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1/*
2 * Copyright (c) 2000-2002,2005 Silicon Graphics, Inc.
3 * All Rights Reserved.
4 *
5 * This program is free software; you can redistribute it and/or
6 * modify it under the terms of the GNU General Public License as
7 * published by the Free Software Foundation.
8 *
9 * This program is distributed in the hope that it would be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
13 *
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, write the Free Software Foundation,
16 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
17 */
18#include "xfs.h"
19#include "xfs_fs.h"
20#include "xfs_shared.h"
21#include "xfs_format.h"
22#include "xfs_log_format.h"
23#include "xfs_trans_resv.h"
24#include "xfs_bit.h"
25#include "xfs_mount.h"
26#include "xfs_defer.h"
27#include "xfs_inode.h"
28#include "xfs_trans.h"
29#include "xfs_inode_item.h"
30#include "xfs_buf_item.h"
31#include "xfs_btree.h"
32#include "xfs_errortag.h"
33#include "xfs_error.h"
34#include "xfs_trace.h"
35#include "xfs_cksum.h"
36#include "xfs_alloc.h"
37#include "xfs_log.h"
38
39/*
40 * Cursor allocation zone.
41 */
42kmem_zone_t *xfs_btree_cur_zone;
43
44/*
45 * Btree magic numbers.
46 */
47static const uint32_t xfs_magics[2][XFS_BTNUM_MAX] = {
48 { XFS_ABTB_MAGIC, XFS_ABTC_MAGIC, 0, XFS_BMAP_MAGIC, XFS_IBT_MAGIC,
49 XFS_FIBT_MAGIC, 0 },
50 { XFS_ABTB_CRC_MAGIC, XFS_ABTC_CRC_MAGIC, XFS_RMAP_CRC_MAGIC,
51 XFS_BMAP_CRC_MAGIC, XFS_IBT_CRC_MAGIC, XFS_FIBT_CRC_MAGIC,
52 XFS_REFC_CRC_MAGIC }
53};
54
55uint32_t
56xfs_btree_magic(
57 int crc,
58 xfs_btnum_t btnum)
59{
60 uint32_t magic = xfs_magics[crc][btnum];
61
62 /* Ensure we asked for crc for crc-only magics. */
63 ASSERT(magic != 0);
64 return magic;
65}
66
67/*
68 * Check a long btree block header. Return the address of the failing check,
69 * or NULL if everything is ok.
70 */
71xfs_failaddr_t
72__xfs_btree_check_lblock(
73 struct xfs_btree_cur *cur,
74 struct xfs_btree_block *block,
75 int level,
76 struct xfs_buf *bp)
77{
78 struct xfs_mount *mp = cur->bc_mp;
79 xfs_btnum_t btnum = cur->bc_btnum;
80 int crc = xfs_sb_version_hascrc(&mp->m_sb);
81
82 if (crc) {
83 if (!uuid_equal(&block->bb_u.l.bb_uuid, &mp->m_sb.sb_meta_uuid))
84 return __this_address;
85 if (block->bb_u.l.bb_blkno !=
86 cpu_to_be64(bp ? bp->b_bn : XFS_BUF_DADDR_NULL))
87 return __this_address;
88 if (block->bb_u.l.bb_pad != cpu_to_be32(0))
89 return __this_address;
90 }
91
92 if (be32_to_cpu(block->bb_magic) != xfs_btree_magic(crc, btnum))
93 return __this_address;
94 if (be16_to_cpu(block->bb_level) != level)
95 return __this_address;
96 if (be16_to_cpu(block->bb_numrecs) >
97 cur->bc_ops->get_maxrecs(cur, level))
98 return __this_address;
99 if (block->bb_u.l.bb_leftsib != cpu_to_be64(NULLFSBLOCK) &&
100 !xfs_btree_check_lptr(cur, be64_to_cpu(block->bb_u.l.bb_leftsib),
101 level + 1))
102 return __this_address;
103 if (block->bb_u.l.bb_rightsib != cpu_to_be64(NULLFSBLOCK) &&
104 !xfs_btree_check_lptr(cur, be64_to_cpu(block->bb_u.l.bb_rightsib),
105 level + 1))
106 return __this_address;
107
108 return NULL;
109}
110
111/* Check a long btree block header. */
112static int
113xfs_btree_check_lblock(
114 struct xfs_btree_cur *cur,
115 struct xfs_btree_block *block,
116 int level,
117 struct xfs_buf *bp)
118{
119 struct xfs_mount *mp = cur->bc_mp;
120 xfs_failaddr_t fa;
121
122 fa = __xfs_btree_check_lblock(cur, block, level, bp);
123 if (unlikely(XFS_TEST_ERROR(fa != NULL, mp,
124 XFS_ERRTAG_BTREE_CHECK_LBLOCK))) {
125 if (bp)
126 trace_xfs_btree_corrupt(bp, _RET_IP_);
127 XFS_ERROR_REPORT(__func__, XFS_ERRLEVEL_LOW, mp);
128 return -EFSCORRUPTED;
129 }
130 return 0;
131}
132
133/*
134 * Check a short btree block header. Return the address of the failing check,
135 * or NULL if everything is ok.
136 */
137xfs_failaddr_t
138__xfs_btree_check_sblock(
139 struct xfs_btree_cur *cur,
140 struct xfs_btree_block *block,
141 int level,
142 struct xfs_buf *bp)
143{
144 struct xfs_mount *mp = cur->bc_mp;
145 xfs_btnum_t btnum = cur->bc_btnum;
146 int crc = xfs_sb_version_hascrc(&mp->m_sb);
147
148 if (crc) {
149 if (!uuid_equal(&block->bb_u.s.bb_uuid, &mp->m_sb.sb_meta_uuid))
150 return __this_address;
151 if (block->bb_u.s.bb_blkno !=
152 cpu_to_be64(bp ? bp->b_bn : XFS_BUF_DADDR_NULL))
153 return __this_address;
154 }
155
156 if (be32_to_cpu(block->bb_magic) != xfs_btree_magic(crc, btnum))
157 return __this_address;
158 if (be16_to_cpu(block->bb_level) != level)
159 return __this_address;
160 if (be16_to_cpu(block->bb_numrecs) >
161 cur->bc_ops->get_maxrecs(cur, level))
162 return __this_address;
163 if (block->bb_u.s.bb_leftsib != cpu_to_be32(NULLAGBLOCK) &&
164 !xfs_btree_check_sptr(cur, be32_to_cpu(block->bb_u.s.bb_leftsib),
165 level + 1))
166 return __this_address;
167 if (block->bb_u.s.bb_rightsib != cpu_to_be32(NULLAGBLOCK) &&
168 !xfs_btree_check_sptr(cur, be32_to_cpu(block->bb_u.s.bb_rightsib),
169 level + 1))
170 return __this_address;
171
172 return NULL;
173}
174
175/* Check a short btree block header. */
176STATIC int
177xfs_btree_check_sblock(
178 struct xfs_btree_cur *cur,
179 struct xfs_btree_block *block,
180 int level,
181 struct xfs_buf *bp)
182{
183 struct xfs_mount *mp = cur->bc_mp;
184 xfs_failaddr_t fa;
185
186 fa = __xfs_btree_check_sblock(cur, block, level, bp);
187 if (unlikely(XFS_TEST_ERROR(fa != NULL, mp,
188 XFS_ERRTAG_BTREE_CHECK_SBLOCK))) {
189 if (bp)
190 trace_xfs_btree_corrupt(bp, _RET_IP_);
191 XFS_ERROR_REPORT(__func__, XFS_ERRLEVEL_LOW, mp);
192 return -EFSCORRUPTED;
193 }
194 return 0;
195}
196
197/*
198 * Debug routine: check that block header is ok.
199 */
200int
201xfs_btree_check_block(
202 struct xfs_btree_cur *cur, /* btree cursor */
203 struct xfs_btree_block *block, /* generic btree block pointer */
204 int level, /* level of the btree block */
205 struct xfs_buf *bp) /* buffer containing block, if any */
206{
207 if (cur->bc_flags & XFS_BTREE_LONG_PTRS)
208 return xfs_btree_check_lblock(cur, block, level, bp);
209 else
210 return xfs_btree_check_sblock(cur, block, level, bp);
211}
212
213/* Check that this long pointer is valid and points within the fs. */
214bool
215xfs_btree_check_lptr(
216 struct xfs_btree_cur *cur,
217 xfs_fsblock_t fsbno,
218 int level)
219{
220 if (level <= 0)
221 return false;
222 return xfs_verify_fsbno(cur->bc_mp, fsbno);
223}
224
225/* Check that this short pointer is valid and points within the AG. */
226bool
227xfs_btree_check_sptr(
228 struct xfs_btree_cur *cur,
229 xfs_agblock_t agbno,
230 int level)
231{
232 if (level <= 0)
233 return false;
234 return xfs_verify_agbno(cur->bc_mp, cur->bc_private.a.agno, agbno);
235}
236
237#ifdef DEBUG
238/*
239 * Check that a given (indexed) btree pointer at a certain level of a
240 * btree is valid and doesn't point past where it should.
241 */
242static int
243xfs_btree_check_ptr(
244 struct xfs_btree_cur *cur,
245 union xfs_btree_ptr *ptr,
246 int index,
247 int level)
248{
249 if (cur->bc_flags & XFS_BTREE_LONG_PTRS) {
250 XFS_WANT_CORRUPTED_RETURN(cur->bc_mp,
251 xfs_btree_check_lptr(cur,
252 be64_to_cpu((&ptr->l)[index]), level));
253 } else {
254 XFS_WANT_CORRUPTED_RETURN(cur->bc_mp,
255 xfs_btree_check_sptr(cur,
256 be32_to_cpu((&ptr->s)[index]), level));
257 }
258
259 return 0;
260}
261#endif
262
263/*
264 * Calculate CRC on the whole btree block and stuff it into the
265 * long-form btree header.
266 *
267 * Prior to calculting the CRC, pull the LSN out of the buffer log item and put
268 * it into the buffer so recovery knows what the last modification was that made
269 * it to disk.
270 */
271void
272xfs_btree_lblock_calc_crc(
273 struct xfs_buf *bp)
274{
275 struct xfs_btree_block *block = XFS_BUF_TO_BLOCK(bp);
276 struct xfs_buf_log_item *bip = bp->b_log_item;
277
278 if (!xfs_sb_version_hascrc(&bp->b_target->bt_mount->m_sb))
279 return;
280 if (bip)
281 block->bb_u.l.bb_lsn = cpu_to_be64(bip->bli_item.li_lsn);
282 xfs_buf_update_cksum(bp, XFS_BTREE_LBLOCK_CRC_OFF);
283}
284
285bool
286xfs_btree_lblock_verify_crc(
287 struct xfs_buf *bp)
288{
289 struct xfs_btree_block *block = XFS_BUF_TO_BLOCK(bp);
290 struct xfs_mount *mp = bp->b_target->bt_mount;
291
292 if (xfs_sb_version_hascrc(&mp->m_sb)) {
293 if (!xfs_log_check_lsn(mp, be64_to_cpu(block->bb_u.l.bb_lsn)))
294 return false;
295 return xfs_buf_verify_cksum(bp, XFS_BTREE_LBLOCK_CRC_OFF);
296 }
297
298 return true;
299}
300
301/*
302 * Calculate CRC on the whole btree block and stuff it into the
303 * short-form btree header.
304 *
305 * Prior to calculting the CRC, pull the LSN out of the buffer log item and put
306 * it into the buffer so recovery knows what the last modification was that made
307 * it to disk.
308 */
309void
310xfs_btree_sblock_calc_crc(
311 struct xfs_buf *bp)
312{
313 struct xfs_btree_block *block = XFS_BUF_TO_BLOCK(bp);
314 struct xfs_buf_log_item *bip = bp->b_log_item;
315
316 if (!xfs_sb_version_hascrc(&bp->b_target->bt_mount->m_sb))
317 return;
318 if (bip)
319 block->bb_u.s.bb_lsn = cpu_to_be64(bip->bli_item.li_lsn);
320 xfs_buf_update_cksum(bp, XFS_BTREE_SBLOCK_CRC_OFF);
321}
322
323bool
324xfs_btree_sblock_verify_crc(
325 struct xfs_buf *bp)
326{
327 struct xfs_btree_block *block = XFS_BUF_TO_BLOCK(bp);
328 struct xfs_mount *mp = bp->b_target->bt_mount;
329
330 if (xfs_sb_version_hascrc(&mp->m_sb)) {
331 if (!xfs_log_check_lsn(mp, be64_to_cpu(block->bb_u.s.bb_lsn)))
332 return __this_address;
333 return xfs_buf_verify_cksum(bp, XFS_BTREE_SBLOCK_CRC_OFF);
334 }
335
336 return true;
337}
338
339static int
340xfs_btree_free_block(
341 struct xfs_btree_cur *cur,
342 struct xfs_buf *bp)
343{
344 int error;
345
346 error = cur->bc_ops->free_block(cur, bp);
347 if (!error) {
348 xfs_trans_binval(cur->bc_tp, bp);
349 XFS_BTREE_STATS_INC(cur, free);
350 }
351 return error;
352}
353
354/*
355 * Delete the btree cursor.
356 */
357void
358xfs_btree_del_cursor(
359 xfs_btree_cur_t *cur, /* btree cursor */
360 int error) /* del because of error */
361{
362 int i; /* btree level */
363
364 /*
365 * Clear the buffer pointers, and release the buffers.
366 * If we're doing this in the face of an error, we
367 * need to make sure to inspect all of the entries
368 * in the bc_bufs array for buffers to be unlocked.
369 * This is because some of the btree code works from
370 * level n down to 0, and if we get an error along
371 * the way we won't have initialized all the entries
372 * down to 0.
373 */
374 for (i = 0; i < cur->bc_nlevels; i++) {
375 if (cur->bc_bufs[i])
376 xfs_trans_brelse(cur->bc_tp, cur->bc_bufs[i]);
377 else if (!error)
378 break;
379 }
380 /*
381 * Can't free a bmap cursor without having dealt with the
382 * allocated indirect blocks' accounting.
383 */
384 ASSERT(cur->bc_btnum != XFS_BTNUM_BMAP ||
385 cur->bc_private.b.allocated == 0);
386 /*
387 * Free the cursor.
388 */
389 kmem_zone_free(xfs_btree_cur_zone, cur);
390}
391
392/*
393 * Duplicate the btree cursor.
394 * Allocate a new one, copy the record, re-get the buffers.
395 */
396int /* error */
397xfs_btree_dup_cursor(
398 xfs_btree_cur_t *cur, /* input cursor */
399 xfs_btree_cur_t **ncur) /* output cursor */
400{
401 xfs_buf_t *bp; /* btree block's buffer pointer */
402 int error; /* error return value */
403 int i; /* level number of btree block */
404 xfs_mount_t *mp; /* mount structure for filesystem */
405 xfs_btree_cur_t *new; /* new cursor value */
406 xfs_trans_t *tp; /* transaction pointer, can be NULL */
407
408 tp = cur->bc_tp;
409 mp = cur->bc_mp;
410
411 /*
412 * Allocate a new cursor like the old one.
413 */
414 new = cur->bc_ops->dup_cursor(cur);
415
416 /*
417 * Copy the record currently in the cursor.
418 */
419 new->bc_rec = cur->bc_rec;
420
421 /*
422 * For each level current, re-get the buffer and copy the ptr value.
423 */
424 for (i = 0; i < new->bc_nlevels; i++) {
425 new->bc_ptrs[i] = cur->bc_ptrs[i];
426 new->bc_ra[i] = cur->bc_ra[i];
427 bp = cur->bc_bufs[i];
428 if (bp) {
429 error = xfs_trans_read_buf(mp, tp, mp->m_ddev_targp,
430 XFS_BUF_ADDR(bp), mp->m_bsize,
431 0, &bp,
432 cur->bc_ops->buf_ops);
433 if (error) {
434 xfs_btree_del_cursor(new, error);
435 *ncur = NULL;
436 return error;
437 }
438 }
439 new->bc_bufs[i] = bp;
440 }
441 *ncur = new;
442 return 0;
443}
444
445/*
446 * XFS btree block layout and addressing:
447 *
448 * There are two types of blocks in the btree: leaf and non-leaf blocks.
449 *
450 * The leaf record start with a header then followed by records containing
451 * the values. A non-leaf block also starts with the same header, and
452 * then first contains lookup keys followed by an equal number of pointers
453 * to the btree blocks at the previous level.
454 *
455 * +--------+-------+-------+-------+-------+-------+-------+
456 * Leaf: | header | rec 1 | rec 2 | rec 3 | rec 4 | rec 5 | rec N |
457 * +--------+-------+-------+-------+-------+-------+-------+
458 *
459 * +--------+-------+-------+-------+-------+-------+-------+
460 * Non-Leaf: | header | key 1 | key 2 | key N | ptr 1 | ptr 2 | ptr N |
461 * +--------+-------+-------+-------+-------+-------+-------+
462 *
463 * The header is called struct xfs_btree_block for reasons better left unknown
464 * and comes in different versions for short (32bit) and long (64bit) block
465 * pointers. The record and key structures are defined by the btree instances
466 * and opaque to the btree core. The block pointers are simple disk endian
467 * integers, available in a short (32bit) and long (64bit) variant.
468 *
469 * The helpers below calculate the offset of a given record, key or pointer
470 * into a btree block (xfs_btree_*_offset) or return a pointer to the given
471 * record, key or pointer (xfs_btree_*_addr). Note that all addressing
472 * inside the btree block is done using indices starting at one, not zero!
473 *
474 * If XFS_BTREE_OVERLAPPING is set, then this btree supports keys containing
475 * overlapping intervals. In such a tree, records are still sorted lowest to
476 * highest and indexed by the smallest key value that refers to the record.
477 * However, nodes are different: each pointer has two associated keys -- one
478 * indexing the lowest key available in the block(s) below (the same behavior
479 * as the key in a regular btree) and another indexing the highest key
480 * available in the block(s) below. Because records are /not/ sorted by the
481 * highest key, all leaf block updates require us to compute the highest key
482 * that matches any record in the leaf and to recursively update the high keys
483 * in the nodes going further up in the tree, if necessary. Nodes look like
484 * this:
485 *
486 * +--------+-----+-----+-----+-----+-----+-------+-------+-----+
487 * Non-Leaf: | header | lo1 | hi1 | lo2 | hi2 | ... | ptr 1 | ptr 2 | ... |
488 * +--------+-----+-----+-----+-----+-----+-------+-------+-----+
489 *
490 * To perform an interval query on an overlapped tree, perform the usual
491 * depth-first search and use the low and high keys to decide if we can skip
492 * that particular node. If a leaf node is reached, return the records that
493 * intersect the interval. Note that an interval query may return numerous
494 * entries. For a non-overlapped tree, simply search for the record associated
495 * with the lowest key and iterate forward until a non-matching record is
496 * found. Section 14.3 ("Interval Trees") of _Introduction to Algorithms_ by
497 * Cormen, Leiserson, Rivest, and Stein (2nd or 3rd ed. only) discuss this in
498 * more detail.
499 *
500 * Why do we care about overlapping intervals? Let's say you have a bunch of
501 * reverse mapping records on a reflink filesystem:
502 *
503 * 1: +- file A startblock B offset C length D -----------+
504 * 2: +- file E startblock F offset G length H --------------+
505 * 3: +- file I startblock F offset J length K --+
506 * 4: +- file L... --+
507 *
508 * Now say we want to map block (B+D) into file A at offset (C+D). Ideally,
509 * we'd simply increment the length of record 1. But how do we find the record
510 * that ends at (B+D-1) (i.e. record 1)? A LE lookup of (B+D-1) would return
511 * record 3 because the keys are ordered first by startblock. An interval
512 * query would return records 1 and 2 because they both overlap (B+D-1), and
513 * from that we can pick out record 1 as the appropriate left neighbor.
514 *
515 * In the non-overlapped case you can do a LE lookup and decrement the cursor
516 * because a record's interval must end before the next record.
517 */
518
519/*
520 * Return size of the btree block header for this btree instance.
521 */
522static inline size_t xfs_btree_block_len(struct xfs_btree_cur *cur)
523{
524 if (cur->bc_flags & XFS_BTREE_LONG_PTRS) {
525 if (cur->bc_flags & XFS_BTREE_CRC_BLOCKS)
526 return XFS_BTREE_LBLOCK_CRC_LEN;
527 return XFS_BTREE_LBLOCK_LEN;
528 }
529 if (cur->bc_flags & XFS_BTREE_CRC_BLOCKS)
530 return XFS_BTREE_SBLOCK_CRC_LEN;
531 return XFS_BTREE_SBLOCK_LEN;
532}
533
534/*
535 * Return size of btree block pointers for this btree instance.
536 */
537static inline size_t xfs_btree_ptr_len(struct xfs_btree_cur *cur)
538{
539 return (cur->bc_flags & XFS_BTREE_LONG_PTRS) ?
540 sizeof(__be64) : sizeof(__be32);
541}
542
543/*
544 * Calculate offset of the n-th record in a btree block.
545 */
546STATIC size_t
547xfs_btree_rec_offset(
548 struct xfs_btree_cur *cur,
549 int n)
550{
551 return xfs_btree_block_len(cur) +
552 (n - 1) * cur->bc_ops->rec_len;
553}
554
555/*
556 * Calculate offset of the n-th key in a btree block.
557 */
558STATIC size_t
559xfs_btree_key_offset(
560 struct xfs_btree_cur *cur,
561 int n)
562{
563 return xfs_btree_block_len(cur) +
564 (n - 1) * cur->bc_ops->key_len;
565}
566
567/*
568 * Calculate offset of the n-th high key in a btree block.
569 */
570STATIC size_t
571xfs_btree_high_key_offset(
572 struct xfs_btree_cur *cur,
573 int n)
574{
575 return xfs_btree_block_len(cur) +
576 (n - 1) * cur->bc_ops->key_len + (cur->bc_ops->key_len / 2);
577}
578
579/*
580 * Calculate offset of the n-th block pointer in a btree block.
581 */
582STATIC size_t
583xfs_btree_ptr_offset(
584 struct xfs_btree_cur *cur,
585 int n,
586 int level)
587{
588 return xfs_btree_block_len(cur) +
589 cur->bc_ops->get_maxrecs(cur, level) * cur->bc_ops->key_len +
590 (n - 1) * xfs_btree_ptr_len(cur);
591}
592
593/*
594 * Return a pointer to the n-th record in the btree block.
595 */
596union xfs_btree_rec *
597xfs_btree_rec_addr(
598 struct xfs_btree_cur *cur,
599 int n,
600 struct xfs_btree_block *block)
601{
602 return (union xfs_btree_rec *)
603 ((char *)block + xfs_btree_rec_offset(cur, n));
604}
605
606/*
607 * Return a pointer to the n-th key in the btree block.
608 */
609union xfs_btree_key *
610xfs_btree_key_addr(
611 struct xfs_btree_cur *cur,
612 int n,
613 struct xfs_btree_block *block)
614{
615 return (union xfs_btree_key *)
616 ((char *)block + xfs_btree_key_offset(cur, n));
617}
618
619/*
620 * Return a pointer to the n-th high key in the btree block.
621 */
622union xfs_btree_key *
623xfs_btree_high_key_addr(
624 struct xfs_btree_cur *cur,
625 int n,
626 struct xfs_btree_block *block)
627{
628 return (union xfs_btree_key *)
629 ((char *)block + xfs_btree_high_key_offset(cur, n));
630}
631
632/*
633 * Return a pointer to the n-th block pointer in the btree block.
634 */
635union xfs_btree_ptr *
636xfs_btree_ptr_addr(
637 struct xfs_btree_cur *cur,
638 int n,
639 struct xfs_btree_block *block)
640{
641 int level = xfs_btree_get_level(block);
642
643 ASSERT(block->bb_level != 0);
644
645 return (union xfs_btree_ptr *)
646 ((char *)block + xfs_btree_ptr_offset(cur, n, level));
647}
648
649/*
650 * Get the root block which is stored in the inode.
651 *
652 * For now this btree implementation assumes the btree root is always
653 * stored in the if_broot field of an inode fork.
654 */
655STATIC struct xfs_btree_block *
656xfs_btree_get_iroot(
657 struct xfs_btree_cur *cur)
658{
659 struct xfs_ifork *ifp;
660
661 ifp = XFS_IFORK_PTR(cur->bc_private.b.ip, cur->bc_private.b.whichfork);
662 return (struct xfs_btree_block *)ifp->if_broot;
663}
664
665/*
666 * Retrieve the block pointer from the cursor at the given level.
667 * This may be an inode btree root or from a buffer.
668 */
669struct xfs_btree_block * /* generic btree block pointer */
670xfs_btree_get_block(
671 struct xfs_btree_cur *cur, /* btree cursor */
672 int level, /* level in btree */
673 struct xfs_buf **bpp) /* buffer containing the block */
674{
675 if ((cur->bc_flags & XFS_BTREE_ROOT_IN_INODE) &&
676 (level == cur->bc_nlevels - 1)) {
677 *bpp = NULL;
678 return xfs_btree_get_iroot(cur);
679 }
680
681 *bpp = cur->bc_bufs[level];
682 return XFS_BUF_TO_BLOCK(*bpp);
683}
684
685/*
686 * Get a buffer for the block, return it with no data read.
687 * Long-form addressing.
688 */
689xfs_buf_t * /* buffer for fsbno */
690xfs_btree_get_bufl(
691 xfs_mount_t *mp, /* file system mount point */
692 xfs_trans_t *tp, /* transaction pointer */
693 xfs_fsblock_t fsbno, /* file system block number */
694 uint lock) /* lock flags for get_buf */
695{
696 xfs_daddr_t d; /* real disk block address */
697
698 ASSERT(fsbno != NULLFSBLOCK);
699 d = XFS_FSB_TO_DADDR(mp, fsbno);
700 return xfs_trans_get_buf(tp, mp->m_ddev_targp, d, mp->m_bsize, lock);
701}
702
703/*
704 * Get a buffer for the block, return it with no data read.
705 * Short-form addressing.
706 */
707xfs_buf_t * /* buffer for agno/agbno */
708xfs_btree_get_bufs(
709 xfs_mount_t *mp, /* file system mount point */
710 xfs_trans_t *tp, /* transaction pointer */
711 xfs_agnumber_t agno, /* allocation group number */
712 xfs_agblock_t agbno, /* allocation group block number */
713 uint lock) /* lock flags for get_buf */
714{
715 xfs_daddr_t d; /* real disk block address */
716
717 ASSERT(agno != NULLAGNUMBER);
718 ASSERT(agbno != NULLAGBLOCK);
719 d = XFS_AGB_TO_DADDR(mp, agno, agbno);
720 return xfs_trans_get_buf(tp, mp->m_ddev_targp, d, mp->m_bsize, lock);
721}
722
723/*
724 * Check for the cursor referring to the last block at the given level.
725 */
726int /* 1=is last block, 0=not last block */
727xfs_btree_islastblock(
728 xfs_btree_cur_t *cur, /* btree cursor */
729 int level) /* level to check */
730{
731 struct xfs_btree_block *block; /* generic btree block pointer */
732 xfs_buf_t *bp; /* buffer containing block */
733
734 block = xfs_btree_get_block(cur, level, &bp);
735 xfs_btree_check_block(cur, block, level, bp);
736 if (cur->bc_flags & XFS_BTREE_LONG_PTRS)
737 return block->bb_u.l.bb_rightsib == cpu_to_be64(NULLFSBLOCK);
738 else
739 return block->bb_u.s.bb_rightsib == cpu_to_be32(NULLAGBLOCK);
740}
741
742/*
743 * Change the cursor to point to the first record at the given level.
744 * Other levels are unaffected.
745 */
746STATIC int /* success=1, failure=0 */
747xfs_btree_firstrec(
748 xfs_btree_cur_t *cur, /* btree cursor */
749 int level) /* level to change */
750{
751 struct xfs_btree_block *block; /* generic btree block pointer */
752 xfs_buf_t *bp; /* buffer containing block */
753
754 /*
755 * Get the block pointer for this level.
756 */
757 block = xfs_btree_get_block(cur, level, &bp);
758 if (xfs_btree_check_block(cur, block, level, bp))
759 return 0;
760 /*
761 * It's empty, there is no such record.
762 */
763 if (!block->bb_numrecs)
764 return 0;
765 /*
766 * Set the ptr value to 1, that's the first record/key.
767 */
768 cur->bc_ptrs[level] = 1;
769 return 1;
770}
771
772/*
773 * Change the cursor to point to the last record in the current block
774 * at the given level. Other levels are unaffected.
775 */
776STATIC int /* success=1, failure=0 */
777xfs_btree_lastrec(
778 xfs_btree_cur_t *cur, /* btree cursor */
779 int level) /* level to change */
780{
781 struct xfs_btree_block *block; /* generic btree block pointer */
782 xfs_buf_t *bp; /* buffer containing block */
783
784 /*
785 * Get the block pointer for this level.
786 */
787 block = xfs_btree_get_block(cur, level, &bp);
788 if (xfs_btree_check_block(cur, block, level, bp))
789 return 0;
790 /*
791 * It's empty, there is no such record.
792 */
793 if (!block->bb_numrecs)
794 return 0;
795 /*
796 * Set the ptr value to numrecs, that's the last record/key.
797 */
798 cur->bc_ptrs[level] = be16_to_cpu(block->bb_numrecs);
799 return 1;
800}
801
802/*
803 * Compute first and last byte offsets for the fields given.
804 * Interprets the offsets table, which contains struct field offsets.
805 */
806void
807xfs_btree_offsets(
808 int64_t fields, /* bitmask of fields */
809 const short *offsets, /* table of field offsets */
810 int nbits, /* number of bits to inspect */
811 int *first, /* output: first byte offset */
812 int *last) /* output: last byte offset */
813{
814 int i; /* current bit number */
815 int64_t imask; /* mask for current bit number */
816
817 ASSERT(fields != 0);
818 /*
819 * Find the lowest bit, so the first byte offset.
820 */
821 for (i = 0, imask = 1LL; ; i++, imask <<= 1) {
822 if (imask & fields) {
823 *first = offsets[i];
824 break;
825 }
826 }
827 /*
828 * Find the highest bit, so the last byte offset.
829 */
830 for (i = nbits - 1, imask = 1LL << i; ; i--, imask >>= 1) {
831 if (imask & fields) {
832 *last = offsets[i + 1] - 1;
833 break;
834 }
835 }
836}
837
838/*
839 * Get a buffer for the block, return it read in.
840 * Long-form addressing.
841 */
842int
843xfs_btree_read_bufl(
844 struct xfs_mount *mp, /* file system mount point */
845 struct xfs_trans *tp, /* transaction pointer */
846 xfs_fsblock_t fsbno, /* file system block number */
847 uint lock, /* lock flags for read_buf */
848 struct xfs_buf **bpp, /* buffer for fsbno */
849 int refval, /* ref count value for buffer */
850 const struct xfs_buf_ops *ops)
851{
852 struct xfs_buf *bp; /* return value */
853 xfs_daddr_t d; /* real disk block address */
854 int error;
855
856 if (!xfs_verify_fsbno(mp, fsbno))
857 return -EFSCORRUPTED;
858 d = XFS_FSB_TO_DADDR(mp, fsbno);
859 error = xfs_trans_read_buf(mp, tp, mp->m_ddev_targp, d,
860 mp->m_bsize, lock, &bp, ops);
861 if (error)
862 return error;
863 if (bp)
864 xfs_buf_set_ref(bp, refval);
865 *bpp = bp;
866 return 0;
867}
868
869/*
870 * Read-ahead the block, don't wait for it, don't return a buffer.
871 * Long-form addressing.
872 */
873/* ARGSUSED */
874void
875xfs_btree_reada_bufl(
876 struct xfs_mount *mp, /* file system mount point */
877 xfs_fsblock_t fsbno, /* file system block number */
878 xfs_extlen_t count, /* count of filesystem blocks */
879 const struct xfs_buf_ops *ops)
880{
881 xfs_daddr_t d;
882
883 ASSERT(fsbno != NULLFSBLOCK);
884 d = XFS_FSB_TO_DADDR(mp, fsbno);
885 xfs_buf_readahead(mp->m_ddev_targp, d, mp->m_bsize * count, ops);
886}
887
888/*
889 * Read-ahead the block, don't wait for it, don't return a buffer.
890 * Short-form addressing.
891 */
892/* ARGSUSED */
893void
894xfs_btree_reada_bufs(
895 struct xfs_mount *mp, /* file system mount point */
896 xfs_agnumber_t agno, /* allocation group number */
897 xfs_agblock_t agbno, /* allocation group block number */
898 xfs_extlen_t count, /* count of filesystem blocks */
899 const struct xfs_buf_ops *ops)
900{
901 xfs_daddr_t d;
902
903 ASSERT(agno != NULLAGNUMBER);
904 ASSERT(agbno != NULLAGBLOCK);
905 d = XFS_AGB_TO_DADDR(mp, agno, agbno);
906 xfs_buf_readahead(mp->m_ddev_targp, d, mp->m_bsize * count, ops);
907}
908
909STATIC int
910xfs_btree_readahead_lblock(
911 struct xfs_btree_cur *cur,
912 int lr,
913 struct xfs_btree_block *block)
914{
915 int rval = 0;
916 xfs_fsblock_t left = be64_to_cpu(block->bb_u.l.bb_leftsib);
917 xfs_fsblock_t right = be64_to_cpu(block->bb_u.l.bb_rightsib);
918
919 if ((lr & XFS_BTCUR_LEFTRA) && left != NULLFSBLOCK) {
920 xfs_btree_reada_bufl(cur->bc_mp, left, 1,
921 cur->bc_ops->buf_ops);
922 rval++;
923 }
924
925 if ((lr & XFS_BTCUR_RIGHTRA) && right != NULLFSBLOCK) {
926 xfs_btree_reada_bufl(cur->bc_mp, right, 1,
927 cur->bc_ops->buf_ops);
928 rval++;
929 }
930
931 return rval;
932}
933
934STATIC int
935xfs_btree_readahead_sblock(
936 struct xfs_btree_cur *cur,
937 int lr,
938 struct xfs_btree_block *block)
939{
940 int rval = 0;
941 xfs_agblock_t left = be32_to_cpu(block->bb_u.s.bb_leftsib);
942 xfs_agblock_t right = be32_to_cpu(block->bb_u.s.bb_rightsib);
943
944
945 if ((lr & XFS_BTCUR_LEFTRA) && left != NULLAGBLOCK) {
946 xfs_btree_reada_bufs(cur->bc_mp, cur->bc_private.a.agno,
947 left, 1, cur->bc_ops->buf_ops);
948 rval++;
949 }
950
951 if ((lr & XFS_BTCUR_RIGHTRA) && right != NULLAGBLOCK) {
952 xfs_btree_reada_bufs(cur->bc_mp, cur->bc_private.a.agno,
953 right, 1, cur->bc_ops->buf_ops);
954 rval++;
955 }
956
957 return rval;
958}
959
960/*
961 * Read-ahead btree blocks, at the given level.
962 * Bits in lr are set from XFS_BTCUR_{LEFT,RIGHT}RA.
963 */
964STATIC int
965xfs_btree_readahead(
966 struct xfs_btree_cur *cur, /* btree cursor */
967 int lev, /* level in btree */
968 int lr) /* left/right bits */
969{
970 struct xfs_btree_block *block;
971
972 /*
973 * No readahead needed if we are at the root level and the
974 * btree root is stored in the inode.
975 */
976 if ((cur->bc_flags & XFS_BTREE_ROOT_IN_INODE) &&
977 (lev == cur->bc_nlevels - 1))
978 return 0;
979
980 if ((cur->bc_ra[lev] | lr) == cur->bc_ra[lev])
981 return 0;
982
983 cur->bc_ra[lev] |= lr;
984 block = XFS_BUF_TO_BLOCK(cur->bc_bufs[lev]);
985
986 if (cur->bc_flags & XFS_BTREE_LONG_PTRS)
987 return xfs_btree_readahead_lblock(cur, lr, block);
988 return xfs_btree_readahead_sblock(cur, lr, block);
989}
990
991STATIC xfs_daddr_t
992xfs_btree_ptr_to_daddr(
993 struct xfs_btree_cur *cur,
994 union xfs_btree_ptr *ptr)
995{
996 if (cur->bc_flags & XFS_BTREE_LONG_PTRS) {
997 ASSERT(ptr->l != cpu_to_be64(NULLFSBLOCK));
998
999 return XFS_FSB_TO_DADDR(cur->bc_mp, be64_to_cpu(ptr->l));
1000 } else {
1001 ASSERT(cur->bc_private.a.agno != NULLAGNUMBER);
1002 ASSERT(ptr->s != cpu_to_be32(NULLAGBLOCK));
1003
1004 return XFS_AGB_TO_DADDR(cur->bc_mp, cur->bc_private.a.agno,
1005 be32_to_cpu(ptr->s));
1006 }
1007}
1008
1009/*
1010 * Readahead @count btree blocks at the given @ptr location.
1011 *
1012 * We don't need to care about long or short form btrees here as we have a
1013 * method of converting the ptr directly to a daddr available to us.
1014 */
1015STATIC void
1016xfs_btree_readahead_ptr(
1017 struct xfs_btree_cur *cur,
1018 union xfs_btree_ptr *ptr,
1019 xfs_extlen_t count)
1020{
1021 xfs_buf_readahead(cur->bc_mp->m_ddev_targp,
1022 xfs_btree_ptr_to_daddr(cur, ptr),
1023 cur->bc_mp->m_bsize * count, cur->bc_ops->buf_ops);
1024}
1025
1026/*
1027 * Set the buffer for level "lev" in the cursor to bp, releasing
1028 * any previous buffer.
1029 */
1030STATIC void
1031xfs_btree_setbuf(
1032 xfs_btree_cur_t *cur, /* btree cursor */
1033 int lev, /* level in btree */
1034 xfs_buf_t *bp) /* new buffer to set */
1035{
1036 struct xfs_btree_block *b; /* btree block */
1037
1038 if (cur->bc_bufs[lev])
1039 xfs_trans_brelse(cur->bc_tp, cur->bc_bufs[lev]);
1040 cur->bc_bufs[lev] = bp;
1041 cur->bc_ra[lev] = 0;
1042
1043 b = XFS_BUF_TO_BLOCK(bp);
1044 if (cur->bc_flags & XFS_BTREE_LONG_PTRS) {
1045 if (b->bb_u.l.bb_leftsib == cpu_to_be64(NULLFSBLOCK))
1046 cur->bc_ra[lev] |= XFS_BTCUR_LEFTRA;
1047 if (b->bb_u.l.bb_rightsib == cpu_to_be64(NULLFSBLOCK))
1048 cur->bc_ra[lev] |= XFS_BTCUR_RIGHTRA;
1049 } else {
1050 if (b->bb_u.s.bb_leftsib == cpu_to_be32(NULLAGBLOCK))
1051 cur->bc_ra[lev] |= XFS_BTCUR_LEFTRA;
1052 if (b->bb_u.s.bb_rightsib == cpu_to_be32(NULLAGBLOCK))
1053 cur->bc_ra[lev] |= XFS_BTCUR_RIGHTRA;
1054 }
1055}
1056
1057bool
1058xfs_btree_ptr_is_null(
1059 struct xfs_btree_cur *cur,
1060 union xfs_btree_ptr *ptr)
1061{
1062 if (cur->bc_flags & XFS_BTREE_LONG_PTRS)
1063 return ptr->l == cpu_to_be64(NULLFSBLOCK);
1064 else
1065 return ptr->s == cpu_to_be32(NULLAGBLOCK);
1066}
1067
1068STATIC void
1069xfs_btree_set_ptr_null(
1070 struct xfs_btree_cur *cur,
1071 union xfs_btree_ptr *ptr)
1072{
1073 if (cur->bc_flags & XFS_BTREE_LONG_PTRS)
1074 ptr->l = cpu_to_be64(NULLFSBLOCK);
1075 else
1076 ptr->s = cpu_to_be32(NULLAGBLOCK);
1077}
1078
1079/*
1080 * Get/set/init sibling pointers
1081 */
1082void
1083xfs_btree_get_sibling(
1084 struct xfs_btree_cur *cur,
1085 struct xfs_btree_block *block,
1086 union xfs_btree_ptr *ptr,
1087 int lr)
1088{
1089 ASSERT(lr == XFS_BB_LEFTSIB || lr == XFS_BB_RIGHTSIB);
1090
1091 if (cur->bc_flags & XFS_BTREE_LONG_PTRS) {
1092 if (lr == XFS_BB_RIGHTSIB)
1093 ptr->l = block->bb_u.l.bb_rightsib;
1094 else
1095 ptr->l = block->bb_u.l.bb_leftsib;
1096 } else {
1097 if (lr == XFS_BB_RIGHTSIB)
1098 ptr->s = block->bb_u.s.bb_rightsib;
1099 else
1100 ptr->s = block->bb_u.s.bb_leftsib;
1101 }
1102}
1103
1104STATIC void
1105xfs_btree_set_sibling(
1106 struct xfs_btree_cur *cur,
1107 struct xfs_btree_block *block,
1108 union xfs_btree_ptr *ptr,
1109 int lr)
1110{
1111 ASSERT(lr == XFS_BB_LEFTSIB || lr == XFS_BB_RIGHTSIB);
1112
1113 if (cur->bc_flags & XFS_BTREE_LONG_PTRS) {
1114 if (lr == XFS_BB_RIGHTSIB)
1115 block->bb_u.l.bb_rightsib = ptr->l;
1116 else
1117 block->bb_u.l.bb_leftsib = ptr->l;
1118 } else {
1119 if (lr == XFS_BB_RIGHTSIB)
1120 block->bb_u.s.bb_rightsib = ptr->s;
1121 else
1122 block->bb_u.s.bb_leftsib = ptr->s;
1123 }
1124}
1125
1126void
1127xfs_btree_init_block_int(
1128 struct xfs_mount *mp,
1129 struct xfs_btree_block *buf,
1130 xfs_daddr_t blkno,
1131 xfs_btnum_t btnum,
1132 __u16 level,
1133 __u16 numrecs,
1134 __u64 owner,
1135 unsigned int flags)
1136{
1137 int crc = xfs_sb_version_hascrc(&mp->m_sb);
1138 __u32 magic = xfs_btree_magic(crc, btnum);
1139
1140 buf->bb_magic = cpu_to_be32(magic);
1141 buf->bb_level = cpu_to_be16(level);
1142 buf->bb_numrecs = cpu_to_be16(numrecs);
1143
1144 if (flags & XFS_BTREE_LONG_PTRS) {
1145 buf->bb_u.l.bb_leftsib = cpu_to_be64(NULLFSBLOCK);
1146 buf->bb_u.l.bb_rightsib = cpu_to_be64(NULLFSBLOCK);
1147 if (crc) {
1148 buf->bb_u.l.bb_blkno = cpu_to_be64(blkno);
1149 buf->bb_u.l.bb_owner = cpu_to_be64(owner);
1150 uuid_copy(&buf->bb_u.l.bb_uuid, &mp->m_sb.sb_meta_uuid);
1151 buf->bb_u.l.bb_pad = 0;
1152 buf->bb_u.l.bb_lsn = 0;
1153 }
1154 } else {
1155 /* owner is a 32 bit value on short blocks */
1156 __u32 __owner = (__u32)owner;
1157
1158 buf->bb_u.s.bb_leftsib = cpu_to_be32(NULLAGBLOCK);
1159 buf->bb_u.s.bb_rightsib = cpu_to_be32(NULLAGBLOCK);
1160 if (crc) {
1161 buf->bb_u.s.bb_blkno = cpu_to_be64(blkno);
1162 buf->bb_u.s.bb_owner = cpu_to_be32(__owner);
1163 uuid_copy(&buf->bb_u.s.bb_uuid, &mp->m_sb.sb_meta_uuid);
1164 buf->bb_u.s.bb_lsn = 0;
1165 }
1166 }
1167}
1168
1169void
1170xfs_btree_init_block(
1171 struct xfs_mount *mp,
1172 struct xfs_buf *bp,
1173 xfs_btnum_t btnum,
1174 __u16 level,
1175 __u16 numrecs,
1176 __u64 owner,
1177 unsigned int flags)
1178{
1179 xfs_btree_init_block_int(mp, XFS_BUF_TO_BLOCK(bp), bp->b_bn,
1180 btnum, level, numrecs, owner, flags);
1181}
1182
1183STATIC void
1184xfs_btree_init_block_cur(
1185 struct xfs_btree_cur *cur,
1186 struct xfs_buf *bp,
1187 int level,
1188 int numrecs)
1189{
1190 __u64 owner;
1191
1192 /*
1193 * we can pull the owner from the cursor right now as the different
1194 * owners align directly with the pointer size of the btree. This may
1195 * change in future, but is safe for current users of the generic btree
1196 * code.
1197 */
1198 if (cur->bc_flags & XFS_BTREE_LONG_PTRS)
1199 owner = cur->bc_private.b.ip->i_ino;
1200 else
1201 owner = cur->bc_private.a.agno;
1202
1203 xfs_btree_init_block_int(cur->bc_mp, XFS_BUF_TO_BLOCK(bp), bp->b_bn,
1204 cur->bc_btnum, level, numrecs,
1205 owner, cur->bc_flags);
1206}
1207
1208/*
1209 * Return true if ptr is the last record in the btree and
1210 * we need to track updates to this record. The decision
1211 * will be further refined in the update_lastrec method.
1212 */
1213STATIC int
1214xfs_btree_is_lastrec(
1215 struct xfs_btree_cur *cur,
1216 struct xfs_btree_block *block,
1217 int level)
1218{
1219 union xfs_btree_ptr ptr;
1220
1221 if (level > 0)
1222 return 0;
1223 if (!(cur->bc_flags & XFS_BTREE_LASTREC_UPDATE))
1224 return 0;
1225
1226 xfs_btree_get_sibling(cur, block, &ptr, XFS_BB_RIGHTSIB);
1227 if (!xfs_btree_ptr_is_null(cur, &ptr))
1228 return 0;
1229 return 1;
1230}
1231
1232STATIC void
1233xfs_btree_buf_to_ptr(
1234 struct xfs_btree_cur *cur,
1235 struct xfs_buf *bp,
1236 union xfs_btree_ptr *ptr)
1237{
1238 if (cur->bc_flags & XFS_BTREE_LONG_PTRS)
1239 ptr->l = cpu_to_be64(XFS_DADDR_TO_FSB(cur->bc_mp,
1240 XFS_BUF_ADDR(bp)));
1241 else {
1242 ptr->s = cpu_to_be32(xfs_daddr_to_agbno(cur->bc_mp,
1243 XFS_BUF_ADDR(bp)));
1244 }
1245}
1246
1247STATIC void
1248xfs_btree_set_refs(
1249 struct xfs_btree_cur *cur,
1250 struct xfs_buf *bp)
1251{
1252 switch (cur->bc_btnum) {
1253 case XFS_BTNUM_BNO:
1254 case XFS_BTNUM_CNT:
1255 xfs_buf_set_ref(bp, XFS_ALLOC_BTREE_REF);
1256 break;
1257 case XFS_BTNUM_INO:
1258 case XFS_BTNUM_FINO:
1259 xfs_buf_set_ref(bp, XFS_INO_BTREE_REF);
1260 break;
1261 case XFS_BTNUM_BMAP:
1262 xfs_buf_set_ref(bp, XFS_BMAP_BTREE_REF);
1263 break;
1264 case XFS_BTNUM_RMAP:
1265 xfs_buf_set_ref(bp, XFS_RMAP_BTREE_REF);
1266 break;
1267 case XFS_BTNUM_REFC:
1268 xfs_buf_set_ref(bp, XFS_REFC_BTREE_REF);
1269 break;
1270 default:
1271 ASSERT(0);
1272 }
1273}
1274
1275STATIC int
1276xfs_btree_get_buf_block(
1277 struct xfs_btree_cur *cur,
1278 union xfs_btree_ptr *ptr,
1279 int flags,
1280 struct xfs_btree_block **block,
1281 struct xfs_buf **bpp)
1282{
1283 struct xfs_mount *mp = cur->bc_mp;
1284 xfs_daddr_t d;
1285
1286 /* need to sort out how callers deal with failures first */
1287 ASSERT(!(flags & XBF_TRYLOCK));
1288
1289 d = xfs_btree_ptr_to_daddr(cur, ptr);
1290 *bpp = xfs_trans_get_buf(cur->bc_tp, mp->m_ddev_targp, d,
1291 mp->m_bsize, flags);
1292
1293 if (!*bpp)
1294 return -ENOMEM;
1295
1296 (*bpp)->b_ops = cur->bc_ops->buf_ops;
1297 *block = XFS_BUF_TO_BLOCK(*bpp);
1298 return 0;
1299}
1300
1301/*
1302 * Read in the buffer at the given ptr and return the buffer and
1303 * the block pointer within the buffer.
1304 */
1305STATIC int
1306xfs_btree_read_buf_block(
1307 struct xfs_btree_cur *cur,
1308 union xfs_btree_ptr *ptr,
1309 int flags,
1310 struct xfs_btree_block **block,
1311 struct xfs_buf **bpp)
1312{
1313 struct xfs_mount *mp = cur->bc_mp;
1314 xfs_daddr_t d;
1315 int error;
1316
1317 /* need to sort out how callers deal with failures first */
1318 ASSERT(!(flags & XBF_TRYLOCK));
1319
1320 d = xfs_btree_ptr_to_daddr(cur, ptr);
1321 error = xfs_trans_read_buf(mp, cur->bc_tp, mp->m_ddev_targp, d,
1322 mp->m_bsize, flags, bpp,
1323 cur->bc_ops->buf_ops);
1324 if (error)
1325 return error;
1326
1327 xfs_btree_set_refs(cur, *bpp);
1328 *block = XFS_BUF_TO_BLOCK(*bpp);
1329 return 0;
1330}
1331
1332/*
1333 * Copy keys from one btree block to another.
1334 */
1335STATIC void
1336xfs_btree_copy_keys(
1337 struct xfs_btree_cur *cur,
1338 union xfs_btree_key *dst_key,
1339 union xfs_btree_key *src_key,
1340 int numkeys)
1341{
1342 ASSERT(numkeys >= 0);
1343 memcpy(dst_key, src_key, numkeys * cur->bc_ops->key_len);
1344}
1345
1346/*
1347 * Copy records from one btree block to another.
1348 */
1349STATIC void
1350xfs_btree_copy_recs(
1351 struct xfs_btree_cur *cur,
1352 union xfs_btree_rec *dst_rec,
1353 union xfs_btree_rec *src_rec,
1354 int numrecs)
1355{
1356 ASSERT(numrecs >= 0);
1357 memcpy(dst_rec, src_rec, numrecs * cur->bc_ops->rec_len);
1358}
1359
1360/*
1361 * Copy block pointers from one btree block to another.
1362 */
1363STATIC void
1364xfs_btree_copy_ptrs(
1365 struct xfs_btree_cur *cur,
1366 union xfs_btree_ptr *dst_ptr,
1367 union xfs_btree_ptr *src_ptr,
1368 int numptrs)
1369{
1370 ASSERT(numptrs >= 0);
1371 memcpy(dst_ptr, src_ptr, numptrs * xfs_btree_ptr_len(cur));
1372}
1373
1374/*
1375 * Shift keys one index left/right inside a single btree block.
1376 */
1377STATIC void
1378xfs_btree_shift_keys(
1379 struct xfs_btree_cur *cur,
1380 union xfs_btree_key *key,
1381 int dir,
1382 int numkeys)
1383{
1384 char *dst_key;
1385
1386 ASSERT(numkeys >= 0);
1387 ASSERT(dir == 1 || dir == -1);
1388
1389 dst_key = (char *)key + (dir * cur->bc_ops->key_len);
1390 memmove(dst_key, key, numkeys * cur->bc_ops->key_len);
1391}
1392
1393/*
1394 * Shift records one index left/right inside a single btree block.
1395 */
1396STATIC void
1397xfs_btree_shift_recs(
1398 struct xfs_btree_cur *cur,
1399 union xfs_btree_rec *rec,
1400 int dir,
1401 int numrecs)
1402{
1403 char *dst_rec;
1404
1405 ASSERT(numrecs >= 0);
1406 ASSERT(dir == 1 || dir == -1);
1407
1408 dst_rec = (char *)rec + (dir * cur->bc_ops->rec_len);
1409 memmove(dst_rec, rec, numrecs * cur->bc_ops->rec_len);
1410}
1411
1412/*
1413 * Shift block pointers one index left/right inside a single btree block.
1414 */
1415STATIC void
1416xfs_btree_shift_ptrs(
1417 struct xfs_btree_cur *cur,
1418 union xfs_btree_ptr *ptr,
1419 int dir,
1420 int numptrs)
1421{
1422 char *dst_ptr;
1423
1424 ASSERT(numptrs >= 0);
1425 ASSERT(dir == 1 || dir == -1);
1426
1427 dst_ptr = (char *)ptr + (dir * xfs_btree_ptr_len(cur));
1428 memmove(dst_ptr, ptr, numptrs * xfs_btree_ptr_len(cur));
1429}
1430
1431/*
1432 * Log key values from the btree block.
1433 */
1434STATIC void
1435xfs_btree_log_keys(
1436 struct xfs_btree_cur *cur,
1437 struct xfs_buf *bp,
1438 int first,
1439 int last)
1440{
1441
1442 if (bp) {
1443 xfs_trans_buf_set_type(cur->bc_tp, bp, XFS_BLFT_BTREE_BUF);
1444 xfs_trans_log_buf(cur->bc_tp, bp,
1445 xfs_btree_key_offset(cur, first),
1446 xfs_btree_key_offset(cur, last + 1) - 1);
1447 } else {
1448 xfs_trans_log_inode(cur->bc_tp, cur->bc_private.b.ip,
1449 xfs_ilog_fbroot(cur->bc_private.b.whichfork));
1450 }
1451}
1452
1453/*
1454 * Log record values from the btree block.
1455 */
1456void
1457xfs_btree_log_recs(
1458 struct xfs_btree_cur *cur,
1459 struct xfs_buf *bp,
1460 int first,
1461 int last)
1462{
1463
1464 xfs_trans_buf_set_type(cur->bc_tp, bp, XFS_BLFT_BTREE_BUF);
1465 xfs_trans_log_buf(cur->bc_tp, bp,
1466 xfs_btree_rec_offset(cur, first),
1467 xfs_btree_rec_offset(cur, last + 1) - 1);
1468
1469}
1470
1471/*
1472 * Log block pointer fields from a btree block (nonleaf).
1473 */
1474STATIC void
1475xfs_btree_log_ptrs(
1476 struct xfs_btree_cur *cur, /* btree cursor */
1477 struct xfs_buf *bp, /* buffer containing btree block */
1478 int first, /* index of first pointer to log */
1479 int last) /* index of last pointer to log */
1480{
1481
1482 if (bp) {
1483 struct xfs_btree_block *block = XFS_BUF_TO_BLOCK(bp);
1484 int level = xfs_btree_get_level(block);
1485
1486 xfs_trans_buf_set_type(cur->bc_tp, bp, XFS_BLFT_BTREE_BUF);
1487 xfs_trans_log_buf(cur->bc_tp, bp,
1488 xfs_btree_ptr_offset(cur, first, level),
1489 xfs_btree_ptr_offset(cur, last + 1, level) - 1);
1490 } else {
1491 xfs_trans_log_inode(cur->bc_tp, cur->bc_private.b.ip,
1492 xfs_ilog_fbroot(cur->bc_private.b.whichfork));
1493 }
1494
1495}
1496
1497/*
1498 * Log fields from a btree block header.
1499 */
1500void
1501xfs_btree_log_block(
1502 struct xfs_btree_cur *cur, /* btree cursor */
1503 struct xfs_buf *bp, /* buffer containing btree block */
1504 int fields) /* mask of fields: XFS_BB_... */
1505{
1506 int first; /* first byte offset logged */
1507 int last; /* last byte offset logged */
1508 static const short soffsets[] = { /* table of offsets (short) */
1509 offsetof(struct xfs_btree_block, bb_magic),
1510 offsetof(struct xfs_btree_block, bb_level),
1511 offsetof(struct xfs_btree_block, bb_numrecs),
1512 offsetof(struct xfs_btree_block, bb_u.s.bb_leftsib),
1513 offsetof(struct xfs_btree_block, bb_u.s.bb_rightsib),
1514 offsetof(struct xfs_btree_block, bb_u.s.bb_blkno),
1515 offsetof(struct xfs_btree_block, bb_u.s.bb_lsn),
1516 offsetof(struct xfs_btree_block, bb_u.s.bb_uuid),
1517 offsetof(struct xfs_btree_block, bb_u.s.bb_owner),
1518 offsetof(struct xfs_btree_block, bb_u.s.bb_crc),
1519 XFS_BTREE_SBLOCK_CRC_LEN
1520 };
1521 static const short loffsets[] = { /* table of offsets (long) */
1522 offsetof(struct xfs_btree_block, bb_magic),
1523 offsetof(struct xfs_btree_block, bb_level),
1524 offsetof(struct xfs_btree_block, bb_numrecs),
1525 offsetof(struct xfs_btree_block, bb_u.l.bb_leftsib),
1526 offsetof(struct xfs_btree_block, bb_u.l.bb_rightsib),
1527 offsetof(struct xfs_btree_block, bb_u.l.bb_blkno),
1528 offsetof(struct xfs_btree_block, bb_u.l.bb_lsn),
1529 offsetof(struct xfs_btree_block, bb_u.l.bb_uuid),
1530 offsetof(struct xfs_btree_block, bb_u.l.bb_owner),
1531 offsetof(struct xfs_btree_block, bb_u.l.bb_crc),
1532 offsetof(struct xfs_btree_block, bb_u.l.bb_pad),
1533 XFS_BTREE_LBLOCK_CRC_LEN
1534 };
1535
1536 if (bp) {
1537 int nbits;
1538
1539 if (cur->bc_flags & XFS_BTREE_CRC_BLOCKS) {
1540 /*
1541 * We don't log the CRC when updating a btree
1542 * block but instead recreate it during log
1543 * recovery. As the log buffers have checksums
1544 * of their own this is safe and avoids logging a crc
1545 * update in a lot of places.
1546 */
1547 if (fields == XFS_BB_ALL_BITS)
1548 fields = XFS_BB_ALL_BITS_CRC;
1549 nbits = XFS_BB_NUM_BITS_CRC;
1550 } else {
1551 nbits = XFS_BB_NUM_BITS;
1552 }
1553 xfs_btree_offsets(fields,
1554 (cur->bc_flags & XFS_BTREE_LONG_PTRS) ?
1555 loffsets : soffsets,
1556 nbits, &first, &last);
1557 xfs_trans_buf_set_type(cur->bc_tp, bp, XFS_BLFT_BTREE_BUF);
1558 xfs_trans_log_buf(cur->bc_tp, bp, first, last);
1559 } else {
1560 xfs_trans_log_inode(cur->bc_tp, cur->bc_private.b.ip,
1561 xfs_ilog_fbroot(cur->bc_private.b.whichfork));
1562 }
1563}
1564
1565/*
1566 * Increment cursor by one record at the level.
1567 * For nonzero levels the leaf-ward information is untouched.
1568 */
1569int /* error */
1570xfs_btree_increment(
1571 struct xfs_btree_cur *cur,
1572 int level,
1573 int *stat) /* success/failure */
1574{
1575 struct xfs_btree_block *block;
1576 union xfs_btree_ptr ptr;
1577 struct xfs_buf *bp;
1578 int error; /* error return value */
1579 int lev;
1580
1581 ASSERT(level < cur->bc_nlevels);
1582
1583 /* Read-ahead to the right at this level. */
1584 xfs_btree_readahead(cur, level, XFS_BTCUR_RIGHTRA);
1585
1586 /* Get a pointer to the btree block. */
1587 block = xfs_btree_get_block(cur, level, &bp);
1588
1589#ifdef DEBUG
1590 error = xfs_btree_check_block(cur, block, level, bp);
1591 if (error)
1592 goto error0;
1593#endif
1594
1595 /* We're done if we remain in the block after the increment. */
1596 if (++cur->bc_ptrs[level] <= xfs_btree_get_numrecs(block))
1597 goto out1;
1598
1599 /* Fail if we just went off the right edge of the tree. */
1600 xfs_btree_get_sibling(cur, block, &ptr, XFS_BB_RIGHTSIB);
1601 if (xfs_btree_ptr_is_null(cur, &ptr))
1602 goto out0;
1603
1604 XFS_BTREE_STATS_INC(cur, increment);
1605
1606 /*
1607 * March up the tree incrementing pointers.
1608 * Stop when we don't go off the right edge of a block.
1609 */
1610 for (lev = level + 1; lev < cur->bc_nlevels; lev++) {
1611 block = xfs_btree_get_block(cur, lev, &bp);
1612
1613#ifdef DEBUG
1614 error = xfs_btree_check_block(cur, block, lev, bp);
1615 if (error)
1616 goto error0;
1617#endif
1618
1619 if (++cur->bc_ptrs[lev] <= xfs_btree_get_numrecs(block))
1620 break;
1621
1622 /* Read-ahead the right block for the next loop. */
1623 xfs_btree_readahead(cur, lev, XFS_BTCUR_RIGHTRA);
1624 }
1625
1626 /*
1627 * If we went off the root then we are either seriously
1628 * confused or have the tree root in an inode.
1629 */
1630 if (lev == cur->bc_nlevels) {
1631 if (cur->bc_flags & XFS_BTREE_ROOT_IN_INODE)
1632 goto out0;
1633 ASSERT(0);
1634 error = -EFSCORRUPTED;
1635 goto error0;
1636 }
1637 ASSERT(lev < cur->bc_nlevels);
1638
1639 /*
1640 * Now walk back down the tree, fixing up the cursor's buffer
1641 * pointers and key numbers.
1642 */
1643 for (block = xfs_btree_get_block(cur, lev, &bp); lev > level; ) {
1644 union xfs_btree_ptr *ptrp;
1645
1646 ptrp = xfs_btree_ptr_addr(cur, cur->bc_ptrs[lev], block);
1647 --lev;
1648 error = xfs_btree_read_buf_block(cur, ptrp, 0, &block, &bp);
1649 if (error)
1650 goto error0;
1651
1652 xfs_btree_setbuf(cur, lev, bp);
1653 cur->bc_ptrs[lev] = 1;
1654 }
1655out1:
1656 *stat = 1;
1657 return 0;
1658
1659out0:
1660 *stat = 0;
1661 return 0;
1662
1663error0:
1664 return error;
1665}
1666
1667/*
1668 * Decrement cursor by one record at the level.
1669 * For nonzero levels the leaf-ward information is untouched.
1670 */
1671int /* error */
1672xfs_btree_decrement(
1673 struct xfs_btree_cur *cur,
1674 int level,
1675 int *stat) /* success/failure */
1676{
1677 struct xfs_btree_block *block;
1678 xfs_buf_t *bp;
1679 int error; /* error return value */
1680 int lev;
1681 union xfs_btree_ptr ptr;
1682
1683 ASSERT(level < cur->bc_nlevels);
1684
1685 /* Read-ahead to the left at this level. */
1686 xfs_btree_readahead(cur, level, XFS_BTCUR_LEFTRA);
1687
1688 /* We're done if we remain in the block after the decrement. */
1689 if (--cur->bc_ptrs[level] > 0)
1690 goto out1;
1691
1692 /* Get a pointer to the btree block. */
1693 block = xfs_btree_get_block(cur, level, &bp);
1694
1695#ifdef DEBUG
1696 error = xfs_btree_check_block(cur, block, level, bp);
1697 if (error)
1698 goto error0;
1699#endif
1700
1701 /* Fail if we just went off the left edge of the tree. */
1702 xfs_btree_get_sibling(cur, block, &ptr, XFS_BB_LEFTSIB);
1703 if (xfs_btree_ptr_is_null(cur, &ptr))
1704 goto out0;
1705
1706 XFS_BTREE_STATS_INC(cur, decrement);
1707
1708 /*
1709 * March up the tree decrementing pointers.
1710 * Stop when we don't go off the left edge of a block.
1711 */
1712 for (lev = level + 1; lev < cur->bc_nlevels; lev++) {
1713 if (--cur->bc_ptrs[lev] > 0)
1714 break;
1715 /* Read-ahead the left block for the next loop. */
1716 xfs_btree_readahead(cur, lev, XFS_BTCUR_LEFTRA);
1717 }
1718
1719 /*
1720 * If we went off the root then we are seriously confused.
1721 * or the root of the tree is in an inode.
1722 */
1723 if (lev == cur->bc_nlevels) {
1724 if (cur->bc_flags & XFS_BTREE_ROOT_IN_INODE)
1725 goto out0;
1726 ASSERT(0);
1727 error = -EFSCORRUPTED;
1728 goto error0;
1729 }
1730 ASSERT(lev < cur->bc_nlevels);
1731
1732 /*
1733 * Now walk back down the tree, fixing up the cursor's buffer
1734 * pointers and key numbers.
1735 */
1736 for (block = xfs_btree_get_block(cur, lev, &bp); lev > level; ) {
1737 union xfs_btree_ptr *ptrp;
1738
1739 ptrp = xfs_btree_ptr_addr(cur, cur->bc_ptrs[lev], block);
1740 --lev;
1741 error = xfs_btree_read_buf_block(cur, ptrp, 0, &block, &bp);
1742 if (error)
1743 goto error0;
1744 xfs_btree_setbuf(cur, lev, bp);
1745 cur->bc_ptrs[lev] = xfs_btree_get_numrecs(block);
1746 }
1747out1:
1748 *stat = 1;
1749 return 0;
1750
1751out0:
1752 *stat = 0;
1753 return 0;
1754
1755error0:
1756 return error;
1757}
1758
1759int
1760xfs_btree_lookup_get_block(
1761 struct xfs_btree_cur *cur, /* btree cursor */
1762 int level, /* level in the btree */
1763 union xfs_btree_ptr *pp, /* ptr to btree block */
1764 struct xfs_btree_block **blkp) /* return btree block */
1765{
1766 struct xfs_buf *bp; /* buffer pointer for btree block */
1767 int error = 0;
1768
1769 /* special case the root block if in an inode */
1770 if ((cur->bc_flags & XFS_BTREE_ROOT_IN_INODE) &&
1771 (level == cur->bc_nlevels - 1)) {
1772 *blkp = xfs_btree_get_iroot(cur);
1773 return 0;
1774 }
1775
1776 /*
1777 * If the old buffer at this level for the disk address we are
1778 * looking for re-use it.
1779 *
1780 * Otherwise throw it away and get a new one.
1781 */
1782 bp = cur->bc_bufs[level];
1783 if (bp && XFS_BUF_ADDR(bp) == xfs_btree_ptr_to_daddr(cur, pp)) {
1784 *blkp = XFS_BUF_TO_BLOCK(bp);
1785 return 0;
1786 }
1787
1788 error = xfs_btree_read_buf_block(cur, pp, 0, blkp, &bp);
1789 if (error)
1790 return error;
1791
1792 /* Check the inode owner since the verifiers don't. */
1793 if (xfs_sb_version_hascrc(&cur->bc_mp->m_sb) &&
1794 !(cur->bc_private.b.flags & XFS_BTCUR_BPRV_INVALID_OWNER) &&
1795 (cur->bc_flags & XFS_BTREE_LONG_PTRS) &&
1796 be64_to_cpu((*blkp)->bb_u.l.bb_owner) !=
1797 cur->bc_private.b.ip->i_ino)
1798 goto out_bad;
1799
1800 /* Did we get the level we were looking for? */
1801 if (be16_to_cpu((*blkp)->bb_level) != level)
1802 goto out_bad;
1803
1804 /* Check that internal nodes have at least one record. */
1805 if (level != 0 && be16_to_cpu((*blkp)->bb_numrecs) == 0)
1806 goto out_bad;
1807
1808 xfs_btree_setbuf(cur, level, bp);
1809 return 0;
1810
1811out_bad:
1812 *blkp = NULL;
1813 xfs_trans_brelse(cur->bc_tp, bp);
1814 return -EFSCORRUPTED;
1815}
1816
1817/*
1818 * Get current search key. For level 0 we don't actually have a key
1819 * structure so we make one up from the record. For all other levels
1820 * we just return the right key.
1821 */
1822STATIC union xfs_btree_key *
1823xfs_lookup_get_search_key(
1824 struct xfs_btree_cur *cur,
1825 int level,
1826 int keyno,
1827 struct xfs_btree_block *block,
1828 union xfs_btree_key *kp)
1829{
1830 if (level == 0) {
1831 cur->bc_ops->init_key_from_rec(kp,
1832 xfs_btree_rec_addr(cur, keyno, block));
1833 return kp;
1834 }
1835
1836 return xfs_btree_key_addr(cur, keyno, block);
1837}
1838
1839/*
1840 * Lookup the record. The cursor is made to point to it, based on dir.
1841 * stat is set to 0 if can't find any such record, 1 for success.
1842 */
1843int /* error */
1844xfs_btree_lookup(
1845 struct xfs_btree_cur *cur, /* btree cursor */
1846 xfs_lookup_t dir, /* <=, ==, or >= */
1847 int *stat) /* success/failure */
1848{
1849 struct xfs_btree_block *block; /* current btree block */
1850 int64_t diff; /* difference for the current key */
1851 int error; /* error return value */
1852 int keyno; /* current key number */
1853 int level; /* level in the btree */
1854 union xfs_btree_ptr *pp; /* ptr to btree block */
1855 union xfs_btree_ptr ptr; /* ptr to btree block */
1856
1857 XFS_BTREE_STATS_INC(cur, lookup);
1858
1859 /* No such thing as a zero-level tree. */
1860 if (cur->bc_nlevels == 0)
1861 return -EFSCORRUPTED;
1862
1863 block = NULL;
1864 keyno = 0;
1865
1866 /* initialise start pointer from cursor */
1867 cur->bc_ops->init_ptr_from_cur(cur, &ptr);
1868 pp = &ptr;
1869
1870 /*
1871 * Iterate over each level in the btree, starting at the root.
1872 * For each level above the leaves, find the key we need, based
1873 * on the lookup record, then follow the corresponding block
1874 * pointer down to the next level.
1875 */
1876 for (level = cur->bc_nlevels - 1, diff = 1; level >= 0; level--) {
1877 /* Get the block we need to do the lookup on. */
1878 error = xfs_btree_lookup_get_block(cur, level, pp, &block);
1879 if (error)
1880 goto error0;
1881
1882 if (diff == 0) {
1883 /*
1884 * If we already had a key match at a higher level, we
1885 * know we need to use the first entry in this block.
1886 */
1887 keyno = 1;
1888 } else {
1889 /* Otherwise search this block. Do a binary search. */
1890
1891 int high; /* high entry number */
1892 int low; /* low entry number */
1893
1894 /* Set low and high entry numbers, 1-based. */
1895 low = 1;
1896 high = xfs_btree_get_numrecs(block);
1897 if (!high) {
1898 /* Block is empty, must be an empty leaf. */
1899 ASSERT(level == 0 && cur->bc_nlevels == 1);
1900
1901 cur->bc_ptrs[0] = dir != XFS_LOOKUP_LE;
1902 *stat = 0;
1903 return 0;
1904 }
1905
1906 /* Binary search the block. */
1907 while (low <= high) {
1908 union xfs_btree_key key;
1909 union xfs_btree_key *kp;
1910
1911 XFS_BTREE_STATS_INC(cur, compare);
1912
1913 /* keyno is average of low and high. */
1914 keyno = (low + high) >> 1;
1915
1916 /* Get current search key */
1917 kp = xfs_lookup_get_search_key(cur, level,
1918 keyno, block, &key);
1919
1920 /*
1921 * Compute difference to get next direction:
1922 * - less than, move right
1923 * - greater than, move left
1924 * - equal, we're done
1925 */
1926 diff = cur->bc_ops->key_diff(cur, kp);
1927 if (diff < 0)
1928 low = keyno + 1;
1929 else if (diff > 0)
1930 high = keyno - 1;
1931 else
1932 break;
1933 }
1934 }
1935
1936 /*
1937 * If there are more levels, set up for the next level
1938 * by getting the block number and filling in the cursor.
1939 */
1940 if (level > 0) {
1941 /*
1942 * If we moved left, need the previous key number,
1943 * unless there isn't one.
1944 */
1945 if (diff > 0 && --keyno < 1)
1946 keyno = 1;
1947 pp = xfs_btree_ptr_addr(cur, keyno, block);
1948
1949#ifdef DEBUG
1950 error = xfs_btree_check_ptr(cur, pp, 0, level);
1951 if (error)
1952 goto error0;
1953#endif
1954 cur->bc_ptrs[level] = keyno;
1955 }
1956 }
1957
1958 /* Done with the search. See if we need to adjust the results. */
1959 if (dir != XFS_LOOKUP_LE && diff < 0) {
1960 keyno++;
1961 /*
1962 * If ge search and we went off the end of the block, but it's
1963 * not the last block, we're in the wrong block.
1964 */
1965 xfs_btree_get_sibling(cur, block, &ptr, XFS_BB_RIGHTSIB);
1966 if (dir == XFS_LOOKUP_GE &&
1967 keyno > xfs_btree_get_numrecs(block) &&
1968 !xfs_btree_ptr_is_null(cur, &ptr)) {
1969 int i;
1970
1971 cur->bc_ptrs[0] = keyno;
1972 error = xfs_btree_increment(cur, 0, &i);
1973 if (error)
1974 goto error0;
1975 XFS_WANT_CORRUPTED_RETURN(cur->bc_mp, i == 1);
1976 *stat = 1;
1977 return 0;
1978 }
1979 } else if (dir == XFS_LOOKUP_LE && diff > 0)
1980 keyno--;
1981 cur->bc_ptrs[0] = keyno;
1982
1983 /* Return if we succeeded or not. */
1984 if (keyno == 0 || keyno > xfs_btree_get_numrecs(block))
1985 *stat = 0;
1986 else if (dir != XFS_LOOKUP_EQ || diff == 0)
1987 *stat = 1;
1988 else
1989 *stat = 0;
1990 return 0;
1991
1992error0:
1993 return error;
1994}
1995
1996/* Find the high key storage area from a regular key. */
1997union xfs_btree_key *
1998xfs_btree_high_key_from_key(
1999 struct xfs_btree_cur *cur,
2000 union xfs_btree_key *key)
2001{
2002 ASSERT(cur->bc_flags & XFS_BTREE_OVERLAPPING);
2003 return (union xfs_btree_key *)((char *)key +
2004 (cur->bc_ops->key_len / 2));
2005}
2006
2007/* Determine the low (and high if overlapped) keys of a leaf block */
2008STATIC void
2009xfs_btree_get_leaf_keys(
2010 struct xfs_btree_cur *cur,
2011 struct xfs_btree_block *block,
2012 union xfs_btree_key *key)
2013{
2014 union xfs_btree_key max_hkey;
2015 union xfs_btree_key hkey;
2016 union xfs_btree_rec *rec;
2017 union xfs_btree_key *high;
2018 int n;
2019
2020 rec = xfs_btree_rec_addr(cur, 1, block);
2021 cur->bc_ops->init_key_from_rec(key, rec);
2022
2023 if (cur->bc_flags & XFS_BTREE_OVERLAPPING) {
2024
2025 cur->bc_ops->init_high_key_from_rec(&max_hkey, rec);
2026 for (n = 2; n <= xfs_btree_get_numrecs(block); n++) {
2027 rec = xfs_btree_rec_addr(cur, n, block);
2028 cur->bc_ops->init_high_key_from_rec(&hkey, rec);
2029 if (cur->bc_ops->diff_two_keys(cur, &hkey, &max_hkey)
2030 > 0)
2031 max_hkey = hkey;
2032 }
2033
2034 high = xfs_btree_high_key_from_key(cur, key);
2035 memcpy(high, &max_hkey, cur->bc_ops->key_len / 2);
2036 }
2037}
2038
2039/* Determine the low (and high if overlapped) keys of a node block */
2040STATIC void
2041xfs_btree_get_node_keys(
2042 struct xfs_btree_cur *cur,
2043 struct xfs_btree_block *block,
2044 union xfs_btree_key *key)
2045{
2046 union xfs_btree_key *hkey;
2047 union xfs_btree_key *max_hkey;
2048 union xfs_btree_key *high;
2049 int n;
2050
2051 if (cur->bc_flags & XFS_BTREE_OVERLAPPING) {
2052 memcpy(key, xfs_btree_key_addr(cur, 1, block),
2053 cur->bc_ops->key_len / 2);
2054
2055 max_hkey = xfs_btree_high_key_addr(cur, 1, block);
2056 for (n = 2; n <= xfs_btree_get_numrecs(block); n++) {
2057 hkey = xfs_btree_high_key_addr(cur, n, block);
2058 if (cur->bc_ops->diff_two_keys(cur, hkey, max_hkey) > 0)
2059 max_hkey = hkey;
2060 }
2061
2062 high = xfs_btree_high_key_from_key(cur, key);
2063 memcpy(high, max_hkey, cur->bc_ops->key_len / 2);
2064 } else {
2065 memcpy(key, xfs_btree_key_addr(cur, 1, block),
2066 cur->bc_ops->key_len);
2067 }
2068}
2069
2070/* Derive the keys for any btree block. */
2071void
2072xfs_btree_get_keys(
2073 struct xfs_btree_cur *cur,
2074 struct xfs_btree_block *block,
2075 union xfs_btree_key *key)
2076{
2077 if (be16_to_cpu(block->bb_level) == 0)
2078 xfs_btree_get_leaf_keys(cur, block, key);
2079 else
2080 xfs_btree_get_node_keys(cur, block, key);
2081}
2082
2083/*
2084 * Decide if we need to update the parent keys of a btree block. For
2085 * a standard btree this is only necessary if we're updating the first
2086 * record/key. For an overlapping btree, we must always update the
2087 * keys because the highest key can be in any of the records or keys
2088 * in the block.
2089 */
2090static inline bool
2091xfs_btree_needs_key_update(
2092 struct xfs_btree_cur *cur,
2093 int ptr)
2094{
2095 return (cur->bc_flags & XFS_BTREE_OVERLAPPING) || ptr == 1;
2096}
2097
2098/*
2099 * Update the low and high parent keys of the given level, progressing
2100 * towards the root. If force_all is false, stop if the keys for a given
2101 * level do not need updating.
2102 */
2103STATIC int
2104__xfs_btree_updkeys(
2105 struct xfs_btree_cur *cur,
2106 int level,
2107 struct xfs_btree_block *block,
2108 struct xfs_buf *bp0,
2109 bool force_all)
2110{
2111 union xfs_btree_key key; /* keys from current level */
2112 union xfs_btree_key *lkey; /* keys from the next level up */
2113 union xfs_btree_key *hkey;
2114 union xfs_btree_key *nlkey; /* keys from the next level up */
2115 union xfs_btree_key *nhkey;
2116 struct xfs_buf *bp;
2117 int ptr;
2118
2119 ASSERT(cur->bc_flags & XFS_BTREE_OVERLAPPING);
2120
2121 /* Exit if there aren't any parent levels to update. */
2122 if (level + 1 >= cur->bc_nlevels)
2123 return 0;
2124
2125 trace_xfs_btree_updkeys(cur, level, bp0);
2126
2127 lkey = &key;
2128 hkey = xfs_btree_high_key_from_key(cur, lkey);
2129 xfs_btree_get_keys(cur, block, lkey);
2130 for (level++; level < cur->bc_nlevels; level++) {
2131#ifdef DEBUG
2132 int error;
2133#endif
2134 block = xfs_btree_get_block(cur, level, &bp);
2135 trace_xfs_btree_updkeys(cur, level, bp);
2136#ifdef DEBUG
2137 error = xfs_btree_check_block(cur, block, level, bp);
2138 if (error)
2139 return error;
2140#endif
2141 ptr = cur->bc_ptrs[level];
2142 nlkey = xfs_btree_key_addr(cur, ptr, block);
2143 nhkey = xfs_btree_high_key_addr(cur, ptr, block);
2144 if (!force_all &&
2145 !(cur->bc_ops->diff_two_keys(cur, nlkey, lkey) != 0 ||
2146 cur->bc_ops->diff_two_keys(cur, nhkey, hkey) != 0))
2147 break;
2148 xfs_btree_copy_keys(cur, nlkey, lkey, 1);
2149 xfs_btree_log_keys(cur, bp, ptr, ptr);
2150 if (level + 1 >= cur->bc_nlevels)
2151 break;
2152 xfs_btree_get_node_keys(cur, block, lkey);
2153 }
2154
2155 return 0;
2156}
2157
2158/* Update all the keys from some level in cursor back to the root. */
2159STATIC int
2160xfs_btree_updkeys_force(
2161 struct xfs_btree_cur *cur,
2162 int level)
2163{
2164 struct xfs_buf *bp;
2165 struct xfs_btree_block *block;
2166
2167 block = xfs_btree_get_block(cur, level, &bp);
2168 return __xfs_btree_updkeys(cur, level, block, bp, true);
2169}
2170
2171/*
2172 * Update the parent keys of the given level, progressing towards the root.
2173 */
2174STATIC int
2175xfs_btree_update_keys(
2176 struct xfs_btree_cur *cur,
2177 int level)
2178{
2179 struct xfs_btree_block *block;
2180 struct xfs_buf *bp;
2181 union xfs_btree_key *kp;
2182 union xfs_btree_key key;
2183 int ptr;
2184
2185 ASSERT(level >= 0);
2186
2187 block = xfs_btree_get_block(cur, level, &bp);
2188 if (cur->bc_flags & XFS_BTREE_OVERLAPPING)
2189 return __xfs_btree_updkeys(cur, level, block, bp, false);
2190
2191 /*
2192 * Go up the tree from this level toward the root.
2193 * At each level, update the key value to the value input.
2194 * Stop when we reach a level where the cursor isn't pointing
2195 * at the first entry in the block.
2196 */
2197 xfs_btree_get_keys(cur, block, &key);
2198 for (level++, ptr = 1; ptr == 1 && level < cur->bc_nlevels; level++) {
2199#ifdef DEBUG
2200 int error;
2201#endif
2202 block = xfs_btree_get_block(cur, level, &bp);
2203#ifdef DEBUG
2204 error = xfs_btree_check_block(cur, block, level, bp);
2205 if (error)
2206 return error;
2207#endif
2208 ptr = cur->bc_ptrs[level];
2209 kp = xfs_btree_key_addr(cur, ptr, block);
2210 xfs_btree_copy_keys(cur, kp, &key, 1);
2211 xfs_btree_log_keys(cur, bp, ptr, ptr);
2212 }
2213
2214 return 0;
2215}
2216
2217/*
2218 * Update the record referred to by cur to the value in the
2219 * given record. This either works (return 0) or gets an
2220 * EFSCORRUPTED error.
2221 */
2222int
2223xfs_btree_update(
2224 struct xfs_btree_cur *cur,
2225 union xfs_btree_rec *rec)
2226{
2227 struct xfs_btree_block *block;
2228 struct xfs_buf *bp;
2229 int error;
2230 int ptr;
2231 union xfs_btree_rec *rp;
2232
2233 /* Pick up the current block. */
2234 block = xfs_btree_get_block(cur, 0, &bp);
2235
2236#ifdef DEBUG
2237 error = xfs_btree_check_block(cur, block, 0, bp);
2238 if (error)
2239 goto error0;
2240#endif
2241 /* Get the address of the rec to be updated. */
2242 ptr = cur->bc_ptrs[0];
2243 rp = xfs_btree_rec_addr(cur, ptr, block);
2244
2245 /* Fill in the new contents and log them. */
2246 xfs_btree_copy_recs(cur, rp, rec, 1);
2247 xfs_btree_log_recs(cur, bp, ptr, ptr);
2248
2249 /*
2250 * If we are tracking the last record in the tree and
2251 * we are at the far right edge of the tree, update it.
2252 */
2253 if (xfs_btree_is_lastrec(cur, block, 0)) {
2254 cur->bc_ops->update_lastrec(cur, block, rec,
2255 ptr, LASTREC_UPDATE);
2256 }
2257
2258 /* Pass new key value up to our parent. */
2259 if (xfs_btree_needs_key_update(cur, ptr)) {
2260 error = xfs_btree_update_keys(cur, 0);
2261 if (error)
2262 goto error0;
2263 }
2264
2265 return 0;
2266
2267error0:
2268 return error;
2269}
2270
2271/*
2272 * Move 1 record left from cur/level if possible.
2273 * Update cur to reflect the new path.
2274 */
2275STATIC int /* error */
2276xfs_btree_lshift(
2277 struct xfs_btree_cur *cur,
2278 int level,
2279 int *stat) /* success/failure */
2280{
2281 struct xfs_buf *lbp; /* left buffer pointer */
2282 struct xfs_btree_block *left; /* left btree block */
2283 int lrecs; /* left record count */
2284 struct xfs_buf *rbp; /* right buffer pointer */
2285 struct xfs_btree_block *right; /* right btree block */
2286 struct xfs_btree_cur *tcur; /* temporary btree cursor */
2287 int rrecs; /* right record count */
2288 union xfs_btree_ptr lptr; /* left btree pointer */
2289 union xfs_btree_key *rkp = NULL; /* right btree key */
2290 union xfs_btree_ptr *rpp = NULL; /* right address pointer */
2291 union xfs_btree_rec *rrp = NULL; /* right record pointer */
2292 int error; /* error return value */
2293 int i;
2294
2295 if ((cur->bc_flags & XFS_BTREE_ROOT_IN_INODE) &&
2296 level == cur->bc_nlevels - 1)
2297 goto out0;
2298
2299 /* Set up variables for this block as "right". */
2300 right = xfs_btree_get_block(cur, level, &rbp);
2301
2302#ifdef DEBUG
2303 error = xfs_btree_check_block(cur, right, level, rbp);
2304 if (error)
2305 goto error0;
2306#endif
2307
2308 /* If we've got no left sibling then we can't shift an entry left. */
2309 xfs_btree_get_sibling(cur, right, &lptr, XFS_BB_LEFTSIB);
2310 if (xfs_btree_ptr_is_null(cur, &lptr))
2311 goto out0;
2312
2313 /*
2314 * If the cursor entry is the one that would be moved, don't
2315 * do it... it's too complicated.
2316 */
2317 if (cur->bc_ptrs[level] <= 1)
2318 goto out0;
2319
2320 /* Set up the left neighbor as "left". */
2321 error = xfs_btree_read_buf_block(cur, &lptr, 0, &left, &lbp);
2322 if (error)
2323 goto error0;
2324
2325 /* If it's full, it can't take another entry. */
2326 lrecs = xfs_btree_get_numrecs(left);
2327 if (lrecs == cur->bc_ops->get_maxrecs(cur, level))
2328 goto out0;
2329
2330 rrecs = xfs_btree_get_numrecs(right);
2331
2332 /*
2333 * We add one entry to the left side and remove one for the right side.
2334 * Account for it here, the changes will be updated on disk and logged
2335 * later.
2336 */
2337 lrecs++;
2338 rrecs--;
2339
2340 XFS_BTREE_STATS_INC(cur, lshift);
2341 XFS_BTREE_STATS_ADD(cur, moves, 1);
2342
2343 /*
2344 * If non-leaf, copy a key and a ptr to the left block.
2345 * Log the changes to the left block.
2346 */
2347 if (level > 0) {
2348 /* It's a non-leaf. Move keys and pointers. */
2349 union xfs_btree_key *lkp; /* left btree key */
2350 union xfs_btree_ptr *lpp; /* left address pointer */
2351
2352 lkp = xfs_btree_key_addr(cur, lrecs, left);
2353 rkp = xfs_btree_key_addr(cur, 1, right);
2354
2355 lpp = xfs_btree_ptr_addr(cur, lrecs, left);
2356 rpp = xfs_btree_ptr_addr(cur, 1, right);
2357#ifdef DEBUG
2358 error = xfs_btree_check_ptr(cur, rpp, 0, level);
2359 if (error)
2360 goto error0;
2361#endif
2362 xfs_btree_copy_keys(cur, lkp, rkp, 1);
2363 xfs_btree_copy_ptrs(cur, lpp, rpp, 1);
2364
2365 xfs_btree_log_keys(cur, lbp, lrecs, lrecs);
2366 xfs_btree_log_ptrs(cur, lbp, lrecs, lrecs);
2367
2368 ASSERT(cur->bc_ops->keys_inorder(cur,
2369 xfs_btree_key_addr(cur, lrecs - 1, left), lkp));
2370 } else {
2371 /* It's a leaf. Move records. */
2372 union xfs_btree_rec *lrp; /* left record pointer */
2373
2374 lrp = xfs_btree_rec_addr(cur, lrecs, left);
2375 rrp = xfs_btree_rec_addr(cur, 1, right);
2376
2377 xfs_btree_copy_recs(cur, lrp, rrp, 1);
2378 xfs_btree_log_recs(cur, lbp, lrecs, lrecs);
2379
2380 ASSERT(cur->bc_ops->recs_inorder(cur,
2381 xfs_btree_rec_addr(cur, lrecs - 1, left), lrp));
2382 }
2383
2384 xfs_btree_set_numrecs(left, lrecs);
2385 xfs_btree_log_block(cur, lbp, XFS_BB_NUMRECS);
2386
2387 xfs_btree_set_numrecs(right, rrecs);
2388 xfs_btree_log_block(cur, rbp, XFS_BB_NUMRECS);
2389
2390 /*
2391 * Slide the contents of right down one entry.
2392 */
2393 XFS_BTREE_STATS_ADD(cur, moves, rrecs - 1);
2394 if (level > 0) {
2395 /* It's a nonleaf. operate on keys and ptrs */
2396#ifdef DEBUG
2397 int i; /* loop index */
2398
2399 for (i = 0; i < rrecs; i++) {
2400 error = xfs_btree_check_ptr(cur, rpp, i + 1, level);
2401 if (error)
2402 goto error0;
2403 }
2404#endif
2405 xfs_btree_shift_keys(cur,
2406 xfs_btree_key_addr(cur, 2, right),
2407 -1, rrecs);
2408 xfs_btree_shift_ptrs(cur,
2409 xfs_btree_ptr_addr(cur, 2, right),
2410 -1, rrecs);
2411
2412 xfs_btree_log_keys(cur, rbp, 1, rrecs);
2413 xfs_btree_log_ptrs(cur, rbp, 1, rrecs);
2414 } else {
2415 /* It's a leaf. operate on records */
2416 xfs_btree_shift_recs(cur,
2417 xfs_btree_rec_addr(cur, 2, right),
2418 -1, rrecs);
2419 xfs_btree_log_recs(cur, rbp, 1, rrecs);
2420 }
2421
2422 /*
2423 * Using a temporary cursor, update the parent key values of the
2424 * block on the left.
2425 */
2426 if (cur->bc_flags & XFS_BTREE_OVERLAPPING) {
2427 error = xfs_btree_dup_cursor(cur, &tcur);
2428 if (error)
2429 goto error0;
2430 i = xfs_btree_firstrec(tcur, level);
2431 XFS_WANT_CORRUPTED_GOTO(tcur->bc_mp, i == 1, error0);
2432
2433 error = xfs_btree_decrement(tcur, level, &i);
2434 if (error)
2435 goto error1;
2436
2437 /* Update the parent high keys of the left block, if needed. */
2438 error = xfs_btree_update_keys(tcur, level);
2439 if (error)
2440 goto error1;
2441
2442 xfs_btree_del_cursor(tcur, XFS_BTREE_NOERROR);
2443 }
2444
2445 /* Update the parent keys of the right block. */
2446 error = xfs_btree_update_keys(cur, level);
2447 if (error)
2448 goto error0;
2449
2450 /* Slide the cursor value left one. */
2451 cur->bc_ptrs[level]--;
2452
2453 *stat = 1;
2454 return 0;
2455
2456out0:
2457 *stat = 0;
2458 return 0;
2459
2460error0:
2461 return error;
2462
2463error1:
2464 xfs_btree_del_cursor(tcur, XFS_BTREE_ERROR);
2465 return error;
2466}
2467
2468/*
2469 * Move 1 record right from cur/level if possible.
2470 * Update cur to reflect the new path.
2471 */
2472STATIC int /* error */
2473xfs_btree_rshift(
2474 struct xfs_btree_cur *cur,
2475 int level,
2476 int *stat) /* success/failure */
2477{
2478 struct xfs_buf *lbp; /* left buffer pointer */
2479 struct xfs_btree_block *left; /* left btree block */
2480 struct xfs_buf *rbp; /* right buffer pointer */
2481 struct xfs_btree_block *right; /* right btree block */
2482 struct xfs_btree_cur *tcur; /* temporary btree cursor */
2483 union xfs_btree_ptr rptr; /* right block pointer */
2484 union xfs_btree_key *rkp; /* right btree key */
2485 int rrecs; /* right record count */
2486 int lrecs; /* left record count */
2487 int error; /* error return value */
2488 int i; /* loop counter */
2489
2490 if ((cur->bc_flags & XFS_BTREE_ROOT_IN_INODE) &&
2491 (level == cur->bc_nlevels - 1))
2492 goto out0;
2493
2494 /* Set up variables for this block as "left". */
2495 left = xfs_btree_get_block(cur, level, &lbp);
2496
2497#ifdef DEBUG
2498 error = xfs_btree_check_block(cur, left, level, lbp);
2499 if (error)
2500 goto error0;
2501#endif
2502
2503 /* If we've got no right sibling then we can't shift an entry right. */
2504 xfs_btree_get_sibling(cur, left, &rptr, XFS_BB_RIGHTSIB);
2505 if (xfs_btree_ptr_is_null(cur, &rptr))
2506 goto out0;
2507
2508 /*
2509 * If the cursor entry is the one that would be moved, don't
2510 * do it... it's too complicated.
2511 */
2512 lrecs = xfs_btree_get_numrecs(left);
2513 if (cur->bc_ptrs[level] >= lrecs)
2514 goto out0;
2515
2516 /* Set up the right neighbor as "right". */
2517 error = xfs_btree_read_buf_block(cur, &rptr, 0, &right, &rbp);
2518 if (error)
2519 goto error0;
2520
2521 /* If it's full, it can't take another entry. */
2522 rrecs = xfs_btree_get_numrecs(right);
2523 if (rrecs == cur->bc_ops->get_maxrecs(cur, level))
2524 goto out0;
2525
2526 XFS_BTREE_STATS_INC(cur, rshift);
2527 XFS_BTREE_STATS_ADD(cur, moves, rrecs);
2528
2529 /*
2530 * Make a hole at the start of the right neighbor block, then
2531 * copy the last left block entry to the hole.
2532 */
2533 if (level > 0) {
2534 /* It's a nonleaf. make a hole in the keys and ptrs */
2535 union xfs_btree_key *lkp;
2536 union xfs_btree_ptr *lpp;
2537 union xfs_btree_ptr *rpp;
2538
2539 lkp = xfs_btree_key_addr(cur, lrecs, left);
2540 lpp = xfs_btree_ptr_addr(cur, lrecs, left);
2541 rkp = xfs_btree_key_addr(cur, 1, right);
2542 rpp = xfs_btree_ptr_addr(cur, 1, right);
2543
2544#ifdef DEBUG
2545 for (i = rrecs - 1; i >= 0; i--) {
2546 error = xfs_btree_check_ptr(cur, rpp, i, level);
2547 if (error)
2548 goto error0;
2549 }
2550#endif
2551
2552 xfs_btree_shift_keys(cur, rkp, 1, rrecs);
2553 xfs_btree_shift_ptrs(cur, rpp, 1, rrecs);
2554
2555#ifdef DEBUG
2556 error = xfs_btree_check_ptr(cur, lpp, 0, level);
2557 if (error)
2558 goto error0;
2559#endif
2560
2561 /* Now put the new data in, and log it. */
2562 xfs_btree_copy_keys(cur, rkp, lkp, 1);
2563 xfs_btree_copy_ptrs(cur, rpp, lpp, 1);
2564
2565 xfs_btree_log_keys(cur, rbp, 1, rrecs + 1);
2566 xfs_btree_log_ptrs(cur, rbp, 1, rrecs + 1);
2567
2568 ASSERT(cur->bc_ops->keys_inorder(cur, rkp,
2569 xfs_btree_key_addr(cur, 2, right)));
2570 } else {
2571 /* It's a leaf. make a hole in the records */
2572 union xfs_btree_rec *lrp;
2573 union xfs_btree_rec *rrp;
2574
2575 lrp = xfs_btree_rec_addr(cur, lrecs, left);
2576 rrp = xfs_btree_rec_addr(cur, 1, right);
2577
2578 xfs_btree_shift_recs(cur, rrp, 1, rrecs);
2579
2580 /* Now put the new data in, and log it. */
2581 xfs_btree_copy_recs(cur, rrp, lrp, 1);
2582 xfs_btree_log_recs(cur, rbp, 1, rrecs + 1);
2583 }
2584
2585 /*
2586 * Decrement and log left's numrecs, bump and log right's numrecs.
2587 */
2588 xfs_btree_set_numrecs(left, --lrecs);
2589 xfs_btree_log_block(cur, lbp, XFS_BB_NUMRECS);
2590
2591 xfs_btree_set_numrecs(right, ++rrecs);
2592 xfs_btree_log_block(cur, rbp, XFS_BB_NUMRECS);
2593
2594 /*
2595 * Using a temporary cursor, update the parent key values of the
2596 * block on the right.
2597 */
2598 error = xfs_btree_dup_cursor(cur, &tcur);
2599 if (error)
2600 goto error0;
2601 i = xfs_btree_lastrec(tcur, level);
2602 XFS_WANT_CORRUPTED_GOTO(tcur->bc_mp, i == 1, error0);
2603
2604 error = xfs_btree_increment(tcur, level, &i);
2605 if (error)
2606 goto error1;
2607
2608 /* Update the parent high keys of the left block, if needed. */
2609 if (cur->bc_flags & XFS_BTREE_OVERLAPPING) {
2610 error = xfs_btree_update_keys(cur, level);
2611 if (error)
2612 goto error1;
2613 }
2614
2615 /* Update the parent keys of the right block. */
2616 error = xfs_btree_update_keys(tcur, level);
2617 if (error)
2618 goto error1;
2619
2620 xfs_btree_del_cursor(tcur, XFS_BTREE_NOERROR);
2621
2622 *stat = 1;
2623 return 0;
2624
2625out0:
2626 *stat = 0;
2627 return 0;
2628
2629error0:
2630 return error;
2631
2632error1:
2633 xfs_btree_del_cursor(tcur, XFS_BTREE_ERROR);
2634 return error;
2635}
2636
2637/*
2638 * Split cur/level block in half.
2639 * Return new block number and the key to its first
2640 * record (to be inserted into parent).
2641 */
2642STATIC int /* error */
2643__xfs_btree_split(
2644 struct xfs_btree_cur *cur,
2645 int level,
2646 union xfs_btree_ptr *ptrp,
2647 union xfs_btree_key *key,
2648 struct xfs_btree_cur **curp,
2649 int *stat) /* success/failure */
2650{
2651 union xfs_btree_ptr lptr; /* left sibling block ptr */
2652 struct xfs_buf *lbp; /* left buffer pointer */
2653 struct xfs_btree_block *left; /* left btree block */
2654 union xfs_btree_ptr rptr; /* right sibling block ptr */
2655 struct xfs_buf *rbp; /* right buffer pointer */
2656 struct xfs_btree_block *right; /* right btree block */
2657 union xfs_btree_ptr rrptr; /* right-right sibling ptr */
2658 struct xfs_buf *rrbp; /* right-right buffer pointer */
2659 struct xfs_btree_block *rrblock; /* right-right btree block */
2660 int lrecs;
2661 int rrecs;
2662 int src_index;
2663 int error; /* error return value */
2664#ifdef DEBUG
2665 int i;
2666#endif
2667
2668 XFS_BTREE_STATS_INC(cur, split);
2669
2670 /* Set up left block (current one). */
2671 left = xfs_btree_get_block(cur, level, &lbp);
2672
2673#ifdef DEBUG
2674 error = xfs_btree_check_block(cur, left, level, lbp);
2675 if (error)
2676 goto error0;
2677#endif
2678
2679 xfs_btree_buf_to_ptr(cur, lbp, &lptr);
2680
2681 /* Allocate the new block. If we can't do it, we're toast. Give up. */
2682 error = cur->bc_ops->alloc_block(cur, &lptr, &rptr, stat);
2683 if (error)
2684 goto error0;
2685 if (*stat == 0)
2686 goto out0;
2687 XFS_BTREE_STATS_INC(cur, alloc);
2688
2689 /* Set up the new block as "right". */
2690 error = xfs_btree_get_buf_block(cur, &rptr, 0, &right, &rbp);
2691 if (error)
2692 goto error0;
2693
2694 /* Fill in the btree header for the new right block. */
2695 xfs_btree_init_block_cur(cur, rbp, xfs_btree_get_level(left), 0);
2696
2697 /*
2698 * Split the entries between the old and the new block evenly.
2699 * Make sure that if there's an odd number of entries now, that
2700 * each new block will have the same number of entries.
2701 */
2702 lrecs = xfs_btree_get_numrecs(left);
2703 rrecs = lrecs / 2;
2704 if ((lrecs & 1) && cur->bc_ptrs[level] <= rrecs + 1)
2705 rrecs++;
2706 src_index = (lrecs - rrecs + 1);
2707
2708 XFS_BTREE_STATS_ADD(cur, moves, rrecs);
2709
2710 /* Adjust numrecs for the later get_*_keys() calls. */
2711 lrecs -= rrecs;
2712 xfs_btree_set_numrecs(left, lrecs);
2713 xfs_btree_set_numrecs(right, xfs_btree_get_numrecs(right) + rrecs);
2714
2715 /*
2716 * Copy btree block entries from the left block over to the
2717 * new block, the right. Update the right block and log the
2718 * changes.
2719 */
2720 if (level > 0) {
2721 /* It's a non-leaf. Move keys and pointers. */
2722 union xfs_btree_key *lkp; /* left btree key */
2723 union xfs_btree_ptr *lpp; /* left address pointer */
2724 union xfs_btree_key *rkp; /* right btree key */
2725 union xfs_btree_ptr *rpp; /* right address pointer */
2726
2727 lkp = xfs_btree_key_addr(cur, src_index, left);
2728 lpp = xfs_btree_ptr_addr(cur, src_index, left);
2729 rkp = xfs_btree_key_addr(cur, 1, right);
2730 rpp = xfs_btree_ptr_addr(cur, 1, right);
2731
2732#ifdef DEBUG
2733 for (i = src_index; i < rrecs; i++) {
2734 error = xfs_btree_check_ptr(cur, lpp, i, level);
2735 if (error)
2736 goto error0;
2737 }
2738#endif
2739
2740 /* Copy the keys & pointers to the new block. */
2741 xfs_btree_copy_keys(cur, rkp, lkp, rrecs);
2742 xfs_btree_copy_ptrs(cur, rpp, lpp, rrecs);
2743
2744 xfs_btree_log_keys(cur, rbp, 1, rrecs);
2745 xfs_btree_log_ptrs(cur, rbp, 1, rrecs);
2746
2747 /* Stash the keys of the new block for later insertion. */
2748 xfs_btree_get_node_keys(cur, right, key);
2749 } else {
2750 /* It's a leaf. Move records. */
2751 union xfs_btree_rec *lrp; /* left record pointer */
2752 union xfs_btree_rec *rrp; /* right record pointer */
2753
2754 lrp = xfs_btree_rec_addr(cur, src_index, left);
2755 rrp = xfs_btree_rec_addr(cur, 1, right);
2756
2757 /* Copy records to the new block. */
2758 xfs_btree_copy_recs(cur, rrp, lrp, rrecs);
2759 xfs_btree_log_recs(cur, rbp, 1, rrecs);
2760
2761 /* Stash the keys of the new block for later insertion. */
2762 xfs_btree_get_leaf_keys(cur, right, key);
2763 }
2764
2765 /*
2766 * Find the left block number by looking in the buffer.
2767 * Adjust sibling pointers.
2768 */
2769 xfs_btree_get_sibling(cur, left, &rrptr, XFS_BB_RIGHTSIB);
2770 xfs_btree_set_sibling(cur, right, &rrptr, XFS_BB_RIGHTSIB);
2771 xfs_btree_set_sibling(cur, right, &lptr, XFS_BB_LEFTSIB);
2772 xfs_btree_set_sibling(cur, left, &rptr, XFS_BB_RIGHTSIB);
2773
2774 xfs_btree_log_block(cur, rbp, XFS_BB_ALL_BITS);
2775 xfs_btree_log_block(cur, lbp, XFS_BB_NUMRECS | XFS_BB_RIGHTSIB);
2776
2777 /*
2778 * If there's a block to the new block's right, make that block
2779 * point back to right instead of to left.
2780 */
2781 if (!xfs_btree_ptr_is_null(cur, &rrptr)) {
2782 error = xfs_btree_read_buf_block(cur, &rrptr,
2783 0, &rrblock, &rrbp);
2784 if (error)
2785 goto error0;
2786 xfs_btree_set_sibling(cur, rrblock, &rptr, XFS_BB_LEFTSIB);
2787 xfs_btree_log_block(cur, rrbp, XFS_BB_LEFTSIB);
2788 }
2789
2790 /* Update the parent high keys of the left block, if needed. */
2791 if (cur->bc_flags & XFS_BTREE_OVERLAPPING) {
2792 error = xfs_btree_update_keys(cur, level);
2793 if (error)
2794 goto error0;
2795 }
2796
2797 /*
2798 * If the cursor is really in the right block, move it there.
2799 * If it's just pointing past the last entry in left, then we'll
2800 * insert there, so don't change anything in that case.
2801 */
2802 if (cur->bc_ptrs[level] > lrecs + 1) {
2803 xfs_btree_setbuf(cur, level, rbp);
2804 cur->bc_ptrs[level] -= lrecs;
2805 }
2806 /*
2807 * If there are more levels, we'll need another cursor which refers
2808 * the right block, no matter where this cursor was.
2809 */
2810 if (level + 1 < cur->bc_nlevels) {
2811 error = xfs_btree_dup_cursor(cur, curp);
2812 if (error)
2813 goto error0;
2814 (*curp)->bc_ptrs[level + 1]++;
2815 }
2816 *ptrp = rptr;
2817 *stat = 1;
2818 return 0;
2819out0:
2820 *stat = 0;
2821 return 0;
2822
2823error0:
2824 return error;
2825}
2826
2827struct xfs_btree_split_args {
2828 struct xfs_btree_cur *cur;
2829 int level;
2830 union xfs_btree_ptr *ptrp;
2831 union xfs_btree_key *key;
2832 struct xfs_btree_cur **curp;
2833 int *stat; /* success/failure */
2834 int result;
2835 bool kswapd; /* allocation in kswapd context */
2836 struct completion *done;
2837 struct work_struct work;
2838};
2839
2840/*
2841 * Stack switching interfaces for allocation
2842 */
2843static void
2844xfs_btree_split_worker(
2845 struct work_struct *work)
2846{
2847 struct xfs_btree_split_args *args = container_of(work,
2848 struct xfs_btree_split_args, work);
2849 unsigned long pflags;
2850 unsigned long new_pflags = PF_MEMALLOC_NOFS;
2851
2852 /*
2853 * we are in a transaction context here, but may also be doing work
2854 * in kswapd context, and hence we may need to inherit that state
2855 * temporarily to ensure that we don't block waiting for memory reclaim
2856 * in any way.
2857 */
2858 if (args->kswapd)
2859 new_pflags |= PF_MEMALLOC | PF_SWAPWRITE | PF_KSWAPD;
2860
2861 current_set_flags_nested(&pflags, new_pflags);
2862
2863 args->result = __xfs_btree_split(args->cur, args->level, args->ptrp,
2864 args->key, args->curp, args->stat);
2865 complete(args->done);
2866
2867 current_restore_flags_nested(&pflags, new_pflags);
2868}
2869
2870/*
2871 * BMBT split requests often come in with little stack to work on. Push
2872 * them off to a worker thread so there is lots of stack to use. For the other
2873 * btree types, just call directly to avoid the context switch overhead here.
2874 */
2875STATIC int /* error */
2876xfs_btree_split(
2877 struct xfs_btree_cur *cur,
2878 int level,
2879 union xfs_btree_ptr *ptrp,
2880 union xfs_btree_key *key,
2881 struct xfs_btree_cur **curp,
2882 int *stat) /* success/failure */
2883{
2884 struct xfs_btree_split_args args;
2885 DECLARE_COMPLETION_ONSTACK(done);
2886
2887 if (cur->bc_btnum != XFS_BTNUM_BMAP)
2888 return __xfs_btree_split(cur, level, ptrp, key, curp, stat);
2889
2890 args.cur = cur;
2891 args.level = level;
2892 args.ptrp = ptrp;
2893 args.key = key;
2894 args.curp = curp;
2895 args.stat = stat;
2896 args.done = &done;
2897 args.kswapd = current_is_kswapd();
2898 INIT_WORK_ONSTACK(&args.work, xfs_btree_split_worker);
2899 queue_work(xfs_alloc_wq, &args.work);
2900 wait_for_completion(&done);
2901 destroy_work_on_stack(&args.work);
2902 return args.result;
2903}
2904
2905
2906/*
2907 * Copy the old inode root contents into a real block and make the
2908 * broot point to it.
2909 */
2910int /* error */
2911xfs_btree_new_iroot(
2912 struct xfs_btree_cur *cur, /* btree cursor */
2913 int *logflags, /* logging flags for inode */
2914 int *stat) /* return status - 0 fail */
2915{
2916 struct xfs_buf *cbp; /* buffer for cblock */
2917 struct xfs_btree_block *block; /* btree block */
2918 struct xfs_btree_block *cblock; /* child btree block */
2919 union xfs_btree_key *ckp; /* child key pointer */
2920 union xfs_btree_ptr *cpp; /* child ptr pointer */
2921 union xfs_btree_key *kp; /* pointer to btree key */
2922 union xfs_btree_ptr *pp; /* pointer to block addr */
2923 union xfs_btree_ptr nptr; /* new block addr */
2924 int level; /* btree level */
2925 int error; /* error return code */
2926#ifdef DEBUG
2927 int i; /* loop counter */
2928#endif
2929
2930 XFS_BTREE_STATS_INC(cur, newroot);
2931
2932 ASSERT(cur->bc_flags & XFS_BTREE_ROOT_IN_INODE);
2933
2934 level = cur->bc_nlevels - 1;
2935
2936 block = xfs_btree_get_iroot(cur);
2937 pp = xfs_btree_ptr_addr(cur, 1, block);
2938
2939 /* Allocate the new block. If we can't do it, we're toast. Give up. */
2940 error = cur->bc_ops->alloc_block(cur, pp, &nptr, stat);
2941 if (error)
2942 goto error0;
2943 if (*stat == 0)
2944 return 0;
2945
2946 XFS_BTREE_STATS_INC(cur, alloc);
2947
2948 /* Copy the root into a real block. */
2949 error = xfs_btree_get_buf_block(cur, &nptr, 0, &cblock, &cbp);
2950 if (error)
2951 goto error0;
2952
2953 /*
2954 * we can't just memcpy() the root in for CRC enabled btree blocks.
2955 * In that case have to also ensure the blkno remains correct
2956 */
2957 memcpy(cblock, block, xfs_btree_block_len(cur));
2958 if (cur->bc_flags & XFS_BTREE_CRC_BLOCKS) {
2959 if (cur->bc_flags & XFS_BTREE_LONG_PTRS)
2960 cblock->bb_u.l.bb_blkno = cpu_to_be64(cbp->b_bn);
2961 else
2962 cblock->bb_u.s.bb_blkno = cpu_to_be64(cbp->b_bn);
2963 }
2964
2965 be16_add_cpu(&block->bb_level, 1);
2966 xfs_btree_set_numrecs(block, 1);
2967 cur->bc_nlevels++;
2968 cur->bc_ptrs[level + 1] = 1;
2969
2970 kp = xfs_btree_key_addr(cur, 1, block);
2971 ckp = xfs_btree_key_addr(cur, 1, cblock);
2972 xfs_btree_copy_keys(cur, ckp, kp, xfs_btree_get_numrecs(cblock));
2973
2974 cpp = xfs_btree_ptr_addr(cur, 1, cblock);
2975#ifdef DEBUG
2976 for (i = 0; i < be16_to_cpu(cblock->bb_numrecs); i++) {
2977 error = xfs_btree_check_ptr(cur, pp, i, level);
2978 if (error)
2979 goto error0;
2980 }
2981#endif
2982 xfs_btree_copy_ptrs(cur, cpp, pp, xfs_btree_get_numrecs(cblock));
2983
2984#ifdef DEBUG
2985 error = xfs_btree_check_ptr(cur, &nptr, 0, level);
2986 if (error)
2987 goto error0;
2988#endif
2989 xfs_btree_copy_ptrs(cur, pp, &nptr, 1);
2990
2991 xfs_iroot_realloc(cur->bc_private.b.ip,
2992 1 - xfs_btree_get_numrecs(cblock),
2993 cur->bc_private.b.whichfork);
2994
2995 xfs_btree_setbuf(cur, level, cbp);
2996
2997 /*
2998 * Do all this logging at the end so that
2999 * the root is at the right level.
3000 */
3001 xfs_btree_log_block(cur, cbp, XFS_BB_ALL_BITS);
3002 xfs_btree_log_keys(cur, cbp, 1, be16_to_cpu(cblock->bb_numrecs));
3003 xfs_btree_log_ptrs(cur, cbp, 1, be16_to_cpu(cblock->bb_numrecs));
3004
3005 *logflags |=
3006 XFS_ILOG_CORE | xfs_ilog_fbroot(cur->bc_private.b.whichfork);
3007 *stat = 1;
3008 return 0;
3009error0:
3010 return error;
3011}
3012
3013/*
3014 * Allocate a new root block, fill it in.
3015 */
3016STATIC int /* error */
3017xfs_btree_new_root(
3018 struct xfs_btree_cur *cur, /* btree cursor */
3019 int *stat) /* success/failure */
3020{
3021 struct xfs_btree_block *block; /* one half of the old root block */
3022 struct xfs_buf *bp; /* buffer containing block */
3023 int error; /* error return value */
3024 struct xfs_buf *lbp; /* left buffer pointer */
3025 struct xfs_btree_block *left; /* left btree block */
3026 struct xfs_buf *nbp; /* new (root) buffer */
3027 struct xfs_btree_block *new; /* new (root) btree block */
3028 int nptr; /* new value for key index, 1 or 2 */
3029 struct xfs_buf *rbp; /* right buffer pointer */
3030 struct xfs_btree_block *right; /* right btree block */
3031 union xfs_btree_ptr rptr;
3032 union xfs_btree_ptr lptr;
3033
3034 XFS_BTREE_STATS_INC(cur, newroot);
3035
3036 /* initialise our start point from the cursor */
3037 cur->bc_ops->init_ptr_from_cur(cur, &rptr);
3038
3039 /* Allocate the new block. If we can't do it, we're toast. Give up. */
3040 error = cur->bc_ops->alloc_block(cur, &rptr, &lptr, stat);
3041 if (error)
3042 goto error0;
3043 if (*stat == 0)
3044 goto out0;
3045 XFS_BTREE_STATS_INC(cur, alloc);
3046
3047 /* Set up the new block. */
3048 error = xfs_btree_get_buf_block(cur, &lptr, 0, &new, &nbp);
3049 if (error)
3050 goto error0;
3051
3052 /* Set the root in the holding structure increasing the level by 1. */
3053 cur->bc_ops->set_root(cur, &lptr, 1);
3054
3055 /*
3056 * At the previous root level there are now two blocks: the old root,
3057 * and the new block generated when it was split. We don't know which
3058 * one the cursor is pointing at, so we set up variables "left" and
3059 * "right" for each case.
3060 */
3061 block = xfs_btree_get_block(cur, cur->bc_nlevels - 1, &bp);
3062
3063#ifdef DEBUG
3064 error = xfs_btree_check_block(cur, block, cur->bc_nlevels - 1, bp);
3065 if (error)
3066 goto error0;
3067#endif
3068
3069 xfs_btree_get_sibling(cur, block, &rptr, XFS_BB_RIGHTSIB);
3070 if (!xfs_btree_ptr_is_null(cur, &rptr)) {
3071 /* Our block is left, pick up the right block. */
3072 lbp = bp;
3073 xfs_btree_buf_to_ptr(cur, lbp, &lptr);
3074 left = block;
3075 error = xfs_btree_read_buf_block(cur, &rptr, 0, &right, &rbp);
3076 if (error)
3077 goto error0;
3078 bp = rbp;
3079 nptr = 1;
3080 } else {
3081 /* Our block is right, pick up the left block. */
3082 rbp = bp;
3083 xfs_btree_buf_to_ptr(cur, rbp, &rptr);
3084 right = block;
3085 xfs_btree_get_sibling(cur, right, &lptr, XFS_BB_LEFTSIB);
3086 error = xfs_btree_read_buf_block(cur, &lptr, 0, &left, &lbp);
3087 if (error)
3088 goto error0;
3089 bp = lbp;
3090 nptr = 2;
3091 }
3092
3093 /* Fill in the new block's btree header and log it. */
3094 xfs_btree_init_block_cur(cur, nbp, cur->bc_nlevels, 2);
3095 xfs_btree_log_block(cur, nbp, XFS_BB_ALL_BITS);
3096 ASSERT(!xfs_btree_ptr_is_null(cur, &lptr) &&
3097 !xfs_btree_ptr_is_null(cur, &rptr));
3098
3099 /* Fill in the key data in the new root. */
3100 if (xfs_btree_get_level(left) > 0) {
3101 /*
3102 * Get the keys for the left block's keys and put them directly
3103 * in the parent block. Do the same for the right block.
3104 */
3105 xfs_btree_get_node_keys(cur, left,
3106 xfs_btree_key_addr(cur, 1, new));
3107 xfs_btree_get_node_keys(cur, right,
3108 xfs_btree_key_addr(cur, 2, new));
3109 } else {
3110 /*
3111 * Get the keys for the left block's records and put them
3112 * directly in the parent block. Do the same for the right
3113 * block.
3114 */
3115 xfs_btree_get_leaf_keys(cur, left,
3116 xfs_btree_key_addr(cur, 1, new));
3117 xfs_btree_get_leaf_keys(cur, right,
3118 xfs_btree_key_addr(cur, 2, new));
3119 }
3120 xfs_btree_log_keys(cur, nbp, 1, 2);
3121
3122 /* Fill in the pointer data in the new root. */
3123 xfs_btree_copy_ptrs(cur,
3124 xfs_btree_ptr_addr(cur, 1, new), &lptr, 1);
3125 xfs_btree_copy_ptrs(cur,
3126 xfs_btree_ptr_addr(cur, 2, new), &rptr, 1);
3127 xfs_btree_log_ptrs(cur, nbp, 1, 2);
3128
3129 /* Fix up the cursor. */
3130 xfs_btree_setbuf(cur, cur->bc_nlevels, nbp);
3131 cur->bc_ptrs[cur->bc_nlevels] = nptr;
3132 cur->bc_nlevels++;
3133 *stat = 1;
3134 return 0;
3135error0:
3136 return error;
3137out0:
3138 *stat = 0;
3139 return 0;
3140}
3141
3142STATIC int
3143xfs_btree_make_block_unfull(
3144 struct xfs_btree_cur *cur, /* btree cursor */
3145 int level, /* btree level */
3146 int numrecs,/* # of recs in block */
3147 int *oindex,/* old tree index */
3148 int *index, /* new tree index */
3149 union xfs_btree_ptr *nptr, /* new btree ptr */
3150 struct xfs_btree_cur **ncur, /* new btree cursor */
3151 union xfs_btree_key *key, /* key of new block */
3152 int *stat)
3153{
3154 int error = 0;
3155
3156 if ((cur->bc_flags & XFS_BTREE_ROOT_IN_INODE) &&
3157 level == cur->bc_nlevels - 1) {
3158 struct xfs_inode *ip = cur->bc_private.b.ip;
3159
3160 if (numrecs < cur->bc_ops->get_dmaxrecs(cur, level)) {
3161 /* A root block that can be made bigger. */
3162 xfs_iroot_realloc(ip, 1, cur->bc_private.b.whichfork);
3163 *stat = 1;
3164 } else {
3165 /* A root block that needs replacing */
3166 int logflags = 0;
3167
3168 error = xfs_btree_new_iroot(cur, &logflags, stat);
3169 if (error || *stat == 0)
3170 return error;
3171
3172 xfs_trans_log_inode(cur->bc_tp, ip, logflags);
3173 }
3174
3175 return 0;
3176 }
3177
3178 /* First, try shifting an entry to the right neighbor. */
3179 error = xfs_btree_rshift(cur, level, stat);
3180 if (error || *stat)
3181 return error;
3182
3183 /* Next, try shifting an entry to the left neighbor. */
3184 error = xfs_btree_lshift(cur, level, stat);
3185 if (error)
3186 return error;
3187
3188 if (*stat) {
3189 *oindex = *index = cur->bc_ptrs[level];
3190 return 0;
3191 }
3192
3193 /*
3194 * Next, try splitting the current block in half.
3195 *
3196 * If this works we have to re-set our variables because we
3197 * could be in a different block now.
3198 */
3199 error = xfs_btree_split(cur, level, nptr, key, ncur, stat);
3200 if (error || *stat == 0)
3201 return error;
3202
3203
3204 *index = cur->bc_ptrs[level];
3205 return 0;
3206}
3207
3208/*
3209 * Insert one record/level. Return information to the caller
3210 * allowing the next level up to proceed if necessary.
3211 */
3212STATIC int
3213xfs_btree_insrec(
3214 struct xfs_btree_cur *cur, /* btree cursor */
3215 int level, /* level to insert record at */
3216 union xfs_btree_ptr *ptrp, /* i/o: block number inserted */
3217 union xfs_btree_rec *rec, /* record to insert */
3218 union xfs_btree_key *key, /* i/o: block key for ptrp */
3219 struct xfs_btree_cur **curp, /* output: new cursor replacing cur */
3220 int *stat) /* success/failure */
3221{
3222 struct xfs_btree_block *block; /* btree block */
3223 struct xfs_buf *bp; /* buffer for block */
3224 union xfs_btree_ptr nptr; /* new block ptr */
3225 struct xfs_btree_cur *ncur; /* new btree cursor */
3226 union xfs_btree_key nkey; /* new block key */
3227 union xfs_btree_key *lkey;
3228 int optr; /* old key/record index */
3229 int ptr; /* key/record index */
3230 int numrecs;/* number of records */
3231 int error; /* error return value */
3232#ifdef DEBUG
3233 int i;
3234#endif
3235 xfs_daddr_t old_bn;
3236
3237 ncur = NULL;
3238 lkey = &nkey;
3239
3240 /*
3241 * If we have an external root pointer, and we've made it to the
3242 * root level, allocate a new root block and we're done.
3243 */
3244 if (!(cur->bc_flags & XFS_BTREE_ROOT_IN_INODE) &&
3245 (level >= cur->bc_nlevels)) {
3246 error = xfs_btree_new_root(cur, stat);
3247 xfs_btree_set_ptr_null(cur, ptrp);
3248
3249 return error;
3250 }
3251
3252 /* If we're off the left edge, return failure. */
3253 ptr = cur->bc_ptrs[level];
3254 if (ptr == 0) {
3255 *stat = 0;
3256 return 0;
3257 }
3258
3259 optr = ptr;
3260
3261 XFS_BTREE_STATS_INC(cur, insrec);
3262
3263 /* Get pointers to the btree buffer and block. */
3264 block = xfs_btree_get_block(cur, level, &bp);
3265 old_bn = bp ? bp->b_bn : XFS_BUF_DADDR_NULL;
3266 numrecs = xfs_btree_get_numrecs(block);
3267
3268#ifdef DEBUG
3269 error = xfs_btree_check_block(cur, block, level, bp);
3270 if (error)
3271 goto error0;
3272
3273 /* Check that the new entry is being inserted in the right place. */
3274 if (ptr <= numrecs) {
3275 if (level == 0) {
3276 ASSERT(cur->bc_ops->recs_inorder(cur, rec,
3277 xfs_btree_rec_addr(cur, ptr, block)));
3278 } else {
3279 ASSERT(cur->bc_ops->keys_inorder(cur, key,
3280 xfs_btree_key_addr(cur, ptr, block)));
3281 }
3282 }
3283#endif
3284
3285 /*
3286 * If the block is full, we can't insert the new entry until we
3287 * make the block un-full.
3288 */
3289 xfs_btree_set_ptr_null(cur, &nptr);
3290 if (numrecs == cur->bc_ops->get_maxrecs(cur, level)) {
3291 error = xfs_btree_make_block_unfull(cur, level, numrecs,
3292 &optr, &ptr, &nptr, &ncur, lkey, stat);
3293 if (error || *stat == 0)
3294 goto error0;
3295 }
3296
3297 /*
3298 * The current block may have changed if the block was
3299 * previously full and we have just made space in it.
3300 */
3301 block = xfs_btree_get_block(cur, level, &bp);
3302 numrecs = xfs_btree_get_numrecs(block);
3303
3304#ifdef DEBUG
3305 error = xfs_btree_check_block(cur, block, level, bp);
3306 if (error)
3307 return error;
3308#endif
3309
3310 /*
3311 * At this point we know there's room for our new entry in the block
3312 * we're pointing at.
3313 */
3314 XFS_BTREE_STATS_ADD(cur, moves, numrecs - ptr + 1);
3315
3316 if (level > 0) {
3317 /* It's a nonleaf. make a hole in the keys and ptrs */
3318 union xfs_btree_key *kp;
3319 union xfs_btree_ptr *pp;
3320
3321 kp = xfs_btree_key_addr(cur, ptr, block);
3322 pp = xfs_btree_ptr_addr(cur, ptr, block);
3323
3324#ifdef DEBUG
3325 for (i = numrecs - ptr; i >= 0; i--) {
3326 error = xfs_btree_check_ptr(cur, pp, i, level);
3327 if (error)
3328 return error;
3329 }
3330#endif
3331
3332 xfs_btree_shift_keys(cur, kp, 1, numrecs - ptr + 1);
3333 xfs_btree_shift_ptrs(cur, pp, 1, numrecs - ptr + 1);
3334
3335#ifdef DEBUG
3336 error = xfs_btree_check_ptr(cur, ptrp, 0, level);
3337 if (error)
3338 goto error0;
3339#endif
3340
3341 /* Now put the new data in, bump numrecs and log it. */
3342 xfs_btree_copy_keys(cur, kp, key, 1);
3343 xfs_btree_copy_ptrs(cur, pp, ptrp, 1);
3344 numrecs++;
3345 xfs_btree_set_numrecs(block, numrecs);
3346 xfs_btree_log_ptrs(cur, bp, ptr, numrecs);
3347 xfs_btree_log_keys(cur, bp, ptr, numrecs);
3348#ifdef DEBUG
3349 if (ptr < numrecs) {
3350 ASSERT(cur->bc_ops->keys_inorder(cur, kp,
3351 xfs_btree_key_addr(cur, ptr + 1, block)));
3352 }
3353#endif
3354 } else {
3355 /* It's a leaf. make a hole in the records */
3356 union xfs_btree_rec *rp;
3357
3358 rp = xfs_btree_rec_addr(cur, ptr, block);
3359
3360 xfs_btree_shift_recs(cur, rp, 1, numrecs - ptr + 1);
3361
3362 /* Now put the new data in, bump numrecs and log it. */
3363 xfs_btree_copy_recs(cur, rp, rec, 1);
3364 xfs_btree_set_numrecs(block, ++numrecs);
3365 xfs_btree_log_recs(cur, bp, ptr, numrecs);
3366#ifdef DEBUG
3367 if (ptr < numrecs) {
3368 ASSERT(cur->bc_ops->recs_inorder(cur, rp,
3369 xfs_btree_rec_addr(cur, ptr + 1, block)));
3370 }
3371#endif
3372 }
3373
3374 /* Log the new number of records in the btree header. */
3375 xfs_btree_log_block(cur, bp, XFS_BB_NUMRECS);
3376
3377 /*
3378 * If we just inserted into a new tree block, we have to
3379 * recalculate nkey here because nkey is out of date.
3380 *
3381 * Otherwise we're just updating an existing block (having shoved
3382 * some records into the new tree block), so use the regular key
3383 * update mechanism.
3384 */
3385 if (bp && bp->b_bn != old_bn) {
3386 xfs_btree_get_keys(cur, block, lkey);
3387 } else if (xfs_btree_needs_key_update(cur, optr)) {
3388 error = xfs_btree_update_keys(cur, level);
3389 if (error)
3390 goto error0;
3391 }
3392
3393 /*
3394 * If we are tracking the last record in the tree and
3395 * we are at the far right edge of the tree, update it.
3396 */
3397 if (xfs_btree_is_lastrec(cur, block, level)) {
3398 cur->bc_ops->update_lastrec(cur, block, rec,
3399 ptr, LASTREC_INSREC);
3400 }
3401
3402 /*
3403 * Return the new block number, if any.
3404 * If there is one, give back a record value and a cursor too.
3405 */
3406 *ptrp = nptr;
3407 if (!xfs_btree_ptr_is_null(cur, &nptr)) {
3408 xfs_btree_copy_keys(cur, key, lkey, 1);
3409 *curp = ncur;
3410 }
3411
3412 *stat = 1;
3413 return 0;
3414
3415error0:
3416 return error;
3417}
3418
3419/*
3420 * Insert the record at the point referenced by cur.
3421 *
3422 * A multi-level split of the tree on insert will invalidate the original
3423 * cursor. All callers of this function should assume that the cursor is
3424 * no longer valid and revalidate it.
3425 */
3426int
3427xfs_btree_insert(
3428 struct xfs_btree_cur *cur,
3429 int *stat)
3430{
3431 int error; /* error return value */
3432 int i; /* result value, 0 for failure */
3433 int level; /* current level number in btree */
3434 union xfs_btree_ptr nptr; /* new block number (split result) */
3435 struct xfs_btree_cur *ncur; /* new cursor (split result) */
3436 struct xfs_btree_cur *pcur; /* previous level's cursor */
3437 union xfs_btree_key bkey; /* key of block to insert */
3438 union xfs_btree_key *key;
3439 union xfs_btree_rec rec; /* record to insert */
3440
3441 level = 0;
3442 ncur = NULL;
3443 pcur = cur;
3444 key = &bkey;
3445
3446 xfs_btree_set_ptr_null(cur, &nptr);
3447
3448 /* Make a key out of the record data to be inserted, and save it. */
3449 cur->bc_ops->init_rec_from_cur(cur, &rec);
3450 cur->bc_ops->init_key_from_rec(key, &rec);
3451
3452 /*
3453 * Loop going up the tree, starting at the leaf level.
3454 * Stop when we don't get a split block, that must mean that
3455 * the insert is finished with this level.
3456 */
3457 do {
3458 /*
3459 * Insert nrec/nptr into this level of the tree.
3460 * Note if we fail, nptr will be null.
3461 */
3462 error = xfs_btree_insrec(pcur, level, &nptr, &rec, key,
3463 &ncur, &i);
3464 if (error) {
3465 if (pcur != cur)
3466 xfs_btree_del_cursor(pcur, XFS_BTREE_ERROR);
3467 goto error0;
3468 }
3469
3470 XFS_WANT_CORRUPTED_GOTO(cur->bc_mp, i == 1, error0);
3471 level++;
3472
3473 /*
3474 * See if the cursor we just used is trash.
3475 * Can't trash the caller's cursor, but otherwise we should
3476 * if ncur is a new cursor or we're about to be done.
3477 */
3478 if (pcur != cur &&
3479 (ncur || xfs_btree_ptr_is_null(cur, &nptr))) {
3480 /* Save the state from the cursor before we trash it */
3481 if (cur->bc_ops->update_cursor)
3482 cur->bc_ops->update_cursor(pcur, cur);
3483 cur->bc_nlevels = pcur->bc_nlevels;
3484 xfs_btree_del_cursor(pcur, XFS_BTREE_NOERROR);
3485 }
3486 /* If we got a new cursor, switch to it. */
3487 if (ncur) {
3488 pcur = ncur;
3489 ncur = NULL;
3490 }
3491 } while (!xfs_btree_ptr_is_null(cur, &nptr));
3492
3493 *stat = i;
3494 return 0;
3495error0:
3496 return error;
3497}
3498
3499/*
3500 * Try to merge a non-leaf block back into the inode root.
3501 *
3502 * Note: the killroot names comes from the fact that we're effectively
3503 * killing the old root block. But because we can't just delete the
3504 * inode we have to copy the single block it was pointing to into the
3505 * inode.
3506 */
3507STATIC int
3508xfs_btree_kill_iroot(
3509 struct xfs_btree_cur *cur)
3510{
3511 int whichfork = cur->bc_private.b.whichfork;
3512 struct xfs_inode *ip = cur->bc_private.b.ip;
3513 struct xfs_ifork *ifp = XFS_IFORK_PTR(ip, whichfork);
3514 struct xfs_btree_block *block;
3515 struct xfs_btree_block *cblock;
3516 union xfs_btree_key *kp;
3517 union xfs_btree_key *ckp;
3518 union xfs_btree_ptr *pp;
3519 union xfs_btree_ptr *cpp;
3520 struct xfs_buf *cbp;
3521 int level;
3522 int index;
3523 int numrecs;
3524 int error;
3525#ifdef DEBUG
3526 union xfs_btree_ptr ptr;
3527 int i;
3528#endif
3529
3530 ASSERT(cur->bc_flags & XFS_BTREE_ROOT_IN_INODE);
3531 ASSERT(cur->bc_nlevels > 1);
3532
3533 /*
3534 * Don't deal with the root block needs to be a leaf case.
3535 * We're just going to turn the thing back into extents anyway.
3536 */
3537 level = cur->bc_nlevels - 1;
3538 if (level == 1)
3539 goto out0;
3540
3541 /*
3542 * Give up if the root has multiple children.
3543 */
3544 block = xfs_btree_get_iroot(cur);
3545 if (xfs_btree_get_numrecs(block) != 1)
3546 goto out0;
3547
3548 cblock = xfs_btree_get_block(cur, level - 1, &cbp);
3549 numrecs = xfs_btree_get_numrecs(cblock);
3550
3551 /*
3552 * Only do this if the next level will fit.
3553 * Then the data must be copied up to the inode,
3554 * instead of freeing the root you free the next level.
3555 */
3556 if (numrecs > cur->bc_ops->get_dmaxrecs(cur, level))
3557 goto out0;
3558
3559 XFS_BTREE_STATS_INC(cur, killroot);
3560
3561#ifdef DEBUG
3562 xfs_btree_get_sibling(cur, block, &ptr, XFS_BB_LEFTSIB);
3563 ASSERT(xfs_btree_ptr_is_null(cur, &ptr));
3564 xfs_btree_get_sibling(cur, block, &ptr, XFS_BB_RIGHTSIB);
3565 ASSERT(xfs_btree_ptr_is_null(cur, &ptr));
3566#endif
3567
3568 index = numrecs - cur->bc_ops->get_maxrecs(cur, level);
3569 if (index) {
3570 xfs_iroot_realloc(cur->bc_private.b.ip, index,
3571 cur->bc_private.b.whichfork);
3572 block = ifp->if_broot;
3573 }
3574
3575 be16_add_cpu(&block->bb_numrecs, index);
3576 ASSERT(block->bb_numrecs == cblock->bb_numrecs);
3577
3578 kp = xfs_btree_key_addr(cur, 1, block);
3579 ckp = xfs_btree_key_addr(cur, 1, cblock);
3580 xfs_btree_copy_keys(cur, kp, ckp, numrecs);
3581
3582 pp = xfs_btree_ptr_addr(cur, 1, block);
3583 cpp = xfs_btree_ptr_addr(cur, 1, cblock);
3584#ifdef DEBUG
3585 for (i = 0; i < numrecs; i++) {
3586 error = xfs_btree_check_ptr(cur, cpp, i, level - 1);
3587 if (error)
3588 return error;
3589 }
3590#endif
3591 xfs_btree_copy_ptrs(cur, pp, cpp, numrecs);
3592
3593 error = xfs_btree_free_block(cur, cbp);
3594 if (error)
3595 return error;
3596
3597 cur->bc_bufs[level - 1] = NULL;
3598 be16_add_cpu(&block->bb_level, -1);
3599 xfs_trans_log_inode(cur->bc_tp, ip,
3600 XFS_ILOG_CORE | xfs_ilog_fbroot(cur->bc_private.b.whichfork));
3601 cur->bc_nlevels--;
3602out0:
3603 return 0;
3604}
3605
3606/*
3607 * Kill the current root node, and replace it with it's only child node.
3608 */
3609STATIC int
3610xfs_btree_kill_root(
3611 struct xfs_btree_cur *cur,
3612 struct xfs_buf *bp,
3613 int level,
3614 union xfs_btree_ptr *newroot)
3615{
3616 int error;
3617
3618 XFS_BTREE_STATS_INC(cur, killroot);
3619
3620 /*
3621 * Update the root pointer, decreasing the level by 1 and then
3622 * free the old root.
3623 */
3624 cur->bc_ops->set_root(cur, newroot, -1);
3625
3626 error = xfs_btree_free_block(cur, bp);
3627 if (error)
3628 return error;
3629
3630 cur->bc_bufs[level] = NULL;
3631 cur->bc_ra[level] = 0;
3632 cur->bc_nlevels--;
3633
3634 return 0;
3635}
3636
3637STATIC int
3638xfs_btree_dec_cursor(
3639 struct xfs_btree_cur *cur,
3640 int level,
3641 int *stat)
3642{
3643 int error;
3644 int i;
3645
3646 if (level > 0) {
3647 error = xfs_btree_decrement(cur, level, &i);
3648 if (error)
3649 return error;
3650 }
3651
3652 *stat = 1;
3653 return 0;
3654}
3655
3656/*
3657 * Single level of the btree record deletion routine.
3658 * Delete record pointed to by cur/level.
3659 * Remove the record from its block then rebalance the tree.
3660 * Return 0 for error, 1 for done, 2 to go on to the next level.
3661 */
3662STATIC int /* error */
3663xfs_btree_delrec(
3664 struct xfs_btree_cur *cur, /* btree cursor */
3665 int level, /* level removing record from */
3666 int *stat) /* fail/done/go-on */
3667{
3668 struct xfs_btree_block *block; /* btree block */
3669 union xfs_btree_ptr cptr; /* current block ptr */
3670 struct xfs_buf *bp; /* buffer for block */
3671 int error; /* error return value */
3672 int i; /* loop counter */
3673 union xfs_btree_ptr lptr; /* left sibling block ptr */
3674 struct xfs_buf *lbp; /* left buffer pointer */
3675 struct xfs_btree_block *left; /* left btree block */
3676 int lrecs = 0; /* left record count */
3677 int ptr; /* key/record index */
3678 union xfs_btree_ptr rptr; /* right sibling block ptr */
3679 struct xfs_buf *rbp; /* right buffer pointer */
3680 struct xfs_btree_block *right; /* right btree block */
3681 struct xfs_btree_block *rrblock; /* right-right btree block */
3682 struct xfs_buf *rrbp; /* right-right buffer pointer */
3683 int rrecs = 0; /* right record count */
3684 struct xfs_btree_cur *tcur; /* temporary btree cursor */
3685 int numrecs; /* temporary numrec count */
3686
3687 tcur = NULL;
3688
3689 /* Get the index of the entry being deleted, check for nothing there. */
3690 ptr = cur->bc_ptrs[level];
3691 if (ptr == 0) {
3692 *stat = 0;
3693 return 0;
3694 }
3695
3696 /* Get the buffer & block containing the record or key/ptr. */
3697 block = xfs_btree_get_block(cur, level, &bp);
3698 numrecs = xfs_btree_get_numrecs(block);
3699
3700#ifdef DEBUG
3701 error = xfs_btree_check_block(cur, block, level, bp);
3702 if (error)
3703 goto error0;
3704#endif
3705
3706 /* Fail if we're off the end of the block. */
3707 if (ptr > numrecs) {
3708 *stat = 0;
3709 return 0;
3710 }
3711
3712 XFS_BTREE_STATS_INC(cur, delrec);
3713 XFS_BTREE_STATS_ADD(cur, moves, numrecs - ptr);
3714
3715 /* Excise the entries being deleted. */
3716 if (level > 0) {
3717 /* It's a nonleaf. operate on keys and ptrs */
3718 union xfs_btree_key *lkp;
3719 union xfs_btree_ptr *lpp;
3720
3721 lkp = xfs_btree_key_addr(cur, ptr + 1, block);
3722 lpp = xfs_btree_ptr_addr(cur, ptr + 1, block);
3723
3724#ifdef DEBUG
3725 for (i = 0; i < numrecs - ptr; i++) {
3726 error = xfs_btree_check_ptr(cur, lpp, i, level);
3727 if (error)
3728 goto error0;
3729 }
3730#endif
3731
3732 if (ptr < numrecs) {
3733 xfs_btree_shift_keys(cur, lkp, -1, numrecs - ptr);
3734 xfs_btree_shift_ptrs(cur, lpp, -1, numrecs - ptr);
3735 xfs_btree_log_keys(cur, bp, ptr, numrecs - 1);
3736 xfs_btree_log_ptrs(cur, bp, ptr, numrecs - 1);
3737 }
3738 } else {
3739 /* It's a leaf. operate on records */
3740 if (ptr < numrecs) {
3741 xfs_btree_shift_recs(cur,
3742 xfs_btree_rec_addr(cur, ptr + 1, block),
3743 -1, numrecs - ptr);
3744 xfs_btree_log_recs(cur, bp, ptr, numrecs - 1);
3745 }
3746 }
3747
3748 /*
3749 * Decrement and log the number of entries in the block.
3750 */
3751 xfs_btree_set_numrecs(block, --numrecs);
3752 xfs_btree_log_block(cur, bp, XFS_BB_NUMRECS);
3753
3754 /*
3755 * If we are tracking the last record in the tree and
3756 * we are at the far right edge of the tree, update it.
3757 */
3758 if (xfs_btree_is_lastrec(cur, block, level)) {
3759 cur->bc_ops->update_lastrec(cur, block, NULL,
3760 ptr, LASTREC_DELREC);
3761 }
3762
3763 /*
3764 * We're at the root level. First, shrink the root block in-memory.
3765 * Try to get rid of the next level down. If we can't then there's
3766 * nothing left to do.
3767 */
3768 if (level == cur->bc_nlevels - 1) {
3769 if (cur->bc_flags & XFS_BTREE_ROOT_IN_INODE) {
3770 xfs_iroot_realloc(cur->bc_private.b.ip, -1,
3771 cur->bc_private.b.whichfork);
3772
3773 error = xfs_btree_kill_iroot(cur);
3774 if (error)
3775 goto error0;
3776
3777 error = xfs_btree_dec_cursor(cur, level, stat);
3778 if (error)
3779 goto error0;
3780 *stat = 1;
3781 return 0;
3782 }
3783
3784 /*
3785 * If this is the root level, and there's only one entry left,
3786 * and it's NOT the leaf level, then we can get rid of this
3787 * level.
3788 */
3789 if (numrecs == 1 && level > 0) {
3790 union xfs_btree_ptr *pp;
3791 /*
3792 * pp is still set to the first pointer in the block.
3793 * Make it the new root of the btree.
3794 */
3795 pp = xfs_btree_ptr_addr(cur, 1, block);
3796 error = xfs_btree_kill_root(cur, bp, level, pp);
3797 if (error)
3798 goto error0;
3799 } else if (level > 0) {
3800 error = xfs_btree_dec_cursor(cur, level, stat);
3801 if (error)
3802 goto error0;
3803 }
3804 *stat = 1;
3805 return 0;
3806 }
3807
3808 /*
3809 * If we deleted the leftmost entry in the block, update the
3810 * key values above us in the tree.
3811 */
3812 if (xfs_btree_needs_key_update(cur, ptr)) {
3813 error = xfs_btree_update_keys(cur, level);
3814 if (error)
3815 goto error0;
3816 }
3817
3818 /*
3819 * If the number of records remaining in the block is at least
3820 * the minimum, we're done.
3821 */
3822 if (numrecs >= cur->bc_ops->get_minrecs(cur, level)) {
3823 error = xfs_btree_dec_cursor(cur, level, stat);
3824 if (error)
3825 goto error0;
3826 return 0;
3827 }
3828
3829 /*
3830 * Otherwise, we have to move some records around to keep the
3831 * tree balanced. Look at the left and right sibling blocks to
3832 * see if we can re-balance by moving only one record.
3833 */
3834 xfs_btree_get_sibling(cur, block, &rptr, XFS_BB_RIGHTSIB);
3835 xfs_btree_get_sibling(cur, block, &lptr, XFS_BB_LEFTSIB);
3836
3837 if (cur->bc_flags & XFS_BTREE_ROOT_IN_INODE) {
3838 /*
3839 * One child of root, need to get a chance to copy its contents
3840 * into the root and delete it. Can't go up to next level,
3841 * there's nothing to delete there.
3842 */
3843 if (xfs_btree_ptr_is_null(cur, &rptr) &&
3844 xfs_btree_ptr_is_null(cur, &lptr) &&
3845 level == cur->bc_nlevels - 2) {
3846 error = xfs_btree_kill_iroot(cur);
3847 if (!error)
3848 error = xfs_btree_dec_cursor(cur, level, stat);
3849 if (error)
3850 goto error0;
3851 return 0;
3852 }
3853 }
3854
3855 ASSERT(!xfs_btree_ptr_is_null(cur, &rptr) ||
3856 !xfs_btree_ptr_is_null(cur, &lptr));
3857
3858 /*
3859 * Duplicate the cursor so our btree manipulations here won't
3860 * disrupt the next level up.
3861 */
3862 error = xfs_btree_dup_cursor(cur, &tcur);
3863 if (error)
3864 goto error0;
3865
3866 /*
3867 * If there's a right sibling, see if it's ok to shift an entry
3868 * out of it.
3869 */
3870 if (!xfs_btree_ptr_is_null(cur, &rptr)) {
3871 /*
3872 * Move the temp cursor to the last entry in the next block.
3873 * Actually any entry but the first would suffice.
3874 */
3875 i = xfs_btree_lastrec(tcur, level);
3876 XFS_WANT_CORRUPTED_GOTO(cur->bc_mp, i == 1, error0);
3877
3878 error = xfs_btree_increment(tcur, level, &i);
3879 if (error)
3880 goto error0;
3881 XFS_WANT_CORRUPTED_GOTO(cur->bc_mp, i == 1, error0);
3882
3883 i = xfs_btree_lastrec(tcur, level);
3884 XFS_WANT_CORRUPTED_GOTO(cur->bc_mp, i == 1, error0);
3885
3886 /* Grab a pointer to the block. */
3887 right = xfs_btree_get_block(tcur, level, &rbp);
3888#ifdef DEBUG
3889 error = xfs_btree_check_block(tcur, right, level, rbp);
3890 if (error)
3891 goto error0;
3892#endif
3893 /* Grab the current block number, for future use. */
3894 xfs_btree_get_sibling(tcur, right, &cptr, XFS_BB_LEFTSIB);
3895
3896 /*
3897 * If right block is full enough so that removing one entry
3898 * won't make it too empty, and left-shifting an entry out
3899 * of right to us works, we're done.
3900 */
3901 if (xfs_btree_get_numrecs(right) - 1 >=
3902 cur->bc_ops->get_minrecs(tcur, level)) {
3903 error = xfs_btree_lshift(tcur, level, &i);
3904 if (error)
3905 goto error0;
3906 if (i) {
3907 ASSERT(xfs_btree_get_numrecs(block) >=
3908 cur->bc_ops->get_minrecs(tcur, level));
3909
3910 xfs_btree_del_cursor(tcur, XFS_BTREE_NOERROR);
3911 tcur = NULL;
3912
3913 error = xfs_btree_dec_cursor(cur, level, stat);
3914 if (error)
3915 goto error0;
3916 return 0;
3917 }
3918 }
3919
3920 /*
3921 * Otherwise, grab the number of records in right for
3922 * future reference, and fix up the temp cursor to point
3923 * to our block again (last record).
3924 */
3925 rrecs = xfs_btree_get_numrecs(right);
3926 if (!xfs_btree_ptr_is_null(cur, &lptr)) {
3927 i = xfs_btree_firstrec(tcur, level);
3928 XFS_WANT_CORRUPTED_GOTO(cur->bc_mp, i == 1, error0);
3929
3930 error = xfs_btree_decrement(tcur, level, &i);
3931 if (error)
3932 goto error0;
3933 XFS_WANT_CORRUPTED_GOTO(cur->bc_mp, i == 1, error0);
3934 }
3935 }
3936
3937 /*
3938 * If there's a left sibling, see if it's ok to shift an entry
3939 * out of it.
3940 */
3941 if (!xfs_btree_ptr_is_null(cur, &lptr)) {
3942 /*
3943 * Move the temp cursor to the first entry in the
3944 * previous block.
3945 */
3946 i = xfs_btree_firstrec(tcur, level);
3947 XFS_WANT_CORRUPTED_GOTO(cur->bc_mp, i == 1, error0);
3948
3949 error = xfs_btree_decrement(tcur, level, &i);
3950 if (error)
3951 goto error0;
3952 i = xfs_btree_firstrec(tcur, level);
3953 XFS_WANT_CORRUPTED_GOTO(cur->bc_mp, i == 1, error0);
3954
3955 /* Grab a pointer to the block. */
3956 left = xfs_btree_get_block(tcur, level, &lbp);
3957#ifdef DEBUG
3958 error = xfs_btree_check_block(cur, left, level, lbp);
3959 if (error)
3960 goto error0;
3961#endif
3962 /* Grab the current block number, for future use. */
3963 xfs_btree_get_sibling(tcur, left, &cptr, XFS_BB_RIGHTSIB);
3964
3965 /*
3966 * If left block is full enough so that removing one entry
3967 * won't make it too empty, and right-shifting an entry out
3968 * of left to us works, we're done.
3969 */
3970 if (xfs_btree_get_numrecs(left) - 1 >=
3971 cur->bc_ops->get_minrecs(tcur, level)) {
3972 error = xfs_btree_rshift(tcur, level, &i);
3973 if (error)
3974 goto error0;
3975 if (i) {
3976 ASSERT(xfs_btree_get_numrecs(block) >=
3977 cur->bc_ops->get_minrecs(tcur, level));
3978 xfs_btree_del_cursor(tcur, XFS_BTREE_NOERROR);
3979 tcur = NULL;
3980 if (level == 0)
3981 cur->bc_ptrs[0]++;
3982
3983 *stat = 1;
3984 return 0;
3985 }
3986 }
3987
3988 /*
3989 * Otherwise, grab the number of records in right for
3990 * future reference.
3991 */
3992 lrecs = xfs_btree_get_numrecs(left);
3993 }
3994
3995 /* Delete the temp cursor, we're done with it. */
3996 xfs_btree_del_cursor(tcur, XFS_BTREE_NOERROR);
3997 tcur = NULL;
3998
3999 /* If here, we need to do a join to keep the tree balanced. */
4000 ASSERT(!xfs_btree_ptr_is_null(cur, &cptr));
4001
4002 if (!xfs_btree_ptr_is_null(cur, &lptr) &&
4003 lrecs + xfs_btree_get_numrecs(block) <=
4004 cur->bc_ops->get_maxrecs(cur, level)) {
4005 /*
4006 * Set "right" to be the starting block,
4007 * "left" to be the left neighbor.
4008 */
4009 rptr = cptr;
4010 right = block;
4011 rbp = bp;
4012 error = xfs_btree_read_buf_block(cur, &lptr, 0, &left, &lbp);
4013 if (error)
4014 goto error0;
4015
4016 /*
4017 * If that won't work, see if we can join with the right neighbor block.
4018 */
4019 } else if (!xfs_btree_ptr_is_null(cur, &rptr) &&
4020 rrecs + xfs_btree_get_numrecs(block) <=
4021 cur->bc_ops->get_maxrecs(cur, level)) {
4022 /*
4023 * Set "left" to be the starting block,
4024 * "right" to be the right neighbor.
4025 */
4026 lptr = cptr;
4027 left = block;
4028 lbp = bp;
4029 error = xfs_btree_read_buf_block(cur, &rptr, 0, &right, &rbp);
4030 if (error)
4031 goto error0;
4032
4033 /*
4034 * Otherwise, we can't fix the imbalance.
4035 * Just return. This is probably a logic error, but it's not fatal.
4036 */
4037 } else {
4038 error = xfs_btree_dec_cursor(cur, level, stat);
4039 if (error)
4040 goto error0;
4041 return 0;
4042 }
4043
4044 rrecs = xfs_btree_get_numrecs(right);
4045 lrecs = xfs_btree_get_numrecs(left);
4046
4047 /*
4048 * We're now going to join "left" and "right" by moving all the stuff
4049 * in "right" to "left" and deleting "right".
4050 */
4051 XFS_BTREE_STATS_ADD(cur, moves, rrecs);
4052 if (level > 0) {
4053 /* It's a non-leaf. Move keys and pointers. */
4054 union xfs_btree_key *lkp; /* left btree key */
4055 union xfs_btree_ptr *lpp; /* left address pointer */
4056 union xfs_btree_key *rkp; /* right btree key */
4057 union xfs_btree_ptr *rpp; /* right address pointer */
4058
4059 lkp = xfs_btree_key_addr(cur, lrecs + 1, left);
4060 lpp = xfs_btree_ptr_addr(cur, lrecs + 1, left);
4061 rkp = xfs_btree_key_addr(cur, 1, right);
4062 rpp = xfs_btree_ptr_addr(cur, 1, right);
4063#ifdef DEBUG
4064 for (i = 1; i < rrecs; i++) {
4065 error = xfs_btree_check_ptr(cur, rpp, i, level);
4066 if (error)
4067 goto error0;
4068 }
4069#endif
4070 xfs_btree_copy_keys(cur, lkp, rkp, rrecs);
4071 xfs_btree_copy_ptrs(cur, lpp, rpp, rrecs);
4072
4073 xfs_btree_log_keys(cur, lbp, lrecs + 1, lrecs + rrecs);
4074 xfs_btree_log_ptrs(cur, lbp, lrecs + 1, lrecs + rrecs);
4075 } else {
4076 /* It's a leaf. Move records. */
4077 union xfs_btree_rec *lrp; /* left record pointer */
4078 union xfs_btree_rec *rrp; /* right record pointer */
4079
4080 lrp = xfs_btree_rec_addr(cur, lrecs + 1, left);
4081 rrp = xfs_btree_rec_addr(cur, 1, right);
4082
4083 xfs_btree_copy_recs(cur, lrp, rrp, rrecs);
4084 xfs_btree_log_recs(cur, lbp, lrecs + 1, lrecs + rrecs);
4085 }
4086
4087 XFS_BTREE_STATS_INC(cur, join);
4088
4089 /*
4090 * Fix up the number of records and right block pointer in the
4091 * surviving block, and log it.
4092 */
4093 xfs_btree_set_numrecs(left, lrecs + rrecs);
4094 xfs_btree_get_sibling(cur, right, &cptr, XFS_BB_RIGHTSIB),
4095 xfs_btree_set_sibling(cur, left, &cptr, XFS_BB_RIGHTSIB);
4096 xfs_btree_log_block(cur, lbp, XFS_BB_NUMRECS | XFS_BB_RIGHTSIB);
4097
4098 /* If there is a right sibling, point it to the remaining block. */
4099 xfs_btree_get_sibling(cur, left, &cptr, XFS_BB_RIGHTSIB);
4100 if (!xfs_btree_ptr_is_null(cur, &cptr)) {
4101 error = xfs_btree_read_buf_block(cur, &cptr, 0, &rrblock, &rrbp);
4102 if (error)
4103 goto error0;
4104 xfs_btree_set_sibling(cur, rrblock, &lptr, XFS_BB_LEFTSIB);
4105 xfs_btree_log_block(cur, rrbp, XFS_BB_LEFTSIB);
4106 }
4107
4108 /* Free the deleted block. */
4109 error = xfs_btree_free_block(cur, rbp);
4110 if (error)
4111 goto error0;
4112
4113 /*
4114 * If we joined with the left neighbor, set the buffer in the
4115 * cursor to the left block, and fix up the index.
4116 */
4117 if (bp != lbp) {
4118 cur->bc_bufs[level] = lbp;
4119 cur->bc_ptrs[level] += lrecs;
4120 cur->bc_ra[level] = 0;
4121 }
4122 /*
4123 * If we joined with the right neighbor and there's a level above
4124 * us, increment the cursor at that level.
4125 */
4126 else if ((cur->bc_flags & XFS_BTREE_ROOT_IN_INODE) ||
4127 (level + 1 < cur->bc_nlevels)) {
4128 error = xfs_btree_increment(cur, level + 1, &i);
4129 if (error)
4130 goto error0;
4131 }
4132
4133 /*
4134 * Readjust the ptr at this level if it's not a leaf, since it's
4135 * still pointing at the deletion point, which makes the cursor
4136 * inconsistent. If this makes the ptr 0, the caller fixes it up.
4137 * We can't use decrement because it would change the next level up.
4138 */
4139 if (level > 0)
4140 cur->bc_ptrs[level]--;
4141
4142 /*
4143 * We combined blocks, so we have to update the parent keys if the
4144 * btree supports overlapped intervals. However, bc_ptrs[level + 1]
4145 * points to the old block so that the caller knows which record to
4146 * delete. Therefore, the caller must be savvy enough to call updkeys
4147 * for us if we return stat == 2. The other exit points from this
4148 * function don't require deletions further up the tree, so they can
4149 * call updkeys directly.
4150 */
4151
4152 /* Return value means the next level up has something to do. */
4153 *stat = 2;
4154 return 0;
4155
4156error0:
4157 if (tcur)
4158 xfs_btree_del_cursor(tcur, XFS_BTREE_ERROR);
4159 return error;
4160}
4161
4162/*
4163 * Delete the record pointed to by cur.
4164 * The cursor refers to the place where the record was (could be inserted)
4165 * when the operation returns.
4166 */
4167int /* error */
4168xfs_btree_delete(
4169 struct xfs_btree_cur *cur,
4170 int *stat) /* success/failure */
4171{
4172 int error; /* error return value */
4173 int level;
4174 int i;
4175 bool joined = false;
4176
4177 /*
4178 * Go up the tree, starting at leaf level.
4179 *
4180 * If 2 is returned then a join was done; go to the next level.
4181 * Otherwise we are done.
4182 */
4183 for (level = 0, i = 2; i == 2; level++) {
4184 error = xfs_btree_delrec(cur, level, &i);
4185 if (error)
4186 goto error0;
4187 if (i == 2)
4188 joined = true;
4189 }
4190
4191 /*
4192 * If we combined blocks as part of deleting the record, delrec won't
4193 * have updated the parent high keys so we have to do that here.
4194 */
4195 if (joined && (cur->bc_flags & XFS_BTREE_OVERLAPPING)) {
4196 error = xfs_btree_updkeys_force(cur, 0);
4197 if (error)
4198 goto error0;
4199 }
4200
4201 if (i == 0) {
4202 for (level = 1; level < cur->bc_nlevels; level++) {
4203 if (cur->bc_ptrs[level] == 0) {
4204 error = xfs_btree_decrement(cur, level, &i);
4205 if (error)
4206 goto error0;
4207 break;
4208 }
4209 }
4210 }
4211
4212 *stat = i;
4213 return 0;
4214error0:
4215 return error;
4216}
4217
4218/*
4219 * Get the data from the pointed-to record.
4220 */
4221int /* error */
4222xfs_btree_get_rec(
4223 struct xfs_btree_cur *cur, /* btree cursor */
4224 union xfs_btree_rec **recp, /* output: btree record */
4225 int *stat) /* output: success/failure */
4226{
4227 struct xfs_btree_block *block; /* btree block */
4228 struct xfs_buf *bp; /* buffer pointer */
4229 int ptr; /* record number */
4230#ifdef DEBUG
4231 int error; /* error return value */
4232#endif
4233
4234 ptr = cur->bc_ptrs[0];
4235 block = xfs_btree_get_block(cur, 0, &bp);
4236
4237#ifdef DEBUG
4238 error = xfs_btree_check_block(cur, block, 0, bp);
4239 if (error)
4240 return error;
4241#endif
4242
4243 /*
4244 * Off the right end or left end, return failure.
4245 */
4246 if (ptr > xfs_btree_get_numrecs(block) || ptr <= 0) {
4247 *stat = 0;
4248 return 0;
4249 }
4250
4251 /*
4252 * Point to the record and extract its data.
4253 */
4254 *recp = xfs_btree_rec_addr(cur, ptr, block);
4255 *stat = 1;
4256 return 0;
4257}
4258
4259/* Visit a block in a btree. */
4260STATIC int
4261xfs_btree_visit_block(
4262 struct xfs_btree_cur *cur,
4263 int level,
4264 xfs_btree_visit_blocks_fn fn,
4265 void *data)
4266{
4267 struct xfs_btree_block *block;
4268 struct xfs_buf *bp;
4269 union xfs_btree_ptr rptr;
4270 int error;
4271
4272 /* do right sibling readahead */
4273 xfs_btree_readahead(cur, level, XFS_BTCUR_RIGHTRA);
4274 block = xfs_btree_get_block(cur, level, &bp);
4275
4276 /* process the block */
4277 error = fn(cur, level, data);
4278 if (error)
4279 return error;
4280
4281 /* now read rh sibling block for next iteration */
4282 xfs_btree_get_sibling(cur, block, &rptr, XFS_BB_RIGHTSIB);
4283 if (xfs_btree_ptr_is_null(cur, &rptr))
4284 return -ENOENT;
4285
4286 return xfs_btree_lookup_get_block(cur, level, &rptr, &block);
4287}
4288
4289
4290/* Visit every block in a btree. */
4291int
4292xfs_btree_visit_blocks(
4293 struct xfs_btree_cur *cur,
4294 xfs_btree_visit_blocks_fn fn,
4295 void *data)
4296{
4297 union xfs_btree_ptr lptr;
4298 int level;
4299 struct xfs_btree_block *block = NULL;
4300 int error = 0;
4301
4302 cur->bc_ops->init_ptr_from_cur(cur, &lptr);
4303
4304 /* for each level */
4305 for (level = cur->bc_nlevels - 1; level >= 0; level--) {
4306 /* grab the left hand block */
4307 error = xfs_btree_lookup_get_block(cur, level, &lptr, &block);
4308 if (error)
4309 return error;
4310
4311 /* readahead the left most block for the next level down */
4312 if (level > 0) {
4313 union xfs_btree_ptr *ptr;
4314
4315 ptr = xfs_btree_ptr_addr(cur, 1, block);
4316 xfs_btree_readahead_ptr(cur, ptr, 1);
4317
4318 /* save for the next iteration of the loop */
4319 xfs_btree_copy_ptrs(cur, &lptr, ptr, 1);
4320 }
4321
4322 /* for each buffer in the level */
4323 do {
4324 error = xfs_btree_visit_block(cur, level, fn, data);
4325 } while (!error);
4326
4327 if (error != -ENOENT)
4328 return error;
4329 }
4330
4331 return 0;
4332}
4333
4334/*
4335 * Change the owner of a btree.
4336 *
4337 * The mechanism we use here is ordered buffer logging. Because we don't know
4338 * how many buffers were are going to need to modify, we don't really want to
4339 * have to make transaction reservations for the worst case of every buffer in a
4340 * full size btree as that may be more space that we can fit in the log....
4341 *
4342 * We do the btree walk in the most optimal manner possible - we have sibling
4343 * pointers so we can just walk all the blocks on each level from left to right
4344 * in a single pass, and then move to the next level and do the same. We can
4345 * also do readahead on the sibling pointers to get IO moving more quickly,
4346 * though for slow disks this is unlikely to make much difference to performance
4347 * as the amount of CPU work we have to do before moving to the next block is
4348 * relatively small.
4349 *
4350 * For each btree block that we load, modify the owner appropriately, set the
4351 * buffer as an ordered buffer and log it appropriately. We need to ensure that
4352 * we mark the region we change dirty so that if the buffer is relogged in
4353 * a subsequent transaction the changes we make here as an ordered buffer are
4354 * correctly relogged in that transaction. If we are in recovery context, then
4355 * just queue the modified buffer as delayed write buffer so the transaction
4356 * recovery completion writes the changes to disk.
4357 */
4358struct xfs_btree_block_change_owner_info {
4359 uint64_t new_owner;
4360 struct list_head *buffer_list;
4361};
4362
4363static int
4364xfs_btree_block_change_owner(
4365 struct xfs_btree_cur *cur,
4366 int level,
4367 void *data)
4368{
4369 struct xfs_btree_block_change_owner_info *bbcoi = data;
4370 struct xfs_btree_block *block;
4371 struct xfs_buf *bp;
4372
4373 /* modify the owner */
4374 block = xfs_btree_get_block(cur, level, &bp);
4375 if (cur->bc_flags & XFS_BTREE_LONG_PTRS) {
4376 if (block->bb_u.l.bb_owner == cpu_to_be64(bbcoi->new_owner))
4377 return 0;
4378 block->bb_u.l.bb_owner = cpu_to_be64(bbcoi->new_owner);
4379 } else {
4380 if (block->bb_u.s.bb_owner == cpu_to_be32(bbcoi->new_owner))
4381 return 0;
4382 block->bb_u.s.bb_owner = cpu_to_be32(bbcoi->new_owner);
4383 }
4384
4385 /*
4386 * If the block is a root block hosted in an inode, we might not have a
4387 * buffer pointer here and we shouldn't attempt to log the change as the
4388 * information is already held in the inode and discarded when the root
4389 * block is formatted into the on-disk inode fork. We still change it,
4390 * though, so everything is consistent in memory.
4391 */
4392 if (!bp) {
4393 ASSERT(cur->bc_flags & XFS_BTREE_ROOT_IN_INODE);
4394 ASSERT(level == cur->bc_nlevels - 1);
4395 return 0;
4396 }
4397
4398 if (cur->bc_tp) {
4399 if (!xfs_trans_ordered_buf(cur->bc_tp, bp)) {
4400 xfs_btree_log_block(cur, bp, XFS_BB_OWNER);
4401 return -EAGAIN;
4402 }
4403 } else {
4404 xfs_buf_delwri_queue(bp, bbcoi->buffer_list);
4405 }
4406
4407 return 0;
4408}
4409
4410int
4411xfs_btree_change_owner(
4412 struct xfs_btree_cur *cur,
4413 uint64_t new_owner,
4414 struct list_head *buffer_list)
4415{
4416 struct xfs_btree_block_change_owner_info bbcoi;
4417
4418 bbcoi.new_owner = new_owner;
4419 bbcoi.buffer_list = buffer_list;
4420
4421 return xfs_btree_visit_blocks(cur, xfs_btree_block_change_owner,
4422 &bbcoi);
4423}
4424
4425/* Verify the v5 fields of a long-format btree block. */
4426xfs_failaddr_t
4427xfs_btree_lblock_v5hdr_verify(
4428 struct xfs_buf *bp,
4429 uint64_t owner)
4430{
4431 struct xfs_mount *mp = bp->b_target->bt_mount;
4432 struct xfs_btree_block *block = XFS_BUF_TO_BLOCK(bp);
4433
4434 if (!xfs_sb_version_hascrc(&mp->m_sb))
4435 return __this_address;
4436 if (!uuid_equal(&block->bb_u.l.bb_uuid, &mp->m_sb.sb_meta_uuid))
4437 return __this_address;
4438 if (block->bb_u.l.bb_blkno != cpu_to_be64(bp->b_bn))
4439 return __this_address;
4440 if (owner != XFS_RMAP_OWN_UNKNOWN &&
4441 be64_to_cpu(block->bb_u.l.bb_owner) != owner)
4442 return __this_address;
4443 return NULL;
4444}
4445
4446/* Verify a long-format btree block. */
4447xfs_failaddr_t
4448xfs_btree_lblock_verify(
4449 struct xfs_buf *bp,
4450 unsigned int max_recs)
4451{
4452 struct xfs_mount *mp = bp->b_target->bt_mount;
4453 struct xfs_btree_block *block = XFS_BUF_TO_BLOCK(bp);
4454
4455 /* numrecs verification */
4456 if (be16_to_cpu(block->bb_numrecs) > max_recs)
4457 return __this_address;
4458
4459 /* sibling pointer verification */
4460 if (block->bb_u.l.bb_leftsib != cpu_to_be64(NULLFSBLOCK) &&
4461 !xfs_verify_fsbno(mp, be64_to_cpu(block->bb_u.l.bb_leftsib)))
4462 return __this_address;
4463 if (block->bb_u.l.bb_rightsib != cpu_to_be64(NULLFSBLOCK) &&
4464 !xfs_verify_fsbno(mp, be64_to_cpu(block->bb_u.l.bb_rightsib)))
4465 return __this_address;
4466
4467 return NULL;
4468}
4469
4470/**
4471 * xfs_btree_sblock_v5hdr_verify() -- verify the v5 fields of a short-format
4472 * btree block
4473 *
4474 * @bp: buffer containing the btree block
4475 * @max_recs: pointer to the m_*_mxr max records field in the xfs mount
4476 * @pag_max_level: pointer to the per-ag max level field
4477 */
4478xfs_failaddr_t
4479xfs_btree_sblock_v5hdr_verify(
4480 struct xfs_buf *bp)
4481{
4482 struct xfs_mount *mp = bp->b_target->bt_mount;
4483 struct xfs_btree_block *block = XFS_BUF_TO_BLOCK(bp);
4484 struct xfs_perag *pag = bp->b_pag;
4485
4486 if (!xfs_sb_version_hascrc(&mp->m_sb))
4487 return __this_address;
4488 if (!uuid_equal(&block->bb_u.s.bb_uuid, &mp->m_sb.sb_meta_uuid))
4489 return __this_address;
4490 if (block->bb_u.s.bb_blkno != cpu_to_be64(bp->b_bn))
4491 return __this_address;
4492 if (pag && be32_to_cpu(block->bb_u.s.bb_owner) != pag->pag_agno)
4493 return __this_address;
4494 return NULL;
4495}
4496
4497/**
4498 * xfs_btree_sblock_verify() -- verify a short-format btree block
4499 *
4500 * @bp: buffer containing the btree block
4501 * @max_recs: maximum records allowed in this btree node
4502 */
4503xfs_failaddr_t
4504xfs_btree_sblock_verify(
4505 struct xfs_buf *bp,
4506 unsigned int max_recs)
4507{
4508 struct xfs_mount *mp = bp->b_target->bt_mount;
4509 struct xfs_btree_block *block = XFS_BUF_TO_BLOCK(bp);
4510 xfs_agblock_t agno;
4511
4512 /* numrecs verification */
4513 if (be16_to_cpu(block->bb_numrecs) > max_recs)
4514 return __this_address;
4515
4516 /* sibling pointer verification */
4517 agno = xfs_daddr_to_agno(mp, XFS_BUF_ADDR(bp));
4518 if (block->bb_u.s.bb_leftsib != cpu_to_be32(NULLAGBLOCK) &&
4519 !xfs_verify_agbno(mp, agno, be32_to_cpu(block->bb_u.s.bb_leftsib)))
4520 return __this_address;
4521 if (block->bb_u.s.bb_rightsib != cpu_to_be32(NULLAGBLOCK) &&
4522 !xfs_verify_agbno(mp, agno, be32_to_cpu(block->bb_u.s.bb_rightsib)))
4523 return __this_address;
4524
4525 return NULL;
4526}
4527
4528/*
4529 * Calculate the number of btree levels needed to store a given number of
4530 * records in a short-format btree.
4531 */
4532uint
4533xfs_btree_compute_maxlevels(
4534 uint *limits,
4535 unsigned long len)
4536{
4537 uint level;
4538 unsigned long maxblocks;
4539
4540 maxblocks = (len + limits[0] - 1) / limits[0];
4541 for (level = 1; maxblocks > 1; level++)
4542 maxblocks = (maxblocks + limits[1] - 1) / limits[1];
4543 return level;
4544}
4545
4546/*
4547 * Query a regular btree for all records overlapping a given interval.
4548 * Start with a LE lookup of the key of low_rec and return all records
4549 * until we find a record with a key greater than the key of high_rec.
4550 */
4551STATIC int
4552xfs_btree_simple_query_range(
4553 struct xfs_btree_cur *cur,
4554 union xfs_btree_key *low_key,
4555 union xfs_btree_key *high_key,
4556 xfs_btree_query_range_fn fn,
4557 void *priv)
4558{
4559 union xfs_btree_rec *recp;
4560 union xfs_btree_key rec_key;
4561 int64_t diff;
4562 int stat;
4563 bool firstrec = true;
4564 int error;
4565
4566 ASSERT(cur->bc_ops->init_high_key_from_rec);
4567 ASSERT(cur->bc_ops->diff_two_keys);
4568
4569 /*
4570 * Find the leftmost record. The btree cursor must be set
4571 * to the low record used to generate low_key.
4572 */
4573 stat = 0;
4574 error = xfs_btree_lookup(cur, XFS_LOOKUP_LE, &stat);
4575 if (error)
4576 goto out;
4577
4578 /* Nothing? See if there's anything to the right. */
4579 if (!stat) {
4580 error = xfs_btree_increment(cur, 0, &stat);
4581 if (error)
4582 goto out;
4583 }
4584
4585 while (stat) {
4586 /* Find the record. */
4587 error = xfs_btree_get_rec(cur, &recp, &stat);
4588 if (error || !stat)
4589 break;
4590
4591 /* Skip if high_key(rec) < low_key. */
4592 if (firstrec) {
4593 cur->bc_ops->init_high_key_from_rec(&rec_key, recp);
4594 firstrec = false;
4595 diff = cur->bc_ops->diff_two_keys(cur, low_key,
4596 &rec_key);
4597 if (diff > 0)
4598 goto advloop;
4599 }
4600
4601 /* Stop if high_key < low_key(rec). */
4602 cur->bc_ops->init_key_from_rec(&rec_key, recp);
4603 diff = cur->bc_ops->diff_two_keys(cur, &rec_key, high_key);
4604 if (diff > 0)
4605 break;
4606
4607 /* Callback */
4608 error = fn(cur, recp, priv);
4609 if (error < 0 || error == XFS_BTREE_QUERY_RANGE_ABORT)
4610 break;
4611
4612advloop:
4613 /* Move on to the next record. */
4614 error = xfs_btree_increment(cur, 0, &stat);
4615 if (error)
4616 break;
4617 }
4618
4619out:
4620 return error;
4621}
4622
4623/*
4624 * Query an overlapped interval btree for all records overlapping a given
4625 * interval. This function roughly follows the algorithm given in
4626 * "Interval Trees" of _Introduction to Algorithms_, which is section
4627 * 14.3 in the 2nd and 3rd editions.
4628 *
4629 * First, generate keys for the low and high records passed in.
4630 *
4631 * For any leaf node, generate the high and low keys for the record.
4632 * If the record keys overlap with the query low/high keys, pass the
4633 * record to the function iterator.
4634 *
4635 * For any internal node, compare the low and high keys of each
4636 * pointer against the query low/high keys. If there's an overlap,
4637 * follow the pointer.
4638 *
4639 * As an optimization, we stop scanning a block when we find a low key
4640 * that is greater than the query's high key.
4641 */
4642STATIC int
4643xfs_btree_overlapped_query_range(
4644 struct xfs_btree_cur *cur,
4645 union xfs_btree_key *low_key,
4646 union xfs_btree_key *high_key,
4647 xfs_btree_query_range_fn fn,
4648 void *priv)
4649{
4650 union xfs_btree_ptr ptr;
4651 union xfs_btree_ptr *pp;
4652 union xfs_btree_key rec_key;
4653 union xfs_btree_key rec_hkey;
4654 union xfs_btree_key *lkp;
4655 union xfs_btree_key *hkp;
4656 union xfs_btree_rec *recp;
4657 struct xfs_btree_block *block;
4658 int64_t ldiff;
4659 int64_t hdiff;
4660 int level;
4661 struct xfs_buf *bp;
4662 int i;
4663 int error;
4664
4665 /* Load the root of the btree. */
4666 level = cur->bc_nlevels - 1;
4667 cur->bc_ops->init_ptr_from_cur(cur, &ptr);
4668 error = xfs_btree_lookup_get_block(cur, level, &ptr, &block);
4669 if (error)
4670 return error;
4671 xfs_btree_get_block(cur, level, &bp);
4672 trace_xfs_btree_overlapped_query_range(cur, level, bp);
4673#ifdef DEBUG
4674 error = xfs_btree_check_block(cur, block, level, bp);
4675 if (error)
4676 goto out;
4677#endif
4678 cur->bc_ptrs[level] = 1;
4679
4680 while (level < cur->bc_nlevels) {
4681 block = xfs_btree_get_block(cur, level, &bp);
4682
4683 /* End of node, pop back towards the root. */
4684 if (cur->bc_ptrs[level] > be16_to_cpu(block->bb_numrecs)) {
4685pop_up:
4686 if (level < cur->bc_nlevels - 1)
4687 cur->bc_ptrs[level + 1]++;
4688 level++;
4689 continue;
4690 }
4691
4692 if (level == 0) {
4693 /* Handle a leaf node. */
4694 recp = xfs_btree_rec_addr(cur, cur->bc_ptrs[0], block);
4695
4696 cur->bc_ops->init_high_key_from_rec(&rec_hkey, recp);
4697 ldiff = cur->bc_ops->diff_two_keys(cur, &rec_hkey,
4698 low_key);
4699
4700 cur->bc_ops->init_key_from_rec(&rec_key, recp);
4701 hdiff = cur->bc_ops->diff_two_keys(cur, high_key,
4702 &rec_key);
4703
4704 /*
4705 * If (record's high key >= query's low key) and
4706 * (query's high key >= record's low key), then
4707 * this record overlaps the query range; callback.
4708 */
4709 if (ldiff >= 0 && hdiff >= 0) {
4710 error = fn(cur, recp, priv);
4711 if (error < 0 ||
4712 error == XFS_BTREE_QUERY_RANGE_ABORT)
4713 break;
4714 } else if (hdiff < 0) {
4715 /* Record is larger than high key; pop. */
4716 goto pop_up;
4717 }
4718 cur->bc_ptrs[level]++;
4719 continue;
4720 }
4721
4722 /* Handle an internal node. */
4723 lkp = xfs_btree_key_addr(cur, cur->bc_ptrs[level], block);
4724 hkp = xfs_btree_high_key_addr(cur, cur->bc_ptrs[level], block);
4725 pp = xfs_btree_ptr_addr(cur, cur->bc_ptrs[level], block);
4726
4727 ldiff = cur->bc_ops->diff_two_keys(cur, hkp, low_key);
4728 hdiff = cur->bc_ops->diff_two_keys(cur, high_key, lkp);
4729
4730 /*
4731 * If (pointer's high key >= query's low key) and
4732 * (query's high key >= pointer's low key), then
4733 * this record overlaps the query range; follow pointer.
4734 */
4735 if (ldiff >= 0 && hdiff >= 0) {
4736 level--;
4737 error = xfs_btree_lookup_get_block(cur, level, pp,
4738 &block);
4739 if (error)
4740 goto out;
4741 xfs_btree_get_block(cur, level, &bp);
4742 trace_xfs_btree_overlapped_query_range(cur, level, bp);
4743#ifdef DEBUG
4744 error = xfs_btree_check_block(cur, block, level, bp);
4745 if (error)
4746 goto out;
4747#endif
4748 cur->bc_ptrs[level] = 1;
4749 continue;
4750 } else if (hdiff < 0) {
4751 /* The low key is larger than the upper range; pop. */
4752 goto pop_up;
4753 }
4754 cur->bc_ptrs[level]++;
4755 }
4756
4757out:
4758 /*
4759 * If we don't end this function with the cursor pointing at a record
4760 * block, a subsequent non-error cursor deletion will not release
4761 * node-level buffers, causing a buffer leak. This is quite possible
4762 * with a zero-results range query, so release the buffers if we
4763 * failed to return any results.
4764 */
4765 if (cur->bc_bufs[0] == NULL) {
4766 for (i = 0; i < cur->bc_nlevels; i++) {
4767 if (cur->bc_bufs[i]) {
4768 xfs_trans_brelse(cur->bc_tp, cur->bc_bufs[i]);
4769 cur->bc_bufs[i] = NULL;
4770 cur->bc_ptrs[i] = 0;
4771 cur->bc_ra[i] = 0;
4772 }
4773 }
4774 }
4775
4776 return error;
4777}
4778
4779/*
4780 * Query a btree for all records overlapping a given interval of keys. The
4781 * supplied function will be called with each record found; return one of the
4782 * XFS_BTREE_QUERY_RANGE_{CONTINUE,ABORT} values or the usual negative error
4783 * code. This function returns XFS_BTREE_QUERY_RANGE_ABORT, zero, or a
4784 * negative error code.
4785 */
4786int
4787xfs_btree_query_range(
4788 struct xfs_btree_cur *cur,
4789 union xfs_btree_irec *low_rec,
4790 union xfs_btree_irec *high_rec,
4791 xfs_btree_query_range_fn fn,
4792 void *priv)
4793{
4794 union xfs_btree_rec rec;
4795 union xfs_btree_key low_key;
4796 union xfs_btree_key high_key;
4797
4798 /* Find the keys of both ends of the interval. */
4799 cur->bc_rec = *high_rec;
4800 cur->bc_ops->init_rec_from_cur(cur, &rec);
4801 cur->bc_ops->init_key_from_rec(&high_key, &rec);
4802
4803 cur->bc_rec = *low_rec;
4804 cur->bc_ops->init_rec_from_cur(cur, &rec);
4805 cur->bc_ops->init_key_from_rec(&low_key, &rec);
4806
4807 /* Enforce low key < high key. */
4808 if (cur->bc_ops->diff_two_keys(cur, &low_key, &high_key) > 0)
4809 return -EINVAL;
4810
4811 if (!(cur->bc_flags & XFS_BTREE_OVERLAPPING))
4812 return xfs_btree_simple_query_range(cur, &low_key,
4813 &high_key, fn, priv);
4814 return xfs_btree_overlapped_query_range(cur, &low_key, &high_key,
4815 fn, priv);
4816}
4817
4818/* Query a btree for all records. */
4819int
4820xfs_btree_query_all(
4821 struct xfs_btree_cur *cur,
4822 xfs_btree_query_range_fn fn,
4823 void *priv)
4824{
4825 union xfs_btree_key low_key;
4826 union xfs_btree_key high_key;
4827
4828 memset(&cur->bc_rec, 0, sizeof(cur->bc_rec));
4829 memset(&low_key, 0, sizeof(low_key));
4830 memset(&high_key, 0xFF, sizeof(high_key));
4831
4832 return xfs_btree_simple_query_range(cur, &low_key, &high_key, fn, priv);
4833}
4834
4835/*
4836 * Calculate the number of blocks needed to store a given number of records
4837 * in a short-format (per-AG metadata) btree.
4838 */
4839xfs_extlen_t
4840xfs_btree_calc_size(
4841 uint *limits,
4842 unsigned long long len)
4843{
4844 int level;
4845 int maxrecs;
4846 xfs_extlen_t rval;
4847
4848 maxrecs = limits[0];
4849 for (level = 0, rval = 0; len > 1; level++) {
4850 len += maxrecs - 1;
4851 do_div(len, maxrecs);
4852 maxrecs = limits[1];
4853 rval += len;
4854 }
4855 return rval;
4856}
4857
4858static int
4859xfs_btree_count_blocks_helper(
4860 struct xfs_btree_cur *cur,
4861 int level,
4862 void *data)
4863{
4864 xfs_extlen_t *blocks = data;
4865 (*blocks)++;
4866
4867 return 0;
4868}
4869
4870/* Count the blocks in a btree and return the result in *blocks. */
4871int
4872xfs_btree_count_blocks(
4873 struct xfs_btree_cur *cur,
4874 xfs_extlen_t *blocks)
4875{
4876 *blocks = 0;
4877 return xfs_btree_visit_blocks(cur, xfs_btree_count_blocks_helper,
4878 blocks);
4879}
4880
4881/* Compare two btree pointers. */
4882int64_t
4883xfs_btree_diff_two_ptrs(
4884 struct xfs_btree_cur *cur,
4885 const union xfs_btree_ptr *a,
4886 const union xfs_btree_ptr *b)
4887{
4888 if (cur->bc_flags & XFS_BTREE_LONG_PTRS)
4889 return (int64_t)be64_to_cpu(a->l) - be64_to_cpu(b->l);
4890 return (int64_t)be32_to_cpu(a->s) - be32_to_cpu(b->s);
4891}
4892
4893/* If there's an extent, we're done. */
4894STATIC int
4895xfs_btree_has_record_helper(
4896 struct xfs_btree_cur *cur,
4897 union xfs_btree_rec *rec,
4898 void *priv)
4899{
4900 return XFS_BTREE_QUERY_RANGE_ABORT;
4901}
4902
4903/* Is there a record covering a given range of keys? */
4904int
4905xfs_btree_has_record(
4906 struct xfs_btree_cur *cur,
4907 union xfs_btree_irec *low,
4908 union xfs_btree_irec *high,
4909 bool *exists)
4910{
4911 int error;
4912
4913 error = xfs_btree_query_range(cur, low, high,
4914 &xfs_btree_has_record_helper, NULL);
4915 if (error == XFS_BTREE_QUERY_RANGE_ABORT) {
4916 *exists = true;
4917 return 0;
4918 }
4919 *exists = false;
4920 return error;
4921}
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright (c) 2000-2002,2005 Silicon Graphics, Inc.
4 * All Rights Reserved.
5 */
6#include "xfs.h"
7#include "xfs_fs.h"
8#include "xfs_shared.h"
9#include "xfs_format.h"
10#include "xfs_log_format.h"
11#include "xfs_trans_resv.h"
12#include "xfs_bit.h"
13#include "xfs_mount.h"
14#include "xfs_inode.h"
15#include "xfs_trans.h"
16#include "xfs_buf_item.h"
17#include "xfs_btree.h"
18#include "xfs_errortag.h"
19#include "xfs_error.h"
20#include "xfs_trace.h"
21#include "xfs_alloc.h"
22#include "xfs_log.h"
23#include "xfs_btree_staging.h"
24#include "xfs_ag.h"
25#include "xfs_alloc_btree.h"
26#include "xfs_ialloc_btree.h"
27#include "xfs_bmap_btree.h"
28#include "xfs_rmap_btree.h"
29#include "xfs_refcount_btree.h"
30
31/*
32 * Btree magic numbers.
33 */
34static const uint32_t xfs_magics[2][XFS_BTNUM_MAX] = {
35 { XFS_ABTB_MAGIC, XFS_ABTC_MAGIC, 0, XFS_BMAP_MAGIC, XFS_IBT_MAGIC,
36 XFS_FIBT_MAGIC, 0 },
37 { XFS_ABTB_CRC_MAGIC, XFS_ABTC_CRC_MAGIC, XFS_RMAP_CRC_MAGIC,
38 XFS_BMAP_CRC_MAGIC, XFS_IBT_CRC_MAGIC, XFS_FIBT_CRC_MAGIC,
39 XFS_REFC_CRC_MAGIC }
40};
41
42uint32_t
43xfs_btree_magic(
44 int crc,
45 xfs_btnum_t btnum)
46{
47 uint32_t magic = xfs_magics[crc][btnum];
48
49 /* Ensure we asked for crc for crc-only magics. */
50 ASSERT(magic != 0);
51 return magic;
52}
53
54/*
55 * These sibling pointer checks are optimised for null sibling pointers. This
56 * happens a lot, and we don't need to byte swap at runtime if the sibling
57 * pointer is NULL.
58 *
59 * These are explicitly marked at inline because the cost of calling them as
60 * functions instead of inlining them is about 36 bytes extra code per call site
61 * on x86-64. Yes, gcc-11 fails to inline them, and explicit inlining of these
62 * two sibling check functions reduces the compiled code size by over 300
63 * bytes.
64 */
65static inline xfs_failaddr_t
66xfs_btree_check_lblock_siblings(
67 struct xfs_mount *mp,
68 struct xfs_btree_cur *cur,
69 int level,
70 xfs_fsblock_t fsb,
71 __be64 dsibling)
72{
73 xfs_fsblock_t sibling;
74
75 if (dsibling == cpu_to_be64(NULLFSBLOCK))
76 return NULL;
77
78 sibling = be64_to_cpu(dsibling);
79 if (sibling == fsb)
80 return __this_address;
81 if (level >= 0) {
82 if (!xfs_btree_check_lptr(cur, sibling, level + 1))
83 return __this_address;
84 } else {
85 if (!xfs_verify_fsbno(mp, sibling))
86 return __this_address;
87 }
88
89 return NULL;
90}
91
92static inline xfs_failaddr_t
93xfs_btree_check_sblock_siblings(
94 struct xfs_perag *pag,
95 struct xfs_btree_cur *cur,
96 int level,
97 xfs_agblock_t agbno,
98 __be32 dsibling)
99{
100 xfs_agblock_t sibling;
101
102 if (dsibling == cpu_to_be32(NULLAGBLOCK))
103 return NULL;
104
105 sibling = be32_to_cpu(dsibling);
106 if (sibling == agbno)
107 return __this_address;
108 if (level >= 0) {
109 if (!xfs_btree_check_sptr(cur, sibling, level + 1))
110 return __this_address;
111 } else {
112 if (!xfs_verify_agbno(pag, sibling))
113 return __this_address;
114 }
115 return NULL;
116}
117
118/*
119 * Check a long btree block header. Return the address of the failing check,
120 * or NULL if everything is ok.
121 */
122xfs_failaddr_t
123__xfs_btree_check_lblock(
124 struct xfs_btree_cur *cur,
125 struct xfs_btree_block *block,
126 int level,
127 struct xfs_buf *bp)
128{
129 struct xfs_mount *mp = cur->bc_mp;
130 xfs_btnum_t btnum = cur->bc_btnum;
131 int crc = xfs_has_crc(mp);
132 xfs_failaddr_t fa;
133 xfs_fsblock_t fsb = NULLFSBLOCK;
134
135 if (crc) {
136 if (!uuid_equal(&block->bb_u.l.bb_uuid, &mp->m_sb.sb_meta_uuid))
137 return __this_address;
138 if (block->bb_u.l.bb_blkno !=
139 cpu_to_be64(bp ? xfs_buf_daddr(bp) : XFS_BUF_DADDR_NULL))
140 return __this_address;
141 if (block->bb_u.l.bb_pad != cpu_to_be32(0))
142 return __this_address;
143 }
144
145 if (be32_to_cpu(block->bb_magic) != xfs_btree_magic(crc, btnum))
146 return __this_address;
147 if (be16_to_cpu(block->bb_level) != level)
148 return __this_address;
149 if (be16_to_cpu(block->bb_numrecs) >
150 cur->bc_ops->get_maxrecs(cur, level))
151 return __this_address;
152
153 if (bp)
154 fsb = XFS_DADDR_TO_FSB(mp, xfs_buf_daddr(bp));
155
156 fa = xfs_btree_check_lblock_siblings(mp, cur, level, fsb,
157 block->bb_u.l.bb_leftsib);
158 if (!fa)
159 fa = xfs_btree_check_lblock_siblings(mp, cur, level, fsb,
160 block->bb_u.l.bb_rightsib);
161 return fa;
162}
163
164/* Check a long btree block header. */
165static int
166xfs_btree_check_lblock(
167 struct xfs_btree_cur *cur,
168 struct xfs_btree_block *block,
169 int level,
170 struct xfs_buf *bp)
171{
172 struct xfs_mount *mp = cur->bc_mp;
173 xfs_failaddr_t fa;
174
175 fa = __xfs_btree_check_lblock(cur, block, level, bp);
176 if (XFS_IS_CORRUPT(mp, fa != NULL) ||
177 XFS_TEST_ERROR(false, mp, XFS_ERRTAG_BTREE_CHECK_LBLOCK)) {
178 if (bp)
179 trace_xfs_btree_corrupt(bp, _RET_IP_);
180 return -EFSCORRUPTED;
181 }
182 return 0;
183}
184
185/*
186 * Check a short btree block header. Return the address of the failing check,
187 * or NULL if everything is ok.
188 */
189xfs_failaddr_t
190__xfs_btree_check_sblock(
191 struct xfs_btree_cur *cur,
192 struct xfs_btree_block *block,
193 int level,
194 struct xfs_buf *bp)
195{
196 struct xfs_mount *mp = cur->bc_mp;
197 struct xfs_perag *pag = cur->bc_ag.pag;
198 xfs_btnum_t btnum = cur->bc_btnum;
199 int crc = xfs_has_crc(mp);
200 xfs_failaddr_t fa;
201 xfs_agblock_t agbno = NULLAGBLOCK;
202
203 if (crc) {
204 if (!uuid_equal(&block->bb_u.s.bb_uuid, &mp->m_sb.sb_meta_uuid))
205 return __this_address;
206 if (block->bb_u.s.bb_blkno !=
207 cpu_to_be64(bp ? xfs_buf_daddr(bp) : XFS_BUF_DADDR_NULL))
208 return __this_address;
209 }
210
211 if (be32_to_cpu(block->bb_magic) != xfs_btree_magic(crc, btnum))
212 return __this_address;
213 if (be16_to_cpu(block->bb_level) != level)
214 return __this_address;
215 if (be16_to_cpu(block->bb_numrecs) >
216 cur->bc_ops->get_maxrecs(cur, level))
217 return __this_address;
218
219 if (bp)
220 agbno = xfs_daddr_to_agbno(mp, xfs_buf_daddr(bp));
221
222 fa = xfs_btree_check_sblock_siblings(pag, cur, level, agbno,
223 block->bb_u.s.bb_leftsib);
224 if (!fa)
225 fa = xfs_btree_check_sblock_siblings(pag, cur, level, agbno,
226 block->bb_u.s.bb_rightsib);
227 return fa;
228}
229
230/* Check a short btree block header. */
231STATIC int
232xfs_btree_check_sblock(
233 struct xfs_btree_cur *cur,
234 struct xfs_btree_block *block,
235 int level,
236 struct xfs_buf *bp)
237{
238 struct xfs_mount *mp = cur->bc_mp;
239 xfs_failaddr_t fa;
240
241 fa = __xfs_btree_check_sblock(cur, block, level, bp);
242 if (XFS_IS_CORRUPT(mp, fa != NULL) ||
243 XFS_TEST_ERROR(false, mp, XFS_ERRTAG_BTREE_CHECK_SBLOCK)) {
244 if (bp)
245 trace_xfs_btree_corrupt(bp, _RET_IP_);
246 return -EFSCORRUPTED;
247 }
248 return 0;
249}
250
251/*
252 * Debug routine: check that block header is ok.
253 */
254int
255xfs_btree_check_block(
256 struct xfs_btree_cur *cur, /* btree cursor */
257 struct xfs_btree_block *block, /* generic btree block pointer */
258 int level, /* level of the btree block */
259 struct xfs_buf *bp) /* buffer containing block, if any */
260{
261 if (cur->bc_flags & XFS_BTREE_LONG_PTRS)
262 return xfs_btree_check_lblock(cur, block, level, bp);
263 else
264 return xfs_btree_check_sblock(cur, block, level, bp);
265}
266
267/* Check that this long pointer is valid and points within the fs. */
268bool
269xfs_btree_check_lptr(
270 struct xfs_btree_cur *cur,
271 xfs_fsblock_t fsbno,
272 int level)
273{
274 if (level <= 0)
275 return false;
276 return xfs_verify_fsbno(cur->bc_mp, fsbno);
277}
278
279/* Check that this short pointer is valid and points within the AG. */
280bool
281xfs_btree_check_sptr(
282 struct xfs_btree_cur *cur,
283 xfs_agblock_t agbno,
284 int level)
285{
286 if (level <= 0)
287 return false;
288 return xfs_verify_agbno(cur->bc_ag.pag, agbno);
289}
290
291/*
292 * Check that a given (indexed) btree pointer at a certain level of a
293 * btree is valid and doesn't point past where it should.
294 */
295static int
296xfs_btree_check_ptr(
297 struct xfs_btree_cur *cur,
298 const union xfs_btree_ptr *ptr,
299 int index,
300 int level)
301{
302 if (cur->bc_flags & XFS_BTREE_LONG_PTRS) {
303 if (xfs_btree_check_lptr(cur, be64_to_cpu((&ptr->l)[index]),
304 level))
305 return 0;
306 xfs_err(cur->bc_mp,
307"Inode %llu fork %d: Corrupt btree %d pointer at level %d index %d.",
308 cur->bc_ino.ip->i_ino,
309 cur->bc_ino.whichfork, cur->bc_btnum,
310 level, index);
311 } else {
312 if (xfs_btree_check_sptr(cur, be32_to_cpu((&ptr->s)[index]),
313 level))
314 return 0;
315 xfs_err(cur->bc_mp,
316"AG %u: Corrupt btree %d pointer at level %d index %d.",
317 cur->bc_ag.pag->pag_agno, cur->bc_btnum,
318 level, index);
319 }
320
321 return -EFSCORRUPTED;
322}
323
324#ifdef DEBUG
325# define xfs_btree_debug_check_ptr xfs_btree_check_ptr
326#else
327# define xfs_btree_debug_check_ptr(...) (0)
328#endif
329
330/*
331 * Calculate CRC on the whole btree block and stuff it into the
332 * long-form btree header.
333 *
334 * Prior to calculting the CRC, pull the LSN out of the buffer log item and put
335 * it into the buffer so recovery knows what the last modification was that made
336 * it to disk.
337 */
338void
339xfs_btree_lblock_calc_crc(
340 struct xfs_buf *bp)
341{
342 struct xfs_btree_block *block = XFS_BUF_TO_BLOCK(bp);
343 struct xfs_buf_log_item *bip = bp->b_log_item;
344
345 if (!xfs_has_crc(bp->b_mount))
346 return;
347 if (bip)
348 block->bb_u.l.bb_lsn = cpu_to_be64(bip->bli_item.li_lsn);
349 xfs_buf_update_cksum(bp, XFS_BTREE_LBLOCK_CRC_OFF);
350}
351
352bool
353xfs_btree_lblock_verify_crc(
354 struct xfs_buf *bp)
355{
356 struct xfs_btree_block *block = XFS_BUF_TO_BLOCK(bp);
357 struct xfs_mount *mp = bp->b_mount;
358
359 if (xfs_has_crc(mp)) {
360 if (!xfs_log_check_lsn(mp, be64_to_cpu(block->bb_u.l.bb_lsn)))
361 return false;
362 return xfs_buf_verify_cksum(bp, XFS_BTREE_LBLOCK_CRC_OFF);
363 }
364
365 return true;
366}
367
368/*
369 * Calculate CRC on the whole btree block and stuff it into the
370 * short-form btree header.
371 *
372 * Prior to calculting the CRC, pull the LSN out of the buffer log item and put
373 * it into the buffer so recovery knows what the last modification was that made
374 * it to disk.
375 */
376void
377xfs_btree_sblock_calc_crc(
378 struct xfs_buf *bp)
379{
380 struct xfs_btree_block *block = XFS_BUF_TO_BLOCK(bp);
381 struct xfs_buf_log_item *bip = bp->b_log_item;
382
383 if (!xfs_has_crc(bp->b_mount))
384 return;
385 if (bip)
386 block->bb_u.s.bb_lsn = cpu_to_be64(bip->bli_item.li_lsn);
387 xfs_buf_update_cksum(bp, XFS_BTREE_SBLOCK_CRC_OFF);
388}
389
390bool
391xfs_btree_sblock_verify_crc(
392 struct xfs_buf *bp)
393{
394 struct xfs_btree_block *block = XFS_BUF_TO_BLOCK(bp);
395 struct xfs_mount *mp = bp->b_mount;
396
397 if (xfs_has_crc(mp)) {
398 if (!xfs_log_check_lsn(mp, be64_to_cpu(block->bb_u.s.bb_lsn)))
399 return false;
400 return xfs_buf_verify_cksum(bp, XFS_BTREE_SBLOCK_CRC_OFF);
401 }
402
403 return true;
404}
405
406static int
407xfs_btree_free_block(
408 struct xfs_btree_cur *cur,
409 struct xfs_buf *bp)
410{
411 int error;
412
413 error = cur->bc_ops->free_block(cur, bp);
414 if (!error) {
415 xfs_trans_binval(cur->bc_tp, bp);
416 XFS_BTREE_STATS_INC(cur, free);
417 }
418 return error;
419}
420
421/*
422 * Delete the btree cursor.
423 */
424void
425xfs_btree_del_cursor(
426 struct xfs_btree_cur *cur, /* btree cursor */
427 int error) /* del because of error */
428{
429 int i; /* btree level */
430
431 /*
432 * Clear the buffer pointers and release the buffers. If we're doing
433 * this because of an error, inspect all of the entries in the bc_bufs
434 * array for buffers to be unlocked. This is because some of the btree
435 * code works from level n down to 0, and if we get an error along the
436 * way we won't have initialized all the entries down to 0.
437 */
438 for (i = 0; i < cur->bc_nlevels; i++) {
439 if (cur->bc_levels[i].bp)
440 xfs_trans_brelse(cur->bc_tp, cur->bc_levels[i].bp);
441 else if (!error)
442 break;
443 }
444
445 /*
446 * If we are doing a BMBT update, the number of unaccounted blocks
447 * allocated during this cursor life time should be zero. If it's not
448 * zero, then we should be shut down or on our way to shutdown due to
449 * cancelling a dirty transaction on error.
450 */
451 ASSERT(cur->bc_btnum != XFS_BTNUM_BMAP || cur->bc_ino.allocated == 0 ||
452 xfs_is_shutdown(cur->bc_mp) || error != 0);
453 if (unlikely(cur->bc_flags & XFS_BTREE_STAGING))
454 kmem_free(cur->bc_ops);
455 if (!(cur->bc_flags & XFS_BTREE_LONG_PTRS) && cur->bc_ag.pag)
456 xfs_perag_put(cur->bc_ag.pag);
457 kmem_cache_free(cur->bc_cache, cur);
458}
459
460/*
461 * Duplicate the btree cursor.
462 * Allocate a new one, copy the record, re-get the buffers.
463 */
464int /* error */
465xfs_btree_dup_cursor(
466 struct xfs_btree_cur *cur, /* input cursor */
467 struct xfs_btree_cur **ncur) /* output cursor */
468{
469 struct xfs_buf *bp; /* btree block's buffer pointer */
470 int error; /* error return value */
471 int i; /* level number of btree block */
472 xfs_mount_t *mp; /* mount structure for filesystem */
473 struct xfs_btree_cur *new; /* new cursor value */
474 xfs_trans_t *tp; /* transaction pointer, can be NULL */
475
476 tp = cur->bc_tp;
477 mp = cur->bc_mp;
478
479 /*
480 * Allocate a new cursor like the old one.
481 */
482 new = cur->bc_ops->dup_cursor(cur);
483
484 /*
485 * Copy the record currently in the cursor.
486 */
487 new->bc_rec = cur->bc_rec;
488
489 /*
490 * For each level current, re-get the buffer and copy the ptr value.
491 */
492 for (i = 0; i < new->bc_nlevels; i++) {
493 new->bc_levels[i].ptr = cur->bc_levels[i].ptr;
494 new->bc_levels[i].ra = cur->bc_levels[i].ra;
495 bp = cur->bc_levels[i].bp;
496 if (bp) {
497 error = xfs_trans_read_buf(mp, tp, mp->m_ddev_targp,
498 xfs_buf_daddr(bp), mp->m_bsize,
499 0, &bp,
500 cur->bc_ops->buf_ops);
501 if (error) {
502 xfs_btree_del_cursor(new, error);
503 *ncur = NULL;
504 return error;
505 }
506 }
507 new->bc_levels[i].bp = bp;
508 }
509 *ncur = new;
510 return 0;
511}
512
513/*
514 * XFS btree block layout and addressing:
515 *
516 * There are two types of blocks in the btree: leaf and non-leaf blocks.
517 *
518 * The leaf record start with a header then followed by records containing
519 * the values. A non-leaf block also starts with the same header, and
520 * then first contains lookup keys followed by an equal number of pointers
521 * to the btree blocks at the previous level.
522 *
523 * +--------+-------+-------+-------+-------+-------+-------+
524 * Leaf: | header | rec 1 | rec 2 | rec 3 | rec 4 | rec 5 | rec N |
525 * +--------+-------+-------+-------+-------+-------+-------+
526 *
527 * +--------+-------+-------+-------+-------+-------+-------+
528 * Non-Leaf: | header | key 1 | key 2 | key N | ptr 1 | ptr 2 | ptr N |
529 * +--------+-------+-------+-------+-------+-------+-------+
530 *
531 * The header is called struct xfs_btree_block for reasons better left unknown
532 * and comes in different versions for short (32bit) and long (64bit) block
533 * pointers. The record and key structures are defined by the btree instances
534 * and opaque to the btree core. The block pointers are simple disk endian
535 * integers, available in a short (32bit) and long (64bit) variant.
536 *
537 * The helpers below calculate the offset of a given record, key or pointer
538 * into a btree block (xfs_btree_*_offset) or return a pointer to the given
539 * record, key or pointer (xfs_btree_*_addr). Note that all addressing
540 * inside the btree block is done using indices starting at one, not zero!
541 *
542 * If XFS_BTREE_OVERLAPPING is set, then this btree supports keys containing
543 * overlapping intervals. In such a tree, records are still sorted lowest to
544 * highest and indexed by the smallest key value that refers to the record.
545 * However, nodes are different: each pointer has two associated keys -- one
546 * indexing the lowest key available in the block(s) below (the same behavior
547 * as the key in a regular btree) and another indexing the highest key
548 * available in the block(s) below. Because records are /not/ sorted by the
549 * highest key, all leaf block updates require us to compute the highest key
550 * that matches any record in the leaf and to recursively update the high keys
551 * in the nodes going further up in the tree, if necessary. Nodes look like
552 * this:
553 *
554 * +--------+-----+-----+-----+-----+-----+-------+-------+-----+
555 * Non-Leaf: | header | lo1 | hi1 | lo2 | hi2 | ... | ptr 1 | ptr 2 | ... |
556 * +--------+-----+-----+-----+-----+-----+-------+-------+-----+
557 *
558 * To perform an interval query on an overlapped tree, perform the usual
559 * depth-first search and use the low and high keys to decide if we can skip
560 * that particular node. If a leaf node is reached, return the records that
561 * intersect the interval. Note that an interval query may return numerous
562 * entries. For a non-overlapped tree, simply search for the record associated
563 * with the lowest key and iterate forward until a non-matching record is
564 * found. Section 14.3 ("Interval Trees") of _Introduction to Algorithms_ by
565 * Cormen, Leiserson, Rivest, and Stein (2nd or 3rd ed. only) discuss this in
566 * more detail.
567 *
568 * Why do we care about overlapping intervals? Let's say you have a bunch of
569 * reverse mapping records on a reflink filesystem:
570 *
571 * 1: +- file A startblock B offset C length D -----------+
572 * 2: +- file E startblock F offset G length H --------------+
573 * 3: +- file I startblock F offset J length K --+
574 * 4: +- file L... --+
575 *
576 * Now say we want to map block (B+D) into file A at offset (C+D). Ideally,
577 * we'd simply increment the length of record 1. But how do we find the record
578 * that ends at (B+D-1) (i.e. record 1)? A LE lookup of (B+D-1) would return
579 * record 3 because the keys are ordered first by startblock. An interval
580 * query would return records 1 and 2 because they both overlap (B+D-1), and
581 * from that we can pick out record 1 as the appropriate left neighbor.
582 *
583 * In the non-overlapped case you can do a LE lookup and decrement the cursor
584 * because a record's interval must end before the next record.
585 */
586
587/*
588 * Return size of the btree block header for this btree instance.
589 */
590static inline size_t xfs_btree_block_len(struct xfs_btree_cur *cur)
591{
592 if (cur->bc_flags & XFS_BTREE_LONG_PTRS) {
593 if (cur->bc_flags & XFS_BTREE_CRC_BLOCKS)
594 return XFS_BTREE_LBLOCK_CRC_LEN;
595 return XFS_BTREE_LBLOCK_LEN;
596 }
597 if (cur->bc_flags & XFS_BTREE_CRC_BLOCKS)
598 return XFS_BTREE_SBLOCK_CRC_LEN;
599 return XFS_BTREE_SBLOCK_LEN;
600}
601
602/*
603 * Return size of btree block pointers for this btree instance.
604 */
605static inline size_t xfs_btree_ptr_len(struct xfs_btree_cur *cur)
606{
607 return (cur->bc_flags & XFS_BTREE_LONG_PTRS) ?
608 sizeof(__be64) : sizeof(__be32);
609}
610
611/*
612 * Calculate offset of the n-th record in a btree block.
613 */
614STATIC size_t
615xfs_btree_rec_offset(
616 struct xfs_btree_cur *cur,
617 int n)
618{
619 return xfs_btree_block_len(cur) +
620 (n - 1) * cur->bc_ops->rec_len;
621}
622
623/*
624 * Calculate offset of the n-th key in a btree block.
625 */
626STATIC size_t
627xfs_btree_key_offset(
628 struct xfs_btree_cur *cur,
629 int n)
630{
631 return xfs_btree_block_len(cur) +
632 (n - 1) * cur->bc_ops->key_len;
633}
634
635/*
636 * Calculate offset of the n-th high key in a btree block.
637 */
638STATIC size_t
639xfs_btree_high_key_offset(
640 struct xfs_btree_cur *cur,
641 int n)
642{
643 return xfs_btree_block_len(cur) +
644 (n - 1) * cur->bc_ops->key_len + (cur->bc_ops->key_len / 2);
645}
646
647/*
648 * Calculate offset of the n-th block pointer in a btree block.
649 */
650STATIC size_t
651xfs_btree_ptr_offset(
652 struct xfs_btree_cur *cur,
653 int n,
654 int level)
655{
656 return xfs_btree_block_len(cur) +
657 cur->bc_ops->get_maxrecs(cur, level) * cur->bc_ops->key_len +
658 (n - 1) * xfs_btree_ptr_len(cur);
659}
660
661/*
662 * Return a pointer to the n-th record in the btree block.
663 */
664union xfs_btree_rec *
665xfs_btree_rec_addr(
666 struct xfs_btree_cur *cur,
667 int n,
668 struct xfs_btree_block *block)
669{
670 return (union xfs_btree_rec *)
671 ((char *)block + xfs_btree_rec_offset(cur, n));
672}
673
674/*
675 * Return a pointer to the n-th key in the btree block.
676 */
677union xfs_btree_key *
678xfs_btree_key_addr(
679 struct xfs_btree_cur *cur,
680 int n,
681 struct xfs_btree_block *block)
682{
683 return (union xfs_btree_key *)
684 ((char *)block + xfs_btree_key_offset(cur, n));
685}
686
687/*
688 * Return a pointer to the n-th high key in the btree block.
689 */
690union xfs_btree_key *
691xfs_btree_high_key_addr(
692 struct xfs_btree_cur *cur,
693 int n,
694 struct xfs_btree_block *block)
695{
696 return (union xfs_btree_key *)
697 ((char *)block + xfs_btree_high_key_offset(cur, n));
698}
699
700/*
701 * Return a pointer to the n-th block pointer in the btree block.
702 */
703union xfs_btree_ptr *
704xfs_btree_ptr_addr(
705 struct xfs_btree_cur *cur,
706 int n,
707 struct xfs_btree_block *block)
708{
709 int level = xfs_btree_get_level(block);
710
711 ASSERT(block->bb_level != 0);
712
713 return (union xfs_btree_ptr *)
714 ((char *)block + xfs_btree_ptr_offset(cur, n, level));
715}
716
717struct xfs_ifork *
718xfs_btree_ifork_ptr(
719 struct xfs_btree_cur *cur)
720{
721 ASSERT(cur->bc_flags & XFS_BTREE_ROOT_IN_INODE);
722
723 if (cur->bc_flags & XFS_BTREE_STAGING)
724 return cur->bc_ino.ifake->if_fork;
725 return xfs_ifork_ptr(cur->bc_ino.ip, cur->bc_ino.whichfork);
726}
727
728/*
729 * Get the root block which is stored in the inode.
730 *
731 * For now this btree implementation assumes the btree root is always
732 * stored in the if_broot field of an inode fork.
733 */
734STATIC struct xfs_btree_block *
735xfs_btree_get_iroot(
736 struct xfs_btree_cur *cur)
737{
738 struct xfs_ifork *ifp = xfs_btree_ifork_ptr(cur);
739
740 return (struct xfs_btree_block *)ifp->if_broot;
741}
742
743/*
744 * Retrieve the block pointer from the cursor at the given level.
745 * This may be an inode btree root or from a buffer.
746 */
747struct xfs_btree_block * /* generic btree block pointer */
748xfs_btree_get_block(
749 struct xfs_btree_cur *cur, /* btree cursor */
750 int level, /* level in btree */
751 struct xfs_buf **bpp) /* buffer containing the block */
752{
753 if ((cur->bc_flags & XFS_BTREE_ROOT_IN_INODE) &&
754 (level == cur->bc_nlevels - 1)) {
755 *bpp = NULL;
756 return xfs_btree_get_iroot(cur);
757 }
758
759 *bpp = cur->bc_levels[level].bp;
760 return XFS_BUF_TO_BLOCK(*bpp);
761}
762
763/*
764 * Change the cursor to point to the first record at the given level.
765 * Other levels are unaffected.
766 */
767STATIC int /* success=1, failure=0 */
768xfs_btree_firstrec(
769 struct xfs_btree_cur *cur, /* btree cursor */
770 int level) /* level to change */
771{
772 struct xfs_btree_block *block; /* generic btree block pointer */
773 struct xfs_buf *bp; /* buffer containing block */
774
775 /*
776 * Get the block pointer for this level.
777 */
778 block = xfs_btree_get_block(cur, level, &bp);
779 if (xfs_btree_check_block(cur, block, level, bp))
780 return 0;
781 /*
782 * It's empty, there is no such record.
783 */
784 if (!block->bb_numrecs)
785 return 0;
786 /*
787 * Set the ptr value to 1, that's the first record/key.
788 */
789 cur->bc_levels[level].ptr = 1;
790 return 1;
791}
792
793/*
794 * Change the cursor to point to the last record in the current block
795 * at the given level. Other levels are unaffected.
796 */
797STATIC int /* success=1, failure=0 */
798xfs_btree_lastrec(
799 struct xfs_btree_cur *cur, /* btree cursor */
800 int level) /* level to change */
801{
802 struct xfs_btree_block *block; /* generic btree block pointer */
803 struct xfs_buf *bp; /* buffer containing block */
804
805 /*
806 * Get the block pointer for this level.
807 */
808 block = xfs_btree_get_block(cur, level, &bp);
809 if (xfs_btree_check_block(cur, block, level, bp))
810 return 0;
811 /*
812 * It's empty, there is no such record.
813 */
814 if (!block->bb_numrecs)
815 return 0;
816 /*
817 * Set the ptr value to numrecs, that's the last record/key.
818 */
819 cur->bc_levels[level].ptr = be16_to_cpu(block->bb_numrecs);
820 return 1;
821}
822
823/*
824 * Compute first and last byte offsets for the fields given.
825 * Interprets the offsets table, which contains struct field offsets.
826 */
827void
828xfs_btree_offsets(
829 uint32_t fields, /* bitmask of fields */
830 const short *offsets, /* table of field offsets */
831 int nbits, /* number of bits to inspect */
832 int *first, /* output: first byte offset */
833 int *last) /* output: last byte offset */
834{
835 int i; /* current bit number */
836 uint32_t imask; /* mask for current bit number */
837
838 ASSERT(fields != 0);
839 /*
840 * Find the lowest bit, so the first byte offset.
841 */
842 for (i = 0, imask = 1u; ; i++, imask <<= 1) {
843 if (imask & fields) {
844 *first = offsets[i];
845 break;
846 }
847 }
848 /*
849 * Find the highest bit, so the last byte offset.
850 */
851 for (i = nbits - 1, imask = 1u << i; ; i--, imask >>= 1) {
852 if (imask & fields) {
853 *last = offsets[i + 1] - 1;
854 break;
855 }
856 }
857}
858
859/*
860 * Get a buffer for the block, return it read in.
861 * Long-form addressing.
862 */
863int
864xfs_btree_read_bufl(
865 struct xfs_mount *mp, /* file system mount point */
866 struct xfs_trans *tp, /* transaction pointer */
867 xfs_fsblock_t fsbno, /* file system block number */
868 struct xfs_buf **bpp, /* buffer for fsbno */
869 int refval, /* ref count value for buffer */
870 const struct xfs_buf_ops *ops)
871{
872 struct xfs_buf *bp; /* return value */
873 xfs_daddr_t d; /* real disk block address */
874 int error;
875
876 if (!xfs_verify_fsbno(mp, fsbno))
877 return -EFSCORRUPTED;
878 d = XFS_FSB_TO_DADDR(mp, fsbno);
879 error = xfs_trans_read_buf(mp, tp, mp->m_ddev_targp, d,
880 mp->m_bsize, 0, &bp, ops);
881 if (error)
882 return error;
883 if (bp)
884 xfs_buf_set_ref(bp, refval);
885 *bpp = bp;
886 return 0;
887}
888
889/*
890 * Read-ahead the block, don't wait for it, don't return a buffer.
891 * Long-form addressing.
892 */
893/* ARGSUSED */
894void
895xfs_btree_reada_bufl(
896 struct xfs_mount *mp, /* file system mount point */
897 xfs_fsblock_t fsbno, /* file system block number */
898 xfs_extlen_t count, /* count of filesystem blocks */
899 const struct xfs_buf_ops *ops)
900{
901 xfs_daddr_t d;
902
903 ASSERT(fsbno != NULLFSBLOCK);
904 d = XFS_FSB_TO_DADDR(mp, fsbno);
905 xfs_buf_readahead(mp->m_ddev_targp, d, mp->m_bsize * count, ops);
906}
907
908/*
909 * Read-ahead the block, don't wait for it, don't return a buffer.
910 * Short-form addressing.
911 */
912/* ARGSUSED */
913void
914xfs_btree_reada_bufs(
915 struct xfs_mount *mp, /* file system mount point */
916 xfs_agnumber_t agno, /* allocation group number */
917 xfs_agblock_t agbno, /* allocation group block number */
918 xfs_extlen_t count, /* count of filesystem blocks */
919 const struct xfs_buf_ops *ops)
920{
921 xfs_daddr_t d;
922
923 ASSERT(agno != NULLAGNUMBER);
924 ASSERT(agbno != NULLAGBLOCK);
925 d = XFS_AGB_TO_DADDR(mp, agno, agbno);
926 xfs_buf_readahead(mp->m_ddev_targp, d, mp->m_bsize * count, ops);
927}
928
929STATIC int
930xfs_btree_readahead_lblock(
931 struct xfs_btree_cur *cur,
932 int lr,
933 struct xfs_btree_block *block)
934{
935 int rval = 0;
936 xfs_fsblock_t left = be64_to_cpu(block->bb_u.l.bb_leftsib);
937 xfs_fsblock_t right = be64_to_cpu(block->bb_u.l.bb_rightsib);
938
939 if ((lr & XFS_BTCUR_LEFTRA) && left != NULLFSBLOCK) {
940 xfs_btree_reada_bufl(cur->bc_mp, left, 1,
941 cur->bc_ops->buf_ops);
942 rval++;
943 }
944
945 if ((lr & XFS_BTCUR_RIGHTRA) && right != NULLFSBLOCK) {
946 xfs_btree_reada_bufl(cur->bc_mp, right, 1,
947 cur->bc_ops->buf_ops);
948 rval++;
949 }
950
951 return rval;
952}
953
954STATIC int
955xfs_btree_readahead_sblock(
956 struct xfs_btree_cur *cur,
957 int lr,
958 struct xfs_btree_block *block)
959{
960 int rval = 0;
961 xfs_agblock_t left = be32_to_cpu(block->bb_u.s.bb_leftsib);
962 xfs_agblock_t right = be32_to_cpu(block->bb_u.s.bb_rightsib);
963
964
965 if ((lr & XFS_BTCUR_LEFTRA) && left != NULLAGBLOCK) {
966 xfs_btree_reada_bufs(cur->bc_mp, cur->bc_ag.pag->pag_agno,
967 left, 1, cur->bc_ops->buf_ops);
968 rval++;
969 }
970
971 if ((lr & XFS_BTCUR_RIGHTRA) && right != NULLAGBLOCK) {
972 xfs_btree_reada_bufs(cur->bc_mp, cur->bc_ag.pag->pag_agno,
973 right, 1, cur->bc_ops->buf_ops);
974 rval++;
975 }
976
977 return rval;
978}
979
980/*
981 * Read-ahead btree blocks, at the given level.
982 * Bits in lr are set from XFS_BTCUR_{LEFT,RIGHT}RA.
983 */
984STATIC int
985xfs_btree_readahead(
986 struct xfs_btree_cur *cur, /* btree cursor */
987 int lev, /* level in btree */
988 int lr) /* left/right bits */
989{
990 struct xfs_btree_block *block;
991
992 /*
993 * No readahead needed if we are at the root level and the
994 * btree root is stored in the inode.
995 */
996 if ((cur->bc_flags & XFS_BTREE_ROOT_IN_INODE) &&
997 (lev == cur->bc_nlevels - 1))
998 return 0;
999
1000 if ((cur->bc_levels[lev].ra | lr) == cur->bc_levels[lev].ra)
1001 return 0;
1002
1003 cur->bc_levels[lev].ra |= lr;
1004 block = XFS_BUF_TO_BLOCK(cur->bc_levels[lev].bp);
1005
1006 if (cur->bc_flags & XFS_BTREE_LONG_PTRS)
1007 return xfs_btree_readahead_lblock(cur, lr, block);
1008 return xfs_btree_readahead_sblock(cur, lr, block);
1009}
1010
1011STATIC int
1012xfs_btree_ptr_to_daddr(
1013 struct xfs_btree_cur *cur,
1014 const union xfs_btree_ptr *ptr,
1015 xfs_daddr_t *daddr)
1016{
1017 xfs_fsblock_t fsbno;
1018 xfs_agblock_t agbno;
1019 int error;
1020
1021 error = xfs_btree_check_ptr(cur, ptr, 0, 1);
1022 if (error)
1023 return error;
1024
1025 if (cur->bc_flags & XFS_BTREE_LONG_PTRS) {
1026 fsbno = be64_to_cpu(ptr->l);
1027 *daddr = XFS_FSB_TO_DADDR(cur->bc_mp, fsbno);
1028 } else {
1029 agbno = be32_to_cpu(ptr->s);
1030 *daddr = XFS_AGB_TO_DADDR(cur->bc_mp, cur->bc_ag.pag->pag_agno,
1031 agbno);
1032 }
1033
1034 return 0;
1035}
1036
1037/*
1038 * Readahead @count btree blocks at the given @ptr location.
1039 *
1040 * We don't need to care about long or short form btrees here as we have a
1041 * method of converting the ptr directly to a daddr available to us.
1042 */
1043STATIC void
1044xfs_btree_readahead_ptr(
1045 struct xfs_btree_cur *cur,
1046 union xfs_btree_ptr *ptr,
1047 xfs_extlen_t count)
1048{
1049 xfs_daddr_t daddr;
1050
1051 if (xfs_btree_ptr_to_daddr(cur, ptr, &daddr))
1052 return;
1053 xfs_buf_readahead(cur->bc_mp->m_ddev_targp, daddr,
1054 cur->bc_mp->m_bsize * count, cur->bc_ops->buf_ops);
1055}
1056
1057/*
1058 * Set the buffer for level "lev" in the cursor to bp, releasing
1059 * any previous buffer.
1060 */
1061STATIC void
1062xfs_btree_setbuf(
1063 struct xfs_btree_cur *cur, /* btree cursor */
1064 int lev, /* level in btree */
1065 struct xfs_buf *bp) /* new buffer to set */
1066{
1067 struct xfs_btree_block *b; /* btree block */
1068
1069 if (cur->bc_levels[lev].bp)
1070 xfs_trans_brelse(cur->bc_tp, cur->bc_levels[lev].bp);
1071 cur->bc_levels[lev].bp = bp;
1072 cur->bc_levels[lev].ra = 0;
1073
1074 b = XFS_BUF_TO_BLOCK(bp);
1075 if (cur->bc_flags & XFS_BTREE_LONG_PTRS) {
1076 if (b->bb_u.l.bb_leftsib == cpu_to_be64(NULLFSBLOCK))
1077 cur->bc_levels[lev].ra |= XFS_BTCUR_LEFTRA;
1078 if (b->bb_u.l.bb_rightsib == cpu_to_be64(NULLFSBLOCK))
1079 cur->bc_levels[lev].ra |= XFS_BTCUR_RIGHTRA;
1080 } else {
1081 if (b->bb_u.s.bb_leftsib == cpu_to_be32(NULLAGBLOCK))
1082 cur->bc_levels[lev].ra |= XFS_BTCUR_LEFTRA;
1083 if (b->bb_u.s.bb_rightsib == cpu_to_be32(NULLAGBLOCK))
1084 cur->bc_levels[lev].ra |= XFS_BTCUR_RIGHTRA;
1085 }
1086}
1087
1088bool
1089xfs_btree_ptr_is_null(
1090 struct xfs_btree_cur *cur,
1091 const union xfs_btree_ptr *ptr)
1092{
1093 if (cur->bc_flags & XFS_BTREE_LONG_PTRS)
1094 return ptr->l == cpu_to_be64(NULLFSBLOCK);
1095 else
1096 return ptr->s == cpu_to_be32(NULLAGBLOCK);
1097}
1098
1099void
1100xfs_btree_set_ptr_null(
1101 struct xfs_btree_cur *cur,
1102 union xfs_btree_ptr *ptr)
1103{
1104 if (cur->bc_flags & XFS_BTREE_LONG_PTRS)
1105 ptr->l = cpu_to_be64(NULLFSBLOCK);
1106 else
1107 ptr->s = cpu_to_be32(NULLAGBLOCK);
1108}
1109
1110/*
1111 * Get/set/init sibling pointers
1112 */
1113void
1114xfs_btree_get_sibling(
1115 struct xfs_btree_cur *cur,
1116 struct xfs_btree_block *block,
1117 union xfs_btree_ptr *ptr,
1118 int lr)
1119{
1120 ASSERT(lr == XFS_BB_LEFTSIB || lr == XFS_BB_RIGHTSIB);
1121
1122 if (cur->bc_flags & XFS_BTREE_LONG_PTRS) {
1123 if (lr == XFS_BB_RIGHTSIB)
1124 ptr->l = block->bb_u.l.bb_rightsib;
1125 else
1126 ptr->l = block->bb_u.l.bb_leftsib;
1127 } else {
1128 if (lr == XFS_BB_RIGHTSIB)
1129 ptr->s = block->bb_u.s.bb_rightsib;
1130 else
1131 ptr->s = block->bb_u.s.bb_leftsib;
1132 }
1133}
1134
1135void
1136xfs_btree_set_sibling(
1137 struct xfs_btree_cur *cur,
1138 struct xfs_btree_block *block,
1139 const union xfs_btree_ptr *ptr,
1140 int lr)
1141{
1142 ASSERT(lr == XFS_BB_LEFTSIB || lr == XFS_BB_RIGHTSIB);
1143
1144 if (cur->bc_flags & XFS_BTREE_LONG_PTRS) {
1145 if (lr == XFS_BB_RIGHTSIB)
1146 block->bb_u.l.bb_rightsib = ptr->l;
1147 else
1148 block->bb_u.l.bb_leftsib = ptr->l;
1149 } else {
1150 if (lr == XFS_BB_RIGHTSIB)
1151 block->bb_u.s.bb_rightsib = ptr->s;
1152 else
1153 block->bb_u.s.bb_leftsib = ptr->s;
1154 }
1155}
1156
1157void
1158xfs_btree_init_block_int(
1159 struct xfs_mount *mp,
1160 struct xfs_btree_block *buf,
1161 xfs_daddr_t blkno,
1162 xfs_btnum_t btnum,
1163 __u16 level,
1164 __u16 numrecs,
1165 __u64 owner,
1166 unsigned int flags)
1167{
1168 int crc = xfs_has_crc(mp);
1169 __u32 magic = xfs_btree_magic(crc, btnum);
1170
1171 buf->bb_magic = cpu_to_be32(magic);
1172 buf->bb_level = cpu_to_be16(level);
1173 buf->bb_numrecs = cpu_to_be16(numrecs);
1174
1175 if (flags & XFS_BTREE_LONG_PTRS) {
1176 buf->bb_u.l.bb_leftsib = cpu_to_be64(NULLFSBLOCK);
1177 buf->bb_u.l.bb_rightsib = cpu_to_be64(NULLFSBLOCK);
1178 if (crc) {
1179 buf->bb_u.l.bb_blkno = cpu_to_be64(blkno);
1180 buf->bb_u.l.bb_owner = cpu_to_be64(owner);
1181 uuid_copy(&buf->bb_u.l.bb_uuid, &mp->m_sb.sb_meta_uuid);
1182 buf->bb_u.l.bb_pad = 0;
1183 buf->bb_u.l.bb_lsn = 0;
1184 }
1185 } else {
1186 /* owner is a 32 bit value on short blocks */
1187 __u32 __owner = (__u32)owner;
1188
1189 buf->bb_u.s.bb_leftsib = cpu_to_be32(NULLAGBLOCK);
1190 buf->bb_u.s.bb_rightsib = cpu_to_be32(NULLAGBLOCK);
1191 if (crc) {
1192 buf->bb_u.s.bb_blkno = cpu_to_be64(blkno);
1193 buf->bb_u.s.bb_owner = cpu_to_be32(__owner);
1194 uuid_copy(&buf->bb_u.s.bb_uuid, &mp->m_sb.sb_meta_uuid);
1195 buf->bb_u.s.bb_lsn = 0;
1196 }
1197 }
1198}
1199
1200void
1201xfs_btree_init_block(
1202 struct xfs_mount *mp,
1203 struct xfs_buf *bp,
1204 xfs_btnum_t btnum,
1205 __u16 level,
1206 __u16 numrecs,
1207 __u64 owner)
1208{
1209 xfs_btree_init_block_int(mp, XFS_BUF_TO_BLOCK(bp), xfs_buf_daddr(bp),
1210 btnum, level, numrecs, owner, 0);
1211}
1212
1213void
1214xfs_btree_init_block_cur(
1215 struct xfs_btree_cur *cur,
1216 struct xfs_buf *bp,
1217 int level,
1218 int numrecs)
1219{
1220 __u64 owner;
1221
1222 /*
1223 * we can pull the owner from the cursor right now as the different
1224 * owners align directly with the pointer size of the btree. This may
1225 * change in future, but is safe for current users of the generic btree
1226 * code.
1227 */
1228 if (cur->bc_flags & XFS_BTREE_LONG_PTRS)
1229 owner = cur->bc_ino.ip->i_ino;
1230 else
1231 owner = cur->bc_ag.pag->pag_agno;
1232
1233 xfs_btree_init_block_int(cur->bc_mp, XFS_BUF_TO_BLOCK(bp),
1234 xfs_buf_daddr(bp), cur->bc_btnum, level,
1235 numrecs, owner, cur->bc_flags);
1236}
1237
1238/*
1239 * Return true if ptr is the last record in the btree and
1240 * we need to track updates to this record. The decision
1241 * will be further refined in the update_lastrec method.
1242 */
1243STATIC int
1244xfs_btree_is_lastrec(
1245 struct xfs_btree_cur *cur,
1246 struct xfs_btree_block *block,
1247 int level)
1248{
1249 union xfs_btree_ptr ptr;
1250
1251 if (level > 0)
1252 return 0;
1253 if (!(cur->bc_flags & XFS_BTREE_LASTREC_UPDATE))
1254 return 0;
1255
1256 xfs_btree_get_sibling(cur, block, &ptr, XFS_BB_RIGHTSIB);
1257 if (!xfs_btree_ptr_is_null(cur, &ptr))
1258 return 0;
1259 return 1;
1260}
1261
1262STATIC void
1263xfs_btree_buf_to_ptr(
1264 struct xfs_btree_cur *cur,
1265 struct xfs_buf *bp,
1266 union xfs_btree_ptr *ptr)
1267{
1268 if (cur->bc_flags & XFS_BTREE_LONG_PTRS)
1269 ptr->l = cpu_to_be64(XFS_DADDR_TO_FSB(cur->bc_mp,
1270 xfs_buf_daddr(bp)));
1271 else {
1272 ptr->s = cpu_to_be32(xfs_daddr_to_agbno(cur->bc_mp,
1273 xfs_buf_daddr(bp)));
1274 }
1275}
1276
1277STATIC void
1278xfs_btree_set_refs(
1279 struct xfs_btree_cur *cur,
1280 struct xfs_buf *bp)
1281{
1282 switch (cur->bc_btnum) {
1283 case XFS_BTNUM_BNO:
1284 case XFS_BTNUM_CNT:
1285 xfs_buf_set_ref(bp, XFS_ALLOC_BTREE_REF);
1286 break;
1287 case XFS_BTNUM_INO:
1288 case XFS_BTNUM_FINO:
1289 xfs_buf_set_ref(bp, XFS_INO_BTREE_REF);
1290 break;
1291 case XFS_BTNUM_BMAP:
1292 xfs_buf_set_ref(bp, XFS_BMAP_BTREE_REF);
1293 break;
1294 case XFS_BTNUM_RMAP:
1295 xfs_buf_set_ref(bp, XFS_RMAP_BTREE_REF);
1296 break;
1297 case XFS_BTNUM_REFC:
1298 xfs_buf_set_ref(bp, XFS_REFC_BTREE_REF);
1299 break;
1300 default:
1301 ASSERT(0);
1302 }
1303}
1304
1305int
1306xfs_btree_get_buf_block(
1307 struct xfs_btree_cur *cur,
1308 const union xfs_btree_ptr *ptr,
1309 struct xfs_btree_block **block,
1310 struct xfs_buf **bpp)
1311{
1312 struct xfs_mount *mp = cur->bc_mp;
1313 xfs_daddr_t d;
1314 int error;
1315
1316 error = xfs_btree_ptr_to_daddr(cur, ptr, &d);
1317 if (error)
1318 return error;
1319 error = xfs_trans_get_buf(cur->bc_tp, mp->m_ddev_targp, d, mp->m_bsize,
1320 0, bpp);
1321 if (error)
1322 return error;
1323
1324 (*bpp)->b_ops = cur->bc_ops->buf_ops;
1325 *block = XFS_BUF_TO_BLOCK(*bpp);
1326 return 0;
1327}
1328
1329/*
1330 * Read in the buffer at the given ptr and return the buffer and
1331 * the block pointer within the buffer.
1332 */
1333int
1334xfs_btree_read_buf_block(
1335 struct xfs_btree_cur *cur,
1336 const union xfs_btree_ptr *ptr,
1337 int flags,
1338 struct xfs_btree_block **block,
1339 struct xfs_buf **bpp)
1340{
1341 struct xfs_mount *mp = cur->bc_mp;
1342 xfs_daddr_t d;
1343 int error;
1344
1345 /* need to sort out how callers deal with failures first */
1346 ASSERT(!(flags & XBF_TRYLOCK));
1347
1348 error = xfs_btree_ptr_to_daddr(cur, ptr, &d);
1349 if (error)
1350 return error;
1351 error = xfs_trans_read_buf(mp, cur->bc_tp, mp->m_ddev_targp, d,
1352 mp->m_bsize, flags, bpp,
1353 cur->bc_ops->buf_ops);
1354 if (error)
1355 return error;
1356
1357 xfs_btree_set_refs(cur, *bpp);
1358 *block = XFS_BUF_TO_BLOCK(*bpp);
1359 return 0;
1360}
1361
1362/*
1363 * Copy keys from one btree block to another.
1364 */
1365void
1366xfs_btree_copy_keys(
1367 struct xfs_btree_cur *cur,
1368 union xfs_btree_key *dst_key,
1369 const union xfs_btree_key *src_key,
1370 int numkeys)
1371{
1372 ASSERT(numkeys >= 0);
1373 memcpy(dst_key, src_key, numkeys * cur->bc_ops->key_len);
1374}
1375
1376/*
1377 * Copy records from one btree block to another.
1378 */
1379STATIC void
1380xfs_btree_copy_recs(
1381 struct xfs_btree_cur *cur,
1382 union xfs_btree_rec *dst_rec,
1383 union xfs_btree_rec *src_rec,
1384 int numrecs)
1385{
1386 ASSERT(numrecs >= 0);
1387 memcpy(dst_rec, src_rec, numrecs * cur->bc_ops->rec_len);
1388}
1389
1390/*
1391 * Copy block pointers from one btree block to another.
1392 */
1393void
1394xfs_btree_copy_ptrs(
1395 struct xfs_btree_cur *cur,
1396 union xfs_btree_ptr *dst_ptr,
1397 const union xfs_btree_ptr *src_ptr,
1398 int numptrs)
1399{
1400 ASSERT(numptrs >= 0);
1401 memcpy(dst_ptr, src_ptr, numptrs * xfs_btree_ptr_len(cur));
1402}
1403
1404/*
1405 * Shift keys one index left/right inside a single btree block.
1406 */
1407STATIC void
1408xfs_btree_shift_keys(
1409 struct xfs_btree_cur *cur,
1410 union xfs_btree_key *key,
1411 int dir,
1412 int numkeys)
1413{
1414 char *dst_key;
1415
1416 ASSERT(numkeys >= 0);
1417 ASSERT(dir == 1 || dir == -1);
1418
1419 dst_key = (char *)key + (dir * cur->bc_ops->key_len);
1420 memmove(dst_key, key, numkeys * cur->bc_ops->key_len);
1421}
1422
1423/*
1424 * Shift records one index left/right inside a single btree block.
1425 */
1426STATIC void
1427xfs_btree_shift_recs(
1428 struct xfs_btree_cur *cur,
1429 union xfs_btree_rec *rec,
1430 int dir,
1431 int numrecs)
1432{
1433 char *dst_rec;
1434
1435 ASSERT(numrecs >= 0);
1436 ASSERT(dir == 1 || dir == -1);
1437
1438 dst_rec = (char *)rec + (dir * cur->bc_ops->rec_len);
1439 memmove(dst_rec, rec, numrecs * cur->bc_ops->rec_len);
1440}
1441
1442/*
1443 * Shift block pointers one index left/right inside a single btree block.
1444 */
1445STATIC void
1446xfs_btree_shift_ptrs(
1447 struct xfs_btree_cur *cur,
1448 union xfs_btree_ptr *ptr,
1449 int dir,
1450 int numptrs)
1451{
1452 char *dst_ptr;
1453
1454 ASSERT(numptrs >= 0);
1455 ASSERT(dir == 1 || dir == -1);
1456
1457 dst_ptr = (char *)ptr + (dir * xfs_btree_ptr_len(cur));
1458 memmove(dst_ptr, ptr, numptrs * xfs_btree_ptr_len(cur));
1459}
1460
1461/*
1462 * Log key values from the btree block.
1463 */
1464STATIC void
1465xfs_btree_log_keys(
1466 struct xfs_btree_cur *cur,
1467 struct xfs_buf *bp,
1468 int first,
1469 int last)
1470{
1471
1472 if (bp) {
1473 xfs_trans_buf_set_type(cur->bc_tp, bp, XFS_BLFT_BTREE_BUF);
1474 xfs_trans_log_buf(cur->bc_tp, bp,
1475 xfs_btree_key_offset(cur, first),
1476 xfs_btree_key_offset(cur, last + 1) - 1);
1477 } else {
1478 xfs_trans_log_inode(cur->bc_tp, cur->bc_ino.ip,
1479 xfs_ilog_fbroot(cur->bc_ino.whichfork));
1480 }
1481}
1482
1483/*
1484 * Log record values from the btree block.
1485 */
1486void
1487xfs_btree_log_recs(
1488 struct xfs_btree_cur *cur,
1489 struct xfs_buf *bp,
1490 int first,
1491 int last)
1492{
1493
1494 xfs_trans_buf_set_type(cur->bc_tp, bp, XFS_BLFT_BTREE_BUF);
1495 xfs_trans_log_buf(cur->bc_tp, bp,
1496 xfs_btree_rec_offset(cur, first),
1497 xfs_btree_rec_offset(cur, last + 1) - 1);
1498
1499}
1500
1501/*
1502 * Log block pointer fields from a btree block (nonleaf).
1503 */
1504STATIC void
1505xfs_btree_log_ptrs(
1506 struct xfs_btree_cur *cur, /* btree cursor */
1507 struct xfs_buf *bp, /* buffer containing btree block */
1508 int first, /* index of first pointer to log */
1509 int last) /* index of last pointer to log */
1510{
1511
1512 if (bp) {
1513 struct xfs_btree_block *block = XFS_BUF_TO_BLOCK(bp);
1514 int level = xfs_btree_get_level(block);
1515
1516 xfs_trans_buf_set_type(cur->bc_tp, bp, XFS_BLFT_BTREE_BUF);
1517 xfs_trans_log_buf(cur->bc_tp, bp,
1518 xfs_btree_ptr_offset(cur, first, level),
1519 xfs_btree_ptr_offset(cur, last + 1, level) - 1);
1520 } else {
1521 xfs_trans_log_inode(cur->bc_tp, cur->bc_ino.ip,
1522 xfs_ilog_fbroot(cur->bc_ino.whichfork));
1523 }
1524
1525}
1526
1527/*
1528 * Log fields from a btree block header.
1529 */
1530void
1531xfs_btree_log_block(
1532 struct xfs_btree_cur *cur, /* btree cursor */
1533 struct xfs_buf *bp, /* buffer containing btree block */
1534 uint32_t fields) /* mask of fields: XFS_BB_... */
1535{
1536 int first; /* first byte offset logged */
1537 int last; /* last byte offset logged */
1538 static const short soffsets[] = { /* table of offsets (short) */
1539 offsetof(struct xfs_btree_block, bb_magic),
1540 offsetof(struct xfs_btree_block, bb_level),
1541 offsetof(struct xfs_btree_block, bb_numrecs),
1542 offsetof(struct xfs_btree_block, bb_u.s.bb_leftsib),
1543 offsetof(struct xfs_btree_block, bb_u.s.bb_rightsib),
1544 offsetof(struct xfs_btree_block, bb_u.s.bb_blkno),
1545 offsetof(struct xfs_btree_block, bb_u.s.bb_lsn),
1546 offsetof(struct xfs_btree_block, bb_u.s.bb_uuid),
1547 offsetof(struct xfs_btree_block, bb_u.s.bb_owner),
1548 offsetof(struct xfs_btree_block, bb_u.s.bb_crc),
1549 XFS_BTREE_SBLOCK_CRC_LEN
1550 };
1551 static const short loffsets[] = { /* table of offsets (long) */
1552 offsetof(struct xfs_btree_block, bb_magic),
1553 offsetof(struct xfs_btree_block, bb_level),
1554 offsetof(struct xfs_btree_block, bb_numrecs),
1555 offsetof(struct xfs_btree_block, bb_u.l.bb_leftsib),
1556 offsetof(struct xfs_btree_block, bb_u.l.bb_rightsib),
1557 offsetof(struct xfs_btree_block, bb_u.l.bb_blkno),
1558 offsetof(struct xfs_btree_block, bb_u.l.bb_lsn),
1559 offsetof(struct xfs_btree_block, bb_u.l.bb_uuid),
1560 offsetof(struct xfs_btree_block, bb_u.l.bb_owner),
1561 offsetof(struct xfs_btree_block, bb_u.l.bb_crc),
1562 offsetof(struct xfs_btree_block, bb_u.l.bb_pad),
1563 XFS_BTREE_LBLOCK_CRC_LEN
1564 };
1565
1566 if (bp) {
1567 int nbits;
1568
1569 if (cur->bc_flags & XFS_BTREE_CRC_BLOCKS) {
1570 /*
1571 * We don't log the CRC when updating a btree
1572 * block but instead recreate it during log
1573 * recovery. As the log buffers have checksums
1574 * of their own this is safe and avoids logging a crc
1575 * update in a lot of places.
1576 */
1577 if (fields == XFS_BB_ALL_BITS)
1578 fields = XFS_BB_ALL_BITS_CRC;
1579 nbits = XFS_BB_NUM_BITS_CRC;
1580 } else {
1581 nbits = XFS_BB_NUM_BITS;
1582 }
1583 xfs_btree_offsets(fields,
1584 (cur->bc_flags & XFS_BTREE_LONG_PTRS) ?
1585 loffsets : soffsets,
1586 nbits, &first, &last);
1587 xfs_trans_buf_set_type(cur->bc_tp, bp, XFS_BLFT_BTREE_BUF);
1588 xfs_trans_log_buf(cur->bc_tp, bp, first, last);
1589 } else {
1590 xfs_trans_log_inode(cur->bc_tp, cur->bc_ino.ip,
1591 xfs_ilog_fbroot(cur->bc_ino.whichfork));
1592 }
1593}
1594
1595/*
1596 * Increment cursor by one record at the level.
1597 * For nonzero levels the leaf-ward information is untouched.
1598 */
1599int /* error */
1600xfs_btree_increment(
1601 struct xfs_btree_cur *cur,
1602 int level,
1603 int *stat) /* success/failure */
1604{
1605 struct xfs_btree_block *block;
1606 union xfs_btree_ptr ptr;
1607 struct xfs_buf *bp;
1608 int error; /* error return value */
1609 int lev;
1610
1611 ASSERT(level < cur->bc_nlevels);
1612
1613 /* Read-ahead to the right at this level. */
1614 xfs_btree_readahead(cur, level, XFS_BTCUR_RIGHTRA);
1615
1616 /* Get a pointer to the btree block. */
1617 block = xfs_btree_get_block(cur, level, &bp);
1618
1619#ifdef DEBUG
1620 error = xfs_btree_check_block(cur, block, level, bp);
1621 if (error)
1622 goto error0;
1623#endif
1624
1625 /* We're done if we remain in the block after the increment. */
1626 if (++cur->bc_levels[level].ptr <= xfs_btree_get_numrecs(block))
1627 goto out1;
1628
1629 /* Fail if we just went off the right edge of the tree. */
1630 xfs_btree_get_sibling(cur, block, &ptr, XFS_BB_RIGHTSIB);
1631 if (xfs_btree_ptr_is_null(cur, &ptr))
1632 goto out0;
1633
1634 XFS_BTREE_STATS_INC(cur, increment);
1635
1636 /*
1637 * March up the tree incrementing pointers.
1638 * Stop when we don't go off the right edge of a block.
1639 */
1640 for (lev = level + 1; lev < cur->bc_nlevels; lev++) {
1641 block = xfs_btree_get_block(cur, lev, &bp);
1642
1643#ifdef DEBUG
1644 error = xfs_btree_check_block(cur, block, lev, bp);
1645 if (error)
1646 goto error0;
1647#endif
1648
1649 if (++cur->bc_levels[lev].ptr <= xfs_btree_get_numrecs(block))
1650 break;
1651
1652 /* Read-ahead the right block for the next loop. */
1653 xfs_btree_readahead(cur, lev, XFS_BTCUR_RIGHTRA);
1654 }
1655
1656 /*
1657 * If we went off the root then we are either seriously
1658 * confused or have the tree root in an inode.
1659 */
1660 if (lev == cur->bc_nlevels) {
1661 if (cur->bc_flags & XFS_BTREE_ROOT_IN_INODE)
1662 goto out0;
1663 ASSERT(0);
1664 error = -EFSCORRUPTED;
1665 goto error0;
1666 }
1667 ASSERT(lev < cur->bc_nlevels);
1668
1669 /*
1670 * Now walk back down the tree, fixing up the cursor's buffer
1671 * pointers and key numbers.
1672 */
1673 for (block = xfs_btree_get_block(cur, lev, &bp); lev > level; ) {
1674 union xfs_btree_ptr *ptrp;
1675
1676 ptrp = xfs_btree_ptr_addr(cur, cur->bc_levels[lev].ptr, block);
1677 --lev;
1678 error = xfs_btree_read_buf_block(cur, ptrp, 0, &block, &bp);
1679 if (error)
1680 goto error0;
1681
1682 xfs_btree_setbuf(cur, lev, bp);
1683 cur->bc_levels[lev].ptr = 1;
1684 }
1685out1:
1686 *stat = 1;
1687 return 0;
1688
1689out0:
1690 *stat = 0;
1691 return 0;
1692
1693error0:
1694 return error;
1695}
1696
1697/*
1698 * Decrement cursor by one record at the level.
1699 * For nonzero levels the leaf-ward information is untouched.
1700 */
1701int /* error */
1702xfs_btree_decrement(
1703 struct xfs_btree_cur *cur,
1704 int level,
1705 int *stat) /* success/failure */
1706{
1707 struct xfs_btree_block *block;
1708 struct xfs_buf *bp;
1709 int error; /* error return value */
1710 int lev;
1711 union xfs_btree_ptr ptr;
1712
1713 ASSERT(level < cur->bc_nlevels);
1714
1715 /* Read-ahead to the left at this level. */
1716 xfs_btree_readahead(cur, level, XFS_BTCUR_LEFTRA);
1717
1718 /* We're done if we remain in the block after the decrement. */
1719 if (--cur->bc_levels[level].ptr > 0)
1720 goto out1;
1721
1722 /* Get a pointer to the btree block. */
1723 block = xfs_btree_get_block(cur, level, &bp);
1724
1725#ifdef DEBUG
1726 error = xfs_btree_check_block(cur, block, level, bp);
1727 if (error)
1728 goto error0;
1729#endif
1730
1731 /* Fail if we just went off the left edge of the tree. */
1732 xfs_btree_get_sibling(cur, block, &ptr, XFS_BB_LEFTSIB);
1733 if (xfs_btree_ptr_is_null(cur, &ptr))
1734 goto out0;
1735
1736 XFS_BTREE_STATS_INC(cur, decrement);
1737
1738 /*
1739 * March up the tree decrementing pointers.
1740 * Stop when we don't go off the left edge of a block.
1741 */
1742 for (lev = level + 1; lev < cur->bc_nlevels; lev++) {
1743 if (--cur->bc_levels[lev].ptr > 0)
1744 break;
1745 /* Read-ahead the left block for the next loop. */
1746 xfs_btree_readahead(cur, lev, XFS_BTCUR_LEFTRA);
1747 }
1748
1749 /*
1750 * If we went off the root then we are seriously confused.
1751 * or the root of the tree is in an inode.
1752 */
1753 if (lev == cur->bc_nlevels) {
1754 if (cur->bc_flags & XFS_BTREE_ROOT_IN_INODE)
1755 goto out0;
1756 ASSERT(0);
1757 error = -EFSCORRUPTED;
1758 goto error0;
1759 }
1760 ASSERT(lev < cur->bc_nlevels);
1761
1762 /*
1763 * Now walk back down the tree, fixing up the cursor's buffer
1764 * pointers and key numbers.
1765 */
1766 for (block = xfs_btree_get_block(cur, lev, &bp); lev > level; ) {
1767 union xfs_btree_ptr *ptrp;
1768
1769 ptrp = xfs_btree_ptr_addr(cur, cur->bc_levels[lev].ptr, block);
1770 --lev;
1771 error = xfs_btree_read_buf_block(cur, ptrp, 0, &block, &bp);
1772 if (error)
1773 goto error0;
1774 xfs_btree_setbuf(cur, lev, bp);
1775 cur->bc_levels[lev].ptr = xfs_btree_get_numrecs(block);
1776 }
1777out1:
1778 *stat = 1;
1779 return 0;
1780
1781out0:
1782 *stat = 0;
1783 return 0;
1784
1785error0:
1786 return error;
1787}
1788
1789int
1790xfs_btree_lookup_get_block(
1791 struct xfs_btree_cur *cur, /* btree cursor */
1792 int level, /* level in the btree */
1793 const union xfs_btree_ptr *pp, /* ptr to btree block */
1794 struct xfs_btree_block **blkp) /* return btree block */
1795{
1796 struct xfs_buf *bp; /* buffer pointer for btree block */
1797 xfs_daddr_t daddr;
1798 int error = 0;
1799
1800 /* special case the root block if in an inode */
1801 if ((cur->bc_flags & XFS_BTREE_ROOT_IN_INODE) &&
1802 (level == cur->bc_nlevels - 1)) {
1803 *blkp = xfs_btree_get_iroot(cur);
1804 return 0;
1805 }
1806
1807 /*
1808 * If the old buffer at this level for the disk address we are
1809 * looking for re-use it.
1810 *
1811 * Otherwise throw it away and get a new one.
1812 */
1813 bp = cur->bc_levels[level].bp;
1814 error = xfs_btree_ptr_to_daddr(cur, pp, &daddr);
1815 if (error)
1816 return error;
1817 if (bp && xfs_buf_daddr(bp) == daddr) {
1818 *blkp = XFS_BUF_TO_BLOCK(bp);
1819 return 0;
1820 }
1821
1822 error = xfs_btree_read_buf_block(cur, pp, 0, blkp, &bp);
1823 if (error)
1824 return error;
1825
1826 /* Check the inode owner since the verifiers don't. */
1827 if (xfs_has_crc(cur->bc_mp) &&
1828 !(cur->bc_ino.flags & XFS_BTCUR_BMBT_INVALID_OWNER) &&
1829 (cur->bc_flags & XFS_BTREE_LONG_PTRS) &&
1830 be64_to_cpu((*blkp)->bb_u.l.bb_owner) !=
1831 cur->bc_ino.ip->i_ino)
1832 goto out_bad;
1833
1834 /* Did we get the level we were looking for? */
1835 if (be16_to_cpu((*blkp)->bb_level) != level)
1836 goto out_bad;
1837
1838 /* Check that internal nodes have at least one record. */
1839 if (level != 0 && be16_to_cpu((*blkp)->bb_numrecs) == 0)
1840 goto out_bad;
1841
1842 xfs_btree_setbuf(cur, level, bp);
1843 return 0;
1844
1845out_bad:
1846 *blkp = NULL;
1847 xfs_buf_mark_corrupt(bp);
1848 xfs_trans_brelse(cur->bc_tp, bp);
1849 return -EFSCORRUPTED;
1850}
1851
1852/*
1853 * Get current search key. For level 0 we don't actually have a key
1854 * structure so we make one up from the record. For all other levels
1855 * we just return the right key.
1856 */
1857STATIC union xfs_btree_key *
1858xfs_lookup_get_search_key(
1859 struct xfs_btree_cur *cur,
1860 int level,
1861 int keyno,
1862 struct xfs_btree_block *block,
1863 union xfs_btree_key *kp)
1864{
1865 if (level == 0) {
1866 cur->bc_ops->init_key_from_rec(kp,
1867 xfs_btree_rec_addr(cur, keyno, block));
1868 return kp;
1869 }
1870
1871 return xfs_btree_key_addr(cur, keyno, block);
1872}
1873
1874/*
1875 * Lookup the record. The cursor is made to point to it, based on dir.
1876 * stat is set to 0 if can't find any such record, 1 for success.
1877 */
1878int /* error */
1879xfs_btree_lookup(
1880 struct xfs_btree_cur *cur, /* btree cursor */
1881 xfs_lookup_t dir, /* <=, ==, or >= */
1882 int *stat) /* success/failure */
1883{
1884 struct xfs_btree_block *block; /* current btree block */
1885 int64_t diff; /* difference for the current key */
1886 int error; /* error return value */
1887 int keyno; /* current key number */
1888 int level; /* level in the btree */
1889 union xfs_btree_ptr *pp; /* ptr to btree block */
1890 union xfs_btree_ptr ptr; /* ptr to btree block */
1891
1892 XFS_BTREE_STATS_INC(cur, lookup);
1893
1894 /* No such thing as a zero-level tree. */
1895 if (XFS_IS_CORRUPT(cur->bc_mp, cur->bc_nlevels == 0))
1896 return -EFSCORRUPTED;
1897
1898 block = NULL;
1899 keyno = 0;
1900
1901 /* initialise start pointer from cursor */
1902 cur->bc_ops->init_ptr_from_cur(cur, &ptr);
1903 pp = &ptr;
1904
1905 /*
1906 * Iterate over each level in the btree, starting at the root.
1907 * For each level above the leaves, find the key we need, based
1908 * on the lookup record, then follow the corresponding block
1909 * pointer down to the next level.
1910 */
1911 for (level = cur->bc_nlevels - 1, diff = 1; level >= 0; level--) {
1912 /* Get the block we need to do the lookup on. */
1913 error = xfs_btree_lookup_get_block(cur, level, pp, &block);
1914 if (error)
1915 goto error0;
1916
1917 if (diff == 0) {
1918 /*
1919 * If we already had a key match at a higher level, we
1920 * know we need to use the first entry in this block.
1921 */
1922 keyno = 1;
1923 } else {
1924 /* Otherwise search this block. Do a binary search. */
1925
1926 int high; /* high entry number */
1927 int low; /* low entry number */
1928
1929 /* Set low and high entry numbers, 1-based. */
1930 low = 1;
1931 high = xfs_btree_get_numrecs(block);
1932 if (!high) {
1933 /* Block is empty, must be an empty leaf. */
1934 if (level != 0 || cur->bc_nlevels != 1) {
1935 XFS_CORRUPTION_ERROR(__func__,
1936 XFS_ERRLEVEL_LOW,
1937 cur->bc_mp, block,
1938 sizeof(*block));
1939 return -EFSCORRUPTED;
1940 }
1941
1942 cur->bc_levels[0].ptr = dir != XFS_LOOKUP_LE;
1943 *stat = 0;
1944 return 0;
1945 }
1946
1947 /* Binary search the block. */
1948 while (low <= high) {
1949 union xfs_btree_key key;
1950 union xfs_btree_key *kp;
1951
1952 XFS_BTREE_STATS_INC(cur, compare);
1953
1954 /* keyno is average of low and high. */
1955 keyno = (low + high) >> 1;
1956
1957 /* Get current search key */
1958 kp = xfs_lookup_get_search_key(cur, level,
1959 keyno, block, &key);
1960
1961 /*
1962 * Compute difference to get next direction:
1963 * - less than, move right
1964 * - greater than, move left
1965 * - equal, we're done
1966 */
1967 diff = cur->bc_ops->key_diff(cur, kp);
1968 if (diff < 0)
1969 low = keyno + 1;
1970 else if (diff > 0)
1971 high = keyno - 1;
1972 else
1973 break;
1974 }
1975 }
1976
1977 /*
1978 * If there are more levels, set up for the next level
1979 * by getting the block number and filling in the cursor.
1980 */
1981 if (level > 0) {
1982 /*
1983 * If we moved left, need the previous key number,
1984 * unless there isn't one.
1985 */
1986 if (diff > 0 && --keyno < 1)
1987 keyno = 1;
1988 pp = xfs_btree_ptr_addr(cur, keyno, block);
1989
1990 error = xfs_btree_debug_check_ptr(cur, pp, 0, level);
1991 if (error)
1992 goto error0;
1993
1994 cur->bc_levels[level].ptr = keyno;
1995 }
1996 }
1997
1998 /* Done with the search. See if we need to adjust the results. */
1999 if (dir != XFS_LOOKUP_LE && diff < 0) {
2000 keyno++;
2001 /*
2002 * If ge search and we went off the end of the block, but it's
2003 * not the last block, we're in the wrong block.
2004 */
2005 xfs_btree_get_sibling(cur, block, &ptr, XFS_BB_RIGHTSIB);
2006 if (dir == XFS_LOOKUP_GE &&
2007 keyno > xfs_btree_get_numrecs(block) &&
2008 !xfs_btree_ptr_is_null(cur, &ptr)) {
2009 int i;
2010
2011 cur->bc_levels[0].ptr = keyno;
2012 error = xfs_btree_increment(cur, 0, &i);
2013 if (error)
2014 goto error0;
2015 if (XFS_IS_CORRUPT(cur->bc_mp, i != 1))
2016 return -EFSCORRUPTED;
2017 *stat = 1;
2018 return 0;
2019 }
2020 } else if (dir == XFS_LOOKUP_LE && diff > 0)
2021 keyno--;
2022 cur->bc_levels[0].ptr = keyno;
2023
2024 /* Return if we succeeded or not. */
2025 if (keyno == 0 || keyno > xfs_btree_get_numrecs(block))
2026 *stat = 0;
2027 else if (dir != XFS_LOOKUP_EQ || diff == 0)
2028 *stat = 1;
2029 else
2030 *stat = 0;
2031 return 0;
2032
2033error0:
2034 return error;
2035}
2036
2037/* Find the high key storage area from a regular key. */
2038union xfs_btree_key *
2039xfs_btree_high_key_from_key(
2040 struct xfs_btree_cur *cur,
2041 union xfs_btree_key *key)
2042{
2043 ASSERT(cur->bc_flags & XFS_BTREE_OVERLAPPING);
2044 return (union xfs_btree_key *)((char *)key +
2045 (cur->bc_ops->key_len / 2));
2046}
2047
2048/* Determine the low (and high if overlapped) keys of a leaf block */
2049STATIC void
2050xfs_btree_get_leaf_keys(
2051 struct xfs_btree_cur *cur,
2052 struct xfs_btree_block *block,
2053 union xfs_btree_key *key)
2054{
2055 union xfs_btree_key max_hkey;
2056 union xfs_btree_key hkey;
2057 union xfs_btree_rec *rec;
2058 union xfs_btree_key *high;
2059 int n;
2060
2061 rec = xfs_btree_rec_addr(cur, 1, block);
2062 cur->bc_ops->init_key_from_rec(key, rec);
2063
2064 if (cur->bc_flags & XFS_BTREE_OVERLAPPING) {
2065
2066 cur->bc_ops->init_high_key_from_rec(&max_hkey, rec);
2067 for (n = 2; n <= xfs_btree_get_numrecs(block); n++) {
2068 rec = xfs_btree_rec_addr(cur, n, block);
2069 cur->bc_ops->init_high_key_from_rec(&hkey, rec);
2070 if (xfs_btree_keycmp_gt(cur, &hkey, &max_hkey))
2071 max_hkey = hkey;
2072 }
2073
2074 high = xfs_btree_high_key_from_key(cur, key);
2075 memcpy(high, &max_hkey, cur->bc_ops->key_len / 2);
2076 }
2077}
2078
2079/* Determine the low (and high if overlapped) keys of a node block */
2080STATIC void
2081xfs_btree_get_node_keys(
2082 struct xfs_btree_cur *cur,
2083 struct xfs_btree_block *block,
2084 union xfs_btree_key *key)
2085{
2086 union xfs_btree_key *hkey;
2087 union xfs_btree_key *max_hkey;
2088 union xfs_btree_key *high;
2089 int n;
2090
2091 if (cur->bc_flags & XFS_BTREE_OVERLAPPING) {
2092 memcpy(key, xfs_btree_key_addr(cur, 1, block),
2093 cur->bc_ops->key_len / 2);
2094
2095 max_hkey = xfs_btree_high_key_addr(cur, 1, block);
2096 for (n = 2; n <= xfs_btree_get_numrecs(block); n++) {
2097 hkey = xfs_btree_high_key_addr(cur, n, block);
2098 if (xfs_btree_keycmp_gt(cur, hkey, max_hkey))
2099 max_hkey = hkey;
2100 }
2101
2102 high = xfs_btree_high_key_from_key(cur, key);
2103 memcpy(high, max_hkey, cur->bc_ops->key_len / 2);
2104 } else {
2105 memcpy(key, xfs_btree_key_addr(cur, 1, block),
2106 cur->bc_ops->key_len);
2107 }
2108}
2109
2110/* Derive the keys for any btree block. */
2111void
2112xfs_btree_get_keys(
2113 struct xfs_btree_cur *cur,
2114 struct xfs_btree_block *block,
2115 union xfs_btree_key *key)
2116{
2117 if (be16_to_cpu(block->bb_level) == 0)
2118 xfs_btree_get_leaf_keys(cur, block, key);
2119 else
2120 xfs_btree_get_node_keys(cur, block, key);
2121}
2122
2123/*
2124 * Decide if we need to update the parent keys of a btree block. For
2125 * a standard btree this is only necessary if we're updating the first
2126 * record/key. For an overlapping btree, we must always update the
2127 * keys because the highest key can be in any of the records or keys
2128 * in the block.
2129 */
2130static inline bool
2131xfs_btree_needs_key_update(
2132 struct xfs_btree_cur *cur,
2133 int ptr)
2134{
2135 return (cur->bc_flags & XFS_BTREE_OVERLAPPING) || ptr == 1;
2136}
2137
2138/*
2139 * Update the low and high parent keys of the given level, progressing
2140 * towards the root. If force_all is false, stop if the keys for a given
2141 * level do not need updating.
2142 */
2143STATIC int
2144__xfs_btree_updkeys(
2145 struct xfs_btree_cur *cur,
2146 int level,
2147 struct xfs_btree_block *block,
2148 struct xfs_buf *bp0,
2149 bool force_all)
2150{
2151 union xfs_btree_key key; /* keys from current level */
2152 union xfs_btree_key *lkey; /* keys from the next level up */
2153 union xfs_btree_key *hkey;
2154 union xfs_btree_key *nlkey; /* keys from the next level up */
2155 union xfs_btree_key *nhkey;
2156 struct xfs_buf *bp;
2157 int ptr;
2158
2159 ASSERT(cur->bc_flags & XFS_BTREE_OVERLAPPING);
2160
2161 /* Exit if there aren't any parent levels to update. */
2162 if (level + 1 >= cur->bc_nlevels)
2163 return 0;
2164
2165 trace_xfs_btree_updkeys(cur, level, bp0);
2166
2167 lkey = &key;
2168 hkey = xfs_btree_high_key_from_key(cur, lkey);
2169 xfs_btree_get_keys(cur, block, lkey);
2170 for (level++; level < cur->bc_nlevels; level++) {
2171#ifdef DEBUG
2172 int error;
2173#endif
2174 block = xfs_btree_get_block(cur, level, &bp);
2175 trace_xfs_btree_updkeys(cur, level, bp);
2176#ifdef DEBUG
2177 error = xfs_btree_check_block(cur, block, level, bp);
2178 if (error)
2179 return error;
2180#endif
2181 ptr = cur->bc_levels[level].ptr;
2182 nlkey = xfs_btree_key_addr(cur, ptr, block);
2183 nhkey = xfs_btree_high_key_addr(cur, ptr, block);
2184 if (!force_all &&
2185 xfs_btree_keycmp_eq(cur, nlkey, lkey) &&
2186 xfs_btree_keycmp_eq(cur, nhkey, hkey))
2187 break;
2188 xfs_btree_copy_keys(cur, nlkey, lkey, 1);
2189 xfs_btree_log_keys(cur, bp, ptr, ptr);
2190 if (level + 1 >= cur->bc_nlevels)
2191 break;
2192 xfs_btree_get_node_keys(cur, block, lkey);
2193 }
2194
2195 return 0;
2196}
2197
2198/* Update all the keys from some level in cursor back to the root. */
2199STATIC int
2200xfs_btree_updkeys_force(
2201 struct xfs_btree_cur *cur,
2202 int level)
2203{
2204 struct xfs_buf *bp;
2205 struct xfs_btree_block *block;
2206
2207 block = xfs_btree_get_block(cur, level, &bp);
2208 return __xfs_btree_updkeys(cur, level, block, bp, true);
2209}
2210
2211/*
2212 * Update the parent keys of the given level, progressing towards the root.
2213 */
2214STATIC int
2215xfs_btree_update_keys(
2216 struct xfs_btree_cur *cur,
2217 int level)
2218{
2219 struct xfs_btree_block *block;
2220 struct xfs_buf *bp;
2221 union xfs_btree_key *kp;
2222 union xfs_btree_key key;
2223 int ptr;
2224
2225 ASSERT(level >= 0);
2226
2227 block = xfs_btree_get_block(cur, level, &bp);
2228 if (cur->bc_flags & XFS_BTREE_OVERLAPPING)
2229 return __xfs_btree_updkeys(cur, level, block, bp, false);
2230
2231 /*
2232 * Go up the tree from this level toward the root.
2233 * At each level, update the key value to the value input.
2234 * Stop when we reach a level where the cursor isn't pointing
2235 * at the first entry in the block.
2236 */
2237 xfs_btree_get_keys(cur, block, &key);
2238 for (level++, ptr = 1; ptr == 1 && level < cur->bc_nlevels; level++) {
2239#ifdef DEBUG
2240 int error;
2241#endif
2242 block = xfs_btree_get_block(cur, level, &bp);
2243#ifdef DEBUG
2244 error = xfs_btree_check_block(cur, block, level, bp);
2245 if (error)
2246 return error;
2247#endif
2248 ptr = cur->bc_levels[level].ptr;
2249 kp = xfs_btree_key_addr(cur, ptr, block);
2250 xfs_btree_copy_keys(cur, kp, &key, 1);
2251 xfs_btree_log_keys(cur, bp, ptr, ptr);
2252 }
2253
2254 return 0;
2255}
2256
2257/*
2258 * Update the record referred to by cur to the value in the
2259 * given record. This either works (return 0) or gets an
2260 * EFSCORRUPTED error.
2261 */
2262int
2263xfs_btree_update(
2264 struct xfs_btree_cur *cur,
2265 union xfs_btree_rec *rec)
2266{
2267 struct xfs_btree_block *block;
2268 struct xfs_buf *bp;
2269 int error;
2270 int ptr;
2271 union xfs_btree_rec *rp;
2272
2273 /* Pick up the current block. */
2274 block = xfs_btree_get_block(cur, 0, &bp);
2275
2276#ifdef DEBUG
2277 error = xfs_btree_check_block(cur, block, 0, bp);
2278 if (error)
2279 goto error0;
2280#endif
2281 /* Get the address of the rec to be updated. */
2282 ptr = cur->bc_levels[0].ptr;
2283 rp = xfs_btree_rec_addr(cur, ptr, block);
2284
2285 /* Fill in the new contents and log them. */
2286 xfs_btree_copy_recs(cur, rp, rec, 1);
2287 xfs_btree_log_recs(cur, bp, ptr, ptr);
2288
2289 /*
2290 * If we are tracking the last record in the tree and
2291 * we are at the far right edge of the tree, update it.
2292 */
2293 if (xfs_btree_is_lastrec(cur, block, 0)) {
2294 cur->bc_ops->update_lastrec(cur, block, rec,
2295 ptr, LASTREC_UPDATE);
2296 }
2297
2298 /* Pass new key value up to our parent. */
2299 if (xfs_btree_needs_key_update(cur, ptr)) {
2300 error = xfs_btree_update_keys(cur, 0);
2301 if (error)
2302 goto error0;
2303 }
2304
2305 return 0;
2306
2307error0:
2308 return error;
2309}
2310
2311/*
2312 * Move 1 record left from cur/level if possible.
2313 * Update cur to reflect the new path.
2314 */
2315STATIC int /* error */
2316xfs_btree_lshift(
2317 struct xfs_btree_cur *cur,
2318 int level,
2319 int *stat) /* success/failure */
2320{
2321 struct xfs_buf *lbp; /* left buffer pointer */
2322 struct xfs_btree_block *left; /* left btree block */
2323 int lrecs; /* left record count */
2324 struct xfs_buf *rbp; /* right buffer pointer */
2325 struct xfs_btree_block *right; /* right btree block */
2326 struct xfs_btree_cur *tcur; /* temporary btree cursor */
2327 int rrecs; /* right record count */
2328 union xfs_btree_ptr lptr; /* left btree pointer */
2329 union xfs_btree_key *rkp = NULL; /* right btree key */
2330 union xfs_btree_ptr *rpp = NULL; /* right address pointer */
2331 union xfs_btree_rec *rrp = NULL; /* right record pointer */
2332 int error; /* error return value */
2333 int i;
2334
2335 if ((cur->bc_flags & XFS_BTREE_ROOT_IN_INODE) &&
2336 level == cur->bc_nlevels - 1)
2337 goto out0;
2338
2339 /* Set up variables for this block as "right". */
2340 right = xfs_btree_get_block(cur, level, &rbp);
2341
2342#ifdef DEBUG
2343 error = xfs_btree_check_block(cur, right, level, rbp);
2344 if (error)
2345 goto error0;
2346#endif
2347
2348 /* If we've got no left sibling then we can't shift an entry left. */
2349 xfs_btree_get_sibling(cur, right, &lptr, XFS_BB_LEFTSIB);
2350 if (xfs_btree_ptr_is_null(cur, &lptr))
2351 goto out0;
2352
2353 /*
2354 * If the cursor entry is the one that would be moved, don't
2355 * do it... it's too complicated.
2356 */
2357 if (cur->bc_levels[level].ptr <= 1)
2358 goto out0;
2359
2360 /* Set up the left neighbor as "left". */
2361 error = xfs_btree_read_buf_block(cur, &lptr, 0, &left, &lbp);
2362 if (error)
2363 goto error0;
2364
2365 /* If it's full, it can't take another entry. */
2366 lrecs = xfs_btree_get_numrecs(left);
2367 if (lrecs == cur->bc_ops->get_maxrecs(cur, level))
2368 goto out0;
2369
2370 rrecs = xfs_btree_get_numrecs(right);
2371
2372 /*
2373 * We add one entry to the left side and remove one for the right side.
2374 * Account for it here, the changes will be updated on disk and logged
2375 * later.
2376 */
2377 lrecs++;
2378 rrecs--;
2379
2380 XFS_BTREE_STATS_INC(cur, lshift);
2381 XFS_BTREE_STATS_ADD(cur, moves, 1);
2382
2383 /*
2384 * If non-leaf, copy a key and a ptr to the left block.
2385 * Log the changes to the left block.
2386 */
2387 if (level > 0) {
2388 /* It's a non-leaf. Move keys and pointers. */
2389 union xfs_btree_key *lkp; /* left btree key */
2390 union xfs_btree_ptr *lpp; /* left address pointer */
2391
2392 lkp = xfs_btree_key_addr(cur, lrecs, left);
2393 rkp = xfs_btree_key_addr(cur, 1, right);
2394
2395 lpp = xfs_btree_ptr_addr(cur, lrecs, left);
2396 rpp = xfs_btree_ptr_addr(cur, 1, right);
2397
2398 error = xfs_btree_debug_check_ptr(cur, rpp, 0, level);
2399 if (error)
2400 goto error0;
2401
2402 xfs_btree_copy_keys(cur, lkp, rkp, 1);
2403 xfs_btree_copy_ptrs(cur, lpp, rpp, 1);
2404
2405 xfs_btree_log_keys(cur, lbp, lrecs, lrecs);
2406 xfs_btree_log_ptrs(cur, lbp, lrecs, lrecs);
2407
2408 ASSERT(cur->bc_ops->keys_inorder(cur,
2409 xfs_btree_key_addr(cur, lrecs - 1, left), lkp));
2410 } else {
2411 /* It's a leaf. Move records. */
2412 union xfs_btree_rec *lrp; /* left record pointer */
2413
2414 lrp = xfs_btree_rec_addr(cur, lrecs, left);
2415 rrp = xfs_btree_rec_addr(cur, 1, right);
2416
2417 xfs_btree_copy_recs(cur, lrp, rrp, 1);
2418 xfs_btree_log_recs(cur, lbp, lrecs, lrecs);
2419
2420 ASSERT(cur->bc_ops->recs_inorder(cur,
2421 xfs_btree_rec_addr(cur, lrecs - 1, left), lrp));
2422 }
2423
2424 xfs_btree_set_numrecs(left, lrecs);
2425 xfs_btree_log_block(cur, lbp, XFS_BB_NUMRECS);
2426
2427 xfs_btree_set_numrecs(right, rrecs);
2428 xfs_btree_log_block(cur, rbp, XFS_BB_NUMRECS);
2429
2430 /*
2431 * Slide the contents of right down one entry.
2432 */
2433 XFS_BTREE_STATS_ADD(cur, moves, rrecs - 1);
2434 if (level > 0) {
2435 /* It's a nonleaf. operate on keys and ptrs */
2436 for (i = 0; i < rrecs; i++) {
2437 error = xfs_btree_debug_check_ptr(cur, rpp, i + 1, level);
2438 if (error)
2439 goto error0;
2440 }
2441
2442 xfs_btree_shift_keys(cur,
2443 xfs_btree_key_addr(cur, 2, right),
2444 -1, rrecs);
2445 xfs_btree_shift_ptrs(cur,
2446 xfs_btree_ptr_addr(cur, 2, right),
2447 -1, rrecs);
2448
2449 xfs_btree_log_keys(cur, rbp, 1, rrecs);
2450 xfs_btree_log_ptrs(cur, rbp, 1, rrecs);
2451 } else {
2452 /* It's a leaf. operate on records */
2453 xfs_btree_shift_recs(cur,
2454 xfs_btree_rec_addr(cur, 2, right),
2455 -1, rrecs);
2456 xfs_btree_log_recs(cur, rbp, 1, rrecs);
2457 }
2458
2459 /*
2460 * Using a temporary cursor, update the parent key values of the
2461 * block on the left.
2462 */
2463 if (cur->bc_flags & XFS_BTREE_OVERLAPPING) {
2464 error = xfs_btree_dup_cursor(cur, &tcur);
2465 if (error)
2466 goto error0;
2467 i = xfs_btree_firstrec(tcur, level);
2468 if (XFS_IS_CORRUPT(tcur->bc_mp, i != 1)) {
2469 error = -EFSCORRUPTED;
2470 goto error0;
2471 }
2472
2473 error = xfs_btree_decrement(tcur, level, &i);
2474 if (error)
2475 goto error1;
2476
2477 /* Update the parent high keys of the left block, if needed. */
2478 error = xfs_btree_update_keys(tcur, level);
2479 if (error)
2480 goto error1;
2481
2482 xfs_btree_del_cursor(tcur, XFS_BTREE_NOERROR);
2483 }
2484
2485 /* Update the parent keys of the right block. */
2486 error = xfs_btree_update_keys(cur, level);
2487 if (error)
2488 goto error0;
2489
2490 /* Slide the cursor value left one. */
2491 cur->bc_levels[level].ptr--;
2492
2493 *stat = 1;
2494 return 0;
2495
2496out0:
2497 *stat = 0;
2498 return 0;
2499
2500error0:
2501 return error;
2502
2503error1:
2504 xfs_btree_del_cursor(tcur, XFS_BTREE_ERROR);
2505 return error;
2506}
2507
2508/*
2509 * Move 1 record right from cur/level if possible.
2510 * Update cur to reflect the new path.
2511 */
2512STATIC int /* error */
2513xfs_btree_rshift(
2514 struct xfs_btree_cur *cur,
2515 int level,
2516 int *stat) /* success/failure */
2517{
2518 struct xfs_buf *lbp; /* left buffer pointer */
2519 struct xfs_btree_block *left; /* left btree block */
2520 struct xfs_buf *rbp; /* right buffer pointer */
2521 struct xfs_btree_block *right; /* right btree block */
2522 struct xfs_btree_cur *tcur; /* temporary btree cursor */
2523 union xfs_btree_ptr rptr; /* right block pointer */
2524 union xfs_btree_key *rkp; /* right btree key */
2525 int rrecs; /* right record count */
2526 int lrecs; /* left record count */
2527 int error; /* error return value */
2528 int i; /* loop counter */
2529
2530 if ((cur->bc_flags & XFS_BTREE_ROOT_IN_INODE) &&
2531 (level == cur->bc_nlevels - 1))
2532 goto out0;
2533
2534 /* Set up variables for this block as "left". */
2535 left = xfs_btree_get_block(cur, level, &lbp);
2536
2537#ifdef DEBUG
2538 error = xfs_btree_check_block(cur, left, level, lbp);
2539 if (error)
2540 goto error0;
2541#endif
2542
2543 /* If we've got no right sibling then we can't shift an entry right. */
2544 xfs_btree_get_sibling(cur, left, &rptr, XFS_BB_RIGHTSIB);
2545 if (xfs_btree_ptr_is_null(cur, &rptr))
2546 goto out0;
2547
2548 /*
2549 * If the cursor entry is the one that would be moved, don't
2550 * do it... it's too complicated.
2551 */
2552 lrecs = xfs_btree_get_numrecs(left);
2553 if (cur->bc_levels[level].ptr >= lrecs)
2554 goto out0;
2555
2556 /* Set up the right neighbor as "right". */
2557 error = xfs_btree_read_buf_block(cur, &rptr, 0, &right, &rbp);
2558 if (error)
2559 goto error0;
2560
2561 /* If it's full, it can't take another entry. */
2562 rrecs = xfs_btree_get_numrecs(right);
2563 if (rrecs == cur->bc_ops->get_maxrecs(cur, level))
2564 goto out0;
2565
2566 XFS_BTREE_STATS_INC(cur, rshift);
2567 XFS_BTREE_STATS_ADD(cur, moves, rrecs);
2568
2569 /*
2570 * Make a hole at the start of the right neighbor block, then
2571 * copy the last left block entry to the hole.
2572 */
2573 if (level > 0) {
2574 /* It's a nonleaf. make a hole in the keys and ptrs */
2575 union xfs_btree_key *lkp;
2576 union xfs_btree_ptr *lpp;
2577 union xfs_btree_ptr *rpp;
2578
2579 lkp = xfs_btree_key_addr(cur, lrecs, left);
2580 lpp = xfs_btree_ptr_addr(cur, lrecs, left);
2581 rkp = xfs_btree_key_addr(cur, 1, right);
2582 rpp = xfs_btree_ptr_addr(cur, 1, right);
2583
2584 for (i = rrecs - 1; i >= 0; i--) {
2585 error = xfs_btree_debug_check_ptr(cur, rpp, i, level);
2586 if (error)
2587 goto error0;
2588 }
2589
2590 xfs_btree_shift_keys(cur, rkp, 1, rrecs);
2591 xfs_btree_shift_ptrs(cur, rpp, 1, rrecs);
2592
2593 error = xfs_btree_debug_check_ptr(cur, lpp, 0, level);
2594 if (error)
2595 goto error0;
2596
2597 /* Now put the new data in, and log it. */
2598 xfs_btree_copy_keys(cur, rkp, lkp, 1);
2599 xfs_btree_copy_ptrs(cur, rpp, lpp, 1);
2600
2601 xfs_btree_log_keys(cur, rbp, 1, rrecs + 1);
2602 xfs_btree_log_ptrs(cur, rbp, 1, rrecs + 1);
2603
2604 ASSERT(cur->bc_ops->keys_inorder(cur, rkp,
2605 xfs_btree_key_addr(cur, 2, right)));
2606 } else {
2607 /* It's a leaf. make a hole in the records */
2608 union xfs_btree_rec *lrp;
2609 union xfs_btree_rec *rrp;
2610
2611 lrp = xfs_btree_rec_addr(cur, lrecs, left);
2612 rrp = xfs_btree_rec_addr(cur, 1, right);
2613
2614 xfs_btree_shift_recs(cur, rrp, 1, rrecs);
2615
2616 /* Now put the new data in, and log it. */
2617 xfs_btree_copy_recs(cur, rrp, lrp, 1);
2618 xfs_btree_log_recs(cur, rbp, 1, rrecs + 1);
2619 }
2620
2621 /*
2622 * Decrement and log left's numrecs, bump and log right's numrecs.
2623 */
2624 xfs_btree_set_numrecs(left, --lrecs);
2625 xfs_btree_log_block(cur, lbp, XFS_BB_NUMRECS);
2626
2627 xfs_btree_set_numrecs(right, ++rrecs);
2628 xfs_btree_log_block(cur, rbp, XFS_BB_NUMRECS);
2629
2630 /*
2631 * Using a temporary cursor, update the parent key values of the
2632 * block on the right.
2633 */
2634 error = xfs_btree_dup_cursor(cur, &tcur);
2635 if (error)
2636 goto error0;
2637 i = xfs_btree_lastrec(tcur, level);
2638 if (XFS_IS_CORRUPT(tcur->bc_mp, i != 1)) {
2639 error = -EFSCORRUPTED;
2640 goto error0;
2641 }
2642
2643 error = xfs_btree_increment(tcur, level, &i);
2644 if (error)
2645 goto error1;
2646
2647 /* Update the parent high keys of the left block, if needed. */
2648 if (cur->bc_flags & XFS_BTREE_OVERLAPPING) {
2649 error = xfs_btree_update_keys(cur, level);
2650 if (error)
2651 goto error1;
2652 }
2653
2654 /* Update the parent keys of the right block. */
2655 error = xfs_btree_update_keys(tcur, level);
2656 if (error)
2657 goto error1;
2658
2659 xfs_btree_del_cursor(tcur, XFS_BTREE_NOERROR);
2660
2661 *stat = 1;
2662 return 0;
2663
2664out0:
2665 *stat = 0;
2666 return 0;
2667
2668error0:
2669 return error;
2670
2671error1:
2672 xfs_btree_del_cursor(tcur, XFS_BTREE_ERROR);
2673 return error;
2674}
2675
2676/*
2677 * Split cur/level block in half.
2678 * Return new block number and the key to its first
2679 * record (to be inserted into parent).
2680 */
2681STATIC int /* error */
2682__xfs_btree_split(
2683 struct xfs_btree_cur *cur,
2684 int level,
2685 union xfs_btree_ptr *ptrp,
2686 union xfs_btree_key *key,
2687 struct xfs_btree_cur **curp,
2688 int *stat) /* success/failure */
2689{
2690 union xfs_btree_ptr lptr; /* left sibling block ptr */
2691 struct xfs_buf *lbp; /* left buffer pointer */
2692 struct xfs_btree_block *left; /* left btree block */
2693 union xfs_btree_ptr rptr; /* right sibling block ptr */
2694 struct xfs_buf *rbp; /* right buffer pointer */
2695 struct xfs_btree_block *right; /* right btree block */
2696 union xfs_btree_ptr rrptr; /* right-right sibling ptr */
2697 struct xfs_buf *rrbp; /* right-right buffer pointer */
2698 struct xfs_btree_block *rrblock; /* right-right btree block */
2699 int lrecs;
2700 int rrecs;
2701 int src_index;
2702 int error; /* error return value */
2703 int i;
2704
2705 XFS_BTREE_STATS_INC(cur, split);
2706
2707 /* Set up left block (current one). */
2708 left = xfs_btree_get_block(cur, level, &lbp);
2709
2710#ifdef DEBUG
2711 error = xfs_btree_check_block(cur, left, level, lbp);
2712 if (error)
2713 goto error0;
2714#endif
2715
2716 xfs_btree_buf_to_ptr(cur, lbp, &lptr);
2717
2718 /* Allocate the new block. If we can't do it, we're toast. Give up. */
2719 error = cur->bc_ops->alloc_block(cur, &lptr, &rptr, stat);
2720 if (error)
2721 goto error0;
2722 if (*stat == 0)
2723 goto out0;
2724 XFS_BTREE_STATS_INC(cur, alloc);
2725
2726 /* Set up the new block as "right". */
2727 error = xfs_btree_get_buf_block(cur, &rptr, &right, &rbp);
2728 if (error)
2729 goto error0;
2730
2731 /* Fill in the btree header for the new right block. */
2732 xfs_btree_init_block_cur(cur, rbp, xfs_btree_get_level(left), 0);
2733
2734 /*
2735 * Split the entries between the old and the new block evenly.
2736 * Make sure that if there's an odd number of entries now, that
2737 * each new block will have the same number of entries.
2738 */
2739 lrecs = xfs_btree_get_numrecs(left);
2740 rrecs = lrecs / 2;
2741 if ((lrecs & 1) && cur->bc_levels[level].ptr <= rrecs + 1)
2742 rrecs++;
2743 src_index = (lrecs - rrecs + 1);
2744
2745 XFS_BTREE_STATS_ADD(cur, moves, rrecs);
2746
2747 /* Adjust numrecs for the later get_*_keys() calls. */
2748 lrecs -= rrecs;
2749 xfs_btree_set_numrecs(left, lrecs);
2750 xfs_btree_set_numrecs(right, xfs_btree_get_numrecs(right) + rrecs);
2751
2752 /*
2753 * Copy btree block entries from the left block over to the
2754 * new block, the right. Update the right block and log the
2755 * changes.
2756 */
2757 if (level > 0) {
2758 /* It's a non-leaf. Move keys and pointers. */
2759 union xfs_btree_key *lkp; /* left btree key */
2760 union xfs_btree_ptr *lpp; /* left address pointer */
2761 union xfs_btree_key *rkp; /* right btree key */
2762 union xfs_btree_ptr *rpp; /* right address pointer */
2763
2764 lkp = xfs_btree_key_addr(cur, src_index, left);
2765 lpp = xfs_btree_ptr_addr(cur, src_index, left);
2766 rkp = xfs_btree_key_addr(cur, 1, right);
2767 rpp = xfs_btree_ptr_addr(cur, 1, right);
2768
2769 for (i = src_index; i < rrecs; i++) {
2770 error = xfs_btree_debug_check_ptr(cur, lpp, i, level);
2771 if (error)
2772 goto error0;
2773 }
2774
2775 /* Copy the keys & pointers to the new block. */
2776 xfs_btree_copy_keys(cur, rkp, lkp, rrecs);
2777 xfs_btree_copy_ptrs(cur, rpp, lpp, rrecs);
2778
2779 xfs_btree_log_keys(cur, rbp, 1, rrecs);
2780 xfs_btree_log_ptrs(cur, rbp, 1, rrecs);
2781
2782 /* Stash the keys of the new block for later insertion. */
2783 xfs_btree_get_node_keys(cur, right, key);
2784 } else {
2785 /* It's a leaf. Move records. */
2786 union xfs_btree_rec *lrp; /* left record pointer */
2787 union xfs_btree_rec *rrp; /* right record pointer */
2788
2789 lrp = xfs_btree_rec_addr(cur, src_index, left);
2790 rrp = xfs_btree_rec_addr(cur, 1, right);
2791
2792 /* Copy records to the new block. */
2793 xfs_btree_copy_recs(cur, rrp, lrp, rrecs);
2794 xfs_btree_log_recs(cur, rbp, 1, rrecs);
2795
2796 /* Stash the keys of the new block for later insertion. */
2797 xfs_btree_get_leaf_keys(cur, right, key);
2798 }
2799
2800 /*
2801 * Find the left block number by looking in the buffer.
2802 * Adjust sibling pointers.
2803 */
2804 xfs_btree_get_sibling(cur, left, &rrptr, XFS_BB_RIGHTSIB);
2805 xfs_btree_set_sibling(cur, right, &rrptr, XFS_BB_RIGHTSIB);
2806 xfs_btree_set_sibling(cur, right, &lptr, XFS_BB_LEFTSIB);
2807 xfs_btree_set_sibling(cur, left, &rptr, XFS_BB_RIGHTSIB);
2808
2809 xfs_btree_log_block(cur, rbp, XFS_BB_ALL_BITS);
2810 xfs_btree_log_block(cur, lbp, XFS_BB_NUMRECS | XFS_BB_RIGHTSIB);
2811
2812 /*
2813 * If there's a block to the new block's right, make that block
2814 * point back to right instead of to left.
2815 */
2816 if (!xfs_btree_ptr_is_null(cur, &rrptr)) {
2817 error = xfs_btree_read_buf_block(cur, &rrptr,
2818 0, &rrblock, &rrbp);
2819 if (error)
2820 goto error0;
2821 xfs_btree_set_sibling(cur, rrblock, &rptr, XFS_BB_LEFTSIB);
2822 xfs_btree_log_block(cur, rrbp, XFS_BB_LEFTSIB);
2823 }
2824
2825 /* Update the parent high keys of the left block, if needed. */
2826 if (cur->bc_flags & XFS_BTREE_OVERLAPPING) {
2827 error = xfs_btree_update_keys(cur, level);
2828 if (error)
2829 goto error0;
2830 }
2831
2832 /*
2833 * If the cursor is really in the right block, move it there.
2834 * If it's just pointing past the last entry in left, then we'll
2835 * insert there, so don't change anything in that case.
2836 */
2837 if (cur->bc_levels[level].ptr > lrecs + 1) {
2838 xfs_btree_setbuf(cur, level, rbp);
2839 cur->bc_levels[level].ptr -= lrecs;
2840 }
2841 /*
2842 * If there are more levels, we'll need another cursor which refers
2843 * the right block, no matter where this cursor was.
2844 */
2845 if (level + 1 < cur->bc_nlevels) {
2846 error = xfs_btree_dup_cursor(cur, curp);
2847 if (error)
2848 goto error0;
2849 (*curp)->bc_levels[level + 1].ptr++;
2850 }
2851 *ptrp = rptr;
2852 *stat = 1;
2853 return 0;
2854out0:
2855 *stat = 0;
2856 return 0;
2857
2858error0:
2859 return error;
2860}
2861
2862#ifdef __KERNEL__
2863struct xfs_btree_split_args {
2864 struct xfs_btree_cur *cur;
2865 int level;
2866 union xfs_btree_ptr *ptrp;
2867 union xfs_btree_key *key;
2868 struct xfs_btree_cur **curp;
2869 int *stat; /* success/failure */
2870 int result;
2871 bool kswapd; /* allocation in kswapd context */
2872 struct completion *done;
2873 struct work_struct work;
2874};
2875
2876/*
2877 * Stack switching interfaces for allocation
2878 */
2879static void
2880xfs_btree_split_worker(
2881 struct work_struct *work)
2882{
2883 struct xfs_btree_split_args *args = container_of(work,
2884 struct xfs_btree_split_args, work);
2885 unsigned long pflags;
2886 unsigned long new_pflags = 0;
2887
2888 /*
2889 * we are in a transaction context here, but may also be doing work
2890 * in kswapd context, and hence we may need to inherit that state
2891 * temporarily to ensure that we don't block waiting for memory reclaim
2892 * in any way.
2893 */
2894 if (args->kswapd)
2895 new_pflags |= PF_MEMALLOC | PF_KSWAPD;
2896
2897 current_set_flags_nested(&pflags, new_pflags);
2898 xfs_trans_set_context(args->cur->bc_tp);
2899
2900 args->result = __xfs_btree_split(args->cur, args->level, args->ptrp,
2901 args->key, args->curp, args->stat);
2902
2903 xfs_trans_clear_context(args->cur->bc_tp);
2904 current_restore_flags_nested(&pflags, new_pflags);
2905
2906 /*
2907 * Do not access args after complete() has run here. We don't own args
2908 * and the owner may run and free args before we return here.
2909 */
2910 complete(args->done);
2911
2912}
2913
2914/*
2915 * BMBT split requests often come in with little stack to work on so we push
2916 * them off to a worker thread so there is lots of stack to use. For the other
2917 * btree types, just call directly to avoid the context switch overhead here.
2918 *
2919 * Care must be taken here - the work queue rescuer thread introduces potential
2920 * AGF <> worker queue deadlocks if the BMBT block allocation has to lock new
2921 * AGFs to allocate blocks. A task being run by the rescuer could attempt to
2922 * lock an AGF that is already locked by a task queued to run by the rescuer,
2923 * resulting in an ABBA deadlock as the rescuer cannot run the lock holder to
2924 * release it until the current thread it is running gains the lock.
2925 *
2926 * To avoid this issue, we only ever queue BMBT splits that don't have an AGF
2927 * already locked to allocate from. The only place that doesn't hold an AGF
2928 * locked is unwritten extent conversion at IO completion, but that has already
2929 * been offloaded to a worker thread and hence has no stack consumption issues
2930 * we have to worry about.
2931 */
2932STATIC int /* error */
2933xfs_btree_split(
2934 struct xfs_btree_cur *cur,
2935 int level,
2936 union xfs_btree_ptr *ptrp,
2937 union xfs_btree_key *key,
2938 struct xfs_btree_cur **curp,
2939 int *stat) /* success/failure */
2940{
2941 struct xfs_btree_split_args args;
2942 DECLARE_COMPLETION_ONSTACK(done);
2943
2944 if (cur->bc_btnum != XFS_BTNUM_BMAP ||
2945 cur->bc_tp->t_highest_agno == NULLAGNUMBER)
2946 return __xfs_btree_split(cur, level, ptrp, key, curp, stat);
2947
2948 args.cur = cur;
2949 args.level = level;
2950 args.ptrp = ptrp;
2951 args.key = key;
2952 args.curp = curp;
2953 args.stat = stat;
2954 args.done = &done;
2955 args.kswapd = current_is_kswapd();
2956 INIT_WORK_ONSTACK(&args.work, xfs_btree_split_worker);
2957 queue_work(xfs_alloc_wq, &args.work);
2958 wait_for_completion(&done);
2959 destroy_work_on_stack(&args.work);
2960 return args.result;
2961}
2962#else
2963#define xfs_btree_split __xfs_btree_split
2964#endif /* __KERNEL__ */
2965
2966
2967/*
2968 * Copy the old inode root contents into a real block and make the
2969 * broot point to it.
2970 */
2971int /* error */
2972xfs_btree_new_iroot(
2973 struct xfs_btree_cur *cur, /* btree cursor */
2974 int *logflags, /* logging flags for inode */
2975 int *stat) /* return status - 0 fail */
2976{
2977 struct xfs_buf *cbp; /* buffer for cblock */
2978 struct xfs_btree_block *block; /* btree block */
2979 struct xfs_btree_block *cblock; /* child btree block */
2980 union xfs_btree_key *ckp; /* child key pointer */
2981 union xfs_btree_ptr *cpp; /* child ptr pointer */
2982 union xfs_btree_key *kp; /* pointer to btree key */
2983 union xfs_btree_ptr *pp; /* pointer to block addr */
2984 union xfs_btree_ptr nptr; /* new block addr */
2985 int level; /* btree level */
2986 int error; /* error return code */
2987 int i; /* loop counter */
2988
2989 XFS_BTREE_STATS_INC(cur, newroot);
2990
2991 ASSERT(cur->bc_flags & XFS_BTREE_ROOT_IN_INODE);
2992
2993 level = cur->bc_nlevels - 1;
2994
2995 block = xfs_btree_get_iroot(cur);
2996 pp = xfs_btree_ptr_addr(cur, 1, block);
2997
2998 /* Allocate the new block. If we can't do it, we're toast. Give up. */
2999 error = cur->bc_ops->alloc_block(cur, pp, &nptr, stat);
3000 if (error)
3001 goto error0;
3002 if (*stat == 0)
3003 return 0;
3004
3005 XFS_BTREE_STATS_INC(cur, alloc);
3006
3007 /* Copy the root into a real block. */
3008 error = xfs_btree_get_buf_block(cur, &nptr, &cblock, &cbp);
3009 if (error)
3010 goto error0;
3011
3012 /*
3013 * we can't just memcpy() the root in for CRC enabled btree blocks.
3014 * In that case have to also ensure the blkno remains correct
3015 */
3016 memcpy(cblock, block, xfs_btree_block_len(cur));
3017 if (cur->bc_flags & XFS_BTREE_CRC_BLOCKS) {
3018 __be64 bno = cpu_to_be64(xfs_buf_daddr(cbp));
3019 if (cur->bc_flags & XFS_BTREE_LONG_PTRS)
3020 cblock->bb_u.l.bb_blkno = bno;
3021 else
3022 cblock->bb_u.s.bb_blkno = bno;
3023 }
3024
3025 be16_add_cpu(&block->bb_level, 1);
3026 xfs_btree_set_numrecs(block, 1);
3027 cur->bc_nlevels++;
3028 ASSERT(cur->bc_nlevels <= cur->bc_maxlevels);
3029 cur->bc_levels[level + 1].ptr = 1;
3030
3031 kp = xfs_btree_key_addr(cur, 1, block);
3032 ckp = xfs_btree_key_addr(cur, 1, cblock);
3033 xfs_btree_copy_keys(cur, ckp, kp, xfs_btree_get_numrecs(cblock));
3034
3035 cpp = xfs_btree_ptr_addr(cur, 1, cblock);
3036 for (i = 0; i < be16_to_cpu(cblock->bb_numrecs); i++) {
3037 error = xfs_btree_debug_check_ptr(cur, pp, i, level);
3038 if (error)
3039 goto error0;
3040 }
3041
3042 xfs_btree_copy_ptrs(cur, cpp, pp, xfs_btree_get_numrecs(cblock));
3043
3044 error = xfs_btree_debug_check_ptr(cur, &nptr, 0, level);
3045 if (error)
3046 goto error0;
3047
3048 xfs_btree_copy_ptrs(cur, pp, &nptr, 1);
3049
3050 xfs_iroot_realloc(cur->bc_ino.ip,
3051 1 - xfs_btree_get_numrecs(cblock),
3052 cur->bc_ino.whichfork);
3053
3054 xfs_btree_setbuf(cur, level, cbp);
3055
3056 /*
3057 * Do all this logging at the end so that
3058 * the root is at the right level.
3059 */
3060 xfs_btree_log_block(cur, cbp, XFS_BB_ALL_BITS);
3061 xfs_btree_log_keys(cur, cbp, 1, be16_to_cpu(cblock->bb_numrecs));
3062 xfs_btree_log_ptrs(cur, cbp, 1, be16_to_cpu(cblock->bb_numrecs));
3063
3064 *logflags |=
3065 XFS_ILOG_CORE | xfs_ilog_fbroot(cur->bc_ino.whichfork);
3066 *stat = 1;
3067 return 0;
3068error0:
3069 return error;
3070}
3071
3072/*
3073 * Allocate a new root block, fill it in.
3074 */
3075STATIC int /* error */
3076xfs_btree_new_root(
3077 struct xfs_btree_cur *cur, /* btree cursor */
3078 int *stat) /* success/failure */
3079{
3080 struct xfs_btree_block *block; /* one half of the old root block */
3081 struct xfs_buf *bp; /* buffer containing block */
3082 int error; /* error return value */
3083 struct xfs_buf *lbp; /* left buffer pointer */
3084 struct xfs_btree_block *left; /* left btree block */
3085 struct xfs_buf *nbp; /* new (root) buffer */
3086 struct xfs_btree_block *new; /* new (root) btree block */
3087 int nptr; /* new value for key index, 1 or 2 */
3088 struct xfs_buf *rbp; /* right buffer pointer */
3089 struct xfs_btree_block *right; /* right btree block */
3090 union xfs_btree_ptr rptr;
3091 union xfs_btree_ptr lptr;
3092
3093 XFS_BTREE_STATS_INC(cur, newroot);
3094
3095 /* initialise our start point from the cursor */
3096 cur->bc_ops->init_ptr_from_cur(cur, &rptr);
3097
3098 /* Allocate the new block. If we can't do it, we're toast. Give up. */
3099 error = cur->bc_ops->alloc_block(cur, &rptr, &lptr, stat);
3100 if (error)
3101 goto error0;
3102 if (*stat == 0)
3103 goto out0;
3104 XFS_BTREE_STATS_INC(cur, alloc);
3105
3106 /* Set up the new block. */
3107 error = xfs_btree_get_buf_block(cur, &lptr, &new, &nbp);
3108 if (error)
3109 goto error0;
3110
3111 /* Set the root in the holding structure increasing the level by 1. */
3112 cur->bc_ops->set_root(cur, &lptr, 1);
3113
3114 /*
3115 * At the previous root level there are now two blocks: the old root,
3116 * and the new block generated when it was split. We don't know which
3117 * one the cursor is pointing at, so we set up variables "left" and
3118 * "right" for each case.
3119 */
3120 block = xfs_btree_get_block(cur, cur->bc_nlevels - 1, &bp);
3121
3122#ifdef DEBUG
3123 error = xfs_btree_check_block(cur, block, cur->bc_nlevels - 1, bp);
3124 if (error)
3125 goto error0;
3126#endif
3127
3128 xfs_btree_get_sibling(cur, block, &rptr, XFS_BB_RIGHTSIB);
3129 if (!xfs_btree_ptr_is_null(cur, &rptr)) {
3130 /* Our block is left, pick up the right block. */
3131 lbp = bp;
3132 xfs_btree_buf_to_ptr(cur, lbp, &lptr);
3133 left = block;
3134 error = xfs_btree_read_buf_block(cur, &rptr, 0, &right, &rbp);
3135 if (error)
3136 goto error0;
3137 bp = rbp;
3138 nptr = 1;
3139 } else {
3140 /* Our block is right, pick up the left block. */
3141 rbp = bp;
3142 xfs_btree_buf_to_ptr(cur, rbp, &rptr);
3143 right = block;
3144 xfs_btree_get_sibling(cur, right, &lptr, XFS_BB_LEFTSIB);
3145 error = xfs_btree_read_buf_block(cur, &lptr, 0, &left, &lbp);
3146 if (error)
3147 goto error0;
3148 bp = lbp;
3149 nptr = 2;
3150 }
3151
3152 /* Fill in the new block's btree header and log it. */
3153 xfs_btree_init_block_cur(cur, nbp, cur->bc_nlevels, 2);
3154 xfs_btree_log_block(cur, nbp, XFS_BB_ALL_BITS);
3155 ASSERT(!xfs_btree_ptr_is_null(cur, &lptr) &&
3156 !xfs_btree_ptr_is_null(cur, &rptr));
3157
3158 /* Fill in the key data in the new root. */
3159 if (xfs_btree_get_level(left) > 0) {
3160 /*
3161 * Get the keys for the left block's keys and put them directly
3162 * in the parent block. Do the same for the right block.
3163 */
3164 xfs_btree_get_node_keys(cur, left,
3165 xfs_btree_key_addr(cur, 1, new));
3166 xfs_btree_get_node_keys(cur, right,
3167 xfs_btree_key_addr(cur, 2, new));
3168 } else {
3169 /*
3170 * Get the keys for the left block's records and put them
3171 * directly in the parent block. Do the same for the right
3172 * block.
3173 */
3174 xfs_btree_get_leaf_keys(cur, left,
3175 xfs_btree_key_addr(cur, 1, new));
3176 xfs_btree_get_leaf_keys(cur, right,
3177 xfs_btree_key_addr(cur, 2, new));
3178 }
3179 xfs_btree_log_keys(cur, nbp, 1, 2);
3180
3181 /* Fill in the pointer data in the new root. */
3182 xfs_btree_copy_ptrs(cur,
3183 xfs_btree_ptr_addr(cur, 1, new), &lptr, 1);
3184 xfs_btree_copy_ptrs(cur,
3185 xfs_btree_ptr_addr(cur, 2, new), &rptr, 1);
3186 xfs_btree_log_ptrs(cur, nbp, 1, 2);
3187
3188 /* Fix up the cursor. */
3189 xfs_btree_setbuf(cur, cur->bc_nlevels, nbp);
3190 cur->bc_levels[cur->bc_nlevels].ptr = nptr;
3191 cur->bc_nlevels++;
3192 ASSERT(cur->bc_nlevels <= cur->bc_maxlevels);
3193 *stat = 1;
3194 return 0;
3195error0:
3196 return error;
3197out0:
3198 *stat = 0;
3199 return 0;
3200}
3201
3202STATIC int
3203xfs_btree_make_block_unfull(
3204 struct xfs_btree_cur *cur, /* btree cursor */
3205 int level, /* btree level */
3206 int numrecs,/* # of recs in block */
3207 int *oindex,/* old tree index */
3208 int *index, /* new tree index */
3209 union xfs_btree_ptr *nptr, /* new btree ptr */
3210 struct xfs_btree_cur **ncur, /* new btree cursor */
3211 union xfs_btree_key *key, /* key of new block */
3212 int *stat)
3213{
3214 int error = 0;
3215
3216 if ((cur->bc_flags & XFS_BTREE_ROOT_IN_INODE) &&
3217 level == cur->bc_nlevels - 1) {
3218 struct xfs_inode *ip = cur->bc_ino.ip;
3219
3220 if (numrecs < cur->bc_ops->get_dmaxrecs(cur, level)) {
3221 /* A root block that can be made bigger. */
3222 xfs_iroot_realloc(ip, 1, cur->bc_ino.whichfork);
3223 *stat = 1;
3224 } else {
3225 /* A root block that needs replacing */
3226 int logflags = 0;
3227
3228 error = xfs_btree_new_iroot(cur, &logflags, stat);
3229 if (error || *stat == 0)
3230 return error;
3231
3232 xfs_trans_log_inode(cur->bc_tp, ip, logflags);
3233 }
3234
3235 return 0;
3236 }
3237
3238 /* First, try shifting an entry to the right neighbor. */
3239 error = xfs_btree_rshift(cur, level, stat);
3240 if (error || *stat)
3241 return error;
3242
3243 /* Next, try shifting an entry to the left neighbor. */
3244 error = xfs_btree_lshift(cur, level, stat);
3245 if (error)
3246 return error;
3247
3248 if (*stat) {
3249 *oindex = *index = cur->bc_levels[level].ptr;
3250 return 0;
3251 }
3252
3253 /*
3254 * Next, try splitting the current block in half.
3255 *
3256 * If this works we have to re-set our variables because we
3257 * could be in a different block now.
3258 */
3259 error = xfs_btree_split(cur, level, nptr, key, ncur, stat);
3260 if (error || *stat == 0)
3261 return error;
3262
3263
3264 *index = cur->bc_levels[level].ptr;
3265 return 0;
3266}
3267
3268/*
3269 * Insert one record/level. Return information to the caller
3270 * allowing the next level up to proceed if necessary.
3271 */
3272STATIC int
3273xfs_btree_insrec(
3274 struct xfs_btree_cur *cur, /* btree cursor */
3275 int level, /* level to insert record at */
3276 union xfs_btree_ptr *ptrp, /* i/o: block number inserted */
3277 union xfs_btree_rec *rec, /* record to insert */
3278 union xfs_btree_key *key, /* i/o: block key for ptrp */
3279 struct xfs_btree_cur **curp, /* output: new cursor replacing cur */
3280 int *stat) /* success/failure */
3281{
3282 struct xfs_btree_block *block; /* btree block */
3283 struct xfs_buf *bp; /* buffer for block */
3284 union xfs_btree_ptr nptr; /* new block ptr */
3285 struct xfs_btree_cur *ncur = NULL; /* new btree cursor */
3286 union xfs_btree_key nkey; /* new block key */
3287 union xfs_btree_key *lkey;
3288 int optr; /* old key/record index */
3289 int ptr; /* key/record index */
3290 int numrecs;/* number of records */
3291 int error; /* error return value */
3292 int i;
3293 xfs_daddr_t old_bn;
3294
3295 ncur = NULL;
3296 lkey = &nkey;
3297
3298 /*
3299 * If we have an external root pointer, and we've made it to the
3300 * root level, allocate a new root block and we're done.
3301 */
3302 if (!(cur->bc_flags & XFS_BTREE_ROOT_IN_INODE) &&
3303 (level >= cur->bc_nlevels)) {
3304 error = xfs_btree_new_root(cur, stat);
3305 xfs_btree_set_ptr_null(cur, ptrp);
3306
3307 return error;
3308 }
3309
3310 /* If we're off the left edge, return failure. */
3311 ptr = cur->bc_levels[level].ptr;
3312 if (ptr == 0) {
3313 *stat = 0;
3314 return 0;
3315 }
3316
3317 optr = ptr;
3318
3319 XFS_BTREE_STATS_INC(cur, insrec);
3320
3321 /* Get pointers to the btree buffer and block. */
3322 block = xfs_btree_get_block(cur, level, &bp);
3323 old_bn = bp ? xfs_buf_daddr(bp) : XFS_BUF_DADDR_NULL;
3324 numrecs = xfs_btree_get_numrecs(block);
3325
3326#ifdef DEBUG
3327 error = xfs_btree_check_block(cur, block, level, bp);
3328 if (error)
3329 goto error0;
3330
3331 /* Check that the new entry is being inserted in the right place. */
3332 if (ptr <= numrecs) {
3333 if (level == 0) {
3334 ASSERT(cur->bc_ops->recs_inorder(cur, rec,
3335 xfs_btree_rec_addr(cur, ptr, block)));
3336 } else {
3337 ASSERT(cur->bc_ops->keys_inorder(cur, key,
3338 xfs_btree_key_addr(cur, ptr, block)));
3339 }
3340 }
3341#endif
3342
3343 /*
3344 * If the block is full, we can't insert the new entry until we
3345 * make the block un-full.
3346 */
3347 xfs_btree_set_ptr_null(cur, &nptr);
3348 if (numrecs == cur->bc_ops->get_maxrecs(cur, level)) {
3349 error = xfs_btree_make_block_unfull(cur, level, numrecs,
3350 &optr, &ptr, &nptr, &ncur, lkey, stat);
3351 if (error || *stat == 0)
3352 goto error0;
3353 }
3354
3355 /*
3356 * The current block may have changed if the block was
3357 * previously full and we have just made space in it.
3358 */
3359 block = xfs_btree_get_block(cur, level, &bp);
3360 numrecs = xfs_btree_get_numrecs(block);
3361
3362#ifdef DEBUG
3363 error = xfs_btree_check_block(cur, block, level, bp);
3364 if (error)
3365 goto error0;
3366#endif
3367
3368 /*
3369 * At this point we know there's room for our new entry in the block
3370 * we're pointing at.
3371 */
3372 XFS_BTREE_STATS_ADD(cur, moves, numrecs - ptr + 1);
3373
3374 if (level > 0) {
3375 /* It's a nonleaf. make a hole in the keys and ptrs */
3376 union xfs_btree_key *kp;
3377 union xfs_btree_ptr *pp;
3378
3379 kp = xfs_btree_key_addr(cur, ptr, block);
3380 pp = xfs_btree_ptr_addr(cur, ptr, block);
3381
3382 for (i = numrecs - ptr; i >= 0; i--) {
3383 error = xfs_btree_debug_check_ptr(cur, pp, i, level);
3384 if (error)
3385 goto error0;
3386 }
3387
3388 xfs_btree_shift_keys(cur, kp, 1, numrecs - ptr + 1);
3389 xfs_btree_shift_ptrs(cur, pp, 1, numrecs - ptr + 1);
3390
3391 error = xfs_btree_debug_check_ptr(cur, ptrp, 0, level);
3392 if (error)
3393 goto error0;
3394
3395 /* Now put the new data in, bump numrecs and log it. */
3396 xfs_btree_copy_keys(cur, kp, key, 1);
3397 xfs_btree_copy_ptrs(cur, pp, ptrp, 1);
3398 numrecs++;
3399 xfs_btree_set_numrecs(block, numrecs);
3400 xfs_btree_log_ptrs(cur, bp, ptr, numrecs);
3401 xfs_btree_log_keys(cur, bp, ptr, numrecs);
3402#ifdef DEBUG
3403 if (ptr < numrecs) {
3404 ASSERT(cur->bc_ops->keys_inorder(cur, kp,
3405 xfs_btree_key_addr(cur, ptr + 1, block)));
3406 }
3407#endif
3408 } else {
3409 /* It's a leaf. make a hole in the records */
3410 union xfs_btree_rec *rp;
3411
3412 rp = xfs_btree_rec_addr(cur, ptr, block);
3413
3414 xfs_btree_shift_recs(cur, rp, 1, numrecs - ptr + 1);
3415
3416 /* Now put the new data in, bump numrecs and log it. */
3417 xfs_btree_copy_recs(cur, rp, rec, 1);
3418 xfs_btree_set_numrecs(block, ++numrecs);
3419 xfs_btree_log_recs(cur, bp, ptr, numrecs);
3420#ifdef DEBUG
3421 if (ptr < numrecs) {
3422 ASSERT(cur->bc_ops->recs_inorder(cur, rp,
3423 xfs_btree_rec_addr(cur, ptr + 1, block)));
3424 }
3425#endif
3426 }
3427
3428 /* Log the new number of records in the btree header. */
3429 xfs_btree_log_block(cur, bp, XFS_BB_NUMRECS);
3430
3431 /*
3432 * If we just inserted into a new tree block, we have to
3433 * recalculate nkey here because nkey is out of date.
3434 *
3435 * Otherwise we're just updating an existing block (having shoved
3436 * some records into the new tree block), so use the regular key
3437 * update mechanism.
3438 */
3439 if (bp && xfs_buf_daddr(bp) != old_bn) {
3440 xfs_btree_get_keys(cur, block, lkey);
3441 } else if (xfs_btree_needs_key_update(cur, optr)) {
3442 error = xfs_btree_update_keys(cur, level);
3443 if (error)
3444 goto error0;
3445 }
3446
3447 /*
3448 * If we are tracking the last record in the tree and
3449 * we are at the far right edge of the tree, update it.
3450 */
3451 if (xfs_btree_is_lastrec(cur, block, level)) {
3452 cur->bc_ops->update_lastrec(cur, block, rec,
3453 ptr, LASTREC_INSREC);
3454 }
3455
3456 /*
3457 * Return the new block number, if any.
3458 * If there is one, give back a record value and a cursor too.
3459 */
3460 *ptrp = nptr;
3461 if (!xfs_btree_ptr_is_null(cur, &nptr)) {
3462 xfs_btree_copy_keys(cur, key, lkey, 1);
3463 *curp = ncur;
3464 }
3465
3466 *stat = 1;
3467 return 0;
3468
3469error0:
3470 if (ncur)
3471 xfs_btree_del_cursor(ncur, error);
3472 return error;
3473}
3474
3475/*
3476 * Insert the record at the point referenced by cur.
3477 *
3478 * A multi-level split of the tree on insert will invalidate the original
3479 * cursor. All callers of this function should assume that the cursor is
3480 * no longer valid and revalidate it.
3481 */
3482int
3483xfs_btree_insert(
3484 struct xfs_btree_cur *cur,
3485 int *stat)
3486{
3487 int error; /* error return value */
3488 int i; /* result value, 0 for failure */
3489 int level; /* current level number in btree */
3490 union xfs_btree_ptr nptr; /* new block number (split result) */
3491 struct xfs_btree_cur *ncur; /* new cursor (split result) */
3492 struct xfs_btree_cur *pcur; /* previous level's cursor */
3493 union xfs_btree_key bkey; /* key of block to insert */
3494 union xfs_btree_key *key;
3495 union xfs_btree_rec rec; /* record to insert */
3496
3497 level = 0;
3498 ncur = NULL;
3499 pcur = cur;
3500 key = &bkey;
3501
3502 xfs_btree_set_ptr_null(cur, &nptr);
3503
3504 /* Make a key out of the record data to be inserted, and save it. */
3505 cur->bc_ops->init_rec_from_cur(cur, &rec);
3506 cur->bc_ops->init_key_from_rec(key, &rec);
3507
3508 /*
3509 * Loop going up the tree, starting at the leaf level.
3510 * Stop when we don't get a split block, that must mean that
3511 * the insert is finished with this level.
3512 */
3513 do {
3514 /*
3515 * Insert nrec/nptr into this level of the tree.
3516 * Note if we fail, nptr will be null.
3517 */
3518 error = xfs_btree_insrec(pcur, level, &nptr, &rec, key,
3519 &ncur, &i);
3520 if (error) {
3521 if (pcur != cur)
3522 xfs_btree_del_cursor(pcur, XFS_BTREE_ERROR);
3523 goto error0;
3524 }
3525
3526 if (XFS_IS_CORRUPT(cur->bc_mp, i != 1)) {
3527 error = -EFSCORRUPTED;
3528 goto error0;
3529 }
3530 level++;
3531
3532 /*
3533 * See if the cursor we just used is trash.
3534 * Can't trash the caller's cursor, but otherwise we should
3535 * if ncur is a new cursor or we're about to be done.
3536 */
3537 if (pcur != cur &&
3538 (ncur || xfs_btree_ptr_is_null(cur, &nptr))) {
3539 /* Save the state from the cursor before we trash it */
3540 if (cur->bc_ops->update_cursor)
3541 cur->bc_ops->update_cursor(pcur, cur);
3542 cur->bc_nlevels = pcur->bc_nlevels;
3543 xfs_btree_del_cursor(pcur, XFS_BTREE_NOERROR);
3544 }
3545 /* If we got a new cursor, switch to it. */
3546 if (ncur) {
3547 pcur = ncur;
3548 ncur = NULL;
3549 }
3550 } while (!xfs_btree_ptr_is_null(cur, &nptr));
3551
3552 *stat = i;
3553 return 0;
3554error0:
3555 return error;
3556}
3557
3558/*
3559 * Try to merge a non-leaf block back into the inode root.
3560 *
3561 * Note: the killroot names comes from the fact that we're effectively
3562 * killing the old root block. But because we can't just delete the
3563 * inode we have to copy the single block it was pointing to into the
3564 * inode.
3565 */
3566STATIC int
3567xfs_btree_kill_iroot(
3568 struct xfs_btree_cur *cur)
3569{
3570 int whichfork = cur->bc_ino.whichfork;
3571 struct xfs_inode *ip = cur->bc_ino.ip;
3572 struct xfs_ifork *ifp = xfs_ifork_ptr(ip, whichfork);
3573 struct xfs_btree_block *block;
3574 struct xfs_btree_block *cblock;
3575 union xfs_btree_key *kp;
3576 union xfs_btree_key *ckp;
3577 union xfs_btree_ptr *pp;
3578 union xfs_btree_ptr *cpp;
3579 struct xfs_buf *cbp;
3580 int level;
3581 int index;
3582 int numrecs;
3583 int error;
3584#ifdef DEBUG
3585 union xfs_btree_ptr ptr;
3586#endif
3587 int i;
3588
3589 ASSERT(cur->bc_flags & XFS_BTREE_ROOT_IN_INODE);
3590 ASSERT(cur->bc_nlevels > 1);
3591
3592 /*
3593 * Don't deal with the root block needs to be a leaf case.
3594 * We're just going to turn the thing back into extents anyway.
3595 */
3596 level = cur->bc_nlevels - 1;
3597 if (level == 1)
3598 goto out0;
3599
3600 /*
3601 * Give up if the root has multiple children.
3602 */
3603 block = xfs_btree_get_iroot(cur);
3604 if (xfs_btree_get_numrecs(block) != 1)
3605 goto out0;
3606
3607 cblock = xfs_btree_get_block(cur, level - 1, &cbp);
3608 numrecs = xfs_btree_get_numrecs(cblock);
3609
3610 /*
3611 * Only do this if the next level will fit.
3612 * Then the data must be copied up to the inode,
3613 * instead of freeing the root you free the next level.
3614 */
3615 if (numrecs > cur->bc_ops->get_dmaxrecs(cur, level))
3616 goto out0;
3617
3618 XFS_BTREE_STATS_INC(cur, killroot);
3619
3620#ifdef DEBUG
3621 xfs_btree_get_sibling(cur, block, &ptr, XFS_BB_LEFTSIB);
3622 ASSERT(xfs_btree_ptr_is_null(cur, &ptr));
3623 xfs_btree_get_sibling(cur, block, &ptr, XFS_BB_RIGHTSIB);
3624 ASSERT(xfs_btree_ptr_is_null(cur, &ptr));
3625#endif
3626
3627 index = numrecs - cur->bc_ops->get_maxrecs(cur, level);
3628 if (index) {
3629 xfs_iroot_realloc(cur->bc_ino.ip, index,
3630 cur->bc_ino.whichfork);
3631 block = ifp->if_broot;
3632 }
3633
3634 be16_add_cpu(&block->bb_numrecs, index);
3635 ASSERT(block->bb_numrecs == cblock->bb_numrecs);
3636
3637 kp = xfs_btree_key_addr(cur, 1, block);
3638 ckp = xfs_btree_key_addr(cur, 1, cblock);
3639 xfs_btree_copy_keys(cur, kp, ckp, numrecs);
3640
3641 pp = xfs_btree_ptr_addr(cur, 1, block);
3642 cpp = xfs_btree_ptr_addr(cur, 1, cblock);
3643
3644 for (i = 0; i < numrecs; i++) {
3645 error = xfs_btree_debug_check_ptr(cur, cpp, i, level - 1);
3646 if (error)
3647 return error;
3648 }
3649
3650 xfs_btree_copy_ptrs(cur, pp, cpp, numrecs);
3651
3652 error = xfs_btree_free_block(cur, cbp);
3653 if (error)
3654 return error;
3655
3656 cur->bc_levels[level - 1].bp = NULL;
3657 be16_add_cpu(&block->bb_level, -1);
3658 xfs_trans_log_inode(cur->bc_tp, ip,
3659 XFS_ILOG_CORE | xfs_ilog_fbroot(cur->bc_ino.whichfork));
3660 cur->bc_nlevels--;
3661out0:
3662 return 0;
3663}
3664
3665/*
3666 * Kill the current root node, and replace it with it's only child node.
3667 */
3668STATIC int
3669xfs_btree_kill_root(
3670 struct xfs_btree_cur *cur,
3671 struct xfs_buf *bp,
3672 int level,
3673 union xfs_btree_ptr *newroot)
3674{
3675 int error;
3676
3677 XFS_BTREE_STATS_INC(cur, killroot);
3678
3679 /*
3680 * Update the root pointer, decreasing the level by 1 and then
3681 * free the old root.
3682 */
3683 cur->bc_ops->set_root(cur, newroot, -1);
3684
3685 error = xfs_btree_free_block(cur, bp);
3686 if (error)
3687 return error;
3688
3689 cur->bc_levels[level].bp = NULL;
3690 cur->bc_levels[level].ra = 0;
3691 cur->bc_nlevels--;
3692
3693 return 0;
3694}
3695
3696STATIC int
3697xfs_btree_dec_cursor(
3698 struct xfs_btree_cur *cur,
3699 int level,
3700 int *stat)
3701{
3702 int error;
3703 int i;
3704
3705 if (level > 0) {
3706 error = xfs_btree_decrement(cur, level, &i);
3707 if (error)
3708 return error;
3709 }
3710
3711 *stat = 1;
3712 return 0;
3713}
3714
3715/*
3716 * Single level of the btree record deletion routine.
3717 * Delete record pointed to by cur/level.
3718 * Remove the record from its block then rebalance the tree.
3719 * Return 0 for error, 1 for done, 2 to go on to the next level.
3720 */
3721STATIC int /* error */
3722xfs_btree_delrec(
3723 struct xfs_btree_cur *cur, /* btree cursor */
3724 int level, /* level removing record from */
3725 int *stat) /* fail/done/go-on */
3726{
3727 struct xfs_btree_block *block; /* btree block */
3728 union xfs_btree_ptr cptr; /* current block ptr */
3729 struct xfs_buf *bp; /* buffer for block */
3730 int error; /* error return value */
3731 int i; /* loop counter */
3732 union xfs_btree_ptr lptr; /* left sibling block ptr */
3733 struct xfs_buf *lbp; /* left buffer pointer */
3734 struct xfs_btree_block *left; /* left btree block */
3735 int lrecs = 0; /* left record count */
3736 int ptr; /* key/record index */
3737 union xfs_btree_ptr rptr; /* right sibling block ptr */
3738 struct xfs_buf *rbp; /* right buffer pointer */
3739 struct xfs_btree_block *right; /* right btree block */
3740 struct xfs_btree_block *rrblock; /* right-right btree block */
3741 struct xfs_buf *rrbp; /* right-right buffer pointer */
3742 int rrecs = 0; /* right record count */
3743 struct xfs_btree_cur *tcur; /* temporary btree cursor */
3744 int numrecs; /* temporary numrec count */
3745
3746 tcur = NULL;
3747
3748 /* Get the index of the entry being deleted, check for nothing there. */
3749 ptr = cur->bc_levels[level].ptr;
3750 if (ptr == 0) {
3751 *stat = 0;
3752 return 0;
3753 }
3754
3755 /* Get the buffer & block containing the record or key/ptr. */
3756 block = xfs_btree_get_block(cur, level, &bp);
3757 numrecs = xfs_btree_get_numrecs(block);
3758
3759#ifdef DEBUG
3760 error = xfs_btree_check_block(cur, block, level, bp);
3761 if (error)
3762 goto error0;
3763#endif
3764
3765 /* Fail if we're off the end of the block. */
3766 if (ptr > numrecs) {
3767 *stat = 0;
3768 return 0;
3769 }
3770
3771 XFS_BTREE_STATS_INC(cur, delrec);
3772 XFS_BTREE_STATS_ADD(cur, moves, numrecs - ptr);
3773
3774 /* Excise the entries being deleted. */
3775 if (level > 0) {
3776 /* It's a nonleaf. operate on keys and ptrs */
3777 union xfs_btree_key *lkp;
3778 union xfs_btree_ptr *lpp;
3779
3780 lkp = xfs_btree_key_addr(cur, ptr + 1, block);
3781 lpp = xfs_btree_ptr_addr(cur, ptr + 1, block);
3782
3783 for (i = 0; i < numrecs - ptr; i++) {
3784 error = xfs_btree_debug_check_ptr(cur, lpp, i, level);
3785 if (error)
3786 goto error0;
3787 }
3788
3789 if (ptr < numrecs) {
3790 xfs_btree_shift_keys(cur, lkp, -1, numrecs - ptr);
3791 xfs_btree_shift_ptrs(cur, lpp, -1, numrecs - ptr);
3792 xfs_btree_log_keys(cur, bp, ptr, numrecs - 1);
3793 xfs_btree_log_ptrs(cur, bp, ptr, numrecs - 1);
3794 }
3795 } else {
3796 /* It's a leaf. operate on records */
3797 if (ptr < numrecs) {
3798 xfs_btree_shift_recs(cur,
3799 xfs_btree_rec_addr(cur, ptr + 1, block),
3800 -1, numrecs - ptr);
3801 xfs_btree_log_recs(cur, bp, ptr, numrecs - 1);
3802 }
3803 }
3804
3805 /*
3806 * Decrement and log the number of entries in the block.
3807 */
3808 xfs_btree_set_numrecs(block, --numrecs);
3809 xfs_btree_log_block(cur, bp, XFS_BB_NUMRECS);
3810
3811 /*
3812 * If we are tracking the last record in the tree and
3813 * we are at the far right edge of the tree, update it.
3814 */
3815 if (xfs_btree_is_lastrec(cur, block, level)) {
3816 cur->bc_ops->update_lastrec(cur, block, NULL,
3817 ptr, LASTREC_DELREC);
3818 }
3819
3820 /*
3821 * We're at the root level. First, shrink the root block in-memory.
3822 * Try to get rid of the next level down. If we can't then there's
3823 * nothing left to do.
3824 */
3825 if (level == cur->bc_nlevels - 1) {
3826 if (cur->bc_flags & XFS_BTREE_ROOT_IN_INODE) {
3827 xfs_iroot_realloc(cur->bc_ino.ip, -1,
3828 cur->bc_ino.whichfork);
3829
3830 error = xfs_btree_kill_iroot(cur);
3831 if (error)
3832 goto error0;
3833
3834 error = xfs_btree_dec_cursor(cur, level, stat);
3835 if (error)
3836 goto error0;
3837 *stat = 1;
3838 return 0;
3839 }
3840
3841 /*
3842 * If this is the root level, and there's only one entry left,
3843 * and it's NOT the leaf level, then we can get rid of this
3844 * level.
3845 */
3846 if (numrecs == 1 && level > 0) {
3847 union xfs_btree_ptr *pp;
3848 /*
3849 * pp is still set to the first pointer in the block.
3850 * Make it the new root of the btree.
3851 */
3852 pp = xfs_btree_ptr_addr(cur, 1, block);
3853 error = xfs_btree_kill_root(cur, bp, level, pp);
3854 if (error)
3855 goto error0;
3856 } else if (level > 0) {
3857 error = xfs_btree_dec_cursor(cur, level, stat);
3858 if (error)
3859 goto error0;
3860 }
3861 *stat = 1;
3862 return 0;
3863 }
3864
3865 /*
3866 * If we deleted the leftmost entry in the block, update the
3867 * key values above us in the tree.
3868 */
3869 if (xfs_btree_needs_key_update(cur, ptr)) {
3870 error = xfs_btree_update_keys(cur, level);
3871 if (error)
3872 goto error0;
3873 }
3874
3875 /*
3876 * If the number of records remaining in the block is at least
3877 * the minimum, we're done.
3878 */
3879 if (numrecs >= cur->bc_ops->get_minrecs(cur, level)) {
3880 error = xfs_btree_dec_cursor(cur, level, stat);
3881 if (error)
3882 goto error0;
3883 return 0;
3884 }
3885
3886 /*
3887 * Otherwise, we have to move some records around to keep the
3888 * tree balanced. Look at the left and right sibling blocks to
3889 * see if we can re-balance by moving only one record.
3890 */
3891 xfs_btree_get_sibling(cur, block, &rptr, XFS_BB_RIGHTSIB);
3892 xfs_btree_get_sibling(cur, block, &lptr, XFS_BB_LEFTSIB);
3893
3894 if (cur->bc_flags & XFS_BTREE_ROOT_IN_INODE) {
3895 /*
3896 * One child of root, need to get a chance to copy its contents
3897 * into the root and delete it. Can't go up to next level,
3898 * there's nothing to delete there.
3899 */
3900 if (xfs_btree_ptr_is_null(cur, &rptr) &&
3901 xfs_btree_ptr_is_null(cur, &lptr) &&
3902 level == cur->bc_nlevels - 2) {
3903 error = xfs_btree_kill_iroot(cur);
3904 if (!error)
3905 error = xfs_btree_dec_cursor(cur, level, stat);
3906 if (error)
3907 goto error0;
3908 return 0;
3909 }
3910 }
3911
3912 ASSERT(!xfs_btree_ptr_is_null(cur, &rptr) ||
3913 !xfs_btree_ptr_is_null(cur, &lptr));
3914
3915 /*
3916 * Duplicate the cursor so our btree manipulations here won't
3917 * disrupt the next level up.
3918 */
3919 error = xfs_btree_dup_cursor(cur, &tcur);
3920 if (error)
3921 goto error0;
3922
3923 /*
3924 * If there's a right sibling, see if it's ok to shift an entry
3925 * out of it.
3926 */
3927 if (!xfs_btree_ptr_is_null(cur, &rptr)) {
3928 /*
3929 * Move the temp cursor to the last entry in the next block.
3930 * Actually any entry but the first would suffice.
3931 */
3932 i = xfs_btree_lastrec(tcur, level);
3933 if (XFS_IS_CORRUPT(cur->bc_mp, i != 1)) {
3934 error = -EFSCORRUPTED;
3935 goto error0;
3936 }
3937
3938 error = xfs_btree_increment(tcur, level, &i);
3939 if (error)
3940 goto error0;
3941 if (XFS_IS_CORRUPT(cur->bc_mp, i != 1)) {
3942 error = -EFSCORRUPTED;
3943 goto error0;
3944 }
3945
3946 i = xfs_btree_lastrec(tcur, level);
3947 if (XFS_IS_CORRUPT(cur->bc_mp, i != 1)) {
3948 error = -EFSCORRUPTED;
3949 goto error0;
3950 }
3951
3952 /* Grab a pointer to the block. */
3953 right = xfs_btree_get_block(tcur, level, &rbp);
3954#ifdef DEBUG
3955 error = xfs_btree_check_block(tcur, right, level, rbp);
3956 if (error)
3957 goto error0;
3958#endif
3959 /* Grab the current block number, for future use. */
3960 xfs_btree_get_sibling(tcur, right, &cptr, XFS_BB_LEFTSIB);
3961
3962 /*
3963 * If right block is full enough so that removing one entry
3964 * won't make it too empty, and left-shifting an entry out
3965 * of right to us works, we're done.
3966 */
3967 if (xfs_btree_get_numrecs(right) - 1 >=
3968 cur->bc_ops->get_minrecs(tcur, level)) {
3969 error = xfs_btree_lshift(tcur, level, &i);
3970 if (error)
3971 goto error0;
3972 if (i) {
3973 ASSERT(xfs_btree_get_numrecs(block) >=
3974 cur->bc_ops->get_minrecs(tcur, level));
3975
3976 xfs_btree_del_cursor(tcur, XFS_BTREE_NOERROR);
3977 tcur = NULL;
3978
3979 error = xfs_btree_dec_cursor(cur, level, stat);
3980 if (error)
3981 goto error0;
3982 return 0;
3983 }
3984 }
3985
3986 /*
3987 * Otherwise, grab the number of records in right for
3988 * future reference, and fix up the temp cursor to point
3989 * to our block again (last record).
3990 */
3991 rrecs = xfs_btree_get_numrecs(right);
3992 if (!xfs_btree_ptr_is_null(cur, &lptr)) {
3993 i = xfs_btree_firstrec(tcur, level);
3994 if (XFS_IS_CORRUPT(cur->bc_mp, i != 1)) {
3995 error = -EFSCORRUPTED;
3996 goto error0;
3997 }
3998
3999 error = xfs_btree_decrement(tcur, level, &i);
4000 if (error)
4001 goto error0;
4002 if (XFS_IS_CORRUPT(cur->bc_mp, i != 1)) {
4003 error = -EFSCORRUPTED;
4004 goto error0;
4005 }
4006 }
4007 }
4008
4009 /*
4010 * If there's a left sibling, see if it's ok to shift an entry
4011 * out of it.
4012 */
4013 if (!xfs_btree_ptr_is_null(cur, &lptr)) {
4014 /*
4015 * Move the temp cursor to the first entry in the
4016 * previous block.
4017 */
4018 i = xfs_btree_firstrec(tcur, level);
4019 if (XFS_IS_CORRUPT(cur->bc_mp, i != 1)) {
4020 error = -EFSCORRUPTED;
4021 goto error0;
4022 }
4023
4024 error = xfs_btree_decrement(tcur, level, &i);
4025 if (error)
4026 goto error0;
4027 i = xfs_btree_firstrec(tcur, level);
4028 if (XFS_IS_CORRUPT(cur->bc_mp, i != 1)) {
4029 error = -EFSCORRUPTED;
4030 goto error0;
4031 }
4032
4033 /* Grab a pointer to the block. */
4034 left = xfs_btree_get_block(tcur, level, &lbp);
4035#ifdef DEBUG
4036 error = xfs_btree_check_block(cur, left, level, lbp);
4037 if (error)
4038 goto error0;
4039#endif
4040 /* Grab the current block number, for future use. */
4041 xfs_btree_get_sibling(tcur, left, &cptr, XFS_BB_RIGHTSIB);
4042
4043 /*
4044 * If left block is full enough so that removing one entry
4045 * won't make it too empty, and right-shifting an entry out
4046 * of left to us works, we're done.
4047 */
4048 if (xfs_btree_get_numrecs(left) - 1 >=
4049 cur->bc_ops->get_minrecs(tcur, level)) {
4050 error = xfs_btree_rshift(tcur, level, &i);
4051 if (error)
4052 goto error0;
4053 if (i) {
4054 ASSERT(xfs_btree_get_numrecs(block) >=
4055 cur->bc_ops->get_minrecs(tcur, level));
4056 xfs_btree_del_cursor(tcur, XFS_BTREE_NOERROR);
4057 tcur = NULL;
4058 if (level == 0)
4059 cur->bc_levels[0].ptr++;
4060
4061 *stat = 1;
4062 return 0;
4063 }
4064 }
4065
4066 /*
4067 * Otherwise, grab the number of records in right for
4068 * future reference.
4069 */
4070 lrecs = xfs_btree_get_numrecs(left);
4071 }
4072
4073 /* Delete the temp cursor, we're done with it. */
4074 xfs_btree_del_cursor(tcur, XFS_BTREE_NOERROR);
4075 tcur = NULL;
4076
4077 /* If here, we need to do a join to keep the tree balanced. */
4078 ASSERT(!xfs_btree_ptr_is_null(cur, &cptr));
4079
4080 if (!xfs_btree_ptr_is_null(cur, &lptr) &&
4081 lrecs + xfs_btree_get_numrecs(block) <=
4082 cur->bc_ops->get_maxrecs(cur, level)) {
4083 /*
4084 * Set "right" to be the starting block,
4085 * "left" to be the left neighbor.
4086 */
4087 rptr = cptr;
4088 right = block;
4089 rbp = bp;
4090 error = xfs_btree_read_buf_block(cur, &lptr, 0, &left, &lbp);
4091 if (error)
4092 goto error0;
4093
4094 /*
4095 * If that won't work, see if we can join with the right neighbor block.
4096 */
4097 } else if (!xfs_btree_ptr_is_null(cur, &rptr) &&
4098 rrecs + xfs_btree_get_numrecs(block) <=
4099 cur->bc_ops->get_maxrecs(cur, level)) {
4100 /*
4101 * Set "left" to be the starting block,
4102 * "right" to be the right neighbor.
4103 */
4104 lptr = cptr;
4105 left = block;
4106 lbp = bp;
4107 error = xfs_btree_read_buf_block(cur, &rptr, 0, &right, &rbp);
4108 if (error)
4109 goto error0;
4110
4111 /*
4112 * Otherwise, we can't fix the imbalance.
4113 * Just return. This is probably a logic error, but it's not fatal.
4114 */
4115 } else {
4116 error = xfs_btree_dec_cursor(cur, level, stat);
4117 if (error)
4118 goto error0;
4119 return 0;
4120 }
4121
4122 rrecs = xfs_btree_get_numrecs(right);
4123 lrecs = xfs_btree_get_numrecs(left);
4124
4125 /*
4126 * We're now going to join "left" and "right" by moving all the stuff
4127 * in "right" to "left" and deleting "right".
4128 */
4129 XFS_BTREE_STATS_ADD(cur, moves, rrecs);
4130 if (level > 0) {
4131 /* It's a non-leaf. Move keys and pointers. */
4132 union xfs_btree_key *lkp; /* left btree key */
4133 union xfs_btree_ptr *lpp; /* left address pointer */
4134 union xfs_btree_key *rkp; /* right btree key */
4135 union xfs_btree_ptr *rpp; /* right address pointer */
4136
4137 lkp = xfs_btree_key_addr(cur, lrecs + 1, left);
4138 lpp = xfs_btree_ptr_addr(cur, lrecs + 1, left);
4139 rkp = xfs_btree_key_addr(cur, 1, right);
4140 rpp = xfs_btree_ptr_addr(cur, 1, right);
4141
4142 for (i = 1; i < rrecs; i++) {
4143 error = xfs_btree_debug_check_ptr(cur, rpp, i, level);
4144 if (error)
4145 goto error0;
4146 }
4147
4148 xfs_btree_copy_keys(cur, lkp, rkp, rrecs);
4149 xfs_btree_copy_ptrs(cur, lpp, rpp, rrecs);
4150
4151 xfs_btree_log_keys(cur, lbp, lrecs + 1, lrecs + rrecs);
4152 xfs_btree_log_ptrs(cur, lbp, lrecs + 1, lrecs + rrecs);
4153 } else {
4154 /* It's a leaf. Move records. */
4155 union xfs_btree_rec *lrp; /* left record pointer */
4156 union xfs_btree_rec *rrp; /* right record pointer */
4157
4158 lrp = xfs_btree_rec_addr(cur, lrecs + 1, left);
4159 rrp = xfs_btree_rec_addr(cur, 1, right);
4160
4161 xfs_btree_copy_recs(cur, lrp, rrp, rrecs);
4162 xfs_btree_log_recs(cur, lbp, lrecs + 1, lrecs + rrecs);
4163 }
4164
4165 XFS_BTREE_STATS_INC(cur, join);
4166
4167 /*
4168 * Fix up the number of records and right block pointer in the
4169 * surviving block, and log it.
4170 */
4171 xfs_btree_set_numrecs(left, lrecs + rrecs);
4172 xfs_btree_get_sibling(cur, right, &cptr, XFS_BB_RIGHTSIB);
4173 xfs_btree_set_sibling(cur, left, &cptr, XFS_BB_RIGHTSIB);
4174 xfs_btree_log_block(cur, lbp, XFS_BB_NUMRECS | XFS_BB_RIGHTSIB);
4175
4176 /* If there is a right sibling, point it to the remaining block. */
4177 xfs_btree_get_sibling(cur, left, &cptr, XFS_BB_RIGHTSIB);
4178 if (!xfs_btree_ptr_is_null(cur, &cptr)) {
4179 error = xfs_btree_read_buf_block(cur, &cptr, 0, &rrblock, &rrbp);
4180 if (error)
4181 goto error0;
4182 xfs_btree_set_sibling(cur, rrblock, &lptr, XFS_BB_LEFTSIB);
4183 xfs_btree_log_block(cur, rrbp, XFS_BB_LEFTSIB);
4184 }
4185
4186 /* Free the deleted block. */
4187 error = xfs_btree_free_block(cur, rbp);
4188 if (error)
4189 goto error0;
4190
4191 /*
4192 * If we joined with the left neighbor, set the buffer in the
4193 * cursor to the left block, and fix up the index.
4194 */
4195 if (bp != lbp) {
4196 cur->bc_levels[level].bp = lbp;
4197 cur->bc_levels[level].ptr += lrecs;
4198 cur->bc_levels[level].ra = 0;
4199 }
4200 /*
4201 * If we joined with the right neighbor and there's a level above
4202 * us, increment the cursor at that level.
4203 */
4204 else if ((cur->bc_flags & XFS_BTREE_ROOT_IN_INODE) ||
4205 (level + 1 < cur->bc_nlevels)) {
4206 error = xfs_btree_increment(cur, level + 1, &i);
4207 if (error)
4208 goto error0;
4209 }
4210
4211 /*
4212 * Readjust the ptr at this level if it's not a leaf, since it's
4213 * still pointing at the deletion point, which makes the cursor
4214 * inconsistent. If this makes the ptr 0, the caller fixes it up.
4215 * We can't use decrement because it would change the next level up.
4216 */
4217 if (level > 0)
4218 cur->bc_levels[level].ptr--;
4219
4220 /*
4221 * We combined blocks, so we have to update the parent keys if the
4222 * btree supports overlapped intervals. However,
4223 * bc_levels[level + 1].ptr points to the old block so that the caller
4224 * knows which record to delete. Therefore, the caller must be savvy
4225 * enough to call updkeys for us if we return stat == 2. The other
4226 * exit points from this function don't require deletions further up
4227 * the tree, so they can call updkeys directly.
4228 */
4229
4230 /* Return value means the next level up has something to do. */
4231 *stat = 2;
4232 return 0;
4233
4234error0:
4235 if (tcur)
4236 xfs_btree_del_cursor(tcur, XFS_BTREE_ERROR);
4237 return error;
4238}
4239
4240/*
4241 * Delete the record pointed to by cur.
4242 * The cursor refers to the place where the record was (could be inserted)
4243 * when the operation returns.
4244 */
4245int /* error */
4246xfs_btree_delete(
4247 struct xfs_btree_cur *cur,
4248 int *stat) /* success/failure */
4249{
4250 int error; /* error return value */
4251 int level;
4252 int i;
4253 bool joined = false;
4254
4255 /*
4256 * Go up the tree, starting at leaf level.
4257 *
4258 * If 2 is returned then a join was done; go to the next level.
4259 * Otherwise we are done.
4260 */
4261 for (level = 0, i = 2; i == 2; level++) {
4262 error = xfs_btree_delrec(cur, level, &i);
4263 if (error)
4264 goto error0;
4265 if (i == 2)
4266 joined = true;
4267 }
4268
4269 /*
4270 * If we combined blocks as part of deleting the record, delrec won't
4271 * have updated the parent high keys so we have to do that here.
4272 */
4273 if (joined && (cur->bc_flags & XFS_BTREE_OVERLAPPING)) {
4274 error = xfs_btree_updkeys_force(cur, 0);
4275 if (error)
4276 goto error0;
4277 }
4278
4279 if (i == 0) {
4280 for (level = 1; level < cur->bc_nlevels; level++) {
4281 if (cur->bc_levels[level].ptr == 0) {
4282 error = xfs_btree_decrement(cur, level, &i);
4283 if (error)
4284 goto error0;
4285 break;
4286 }
4287 }
4288 }
4289
4290 *stat = i;
4291 return 0;
4292error0:
4293 return error;
4294}
4295
4296/*
4297 * Get the data from the pointed-to record.
4298 */
4299int /* error */
4300xfs_btree_get_rec(
4301 struct xfs_btree_cur *cur, /* btree cursor */
4302 union xfs_btree_rec **recp, /* output: btree record */
4303 int *stat) /* output: success/failure */
4304{
4305 struct xfs_btree_block *block; /* btree block */
4306 struct xfs_buf *bp; /* buffer pointer */
4307 int ptr; /* record number */
4308#ifdef DEBUG
4309 int error; /* error return value */
4310#endif
4311
4312 ptr = cur->bc_levels[0].ptr;
4313 block = xfs_btree_get_block(cur, 0, &bp);
4314
4315#ifdef DEBUG
4316 error = xfs_btree_check_block(cur, block, 0, bp);
4317 if (error)
4318 return error;
4319#endif
4320
4321 /*
4322 * Off the right end or left end, return failure.
4323 */
4324 if (ptr > xfs_btree_get_numrecs(block) || ptr <= 0) {
4325 *stat = 0;
4326 return 0;
4327 }
4328
4329 /*
4330 * Point to the record and extract its data.
4331 */
4332 *recp = xfs_btree_rec_addr(cur, ptr, block);
4333 *stat = 1;
4334 return 0;
4335}
4336
4337/* Visit a block in a btree. */
4338STATIC int
4339xfs_btree_visit_block(
4340 struct xfs_btree_cur *cur,
4341 int level,
4342 xfs_btree_visit_blocks_fn fn,
4343 void *data)
4344{
4345 struct xfs_btree_block *block;
4346 struct xfs_buf *bp;
4347 union xfs_btree_ptr rptr;
4348 int error;
4349
4350 /* do right sibling readahead */
4351 xfs_btree_readahead(cur, level, XFS_BTCUR_RIGHTRA);
4352 block = xfs_btree_get_block(cur, level, &bp);
4353
4354 /* process the block */
4355 error = fn(cur, level, data);
4356 if (error)
4357 return error;
4358
4359 /* now read rh sibling block for next iteration */
4360 xfs_btree_get_sibling(cur, block, &rptr, XFS_BB_RIGHTSIB);
4361 if (xfs_btree_ptr_is_null(cur, &rptr))
4362 return -ENOENT;
4363
4364 /*
4365 * We only visit blocks once in this walk, so we have to avoid the
4366 * internal xfs_btree_lookup_get_block() optimisation where it will
4367 * return the same block without checking if the right sibling points
4368 * back to us and creates a cyclic reference in the btree.
4369 */
4370 if (cur->bc_flags & XFS_BTREE_LONG_PTRS) {
4371 if (be64_to_cpu(rptr.l) == XFS_DADDR_TO_FSB(cur->bc_mp,
4372 xfs_buf_daddr(bp)))
4373 return -EFSCORRUPTED;
4374 } else {
4375 if (be32_to_cpu(rptr.s) == xfs_daddr_to_agbno(cur->bc_mp,
4376 xfs_buf_daddr(bp)))
4377 return -EFSCORRUPTED;
4378 }
4379 return xfs_btree_lookup_get_block(cur, level, &rptr, &block);
4380}
4381
4382
4383/* Visit every block in a btree. */
4384int
4385xfs_btree_visit_blocks(
4386 struct xfs_btree_cur *cur,
4387 xfs_btree_visit_blocks_fn fn,
4388 unsigned int flags,
4389 void *data)
4390{
4391 union xfs_btree_ptr lptr;
4392 int level;
4393 struct xfs_btree_block *block = NULL;
4394 int error = 0;
4395
4396 cur->bc_ops->init_ptr_from_cur(cur, &lptr);
4397
4398 /* for each level */
4399 for (level = cur->bc_nlevels - 1; level >= 0; level--) {
4400 /* grab the left hand block */
4401 error = xfs_btree_lookup_get_block(cur, level, &lptr, &block);
4402 if (error)
4403 return error;
4404
4405 /* readahead the left most block for the next level down */
4406 if (level > 0) {
4407 union xfs_btree_ptr *ptr;
4408
4409 ptr = xfs_btree_ptr_addr(cur, 1, block);
4410 xfs_btree_readahead_ptr(cur, ptr, 1);
4411
4412 /* save for the next iteration of the loop */
4413 xfs_btree_copy_ptrs(cur, &lptr, ptr, 1);
4414
4415 if (!(flags & XFS_BTREE_VISIT_LEAVES))
4416 continue;
4417 } else if (!(flags & XFS_BTREE_VISIT_RECORDS)) {
4418 continue;
4419 }
4420
4421 /* for each buffer in the level */
4422 do {
4423 error = xfs_btree_visit_block(cur, level, fn, data);
4424 } while (!error);
4425
4426 if (error != -ENOENT)
4427 return error;
4428 }
4429
4430 return 0;
4431}
4432
4433/*
4434 * Change the owner of a btree.
4435 *
4436 * The mechanism we use here is ordered buffer logging. Because we don't know
4437 * how many buffers were are going to need to modify, we don't really want to
4438 * have to make transaction reservations for the worst case of every buffer in a
4439 * full size btree as that may be more space that we can fit in the log....
4440 *
4441 * We do the btree walk in the most optimal manner possible - we have sibling
4442 * pointers so we can just walk all the blocks on each level from left to right
4443 * in a single pass, and then move to the next level and do the same. We can
4444 * also do readahead on the sibling pointers to get IO moving more quickly,
4445 * though for slow disks this is unlikely to make much difference to performance
4446 * as the amount of CPU work we have to do before moving to the next block is
4447 * relatively small.
4448 *
4449 * For each btree block that we load, modify the owner appropriately, set the
4450 * buffer as an ordered buffer and log it appropriately. We need to ensure that
4451 * we mark the region we change dirty so that if the buffer is relogged in
4452 * a subsequent transaction the changes we make here as an ordered buffer are
4453 * correctly relogged in that transaction. If we are in recovery context, then
4454 * just queue the modified buffer as delayed write buffer so the transaction
4455 * recovery completion writes the changes to disk.
4456 */
4457struct xfs_btree_block_change_owner_info {
4458 uint64_t new_owner;
4459 struct list_head *buffer_list;
4460};
4461
4462static int
4463xfs_btree_block_change_owner(
4464 struct xfs_btree_cur *cur,
4465 int level,
4466 void *data)
4467{
4468 struct xfs_btree_block_change_owner_info *bbcoi = data;
4469 struct xfs_btree_block *block;
4470 struct xfs_buf *bp;
4471
4472 /* modify the owner */
4473 block = xfs_btree_get_block(cur, level, &bp);
4474 if (cur->bc_flags & XFS_BTREE_LONG_PTRS) {
4475 if (block->bb_u.l.bb_owner == cpu_to_be64(bbcoi->new_owner))
4476 return 0;
4477 block->bb_u.l.bb_owner = cpu_to_be64(bbcoi->new_owner);
4478 } else {
4479 if (block->bb_u.s.bb_owner == cpu_to_be32(bbcoi->new_owner))
4480 return 0;
4481 block->bb_u.s.bb_owner = cpu_to_be32(bbcoi->new_owner);
4482 }
4483
4484 /*
4485 * If the block is a root block hosted in an inode, we might not have a
4486 * buffer pointer here and we shouldn't attempt to log the change as the
4487 * information is already held in the inode and discarded when the root
4488 * block is formatted into the on-disk inode fork. We still change it,
4489 * though, so everything is consistent in memory.
4490 */
4491 if (!bp) {
4492 ASSERT(cur->bc_flags & XFS_BTREE_ROOT_IN_INODE);
4493 ASSERT(level == cur->bc_nlevels - 1);
4494 return 0;
4495 }
4496
4497 if (cur->bc_tp) {
4498 if (!xfs_trans_ordered_buf(cur->bc_tp, bp)) {
4499 xfs_btree_log_block(cur, bp, XFS_BB_OWNER);
4500 return -EAGAIN;
4501 }
4502 } else {
4503 xfs_buf_delwri_queue(bp, bbcoi->buffer_list);
4504 }
4505
4506 return 0;
4507}
4508
4509int
4510xfs_btree_change_owner(
4511 struct xfs_btree_cur *cur,
4512 uint64_t new_owner,
4513 struct list_head *buffer_list)
4514{
4515 struct xfs_btree_block_change_owner_info bbcoi;
4516
4517 bbcoi.new_owner = new_owner;
4518 bbcoi.buffer_list = buffer_list;
4519
4520 return xfs_btree_visit_blocks(cur, xfs_btree_block_change_owner,
4521 XFS_BTREE_VISIT_ALL, &bbcoi);
4522}
4523
4524/* Verify the v5 fields of a long-format btree block. */
4525xfs_failaddr_t
4526xfs_btree_lblock_v5hdr_verify(
4527 struct xfs_buf *bp,
4528 uint64_t owner)
4529{
4530 struct xfs_mount *mp = bp->b_mount;
4531 struct xfs_btree_block *block = XFS_BUF_TO_BLOCK(bp);
4532
4533 if (!xfs_has_crc(mp))
4534 return __this_address;
4535 if (!uuid_equal(&block->bb_u.l.bb_uuid, &mp->m_sb.sb_meta_uuid))
4536 return __this_address;
4537 if (block->bb_u.l.bb_blkno != cpu_to_be64(xfs_buf_daddr(bp)))
4538 return __this_address;
4539 if (owner != XFS_RMAP_OWN_UNKNOWN &&
4540 be64_to_cpu(block->bb_u.l.bb_owner) != owner)
4541 return __this_address;
4542 return NULL;
4543}
4544
4545/* Verify a long-format btree block. */
4546xfs_failaddr_t
4547xfs_btree_lblock_verify(
4548 struct xfs_buf *bp,
4549 unsigned int max_recs)
4550{
4551 struct xfs_mount *mp = bp->b_mount;
4552 struct xfs_btree_block *block = XFS_BUF_TO_BLOCK(bp);
4553 xfs_fsblock_t fsb;
4554 xfs_failaddr_t fa;
4555
4556 /* numrecs verification */
4557 if (be16_to_cpu(block->bb_numrecs) > max_recs)
4558 return __this_address;
4559
4560 /* sibling pointer verification */
4561 fsb = XFS_DADDR_TO_FSB(mp, xfs_buf_daddr(bp));
4562 fa = xfs_btree_check_lblock_siblings(mp, NULL, -1, fsb,
4563 block->bb_u.l.bb_leftsib);
4564 if (!fa)
4565 fa = xfs_btree_check_lblock_siblings(mp, NULL, -1, fsb,
4566 block->bb_u.l.bb_rightsib);
4567 return fa;
4568}
4569
4570/**
4571 * xfs_btree_sblock_v5hdr_verify() -- verify the v5 fields of a short-format
4572 * btree block
4573 *
4574 * @bp: buffer containing the btree block
4575 */
4576xfs_failaddr_t
4577xfs_btree_sblock_v5hdr_verify(
4578 struct xfs_buf *bp)
4579{
4580 struct xfs_mount *mp = bp->b_mount;
4581 struct xfs_btree_block *block = XFS_BUF_TO_BLOCK(bp);
4582 struct xfs_perag *pag = bp->b_pag;
4583
4584 if (!xfs_has_crc(mp))
4585 return __this_address;
4586 if (!uuid_equal(&block->bb_u.s.bb_uuid, &mp->m_sb.sb_meta_uuid))
4587 return __this_address;
4588 if (block->bb_u.s.bb_blkno != cpu_to_be64(xfs_buf_daddr(bp)))
4589 return __this_address;
4590 if (pag && be32_to_cpu(block->bb_u.s.bb_owner) != pag->pag_agno)
4591 return __this_address;
4592 return NULL;
4593}
4594
4595/**
4596 * xfs_btree_sblock_verify() -- verify a short-format btree block
4597 *
4598 * @bp: buffer containing the btree block
4599 * @max_recs: maximum records allowed in this btree node
4600 */
4601xfs_failaddr_t
4602xfs_btree_sblock_verify(
4603 struct xfs_buf *bp,
4604 unsigned int max_recs)
4605{
4606 struct xfs_mount *mp = bp->b_mount;
4607 struct xfs_btree_block *block = XFS_BUF_TO_BLOCK(bp);
4608 xfs_agblock_t agbno;
4609 xfs_failaddr_t fa;
4610
4611 /* numrecs verification */
4612 if (be16_to_cpu(block->bb_numrecs) > max_recs)
4613 return __this_address;
4614
4615 /* sibling pointer verification */
4616 agbno = xfs_daddr_to_agbno(mp, xfs_buf_daddr(bp));
4617 fa = xfs_btree_check_sblock_siblings(bp->b_pag, NULL, -1, agbno,
4618 block->bb_u.s.bb_leftsib);
4619 if (!fa)
4620 fa = xfs_btree_check_sblock_siblings(bp->b_pag, NULL, -1, agbno,
4621 block->bb_u.s.bb_rightsib);
4622 return fa;
4623}
4624
4625/*
4626 * For the given limits on leaf and keyptr records per block, calculate the
4627 * height of the tree needed to index the number of leaf records.
4628 */
4629unsigned int
4630xfs_btree_compute_maxlevels(
4631 const unsigned int *limits,
4632 unsigned long long records)
4633{
4634 unsigned long long level_blocks = howmany_64(records, limits[0]);
4635 unsigned int height = 1;
4636
4637 while (level_blocks > 1) {
4638 level_blocks = howmany_64(level_blocks, limits[1]);
4639 height++;
4640 }
4641
4642 return height;
4643}
4644
4645/*
4646 * For the given limits on leaf and keyptr records per block, calculate the
4647 * number of blocks needed to index the given number of leaf records.
4648 */
4649unsigned long long
4650xfs_btree_calc_size(
4651 const unsigned int *limits,
4652 unsigned long long records)
4653{
4654 unsigned long long level_blocks = howmany_64(records, limits[0]);
4655 unsigned long long blocks = level_blocks;
4656
4657 while (level_blocks > 1) {
4658 level_blocks = howmany_64(level_blocks, limits[1]);
4659 blocks += level_blocks;
4660 }
4661
4662 return blocks;
4663}
4664
4665/*
4666 * Given a number of available blocks for the btree to consume with records and
4667 * pointers, calculate the height of the tree needed to index all the records
4668 * that space can hold based on the number of pointers each interior node
4669 * holds.
4670 *
4671 * We start by assuming a single level tree consumes a single block, then track
4672 * the number of blocks each node level consumes until we no longer have space
4673 * to store the next node level. At this point, we are indexing all the leaf
4674 * blocks in the space, and there's no more free space to split the tree any
4675 * further. That's our maximum btree height.
4676 */
4677unsigned int
4678xfs_btree_space_to_height(
4679 const unsigned int *limits,
4680 unsigned long long leaf_blocks)
4681{
4682 /*
4683 * The root btree block can have fewer than minrecs pointers in it
4684 * because the tree might not be big enough to require that amount of
4685 * fanout. Hence it has a minimum size of 2 pointers, not limits[1].
4686 */
4687 unsigned long long node_blocks = 2;
4688 unsigned long long blocks_left = leaf_blocks - 1;
4689 unsigned int height = 1;
4690
4691 if (leaf_blocks < 1)
4692 return 0;
4693
4694 while (node_blocks < blocks_left) {
4695 blocks_left -= node_blocks;
4696 node_blocks *= limits[1];
4697 height++;
4698 }
4699
4700 return height;
4701}
4702
4703/*
4704 * Query a regular btree for all records overlapping a given interval.
4705 * Start with a LE lookup of the key of low_rec and return all records
4706 * until we find a record with a key greater than the key of high_rec.
4707 */
4708STATIC int
4709xfs_btree_simple_query_range(
4710 struct xfs_btree_cur *cur,
4711 const union xfs_btree_key *low_key,
4712 const union xfs_btree_key *high_key,
4713 xfs_btree_query_range_fn fn,
4714 void *priv)
4715{
4716 union xfs_btree_rec *recp;
4717 union xfs_btree_key rec_key;
4718 int stat;
4719 bool firstrec = true;
4720 int error;
4721
4722 ASSERT(cur->bc_ops->init_high_key_from_rec);
4723 ASSERT(cur->bc_ops->diff_two_keys);
4724
4725 /*
4726 * Find the leftmost record. The btree cursor must be set
4727 * to the low record used to generate low_key.
4728 */
4729 stat = 0;
4730 error = xfs_btree_lookup(cur, XFS_LOOKUP_LE, &stat);
4731 if (error)
4732 goto out;
4733
4734 /* Nothing? See if there's anything to the right. */
4735 if (!stat) {
4736 error = xfs_btree_increment(cur, 0, &stat);
4737 if (error)
4738 goto out;
4739 }
4740
4741 while (stat) {
4742 /* Find the record. */
4743 error = xfs_btree_get_rec(cur, &recp, &stat);
4744 if (error || !stat)
4745 break;
4746
4747 /* Skip if low_key > high_key(rec). */
4748 if (firstrec) {
4749 cur->bc_ops->init_high_key_from_rec(&rec_key, recp);
4750 firstrec = false;
4751 if (xfs_btree_keycmp_gt(cur, low_key, &rec_key))
4752 goto advloop;
4753 }
4754
4755 /* Stop if low_key(rec) > high_key. */
4756 cur->bc_ops->init_key_from_rec(&rec_key, recp);
4757 if (xfs_btree_keycmp_gt(cur, &rec_key, high_key))
4758 break;
4759
4760 /* Callback */
4761 error = fn(cur, recp, priv);
4762 if (error)
4763 break;
4764
4765advloop:
4766 /* Move on to the next record. */
4767 error = xfs_btree_increment(cur, 0, &stat);
4768 if (error)
4769 break;
4770 }
4771
4772out:
4773 return error;
4774}
4775
4776/*
4777 * Query an overlapped interval btree for all records overlapping a given
4778 * interval. This function roughly follows the algorithm given in
4779 * "Interval Trees" of _Introduction to Algorithms_, which is section
4780 * 14.3 in the 2nd and 3rd editions.
4781 *
4782 * First, generate keys for the low and high records passed in.
4783 *
4784 * For any leaf node, generate the high and low keys for the record.
4785 * If the record keys overlap with the query low/high keys, pass the
4786 * record to the function iterator.
4787 *
4788 * For any internal node, compare the low and high keys of each
4789 * pointer against the query low/high keys. If there's an overlap,
4790 * follow the pointer.
4791 *
4792 * As an optimization, we stop scanning a block when we find a low key
4793 * that is greater than the query's high key.
4794 */
4795STATIC int
4796xfs_btree_overlapped_query_range(
4797 struct xfs_btree_cur *cur,
4798 const union xfs_btree_key *low_key,
4799 const union xfs_btree_key *high_key,
4800 xfs_btree_query_range_fn fn,
4801 void *priv)
4802{
4803 union xfs_btree_ptr ptr;
4804 union xfs_btree_ptr *pp;
4805 union xfs_btree_key rec_key;
4806 union xfs_btree_key rec_hkey;
4807 union xfs_btree_key *lkp;
4808 union xfs_btree_key *hkp;
4809 union xfs_btree_rec *recp;
4810 struct xfs_btree_block *block;
4811 int level;
4812 struct xfs_buf *bp;
4813 int i;
4814 int error;
4815
4816 /* Load the root of the btree. */
4817 level = cur->bc_nlevels - 1;
4818 cur->bc_ops->init_ptr_from_cur(cur, &ptr);
4819 error = xfs_btree_lookup_get_block(cur, level, &ptr, &block);
4820 if (error)
4821 return error;
4822 xfs_btree_get_block(cur, level, &bp);
4823 trace_xfs_btree_overlapped_query_range(cur, level, bp);
4824#ifdef DEBUG
4825 error = xfs_btree_check_block(cur, block, level, bp);
4826 if (error)
4827 goto out;
4828#endif
4829 cur->bc_levels[level].ptr = 1;
4830
4831 while (level < cur->bc_nlevels) {
4832 block = xfs_btree_get_block(cur, level, &bp);
4833
4834 /* End of node, pop back towards the root. */
4835 if (cur->bc_levels[level].ptr >
4836 be16_to_cpu(block->bb_numrecs)) {
4837pop_up:
4838 if (level < cur->bc_nlevels - 1)
4839 cur->bc_levels[level + 1].ptr++;
4840 level++;
4841 continue;
4842 }
4843
4844 if (level == 0) {
4845 /* Handle a leaf node. */
4846 recp = xfs_btree_rec_addr(cur, cur->bc_levels[0].ptr,
4847 block);
4848
4849 cur->bc_ops->init_high_key_from_rec(&rec_hkey, recp);
4850 cur->bc_ops->init_key_from_rec(&rec_key, recp);
4851
4852 /*
4853 * If (query's high key < record's low key), then there
4854 * are no more interesting records in this block. Pop
4855 * up to the leaf level to find more record blocks.
4856 *
4857 * If (record's high key >= query's low key) and
4858 * (query's high key >= record's low key), then
4859 * this record overlaps the query range; callback.
4860 */
4861 if (xfs_btree_keycmp_lt(cur, high_key, &rec_key))
4862 goto pop_up;
4863 if (xfs_btree_keycmp_ge(cur, &rec_hkey, low_key)) {
4864 error = fn(cur, recp, priv);
4865 if (error)
4866 break;
4867 }
4868 cur->bc_levels[level].ptr++;
4869 continue;
4870 }
4871
4872 /* Handle an internal node. */
4873 lkp = xfs_btree_key_addr(cur, cur->bc_levels[level].ptr, block);
4874 hkp = xfs_btree_high_key_addr(cur, cur->bc_levels[level].ptr,
4875 block);
4876 pp = xfs_btree_ptr_addr(cur, cur->bc_levels[level].ptr, block);
4877
4878 /*
4879 * If (query's high key < pointer's low key), then there are no
4880 * more interesting keys in this block. Pop up one leaf level
4881 * to continue looking for records.
4882 *
4883 * If (pointer's high key >= query's low key) and
4884 * (query's high key >= pointer's low key), then
4885 * this record overlaps the query range; follow pointer.
4886 */
4887 if (xfs_btree_keycmp_lt(cur, high_key, lkp))
4888 goto pop_up;
4889 if (xfs_btree_keycmp_ge(cur, hkp, low_key)) {
4890 level--;
4891 error = xfs_btree_lookup_get_block(cur, level, pp,
4892 &block);
4893 if (error)
4894 goto out;
4895 xfs_btree_get_block(cur, level, &bp);
4896 trace_xfs_btree_overlapped_query_range(cur, level, bp);
4897#ifdef DEBUG
4898 error = xfs_btree_check_block(cur, block, level, bp);
4899 if (error)
4900 goto out;
4901#endif
4902 cur->bc_levels[level].ptr = 1;
4903 continue;
4904 }
4905 cur->bc_levels[level].ptr++;
4906 }
4907
4908out:
4909 /*
4910 * If we don't end this function with the cursor pointing at a record
4911 * block, a subsequent non-error cursor deletion will not release
4912 * node-level buffers, causing a buffer leak. This is quite possible
4913 * with a zero-results range query, so release the buffers if we
4914 * failed to return any results.
4915 */
4916 if (cur->bc_levels[0].bp == NULL) {
4917 for (i = 0; i < cur->bc_nlevels; i++) {
4918 if (cur->bc_levels[i].bp) {
4919 xfs_trans_brelse(cur->bc_tp,
4920 cur->bc_levels[i].bp);
4921 cur->bc_levels[i].bp = NULL;
4922 cur->bc_levels[i].ptr = 0;
4923 cur->bc_levels[i].ra = 0;
4924 }
4925 }
4926 }
4927
4928 return error;
4929}
4930
4931static inline void
4932xfs_btree_key_from_irec(
4933 struct xfs_btree_cur *cur,
4934 union xfs_btree_key *key,
4935 const union xfs_btree_irec *irec)
4936{
4937 union xfs_btree_rec rec;
4938
4939 cur->bc_rec = *irec;
4940 cur->bc_ops->init_rec_from_cur(cur, &rec);
4941 cur->bc_ops->init_key_from_rec(key, &rec);
4942}
4943
4944/*
4945 * Query a btree for all records overlapping a given interval of keys. The
4946 * supplied function will be called with each record found; return one of the
4947 * XFS_BTREE_QUERY_RANGE_{CONTINUE,ABORT} values or the usual negative error
4948 * code. This function returns -ECANCELED, zero, or a negative error code.
4949 */
4950int
4951xfs_btree_query_range(
4952 struct xfs_btree_cur *cur,
4953 const union xfs_btree_irec *low_rec,
4954 const union xfs_btree_irec *high_rec,
4955 xfs_btree_query_range_fn fn,
4956 void *priv)
4957{
4958 union xfs_btree_key low_key;
4959 union xfs_btree_key high_key;
4960
4961 /* Find the keys of both ends of the interval. */
4962 xfs_btree_key_from_irec(cur, &high_key, high_rec);
4963 xfs_btree_key_from_irec(cur, &low_key, low_rec);
4964
4965 /* Enforce low key <= high key. */
4966 if (!xfs_btree_keycmp_le(cur, &low_key, &high_key))
4967 return -EINVAL;
4968
4969 if (!(cur->bc_flags & XFS_BTREE_OVERLAPPING))
4970 return xfs_btree_simple_query_range(cur, &low_key,
4971 &high_key, fn, priv);
4972 return xfs_btree_overlapped_query_range(cur, &low_key, &high_key,
4973 fn, priv);
4974}
4975
4976/* Query a btree for all records. */
4977int
4978xfs_btree_query_all(
4979 struct xfs_btree_cur *cur,
4980 xfs_btree_query_range_fn fn,
4981 void *priv)
4982{
4983 union xfs_btree_key low_key;
4984 union xfs_btree_key high_key;
4985
4986 memset(&cur->bc_rec, 0, sizeof(cur->bc_rec));
4987 memset(&low_key, 0, sizeof(low_key));
4988 memset(&high_key, 0xFF, sizeof(high_key));
4989
4990 return xfs_btree_simple_query_range(cur, &low_key, &high_key, fn, priv);
4991}
4992
4993static int
4994xfs_btree_count_blocks_helper(
4995 struct xfs_btree_cur *cur,
4996 int level,
4997 void *data)
4998{
4999 xfs_extlen_t *blocks = data;
5000 (*blocks)++;
5001
5002 return 0;
5003}
5004
5005/* Count the blocks in a btree and return the result in *blocks. */
5006int
5007xfs_btree_count_blocks(
5008 struct xfs_btree_cur *cur,
5009 xfs_extlen_t *blocks)
5010{
5011 *blocks = 0;
5012 return xfs_btree_visit_blocks(cur, xfs_btree_count_blocks_helper,
5013 XFS_BTREE_VISIT_ALL, blocks);
5014}
5015
5016/* Compare two btree pointers. */
5017int64_t
5018xfs_btree_diff_two_ptrs(
5019 struct xfs_btree_cur *cur,
5020 const union xfs_btree_ptr *a,
5021 const union xfs_btree_ptr *b)
5022{
5023 if (cur->bc_flags & XFS_BTREE_LONG_PTRS)
5024 return (int64_t)be64_to_cpu(a->l) - be64_to_cpu(b->l);
5025 return (int64_t)be32_to_cpu(a->s) - be32_to_cpu(b->s);
5026}
5027
5028struct xfs_btree_has_records {
5029 /* Keys for the start and end of the range we want to know about. */
5030 union xfs_btree_key start_key;
5031 union xfs_btree_key end_key;
5032
5033 /* Mask for key comparisons, if desired. */
5034 const union xfs_btree_key *key_mask;
5035
5036 /* Highest record key we've seen so far. */
5037 union xfs_btree_key high_key;
5038
5039 enum xbtree_recpacking outcome;
5040};
5041
5042STATIC int
5043xfs_btree_has_records_helper(
5044 struct xfs_btree_cur *cur,
5045 const union xfs_btree_rec *rec,
5046 void *priv)
5047{
5048 union xfs_btree_key rec_key;
5049 union xfs_btree_key rec_high_key;
5050 struct xfs_btree_has_records *info = priv;
5051 enum xbtree_key_contig key_contig;
5052
5053 cur->bc_ops->init_key_from_rec(&rec_key, rec);
5054
5055 if (info->outcome == XBTREE_RECPACKING_EMPTY) {
5056 info->outcome = XBTREE_RECPACKING_SPARSE;
5057
5058 /*
5059 * If the first record we find does not overlap the start key,
5060 * then there is a hole at the start of the search range.
5061 * Classify this as sparse and stop immediately.
5062 */
5063 if (xfs_btree_masked_keycmp_lt(cur, &info->start_key, &rec_key,
5064 info->key_mask))
5065 return -ECANCELED;
5066 } else {
5067 /*
5068 * If a subsequent record does not overlap with the any record
5069 * we've seen so far, there is a hole in the middle of the
5070 * search range. Classify this as sparse and stop.
5071 * If the keys overlap and this btree does not allow overlap,
5072 * signal corruption.
5073 */
5074 key_contig = cur->bc_ops->keys_contiguous(cur, &info->high_key,
5075 &rec_key, info->key_mask);
5076 if (key_contig == XBTREE_KEY_OVERLAP &&
5077 !(cur->bc_flags & XFS_BTREE_OVERLAPPING))
5078 return -EFSCORRUPTED;
5079 if (key_contig == XBTREE_KEY_GAP)
5080 return -ECANCELED;
5081 }
5082
5083 /*
5084 * If high_key(rec) is larger than any other high key we've seen,
5085 * remember it for later.
5086 */
5087 cur->bc_ops->init_high_key_from_rec(&rec_high_key, rec);
5088 if (xfs_btree_masked_keycmp_gt(cur, &rec_high_key, &info->high_key,
5089 info->key_mask))
5090 info->high_key = rec_high_key; /* struct copy */
5091
5092 return 0;
5093}
5094
5095/*
5096 * Scan part of the keyspace of a btree and tell us if that keyspace does not
5097 * map to any records; is fully mapped to records; or is partially mapped to
5098 * records. This is the btree record equivalent to determining if a file is
5099 * sparse.
5100 *
5101 * For most btree types, the record scan should use all available btree key
5102 * fields to compare the keys encountered. These callers should pass NULL for
5103 * @mask. However, some callers (e.g. scanning physical space in the rmapbt)
5104 * want to ignore some part of the btree record keyspace when performing the
5105 * comparison. These callers should pass in a union xfs_btree_key object with
5106 * the fields that *should* be a part of the comparison set to any nonzero
5107 * value, and the rest zeroed.
5108 */
5109int
5110xfs_btree_has_records(
5111 struct xfs_btree_cur *cur,
5112 const union xfs_btree_irec *low,
5113 const union xfs_btree_irec *high,
5114 const union xfs_btree_key *mask,
5115 enum xbtree_recpacking *outcome)
5116{
5117 struct xfs_btree_has_records info = {
5118 .outcome = XBTREE_RECPACKING_EMPTY,
5119 .key_mask = mask,
5120 };
5121 int error;
5122
5123 /* Not all btrees support this operation. */
5124 if (!cur->bc_ops->keys_contiguous) {
5125 ASSERT(0);
5126 return -EOPNOTSUPP;
5127 }
5128
5129 xfs_btree_key_from_irec(cur, &info.start_key, low);
5130 xfs_btree_key_from_irec(cur, &info.end_key, high);
5131
5132 error = xfs_btree_query_range(cur, low, high,
5133 xfs_btree_has_records_helper, &info);
5134 if (error == -ECANCELED)
5135 goto out;
5136 if (error)
5137 return error;
5138
5139 if (info.outcome == XBTREE_RECPACKING_EMPTY)
5140 goto out;
5141
5142 /*
5143 * If the largest high_key(rec) we saw during the walk is greater than
5144 * the end of the search range, classify this as full. Otherwise,
5145 * there is a hole at the end of the search range.
5146 */
5147 if (xfs_btree_masked_keycmp_ge(cur, &info.high_key, &info.end_key,
5148 mask))
5149 info.outcome = XBTREE_RECPACKING_FULL;
5150
5151out:
5152 *outcome = info.outcome;
5153 return 0;
5154}
5155
5156/* Are there more records in this btree? */
5157bool
5158xfs_btree_has_more_records(
5159 struct xfs_btree_cur *cur)
5160{
5161 struct xfs_btree_block *block;
5162 struct xfs_buf *bp;
5163
5164 block = xfs_btree_get_block(cur, 0, &bp);
5165
5166 /* There are still records in this block. */
5167 if (cur->bc_levels[0].ptr < xfs_btree_get_numrecs(block))
5168 return true;
5169
5170 /* There are more record blocks. */
5171 if (cur->bc_flags & XFS_BTREE_LONG_PTRS)
5172 return block->bb_u.l.bb_rightsib != cpu_to_be64(NULLFSBLOCK);
5173 else
5174 return block->bb_u.s.bb_rightsib != cpu_to_be32(NULLAGBLOCK);
5175}
5176
5177/* Set up all the btree cursor caches. */
5178int __init
5179xfs_btree_init_cur_caches(void)
5180{
5181 int error;
5182
5183 error = xfs_allocbt_init_cur_cache();
5184 if (error)
5185 return error;
5186 error = xfs_inobt_init_cur_cache();
5187 if (error)
5188 goto err;
5189 error = xfs_bmbt_init_cur_cache();
5190 if (error)
5191 goto err;
5192 error = xfs_rmapbt_init_cur_cache();
5193 if (error)
5194 goto err;
5195 error = xfs_refcountbt_init_cur_cache();
5196 if (error)
5197 goto err;
5198
5199 return 0;
5200err:
5201 xfs_btree_destroy_cur_caches();
5202 return error;
5203}
5204
5205/* Destroy all the btree cursor caches, if they've been allocated. */
5206void
5207xfs_btree_destroy_cur_caches(void)
5208{
5209 xfs_allocbt_destroy_cur_cache();
5210 xfs_inobt_destroy_cur_cache();
5211 xfs_bmbt_destroy_cur_cache();
5212 xfs_rmapbt_destroy_cur_cache();
5213 xfs_refcountbt_destroy_cur_cache();
5214}
5215
5216/* Move the btree cursor before the first record. */
5217int
5218xfs_btree_goto_left_edge(
5219 struct xfs_btree_cur *cur)
5220{
5221 int stat = 0;
5222 int error;
5223
5224 memset(&cur->bc_rec, 0, sizeof(cur->bc_rec));
5225 error = xfs_btree_lookup(cur, XFS_LOOKUP_LE, &stat);
5226 if (error)
5227 return error;
5228 if (!stat)
5229 return 0;
5230
5231 error = xfs_btree_decrement(cur, 0, &stat);
5232 if (error)
5233 return error;
5234 if (stat != 0) {
5235 ASSERT(0);
5236 return -EFSCORRUPTED;
5237 }
5238
5239 return 0;
5240}