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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}