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Merge branch 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel...
[linux-2.6.git] / fs / xfs / xfs_alloc.c
blob5673bcfda2f0c8c0151142b52dc5202d7030da63
1 /*
2 * Copyright (c) 2000-2002,2005 Silicon Graphics, Inc.
3 * All Rights Reserved.
4 *
5 * This program is free software; you can redistribute it and/or
6 * modify it under the terms of the GNU General Public License as
7 * published by the Free Software Foundation.
8 *
9 * This program is distributed in the hope that it would be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
13 *
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, write the Free Software Foundation,
16 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
17 */
18 #include "xfs.h"
19 #include "xfs_fs.h"
20 #include "xfs_types.h"
21 #include "xfs_bit.h"
22 #include "xfs_log.h"
23 #include "xfs_trans.h"
24 #include "xfs_sb.h"
25 #include "xfs_ag.h"
26 #include "xfs_mount.h"
27 #include "xfs_bmap_btree.h"
28 #include "xfs_alloc_btree.h"
29 #include "xfs_ialloc_btree.h"
30 #include "xfs_dinode.h"
31 #include "xfs_inode.h"
32 #include "xfs_btree.h"
33 #include "xfs_alloc.h"
34 #include "xfs_extent_busy.h"
35 #include "xfs_error.h"
36 #include "xfs_cksum.h"
37 #include "xfs_trace.h"
38 #include "xfs_buf_item.h"
39
40 struct workqueue_struct *xfs_alloc_wq;
41
42 #define XFS_ABSDIFF(a,b) (((a) <= (b)) ? ((b) - (a)) : ((a) - (b)))
43
44 #define XFSA_FIXUP_BNO_OK 1
45 #define XFSA_FIXUP_CNT_OK 2
46
47 STATIC int xfs_alloc_ag_vextent_exact(xfs_alloc_arg_t *);
48 STATIC int xfs_alloc_ag_vextent_near(xfs_alloc_arg_t *);
49 STATIC int xfs_alloc_ag_vextent_size(xfs_alloc_arg_t *);
50 STATIC int xfs_alloc_ag_vextent_small(xfs_alloc_arg_t *,
51 xfs_btree_cur_t *, xfs_agblock_t *, xfs_extlen_t *, int *);
52
53 /*
54 * Lookup the record equal to [bno, len] in the btree given by cur.
55 */
56 STATIC int /* error */
57 xfs_alloc_lookup_eq(
58 struct xfs_btree_cur *cur, /* btree cursor */
59 xfs_agblock_t bno, /* starting block of extent */
60 xfs_extlen_t len, /* length of extent */
61 int *stat) /* success/failure */
62 {
63 cur->bc_rec.a.ar_startblock = bno;
64 cur->bc_rec.a.ar_blockcount = len;
65 return xfs_btree_lookup(cur, XFS_LOOKUP_EQ, stat);
66 }
67
68 /*
69 * Lookup the first record greater than or equal to [bno, len]
70 * in the btree given by cur.
71 */
72 int /* error */
73 xfs_alloc_lookup_ge(
74 struct xfs_btree_cur *cur, /* btree cursor */
75 xfs_agblock_t bno, /* starting block of extent */
76 xfs_extlen_t len, /* length of extent */
77 int *stat) /* success/failure */
78 {
79 cur->bc_rec.a.ar_startblock = bno;
80 cur->bc_rec.a.ar_blockcount = len;
81 return xfs_btree_lookup(cur, XFS_LOOKUP_GE, stat);
82 }
83
84 /*
85 * Lookup the first record less than or equal to [bno, len]
86 * in the btree given by cur.
87 */
88 int /* error */
89 xfs_alloc_lookup_le(
90 struct xfs_btree_cur *cur, /* btree cursor */
91 xfs_agblock_t bno, /* starting block of extent */
92 xfs_extlen_t len, /* length of extent */
93 int *stat) /* success/failure */
94 {
95 cur->bc_rec.a.ar_startblock = bno;
96 cur->bc_rec.a.ar_blockcount = len;
97 return xfs_btree_lookup(cur, XFS_LOOKUP_LE, stat);
98 }
99
100 /*
101 * Update the record referred to by cur to the value given
102 * by [bno, len].
103 * This either works (return 0) or gets an EFSCORRUPTED error.
104 */
105 STATIC int /* error */
106 xfs_alloc_update(
107 struct xfs_btree_cur *cur, /* btree cursor */
108 xfs_agblock_t bno, /* starting block of extent */
109 xfs_extlen_t len) /* length of extent */
110 {
111 union xfs_btree_rec rec;
112
113 rec.alloc.ar_startblock = cpu_to_be32(bno);
114 rec.alloc.ar_blockcount = cpu_to_be32(len);
115 return xfs_btree_update(cur, &rec);
116 }
117
118 /*
119 * Get the data from the pointed-to record.
120 */
121 int /* error */
122 xfs_alloc_get_rec(
123 struct xfs_btree_cur *cur, /* btree cursor */
124 xfs_agblock_t *bno, /* output: starting block of extent */
125 xfs_extlen_t *len, /* output: length of extent */
126 int *stat) /* output: success/failure */
127 {
128 union xfs_btree_rec *rec;
129 int error;
130
131 error = xfs_btree_get_rec(cur, &rec, stat);
132 if (!error && *stat == 1) {
133 *bno = be32_to_cpu(rec->alloc.ar_startblock);
134 *len = be32_to_cpu(rec->alloc.ar_blockcount);
135 }
136 return error;
137 }
138
139 /*
140 * Compute aligned version of the found extent.
141 * Takes alignment and min length into account.
142 */
143 STATIC void
144 xfs_alloc_compute_aligned(
145 xfs_alloc_arg_t *args, /* allocation argument structure */
146 xfs_agblock_t foundbno, /* starting block in found extent */
147 xfs_extlen_t foundlen, /* length in found extent */
148 xfs_agblock_t *resbno, /* result block number */
149 xfs_extlen_t *reslen) /* result length */
150 {
151 xfs_agblock_t bno;
152 xfs_extlen_t len;
153
154 /* Trim busy sections out of found extent */
155 xfs_extent_busy_trim(args, foundbno, foundlen, &bno, &len);
156
157 if (args->alignment > 1 && len >= args->minlen) {
158 xfs_agblock_t aligned_bno = roundup(bno, args->alignment);
159 xfs_extlen_t diff = aligned_bno - bno;
160
161 *resbno = aligned_bno;
162 *reslen = diff >= len ? 0 : len - diff;
163 } else {
164 *resbno = bno;
165 *reslen = len;
166 }
167 }
168
169 /*
170 * Compute best start block and diff for "near" allocations.
171 * freelen >= wantlen already checked by caller.
172 */
173 STATIC xfs_extlen_t /* difference value (absolute) */
174 xfs_alloc_compute_diff(
175 xfs_agblock_t wantbno, /* target starting block */
176 xfs_extlen_t wantlen, /* target length */
177 xfs_extlen_t alignment, /* target alignment */
178 xfs_agblock_t freebno, /* freespace's starting block */
179 xfs_extlen_t freelen, /* freespace's length */
180 xfs_agblock_t *newbnop) /* result: best start block from free */
181 {
182 xfs_agblock_t freeend; /* end of freespace extent */
183 xfs_agblock_t newbno1; /* return block number */
184 xfs_agblock_t newbno2; /* other new block number */
185 xfs_extlen_t newlen1=0; /* length with newbno1 */
186 xfs_extlen_t newlen2=0; /* length with newbno2 */
187 xfs_agblock_t wantend; /* end of target extent */
188
189 ASSERT(freelen >= wantlen);
190 freeend = freebno + freelen;
191 wantend = wantbno + wantlen;
192 if (freebno >= wantbno) {
193 if ((newbno1 = roundup(freebno, alignment)) >= freeend)
194 newbno1 = NULLAGBLOCK;
195 } else if (freeend >= wantend && alignment > 1) {
196 newbno1 = roundup(wantbno, alignment);
197 newbno2 = newbno1 - alignment;
198 if (newbno1 >= freeend)
199 newbno1 = NULLAGBLOCK;
200 else
201 newlen1 = XFS_EXTLEN_MIN(wantlen, freeend - newbno1);
202 if (newbno2 < freebno)
203 newbno2 = NULLAGBLOCK;
204 else
205 newlen2 = XFS_EXTLEN_MIN(wantlen, freeend - newbno2);
206 if (newbno1 != NULLAGBLOCK && newbno2 != NULLAGBLOCK) {
207 if (newlen1 < newlen2 ||
208 (newlen1 == newlen2 &&
209 XFS_ABSDIFF(newbno1, wantbno) >
210 XFS_ABSDIFF(newbno2, wantbno)))
211 newbno1 = newbno2;
212 } else if (newbno2 != NULLAGBLOCK)
213 newbno1 = newbno2;
214 } else if (freeend >= wantend) {
215 newbno1 = wantbno;
216 } else if (alignment > 1) {
217 newbno1 = roundup(freeend - wantlen, alignment);
218 if (newbno1 > freeend - wantlen &&
219 newbno1 - alignment >= freebno)
220 newbno1 -= alignment;
221 else if (newbno1 >= freeend)
222 newbno1 = NULLAGBLOCK;
223 } else
224 newbno1 = freeend - wantlen;
225 *newbnop = newbno1;
226 return newbno1 == NULLAGBLOCK ? 0 : XFS_ABSDIFF(newbno1, wantbno);
227 }
228
229 /*
230 * Fix up the length, based on mod and prod.
231 * len should be k * prod + mod for some k.
232 * If len is too small it is returned unchanged.
233 * If len hits maxlen it is left alone.
234 */
235 STATIC void
236 xfs_alloc_fix_len(
237 xfs_alloc_arg_t *args) /* allocation argument structure */
238 {
239 xfs_extlen_t k;
240 xfs_extlen_t rlen;
241
242 ASSERT(args->mod < args->prod);
243 rlen = args->len;
244 ASSERT(rlen >= args->minlen);
245 ASSERT(rlen <= args->maxlen);
246 if (args->prod <= 1 || rlen < args->mod || rlen == args->maxlen ||
247 (args->mod == 0 && rlen < args->prod))
248 return;
249 k = rlen % args->prod;
250 if (k == args->mod)
251 return;
252 if (k > args->mod) {
253 if ((int)(rlen = rlen - k - args->mod) < (int)args->minlen)
254 return;
255 } else {
256 if ((int)(rlen = rlen - args->prod - (args->mod - k)) <
257 (int)args->minlen)
258 return;
259 }
260 ASSERT(rlen >= args->minlen);
261 ASSERT(rlen <= args->maxlen);
262 args->len = rlen;
263 }
264
265 /*
266 * Fix up length if there is too little space left in the a.g.
267 * Return 1 if ok, 0 if too little, should give up.
268 */
269 STATIC int
270 xfs_alloc_fix_minleft(
271 xfs_alloc_arg_t *args) /* allocation argument structure */
272 {
273 xfs_agf_t *agf; /* a.g. freelist header */
274 int diff; /* free space difference */
275
276 if (args->minleft == 0)
277 return 1;
278 agf = XFS_BUF_TO_AGF(args->agbp);
279 diff = be32_to_cpu(agf->agf_freeblks)
280 - args->len - args->minleft;
281 if (diff >= 0)
282 return 1;
283 args->len += diff; /* shrink the allocated space */
284 if (args->len >= args->minlen)
285 return 1;
286 args->agbno = NULLAGBLOCK;
287 return 0;
288 }
289
290 /*
291 * Update the two btrees, logically removing from freespace the extent
292 * starting at rbno, rlen blocks. The extent is contained within the
293 * actual (current) free extent fbno for flen blocks.
294 * Flags are passed in indicating whether the cursors are set to the
295 * relevant records.
296 */
297 STATIC int /* error code */
298 xfs_alloc_fixup_trees(
299 xfs_btree_cur_t *cnt_cur, /* cursor for by-size btree */
300 xfs_btree_cur_t *bno_cur, /* cursor for by-block btree */
301 xfs_agblock_t fbno, /* starting block of free extent */
302 xfs_extlen_t flen, /* length of free extent */
303 xfs_agblock_t rbno, /* starting block of returned extent */
304 xfs_extlen_t rlen, /* length of returned extent */
305 int flags) /* flags, XFSA_FIXUP_... */
306 {
307 int error; /* error code */
308 int i; /* operation results */
309 xfs_agblock_t nfbno1; /* first new free startblock */
310 xfs_agblock_t nfbno2; /* second new free startblock */
311 xfs_extlen_t nflen1=0; /* first new free length */
312 xfs_extlen_t nflen2=0; /* second new free length */
313
314 /*
315 * Look up the record in the by-size tree if necessary.
316 */
317 if (flags & XFSA_FIXUP_CNT_OK) {
318 #ifdef DEBUG
319 if ((error = xfs_alloc_get_rec(cnt_cur, &nfbno1, &nflen1, &i)))
320 return error;
321 XFS_WANT_CORRUPTED_RETURN(
322 i == 1 && nfbno1 == fbno && nflen1 == flen);
323 #endif
324 } else {
325 if ((error = xfs_alloc_lookup_eq(cnt_cur, fbno, flen, &i)))
326 return error;
327 XFS_WANT_CORRUPTED_RETURN(i == 1);
328 }
329 /*
330 * Look up the record in the by-block tree if necessary.
331 */
332 if (flags & XFSA_FIXUP_BNO_OK) {
333 #ifdef DEBUG
334 if ((error = xfs_alloc_get_rec(bno_cur, &nfbno1, &nflen1, &i)))
335 return error;
336 XFS_WANT_CORRUPTED_RETURN(
337 i == 1 && nfbno1 == fbno && nflen1 == flen);
338 #endif
339 } else {
340 if ((error = xfs_alloc_lookup_eq(bno_cur, fbno, flen, &i)))
341 return error;
342 XFS_WANT_CORRUPTED_RETURN(i == 1);
343 }
344
345 #ifdef DEBUG
346 if (bno_cur->bc_nlevels == 1 && cnt_cur->bc_nlevels == 1) {
347 struct xfs_btree_block *bnoblock;
348 struct xfs_btree_block *cntblock;
349
350 bnoblock = XFS_BUF_TO_BLOCK(bno_cur->bc_bufs[0]);
351 cntblock = XFS_BUF_TO_BLOCK(cnt_cur->bc_bufs[0]);
352
353 XFS_WANT_CORRUPTED_RETURN(
354 bnoblock->bb_numrecs == cntblock->bb_numrecs);
355 }
356 #endif
357
358 /*
359 * Deal with all four cases: the allocated record is contained
360 * within the freespace record, so we can have new freespace
361 * at either (or both) end, or no freespace remaining.
362 */
363 if (rbno == fbno && rlen == flen)
364 nfbno1 = nfbno2 = NULLAGBLOCK;
365 else if (rbno == fbno) {
366 nfbno1 = rbno + rlen;
367 nflen1 = flen - rlen;
368 nfbno2 = NULLAGBLOCK;
369 } else if (rbno + rlen == fbno + flen) {
370 nfbno1 = fbno;
371 nflen1 = flen - rlen;
372 nfbno2 = NULLAGBLOCK;
373 } else {
374 nfbno1 = fbno;
375 nflen1 = rbno - fbno;
376 nfbno2 = rbno + rlen;
377 nflen2 = (fbno + flen) - nfbno2;
378 }
379 /*
380 * Delete the entry from the by-size btree.
381 */
382 if ((error = xfs_btree_delete(cnt_cur, &i)))
383 return error;
384 XFS_WANT_CORRUPTED_RETURN(i == 1);
385 /*
386 * Add new by-size btree entry(s).
387 */
388 if (nfbno1 != NULLAGBLOCK) {
389 if ((error = xfs_alloc_lookup_eq(cnt_cur, nfbno1, nflen1, &i)))
390 return error;
391 XFS_WANT_CORRUPTED_RETURN(i == 0);
392 if ((error = xfs_btree_insert(cnt_cur, &i)))
393 return error;
394 XFS_WANT_CORRUPTED_RETURN(i == 1);
395 }
396 if (nfbno2 != NULLAGBLOCK) {
397 if ((error = xfs_alloc_lookup_eq(cnt_cur, nfbno2, nflen2, &i)))
398 return error;
399 XFS_WANT_CORRUPTED_RETURN(i == 0);
400 if ((error = xfs_btree_insert(cnt_cur, &i)))
401 return error;
402 XFS_WANT_CORRUPTED_RETURN(i == 1);
403 }
404 /*
405 * Fix up the by-block btree entry(s).
406 */
407 if (nfbno1 == NULLAGBLOCK) {
408 /*
409 * No remaining freespace, just delete the by-block tree entry.
410 */
411 if ((error = xfs_btree_delete(bno_cur, &i)))
412 return error;
413 XFS_WANT_CORRUPTED_RETURN(i == 1);
414 } else {
415 /*
416 * Update the by-block entry to start later|be shorter.
417 */
418 if ((error = xfs_alloc_update(bno_cur, nfbno1, nflen1)))
419 return error;
420 }
421 if (nfbno2 != NULLAGBLOCK) {
422 /*
423 * 2 resulting free entries, need to add one.
424 */
425 if ((error = xfs_alloc_lookup_eq(bno_cur, nfbno2, nflen2, &i)))
426 return error;
427 XFS_WANT_CORRUPTED_RETURN(i == 0);
428 if ((error = xfs_btree_insert(bno_cur, &i)))
429 return error;
430 XFS_WANT_CORRUPTED_RETURN(i == 1);
431 }
432 return 0;
433 }
434
435 static bool
436 xfs_agfl_verify(
437 struct xfs_buf *bp)
438 {
439 struct xfs_mount *mp = bp->b_target->bt_mount;
440 struct xfs_agfl *agfl = XFS_BUF_TO_AGFL(bp);
441 int i;
442
443 if (!uuid_equal(&agfl->agfl_uuid, &mp->m_sb.sb_uuid))
444 return false;
445 if (be32_to_cpu(agfl->agfl_magicnum) != XFS_AGFL_MAGIC)
446 return false;
447 /*
448 * during growfs operations, the perag is not fully initialised,
449 * so we can't use it for any useful checking. growfs ensures we can't
450 * use it by using uncached buffers that don't have the perag attached
451 * so we can detect and avoid this problem.
452 */
453 if (bp->b_pag && be32_to_cpu(agfl->agfl_seqno) != bp->b_pag->pag_agno)
454 return false;
455
456 for (i = 0; i < XFS_AGFL_SIZE(mp); i++) {
457 if (be32_to_cpu(agfl->agfl_bno[i]) != NULLAGBLOCK &&
458 be32_to_cpu(agfl->agfl_bno[i]) >= mp->m_sb.sb_agblocks)
459 return false;
460 }
461 return true;
462 }
463
464 static void
465 xfs_agfl_read_verify(
466 struct xfs_buf *bp)
467 {
468 struct xfs_mount *mp = bp->b_target->bt_mount;
469 int agfl_ok = 1;
470
471 /*
472 * There is no verification of non-crc AGFLs because mkfs does not
473 * initialise the AGFL to zero or NULL. Hence the only valid part of the
474 * AGFL is what the AGF says is active. We can't get to the AGF, so we
475 * can't verify just those entries are valid.
476 */
477 if (!xfs_sb_version_hascrc(&mp->m_sb))
478 return;
479
480 agfl_ok = xfs_verify_cksum(bp->b_addr, BBTOB(bp->b_length),
481 offsetof(struct xfs_agfl, agfl_crc));
482
483 agfl_ok = agfl_ok && xfs_agfl_verify(bp);
484
485 if (!agfl_ok) {
486 XFS_CORRUPTION_ERROR(__func__, XFS_ERRLEVEL_LOW, mp, bp->b_addr);
487 xfs_buf_ioerror(bp, EFSCORRUPTED);
488 }
489 }
490
491 static void
492 xfs_agfl_write_verify(
493 struct xfs_buf *bp)
494 {
495 struct xfs_mount *mp = bp->b_target->bt_mount;
496 struct xfs_buf_log_item *bip = bp->b_fspriv;
497
498 /* no verification of non-crc AGFLs */
499 if (!xfs_sb_version_hascrc(&mp->m_sb))
500 return;
501
502 if (!xfs_agfl_verify(bp)) {
503 XFS_CORRUPTION_ERROR(__func__, XFS_ERRLEVEL_LOW, mp, bp->b_addr);
504 xfs_buf_ioerror(bp, EFSCORRUPTED);
505 return;
506 }
507
508 if (bip)
509 XFS_BUF_TO_AGFL(bp)->agfl_lsn = cpu_to_be64(bip->bli_item.li_lsn);
510
511 xfs_update_cksum(bp->b_addr, BBTOB(bp->b_length),
512 offsetof(struct xfs_agfl, agfl_crc));
513 }
514
515 const struct xfs_buf_ops xfs_agfl_buf_ops = {
516 .verify_read = xfs_agfl_read_verify,
517 .verify_write = xfs_agfl_write_verify,
518 };
519
520 /*
521 * Read in the allocation group free block array.
522 */
523 STATIC int /* error */
524 xfs_alloc_read_agfl(
525 xfs_mount_t *mp, /* mount point structure */
526 xfs_trans_t *tp, /* transaction pointer */
527 xfs_agnumber_t agno, /* allocation group number */
528 xfs_buf_t **bpp) /* buffer for the ag free block array */
529 {
530 xfs_buf_t *bp; /* return value */
531 int error;
532
533 ASSERT(agno != NULLAGNUMBER);
534 error = xfs_trans_read_buf(
535 mp, tp, mp->m_ddev_targp,
536 XFS_AG_DADDR(mp, agno, XFS_AGFL_DADDR(mp)),
537 XFS_FSS_TO_BB(mp, 1), 0, &bp, &xfs_agfl_buf_ops);
538 if (error)
539 return error;
540 ASSERT(!xfs_buf_geterror(bp));
541 xfs_buf_set_ref(bp, XFS_AGFL_REF);
542 *bpp = bp;
543 return 0;
544 }
545
546 STATIC int
547 xfs_alloc_update_counters(
548 struct xfs_trans *tp,
549 struct xfs_perag *pag,
550 struct xfs_buf *agbp,
551 long len)
552 {
553 struct xfs_agf *agf = XFS_BUF_TO_AGF(agbp);
554
555 pag->pagf_freeblks += len;
556 be32_add_cpu(&agf->agf_freeblks, len);
557
558 xfs_trans_agblocks_delta(tp, len);
559 if (unlikely(be32_to_cpu(agf->agf_freeblks) >
560 be32_to_cpu(agf->agf_length)))
561 return EFSCORRUPTED;
562
563 xfs_alloc_log_agf(tp, agbp, XFS_AGF_FREEBLKS);
564 return 0;
565 }
566
567 /*
568 * Allocation group level functions.
569 */
570
571 /*
572 * Allocate a variable extent in the allocation group agno.
573 * Type and bno are used to determine where in the allocation group the
574 * extent will start.
575 * Extent's length (returned in *len) will be between minlen and maxlen,
576 * and of the form k * prod + mod unless there's nothing that large.
577 * Return the starting a.g. block, or NULLAGBLOCK if we can't do it.
578 */
579 STATIC int /* error */
580 xfs_alloc_ag_vextent(
581 xfs_alloc_arg_t *args) /* argument structure for allocation */
582 {
583 int error=0;
584
585 ASSERT(args->minlen > 0);
586 ASSERT(args->maxlen > 0);
587 ASSERT(args->minlen <= args->maxlen);
588 ASSERT(args->mod < args->prod);
589 ASSERT(args->alignment > 0);
590 /*
591 * Branch to correct routine based on the type.
592 */
593 args->wasfromfl = 0;
594 switch (args->type) {
595 case XFS_ALLOCTYPE_THIS_AG:
596 error = xfs_alloc_ag_vextent_size(args);
597 break;
598 case XFS_ALLOCTYPE_NEAR_BNO:
599 error = xfs_alloc_ag_vextent_near(args);
600 break;
601 case XFS_ALLOCTYPE_THIS_BNO:
602 error = xfs_alloc_ag_vextent_exact(args);
603 break;
604 default:
605 ASSERT(0);
606 /* NOTREACHED */
607 }
608
609 if (error || args->agbno == NULLAGBLOCK)
610 return error;
611
612 ASSERT(args->len >= args->minlen);
613 ASSERT(args->len <= args->maxlen);
614 ASSERT(!args->wasfromfl || !args->isfl);
615 ASSERT(args->agbno % args->alignment == 0);
616
617 if (!args->wasfromfl) {
618 error = xfs_alloc_update_counters(args->tp, args->pag,
619 args->agbp,
620 -((long)(args->len)));
621 if (error)
622 return error;
623
624 ASSERT(!xfs_extent_busy_search(args->mp, args->agno,
625 args->agbno, args->len));
626 }
627
628 if (!args->isfl) {
629 xfs_trans_mod_sb(args->tp, args->wasdel ?
630 XFS_TRANS_SB_RES_FDBLOCKS :
631 XFS_TRANS_SB_FDBLOCKS,
632 -((long)(args->len)));
633 }
634
635 XFS_STATS_INC(xs_allocx);
636 XFS_STATS_ADD(xs_allocb, args->len);
637 return error;
638 }
639
640 /*
641 * Allocate a variable extent at exactly agno/bno.
642 * Extent's length (returned in *len) will be between minlen and maxlen,
643 * and of the form k * prod + mod unless there's nothing that large.
644 * Return the starting a.g. block (bno), or NULLAGBLOCK if we can't do it.
645 */
646 STATIC int /* error */
647 xfs_alloc_ag_vextent_exact(
648 xfs_alloc_arg_t *args) /* allocation argument structure */
649 {
650 xfs_btree_cur_t *bno_cur;/* by block-number btree cursor */
651 xfs_btree_cur_t *cnt_cur;/* by count btree cursor */
652 int error;
653 xfs_agblock_t fbno; /* start block of found extent */
654 xfs_extlen_t flen; /* length of found extent */
655 xfs_agblock_t tbno; /* start block of trimmed extent */
656 xfs_extlen_t tlen; /* length of trimmed extent */
657 xfs_agblock_t tend; /* end block of trimmed extent */
658 int i; /* success/failure of operation */
659
660 ASSERT(args->alignment == 1);
661
662 /*
663 * Allocate/initialize a cursor for the by-number freespace btree.
664 */
665 bno_cur = xfs_allocbt_init_cursor(args->mp, args->tp, args->agbp,
666 args->agno, XFS_BTNUM_BNO);
667
668 /*
669 * Lookup bno and minlen in the btree (minlen is irrelevant, really).
670 * Look for the closest free block <= bno, it must contain bno
671 * if any free block does.
672 */
673 error = xfs_alloc_lookup_le(bno_cur, args->agbno, args->minlen, &i);
674 if (error)
675 goto error0;
676 if (!i)
677 goto not_found;
678
679 /*
680 * Grab the freespace record.
681 */
682 error = xfs_alloc_get_rec(bno_cur, &fbno, &flen, &i);
683 if (error)
684 goto error0;
685 XFS_WANT_CORRUPTED_GOTO(i == 1, error0);
686 ASSERT(fbno <= args->agbno);
687
688 /*
689 * Check for overlapping busy extents.
690 */
691 xfs_extent_busy_trim(args, fbno, flen, &tbno, &tlen);
692
693 /*
694 * Give up if the start of the extent is busy, or the freespace isn't
695 * long enough for the minimum request.
696 */
697 if (tbno > args->agbno)
698 goto not_found;
699 if (tlen < args->minlen)
700 goto not_found;
701 tend = tbno + tlen;
702 if (tend < args->agbno + args->minlen)
703 goto not_found;
704
705 /*
706 * End of extent will be smaller of the freespace end and the
707 * maximal requested end.
708 *
709 * Fix the length according to mod and prod if given.
710 */
711 args->len = XFS_AGBLOCK_MIN(tend, args->agbno + args->maxlen)
712 - args->agbno;
713 xfs_alloc_fix_len(args);
714 if (!xfs_alloc_fix_minleft(args))
715 goto not_found;
716
717 ASSERT(args->agbno + args->len <= tend);
718
719 /*
720 * We are allocating agbno for args->len
721 * Allocate/initialize a cursor for the by-size btree.
722 */
723 cnt_cur = xfs_allocbt_init_cursor(args->mp, args->tp, args->agbp,
724 args->agno, XFS_BTNUM_CNT);
725 ASSERT(args->agbno + args->len <=
726 be32_to_cpu(XFS_BUF_TO_AGF(args->agbp)->agf_length));
727 error = xfs_alloc_fixup_trees(cnt_cur, bno_cur, fbno, flen, args->agbno,
728 args->len, XFSA_FIXUP_BNO_OK);
729 if (error) {
730 xfs_btree_del_cursor(cnt_cur, XFS_BTREE_ERROR);
731 goto error0;
732 }
733
734 xfs_btree_del_cursor(bno_cur, XFS_BTREE_NOERROR);
735 xfs_btree_del_cursor(cnt_cur, XFS_BTREE_NOERROR);
736
737 args->wasfromfl = 0;
738 trace_xfs_alloc_exact_done(args);
739 return 0;
740
741 not_found:
742 /* Didn't find it, return null. */
743 xfs_btree_del_cursor(bno_cur, XFS_BTREE_NOERROR);
744 args->agbno = NULLAGBLOCK;
745 trace_xfs_alloc_exact_notfound(args);
746 return 0;
747
748 error0:
749 xfs_btree_del_cursor(bno_cur, XFS_BTREE_ERROR);
750 trace_xfs_alloc_exact_error(args);
751 return error;
752 }
753
754 /*
755 * Search the btree in a given direction via the search cursor and compare
756 * the records found against the good extent we've already found.
757 */
758 STATIC int
759 xfs_alloc_find_best_extent(
760 struct xfs_alloc_arg *args, /* allocation argument structure */
761 struct xfs_btree_cur **gcur, /* good cursor */
762 struct xfs_btree_cur **scur, /* searching cursor */
763 xfs_agblock_t gdiff, /* difference for search comparison */
764 xfs_agblock_t *sbno, /* extent found by search */
765 xfs_extlen_t *slen, /* extent length */
766 xfs_agblock_t *sbnoa, /* aligned extent found by search */
767 xfs_extlen_t *slena, /* aligned extent length */
768 int dir) /* 0 = search right, 1 = search left */
769 {
770 xfs_agblock_t new;
771 xfs_agblock_t sdiff;
772 int error;
773 int i;
774
775 /* The good extent is perfect, no need to search. */
776 if (!gdiff)
777 goto out_use_good;
778
779 /*
780 * Look until we find a better one, run out of space or run off the end.
781 */
782 do {
783 error = xfs_alloc_get_rec(*scur, sbno, slen, &i);
784 if (error)
785 goto error0;
786 XFS_WANT_CORRUPTED_GOTO(i == 1, error0);
787 xfs_alloc_compute_aligned(args, *sbno, *slen, sbnoa, slena);
788
789 /*
790 * The good extent is closer than this one.
791 */
792 if (!dir) {
793 if (*sbnoa >= args->agbno + gdiff)
794 goto out_use_good;
795 } else {
796 if (*sbnoa <= args->agbno - gdiff)
797 goto out_use_good;
798 }
799
800 /*
801 * Same distance, compare length and pick the best.
802 */
803 if (*slena >= args->minlen) {
804 args->len = XFS_EXTLEN_MIN(*slena, args->maxlen);
805 xfs_alloc_fix_len(args);
806
807 sdiff = xfs_alloc_compute_diff(args->agbno, args->len,
808 args->alignment, *sbnoa,
809 *slena, &new);
810
811 /*
812 * Choose closer size and invalidate other cursor.
813 */
814 if (sdiff < gdiff)
815 goto out_use_search;
816 goto out_use_good;
817 }
818
819 if (!dir)
820 error = xfs_btree_increment(*scur, 0, &i);
821 else
822 error = xfs_btree_decrement(*scur, 0, &i);
823 if (error)
824 goto error0;
825 } while (i);
826
827 out_use_good:
828 xfs_btree_del_cursor(*scur, XFS_BTREE_NOERROR);
829 *scur = NULL;
830 return 0;
831
832 out_use_search:
833 xfs_btree_del_cursor(*gcur, XFS_BTREE_NOERROR);
834 *gcur = NULL;
835 return 0;
836
837 error0:
838 /* caller invalidates cursors */
839 return error;
840 }
841
842 /*
843 * Allocate a variable extent near bno in the allocation group agno.
844 * Extent's length (returned in len) will be between minlen and maxlen,
845 * and of the form k * prod + mod unless there's nothing that large.
846 * Return the starting a.g. block, or NULLAGBLOCK if we can't do it.
847 */
848 STATIC int /* error */
849 xfs_alloc_ag_vextent_near(
850 xfs_alloc_arg_t *args) /* allocation argument structure */
851 {
852 xfs_btree_cur_t *bno_cur_gt; /* cursor for bno btree, right side */
853 xfs_btree_cur_t *bno_cur_lt; /* cursor for bno btree, left side */
854 xfs_btree_cur_t *cnt_cur; /* cursor for count btree */
855 xfs_agblock_t gtbno; /* start bno of right side entry */
856 xfs_agblock_t gtbnoa; /* aligned ... */
857 xfs_extlen_t gtdiff; /* difference to right side entry */
858 xfs_extlen_t gtlen; /* length of right side entry */
859 xfs_extlen_t gtlena; /* aligned ... */
860 xfs_agblock_t gtnew; /* useful start bno of right side */
861 int error; /* error code */
862 int i; /* result code, temporary */
863 int j; /* result code, temporary */
864 xfs_agblock_t ltbno; /* start bno of left side entry */
865 xfs_agblock_t ltbnoa; /* aligned ... */
866 xfs_extlen_t ltdiff; /* difference to left side entry */
867 xfs_extlen_t ltlen; /* length of left side entry */
868 xfs_extlen_t ltlena; /* aligned ... */
869 xfs_agblock_t ltnew; /* useful start bno of left side */
870 xfs_extlen_t rlen; /* length of returned extent */
871 int forced = 0;
872 #if defined(DEBUG) && defined(__KERNEL__)
873 /*
874 * Randomly don't execute the first algorithm.
875 */
876 int dofirst; /* set to do first algorithm */
877
878 dofirst = prandom_u32() & 1;
879 #endif
880
881 restart:
882 bno_cur_lt = NULL;
883 bno_cur_gt = NULL;
884 ltlen = 0;
885 gtlena = 0;
886 ltlena = 0;
887
888 /*
889 * Get a cursor for the by-size btree.
890 */
891 cnt_cur = xfs_allocbt_init_cursor(args->mp, args->tp, args->agbp,
892 args->agno, XFS_BTNUM_CNT);
893
894 /*
895 * See if there are any free extents as big as maxlen.
896 */
897 if ((error = xfs_alloc_lookup_ge(cnt_cur, 0, args->maxlen, &i)))
898 goto error0;
899 /*
900 * If none, then pick up the last entry in the tree unless the
901 * tree is empty.
902 */
903 if (!i) {
904 if ((error = xfs_alloc_ag_vextent_small(args, cnt_cur, &ltbno,
905 &ltlen, &i)))
906 goto error0;
907 if (i == 0 || ltlen == 0) {
908 xfs_btree_del_cursor(cnt_cur, XFS_BTREE_NOERROR);
909 trace_xfs_alloc_near_noentry(args);
910 return 0;
911 }
912 ASSERT(i == 1);
913 }
914 args->wasfromfl = 0;
915
916 /*
917 * First algorithm.
918 * If the requested extent is large wrt the freespaces available
919 * in this a.g., then the cursor will be pointing to a btree entry
920 * near the right edge of the tree. If it's in the last btree leaf
921 * block, then we just examine all the entries in that block
922 * that are big enough, and pick the best one.
923 * This is written as a while loop so we can break out of it,
924 * but we never loop back to the top.
925 */
926 while (xfs_btree_islastblock(cnt_cur, 0)) {
927 xfs_extlen_t bdiff;
928 int besti=0;
929 xfs_extlen_t blen=0;
930 xfs_agblock_t bnew=0;
931
932 #if defined(DEBUG) && defined(__KERNEL__)
933 if (!dofirst)
934 break;
935 #endif
936 /*
937 * Start from the entry that lookup found, sequence through
938 * all larger free blocks. If we're actually pointing at a
939 * record smaller than maxlen, go to the start of this block,
940 * and skip all those smaller than minlen.
941 */
942 if (ltlen || args->alignment > 1) {
943 cnt_cur->bc_ptrs[0] = 1;
944 do {
945 if ((error = xfs_alloc_get_rec(cnt_cur, &ltbno,
946 &ltlen, &i)))
947 goto error0;
948 XFS_WANT_CORRUPTED_GOTO(i == 1, error0);
949 if (ltlen >= args->minlen)
950 break;
951 if ((error = xfs_btree_increment(cnt_cur, 0, &i)))
952 goto error0;
953 } while (i);
954 ASSERT(ltlen >= args->minlen);
955 if (!i)
956 break;
957 }
958 i = cnt_cur->bc_ptrs[0];
959 for (j = 1, blen = 0, bdiff = 0;
960 !error && j && (blen < args->maxlen || bdiff > 0);
961 error = xfs_btree_increment(cnt_cur, 0, &j)) {
962 /*
963 * For each entry, decide if it's better than
964 * the previous best entry.
965 */
966 if ((error = xfs_alloc_get_rec(cnt_cur, &ltbno, &ltlen, &i)))
967 goto error0;
968 XFS_WANT_CORRUPTED_GOTO(i == 1, error0);
969 xfs_alloc_compute_aligned(args, ltbno, ltlen,
970 &ltbnoa, &ltlena);
971 if (ltlena < args->minlen)
972 continue;
973 args->len = XFS_EXTLEN_MIN(ltlena, args->maxlen);
974 xfs_alloc_fix_len(args);
975 ASSERT(args->len >= args->minlen);
976 if (args->len < blen)
977 continue;
978 ltdiff = xfs_alloc_compute_diff(args->agbno, args->len,
979 args->alignment, ltbnoa, ltlena, &ltnew);
980 if (ltnew != NULLAGBLOCK &&
981 (args->len > blen || ltdiff < bdiff)) {
982 bdiff = ltdiff;
983 bnew = ltnew;
984 blen = args->len;
985 besti = cnt_cur->bc_ptrs[0];
986 }
987 }
988 /*
989 * It didn't work. We COULD be in a case where
990 * there's a good record somewhere, so try again.
991 */
992 if (blen == 0)
993 break;
994 /*
995 * Point at the best entry, and retrieve it again.
996 */
997 cnt_cur->bc_ptrs[0] = besti;
998 if ((error = xfs_alloc_get_rec(cnt_cur, &ltbno, &ltlen, &i)))
999 goto error0;
1000 XFS_WANT_CORRUPTED_GOTO(i == 1, error0);
1001 ASSERT(ltbno + ltlen <= be32_to_cpu(XFS_BUF_TO_AGF(args->agbp)->agf_length));
1002 args->len = blen;
1003 if (!xfs_alloc_fix_minleft(args)) {
1004 xfs_btree_del_cursor(cnt_cur, XFS_BTREE_NOERROR);
1005 trace_xfs_alloc_near_nominleft(args);
1006 return 0;
1007 }
1008 blen = args->len;
1009 /*
1010 * We are allocating starting at bnew for blen blocks.
1011 */
1012 args->agbno = bnew;
1013 ASSERT(bnew >= ltbno);
1014 ASSERT(bnew + blen <= ltbno + ltlen);
1015 /*
1016 * Set up a cursor for the by-bno tree.
1017 */
1018 bno_cur_lt = xfs_allocbt_init_cursor(args->mp, args->tp,
1019 args->agbp, args->agno, XFS_BTNUM_BNO);
1020 /*
1021 * Fix up the btree entries.
1022 */
1023 if ((error = xfs_alloc_fixup_trees(cnt_cur, bno_cur_lt, ltbno,
1024 ltlen, bnew, blen, XFSA_FIXUP_CNT_OK)))
1025 goto error0;
1026 xfs_btree_del_cursor(cnt_cur, XFS_BTREE_NOERROR);
1027 xfs_btree_del_cursor(bno_cur_lt, XFS_BTREE_NOERROR);
1028
1029 trace_xfs_alloc_near_first(args);
1030 return 0;
1031 }
1032 /*
1033 * Second algorithm.
1034 * Search in the by-bno tree to the left and to the right
1035 * simultaneously, until in each case we find a space big enough,
1036 * or run into the edge of the tree. When we run into the edge,
1037 * we deallocate that cursor.
1038 * If both searches succeed, we compare the two spaces and pick
1039 * the better one.
1040 * With alignment, it's possible for both to fail; the upper
1041 * level algorithm that picks allocation groups for allocations
1042 * is not supposed to do this.
1043 */
1044 /*
1045 * Allocate and initialize the cursor for the leftward search.
1046 */
1047 bno_cur_lt = xfs_allocbt_init_cursor(args->mp, args->tp, args->agbp,
1048 args->agno, XFS_BTNUM_BNO);
1049 /*
1050 * Lookup <= bno to find the leftward search's starting point.
1051 */
1052 if ((error = xfs_alloc_lookup_le(bno_cur_lt, args->agbno, args->maxlen, &i)))
1053 goto error0;
1054 if (!i) {
1055 /*
1056 * Didn't find anything; use this cursor for the rightward
1057 * search.
1058 */
1059 bno_cur_gt = bno_cur_lt;
1060 bno_cur_lt = NULL;
1061 }
1062 /*
1063 * Found something. Duplicate the cursor for the rightward search.
1064 */
1065 else if ((error = xfs_btree_dup_cursor(bno_cur_lt, &bno_cur_gt)))
1066 goto error0;
1067 /*
1068 * Increment the cursor, so we will point at the entry just right
1069 * of the leftward entry if any, or to the leftmost entry.
1070 */
1071 if ((error = xfs_btree_increment(bno_cur_gt, 0, &i)))
1072 goto error0;
1073 if (!i) {
1074 /*
1075 * It failed, there are no rightward entries.
1076 */
1077 xfs_btree_del_cursor(bno_cur_gt, XFS_BTREE_NOERROR);
1078 bno_cur_gt = NULL;
1079 }
1080 /*
1081 * Loop going left with the leftward cursor, right with the
1082 * rightward cursor, until either both directions give up or
1083 * we find an entry at least as big as minlen.
1084 */
1085 do {
1086 if (bno_cur_lt) {
1087 if ((error = xfs_alloc_get_rec(bno_cur_lt, &ltbno, &ltlen, &i)))
1088 goto error0;
1089 XFS_WANT_CORRUPTED_GOTO(i == 1, error0);
1090 xfs_alloc_compute_aligned(args, ltbno, ltlen,
1091 &ltbnoa, &ltlena);
1092 if (ltlena >= args->minlen)
1093 break;
1094 if ((error = xfs_btree_decrement(bno_cur_lt, 0, &i)))
1095 goto error0;
1096 if (!i) {
1097 xfs_btree_del_cursor(bno_cur_lt,
1098 XFS_BTREE_NOERROR);
1099 bno_cur_lt = NULL;
1100 }
1101 }
1102 if (bno_cur_gt) {
1103 if ((error = xfs_alloc_get_rec(bno_cur_gt, &gtbno, &gtlen, &i)))
1104 goto error0;
1105 XFS_WANT_CORRUPTED_GOTO(i == 1, error0);
1106 xfs_alloc_compute_aligned(args, gtbno, gtlen,
1107 &gtbnoa, &gtlena);
1108 if (gtlena >= args->minlen)
1109 break;
1110 if ((error = xfs_btree_increment(bno_cur_gt, 0, &i)))
1111 goto error0;
1112 if (!i) {
1113 xfs_btree_del_cursor(bno_cur_gt,
1114 XFS_BTREE_NOERROR);
1115 bno_cur_gt = NULL;
1116 }
1117 }
1118 } while (bno_cur_lt || bno_cur_gt);
1119
1120 /*
1121 * Got both cursors still active, need to find better entry.
1122 */
1123 if (bno_cur_lt && bno_cur_gt) {
1124 if (ltlena >= args->minlen) {
1125 /*
1126 * Left side is good, look for a right side entry.
1127 */
1128 args->len = XFS_EXTLEN_MIN(ltlena, args->maxlen);
1129 xfs_alloc_fix_len(args);
1130 ltdiff = xfs_alloc_compute_diff(args->agbno, args->len,
1131 args->alignment, ltbnoa, ltlena, &ltnew);
1132
1133 error = xfs_alloc_find_best_extent(args,
1134 &bno_cur_lt, &bno_cur_gt,
1135 ltdiff, &gtbno, &gtlen,
1136 &gtbnoa, &gtlena,
1137 0 /* search right */);
1138 } else {
1139 ASSERT(gtlena >= args->minlen);
1140
1141 /*
1142 * Right side is good, look for a left side entry.
1143 */
1144 args->len = XFS_EXTLEN_MIN(gtlena, args->maxlen);
1145 xfs_alloc_fix_len(args);
1146 gtdiff = xfs_alloc_compute_diff(args->agbno, args->len,
1147 args->alignment, gtbnoa, gtlena, &gtnew);
1148
1149 error = xfs_alloc_find_best_extent(args,
1150 &bno_cur_gt, &bno_cur_lt,
1151 gtdiff, &ltbno, &ltlen,
1152 &ltbnoa, &ltlena,
1153 1 /* search left */);
1154 }
1155
1156 if (error)
1157 goto error0;
1158 }
1159
1160 /*
1161 * If we couldn't get anything, give up.
1162 */
1163 if (bno_cur_lt == NULL && bno_cur_gt == NULL) {
1164 xfs_btree_del_cursor(cnt_cur, XFS_BTREE_NOERROR);
1165
1166 if (!forced++) {
1167 trace_xfs_alloc_near_busy(args);
1168 xfs_log_force(args->mp, XFS_LOG_SYNC);
1169 goto restart;
1170 }
1171 trace_xfs_alloc_size_neither(args);
1172 args->agbno = NULLAGBLOCK;
1173 return 0;
1174 }
1175
1176 /*
1177 * At this point we have selected a freespace entry, either to the
1178 * left or to the right. If it's on the right, copy all the
1179 * useful variables to the "left" set so we only have one
1180 * copy of this code.
1181 */
1182 if (bno_cur_gt) {
1183 bno_cur_lt = bno_cur_gt;
1184 bno_cur_gt = NULL;
1185 ltbno = gtbno;
1186 ltbnoa = gtbnoa;
1187 ltlen = gtlen;
1188 ltlena = gtlena;
1189 j = 1;
1190 } else
1191 j = 0;
1192
1193 /*
1194 * Fix up the length and compute the useful address.
1195 */
1196 args->len = XFS_EXTLEN_MIN(ltlena, args->maxlen);
1197 xfs_alloc_fix_len(args);
1198 if (!xfs_alloc_fix_minleft(args)) {
1199 trace_xfs_alloc_near_nominleft(args);
1200 xfs_btree_del_cursor(bno_cur_lt, XFS_BTREE_NOERROR);
1201 xfs_btree_del_cursor(cnt_cur, XFS_BTREE_NOERROR);
1202 return 0;
1203 }
1204 rlen = args->len;
1205 (void)xfs_alloc_compute_diff(args->agbno, rlen, args->alignment,
1206 ltbnoa, ltlena, &ltnew);
1207 ASSERT(ltnew >= ltbno);
1208 ASSERT(ltnew + rlen <= ltbnoa + ltlena);
1209 ASSERT(ltnew + rlen <= be32_to_cpu(XFS_BUF_TO_AGF(args->agbp)->agf_length));
1210 args->agbno = ltnew;
1211
1212 if ((error = xfs_alloc_fixup_trees(cnt_cur, bno_cur_lt, ltbno, ltlen,
1213 ltnew, rlen, XFSA_FIXUP_BNO_OK)))
1214 goto error0;
1215
1216 if (j)
1217 trace_xfs_alloc_near_greater(args);
1218 else
1219 trace_xfs_alloc_near_lesser(args);
1220
1221 xfs_btree_del_cursor(cnt_cur, XFS_BTREE_NOERROR);
1222 xfs_btree_del_cursor(bno_cur_lt, XFS_BTREE_NOERROR);
1223 return 0;
1224
1225 error0:
1226 trace_xfs_alloc_near_error(args);
1227 if (cnt_cur != NULL)
1228 xfs_btree_del_cursor(cnt_cur, XFS_BTREE_ERROR);
1229 if (bno_cur_lt != NULL)
1230 xfs_btree_del_cursor(bno_cur_lt, XFS_BTREE_ERROR);
1231 if (bno_cur_gt != NULL)
1232 xfs_btree_del_cursor(bno_cur_gt, XFS_BTREE_ERROR);
1233 return error;
1234 }
1235
1236 /*
1237 * Allocate a variable extent anywhere in the allocation group agno.
1238 * Extent's length (returned in len) will be between minlen and maxlen,
1239 * and of the form k * prod + mod unless there's nothing that large.
1240 * Return the starting a.g. block, or NULLAGBLOCK if we can't do it.
1241 */
1242 STATIC int /* error */
1243 xfs_alloc_ag_vextent_size(
1244 xfs_alloc_arg_t *args) /* allocation argument structure */
1245 {
1246 xfs_btree_cur_t *bno_cur; /* cursor for bno btree */
1247 xfs_btree_cur_t *cnt_cur; /* cursor for cnt btree */
1248 int error; /* error result */
1249 xfs_agblock_t fbno; /* start of found freespace */
1250 xfs_extlen_t flen; /* length of found freespace */
1251 int i; /* temp status variable */
1252 xfs_agblock_t rbno; /* returned block number */
1253 xfs_extlen_t rlen; /* length of returned extent */
1254 int forced = 0;
1255
1256 restart:
1257 /*
1258 * Allocate and initialize a cursor for the by-size btree.
1259 */
1260 cnt_cur = xfs_allocbt_init_cursor(args->mp, args->tp, args->agbp,
1261 args->agno, XFS_BTNUM_CNT);
1262 bno_cur = NULL;
1263
1264 /*
1265 * Look for an entry >= maxlen+alignment-1 blocks.
1266 */
1267 if ((error = xfs_alloc_lookup_ge(cnt_cur, 0,
1268 args->maxlen + args->alignment - 1, &i)))
1269 goto error0;
1270
1271 /*
1272 * If none or we have busy extents that we cannot allocate from, then
1273 * we have to settle for a smaller extent. In the case that there are
1274 * no large extents, this will return the last entry in the tree unless
1275 * the tree is empty. In the case that there are only busy large
1276 * extents, this will return the largest small extent unless there
1277 * are no smaller extents available.
1278 */
1279 if (!i || forced > 1) {
1280 error = xfs_alloc_ag_vextent_small(args, cnt_cur,
1281 &fbno, &flen, &i);
1282 if (error)
1283 goto error0;
1284 if (i == 0 || flen == 0) {
1285 xfs_btree_del_cursor(cnt_cur, XFS_BTREE_NOERROR);
1286 trace_xfs_alloc_size_noentry(args);
1287 return 0;
1288 }
1289 ASSERT(i == 1);
1290 xfs_alloc_compute_aligned(args, fbno, flen, &rbno, &rlen);
1291 } else {
1292 /*
1293 * Search for a non-busy extent that is large enough.
1294 * If we are at low space, don't check, or if we fall of
1295 * the end of the btree, turn off the busy check and
1296 * restart.
1297 */
1298 for (;;) {
1299 error = xfs_alloc_get_rec(cnt_cur, &fbno, &flen, &i);
1300 if (error)
1301 goto error0;
1302 XFS_WANT_CORRUPTED_GOTO(i == 1, error0);
1303
1304 xfs_alloc_compute_aligned(args, fbno, flen,
1305 &rbno, &rlen);
1306
1307 if (rlen >= args->maxlen)
1308 break;
1309
1310 error = xfs_btree_increment(cnt_cur, 0, &i);
1311 if (error)
1312 goto error0;
1313 if (i == 0) {
1314 /*
1315 * Our only valid extents must have been busy.
1316 * Make it unbusy by forcing the log out and
1317 * retrying. If we've been here before, forcing
1318 * the log isn't making the extents available,
1319 * which means they have probably been freed in
1320 * this transaction. In that case, we have to
1321 * give up on them and we'll attempt a minlen
1322 * allocation the next time around.
1323 */
1324 xfs_btree_del_cursor(cnt_cur,
1325 XFS_BTREE_NOERROR);
1326 trace_xfs_alloc_size_busy(args);
1327 if (!forced++)
1328 xfs_log_force(args->mp, XFS_LOG_SYNC);
1329 goto restart;
1330 }
1331 }
1332 }
1333
1334 /*
1335 * In the first case above, we got the last entry in the
1336 * by-size btree. Now we check to see if the space hits maxlen
1337 * once aligned; if not, we search left for something better.
1338 * This can't happen in the second case above.
1339 */
1340 rlen = XFS_EXTLEN_MIN(args->maxlen, rlen);
1341 XFS_WANT_CORRUPTED_GOTO(rlen == 0 ||
1342 (rlen <= flen && rbno + rlen <= fbno + flen), error0);
1343 if (rlen < args->maxlen) {
1344 xfs_agblock_t bestfbno;
1345 xfs_extlen_t bestflen;
1346 xfs_agblock_t bestrbno;
1347 xfs_extlen_t bestrlen;
1348
1349 bestrlen = rlen;
1350 bestrbno = rbno;
1351 bestflen = flen;
1352 bestfbno = fbno;
1353 for (;;) {
1354 if ((error = xfs_btree_decrement(cnt_cur, 0, &i)))
1355 goto error0;
1356 if (i == 0)
1357 break;
1358 if ((error = xfs_alloc_get_rec(cnt_cur, &fbno, &flen,
1359 &i)))
1360 goto error0;
1361 XFS_WANT_CORRUPTED_GOTO(i == 1, error0);
1362 if (flen < bestrlen)
1363 break;
1364 xfs_alloc_compute_aligned(args, fbno, flen,
1365 &rbno, &rlen);
1366 rlen = XFS_EXTLEN_MIN(args->maxlen, rlen);
1367 XFS_WANT_CORRUPTED_GOTO(rlen == 0 ||
1368 (rlen <= flen && rbno + rlen <= fbno + flen),
1369 error0);
1370 if (rlen > bestrlen) {
1371 bestrlen = rlen;
1372 bestrbno = rbno;
1373 bestflen = flen;
1374 bestfbno = fbno;
1375 if (rlen == args->maxlen)
1376 break;
1377 }
1378 }
1379 if ((error = xfs_alloc_lookup_eq(cnt_cur, bestfbno, bestflen,
1380 &i)))
1381 goto error0;
1382 XFS_WANT_CORRUPTED_GOTO(i == 1, error0);
1383 rlen = bestrlen;
1384 rbno = bestrbno;
1385 flen = bestflen;
1386 fbno = bestfbno;
1387 }
1388 args->wasfromfl = 0;
1389 /*
1390 * Fix up the length.
1391 */
1392 args->len = rlen;
1393 if (rlen < args->minlen) {
1394 if (!forced++) {
1395 xfs_btree_del_cursor(cnt_cur, XFS_BTREE_NOERROR);
1396 trace_xfs_alloc_size_busy(args);
1397 xfs_log_force(args->mp, XFS_LOG_SYNC);
1398 goto restart;
1399 }
1400 goto out_nominleft;
1401 }
1402 xfs_alloc_fix_len(args);
1403
1404 if (!xfs_alloc_fix_minleft(args))
1405 goto out_nominleft;
1406 rlen = args->len;
1407 XFS_WANT_CORRUPTED_GOTO(rlen <= flen, error0);
1408 /*
1409 * Allocate and initialize a cursor for the by-block tree.
1410 */
1411 bno_cur = xfs_allocbt_init_cursor(args->mp, args->tp, args->agbp,
1412 args->agno, XFS_BTNUM_BNO);
1413 if ((error = xfs_alloc_fixup_trees(cnt_cur, bno_cur, fbno, flen,
1414 rbno, rlen, XFSA_FIXUP_CNT_OK)))
1415 goto error0;
1416 xfs_btree_del_cursor(cnt_cur, XFS_BTREE_NOERROR);
1417 xfs_btree_del_cursor(bno_cur, XFS_BTREE_NOERROR);
1418 cnt_cur = bno_cur = NULL;
1419 args->len = rlen;
1420 args->agbno = rbno;
1421 XFS_WANT_CORRUPTED_GOTO(
1422 args->agbno + args->len <=
1423 be32_to_cpu(XFS_BUF_TO_AGF(args->agbp)->agf_length),
1424 error0);
1425 trace_xfs_alloc_size_done(args);
1426 return 0;
1427
1428 error0:
1429 trace_xfs_alloc_size_error(args);
1430 if (cnt_cur)
1431 xfs_btree_del_cursor(cnt_cur, XFS_BTREE_ERROR);
1432 if (bno_cur)
1433 xfs_btree_del_cursor(bno_cur, XFS_BTREE_ERROR);
1434 return error;
1435
1436 out_nominleft:
1437 xfs_btree_del_cursor(cnt_cur, XFS_BTREE_NOERROR);
1438 trace_xfs_alloc_size_nominleft(args);
1439 args->agbno = NULLAGBLOCK;
1440 return 0;
1441 }
1442
1443 /*
1444 * Deal with the case where only small freespaces remain.
1445 * Either return the contents of the last freespace record,
1446 * or allocate space from the freelist if there is nothing in the tree.
1447 */
1448 STATIC int /* error */
1449 xfs_alloc_ag_vextent_small(
1450 xfs_alloc_arg_t *args, /* allocation argument structure */
1451 xfs_btree_cur_t *ccur, /* by-size cursor */
1452 xfs_agblock_t *fbnop, /* result block number */
1453 xfs_extlen_t *flenp, /* result length */
1454 int *stat) /* status: 0-freelist, 1-normal/none */
1455 {
1456 int error;
1457 xfs_agblock_t fbno;
1458 xfs_extlen_t flen;
1459 int i;
1460
1461 if ((error = xfs_btree_decrement(ccur, 0, &i)))
1462 goto error0;
1463 if (i) {
1464 if ((error = xfs_alloc_get_rec(ccur, &fbno, &flen, &i)))
1465 goto error0;
1466 XFS_WANT_CORRUPTED_GOTO(i == 1, error0);
1467 }
1468 /*
1469 * Nothing in the btree, try the freelist. Make sure
1470 * to respect minleft even when pulling from the
1471 * freelist.
1472 */
1473 else if (args->minlen == 1 && args->alignment == 1 && !args->isfl &&
1474 (be32_to_cpu(XFS_BUF_TO_AGF(args->agbp)->agf_flcount)
1475 > args->minleft)) {
1476 error = xfs_alloc_get_freelist(args->tp, args->agbp, &fbno, 0);
1477 if (error)
1478 goto error0;
1479 if (fbno != NULLAGBLOCK) {
1480 xfs_extent_busy_reuse(args->mp, args->agno, fbno, 1,
1481 args->userdata);
1482
1483 if (args->userdata) {
1484 xfs_buf_t *bp;
1485
1486 bp = xfs_btree_get_bufs(args->mp, args->tp,
1487 args->agno, fbno, 0);
1488 xfs_trans_binval(args->tp, bp);
1489 }
1490 args->len = 1;
1491 args->agbno = fbno;
1492 XFS_WANT_CORRUPTED_GOTO(
1493 args->agbno + args->len <=
1494 be32_to_cpu(XFS_BUF_TO_AGF(args->agbp)->agf_length),
1495 error0);
1496 args->wasfromfl = 1;
1497 trace_xfs_alloc_small_freelist(args);
1498 *stat = 0;
1499 return 0;
1500 }
1501 /*
1502 * Nothing in the freelist.
1503 */
1504 else
1505 flen = 0;
1506 }
1507 /*
1508 * Can't allocate from the freelist for some reason.
1509 */
1510 else {
1511 fbno = NULLAGBLOCK;
1512 flen = 0;
1513 }
1514 /*
1515 * Can't do the allocation, give up.
1516 */
1517 if (flen < args->minlen) {
1518 args->agbno = NULLAGBLOCK;
1519 trace_xfs_alloc_small_notenough(args);
1520 flen = 0;
1521 }
1522 *fbnop = fbno;
1523 *flenp = flen;
1524 *stat = 1;
1525 trace_xfs_alloc_small_done(args);
1526 return 0;
1527
1528 error0:
1529 trace_xfs_alloc_small_error(args);
1530 return error;
1531 }
1532
1533 /*
1534 * Free the extent starting at agno/bno for length.
1535 */
1536 STATIC int /* error */
1537 xfs_free_ag_extent(
1538 xfs_trans_t *tp, /* transaction pointer */
1539 xfs_buf_t *agbp, /* buffer for a.g. freelist header */
1540 xfs_agnumber_t agno, /* allocation group number */
1541 xfs_agblock_t bno, /* starting block number */
1542 xfs_extlen_t len, /* length of extent */
1543 int isfl) /* set if is freelist blocks - no sb acctg */
1544 {
1545 xfs_btree_cur_t *bno_cur; /* cursor for by-block btree */
1546 xfs_btree_cur_t *cnt_cur; /* cursor for by-size btree */
1547 int error; /* error return value */
1548 xfs_agblock_t gtbno; /* start of right neighbor block */
1549 xfs_extlen_t gtlen; /* length of right neighbor block */
1550 int haveleft; /* have a left neighbor block */
1551 int haveright; /* have a right neighbor block */
1552 int i; /* temp, result code */
1553 xfs_agblock_t ltbno; /* start of left neighbor block */
1554 xfs_extlen_t ltlen; /* length of left neighbor block */
1555 xfs_mount_t *mp; /* mount point struct for filesystem */
1556 xfs_agblock_t nbno; /* new starting block of freespace */
1557 xfs_extlen_t nlen; /* new length of freespace */
1558 xfs_perag_t *pag; /* per allocation group data */
1559
1560 mp = tp->t_mountp;
1561 /*
1562 * Allocate and initialize a cursor for the by-block btree.
1563 */
1564 bno_cur = xfs_allocbt_init_cursor(mp, tp, agbp, agno, XFS_BTNUM_BNO);
1565 cnt_cur = NULL;
1566 /*
1567 * Look for a neighboring block on the left (lower block numbers)
1568 * that is contiguous with this space.
1569 */
1570 if ((error = xfs_alloc_lookup_le(bno_cur, bno, len, &haveleft)))
1571 goto error0;
1572 if (haveleft) {
1573 /*
1574 * There is a block to our left.
1575 */
1576 if ((error = xfs_alloc_get_rec(bno_cur, &ltbno, &ltlen, &i)))
1577 goto error0;
1578 XFS_WANT_CORRUPTED_GOTO(i == 1, error0);
1579 /*
1580 * It's not contiguous, though.
1581 */
1582 if (ltbno + ltlen < bno)
1583 haveleft = 0;
1584 else {
1585 /*
1586 * If this failure happens the request to free this
1587 * space was invalid, it's (partly) already free.
1588 * Very bad.
1589 */
1590 XFS_WANT_CORRUPTED_GOTO(ltbno + ltlen <= bno, error0);
1591 }
1592 }
1593 /*
1594 * Look for a neighboring block on the right (higher block numbers)
1595 * that is contiguous with this space.
1596 */
1597 if ((error = xfs_btree_increment(bno_cur, 0, &haveright)))
1598 goto error0;
1599 if (haveright) {
1600 /*
1601 * There is a block to our right.
1602 */
1603 if ((error = xfs_alloc_get_rec(bno_cur, &gtbno, &gtlen, &i)))
1604 goto error0;
1605 XFS_WANT_CORRUPTED_GOTO(i == 1, error0);
1606 /*
1607 * It's not contiguous, though.
1608 */
1609 if (bno + len < gtbno)
1610 haveright = 0;
1611 else {
1612 /*
1613 * If this failure happens the request to free this
1614 * space was invalid, it's (partly) already free.
1615 * Very bad.
1616 */
1617 XFS_WANT_CORRUPTED_GOTO(gtbno >= bno + len, error0);
1618 }
1619 }
1620 /*
1621 * Now allocate and initialize a cursor for the by-size tree.
1622 */
1623 cnt_cur = xfs_allocbt_init_cursor(mp, tp, agbp, agno, XFS_BTNUM_CNT);
1624 /*
1625 * Have both left and right contiguous neighbors.
1626 * Merge all three into a single free block.
1627 */
1628 if (haveleft && haveright) {
1629 /*
1630 * Delete the old by-size entry on the left.
1631 */
1632 if ((error = xfs_alloc_lookup_eq(cnt_cur, ltbno, ltlen, &i)))
1633 goto error0;
1634 XFS_WANT_CORRUPTED_GOTO(i == 1, error0);
1635 if ((error = xfs_btree_delete(cnt_cur, &i)))
1636 goto error0;
1637 XFS_WANT_CORRUPTED_GOTO(i == 1, error0);
1638 /*
1639 * Delete the old by-size entry on the right.
1640 */
1641 if ((error = xfs_alloc_lookup_eq(cnt_cur, gtbno, gtlen, &i)))
1642 goto error0;
1643 XFS_WANT_CORRUPTED_GOTO(i == 1, error0);
1644 if ((error = xfs_btree_delete(cnt_cur, &i)))
1645 goto error0;
1646 XFS_WANT_CORRUPTED_GOTO(i == 1, error0);
1647 /*
1648 * Delete the old by-block entry for the right block.
1649 */
1650 if ((error = xfs_btree_delete(bno_cur, &i)))
1651 goto error0;
1652 XFS_WANT_CORRUPTED_GOTO(i == 1, error0);
1653 /*
1654 * Move the by-block cursor back to the left neighbor.
1655 */
1656 if ((error = xfs_btree_decrement(bno_cur, 0, &i)))
1657 goto error0;
1658 XFS_WANT_CORRUPTED_GOTO(i == 1, error0);
1659 #ifdef DEBUG
1660 /*
1661 * Check that this is the right record: delete didn't
1662 * mangle the cursor.
1663 */
1664 {
1665 xfs_agblock_t xxbno;
1666 xfs_extlen_t xxlen;
1667
1668 if ((error = xfs_alloc_get_rec(bno_cur, &xxbno, &xxlen,
1669 &i)))
1670 goto error0;
1671 XFS_WANT_CORRUPTED_GOTO(
1672 i == 1 && xxbno == ltbno && xxlen == ltlen,
1673 error0);
1674 }
1675 #endif
1676 /*
1677 * Update remaining by-block entry to the new, joined block.
1678 */
1679 nbno = ltbno;
1680 nlen = len + ltlen + gtlen;
1681 if ((error = xfs_alloc_update(bno_cur, nbno, nlen)))
1682 goto error0;
1683 }
1684 /*
1685 * Have only a left contiguous neighbor.
1686 * Merge it together with the new freespace.
1687 */
1688 else if (haveleft) {
1689 /*
1690 * Delete the old by-size entry on the left.
1691 */
1692 if ((error = xfs_alloc_lookup_eq(cnt_cur, ltbno, ltlen, &i)))
1693 goto error0;
1694 XFS_WANT_CORRUPTED_GOTO(i == 1, error0);
1695 if ((error = xfs_btree_delete(cnt_cur, &i)))
1696 goto error0;
1697 XFS_WANT_CORRUPTED_GOTO(i == 1, error0);
1698 /*
1699 * Back up the by-block cursor to the left neighbor, and
1700 * update its length.
1701 */
1702 if ((error = xfs_btree_decrement(bno_cur, 0, &i)))
1703 goto error0;
1704 XFS_WANT_CORRUPTED_GOTO(i == 1, error0);
1705 nbno = ltbno;
1706 nlen = len + ltlen;
1707 if ((error = xfs_alloc_update(bno_cur, nbno, nlen)))
1708 goto error0;
1709 }
1710 /*
1711 * Have only a right contiguous neighbor.
1712 * Merge it together with the new freespace.
1713 */
1714 else if (haveright) {
1715 /*
1716 * Delete the old by-size entry on the right.
1717 */
1718 if ((error = xfs_alloc_lookup_eq(cnt_cur, gtbno, gtlen, &i)))
1719 goto error0;
1720 XFS_WANT_CORRUPTED_GOTO(i == 1, error0);
1721 if ((error = xfs_btree_delete(cnt_cur, &i)))
1722 goto error0;
1723 XFS_WANT_CORRUPTED_GOTO(i == 1, error0);
1724 /*
1725 * Update the starting block and length of the right
1726 * neighbor in the by-block tree.
1727 */
1728 nbno = bno;
1729 nlen = len + gtlen;
1730 if ((error = xfs_alloc_update(bno_cur, nbno, nlen)))
1731 goto error0;
1732 }
1733 /*
1734 * No contiguous neighbors.
1735 * Insert the new freespace into the by-block tree.
1736 */
1737 else {
1738 nbno = bno;
1739 nlen = len;
1740 if ((error = xfs_btree_insert(bno_cur, &i)))
1741 goto error0;
1742 XFS_WANT_CORRUPTED_GOTO(i == 1, error0);
1743 }
1744 xfs_btree_del_cursor(bno_cur, XFS_BTREE_NOERROR);
1745 bno_cur = NULL;
1746 /*
1747 * In all cases we need to insert the new freespace in the by-size tree.
1748 */
1749 if ((error = xfs_alloc_lookup_eq(cnt_cur, nbno, nlen, &i)))
1750 goto error0;
1751 XFS_WANT_CORRUPTED_GOTO(i == 0, error0);
1752 if ((error = xfs_btree_insert(cnt_cur, &i)))
1753 goto error0;
1754 XFS_WANT_CORRUPTED_GOTO(i == 1, error0);
1755 xfs_btree_del_cursor(cnt_cur, XFS_BTREE_NOERROR);
1756 cnt_cur = NULL;
1757
1758 /*
1759 * Update the freespace totals in the ag and superblock.
1760 */
1761 pag = xfs_perag_get(mp, agno);
1762 error = xfs_alloc_update_counters(tp, pag, agbp, len);
1763 xfs_perag_put(pag);
1764 if (error)
1765 goto error0;
1766
1767 if (!isfl)
1768 xfs_trans_mod_sb(tp, XFS_TRANS_SB_FDBLOCKS, (long)len);
1769 XFS_STATS_INC(xs_freex);
1770 XFS_STATS_ADD(xs_freeb, len);
1771
1772 trace_xfs_free_extent(mp, agno, bno, len, isfl, haveleft, haveright);
1773
1774 return 0;
1775
1776 error0:
1777 trace_xfs_free_extent(mp, agno, bno, len, isfl, -1, -1);
1778 if (bno_cur)
1779 xfs_btree_del_cursor(bno_cur, XFS_BTREE_ERROR);
1780 if (cnt_cur)
1781 xfs_btree_del_cursor(cnt_cur, XFS_BTREE_ERROR);
1782 return error;
1783 }
1784
1785 /*
1786 * Visible (exported) allocation/free functions.
1787 * Some of these are used just by xfs_alloc_btree.c and this file.
1788 */
1789
1790 /*
1791 * Compute and fill in value of m_ag_maxlevels.
1792 */
1793 void
1794 xfs_alloc_compute_maxlevels(
1795 xfs_mount_t *mp) /* file system mount structure */
1796 {
1797 int level;
1798 uint maxblocks;
1799 uint maxleafents;
1800 int minleafrecs;
1801 int minnoderecs;
1802
1803 maxleafents = (mp->m_sb.sb_agblocks + 1) / 2;
1804 minleafrecs = mp->m_alloc_mnr[0];
1805 minnoderecs = mp->m_alloc_mnr[1];
1806 maxblocks = (maxleafents + minleafrecs - 1) / minleafrecs;
1807 for (level = 1; maxblocks > 1; level++)
1808 maxblocks = (maxblocks + minnoderecs - 1) / minnoderecs;
1809 mp->m_ag_maxlevels = level;
1810 }
1811
1812 /*
1813 * Find the length of the longest extent in an AG.
1814 */
1815 xfs_extlen_t
1816 xfs_alloc_longest_free_extent(
1817 struct xfs_mount *mp,
1818 struct xfs_perag *pag)
1819 {
1820 xfs_extlen_t need, delta = 0;
1821
1822 need = XFS_MIN_FREELIST_PAG(pag, mp);
1823 if (need > pag->pagf_flcount)
1824 delta = need - pag->pagf_flcount;
1825
1826 if (pag->pagf_longest > delta)
1827 return pag->pagf_longest - delta;
1828 return pag->pagf_flcount > 0 || pag->pagf_longest > 0;
1829 }
1830
1831 /*
1832 * Decide whether to use this allocation group for this allocation.
1833 * If so, fix up the btree freelist's size.
1834 */
1835 STATIC int /* error */
1836 xfs_alloc_fix_freelist(
1837 xfs_alloc_arg_t *args, /* allocation argument structure */
1838 int flags) /* XFS_ALLOC_FLAG_... */
1839 {
1840 xfs_buf_t *agbp; /* agf buffer pointer */
1841 xfs_agf_t *agf; /* a.g. freespace structure pointer */
1842 xfs_buf_t *agflbp;/* agfl buffer pointer */
1843 xfs_agblock_t bno; /* freelist block */
1844 xfs_extlen_t delta; /* new blocks needed in freelist */
1845 int error; /* error result code */
1846 xfs_extlen_t longest;/* longest extent in allocation group */
1847 xfs_mount_t *mp; /* file system mount point structure */
1848 xfs_extlen_t need; /* total blocks needed in freelist */
1849 xfs_perag_t *pag; /* per-ag information structure */
1850 xfs_alloc_arg_t targs; /* local allocation arguments */
1851 xfs_trans_t *tp; /* transaction pointer */
1852
1853 mp = args->mp;
1854
1855 pag = args->pag;
1856 tp = args->tp;
1857 if (!pag->pagf_init) {
1858 if ((error = xfs_alloc_read_agf(mp, tp, args->agno, flags,
1859 &agbp)))
1860 return error;
1861 if (!pag->pagf_init) {
1862 ASSERT(flags & XFS_ALLOC_FLAG_TRYLOCK);
1863 ASSERT(!(flags & XFS_ALLOC_FLAG_FREEING));
1864 args->agbp = NULL;
1865 return 0;
1866 }
1867 } else
1868 agbp = NULL;
1869
1870 /*
1871 * If this is a metadata preferred pag and we are user data
1872 * then try somewhere else if we are not being asked to
1873 * try harder at this point
1874 */
1875 if (pag->pagf_metadata && args->userdata &&
1876 (flags & XFS_ALLOC_FLAG_TRYLOCK)) {
1877 ASSERT(!(flags & XFS_ALLOC_FLAG_FREEING));
1878 args->agbp = NULL;
1879 return 0;
1880 }
1881
1882 if (!(flags & XFS_ALLOC_FLAG_FREEING)) {
1883 /*
1884 * If it looks like there isn't a long enough extent, or enough
1885 * total blocks, reject it.
1886 */
1887 need = XFS_MIN_FREELIST_PAG(pag, mp);
1888 longest = xfs_alloc_longest_free_extent(mp, pag);
1889 if ((args->minlen + args->alignment + args->minalignslop - 1) >
1890 longest ||
1891 ((int)(pag->pagf_freeblks + pag->pagf_flcount -
1892 need - args->total) < (int)args->minleft)) {
1893 if (agbp)
1894 xfs_trans_brelse(tp, agbp);
1895 args->agbp = NULL;
1896 return 0;
1897 }
1898 }
1899
1900 /*
1901 * Get the a.g. freespace buffer.
1902 * Can fail if we're not blocking on locks, and it's held.
1903 */
1904 if (agbp == NULL) {
1905 if ((error = xfs_alloc_read_agf(mp, tp, args->agno, flags,
1906 &agbp)))
1907 return error;
1908 if (agbp == NULL) {
1909 ASSERT(flags & XFS_ALLOC_FLAG_TRYLOCK);
1910 ASSERT(!(flags & XFS_ALLOC_FLAG_FREEING));
1911 args->agbp = NULL;
1912 return 0;
1913 }
1914 }
1915 /*
1916 * Figure out how many blocks we should have in the freelist.
1917 */
1918 agf = XFS_BUF_TO_AGF(agbp);
1919 need = XFS_MIN_FREELIST(agf, mp);
1920 /*
1921 * If there isn't enough total or single-extent, reject it.
1922 */
1923 if (!(flags & XFS_ALLOC_FLAG_FREEING)) {
1924 delta = need > be32_to_cpu(agf->agf_flcount) ?
1925 (need - be32_to_cpu(agf->agf_flcount)) : 0;
1926 longest = be32_to_cpu(agf->agf_longest);
1927 longest = (longest > delta) ? (longest - delta) :
1928 (be32_to_cpu(agf->agf_flcount) > 0 || longest > 0);
1929 if ((args->minlen + args->alignment + args->minalignslop - 1) >
1930 longest ||
1931 ((int)(be32_to_cpu(agf->agf_freeblks) +
1932 be32_to_cpu(agf->agf_flcount) - need - args->total) <
1933 (int)args->minleft)) {
1934 xfs_trans_brelse(tp, agbp);
1935 args->agbp = NULL;
1936 return 0;
1937 }
1938 }
1939 /*
1940 * Make the freelist shorter if it's too long.
1941 */
1942 while (be32_to_cpu(agf->agf_flcount) > need) {
1943 xfs_buf_t *bp;
1944
1945 error = xfs_alloc_get_freelist(tp, agbp, &bno, 0);
1946 if (error)
1947 return error;
1948 if ((error = xfs_free_ag_extent(tp, agbp, args->agno, bno, 1, 1)))
1949 return error;
1950 bp = xfs_btree_get_bufs(mp, tp, args->agno, bno, 0);
1951 xfs_trans_binval(tp, bp);
1952 }
1953 /*
1954 * Initialize the args structure.
1955 */
1956 memset(&targs, 0, sizeof(targs));
1957 targs.tp = tp;
1958 targs.mp = mp;
1959 targs.agbp = agbp;
1960 targs.agno = args->agno;
1961 targs.alignment = targs.minlen = targs.prod = targs.isfl = 1;
1962 targs.type = XFS_ALLOCTYPE_THIS_AG;
1963 targs.pag = pag;
1964 if ((error = xfs_alloc_read_agfl(mp, tp, targs.agno, &agflbp)))
1965 return error;
1966 /*
1967 * Make the freelist longer if it's too short.
1968 */
1969 while (be32_to_cpu(agf->agf_flcount) < need) {
1970 targs.agbno = 0;
1971 targs.maxlen = need - be32_to_cpu(agf->agf_flcount);
1972 /*
1973 * Allocate as many blocks as possible at once.
1974 */
1975 if ((error = xfs_alloc_ag_vextent(&targs))) {
1976 xfs_trans_brelse(tp, agflbp);
1977 return error;
1978 }
1979 /*
1980 * Stop if we run out. Won't happen if callers are obeying
1981 * the restrictions correctly. Can happen for free calls
1982 * on a completely full ag.
1983 */
1984 if (targs.agbno == NULLAGBLOCK) {
1985 if (flags & XFS_ALLOC_FLAG_FREEING)
1986 break;
1987 xfs_trans_brelse(tp, agflbp);
1988 args->agbp = NULL;
1989 return 0;
1990 }
1991 /*
1992 * Put each allocated block on the list.
1993 */
1994 for (bno = targs.agbno; bno < targs.agbno + targs.len; bno++) {
1995 error = xfs_alloc_put_freelist(tp, agbp,
1996 agflbp, bno, 0);
1997 if (error)
1998 return error;
1999 }
2000 }
2001 xfs_trans_brelse(tp, agflbp);
2002 args->agbp = agbp;
2003 return 0;
2004 }
2005
2006 /*
2007 * Get a block from the freelist.
2008 * Returns with the buffer for the block gotten.
2009 */
2010 int /* error */
2011 xfs_alloc_get_freelist(
2012 xfs_trans_t *tp, /* transaction pointer */
2013 xfs_buf_t *agbp, /* buffer containing the agf structure */
2014 xfs_agblock_t *bnop, /* block address retrieved from freelist */
2015 int btreeblk) /* destination is a AGF btree */
2016 {
2017 xfs_agf_t *agf; /* a.g. freespace structure */
2018 xfs_buf_t *agflbp;/* buffer for a.g. freelist structure */
2019 xfs_agblock_t bno; /* block number returned */
2020 __be32 *agfl_bno;
2021 int error;
2022 int logflags;
2023 xfs_mount_t *mp = tp->t_mountp;
2024 xfs_perag_t *pag; /* per allocation group data */
2025
2026 /*
2027 * Freelist is empty, give up.
2028 */
2029 agf = XFS_BUF_TO_AGF(agbp);
2030 if (!agf->agf_flcount) {
2031 *bnop = NULLAGBLOCK;
2032 return 0;
2033 }
2034 /*
2035 * Read the array of free blocks.
2036 */
2037 error = xfs_alloc_read_agfl(mp, tp, be32_to_cpu(agf->agf_seqno),
2038 &agflbp);
2039 if (error)
2040 return error;
2041
2042
2043 /*
2044 * Get the block number and update the data structures.
2045 */
2046 agfl_bno = XFS_BUF_TO_AGFL_BNO(mp, agflbp);
2047 bno = be32_to_cpu(agfl_bno[be32_to_cpu(agf->agf_flfirst)]);
2048 be32_add_cpu(&agf->agf_flfirst, 1);
2049 xfs_trans_brelse(tp, agflbp);
2050 if (be32_to_cpu(agf->agf_flfirst) == XFS_AGFL_SIZE(mp))
2051 agf->agf_flfirst = 0;
2052
2053 pag = xfs_perag_get(mp, be32_to_cpu(agf->agf_seqno));
2054 be32_add_cpu(&agf->agf_flcount, -1);
2055 xfs_trans_agflist_delta(tp, -1);
2056 pag->pagf_flcount--;
2057 xfs_perag_put(pag);
2058
2059 logflags = XFS_AGF_FLFIRST | XFS_AGF_FLCOUNT;
2060 if (btreeblk) {
2061 be32_add_cpu(&agf->agf_btreeblks, 1);
2062 pag->pagf_btreeblks++;
2063 logflags |= XFS_AGF_BTREEBLKS;
2064 }
2065
2066 xfs_alloc_log_agf(tp, agbp, logflags);
2067 *bnop = bno;
2068
2069 return 0;
2070 }
2071
2072 /*
2073 * Log the given fields from the agf structure.
2074 */
2075 void
2076 xfs_alloc_log_agf(
2077 xfs_trans_t *tp, /* transaction pointer */
2078 xfs_buf_t *bp, /* buffer for a.g. freelist header */
2079 int fields) /* mask of fields to be logged (XFS_AGF_...) */
2080 {
2081 int first; /* first byte offset */
2082 int last; /* last byte offset */
2083 static const short offsets[] = {
2084 offsetof(xfs_agf_t, agf_magicnum),
2085 offsetof(xfs_agf_t, agf_versionnum),
2086 offsetof(xfs_agf_t, agf_seqno),
2087 offsetof(xfs_agf_t, agf_length),
2088 offsetof(xfs_agf_t, agf_roots[0]),
2089 offsetof(xfs_agf_t, agf_levels[0]),
2090 offsetof(xfs_agf_t, agf_flfirst),
2091 offsetof(xfs_agf_t, agf_fllast),
2092 offsetof(xfs_agf_t, agf_flcount),
2093 offsetof(xfs_agf_t, agf_freeblks),
2094 offsetof(xfs_agf_t, agf_longest),
2095 offsetof(xfs_agf_t, agf_btreeblks),
2096 offsetof(xfs_agf_t, agf_uuid),
2097 sizeof(xfs_agf_t)
2098 };
2099
2100 trace_xfs_agf(tp->t_mountp, XFS_BUF_TO_AGF(bp), fields, _RET_IP_);
2101
2102 xfs_trans_buf_set_type(tp, bp, XFS_BLFT_AGF_BUF);
2103
2104 xfs_btree_offsets(fields, offsets, XFS_AGF_NUM_BITS, &first, &last);
2105 xfs_trans_log_buf(tp, bp, (uint)first, (uint)last);
2106 }
2107
2108 /*
2109 * Interface for inode allocation to force the pag data to be initialized.
2110 */
2111 int /* error */
2112 xfs_alloc_pagf_init(
2113 xfs_mount_t *mp, /* file system mount structure */
2114 xfs_trans_t *tp, /* transaction pointer */
2115 xfs_agnumber_t agno, /* allocation group number */
2116 int flags) /* XFS_ALLOC_FLAGS_... */
2117 {
2118 xfs_buf_t *bp;
2119 int error;
2120
2121 if ((error = xfs_alloc_read_agf(mp, tp, agno, flags, &bp)))
2122 return error;
2123 if (bp)
2124 xfs_trans_brelse(tp, bp);
2125 return 0;
2126 }
2127
2128 /*
2129 * Put the block on the freelist for the allocation group.
2130 */
2131 int /* error */
2132 xfs_alloc_put_freelist(
2133 xfs_trans_t *tp, /* transaction pointer */
2134 xfs_buf_t *agbp, /* buffer for a.g. freelist header */
2135 xfs_buf_t *agflbp,/* buffer for a.g. free block array */
2136 xfs_agblock_t bno, /* block being freed */
2137 int btreeblk) /* block came from a AGF btree */
2138 {
2139 xfs_agf_t *agf; /* a.g. freespace structure */
2140 __be32 *blockp;/* pointer to array entry */
2141 int error;
2142 int logflags;
2143 xfs_mount_t *mp; /* mount structure */
2144 xfs_perag_t *pag; /* per allocation group data */
2145 __be32 *agfl_bno;
2146 int startoff;
2147
2148 agf = XFS_BUF_TO_AGF(agbp);
2149 mp = tp->t_mountp;
2150
2151 if (!agflbp && (error = xfs_alloc_read_agfl(mp, tp,
2152 be32_to_cpu(agf->agf_seqno), &agflbp)))
2153 return error;
2154 be32_add_cpu(&agf->agf_fllast, 1);
2155 if (be32_to_cpu(agf->agf_fllast) == XFS_AGFL_SIZE(mp))
2156 agf->agf_fllast = 0;
2157
2158 pag = xfs_perag_get(mp, be32_to_cpu(agf->agf_seqno));
2159 be32_add_cpu(&agf->agf_flcount, 1);
2160 xfs_trans_agflist_delta(tp, 1);
2161 pag->pagf_flcount++;
2162
2163 logflags = XFS_AGF_FLLAST | XFS_AGF_FLCOUNT;
2164 if (btreeblk) {
2165 be32_add_cpu(&agf->agf_btreeblks, -1);
2166 pag->pagf_btreeblks--;
2167 logflags |= XFS_AGF_BTREEBLKS;
2168 }
2169 xfs_perag_put(pag);
2170
2171 xfs_alloc_log_agf(tp, agbp, logflags);
2172
2173 ASSERT(be32_to_cpu(agf->agf_flcount) <= XFS_AGFL_SIZE(mp));
2174
2175 agfl_bno = XFS_BUF_TO_AGFL_BNO(mp, agflbp);
2176 blockp = &agfl_bno[be32_to_cpu(agf->agf_fllast)];
2177 *blockp = cpu_to_be32(bno);
2178 startoff = (char *)blockp - (char *)agflbp->b_addr;
2179
2180 xfs_alloc_log_agf(tp, agbp, logflags);
2181
2182 xfs_trans_buf_set_type(tp, agflbp, XFS_BLFT_AGFL_BUF);
2183 xfs_trans_log_buf(tp, agflbp, startoff,
2184 startoff + sizeof(xfs_agblock_t) - 1);
2185 return 0;
2186 }
2187
2188 static bool
2189 xfs_agf_verify(
2190 struct xfs_mount *mp,
2191 struct xfs_buf *bp)
2192 {
2193 struct xfs_agf *agf = XFS_BUF_TO_AGF(bp);
2194
2195 if (xfs_sb_version_hascrc(&mp->m_sb) &&
2196 !uuid_equal(&agf->agf_uuid, &mp->m_sb.sb_uuid))
2197 return false;
2198
2199 if (!(agf->agf_magicnum == cpu_to_be32(XFS_AGF_MAGIC) &&
2200 XFS_AGF_GOOD_VERSION(be32_to_cpu(agf->agf_versionnum)) &&
2201 be32_to_cpu(agf->agf_freeblks) <= be32_to_cpu(agf->agf_length) &&
2202 be32_to_cpu(agf->agf_flfirst) < XFS_AGFL_SIZE(mp) &&
2203 be32_to_cpu(agf->agf_fllast) < XFS_AGFL_SIZE(mp) &&
2204 be32_to_cpu(agf->agf_flcount) <= XFS_AGFL_SIZE(mp)))
2205 return false;
2206
2207 /*
2208 * during growfs operations, the perag is not fully initialised,
2209 * so we can't use it for any useful checking. growfs ensures we can't
2210 * use it by using uncached buffers that don't have the perag attached
2211 * so we can detect and avoid this problem.
2212 */
2213 if (bp->b_pag && be32_to_cpu(agf->agf_seqno) != bp->b_pag->pag_agno)
2214 return false;
2215
2216 if (xfs_sb_version_haslazysbcount(&mp->m_sb) &&
2217 be32_to_cpu(agf->agf_btreeblks) > be32_to_cpu(agf->agf_length))
2218 return false;
2219
2220 return true;;
2221
2222 }
2223
2224 static void
2225 xfs_agf_read_verify(
2226 struct xfs_buf *bp)
2227 {
2228 struct xfs_mount *mp = bp->b_target->bt_mount;
2229 int agf_ok = 1;
2230
2231 if (xfs_sb_version_hascrc(&mp->m_sb))
2232 agf_ok = xfs_verify_cksum(bp->b_addr, BBTOB(bp->b_length),
2233 offsetof(struct xfs_agf, agf_crc));
2234
2235 agf_ok = agf_ok && xfs_agf_verify(mp, bp);
2236
2237 if (unlikely(XFS_TEST_ERROR(!agf_ok, mp, XFS_ERRTAG_ALLOC_READ_AGF,
2238 XFS_RANDOM_ALLOC_READ_AGF))) {
2239 XFS_CORRUPTION_ERROR(__func__, XFS_ERRLEVEL_LOW, mp, bp->b_addr);
2240 xfs_buf_ioerror(bp, EFSCORRUPTED);
2241 }
2242 }
2243
2244 static void
2245 xfs_agf_write_verify(
2246 struct xfs_buf *bp)
2247 {
2248 struct xfs_mount *mp = bp->b_target->bt_mount;
2249 struct xfs_buf_log_item *bip = bp->b_fspriv;
2250
2251 if (!xfs_agf_verify(mp, bp)) {
2252 XFS_CORRUPTION_ERROR(__func__, XFS_ERRLEVEL_LOW, mp, bp->b_addr);
2253 xfs_buf_ioerror(bp, EFSCORRUPTED);
2254 return;
2255 }
2256
2257 if (!xfs_sb_version_hascrc(&mp->m_sb))
2258 return;
2259
2260 if (bip)
2261 XFS_BUF_TO_AGF(bp)->agf_lsn = cpu_to_be64(bip->bli_item.li_lsn);
2262
2263 xfs_update_cksum(bp->b_addr, BBTOB(bp->b_length),
2264 offsetof(struct xfs_agf, agf_crc));
2265 }
2266
2267 const struct xfs_buf_ops xfs_agf_buf_ops = {
2268 .verify_read = xfs_agf_read_verify,
2269 .verify_write = xfs_agf_write_verify,
2270 };
2271
2272 /*
2273 * Read in the allocation group header (free/alloc section).
2274 */
2275 int /* error */
2276 xfs_read_agf(
2277 struct xfs_mount *mp, /* mount point structure */
2278 struct xfs_trans *tp, /* transaction pointer */
2279 xfs_agnumber_t agno, /* allocation group number */
2280 int flags, /* XFS_BUF_ */
2281 struct xfs_buf **bpp) /* buffer for the ag freelist header */
2282 {
2283 int error;
2284
2285 ASSERT(agno != NULLAGNUMBER);
2286 error = xfs_trans_read_buf(
2287 mp, tp, mp->m_ddev_targp,
2288 XFS_AG_DADDR(mp, agno, XFS_AGF_DADDR(mp)),
2289 XFS_FSS_TO_BB(mp, 1), flags, bpp, &xfs_agf_buf_ops);
2290 if (error)
2291 return error;
2292 if (!*bpp)
2293 return 0;
2294
2295 ASSERT(!(*bpp)->b_error);
2296 xfs_buf_set_ref(*bpp, XFS_AGF_REF);
2297 return 0;
2298 }
2299
2300 /*
2301 * Read in the allocation group header (free/alloc section).
2302 */
2303 int /* error */
2304 xfs_alloc_read_agf(
2305 struct xfs_mount *mp, /* mount point structure */
2306 struct xfs_trans *tp, /* transaction pointer */
2307 xfs_agnumber_t agno, /* allocation group number */
2308 int flags, /* XFS_ALLOC_FLAG_... */
2309 struct xfs_buf **bpp) /* buffer for the ag freelist header */
2310 {
2311 struct xfs_agf *agf; /* ag freelist header */
2312 struct xfs_perag *pag; /* per allocation group data */
2313 int error;
2314
2315 ASSERT(agno != NULLAGNUMBER);
2316
2317 error = xfs_read_agf(mp, tp, agno,
2318 (flags & XFS_ALLOC_FLAG_TRYLOCK) ? XBF_TRYLOCK : 0,
2319 bpp);
2320 if (error)
2321 return error;
2322 if (!*bpp)
2323 return 0;
2324 ASSERT(!(*bpp)->b_error);
2325
2326 agf = XFS_BUF_TO_AGF(*bpp);
2327 pag = xfs_perag_get(mp, agno);
2328 if (!pag->pagf_init) {
2329 pag->pagf_freeblks = be32_to_cpu(agf->agf_freeblks);
2330 pag->pagf_btreeblks = be32_to_cpu(agf->agf_btreeblks);
2331 pag->pagf_flcount = be32_to_cpu(agf->agf_flcount);
2332 pag->pagf_longest = be32_to_cpu(agf->agf_longest);
2333 pag->pagf_levels[XFS_BTNUM_BNOi] =
2334 be32_to_cpu(agf->agf_levels[XFS_BTNUM_BNOi]);
2335 pag->pagf_levels[XFS_BTNUM_CNTi] =
2336 be32_to_cpu(agf->agf_levels[XFS_BTNUM_CNTi]);
2337 spin_lock_init(&pag->pagb_lock);
2338 pag->pagb_count = 0;
2339 pag->pagb_tree = RB_ROOT;
2340 pag->pagf_init = 1;
2341 }
2342 #ifdef DEBUG
2343 else if (!XFS_FORCED_SHUTDOWN(mp)) {
2344 ASSERT(pag->pagf_freeblks == be32_to_cpu(agf->agf_freeblks));
2345 ASSERT(pag->pagf_btreeblks == be32_to_cpu(agf->agf_btreeblks));
2346 ASSERT(pag->pagf_flcount == be32_to_cpu(agf->agf_flcount));
2347 ASSERT(pag->pagf_longest == be32_to_cpu(agf->agf_longest));
2348 ASSERT(pag->pagf_levels[XFS_BTNUM_BNOi] ==
2349 be32_to_cpu(agf->agf_levels[XFS_BTNUM_BNOi]));
2350 ASSERT(pag->pagf_levels[XFS_BTNUM_CNTi] ==
2351 be32_to_cpu(agf->agf_levels[XFS_BTNUM_CNTi]));
2352 }
2353 #endif
2354 xfs_perag_put(pag);
2355 return 0;
2356 }
2357
2358 /*
2359 * Allocate an extent (variable-size).
2360 * Depending on the allocation type, we either look in a single allocation
2361 * group or loop over the allocation groups to find the result.
2362 */
2363 int /* error */
2364 xfs_alloc_vextent(
2365 xfs_alloc_arg_t *args) /* allocation argument structure */
2366 {
2367 xfs_agblock_t agsize; /* allocation group size */
2368 int error;
2369 int flags; /* XFS_ALLOC_FLAG_... locking flags */
2370 xfs_extlen_t minleft;/* minimum left value, temp copy */
2371 xfs_mount_t *mp; /* mount structure pointer */
2372 xfs_agnumber_t sagno; /* starting allocation group number */
2373 xfs_alloctype_t type; /* input allocation type */
2374 int bump_rotor = 0;
2375 int no_min = 0;
2376 xfs_agnumber_t rotorstep = xfs_rotorstep; /* inode32 agf stepper */
2377
2378 mp = args->mp;
2379 type = args->otype = args->type;
2380 args->agbno = NULLAGBLOCK;
2381 /*
2382 * Just fix this up, for the case where the last a.g. is shorter
2383 * (or there's only one a.g.) and the caller couldn't easily figure
2384 * that out (xfs_bmap_alloc).
2385 */
2386 agsize = mp->m_sb.sb_agblocks;
2387 if (args->maxlen > agsize)
2388 args->maxlen = agsize;
2389 if (args->alignment == 0)
2390 args->alignment = 1;
2391 ASSERT(XFS_FSB_TO_AGNO(mp, args->fsbno) < mp->m_sb.sb_agcount);
2392 ASSERT(XFS_FSB_TO_AGBNO(mp, args->fsbno) < agsize);
2393 ASSERT(args->minlen <= args->maxlen);
2394 ASSERT(args->minlen <= agsize);
2395 ASSERT(args->mod < args->prod);
2396 if (XFS_FSB_TO_AGNO(mp, args->fsbno) >= mp->m_sb.sb_agcount ||
2397 XFS_FSB_TO_AGBNO(mp, args->fsbno) >= agsize ||
2398 args->minlen > args->maxlen || args->minlen > agsize ||
2399 args->mod >= args->prod) {
2400 args->fsbno = NULLFSBLOCK;
2401 trace_xfs_alloc_vextent_badargs(args);
2402 return 0;
2403 }
2404 minleft = args->minleft;
2405
2406 switch (type) {
2407 case XFS_ALLOCTYPE_THIS_AG:
2408 case XFS_ALLOCTYPE_NEAR_BNO:
2409 case XFS_ALLOCTYPE_THIS_BNO:
2410 /*
2411 * These three force us into a single a.g.
2412 */
2413 args->agno = XFS_FSB_TO_AGNO(mp, args->fsbno);
2414 args->pag = xfs_perag_get(mp, args->agno);
2415 args->minleft = 0;
2416 error = xfs_alloc_fix_freelist(args, 0);
2417 args->minleft = minleft;
2418 if (error) {
2419 trace_xfs_alloc_vextent_nofix(args);
2420 goto error0;
2421 }
2422 if (!args->agbp) {
2423 trace_xfs_alloc_vextent_noagbp(args);
2424 break;
2425 }
2426 args->agbno = XFS_FSB_TO_AGBNO(mp, args->fsbno);
2427 if ((error = xfs_alloc_ag_vextent(args)))
2428 goto error0;
2429 break;
2430 case XFS_ALLOCTYPE_START_BNO:
2431 /*
2432 * Try near allocation first, then anywhere-in-ag after
2433 * the first a.g. fails.
2434 */
2435 if ((args->userdata == XFS_ALLOC_INITIAL_USER_DATA) &&
2436 (mp->m_flags & XFS_MOUNT_32BITINODES)) {
2437 args->fsbno = XFS_AGB_TO_FSB(mp,
2438 ((mp->m_agfrotor / rotorstep) %
2439 mp->m_sb.sb_agcount), 0);
2440 bump_rotor = 1;
2441 }
2442 args->agbno = XFS_FSB_TO_AGBNO(mp, args->fsbno);
2443 args->type = XFS_ALLOCTYPE_NEAR_BNO;
2444 /* FALLTHROUGH */
2445 case XFS_ALLOCTYPE_ANY_AG:
2446 case XFS_ALLOCTYPE_START_AG:
2447 case XFS_ALLOCTYPE_FIRST_AG:
2448 /*
2449 * Rotate through the allocation groups looking for a winner.
2450 */
2451 if (type == XFS_ALLOCTYPE_ANY_AG) {
2452 /*
2453 * Start with the last place we left off.
2454 */
2455 args->agno = sagno = (mp->m_agfrotor / rotorstep) %
2456 mp->m_sb.sb_agcount;
2457 args->type = XFS_ALLOCTYPE_THIS_AG;
2458 flags = XFS_ALLOC_FLAG_TRYLOCK;
2459 } else if (type == XFS_ALLOCTYPE_FIRST_AG) {
2460 /*
2461 * Start with allocation group given by bno.
2462 */
2463 args->agno = XFS_FSB_TO_AGNO(mp, args->fsbno);
2464 args->type = XFS_ALLOCTYPE_THIS_AG;
2465 sagno = 0;
2466 flags = 0;
2467 } else {
2468 if (type == XFS_ALLOCTYPE_START_AG)
2469 args->type = XFS_ALLOCTYPE_THIS_AG;
2470 /*
2471 * Start with the given allocation group.
2472 */
2473 args->agno = sagno = XFS_FSB_TO_AGNO(mp, args->fsbno);
2474 flags = XFS_ALLOC_FLAG_TRYLOCK;
2475 }
2476 /*
2477 * Loop over allocation groups twice; first time with
2478 * trylock set, second time without.
2479 */
2480 for (;;) {
2481 args->pag = xfs_perag_get(mp, args->agno);
2482 if (no_min) args->minleft = 0;
2483 error = xfs_alloc_fix_freelist(args, flags);
2484 args->minleft = minleft;
2485 if (error) {
2486 trace_xfs_alloc_vextent_nofix(args);
2487 goto error0;
2488 }
2489 /*
2490 * If we get a buffer back then the allocation will fly.
2491 */
2492 if (args->agbp) {
2493 if ((error = xfs_alloc_ag_vextent(args)))
2494 goto error0;
2495 break;
2496 }
2497
2498 trace_xfs_alloc_vextent_loopfailed(args);
2499
2500 /*
2501 * Didn't work, figure out the next iteration.
2502 */
2503 if (args->agno == sagno &&
2504 type == XFS_ALLOCTYPE_START_BNO)
2505 args->type = XFS_ALLOCTYPE_THIS_AG;
2506 /*
2507 * For the first allocation, we can try any AG to get
2508 * space. However, if we already have allocated a
2509 * block, we don't want to try AGs whose number is below
2510 * sagno. Otherwise, we may end up with out-of-order
2511 * locking of AGF, which might cause deadlock.
2512 */
2513 if (++(args->agno) == mp->m_sb.sb_agcount) {
2514 if (args->firstblock != NULLFSBLOCK)
2515 args->agno = sagno;
2516 else
2517 args->agno = 0;
2518 }
2519 /*
2520 * Reached the starting a.g., must either be done
2521 * or switch to non-trylock mode.
2522 */
2523 if (args->agno == sagno) {
2524 if (no_min == 1) {
2525 args->agbno = NULLAGBLOCK;
2526 trace_xfs_alloc_vextent_allfailed(args);
2527 break;
2528 }
2529 if (flags == 0) {
2530 no_min = 1;
2531 } else {
2532 flags = 0;
2533 if (type == XFS_ALLOCTYPE_START_BNO) {
2534 args->agbno = XFS_FSB_TO_AGBNO(mp,
2535 args->fsbno);
2536 args->type = XFS_ALLOCTYPE_NEAR_BNO;
2537 }
2538 }
2539 }
2540 xfs_perag_put(args->pag);
2541 }
2542 if (bump_rotor || (type == XFS_ALLOCTYPE_ANY_AG)) {
2543 if (args->agno == sagno)
2544 mp->m_agfrotor = (mp->m_agfrotor + 1) %
2545 (mp->m_sb.sb_agcount * rotorstep);
2546 else
2547 mp->m_agfrotor = (args->agno * rotorstep + 1) %
2548 (mp->m_sb.sb_agcount * rotorstep);
2549 }
2550 break;
2551 default:
2552 ASSERT(0);
2553 /* NOTREACHED */
2554 }
2555 if (args->agbno == NULLAGBLOCK)
2556 args->fsbno = NULLFSBLOCK;
2557 else {
2558 args->fsbno = XFS_AGB_TO_FSB(mp, args->agno, args->agbno);
2559 #ifdef DEBUG
2560 ASSERT(args->len >= args->minlen);
2561 ASSERT(args->len <= args->maxlen);
2562 ASSERT(args->agbno % args->alignment == 0);
2563 XFS_AG_CHECK_DADDR(mp, XFS_FSB_TO_DADDR(mp, args->fsbno),
2564 args->len);
2565 #endif
2566 }
2567 xfs_perag_put(args->pag);
2568 return 0;
2569 error0:
2570 xfs_perag_put(args->pag);
2571 return error;
2572 }
2573
2574 /*
2575 * Free an extent.
2576 * Just break up the extent address and hand off to xfs_free_ag_extent
2577 * after fixing up the freelist.
2578 */
2579 int /* error */
2580 xfs_free_extent(
2581 xfs_trans_t *tp, /* transaction pointer */
2582 xfs_fsblock_t bno, /* starting block number of extent */
2583 xfs_extlen_t len) /* length of extent */
2584 {
2585 xfs_alloc_arg_t args;
2586 int error;
2587
2588 ASSERT(len != 0);
2589 memset(&args, 0, sizeof(xfs_alloc_arg_t));
2590 args.tp = tp;
2591 args.mp = tp->t_mountp;
2592
2593 /*
2594 * validate that the block number is legal - the enables us to detect
2595 * and handle a silent filesystem corruption rather than crashing.
2596 */
2597 args.agno = XFS_FSB_TO_AGNO(args.mp, bno);
2598 if (args.agno >= args.mp->m_sb.sb_agcount)
2599 return EFSCORRUPTED;
2600
2601 args.agbno = XFS_FSB_TO_AGBNO(args.mp, bno);
2602 if (args.agbno >= args.mp->m_sb.sb_agblocks)
2603 return EFSCORRUPTED;
2604
2605 args.pag = xfs_perag_get(args.mp, args.agno);
2606 ASSERT(args.pag);
2607
2608 error = xfs_alloc_fix_freelist(&args, XFS_ALLOC_FLAG_FREEING);
2609 if (error)
2610 goto error0;
2611
2612 /* validate the extent size is legal now we have the agf locked */
2613 if (args.agbno + len >
2614 be32_to_cpu(XFS_BUF_TO_AGF(args.agbp)->agf_length)) {
2615 error = EFSCORRUPTED;
2616 goto error0;
2617 }
2618
2619 error = xfs_free_ag_extent(tp, args.agbp, args.agno, args.agbno, len, 0);
2620 if (!error)
2621 xfs_extent_busy_insert(tp, args.agno, args.agbno, len, 0);
2622 error0:
2623 xfs_perag_put(args.pag);
2624 return error;
2625 }
Linus' kernel tree