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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright (c) 2014 Red Hat, Inc.
4 * All Rights Reserved.
5 */
6#include "xfs.h"
7#include "xfs_fs.h"
8#include "xfs_shared.h"
9#include "xfs_format.h"
10#include "xfs_log_format.h"
11#include "xfs_trans_resv.h"
12#include "xfs_mount.h"
13#include "xfs_trans.h"
14#include "xfs_alloc.h"
15#include "xfs_btree.h"
16#include "xfs_btree_staging.h"
17#include "xfs_rmap.h"
18#include "xfs_rmap_btree.h"
19#include "xfs_trace.h"
20#include "xfs_error.h"
21#include "xfs_extent_busy.h"
22#include "xfs_ag.h"
23#include "xfs_ag_resv.h"
24
25static struct kmem_cache *xfs_rmapbt_cur_cache;
26
27/*
28 * Reverse map btree.
29 *
30 * This is a per-ag tree used to track the owner(s) of a given extent. With
31 * reflink it is possible for there to be multiple owners, which is a departure
32 * from classic XFS. Owner records for data extents are inserted when the
33 * extent is mapped and removed when an extent is unmapped. Owner records for
34 * all other block types (i.e. metadata) are inserted when an extent is
35 * allocated and removed when an extent is freed. There can only be one owner
36 * of a metadata extent, usually an inode or some other metadata structure like
37 * an AG btree.
38 *
39 * The rmap btree is part of the free space management, so blocks for the tree
40 * are sourced from the agfl. Hence we need transaction reservation support for
41 * this tree so that the freelist is always large enough. This also impacts on
42 * the minimum space we need to leave free in the AG.
43 *
44 * The tree is ordered by [ag block, owner, offset]. This is a large key size,
45 * but it is the only way to enforce unique keys when a block can be owned by
46 * multiple files at any offset. There's no need to order/search by extent
47 * size for online updating/management of the tree. It is intended that most
48 * reverse lookups will be to find the owner(s) of a particular block, or to
49 * try to recover tree and file data from corrupt primary metadata.
50 */
51
52static struct xfs_btree_cur *
53xfs_rmapbt_dup_cursor(
54 struct xfs_btree_cur *cur)
55{
56 return xfs_rmapbt_init_cursor(cur->bc_mp, cur->bc_tp,
57 cur->bc_ag.agbp, cur->bc_ag.pag);
58}
59
60STATIC void
61xfs_rmapbt_set_root(
62 struct xfs_btree_cur *cur,
63 const union xfs_btree_ptr *ptr,
64 int inc)
65{
66 struct xfs_buf *agbp = cur->bc_ag.agbp;
67 struct xfs_agf *agf = agbp->b_addr;
68 int btnum = cur->bc_btnum;
69
70 ASSERT(ptr->s != 0);
71
72 agf->agf_roots[btnum] = ptr->s;
73 be32_add_cpu(&agf->agf_levels[btnum], inc);
74 cur->bc_ag.pag->pagf_levels[btnum] += inc;
75
76 xfs_alloc_log_agf(cur->bc_tp, agbp, XFS_AGF_ROOTS | XFS_AGF_LEVELS);
77}
78
79STATIC int
80xfs_rmapbt_alloc_block(
81 struct xfs_btree_cur *cur,
82 const union xfs_btree_ptr *start,
83 union xfs_btree_ptr *new,
84 int *stat)
85{
86 struct xfs_buf *agbp = cur->bc_ag.agbp;
87 struct xfs_agf *agf = agbp->b_addr;
88 struct xfs_perag *pag = cur->bc_ag.pag;
89 int error;
90 xfs_agblock_t bno;
91
92 /* Allocate the new block from the freelist. If we can't, give up. */
93 error = xfs_alloc_get_freelist(pag, cur->bc_tp, cur->bc_ag.agbp,
94 &bno, 1);
95 if (error)
96 return error;
97
98 trace_xfs_rmapbt_alloc_block(cur->bc_mp, pag->pag_agno, bno, 1);
99 if (bno == NULLAGBLOCK) {
100 *stat = 0;
101 return 0;
102 }
103
104 xfs_extent_busy_reuse(cur->bc_mp, pag, bno, 1, false);
105
106 new->s = cpu_to_be32(bno);
107 be32_add_cpu(&agf->agf_rmap_blocks, 1);
108 xfs_alloc_log_agf(cur->bc_tp, agbp, XFS_AGF_RMAP_BLOCKS);
109
110 xfs_ag_resv_rmapbt_alloc(cur->bc_mp, pag->pag_agno);
111
112 *stat = 1;
113 return 0;
114}
115
116STATIC int
117xfs_rmapbt_free_block(
118 struct xfs_btree_cur *cur,
119 struct xfs_buf *bp)
120{
121 struct xfs_buf *agbp = cur->bc_ag.agbp;
122 struct xfs_agf *agf = agbp->b_addr;
123 struct xfs_perag *pag = cur->bc_ag.pag;
124 xfs_agblock_t bno;
125 int error;
126
127 bno = xfs_daddr_to_agbno(cur->bc_mp, xfs_buf_daddr(bp));
128 trace_xfs_rmapbt_free_block(cur->bc_mp, pag->pag_agno,
129 bno, 1);
130 be32_add_cpu(&agf->agf_rmap_blocks, -1);
131 xfs_alloc_log_agf(cur->bc_tp, agbp, XFS_AGF_RMAP_BLOCKS);
132 error = xfs_alloc_put_freelist(pag, cur->bc_tp, agbp, NULL, bno, 1);
133 if (error)
134 return error;
135
136 xfs_extent_busy_insert(cur->bc_tp, pag, bno, 1,
137 XFS_EXTENT_BUSY_SKIP_DISCARD);
138
139 xfs_ag_resv_free_extent(pag, XFS_AG_RESV_RMAPBT, NULL, 1);
140 return 0;
141}
142
143STATIC int
144xfs_rmapbt_get_minrecs(
145 struct xfs_btree_cur *cur,
146 int level)
147{
148 return cur->bc_mp->m_rmap_mnr[level != 0];
149}
150
151STATIC int
152xfs_rmapbt_get_maxrecs(
153 struct xfs_btree_cur *cur,
154 int level)
155{
156 return cur->bc_mp->m_rmap_mxr[level != 0];
157}
158
159STATIC void
160xfs_rmapbt_init_key_from_rec(
161 union xfs_btree_key *key,
162 const union xfs_btree_rec *rec)
163{
164 key->rmap.rm_startblock = rec->rmap.rm_startblock;
165 key->rmap.rm_owner = rec->rmap.rm_owner;
166 key->rmap.rm_offset = rec->rmap.rm_offset;
167}
168
169/*
170 * The high key for a reverse mapping record can be computed by shifting
171 * the startblock and offset to the highest value that would still map
172 * to that record. In practice this means that we add blockcount-1 to
173 * the startblock for all records, and if the record is for a data/attr
174 * fork mapping, we add blockcount-1 to the offset too.
175 */
176STATIC void
177xfs_rmapbt_init_high_key_from_rec(
178 union xfs_btree_key *key,
179 const union xfs_btree_rec *rec)
180{
181 uint64_t off;
182 int adj;
183
184 adj = be32_to_cpu(rec->rmap.rm_blockcount) - 1;
185
186 key->rmap.rm_startblock = rec->rmap.rm_startblock;
187 be32_add_cpu(&key->rmap.rm_startblock, adj);
188 key->rmap.rm_owner = rec->rmap.rm_owner;
189 key->rmap.rm_offset = rec->rmap.rm_offset;
190 if (XFS_RMAP_NON_INODE_OWNER(be64_to_cpu(rec->rmap.rm_owner)) ||
191 XFS_RMAP_IS_BMBT_BLOCK(be64_to_cpu(rec->rmap.rm_offset)))
192 return;
193 off = be64_to_cpu(key->rmap.rm_offset);
194 off = (XFS_RMAP_OFF(off) + adj) | (off & ~XFS_RMAP_OFF_MASK);
195 key->rmap.rm_offset = cpu_to_be64(off);
196}
197
198STATIC void
199xfs_rmapbt_init_rec_from_cur(
200 struct xfs_btree_cur *cur,
201 union xfs_btree_rec *rec)
202{
203 rec->rmap.rm_startblock = cpu_to_be32(cur->bc_rec.r.rm_startblock);
204 rec->rmap.rm_blockcount = cpu_to_be32(cur->bc_rec.r.rm_blockcount);
205 rec->rmap.rm_owner = cpu_to_be64(cur->bc_rec.r.rm_owner);
206 rec->rmap.rm_offset = cpu_to_be64(
207 xfs_rmap_irec_offset_pack(&cur->bc_rec.r));
208}
209
210STATIC void
211xfs_rmapbt_init_ptr_from_cur(
212 struct xfs_btree_cur *cur,
213 union xfs_btree_ptr *ptr)
214{
215 struct xfs_agf *agf = cur->bc_ag.agbp->b_addr;
216
217 ASSERT(cur->bc_ag.pag->pag_agno == be32_to_cpu(agf->agf_seqno));
218
219 ptr->s = agf->agf_roots[cur->bc_btnum];
220}
221
222STATIC int64_t
223xfs_rmapbt_key_diff(
224 struct xfs_btree_cur *cur,
225 const union xfs_btree_key *key)
226{
227 struct xfs_rmap_irec *rec = &cur->bc_rec.r;
228 const struct xfs_rmap_key *kp = &key->rmap;
229 __u64 x, y;
230 int64_t d;
231
232 d = (int64_t)be32_to_cpu(kp->rm_startblock) - rec->rm_startblock;
233 if (d)
234 return d;
235
236 x = be64_to_cpu(kp->rm_owner);
237 y = rec->rm_owner;
238 if (x > y)
239 return 1;
240 else if (y > x)
241 return -1;
242
243 x = XFS_RMAP_OFF(be64_to_cpu(kp->rm_offset));
244 y = rec->rm_offset;
245 if (x > y)
246 return 1;
247 else if (y > x)
248 return -1;
249 return 0;
250}
251
252STATIC int64_t
253xfs_rmapbt_diff_two_keys(
254 struct xfs_btree_cur *cur,
255 const union xfs_btree_key *k1,
256 const union xfs_btree_key *k2)
257{
258 const struct xfs_rmap_key *kp1 = &k1->rmap;
259 const struct xfs_rmap_key *kp2 = &k2->rmap;
260 int64_t d;
261 __u64 x, y;
262
263 d = (int64_t)be32_to_cpu(kp1->rm_startblock) -
264 be32_to_cpu(kp2->rm_startblock);
265 if (d)
266 return d;
267
268 x = be64_to_cpu(kp1->rm_owner);
269 y = be64_to_cpu(kp2->rm_owner);
270 if (x > y)
271 return 1;
272 else if (y > x)
273 return -1;
274
275 x = XFS_RMAP_OFF(be64_to_cpu(kp1->rm_offset));
276 y = XFS_RMAP_OFF(be64_to_cpu(kp2->rm_offset));
277 if (x > y)
278 return 1;
279 else if (y > x)
280 return -1;
281 return 0;
282}
283
284static xfs_failaddr_t
285xfs_rmapbt_verify(
286 struct xfs_buf *bp)
287{
288 struct xfs_mount *mp = bp->b_mount;
289 struct xfs_btree_block *block = XFS_BUF_TO_BLOCK(bp);
290 struct xfs_perag *pag = bp->b_pag;
291 xfs_failaddr_t fa;
292 unsigned int level;
293
294 /*
295 * magic number and level verification
296 *
297 * During growfs operations, we can't verify the exact level or owner as
298 * the perag is not fully initialised and hence not attached to the
299 * buffer. In this case, check against the maximum tree depth.
300 *
301 * Similarly, during log recovery we will have a perag structure
302 * attached, but the agf information will not yet have been initialised
303 * from the on disk AGF. Again, we can only check against maximum limits
304 * in this case.
305 */
306 if (!xfs_verify_magic(bp, block->bb_magic))
307 return __this_address;
308
309 if (!xfs_has_rmapbt(mp))
310 return __this_address;
311 fa = xfs_btree_sblock_v5hdr_verify(bp);
312 if (fa)
313 return fa;
314
315 level = be16_to_cpu(block->bb_level);
316 if (pag && pag->pagf_init) {
317 if (level >= pag->pagf_levels[XFS_BTNUM_RMAPi])
318 return __this_address;
319 } else if (level >= mp->m_rmap_maxlevels)
320 return __this_address;
321
322 return xfs_btree_sblock_verify(bp, mp->m_rmap_mxr[level != 0]);
323}
324
325static void
326xfs_rmapbt_read_verify(
327 struct xfs_buf *bp)
328{
329 xfs_failaddr_t fa;
330
331 if (!xfs_btree_sblock_verify_crc(bp))
332 xfs_verifier_error(bp, -EFSBADCRC, __this_address);
333 else {
334 fa = xfs_rmapbt_verify(bp);
335 if (fa)
336 xfs_verifier_error(bp, -EFSCORRUPTED, fa);
337 }
338
339 if (bp->b_error)
340 trace_xfs_btree_corrupt(bp, _RET_IP_);
341}
342
343static void
344xfs_rmapbt_write_verify(
345 struct xfs_buf *bp)
346{
347 xfs_failaddr_t fa;
348
349 fa = xfs_rmapbt_verify(bp);
350 if (fa) {
351 trace_xfs_btree_corrupt(bp, _RET_IP_);
352 xfs_verifier_error(bp, -EFSCORRUPTED, fa);
353 return;
354 }
355 xfs_btree_sblock_calc_crc(bp);
356
357}
358
359const struct xfs_buf_ops xfs_rmapbt_buf_ops = {
360 .name = "xfs_rmapbt",
361 .magic = { 0, cpu_to_be32(XFS_RMAP_CRC_MAGIC) },
362 .verify_read = xfs_rmapbt_read_verify,
363 .verify_write = xfs_rmapbt_write_verify,
364 .verify_struct = xfs_rmapbt_verify,
365};
366
367STATIC int
368xfs_rmapbt_keys_inorder(
369 struct xfs_btree_cur *cur,
370 const union xfs_btree_key *k1,
371 const union xfs_btree_key *k2)
372{
373 uint32_t x;
374 uint32_t y;
375 uint64_t a;
376 uint64_t b;
377
378 x = be32_to_cpu(k1->rmap.rm_startblock);
379 y = be32_to_cpu(k2->rmap.rm_startblock);
380 if (x < y)
381 return 1;
382 else if (x > y)
383 return 0;
384 a = be64_to_cpu(k1->rmap.rm_owner);
385 b = be64_to_cpu(k2->rmap.rm_owner);
386 if (a < b)
387 return 1;
388 else if (a > b)
389 return 0;
390 a = XFS_RMAP_OFF(be64_to_cpu(k1->rmap.rm_offset));
391 b = XFS_RMAP_OFF(be64_to_cpu(k2->rmap.rm_offset));
392 if (a <= b)
393 return 1;
394 return 0;
395}
396
397STATIC int
398xfs_rmapbt_recs_inorder(
399 struct xfs_btree_cur *cur,
400 const union xfs_btree_rec *r1,
401 const union xfs_btree_rec *r2)
402{
403 uint32_t x;
404 uint32_t y;
405 uint64_t a;
406 uint64_t b;
407
408 x = be32_to_cpu(r1->rmap.rm_startblock);
409 y = be32_to_cpu(r2->rmap.rm_startblock);
410 if (x < y)
411 return 1;
412 else if (x > y)
413 return 0;
414 a = be64_to_cpu(r1->rmap.rm_owner);
415 b = be64_to_cpu(r2->rmap.rm_owner);
416 if (a < b)
417 return 1;
418 else if (a > b)
419 return 0;
420 a = XFS_RMAP_OFF(be64_to_cpu(r1->rmap.rm_offset));
421 b = XFS_RMAP_OFF(be64_to_cpu(r2->rmap.rm_offset));
422 if (a <= b)
423 return 1;
424 return 0;
425}
426
427static const struct xfs_btree_ops xfs_rmapbt_ops = {
428 .rec_len = sizeof(struct xfs_rmap_rec),
429 .key_len = 2 * sizeof(struct xfs_rmap_key),
430
431 .dup_cursor = xfs_rmapbt_dup_cursor,
432 .set_root = xfs_rmapbt_set_root,
433 .alloc_block = xfs_rmapbt_alloc_block,
434 .free_block = xfs_rmapbt_free_block,
435 .get_minrecs = xfs_rmapbt_get_minrecs,
436 .get_maxrecs = xfs_rmapbt_get_maxrecs,
437 .init_key_from_rec = xfs_rmapbt_init_key_from_rec,
438 .init_high_key_from_rec = xfs_rmapbt_init_high_key_from_rec,
439 .init_rec_from_cur = xfs_rmapbt_init_rec_from_cur,
440 .init_ptr_from_cur = xfs_rmapbt_init_ptr_from_cur,
441 .key_diff = xfs_rmapbt_key_diff,
442 .buf_ops = &xfs_rmapbt_buf_ops,
443 .diff_two_keys = xfs_rmapbt_diff_two_keys,
444 .keys_inorder = xfs_rmapbt_keys_inorder,
445 .recs_inorder = xfs_rmapbt_recs_inorder,
446};
447
448static struct xfs_btree_cur *
449xfs_rmapbt_init_common(
450 struct xfs_mount *mp,
451 struct xfs_trans *tp,
452 struct xfs_perag *pag)
453{
454 struct xfs_btree_cur *cur;
455
456 /* Overlapping btree; 2 keys per pointer. */
457 cur = xfs_btree_alloc_cursor(mp, tp, XFS_BTNUM_RMAP,
458 mp->m_rmap_maxlevels, xfs_rmapbt_cur_cache);
459 cur->bc_flags = XFS_BTREE_CRC_BLOCKS | XFS_BTREE_OVERLAPPING;
460 cur->bc_statoff = XFS_STATS_CALC_INDEX(xs_rmap_2);
461 cur->bc_ops = &xfs_rmapbt_ops;
462
463 /* take a reference for the cursor */
464 atomic_inc(&pag->pag_ref);
465 cur->bc_ag.pag = pag;
466
467 return cur;
468}
469
470/* Create a new reverse mapping btree cursor. */
471struct xfs_btree_cur *
472xfs_rmapbt_init_cursor(
473 struct xfs_mount *mp,
474 struct xfs_trans *tp,
475 struct xfs_buf *agbp,
476 struct xfs_perag *pag)
477{
478 struct xfs_agf *agf = agbp->b_addr;
479 struct xfs_btree_cur *cur;
480
481 cur = xfs_rmapbt_init_common(mp, tp, pag);
482 cur->bc_nlevels = be32_to_cpu(agf->agf_levels[XFS_BTNUM_RMAP]);
483 cur->bc_ag.agbp = agbp;
484 return cur;
485}
486
487/* Create a new reverse mapping btree cursor with a fake root for staging. */
488struct xfs_btree_cur *
489xfs_rmapbt_stage_cursor(
490 struct xfs_mount *mp,
491 struct xbtree_afakeroot *afake,
492 struct xfs_perag *pag)
493{
494 struct xfs_btree_cur *cur;
495
496 cur = xfs_rmapbt_init_common(mp, NULL, pag);
497 xfs_btree_stage_afakeroot(cur, afake);
498 return cur;
499}
500
501/*
502 * Install a new reverse mapping btree root. Caller is responsible for
503 * invalidating and freeing the old btree blocks.
504 */
505void
506xfs_rmapbt_commit_staged_btree(
507 struct xfs_btree_cur *cur,
508 struct xfs_trans *tp,
509 struct xfs_buf *agbp)
510{
511 struct xfs_agf *agf = agbp->b_addr;
512 struct xbtree_afakeroot *afake = cur->bc_ag.afake;
513
514 ASSERT(cur->bc_flags & XFS_BTREE_STAGING);
515
516 agf->agf_roots[cur->bc_btnum] = cpu_to_be32(afake->af_root);
517 agf->agf_levels[cur->bc_btnum] = cpu_to_be32(afake->af_levels);
518 agf->agf_rmap_blocks = cpu_to_be32(afake->af_blocks);
519 xfs_alloc_log_agf(tp, agbp, XFS_AGF_ROOTS | XFS_AGF_LEVELS |
520 XFS_AGF_RMAP_BLOCKS);
521 xfs_btree_commit_afakeroot(cur, tp, agbp, &xfs_rmapbt_ops);
522}
523
524/* Calculate number of records in a reverse mapping btree block. */
525static inline unsigned int
526xfs_rmapbt_block_maxrecs(
527 unsigned int blocklen,
528 bool leaf)
529{
530 if (leaf)
531 return blocklen / sizeof(struct xfs_rmap_rec);
532 return blocklen /
533 (2 * sizeof(struct xfs_rmap_key) + sizeof(xfs_rmap_ptr_t));
534}
535
536/*
537 * Calculate number of records in an rmap btree block.
538 */
539int
540xfs_rmapbt_maxrecs(
541 int blocklen,
542 int leaf)
543{
544 blocklen -= XFS_RMAP_BLOCK_LEN;
545 return xfs_rmapbt_block_maxrecs(blocklen, leaf);
546}
547
548/* Compute the max possible height for reverse mapping btrees. */
549unsigned int
550xfs_rmapbt_maxlevels_ondisk(void)
551{
552 unsigned int minrecs[2];
553 unsigned int blocklen;
554
555 blocklen = XFS_MIN_CRC_BLOCKSIZE - XFS_BTREE_SBLOCK_CRC_LEN;
556
557 minrecs[0] = xfs_rmapbt_block_maxrecs(blocklen, true) / 2;
558 minrecs[1] = xfs_rmapbt_block_maxrecs(blocklen, false) / 2;
559
560 /*
561 * Compute the asymptotic maxlevels for an rmapbt on any reflink fs.
562 *
563 * On a reflink filesystem, each AG block can have up to 2^32 (per the
564 * refcount record format) owners, which means that theoretically we
565 * could face up to 2^64 rmap records. However, we're likely to run
566 * out of blocks in the AG long before that happens, which means that
567 * we must compute the max height based on what the btree will look
568 * like if it consumes almost all the blocks in the AG due to maximal
569 * sharing factor.
570 */
571 return xfs_btree_space_to_height(minrecs, XFS_MAX_CRC_AG_BLOCKS);
572}
573
574/* Compute the maximum height of an rmap btree. */
575void
576xfs_rmapbt_compute_maxlevels(
577 struct xfs_mount *mp)
578{
579 if (!xfs_has_rmapbt(mp)) {
580 mp->m_rmap_maxlevels = 0;
581 return;
582 }
583
584 if (xfs_has_reflink(mp)) {
585 /*
586 * Compute the asymptotic maxlevels for an rmap btree on a
587 * filesystem that supports reflink.
588 *
589 * On a reflink filesystem, each AG block can have up to 2^32
590 * (per the refcount record format) owners, which means that
591 * theoretically we could face up to 2^64 rmap records.
592 * However, we're likely to run out of blocks in the AG long
593 * before that happens, which means that we must compute the
594 * max height based on what the btree will look like if it
595 * consumes almost all the blocks in the AG due to maximal
596 * sharing factor.
597 */
598 mp->m_rmap_maxlevels = xfs_btree_space_to_height(mp->m_rmap_mnr,
599 mp->m_sb.sb_agblocks);
600 } else {
601 /*
602 * If there's no block sharing, compute the maximum rmapbt
603 * height assuming one rmap record per AG block.
604 */
605 mp->m_rmap_maxlevels = xfs_btree_compute_maxlevels(
606 mp->m_rmap_mnr, mp->m_sb.sb_agblocks);
607 }
608 ASSERT(mp->m_rmap_maxlevels <= xfs_rmapbt_maxlevels_ondisk());
609}
610
611/* Calculate the refcount btree size for some records. */
612xfs_extlen_t
613xfs_rmapbt_calc_size(
614 struct xfs_mount *mp,
615 unsigned long long len)
616{
617 return xfs_btree_calc_size(mp->m_rmap_mnr, len);
618}
619
620/*
621 * Calculate the maximum refcount btree size.
622 */
623xfs_extlen_t
624xfs_rmapbt_max_size(
625 struct xfs_mount *mp,
626 xfs_agblock_t agblocks)
627{
628 /* Bail out if we're uninitialized, which can happen in mkfs. */
629 if (mp->m_rmap_mxr[0] == 0)
630 return 0;
631
632 return xfs_rmapbt_calc_size(mp, agblocks);
633}
634
635/*
636 * Figure out how many blocks to reserve and how many are used by this btree.
637 */
638int
639xfs_rmapbt_calc_reserves(
640 struct xfs_mount *mp,
641 struct xfs_trans *tp,
642 struct xfs_perag *pag,
643 xfs_extlen_t *ask,
644 xfs_extlen_t *used)
645{
646 struct xfs_buf *agbp;
647 struct xfs_agf *agf;
648 xfs_agblock_t agblocks;
649 xfs_extlen_t tree_len;
650 int error;
651
652 if (!xfs_has_rmapbt(mp))
653 return 0;
654
655 error = xfs_alloc_read_agf(pag, tp, 0, &agbp);
656 if (error)
657 return error;
658
659 agf = agbp->b_addr;
660 agblocks = be32_to_cpu(agf->agf_length);
661 tree_len = be32_to_cpu(agf->agf_rmap_blocks);
662 xfs_trans_brelse(tp, agbp);
663
664 /*
665 * The log is permanently allocated, so the space it occupies will
666 * never be available for the kinds of things that would require btree
667 * expansion. We therefore can pretend the space isn't there.
668 */
669 if (xfs_ag_contains_log(mp, pag->pag_agno))
670 agblocks -= mp->m_sb.sb_logblocks;
671
672 /* Reserve 1% of the AG or enough for 1 block per record. */
673 *ask += max(agblocks / 100, xfs_rmapbt_max_size(mp, agblocks));
674 *used += tree_len;
675
676 return error;
677}
678
679int __init
680xfs_rmapbt_init_cur_cache(void)
681{
682 xfs_rmapbt_cur_cache = kmem_cache_create("xfs_rmapbt_cur",
683 xfs_btree_cur_sizeof(xfs_rmapbt_maxlevels_ondisk()),
684 0, 0, NULL);
685
686 if (!xfs_rmapbt_cur_cache)
687 return -ENOMEM;
688 return 0;
689}
690
691void
692xfs_rmapbt_destroy_cur_cache(void)
693{
694 kmem_cache_destroy(xfs_rmapbt_cur_cache);
695 xfs_rmapbt_cur_cache = NULL;
696}
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright (c) 2014 Red Hat, Inc.
4 * All Rights Reserved.
5 */
6#include "xfs.h"
7#include "xfs_fs.h"
8#include "xfs_shared.h"
9#include "xfs_format.h"
10#include "xfs_log_format.h"
11#include "xfs_trans_resv.h"
12#include "xfs_sb.h"
13#include "xfs_mount.h"
14#include "xfs_trans.h"
15#include "xfs_alloc.h"
16#include "xfs_btree.h"
17#include "xfs_rmap.h"
18#include "xfs_rmap_btree.h"
19#include "xfs_trace.h"
20#include "xfs_error.h"
21#include "xfs_extent_busy.h"
22#include "xfs_ag_resv.h"
23
24/*
25 * Reverse map btree.
26 *
27 * This is a per-ag tree used to track the owner(s) of a given extent. With
28 * reflink it is possible for there to be multiple owners, which is a departure
29 * from classic XFS. Owner records for data extents are inserted when the
30 * extent is mapped and removed when an extent is unmapped. Owner records for
31 * all other block types (i.e. metadata) are inserted when an extent is
32 * allocated and removed when an extent is freed. There can only be one owner
33 * of a metadata extent, usually an inode or some other metadata structure like
34 * an AG btree.
35 *
36 * The rmap btree is part of the free space management, so blocks for the tree
37 * are sourced from the agfl. Hence we need transaction reservation support for
38 * this tree so that the freelist is always large enough. This also impacts on
39 * the minimum space we need to leave free in the AG.
40 *
41 * The tree is ordered by [ag block, owner, offset]. This is a large key size,
42 * but it is the only way to enforce unique keys when a block can be owned by
43 * multiple files at any offset. There's no need to order/search by extent
44 * size for online updating/management of the tree. It is intended that most
45 * reverse lookups will be to find the owner(s) of a particular block, or to
46 * try to recover tree and file data from corrupt primary metadata.
47 */
48
49static struct xfs_btree_cur *
50xfs_rmapbt_dup_cursor(
51 struct xfs_btree_cur *cur)
52{
53 return xfs_rmapbt_init_cursor(cur->bc_mp, cur->bc_tp,
54 cur->bc_private.a.agbp, cur->bc_private.a.agno);
55}
56
57STATIC void
58xfs_rmapbt_set_root(
59 struct xfs_btree_cur *cur,
60 union xfs_btree_ptr *ptr,
61 int inc)
62{
63 struct xfs_buf *agbp = cur->bc_private.a.agbp;
64 struct xfs_agf *agf = XFS_BUF_TO_AGF(agbp);
65 xfs_agnumber_t seqno = be32_to_cpu(agf->agf_seqno);
66 int btnum = cur->bc_btnum;
67 struct xfs_perag *pag = xfs_perag_get(cur->bc_mp, seqno);
68
69 ASSERT(ptr->s != 0);
70
71 agf->agf_roots[btnum] = ptr->s;
72 be32_add_cpu(&agf->agf_levels[btnum], inc);
73 pag->pagf_levels[btnum] += inc;
74 xfs_perag_put(pag);
75
76 xfs_alloc_log_agf(cur->bc_tp, agbp, XFS_AGF_ROOTS | XFS_AGF_LEVELS);
77}
78
79STATIC int
80xfs_rmapbt_alloc_block(
81 struct xfs_btree_cur *cur,
82 union xfs_btree_ptr *start,
83 union xfs_btree_ptr *new,
84 int *stat)
85{
86 struct xfs_buf *agbp = cur->bc_private.a.agbp;
87 struct xfs_agf *agf = XFS_BUF_TO_AGF(agbp);
88 int error;
89 xfs_agblock_t bno;
90
91 /* Allocate the new block from the freelist. If we can't, give up. */
92 error = xfs_alloc_get_freelist(cur->bc_tp, cur->bc_private.a.agbp,
93 &bno, 1);
94 if (error)
95 return error;
96
97 trace_xfs_rmapbt_alloc_block(cur->bc_mp, cur->bc_private.a.agno,
98 bno, 1);
99 if (bno == NULLAGBLOCK) {
100 *stat = 0;
101 return 0;
102 }
103
104 xfs_extent_busy_reuse(cur->bc_mp, cur->bc_private.a.agno, bno, 1,
105 false);
106
107 xfs_trans_agbtree_delta(cur->bc_tp, 1);
108 new->s = cpu_to_be32(bno);
109 be32_add_cpu(&agf->agf_rmap_blocks, 1);
110 xfs_alloc_log_agf(cur->bc_tp, agbp, XFS_AGF_RMAP_BLOCKS);
111
112 xfs_ag_resv_rmapbt_alloc(cur->bc_mp, cur->bc_private.a.agno);
113
114 *stat = 1;
115 return 0;
116}
117
118STATIC int
119xfs_rmapbt_free_block(
120 struct xfs_btree_cur *cur,
121 struct xfs_buf *bp)
122{
123 struct xfs_buf *agbp = cur->bc_private.a.agbp;
124 struct xfs_agf *agf = XFS_BUF_TO_AGF(agbp);
125 xfs_agblock_t bno;
126 int error;
127
128 bno = xfs_daddr_to_agbno(cur->bc_mp, XFS_BUF_ADDR(bp));
129 trace_xfs_rmapbt_free_block(cur->bc_mp, cur->bc_private.a.agno,
130 bno, 1);
131 be32_add_cpu(&agf->agf_rmap_blocks, -1);
132 xfs_alloc_log_agf(cur->bc_tp, agbp, XFS_AGF_RMAP_BLOCKS);
133 error = xfs_alloc_put_freelist(cur->bc_tp, agbp, NULL, bno, 1);
134 if (error)
135 return error;
136
137 xfs_extent_busy_insert(cur->bc_tp, be32_to_cpu(agf->agf_seqno), bno, 1,
138 XFS_EXTENT_BUSY_SKIP_DISCARD);
139 xfs_trans_agbtree_delta(cur->bc_tp, -1);
140
141 xfs_ag_resv_rmapbt_free(cur->bc_mp, cur->bc_private.a.agno);
142
143 return 0;
144}
145
146STATIC int
147xfs_rmapbt_get_minrecs(
148 struct xfs_btree_cur *cur,
149 int level)
150{
151 return cur->bc_mp->m_rmap_mnr[level != 0];
152}
153
154STATIC int
155xfs_rmapbt_get_maxrecs(
156 struct xfs_btree_cur *cur,
157 int level)
158{
159 return cur->bc_mp->m_rmap_mxr[level != 0];
160}
161
162STATIC void
163xfs_rmapbt_init_key_from_rec(
164 union xfs_btree_key *key,
165 union xfs_btree_rec *rec)
166{
167 key->rmap.rm_startblock = rec->rmap.rm_startblock;
168 key->rmap.rm_owner = rec->rmap.rm_owner;
169 key->rmap.rm_offset = rec->rmap.rm_offset;
170}
171
172/*
173 * The high key for a reverse mapping record can be computed by shifting
174 * the startblock and offset to the highest value that would still map
175 * to that record. In practice this means that we add blockcount-1 to
176 * the startblock for all records, and if the record is for a data/attr
177 * fork mapping, we add blockcount-1 to the offset too.
178 */
179STATIC void
180xfs_rmapbt_init_high_key_from_rec(
181 union xfs_btree_key *key,
182 union xfs_btree_rec *rec)
183{
184 uint64_t off;
185 int adj;
186
187 adj = be32_to_cpu(rec->rmap.rm_blockcount) - 1;
188
189 key->rmap.rm_startblock = rec->rmap.rm_startblock;
190 be32_add_cpu(&key->rmap.rm_startblock, adj);
191 key->rmap.rm_owner = rec->rmap.rm_owner;
192 key->rmap.rm_offset = rec->rmap.rm_offset;
193 if (XFS_RMAP_NON_INODE_OWNER(be64_to_cpu(rec->rmap.rm_owner)) ||
194 XFS_RMAP_IS_BMBT_BLOCK(be64_to_cpu(rec->rmap.rm_offset)))
195 return;
196 off = be64_to_cpu(key->rmap.rm_offset);
197 off = (XFS_RMAP_OFF(off) + adj) | (off & ~XFS_RMAP_OFF_MASK);
198 key->rmap.rm_offset = cpu_to_be64(off);
199}
200
201STATIC void
202xfs_rmapbt_init_rec_from_cur(
203 struct xfs_btree_cur *cur,
204 union xfs_btree_rec *rec)
205{
206 rec->rmap.rm_startblock = cpu_to_be32(cur->bc_rec.r.rm_startblock);
207 rec->rmap.rm_blockcount = cpu_to_be32(cur->bc_rec.r.rm_blockcount);
208 rec->rmap.rm_owner = cpu_to_be64(cur->bc_rec.r.rm_owner);
209 rec->rmap.rm_offset = cpu_to_be64(
210 xfs_rmap_irec_offset_pack(&cur->bc_rec.r));
211}
212
213STATIC void
214xfs_rmapbt_init_ptr_from_cur(
215 struct xfs_btree_cur *cur,
216 union xfs_btree_ptr *ptr)
217{
218 struct xfs_agf *agf = XFS_BUF_TO_AGF(cur->bc_private.a.agbp);
219
220 ASSERT(cur->bc_private.a.agno == be32_to_cpu(agf->agf_seqno));
221
222 ptr->s = agf->agf_roots[cur->bc_btnum];
223}
224
225STATIC int64_t
226xfs_rmapbt_key_diff(
227 struct xfs_btree_cur *cur,
228 union xfs_btree_key *key)
229{
230 struct xfs_rmap_irec *rec = &cur->bc_rec.r;
231 struct xfs_rmap_key *kp = &key->rmap;
232 __u64 x, y;
233 int64_t d;
234
235 d = (int64_t)be32_to_cpu(kp->rm_startblock) - rec->rm_startblock;
236 if (d)
237 return d;
238
239 x = be64_to_cpu(kp->rm_owner);
240 y = rec->rm_owner;
241 if (x > y)
242 return 1;
243 else if (y > x)
244 return -1;
245
246 x = XFS_RMAP_OFF(be64_to_cpu(kp->rm_offset));
247 y = rec->rm_offset;
248 if (x > y)
249 return 1;
250 else if (y > x)
251 return -1;
252 return 0;
253}
254
255STATIC int64_t
256xfs_rmapbt_diff_two_keys(
257 struct xfs_btree_cur *cur,
258 union xfs_btree_key *k1,
259 union xfs_btree_key *k2)
260{
261 struct xfs_rmap_key *kp1 = &k1->rmap;
262 struct xfs_rmap_key *kp2 = &k2->rmap;
263 int64_t d;
264 __u64 x, y;
265
266 d = (int64_t)be32_to_cpu(kp1->rm_startblock) -
267 be32_to_cpu(kp2->rm_startblock);
268 if (d)
269 return d;
270
271 x = be64_to_cpu(kp1->rm_owner);
272 y = be64_to_cpu(kp2->rm_owner);
273 if (x > y)
274 return 1;
275 else if (y > x)
276 return -1;
277
278 x = XFS_RMAP_OFF(be64_to_cpu(kp1->rm_offset));
279 y = XFS_RMAP_OFF(be64_to_cpu(kp2->rm_offset));
280 if (x > y)
281 return 1;
282 else if (y > x)
283 return -1;
284 return 0;
285}
286
287static xfs_failaddr_t
288xfs_rmapbt_verify(
289 struct xfs_buf *bp)
290{
291 struct xfs_mount *mp = bp->b_mount;
292 struct xfs_btree_block *block = XFS_BUF_TO_BLOCK(bp);
293 struct xfs_perag *pag = bp->b_pag;
294 xfs_failaddr_t fa;
295 unsigned int level;
296
297 /*
298 * magic number and level verification
299 *
300 * During growfs operations, we can't verify the exact level or owner as
301 * the perag is not fully initialised and hence not attached to the
302 * buffer. In this case, check against the maximum tree depth.
303 *
304 * Similarly, during log recovery we will have a perag structure
305 * attached, but the agf information will not yet have been initialised
306 * from the on disk AGF. Again, we can only check against maximum limits
307 * in this case.
308 */
309 if (!xfs_verify_magic(bp, block->bb_magic))
310 return __this_address;
311
312 if (!xfs_sb_version_hasrmapbt(&mp->m_sb))
313 return __this_address;
314 fa = xfs_btree_sblock_v5hdr_verify(bp);
315 if (fa)
316 return fa;
317
318 level = be16_to_cpu(block->bb_level);
319 if (pag && pag->pagf_init) {
320 if (level >= pag->pagf_levels[XFS_BTNUM_RMAPi])
321 return __this_address;
322 } else if (level >= mp->m_rmap_maxlevels)
323 return __this_address;
324
325 return xfs_btree_sblock_verify(bp, mp->m_rmap_mxr[level != 0]);
326}
327
328static void
329xfs_rmapbt_read_verify(
330 struct xfs_buf *bp)
331{
332 xfs_failaddr_t fa;
333
334 if (!xfs_btree_sblock_verify_crc(bp))
335 xfs_verifier_error(bp, -EFSBADCRC, __this_address);
336 else {
337 fa = xfs_rmapbt_verify(bp);
338 if (fa)
339 xfs_verifier_error(bp, -EFSCORRUPTED, fa);
340 }
341
342 if (bp->b_error)
343 trace_xfs_btree_corrupt(bp, _RET_IP_);
344}
345
346static void
347xfs_rmapbt_write_verify(
348 struct xfs_buf *bp)
349{
350 xfs_failaddr_t fa;
351
352 fa = xfs_rmapbt_verify(bp);
353 if (fa) {
354 trace_xfs_btree_corrupt(bp, _RET_IP_);
355 xfs_verifier_error(bp, -EFSCORRUPTED, fa);
356 return;
357 }
358 xfs_btree_sblock_calc_crc(bp);
359
360}
361
362const struct xfs_buf_ops xfs_rmapbt_buf_ops = {
363 .name = "xfs_rmapbt",
364 .magic = { 0, cpu_to_be32(XFS_RMAP_CRC_MAGIC) },
365 .verify_read = xfs_rmapbt_read_verify,
366 .verify_write = xfs_rmapbt_write_verify,
367 .verify_struct = xfs_rmapbt_verify,
368};
369
370STATIC int
371xfs_rmapbt_keys_inorder(
372 struct xfs_btree_cur *cur,
373 union xfs_btree_key *k1,
374 union xfs_btree_key *k2)
375{
376 uint32_t x;
377 uint32_t y;
378 uint64_t a;
379 uint64_t b;
380
381 x = be32_to_cpu(k1->rmap.rm_startblock);
382 y = be32_to_cpu(k2->rmap.rm_startblock);
383 if (x < y)
384 return 1;
385 else if (x > y)
386 return 0;
387 a = be64_to_cpu(k1->rmap.rm_owner);
388 b = be64_to_cpu(k2->rmap.rm_owner);
389 if (a < b)
390 return 1;
391 else if (a > b)
392 return 0;
393 a = XFS_RMAP_OFF(be64_to_cpu(k1->rmap.rm_offset));
394 b = XFS_RMAP_OFF(be64_to_cpu(k2->rmap.rm_offset));
395 if (a <= b)
396 return 1;
397 return 0;
398}
399
400STATIC int
401xfs_rmapbt_recs_inorder(
402 struct xfs_btree_cur *cur,
403 union xfs_btree_rec *r1,
404 union xfs_btree_rec *r2)
405{
406 uint32_t x;
407 uint32_t y;
408 uint64_t a;
409 uint64_t b;
410
411 x = be32_to_cpu(r1->rmap.rm_startblock);
412 y = be32_to_cpu(r2->rmap.rm_startblock);
413 if (x < y)
414 return 1;
415 else if (x > y)
416 return 0;
417 a = be64_to_cpu(r1->rmap.rm_owner);
418 b = be64_to_cpu(r2->rmap.rm_owner);
419 if (a < b)
420 return 1;
421 else if (a > b)
422 return 0;
423 a = XFS_RMAP_OFF(be64_to_cpu(r1->rmap.rm_offset));
424 b = XFS_RMAP_OFF(be64_to_cpu(r2->rmap.rm_offset));
425 if (a <= b)
426 return 1;
427 return 0;
428}
429
430static const struct xfs_btree_ops xfs_rmapbt_ops = {
431 .rec_len = sizeof(struct xfs_rmap_rec),
432 .key_len = 2 * sizeof(struct xfs_rmap_key),
433
434 .dup_cursor = xfs_rmapbt_dup_cursor,
435 .set_root = xfs_rmapbt_set_root,
436 .alloc_block = xfs_rmapbt_alloc_block,
437 .free_block = xfs_rmapbt_free_block,
438 .get_minrecs = xfs_rmapbt_get_minrecs,
439 .get_maxrecs = xfs_rmapbt_get_maxrecs,
440 .init_key_from_rec = xfs_rmapbt_init_key_from_rec,
441 .init_high_key_from_rec = xfs_rmapbt_init_high_key_from_rec,
442 .init_rec_from_cur = xfs_rmapbt_init_rec_from_cur,
443 .init_ptr_from_cur = xfs_rmapbt_init_ptr_from_cur,
444 .key_diff = xfs_rmapbt_key_diff,
445 .buf_ops = &xfs_rmapbt_buf_ops,
446 .diff_two_keys = xfs_rmapbt_diff_two_keys,
447 .keys_inorder = xfs_rmapbt_keys_inorder,
448 .recs_inorder = xfs_rmapbt_recs_inorder,
449};
450
451/*
452 * Allocate a new allocation btree cursor.
453 */
454struct xfs_btree_cur *
455xfs_rmapbt_init_cursor(
456 struct xfs_mount *mp,
457 struct xfs_trans *tp,
458 struct xfs_buf *agbp,
459 xfs_agnumber_t agno)
460{
461 struct xfs_agf *agf = XFS_BUF_TO_AGF(agbp);
462 struct xfs_btree_cur *cur;
463
464 cur = kmem_zone_zalloc(xfs_btree_cur_zone, KM_NOFS);
465 cur->bc_tp = tp;
466 cur->bc_mp = mp;
467 /* Overlapping btree; 2 keys per pointer. */
468 cur->bc_btnum = XFS_BTNUM_RMAP;
469 cur->bc_flags = XFS_BTREE_CRC_BLOCKS | XFS_BTREE_OVERLAPPING;
470 cur->bc_blocklog = mp->m_sb.sb_blocklog;
471 cur->bc_ops = &xfs_rmapbt_ops;
472 cur->bc_nlevels = be32_to_cpu(agf->agf_levels[XFS_BTNUM_RMAP]);
473 cur->bc_statoff = XFS_STATS_CALC_INDEX(xs_rmap_2);
474
475 cur->bc_private.a.agbp = agbp;
476 cur->bc_private.a.agno = agno;
477
478 return cur;
479}
480
481/*
482 * Calculate number of records in an rmap btree block.
483 */
484int
485xfs_rmapbt_maxrecs(
486 int blocklen,
487 int leaf)
488{
489 blocklen -= XFS_RMAP_BLOCK_LEN;
490
491 if (leaf)
492 return blocklen / sizeof(struct xfs_rmap_rec);
493 return blocklen /
494 (2 * sizeof(struct xfs_rmap_key) + sizeof(xfs_rmap_ptr_t));
495}
496
497/* Compute the maximum height of an rmap btree. */
498void
499xfs_rmapbt_compute_maxlevels(
500 struct xfs_mount *mp)
501{
502 /*
503 * On a non-reflink filesystem, the maximum number of rmap
504 * records is the number of blocks in the AG, hence the max
505 * rmapbt height is log_$maxrecs($agblocks). However, with
506 * reflink each AG block can have up to 2^32 (per the refcount
507 * record format) owners, which means that theoretically we
508 * could face up to 2^64 rmap records.
509 *
510 * That effectively means that the max rmapbt height must be
511 * XFS_BTREE_MAXLEVELS. "Fortunately" we'll run out of AG
512 * blocks to feed the rmapbt long before the rmapbt reaches
513 * maximum height. The reflink code uses ag_resv_critical to
514 * disallow reflinking when less than 10% of the per-AG metadata
515 * block reservation since the fallback is a regular file copy.
516 */
517 if (xfs_sb_version_hasreflink(&mp->m_sb))
518 mp->m_rmap_maxlevels = XFS_BTREE_MAXLEVELS;
519 else
520 mp->m_rmap_maxlevels = xfs_btree_compute_maxlevels(
521 mp->m_rmap_mnr, mp->m_sb.sb_agblocks);
522}
523
524/* Calculate the refcount btree size for some records. */
525xfs_extlen_t
526xfs_rmapbt_calc_size(
527 struct xfs_mount *mp,
528 unsigned long long len)
529{
530 return xfs_btree_calc_size(mp->m_rmap_mnr, len);
531}
532
533/*
534 * Calculate the maximum refcount btree size.
535 */
536xfs_extlen_t
537xfs_rmapbt_max_size(
538 struct xfs_mount *mp,
539 xfs_agblock_t agblocks)
540{
541 /* Bail out if we're uninitialized, which can happen in mkfs. */
542 if (mp->m_rmap_mxr[0] == 0)
543 return 0;
544
545 return xfs_rmapbt_calc_size(mp, agblocks);
546}
547
548/*
549 * Figure out how many blocks to reserve and how many are used by this btree.
550 */
551int
552xfs_rmapbt_calc_reserves(
553 struct xfs_mount *mp,
554 struct xfs_trans *tp,
555 xfs_agnumber_t agno,
556 xfs_extlen_t *ask,
557 xfs_extlen_t *used)
558{
559 struct xfs_buf *agbp;
560 struct xfs_agf *agf;
561 xfs_agblock_t agblocks;
562 xfs_extlen_t tree_len;
563 int error;
564
565 if (!xfs_sb_version_hasrmapbt(&mp->m_sb))
566 return 0;
567
568 error = xfs_alloc_read_agf(mp, tp, agno, 0, &agbp);
569 if (error)
570 return error;
571
572 agf = XFS_BUF_TO_AGF(agbp);
573 agblocks = be32_to_cpu(agf->agf_length);
574 tree_len = be32_to_cpu(agf->agf_rmap_blocks);
575 xfs_trans_brelse(tp, agbp);
576
577 /*
578 * The log is permanently allocated, so the space it occupies will
579 * never be available for the kinds of things that would require btree
580 * expansion. We therefore can pretend the space isn't there.
581 */
582 if (mp->m_sb.sb_logstart &&
583 XFS_FSB_TO_AGNO(mp, mp->m_sb.sb_logstart) == agno)
584 agblocks -= mp->m_sb.sb_logblocks;
585
586 /* Reserve 1% of the AG or enough for 1 block per record. */
587 *ask += max(agblocks / 100, xfs_rmapbt_max_size(mp, agblocks));
588 *used += tree_len;
589
590 return error;
591}