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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright (c) 2000-2002,2005 Silicon Graphics, Inc.
4 * All Rights Reserved.
5 */
6#include "xfs.h"
7#include "xfs_fs.h"
8#include "xfs_format.h"
9#include "xfs_log_format.h"
10#include "xfs_shared.h"
11#include "xfs_trans_resv.h"
12#include "xfs_bit.h"
13#include "xfs_mount.h"
14#include "xfs_defer.h"
15#include "xfs_btree.h"
16#include "xfs_rmap.h"
17#include "xfs_alloc_btree.h"
18#include "xfs_alloc.h"
19#include "xfs_extent_busy.h"
20#include "xfs_errortag.h"
21#include "xfs_error.h"
22#include "xfs_trace.h"
23#include "xfs_trans.h"
24#include "xfs_buf_item.h"
25#include "xfs_log.h"
26#include "xfs_ag.h"
27#include "xfs_ag_resv.h"
28#include "xfs_bmap.h"
29#include "xfs_health.h"
30
31struct kmem_cache *xfs_extfree_item_cache;
32
33struct workqueue_struct *xfs_alloc_wq;
34
35#define XFS_ABSDIFF(a,b) (((a) <= (b)) ? ((b) - (a)) : ((a) - (b)))
36
37#define XFSA_FIXUP_BNO_OK 1
38#define XFSA_FIXUP_CNT_OK 2
39
40/*
41 * Size of the AGFL. For CRC-enabled filesystes we steal a couple of slots in
42 * the beginning of the block for a proper header with the location information
43 * and CRC.
44 */
45unsigned int
46xfs_agfl_size(
47 struct xfs_mount *mp)
48{
49 unsigned int size = mp->m_sb.sb_sectsize;
50
51 if (xfs_has_crc(mp))
52 size -= sizeof(struct xfs_agfl);
53
54 return size / sizeof(xfs_agblock_t);
55}
56
57unsigned int
58xfs_refc_block(
59 struct xfs_mount *mp)
60{
61 if (xfs_has_rmapbt(mp))
62 return XFS_RMAP_BLOCK(mp) + 1;
63 if (xfs_has_finobt(mp))
64 return XFS_FIBT_BLOCK(mp) + 1;
65 return XFS_IBT_BLOCK(mp) + 1;
66}
67
68xfs_extlen_t
69xfs_prealloc_blocks(
70 struct xfs_mount *mp)
71{
72 if (xfs_has_reflink(mp))
73 return xfs_refc_block(mp) + 1;
74 if (xfs_has_rmapbt(mp))
75 return XFS_RMAP_BLOCK(mp) + 1;
76 if (xfs_has_finobt(mp))
77 return XFS_FIBT_BLOCK(mp) + 1;
78 return XFS_IBT_BLOCK(mp) + 1;
79}
80
81/*
82 * The number of blocks per AG that we withhold from xfs_mod_fdblocks to
83 * guarantee that we can refill the AGFL prior to allocating space in a nearly
84 * full AG. Although the space described by the free space btrees, the
85 * blocks used by the freesp btrees themselves, and the blocks owned by the
86 * AGFL are counted in the ondisk fdblocks, it's a mistake to let the ondisk
87 * free space in the AG drop so low that the free space btrees cannot refill an
88 * empty AGFL up to the minimum level. Rather than grind through empty AGs
89 * until the fs goes down, we subtract this many AG blocks from the incore
90 * fdblocks to ensure user allocation does not overcommit the space the
91 * filesystem needs for the AGFLs. The rmap btree uses a per-AG reservation to
92 * withhold space from xfs_mod_fdblocks, so we do not account for that here.
93 */
94#define XFS_ALLOCBT_AGFL_RESERVE 4
95
96/*
97 * Compute the number of blocks that we set aside to guarantee the ability to
98 * refill the AGFL and handle a full bmap btree split.
99 *
100 * In order to avoid ENOSPC-related deadlock caused by out-of-order locking of
101 * AGF buffer (PV 947395), we place constraints on the relationship among
102 * actual allocations for data blocks, freelist blocks, and potential file data
103 * bmap btree blocks. However, these restrictions may result in no actual space
104 * allocated for a delayed extent, for example, a data block in a certain AG is
105 * allocated but there is no additional block for the additional bmap btree
106 * block due to a split of the bmap btree of the file. The result of this may
107 * lead to an infinite loop when the file gets flushed to disk and all delayed
108 * extents need to be actually allocated. To get around this, we explicitly set
109 * aside a few blocks which will not be reserved in delayed allocation.
110 *
111 * For each AG, we need to reserve enough blocks to replenish a totally empty
112 * AGFL and 4 more to handle a potential split of the file's bmap btree.
113 */
114unsigned int
115xfs_alloc_set_aside(
116 struct xfs_mount *mp)
117{
118 return mp->m_sb.sb_agcount * (XFS_ALLOCBT_AGFL_RESERVE + 4);
119}
120
121/*
122 * When deciding how much space to allocate out of an AG, we limit the
123 * allocation maximum size to the size the AG. However, we cannot use all the
124 * blocks in the AG - some are permanently used by metadata. These
125 * blocks are generally:
126 * - the AG superblock, AGF, AGI and AGFL
127 * - the AGF (bno and cnt) and AGI btree root blocks, and optionally
128 * the AGI free inode and rmap btree root blocks.
129 * - blocks on the AGFL according to xfs_alloc_set_aside() limits
130 * - the rmapbt root block
131 *
132 * The AG headers are sector sized, so the amount of space they take up is
133 * dependent on filesystem geometry. The others are all single blocks.
134 */
135unsigned int
136xfs_alloc_ag_max_usable(
137 struct xfs_mount *mp)
138{
139 unsigned int blocks;
140
141 blocks = XFS_BB_TO_FSB(mp, XFS_FSS_TO_BB(mp, 4)); /* ag headers */
142 blocks += XFS_ALLOCBT_AGFL_RESERVE;
143 blocks += 3; /* AGF, AGI btree root blocks */
144 if (xfs_has_finobt(mp))
145 blocks++; /* finobt root block */
146 if (xfs_has_rmapbt(mp))
147 blocks++; /* rmap root block */
148 if (xfs_has_reflink(mp))
149 blocks++; /* refcount root block */
150
151 return mp->m_sb.sb_agblocks - blocks;
152}
153
154
155static int
156xfs_alloc_lookup(
157 struct xfs_btree_cur *cur,
158 xfs_lookup_t dir,
159 xfs_agblock_t bno,
160 xfs_extlen_t len,
161 int *stat)
162{
163 int error;
164
165 cur->bc_rec.a.ar_startblock = bno;
166 cur->bc_rec.a.ar_blockcount = len;
167 error = xfs_btree_lookup(cur, dir, stat);
168 if (*stat == 1)
169 cur->bc_flags |= XFS_BTREE_ALLOCBT_ACTIVE;
170 else
171 cur->bc_flags &= ~XFS_BTREE_ALLOCBT_ACTIVE;
172 return error;
173}
174
175/*
176 * Lookup the record equal to [bno, len] in the btree given by cur.
177 */
178static inline int /* error */
179xfs_alloc_lookup_eq(
180 struct xfs_btree_cur *cur, /* btree cursor */
181 xfs_agblock_t bno, /* starting block of extent */
182 xfs_extlen_t len, /* length of extent */
183 int *stat) /* success/failure */
184{
185 return xfs_alloc_lookup(cur, XFS_LOOKUP_EQ, bno, len, stat);
186}
187
188/*
189 * Lookup the first record greater than or equal to [bno, len]
190 * in the btree given by cur.
191 */
192int /* error */
193xfs_alloc_lookup_ge(
194 struct xfs_btree_cur *cur, /* btree cursor */
195 xfs_agblock_t bno, /* starting block of extent */
196 xfs_extlen_t len, /* length of extent */
197 int *stat) /* success/failure */
198{
199 return xfs_alloc_lookup(cur, XFS_LOOKUP_GE, bno, len, stat);
200}
201
202/*
203 * Lookup the first record less than or equal to [bno, len]
204 * in the btree given by cur.
205 */
206int /* error */
207xfs_alloc_lookup_le(
208 struct xfs_btree_cur *cur, /* btree cursor */
209 xfs_agblock_t bno, /* starting block of extent */
210 xfs_extlen_t len, /* length of extent */
211 int *stat) /* success/failure */
212{
213 return xfs_alloc_lookup(cur, XFS_LOOKUP_LE, bno, len, stat);
214}
215
216static inline bool
217xfs_alloc_cur_active(
218 struct xfs_btree_cur *cur)
219{
220 return cur && (cur->bc_flags & XFS_BTREE_ALLOCBT_ACTIVE);
221}
222
223/*
224 * Update the record referred to by cur to the value given
225 * by [bno, len].
226 * This either works (return 0) or gets an EFSCORRUPTED error.
227 */
228STATIC int /* error */
229xfs_alloc_update(
230 struct xfs_btree_cur *cur, /* btree cursor */
231 xfs_agblock_t bno, /* starting block of extent */
232 xfs_extlen_t len) /* length of extent */
233{
234 union xfs_btree_rec rec;
235
236 rec.alloc.ar_startblock = cpu_to_be32(bno);
237 rec.alloc.ar_blockcount = cpu_to_be32(len);
238 return xfs_btree_update(cur, &rec);
239}
240
241/* Convert the ondisk btree record to its incore representation. */
242void
243xfs_alloc_btrec_to_irec(
244 const union xfs_btree_rec *rec,
245 struct xfs_alloc_rec_incore *irec)
246{
247 irec->ar_startblock = be32_to_cpu(rec->alloc.ar_startblock);
248 irec->ar_blockcount = be32_to_cpu(rec->alloc.ar_blockcount);
249}
250
251/* Simple checks for free space records. */
252xfs_failaddr_t
253xfs_alloc_check_irec(
254 struct xfs_perag *pag,
255 const struct xfs_alloc_rec_incore *irec)
256{
257 if (irec->ar_blockcount == 0)
258 return __this_address;
259
260 /* check for valid extent range, including overflow */
261 if (!xfs_verify_agbext(pag, irec->ar_startblock, irec->ar_blockcount))
262 return __this_address;
263
264 return NULL;
265}
266
267static inline int
268xfs_alloc_complain_bad_rec(
269 struct xfs_btree_cur *cur,
270 xfs_failaddr_t fa,
271 const struct xfs_alloc_rec_incore *irec)
272{
273 struct xfs_mount *mp = cur->bc_mp;
274
275 xfs_warn(mp,
276 "%sbt record corruption in AG %d detected at %pS!",
277 cur->bc_ops->name, cur->bc_ag.pag->pag_agno, fa);
278 xfs_warn(mp,
279 "start block 0x%x block count 0x%x", irec->ar_startblock,
280 irec->ar_blockcount);
281 xfs_btree_mark_sick(cur);
282 return -EFSCORRUPTED;
283}
284
285/*
286 * Get the data from the pointed-to record.
287 */
288int /* error */
289xfs_alloc_get_rec(
290 struct xfs_btree_cur *cur, /* btree cursor */
291 xfs_agblock_t *bno, /* output: starting block of extent */
292 xfs_extlen_t *len, /* output: length of extent */
293 int *stat) /* output: success/failure */
294{
295 struct xfs_alloc_rec_incore irec;
296 union xfs_btree_rec *rec;
297 xfs_failaddr_t fa;
298 int error;
299
300 error = xfs_btree_get_rec(cur, &rec, stat);
301 if (error || !(*stat))
302 return error;
303
304 xfs_alloc_btrec_to_irec(rec, &irec);
305 fa = xfs_alloc_check_irec(cur->bc_ag.pag, &irec);
306 if (fa)
307 return xfs_alloc_complain_bad_rec(cur, fa, &irec);
308
309 *bno = irec.ar_startblock;
310 *len = irec.ar_blockcount;
311 return 0;
312}
313
314/*
315 * Compute aligned version of the found extent.
316 * Takes alignment and min length into account.
317 */
318STATIC bool
319xfs_alloc_compute_aligned(
320 xfs_alloc_arg_t *args, /* allocation argument structure */
321 xfs_agblock_t foundbno, /* starting block in found extent */
322 xfs_extlen_t foundlen, /* length in found extent */
323 xfs_agblock_t *resbno, /* result block number */
324 xfs_extlen_t *reslen, /* result length */
325 unsigned *busy_gen)
326{
327 xfs_agblock_t bno = foundbno;
328 xfs_extlen_t len = foundlen;
329 xfs_extlen_t diff;
330 bool busy;
331
332 /* Trim busy sections out of found extent */
333 busy = xfs_extent_busy_trim(args, &bno, &len, busy_gen);
334
335 /*
336 * If we have a largish extent that happens to start before min_agbno,
337 * see if we can shift it into range...
338 */
339 if (bno < args->min_agbno && bno + len > args->min_agbno) {
340 diff = args->min_agbno - bno;
341 if (len > diff) {
342 bno += diff;
343 len -= diff;
344 }
345 }
346
347 if (args->alignment > 1 && len >= args->minlen) {
348 xfs_agblock_t aligned_bno = roundup(bno, args->alignment);
349
350 diff = aligned_bno - bno;
351
352 *resbno = aligned_bno;
353 *reslen = diff >= len ? 0 : len - diff;
354 } else {
355 *resbno = bno;
356 *reslen = len;
357 }
358
359 return busy;
360}
361
362/*
363 * Compute best start block and diff for "near" allocations.
364 * freelen >= wantlen already checked by caller.
365 */
366STATIC xfs_extlen_t /* difference value (absolute) */
367xfs_alloc_compute_diff(
368 xfs_agblock_t wantbno, /* target starting block */
369 xfs_extlen_t wantlen, /* target length */
370 xfs_extlen_t alignment, /* target alignment */
371 int datatype, /* are we allocating data? */
372 xfs_agblock_t freebno, /* freespace's starting block */
373 xfs_extlen_t freelen, /* freespace's length */
374 xfs_agblock_t *newbnop) /* result: best start block from free */
375{
376 xfs_agblock_t freeend; /* end of freespace extent */
377 xfs_agblock_t newbno1; /* return block number */
378 xfs_agblock_t newbno2; /* other new block number */
379 xfs_extlen_t newlen1=0; /* length with newbno1 */
380 xfs_extlen_t newlen2=0; /* length with newbno2 */
381 xfs_agblock_t wantend; /* end of target extent */
382 bool userdata = datatype & XFS_ALLOC_USERDATA;
383
384 ASSERT(freelen >= wantlen);
385 freeend = freebno + freelen;
386 wantend = wantbno + wantlen;
387 /*
388 * We want to allocate from the start of a free extent if it is past
389 * the desired block or if we are allocating user data and the free
390 * extent is before desired block. The second case is there to allow
391 * for contiguous allocation from the remaining free space if the file
392 * grows in the short term.
393 */
394 if (freebno >= wantbno || (userdata && freeend < wantend)) {
395 if ((newbno1 = roundup(freebno, alignment)) >= freeend)
396 newbno1 = NULLAGBLOCK;
397 } else if (freeend >= wantend && alignment > 1) {
398 newbno1 = roundup(wantbno, alignment);
399 newbno2 = newbno1 - alignment;
400 if (newbno1 >= freeend)
401 newbno1 = NULLAGBLOCK;
402 else
403 newlen1 = XFS_EXTLEN_MIN(wantlen, freeend - newbno1);
404 if (newbno2 < freebno)
405 newbno2 = NULLAGBLOCK;
406 else
407 newlen2 = XFS_EXTLEN_MIN(wantlen, freeend - newbno2);
408 if (newbno1 != NULLAGBLOCK && newbno2 != NULLAGBLOCK) {
409 if (newlen1 < newlen2 ||
410 (newlen1 == newlen2 &&
411 XFS_ABSDIFF(newbno1, wantbno) >
412 XFS_ABSDIFF(newbno2, wantbno)))
413 newbno1 = newbno2;
414 } else if (newbno2 != NULLAGBLOCK)
415 newbno1 = newbno2;
416 } else if (freeend >= wantend) {
417 newbno1 = wantbno;
418 } else if (alignment > 1) {
419 newbno1 = roundup(freeend - wantlen, alignment);
420 if (newbno1 > freeend - wantlen &&
421 newbno1 - alignment >= freebno)
422 newbno1 -= alignment;
423 else if (newbno1 >= freeend)
424 newbno1 = NULLAGBLOCK;
425 } else
426 newbno1 = freeend - wantlen;
427 *newbnop = newbno1;
428 return newbno1 == NULLAGBLOCK ? 0 : XFS_ABSDIFF(newbno1, wantbno);
429}
430
431/*
432 * Fix up the length, based on mod and prod.
433 * len should be k * prod + mod for some k.
434 * If len is too small it is returned unchanged.
435 * If len hits maxlen it is left alone.
436 */
437STATIC void
438xfs_alloc_fix_len(
439 xfs_alloc_arg_t *args) /* allocation argument structure */
440{
441 xfs_extlen_t k;
442 xfs_extlen_t rlen;
443
444 ASSERT(args->mod < args->prod);
445 rlen = args->len;
446 ASSERT(rlen >= args->minlen);
447 ASSERT(rlen <= args->maxlen);
448 if (args->prod <= 1 || rlen < args->mod || rlen == args->maxlen ||
449 (args->mod == 0 && rlen < args->prod))
450 return;
451 k = rlen % args->prod;
452 if (k == args->mod)
453 return;
454 if (k > args->mod)
455 rlen = rlen - (k - args->mod);
456 else
457 rlen = rlen - args->prod + (args->mod - k);
458 /* casts to (int) catch length underflows */
459 if ((int)rlen < (int)args->minlen)
460 return;
461 ASSERT(rlen >= args->minlen && rlen <= args->maxlen);
462 ASSERT(rlen % args->prod == args->mod);
463 ASSERT(args->pag->pagf_freeblks + args->pag->pagf_flcount >=
464 rlen + args->minleft);
465 args->len = rlen;
466}
467
468/*
469 * Update the two btrees, logically removing from freespace the extent
470 * starting at rbno, rlen blocks. The extent is contained within the
471 * actual (current) free extent fbno for flen blocks.
472 * Flags are passed in indicating whether the cursors are set to the
473 * relevant records.
474 */
475STATIC int /* error code */
476xfs_alloc_fixup_trees(
477 struct xfs_btree_cur *cnt_cur, /* cursor for by-size btree */
478 struct xfs_btree_cur *bno_cur, /* cursor for by-block btree */
479 xfs_agblock_t fbno, /* starting block of free extent */
480 xfs_extlen_t flen, /* length of free extent */
481 xfs_agblock_t rbno, /* starting block of returned extent */
482 xfs_extlen_t rlen, /* length of returned extent */
483 int flags) /* flags, XFSA_FIXUP_... */
484{
485 int error; /* error code */
486 int i; /* operation results */
487 xfs_agblock_t nfbno1; /* first new free startblock */
488 xfs_agblock_t nfbno2; /* second new free startblock */
489 xfs_extlen_t nflen1=0; /* first new free length */
490 xfs_extlen_t nflen2=0; /* second new free length */
491 struct xfs_mount *mp;
492
493 mp = cnt_cur->bc_mp;
494
495 /*
496 * Look up the record in the by-size tree if necessary.
497 */
498 if (flags & XFSA_FIXUP_CNT_OK) {
499#ifdef DEBUG
500 if ((error = xfs_alloc_get_rec(cnt_cur, &nfbno1, &nflen1, &i)))
501 return error;
502 if (XFS_IS_CORRUPT(mp,
503 i != 1 ||
504 nfbno1 != fbno ||
505 nflen1 != flen)) {
506 xfs_btree_mark_sick(cnt_cur);
507 return -EFSCORRUPTED;
508 }
509#endif
510 } else {
511 if ((error = xfs_alloc_lookup_eq(cnt_cur, fbno, flen, &i)))
512 return error;
513 if (XFS_IS_CORRUPT(mp, i != 1)) {
514 xfs_btree_mark_sick(cnt_cur);
515 return -EFSCORRUPTED;
516 }
517 }
518 /*
519 * Look up the record in the by-block tree if necessary.
520 */
521 if (flags & XFSA_FIXUP_BNO_OK) {
522#ifdef DEBUG
523 if ((error = xfs_alloc_get_rec(bno_cur, &nfbno1, &nflen1, &i)))
524 return error;
525 if (XFS_IS_CORRUPT(mp,
526 i != 1 ||
527 nfbno1 != fbno ||
528 nflen1 != flen)) {
529 xfs_btree_mark_sick(bno_cur);
530 return -EFSCORRUPTED;
531 }
532#endif
533 } else {
534 if ((error = xfs_alloc_lookup_eq(bno_cur, fbno, flen, &i)))
535 return error;
536 if (XFS_IS_CORRUPT(mp, i != 1)) {
537 xfs_btree_mark_sick(bno_cur);
538 return -EFSCORRUPTED;
539 }
540 }
541
542#ifdef DEBUG
543 if (bno_cur->bc_nlevels == 1 && cnt_cur->bc_nlevels == 1) {
544 struct xfs_btree_block *bnoblock;
545 struct xfs_btree_block *cntblock;
546
547 bnoblock = XFS_BUF_TO_BLOCK(bno_cur->bc_levels[0].bp);
548 cntblock = XFS_BUF_TO_BLOCK(cnt_cur->bc_levels[0].bp);
549
550 if (XFS_IS_CORRUPT(mp,
551 bnoblock->bb_numrecs !=
552 cntblock->bb_numrecs)) {
553 xfs_btree_mark_sick(bno_cur);
554 return -EFSCORRUPTED;
555 }
556 }
557#endif
558
559 /*
560 * Deal with all four cases: the allocated record is contained
561 * within the freespace record, so we can have new freespace
562 * at either (or both) end, or no freespace remaining.
563 */
564 if (rbno == fbno && rlen == flen)
565 nfbno1 = nfbno2 = NULLAGBLOCK;
566 else if (rbno == fbno) {
567 nfbno1 = rbno + rlen;
568 nflen1 = flen - rlen;
569 nfbno2 = NULLAGBLOCK;
570 } else if (rbno + rlen == fbno + flen) {
571 nfbno1 = fbno;
572 nflen1 = flen - rlen;
573 nfbno2 = NULLAGBLOCK;
574 } else {
575 nfbno1 = fbno;
576 nflen1 = rbno - fbno;
577 nfbno2 = rbno + rlen;
578 nflen2 = (fbno + flen) - nfbno2;
579 }
580 /*
581 * Delete the entry from the by-size btree.
582 */
583 if ((error = xfs_btree_delete(cnt_cur, &i)))
584 return error;
585 if (XFS_IS_CORRUPT(mp, i != 1)) {
586 xfs_btree_mark_sick(cnt_cur);
587 return -EFSCORRUPTED;
588 }
589 /*
590 * Add new by-size btree entry(s).
591 */
592 if (nfbno1 != NULLAGBLOCK) {
593 if ((error = xfs_alloc_lookup_eq(cnt_cur, nfbno1, nflen1, &i)))
594 return error;
595 if (XFS_IS_CORRUPT(mp, i != 0)) {
596 xfs_btree_mark_sick(cnt_cur);
597 return -EFSCORRUPTED;
598 }
599 if ((error = xfs_btree_insert(cnt_cur, &i)))
600 return error;
601 if (XFS_IS_CORRUPT(mp, i != 1)) {
602 xfs_btree_mark_sick(cnt_cur);
603 return -EFSCORRUPTED;
604 }
605 }
606 if (nfbno2 != NULLAGBLOCK) {
607 if ((error = xfs_alloc_lookup_eq(cnt_cur, nfbno2, nflen2, &i)))
608 return error;
609 if (XFS_IS_CORRUPT(mp, i != 0)) {
610 xfs_btree_mark_sick(cnt_cur);
611 return -EFSCORRUPTED;
612 }
613 if ((error = xfs_btree_insert(cnt_cur, &i)))
614 return error;
615 if (XFS_IS_CORRUPT(mp, i != 1)) {
616 xfs_btree_mark_sick(cnt_cur);
617 return -EFSCORRUPTED;
618 }
619 }
620 /*
621 * Fix up the by-block btree entry(s).
622 */
623 if (nfbno1 == NULLAGBLOCK) {
624 /*
625 * No remaining freespace, just delete the by-block tree entry.
626 */
627 if ((error = xfs_btree_delete(bno_cur, &i)))
628 return error;
629 if (XFS_IS_CORRUPT(mp, i != 1)) {
630 xfs_btree_mark_sick(bno_cur);
631 return -EFSCORRUPTED;
632 }
633 } else {
634 /*
635 * Update the by-block entry to start later|be shorter.
636 */
637 if ((error = xfs_alloc_update(bno_cur, nfbno1, nflen1)))
638 return error;
639 }
640 if (nfbno2 != NULLAGBLOCK) {
641 /*
642 * 2 resulting free entries, need to add one.
643 */
644 if ((error = xfs_alloc_lookup_eq(bno_cur, nfbno2, nflen2, &i)))
645 return error;
646 if (XFS_IS_CORRUPT(mp, i != 0)) {
647 xfs_btree_mark_sick(bno_cur);
648 return -EFSCORRUPTED;
649 }
650 if ((error = xfs_btree_insert(bno_cur, &i)))
651 return error;
652 if (XFS_IS_CORRUPT(mp, i != 1)) {
653 xfs_btree_mark_sick(bno_cur);
654 return -EFSCORRUPTED;
655 }
656 }
657 return 0;
658}
659
660/*
661 * We do not verify the AGFL contents against AGF-based index counters here,
662 * even though we may have access to the perag that contains shadow copies. We
663 * don't know if the AGF based counters have been checked, and if they have they
664 * still may be inconsistent because they haven't yet been reset on the first
665 * allocation after the AGF has been read in.
666 *
667 * This means we can only check that all agfl entries contain valid or null
668 * values because we can't reliably determine the active range to exclude
669 * NULLAGBNO as a valid value.
670 *
671 * However, we can't even do that for v4 format filesystems because there are
672 * old versions of mkfs out there that does not initialise the AGFL to known,
673 * verifiable values. HEnce we can't tell the difference between a AGFL block
674 * allocated by mkfs and a corrupted AGFL block here on v4 filesystems.
675 *
676 * As a result, we can only fully validate AGFL block numbers when we pull them
677 * from the freelist in xfs_alloc_get_freelist().
678 */
679static xfs_failaddr_t
680xfs_agfl_verify(
681 struct xfs_buf *bp)
682{
683 struct xfs_mount *mp = bp->b_mount;
684 struct xfs_agfl *agfl = XFS_BUF_TO_AGFL(bp);
685 __be32 *agfl_bno = xfs_buf_to_agfl_bno(bp);
686 int i;
687
688 if (!xfs_has_crc(mp))
689 return NULL;
690
691 if (!xfs_verify_magic(bp, agfl->agfl_magicnum))
692 return __this_address;
693 if (!uuid_equal(&agfl->agfl_uuid, &mp->m_sb.sb_meta_uuid))
694 return __this_address;
695 /*
696 * during growfs operations, the perag is not fully initialised,
697 * so we can't use it for any useful checking. growfs ensures we can't
698 * use it by using uncached buffers that don't have the perag attached
699 * so we can detect and avoid this problem.
700 */
701 if (bp->b_pag && be32_to_cpu(agfl->agfl_seqno) != bp->b_pag->pag_agno)
702 return __this_address;
703
704 for (i = 0; i < xfs_agfl_size(mp); i++) {
705 if (be32_to_cpu(agfl_bno[i]) != NULLAGBLOCK &&
706 be32_to_cpu(agfl_bno[i]) >= mp->m_sb.sb_agblocks)
707 return __this_address;
708 }
709
710 if (!xfs_log_check_lsn(mp, be64_to_cpu(XFS_BUF_TO_AGFL(bp)->agfl_lsn)))
711 return __this_address;
712 return NULL;
713}
714
715static void
716xfs_agfl_read_verify(
717 struct xfs_buf *bp)
718{
719 struct xfs_mount *mp = bp->b_mount;
720 xfs_failaddr_t fa;
721
722 /*
723 * There is no verification of non-crc AGFLs because mkfs does not
724 * initialise the AGFL to zero or NULL. Hence the only valid part of the
725 * AGFL is what the AGF says is active. We can't get to the AGF, so we
726 * can't verify just those entries are valid.
727 */
728 if (!xfs_has_crc(mp))
729 return;
730
731 if (!xfs_buf_verify_cksum(bp, XFS_AGFL_CRC_OFF))
732 xfs_verifier_error(bp, -EFSBADCRC, __this_address);
733 else {
734 fa = xfs_agfl_verify(bp);
735 if (fa)
736 xfs_verifier_error(bp, -EFSCORRUPTED, fa);
737 }
738}
739
740static void
741xfs_agfl_write_verify(
742 struct xfs_buf *bp)
743{
744 struct xfs_mount *mp = bp->b_mount;
745 struct xfs_buf_log_item *bip = bp->b_log_item;
746 xfs_failaddr_t fa;
747
748 /* no verification of non-crc AGFLs */
749 if (!xfs_has_crc(mp))
750 return;
751
752 fa = xfs_agfl_verify(bp);
753 if (fa) {
754 xfs_verifier_error(bp, -EFSCORRUPTED, fa);
755 return;
756 }
757
758 if (bip)
759 XFS_BUF_TO_AGFL(bp)->agfl_lsn = cpu_to_be64(bip->bli_item.li_lsn);
760
761 xfs_buf_update_cksum(bp, XFS_AGFL_CRC_OFF);
762}
763
764const struct xfs_buf_ops xfs_agfl_buf_ops = {
765 .name = "xfs_agfl",
766 .magic = { cpu_to_be32(XFS_AGFL_MAGIC), cpu_to_be32(XFS_AGFL_MAGIC) },
767 .verify_read = xfs_agfl_read_verify,
768 .verify_write = xfs_agfl_write_verify,
769 .verify_struct = xfs_agfl_verify,
770};
771
772/*
773 * Read in the allocation group free block array.
774 */
775int
776xfs_alloc_read_agfl(
777 struct xfs_perag *pag,
778 struct xfs_trans *tp,
779 struct xfs_buf **bpp)
780{
781 struct xfs_mount *mp = pag->pag_mount;
782 struct xfs_buf *bp;
783 int error;
784
785 error = xfs_trans_read_buf(
786 mp, tp, mp->m_ddev_targp,
787 XFS_AG_DADDR(mp, pag->pag_agno, XFS_AGFL_DADDR(mp)),
788 XFS_FSS_TO_BB(mp, 1), 0, &bp, &xfs_agfl_buf_ops);
789 if (xfs_metadata_is_sick(error))
790 xfs_ag_mark_sick(pag, XFS_SICK_AG_AGFL);
791 if (error)
792 return error;
793 xfs_buf_set_ref(bp, XFS_AGFL_REF);
794 *bpp = bp;
795 return 0;
796}
797
798STATIC int
799xfs_alloc_update_counters(
800 struct xfs_trans *tp,
801 struct xfs_buf *agbp,
802 long len)
803{
804 struct xfs_agf *agf = agbp->b_addr;
805
806 agbp->b_pag->pagf_freeblks += len;
807 be32_add_cpu(&agf->agf_freeblks, len);
808
809 if (unlikely(be32_to_cpu(agf->agf_freeblks) >
810 be32_to_cpu(agf->agf_length))) {
811 xfs_buf_mark_corrupt(agbp);
812 xfs_ag_mark_sick(agbp->b_pag, XFS_SICK_AG_AGF);
813 return -EFSCORRUPTED;
814 }
815
816 xfs_alloc_log_agf(tp, agbp, XFS_AGF_FREEBLKS);
817 return 0;
818}
819
820/*
821 * Block allocation algorithm and data structures.
822 */
823struct xfs_alloc_cur {
824 struct xfs_btree_cur *cnt; /* btree cursors */
825 struct xfs_btree_cur *bnolt;
826 struct xfs_btree_cur *bnogt;
827 xfs_extlen_t cur_len;/* current search length */
828 xfs_agblock_t rec_bno;/* extent startblock */
829 xfs_extlen_t rec_len;/* extent length */
830 xfs_agblock_t bno; /* alloc bno */
831 xfs_extlen_t len; /* alloc len */
832 xfs_extlen_t diff; /* diff from search bno */
833 unsigned int busy_gen;/* busy state */
834 bool busy;
835};
836
837/*
838 * Set up cursors, etc. in the extent allocation cursor. This function can be
839 * called multiple times to reset an initialized structure without having to
840 * reallocate cursors.
841 */
842static int
843xfs_alloc_cur_setup(
844 struct xfs_alloc_arg *args,
845 struct xfs_alloc_cur *acur)
846{
847 int error;
848 int i;
849
850 acur->cur_len = args->maxlen;
851 acur->rec_bno = 0;
852 acur->rec_len = 0;
853 acur->bno = 0;
854 acur->len = 0;
855 acur->diff = -1;
856 acur->busy = false;
857 acur->busy_gen = 0;
858
859 /*
860 * Perform an initial cntbt lookup to check for availability of maxlen
861 * extents. If this fails, we'll return -ENOSPC to signal the caller to
862 * attempt a small allocation.
863 */
864 if (!acur->cnt)
865 acur->cnt = xfs_cntbt_init_cursor(args->mp, args->tp,
866 args->agbp, args->pag);
867 error = xfs_alloc_lookup_ge(acur->cnt, 0, args->maxlen, &i);
868 if (error)
869 return error;
870
871 /*
872 * Allocate the bnobt left and right search cursors.
873 */
874 if (!acur->bnolt)
875 acur->bnolt = xfs_bnobt_init_cursor(args->mp, args->tp,
876 args->agbp, args->pag);
877 if (!acur->bnogt)
878 acur->bnogt = xfs_bnobt_init_cursor(args->mp, args->tp,
879 args->agbp, args->pag);
880 return i == 1 ? 0 : -ENOSPC;
881}
882
883static void
884xfs_alloc_cur_close(
885 struct xfs_alloc_cur *acur,
886 bool error)
887{
888 int cur_error = XFS_BTREE_NOERROR;
889
890 if (error)
891 cur_error = XFS_BTREE_ERROR;
892
893 if (acur->cnt)
894 xfs_btree_del_cursor(acur->cnt, cur_error);
895 if (acur->bnolt)
896 xfs_btree_del_cursor(acur->bnolt, cur_error);
897 if (acur->bnogt)
898 xfs_btree_del_cursor(acur->bnogt, cur_error);
899 acur->cnt = acur->bnolt = acur->bnogt = NULL;
900}
901
902/*
903 * Check an extent for allocation and track the best available candidate in the
904 * allocation structure. The cursor is deactivated if it has entered an out of
905 * range state based on allocation arguments. Optionally return the extent
906 * extent geometry and allocation status if requested by the caller.
907 */
908static int
909xfs_alloc_cur_check(
910 struct xfs_alloc_arg *args,
911 struct xfs_alloc_cur *acur,
912 struct xfs_btree_cur *cur,
913 int *new)
914{
915 int error, i;
916 xfs_agblock_t bno, bnoa, bnew;
917 xfs_extlen_t len, lena, diff = -1;
918 bool busy;
919 unsigned busy_gen = 0;
920 bool deactivate = false;
921 bool isbnobt = xfs_btree_is_bno(cur->bc_ops);
922
923 *new = 0;
924
925 error = xfs_alloc_get_rec(cur, &bno, &len, &i);
926 if (error)
927 return error;
928 if (XFS_IS_CORRUPT(args->mp, i != 1)) {
929 xfs_btree_mark_sick(cur);
930 return -EFSCORRUPTED;
931 }
932
933 /*
934 * Check minlen and deactivate a cntbt cursor if out of acceptable size
935 * range (i.e., walking backwards looking for a minlen extent).
936 */
937 if (len < args->minlen) {
938 deactivate = !isbnobt;
939 goto out;
940 }
941
942 busy = xfs_alloc_compute_aligned(args, bno, len, &bnoa, &lena,
943 &busy_gen);
944 acur->busy |= busy;
945 if (busy)
946 acur->busy_gen = busy_gen;
947 /* deactivate a bnobt cursor outside of locality range */
948 if (bnoa < args->min_agbno || bnoa > args->max_agbno) {
949 deactivate = isbnobt;
950 goto out;
951 }
952 if (lena < args->minlen)
953 goto out;
954
955 args->len = XFS_EXTLEN_MIN(lena, args->maxlen);
956 xfs_alloc_fix_len(args);
957 ASSERT(args->len >= args->minlen);
958 if (args->len < acur->len)
959 goto out;
960
961 /*
962 * We have an aligned record that satisfies minlen and beats or matches
963 * the candidate extent size. Compare locality for near allocation mode.
964 */
965 diff = xfs_alloc_compute_diff(args->agbno, args->len,
966 args->alignment, args->datatype,
967 bnoa, lena, &bnew);
968 if (bnew == NULLAGBLOCK)
969 goto out;
970
971 /*
972 * Deactivate a bnobt cursor with worse locality than the current best.
973 */
974 if (diff > acur->diff) {
975 deactivate = isbnobt;
976 goto out;
977 }
978
979 ASSERT(args->len > acur->len ||
980 (args->len == acur->len && diff <= acur->diff));
981 acur->rec_bno = bno;
982 acur->rec_len = len;
983 acur->bno = bnew;
984 acur->len = args->len;
985 acur->diff = diff;
986 *new = 1;
987
988 /*
989 * We're done if we found a perfect allocation. This only deactivates
990 * the current cursor, but this is just an optimization to terminate a
991 * cntbt search that otherwise runs to the edge of the tree.
992 */
993 if (acur->diff == 0 && acur->len == args->maxlen)
994 deactivate = true;
995out:
996 if (deactivate)
997 cur->bc_flags &= ~XFS_BTREE_ALLOCBT_ACTIVE;
998 trace_xfs_alloc_cur_check(cur, bno, len, diff, *new);
999 return 0;
1000}
1001
1002/*
1003 * Complete an allocation of a candidate extent. Remove the extent from both
1004 * trees and update the args structure.
1005 */
1006STATIC int
1007xfs_alloc_cur_finish(
1008 struct xfs_alloc_arg *args,
1009 struct xfs_alloc_cur *acur)
1010{
1011 struct xfs_agf __maybe_unused *agf = args->agbp->b_addr;
1012 int error;
1013
1014 ASSERT(acur->cnt && acur->bnolt);
1015 ASSERT(acur->bno >= acur->rec_bno);
1016 ASSERT(acur->bno + acur->len <= acur->rec_bno + acur->rec_len);
1017 ASSERT(acur->rec_bno + acur->rec_len <= be32_to_cpu(agf->agf_length));
1018
1019 error = xfs_alloc_fixup_trees(acur->cnt, acur->bnolt, acur->rec_bno,
1020 acur->rec_len, acur->bno, acur->len, 0);
1021 if (error)
1022 return error;
1023
1024 args->agbno = acur->bno;
1025 args->len = acur->len;
1026 args->wasfromfl = 0;
1027
1028 trace_xfs_alloc_cur(args);
1029 return 0;
1030}
1031
1032/*
1033 * Locality allocation lookup algorithm. This expects a cntbt cursor and uses
1034 * bno optimized lookup to search for extents with ideal size and locality.
1035 */
1036STATIC int
1037xfs_alloc_cntbt_iter(
1038 struct xfs_alloc_arg *args,
1039 struct xfs_alloc_cur *acur)
1040{
1041 struct xfs_btree_cur *cur = acur->cnt;
1042 xfs_agblock_t bno;
1043 xfs_extlen_t len, cur_len;
1044 int error;
1045 int i;
1046
1047 if (!xfs_alloc_cur_active(cur))
1048 return 0;
1049
1050 /* locality optimized lookup */
1051 cur_len = acur->cur_len;
1052 error = xfs_alloc_lookup_ge(cur, args->agbno, cur_len, &i);
1053 if (error)
1054 return error;
1055 if (i == 0)
1056 return 0;
1057 error = xfs_alloc_get_rec(cur, &bno, &len, &i);
1058 if (error)
1059 return error;
1060
1061 /* check the current record and update search length from it */
1062 error = xfs_alloc_cur_check(args, acur, cur, &i);
1063 if (error)
1064 return error;
1065 ASSERT(len >= acur->cur_len);
1066 acur->cur_len = len;
1067
1068 /*
1069 * We looked up the first record >= [agbno, len] above. The agbno is a
1070 * secondary key and so the current record may lie just before or after
1071 * agbno. If it is past agbno, check the previous record too so long as
1072 * the length matches as it may be closer. Don't check a smaller record
1073 * because that could deactivate our cursor.
1074 */
1075 if (bno > args->agbno) {
1076 error = xfs_btree_decrement(cur, 0, &i);
1077 if (!error && i) {
1078 error = xfs_alloc_get_rec(cur, &bno, &len, &i);
1079 if (!error && i && len == acur->cur_len)
1080 error = xfs_alloc_cur_check(args, acur, cur,
1081 &i);
1082 }
1083 if (error)
1084 return error;
1085 }
1086
1087 /*
1088 * Increment the search key until we find at least one allocation
1089 * candidate or if the extent we found was larger. Otherwise, double the
1090 * search key to optimize the search. Efficiency is more important here
1091 * than absolute best locality.
1092 */
1093 cur_len <<= 1;
1094 if (!acur->len || acur->cur_len >= cur_len)
1095 acur->cur_len++;
1096 else
1097 acur->cur_len = cur_len;
1098
1099 return error;
1100}
1101
1102/*
1103 * Deal with the case where only small freespaces remain. Either return the
1104 * contents of the last freespace record, or allocate space from the freelist if
1105 * there is nothing in the tree.
1106 */
1107STATIC int /* error */
1108xfs_alloc_ag_vextent_small(
1109 struct xfs_alloc_arg *args, /* allocation argument structure */
1110 struct xfs_btree_cur *ccur, /* optional by-size cursor */
1111 xfs_agblock_t *fbnop, /* result block number */
1112 xfs_extlen_t *flenp, /* result length */
1113 int *stat) /* status: 0-freelist, 1-normal/none */
1114{
1115 struct xfs_agf *agf = args->agbp->b_addr;
1116 int error = 0;
1117 xfs_agblock_t fbno = NULLAGBLOCK;
1118 xfs_extlen_t flen = 0;
1119 int i = 0;
1120
1121 /*
1122 * If a cntbt cursor is provided, try to allocate the largest record in
1123 * the tree. Try the AGFL if the cntbt is empty, otherwise fail the
1124 * allocation. Make sure to respect minleft even when pulling from the
1125 * freelist.
1126 */
1127 if (ccur)
1128 error = xfs_btree_decrement(ccur, 0, &i);
1129 if (error)
1130 goto error;
1131 if (i) {
1132 error = xfs_alloc_get_rec(ccur, &fbno, &flen, &i);
1133 if (error)
1134 goto error;
1135 if (XFS_IS_CORRUPT(args->mp, i != 1)) {
1136 xfs_btree_mark_sick(ccur);
1137 error = -EFSCORRUPTED;
1138 goto error;
1139 }
1140 goto out;
1141 }
1142
1143 if (args->minlen != 1 || args->alignment != 1 ||
1144 args->resv == XFS_AG_RESV_AGFL ||
1145 be32_to_cpu(agf->agf_flcount) <= args->minleft)
1146 goto out;
1147
1148 error = xfs_alloc_get_freelist(args->pag, args->tp, args->agbp,
1149 &fbno, 0);
1150 if (error)
1151 goto error;
1152 if (fbno == NULLAGBLOCK)
1153 goto out;
1154
1155 xfs_extent_busy_reuse(args->mp, args->pag, fbno, 1,
1156 (args->datatype & XFS_ALLOC_NOBUSY));
1157
1158 if (args->datatype & XFS_ALLOC_USERDATA) {
1159 struct xfs_buf *bp;
1160
1161 error = xfs_trans_get_buf(args->tp, args->mp->m_ddev_targp,
1162 XFS_AGB_TO_DADDR(args->mp, args->agno, fbno),
1163 args->mp->m_bsize, 0, &bp);
1164 if (error)
1165 goto error;
1166 xfs_trans_binval(args->tp, bp);
1167 }
1168 *fbnop = args->agbno = fbno;
1169 *flenp = args->len = 1;
1170 if (XFS_IS_CORRUPT(args->mp, fbno >= be32_to_cpu(agf->agf_length))) {
1171 xfs_btree_mark_sick(ccur);
1172 error = -EFSCORRUPTED;
1173 goto error;
1174 }
1175 args->wasfromfl = 1;
1176 trace_xfs_alloc_small_freelist(args);
1177
1178 /*
1179 * If we're feeding an AGFL block to something that doesn't live in the
1180 * free space, we need to clear out the OWN_AG rmap.
1181 */
1182 error = xfs_rmap_free(args->tp, args->agbp, args->pag, fbno, 1,
1183 &XFS_RMAP_OINFO_AG);
1184 if (error)
1185 goto error;
1186
1187 *stat = 0;
1188 return 0;
1189
1190out:
1191 /*
1192 * Can't do the allocation, give up.
1193 */
1194 if (flen < args->minlen) {
1195 args->agbno = NULLAGBLOCK;
1196 trace_xfs_alloc_small_notenough(args);
1197 flen = 0;
1198 }
1199 *fbnop = fbno;
1200 *flenp = flen;
1201 *stat = 1;
1202 trace_xfs_alloc_small_done(args);
1203 return 0;
1204
1205error:
1206 trace_xfs_alloc_small_error(args);
1207 return error;
1208}
1209
1210/*
1211 * Allocate a variable extent at exactly agno/bno.
1212 * Extent's length (returned in *len) will be between minlen and maxlen,
1213 * and of the form k * prod + mod unless there's nothing that large.
1214 * Return the starting a.g. block (bno), or NULLAGBLOCK if we can't do it.
1215 */
1216STATIC int /* error */
1217xfs_alloc_ag_vextent_exact(
1218 xfs_alloc_arg_t *args) /* allocation argument structure */
1219{
1220 struct xfs_agf __maybe_unused *agf = args->agbp->b_addr;
1221 struct xfs_btree_cur *bno_cur;/* by block-number btree cursor */
1222 struct xfs_btree_cur *cnt_cur;/* by count btree cursor */
1223 int error;
1224 xfs_agblock_t fbno; /* start block of found extent */
1225 xfs_extlen_t flen; /* length of found extent */
1226 xfs_agblock_t tbno; /* start block of busy extent */
1227 xfs_extlen_t tlen; /* length of busy extent */
1228 xfs_agblock_t tend; /* end block of busy extent */
1229 int i; /* success/failure of operation */
1230 unsigned busy_gen;
1231
1232 ASSERT(args->alignment == 1);
1233
1234 /*
1235 * Allocate/initialize a cursor for the by-number freespace btree.
1236 */
1237 bno_cur = xfs_bnobt_init_cursor(args->mp, args->tp, args->agbp,
1238 args->pag);
1239
1240 /*
1241 * Lookup bno and minlen in the btree (minlen is irrelevant, really).
1242 * Look for the closest free block <= bno, it must contain bno
1243 * if any free block does.
1244 */
1245 error = xfs_alloc_lookup_le(bno_cur, args->agbno, args->minlen, &i);
1246 if (error)
1247 goto error0;
1248 if (!i)
1249 goto not_found;
1250
1251 /*
1252 * Grab the freespace record.
1253 */
1254 error = xfs_alloc_get_rec(bno_cur, &fbno, &flen, &i);
1255 if (error)
1256 goto error0;
1257 if (XFS_IS_CORRUPT(args->mp, i != 1)) {
1258 xfs_btree_mark_sick(bno_cur);
1259 error = -EFSCORRUPTED;
1260 goto error0;
1261 }
1262 ASSERT(fbno <= args->agbno);
1263
1264 /*
1265 * Check for overlapping busy extents.
1266 */
1267 tbno = fbno;
1268 tlen = flen;
1269 xfs_extent_busy_trim(args, &tbno, &tlen, &busy_gen);
1270
1271 /*
1272 * Give up if the start of the extent is busy, or the freespace isn't
1273 * long enough for the minimum request.
1274 */
1275 if (tbno > args->agbno)
1276 goto not_found;
1277 if (tlen < args->minlen)
1278 goto not_found;
1279 tend = tbno + tlen;
1280 if (tend < args->agbno + args->minlen)
1281 goto not_found;
1282
1283 /*
1284 * End of extent will be smaller of the freespace end and the
1285 * maximal requested end.
1286 *
1287 * Fix the length according to mod and prod if given.
1288 */
1289 args->len = XFS_AGBLOCK_MIN(tend, args->agbno + args->maxlen)
1290 - args->agbno;
1291 xfs_alloc_fix_len(args);
1292 ASSERT(args->agbno + args->len <= tend);
1293
1294 /*
1295 * We are allocating agbno for args->len
1296 * Allocate/initialize a cursor for the by-size btree.
1297 */
1298 cnt_cur = xfs_cntbt_init_cursor(args->mp, args->tp, args->agbp,
1299 args->pag);
1300 ASSERT(args->agbno + args->len <= be32_to_cpu(agf->agf_length));
1301 error = xfs_alloc_fixup_trees(cnt_cur, bno_cur, fbno, flen, args->agbno,
1302 args->len, XFSA_FIXUP_BNO_OK);
1303 if (error) {
1304 xfs_btree_del_cursor(cnt_cur, XFS_BTREE_ERROR);
1305 goto error0;
1306 }
1307
1308 xfs_btree_del_cursor(bno_cur, XFS_BTREE_NOERROR);
1309 xfs_btree_del_cursor(cnt_cur, XFS_BTREE_NOERROR);
1310
1311 args->wasfromfl = 0;
1312 trace_xfs_alloc_exact_done(args);
1313 return 0;
1314
1315not_found:
1316 /* Didn't find it, return null. */
1317 xfs_btree_del_cursor(bno_cur, XFS_BTREE_NOERROR);
1318 args->agbno = NULLAGBLOCK;
1319 trace_xfs_alloc_exact_notfound(args);
1320 return 0;
1321
1322error0:
1323 xfs_btree_del_cursor(bno_cur, XFS_BTREE_ERROR);
1324 trace_xfs_alloc_exact_error(args);
1325 return error;
1326}
1327
1328/*
1329 * Search a given number of btree records in a given direction. Check each
1330 * record against the good extent we've already found.
1331 */
1332STATIC int
1333xfs_alloc_walk_iter(
1334 struct xfs_alloc_arg *args,
1335 struct xfs_alloc_cur *acur,
1336 struct xfs_btree_cur *cur,
1337 bool increment,
1338 bool find_one, /* quit on first candidate */
1339 int count, /* rec count (-1 for infinite) */
1340 int *stat)
1341{
1342 int error;
1343 int i;
1344
1345 *stat = 0;
1346
1347 /*
1348 * Search so long as the cursor is active or we find a better extent.
1349 * The cursor is deactivated if it extends beyond the range of the
1350 * current allocation candidate.
1351 */
1352 while (xfs_alloc_cur_active(cur) && count) {
1353 error = xfs_alloc_cur_check(args, acur, cur, &i);
1354 if (error)
1355 return error;
1356 if (i == 1) {
1357 *stat = 1;
1358 if (find_one)
1359 break;
1360 }
1361 if (!xfs_alloc_cur_active(cur))
1362 break;
1363
1364 if (increment)
1365 error = xfs_btree_increment(cur, 0, &i);
1366 else
1367 error = xfs_btree_decrement(cur, 0, &i);
1368 if (error)
1369 return error;
1370 if (i == 0)
1371 cur->bc_flags &= ~XFS_BTREE_ALLOCBT_ACTIVE;
1372
1373 if (count > 0)
1374 count--;
1375 }
1376
1377 return 0;
1378}
1379
1380/*
1381 * Search the by-bno and by-size btrees in parallel in search of an extent with
1382 * ideal locality based on the NEAR mode ->agbno locality hint.
1383 */
1384STATIC int
1385xfs_alloc_ag_vextent_locality(
1386 struct xfs_alloc_arg *args,
1387 struct xfs_alloc_cur *acur,
1388 int *stat)
1389{
1390 struct xfs_btree_cur *fbcur = NULL;
1391 int error;
1392 int i;
1393 bool fbinc;
1394
1395 ASSERT(acur->len == 0);
1396
1397 *stat = 0;
1398
1399 error = xfs_alloc_lookup_ge(acur->cnt, args->agbno, acur->cur_len, &i);
1400 if (error)
1401 return error;
1402 error = xfs_alloc_lookup_le(acur->bnolt, args->agbno, 0, &i);
1403 if (error)
1404 return error;
1405 error = xfs_alloc_lookup_ge(acur->bnogt, args->agbno, 0, &i);
1406 if (error)
1407 return error;
1408
1409 /*
1410 * Search the bnobt and cntbt in parallel. Search the bnobt left and
1411 * right and lookup the closest extent to the locality hint for each
1412 * extent size key in the cntbt. The entire search terminates
1413 * immediately on a bnobt hit because that means we've found best case
1414 * locality. Otherwise the search continues until the cntbt cursor runs
1415 * off the end of the tree. If no allocation candidate is found at this
1416 * point, give up on locality, walk backwards from the end of the cntbt
1417 * and take the first available extent.
1418 *
1419 * The parallel tree searches balance each other out to provide fairly
1420 * consistent performance for various situations. The bnobt search can
1421 * have pathological behavior in the worst case scenario of larger
1422 * allocation requests and fragmented free space. On the other hand, the
1423 * bnobt is able to satisfy most smaller allocation requests much more
1424 * quickly than the cntbt. The cntbt search can sift through fragmented
1425 * free space and sets of free extents for larger allocation requests
1426 * more quickly than the bnobt. Since the locality hint is just a hint
1427 * and we don't want to scan the entire bnobt for perfect locality, the
1428 * cntbt search essentially bounds the bnobt search such that we can
1429 * find good enough locality at reasonable performance in most cases.
1430 */
1431 while (xfs_alloc_cur_active(acur->bnolt) ||
1432 xfs_alloc_cur_active(acur->bnogt) ||
1433 xfs_alloc_cur_active(acur->cnt)) {
1434
1435 trace_xfs_alloc_cur_lookup(args);
1436
1437 /*
1438 * Search the bnobt left and right. In the case of a hit, finish
1439 * the search in the opposite direction and we're done.
1440 */
1441 error = xfs_alloc_walk_iter(args, acur, acur->bnolt, false,
1442 true, 1, &i);
1443 if (error)
1444 return error;
1445 if (i == 1) {
1446 trace_xfs_alloc_cur_left(args);
1447 fbcur = acur->bnogt;
1448 fbinc = true;
1449 break;
1450 }
1451 error = xfs_alloc_walk_iter(args, acur, acur->bnogt, true, true,
1452 1, &i);
1453 if (error)
1454 return error;
1455 if (i == 1) {
1456 trace_xfs_alloc_cur_right(args);
1457 fbcur = acur->bnolt;
1458 fbinc = false;
1459 break;
1460 }
1461
1462 /*
1463 * Check the extent with best locality based on the current
1464 * extent size search key and keep track of the best candidate.
1465 */
1466 error = xfs_alloc_cntbt_iter(args, acur);
1467 if (error)
1468 return error;
1469 if (!xfs_alloc_cur_active(acur->cnt)) {
1470 trace_xfs_alloc_cur_lookup_done(args);
1471 break;
1472 }
1473 }
1474
1475 /*
1476 * If we failed to find anything due to busy extents, return empty
1477 * handed so the caller can flush and retry. If no busy extents were
1478 * found, walk backwards from the end of the cntbt as a last resort.
1479 */
1480 if (!xfs_alloc_cur_active(acur->cnt) && !acur->len && !acur->busy) {
1481 error = xfs_btree_decrement(acur->cnt, 0, &i);
1482 if (error)
1483 return error;
1484 if (i) {
1485 acur->cnt->bc_flags |= XFS_BTREE_ALLOCBT_ACTIVE;
1486 fbcur = acur->cnt;
1487 fbinc = false;
1488 }
1489 }
1490
1491 /*
1492 * Search in the opposite direction for a better entry in the case of
1493 * a bnobt hit or walk backwards from the end of the cntbt.
1494 */
1495 if (fbcur) {
1496 error = xfs_alloc_walk_iter(args, acur, fbcur, fbinc, true, -1,
1497 &i);
1498 if (error)
1499 return error;
1500 }
1501
1502 if (acur->len)
1503 *stat = 1;
1504
1505 return 0;
1506}
1507
1508/* Check the last block of the cnt btree for allocations. */
1509static int
1510xfs_alloc_ag_vextent_lastblock(
1511 struct xfs_alloc_arg *args,
1512 struct xfs_alloc_cur *acur,
1513 xfs_agblock_t *bno,
1514 xfs_extlen_t *len,
1515 bool *allocated)
1516{
1517 int error;
1518 int i;
1519
1520#ifdef DEBUG
1521 /* Randomly don't execute the first algorithm. */
1522 if (get_random_u32_below(2))
1523 return 0;
1524#endif
1525
1526 /*
1527 * Start from the entry that lookup found, sequence through all larger
1528 * free blocks. If we're actually pointing at a record smaller than
1529 * maxlen, go to the start of this block, and skip all those smaller
1530 * than minlen.
1531 */
1532 if (*len || args->alignment > 1) {
1533 acur->cnt->bc_levels[0].ptr = 1;
1534 do {
1535 error = xfs_alloc_get_rec(acur->cnt, bno, len, &i);
1536 if (error)
1537 return error;
1538 if (XFS_IS_CORRUPT(args->mp, i != 1)) {
1539 xfs_btree_mark_sick(acur->cnt);
1540 return -EFSCORRUPTED;
1541 }
1542 if (*len >= args->minlen)
1543 break;
1544 error = xfs_btree_increment(acur->cnt, 0, &i);
1545 if (error)
1546 return error;
1547 } while (i);
1548 ASSERT(*len >= args->minlen);
1549 if (!i)
1550 return 0;
1551 }
1552
1553 error = xfs_alloc_walk_iter(args, acur, acur->cnt, true, false, -1, &i);
1554 if (error)
1555 return error;
1556
1557 /*
1558 * It didn't work. We COULD be in a case where there's a good record
1559 * somewhere, so try again.
1560 */
1561 if (acur->len == 0)
1562 return 0;
1563
1564 trace_xfs_alloc_near_first(args);
1565 *allocated = true;
1566 return 0;
1567}
1568
1569/*
1570 * Allocate a variable extent near bno in the allocation group agno.
1571 * Extent's length (returned in len) will be between minlen and maxlen,
1572 * and of the form k * prod + mod unless there's nothing that large.
1573 * Return the starting a.g. block, or NULLAGBLOCK if we can't do it.
1574 */
1575STATIC int
1576xfs_alloc_ag_vextent_near(
1577 struct xfs_alloc_arg *args,
1578 uint32_t alloc_flags)
1579{
1580 struct xfs_alloc_cur acur = {};
1581 int error; /* error code */
1582 int i; /* result code, temporary */
1583 xfs_agblock_t bno;
1584 xfs_extlen_t len;
1585
1586 /* handle uninitialized agbno range so caller doesn't have to */
1587 if (!args->min_agbno && !args->max_agbno)
1588 args->max_agbno = args->mp->m_sb.sb_agblocks - 1;
1589 ASSERT(args->min_agbno <= args->max_agbno);
1590
1591 /* clamp agbno to the range if it's outside */
1592 if (args->agbno < args->min_agbno)
1593 args->agbno = args->min_agbno;
1594 if (args->agbno > args->max_agbno)
1595 args->agbno = args->max_agbno;
1596
1597 /* Retry once quickly if we find busy extents before blocking. */
1598 alloc_flags |= XFS_ALLOC_FLAG_TRYFLUSH;
1599restart:
1600 len = 0;
1601
1602 /*
1603 * Set up cursors and see if there are any free extents as big as
1604 * maxlen. If not, pick the last entry in the tree unless the tree is
1605 * empty.
1606 */
1607 error = xfs_alloc_cur_setup(args, &acur);
1608 if (error == -ENOSPC) {
1609 error = xfs_alloc_ag_vextent_small(args, acur.cnt, &bno,
1610 &len, &i);
1611 if (error)
1612 goto out;
1613 if (i == 0 || len == 0) {
1614 trace_xfs_alloc_near_noentry(args);
1615 goto out;
1616 }
1617 ASSERT(i == 1);
1618 } else if (error) {
1619 goto out;
1620 }
1621
1622 /*
1623 * First algorithm.
1624 * If the requested extent is large wrt the freespaces available
1625 * in this a.g., then the cursor will be pointing to a btree entry
1626 * near the right edge of the tree. If it's in the last btree leaf
1627 * block, then we just examine all the entries in that block
1628 * that are big enough, and pick the best one.
1629 */
1630 if (xfs_btree_islastblock(acur.cnt, 0)) {
1631 bool allocated = false;
1632
1633 error = xfs_alloc_ag_vextent_lastblock(args, &acur, &bno, &len,
1634 &allocated);
1635 if (error)
1636 goto out;
1637 if (allocated)
1638 goto alloc_finish;
1639 }
1640
1641 /*
1642 * Second algorithm. Combined cntbt and bnobt search to find ideal
1643 * locality.
1644 */
1645 error = xfs_alloc_ag_vextent_locality(args, &acur, &i);
1646 if (error)
1647 goto out;
1648
1649 /*
1650 * If we couldn't get anything, give up.
1651 */
1652 if (!acur.len) {
1653 if (acur.busy) {
1654 /*
1655 * Our only valid extents must have been busy. Flush and
1656 * retry the allocation again. If we get an -EAGAIN
1657 * error, we're being told that a deadlock was avoided
1658 * and the current transaction needs committing before
1659 * the allocation can be retried.
1660 */
1661 trace_xfs_alloc_near_busy(args);
1662 error = xfs_extent_busy_flush(args->tp, args->pag,
1663 acur.busy_gen, alloc_flags);
1664 if (error)
1665 goto out;
1666
1667 alloc_flags &= ~XFS_ALLOC_FLAG_TRYFLUSH;
1668 goto restart;
1669 }
1670 trace_xfs_alloc_size_neither(args);
1671 args->agbno = NULLAGBLOCK;
1672 goto out;
1673 }
1674
1675alloc_finish:
1676 /* fix up btrees on a successful allocation */
1677 error = xfs_alloc_cur_finish(args, &acur);
1678
1679out:
1680 xfs_alloc_cur_close(&acur, error);
1681 return error;
1682}
1683
1684/*
1685 * Allocate a variable extent anywhere in the allocation group agno.
1686 * Extent's length (returned in len) will be between minlen and maxlen,
1687 * and of the form k * prod + mod unless there's nothing that large.
1688 * Return the starting a.g. block, or NULLAGBLOCK if we can't do it.
1689 */
1690static int
1691xfs_alloc_ag_vextent_size(
1692 struct xfs_alloc_arg *args,
1693 uint32_t alloc_flags)
1694{
1695 struct xfs_agf *agf = args->agbp->b_addr;
1696 struct xfs_btree_cur *bno_cur;
1697 struct xfs_btree_cur *cnt_cur;
1698 xfs_agblock_t fbno; /* start of found freespace */
1699 xfs_extlen_t flen; /* length of found freespace */
1700 xfs_agblock_t rbno; /* returned block number */
1701 xfs_extlen_t rlen; /* length of returned extent */
1702 bool busy;
1703 unsigned busy_gen;
1704 int error;
1705 int i;
1706
1707 /* Retry once quickly if we find busy extents before blocking. */
1708 alloc_flags |= XFS_ALLOC_FLAG_TRYFLUSH;
1709restart:
1710 /*
1711 * Allocate and initialize a cursor for the by-size btree.
1712 */
1713 cnt_cur = xfs_cntbt_init_cursor(args->mp, args->tp, args->agbp,
1714 args->pag);
1715 bno_cur = NULL;
1716
1717 /*
1718 * Look for an entry >= maxlen+alignment-1 blocks.
1719 */
1720 if ((error = xfs_alloc_lookup_ge(cnt_cur, 0,
1721 args->maxlen + args->alignment - 1, &i)))
1722 goto error0;
1723
1724 /*
1725 * If none then we have to settle for a smaller extent. In the case that
1726 * there are no large extents, this will return the last entry in the
1727 * tree unless the tree is empty. In the case that there are only busy
1728 * large extents, this will return the largest small extent unless there
1729 * are no smaller extents available.
1730 */
1731 if (!i) {
1732 error = xfs_alloc_ag_vextent_small(args, cnt_cur,
1733 &fbno, &flen, &i);
1734 if (error)
1735 goto error0;
1736 if (i == 0 || flen == 0) {
1737 xfs_btree_del_cursor(cnt_cur, XFS_BTREE_NOERROR);
1738 trace_xfs_alloc_size_noentry(args);
1739 return 0;
1740 }
1741 ASSERT(i == 1);
1742 busy = xfs_alloc_compute_aligned(args, fbno, flen, &rbno,
1743 &rlen, &busy_gen);
1744 } else {
1745 /*
1746 * Search for a non-busy extent that is large enough.
1747 */
1748 for (;;) {
1749 error = xfs_alloc_get_rec(cnt_cur, &fbno, &flen, &i);
1750 if (error)
1751 goto error0;
1752 if (XFS_IS_CORRUPT(args->mp, i != 1)) {
1753 xfs_btree_mark_sick(cnt_cur);
1754 error = -EFSCORRUPTED;
1755 goto error0;
1756 }
1757
1758 busy = xfs_alloc_compute_aligned(args, fbno, flen,
1759 &rbno, &rlen, &busy_gen);
1760
1761 if (rlen >= args->maxlen)
1762 break;
1763
1764 error = xfs_btree_increment(cnt_cur, 0, &i);
1765 if (error)
1766 goto error0;
1767 if (i)
1768 continue;
1769
1770 /*
1771 * Our only valid extents must have been busy. Flush and
1772 * retry the allocation again. If we get an -EAGAIN
1773 * error, we're being told that a deadlock was avoided
1774 * and the current transaction needs committing before
1775 * the allocation can be retried.
1776 */
1777 trace_xfs_alloc_size_busy(args);
1778 error = xfs_extent_busy_flush(args->tp, args->pag,
1779 busy_gen, alloc_flags);
1780 if (error)
1781 goto error0;
1782
1783 alloc_flags &= ~XFS_ALLOC_FLAG_TRYFLUSH;
1784 xfs_btree_del_cursor(cnt_cur, XFS_BTREE_NOERROR);
1785 goto restart;
1786 }
1787 }
1788
1789 /*
1790 * In the first case above, we got the last entry in the
1791 * by-size btree. Now we check to see if the space hits maxlen
1792 * once aligned; if not, we search left for something better.
1793 * This can't happen in the second case above.
1794 */
1795 rlen = XFS_EXTLEN_MIN(args->maxlen, rlen);
1796 if (XFS_IS_CORRUPT(args->mp,
1797 rlen != 0 &&
1798 (rlen > flen ||
1799 rbno + rlen > fbno + flen))) {
1800 xfs_btree_mark_sick(cnt_cur);
1801 error = -EFSCORRUPTED;
1802 goto error0;
1803 }
1804 if (rlen < args->maxlen) {
1805 xfs_agblock_t bestfbno;
1806 xfs_extlen_t bestflen;
1807 xfs_agblock_t bestrbno;
1808 xfs_extlen_t bestrlen;
1809
1810 bestrlen = rlen;
1811 bestrbno = rbno;
1812 bestflen = flen;
1813 bestfbno = fbno;
1814 for (;;) {
1815 if ((error = xfs_btree_decrement(cnt_cur, 0, &i)))
1816 goto error0;
1817 if (i == 0)
1818 break;
1819 if ((error = xfs_alloc_get_rec(cnt_cur, &fbno, &flen,
1820 &i)))
1821 goto error0;
1822 if (XFS_IS_CORRUPT(args->mp, i != 1)) {
1823 xfs_btree_mark_sick(cnt_cur);
1824 error = -EFSCORRUPTED;
1825 goto error0;
1826 }
1827 if (flen < bestrlen)
1828 break;
1829 busy = xfs_alloc_compute_aligned(args, fbno, flen,
1830 &rbno, &rlen, &busy_gen);
1831 rlen = XFS_EXTLEN_MIN(args->maxlen, rlen);
1832 if (XFS_IS_CORRUPT(args->mp,
1833 rlen != 0 &&
1834 (rlen > flen ||
1835 rbno + rlen > fbno + flen))) {
1836 xfs_btree_mark_sick(cnt_cur);
1837 error = -EFSCORRUPTED;
1838 goto error0;
1839 }
1840 if (rlen > bestrlen) {
1841 bestrlen = rlen;
1842 bestrbno = rbno;
1843 bestflen = flen;
1844 bestfbno = fbno;
1845 if (rlen == args->maxlen)
1846 break;
1847 }
1848 }
1849 if ((error = xfs_alloc_lookup_eq(cnt_cur, bestfbno, bestflen,
1850 &i)))
1851 goto error0;
1852 if (XFS_IS_CORRUPT(args->mp, i != 1)) {
1853 xfs_btree_mark_sick(cnt_cur);
1854 error = -EFSCORRUPTED;
1855 goto error0;
1856 }
1857 rlen = bestrlen;
1858 rbno = bestrbno;
1859 flen = bestflen;
1860 fbno = bestfbno;
1861 }
1862 args->wasfromfl = 0;
1863 /*
1864 * Fix up the length.
1865 */
1866 args->len = rlen;
1867 if (rlen < args->minlen) {
1868 if (busy) {
1869 /*
1870 * Our only valid extents must have been busy. Flush and
1871 * retry the allocation again. If we get an -EAGAIN
1872 * error, we're being told that a deadlock was avoided
1873 * and the current transaction needs committing before
1874 * the allocation can be retried.
1875 */
1876 trace_xfs_alloc_size_busy(args);
1877 error = xfs_extent_busy_flush(args->tp, args->pag,
1878 busy_gen, alloc_flags);
1879 if (error)
1880 goto error0;
1881
1882 alloc_flags &= ~XFS_ALLOC_FLAG_TRYFLUSH;
1883 xfs_btree_del_cursor(cnt_cur, XFS_BTREE_NOERROR);
1884 goto restart;
1885 }
1886 goto out_nominleft;
1887 }
1888 xfs_alloc_fix_len(args);
1889
1890 rlen = args->len;
1891 if (XFS_IS_CORRUPT(args->mp, rlen > flen)) {
1892 xfs_btree_mark_sick(cnt_cur);
1893 error = -EFSCORRUPTED;
1894 goto error0;
1895 }
1896 /*
1897 * Allocate and initialize a cursor for the by-block tree.
1898 */
1899 bno_cur = xfs_bnobt_init_cursor(args->mp, args->tp, args->agbp,
1900 args->pag);
1901 if ((error = xfs_alloc_fixup_trees(cnt_cur, bno_cur, fbno, flen,
1902 rbno, rlen, XFSA_FIXUP_CNT_OK)))
1903 goto error0;
1904 xfs_btree_del_cursor(cnt_cur, XFS_BTREE_NOERROR);
1905 xfs_btree_del_cursor(bno_cur, XFS_BTREE_NOERROR);
1906 cnt_cur = bno_cur = NULL;
1907 args->len = rlen;
1908 args->agbno = rbno;
1909 if (XFS_IS_CORRUPT(args->mp,
1910 args->agbno + args->len >
1911 be32_to_cpu(agf->agf_length))) {
1912 xfs_ag_mark_sick(args->pag, XFS_SICK_AG_BNOBT);
1913 error = -EFSCORRUPTED;
1914 goto error0;
1915 }
1916 trace_xfs_alloc_size_done(args);
1917 return 0;
1918
1919error0:
1920 trace_xfs_alloc_size_error(args);
1921 if (cnt_cur)
1922 xfs_btree_del_cursor(cnt_cur, XFS_BTREE_ERROR);
1923 if (bno_cur)
1924 xfs_btree_del_cursor(bno_cur, XFS_BTREE_ERROR);
1925 return error;
1926
1927out_nominleft:
1928 xfs_btree_del_cursor(cnt_cur, XFS_BTREE_NOERROR);
1929 trace_xfs_alloc_size_nominleft(args);
1930 args->agbno = NULLAGBLOCK;
1931 return 0;
1932}
1933
1934/*
1935 * Free the extent starting at agno/bno for length.
1936 */
1937STATIC int
1938xfs_free_ag_extent(
1939 struct xfs_trans *tp,
1940 struct xfs_buf *agbp,
1941 xfs_agnumber_t agno,
1942 xfs_agblock_t bno,
1943 xfs_extlen_t len,
1944 const struct xfs_owner_info *oinfo,
1945 enum xfs_ag_resv_type type)
1946{
1947 struct xfs_mount *mp;
1948 struct xfs_btree_cur *bno_cur;
1949 struct xfs_btree_cur *cnt_cur;
1950 xfs_agblock_t gtbno; /* start of right neighbor */
1951 xfs_extlen_t gtlen; /* length of right neighbor */
1952 xfs_agblock_t ltbno; /* start of left neighbor */
1953 xfs_extlen_t ltlen; /* length of left neighbor */
1954 xfs_agblock_t nbno; /* new starting block of freesp */
1955 xfs_extlen_t nlen; /* new length of freespace */
1956 int haveleft; /* have a left neighbor */
1957 int haveright; /* have a right neighbor */
1958 int i;
1959 int error;
1960 struct xfs_perag *pag = agbp->b_pag;
1961
1962 bno_cur = cnt_cur = NULL;
1963 mp = tp->t_mountp;
1964
1965 if (!xfs_rmap_should_skip_owner_update(oinfo)) {
1966 error = xfs_rmap_free(tp, agbp, pag, bno, len, oinfo);
1967 if (error)
1968 goto error0;
1969 }
1970
1971 /*
1972 * Allocate and initialize a cursor for the by-block btree.
1973 */
1974 bno_cur = xfs_bnobt_init_cursor(mp, tp, agbp, pag);
1975 /*
1976 * Look for a neighboring block on the left (lower block numbers)
1977 * that is contiguous with this space.
1978 */
1979 if ((error = xfs_alloc_lookup_le(bno_cur, bno, len, &haveleft)))
1980 goto error0;
1981 if (haveleft) {
1982 /*
1983 * There is a block to our left.
1984 */
1985 if ((error = xfs_alloc_get_rec(bno_cur, <bno, <len, &i)))
1986 goto error0;
1987 if (XFS_IS_CORRUPT(mp, i != 1)) {
1988 xfs_btree_mark_sick(bno_cur);
1989 error = -EFSCORRUPTED;
1990 goto error0;
1991 }
1992 /*
1993 * It's not contiguous, though.
1994 */
1995 if (ltbno + ltlen < bno)
1996 haveleft = 0;
1997 else {
1998 /*
1999 * If this failure happens the request to free this
2000 * space was invalid, it's (partly) already free.
2001 * Very bad.
2002 */
2003 if (XFS_IS_CORRUPT(mp, ltbno + ltlen > bno)) {
2004 xfs_btree_mark_sick(bno_cur);
2005 error = -EFSCORRUPTED;
2006 goto error0;
2007 }
2008 }
2009 }
2010 /*
2011 * Look for a neighboring block on the right (higher block numbers)
2012 * that is contiguous with this space.
2013 */
2014 if ((error = xfs_btree_increment(bno_cur, 0, &haveright)))
2015 goto error0;
2016 if (haveright) {
2017 /*
2018 * There is a block to our right.
2019 */
2020 if ((error = xfs_alloc_get_rec(bno_cur, >bno, >len, &i)))
2021 goto error0;
2022 if (XFS_IS_CORRUPT(mp, i != 1)) {
2023 xfs_btree_mark_sick(bno_cur);
2024 error = -EFSCORRUPTED;
2025 goto error0;
2026 }
2027 /*
2028 * It's not contiguous, though.
2029 */
2030 if (bno + len < gtbno)
2031 haveright = 0;
2032 else {
2033 /*
2034 * If this failure happens the request to free this
2035 * space was invalid, it's (partly) already free.
2036 * Very bad.
2037 */
2038 if (XFS_IS_CORRUPT(mp, bno + len > gtbno)) {
2039 xfs_btree_mark_sick(bno_cur);
2040 error = -EFSCORRUPTED;
2041 goto error0;
2042 }
2043 }
2044 }
2045 /*
2046 * Now allocate and initialize a cursor for the by-size tree.
2047 */
2048 cnt_cur = xfs_cntbt_init_cursor(mp, tp, agbp, pag);
2049 /*
2050 * Have both left and right contiguous neighbors.
2051 * Merge all three into a single free block.
2052 */
2053 if (haveleft && haveright) {
2054 /*
2055 * Delete the old by-size entry on the left.
2056 */
2057 if ((error = xfs_alloc_lookup_eq(cnt_cur, ltbno, ltlen, &i)))
2058 goto error0;
2059 if (XFS_IS_CORRUPT(mp, i != 1)) {
2060 xfs_btree_mark_sick(cnt_cur);
2061 error = -EFSCORRUPTED;
2062 goto error0;
2063 }
2064 if ((error = xfs_btree_delete(cnt_cur, &i)))
2065 goto error0;
2066 if (XFS_IS_CORRUPT(mp, i != 1)) {
2067 xfs_btree_mark_sick(cnt_cur);
2068 error = -EFSCORRUPTED;
2069 goto error0;
2070 }
2071 /*
2072 * Delete the old by-size entry on the right.
2073 */
2074 if ((error = xfs_alloc_lookup_eq(cnt_cur, gtbno, gtlen, &i)))
2075 goto error0;
2076 if (XFS_IS_CORRUPT(mp, i != 1)) {
2077 xfs_btree_mark_sick(cnt_cur);
2078 error = -EFSCORRUPTED;
2079 goto error0;
2080 }
2081 if ((error = xfs_btree_delete(cnt_cur, &i)))
2082 goto error0;
2083 if (XFS_IS_CORRUPT(mp, i != 1)) {
2084 xfs_btree_mark_sick(cnt_cur);
2085 error = -EFSCORRUPTED;
2086 goto error0;
2087 }
2088 /*
2089 * Delete the old by-block entry for the right block.
2090 */
2091 if ((error = xfs_btree_delete(bno_cur, &i)))
2092 goto error0;
2093 if (XFS_IS_CORRUPT(mp, i != 1)) {
2094 xfs_btree_mark_sick(bno_cur);
2095 error = -EFSCORRUPTED;
2096 goto error0;
2097 }
2098 /*
2099 * Move the by-block cursor back to the left neighbor.
2100 */
2101 if ((error = xfs_btree_decrement(bno_cur, 0, &i)))
2102 goto error0;
2103 if (XFS_IS_CORRUPT(mp, i != 1)) {
2104 xfs_btree_mark_sick(bno_cur);
2105 error = -EFSCORRUPTED;
2106 goto error0;
2107 }
2108#ifdef DEBUG
2109 /*
2110 * Check that this is the right record: delete didn't
2111 * mangle the cursor.
2112 */
2113 {
2114 xfs_agblock_t xxbno;
2115 xfs_extlen_t xxlen;
2116
2117 if ((error = xfs_alloc_get_rec(bno_cur, &xxbno, &xxlen,
2118 &i)))
2119 goto error0;
2120 if (XFS_IS_CORRUPT(mp,
2121 i != 1 ||
2122 xxbno != ltbno ||
2123 xxlen != ltlen)) {
2124 xfs_btree_mark_sick(bno_cur);
2125 error = -EFSCORRUPTED;
2126 goto error0;
2127 }
2128 }
2129#endif
2130 /*
2131 * Update remaining by-block entry to the new, joined block.
2132 */
2133 nbno = ltbno;
2134 nlen = len + ltlen + gtlen;
2135 if ((error = xfs_alloc_update(bno_cur, nbno, nlen)))
2136 goto error0;
2137 }
2138 /*
2139 * Have only a left contiguous neighbor.
2140 * Merge it together with the new freespace.
2141 */
2142 else if (haveleft) {
2143 /*
2144 * Delete the old by-size entry on the left.
2145 */
2146 if ((error = xfs_alloc_lookup_eq(cnt_cur, ltbno, ltlen, &i)))
2147 goto error0;
2148 if (XFS_IS_CORRUPT(mp, i != 1)) {
2149 xfs_btree_mark_sick(cnt_cur);
2150 error = -EFSCORRUPTED;
2151 goto error0;
2152 }
2153 if ((error = xfs_btree_delete(cnt_cur, &i)))
2154 goto error0;
2155 if (XFS_IS_CORRUPT(mp, i != 1)) {
2156 xfs_btree_mark_sick(cnt_cur);
2157 error = -EFSCORRUPTED;
2158 goto error0;
2159 }
2160 /*
2161 * Back up the by-block cursor to the left neighbor, and
2162 * update its length.
2163 */
2164 if ((error = xfs_btree_decrement(bno_cur, 0, &i)))
2165 goto error0;
2166 if (XFS_IS_CORRUPT(mp, i != 1)) {
2167 xfs_btree_mark_sick(bno_cur);
2168 error = -EFSCORRUPTED;
2169 goto error0;
2170 }
2171 nbno = ltbno;
2172 nlen = len + ltlen;
2173 if ((error = xfs_alloc_update(bno_cur, nbno, nlen)))
2174 goto error0;
2175 }
2176 /*
2177 * Have only a right contiguous neighbor.
2178 * Merge it together with the new freespace.
2179 */
2180 else if (haveright) {
2181 /*
2182 * Delete the old by-size entry on the right.
2183 */
2184 if ((error = xfs_alloc_lookup_eq(cnt_cur, gtbno, gtlen, &i)))
2185 goto error0;
2186 if (XFS_IS_CORRUPT(mp, i != 1)) {
2187 xfs_btree_mark_sick(cnt_cur);
2188 error = -EFSCORRUPTED;
2189 goto error0;
2190 }
2191 if ((error = xfs_btree_delete(cnt_cur, &i)))
2192 goto error0;
2193 if (XFS_IS_CORRUPT(mp, i != 1)) {
2194 xfs_btree_mark_sick(cnt_cur);
2195 error = -EFSCORRUPTED;
2196 goto error0;
2197 }
2198 /*
2199 * Update the starting block and length of the right
2200 * neighbor in the by-block tree.
2201 */
2202 nbno = bno;
2203 nlen = len + gtlen;
2204 if ((error = xfs_alloc_update(bno_cur, nbno, nlen)))
2205 goto error0;
2206 }
2207 /*
2208 * No contiguous neighbors.
2209 * Insert the new freespace into the by-block tree.
2210 */
2211 else {
2212 nbno = bno;
2213 nlen = len;
2214 if ((error = xfs_btree_insert(bno_cur, &i)))
2215 goto error0;
2216 if (XFS_IS_CORRUPT(mp, i != 1)) {
2217 xfs_btree_mark_sick(bno_cur);
2218 error = -EFSCORRUPTED;
2219 goto error0;
2220 }
2221 }
2222 xfs_btree_del_cursor(bno_cur, XFS_BTREE_NOERROR);
2223 bno_cur = NULL;
2224 /*
2225 * In all cases we need to insert the new freespace in the by-size tree.
2226 */
2227 if ((error = xfs_alloc_lookup_eq(cnt_cur, nbno, nlen, &i)))
2228 goto error0;
2229 if (XFS_IS_CORRUPT(mp, i != 0)) {
2230 xfs_btree_mark_sick(cnt_cur);
2231 error = -EFSCORRUPTED;
2232 goto error0;
2233 }
2234 if ((error = xfs_btree_insert(cnt_cur, &i)))
2235 goto error0;
2236 if (XFS_IS_CORRUPT(mp, i != 1)) {
2237 xfs_btree_mark_sick(cnt_cur);
2238 error = -EFSCORRUPTED;
2239 goto error0;
2240 }
2241 xfs_btree_del_cursor(cnt_cur, XFS_BTREE_NOERROR);
2242 cnt_cur = NULL;
2243
2244 /*
2245 * Update the freespace totals in the ag and superblock.
2246 */
2247 error = xfs_alloc_update_counters(tp, agbp, len);
2248 xfs_ag_resv_free_extent(agbp->b_pag, type, tp, len);
2249 if (error)
2250 goto error0;
2251
2252 XFS_STATS_INC(mp, xs_freex);
2253 XFS_STATS_ADD(mp, xs_freeb, len);
2254
2255 trace_xfs_free_extent(mp, agno, bno, len, type, haveleft, haveright);
2256
2257 return 0;
2258
2259 error0:
2260 trace_xfs_free_extent(mp, agno, bno, len, type, -1, -1);
2261 if (bno_cur)
2262 xfs_btree_del_cursor(bno_cur, XFS_BTREE_ERROR);
2263 if (cnt_cur)
2264 xfs_btree_del_cursor(cnt_cur, XFS_BTREE_ERROR);
2265 return error;
2266}
2267
2268/*
2269 * Visible (exported) allocation/free functions.
2270 * Some of these are used just by xfs_alloc_btree.c and this file.
2271 */
2272
2273/*
2274 * Compute and fill in value of m_alloc_maxlevels.
2275 */
2276void
2277xfs_alloc_compute_maxlevels(
2278 xfs_mount_t *mp) /* file system mount structure */
2279{
2280 mp->m_alloc_maxlevels = xfs_btree_compute_maxlevels(mp->m_alloc_mnr,
2281 (mp->m_sb.sb_agblocks + 1) / 2);
2282 ASSERT(mp->m_alloc_maxlevels <= xfs_allocbt_maxlevels_ondisk());
2283}
2284
2285/*
2286 * Find the length of the longest extent in an AG. The 'need' parameter
2287 * specifies how much space we're going to need for the AGFL and the
2288 * 'reserved' parameter tells us how many blocks in this AG are reserved for
2289 * other callers.
2290 */
2291xfs_extlen_t
2292xfs_alloc_longest_free_extent(
2293 struct xfs_perag *pag,
2294 xfs_extlen_t need,
2295 xfs_extlen_t reserved)
2296{
2297 xfs_extlen_t delta = 0;
2298
2299 /*
2300 * If the AGFL needs a recharge, we'll have to subtract that from the
2301 * longest extent.
2302 */
2303 if (need > pag->pagf_flcount)
2304 delta = need - pag->pagf_flcount;
2305
2306 /*
2307 * If we cannot maintain others' reservations with space from the
2308 * not-longest freesp extents, we'll have to subtract /that/ from
2309 * the longest extent too.
2310 */
2311 if (pag->pagf_freeblks - pag->pagf_longest < reserved)
2312 delta += reserved - (pag->pagf_freeblks - pag->pagf_longest);
2313
2314 /*
2315 * If the longest extent is long enough to satisfy all the
2316 * reservations and AGFL rules in place, we can return this extent.
2317 */
2318 if (pag->pagf_longest > delta)
2319 return min_t(xfs_extlen_t, pag->pag_mount->m_ag_max_usable,
2320 pag->pagf_longest - delta);
2321
2322 /* Otherwise, let the caller try for 1 block if there's space. */
2323 return pag->pagf_flcount > 0 || pag->pagf_longest > 0;
2324}
2325
2326/*
2327 * Compute the minimum length of the AGFL in the given AG. If @pag is NULL,
2328 * return the largest possible minimum length.
2329 */
2330unsigned int
2331xfs_alloc_min_freelist(
2332 struct xfs_mount *mp,
2333 struct xfs_perag *pag)
2334{
2335 /* AG btrees have at least 1 level. */
2336 const unsigned int bno_level = pag ? pag->pagf_bno_level : 1;
2337 const unsigned int cnt_level = pag ? pag->pagf_cnt_level : 1;
2338 const unsigned int rmap_level = pag ? pag->pagf_rmap_level : 1;
2339 unsigned int min_free;
2340
2341 ASSERT(mp->m_alloc_maxlevels > 0);
2342
2343 /*
2344 * For a btree shorter than the maximum height, the worst case is that
2345 * every level gets split and a new level is added, then while inserting
2346 * another entry to refill the AGFL, every level under the old root gets
2347 * split again. This is:
2348 *
2349 * (full height split reservation) + (AGFL refill split height)
2350 * = (current height + 1) + (current height - 1)
2351 * = (new height) + (new height - 2)
2352 * = 2 * new height - 2
2353 *
2354 * For a btree of maximum height, the worst case is that every level
2355 * under the root gets split, then while inserting another entry to
2356 * refill the AGFL, every level under the root gets split again. This is
2357 * also:
2358 *
2359 * 2 * (current height - 1)
2360 * = 2 * (new height - 1)
2361 * = 2 * new height - 2
2362 */
2363
2364 /* space needed by-bno freespace btree */
2365 min_free = min(bno_level + 1, mp->m_alloc_maxlevels) * 2 - 2;
2366 /* space needed by-size freespace btree */
2367 min_free += min(cnt_level + 1, mp->m_alloc_maxlevels) * 2 - 2;
2368 /* space needed reverse mapping used space btree */
2369 if (xfs_has_rmapbt(mp))
2370 min_free += min(rmap_level + 1, mp->m_rmap_maxlevels) * 2 - 2;
2371 return min_free;
2372}
2373
2374/*
2375 * Check if the operation we are fixing up the freelist for should go ahead or
2376 * not. If we are freeing blocks, we always allow it, otherwise the allocation
2377 * is dependent on whether the size and shape of free space available will
2378 * permit the requested allocation to take place.
2379 */
2380static bool
2381xfs_alloc_space_available(
2382 struct xfs_alloc_arg *args,
2383 xfs_extlen_t min_free,
2384 int flags)
2385{
2386 struct xfs_perag *pag = args->pag;
2387 xfs_extlen_t alloc_len, longest;
2388 xfs_extlen_t reservation; /* blocks that are still reserved */
2389 int available;
2390 xfs_extlen_t agflcount;
2391
2392 if (flags & XFS_ALLOC_FLAG_FREEING)
2393 return true;
2394
2395 reservation = xfs_ag_resv_needed(pag, args->resv);
2396
2397 /* do we have enough contiguous free space for the allocation? */
2398 alloc_len = args->minlen + (args->alignment - 1) + args->minalignslop;
2399 longest = xfs_alloc_longest_free_extent(pag, min_free, reservation);
2400 if (longest < alloc_len)
2401 return false;
2402
2403 /*
2404 * Do we have enough free space remaining for the allocation? Don't
2405 * account extra agfl blocks because we are about to defer free them,
2406 * making them unavailable until the current transaction commits.
2407 */
2408 agflcount = min_t(xfs_extlen_t, pag->pagf_flcount, min_free);
2409 available = (int)(pag->pagf_freeblks + agflcount -
2410 reservation - min_free - args->minleft);
2411 if (available < (int)max(args->total, alloc_len))
2412 return false;
2413
2414 /*
2415 * Clamp maxlen to the amount of free space available for the actual
2416 * extent allocation.
2417 */
2418 if (available < (int)args->maxlen && !(flags & XFS_ALLOC_FLAG_CHECK)) {
2419 args->maxlen = available;
2420 ASSERT(args->maxlen > 0);
2421 ASSERT(args->maxlen >= args->minlen);
2422 }
2423
2424 return true;
2425}
2426
2427int
2428xfs_free_agfl_block(
2429 struct xfs_trans *tp,
2430 xfs_agnumber_t agno,
2431 xfs_agblock_t agbno,
2432 struct xfs_buf *agbp,
2433 struct xfs_owner_info *oinfo)
2434{
2435 int error;
2436 struct xfs_buf *bp;
2437
2438 error = xfs_free_ag_extent(tp, agbp, agno, agbno, 1, oinfo,
2439 XFS_AG_RESV_AGFL);
2440 if (error)
2441 return error;
2442
2443 error = xfs_trans_get_buf(tp, tp->t_mountp->m_ddev_targp,
2444 XFS_AGB_TO_DADDR(tp->t_mountp, agno, agbno),
2445 tp->t_mountp->m_bsize, 0, &bp);
2446 if (error)
2447 return error;
2448 xfs_trans_binval(tp, bp);
2449
2450 return 0;
2451}
2452
2453/*
2454 * Check the agfl fields of the agf for inconsistency or corruption.
2455 *
2456 * The original purpose was to detect an agfl header padding mismatch between
2457 * current and early v5 kernels. This problem manifests as a 1-slot size
2458 * difference between the on-disk flcount and the active [first, last] range of
2459 * a wrapped agfl.
2460 *
2461 * However, we need to use these same checks to catch agfl count corruptions
2462 * unrelated to padding. This could occur on any v4 or v5 filesystem, so either
2463 * way, we need to reset the agfl and warn the user.
2464 *
2465 * Return true if a reset is required before the agfl can be used, false
2466 * otherwise.
2467 */
2468static bool
2469xfs_agfl_needs_reset(
2470 struct xfs_mount *mp,
2471 struct xfs_agf *agf)
2472{
2473 uint32_t f = be32_to_cpu(agf->agf_flfirst);
2474 uint32_t l = be32_to_cpu(agf->agf_fllast);
2475 uint32_t c = be32_to_cpu(agf->agf_flcount);
2476 int agfl_size = xfs_agfl_size(mp);
2477 int active;
2478
2479 /*
2480 * The agf read verifier catches severe corruption of these fields.
2481 * Repeat some sanity checks to cover a packed -> unpacked mismatch if
2482 * the verifier allows it.
2483 */
2484 if (f >= agfl_size || l >= agfl_size)
2485 return true;
2486 if (c > agfl_size)
2487 return true;
2488
2489 /*
2490 * Check consistency between the on-disk count and the active range. An
2491 * agfl padding mismatch manifests as an inconsistent flcount.
2492 */
2493 if (c && l >= f)
2494 active = l - f + 1;
2495 else if (c)
2496 active = agfl_size - f + l + 1;
2497 else
2498 active = 0;
2499
2500 return active != c;
2501}
2502
2503/*
2504 * Reset the agfl to an empty state. Ignore/drop any existing blocks since the
2505 * agfl content cannot be trusted. Warn the user that a repair is required to
2506 * recover leaked blocks.
2507 *
2508 * The purpose of this mechanism is to handle filesystems affected by the agfl
2509 * header padding mismatch problem. A reset keeps the filesystem online with a
2510 * relatively minor free space accounting inconsistency rather than suffer the
2511 * inevitable crash from use of an invalid agfl block.
2512 */
2513static void
2514xfs_agfl_reset(
2515 struct xfs_trans *tp,
2516 struct xfs_buf *agbp,
2517 struct xfs_perag *pag)
2518{
2519 struct xfs_mount *mp = tp->t_mountp;
2520 struct xfs_agf *agf = agbp->b_addr;
2521
2522 ASSERT(xfs_perag_agfl_needs_reset(pag));
2523 trace_xfs_agfl_reset(mp, agf, 0, _RET_IP_);
2524
2525 xfs_warn(mp,
2526 "WARNING: Reset corrupted AGFL on AG %u. %d blocks leaked. "
2527 "Please unmount and run xfs_repair.",
2528 pag->pag_agno, pag->pagf_flcount);
2529
2530 agf->agf_flfirst = 0;
2531 agf->agf_fllast = cpu_to_be32(xfs_agfl_size(mp) - 1);
2532 agf->agf_flcount = 0;
2533 xfs_alloc_log_agf(tp, agbp, XFS_AGF_FLFIRST | XFS_AGF_FLLAST |
2534 XFS_AGF_FLCOUNT);
2535
2536 pag->pagf_flcount = 0;
2537 clear_bit(XFS_AGSTATE_AGFL_NEEDS_RESET, &pag->pag_opstate);
2538}
2539
2540/*
2541 * Defer an AGFL block free. This is effectively equivalent to
2542 * xfs_free_extent_later() with some special handling particular to AGFL blocks.
2543 *
2544 * Deferring AGFL frees helps prevent log reservation overruns due to too many
2545 * allocation operations in a transaction. AGFL frees are prone to this problem
2546 * because for one they are always freed one at a time. Further, an immediate
2547 * AGFL block free can cause a btree join and require another block free before
2548 * the real allocation can proceed. Deferring the free disconnects freeing up
2549 * the AGFL slot from freeing the block.
2550 */
2551static int
2552xfs_defer_agfl_block(
2553 struct xfs_trans *tp,
2554 xfs_agnumber_t agno,
2555 xfs_agblock_t agbno,
2556 struct xfs_owner_info *oinfo)
2557{
2558 struct xfs_mount *mp = tp->t_mountp;
2559 struct xfs_extent_free_item *xefi;
2560 xfs_fsblock_t fsbno = XFS_AGB_TO_FSB(mp, agno, agbno);
2561
2562 ASSERT(xfs_extfree_item_cache != NULL);
2563 ASSERT(oinfo != NULL);
2564
2565 if (XFS_IS_CORRUPT(mp, !xfs_verify_fsbno(mp, fsbno)))
2566 return -EFSCORRUPTED;
2567
2568 xefi = kmem_cache_zalloc(xfs_extfree_item_cache,
2569 GFP_KERNEL | __GFP_NOFAIL);
2570 xefi->xefi_startblock = fsbno;
2571 xefi->xefi_blockcount = 1;
2572 xefi->xefi_owner = oinfo->oi_owner;
2573 xefi->xefi_agresv = XFS_AG_RESV_AGFL;
2574
2575 trace_xfs_agfl_free_defer(mp, agno, 0, agbno, 1);
2576
2577 xfs_extent_free_get_group(mp, xefi);
2578 xfs_defer_add(tp, &xefi->xefi_list, &xfs_agfl_free_defer_type);
2579 return 0;
2580}
2581
2582/*
2583 * Add the extent to the list of extents to be free at transaction end.
2584 * The list is maintained sorted (by block number).
2585 */
2586static int
2587xfs_defer_extent_free(
2588 struct xfs_trans *tp,
2589 xfs_fsblock_t bno,
2590 xfs_filblks_t len,
2591 const struct xfs_owner_info *oinfo,
2592 enum xfs_ag_resv_type type,
2593 bool skip_discard,
2594 struct xfs_defer_pending **dfpp)
2595{
2596 struct xfs_extent_free_item *xefi;
2597 struct xfs_mount *mp = tp->t_mountp;
2598#ifdef DEBUG
2599 xfs_agnumber_t agno;
2600 xfs_agblock_t agbno;
2601
2602 ASSERT(bno != NULLFSBLOCK);
2603 ASSERT(len > 0);
2604 ASSERT(len <= XFS_MAX_BMBT_EXTLEN);
2605 ASSERT(!isnullstartblock(bno));
2606 agno = XFS_FSB_TO_AGNO(mp, bno);
2607 agbno = XFS_FSB_TO_AGBNO(mp, bno);
2608 ASSERT(agno < mp->m_sb.sb_agcount);
2609 ASSERT(agbno < mp->m_sb.sb_agblocks);
2610 ASSERT(len < mp->m_sb.sb_agblocks);
2611 ASSERT(agbno + len <= mp->m_sb.sb_agblocks);
2612#endif
2613 ASSERT(xfs_extfree_item_cache != NULL);
2614 ASSERT(type != XFS_AG_RESV_AGFL);
2615
2616 if (XFS_IS_CORRUPT(mp, !xfs_verify_fsbext(mp, bno, len)))
2617 return -EFSCORRUPTED;
2618
2619 xefi = kmem_cache_zalloc(xfs_extfree_item_cache,
2620 GFP_KERNEL | __GFP_NOFAIL);
2621 xefi->xefi_startblock = bno;
2622 xefi->xefi_blockcount = (xfs_extlen_t)len;
2623 xefi->xefi_agresv = type;
2624 if (skip_discard)
2625 xefi->xefi_flags |= XFS_EFI_SKIP_DISCARD;
2626 if (oinfo) {
2627 ASSERT(oinfo->oi_offset == 0);
2628
2629 if (oinfo->oi_flags & XFS_OWNER_INFO_ATTR_FORK)
2630 xefi->xefi_flags |= XFS_EFI_ATTR_FORK;
2631 if (oinfo->oi_flags & XFS_OWNER_INFO_BMBT_BLOCK)
2632 xefi->xefi_flags |= XFS_EFI_BMBT_BLOCK;
2633 xefi->xefi_owner = oinfo->oi_owner;
2634 } else {
2635 xefi->xefi_owner = XFS_RMAP_OWN_NULL;
2636 }
2637 trace_xfs_bmap_free_defer(mp,
2638 XFS_FSB_TO_AGNO(tp->t_mountp, bno), 0,
2639 XFS_FSB_TO_AGBNO(tp->t_mountp, bno), len);
2640
2641 xfs_extent_free_get_group(mp, xefi);
2642 *dfpp = xfs_defer_add(tp, &xefi->xefi_list, &xfs_extent_free_defer_type);
2643 return 0;
2644}
2645
2646int
2647xfs_free_extent_later(
2648 struct xfs_trans *tp,
2649 xfs_fsblock_t bno,
2650 xfs_filblks_t len,
2651 const struct xfs_owner_info *oinfo,
2652 enum xfs_ag_resv_type type,
2653 bool skip_discard)
2654{
2655 struct xfs_defer_pending *dontcare = NULL;
2656
2657 return xfs_defer_extent_free(tp, bno, len, oinfo, type, skip_discard,
2658 &dontcare);
2659}
2660
2661/*
2662 * Set up automatic freeing of unwritten space in the filesystem.
2663 *
2664 * This function attached a paused deferred extent free item to the
2665 * transaction. Pausing means that the EFI will be logged in the next
2666 * transaction commit, but the pending EFI will not be finished until the
2667 * pending item is unpaused.
2668 *
2669 * If the system goes down after the EFI has been persisted to the log but
2670 * before the pending item is unpaused, log recovery will find the EFI, fail to
2671 * find the EFD, and free the space.
2672 *
2673 * If the pending item is unpaused, the next transaction commit will log an EFD
2674 * without freeing the space.
2675 *
2676 * Caller must ensure that the tp, fsbno, len, oinfo, and resv flags of the
2677 * @args structure are set to the relevant values.
2678 */
2679int
2680xfs_alloc_schedule_autoreap(
2681 const struct xfs_alloc_arg *args,
2682 bool skip_discard,
2683 struct xfs_alloc_autoreap *aarp)
2684{
2685 int error;
2686
2687 error = xfs_defer_extent_free(args->tp, args->fsbno, args->len,
2688 &args->oinfo, args->resv, skip_discard, &aarp->dfp);
2689 if (error)
2690 return error;
2691
2692 xfs_defer_item_pause(args->tp, aarp->dfp);
2693 return 0;
2694}
2695
2696/*
2697 * Cancel automatic freeing of unwritten space in the filesystem.
2698 *
2699 * Earlier, we created a paused deferred extent free item and attached it to
2700 * this transaction so that we could automatically roll back a new space
2701 * allocation if the system went down. Now we want to cancel the paused work
2702 * item by marking the EFI stale so we don't actually free the space, unpausing
2703 * the pending item and logging an EFD.
2704 *
2705 * The caller generally should have already mapped the space into the ondisk
2706 * filesystem. If the reserved space was partially used, the caller must call
2707 * xfs_free_extent_later to create a new EFI to free the unused space.
2708 */
2709void
2710xfs_alloc_cancel_autoreap(
2711 struct xfs_trans *tp,
2712 struct xfs_alloc_autoreap *aarp)
2713{
2714 struct xfs_defer_pending *dfp = aarp->dfp;
2715 struct xfs_extent_free_item *xefi;
2716
2717 if (!dfp)
2718 return;
2719
2720 list_for_each_entry(xefi, &dfp->dfp_work, xefi_list)
2721 xefi->xefi_flags |= XFS_EFI_CANCELLED;
2722
2723 xfs_defer_item_unpause(tp, dfp);
2724}
2725
2726/*
2727 * Commit automatic freeing of unwritten space in the filesystem.
2728 *
2729 * This unpauses an earlier _schedule_autoreap and commits to freeing the
2730 * allocated space. Call this if none of the reserved space was used.
2731 */
2732void
2733xfs_alloc_commit_autoreap(
2734 struct xfs_trans *tp,
2735 struct xfs_alloc_autoreap *aarp)
2736{
2737 if (aarp->dfp)
2738 xfs_defer_item_unpause(tp, aarp->dfp);
2739}
2740
2741#ifdef DEBUG
2742/*
2743 * Check if an AGF has a free extent record whose length is equal to
2744 * args->minlen.
2745 */
2746STATIC int
2747xfs_exact_minlen_extent_available(
2748 struct xfs_alloc_arg *args,
2749 struct xfs_buf *agbp,
2750 int *stat)
2751{
2752 struct xfs_btree_cur *cnt_cur;
2753 xfs_agblock_t fbno;
2754 xfs_extlen_t flen;
2755 int error = 0;
2756
2757 cnt_cur = xfs_cntbt_init_cursor(args->mp, args->tp, agbp,
2758 args->pag);
2759 error = xfs_alloc_lookup_ge(cnt_cur, 0, args->minlen, stat);
2760 if (error)
2761 goto out;
2762
2763 if (*stat == 0) {
2764 xfs_btree_mark_sick(cnt_cur);
2765 error = -EFSCORRUPTED;
2766 goto out;
2767 }
2768
2769 error = xfs_alloc_get_rec(cnt_cur, &fbno, &flen, stat);
2770 if (error)
2771 goto out;
2772
2773 if (*stat == 1 && flen != args->minlen)
2774 *stat = 0;
2775
2776out:
2777 xfs_btree_del_cursor(cnt_cur, error);
2778
2779 return error;
2780}
2781#endif
2782
2783/*
2784 * Decide whether to use this allocation group for this allocation.
2785 * If so, fix up the btree freelist's size.
2786 */
2787int /* error */
2788xfs_alloc_fix_freelist(
2789 struct xfs_alloc_arg *args, /* allocation argument structure */
2790 uint32_t alloc_flags)
2791{
2792 struct xfs_mount *mp = args->mp;
2793 struct xfs_perag *pag = args->pag;
2794 struct xfs_trans *tp = args->tp;
2795 struct xfs_buf *agbp = NULL;
2796 struct xfs_buf *agflbp = NULL;
2797 struct xfs_alloc_arg targs; /* local allocation arguments */
2798 xfs_agblock_t bno; /* freelist block */
2799 xfs_extlen_t need; /* total blocks needed in freelist */
2800 int error = 0;
2801
2802 /* deferred ops (AGFL block frees) require permanent transactions */
2803 ASSERT(tp->t_flags & XFS_TRANS_PERM_LOG_RES);
2804
2805 if (!xfs_perag_initialised_agf(pag)) {
2806 error = xfs_alloc_read_agf(pag, tp, alloc_flags, &agbp);
2807 if (error) {
2808 /* Couldn't lock the AGF so skip this AG. */
2809 if (error == -EAGAIN)
2810 error = 0;
2811 goto out_no_agbp;
2812 }
2813 }
2814
2815 /*
2816 * If this is a metadata preferred pag and we are user data then try
2817 * somewhere else if we are not being asked to try harder at this
2818 * point
2819 */
2820 if (xfs_perag_prefers_metadata(pag) &&
2821 (args->datatype & XFS_ALLOC_USERDATA) &&
2822 (alloc_flags & XFS_ALLOC_FLAG_TRYLOCK)) {
2823 ASSERT(!(alloc_flags & XFS_ALLOC_FLAG_FREEING));
2824 goto out_agbp_relse;
2825 }
2826
2827 need = xfs_alloc_min_freelist(mp, pag);
2828 if (!xfs_alloc_space_available(args, need, alloc_flags |
2829 XFS_ALLOC_FLAG_CHECK))
2830 goto out_agbp_relse;
2831
2832 /*
2833 * Get the a.g. freespace buffer.
2834 * Can fail if we're not blocking on locks, and it's held.
2835 */
2836 if (!agbp) {
2837 error = xfs_alloc_read_agf(pag, tp, alloc_flags, &agbp);
2838 if (error) {
2839 /* Couldn't lock the AGF so skip this AG. */
2840 if (error == -EAGAIN)
2841 error = 0;
2842 goto out_no_agbp;
2843 }
2844 }
2845
2846 /* reset a padding mismatched agfl before final free space check */
2847 if (xfs_perag_agfl_needs_reset(pag))
2848 xfs_agfl_reset(tp, agbp, pag);
2849
2850 /* If there isn't enough total space or single-extent, reject it. */
2851 need = xfs_alloc_min_freelist(mp, pag);
2852 if (!xfs_alloc_space_available(args, need, alloc_flags))
2853 goto out_agbp_relse;
2854
2855#ifdef DEBUG
2856 if (args->alloc_minlen_only) {
2857 int stat;
2858
2859 error = xfs_exact_minlen_extent_available(args, agbp, &stat);
2860 if (error || !stat)
2861 goto out_agbp_relse;
2862 }
2863#endif
2864 /*
2865 * Make the freelist shorter if it's too long.
2866 *
2867 * Note that from this point onwards, we will always release the agf and
2868 * agfl buffers on error. This handles the case where we error out and
2869 * the buffers are clean or may not have been joined to the transaction
2870 * and hence need to be released manually. If they have been joined to
2871 * the transaction, then xfs_trans_brelse() will handle them
2872 * appropriately based on the recursion count and dirty state of the
2873 * buffer.
2874 *
2875 * XXX (dgc): When we have lots of free space, does this buy us
2876 * anything other than extra overhead when we need to put more blocks
2877 * back on the free list? Maybe we should only do this when space is
2878 * getting low or the AGFL is more than half full?
2879 *
2880 * The NOSHRINK flag prevents the AGFL from being shrunk if it's too
2881 * big; the NORMAP flag prevents AGFL expand/shrink operations from
2882 * updating the rmapbt. Both flags are used in xfs_repair while we're
2883 * rebuilding the rmapbt, and neither are used by the kernel. They're
2884 * both required to ensure that rmaps are correctly recorded for the
2885 * regenerated AGFL, bnobt, and cntbt. See repair/phase5.c and
2886 * repair/rmap.c in xfsprogs for details.
2887 */
2888 memset(&targs, 0, sizeof(targs));
2889 /* struct copy below */
2890 if (alloc_flags & XFS_ALLOC_FLAG_NORMAP)
2891 targs.oinfo = XFS_RMAP_OINFO_SKIP_UPDATE;
2892 else
2893 targs.oinfo = XFS_RMAP_OINFO_AG;
2894 while (!(alloc_flags & XFS_ALLOC_FLAG_NOSHRINK) &&
2895 pag->pagf_flcount > need) {
2896 error = xfs_alloc_get_freelist(pag, tp, agbp, &bno, 0);
2897 if (error)
2898 goto out_agbp_relse;
2899
2900 /* defer agfl frees */
2901 error = xfs_defer_agfl_block(tp, args->agno, bno, &targs.oinfo);
2902 if (error)
2903 goto out_agbp_relse;
2904 }
2905
2906 targs.tp = tp;
2907 targs.mp = mp;
2908 targs.agbp = agbp;
2909 targs.agno = args->agno;
2910 targs.alignment = targs.minlen = targs.prod = 1;
2911 targs.pag = pag;
2912 error = xfs_alloc_read_agfl(pag, tp, &agflbp);
2913 if (error)
2914 goto out_agbp_relse;
2915
2916 /* Make the freelist longer if it's too short. */
2917 while (pag->pagf_flcount < need) {
2918 targs.agbno = 0;
2919 targs.maxlen = need - pag->pagf_flcount;
2920 targs.resv = XFS_AG_RESV_AGFL;
2921
2922 /* Allocate as many blocks as possible at once. */
2923 error = xfs_alloc_ag_vextent_size(&targs, alloc_flags);
2924 if (error)
2925 goto out_agflbp_relse;
2926
2927 /*
2928 * Stop if we run out. Won't happen if callers are obeying
2929 * the restrictions correctly. Can happen for free calls
2930 * on a completely full ag.
2931 */
2932 if (targs.agbno == NULLAGBLOCK) {
2933 if (alloc_flags & XFS_ALLOC_FLAG_FREEING)
2934 break;
2935 goto out_agflbp_relse;
2936 }
2937
2938 if (!xfs_rmap_should_skip_owner_update(&targs.oinfo)) {
2939 error = xfs_rmap_alloc(tp, agbp, pag,
2940 targs.agbno, targs.len, &targs.oinfo);
2941 if (error)
2942 goto out_agflbp_relse;
2943 }
2944 error = xfs_alloc_update_counters(tp, agbp,
2945 -((long)(targs.len)));
2946 if (error)
2947 goto out_agflbp_relse;
2948
2949 /*
2950 * Put each allocated block on the list.
2951 */
2952 for (bno = targs.agbno; bno < targs.agbno + targs.len; bno++) {
2953 error = xfs_alloc_put_freelist(pag, tp, agbp,
2954 agflbp, bno, 0);
2955 if (error)
2956 goto out_agflbp_relse;
2957 }
2958 }
2959 xfs_trans_brelse(tp, agflbp);
2960 args->agbp = agbp;
2961 return 0;
2962
2963out_agflbp_relse:
2964 xfs_trans_brelse(tp, agflbp);
2965out_agbp_relse:
2966 if (agbp)
2967 xfs_trans_brelse(tp, agbp);
2968out_no_agbp:
2969 args->agbp = NULL;
2970 return error;
2971}
2972
2973/*
2974 * Get a block from the freelist.
2975 * Returns with the buffer for the block gotten.
2976 */
2977int
2978xfs_alloc_get_freelist(
2979 struct xfs_perag *pag,
2980 struct xfs_trans *tp,
2981 struct xfs_buf *agbp,
2982 xfs_agblock_t *bnop,
2983 int btreeblk)
2984{
2985 struct xfs_agf *agf = agbp->b_addr;
2986 struct xfs_buf *agflbp;
2987 xfs_agblock_t bno;
2988 __be32 *agfl_bno;
2989 int error;
2990 uint32_t logflags;
2991 struct xfs_mount *mp = tp->t_mountp;
2992
2993 /*
2994 * Freelist is empty, give up.
2995 */
2996 if (!agf->agf_flcount) {
2997 *bnop = NULLAGBLOCK;
2998 return 0;
2999 }
3000 /*
3001 * Read the array of free blocks.
3002 */
3003 error = xfs_alloc_read_agfl(pag, tp, &agflbp);
3004 if (error)
3005 return error;
3006
3007
3008 /*
3009 * Get the block number and update the data structures.
3010 */
3011 agfl_bno = xfs_buf_to_agfl_bno(agflbp);
3012 bno = be32_to_cpu(agfl_bno[be32_to_cpu(agf->agf_flfirst)]);
3013 if (XFS_IS_CORRUPT(tp->t_mountp, !xfs_verify_agbno(pag, bno)))
3014 return -EFSCORRUPTED;
3015
3016 be32_add_cpu(&agf->agf_flfirst, 1);
3017 xfs_trans_brelse(tp, agflbp);
3018 if (be32_to_cpu(agf->agf_flfirst) == xfs_agfl_size(mp))
3019 agf->agf_flfirst = 0;
3020
3021 ASSERT(!xfs_perag_agfl_needs_reset(pag));
3022 be32_add_cpu(&agf->agf_flcount, -1);
3023 pag->pagf_flcount--;
3024
3025 logflags = XFS_AGF_FLFIRST | XFS_AGF_FLCOUNT;
3026 if (btreeblk) {
3027 be32_add_cpu(&agf->agf_btreeblks, 1);
3028 pag->pagf_btreeblks++;
3029 logflags |= XFS_AGF_BTREEBLKS;
3030 }
3031
3032 xfs_alloc_log_agf(tp, agbp, logflags);
3033 *bnop = bno;
3034
3035 return 0;
3036}
3037
3038/*
3039 * Log the given fields from the agf structure.
3040 */
3041void
3042xfs_alloc_log_agf(
3043 struct xfs_trans *tp,
3044 struct xfs_buf *bp,
3045 uint32_t fields)
3046{
3047 int first; /* first byte offset */
3048 int last; /* last byte offset */
3049 static const short offsets[] = {
3050 offsetof(xfs_agf_t, agf_magicnum),
3051 offsetof(xfs_agf_t, agf_versionnum),
3052 offsetof(xfs_agf_t, agf_seqno),
3053 offsetof(xfs_agf_t, agf_length),
3054 offsetof(xfs_agf_t, agf_bno_root), /* also cnt/rmap root */
3055 offsetof(xfs_agf_t, agf_bno_level), /* also cnt/rmap levels */
3056 offsetof(xfs_agf_t, agf_flfirst),
3057 offsetof(xfs_agf_t, agf_fllast),
3058 offsetof(xfs_agf_t, agf_flcount),
3059 offsetof(xfs_agf_t, agf_freeblks),
3060 offsetof(xfs_agf_t, agf_longest),
3061 offsetof(xfs_agf_t, agf_btreeblks),
3062 offsetof(xfs_agf_t, agf_uuid),
3063 offsetof(xfs_agf_t, agf_rmap_blocks),
3064 offsetof(xfs_agf_t, agf_refcount_blocks),
3065 offsetof(xfs_agf_t, agf_refcount_root),
3066 offsetof(xfs_agf_t, agf_refcount_level),
3067 /* needed so that we don't log the whole rest of the structure: */
3068 offsetof(xfs_agf_t, agf_spare64),
3069 sizeof(xfs_agf_t)
3070 };
3071
3072 trace_xfs_agf(tp->t_mountp, bp->b_addr, fields, _RET_IP_);
3073
3074 xfs_trans_buf_set_type(tp, bp, XFS_BLFT_AGF_BUF);
3075
3076 xfs_btree_offsets(fields, offsets, XFS_AGF_NUM_BITS, &first, &last);
3077 xfs_trans_log_buf(tp, bp, (uint)first, (uint)last);
3078}
3079
3080/*
3081 * Put the block on the freelist for the allocation group.
3082 */
3083int
3084xfs_alloc_put_freelist(
3085 struct xfs_perag *pag,
3086 struct xfs_trans *tp,
3087 struct xfs_buf *agbp,
3088 struct xfs_buf *agflbp,
3089 xfs_agblock_t bno,
3090 int btreeblk)
3091{
3092 struct xfs_mount *mp = tp->t_mountp;
3093 struct xfs_agf *agf = agbp->b_addr;
3094 __be32 *blockp;
3095 int error;
3096 uint32_t logflags;
3097 __be32 *agfl_bno;
3098 int startoff;
3099
3100 if (!agflbp) {
3101 error = xfs_alloc_read_agfl(pag, tp, &agflbp);
3102 if (error)
3103 return error;
3104 }
3105
3106 be32_add_cpu(&agf->agf_fllast, 1);
3107 if (be32_to_cpu(agf->agf_fllast) == xfs_agfl_size(mp))
3108 agf->agf_fllast = 0;
3109
3110 ASSERT(!xfs_perag_agfl_needs_reset(pag));
3111 be32_add_cpu(&agf->agf_flcount, 1);
3112 pag->pagf_flcount++;
3113
3114 logflags = XFS_AGF_FLLAST | XFS_AGF_FLCOUNT;
3115 if (btreeblk) {
3116 be32_add_cpu(&agf->agf_btreeblks, -1);
3117 pag->pagf_btreeblks--;
3118 logflags |= XFS_AGF_BTREEBLKS;
3119 }
3120
3121 xfs_alloc_log_agf(tp, agbp, logflags);
3122
3123 ASSERT(be32_to_cpu(agf->agf_flcount) <= xfs_agfl_size(mp));
3124
3125 agfl_bno = xfs_buf_to_agfl_bno(agflbp);
3126 blockp = &agfl_bno[be32_to_cpu(agf->agf_fllast)];
3127 *blockp = cpu_to_be32(bno);
3128 startoff = (char *)blockp - (char *)agflbp->b_addr;
3129
3130 xfs_alloc_log_agf(tp, agbp, logflags);
3131
3132 xfs_trans_buf_set_type(tp, agflbp, XFS_BLFT_AGFL_BUF);
3133 xfs_trans_log_buf(tp, agflbp, startoff,
3134 startoff + sizeof(xfs_agblock_t) - 1);
3135 return 0;
3136}
3137
3138/*
3139 * Check that this AGF/AGI header's sequence number and length matches the AG
3140 * number and size in fsblocks.
3141 */
3142xfs_failaddr_t
3143xfs_validate_ag_length(
3144 struct xfs_buf *bp,
3145 uint32_t seqno,
3146 uint32_t length)
3147{
3148 struct xfs_mount *mp = bp->b_mount;
3149 /*
3150 * During growfs operations, the perag is not fully initialised,
3151 * so we can't use it for any useful checking. growfs ensures we can't
3152 * use it by using uncached buffers that don't have the perag attached
3153 * so we can detect and avoid this problem.
3154 */
3155 if (bp->b_pag && seqno != bp->b_pag->pag_agno)
3156 return __this_address;
3157
3158 /*
3159 * Only the last AG in the filesystem is allowed to be shorter
3160 * than the AG size recorded in the superblock.
3161 */
3162 if (length != mp->m_sb.sb_agblocks) {
3163 /*
3164 * During growfs, the new last AG can get here before we
3165 * have updated the superblock. Give it a pass on the seqno
3166 * check.
3167 */
3168 if (bp->b_pag && seqno != mp->m_sb.sb_agcount - 1)
3169 return __this_address;
3170 if (length < XFS_MIN_AG_BLOCKS)
3171 return __this_address;
3172 if (length > mp->m_sb.sb_agblocks)
3173 return __this_address;
3174 }
3175
3176 return NULL;
3177}
3178
3179/*
3180 * Verify the AGF is consistent.
3181 *
3182 * We do not verify the AGFL indexes in the AGF are fully consistent here
3183 * because of issues with variable on-disk structure sizes. Instead, we check
3184 * the agfl indexes for consistency when we initialise the perag from the AGF
3185 * information after a read completes.
3186 *
3187 * If the index is inconsistent, then we mark the perag as needing an AGFL
3188 * reset. The first AGFL update performed then resets the AGFL indexes and
3189 * refills the AGFL with known good free blocks, allowing the filesystem to
3190 * continue operating normally at the cost of a few leaked free space blocks.
3191 */
3192static xfs_failaddr_t
3193xfs_agf_verify(
3194 struct xfs_buf *bp)
3195{
3196 struct xfs_mount *mp = bp->b_mount;
3197 struct xfs_agf *agf = bp->b_addr;
3198 xfs_failaddr_t fa;
3199 uint32_t agf_seqno = be32_to_cpu(agf->agf_seqno);
3200 uint32_t agf_length = be32_to_cpu(agf->agf_length);
3201
3202 if (xfs_has_crc(mp)) {
3203 if (!uuid_equal(&agf->agf_uuid, &mp->m_sb.sb_meta_uuid))
3204 return __this_address;
3205 if (!xfs_log_check_lsn(mp, be64_to_cpu(agf->agf_lsn)))
3206 return __this_address;
3207 }
3208
3209 if (!xfs_verify_magic(bp, agf->agf_magicnum))
3210 return __this_address;
3211
3212 if (!XFS_AGF_GOOD_VERSION(be32_to_cpu(agf->agf_versionnum)))
3213 return __this_address;
3214
3215 /*
3216 * Both agf_seqno and agf_length need to validated before anything else
3217 * block number related in the AGF or AGFL can be checked.
3218 */
3219 fa = xfs_validate_ag_length(bp, agf_seqno, agf_length);
3220 if (fa)
3221 return fa;
3222
3223 if (be32_to_cpu(agf->agf_flfirst) >= xfs_agfl_size(mp))
3224 return __this_address;
3225 if (be32_to_cpu(agf->agf_fllast) >= xfs_agfl_size(mp))
3226 return __this_address;
3227 if (be32_to_cpu(agf->agf_flcount) > xfs_agfl_size(mp))
3228 return __this_address;
3229
3230 if (be32_to_cpu(agf->agf_freeblks) < be32_to_cpu(agf->agf_longest) ||
3231 be32_to_cpu(agf->agf_freeblks) > agf_length)
3232 return __this_address;
3233
3234 if (be32_to_cpu(agf->agf_bno_level) < 1 ||
3235 be32_to_cpu(agf->agf_cnt_level) < 1 ||
3236 be32_to_cpu(agf->agf_bno_level) > mp->m_alloc_maxlevels ||
3237 be32_to_cpu(agf->agf_cnt_level) > mp->m_alloc_maxlevels)
3238 return __this_address;
3239
3240 if (xfs_has_lazysbcount(mp) &&
3241 be32_to_cpu(agf->agf_btreeblks) > agf_length)
3242 return __this_address;
3243
3244 if (xfs_has_rmapbt(mp)) {
3245 if (be32_to_cpu(agf->agf_rmap_blocks) > agf_length)
3246 return __this_address;
3247
3248 if (be32_to_cpu(agf->agf_rmap_level) < 1 ||
3249 be32_to_cpu(agf->agf_rmap_level) > mp->m_rmap_maxlevels)
3250 return __this_address;
3251 }
3252
3253 if (xfs_has_reflink(mp)) {
3254 if (be32_to_cpu(agf->agf_refcount_blocks) > agf_length)
3255 return __this_address;
3256
3257 if (be32_to_cpu(agf->agf_refcount_level) < 1 ||
3258 be32_to_cpu(agf->agf_refcount_level) > mp->m_refc_maxlevels)
3259 return __this_address;
3260 }
3261
3262 return NULL;
3263}
3264
3265static void
3266xfs_agf_read_verify(
3267 struct xfs_buf *bp)
3268{
3269 struct xfs_mount *mp = bp->b_mount;
3270 xfs_failaddr_t fa;
3271
3272 if (xfs_has_crc(mp) &&
3273 !xfs_buf_verify_cksum(bp, XFS_AGF_CRC_OFF))
3274 xfs_verifier_error(bp, -EFSBADCRC, __this_address);
3275 else {
3276 fa = xfs_agf_verify(bp);
3277 if (XFS_TEST_ERROR(fa, mp, XFS_ERRTAG_ALLOC_READ_AGF))
3278 xfs_verifier_error(bp, -EFSCORRUPTED, fa);
3279 }
3280}
3281
3282static void
3283xfs_agf_write_verify(
3284 struct xfs_buf *bp)
3285{
3286 struct xfs_mount *mp = bp->b_mount;
3287 struct xfs_buf_log_item *bip = bp->b_log_item;
3288 struct xfs_agf *agf = bp->b_addr;
3289 xfs_failaddr_t fa;
3290
3291 fa = xfs_agf_verify(bp);
3292 if (fa) {
3293 xfs_verifier_error(bp, -EFSCORRUPTED, fa);
3294 return;
3295 }
3296
3297 if (!xfs_has_crc(mp))
3298 return;
3299
3300 if (bip)
3301 agf->agf_lsn = cpu_to_be64(bip->bli_item.li_lsn);
3302
3303 xfs_buf_update_cksum(bp, XFS_AGF_CRC_OFF);
3304}
3305
3306const struct xfs_buf_ops xfs_agf_buf_ops = {
3307 .name = "xfs_agf",
3308 .magic = { cpu_to_be32(XFS_AGF_MAGIC), cpu_to_be32(XFS_AGF_MAGIC) },
3309 .verify_read = xfs_agf_read_verify,
3310 .verify_write = xfs_agf_write_verify,
3311 .verify_struct = xfs_agf_verify,
3312};
3313
3314/*
3315 * Read in the allocation group header (free/alloc section).
3316 */
3317int
3318xfs_read_agf(
3319 struct xfs_perag *pag,
3320 struct xfs_trans *tp,
3321 int flags,
3322 struct xfs_buf **agfbpp)
3323{
3324 struct xfs_mount *mp = pag->pag_mount;
3325 int error;
3326
3327 trace_xfs_read_agf(pag->pag_mount, pag->pag_agno);
3328
3329 error = xfs_trans_read_buf(mp, tp, mp->m_ddev_targp,
3330 XFS_AG_DADDR(mp, pag->pag_agno, XFS_AGF_DADDR(mp)),
3331 XFS_FSS_TO_BB(mp, 1), flags, agfbpp, &xfs_agf_buf_ops);
3332 if (xfs_metadata_is_sick(error))
3333 xfs_ag_mark_sick(pag, XFS_SICK_AG_AGF);
3334 if (error)
3335 return error;
3336
3337 xfs_buf_set_ref(*agfbpp, XFS_AGF_REF);
3338 return 0;
3339}
3340
3341/*
3342 * Read in the allocation group header (free/alloc section) and initialise the
3343 * perag structure if necessary. If the caller provides @agfbpp, then return the
3344 * locked buffer to the caller, otherwise free it.
3345 */
3346int
3347xfs_alloc_read_agf(
3348 struct xfs_perag *pag,
3349 struct xfs_trans *tp,
3350 int flags,
3351 struct xfs_buf **agfbpp)
3352{
3353 struct xfs_buf *agfbp;
3354 struct xfs_agf *agf;
3355 int error;
3356 int allocbt_blks;
3357
3358 trace_xfs_alloc_read_agf(pag->pag_mount, pag->pag_agno);
3359
3360 /* We don't support trylock when freeing. */
3361 ASSERT((flags & (XFS_ALLOC_FLAG_FREEING | XFS_ALLOC_FLAG_TRYLOCK)) !=
3362 (XFS_ALLOC_FLAG_FREEING | XFS_ALLOC_FLAG_TRYLOCK));
3363 error = xfs_read_agf(pag, tp,
3364 (flags & XFS_ALLOC_FLAG_TRYLOCK) ? XBF_TRYLOCK : 0,
3365 &agfbp);
3366 if (error)
3367 return error;
3368
3369 agf = agfbp->b_addr;
3370 if (!xfs_perag_initialised_agf(pag)) {
3371 pag->pagf_freeblks = be32_to_cpu(agf->agf_freeblks);
3372 pag->pagf_btreeblks = be32_to_cpu(agf->agf_btreeblks);
3373 pag->pagf_flcount = be32_to_cpu(agf->agf_flcount);
3374 pag->pagf_longest = be32_to_cpu(agf->agf_longest);
3375 pag->pagf_bno_level = be32_to_cpu(agf->agf_bno_level);
3376 pag->pagf_cnt_level = be32_to_cpu(agf->agf_cnt_level);
3377 pag->pagf_rmap_level = be32_to_cpu(agf->agf_rmap_level);
3378 pag->pagf_refcount_level = be32_to_cpu(agf->agf_refcount_level);
3379 if (xfs_agfl_needs_reset(pag->pag_mount, agf))
3380 set_bit(XFS_AGSTATE_AGFL_NEEDS_RESET, &pag->pag_opstate);
3381 else
3382 clear_bit(XFS_AGSTATE_AGFL_NEEDS_RESET, &pag->pag_opstate);
3383
3384 /*
3385 * Update the in-core allocbt counter. Filter out the rmapbt
3386 * subset of the btreeblks counter because the rmapbt is managed
3387 * by perag reservation. Subtract one for the rmapbt root block
3388 * because the rmap counter includes it while the btreeblks
3389 * counter only tracks non-root blocks.
3390 */
3391 allocbt_blks = pag->pagf_btreeblks;
3392 if (xfs_has_rmapbt(pag->pag_mount))
3393 allocbt_blks -= be32_to_cpu(agf->agf_rmap_blocks) - 1;
3394 if (allocbt_blks > 0)
3395 atomic64_add(allocbt_blks,
3396 &pag->pag_mount->m_allocbt_blks);
3397
3398 set_bit(XFS_AGSTATE_AGF_INIT, &pag->pag_opstate);
3399 }
3400#ifdef DEBUG
3401 else if (!xfs_is_shutdown(pag->pag_mount)) {
3402 ASSERT(pag->pagf_freeblks == be32_to_cpu(agf->agf_freeblks));
3403 ASSERT(pag->pagf_btreeblks == be32_to_cpu(agf->agf_btreeblks));
3404 ASSERT(pag->pagf_flcount == be32_to_cpu(agf->agf_flcount));
3405 ASSERT(pag->pagf_longest == be32_to_cpu(agf->agf_longest));
3406 ASSERT(pag->pagf_bno_level == be32_to_cpu(agf->agf_bno_level));
3407 ASSERT(pag->pagf_cnt_level == be32_to_cpu(agf->agf_cnt_level));
3408 }
3409#endif
3410 if (agfbpp)
3411 *agfbpp = agfbp;
3412 else
3413 xfs_trans_brelse(tp, agfbp);
3414 return 0;
3415}
3416
3417/*
3418 * Pre-proces allocation arguments to set initial state that we don't require
3419 * callers to set up correctly, as well as bounds check the allocation args
3420 * that are set up.
3421 */
3422static int
3423xfs_alloc_vextent_check_args(
3424 struct xfs_alloc_arg *args,
3425 xfs_fsblock_t target,
3426 xfs_agnumber_t *minimum_agno)
3427{
3428 struct xfs_mount *mp = args->mp;
3429 xfs_agblock_t agsize;
3430
3431 args->fsbno = NULLFSBLOCK;
3432
3433 *minimum_agno = 0;
3434 if (args->tp->t_highest_agno != NULLAGNUMBER)
3435 *minimum_agno = args->tp->t_highest_agno;
3436
3437 /*
3438 * Just fix this up, for the case where the last a.g. is shorter
3439 * (or there's only one a.g.) and the caller couldn't easily figure
3440 * that out (xfs_bmap_alloc).
3441 */
3442 agsize = mp->m_sb.sb_agblocks;
3443 if (args->maxlen > agsize)
3444 args->maxlen = agsize;
3445 if (args->alignment == 0)
3446 args->alignment = 1;
3447
3448 ASSERT(args->minlen > 0);
3449 ASSERT(args->maxlen > 0);
3450 ASSERT(args->alignment > 0);
3451 ASSERT(args->resv != XFS_AG_RESV_AGFL);
3452
3453 ASSERT(XFS_FSB_TO_AGNO(mp, target) < mp->m_sb.sb_agcount);
3454 ASSERT(XFS_FSB_TO_AGBNO(mp, target) < agsize);
3455 ASSERT(args->minlen <= args->maxlen);
3456 ASSERT(args->minlen <= agsize);
3457 ASSERT(args->mod < args->prod);
3458
3459 if (XFS_FSB_TO_AGNO(mp, target) >= mp->m_sb.sb_agcount ||
3460 XFS_FSB_TO_AGBNO(mp, target) >= agsize ||
3461 args->minlen > args->maxlen || args->minlen > agsize ||
3462 args->mod >= args->prod) {
3463 trace_xfs_alloc_vextent_badargs(args);
3464 return -ENOSPC;
3465 }
3466
3467 if (args->agno != NULLAGNUMBER && *minimum_agno > args->agno) {
3468 trace_xfs_alloc_vextent_skip_deadlock(args);
3469 return -ENOSPC;
3470 }
3471 return 0;
3472
3473}
3474
3475/*
3476 * Prepare an AG for allocation. If the AG is not prepared to accept the
3477 * allocation, return failure.
3478 *
3479 * XXX(dgc): The complexity of "need_pag" will go away as all caller paths are
3480 * modified to hold their own perag references.
3481 */
3482static int
3483xfs_alloc_vextent_prepare_ag(
3484 struct xfs_alloc_arg *args,
3485 uint32_t alloc_flags)
3486{
3487 bool need_pag = !args->pag;
3488 int error;
3489
3490 if (need_pag)
3491 args->pag = xfs_perag_get(args->mp, args->agno);
3492
3493 args->agbp = NULL;
3494 error = xfs_alloc_fix_freelist(args, alloc_flags);
3495 if (error) {
3496 trace_xfs_alloc_vextent_nofix(args);
3497 if (need_pag)
3498 xfs_perag_put(args->pag);
3499 args->agbno = NULLAGBLOCK;
3500 return error;
3501 }
3502 if (!args->agbp) {
3503 /* cannot allocate in this AG at all */
3504 trace_xfs_alloc_vextent_noagbp(args);
3505 args->agbno = NULLAGBLOCK;
3506 return 0;
3507 }
3508 args->wasfromfl = 0;
3509 return 0;
3510}
3511
3512/*
3513 * Post-process allocation results to account for the allocation if it succeed
3514 * and set the allocated block number correctly for the caller.
3515 *
3516 * XXX: we should really be returning ENOSPC for ENOSPC, not
3517 * hiding it behind a "successful" NULLFSBLOCK allocation.
3518 */
3519static int
3520xfs_alloc_vextent_finish(
3521 struct xfs_alloc_arg *args,
3522 xfs_agnumber_t minimum_agno,
3523 int alloc_error,
3524 bool drop_perag)
3525{
3526 struct xfs_mount *mp = args->mp;
3527 int error = 0;
3528
3529 /*
3530 * We can end up here with a locked AGF. If we failed, the caller is
3531 * likely going to try to allocate again with different parameters, and
3532 * that can widen the AGs that are searched for free space. If we have
3533 * to do BMBT block allocation, we have to do a new allocation.
3534 *
3535 * Hence leaving this function with the AGF locked opens up potential
3536 * ABBA AGF deadlocks because a future allocation attempt in this
3537 * transaction may attempt to lock a lower number AGF.
3538 *
3539 * We can't release the AGF until the transaction is commited, so at
3540 * this point we must update the "first allocation" tracker to point at
3541 * this AG if the tracker is empty or points to a lower AG. This allows
3542 * the next allocation attempt to be modified appropriately to avoid
3543 * deadlocks.
3544 */
3545 if (args->agbp &&
3546 (args->tp->t_highest_agno == NULLAGNUMBER ||
3547 args->agno > minimum_agno))
3548 args->tp->t_highest_agno = args->agno;
3549
3550 /*
3551 * If the allocation failed with an error or we had an ENOSPC result,
3552 * preserve the returned error whilst also marking the allocation result
3553 * as "no extent allocated". This ensures that callers that fail to
3554 * capture the error will still treat it as a failed allocation.
3555 */
3556 if (alloc_error || args->agbno == NULLAGBLOCK) {
3557 args->fsbno = NULLFSBLOCK;
3558 error = alloc_error;
3559 goto out_drop_perag;
3560 }
3561
3562 args->fsbno = XFS_AGB_TO_FSB(mp, args->agno, args->agbno);
3563
3564 ASSERT(args->len >= args->minlen);
3565 ASSERT(args->len <= args->maxlen);
3566 ASSERT(args->agbno % args->alignment == 0);
3567 XFS_AG_CHECK_DADDR(mp, XFS_FSB_TO_DADDR(mp, args->fsbno), args->len);
3568
3569 /* if not file data, insert new block into the reverse map btree */
3570 if (!xfs_rmap_should_skip_owner_update(&args->oinfo)) {
3571 error = xfs_rmap_alloc(args->tp, args->agbp, args->pag,
3572 args->agbno, args->len, &args->oinfo);
3573 if (error)
3574 goto out_drop_perag;
3575 }
3576
3577 if (!args->wasfromfl) {
3578 error = xfs_alloc_update_counters(args->tp, args->agbp,
3579 -((long)(args->len)));
3580 if (error)
3581 goto out_drop_perag;
3582
3583 ASSERT(!xfs_extent_busy_search(mp, args->pag, args->agbno,
3584 args->len));
3585 }
3586
3587 xfs_ag_resv_alloc_extent(args->pag, args->resv, args);
3588
3589 XFS_STATS_INC(mp, xs_allocx);
3590 XFS_STATS_ADD(mp, xs_allocb, args->len);
3591
3592 trace_xfs_alloc_vextent_finish(args);
3593
3594out_drop_perag:
3595 if (drop_perag && args->pag) {
3596 xfs_perag_rele(args->pag);
3597 args->pag = NULL;
3598 }
3599 return error;
3600}
3601
3602/*
3603 * Allocate within a single AG only. This uses a best-fit length algorithm so if
3604 * you need an exact sized allocation without locality constraints, this is the
3605 * fastest way to do it.
3606 *
3607 * Caller is expected to hold a perag reference in args->pag.
3608 */
3609int
3610xfs_alloc_vextent_this_ag(
3611 struct xfs_alloc_arg *args,
3612 xfs_agnumber_t agno)
3613{
3614 struct xfs_mount *mp = args->mp;
3615 xfs_agnumber_t minimum_agno;
3616 uint32_t alloc_flags = 0;
3617 int error;
3618
3619 ASSERT(args->pag != NULL);
3620 ASSERT(args->pag->pag_agno == agno);
3621
3622 args->agno = agno;
3623 args->agbno = 0;
3624
3625 trace_xfs_alloc_vextent_this_ag(args);
3626
3627 error = xfs_alloc_vextent_check_args(args, XFS_AGB_TO_FSB(mp, agno, 0),
3628 &minimum_agno);
3629 if (error) {
3630 if (error == -ENOSPC)
3631 return 0;
3632 return error;
3633 }
3634
3635 error = xfs_alloc_vextent_prepare_ag(args, alloc_flags);
3636 if (!error && args->agbp)
3637 error = xfs_alloc_ag_vextent_size(args, alloc_flags);
3638
3639 return xfs_alloc_vextent_finish(args, minimum_agno, error, false);
3640}
3641
3642/*
3643 * Iterate all AGs trying to allocate an extent starting from @start_ag.
3644 *
3645 * If the incoming allocation type is XFS_ALLOCTYPE_NEAR_BNO, it means the
3646 * allocation attempts in @start_agno have locality information. If we fail to
3647 * allocate in that AG, then we revert to anywhere-in-AG for all the other AGs
3648 * we attempt to allocation in as there is no locality optimisation possible for
3649 * those allocations.
3650 *
3651 * On return, args->pag may be left referenced if we finish before the "all
3652 * failed" return point. The allocation finish still needs the perag, and
3653 * so the caller will release it once they've finished the allocation.
3654 *
3655 * When we wrap the AG iteration at the end of the filesystem, we have to be
3656 * careful not to wrap into AGs below ones we already have locked in the
3657 * transaction if we are doing a blocking iteration. This will result in an
3658 * out-of-order locking of AGFs and hence can cause deadlocks.
3659 */
3660static int
3661xfs_alloc_vextent_iterate_ags(
3662 struct xfs_alloc_arg *args,
3663 xfs_agnumber_t minimum_agno,
3664 xfs_agnumber_t start_agno,
3665 xfs_agblock_t target_agbno,
3666 uint32_t alloc_flags)
3667{
3668 struct xfs_mount *mp = args->mp;
3669 xfs_agnumber_t restart_agno = minimum_agno;
3670 xfs_agnumber_t agno;
3671 int error = 0;
3672
3673 if (alloc_flags & XFS_ALLOC_FLAG_TRYLOCK)
3674 restart_agno = 0;
3675restart:
3676 for_each_perag_wrap_range(mp, start_agno, restart_agno,
3677 mp->m_sb.sb_agcount, agno, args->pag) {
3678 args->agno = agno;
3679 error = xfs_alloc_vextent_prepare_ag(args, alloc_flags);
3680 if (error)
3681 break;
3682 if (!args->agbp) {
3683 trace_xfs_alloc_vextent_loopfailed(args);
3684 continue;
3685 }
3686
3687 /*
3688 * Allocation is supposed to succeed now, so break out of the
3689 * loop regardless of whether we succeed or not.
3690 */
3691 if (args->agno == start_agno && target_agbno) {
3692 args->agbno = target_agbno;
3693 error = xfs_alloc_ag_vextent_near(args, alloc_flags);
3694 } else {
3695 args->agbno = 0;
3696 error = xfs_alloc_ag_vextent_size(args, alloc_flags);
3697 }
3698 break;
3699 }
3700 if (error) {
3701 xfs_perag_rele(args->pag);
3702 args->pag = NULL;
3703 return error;
3704 }
3705 if (args->agbp)
3706 return 0;
3707
3708 /*
3709 * We didn't find an AG we can alloation from. If we were given
3710 * constraining flags by the caller, drop them and retry the allocation
3711 * without any constraints being set.
3712 */
3713 if (alloc_flags & XFS_ALLOC_FLAG_TRYLOCK) {
3714 alloc_flags &= ~XFS_ALLOC_FLAG_TRYLOCK;
3715 restart_agno = minimum_agno;
3716 goto restart;
3717 }
3718
3719 ASSERT(args->pag == NULL);
3720 trace_xfs_alloc_vextent_allfailed(args);
3721 return 0;
3722}
3723
3724/*
3725 * Iterate from the AGs from the start AG to the end of the filesystem, trying
3726 * to allocate blocks. It starts with a near allocation attempt in the initial
3727 * AG, then falls back to anywhere-in-ag after the first AG fails. It will wrap
3728 * back to zero if allowed by previous allocations in this transaction,
3729 * otherwise will wrap back to the start AG and run a second blocking pass to
3730 * the end of the filesystem.
3731 */
3732int
3733xfs_alloc_vextent_start_ag(
3734 struct xfs_alloc_arg *args,
3735 xfs_fsblock_t target)
3736{
3737 struct xfs_mount *mp = args->mp;
3738 xfs_agnumber_t minimum_agno;
3739 xfs_agnumber_t start_agno;
3740 xfs_agnumber_t rotorstep = xfs_rotorstep;
3741 bool bump_rotor = false;
3742 uint32_t alloc_flags = XFS_ALLOC_FLAG_TRYLOCK;
3743 int error;
3744
3745 ASSERT(args->pag == NULL);
3746
3747 args->agno = NULLAGNUMBER;
3748 args->agbno = NULLAGBLOCK;
3749
3750 trace_xfs_alloc_vextent_start_ag(args);
3751
3752 error = xfs_alloc_vextent_check_args(args, target, &minimum_agno);
3753 if (error) {
3754 if (error == -ENOSPC)
3755 return 0;
3756 return error;
3757 }
3758
3759 if ((args->datatype & XFS_ALLOC_INITIAL_USER_DATA) &&
3760 xfs_is_inode32(mp)) {
3761 target = XFS_AGB_TO_FSB(mp,
3762 ((mp->m_agfrotor / rotorstep) %
3763 mp->m_sb.sb_agcount), 0);
3764 bump_rotor = 1;
3765 }
3766
3767 start_agno = max(minimum_agno, XFS_FSB_TO_AGNO(mp, target));
3768 error = xfs_alloc_vextent_iterate_ags(args, minimum_agno, start_agno,
3769 XFS_FSB_TO_AGBNO(mp, target), alloc_flags);
3770
3771 if (bump_rotor) {
3772 if (args->agno == start_agno)
3773 mp->m_agfrotor = (mp->m_agfrotor + 1) %
3774 (mp->m_sb.sb_agcount * rotorstep);
3775 else
3776 mp->m_agfrotor = (args->agno * rotorstep + 1) %
3777 (mp->m_sb.sb_agcount * rotorstep);
3778 }
3779
3780 return xfs_alloc_vextent_finish(args, minimum_agno, error, true);
3781}
3782
3783/*
3784 * Iterate from the agno indicated via @target through to the end of the
3785 * filesystem attempting blocking allocation. This does not wrap or try a second
3786 * pass, so will not recurse into AGs lower than indicated by the target.
3787 */
3788int
3789xfs_alloc_vextent_first_ag(
3790 struct xfs_alloc_arg *args,
3791 xfs_fsblock_t target)
3792 {
3793 struct xfs_mount *mp = args->mp;
3794 xfs_agnumber_t minimum_agno;
3795 xfs_agnumber_t start_agno;
3796 uint32_t alloc_flags = XFS_ALLOC_FLAG_TRYLOCK;
3797 int error;
3798
3799 ASSERT(args->pag == NULL);
3800
3801 args->agno = NULLAGNUMBER;
3802 args->agbno = NULLAGBLOCK;
3803
3804 trace_xfs_alloc_vextent_first_ag(args);
3805
3806 error = xfs_alloc_vextent_check_args(args, target, &minimum_agno);
3807 if (error) {
3808 if (error == -ENOSPC)
3809 return 0;
3810 return error;
3811 }
3812
3813 start_agno = max(minimum_agno, XFS_FSB_TO_AGNO(mp, target));
3814 error = xfs_alloc_vextent_iterate_ags(args, minimum_agno, start_agno,
3815 XFS_FSB_TO_AGBNO(mp, target), alloc_flags);
3816 return xfs_alloc_vextent_finish(args, minimum_agno, error, true);
3817}
3818
3819/*
3820 * Allocate at the exact block target or fail. Caller is expected to hold a
3821 * perag reference in args->pag.
3822 */
3823int
3824xfs_alloc_vextent_exact_bno(
3825 struct xfs_alloc_arg *args,
3826 xfs_fsblock_t target)
3827{
3828 struct xfs_mount *mp = args->mp;
3829 xfs_agnumber_t minimum_agno;
3830 int error;
3831
3832 ASSERT(args->pag != NULL);
3833 ASSERT(args->pag->pag_agno == XFS_FSB_TO_AGNO(mp, target));
3834
3835 args->agno = XFS_FSB_TO_AGNO(mp, target);
3836 args->agbno = XFS_FSB_TO_AGBNO(mp, target);
3837
3838 trace_xfs_alloc_vextent_exact_bno(args);
3839
3840 error = xfs_alloc_vextent_check_args(args, target, &minimum_agno);
3841 if (error) {
3842 if (error == -ENOSPC)
3843 return 0;
3844 return error;
3845 }
3846
3847 error = xfs_alloc_vextent_prepare_ag(args, 0);
3848 if (!error && args->agbp)
3849 error = xfs_alloc_ag_vextent_exact(args);
3850
3851 return xfs_alloc_vextent_finish(args, minimum_agno, error, false);
3852}
3853
3854/*
3855 * Allocate an extent as close to the target as possible. If there are not
3856 * viable candidates in the AG, then fail the allocation.
3857 *
3858 * Caller may or may not have a per-ag reference in args->pag.
3859 */
3860int
3861xfs_alloc_vextent_near_bno(
3862 struct xfs_alloc_arg *args,
3863 xfs_fsblock_t target)
3864{
3865 struct xfs_mount *mp = args->mp;
3866 xfs_agnumber_t minimum_agno;
3867 bool needs_perag = args->pag == NULL;
3868 uint32_t alloc_flags = 0;
3869 int error;
3870
3871 if (!needs_perag)
3872 ASSERT(args->pag->pag_agno == XFS_FSB_TO_AGNO(mp, target));
3873
3874 args->agno = XFS_FSB_TO_AGNO(mp, target);
3875 args->agbno = XFS_FSB_TO_AGBNO(mp, target);
3876
3877 trace_xfs_alloc_vextent_near_bno(args);
3878
3879 error = xfs_alloc_vextent_check_args(args, target, &minimum_agno);
3880 if (error) {
3881 if (error == -ENOSPC)
3882 return 0;
3883 return error;
3884 }
3885
3886 if (needs_perag)
3887 args->pag = xfs_perag_grab(mp, args->agno);
3888
3889 error = xfs_alloc_vextent_prepare_ag(args, alloc_flags);
3890 if (!error && args->agbp)
3891 error = xfs_alloc_ag_vextent_near(args, alloc_flags);
3892
3893 return xfs_alloc_vextent_finish(args, minimum_agno, error, needs_perag);
3894}
3895
3896/* Ensure that the freelist is at full capacity. */
3897int
3898xfs_free_extent_fix_freelist(
3899 struct xfs_trans *tp,
3900 struct xfs_perag *pag,
3901 struct xfs_buf **agbp)
3902{
3903 struct xfs_alloc_arg args;
3904 int error;
3905
3906 memset(&args, 0, sizeof(struct xfs_alloc_arg));
3907 args.tp = tp;
3908 args.mp = tp->t_mountp;
3909 args.agno = pag->pag_agno;
3910 args.pag = pag;
3911
3912 /*
3913 * validate that the block number is legal - the enables us to detect
3914 * and handle a silent filesystem corruption rather than crashing.
3915 */
3916 if (args.agno >= args.mp->m_sb.sb_agcount)
3917 return -EFSCORRUPTED;
3918
3919 error = xfs_alloc_fix_freelist(&args, XFS_ALLOC_FLAG_FREEING);
3920 if (error)
3921 return error;
3922
3923 *agbp = args.agbp;
3924 return 0;
3925}
3926
3927/*
3928 * Free an extent.
3929 * Just break up the extent address and hand off to xfs_free_ag_extent
3930 * after fixing up the freelist.
3931 */
3932int
3933__xfs_free_extent(
3934 struct xfs_trans *tp,
3935 struct xfs_perag *pag,
3936 xfs_agblock_t agbno,
3937 xfs_extlen_t len,
3938 const struct xfs_owner_info *oinfo,
3939 enum xfs_ag_resv_type type,
3940 bool skip_discard)
3941{
3942 struct xfs_mount *mp = tp->t_mountp;
3943 struct xfs_buf *agbp;
3944 struct xfs_agf *agf;
3945 int error;
3946 unsigned int busy_flags = 0;
3947
3948 ASSERT(len != 0);
3949 ASSERT(type != XFS_AG_RESV_AGFL);
3950
3951 if (XFS_TEST_ERROR(false, mp,
3952 XFS_ERRTAG_FREE_EXTENT))
3953 return -EIO;
3954
3955 error = xfs_free_extent_fix_freelist(tp, pag, &agbp);
3956 if (error) {
3957 if (xfs_metadata_is_sick(error))
3958 xfs_ag_mark_sick(pag, XFS_SICK_AG_BNOBT);
3959 return error;
3960 }
3961
3962 agf = agbp->b_addr;
3963
3964 if (XFS_IS_CORRUPT(mp, agbno >= mp->m_sb.sb_agblocks)) {
3965 xfs_ag_mark_sick(pag, XFS_SICK_AG_BNOBT);
3966 error = -EFSCORRUPTED;
3967 goto err_release;
3968 }
3969
3970 /* validate the extent size is legal now we have the agf locked */
3971 if (XFS_IS_CORRUPT(mp, agbno + len > be32_to_cpu(agf->agf_length))) {
3972 xfs_ag_mark_sick(pag, XFS_SICK_AG_BNOBT);
3973 error = -EFSCORRUPTED;
3974 goto err_release;
3975 }
3976
3977 error = xfs_free_ag_extent(tp, agbp, pag->pag_agno, agbno, len, oinfo,
3978 type);
3979 if (error)
3980 goto err_release;
3981
3982 if (skip_discard)
3983 busy_flags |= XFS_EXTENT_BUSY_SKIP_DISCARD;
3984 xfs_extent_busy_insert(tp, pag, agbno, len, busy_flags);
3985 return 0;
3986
3987err_release:
3988 xfs_trans_brelse(tp, agbp);
3989 return error;
3990}
3991
3992struct xfs_alloc_query_range_info {
3993 xfs_alloc_query_range_fn fn;
3994 void *priv;
3995};
3996
3997/* Format btree record and pass to our callback. */
3998STATIC int
3999xfs_alloc_query_range_helper(
4000 struct xfs_btree_cur *cur,
4001 const union xfs_btree_rec *rec,
4002 void *priv)
4003{
4004 struct xfs_alloc_query_range_info *query = priv;
4005 struct xfs_alloc_rec_incore irec;
4006 xfs_failaddr_t fa;
4007
4008 xfs_alloc_btrec_to_irec(rec, &irec);
4009 fa = xfs_alloc_check_irec(cur->bc_ag.pag, &irec);
4010 if (fa)
4011 return xfs_alloc_complain_bad_rec(cur, fa, &irec);
4012
4013 return query->fn(cur, &irec, query->priv);
4014}
4015
4016/* Find all free space within a given range of blocks. */
4017int
4018xfs_alloc_query_range(
4019 struct xfs_btree_cur *cur,
4020 const struct xfs_alloc_rec_incore *low_rec,
4021 const struct xfs_alloc_rec_incore *high_rec,
4022 xfs_alloc_query_range_fn fn,
4023 void *priv)
4024{
4025 union xfs_btree_irec low_brec = { .a = *low_rec };
4026 union xfs_btree_irec high_brec = { .a = *high_rec };
4027 struct xfs_alloc_query_range_info query = { .priv = priv, .fn = fn };
4028
4029 ASSERT(xfs_btree_is_bno(cur->bc_ops));
4030 return xfs_btree_query_range(cur, &low_brec, &high_brec,
4031 xfs_alloc_query_range_helper, &query);
4032}
4033
4034/* Find all free space records. */
4035int
4036xfs_alloc_query_all(
4037 struct xfs_btree_cur *cur,
4038 xfs_alloc_query_range_fn fn,
4039 void *priv)
4040{
4041 struct xfs_alloc_query_range_info query;
4042
4043 ASSERT(xfs_btree_is_bno(cur->bc_ops));
4044 query.priv = priv;
4045 query.fn = fn;
4046 return xfs_btree_query_all(cur, xfs_alloc_query_range_helper, &query);
4047}
4048
4049/*
4050 * Scan part of the keyspace of the free space and tell us if the area has no
4051 * records, is fully mapped by records, or is partially filled.
4052 */
4053int
4054xfs_alloc_has_records(
4055 struct xfs_btree_cur *cur,
4056 xfs_agblock_t bno,
4057 xfs_extlen_t len,
4058 enum xbtree_recpacking *outcome)
4059{
4060 union xfs_btree_irec low;
4061 union xfs_btree_irec high;
4062
4063 memset(&low, 0, sizeof(low));
4064 low.a.ar_startblock = bno;
4065 memset(&high, 0xFF, sizeof(high));
4066 high.a.ar_startblock = bno + len - 1;
4067
4068 return xfs_btree_has_records(cur, &low, &high, NULL, outcome);
4069}
4070
4071/*
4072 * Walk all the blocks in the AGFL. The @walk_fn can return any negative
4073 * error code or XFS_ITER_*.
4074 */
4075int
4076xfs_agfl_walk(
4077 struct xfs_mount *mp,
4078 struct xfs_agf *agf,
4079 struct xfs_buf *agflbp,
4080 xfs_agfl_walk_fn walk_fn,
4081 void *priv)
4082{
4083 __be32 *agfl_bno;
4084 unsigned int i;
4085 int error;
4086
4087 agfl_bno = xfs_buf_to_agfl_bno(agflbp);
4088 i = be32_to_cpu(agf->agf_flfirst);
4089
4090 /* Nothing to walk in an empty AGFL. */
4091 if (agf->agf_flcount == cpu_to_be32(0))
4092 return 0;
4093
4094 /* Otherwise, walk from first to last, wrapping as needed. */
4095 for (;;) {
4096 error = walk_fn(mp, be32_to_cpu(agfl_bno[i]), priv);
4097 if (error)
4098 return error;
4099 if (i == be32_to_cpu(agf->agf_fllast))
4100 break;
4101 if (++i == xfs_agfl_size(mp))
4102 i = 0;
4103 }
4104
4105 return 0;
4106}
4107
4108int __init
4109xfs_extfree_intent_init_cache(void)
4110{
4111 xfs_extfree_item_cache = kmem_cache_create("xfs_extfree_intent",
4112 sizeof(struct xfs_extent_free_item),
4113 0, 0, NULL);
4114
4115 return xfs_extfree_item_cache != NULL ? 0 : -ENOMEM;
4116}
4117
4118void
4119xfs_extfree_intent_destroy_cache(void)
4120{
4121 kmem_cache_destroy(xfs_extfree_item_cache);
4122 xfs_extfree_item_cache = NULL;
4123}
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright (c) 2000-2002,2005 Silicon Graphics, Inc.
4 * All Rights Reserved.
5 */
6#include "xfs.h"
7#include "xfs_fs.h"
8#include "xfs_format.h"
9#include "xfs_log_format.h"
10#include "xfs_shared.h"
11#include "xfs_trans_resv.h"
12#include "xfs_bit.h"
13#include "xfs_sb.h"
14#include "xfs_mount.h"
15#include "xfs_defer.h"
16#include "xfs_btree.h"
17#include "xfs_rmap.h"
18#include "xfs_alloc_btree.h"
19#include "xfs_alloc.h"
20#include "xfs_extent_busy.h"
21#include "xfs_errortag.h"
22#include "xfs_error.h"
23#include "xfs_trace.h"
24#include "xfs_trans.h"
25#include "xfs_buf_item.h"
26#include "xfs_log.h"
27#include "xfs_ag_resv.h"
28#include "xfs_bmap.h"
29
30extern kmem_zone_t *xfs_bmap_free_item_zone;
31
32struct workqueue_struct *xfs_alloc_wq;
33
34#define XFS_ABSDIFF(a,b) (((a) <= (b)) ? ((b) - (a)) : ((a) - (b)))
35
36#define XFSA_FIXUP_BNO_OK 1
37#define XFSA_FIXUP_CNT_OK 2
38
39STATIC int xfs_alloc_ag_vextent_exact(xfs_alloc_arg_t *);
40STATIC int xfs_alloc_ag_vextent_near(xfs_alloc_arg_t *);
41STATIC int xfs_alloc_ag_vextent_size(xfs_alloc_arg_t *);
42
43/*
44 * Size of the AGFL. For CRC-enabled filesystes we steal a couple of slots in
45 * the beginning of the block for a proper header with the location information
46 * and CRC.
47 */
48unsigned int
49xfs_agfl_size(
50 struct xfs_mount *mp)
51{
52 unsigned int size = mp->m_sb.sb_sectsize;
53
54 if (xfs_sb_version_hascrc(&mp->m_sb))
55 size -= sizeof(struct xfs_agfl);
56
57 return size / sizeof(xfs_agblock_t);
58}
59
60unsigned int
61xfs_refc_block(
62 struct xfs_mount *mp)
63{
64 if (xfs_sb_version_hasrmapbt(&mp->m_sb))
65 return XFS_RMAP_BLOCK(mp) + 1;
66 if (xfs_sb_version_hasfinobt(&mp->m_sb))
67 return XFS_FIBT_BLOCK(mp) + 1;
68 return XFS_IBT_BLOCK(mp) + 1;
69}
70
71xfs_extlen_t
72xfs_prealloc_blocks(
73 struct xfs_mount *mp)
74{
75 if (xfs_sb_version_hasreflink(&mp->m_sb))
76 return xfs_refc_block(mp) + 1;
77 if (xfs_sb_version_hasrmapbt(&mp->m_sb))
78 return XFS_RMAP_BLOCK(mp) + 1;
79 if (xfs_sb_version_hasfinobt(&mp->m_sb))
80 return XFS_FIBT_BLOCK(mp) + 1;
81 return XFS_IBT_BLOCK(mp) + 1;
82}
83
84/*
85 * In order to avoid ENOSPC-related deadlock caused by out-of-order locking of
86 * AGF buffer (PV 947395), we place constraints on the relationship among
87 * actual allocations for data blocks, freelist blocks, and potential file data
88 * bmap btree blocks. However, these restrictions may result in no actual space
89 * allocated for a delayed extent, for example, a data block in a certain AG is
90 * allocated but there is no additional block for the additional bmap btree
91 * block due to a split of the bmap btree of the file. The result of this may
92 * lead to an infinite loop when the file gets flushed to disk and all delayed
93 * extents need to be actually allocated. To get around this, we explicitly set
94 * aside a few blocks which will not be reserved in delayed allocation.
95 *
96 * We need to reserve 4 fsbs _per AG_ for the freelist and 4 more to handle a
97 * potential split of the file's bmap btree.
98 */
99unsigned int
100xfs_alloc_set_aside(
101 struct xfs_mount *mp)
102{
103 return mp->m_sb.sb_agcount * (XFS_ALLOC_AGFL_RESERVE + 4);
104}
105
106/*
107 * When deciding how much space to allocate out of an AG, we limit the
108 * allocation maximum size to the size the AG. However, we cannot use all the
109 * blocks in the AG - some are permanently used by metadata. These
110 * blocks are generally:
111 * - the AG superblock, AGF, AGI and AGFL
112 * - the AGF (bno and cnt) and AGI btree root blocks, and optionally
113 * the AGI free inode and rmap btree root blocks.
114 * - blocks on the AGFL according to xfs_alloc_set_aside() limits
115 * - the rmapbt root block
116 *
117 * The AG headers are sector sized, so the amount of space they take up is
118 * dependent on filesystem geometry. The others are all single blocks.
119 */
120unsigned int
121xfs_alloc_ag_max_usable(
122 struct xfs_mount *mp)
123{
124 unsigned int blocks;
125
126 blocks = XFS_BB_TO_FSB(mp, XFS_FSS_TO_BB(mp, 4)); /* ag headers */
127 blocks += XFS_ALLOC_AGFL_RESERVE;
128 blocks += 3; /* AGF, AGI btree root blocks */
129 if (xfs_sb_version_hasfinobt(&mp->m_sb))
130 blocks++; /* finobt root block */
131 if (xfs_sb_version_hasrmapbt(&mp->m_sb))
132 blocks++; /* rmap root block */
133 if (xfs_sb_version_hasreflink(&mp->m_sb))
134 blocks++; /* refcount root block */
135
136 return mp->m_sb.sb_agblocks - blocks;
137}
138
139/*
140 * Lookup the record equal to [bno, len] in the btree given by cur.
141 */
142STATIC int /* error */
143xfs_alloc_lookup_eq(
144 struct xfs_btree_cur *cur, /* btree cursor */
145 xfs_agblock_t bno, /* starting block of extent */
146 xfs_extlen_t len, /* length of extent */
147 int *stat) /* success/failure */
148{
149 int error;
150
151 cur->bc_rec.a.ar_startblock = bno;
152 cur->bc_rec.a.ar_blockcount = len;
153 error = xfs_btree_lookup(cur, XFS_LOOKUP_EQ, stat);
154 cur->bc_ag.abt.active = (*stat == 1);
155 return error;
156}
157
158/*
159 * Lookup the first record greater than or equal to [bno, len]
160 * in the btree given by cur.
161 */
162int /* error */
163xfs_alloc_lookup_ge(
164 struct xfs_btree_cur *cur, /* btree cursor */
165 xfs_agblock_t bno, /* starting block of extent */
166 xfs_extlen_t len, /* length of extent */
167 int *stat) /* success/failure */
168{
169 int error;
170
171 cur->bc_rec.a.ar_startblock = bno;
172 cur->bc_rec.a.ar_blockcount = len;
173 error = xfs_btree_lookup(cur, XFS_LOOKUP_GE, stat);
174 cur->bc_ag.abt.active = (*stat == 1);
175 return error;
176}
177
178/*
179 * Lookup the first record less than or equal to [bno, len]
180 * in the btree given by cur.
181 */
182int /* error */
183xfs_alloc_lookup_le(
184 struct xfs_btree_cur *cur, /* btree cursor */
185 xfs_agblock_t bno, /* starting block of extent */
186 xfs_extlen_t len, /* length of extent */
187 int *stat) /* success/failure */
188{
189 int error;
190 cur->bc_rec.a.ar_startblock = bno;
191 cur->bc_rec.a.ar_blockcount = len;
192 error = xfs_btree_lookup(cur, XFS_LOOKUP_LE, stat);
193 cur->bc_ag.abt.active = (*stat == 1);
194 return error;
195}
196
197static inline bool
198xfs_alloc_cur_active(
199 struct xfs_btree_cur *cur)
200{
201 return cur && cur->bc_ag.abt.active;
202}
203
204/*
205 * Update the record referred to by cur to the value given
206 * by [bno, len].
207 * This either works (return 0) or gets an EFSCORRUPTED error.
208 */
209STATIC int /* error */
210xfs_alloc_update(
211 struct xfs_btree_cur *cur, /* btree cursor */
212 xfs_agblock_t bno, /* starting block of extent */
213 xfs_extlen_t len) /* length of extent */
214{
215 union xfs_btree_rec rec;
216
217 rec.alloc.ar_startblock = cpu_to_be32(bno);
218 rec.alloc.ar_blockcount = cpu_to_be32(len);
219 return xfs_btree_update(cur, &rec);
220}
221
222/*
223 * Get the data from the pointed-to record.
224 */
225int /* error */
226xfs_alloc_get_rec(
227 struct xfs_btree_cur *cur, /* btree cursor */
228 xfs_agblock_t *bno, /* output: starting block of extent */
229 xfs_extlen_t *len, /* output: length of extent */
230 int *stat) /* output: success/failure */
231{
232 struct xfs_mount *mp = cur->bc_mp;
233 xfs_agnumber_t agno = cur->bc_ag.agno;
234 union xfs_btree_rec *rec;
235 int error;
236
237 error = xfs_btree_get_rec(cur, &rec, stat);
238 if (error || !(*stat))
239 return error;
240
241 *bno = be32_to_cpu(rec->alloc.ar_startblock);
242 *len = be32_to_cpu(rec->alloc.ar_blockcount);
243
244 if (*len == 0)
245 goto out_bad_rec;
246
247 /* check for valid extent range, including overflow */
248 if (!xfs_verify_agbno(mp, agno, *bno))
249 goto out_bad_rec;
250 if (*bno > *bno + *len)
251 goto out_bad_rec;
252 if (!xfs_verify_agbno(mp, agno, *bno + *len - 1))
253 goto out_bad_rec;
254
255 return 0;
256
257out_bad_rec:
258 xfs_warn(mp,
259 "%s Freespace BTree record corruption in AG %d detected!",
260 cur->bc_btnum == XFS_BTNUM_BNO ? "Block" : "Size", agno);
261 xfs_warn(mp,
262 "start block 0x%x block count 0x%x", *bno, *len);
263 return -EFSCORRUPTED;
264}
265
266/*
267 * Compute aligned version of the found extent.
268 * Takes alignment and min length into account.
269 */
270STATIC bool
271xfs_alloc_compute_aligned(
272 xfs_alloc_arg_t *args, /* allocation argument structure */
273 xfs_agblock_t foundbno, /* starting block in found extent */
274 xfs_extlen_t foundlen, /* length in found extent */
275 xfs_agblock_t *resbno, /* result block number */
276 xfs_extlen_t *reslen, /* result length */
277 unsigned *busy_gen)
278{
279 xfs_agblock_t bno = foundbno;
280 xfs_extlen_t len = foundlen;
281 xfs_extlen_t diff;
282 bool busy;
283
284 /* Trim busy sections out of found extent */
285 busy = xfs_extent_busy_trim(args, &bno, &len, busy_gen);
286
287 /*
288 * If we have a largish extent that happens to start before min_agbno,
289 * see if we can shift it into range...
290 */
291 if (bno < args->min_agbno && bno + len > args->min_agbno) {
292 diff = args->min_agbno - bno;
293 if (len > diff) {
294 bno += diff;
295 len -= diff;
296 }
297 }
298
299 if (args->alignment > 1 && len >= args->minlen) {
300 xfs_agblock_t aligned_bno = roundup(bno, args->alignment);
301
302 diff = aligned_bno - bno;
303
304 *resbno = aligned_bno;
305 *reslen = diff >= len ? 0 : len - diff;
306 } else {
307 *resbno = bno;
308 *reslen = len;
309 }
310
311 return busy;
312}
313
314/*
315 * Compute best start block and diff for "near" allocations.
316 * freelen >= wantlen already checked by caller.
317 */
318STATIC xfs_extlen_t /* difference value (absolute) */
319xfs_alloc_compute_diff(
320 xfs_agblock_t wantbno, /* target starting block */
321 xfs_extlen_t wantlen, /* target length */
322 xfs_extlen_t alignment, /* target alignment */
323 int datatype, /* are we allocating data? */
324 xfs_agblock_t freebno, /* freespace's starting block */
325 xfs_extlen_t freelen, /* freespace's length */
326 xfs_agblock_t *newbnop) /* result: best start block from free */
327{
328 xfs_agblock_t freeend; /* end of freespace extent */
329 xfs_agblock_t newbno1; /* return block number */
330 xfs_agblock_t newbno2; /* other new block number */
331 xfs_extlen_t newlen1=0; /* length with newbno1 */
332 xfs_extlen_t newlen2=0; /* length with newbno2 */
333 xfs_agblock_t wantend; /* end of target extent */
334 bool userdata = datatype & XFS_ALLOC_USERDATA;
335
336 ASSERT(freelen >= wantlen);
337 freeend = freebno + freelen;
338 wantend = wantbno + wantlen;
339 /*
340 * We want to allocate from the start of a free extent if it is past
341 * the desired block or if we are allocating user data and the free
342 * extent is before desired block. The second case is there to allow
343 * for contiguous allocation from the remaining free space if the file
344 * grows in the short term.
345 */
346 if (freebno >= wantbno || (userdata && freeend < wantend)) {
347 if ((newbno1 = roundup(freebno, alignment)) >= freeend)
348 newbno1 = NULLAGBLOCK;
349 } else if (freeend >= wantend && alignment > 1) {
350 newbno1 = roundup(wantbno, alignment);
351 newbno2 = newbno1 - alignment;
352 if (newbno1 >= freeend)
353 newbno1 = NULLAGBLOCK;
354 else
355 newlen1 = XFS_EXTLEN_MIN(wantlen, freeend - newbno1);
356 if (newbno2 < freebno)
357 newbno2 = NULLAGBLOCK;
358 else
359 newlen2 = XFS_EXTLEN_MIN(wantlen, freeend - newbno2);
360 if (newbno1 != NULLAGBLOCK && newbno2 != NULLAGBLOCK) {
361 if (newlen1 < newlen2 ||
362 (newlen1 == newlen2 &&
363 XFS_ABSDIFF(newbno1, wantbno) >
364 XFS_ABSDIFF(newbno2, wantbno)))
365 newbno1 = newbno2;
366 } else if (newbno2 != NULLAGBLOCK)
367 newbno1 = newbno2;
368 } else if (freeend >= wantend) {
369 newbno1 = wantbno;
370 } else if (alignment > 1) {
371 newbno1 = roundup(freeend - wantlen, alignment);
372 if (newbno1 > freeend - wantlen &&
373 newbno1 - alignment >= freebno)
374 newbno1 -= alignment;
375 else if (newbno1 >= freeend)
376 newbno1 = NULLAGBLOCK;
377 } else
378 newbno1 = freeend - wantlen;
379 *newbnop = newbno1;
380 return newbno1 == NULLAGBLOCK ? 0 : XFS_ABSDIFF(newbno1, wantbno);
381}
382
383/*
384 * Fix up the length, based on mod and prod.
385 * len should be k * prod + mod for some k.
386 * If len is too small it is returned unchanged.
387 * If len hits maxlen it is left alone.
388 */
389STATIC void
390xfs_alloc_fix_len(
391 xfs_alloc_arg_t *args) /* allocation argument structure */
392{
393 xfs_extlen_t k;
394 xfs_extlen_t rlen;
395
396 ASSERT(args->mod < args->prod);
397 rlen = args->len;
398 ASSERT(rlen >= args->minlen);
399 ASSERT(rlen <= args->maxlen);
400 if (args->prod <= 1 || rlen < args->mod || rlen == args->maxlen ||
401 (args->mod == 0 && rlen < args->prod))
402 return;
403 k = rlen % args->prod;
404 if (k == args->mod)
405 return;
406 if (k > args->mod)
407 rlen = rlen - (k - args->mod);
408 else
409 rlen = rlen - args->prod + (args->mod - k);
410 /* casts to (int) catch length underflows */
411 if ((int)rlen < (int)args->minlen)
412 return;
413 ASSERT(rlen >= args->minlen && rlen <= args->maxlen);
414 ASSERT(rlen % args->prod == args->mod);
415 ASSERT(args->pag->pagf_freeblks + args->pag->pagf_flcount >=
416 rlen + args->minleft);
417 args->len = rlen;
418}
419
420/*
421 * Update the two btrees, logically removing from freespace the extent
422 * starting at rbno, rlen blocks. The extent is contained within the
423 * actual (current) free extent fbno for flen blocks.
424 * Flags are passed in indicating whether the cursors are set to the
425 * relevant records.
426 */
427STATIC int /* error code */
428xfs_alloc_fixup_trees(
429 xfs_btree_cur_t *cnt_cur, /* cursor for by-size btree */
430 xfs_btree_cur_t *bno_cur, /* cursor for by-block btree */
431 xfs_agblock_t fbno, /* starting block of free extent */
432 xfs_extlen_t flen, /* length of free extent */
433 xfs_agblock_t rbno, /* starting block of returned extent */
434 xfs_extlen_t rlen, /* length of returned extent */
435 int flags) /* flags, XFSA_FIXUP_... */
436{
437 int error; /* error code */
438 int i; /* operation results */
439 xfs_agblock_t nfbno1; /* first new free startblock */
440 xfs_agblock_t nfbno2; /* second new free startblock */
441 xfs_extlen_t nflen1=0; /* first new free length */
442 xfs_extlen_t nflen2=0; /* second new free length */
443 struct xfs_mount *mp;
444
445 mp = cnt_cur->bc_mp;
446
447 /*
448 * Look up the record in the by-size tree if necessary.
449 */
450 if (flags & XFSA_FIXUP_CNT_OK) {
451#ifdef DEBUG
452 if ((error = xfs_alloc_get_rec(cnt_cur, &nfbno1, &nflen1, &i)))
453 return error;
454 if (XFS_IS_CORRUPT(mp,
455 i != 1 ||
456 nfbno1 != fbno ||
457 nflen1 != flen))
458 return -EFSCORRUPTED;
459#endif
460 } else {
461 if ((error = xfs_alloc_lookup_eq(cnt_cur, fbno, flen, &i)))
462 return error;
463 if (XFS_IS_CORRUPT(mp, i != 1))
464 return -EFSCORRUPTED;
465 }
466 /*
467 * Look up the record in the by-block tree if necessary.
468 */
469 if (flags & XFSA_FIXUP_BNO_OK) {
470#ifdef DEBUG
471 if ((error = xfs_alloc_get_rec(bno_cur, &nfbno1, &nflen1, &i)))
472 return error;
473 if (XFS_IS_CORRUPT(mp,
474 i != 1 ||
475 nfbno1 != fbno ||
476 nflen1 != flen))
477 return -EFSCORRUPTED;
478#endif
479 } else {
480 if ((error = xfs_alloc_lookup_eq(bno_cur, fbno, flen, &i)))
481 return error;
482 if (XFS_IS_CORRUPT(mp, i != 1))
483 return -EFSCORRUPTED;
484 }
485
486#ifdef DEBUG
487 if (bno_cur->bc_nlevels == 1 && cnt_cur->bc_nlevels == 1) {
488 struct xfs_btree_block *bnoblock;
489 struct xfs_btree_block *cntblock;
490
491 bnoblock = XFS_BUF_TO_BLOCK(bno_cur->bc_bufs[0]);
492 cntblock = XFS_BUF_TO_BLOCK(cnt_cur->bc_bufs[0]);
493
494 if (XFS_IS_CORRUPT(mp,
495 bnoblock->bb_numrecs !=
496 cntblock->bb_numrecs))
497 return -EFSCORRUPTED;
498 }
499#endif
500
501 /*
502 * Deal with all four cases: the allocated record is contained
503 * within the freespace record, so we can have new freespace
504 * at either (or both) end, or no freespace remaining.
505 */
506 if (rbno == fbno && rlen == flen)
507 nfbno1 = nfbno2 = NULLAGBLOCK;
508 else if (rbno == fbno) {
509 nfbno1 = rbno + rlen;
510 nflen1 = flen - rlen;
511 nfbno2 = NULLAGBLOCK;
512 } else if (rbno + rlen == fbno + flen) {
513 nfbno1 = fbno;
514 nflen1 = flen - rlen;
515 nfbno2 = NULLAGBLOCK;
516 } else {
517 nfbno1 = fbno;
518 nflen1 = rbno - fbno;
519 nfbno2 = rbno + rlen;
520 nflen2 = (fbno + flen) - nfbno2;
521 }
522 /*
523 * Delete the entry from the by-size btree.
524 */
525 if ((error = xfs_btree_delete(cnt_cur, &i)))
526 return error;
527 if (XFS_IS_CORRUPT(mp, i != 1))
528 return -EFSCORRUPTED;
529 /*
530 * Add new by-size btree entry(s).
531 */
532 if (nfbno1 != NULLAGBLOCK) {
533 if ((error = xfs_alloc_lookup_eq(cnt_cur, nfbno1, nflen1, &i)))
534 return error;
535 if (XFS_IS_CORRUPT(mp, i != 0))
536 return -EFSCORRUPTED;
537 if ((error = xfs_btree_insert(cnt_cur, &i)))
538 return error;
539 if (XFS_IS_CORRUPT(mp, i != 1))
540 return -EFSCORRUPTED;
541 }
542 if (nfbno2 != NULLAGBLOCK) {
543 if ((error = xfs_alloc_lookup_eq(cnt_cur, nfbno2, nflen2, &i)))
544 return error;
545 if (XFS_IS_CORRUPT(mp, i != 0))
546 return -EFSCORRUPTED;
547 if ((error = xfs_btree_insert(cnt_cur, &i)))
548 return error;
549 if (XFS_IS_CORRUPT(mp, i != 1))
550 return -EFSCORRUPTED;
551 }
552 /*
553 * Fix up the by-block btree entry(s).
554 */
555 if (nfbno1 == NULLAGBLOCK) {
556 /*
557 * No remaining freespace, just delete the by-block tree entry.
558 */
559 if ((error = xfs_btree_delete(bno_cur, &i)))
560 return error;
561 if (XFS_IS_CORRUPT(mp, i != 1))
562 return -EFSCORRUPTED;
563 } else {
564 /*
565 * Update the by-block entry to start later|be shorter.
566 */
567 if ((error = xfs_alloc_update(bno_cur, nfbno1, nflen1)))
568 return error;
569 }
570 if (nfbno2 != NULLAGBLOCK) {
571 /*
572 * 2 resulting free entries, need to add one.
573 */
574 if ((error = xfs_alloc_lookup_eq(bno_cur, nfbno2, nflen2, &i)))
575 return error;
576 if (XFS_IS_CORRUPT(mp, i != 0))
577 return -EFSCORRUPTED;
578 if ((error = xfs_btree_insert(bno_cur, &i)))
579 return error;
580 if (XFS_IS_CORRUPT(mp, i != 1))
581 return -EFSCORRUPTED;
582 }
583 return 0;
584}
585
586static xfs_failaddr_t
587xfs_agfl_verify(
588 struct xfs_buf *bp)
589{
590 struct xfs_mount *mp = bp->b_mount;
591 struct xfs_agfl *agfl = XFS_BUF_TO_AGFL(bp);
592 __be32 *agfl_bno = xfs_buf_to_agfl_bno(bp);
593 int i;
594
595 /*
596 * There is no verification of non-crc AGFLs because mkfs does not
597 * initialise the AGFL to zero or NULL. Hence the only valid part of the
598 * AGFL is what the AGF says is active. We can't get to the AGF, so we
599 * can't verify just those entries are valid.
600 */
601 if (!xfs_sb_version_hascrc(&mp->m_sb))
602 return NULL;
603
604 if (!xfs_verify_magic(bp, agfl->agfl_magicnum))
605 return __this_address;
606 if (!uuid_equal(&agfl->agfl_uuid, &mp->m_sb.sb_meta_uuid))
607 return __this_address;
608 /*
609 * during growfs operations, the perag is not fully initialised,
610 * so we can't use it for any useful checking. growfs ensures we can't
611 * use it by using uncached buffers that don't have the perag attached
612 * so we can detect and avoid this problem.
613 */
614 if (bp->b_pag && be32_to_cpu(agfl->agfl_seqno) != bp->b_pag->pag_agno)
615 return __this_address;
616
617 for (i = 0; i < xfs_agfl_size(mp); i++) {
618 if (be32_to_cpu(agfl_bno[i]) != NULLAGBLOCK &&
619 be32_to_cpu(agfl_bno[i]) >= mp->m_sb.sb_agblocks)
620 return __this_address;
621 }
622
623 if (!xfs_log_check_lsn(mp, be64_to_cpu(XFS_BUF_TO_AGFL(bp)->agfl_lsn)))
624 return __this_address;
625 return NULL;
626}
627
628static void
629xfs_agfl_read_verify(
630 struct xfs_buf *bp)
631{
632 struct xfs_mount *mp = bp->b_mount;
633 xfs_failaddr_t fa;
634
635 /*
636 * There is no verification of non-crc AGFLs because mkfs does not
637 * initialise the AGFL to zero or NULL. Hence the only valid part of the
638 * AGFL is what the AGF says is active. We can't get to the AGF, so we
639 * can't verify just those entries are valid.
640 */
641 if (!xfs_sb_version_hascrc(&mp->m_sb))
642 return;
643
644 if (!xfs_buf_verify_cksum(bp, XFS_AGFL_CRC_OFF))
645 xfs_verifier_error(bp, -EFSBADCRC, __this_address);
646 else {
647 fa = xfs_agfl_verify(bp);
648 if (fa)
649 xfs_verifier_error(bp, -EFSCORRUPTED, fa);
650 }
651}
652
653static void
654xfs_agfl_write_verify(
655 struct xfs_buf *bp)
656{
657 struct xfs_mount *mp = bp->b_mount;
658 struct xfs_buf_log_item *bip = bp->b_log_item;
659 xfs_failaddr_t fa;
660
661 /* no verification of non-crc AGFLs */
662 if (!xfs_sb_version_hascrc(&mp->m_sb))
663 return;
664
665 fa = xfs_agfl_verify(bp);
666 if (fa) {
667 xfs_verifier_error(bp, -EFSCORRUPTED, fa);
668 return;
669 }
670
671 if (bip)
672 XFS_BUF_TO_AGFL(bp)->agfl_lsn = cpu_to_be64(bip->bli_item.li_lsn);
673
674 xfs_buf_update_cksum(bp, XFS_AGFL_CRC_OFF);
675}
676
677const struct xfs_buf_ops xfs_agfl_buf_ops = {
678 .name = "xfs_agfl",
679 .magic = { cpu_to_be32(XFS_AGFL_MAGIC), cpu_to_be32(XFS_AGFL_MAGIC) },
680 .verify_read = xfs_agfl_read_verify,
681 .verify_write = xfs_agfl_write_verify,
682 .verify_struct = xfs_agfl_verify,
683};
684
685/*
686 * Read in the allocation group free block array.
687 */
688int /* error */
689xfs_alloc_read_agfl(
690 xfs_mount_t *mp, /* mount point structure */
691 xfs_trans_t *tp, /* transaction pointer */
692 xfs_agnumber_t agno, /* allocation group number */
693 xfs_buf_t **bpp) /* buffer for the ag free block array */
694{
695 xfs_buf_t *bp; /* return value */
696 int error;
697
698 ASSERT(agno != NULLAGNUMBER);
699 error = xfs_trans_read_buf(
700 mp, tp, mp->m_ddev_targp,
701 XFS_AG_DADDR(mp, agno, XFS_AGFL_DADDR(mp)),
702 XFS_FSS_TO_BB(mp, 1), 0, &bp, &xfs_agfl_buf_ops);
703 if (error)
704 return error;
705 xfs_buf_set_ref(bp, XFS_AGFL_REF);
706 *bpp = bp;
707 return 0;
708}
709
710STATIC int
711xfs_alloc_update_counters(
712 struct xfs_trans *tp,
713 struct xfs_buf *agbp,
714 long len)
715{
716 struct xfs_agf *agf = agbp->b_addr;
717
718 agbp->b_pag->pagf_freeblks += len;
719 be32_add_cpu(&agf->agf_freeblks, len);
720
721 xfs_trans_agblocks_delta(tp, len);
722 if (unlikely(be32_to_cpu(agf->agf_freeblks) >
723 be32_to_cpu(agf->agf_length))) {
724 xfs_buf_mark_corrupt(agbp);
725 return -EFSCORRUPTED;
726 }
727
728 xfs_alloc_log_agf(tp, agbp, XFS_AGF_FREEBLKS);
729 return 0;
730}
731
732/*
733 * Block allocation algorithm and data structures.
734 */
735struct xfs_alloc_cur {
736 struct xfs_btree_cur *cnt; /* btree cursors */
737 struct xfs_btree_cur *bnolt;
738 struct xfs_btree_cur *bnogt;
739 xfs_extlen_t cur_len;/* current search length */
740 xfs_agblock_t rec_bno;/* extent startblock */
741 xfs_extlen_t rec_len;/* extent length */
742 xfs_agblock_t bno; /* alloc bno */
743 xfs_extlen_t len; /* alloc len */
744 xfs_extlen_t diff; /* diff from search bno */
745 unsigned int busy_gen;/* busy state */
746 bool busy;
747};
748
749/*
750 * Set up cursors, etc. in the extent allocation cursor. This function can be
751 * called multiple times to reset an initialized structure without having to
752 * reallocate cursors.
753 */
754static int
755xfs_alloc_cur_setup(
756 struct xfs_alloc_arg *args,
757 struct xfs_alloc_cur *acur)
758{
759 int error;
760 int i;
761
762 ASSERT(args->alignment == 1 || args->type != XFS_ALLOCTYPE_THIS_BNO);
763
764 acur->cur_len = args->maxlen;
765 acur->rec_bno = 0;
766 acur->rec_len = 0;
767 acur->bno = 0;
768 acur->len = 0;
769 acur->diff = -1;
770 acur->busy = false;
771 acur->busy_gen = 0;
772
773 /*
774 * Perform an initial cntbt lookup to check for availability of maxlen
775 * extents. If this fails, we'll return -ENOSPC to signal the caller to
776 * attempt a small allocation.
777 */
778 if (!acur->cnt)
779 acur->cnt = xfs_allocbt_init_cursor(args->mp, args->tp,
780 args->agbp, args->agno, XFS_BTNUM_CNT);
781 error = xfs_alloc_lookup_ge(acur->cnt, 0, args->maxlen, &i);
782 if (error)
783 return error;
784
785 /*
786 * Allocate the bnobt left and right search cursors.
787 */
788 if (!acur->bnolt)
789 acur->bnolt = xfs_allocbt_init_cursor(args->mp, args->tp,
790 args->agbp, args->agno, XFS_BTNUM_BNO);
791 if (!acur->bnogt)
792 acur->bnogt = xfs_allocbt_init_cursor(args->mp, args->tp,
793 args->agbp, args->agno, XFS_BTNUM_BNO);
794 return i == 1 ? 0 : -ENOSPC;
795}
796
797static void
798xfs_alloc_cur_close(
799 struct xfs_alloc_cur *acur,
800 bool error)
801{
802 int cur_error = XFS_BTREE_NOERROR;
803
804 if (error)
805 cur_error = XFS_BTREE_ERROR;
806
807 if (acur->cnt)
808 xfs_btree_del_cursor(acur->cnt, cur_error);
809 if (acur->bnolt)
810 xfs_btree_del_cursor(acur->bnolt, cur_error);
811 if (acur->bnogt)
812 xfs_btree_del_cursor(acur->bnogt, cur_error);
813 acur->cnt = acur->bnolt = acur->bnogt = NULL;
814}
815
816/*
817 * Check an extent for allocation and track the best available candidate in the
818 * allocation structure. The cursor is deactivated if it has entered an out of
819 * range state based on allocation arguments. Optionally return the extent
820 * extent geometry and allocation status if requested by the caller.
821 */
822static int
823xfs_alloc_cur_check(
824 struct xfs_alloc_arg *args,
825 struct xfs_alloc_cur *acur,
826 struct xfs_btree_cur *cur,
827 int *new)
828{
829 int error, i;
830 xfs_agblock_t bno, bnoa, bnew;
831 xfs_extlen_t len, lena, diff = -1;
832 bool busy;
833 unsigned busy_gen = 0;
834 bool deactivate = false;
835 bool isbnobt = cur->bc_btnum == XFS_BTNUM_BNO;
836
837 *new = 0;
838
839 error = xfs_alloc_get_rec(cur, &bno, &len, &i);
840 if (error)
841 return error;
842 if (XFS_IS_CORRUPT(args->mp, i != 1))
843 return -EFSCORRUPTED;
844
845 /*
846 * Check minlen and deactivate a cntbt cursor if out of acceptable size
847 * range (i.e., walking backwards looking for a minlen extent).
848 */
849 if (len < args->minlen) {
850 deactivate = !isbnobt;
851 goto out;
852 }
853
854 busy = xfs_alloc_compute_aligned(args, bno, len, &bnoa, &lena,
855 &busy_gen);
856 acur->busy |= busy;
857 if (busy)
858 acur->busy_gen = busy_gen;
859 /* deactivate a bnobt cursor outside of locality range */
860 if (bnoa < args->min_agbno || bnoa > args->max_agbno) {
861 deactivate = isbnobt;
862 goto out;
863 }
864 if (lena < args->minlen)
865 goto out;
866
867 args->len = XFS_EXTLEN_MIN(lena, args->maxlen);
868 xfs_alloc_fix_len(args);
869 ASSERT(args->len >= args->minlen);
870 if (args->len < acur->len)
871 goto out;
872
873 /*
874 * We have an aligned record that satisfies minlen and beats or matches
875 * the candidate extent size. Compare locality for near allocation mode.
876 */
877 ASSERT(args->type == XFS_ALLOCTYPE_NEAR_BNO);
878 diff = xfs_alloc_compute_diff(args->agbno, args->len,
879 args->alignment, args->datatype,
880 bnoa, lena, &bnew);
881 if (bnew == NULLAGBLOCK)
882 goto out;
883
884 /*
885 * Deactivate a bnobt cursor with worse locality than the current best.
886 */
887 if (diff > acur->diff) {
888 deactivate = isbnobt;
889 goto out;
890 }
891
892 ASSERT(args->len > acur->len ||
893 (args->len == acur->len && diff <= acur->diff));
894 acur->rec_bno = bno;
895 acur->rec_len = len;
896 acur->bno = bnew;
897 acur->len = args->len;
898 acur->diff = diff;
899 *new = 1;
900
901 /*
902 * We're done if we found a perfect allocation. This only deactivates
903 * the current cursor, but this is just an optimization to terminate a
904 * cntbt search that otherwise runs to the edge of the tree.
905 */
906 if (acur->diff == 0 && acur->len == args->maxlen)
907 deactivate = true;
908out:
909 if (deactivate)
910 cur->bc_ag.abt.active = false;
911 trace_xfs_alloc_cur_check(args->mp, cur->bc_btnum, bno, len, diff,
912 *new);
913 return 0;
914}
915
916/*
917 * Complete an allocation of a candidate extent. Remove the extent from both
918 * trees and update the args structure.
919 */
920STATIC int
921xfs_alloc_cur_finish(
922 struct xfs_alloc_arg *args,
923 struct xfs_alloc_cur *acur)
924{
925 struct xfs_agf __maybe_unused *agf = args->agbp->b_addr;
926 int error;
927
928 ASSERT(acur->cnt && acur->bnolt);
929 ASSERT(acur->bno >= acur->rec_bno);
930 ASSERT(acur->bno + acur->len <= acur->rec_bno + acur->rec_len);
931 ASSERT(acur->rec_bno + acur->rec_len <= be32_to_cpu(agf->agf_length));
932
933 error = xfs_alloc_fixup_trees(acur->cnt, acur->bnolt, acur->rec_bno,
934 acur->rec_len, acur->bno, acur->len, 0);
935 if (error)
936 return error;
937
938 args->agbno = acur->bno;
939 args->len = acur->len;
940 args->wasfromfl = 0;
941
942 trace_xfs_alloc_cur(args);
943 return 0;
944}
945
946/*
947 * Locality allocation lookup algorithm. This expects a cntbt cursor and uses
948 * bno optimized lookup to search for extents with ideal size and locality.
949 */
950STATIC int
951xfs_alloc_cntbt_iter(
952 struct xfs_alloc_arg *args,
953 struct xfs_alloc_cur *acur)
954{
955 struct xfs_btree_cur *cur = acur->cnt;
956 xfs_agblock_t bno;
957 xfs_extlen_t len, cur_len;
958 int error;
959 int i;
960
961 if (!xfs_alloc_cur_active(cur))
962 return 0;
963
964 /* locality optimized lookup */
965 cur_len = acur->cur_len;
966 error = xfs_alloc_lookup_ge(cur, args->agbno, cur_len, &i);
967 if (error)
968 return error;
969 if (i == 0)
970 return 0;
971 error = xfs_alloc_get_rec(cur, &bno, &len, &i);
972 if (error)
973 return error;
974
975 /* check the current record and update search length from it */
976 error = xfs_alloc_cur_check(args, acur, cur, &i);
977 if (error)
978 return error;
979 ASSERT(len >= acur->cur_len);
980 acur->cur_len = len;
981
982 /*
983 * We looked up the first record >= [agbno, len] above. The agbno is a
984 * secondary key and so the current record may lie just before or after
985 * agbno. If it is past agbno, check the previous record too so long as
986 * the length matches as it may be closer. Don't check a smaller record
987 * because that could deactivate our cursor.
988 */
989 if (bno > args->agbno) {
990 error = xfs_btree_decrement(cur, 0, &i);
991 if (!error && i) {
992 error = xfs_alloc_get_rec(cur, &bno, &len, &i);
993 if (!error && i && len == acur->cur_len)
994 error = xfs_alloc_cur_check(args, acur, cur,
995 &i);
996 }
997 if (error)
998 return error;
999 }
1000
1001 /*
1002 * Increment the search key until we find at least one allocation
1003 * candidate or if the extent we found was larger. Otherwise, double the
1004 * search key to optimize the search. Efficiency is more important here
1005 * than absolute best locality.
1006 */
1007 cur_len <<= 1;
1008 if (!acur->len || acur->cur_len >= cur_len)
1009 acur->cur_len++;
1010 else
1011 acur->cur_len = cur_len;
1012
1013 return error;
1014}
1015
1016/*
1017 * Deal with the case where only small freespaces remain. Either return the
1018 * contents of the last freespace record, or allocate space from the freelist if
1019 * there is nothing in the tree.
1020 */
1021STATIC int /* error */
1022xfs_alloc_ag_vextent_small(
1023 struct xfs_alloc_arg *args, /* allocation argument structure */
1024 struct xfs_btree_cur *ccur, /* optional by-size cursor */
1025 xfs_agblock_t *fbnop, /* result block number */
1026 xfs_extlen_t *flenp, /* result length */
1027 int *stat) /* status: 0-freelist, 1-normal/none */
1028{
1029 struct xfs_agf *agf = args->agbp->b_addr;
1030 int error = 0;
1031 xfs_agblock_t fbno = NULLAGBLOCK;
1032 xfs_extlen_t flen = 0;
1033 int i = 0;
1034
1035 /*
1036 * If a cntbt cursor is provided, try to allocate the largest record in
1037 * the tree. Try the AGFL if the cntbt is empty, otherwise fail the
1038 * allocation. Make sure to respect minleft even when pulling from the
1039 * freelist.
1040 */
1041 if (ccur)
1042 error = xfs_btree_decrement(ccur, 0, &i);
1043 if (error)
1044 goto error;
1045 if (i) {
1046 error = xfs_alloc_get_rec(ccur, &fbno, &flen, &i);
1047 if (error)
1048 goto error;
1049 if (XFS_IS_CORRUPT(args->mp, i != 1)) {
1050 error = -EFSCORRUPTED;
1051 goto error;
1052 }
1053 goto out;
1054 }
1055
1056 if (args->minlen != 1 || args->alignment != 1 ||
1057 args->resv == XFS_AG_RESV_AGFL ||
1058 be32_to_cpu(agf->agf_flcount) <= args->minleft)
1059 goto out;
1060
1061 error = xfs_alloc_get_freelist(args->tp, args->agbp, &fbno, 0);
1062 if (error)
1063 goto error;
1064 if (fbno == NULLAGBLOCK)
1065 goto out;
1066
1067 xfs_extent_busy_reuse(args->mp, args->agno, fbno, 1,
1068 (args->datatype & XFS_ALLOC_NOBUSY));
1069
1070 if (args->datatype & XFS_ALLOC_USERDATA) {
1071 struct xfs_buf *bp;
1072
1073 error = xfs_trans_get_buf(args->tp, args->mp->m_ddev_targp,
1074 XFS_AGB_TO_DADDR(args->mp, args->agno, fbno),
1075 args->mp->m_bsize, 0, &bp);
1076 if (error)
1077 goto error;
1078 xfs_trans_binval(args->tp, bp);
1079 }
1080 *fbnop = args->agbno = fbno;
1081 *flenp = args->len = 1;
1082 if (XFS_IS_CORRUPT(args->mp, fbno >= be32_to_cpu(agf->agf_length))) {
1083 error = -EFSCORRUPTED;
1084 goto error;
1085 }
1086 args->wasfromfl = 1;
1087 trace_xfs_alloc_small_freelist(args);
1088
1089 /*
1090 * If we're feeding an AGFL block to something that doesn't live in the
1091 * free space, we need to clear out the OWN_AG rmap.
1092 */
1093 error = xfs_rmap_free(args->tp, args->agbp, args->agno, fbno, 1,
1094 &XFS_RMAP_OINFO_AG);
1095 if (error)
1096 goto error;
1097
1098 *stat = 0;
1099 return 0;
1100
1101out:
1102 /*
1103 * Can't do the allocation, give up.
1104 */
1105 if (flen < args->minlen) {
1106 args->agbno = NULLAGBLOCK;
1107 trace_xfs_alloc_small_notenough(args);
1108 flen = 0;
1109 }
1110 *fbnop = fbno;
1111 *flenp = flen;
1112 *stat = 1;
1113 trace_xfs_alloc_small_done(args);
1114 return 0;
1115
1116error:
1117 trace_xfs_alloc_small_error(args);
1118 return error;
1119}
1120
1121/*
1122 * Allocate a variable extent in the allocation group agno.
1123 * Type and bno are used to determine where in the allocation group the
1124 * extent will start.
1125 * Extent's length (returned in *len) will be between minlen and maxlen,
1126 * and of the form k * prod + mod unless there's nothing that large.
1127 * Return the starting a.g. block, or NULLAGBLOCK if we can't do it.
1128 */
1129STATIC int /* error */
1130xfs_alloc_ag_vextent(
1131 xfs_alloc_arg_t *args) /* argument structure for allocation */
1132{
1133 int error=0;
1134
1135 ASSERT(args->minlen > 0);
1136 ASSERT(args->maxlen > 0);
1137 ASSERT(args->minlen <= args->maxlen);
1138 ASSERT(args->mod < args->prod);
1139 ASSERT(args->alignment > 0);
1140
1141 /*
1142 * Branch to correct routine based on the type.
1143 */
1144 args->wasfromfl = 0;
1145 switch (args->type) {
1146 case XFS_ALLOCTYPE_THIS_AG:
1147 error = xfs_alloc_ag_vextent_size(args);
1148 break;
1149 case XFS_ALLOCTYPE_NEAR_BNO:
1150 error = xfs_alloc_ag_vextent_near(args);
1151 break;
1152 case XFS_ALLOCTYPE_THIS_BNO:
1153 error = xfs_alloc_ag_vextent_exact(args);
1154 break;
1155 default:
1156 ASSERT(0);
1157 /* NOTREACHED */
1158 }
1159
1160 if (error || args->agbno == NULLAGBLOCK)
1161 return error;
1162
1163 ASSERT(args->len >= args->minlen);
1164 ASSERT(args->len <= args->maxlen);
1165 ASSERT(!args->wasfromfl || args->resv != XFS_AG_RESV_AGFL);
1166 ASSERT(args->agbno % args->alignment == 0);
1167
1168 /* if not file data, insert new block into the reverse map btree */
1169 if (!xfs_rmap_should_skip_owner_update(&args->oinfo)) {
1170 error = xfs_rmap_alloc(args->tp, args->agbp, args->agno,
1171 args->agbno, args->len, &args->oinfo);
1172 if (error)
1173 return error;
1174 }
1175
1176 if (!args->wasfromfl) {
1177 error = xfs_alloc_update_counters(args->tp, args->agbp,
1178 -((long)(args->len)));
1179 if (error)
1180 return error;
1181
1182 ASSERT(!xfs_extent_busy_search(args->mp, args->agno,
1183 args->agbno, args->len));
1184 }
1185
1186 xfs_ag_resv_alloc_extent(args->pag, args->resv, args);
1187
1188 XFS_STATS_INC(args->mp, xs_allocx);
1189 XFS_STATS_ADD(args->mp, xs_allocb, args->len);
1190 return error;
1191}
1192
1193/*
1194 * Allocate a variable extent at exactly agno/bno.
1195 * Extent's length (returned in *len) will be between minlen and maxlen,
1196 * and of the form k * prod + mod unless there's nothing that large.
1197 * Return the starting a.g. block (bno), or NULLAGBLOCK if we can't do it.
1198 */
1199STATIC int /* error */
1200xfs_alloc_ag_vextent_exact(
1201 xfs_alloc_arg_t *args) /* allocation argument structure */
1202{
1203 struct xfs_agf __maybe_unused *agf = args->agbp->b_addr;
1204 xfs_btree_cur_t *bno_cur;/* by block-number btree cursor */
1205 xfs_btree_cur_t *cnt_cur;/* by count btree cursor */
1206 int error;
1207 xfs_agblock_t fbno; /* start block of found extent */
1208 xfs_extlen_t flen; /* length of found extent */
1209 xfs_agblock_t tbno; /* start block of busy extent */
1210 xfs_extlen_t tlen; /* length of busy extent */
1211 xfs_agblock_t tend; /* end block of busy extent */
1212 int i; /* success/failure of operation */
1213 unsigned busy_gen;
1214
1215 ASSERT(args->alignment == 1);
1216
1217 /*
1218 * Allocate/initialize a cursor for the by-number freespace btree.
1219 */
1220 bno_cur = xfs_allocbt_init_cursor(args->mp, args->tp, args->agbp,
1221 args->agno, XFS_BTNUM_BNO);
1222
1223 /*
1224 * Lookup bno and minlen in the btree (minlen is irrelevant, really).
1225 * Look for the closest free block <= bno, it must contain bno
1226 * if any free block does.
1227 */
1228 error = xfs_alloc_lookup_le(bno_cur, args->agbno, args->minlen, &i);
1229 if (error)
1230 goto error0;
1231 if (!i)
1232 goto not_found;
1233
1234 /*
1235 * Grab the freespace record.
1236 */
1237 error = xfs_alloc_get_rec(bno_cur, &fbno, &flen, &i);
1238 if (error)
1239 goto error0;
1240 if (XFS_IS_CORRUPT(args->mp, i != 1)) {
1241 error = -EFSCORRUPTED;
1242 goto error0;
1243 }
1244 ASSERT(fbno <= args->agbno);
1245
1246 /*
1247 * Check for overlapping busy extents.
1248 */
1249 tbno = fbno;
1250 tlen = flen;
1251 xfs_extent_busy_trim(args, &tbno, &tlen, &busy_gen);
1252
1253 /*
1254 * Give up if the start of the extent is busy, or the freespace isn't
1255 * long enough for the minimum request.
1256 */
1257 if (tbno > args->agbno)
1258 goto not_found;
1259 if (tlen < args->minlen)
1260 goto not_found;
1261 tend = tbno + tlen;
1262 if (tend < args->agbno + args->minlen)
1263 goto not_found;
1264
1265 /*
1266 * End of extent will be smaller of the freespace end and the
1267 * maximal requested end.
1268 *
1269 * Fix the length according to mod and prod if given.
1270 */
1271 args->len = XFS_AGBLOCK_MIN(tend, args->agbno + args->maxlen)
1272 - args->agbno;
1273 xfs_alloc_fix_len(args);
1274 ASSERT(args->agbno + args->len <= tend);
1275
1276 /*
1277 * We are allocating agbno for args->len
1278 * Allocate/initialize a cursor for the by-size btree.
1279 */
1280 cnt_cur = xfs_allocbt_init_cursor(args->mp, args->tp, args->agbp,
1281 args->agno, XFS_BTNUM_CNT);
1282 ASSERT(args->agbno + args->len <= be32_to_cpu(agf->agf_length));
1283 error = xfs_alloc_fixup_trees(cnt_cur, bno_cur, fbno, flen, args->agbno,
1284 args->len, XFSA_FIXUP_BNO_OK);
1285 if (error) {
1286 xfs_btree_del_cursor(cnt_cur, XFS_BTREE_ERROR);
1287 goto error0;
1288 }
1289
1290 xfs_btree_del_cursor(bno_cur, XFS_BTREE_NOERROR);
1291 xfs_btree_del_cursor(cnt_cur, XFS_BTREE_NOERROR);
1292
1293 args->wasfromfl = 0;
1294 trace_xfs_alloc_exact_done(args);
1295 return 0;
1296
1297not_found:
1298 /* Didn't find it, return null. */
1299 xfs_btree_del_cursor(bno_cur, XFS_BTREE_NOERROR);
1300 args->agbno = NULLAGBLOCK;
1301 trace_xfs_alloc_exact_notfound(args);
1302 return 0;
1303
1304error0:
1305 xfs_btree_del_cursor(bno_cur, XFS_BTREE_ERROR);
1306 trace_xfs_alloc_exact_error(args);
1307 return error;
1308}
1309
1310/*
1311 * Search a given number of btree records in a given direction. Check each
1312 * record against the good extent we've already found.
1313 */
1314STATIC int
1315xfs_alloc_walk_iter(
1316 struct xfs_alloc_arg *args,
1317 struct xfs_alloc_cur *acur,
1318 struct xfs_btree_cur *cur,
1319 bool increment,
1320 bool find_one, /* quit on first candidate */
1321 int count, /* rec count (-1 for infinite) */
1322 int *stat)
1323{
1324 int error;
1325 int i;
1326
1327 *stat = 0;
1328
1329 /*
1330 * Search so long as the cursor is active or we find a better extent.
1331 * The cursor is deactivated if it extends beyond the range of the
1332 * current allocation candidate.
1333 */
1334 while (xfs_alloc_cur_active(cur) && count) {
1335 error = xfs_alloc_cur_check(args, acur, cur, &i);
1336 if (error)
1337 return error;
1338 if (i == 1) {
1339 *stat = 1;
1340 if (find_one)
1341 break;
1342 }
1343 if (!xfs_alloc_cur_active(cur))
1344 break;
1345
1346 if (increment)
1347 error = xfs_btree_increment(cur, 0, &i);
1348 else
1349 error = xfs_btree_decrement(cur, 0, &i);
1350 if (error)
1351 return error;
1352 if (i == 0)
1353 cur->bc_ag.abt.active = false;
1354
1355 if (count > 0)
1356 count--;
1357 }
1358
1359 return 0;
1360}
1361
1362/*
1363 * Search the by-bno and by-size btrees in parallel in search of an extent with
1364 * ideal locality based on the NEAR mode ->agbno locality hint.
1365 */
1366STATIC int
1367xfs_alloc_ag_vextent_locality(
1368 struct xfs_alloc_arg *args,
1369 struct xfs_alloc_cur *acur,
1370 int *stat)
1371{
1372 struct xfs_btree_cur *fbcur = NULL;
1373 int error;
1374 int i;
1375 bool fbinc;
1376
1377 ASSERT(acur->len == 0);
1378 ASSERT(args->type == XFS_ALLOCTYPE_NEAR_BNO);
1379
1380 *stat = 0;
1381
1382 error = xfs_alloc_lookup_ge(acur->cnt, args->agbno, acur->cur_len, &i);
1383 if (error)
1384 return error;
1385 error = xfs_alloc_lookup_le(acur->bnolt, args->agbno, 0, &i);
1386 if (error)
1387 return error;
1388 error = xfs_alloc_lookup_ge(acur->bnogt, args->agbno, 0, &i);
1389 if (error)
1390 return error;
1391
1392 /*
1393 * Search the bnobt and cntbt in parallel. Search the bnobt left and
1394 * right and lookup the closest extent to the locality hint for each
1395 * extent size key in the cntbt. The entire search terminates
1396 * immediately on a bnobt hit because that means we've found best case
1397 * locality. Otherwise the search continues until the cntbt cursor runs
1398 * off the end of the tree. If no allocation candidate is found at this
1399 * point, give up on locality, walk backwards from the end of the cntbt
1400 * and take the first available extent.
1401 *
1402 * The parallel tree searches balance each other out to provide fairly
1403 * consistent performance for various situations. The bnobt search can
1404 * have pathological behavior in the worst case scenario of larger
1405 * allocation requests and fragmented free space. On the other hand, the
1406 * bnobt is able to satisfy most smaller allocation requests much more
1407 * quickly than the cntbt. The cntbt search can sift through fragmented
1408 * free space and sets of free extents for larger allocation requests
1409 * more quickly than the bnobt. Since the locality hint is just a hint
1410 * and we don't want to scan the entire bnobt for perfect locality, the
1411 * cntbt search essentially bounds the bnobt search such that we can
1412 * find good enough locality at reasonable performance in most cases.
1413 */
1414 while (xfs_alloc_cur_active(acur->bnolt) ||
1415 xfs_alloc_cur_active(acur->bnogt) ||
1416 xfs_alloc_cur_active(acur->cnt)) {
1417
1418 trace_xfs_alloc_cur_lookup(args);
1419
1420 /*
1421 * Search the bnobt left and right. In the case of a hit, finish
1422 * the search in the opposite direction and we're done.
1423 */
1424 error = xfs_alloc_walk_iter(args, acur, acur->bnolt, false,
1425 true, 1, &i);
1426 if (error)
1427 return error;
1428 if (i == 1) {
1429 trace_xfs_alloc_cur_left(args);
1430 fbcur = acur->bnogt;
1431 fbinc = true;
1432 break;
1433 }
1434 error = xfs_alloc_walk_iter(args, acur, acur->bnogt, true, true,
1435 1, &i);
1436 if (error)
1437 return error;
1438 if (i == 1) {
1439 trace_xfs_alloc_cur_right(args);
1440 fbcur = acur->bnolt;
1441 fbinc = false;
1442 break;
1443 }
1444
1445 /*
1446 * Check the extent with best locality based on the current
1447 * extent size search key and keep track of the best candidate.
1448 */
1449 error = xfs_alloc_cntbt_iter(args, acur);
1450 if (error)
1451 return error;
1452 if (!xfs_alloc_cur_active(acur->cnt)) {
1453 trace_xfs_alloc_cur_lookup_done(args);
1454 break;
1455 }
1456 }
1457
1458 /*
1459 * If we failed to find anything due to busy extents, return empty
1460 * handed so the caller can flush and retry. If no busy extents were
1461 * found, walk backwards from the end of the cntbt as a last resort.
1462 */
1463 if (!xfs_alloc_cur_active(acur->cnt) && !acur->len && !acur->busy) {
1464 error = xfs_btree_decrement(acur->cnt, 0, &i);
1465 if (error)
1466 return error;
1467 if (i) {
1468 acur->cnt->bc_ag.abt.active = true;
1469 fbcur = acur->cnt;
1470 fbinc = false;
1471 }
1472 }
1473
1474 /*
1475 * Search in the opposite direction for a better entry in the case of
1476 * a bnobt hit or walk backwards from the end of the cntbt.
1477 */
1478 if (fbcur) {
1479 error = xfs_alloc_walk_iter(args, acur, fbcur, fbinc, true, -1,
1480 &i);
1481 if (error)
1482 return error;
1483 }
1484
1485 if (acur->len)
1486 *stat = 1;
1487
1488 return 0;
1489}
1490
1491/* Check the last block of the cnt btree for allocations. */
1492static int
1493xfs_alloc_ag_vextent_lastblock(
1494 struct xfs_alloc_arg *args,
1495 struct xfs_alloc_cur *acur,
1496 xfs_agblock_t *bno,
1497 xfs_extlen_t *len,
1498 bool *allocated)
1499{
1500 int error;
1501 int i;
1502
1503#ifdef DEBUG
1504 /* Randomly don't execute the first algorithm. */
1505 if (prandom_u32() & 1)
1506 return 0;
1507#endif
1508
1509 /*
1510 * Start from the entry that lookup found, sequence through all larger
1511 * free blocks. If we're actually pointing at a record smaller than
1512 * maxlen, go to the start of this block, and skip all those smaller
1513 * than minlen.
1514 */
1515 if (*len || args->alignment > 1) {
1516 acur->cnt->bc_ptrs[0] = 1;
1517 do {
1518 error = xfs_alloc_get_rec(acur->cnt, bno, len, &i);
1519 if (error)
1520 return error;
1521 if (XFS_IS_CORRUPT(args->mp, i != 1))
1522 return -EFSCORRUPTED;
1523 if (*len >= args->minlen)
1524 break;
1525 error = xfs_btree_increment(acur->cnt, 0, &i);
1526 if (error)
1527 return error;
1528 } while (i);
1529 ASSERT(*len >= args->minlen);
1530 if (!i)
1531 return 0;
1532 }
1533
1534 error = xfs_alloc_walk_iter(args, acur, acur->cnt, true, false, -1, &i);
1535 if (error)
1536 return error;
1537
1538 /*
1539 * It didn't work. We COULD be in a case where there's a good record
1540 * somewhere, so try again.
1541 */
1542 if (acur->len == 0)
1543 return 0;
1544
1545 trace_xfs_alloc_near_first(args);
1546 *allocated = true;
1547 return 0;
1548}
1549
1550/*
1551 * Allocate a variable extent near bno in the allocation group agno.
1552 * Extent's length (returned in len) will be between minlen and maxlen,
1553 * and of the form k * prod + mod unless there's nothing that large.
1554 * Return the starting a.g. block, or NULLAGBLOCK if we can't do it.
1555 */
1556STATIC int
1557xfs_alloc_ag_vextent_near(
1558 struct xfs_alloc_arg *args)
1559{
1560 struct xfs_alloc_cur acur = {};
1561 int error; /* error code */
1562 int i; /* result code, temporary */
1563 xfs_agblock_t bno;
1564 xfs_extlen_t len;
1565
1566 /* handle uninitialized agbno range so caller doesn't have to */
1567 if (!args->min_agbno && !args->max_agbno)
1568 args->max_agbno = args->mp->m_sb.sb_agblocks - 1;
1569 ASSERT(args->min_agbno <= args->max_agbno);
1570
1571 /* clamp agbno to the range if it's outside */
1572 if (args->agbno < args->min_agbno)
1573 args->agbno = args->min_agbno;
1574 if (args->agbno > args->max_agbno)
1575 args->agbno = args->max_agbno;
1576
1577restart:
1578 len = 0;
1579
1580 /*
1581 * Set up cursors and see if there are any free extents as big as
1582 * maxlen. If not, pick the last entry in the tree unless the tree is
1583 * empty.
1584 */
1585 error = xfs_alloc_cur_setup(args, &acur);
1586 if (error == -ENOSPC) {
1587 error = xfs_alloc_ag_vextent_small(args, acur.cnt, &bno,
1588 &len, &i);
1589 if (error)
1590 goto out;
1591 if (i == 0 || len == 0) {
1592 trace_xfs_alloc_near_noentry(args);
1593 goto out;
1594 }
1595 ASSERT(i == 1);
1596 } else if (error) {
1597 goto out;
1598 }
1599
1600 /*
1601 * First algorithm.
1602 * If the requested extent is large wrt the freespaces available
1603 * in this a.g., then the cursor will be pointing to a btree entry
1604 * near the right edge of the tree. If it's in the last btree leaf
1605 * block, then we just examine all the entries in that block
1606 * that are big enough, and pick the best one.
1607 */
1608 if (xfs_btree_islastblock(acur.cnt, 0)) {
1609 bool allocated = false;
1610
1611 error = xfs_alloc_ag_vextent_lastblock(args, &acur, &bno, &len,
1612 &allocated);
1613 if (error)
1614 goto out;
1615 if (allocated)
1616 goto alloc_finish;
1617 }
1618
1619 /*
1620 * Second algorithm. Combined cntbt and bnobt search to find ideal
1621 * locality.
1622 */
1623 error = xfs_alloc_ag_vextent_locality(args, &acur, &i);
1624 if (error)
1625 goto out;
1626
1627 /*
1628 * If we couldn't get anything, give up.
1629 */
1630 if (!acur.len) {
1631 if (acur.busy) {
1632 trace_xfs_alloc_near_busy(args);
1633 xfs_extent_busy_flush(args->mp, args->pag,
1634 acur.busy_gen);
1635 goto restart;
1636 }
1637 trace_xfs_alloc_size_neither(args);
1638 args->agbno = NULLAGBLOCK;
1639 goto out;
1640 }
1641
1642alloc_finish:
1643 /* fix up btrees on a successful allocation */
1644 error = xfs_alloc_cur_finish(args, &acur);
1645
1646out:
1647 xfs_alloc_cur_close(&acur, error);
1648 return error;
1649}
1650
1651/*
1652 * Allocate a variable extent anywhere in the allocation group agno.
1653 * Extent's length (returned in len) will be between minlen and maxlen,
1654 * and of the form k * prod + mod unless there's nothing that large.
1655 * Return the starting a.g. block, or NULLAGBLOCK if we can't do it.
1656 */
1657STATIC int /* error */
1658xfs_alloc_ag_vextent_size(
1659 xfs_alloc_arg_t *args) /* allocation argument structure */
1660{
1661 struct xfs_agf *agf = args->agbp->b_addr;
1662 xfs_btree_cur_t *bno_cur; /* cursor for bno btree */
1663 xfs_btree_cur_t *cnt_cur; /* cursor for cnt btree */
1664 int error; /* error result */
1665 xfs_agblock_t fbno; /* start of found freespace */
1666 xfs_extlen_t flen; /* length of found freespace */
1667 int i; /* temp status variable */
1668 xfs_agblock_t rbno; /* returned block number */
1669 xfs_extlen_t rlen; /* length of returned extent */
1670 bool busy;
1671 unsigned busy_gen;
1672
1673restart:
1674 /*
1675 * Allocate and initialize a cursor for the by-size btree.
1676 */
1677 cnt_cur = xfs_allocbt_init_cursor(args->mp, args->tp, args->agbp,
1678 args->agno, XFS_BTNUM_CNT);
1679 bno_cur = NULL;
1680 busy = false;
1681
1682 /*
1683 * Look for an entry >= maxlen+alignment-1 blocks.
1684 */
1685 if ((error = xfs_alloc_lookup_ge(cnt_cur, 0,
1686 args->maxlen + args->alignment - 1, &i)))
1687 goto error0;
1688
1689 /*
1690 * If none then we have to settle for a smaller extent. In the case that
1691 * there are no large extents, this will return the last entry in the
1692 * tree unless the tree is empty. In the case that there are only busy
1693 * large extents, this will return the largest small extent unless there
1694 * are no smaller extents available.
1695 */
1696 if (!i) {
1697 error = xfs_alloc_ag_vextent_small(args, cnt_cur,
1698 &fbno, &flen, &i);
1699 if (error)
1700 goto error0;
1701 if (i == 0 || flen == 0) {
1702 xfs_btree_del_cursor(cnt_cur, XFS_BTREE_NOERROR);
1703 trace_xfs_alloc_size_noentry(args);
1704 return 0;
1705 }
1706 ASSERT(i == 1);
1707 busy = xfs_alloc_compute_aligned(args, fbno, flen, &rbno,
1708 &rlen, &busy_gen);
1709 } else {
1710 /*
1711 * Search for a non-busy extent that is large enough.
1712 */
1713 for (;;) {
1714 error = xfs_alloc_get_rec(cnt_cur, &fbno, &flen, &i);
1715 if (error)
1716 goto error0;
1717 if (XFS_IS_CORRUPT(args->mp, i != 1)) {
1718 error = -EFSCORRUPTED;
1719 goto error0;
1720 }
1721
1722 busy = xfs_alloc_compute_aligned(args, fbno, flen,
1723 &rbno, &rlen, &busy_gen);
1724
1725 if (rlen >= args->maxlen)
1726 break;
1727
1728 error = xfs_btree_increment(cnt_cur, 0, &i);
1729 if (error)
1730 goto error0;
1731 if (i == 0) {
1732 /*
1733 * Our only valid extents must have been busy.
1734 * Make it unbusy by forcing the log out and
1735 * retrying.
1736 */
1737 xfs_btree_del_cursor(cnt_cur,
1738 XFS_BTREE_NOERROR);
1739 trace_xfs_alloc_size_busy(args);
1740 xfs_extent_busy_flush(args->mp,
1741 args->pag, busy_gen);
1742 goto restart;
1743 }
1744 }
1745 }
1746
1747 /*
1748 * In the first case above, we got the last entry in the
1749 * by-size btree. Now we check to see if the space hits maxlen
1750 * once aligned; if not, we search left for something better.
1751 * This can't happen in the second case above.
1752 */
1753 rlen = XFS_EXTLEN_MIN(args->maxlen, rlen);
1754 if (XFS_IS_CORRUPT(args->mp,
1755 rlen != 0 &&
1756 (rlen > flen ||
1757 rbno + rlen > fbno + flen))) {
1758 error = -EFSCORRUPTED;
1759 goto error0;
1760 }
1761 if (rlen < args->maxlen) {
1762 xfs_agblock_t bestfbno;
1763 xfs_extlen_t bestflen;
1764 xfs_agblock_t bestrbno;
1765 xfs_extlen_t bestrlen;
1766
1767 bestrlen = rlen;
1768 bestrbno = rbno;
1769 bestflen = flen;
1770 bestfbno = fbno;
1771 for (;;) {
1772 if ((error = xfs_btree_decrement(cnt_cur, 0, &i)))
1773 goto error0;
1774 if (i == 0)
1775 break;
1776 if ((error = xfs_alloc_get_rec(cnt_cur, &fbno, &flen,
1777 &i)))
1778 goto error0;
1779 if (XFS_IS_CORRUPT(args->mp, i != 1)) {
1780 error = -EFSCORRUPTED;
1781 goto error0;
1782 }
1783 if (flen < bestrlen)
1784 break;
1785 busy = xfs_alloc_compute_aligned(args, fbno, flen,
1786 &rbno, &rlen, &busy_gen);
1787 rlen = XFS_EXTLEN_MIN(args->maxlen, rlen);
1788 if (XFS_IS_CORRUPT(args->mp,
1789 rlen != 0 &&
1790 (rlen > flen ||
1791 rbno + rlen > fbno + flen))) {
1792 error = -EFSCORRUPTED;
1793 goto error0;
1794 }
1795 if (rlen > bestrlen) {
1796 bestrlen = rlen;
1797 bestrbno = rbno;
1798 bestflen = flen;
1799 bestfbno = fbno;
1800 if (rlen == args->maxlen)
1801 break;
1802 }
1803 }
1804 if ((error = xfs_alloc_lookup_eq(cnt_cur, bestfbno, bestflen,
1805 &i)))
1806 goto error0;
1807 if (XFS_IS_CORRUPT(args->mp, i != 1)) {
1808 error = -EFSCORRUPTED;
1809 goto error0;
1810 }
1811 rlen = bestrlen;
1812 rbno = bestrbno;
1813 flen = bestflen;
1814 fbno = bestfbno;
1815 }
1816 args->wasfromfl = 0;
1817 /*
1818 * Fix up the length.
1819 */
1820 args->len = rlen;
1821 if (rlen < args->minlen) {
1822 if (busy) {
1823 xfs_btree_del_cursor(cnt_cur, XFS_BTREE_NOERROR);
1824 trace_xfs_alloc_size_busy(args);
1825 xfs_extent_busy_flush(args->mp, args->pag, busy_gen);
1826 goto restart;
1827 }
1828 goto out_nominleft;
1829 }
1830 xfs_alloc_fix_len(args);
1831
1832 rlen = args->len;
1833 if (XFS_IS_CORRUPT(args->mp, rlen > flen)) {
1834 error = -EFSCORRUPTED;
1835 goto error0;
1836 }
1837 /*
1838 * Allocate and initialize a cursor for the by-block tree.
1839 */
1840 bno_cur = xfs_allocbt_init_cursor(args->mp, args->tp, args->agbp,
1841 args->agno, XFS_BTNUM_BNO);
1842 if ((error = xfs_alloc_fixup_trees(cnt_cur, bno_cur, fbno, flen,
1843 rbno, rlen, XFSA_FIXUP_CNT_OK)))
1844 goto error0;
1845 xfs_btree_del_cursor(cnt_cur, XFS_BTREE_NOERROR);
1846 xfs_btree_del_cursor(bno_cur, XFS_BTREE_NOERROR);
1847 cnt_cur = bno_cur = NULL;
1848 args->len = rlen;
1849 args->agbno = rbno;
1850 if (XFS_IS_CORRUPT(args->mp,
1851 args->agbno + args->len >
1852 be32_to_cpu(agf->agf_length))) {
1853 error = -EFSCORRUPTED;
1854 goto error0;
1855 }
1856 trace_xfs_alloc_size_done(args);
1857 return 0;
1858
1859error0:
1860 trace_xfs_alloc_size_error(args);
1861 if (cnt_cur)
1862 xfs_btree_del_cursor(cnt_cur, XFS_BTREE_ERROR);
1863 if (bno_cur)
1864 xfs_btree_del_cursor(bno_cur, XFS_BTREE_ERROR);
1865 return error;
1866
1867out_nominleft:
1868 xfs_btree_del_cursor(cnt_cur, XFS_BTREE_NOERROR);
1869 trace_xfs_alloc_size_nominleft(args);
1870 args->agbno = NULLAGBLOCK;
1871 return 0;
1872}
1873
1874/*
1875 * Free the extent starting at agno/bno for length.
1876 */
1877STATIC int
1878xfs_free_ag_extent(
1879 struct xfs_trans *tp,
1880 struct xfs_buf *agbp,
1881 xfs_agnumber_t agno,
1882 xfs_agblock_t bno,
1883 xfs_extlen_t len,
1884 const struct xfs_owner_info *oinfo,
1885 enum xfs_ag_resv_type type)
1886{
1887 struct xfs_mount *mp;
1888 struct xfs_btree_cur *bno_cur;
1889 struct xfs_btree_cur *cnt_cur;
1890 xfs_agblock_t gtbno; /* start of right neighbor */
1891 xfs_extlen_t gtlen; /* length of right neighbor */
1892 xfs_agblock_t ltbno; /* start of left neighbor */
1893 xfs_extlen_t ltlen; /* length of left neighbor */
1894 xfs_agblock_t nbno; /* new starting block of freesp */
1895 xfs_extlen_t nlen; /* new length of freespace */
1896 int haveleft; /* have a left neighbor */
1897 int haveright; /* have a right neighbor */
1898 int i;
1899 int error;
1900
1901 bno_cur = cnt_cur = NULL;
1902 mp = tp->t_mountp;
1903
1904 if (!xfs_rmap_should_skip_owner_update(oinfo)) {
1905 error = xfs_rmap_free(tp, agbp, agno, bno, len, oinfo);
1906 if (error)
1907 goto error0;
1908 }
1909
1910 /*
1911 * Allocate and initialize a cursor for the by-block btree.
1912 */
1913 bno_cur = xfs_allocbt_init_cursor(mp, tp, agbp, agno, XFS_BTNUM_BNO);
1914 /*
1915 * Look for a neighboring block on the left (lower block numbers)
1916 * that is contiguous with this space.
1917 */
1918 if ((error = xfs_alloc_lookup_le(bno_cur, bno, len, &haveleft)))
1919 goto error0;
1920 if (haveleft) {
1921 /*
1922 * There is a block to our left.
1923 */
1924 if ((error = xfs_alloc_get_rec(bno_cur, <bno, <len, &i)))
1925 goto error0;
1926 if (XFS_IS_CORRUPT(mp, i != 1)) {
1927 error = -EFSCORRUPTED;
1928 goto error0;
1929 }
1930 /*
1931 * It's not contiguous, though.
1932 */
1933 if (ltbno + ltlen < bno)
1934 haveleft = 0;
1935 else {
1936 /*
1937 * If this failure happens the request to free this
1938 * space was invalid, it's (partly) already free.
1939 * Very bad.
1940 */
1941 if (XFS_IS_CORRUPT(mp, ltbno + ltlen > bno)) {
1942 error = -EFSCORRUPTED;
1943 goto error0;
1944 }
1945 }
1946 }
1947 /*
1948 * Look for a neighboring block on the right (higher block numbers)
1949 * that is contiguous with this space.
1950 */
1951 if ((error = xfs_btree_increment(bno_cur, 0, &haveright)))
1952 goto error0;
1953 if (haveright) {
1954 /*
1955 * There is a block to our right.
1956 */
1957 if ((error = xfs_alloc_get_rec(bno_cur, >bno, >len, &i)))
1958 goto error0;
1959 if (XFS_IS_CORRUPT(mp, i != 1)) {
1960 error = -EFSCORRUPTED;
1961 goto error0;
1962 }
1963 /*
1964 * It's not contiguous, though.
1965 */
1966 if (bno + len < gtbno)
1967 haveright = 0;
1968 else {
1969 /*
1970 * If this failure happens the request to free this
1971 * space was invalid, it's (partly) already free.
1972 * Very bad.
1973 */
1974 if (XFS_IS_CORRUPT(mp, bno + len > gtbno)) {
1975 error = -EFSCORRUPTED;
1976 goto error0;
1977 }
1978 }
1979 }
1980 /*
1981 * Now allocate and initialize a cursor for the by-size tree.
1982 */
1983 cnt_cur = xfs_allocbt_init_cursor(mp, tp, agbp, agno, XFS_BTNUM_CNT);
1984 /*
1985 * Have both left and right contiguous neighbors.
1986 * Merge all three into a single free block.
1987 */
1988 if (haveleft && haveright) {
1989 /*
1990 * Delete the old by-size entry on the left.
1991 */
1992 if ((error = xfs_alloc_lookup_eq(cnt_cur, ltbno, ltlen, &i)))
1993 goto error0;
1994 if (XFS_IS_CORRUPT(mp, i != 1)) {
1995 error = -EFSCORRUPTED;
1996 goto error0;
1997 }
1998 if ((error = xfs_btree_delete(cnt_cur, &i)))
1999 goto error0;
2000 if (XFS_IS_CORRUPT(mp, i != 1)) {
2001 error = -EFSCORRUPTED;
2002 goto error0;
2003 }
2004 /*
2005 * Delete the old by-size entry on the right.
2006 */
2007 if ((error = xfs_alloc_lookup_eq(cnt_cur, gtbno, gtlen, &i)))
2008 goto error0;
2009 if (XFS_IS_CORRUPT(mp, i != 1)) {
2010 error = -EFSCORRUPTED;
2011 goto error0;
2012 }
2013 if ((error = xfs_btree_delete(cnt_cur, &i)))
2014 goto error0;
2015 if (XFS_IS_CORRUPT(mp, i != 1)) {
2016 error = -EFSCORRUPTED;
2017 goto error0;
2018 }
2019 /*
2020 * Delete the old by-block entry for the right block.
2021 */
2022 if ((error = xfs_btree_delete(bno_cur, &i)))
2023 goto error0;
2024 if (XFS_IS_CORRUPT(mp, i != 1)) {
2025 error = -EFSCORRUPTED;
2026 goto error0;
2027 }
2028 /*
2029 * Move the by-block cursor back to the left neighbor.
2030 */
2031 if ((error = xfs_btree_decrement(bno_cur, 0, &i)))
2032 goto error0;
2033 if (XFS_IS_CORRUPT(mp, i != 1)) {
2034 error = -EFSCORRUPTED;
2035 goto error0;
2036 }
2037#ifdef DEBUG
2038 /*
2039 * Check that this is the right record: delete didn't
2040 * mangle the cursor.
2041 */
2042 {
2043 xfs_agblock_t xxbno;
2044 xfs_extlen_t xxlen;
2045
2046 if ((error = xfs_alloc_get_rec(bno_cur, &xxbno, &xxlen,
2047 &i)))
2048 goto error0;
2049 if (XFS_IS_CORRUPT(mp,
2050 i != 1 ||
2051 xxbno != ltbno ||
2052 xxlen != ltlen)) {
2053 error = -EFSCORRUPTED;
2054 goto error0;
2055 }
2056 }
2057#endif
2058 /*
2059 * Update remaining by-block entry to the new, joined block.
2060 */
2061 nbno = ltbno;
2062 nlen = len + ltlen + gtlen;
2063 if ((error = xfs_alloc_update(bno_cur, nbno, nlen)))
2064 goto error0;
2065 }
2066 /*
2067 * Have only a left contiguous neighbor.
2068 * Merge it together with the new freespace.
2069 */
2070 else if (haveleft) {
2071 /*
2072 * Delete the old by-size entry on the left.
2073 */
2074 if ((error = xfs_alloc_lookup_eq(cnt_cur, ltbno, ltlen, &i)))
2075 goto error0;
2076 if (XFS_IS_CORRUPT(mp, i != 1)) {
2077 error = -EFSCORRUPTED;
2078 goto error0;
2079 }
2080 if ((error = xfs_btree_delete(cnt_cur, &i)))
2081 goto error0;
2082 if (XFS_IS_CORRUPT(mp, i != 1)) {
2083 error = -EFSCORRUPTED;
2084 goto error0;
2085 }
2086 /*
2087 * Back up the by-block cursor to the left neighbor, and
2088 * update its length.
2089 */
2090 if ((error = xfs_btree_decrement(bno_cur, 0, &i)))
2091 goto error0;
2092 if (XFS_IS_CORRUPT(mp, i != 1)) {
2093 error = -EFSCORRUPTED;
2094 goto error0;
2095 }
2096 nbno = ltbno;
2097 nlen = len + ltlen;
2098 if ((error = xfs_alloc_update(bno_cur, nbno, nlen)))
2099 goto error0;
2100 }
2101 /*
2102 * Have only a right contiguous neighbor.
2103 * Merge it together with the new freespace.
2104 */
2105 else if (haveright) {
2106 /*
2107 * Delete the old by-size entry on the right.
2108 */
2109 if ((error = xfs_alloc_lookup_eq(cnt_cur, gtbno, gtlen, &i)))
2110 goto error0;
2111 if (XFS_IS_CORRUPT(mp, i != 1)) {
2112 error = -EFSCORRUPTED;
2113 goto error0;
2114 }
2115 if ((error = xfs_btree_delete(cnt_cur, &i)))
2116 goto error0;
2117 if (XFS_IS_CORRUPT(mp, i != 1)) {
2118 error = -EFSCORRUPTED;
2119 goto error0;
2120 }
2121 /*
2122 * Update the starting block and length of the right
2123 * neighbor in the by-block tree.
2124 */
2125 nbno = bno;
2126 nlen = len + gtlen;
2127 if ((error = xfs_alloc_update(bno_cur, nbno, nlen)))
2128 goto error0;
2129 }
2130 /*
2131 * No contiguous neighbors.
2132 * Insert the new freespace into the by-block tree.
2133 */
2134 else {
2135 nbno = bno;
2136 nlen = len;
2137 if ((error = xfs_btree_insert(bno_cur, &i)))
2138 goto error0;
2139 if (XFS_IS_CORRUPT(mp, i != 1)) {
2140 error = -EFSCORRUPTED;
2141 goto error0;
2142 }
2143 }
2144 xfs_btree_del_cursor(bno_cur, XFS_BTREE_NOERROR);
2145 bno_cur = NULL;
2146 /*
2147 * In all cases we need to insert the new freespace in the by-size tree.
2148 */
2149 if ((error = xfs_alloc_lookup_eq(cnt_cur, nbno, nlen, &i)))
2150 goto error0;
2151 if (XFS_IS_CORRUPT(mp, i != 0)) {
2152 error = -EFSCORRUPTED;
2153 goto error0;
2154 }
2155 if ((error = xfs_btree_insert(cnt_cur, &i)))
2156 goto error0;
2157 if (XFS_IS_CORRUPT(mp, i != 1)) {
2158 error = -EFSCORRUPTED;
2159 goto error0;
2160 }
2161 xfs_btree_del_cursor(cnt_cur, XFS_BTREE_NOERROR);
2162 cnt_cur = NULL;
2163
2164 /*
2165 * Update the freespace totals in the ag and superblock.
2166 */
2167 error = xfs_alloc_update_counters(tp, agbp, len);
2168 xfs_ag_resv_free_extent(agbp->b_pag, type, tp, len);
2169 if (error)
2170 goto error0;
2171
2172 XFS_STATS_INC(mp, xs_freex);
2173 XFS_STATS_ADD(mp, xs_freeb, len);
2174
2175 trace_xfs_free_extent(mp, agno, bno, len, type, haveleft, haveright);
2176
2177 return 0;
2178
2179 error0:
2180 trace_xfs_free_extent(mp, agno, bno, len, type, -1, -1);
2181 if (bno_cur)
2182 xfs_btree_del_cursor(bno_cur, XFS_BTREE_ERROR);
2183 if (cnt_cur)
2184 xfs_btree_del_cursor(cnt_cur, XFS_BTREE_ERROR);
2185 return error;
2186}
2187
2188/*
2189 * Visible (exported) allocation/free functions.
2190 * Some of these are used just by xfs_alloc_btree.c and this file.
2191 */
2192
2193/*
2194 * Compute and fill in value of m_ag_maxlevels.
2195 */
2196void
2197xfs_alloc_compute_maxlevels(
2198 xfs_mount_t *mp) /* file system mount structure */
2199{
2200 mp->m_ag_maxlevels = xfs_btree_compute_maxlevels(mp->m_alloc_mnr,
2201 (mp->m_sb.sb_agblocks + 1) / 2);
2202}
2203
2204/*
2205 * Find the length of the longest extent in an AG. The 'need' parameter
2206 * specifies how much space we're going to need for the AGFL and the
2207 * 'reserved' parameter tells us how many blocks in this AG are reserved for
2208 * other callers.
2209 */
2210xfs_extlen_t
2211xfs_alloc_longest_free_extent(
2212 struct xfs_perag *pag,
2213 xfs_extlen_t need,
2214 xfs_extlen_t reserved)
2215{
2216 xfs_extlen_t delta = 0;
2217
2218 /*
2219 * If the AGFL needs a recharge, we'll have to subtract that from the
2220 * longest extent.
2221 */
2222 if (need > pag->pagf_flcount)
2223 delta = need - pag->pagf_flcount;
2224
2225 /*
2226 * If we cannot maintain others' reservations with space from the
2227 * not-longest freesp extents, we'll have to subtract /that/ from
2228 * the longest extent too.
2229 */
2230 if (pag->pagf_freeblks - pag->pagf_longest < reserved)
2231 delta += reserved - (pag->pagf_freeblks - pag->pagf_longest);
2232
2233 /*
2234 * If the longest extent is long enough to satisfy all the
2235 * reservations and AGFL rules in place, we can return this extent.
2236 */
2237 if (pag->pagf_longest > delta)
2238 return min_t(xfs_extlen_t, pag->pag_mount->m_ag_max_usable,
2239 pag->pagf_longest - delta);
2240
2241 /* Otherwise, let the caller try for 1 block if there's space. */
2242 return pag->pagf_flcount > 0 || pag->pagf_longest > 0;
2243}
2244
2245/*
2246 * Compute the minimum length of the AGFL in the given AG. If @pag is NULL,
2247 * return the largest possible minimum length.
2248 */
2249unsigned int
2250xfs_alloc_min_freelist(
2251 struct xfs_mount *mp,
2252 struct xfs_perag *pag)
2253{
2254 /* AG btrees have at least 1 level. */
2255 static const uint8_t fake_levels[XFS_BTNUM_AGF] = {1, 1, 1};
2256 const uint8_t *levels = pag ? pag->pagf_levels : fake_levels;
2257 unsigned int min_free;
2258
2259 ASSERT(mp->m_ag_maxlevels > 0);
2260
2261 /* space needed by-bno freespace btree */
2262 min_free = min_t(unsigned int, levels[XFS_BTNUM_BNOi] + 1,
2263 mp->m_ag_maxlevels);
2264 /* space needed by-size freespace btree */
2265 min_free += min_t(unsigned int, levels[XFS_BTNUM_CNTi] + 1,
2266 mp->m_ag_maxlevels);
2267 /* space needed reverse mapping used space btree */
2268 if (xfs_sb_version_hasrmapbt(&mp->m_sb))
2269 min_free += min_t(unsigned int, levels[XFS_BTNUM_RMAPi] + 1,
2270 mp->m_rmap_maxlevels);
2271
2272 return min_free;
2273}
2274
2275/*
2276 * Check if the operation we are fixing up the freelist for should go ahead or
2277 * not. If we are freeing blocks, we always allow it, otherwise the allocation
2278 * is dependent on whether the size and shape of free space available will
2279 * permit the requested allocation to take place.
2280 */
2281static bool
2282xfs_alloc_space_available(
2283 struct xfs_alloc_arg *args,
2284 xfs_extlen_t min_free,
2285 int flags)
2286{
2287 struct xfs_perag *pag = args->pag;
2288 xfs_extlen_t alloc_len, longest;
2289 xfs_extlen_t reservation; /* blocks that are still reserved */
2290 int available;
2291 xfs_extlen_t agflcount;
2292
2293 if (flags & XFS_ALLOC_FLAG_FREEING)
2294 return true;
2295
2296 reservation = xfs_ag_resv_needed(pag, args->resv);
2297
2298 /* do we have enough contiguous free space for the allocation? */
2299 alloc_len = args->minlen + (args->alignment - 1) + args->minalignslop;
2300 longest = xfs_alloc_longest_free_extent(pag, min_free, reservation);
2301 if (longest < alloc_len)
2302 return false;
2303
2304 /*
2305 * Do we have enough free space remaining for the allocation? Don't
2306 * account extra agfl blocks because we are about to defer free them,
2307 * making them unavailable until the current transaction commits.
2308 */
2309 agflcount = min_t(xfs_extlen_t, pag->pagf_flcount, min_free);
2310 available = (int)(pag->pagf_freeblks + agflcount -
2311 reservation - min_free - args->minleft);
2312 if (available < (int)max(args->total, alloc_len))
2313 return false;
2314
2315 /*
2316 * Clamp maxlen to the amount of free space available for the actual
2317 * extent allocation.
2318 */
2319 if (available < (int)args->maxlen && !(flags & XFS_ALLOC_FLAG_CHECK)) {
2320 args->maxlen = available;
2321 ASSERT(args->maxlen > 0);
2322 ASSERT(args->maxlen >= args->minlen);
2323 }
2324
2325 return true;
2326}
2327
2328int
2329xfs_free_agfl_block(
2330 struct xfs_trans *tp,
2331 xfs_agnumber_t agno,
2332 xfs_agblock_t agbno,
2333 struct xfs_buf *agbp,
2334 struct xfs_owner_info *oinfo)
2335{
2336 int error;
2337 struct xfs_buf *bp;
2338
2339 error = xfs_free_ag_extent(tp, agbp, agno, agbno, 1, oinfo,
2340 XFS_AG_RESV_AGFL);
2341 if (error)
2342 return error;
2343
2344 error = xfs_trans_get_buf(tp, tp->t_mountp->m_ddev_targp,
2345 XFS_AGB_TO_DADDR(tp->t_mountp, agno, agbno),
2346 tp->t_mountp->m_bsize, 0, &bp);
2347 if (error)
2348 return error;
2349 xfs_trans_binval(tp, bp);
2350
2351 return 0;
2352}
2353
2354/*
2355 * Check the agfl fields of the agf for inconsistency or corruption. The purpose
2356 * is to detect an agfl header padding mismatch between current and early v5
2357 * kernels. This problem manifests as a 1-slot size difference between the
2358 * on-disk flcount and the active [first, last] range of a wrapped agfl. This
2359 * may also catch variants of agfl count corruption unrelated to padding. Either
2360 * way, we'll reset the agfl and warn the user.
2361 *
2362 * Return true if a reset is required before the agfl can be used, false
2363 * otherwise.
2364 */
2365static bool
2366xfs_agfl_needs_reset(
2367 struct xfs_mount *mp,
2368 struct xfs_agf *agf)
2369{
2370 uint32_t f = be32_to_cpu(agf->agf_flfirst);
2371 uint32_t l = be32_to_cpu(agf->agf_fllast);
2372 uint32_t c = be32_to_cpu(agf->agf_flcount);
2373 int agfl_size = xfs_agfl_size(mp);
2374 int active;
2375
2376 /* no agfl header on v4 supers */
2377 if (!xfs_sb_version_hascrc(&mp->m_sb))
2378 return false;
2379
2380 /*
2381 * The agf read verifier catches severe corruption of these fields.
2382 * Repeat some sanity checks to cover a packed -> unpacked mismatch if
2383 * the verifier allows it.
2384 */
2385 if (f >= agfl_size || l >= agfl_size)
2386 return true;
2387 if (c > agfl_size)
2388 return true;
2389
2390 /*
2391 * Check consistency between the on-disk count and the active range. An
2392 * agfl padding mismatch manifests as an inconsistent flcount.
2393 */
2394 if (c && l >= f)
2395 active = l - f + 1;
2396 else if (c)
2397 active = agfl_size - f + l + 1;
2398 else
2399 active = 0;
2400
2401 return active != c;
2402}
2403
2404/*
2405 * Reset the agfl to an empty state. Ignore/drop any existing blocks since the
2406 * agfl content cannot be trusted. Warn the user that a repair is required to
2407 * recover leaked blocks.
2408 *
2409 * The purpose of this mechanism is to handle filesystems affected by the agfl
2410 * header padding mismatch problem. A reset keeps the filesystem online with a
2411 * relatively minor free space accounting inconsistency rather than suffer the
2412 * inevitable crash from use of an invalid agfl block.
2413 */
2414static void
2415xfs_agfl_reset(
2416 struct xfs_trans *tp,
2417 struct xfs_buf *agbp,
2418 struct xfs_perag *pag)
2419{
2420 struct xfs_mount *mp = tp->t_mountp;
2421 struct xfs_agf *agf = agbp->b_addr;
2422
2423 ASSERT(pag->pagf_agflreset);
2424 trace_xfs_agfl_reset(mp, agf, 0, _RET_IP_);
2425
2426 xfs_warn(mp,
2427 "WARNING: Reset corrupted AGFL on AG %u. %d blocks leaked. "
2428 "Please unmount and run xfs_repair.",
2429 pag->pag_agno, pag->pagf_flcount);
2430
2431 agf->agf_flfirst = 0;
2432 agf->agf_fllast = cpu_to_be32(xfs_agfl_size(mp) - 1);
2433 agf->agf_flcount = 0;
2434 xfs_alloc_log_agf(tp, agbp, XFS_AGF_FLFIRST | XFS_AGF_FLLAST |
2435 XFS_AGF_FLCOUNT);
2436
2437 pag->pagf_flcount = 0;
2438 pag->pagf_agflreset = false;
2439}
2440
2441/*
2442 * Defer an AGFL block free. This is effectively equivalent to
2443 * xfs_bmap_add_free() with some special handling particular to AGFL blocks.
2444 *
2445 * Deferring AGFL frees helps prevent log reservation overruns due to too many
2446 * allocation operations in a transaction. AGFL frees are prone to this problem
2447 * because for one they are always freed one at a time. Further, an immediate
2448 * AGFL block free can cause a btree join and require another block free before
2449 * the real allocation can proceed. Deferring the free disconnects freeing up
2450 * the AGFL slot from freeing the block.
2451 */
2452STATIC void
2453xfs_defer_agfl_block(
2454 struct xfs_trans *tp,
2455 xfs_agnumber_t agno,
2456 xfs_fsblock_t agbno,
2457 struct xfs_owner_info *oinfo)
2458{
2459 struct xfs_mount *mp = tp->t_mountp;
2460 struct xfs_extent_free_item *new; /* new element */
2461
2462 ASSERT(xfs_bmap_free_item_zone != NULL);
2463 ASSERT(oinfo != NULL);
2464
2465 new = kmem_cache_alloc(xfs_bmap_free_item_zone,
2466 GFP_KERNEL | __GFP_NOFAIL);
2467 new->xefi_startblock = XFS_AGB_TO_FSB(mp, agno, agbno);
2468 new->xefi_blockcount = 1;
2469 new->xefi_oinfo = *oinfo;
2470
2471 trace_xfs_agfl_free_defer(mp, agno, 0, agbno, 1);
2472
2473 xfs_defer_add(tp, XFS_DEFER_OPS_TYPE_AGFL_FREE, &new->xefi_list);
2474}
2475
2476/*
2477 * Decide whether to use this allocation group for this allocation.
2478 * If so, fix up the btree freelist's size.
2479 */
2480int /* error */
2481xfs_alloc_fix_freelist(
2482 struct xfs_alloc_arg *args, /* allocation argument structure */
2483 int flags) /* XFS_ALLOC_FLAG_... */
2484{
2485 struct xfs_mount *mp = args->mp;
2486 struct xfs_perag *pag = args->pag;
2487 struct xfs_trans *tp = args->tp;
2488 struct xfs_buf *agbp = NULL;
2489 struct xfs_buf *agflbp = NULL;
2490 struct xfs_alloc_arg targs; /* local allocation arguments */
2491 xfs_agblock_t bno; /* freelist block */
2492 xfs_extlen_t need; /* total blocks needed in freelist */
2493 int error = 0;
2494
2495 /* deferred ops (AGFL block frees) require permanent transactions */
2496 ASSERT(tp->t_flags & XFS_TRANS_PERM_LOG_RES);
2497
2498 if (!pag->pagf_init) {
2499 error = xfs_alloc_read_agf(mp, tp, args->agno, flags, &agbp);
2500 if (error) {
2501 /* Couldn't lock the AGF so skip this AG. */
2502 if (error == -EAGAIN)
2503 error = 0;
2504 goto out_no_agbp;
2505 }
2506 }
2507
2508 /*
2509 * If this is a metadata preferred pag and we are user data then try
2510 * somewhere else if we are not being asked to try harder at this
2511 * point
2512 */
2513 if (pag->pagf_metadata && (args->datatype & XFS_ALLOC_USERDATA) &&
2514 (flags & XFS_ALLOC_FLAG_TRYLOCK)) {
2515 ASSERT(!(flags & XFS_ALLOC_FLAG_FREEING));
2516 goto out_agbp_relse;
2517 }
2518
2519 need = xfs_alloc_min_freelist(mp, pag);
2520 if (!xfs_alloc_space_available(args, need, flags |
2521 XFS_ALLOC_FLAG_CHECK))
2522 goto out_agbp_relse;
2523
2524 /*
2525 * Get the a.g. freespace buffer.
2526 * Can fail if we're not blocking on locks, and it's held.
2527 */
2528 if (!agbp) {
2529 error = xfs_alloc_read_agf(mp, tp, args->agno, flags, &agbp);
2530 if (error) {
2531 /* Couldn't lock the AGF so skip this AG. */
2532 if (error == -EAGAIN)
2533 error = 0;
2534 goto out_no_agbp;
2535 }
2536 }
2537
2538 /* reset a padding mismatched agfl before final free space check */
2539 if (pag->pagf_agflreset)
2540 xfs_agfl_reset(tp, agbp, pag);
2541
2542 /* If there isn't enough total space or single-extent, reject it. */
2543 need = xfs_alloc_min_freelist(mp, pag);
2544 if (!xfs_alloc_space_available(args, need, flags))
2545 goto out_agbp_relse;
2546
2547 /*
2548 * Make the freelist shorter if it's too long.
2549 *
2550 * Note that from this point onwards, we will always release the agf and
2551 * agfl buffers on error. This handles the case where we error out and
2552 * the buffers are clean or may not have been joined to the transaction
2553 * and hence need to be released manually. If they have been joined to
2554 * the transaction, then xfs_trans_brelse() will handle them
2555 * appropriately based on the recursion count and dirty state of the
2556 * buffer.
2557 *
2558 * XXX (dgc): When we have lots of free space, does this buy us
2559 * anything other than extra overhead when we need to put more blocks
2560 * back on the free list? Maybe we should only do this when space is
2561 * getting low or the AGFL is more than half full?
2562 *
2563 * The NOSHRINK flag prevents the AGFL from being shrunk if it's too
2564 * big; the NORMAP flag prevents AGFL expand/shrink operations from
2565 * updating the rmapbt. Both flags are used in xfs_repair while we're
2566 * rebuilding the rmapbt, and neither are used by the kernel. They're
2567 * both required to ensure that rmaps are correctly recorded for the
2568 * regenerated AGFL, bnobt, and cntbt. See repair/phase5.c and
2569 * repair/rmap.c in xfsprogs for details.
2570 */
2571 memset(&targs, 0, sizeof(targs));
2572 /* struct copy below */
2573 if (flags & XFS_ALLOC_FLAG_NORMAP)
2574 targs.oinfo = XFS_RMAP_OINFO_SKIP_UPDATE;
2575 else
2576 targs.oinfo = XFS_RMAP_OINFO_AG;
2577 while (!(flags & XFS_ALLOC_FLAG_NOSHRINK) && pag->pagf_flcount > need) {
2578 error = xfs_alloc_get_freelist(tp, agbp, &bno, 0);
2579 if (error)
2580 goto out_agbp_relse;
2581
2582 /* defer agfl frees */
2583 xfs_defer_agfl_block(tp, args->agno, bno, &targs.oinfo);
2584 }
2585
2586 targs.tp = tp;
2587 targs.mp = mp;
2588 targs.agbp = agbp;
2589 targs.agno = args->agno;
2590 targs.alignment = targs.minlen = targs.prod = 1;
2591 targs.type = XFS_ALLOCTYPE_THIS_AG;
2592 targs.pag = pag;
2593 error = xfs_alloc_read_agfl(mp, tp, targs.agno, &agflbp);
2594 if (error)
2595 goto out_agbp_relse;
2596
2597 /* Make the freelist longer if it's too short. */
2598 while (pag->pagf_flcount < need) {
2599 targs.agbno = 0;
2600 targs.maxlen = need - pag->pagf_flcount;
2601 targs.resv = XFS_AG_RESV_AGFL;
2602
2603 /* Allocate as many blocks as possible at once. */
2604 error = xfs_alloc_ag_vextent(&targs);
2605 if (error)
2606 goto out_agflbp_relse;
2607
2608 /*
2609 * Stop if we run out. Won't happen if callers are obeying
2610 * the restrictions correctly. Can happen for free calls
2611 * on a completely full ag.
2612 */
2613 if (targs.agbno == NULLAGBLOCK) {
2614 if (flags & XFS_ALLOC_FLAG_FREEING)
2615 break;
2616 goto out_agflbp_relse;
2617 }
2618 /*
2619 * Put each allocated block on the list.
2620 */
2621 for (bno = targs.agbno; bno < targs.agbno + targs.len; bno++) {
2622 error = xfs_alloc_put_freelist(tp, agbp,
2623 agflbp, bno, 0);
2624 if (error)
2625 goto out_agflbp_relse;
2626 }
2627 }
2628 xfs_trans_brelse(tp, agflbp);
2629 args->agbp = agbp;
2630 return 0;
2631
2632out_agflbp_relse:
2633 xfs_trans_brelse(tp, agflbp);
2634out_agbp_relse:
2635 if (agbp)
2636 xfs_trans_brelse(tp, agbp);
2637out_no_agbp:
2638 args->agbp = NULL;
2639 return error;
2640}
2641
2642/*
2643 * Get a block from the freelist.
2644 * Returns with the buffer for the block gotten.
2645 */
2646int /* error */
2647xfs_alloc_get_freelist(
2648 xfs_trans_t *tp, /* transaction pointer */
2649 xfs_buf_t *agbp, /* buffer containing the agf structure */
2650 xfs_agblock_t *bnop, /* block address retrieved from freelist */
2651 int btreeblk) /* destination is a AGF btree */
2652{
2653 struct xfs_agf *agf = agbp->b_addr;
2654 xfs_buf_t *agflbp;/* buffer for a.g. freelist structure */
2655 xfs_agblock_t bno; /* block number returned */
2656 __be32 *agfl_bno;
2657 int error;
2658 int logflags;
2659 xfs_mount_t *mp = tp->t_mountp;
2660 xfs_perag_t *pag; /* per allocation group data */
2661
2662 /*
2663 * Freelist is empty, give up.
2664 */
2665 if (!agf->agf_flcount) {
2666 *bnop = NULLAGBLOCK;
2667 return 0;
2668 }
2669 /*
2670 * Read the array of free blocks.
2671 */
2672 error = xfs_alloc_read_agfl(mp, tp, be32_to_cpu(agf->agf_seqno),
2673 &agflbp);
2674 if (error)
2675 return error;
2676
2677
2678 /*
2679 * Get the block number and update the data structures.
2680 */
2681 agfl_bno = xfs_buf_to_agfl_bno(agflbp);
2682 bno = be32_to_cpu(agfl_bno[be32_to_cpu(agf->agf_flfirst)]);
2683 be32_add_cpu(&agf->agf_flfirst, 1);
2684 xfs_trans_brelse(tp, agflbp);
2685 if (be32_to_cpu(agf->agf_flfirst) == xfs_agfl_size(mp))
2686 agf->agf_flfirst = 0;
2687
2688 pag = agbp->b_pag;
2689 ASSERT(!pag->pagf_agflreset);
2690 be32_add_cpu(&agf->agf_flcount, -1);
2691 xfs_trans_agflist_delta(tp, -1);
2692 pag->pagf_flcount--;
2693
2694 logflags = XFS_AGF_FLFIRST | XFS_AGF_FLCOUNT;
2695 if (btreeblk) {
2696 be32_add_cpu(&agf->agf_btreeblks, 1);
2697 pag->pagf_btreeblks++;
2698 logflags |= XFS_AGF_BTREEBLKS;
2699 }
2700
2701 xfs_alloc_log_agf(tp, agbp, logflags);
2702 *bnop = bno;
2703
2704 return 0;
2705}
2706
2707/*
2708 * Log the given fields from the agf structure.
2709 */
2710void
2711xfs_alloc_log_agf(
2712 xfs_trans_t *tp, /* transaction pointer */
2713 xfs_buf_t *bp, /* buffer for a.g. freelist header */
2714 int fields) /* mask of fields to be logged (XFS_AGF_...) */
2715{
2716 int first; /* first byte offset */
2717 int last; /* last byte offset */
2718 static const short offsets[] = {
2719 offsetof(xfs_agf_t, agf_magicnum),
2720 offsetof(xfs_agf_t, agf_versionnum),
2721 offsetof(xfs_agf_t, agf_seqno),
2722 offsetof(xfs_agf_t, agf_length),
2723 offsetof(xfs_agf_t, agf_roots[0]),
2724 offsetof(xfs_agf_t, agf_levels[0]),
2725 offsetof(xfs_agf_t, agf_flfirst),
2726 offsetof(xfs_agf_t, agf_fllast),
2727 offsetof(xfs_agf_t, agf_flcount),
2728 offsetof(xfs_agf_t, agf_freeblks),
2729 offsetof(xfs_agf_t, agf_longest),
2730 offsetof(xfs_agf_t, agf_btreeblks),
2731 offsetof(xfs_agf_t, agf_uuid),
2732 offsetof(xfs_agf_t, agf_rmap_blocks),
2733 offsetof(xfs_agf_t, agf_refcount_blocks),
2734 offsetof(xfs_agf_t, agf_refcount_root),
2735 offsetof(xfs_agf_t, agf_refcount_level),
2736 /* needed so that we don't log the whole rest of the structure: */
2737 offsetof(xfs_agf_t, agf_spare64),
2738 sizeof(xfs_agf_t)
2739 };
2740
2741 trace_xfs_agf(tp->t_mountp, bp->b_addr, fields, _RET_IP_);
2742
2743 xfs_trans_buf_set_type(tp, bp, XFS_BLFT_AGF_BUF);
2744
2745 xfs_btree_offsets(fields, offsets, XFS_AGF_NUM_BITS, &first, &last);
2746 xfs_trans_log_buf(tp, bp, (uint)first, (uint)last);
2747}
2748
2749/*
2750 * Interface for inode allocation to force the pag data to be initialized.
2751 */
2752int /* error */
2753xfs_alloc_pagf_init(
2754 xfs_mount_t *mp, /* file system mount structure */
2755 xfs_trans_t *tp, /* transaction pointer */
2756 xfs_agnumber_t agno, /* allocation group number */
2757 int flags) /* XFS_ALLOC_FLAGS_... */
2758{
2759 xfs_buf_t *bp;
2760 int error;
2761
2762 error = xfs_alloc_read_agf(mp, tp, agno, flags, &bp);
2763 if (!error)
2764 xfs_trans_brelse(tp, bp);
2765 return error;
2766}
2767
2768/*
2769 * Put the block on the freelist for the allocation group.
2770 */
2771int /* error */
2772xfs_alloc_put_freelist(
2773 xfs_trans_t *tp, /* transaction pointer */
2774 xfs_buf_t *agbp, /* buffer for a.g. freelist header */
2775 xfs_buf_t *agflbp,/* buffer for a.g. free block array */
2776 xfs_agblock_t bno, /* block being freed */
2777 int btreeblk) /* block came from a AGF btree */
2778{
2779 struct xfs_mount *mp = tp->t_mountp;
2780 struct xfs_agf *agf = agbp->b_addr;
2781 __be32 *blockp;/* pointer to array entry */
2782 int error;
2783 int logflags;
2784 xfs_perag_t *pag; /* per allocation group data */
2785 __be32 *agfl_bno;
2786 int startoff;
2787
2788 if (!agflbp && (error = xfs_alloc_read_agfl(mp, tp,
2789 be32_to_cpu(agf->agf_seqno), &agflbp)))
2790 return error;
2791 be32_add_cpu(&agf->agf_fllast, 1);
2792 if (be32_to_cpu(agf->agf_fllast) == xfs_agfl_size(mp))
2793 agf->agf_fllast = 0;
2794
2795 pag = agbp->b_pag;
2796 ASSERT(!pag->pagf_agflreset);
2797 be32_add_cpu(&agf->agf_flcount, 1);
2798 xfs_trans_agflist_delta(tp, 1);
2799 pag->pagf_flcount++;
2800
2801 logflags = XFS_AGF_FLLAST | XFS_AGF_FLCOUNT;
2802 if (btreeblk) {
2803 be32_add_cpu(&agf->agf_btreeblks, -1);
2804 pag->pagf_btreeblks--;
2805 logflags |= XFS_AGF_BTREEBLKS;
2806 }
2807
2808 xfs_alloc_log_agf(tp, agbp, logflags);
2809
2810 ASSERT(be32_to_cpu(agf->agf_flcount) <= xfs_agfl_size(mp));
2811
2812 agfl_bno = xfs_buf_to_agfl_bno(agflbp);
2813 blockp = &agfl_bno[be32_to_cpu(agf->agf_fllast)];
2814 *blockp = cpu_to_be32(bno);
2815 startoff = (char *)blockp - (char *)agflbp->b_addr;
2816
2817 xfs_alloc_log_agf(tp, agbp, logflags);
2818
2819 xfs_trans_buf_set_type(tp, agflbp, XFS_BLFT_AGFL_BUF);
2820 xfs_trans_log_buf(tp, agflbp, startoff,
2821 startoff + sizeof(xfs_agblock_t) - 1);
2822 return 0;
2823}
2824
2825static xfs_failaddr_t
2826xfs_agf_verify(
2827 struct xfs_buf *bp)
2828{
2829 struct xfs_mount *mp = bp->b_mount;
2830 struct xfs_agf *agf = bp->b_addr;
2831
2832 if (xfs_sb_version_hascrc(&mp->m_sb)) {
2833 if (!uuid_equal(&agf->agf_uuid, &mp->m_sb.sb_meta_uuid))
2834 return __this_address;
2835 if (!xfs_log_check_lsn(mp, be64_to_cpu(agf->agf_lsn)))
2836 return __this_address;
2837 }
2838
2839 if (!xfs_verify_magic(bp, agf->agf_magicnum))
2840 return __this_address;
2841
2842 if (!(XFS_AGF_GOOD_VERSION(be32_to_cpu(agf->agf_versionnum)) &&
2843 be32_to_cpu(agf->agf_freeblks) <= be32_to_cpu(agf->agf_length) &&
2844 be32_to_cpu(agf->agf_flfirst) < xfs_agfl_size(mp) &&
2845 be32_to_cpu(agf->agf_fllast) < xfs_agfl_size(mp) &&
2846 be32_to_cpu(agf->agf_flcount) <= xfs_agfl_size(mp)))
2847 return __this_address;
2848
2849 if (be32_to_cpu(agf->agf_length) > mp->m_sb.sb_dblocks)
2850 return __this_address;
2851
2852 if (be32_to_cpu(agf->agf_freeblks) < be32_to_cpu(agf->agf_longest) ||
2853 be32_to_cpu(agf->agf_freeblks) > be32_to_cpu(agf->agf_length))
2854 return __this_address;
2855
2856 if (be32_to_cpu(agf->agf_levels[XFS_BTNUM_BNO]) < 1 ||
2857 be32_to_cpu(agf->agf_levels[XFS_BTNUM_CNT]) < 1 ||
2858 be32_to_cpu(agf->agf_levels[XFS_BTNUM_BNO]) > XFS_BTREE_MAXLEVELS ||
2859 be32_to_cpu(agf->agf_levels[XFS_BTNUM_CNT]) > XFS_BTREE_MAXLEVELS)
2860 return __this_address;
2861
2862 if (xfs_sb_version_hasrmapbt(&mp->m_sb) &&
2863 (be32_to_cpu(agf->agf_levels[XFS_BTNUM_RMAP]) < 1 ||
2864 be32_to_cpu(agf->agf_levels[XFS_BTNUM_RMAP]) > XFS_BTREE_MAXLEVELS))
2865 return __this_address;
2866
2867 if (xfs_sb_version_hasrmapbt(&mp->m_sb) &&
2868 be32_to_cpu(agf->agf_rmap_blocks) > be32_to_cpu(agf->agf_length))
2869 return __this_address;
2870
2871 /*
2872 * during growfs operations, the perag is not fully initialised,
2873 * so we can't use it for any useful checking. growfs ensures we can't
2874 * use it by using uncached buffers that don't have the perag attached
2875 * so we can detect and avoid this problem.
2876 */
2877 if (bp->b_pag && be32_to_cpu(agf->agf_seqno) != bp->b_pag->pag_agno)
2878 return __this_address;
2879
2880 if (xfs_sb_version_haslazysbcount(&mp->m_sb) &&
2881 be32_to_cpu(agf->agf_btreeblks) > be32_to_cpu(agf->agf_length))
2882 return __this_address;
2883
2884 if (xfs_sb_version_hasreflink(&mp->m_sb) &&
2885 be32_to_cpu(agf->agf_refcount_blocks) >
2886 be32_to_cpu(agf->agf_length))
2887 return __this_address;
2888
2889 if (xfs_sb_version_hasreflink(&mp->m_sb) &&
2890 (be32_to_cpu(agf->agf_refcount_level) < 1 ||
2891 be32_to_cpu(agf->agf_refcount_level) > XFS_BTREE_MAXLEVELS))
2892 return __this_address;
2893
2894 return NULL;
2895
2896}
2897
2898static void
2899xfs_agf_read_verify(
2900 struct xfs_buf *bp)
2901{
2902 struct xfs_mount *mp = bp->b_mount;
2903 xfs_failaddr_t fa;
2904
2905 if (xfs_sb_version_hascrc(&mp->m_sb) &&
2906 !xfs_buf_verify_cksum(bp, XFS_AGF_CRC_OFF))
2907 xfs_verifier_error(bp, -EFSBADCRC, __this_address);
2908 else {
2909 fa = xfs_agf_verify(bp);
2910 if (XFS_TEST_ERROR(fa, mp, XFS_ERRTAG_ALLOC_READ_AGF))
2911 xfs_verifier_error(bp, -EFSCORRUPTED, fa);
2912 }
2913}
2914
2915static void
2916xfs_agf_write_verify(
2917 struct xfs_buf *bp)
2918{
2919 struct xfs_mount *mp = bp->b_mount;
2920 struct xfs_buf_log_item *bip = bp->b_log_item;
2921 struct xfs_agf *agf = bp->b_addr;
2922 xfs_failaddr_t fa;
2923
2924 fa = xfs_agf_verify(bp);
2925 if (fa) {
2926 xfs_verifier_error(bp, -EFSCORRUPTED, fa);
2927 return;
2928 }
2929
2930 if (!xfs_sb_version_hascrc(&mp->m_sb))
2931 return;
2932
2933 if (bip)
2934 agf->agf_lsn = cpu_to_be64(bip->bli_item.li_lsn);
2935
2936 xfs_buf_update_cksum(bp, XFS_AGF_CRC_OFF);
2937}
2938
2939const struct xfs_buf_ops xfs_agf_buf_ops = {
2940 .name = "xfs_agf",
2941 .magic = { cpu_to_be32(XFS_AGF_MAGIC), cpu_to_be32(XFS_AGF_MAGIC) },
2942 .verify_read = xfs_agf_read_verify,
2943 .verify_write = xfs_agf_write_verify,
2944 .verify_struct = xfs_agf_verify,
2945};
2946
2947/*
2948 * Read in the allocation group header (free/alloc section).
2949 */
2950int /* error */
2951xfs_read_agf(
2952 struct xfs_mount *mp, /* mount point structure */
2953 struct xfs_trans *tp, /* transaction pointer */
2954 xfs_agnumber_t agno, /* allocation group number */
2955 int flags, /* XFS_BUF_ */
2956 struct xfs_buf **bpp) /* buffer for the ag freelist header */
2957{
2958 int error;
2959
2960 trace_xfs_read_agf(mp, agno);
2961
2962 ASSERT(agno != NULLAGNUMBER);
2963 error = xfs_trans_read_buf(mp, tp, mp->m_ddev_targp,
2964 XFS_AG_DADDR(mp, agno, XFS_AGF_DADDR(mp)),
2965 XFS_FSS_TO_BB(mp, 1), flags, bpp, &xfs_agf_buf_ops);
2966 if (error)
2967 return error;
2968
2969 ASSERT(!(*bpp)->b_error);
2970 xfs_buf_set_ref(*bpp, XFS_AGF_REF);
2971 return 0;
2972}
2973
2974/*
2975 * Read in the allocation group header (free/alloc section).
2976 */
2977int /* error */
2978xfs_alloc_read_agf(
2979 struct xfs_mount *mp, /* mount point structure */
2980 struct xfs_trans *tp, /* transaction pointer */
2981 xfs_agnumber_t agno, /* allocation group number */
2982 int flags, /* XFS_ALLOC_FLAG_... */
2983 struct xfs_buf **bpp) /* buffer for the ag freelist header */
2984{
2985 struct xfs_agf *agf; /* ag freelist header */
2986 struct xfs_perag *pag; /* per allocation group data */
2987 int error;
2988
2989 trace_xfs_alloc_read_agf(mp, agno);
2990
2991 /* We don't support trylock when freeing. */
2992 ASSERT((flags & (XFS_ALLOC_FLAG_FREEING | XFS_ALLOC_FLAG_TRYLOCK)) !=
2993 (XFS_ALLOC_FLAG_FREEING | XFS_ALLOC_FLAG_TRYLOCK));
2994 ASSERT(agno != NULLAGNUMBER);
2995 error = xfs_read_agf(mp, tp, agno,
2996 (flags & XFS_ALLOC_FLAG_TRYLOCK) ? XBF_TRYLOCK : 0,
2997 bpp);
2998 if (error)
2999 return error;
3000 ASSERT(!(*bpp)->b_error);
3001
3002 agf = (*bpp)->b_addr;
3003 pag = (*bpp)->b_pag;
3004 if (!pag->pagf_init) {
3005 pag->pagf_freeblks = be32_to_cpu(agf->agf_freeblks);
3006 pag->pagf_btreeblks = be32_to_cpu(agf->agf_btreeblks);
3007 pag->pagf_flcount = be32_to_cpu(agf->agf_flcount);
3008 pag->pagf_longest = be32_to_cpu(agf->agf_longest);
3009 pag->pagf_levels[XFS_BTNUM_BNOi] =
3010 be32_to_cpu(agf->agf_levels[XFS_BTNUM_BNOi]);
3011 pag->pagf_levels[XFS_BTNUM_CNTi] =
3012 be32_to_cpu(agf->agf_levels[XFS_BTNUM_CNTi]);
3013 pag->pagf_levels[XFS_BTNUM_RMAPi] =
3014 be32_to_cpu(agf->agf_levels[XFS_BTNUM_RMAPi]);
3015 pag->pagf_refcount_level = be32_to_cpu(agf->agf_refcount_level);
3016 pag->pagf_init = 1;
3017 pag->pagf_agflreset = xfs_agfl_needs_reset(mp, agf);
3018 }
3019#ifdef DEBUG
3020 else if (!XFS_FORCED_SHUTDOWN(mp)) {
3021 ASSERT(pag->pagf_freeblks == be32_to_cpu(agf->agf_freeblks));
3022 ASSERT(pag->pagf_btreeblks == be32_to_cpu(agf->agf_btreeblks));
3023 ASSERT(pag->pagf_flcount == be32_to_cpu(agf->agf_flcount));
3024 ASSERT(pag->pagf_longest == be32_to_cpu(agf->agf_longest));
3025 ASSERT(pag->pagf_levels[XFS_BTNUM_BNOi] ==
3026 be32_to_cpu(agf->agf_levels[XFS_BTNUM_BNOi]));
3027 ASSERT(pag->pagf_levels[XFS_BTNUM_CNTi] ==
3028 be32_to_cpu(agf->agf_levels[XFS_BTNUM_CNTi]));
3029 }
3030#endif
3031 return 0;
3032}
3033
3034/*
3035 * Allocate an extent (variable-size).
3036 * Depending on the allocation type, we either look in a single allocation
3037 * group or loop over the allocation groups to find the result.
3038 */
3039int /* error */
3040xfs_alloc_vextent(
3041 struct xfs_alloc_arg *args) /* allocation argument structure */
3042{
3043 xfs_agblock_t agsize; /* allocation group size */
3044 int error;
3045 int flags; /* XFS_ALLOC_FLAG_... locking flags */
3046 struct xfs_mount *mp; /* mount structure pointer */
3047 xfs_agnumber_t sagno; /* starting allocation group number */
3048 xfs_alloctype_t type; /* input allocation type */
3049 int bump_rotor = 0;
3050 xfs_agnumber_t rotorstep = xfs_rotorstep; /* inode32 agf stepper */
3051
3052 mp = args->mp;
3053 type = args->otype = args->type;
3054 args->agbno = NULLAGBLOCK;
3055 /*
3056 * Just fix this up, for the case where the last a.g. is shorter
3057 * (or there's only one a.g.) and the caller couldn't easily figure
3058 * that out (xfs_bmap_alloc).
3059 */
3060 agsize = mp->m_sb.sb_agblocks;
3061 if (args->maxlen > agsize)
3062 args->maxlen = agsize;
3063 if (args->alignment == 0)
3064 args->alignment = 1;
3065 ASSERT(XFS_FSB_TO_AGNO(mp, args->fsbno) < mp->m_sb.sb_agcount);
3066 ASSERT(XFS_FSB_TO_AGBNO(mp, args->fsbno) < agsize);
3067 ASSERT(args->minlen <= args->maxlen);
3068 ASSERT(args->minlen <= agsize);
3069 ASSERT(args->mod < args->prod);
3070 if (XFS_FSB_TO_AGNO(mp, args->fsbno) >= mp->m_sb.sb_agcount ||
3071 XFS_FSB_TO_AGBNO(mp, args->fsbno) >= agsize ||
3072 args->minlen > args->maxlen || args->minlen > agsize ||
3073 args->mod >= args->prod) {
3074 args->fsbno = NULLFSBLOCK;
3075 trace_xfs_alloc_vextent_badargs(args);
3076 return 0;
3077 }
3078
3079 switch (type) {
3080 case XFS_ALLOCTYPE_THIS_AG:
3081 case XFS_ALLOCTYPE_NEAR_BNO:
3082 case XFS_ALLOCTYPE_THIS_BNO:
3083 /*
3084 * These three force us into a single a.g.
3085 */
3086 args->agno = XFS_FSB_TO_AGNO(mp, args->fsbno);
3087 args->pag = xfs_perag_get(mp, args->agno);
3088 error = xfs_alloc_fix_freelist(args, 0);
3089 if (error) {
3090 trace_xfs_alloc_vextent_nofix(args);
3091 goto error0;
3092 }
3093 if (!args->agbp) {
3094 trace_xfs_alloc_vextent_noagbp(args);
3095 break;
3096 }
3097 args->agbno = XFS_FSB_TO_AGBNO(mp, args->fsbno);
3098 if ((error = xfs_alloc_ag_vextent(args)))
3099 goto error0;
3100 break;
3101 case XFS_ALLOCTYPE_START_BNO:
3102 /*
3103 * Try near allocation first, then anywhere-in-ag after
3104 * the first a.g. fails.
3105 */
3106 if ((args->datatype & XFS_ALLOC_INITIAL_USER_DATA) &&
3107 (mp->m_flags & XFS_MOUNT_32BITINODES)) {
3108 args->fsbno = XFS_AGB_TO_FSB(mp,
3109 ((mp->m_agfrotor / rotorstep) %
3110 mp->m_sb.sb_agcount), 0);
3111 bump_rotor = 1;
3112 }
3113 args->agbno = XFS_FSB_TO_AGBNO(mp, args->fsbno);
3114 args->type = XFS_ALLOCTYPE_NEAR_BNO;
3115 /* FALLTHROUGH */
3116 case XFS_ALLOCTYPE_FIRST_AG:
3117 /*
3118 * Rotate through the allocation groups looking for a winner.
3119 */
3120 if (type == XFS_ALLOCTYPE_FIRST_AG) {
3121 /*
3122 * Start with allocation group given by bno.
3123 */
3124 args->agno = XFS_FSB_TO_AGNO(mp, args->fsbno);
3125 args->type = XFS_ALLOCTYPE_THIS_AG;
3126 sagno = 0;
3127 flags = 0;
3128 } else {
3129 /*
3130 * Start with the given allocation group.
3131 */
3132 args->agno = sagno = XFS_FSB_TO_AGNO(mp, args->fsbno);
3133 flags = XFS_ALLOC_FLAG_TRYLOCK;
3134 }
3135 /*
3136 * Loop over allocation groups twice; first time with
3137 * trylock set, second time without.
3138 */
3139 for (;;) {
3140 args->pag = xfs_perag_get(mp, args->agno);
3141 error = xfs_alloc_fix_freelist(args, flags);
3142 if (error) {
3143 trace_xfs_alloc_vextent_nofix(args);
3144 goto error0;
3145 }
3146 /*
3147 * If we get a buffer back then the allocation will fly.
3148 */
3149 if (args->agbp) {
3150 if ((error = xfs_alloc_ag_vextent(args)))
3151 goto error0;
3152 break;
3153 }
3154
3155 trace_xfs_alloc_vextent_loopfailed(args);
3156
3157 /*
3158 * Didn't work, figure out the next iteration.
3159 */
3160 if (args->agno == sagno &&
3161 type == XFS_ALLOCTYPE_START_BNO)
3162 args->type = XFS_ALLOCTYPE_THIS_AG;
3163 /*
3164 * For the first allocation, we can try any AG to get
3165 * space. However, if we already have allocated a
3166 * block, we don't want to try AGs whose number is below
3167 * sagno. Otherwise, we may end up with out-of-order
3168 * locking of AGF, which might cause deadlock.
3169 */
3170 if (++(args->agno) == mp->m_sb.sb_agcount) {
3171 if (args->tp->t_firstblock != NULLFSBLOCK)
3172 args->agno = sagno;
3173 else
3174 args->agno = 0;
3175 }
3176 /*
3177 * Reached the starting a.g., must either be done
3178 * or switch to non-trylock mode.
3179 */
3180 if (args->agno == sagno) {
3181 if (flags == 0) {
3182 args->agbno = NULLAGBLOCK;
3183 trace_xfs_alloc_vextent_allfailed(args);
3184 break;
3185 }
3186
3187 flags = 0;
3188 if (type == XFS_ALLOCTYPE_START_BNO) {
3189 args->agbno = XFS_FSB_TO_AGBNO(mp,
3190 args->fsbno);
3191 args->type = XFS_ALLOCTYPE_NEAR_BNO;
3192 }
3193 }
3194 xfs_perag_put(args->pag);
3195 }
3196 if (bump_rotor) {
3197 if (args->agno == sagno)
3198 mp->m_agfrotor = (mp->m_agfrotor + 1) %
3199 (mp->m_sb.sb_agcount * rotorstep);
3200 else
3201 mp->m_agfrotor = (args->agno * rotorstep + 1) %
3202 (mp->m_sb.sb_agcount * rotorstep);
3203 }
3204 break;
3205 default:
3206 ASSERT(0);
3207 /* NOTREACHED */
3208 }
3209 if (args->agbno == NULLAGBLOCK)
3210 args->fsbno = NULLFSBLOCK;
3211 else {
3212 args->fsbno = XFS_AGB_TO_FSB(mp, args->agno, args->agbno);
3213#ifdef DEBUG
3214 ASSERT(args->len >= args->minlen);
3215 ASSERT(args->len <= args->maxlen);
3216 ASSERT(args->agbno % args->alignment == 0);
3217 XFS_AG_CHECK_DADDR(mp, XFS_FSB_TO_DADDR(mp, args->fsbno),
3218 args->len);
3219#endif
3220
3221 }
3222 xfs_perag_put(args->pag);
3223 return 0;
3224error0:
3225 xfs_perag_put(args->pag);
3226 return error;
3227}
3228
3229/* Ensure that the freelist is at full capacity. */
3230int
3231xfs_free_extent_fix_freelist(
3232 struct xfs_trans *tp,
3233 xfs_agnumber_t agno,
3234 struct xfs_buf **agbp)
3235{
3236 struct xfs_alloc_arg args;
3237 int error;
3238
3239 memset(&args, 0, sizeof(struct xfs_alloc_arg));
3240 args.tp = tp;
3241 args.mp = tp->t_mountp;
3242 args.agno = agno;
3243
3244 /*
3245 * validate that the block number is legal - the enables us to detect
3246 * and handle a silent filesystem corruption rather than crashing.
3247 */
3248 if (args.agno >= args.mp->m_sb.sb_agcount)
3249 return -EFSCORRUPTED;
3250
3251 args.pag = xfs_perag_get(args.mp, args.agno);
3252 ASSERT(args.pag);
3253
3254 error = xfs_alloc_fix_freelist(&args, XFS_ALLOC_FLAG_FREEING);
3255 if (error)
3256 goto out;
3257
3258 *agbp = args.agbp;
3259out:
3260 xfs_perag_put(args.pag);
3261 return error;
3262}
3263
3264/*
3265 * Free an extent.
3266 * Just break up the extent address and hand off to xfs_free_ag_extent
3267 * after fixing up the freelist.
3268 */
3269int
3270__xfs_free_extent(
3271 struct xfs_trans *tp,
3272 xfs_fsblock_t bno,
3273 xfs_extlen_t len,
3274 const struct xfs_owner_info *oinfo,
3275 enum xfs_ag_resv_type type,
3276 bool skip_discard)
3277{
3278 struct xfs_mount *mp = tp->t_mountp;
3279 struct xfs_buf *agbp;
3280 xfs_agnumber_t agno = XFS_FSB_TO_AGNO(mp, bno);
3281 xfs_agblock_t agbno = XFS_FSB_TO_AGBNO(mp, bno);
3282 struct xfs_agf *agf;
3283 int error;
3284 unsigned int busy_flags = 0;
3285
3286 ASSERT(len != 0);
3287 ASSERT(type != XFS_AG_RESV_AGFL);
3288
3289 if (XFS_TEST_ERROR(false, mp,
3290 XFS_ERRTAG_FREE_EXTENT))
3291 return -EIO;
3292
3293 error = xfs_free_extent_fix_freelist(tp, agno, &agbp);
3294 if (error)
3295 return error;
3296 agf = agbp->b_addr;
3297
3298 if (XFS_IS_CORRUPT(mp, agbno >= mp->m_sb.sb_agblocks)) {
3299 error = -EFSCORRUPTED;
3300 goto err;
3301 }
3302
3303 /* validate the extent size is legal now we have the agf locked */
3304 if (XFS_IS_CORRUPT(mp, agbno + len > be32_to_cpu(agf->agf_length))) {
3305 error = -EFSCORRUPTED;
3306 goto err;
3307 }
3308
3309 error = xfs_free_ag_extent(tp, agbp, agno, agbno, len, oinfo, type);
3310 if (error)
3311 goto err;
3312
3313 if (skip_discard)
3314 busy_flags |= XFS_EXTENT_BUSY_SKIP_DISCARD;
3315 xfs_extent_busy_insert(tp, agno, agbno, len, busy_flags);
3316 return 0;
3317
3318err:
3319 xfs_trans_brelse(tp, agbp);
3320 return error;
3321}
3322
3323struct xfs_alloc_query_range_info {
3324 xfs_alloc_query_range_fn fn;
3325 void *priv;
3326};
3327
3328/* Format btree record and pass to our callback. */
3329STATIC int
3330xfs_alloc_query_range_helper(
3331 struct xfs_btree_cur *cur,
3332 union xfs_btree_rec *rec,
3333 void *priv)
3334{
3335 struct xfs_alloc_query_range_info *query = priv;
3336 struct xfs_alloc_rec_incore irec;
3337
3338 irec.ar_startblock = be32_to_cpu(rec->alloc.ar_startblock);
3339 irec.ar_blockcount = be32_to_cpu(rec->alloc.ar_blockcount);
3340 return query->fn(cur, &irec, query->priv);
3341}
3342
3343/* Find all free space within a given range of blocks. */
3344int
3345xfs_alloc_query_range(
3346 struct xfs_btree_cur *cur,
3347 struct xfs_alloc_rec_incore *low_rec,
3348 struct xfs_alloc_rec_incore *high_rec,
3349 xfs_alloc_query_range_fn fn,
3350 void *priv)
3351{
3352 union xfs_btree_irec low_brec;
3353 union xfs_btree_irec high_brec;
3354 struct xfs_alloc_query_range_info query;
3355
3356 ASSERT(cur->bc_btnum == XFS_BTNUM_BNO);
3357 low_brec.a = *low_rec;
3358 high_brec.a = *high_rec;
3359 query.priv = priv;
3360 query.fn = fn;
3361 return xfs_btree_query_range(cur, &low_brec, &high_brec,
3362 xfs_alloc_query_range_helper, &query);
3363}
3364
3365/* Find all free space records. */
3366int
3367xfs_alloc_query_all(
3368 struct xfs_btree_cur *cur,
3369 xfs_alloc_query_range_fn fn,
3370 void *priv)
3371{
3372 struct xfs_alloc_query_range_info query;
3373
3374 ASSERT(cur->bc_btnum == XFS_BTNUM_BNO);
3375 query.priv = priv;
3376 query.fn = fn;
3377 return xfs_btree_query_all(cur, xfs_alloc_query_range_helper, &query);
3378}
3379
3380/* Is there a record covering a given extent? */
3381int
3382xfs_alloc_has_record(
3383 struct xfs_btree_cur *cur,
3384 xfs_agblock_t bno,
3385 xfs_extlen_t len,
3386 bool *exists)
3387{
3388 union xfs_btree_irec low;
3389 union xfs_btree_irec high;
3390
3391 memset(&low, 0, sizeof(low));
3392 low.a.ar_startblock = bno;
3393 memset(&high, 0xFF, sizeof(high));
3394 high.a.ar_startblock = bno + len - 1;
3395
3396 return xfs_btree_has_record(cur, &low, &high, exists);
3397}
3398
3399/*
3400 * Walk all the blocks in the AGFL. The @walk_fn can return any negative
3401 * error code or XFS_ITER_*.
3402 */
3403int
3404xfs_agfl_walk(
3405 struct xfs_mount *mp,
3406 struct xfs_agf *agf,
3407 struct xfs_buf *agflbp,
3408 xfs_agfl_walk_fn walk_fn,
3409 void *priv)
3410{
3411 __be32 *agfl_bno;
3412 unsigned int i;
3413 int error;
3414
3415 agfl_bno = xfs_buf_to_agfl_bno(agflbp);
3416 i = be32_to_cpu(agf->agf_flfirst);
3417
3418 /* Nothing to walk in an empty AGFL. */
3419 if (agf->agf_flcount == cpu_to_be32(0))
3420 return 0;
3421
3422 /* Otherwise, walk from first to last, wrapping as needed. */
3423 for (;;) {
3424 error = walk_fn(mp, be32_to_cpu(agfl_bno[i]), priv);
3425 if (error)
3426 return error;
3427 if (i == be32_to_cpu(agf->agf_fllast))
3428 break;
3429 if (++i == xfs_agfl_size(mp))
3430 i = 0;
3431 }
3432
3433 return 0;
3434}