unlink
* (action == 2) => block empty, unlink it
*/
switch (drop_blk->magic) {
case XFS_ATTR_LEAF_MAGIC:
error = xfs_attr_leaf_toosmall(state, &action);
if (error)
return(error);
if (action == 0)
return(0);
xfs_attr_leaf_unbalance(state, drop_blk, save_blk);
break;
case XFS_DIR2_LEAFN_MAGIC:
error = xfs_dir2_leafn_toosmall(state, &action);
if (error)
return error;
if (action == 0)
return 0;
xfs_dir2_leafn_unbalance(state, drop_blk, save_blk);
break;
case XFS_DA_NODE_MAGIC:
/*
* Remove the offending node, fixup hashvals,
* check for a toosmall neighbor.
*/
xfs_da_node_remove(state, drop_blk);
xfs_da_fixhashpath(state, &state->path);
error = xfs_da_node_toosmall(state, &action);
if (error)
return(error);
if (action == 0)
return 0;
xfs_da_node_unbalance(state, drop_blk, save_blk);
break;
}
xfs_da_fixhashpath(state, &state->altpath);
error = xfs_da_blk_unlink(state, drop_blk, save_blk);
xfs_da_state_kill_altpath(state);
if (error)
return(error);
error = xfs_da_shrink_inode(state->args, drop_blk->blkno,
drop_blk->bp);
drop_blk->bp = NULL;
if (error)
return(error);
}
/*
* We joined all the way to the top. If it turns out that
* we only have one entry in the root, make the child block
* the new root.
*/
xfs_da_node_remove(state, drop_blk);
xfs_da_fixhashpath(state, &state->path);
error = xfs_da_root_join(state, &state->path.blk[0]);
return(error);
}
/*
* We have only one entry in the root. Copy the only remaining child of
* the old root to block 0 as the new root node.
*/
STATIC int
xfs_da_root_join(xfs_da_state_t *state, xfs_da_state_blk_t *root_blk)
{
xfs_da_intnode_t *oldroot;
/* REFERENCED */
xfs_da_blkinfo_t *blkinfo;
xfs_da_args_t *args;
xfs_dablk_t child;
xfs_dabuf_t *bp;
int error;
args = state->args;
ASSERT(args != NULL);
ASSERT(root_blk->magic == XFS_DA_NODE_MAGIC);
oldroot = root_blk->bp->data;
ASSERT(be16_to_cpu(oldroot->hdr.info.magic) == XFS_DA_NODE_MAGIC);
ASSERT(!oldroot->hdr.info.forw);
ASSERT(!oldroot->hdr.info.back);
/*
* If the root has more than one child, then don't do anything.
*/
if (be16_to_cpu(oldroot->hdr.count) > 1)
return(0);
/*
* Read in the (only) child block, then copy those bytes into
* the root block's buffer and free the original child block.
*/
child = be32_to_cpu(oldroot->btree[0].before);
ASSERT(child != 0);
error = xfs_da_read_buf(args->trans, args->dp, child, -1, &bp,
args->whichfork);
if (error)
return(error);
ASSERT(bp != NULL);
blkinfo = bp->data;
if (be16_to_cpu(oldroot->hdr.level) == 1) {
ASSERT(be16_to_cpu(blkinfo->magic) == XFS_DIR2_LEAFN_MAGIC ||
be16_to_cpu(blkinfo->magic) == XFS_ATTR_LEAF_MAGIC);
} else {
ASSERT(be16_to_cpu(blkinfo->magic) == XFS_DA_NODE_MAGIC);
}
ASSERT(!blkinfo->forw);
ASSERT(!blkinfo->back);
memcpy(root_blk->bp->data, bp->data, state->blocksize);
xfs_da_log_buf(args->trans, root_blk->bp, 0, state->blocksize - 1);
error = xfs_da_shrink_inode(args, child, bp);
return(error);
}
/*
* Check a node block and its neighbors to see if the block should be
* collapsed into one or the other neighbor. Always keep the block
* with the smaller block number.
* If the current block is over 50% full, don't try to join it, return 0.
* If the block is empty, fill in the state structure and return 2.
* If it can be collapsed, fill in the state structure and return 1.
* If nothing can be done, return 0.
*/
STATIC int
xfs_da_node_toosmall(xfs_da_state_t *state, int *action)
{
xfs_da_intnode_t *node;
xfs_da_state_blk_t *blk;
xfs_da_blkinfo_t *info;
int count, forward, error, retval, i;
xfs_dablk_t blkno;
xfs_dabuf_t *bp;
/*
* Check for the degenerate case of the block being over 50% full.
* If so, it's not worth even looking to see if we might be able
* to coalesce with a sibling.
*/
blk = &state->path.blk[ state->path.active-1 ];
info = blk->bp->data;
ASSERT(be16_to_cpu(info->magic) == XFS_DA_NODE_MAGIC);
node = (xfs_da_intnode_t *)info;
count = be16_to_cpu(node->hdr.count);
if (count > (state->node_ents >> 1)) {
*action = 0; /* blk over 50%, don't try to join */
return(0); /* blk over 50%, don't try to join */
}
/*
* Check for the degenerate case of the block being empty.
* If the block is empty, we'll simply delete it, no need to
* coalesce it with a sibling block. We choose (arbitrarily)
* to merge with the forward block unless it is NULL.
*/
if (count == 0) {
/*
* Make altpath point to the block we want to keep and
* path point to the block we want to drop (this one).
*/
forward = (info->forw != 0);
memcpy(&state->altpath, &state->path, sizeof(state->path));
error = xfs_da_path_shift(state, &state->altpath, forward,
0, &retval);
if (error)
return(error);
if (retval) {
*action = 0;
} else {
*action = 2;
}
return(0);
}
/*
* Examine each sibling block to see if we can coalesce with
* at least 25% free space to spare. We need to figure out
* whether to merge with the forward or the backward block.
* We prefer coalescing with the lower numbered sibling so as
* to shrink a directory over time.
*/
/* start with smaller blk num */
forward = (be32_to_cpu(info->forw) < be32_to_cpu(info->back));
for (i = 0; i < 2; forward = !forward, i++) {
if (forward)
blkno = be32_to_cpu(info->forw);
else
blkno = be32_to_cpu(info->back);
if (blkno == 0)
continue;
error = xfs_da_read_buf(state->args->trans, state->args->dp,
blkno, -1, &bp, state->args->whichfork);
if (error)
return(error);
ASSERT(bp != NULL);
node = (xfs_da_intnode_t *)info;
count = state->node_ents;
count -= state->node_ents >> 2;
count -= be16_to_cpu(node->hdr.count);
node = bp->data;
ASSERT(be16_to_cpu(node->hdr.info.magic) == XFS_DA_NODE_MAGIC);
count -= be16_to_cpu(node->hdr.count);
xfs_da_brelse(state->args->trans, bp);
if (count >= 0)
break; /* fits with at least 25% to spare */
}
if (i >= 2) {
*action = 0;
return(0);
}
/*
* Make altpath point to the block we want to keep (the lower
* numbered block) and path point to the block we want to drop.
*/
memcpy(&state->altpath, &state->path, sizeof(state->path));
if (blkno < blk->blkno) {
error = xfs_da_path_shift(state, &state->altpath, forward,
0, &retval);
if (error) {
return(error);
}
if (retval) {
*action = 0;
return(0);
}
} else {
error = xfs_da_path_shift(state, &state->path, forward,
0, &retval);
if (error) {
return(error);
}
if (retval) {
*action = 0;
return(0);
}
}
*action = 1;
return(0);
}
/*
* Walk back up the tree adjusting hash values as necessary,
* when we stop making changes, return.
*/
void
xfs_da_fixhashpath(xfs_da_state_t *state, xfs_da_state_path_t *path)
{
xfs_da_state_blk_t *blk;
xfs_da_intnode_t *node;
xfs_da_node_entry_t *btree;
xfs_dahash_t lasthash=0;
int level, count;
level = path->active-1;
blk = &path->blk[ level ];
switch (blk->magic) {
case XFS_ATTR_LEAF_MAGIC:
lasthash = xfs_attr_leaf_lasthash(blk->bp, &count);
if (count == 0)
return;
break;
case XFS_DIR2_LEAFN_MAGIC:
lasthash = xfs_dir2_leafn_lasthash(blk->bp, &count);
if (count == 0)
return;
break;
case XFS_DA_NODE_MAGIC:
lasthash = xfs_da_node_lasthash(blk->bp, &count);
if (count == 0)
return;
break;
}
for (blk--, level--; level >= 0; blk--, level--) {
node = blk->bp->data;
ASSERT(be16_to_cpu(node->hdr.info.magic) == XFS_DA_NODE_MAGIC);
btree = &node->btree[ blk->index ];
if (be32_to_cpu(btree->hashval) == lasthash)
break;
blk->hashval = lasthash;
btree->hashval = cpu_to_be32(lasthash);
xfs_da_log_buf(state->args->trans, blk->bp,
XFS_DA_LOGRANGE(node, btree, sizeof(*btree)));
lasthash = be32_to_cpu(node->btree[be16_to_cpu(node->hdr.count)-1].hashval);
}
}
/*
* Remove an entry from an intermediate node.
*/
STATIC void
xfs_da_node_remove(xfs_da_state_t *state, xfs_da_state_blk_t *drop_blk)
{
xfs_da_intnode_t *node;
xfs_da_node_entry_t *btree;
int tmp;
node = drop_blk->bp->data;
ASSERT(drop_blk->index < be16_to_cpu(node->hdr.count));
ASSERT(drop_blk->index >= 0);
/*
* Copy over the offending entry, or just zero it out.
*/
btree = &node->btree[drop_blk->index];
if (drop_blk->index < (be16_to_cpu(node->hdr.count)-1)) {
tmp = be16_to_cpu(node->hdr.count) - drop_blk->index - 1;
tmp *= (uint)sizeof(xfs_da_node_entry_t);
memmove(btree, btree + 1, tmp);
xfs_da_log_buf(state->args->trans, drop_blk->bp,
XFS_DA_LOGRANGE(node, btree, tmp));
btree = &node->btree[be16_to_cpu(node->hdr.count)-1];
}
memset((char *)btree, 0, sizeof(xfs_da_node_entry_t));
xfs_da_log_buf(state->args->trans, drop_blk->bp,
XFS_DA_LOGRANGE(node, btree, sizeof(*btree)));
be16_add_cpu(&node->hdr.count, -1);
xfs_da_log_buf(state->args->trans, drop_blk->bp,
XFS_DA_LOGRANGE(node, &node->hdr, sizeof(node->hdr)));
/*
* Copy the last hash value from the block to propagate upwards.
*/
btree--;
drop_blk->hashval = be32_to_cpu(btree->hashval);
}
/*
* Unbalance the btree elements between two intermediate nodes,
* move all Btree elements from one node into another.
*/
STATIC void
xfs_da_node_unbalance(xfs_da_state_t *state, xfs_da_state_blk_t *drop_blk,
xfs_da_state_blk_t *save_blk)
{
xfs_da_intnode_t *drop_node, *save_node;
xfs_da_node_entry_t *btree;
int tmp;
xfs_trans_t *tp;
drop_node = drop_blk->bp->data;
save_node = save_blk->bp->data;
ASSERT(be16_to_cpu(drop_node->hdr.info.magic) == XFS_DA_NODE_MAGIC);
ASSERT(be16_to_cpu(save_node->hdr.info.magic) == XFS_DA_NODE_MAGIC);
tp = state->args->trans;
/*
* If the dying block has lower hashvals, then move all the
* elements in the remaining block up to make a hole.
*/
if ((be32_to_cpu(drop_node->btree[0].hashval) < be32_to_cpu(save_node->btree[ 0 ].hashval)) ||
(be32_to_cpu(drop_node->btree[be16_to_cpu(drop_node->hdr.count)-1].hashval) <
be32_to_cpu(save_node->btree[be16_to_cpu(save_node->hdr.count)-1].hashval)))
{
btree = &save_node->btree[be16_to_cpu(drop_node->hdr.count)];