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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/*
2 * Copyright (c) 2014 Red Hat, 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_sb.h"
26#include "xfs_mount.h"
27#include "xfs_defer.h"
28#include "xfs_inode.h"
29#include "xfs_trans.h"
30#include "xfs_alloc.h"
31#include "xfs_btree.h"
32#include "xfs_rmap.h"
33#include "xfs_rmap_btree.h"
34#include "xfs_trace.h"
35#include "xfs_cksum.h"
36#include "xfs_error.h"
37#include "xfs_extent_busy.h"
38#include "xfs_ag_resv.h"
39
40/*
41 * Reverse map btree.
42 *
43 * This is a per-ag tree used to track the owner(s) of a given extent. With
44 * reflink it is possible for there to be multiple owners, which is a departure
45 * from classic XFS. Owner records for data extents are inserted when the
46 * extent is mapped and removed when an extent is unmapped. Owner records for
47 * all other block types (i.e. metadata) are inserted when an extent is
48 * allocated and removed when an extent is freed. There can only be one owner
49 * of a metadata extent, usually an inode or some other metadata structure like
50 * an AG btree.
51 *
52 * The rmap btree is part of the free space management, so blocks for the tree
53 * are sourced from the agfl. Hence we need transaction reservation support for
54 * this tree so that the freelist is always large enough. This also impacts on
55 * the minimum space we need to leave free in the AG.
56 *
57 * The tree is ordered by [ag block, owner, offset]. This is a large key size,
58 * but it is the only way to enforce unique keys when a block can be owned by
59 * multiple files at any offset. There's no need to order/search by extent
60 * size for online updating/management of the tree. It is intended that most
61 * reverse lookups will be to find the owner(s) of a particular block, or to
62 * try to recover tree and file data from corrupt primary metadata.
63 */
64
65static struct xfs_btree_cur *
66xfs_rmapbt_dup_cursor(
67 struct xfs_btree_cur *cur)
68{
69 return xfs_rmapbt_init_cursor(cur->bc_mp, cur->bc_tp,
70 cur->bc_private.a.agbp, cur->bc_private.a.agno);
71}
72
73STATIC void
74xfs_rmapbt_set_root(
75 struct xfs_btree_cur *cur,
76 union xfs_btree_ptr *ptr,
77 int inc)
78{
79 struct xfs_buf *agbp = cur->bc_private.a.agbp;
80 struct xfs_agf *agf = XFS_BUF_TO_AGF(agbp);
81 xfs_agnumber_t seqno = be32_to_cpu(agf->agf_seqno);
82 int btnum = cur->bc_btnum;
83 struct xfs_perag *pag = xfs_perag_get(cur->bc_mp, seqno);
84
85 ASSERT(ptr->s != 0);
86
87 agf->agf_roots[btnum] = ptr->s;
88 be32_add_cpu(&agf->agf_levels[btnum], inc);
89 pag->pagf_levels[btnum] += inc;
90 xfs_perag_put(pag);
91
92 xfs_alloc_log_agf(cur->bc_tp, agbp, XFS_AGF_ROOTS | XFS_AGF_LEVELS);
93}
94
95STATIC int
96xfs_rmapbt_alloc_block(
97 struct xfs_btree_cur *cur,
98 union xfs_btree_ptr *start,
99 union xfs_btree_ptr *new,
100 int *stat)
101{
102 struct xfs_buf *agbp = cur->bc_private.a.agbp;
103 struct xfs_agf *agf = XFS_BUF_TO_AGF(agbp);
104 int error;
105 xfs_agblock_t bno;
106
107 XFS_BTREE_TRACE_CURSOR(cur, XBT_ENTRY);
108
109 /* Allocate the new block from the freelist. If we can't, give up. */
110 error = xfs_alloc_get_freelist(cur->bc_tp, cur->bc_private.a.agbp,
111 &bno, 1);
112 if (error) {
113 XFS_BTREE_TRACE_CURSOR(cur, XBT_ERROR);
114 return error;
115 }
116
117 trace_xfs_rmapbt_alloc_block(cur->bc_mp, cur->bc_private.a.agno,
118 bno, 1);
119 if (bno == NULLAGBLOCK) {
120 XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
121 *stat = 0;
122 return 0;
123 }
124
125 xfs_extent_busy_reuse(cur->bc_mp, cur->bc_private.a.agno, bno, 1,
126 false);
127
128 xfs_trans_agbtree_delta(cur->bc_tp, 1);
129 new->s = cpu_to_be32(bno);
130 be32_add_cpu(&agf->agf_rmap_blocks, 1);
131 xfs_alloc_log_agf(cur->bc_tp, agbp, XFS_AGF_RMAP_BLOCKS);
132
133 XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
134 *stat = 1;
135 return 0;
136}
137
138STATIC int
139xfs_rmapbt_free_block(
140 struct xfs_btree_cur *cur,
141 struct xfs_buf *bp)
142{
143 struct xfs_buf *agbp = cur->bc_private.a.agbp;
144 struct xfs_agf *agf = XFS_BUF_TO_AGF(agbp);
145 xfs_agblock_t bno;
146 int error;
147
148 bno = xfs_daddr_to_agbno(cur->bc_mp, XFS_BUF_ADDR(bp));
149 trace_xfs_rmapbt_free_block(cur->bc_mp, cur->bc_private.a.agno,
150 bno, 1);
151 be32_add_cpu(&agf->agf_rmap_blocks, -1);
152 xfs_alloc_log_agf(cur->bc_tp, agbp, XFS_AGF_RMAP_BLOCKS);
153 error = xfs_alloc_put_freelist(cur->bc_tp, agbp, NULL, bno, 1);
154 if (error)
155 return error;
156
157 xfs_extent_busy_insert(cur->bc_tp, be32_to_cpu(agf->agf_seqno), bno, 1,
158 XFS_EXTENT_BUSY_SKIP_DISCARD);
159 xfs_trans_agbtree_delta(cur->bc_tp, -1);
160
161 return 0;
162}
163
164STATIC int
165xfs_rmapbt_get_minrecs(
166 struct xfs_btree_cur *cur,
167 int level)
168{
169 return cur->bc_mp->m_rmap_mnr[level != 0];
170}
171
172STATIC int
173xfs_rmapbt_get_maxrecs(
174 struct xfs_btree_cur *cur,
175 int level)
176{
177 return cur->bc_mp->m_rmap_mxr[level != 0];
178}
179
180STATIC void
181xfs_rmapbt_init_key_from_rec(
182 union xfs_btree_key *key,
183 union xfs_btree_rec *rec)
184{
185 key->rmap.rm_startblock = rec->rmap.rm_startblock;
186 key->rmap.rm_owner = rec->rmap.rm_owner;
187 key->rmap.rm_offset = rec->rmap.rm_offset;
188}
189
190/*
191 * The high key for a reverse mapping record can be computed by shifting
192 * the startblock and offset to the highest value that would still map
193 * to that record. In practice this means that we add blockcount-1 to
194 * the startblock for all records, and if the record is for a data/attr
195 * fork mapping, we add blockcount-1 to the offset too.
196 */
197STATIC void
198xfs_rmapbt_init_high_key_from_rec(
199 union xfs_btree_key *key,
200 union xfs_btree_rec *rec)
201{
202 __uint64_t off;
203 int adj;
204
205 adj = be32_to_cpu(rec->rmap.rm_blockcount) - 1;
206
207 key->rmap.rm_startblock = rec->rmap.rm_startblock;
208 be32_add_cpu(&key->rmap.rm_startblock, adj);
209 key->rmap.rm_owner = rec->rmap.rm_owner;
210 key->rmap.rm_offset = rec->rmap.rm_offset;
211 if (XFS_RMAP_NON_INODE_OWNER(be64_to_cpu(rec->rmap.rm_owner)) ||
212 XFS_RMAP_IS_BMBT_BLOCK(be64_to_cpu(rec->rmap.rm_offset)))
213 return;
214 off = be64_to_cpu(key->rmap.rm_offset);
215 off = (XFS_RMAP_OFF(off) + adj) | (off & ~XFS_RMAP_OFF_MASK);
216 key->rmap.rm_offset = cpu_to_be64(off);
217}
218
219STATIC void
220xfs_rmapbt_init_rec_from_cur(
221 struct xfs_btree_cur *cur,
222 union xfs_btree_rec *rec)
223{
224 rec->rmap.rm_startblock = cpu_to_be32(cur->bc_rec.r.rm_startblock);
225 rec->rmap.rm_blockcount = cpu_to_be32(cur->bc_rec.r.rm_blockcount);
226 rec->rmap.rm_owner = cpu_to_be64(cur->bc_rec.r.rm_owner);
227 rec->rmap.rm_offset = cpu_to_be64(
228 xfs_rmap_irec_offset_pack(&cur->bc_rec.r));
229}
230
231STATIC void
232xfs_rmapbt_init_ptr_from_cur(
233 struct xfs_btree_cur *cur,
234 union xfs_btree_ptr *ptr)
235{
236 struct xfs_agf *agf = XFS_BUF_TO_AGF(cur->bc_private.a.agbp);
237
238 ASSERT(cur->bc_private.a.agno == be32_to_cpu(agf->agf_seqno));
239 ASSERT(agf->agf_roots[cur->bc_btnum] != 0);
240
241 ptr->s = agf->agf_roots[cur->bc_btnum];
242}
243
244STATIC __int64_t
245xfs_rmapbt_key_diff(
246 struct xfs_btree_cur *cur,
247 union xfs_btree_key *key)
248{
249 struct xfs_rmap_irec *rec = &cur->bc_rec.r;
250 struct xfs_rmap_key *kp = &key->rmap;
251 __u64 x, y;
252 __int64_t d;
253
254 d = (__int64_t)be32_to_cpu(kp->rm_startblock) - rec->rm_startblock;
255 if (d)
256 return d;
257
258 x = be64_to_cpu(kp->rm_owner);
259 y = rec->rm_owner;
260 if (x > y)
261 return 1;
262 else if (y > x)
263 return -1;
264
265 x = XFS_RMAP_OFF(be64_to_cpu(kp->rm_offset));
266 y = rec->rm_offset;
267 if (x > y)
268 return 1;
269 else if (y > x)
270 return -1;
271 return 0;
272}
273
274STATIC __int64_t
275xfs_rmapbt_diff_two_keys(
276 struct xfs_btree_cur *cur,
277 union xfs_btree_key *k1,
278 union xfs_btree_key *k2)
279{
280 struct xfs_rmap_key *kp1 = &k1->rmap;
281 struct xfs_rmap_key *kp2 = &k2->rmap;
282 __int64_t d;
283 __u64 x, y;
284
285 d = (__int64_t)be32_to_cpu(kp1->rm_startblock) -
286 be32_to_cpu(kp2->rm_startblock);
287 if (d)
288 return d;
289
290 x = be64_to_cpu(kp1->rm_owner);
291 y = be64_to_cpu(kp2->rm_owner);
292 if (x > y)
293 return 1;
294 else if (y > x)
295 return -1;
296
297 x = XFS_RMAP_OFF(be64_to_cpu(kp1->rm_offset));
298 y = XFS_RMAP_OFF(be64_to_cpu(kp2->rm_offset));
299 if (x > y)
300 return 1;
301 else if (y > x)
302 return -1;
303 return 0;
304}
305
306static bool
307xfs_rmapbt_verify(
308 struct xfs_buf *bp)
309{
310 struct xfs_mount *mp = bp->b_target->bt_mount;
311 struct xfs_btree_block *block = XFS_BUF_TO_BLOCK(bp);
312 struct xfs_perag *pag = bp->b_pag;
313 unsigned int level;
314
315 /*
316 * magic number and level verification
317 *
318 * During growfs operations, we can't verify the exact level or owner as
319 * the perag is not fully initialised and hence not attached to the
320 * buffer. In this case, check against the maximum tree depth.
321 *
322 * Similarly, during log recovery we will have a perag structure
323 * attached, but the agf information will not yet have been initialised
324 * from the on disk AGF. Again, we can only check against maximum limits
325 * in this case.
326 */
327 if (block->bb_magic != cpu_to_be32(XFS_RMAP_CRC_MAGIC))
328 return false;
329
330 if (!xfs_sb_version_hasrmapbt(&mp->m_sb))
331 return false;
332 if (!xfs_btree_sblock_v5hdr_verify(bp))
333 return false;
334
335 level = be16_to_cpu(block->bb_level);
336 if (pag && pag->pagf_init) {
337 if (level >= pag->pagf_levels[XFS_BTNUM_RMAPi])
338 return false;
339 } else if (level >= mp->m_rmap_maxlevels)
340 return false;
341
342 return xfs_btree_sblock_verify(bp, mp->m_rmap_mxr[level != 0]);
343}
344
345static void
346xfs_rmapbt_read_verify(
347 struct xfs_buf *bp)
348{
349 if (!xfs_btree_sblock_verify_crc(bp))
350 xfs_buf_ioerror(bp, -EFSBADCRC);
351 else if (!xfs_rmapbt_verify(bp))
352 xfs_buf_ioerror(bp, -EFSCORRUPTED);
353
354 if (bp->b_error) {
355 trace_xfs_btree_corrupt(bp, _RET_IP_);
356 xfs_verifier_error(bp);
357 }
358}
359
360static void
361xfs_rmapbt_write_verify(
362 struct xfs_buf *bp)
363{
364 if (!xfs_rmapbt_verify(bp)) {
365 trace_xfs_btree_corrupt(bp, _RET_IP_);
366 xfs_buf_ioerror(bp, -EFSCORRUPTED);
367 xfs_verifier_error(bp);
368 return;
369 }
370 xfs_btree_sblock_calc_crc(bp);
371
372}
373
374const struct xfs_buf_ops xfs_rmapbt_buf_ops = {
375 .name = "xfs_rmapbt",
376 .verify_read = xfs_rmapbt_read_verify,
377 .verify_write = xfs_rmapbt_write_verify,
378};
379
380#if defined(DEBUG) || defined(XFS_WARN)
381STATIC int
382xfs_rmapbt_keys_inorder(
383 struct xfs_btree_cur *cur,
384 union xfs_btree_key *k1,
385 union xfs_btree_key *k2)
386{
387 __uint32_t x;
388 __uint32_t y;
389 __uint64_t a;
390 __uint64_t b;
391
392 x = be32_to_cpu(k1->rmap.rm_startblock);
393 y = be32_to_cpu(k2->rmap.rm_startblock);
394 if (x < y)
395 return 1;
396 else if (x > y)
397 return 0;
398 a = be64_to_cpu(k1->rmap.rm_owner);
399 b = be64_to_cpu(k2->rmap.rm_owner);
400 if (a < b)
401 return 1;
402 else if (a > b)
403 return 0;
404 a = XFS_RMAP_OFF(be64_to_cpu(k1->rmap.rm_offset));
405 b = XFS_RMAP_OFF(be64_to_cpu(k2->rmap.rm_offset));
406 if (a <= b)
407 return 1;
408 return 0;
409}
410
411STATIC int
412xfs_rmapbt_recs_inorder(
413 struct xfs_btree_cur *cur,
414 union xfs_btree_rec *r1,
415 union xfs_btree_rec *r2)
416{
417 __uint32_t x;
418 __uint32_t y;
419 __uint64_t a;
420 __uint64_t b;
421
422 x = be32_to_cpu(r1->rmap.rm_startblock);
423 y = be32_to_cpu(r2->rmap.rm_startblock);
424 if (x < y)
425 return 1;
426 else if (x > y)
427 return 0;
428 a = be64_to_cpu(r1->rmap.rm_owner);
429 b = be64_to_cpu(r2->rmap.rm_owner);
430 if (a < b)
431 return 1;
432 else if (a > b)
433 return 0;
434 a = XFS_RMAP_OFF(be64_to_cpu(r1->rmap.rm_offset));
435 b = XFS_RMAP_OFF(be64_to_cpu(r2->rmap.rm_offset));
436 if (a <= b)
437 return 1;
438 return 0;
439}
440#endif /* DEBUG */
441
442static const struct xfs_btree_ops xfs_rmapbt_ops = {
443 .rec_len = sizeof(struct xfs_rmap_rec),
444 .key_len = 2 * sizeof(struct xfs_rmap_key),
445
446 .dup_cursor = xfs_rmapbt_dup_cursor,
447 .set_root = xfs_rmapbt_set_root,
448 .alloc_block = xfs_rmapbt_alloc_block,
449 .free_block = xfs_rmapbt_free_block,
450 .get_minrecs = xfs_rmapbt_get_minrecs,
451 .get_maxrecs = xfs_rmapbt_get_maxrecs,
452 .init_key_from_rec = xfs_rmapbt_init_key_from_rec,
453 .init_high_key_from_rec = xfs_rmapbt_init_high_key_from_rec,
454 .init_rec_from_cur = xfs_rmapbt_init_rec_from_cur,
455 .init_ptr_from_cur = xfs_rmapbt_init_ptr_from_cur,
456 .key_diff = xfs_rmapbt_key_diff,
457 .buf_ops = &xfs_rmapbt_buf_ops,
458 .diff_two_keys = xfs_rmapbt_diff_two_keys,
459#if defined(DEBUG) || defined(XFS_WARN)
460 .keys_inorder = xfs_rmapbt_keys_inorder,
461 .recs_inorder = xfs_rmapbt_recs_inorder,
462#endif
463};
464
465/*
466 * Allocate a new allocation btree cursor.
467 */
468struct xfs_btree_cur *
469xfs_rmapbt_init_cursor(
470 struct xfs_mount *mp,
471 struct xfs_trans *tp,
472 struct xfs_buf *agbp,
473 xfs_agnumber_t agno)
474{
475 struct xfs_agf *agf = XFS_BUF_TO_AGF(agbp);
476 struct xfs_btree_cur *cur;
477
478 cur = kmem_zone_zalloc(xfs_btree_cur_zone, KM_NOFS);
479 cur->bc_tp = tp;
480 cur->bc_mp = mp;
481 /* Overlapping btree; 2 keys per pointer. */
482 cur->bc_btnum = XFS_BTNUM_RMAP;
483 cur->bc_flags = XFS_BTREE_CRC_BLOCKS | XFS_BTREE_OVERLAPPING;
484 cur->bc_blocklog = mp->m_sb.sb_blocklog;
485 cur->bc_ops = &xfs_rmapbt_ops;
486 cur->bc_nlevels = be32_to_cpu(agf->agf_levels[XFS_BTNUM_RMAP]);
487 cur->bc_statoff = XFS_STATS_CALC_INDEX(xs_rmap_2);
488
489 cur->bc_private.a.agbp = agbp;
490 cur->bc_private.a.agno = agno;
491
492 return cur;
493}
494
495/*
496 * Calculate number of records in an rmap btree block.
497 */
498int
499xfs_rmapbt_maxrecs(
500 struct xfs_mount *mp,
501 int blocklen,
502 int leaf)
503{
504 blocklen -= XFS_RMAP_BLOCK_LEN;
505
506 if (leaf)
507 return blocklen / sizeof(struct xfs_rmap_rec);
508 return blocklen /
509 (2 * sizeof(struct xfs_rmap_key) + sizeof(xfs_rmap_ptr_t));
510}
511
512/* Compute the maximum height of an rmap btree. */
513void
514xfs_rmapbt_compute_maxlevels(
515 struct xfs_mount *mp)
516{
517 /*
518 * On a non-reflink filesystem, the maximum number of rmap
519 * records is the number of blocks in the AG, hence the max
520 * rmapbt height is log_$maxrecs($agblocks). However, with
521 * reflink each AG block can have up to 2^32 (per the refcount
522 * record format) owners, which means that theoretically we
523 * could face up to 2^64 rmap records.
524 *
525 * That effectively means that the max rmapbt height must be
526 * XFS_BTREE_MAXLEVELS. "Fortunately" we'll run out of AG
527 * blocks to feed the rmapbt long before the rmapbt reaches
528 * maximum height. The reflink code uses ag_resv_critical to
529 * disallow reflinking when less than 10% of the per-AG metadata
530 * block reservation since the fallback is a regular file copy.
531 */
532 if (xfs_sb_version_hasreflink(&mp->m_sb))
533 mp->m_rmap_maxlevels = XFS_BTREE_MAXLEVELS;
534 else
535 mp->m_rmap_maxlevels = xfs_btree_compute_maxlevels(mp,
536 mp->m_rmap_mnr, mp->m_sb.sb_agblocks);
537}
538
539/* Calculate the refcount btree size for some records. */
540xfs_extlen_t
541xfs_rmapbt_calc_size(
542 struct xfs_mount *mp,
543 unsigned long long len)
544{
545 return xfs_btree_calc_size(mp, mp->m_rmap_mnr, len);
546}
547
548/*
549 * Calculate the maximum refcount btree size.
550 */
551xfs_extlen_t
552xfs_rmapbt_max_size(
553 struct xfs_mount *mp,
554 xfs_agblock_t agblocks)
555{
556 /* Bail out if we're uninitialized, which can happen in mkfs. */
557 if (mp->m_rmap_mxr[0] == 0)
558 return 0;
559
560 return xfs_rmapbt_calc_size(mp, agblocks);
561}
562
563/*
564 * Figure out how many blocks to reserve and how many are used by this btree.
565 */
566int
567xfs_rmapbt_calc_reserves(
568 struct xfs_mount *mp,
569 xfs_agnumber_t agno,
570 xfs_extlen_t *ask,
571 xfs_extlen_t *used)
572{
573 struct xfs_buf *agbp;
574 struct xfs_agf *agf;
575 xfs_agblock_t agblocks;
576 xfs_extlen_t tree_len;
577 int error;
578
579 if (!xfs_sb_version_hasrmapbt(&mp->m_sb))
580 return 0;
581
582 error = xfs_alloc_read_agf(mp, NULL, agno, 0, &agbp);
583 if (error)
584 return error;
585
586 agf = XFS_BUF_TO_AGF(agbp);
587 agblocks = be32_to_cpu(agf->agf_length);
588 tree_len = be32_to_cpu(agf->agf_rmap_blocks);
589 xfs_buf_relse(agbp);
590
591 /* Reserve 1% of the AG or enough for 1 block per record. */
592 *ask += max(agblocks / 100, xfs_rmapbt_max_size(mp, agblocks));
593 *used += tree_len;
594
595 return error;
596}