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1/*
2 * Copyright (c) 2000-2002,2005 Silicon Graphics, Inc.
3 * All Rights Reserved.
4 *
5 * This program is free software; you can redistribute it and/or
6 * modify it under the terms of the GNU General Public License as
7 * published by the Free Software Foundation.
8 *
9 * This program is distributed in the hope that it would be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
13 *
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, write the Free Software Foundation,
16 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
17 */
18#include "xfs.h"
19#include "xfs_fs.h"
20#include "xfs_types.h"
21#include "xfs_bit.h"
22#include "xfs_log.h"
23#include "xfs_inum.h"
24#include "xfs_trans.h"
25#include "xfs_sb.h"
26#include "xfs_ag.h"
27#include "xfs_mount.h"
28#include "xfs_bmap_btree.h"
29#include "xfs_alloc_btree.h"
30#include "xfs_ialloc_btree.h"
31#include "xfs_dinode.h"
32#include "xfs_inode.h"
33#include "xfs_btree.h"
34#include "xfs_alloc.h"
35#include "xfs_error.h"
36#include "xfs_trace.h"
37
38
39#define XFS_ABSDIFF(a,b) (((a) <= (b)) ? ((b) - (a)) : ((a) - (b)))
40
41#define XFSA_FIXUP_BNO_OK 1
42#define XFSA_FIXUP_CNT_OK 2
43
44STATIC int xfs_alloc_ag_vextent_exact(xfs_alloc_arg_t *);
45STATIC int xfs_alloc_ag_vextent_near(xfs_alloc_arg_t *);
46STATIC int xfs_alloc_ag_vextent_size(xfs_alloc_arg_t *);
47STATIC int xfs_alloc_ag_vextent_small(xfs_alloc_arg_t *,
48 xfs_btree_cur_t *, xfs_agblock_t *, xfs_extlen_t *, int *);
49STATIC void xfs_alloc_busy_trim(struct xfs_alloc_arg *,
50 xfs_agblock_t, xfs_extlen_t, xfs_agblock_t *, xfs_extlen_t *);
51
52/*
53 * Lookup the record equal to [bno, len] in the btree given by cur.
54 */
55STATIC int /* error */
56xfs_alloc_lookup_eq(
57 struct xfs_btree_cur *cur, /* btree cursor */
58 xfs_agblock_t bno, /* starting block of extent */
59 xfs_extlen_t len, /* length of extent */
60 int *stat) /* success/failure */
61{
62 cur->bc_rec.a.ar_startblock = bno;
63 cur->bc_rec.a.ar_blockcount = len;
64 return xfs_btree_lookup(cur, XFS_LOOKUP_EQ, stat);
65}
66
67/*
68 * Lookup the first record greater than or equal to [bno, len]
69 * in the btree given by cur.
70 */
71STATIC int /* error */
72xfs_alloc_lookup_ge(
73 struct xfs_btree_cur *cur, /* btree cursor */
74 xfs_agblock_t bno, /* starting block of extent */
75 xfs_extlen_t len, /* length of extent */
76 int *stat) /* success/failure */
77{
78 cur->bc_rec.a.ar_startblock = bno;
79 cur->bc_rec.a.ar_blockcount = len;
80 return xfs_btree_lookup(cur, XFS_LOOKUP_GE, stat);
81}
82
83/*
84 * Lookup the first record less than or equal to [bno, len]
85 * in the btree given by cur.
86 */
87int /* error */
88xfs_alloc_lookup_le(
89 struct xfs_btree_cur *cur, /* btree cursor */
90 xfs_agblock_t bno, /* starting block of extent */
91 xfs_extlen_t len, /* length of extent */
92 int *stat) /* success/failure */
93{
94 cur->bc_rec.a.ar_startblock = bno;
95 cur->bc_rec.a.ar_blockcount = len;
96 return xfs_btree_lookup(cur, XFS_LOOKUP_LE, stat);
97}
98
99/*
100 * Update the record referred to by cur to the value given
101 * by [bno, len].
102 * This either works (return 0) or gets an EFSCORRUPTED error.
103 */
104STATIC int /* error */
105xfs_alloc_update(
106 struct xfs_btree_cur *cur, /* btree cursor */
107 xfs_agblock_t bno, /* starting block of extent */
108 xfs_extlen_t len) /* length of extent */
109{
110 union xfs_btree_rec rec;
111
112 rec.alloc.ar_startblock = cpu_to_be32(bno);
113 rec.alloc.ar_blockcount = cpu_to_be32(len);
114 return xfs_btree_update(cur, &rec);
115}
116
117/*
118 * Get the data from the pointed-to record.
119 */
120int /* error */
121xfs_alloc_get_rec(
122 struct xfs_btree_cur *cur, /* btree cursor */
123 xfs_agblock_t *bno, /* output: starting block of extent */
124 xfs_extlen_t *len, /* output: length of extent */
125 int *stat) /* output: success/failure */
126{
127 union xfs_btree_rec *rec;
128 int error;
129
130 error = xfs_btree_get_rec(cur, &rec, stat);
131 if (!error && *stat == 1) {
132 *bno = be32_to_cpu(rec->alloc.ar_startblock);
133 *len = be32_to_cpu(rec->alloc.ar_blockcount);
134 }
135 return error;
136}
137
138/*
139 * Compute aligned version of the found extent.
140 * Takes alignment and min length into account.
141 */
142STATIC void
143xfs_alloc_compute_aligned(
144 xfs_alloc_arg_t *args, /* allocation argument structure */
145 xfs_agblock_t foundbno, /* starting block in found extent */
146 xfs_extlen_t foundlen, /* length in found extent */
147 xfs_agblock_t *resbno, /* result block number */
148 xfs_extlen_t *reslen) /* result length */
149{
150 xfs_agblock_t bno;
151 xfs_extlen_t len;
152
153 /* Trim busy sections out of found extent */
154 xfs_alloc_busy_trim(args, foundbno, foundlen, &bno, &len);
155
156 if (args->alignment > 1 && len >= args->minlen) {
157 xfs_agblock_t aligned_bno = roundup(bno, args->alignment);
158 xfs_extlen_t diff = aligned_bno - bno;
159
160 *resbno = aligned_bno;
161 *reslen = diff >= len ? 0 : len - diff;
162 } else {
163 *resbno = bno;
164 *reslen = len;
165 }
166}
167
168/*
169 * Compute best start block and diff for "near" allocations.
170 * freelen >= wantlen already checked by caller.
171 */
172STATIC xfs_extlen_t /* difference value (absolute) */
173xfs_alloc_compute_diff(
174 xfs_agblock_t wantbno, /* target starting block */
175 xfs_extlen_t wantlen, /* target length */
176 xfs_extlen_t alignment, /* target alignment */
177 xfs_agblock_t freebno, /* freespace's starting block */
178 xfs_extlen_t freelen, /* freespace's length */
179 xfs_agblock_t *newbnop) /* result: best start block from free */
180{
181 xfs_agblock_t freeend; /* end of freespace extent */
182 xfs_agblock_t newbno1; /* return block number */
183 xfs_agblock_t newbno2; /* other new block number */
184 xfs_extlen_t newlen1=0; /* length with newbno1 */
185 xfs_extlen_t newlen2=0; /* length with newbno2 */
186 xfs_agblock_t wantend; /* end of target extent */
187
188 ASSERT(freelen >= wantlen);
189 freeend = freebno + freelen;
190 wantend = wantbno + wantlen;
191 if (freebno >= wantbno) {
192 if ((newbno1 = roundup(freebno, alignment)) >= freeend)
193 newbno1 = NULLAGBLOCK;
194 } else if (freeend >= wantend && alignment > 1) {
195 newbno1 = roundup(wantbno, alignment);
196 newbno2 = newbno1 - alignment;
197 if (newbno1 >= freeend)
198 newbno1 = NULLAGBLOCK;
199 else
200 newlen1 = XFS_EXTLEN_MIN(wantlen, freeend - newbno1);
201 if (newbno2 < freebno)
202 newbno2 = NULLAGBLOCK;
203 else
204 newlen2 = XFS_EXTLEN_MIN(wantlen, freeend - newbno2);
205 if (newbno1 != NULLAGBLOCK && newbno2 != NULLAGBLOCK) {
206 if (newlen1 < newlen2 ||
207 (newlen1 == newlen2 &&
208 XFS_ABSDIFF(newbno1, wantbno) >
209 XFS_ABSDIFF(newbno2, wantbno)))
210 newbno1 = newbno2;
211 } else if (newbno2 != NULLAGBLOCK)
212 newbno1 = newbno2;
213 } else if (freeend >= wantend) {
214 newbno1 = wantbno;
215 } else if (alignment > 1) {
216 newbno1 = roundup(freeend - wantlen, alignment);
217 if (newbno1 > freeend - wantlen &&
218 newbno1 - alignment >= freebno)
219 newbno1 -= alignment;
220 else if (newbno1 >= freeend)
221 newbno1 = NULLAGBLOCK;
222 } else
223 newbno1 = freeend - wantlen;
224 *newbnop = newbno1;
225 return newbno1 == NULLAGBLOCK ? 0 : XFS_ABSDIFF(newbno1, wantbno);
226}
227
228/*
229 * Fix up the length, based on mod and prod.
230 * len should be k * prod + mod for some k.
231 * If len is too small it is returned unchanged.
232 * If len hits maxlen it is left alone.
233 */
234STATIC void
235xfs_alloc_fix_len(
236 xfs_alloc_arg_t *args) /* allocation argument structure */
237{
238 xfs_extlen_t k;
239 xfs_extlen_t rlen;
240
241 ASSERT(args->mod < args->prod);
242 rlen = args->len;
243 ASSERT(rlen >= args->minlen);
244 ASSERT(rlen <= args->maxlen);
245 if (args->prod <= 1 || rlen < args->mod || rlen == args->maxlen ||
246 (args->mod == 0 && rlen < args->prod))
247 return;
248 k = rlen % args->prod;
249 if (k == args->mod)
250 return;
251 if (k > args->mod) {
252 if ((int)(rlen = rlen - k - args->mod) < (int)args->minlen)
253 return;
254 } else {
255 if ((int)(rlen = rlen - args->prod - (args->mod - k)) <
256 (int)args->minlen)
257 return;
258 }
259 ASSERT(rlen >= args->minlen);
260 ASSERT(rlen <= args->maxlen);
261 args->len = rlen;
262}
263
264/*
265 * Fix up length if there is too little space left in the a.g.
266 * Return 1 if ok, 0 if too little, should give up.
267 */
268STATIC int
269xfs_alloc_fix_minleft(
270 xfs_alloc_arg_t *args) /* allocation argument structure */
271{
272 xfs_agf_t *agf; /* a.g. freelist header */
273 int diff; /* free space difference */
274
275 if (args->minleft == 0)
276 return 1;
277 agf = XFS_BUF_TO_AGF(args->agbp);
278 diff = be32_to_cpu(agf->agf_freeblks)
279 - args->len - args->minleft;
280 if (diff >= 0)
281 return 1;
282 args->len += diff; /* shrink the allocated space */
283 if (args->len >= args->minlen)
284 return 1;
285 args->agbno = NULLAGBLOCK;
286 return 0;
287}
288
289/*
290 * Update the two btrees, logically removing from freespace the extent
291 * starting at rbno, rlen blocks. The extent is contained within the
292 * actual (current) free extent fbno for flen blocks.
293 * Flags are passed in indicating whether the cursors are set to the
294 * relevant records.
295 */
296STATIC int /* error code */
297xfs_alloc_fixup_trees(
298 xfs_btree_cur_t *cnt_cur, /* cursor for by-size btree */
299 xfs_btree_cur_t *bno_cur, /* cursor for by-block btree */
300 xfs_agblock_t fbno, /* starting block of free extent */
301 xfs_extlen_t flen, /* length of free extent */
302 xfs_agblock_t rbno, /* starting block of returned extent */
303 xfs_extlen_t rlen, /* length of returned extent */
304 int flags) /* flags, XFSA_FIXUP_... */
305{
306 int error; /* error code */
307 int i; /* operation results */
308 xfs_agblock_t nfbno1; /* first new free startblock */
309 xfs_agblock_t nfbno2; /* second new free startblock */
310 xfs_extlen_t nflen1=0; /* first new free length */
311 xfs_extlen_t nflen2=0; /* second new free length */
312
313 /*
314 * Look up the record in the by-size tree if necessary.
315 */
316 if (flags & XFSA_FIXUP_CNT_OK) {
317#ifdef DEBUG
318 if ((error = xfs_alloc_get_rec(cnt_cur, &nfbno1, &nflen1, &i)))
319 return error;
320 XFS_WANT_CORRUPTED_RETURN(
321 i == 1 && nfbno1 == fbno && nflen1 == flen);
322#endif
323 } else {
324 if ((error = xfs_alloc_lookup_eq(cnt_cur, fbno, flen, &i)))
325 return error;
326 XFS_WANT_CORRUPTED_RETURN(i == 1);
327 }
328 /*
329 * Look up the record in the by-block tree if necessary.
330 */
331 if (flags & XFSA_FIXUP_BNO_OK) {
332#ifdef DEBUG
333 if ((error = xfs_alloc_get_rec(bno_cur, &nfbno1, &nflen1, &i)))
334 return error;
335 XFS_WANT_CORRUPTED_RETURN(
336 i == 1 && nfbno1 == fbno && nflen1 == flen);
337#endif
338 } else {
339 if ((error = xfs_alloc_lookup_eq(bno_cur, fbno, flen, &i)))
340 return error;
341 XFS_WANT_CORRUPTED_RETURN(i == 1);
342 }
343
344#ifdef DEBUG
345 if (bno_cur->bc_nlevels == 1 && cnt_cur->bc_nlevels == 1) {
346 struct xfs_btree_block *bnoblock;
347 struct xfs_btree_block *cntblock;
348
349 bnoblock = XFS_BUF_TO_BLOCK(bno_cur->bc_bufs[0]);
350 cntblock = XFS_BUF_TO_BLOCK(cnt_cur->bc_bufs[0]);
351
352 XFS_WANT_CORRUPTED_RETURN(
353 bnoblock->bb_numrecs == cntblock->bb_numrecs);
354 }
355#endif
356
357 /*
358 * Deal with all four cases: the allocated record is contained
359 * within the freespace record, so we can have new freespace
360 * at either (or both) end, or no freespace remaining.
361 */
362 if (rbno == fbno && rlen == flen)
363 nfbno1 = nfbno2 = NULLAGBLOCK;
364 else if (rbno == fbno) {
365 nfbno1 = rbno + rlen;
366 nflen1 = flen - rlen;
367 nfbno2 = NULLAGBLOCK;
368 } else if (rbno + rlen == fbno + flen) {
369 nfbno1 = fbno;
370 nflen1 = flen - rlen;
371 nfbno2 = NULLAGBLOCK;
372 } else {
373 nfbno1 = fbno;
374 nflen1 = rbno - fbno;
375 nfbno2 = rbno + rlen;
376 nflen2 = (fbno + flen) - nfbno2;
377 }
378 /*
379 * Delete the entry from the by-size btree.
380 */
381 if ((error = xfs_btree_delete(cnt_cur, &i)))
382 return error;
383 XFS_WANT_CORRUPTED_RETURN(i == 1);
384 /*
385 * Add new by-size btree entry(s).
386 */
387 if (nfbno1 != NULLAGBLOCK) {
388 if ((error = xfs_alloc_lookup_eq(cnt_cur, nfbno1, nflen1, &i)))
389 return error;
390 XFS_WANT_CORRUPTED_RETURN(i == 0);
391 if ((error = xfs_btree_insert(cnt_cur, &i)))
392 return error;
393 XFS_WANT_CORRUPTED_RETURN(i == 1);
394 }
395 if (nfbno2 != NULLAGBLOCK) {
396 if ((error = xfs_alloc_lookup_eq(cnt_cur, nfbno2, nflen2, &i)))
397 return error;
398 XFS_WANT_CORRUPTED_RETURN(i == 0);
399 if ((error = xfs_btree_insert(cnt_cur, &i)))
400 return error;
401 XFS_WANT_CORRUPTED_RETURN(i == 1);
402 }
403 /*
404 * Fix up the by-block btree entry(s).
405 */
406 if (nfbno1 == NULLAGBLOCK) {
407 /*
408 * No remaining freespace, just delete the by-block tree entry.
409 */
410 if ((error = xfs_btree_delete(bno_cur, &i)))
411 return error;
412 XFS_WANT_CORRUPTED_RETURN(i == 1);
413 } else {
414 /*
415 * Update the by-block entry to start later|be shorter.
416 */
417 if ((error = xfs_alloc_update(bno_cur, nfbno1, nflen1)))
418 return error;
419 }
420 if (nfbno2 != NULLAGBLOCK) {
421 /*
422 * 2 resulting free entries, need to add one.
423 */
424 if ((error = xfs_alloc_lookup_eq(bno_cur, nfbno2, nflen2, &i)))
425 return error;
426 XFS_WANT_CORRUPTED_RETURN(i == 0);
427 if ((error = xfs_btree_insert(bno_cur, &i)))
428 return error;
429 XFS_WANT_CORRUPTED_RETURN(i == 1);
430 }
431 return 0;
432}
433
434/*
435 * Read in the allocation group free block array.
436 */
437STATIC int /* error */
438xfs_alloc_read_agfl(
439 xfs_mount_t *mp, /* mount point structure */
440 xfs_trans_t *tp, /* transaction pointer */
441 xfs_agnumber_t agno, /* allocation group number */
442 xfs_buf_t **bpp) /* buffer for the ag free block array */
443{
444 xfs_buf_t *bp; /* return value */
445 int error;
446
447 ASSERT(agno != NULLAGNUMBER);
448 error = xfs_trans_read_buf(
449 mp, tp, mp->m_ddev_targp,
450 XFS_AG_DADDR(mp, agno, XFS_AGFL_DADDR(mp)),
451 XFS_FSS_TO_BB(mp, 1), 0, &bp);
452 if (error)
453 return error;
454 ASSERT(!xfs_buf_geterror(bp));
455 XFS_BUF_SET_VTYPE_REF(bp, B_FS_AGFL, XFS_AGFL_REF);
456 *bpp = bp;
457 return 0;
458}
459
460STATIC int
461xfs_alloc_update_counters(
462 struct xfs_trans *tp,
463 struct xfs_perag *pag,
464 struct xfs_buf *agbp,
465 long len)
466{
467 struct xfs_agf *agf = XFS_BUF_TO_AGF(agbp);
468
469 pag->pagf_freeblks += len;
470 be32_add_cpu(&agf->agf_freeblks, len);
471
472 xfs_trans_agblocks_delta(tp, len);
473 if (unlikely(be32_to_cpu(agf->agf_freeblks) >
474 be32_to_cpu(agf->agf_length)))
475 return EFSCORRUPTED;
476
477 xfs_alloc_log_agf(tp, agbp, XFS_AGF_FREEBLKS);
478 return 0;
479}
480
481/*
482 * Allocation group level functions.
483 */
484
485/*
486 * Allocate a variable extent in the allocation group agno.
487 * Type and bno are used to determine where in the allocation group the
488 * extent will start.
489 * Extent's length (returned in *len) will be between minlen and maxlen,
490 * and of the form k * prod + mod unless there's nothing that large.
491 * Return the starting a.g. block, or NULLAGBLOCK if we can't do it.
492 */
493STATIC int /* error */
494xfs_alloc_ag_vextent(
495 xfs_alloc_arg_t *args) /* argument structure for allocation */
496{
497 int error=0;
498
499 ASSERT(args->minlen > 0);
500 ASSERT(args->maxlen > 0);
501 ASSERT(args->minlen <= args->maxlen);
502 ASSERT(args->mod < args->prod);
503 ASSERT(args->alignment > 0);
504 /*
505 * Branch to correct routine based on the type.
506 */
507 args->wasfromfl = 0;
508 switch (args->type) {
509 case XFS_ALLOCTYPE_THIS_AG:
510 error = xfs_alloc_ag_vextent_size(args);
511 break;
512 case XFS_ALLOCTYPE_NEAR_BNO:
513 error = xfs_alloc_ag_vextent_near(args);
514 break;
515 case XFS_ALLOCTYPE_THIS_BNO:
516 error = xfs_alloc_ag_vextent_exact(args);
517 break;
518 default:
519 ASSERT(0);
520 /* NOTREACHED */
521 }
522
523 if (error || args->agbno == NULLAGBLOCK)
524 return error;
525
526 ASSERT(args->len >= args->minlen);
527 ASSERT(args->len <= args->maxlen);
528 ASSERT(!args->wasfromfl || !args->isfl);
529 ASSERT(args->agbno % args->alignment == 0);
530
531 if (!args->wasfromfl) {
532 error = xfs_alloc_update_counters(args->tp, args->pag,
533 args->agbp,
534 -((long)(args->len)));
535 if (error)
536 return error;
537
538 ASSERT(!xfs_alloc_busy_search(args->mp, args->agno,
539 args->agbno, args->len));
540 }
541
542 if (!args->isfl) {
543 xfs_trans_mod_sb(args->tp, args->wasdel ?
544 XFS_TRANS_SB_RES_FDBLOCKS :
545 XFS_TRANS_SB_FDBLOCKS,
546 -((long)(args->len)));
547 }
548
549 XFS_STATS_INC(xs_allocx);
550 XFS_STATS_ADD(xs_allocb, args->len);
551 return error;
552}
553
554/*
555 * Allocate a variable extent at exactly agno/bno.
556 * Extent's length (returned in *len) will be between minlen and maxlen,
557 * and of the form k * prod + mod unless there's nothing that large.
558 * Return the starting a.g. block (bno), or NULLAGBLOCK if we can't do it.
559 */
560STATIC int /* error */
561xfs_alloc_ag_vextent_exact(
562 xfs_alloc_arg_t *args) /* allocation argument structure */
563{
564 xfs_btree_cur_t *bno_cur;/* by block-number btree cursor */
565 xfs_btree_cur_t *cnt_cur;/* by count btree cursor */
566 int error;
567 xfs_agblock_t fbno; /* start block of found extent */
568 xfs_extlen_t flen; /* length of found extent */
569 xfs_agblock_t tbno; /* start block of trimmed extent */
570 xfs_extlen_t tlen; /* length of trimmed extent */
571 xfs_agblock_t tend; /* end block of trimmed extent */
572 int i; /* success/failure of operation */
573
574 ASSERT(args->alignment == 1);
575
576 /*
577 * Allocate/initialize a cursor for the by-number freespace btree.
578 */
579 bno_cur = xfs_allocbt_init_cursor(args->mp, args->tp, args->agbp,
580 args->agno, XFS_BTNUM_BNO);
581
582 /*
583 * Lookup bno and minlen in the btree (minlen is irrelevant, really).
584 * Look for the closest free block <= bno, it must contain bno
585 * if any free block does.
586 */
587 error = xfs_alloc_lookup_le(bno_cur, args->agbno, args->minlen, &i);
588 if (error)
589 goto error0;
590 if (!i)
591 goto not_found;
592
593 /*
594 * Grab the freespace record.
595 */
596 error = xfs_alloc_get_rec(bno_cur, &fbno, &flen, &i);
597 if (error)
598 goto error0;
599 XFS_WANT_CORRUPTED_GOTO(i == 1, error0);
600 ASSERT(fbno <= args->agbno);
601
602 /*
603 * Check for overlapping busy extents.
604 */
605 xfs_alloc_busy_trim(args, fbno, flen, &tbno, &tlen);
606
607 /*
608 * Give up if the start of the extent is busy, or the freespace isn't
609 * long enough for the minimum request.
610 */
611 if (tbno > args->agbno)
612 goto not_found;
613 if (tlen < args->minlen)
614 goto not_found;
615 tend = tbno + tlen;
616 if (tend < args->agbno + args->minlen)
617 goto not_found;
618
619 /*
620 * End of extent will be smaller of the freespace end and the
621 * maximal requested end.
622 *
623 * Fix the length according to mod and prod if given.
624 */
625 args->len = XFS_AGBLOCK_MIN(tend, args->agbno + args->maxlen)
626 - args->agbno;
627 xfs_alloc_fix_len(args);
628 if (!xfs_alloc_fix_minleft(args))
629 goto not_found;
630
631 ASSERT(args->agbno + args->len <= tend);
632
633 /*
634 * We are allocating agbno for args->len
635 * Allocate/initialize a cursor for the by-size btree.
636 */
637 cnt_cur = xfs_allocbt_init_cursor(args->mp, args->tp, args->agbp,
638 args->agno, XFS_BTNUM_CNT);
639 ASSERT(args->agbno + args->len <=
640 be32_to_cpu(XFS_BUF_TO_AGF(args->agbp)->agf_length));
641 error = xfs_alloc_fixup_trees(cnt_cur, bno_cur, fbno, flen, args->agbno,
642 args->len, XFSA_FIXUP_BNO_OK);
643 if (error) {
644 xfs_btree_del_cursor(cnt_cur, XFS_BTREE_ERROR);
645 goto error0;
646 }
647
648 xfs_btree_del_cursor(bno_cur, XFS_BTREE_NOERROR);
649 xfs_btree_del_cursor(cnt_cur, XFS_BTREE_NOERROR);
650
651 args->wasfromfl = 0;
652 trace_xfs_alloc_exact_done(args);
653 return 0;
654
655not_found:
656 /* Didn't find it, return null. */
657 xfs_btree_del_cursor(bno_cur, XFS_BTREE_NOERROR);
658 args->agbno = NULLAGBLOCK;
659 trace_xfs_alloc_exact_notfound(args);
660 return 0;
661
662error0:
663 xfs_btree_del_cursor(bno_cur, XFS_BTREE_ERROR);
664 trace_xfs_alloc_exact_error(args);
665 return error;
666}
667
668/*
669 * Search the btree in a given direction via the search cursor and compare
670 * the records found against the good extent we've already found.
671 */
672STATIC int
673xfs_alloc_find_best_extent(
674 struct xfs_alloc_arg *args, /* allocation argument structure */
675 struct xfs_btree_cur **gcur, /* good cursor */
676 struct xfs_btree_cur **scur, /* searching cursor */
677 xfs_agblock_t gdiff, /* difference for search comparison */
678 xfs_agblock_t *sbno, /* extent found by search */
679 xfs_extlen_t *slen, /* extent length */
680 xfs_agblock_t *sbnoa, /* aligned extent found by search */
681 xfs_extlen_t *slena, /* aligned extent length */
682 int dir) /* 0 = search right, 1 = search left */
683{
684 xfs_agblock_t new;
685 xfs_agblock_t sdiff;
686 int error;
687 int i;
688
689 /* The good extent is perfect, no need to search. */
690 if (!gdiff)
691 goto out_use_good;
692
693 /*
694 * Look until we find a better one, run out of space or run off the end.
695 */
696 do {
697 error = xfs_alloc_get_rec(*scur, sbno, slen, &i);
698 if (error)
699 goto error0;
700 XFS_WANT_CORRUPTED_GOTO(i == 1, error0);
701 xfs_alloc_compute_aligned(args, *sbno, *slen, sbnoa, slena);
702
703 /*
704 * The good extent is closer than this one.
705 */
706 if (!dir) {
707 if (*sbnoa >= args->agbno + gdiff)
708 goto out_use_good;
709 } else {
710 if (*sbnoa <= args->agbno - gdiff)
711 goto out_use_good;
712 }
713
714 /*
715 * Same distance, compare length and pick the best.
716 */
717 if (*slena >= args->minlen) {
718 args->len = XFS_EXTLEN_MIN(*slena, args->maxlen);
719 xfs_alloc_fix_len(args);
720
721 sdiff = xfs_alloc_compute_diff(args->agbno, args->len,
722 args->alignment, *sbnoa,
723 *slena, &new);
724
725 /*
726 * Choose closer size and invalidate other cursor.
727 */
728 if (sdiff < gdiff)
729 goto out_use_search;
730 goto out_use_good;
731 }
732
733 if (!dir)
734 error = xfs_btree_increment(*scur, 0, &i);
735 else
736 error = xfs_btree_decrement(*scur, 0, &i);
737 if (error)
738 goto error0;
739 } while (i);
740
741out_use_good:
742 xfs_btree_del_cursor(*scur, XFS_BTREE_NOERROR);
743 *scur = NULL;
744 return 0;
745
746out_use_search:
747 xfs_btree_del_cursor(*gcur, XFS_BTREE_NOERROR);
748 *gcur = NULL;
749 return 0;
750
751error0:
752 /* caller invalidates cursors */
753 return error;
754}
755
756/*
757 * Allocate a variable extent near bno in the allocation group agno.
758 * Extent's length (returned in len) will be between minlen and maxlen,
759 * and of the form k * prod + mod unless there's nothing that large.
760 * Return the starting a.g. block, or NULLAGBLOCK if we can't do it.
761 */
762STATIC int /* error */
763xfs_alloc_ag_vextent_near(
764 xfs_alloc_arg_t *args) /* allocation argument structure */
765{
766 xfs_btree_cur_t *bno_cur_gt; /* cursor for bno btree, right side */
767 xfs_btree_cur_t *bno_cur_lt; /* cursor for bno btree, left side */
768 xfs_btree_cur_t *cnt_cur; /* cursor for count btree */
769 xfs_agblock_t gtbno; /* start bno of right side entry */
770 xfs_agblock_t gtbnoa; /* aligned ... */
771 xfs_extlen_t gtdiff; /* difference to right side entry */
772 xfs_extlen_t gtlen; /* length of right side entry */
773 xfs_extlen_t gtlena; /* aligned ... */
774 xfs_agblock_t gtnew; /* useful start bno of right side */
775 int error; /* error code */
776 int i; /* result code, temporary */
777 int j; /* result code, temporary */
778 xfs_agblock_t ltbno; /* start bno of left side entry */
779 xfs_agblock_t ltbnoa; /* aligned ... */
780 xfs_extlen_t ltdiff; /* difference to left side entry */
781 xfs_extlen_t ltlen; /* length of left side entry */
782 xfs_extlen_t ltlena; /* aligned ... */
783 xfs_agblock_t ltnew; /* useful start bno of left side */
784 xfs_extlen_t rlen; /* length of returned extent */
785 int forced = 0;
786#if defined(DEBUG) && defined(__KERNEL__)
787 /*
788 * Randomly don't execute the first algorithm.
789 */
790 int dofirst; /* set to do first algorithm */
791
792 dofirst = random32() & 1;
793#endif
794
795restart:
796 bno_cur_lt = NULL;
797 bno_cur_gt = NULL;
798 ltlen = 0;
799 gtlena = 0;
800 ltlena = 0;
801
802 /*
803 * Get a cursor for the by-size btree.
804 */
805 cnt_cur = xfs_allocbt_init_cursor(args->mp, args->tp, args->agbp,
806 args->agno, XFS_BTNUM_CNT);
807
808 /*
809 * See if there are any free extents as big as maxlen.
810 */
811 if ((error = xfs_alloc_lookup_ge(cnt_cur, 0, args->maxlen, &i)))
812 goto error0;
813 /*
814 * If none, then pick up the last entry in the tree unless the
815 * tree is empty.
816 */
817 if (!i) {
818 if ((error = xfs_alloc_ag_vextent_small(args, cnt_cur, <bno,
819 <len, &i)))
820 goto error0;
821 if (i == 0 || ltlen == 0) {
822 xfs_btree_del_cursor(cnt_cur, XFS_BTREE_NOERROR);
823 trace_xfs_alloc_near_noentry(args);
824 return 0;
825 }
826 ASSERT(i == 1);
827 }
828 args->wasfromfl = 0;
829
830 /*
831 * First algorithm.
832 * If the requested extent is large wrt the freespaces available
833 * in this a.g., then the cursor will be pointing to a btree entry
834 * near the right edge of the tree. If it's in the last btree leaf
835 * block, then we just examine all the entries in that block
836 * that are big enough, and pick the best one.
837 * This is written as a while loop so we can break out of it,
838 * but we never loop back to the top.
839 */
840 while (xfs_btree_islastblock(cnt_cur, 0)) {
841 xfs_extlen_t bdiff;
842 int besti=0;
843 xfs_extlen_t blen=0;
844 xfs_agblock_t bnew=0;
845
846#if defined(DEBUG) && defined(__KERNEL__)
847 if (!dofirst)
848 break;
849#endif
850 /*
851 * Start from the entry that lookup found, sequence through
852 * all larger free blocks. If we're actually pointing at a
853 * record smaller than maxlen, go to the start of this block,
854 * and skip all those smaller than minlen.
855 */
856 if (ltlen || args->alignment > 1) {
857 cnt_cur->bc_ptrs[0] = 1;
858 do {
859 if ((error = xfs_alloc_get_rec(cnt_cur, <bno,
860 <len, &i)))
861 goto error0;
862 XFS_WANT_CORRUPTED_GOTO(i == 1, error0);
863 if (ltlen >= args->minlen)
864 break;
865 if ((error = xfs_btree_increment(cnt_cur, 0, &i)))
866 goto error0;
867 } while (i);
868 ASSERT(ltlen >= args->minlen);
869 if (!i)
870 break;
871 }
872 i = cnt_cur->bc_ptrs[0];
873 for (j = 1, blen = 0, bdiff = 0;
874 !error && j && (blen < args->maxlen || bdiff > 0);
875 error = xfs_btree_increment(cnt_cur, 0, &j)) {
876 /*
877 * For each entry, decide if it's better than
878 * the previous best entry.
879 */
880 if ((error = xfs_alloc_get_rec(cnt_cur, <bno, <len, &i)))
881 goto error0;
882 XFS_WANT_CORRUPTED_GOTO(i == 1, error0);
883 xfs_alloc_compute_aligned(args, ltbno, ltlen,
884 <bnoa, <lena);
885 if (ltlena < args->minlen)
886 continue;
887 args->len = XFS_EXTLEN_MIN(ltlena, args->maxlen);
888 xfs_alloc_fix_len(args);
889 ASSERT(args->len >= args->minlen);
890 if (args->len < blen)
891 continue;
892 ltdiff = xfs_alloc_compute_diff(args->agbno, args->len,
893 args->alignment, ltbnoa, ltlena, <new);
894 if (ltnew != NULLAGBLOCK &&
895 (args->len > blen || ltdiff < bdiff)) {
896 bdiff = ltdiff;
897 bnew = ltnew;
898 blen = args->len;
899 besti = cnt_cur->bc_ptrs[0];
900 }
901 }
902 /*
903 * It didn't work. We COULD be in a case where
904 * there's a good record somewhere, so try again.
905 */
906 if (blen == 0)
907 break;
908 /*
909 * Point at the best entry, and retrieve it again.
910 */
911 cnt_cur->bc_ptrs[0] = besti;
912 if ((error = xfs_alloc_get_rec(cnt_cur, <bno, <len, &i)))
913 goto error0;
914 XFS_WANT_CORRUPTED_GOTO(i == 1, error0);
915 ASSERT(ltbno + ltlen <= be32_to_cpu(XFS_BUF_TO_AGF(args->agbp)->agf_length));
916 args->len = blen;
917 if (!xfs_alloc_fix_minleft(args)) {
918 xfs_btree_del_cursor(cnt_cur, XFS_BTREE_NOERROR);
919 trace_xfs_alloc_near_nominleft(args);
920 return 0;
921 }
922 blen = args->len;
923 /*
924 * We are allocating starting at bnew for blen blocks.
925 */
926 args->agbno = bnew;
927 ASSERT(bnew >= ltbno);
928 ASSERT(bnew + blen <= ltbno + ltlen);
929 /*
930 * Set up a cursor for the by-bno tree.
931 */
932 bno_cur_lt = xfs_allocbt_init_cursor(args->mp, args->tp,
933 args->agbp, args->agno, XFS_BTNUM_BNO);
934 /*
935 * Fix up the btree entries.
936 */
937 if ((error = xfs_alloc_fixup_trees(cnt_cur, bno_cur_lt, ltbno,
938 ltlen, bnew, blen, XFSA_FIXUP_CNT_OK)))
939 goto error0;
940 xfs_btree_del_cursor(cnt_cur, XFS_BTREE_NOERROR);
941 xfs_btree_del_cursor(bno_cur_lt, XFS_BTREE_NOERROR);
942
943 trace_xfs_alloc_near_first(args);
944 return 0;
945 }
946 /*
947 * Second algorithm.
948 * Search in the by-bno tree to the left and to the right
949 * simultaneously, until in each case we find a space big enough,
950 * or run into the edge of the tree. When we run into the edge,
951 * we deallocate that cursor.
952 * If both searches succeed, we compare the two spaces and pick
953 * the better one.
954 * With alignment, it's possible for both to fail; the upper
955 * level algorithm that picks allocation groups for allocations
956 * is not supposed to do this.
957 */
958 /*
959 * Allocate and initialize the cursor for the leftward search.
960 */
961 bno_cur_lt = xfs_allocbt_init_cursor(args->mp, args->tp, args->agbp,
962 args->agno, XFS_BTNUM_BNO);
963 /*
964 * Lookup <= bno to find the leftward search's starting point.
965 */
966 if ((error = xfs_alloc_lookup_le(bno_cur_lt, args->agbno, args->maxlen, &i)))
967 goto error0;
968 if (!i) {
969 /*
970 * Didn't find anything; use this cursor for the rightward
971 * search.
972 */
973 bno_cur_gt = bno_cur_lt;
974 bno_cur_lt = NULL;
975 }
976 /*
977 * Found something. Duplicate the cursor for the rightward search.
978 */
979 else if ((error = xfs_btree_dup_cursor(bno_cur_lt, &bno_cur_gt)))
980 goto error0;
981 /*
982 * Increment the cursor, so we will point at the entry just right
983 * of the leftward entry if any, or to the leftmost entry.
984 */
985 if ((error = xfs_btree_increment(bno_cur_gt, 0, &i)))
986 goto error0;
987 if (!i) {
988 /*
989 * It failed, there are no rightward entries.
990 */
991 xfs_btree_del_cursor(bno_cur_gt, XFS_BTREE_NOERROR);
992 bno_cur_gt = NULL;
993 }
994 /*
995 * Loop going left with the leftward cursor, right with the
996 * rightward cursor, until either both directions give up or
997 * we find an entry at least as big as minlen.
998 */
999 do {
1000 if (bno_cur_lt) {
1001 if ((error = xfs_alloc_get_rec(bno_cur_lt, <bno, <len, &i)))
1002 goto error0;
1003 XFS_WANT_CORRUPTED_GOTO(i == 1, error0);
1004 xfs_alloc_compute_aligned(args, ltbno, ltlen,
1005 <bnoa, <lena);
1006 if (ltlena >= args->minlen)
1007 break;
1008 if ((error = xfs_btree_decrement(bno_cur_lt, 0, &i)))
1009 goto error0;
1010 if (!i) {
1011 xfs_btree_del_cursor(bno_cur_lt,
1012 XFS_BTREE_NOERROR);
1013 bno_cur_lt = NULL;
1014 }
1015 }
1016 if (bno_cur_gt) {
1017 if ((error = xfs_alloc_get_rec(bno_cur_gt, >bno, >len, &i)))
1018 goto error0;
1019 XFS_WANT_CORRUPTED_GOTO(i == 1, error0);
1020 xfs_alloc_compute_aligned(args, gtbno, gtlen,
1021 >bnoa, >lena);
1022 if (gtlena >= args->minlen)
1023 break;
1024 if ((error = xfs_btree_increment(bno_cur_gt, 0, &i)))
1025 goto error0;
1026 if (!i) {
1027 xfs_btree_del_cursor(bno_cur_gt,
1028 XFS_BTREE_NOERROR);
1029 bno_cur_gt = NULL;
1030 }
1031 }
1032 } while (bno_cur_lt || bno_cur_gt);
1033
1034 /*
1035 * Got both cursors still active, need to find better entry.
1036 */
1037 if (bno_cur_lt && bno_cur_gt) {
1038 if (ltlena >= args->minlen) {
1039 /*
1040 * Left side is good, look for a right side entry.
1041 */
1042 args->len = XFS_EXTLEN_MIN(ltlena, args->maxlen);
1043 xfs_alloc_fix_len(args);
1044 ltdiff = xfs_alloc_compute_diff(args->agbno, args->len,
1045 args->alignment, ltbnoa, ltlena, <new);
1046
1047 error = xfs_alloc_find_best_extent(args,
1048 &bno_cur_lt, &bno_cur_gt,
1049 ltdiff, >bno, >len,
1050 >bnoa, >lena,
1051 0 /* search right */);
1052 } else {
1053 ASSERT(gtlena >= args->minlen);
1054
1055 /*
1056 * Right side is good, look for a left side entry.
1057 */
1058 args->len = XFS_EXTLEN_MIN(gtlena, args->maxlen);
1059 xfs_alloc_fix_len(args);
1060 gtdiff = xfs_alloc_compute_diff(args->agbno, args->len,
1061 args->alignment, gtbnoa, gtlena, >new);
1062
1063 error = xfs_alloc_find_best_extent(args,
1064 &bno_cur_gt, &bno_cur_lt,
1065 gtdiff, <bno, <len,
1066 <bnoa, <lena,
1067 1 /* search left */);
1068 }
1069
1070 if (error)
1071 goto error0;
1072 }
1073
1074 /*
1075 * If we couldn't get anything, give up.
1076 */
1077 if (bno_cur_lt == NULL && bno_cur_gt == NULL) {
1078 if (!forced++) {
1079 trace_xfs_alloc_near_busy(args);
1080 xfs_log_force(args->mp, XFS_LOG_SYNC);
1081 goto restart;
1082 }
1083
1084 trace_xfs_alloc_size_neither(args);
1085 args->agbno = NULLAGBLOCK;
1086 return 0;
1087 }
1088
1089 /*
1090 * At this point we have selected a freespace entry, either to the
1091 * left or to the right. If it's on the right, copy all the
1092 * useful variables to the "left" set so we only have one
1093 * copy of this code.
1094 */
1095 if (bno_cur_gt) {
1096 bno_cur_lt = bno_cur_gt;
1097 bno_cur_gt = NULL;
1098 ltbno = gtbno;
1099 ltbnoa = gtbnoa;
1100 ltlen = gtlen;
1101 ltlena = gtlena;
1102 j = 1;
1103 } else
1104 j = 0;
1105
1106 /*
1107 * Fix up the length and compute the useful address.
1108 */
1109 args->len = XFS_EXTLEN_MIN(ltlena, args->maxlen);
1110 xfs_alloc_fix_len(args);
1111 if (!xfs_alloc_fix_minleft(args)) {
1112 trace_xfs_alloc_near_nominleft(args);
1113 xfs_btree_del_cursor(bno_cur_lt, XFS_BTREE_NOERROR);
1114 xfs_btree_del_cursor(cnt_cur, XFS_BTREE_NOERROR);
1115 return 0;
1116 }
1117 rlen = args->len;
1118 (void)xfs_alloc_compute_diff(args->agbno, rlen, args->alignment,
1119 ltbnoa, ltlena, <new);
1120 ASSERT(ltnew >= ltbno);
1121 ASSERT(ltnew + rlen <= ltbnoa + ltlena);
1122 ASSERT(ltnew + rlen <= be32_to_cpu(XFS_BUF_TO_AGF(args->agbp)->agf_length));
1123 args->agbno = ltnew;
1124
1125 if ((error = xfs_alloc_fixup_trees(cnt_cur, bno_cur_lt, ltbno, ltlen,
1126 ltnew, rlen, XFSA_FIXUP_BNO_OK)))
1127 goto error0;
1128
1129 if (j)
1130 trace_xfs_alloc_near_greater(args);
1131 else
1132 trace_xfs_alloc_near_lesser(args);
1133
1134 xfs_btree_del_cursor(cnt_cur, XFS_BTREE_NOERROR);
1135 xfs_btree_del_cursor(bno_cur_lt, XFS_BTREE_NOERROR);
1136 return 0;
1137
1138 error0:
1139 trace_xfs_alloc_near_error(args);
1140 if (cnt_cur != NULL)
1141 xfs_btree_del_cursor(cnt_cur, XFS_BTREE_ERROR);
1142 if (bno_cur_lt != NULL)
1143 xfs_btree_del_cursor(bno_cur_lt, XFS_BTREE_ERROR);
1144 if (bno_cur_gt != NULL)
1145 xfs_btree_del_cursor(bno_cur_gt, XFS_BTREE_ERROR);
1146 return error;
1147}
1148
1149/*
1150 * Allocate a variable extent anywhere in the allocation group agno.
1151 * Extent's length (returned in len) will be between minlen and maxlen,
1152 * and of the form k * prod + mod unless there's nothing that large.
1153 * Return the starting a.g. block, or NULLAGBLOCK if we can't do it.
1154 */
1155STATIC int /* error */
1156xfs_alloc_ag_vextent_size(
1157 xfs_alloc_arg_t *args) /* allocation argument structure */
1158{
1159 xfs_btree_cur_t *bno_cur; /* cursor for bno btree */
1160 xfs_btree_cur_t *cnt_cur; /* cursor for cnt btree */
1161 int error; /* error result */
1162 xfs_agblock_t fbno; /* start of found freespace */
1163 xfs_extlen_t flen; /* length of found freespace */
1164 int i; /* temp status variable */
1165 xfs_agblock_t rbno; /* returned block number */
1166 xfs_extlen_t rlen; /* length of returned extent */
1167 int forced = 0;
1168
1169restart:
1170 /*
1171 * Allocate and initialize a cursor for the by-size btree.
1172 */
1173 cnt_cur = xfs_allocbt_init_cursor(args->mp, args->tp, args->agbp,
1174 args->agno, XFS_BTNUM_CNT);
1175 bno_cur = NULL;
1176
1177 /*
1178 * Look for an entry >= maxlen+alignment-1 blocks.
1179 */
1180 if ((error = xfs_alloc_lookup_ge(cnt_cur, 0,
1181 args->maxlen + args->alignment - 1, &i)))
1182 goto error0;
1183
1184 /*
1185 * If none or we have busy extents that we cannot allocate from, then
1186 * we have to settle for a smaller extent. In the case that there are
1187 * no large extents, this will return the last entry in the tree unless
1188 * the tree is empty. In the case that there are only busy large
1189 * extents, this will return the largest small extent unless there
1190 * are no smaller extents available.
1191 */
1192 if (!i || forced > 1) {
1193 error = xfs_alloc_ag_vextent_small(args, cnt_cur,
1194 &fbno, &flen, &i);
1195 if (error)
1196 goto error0;
1197 if (i == 0 || flen == 0) {
1198 xfs_btree_del_cursor(cnt_cur, XFS_BTREE_NOERROR);
1199 trace_xfs_alloc_size_noentry(args);
1200 return 0;
1201 }
1202 ASSERT(i == 1);
1203 xfs_alloc_compute_aligned(args, fbno, flen, &rbno, &rlen);
1204 } else {
1205 /*
1206 * Search for a non-busy extent that is large enough.
1207 * If we are at low space, don't check, or if we fall of
1208 * the end of the btree, turn off the busy check and
1209 * restart.
1210 */
1211 for (;;) {
1212 error = xfs_alloc_get_rec(cnt_cur, &fbno, &flen, &i);
1213 if (error)
1214 goto error0;
1215 XFS_WANT_CORRUPTED_GOTO(i == 1, error0);
1216
1217 xfs_alloc_compute_aligned(args, fbno, flen,
1218 &rbno, &rlen);
1219
1220 if (rlen >= args->maxlen)
1221 break;
1222
1223 error = xfs_btree_increment(cnt_cur, 0, &i);
1224 if (error)
1225 goto error0;
1226 if (i == 0) {
1227 /*
1228 * Our only valid extents must have been busy.
1229 * Make it unbusy by forcing the log out and
1230 * retrying. If we've been here before, forcing
1231 * the log isn't making the extents available,
1232 * which means they have probably been freed in
1233 * this transaction. In that case, we have to
1234 * give up on them and we'll attempt a minlen
1235 * allocation the next time around.
1236 */
1237 xfs_btree_del_cursor(cnt_cur,
1238 XFS_BTREE_NOERROR);
1239 trace_xfs_alloc_size_busy(args);
1240 if (!forced++)
1241 xfs_log_force(args->mp, XFS_LOG_SYNC);
1242 goto restart;
1243 }
1244 }
1245 }
1246
1247 /*
1248 * In the first case above, we got the last entry in the
1249 * by-size btree. Now we check to see if the space hits maxlen
1250 * once aligned; if not, we search left for something better.
1251 * This can't happen in the second case above.
1252 */
1253 rlen = XFS_EXTLEN_MIN(args->maxlen, rlen);
1254 XFS_WANT_CORRUPTED_GOTO(rlen == 0 ||
1255 (rlen <= flen && rbno + rlen <= fbno + flen), error0);
1256 if (rlen < args->maxlen) {
1257 xfs_agblock_t bestfbno;
1258 xfs_extlen_t bestflen;
1259 xfs_agblock_t bestrbno;
1260 xfs_extlen_t bestrlen;
1261
1262 bestrlen = rlen;
1263 bestrbno = rbno;
1264 bestflen = flen;
1265 bestfbno = fbno;
1266 for (;;) {
1267 if ((error = xfs_btree_decrement(cnt_cur, 0, &i)))
1268 goto error0;
1269 if (i == 0)
1270 break;
1271 if ((error = xfs_alloc_get_rec(cnt_cur, &fbno, &flen,
1272 &i)))
1273 goto error0;
1274 XFS_WANT_CORRUPTED_GOTO(i == 1, error0);
1275 if (flen < bestrlen)
1276 break;
1277 xfs_alloc_compute_aligned(args, fbno, flen,
1278 &rbno, &rlen);
1279 rlen = XFS_EXTLEN_MIN(args->maxlen, rlen);
1280 XFS_WANT_CORRUPTED_GOTO(rlen == 0 ||
1281 (rlen <= flen && rbno + rlen <= fbno + flen),
1282 error0);
1283 if (rlen > bestrlen) {
1284 bestrlen = rlen;
1285 bestrbno = rbno;
1286 bestflen = flen;
1287 bestfbno = fbno;
1288 if (rlen == args->maxlen)
1289 break;
1290 }
1291 }
1292 if ((error = xfs_alloc_lookup_eq(cnt_cur, bestfbno, bestflen,
1293 &i)))
1294 goto error0;
1295 XFS_WANT_CORRUPTED_GOTO(i == 1, error0);
1296 rlen = bestrlen;
1297 rbno = bestrbno;
1298 flen = bestflen;
1299 fbno = bestfbno;
1300 }
1301 args->wasfromfl = 0;
1302 /*
1303 * Fix up the length.
1304 */
1305 args->len = rlen;
1306 if (rlen < args->minlen) {
1307 if (!forced++) {
1308 xfs_btree_del_cursor(cnt_cur, XFS_BTREE_NOERROR);
1309 trace_xfs_alloc_size_busy(args);
1310 xfs_log_force(args->mp, XFS_LOG_SYNC);
1311 goto restart;
1312 }
1313 goto out_nominleft;
1314 }
1315 xfs_alloc_fix_len(args);
1316
1317 if (!xfs_alloc_fix_minleft(args))
1318 goto out_nominleft;
1319 rlen = args->len;
1320 XFS_WANT_CORRUPTED_GOTO(rlen <= flen, error0);
1321 /*
1322 * Allocate and initialize a cursor for the by-block tree.
1323 */
1324 bno_cur = xfs_allocbt_init_cursor(args->mp, args->tp, args->agbp,
1325 args->agno, XFS_BTNUM_BNO);
1326 if ((error = xfs_alloc_fixup_trees(cnt_cur, bno_cur, fbno, flen,
1327 rbno, rlen, XFSA_FIXUP_CNT_OK)))
1328 goto error0;
1329 xfs_btree_del_cursor(cnt_cur, XFS_BTREE_NOERROR);
1330 xfs_btree_del_cursor(bno_cur, XFS_BTREE_NOERROR);
1331 cnt_cur = bno_cur = NULL;
1332 args->len = rlen;
1333 args->agbno = rbno;
1334 XFS_WANT_CORRUPTED_GOTO(
1335 args->agbno + args->len <=
1336 be32_to_cpu(XFS_BUF_TO_AGF(args->agbp)->agf_length),
1337 error0);
1338 trace_xfs_alloc_size_done(args);
1339 return 0;
1340
1341error0:
1342 trace_xfs_alloc_size_error(args);
1343 if (cnt_cur)
1344 xfs_btree_del_cursor(cnt_cur, XFS_BTREE_ERROR);
1345 if (bno_cur)
1346 xfs_btree_del_cursor(bno_cur, XFS_BTREE_ERROR);
1347 return error;
1348
1349out_nominleft:
1350 xfs_btree_del_cursor(cnt_cur, XFS_BTREE_NOERROR);
1351 trace_xfs_alloc_size_nominleft(args);
1352 args->agbno = NULLAGBLOCK;
1353 return 0;
1354}
1355
1356/*
1357 * Deal with the case where only small freespaces remain.
1358 * Either return the contents of the last freespace record,
1359 * or allocate space from the freelist if there is nothing in the tree.
1360 */
1361STATIC int /* error */
1362xfs_alloc_ag_vextent_small(
1363 xfs_alloc_arg_t *args, /* allocation argument structure */
1364 xfs_btree_cur_t *ccur, /* by-size cursor */
1365 xfs_agblock_t *fbnop, /* result block number */
1366 xfs_extlen_t *flenp, /* result length */
1367 int *stat) /* status: 0-freelist, 1-normal/none */
1368{
1369 int error;
1370 xfs_agblock_t fbno;
1371 xfs_extlen_t flen;
1372 int i;
1373
1374 if ((error = xfs_btree_decrement(ccur, 0, &i)))
1375 goto error0;
1376 if (i) {
1377 if ((error = xfs_alloc_get_rec(ccur, &fbno, &flen, &i)))
1378 goto error0;
1379 XFS_WANT_CORRUPTED_GOTO(i == 1, error0);
1380 }
1381 /*
1382 * Nothing in the btree, try the freelist. Make sure
1383 * to respect minleft even when pulling from the
1384 * freelist.
1385 */
1386 else if (args->minlen == 1 && args->alignment == 1 && !args->isfl &&
1387 (be32_to_cpu(XFS_BUF_TO_AGF(args->agbp)->agf_flcount)
1388 > args->minleft)) {
1389 error = xfs_alloc_get_freelist(args->tp, args->agbp, &fbno, 0);
1390 if (error)
1391 goto error0;
1392 if (fbno != NULLAGBLOCK) {
1393 xfs_alloc_busy_reuse(args->mp, args->agno, fbno, 1,
1394 args->userdata);
1395
1396 if (args->userdata) {
1397 xfs_buf_t *bp;
1398
1399 bp = xfs_btree_get_bufs(args->mp, args->tp,
1400 args->agno, fbno, 0);
1401 xfs_trans_binval(args->tp, bp);
1402 }
1403 args->len = 1;
1404 args->agbno = fbno;
1405 XFS_WANT_CORRUPTED_GOTO(
1406 args->agbno + args->len <=
1407 be32_to_cpu(XFS_BUF_TO_AGF(args->agbp)->agf_length),
1408 error0);
1409 args->wasfromfl = 1;
1410 trace_xfs_alloc_small_freelist(args);
1411 *stat = 0;
1412 return 0;
1413 }
1414 /*
1415 * Nothing in the freelist.
1416 */
1417 else
1418 flen = 0;
1419 }
1420 /*
1421 * Can't allocate from the freelist for some reason.
1422 */
1423 else {
1424 fbno = NULLAGBLOCK;
1425 flen = 0;
1426 }
1427 /*
1428 * Can't do the allocation, give up.
1429 */
1430 if (flen < args->minlen) {
1431 args->agbno = NULLAGBLOCK;
1432 trace_xfs_alloc_small_notenough(args);
1433 flen = 0;
1434 }
1435 *fbnop = fbno;
1436 *flenp = flen;
1437 *stat = 1;
1438 trace_xfs_alloc_small_done(args);
1439 return 0;
1440
1441error0:
1442 trace_xfs_alloc_small_error(args);
1443 return error;
1444}
1445
1446/*
1447 * Free the extent starting at agno/bno for length.
1448 */
1449STATIC int /* error */
1450xfs_free_ag_extent(
1451 xfs_trans_t *tp, /* transaction pointer */
1452 xfs_buf_t *agbp, /* buffer for a.g. freelist header */
1453 xfs_agnumber_t agno, /* allocation group number */
1454 xfs_agblock_t bno, /* starting block number */
1455 xfs_extlen_t len, /* length of extent */
1456 int isfl) /* set if is freelist blocks - no sb acctg */
1457{
1458 xfs_btree_cur_t *bno_cur; /* cursor for by-block btree */
1459 xfs_btree_cur_t *cnt_cur; /* cursor for by-size btree */
1460 int error; /* error return value */
1461 xfs_agblock_t gtbno; /* start of right neighbor block */
1462 xfs_extlen_t gtlen; /* length of right neighbor block */
1463 int haveleft; /* have a left neighbor block */
1464 int haveright; /* have a right neighbor block */
1465 int i; /* temp, result code */
1466 xfs_agblock_t ltbno; /* start of left neighbor block */
1467 xfs_extlen_t ltlen; /* length of left neighbor block */
1468 xfs_mount_t *mp; /* mount point struct for filesystem */
1469 xfs_agblock_t nbno; /* new starting block of freespace */
1470 xfs_extlen_t nlen; /* new length of freespace */
1471 xfs_perag_t *pag; /* per allocation group data */
1472
1473 mp = tp->t_mountp;
1474 /*
1475 * Allocate and initialize a cursor for the by-block btree.
1476 */
1477 bno_cur = xfs_allocbt_init_cursor(mp, tp, agbp, agno, XFS_BTNUM_BNO);
1478 cnt_cur = NULL;
1479 /*
1480 * Look for a neighboring block on the left (lower block numbers)
1481 * that is contiguous with this space.
1482 */
1483 if ((error = xfs_alloc_lookup_le(bno_cur, bno, len, &haveleft)))
1484 goto error0;
1485 if (haveleft) {
1486 /*
1487 * There is a block to our left.
1488 */
1489 if ((error = xfs_alloc_get_rec(bno_cur, <bno, <len, &i)))
1490 goto error0;
1491 XFS_WANT_CORRUPTED_GOTO(i == 1, error0);
1492 /*
1493 * It's not contiguous, though.
1494 */
1495 if (ltbno + ltlen < bno)
1496 haveleft = 0;
1497 else {
1498 /*
1499 * If this failure happens the request to free this
1500 * space was invalid, it's (partly) already free.
1501 * Very bad.
1502 */
1503 XFS_WANT_CORRUPTED_GOTO(ltbno + ltlen <= bno, error0);
1504 }
1505 }
1506 /*
1507 * Look for a neighboring block on the right (higher block numbers)
1508 * that is contiguous with this space.
1509 */
1510 if ((error = xfs_btree_increment(bno_cur, 0, &haveright)))
1511 goto error0;
1512 if (haveright) {
1513 /*
1514 * There is a block to our right.
1515 */
1516 if ((error = xfs_alloc_get_rec(bno_cur, >bno, >len, &i)))
1517 goto error0;
1518 XFS_WANT_CORRUPTED_GOTO(i == 1, error0);
1519 /*
1520 * It's not contiguous, though.
1521 */
1522 if (bno + len < gtbno)
1523 haveright = 0;
1524 else {
1525 /*
1526 * If this failure happens the request to free this
1527 * space was invalid, it's (partly) already free.
1528 * Very bad.
1529 */
1530 XFS_WANT_CORRUPTED_GOTO(gtbno >= bno + len, error0);
1531 }
1532 }
1533 /*
1534 * Now allocate and initialize a cursor for the by-size tree.
1535 */
1536 cnt_cur = xfs_allocbt_init_cursor(mp, tp, agbp, agno, XFS_BTNUM_CNT);
1537 /*
1538 * Have both left and right contiguous neighbors.
1539 * Merge all three into a single free block.
1540 */
1541 if (haveleft && haveright) {
1542 /*
1543 * Delete the old by-size entry on the left.
1544 */
1545 if ((error = xfs_alloc_lookup_eq(cnt_cur, ltbno, ltlen, &i)))
1546 goto error0;
1547 XFS_WANT_CORRUPTED_GOTO(i == 1, error0);
1548 if ((error = xfs_btree_delete(cnt_cur, &i)))
1549 goto error0;
1550 XFS_WANT_CORRUPTED_GOTO(i == 1, error0);
1551 /*
1552 * Delete the old by-size entry on the right.
1553 */
1554 if ((error = xfs_alloc_lookup_eq(cnt_cur, gtbno, gtlen, &i)))
1555 goto error0;
1556 XFS_WANT_CORRUPTED_GOTO(i == 1, error0);
1557 if ((error = xfs_btree_delete(cnt_cur, &i)))
1558 goto error0;
1559 XFS_WANT_CORRUPTED_GOTO(i == 1, error0);
1560 /*
1561 * Delete the old by-block entry for the right block.
1562 */
1563 if ((error = xfs_btree_delete(bno_cur, &i)))
1564 goto error0;
1565 XFS_WANT_CORRUPTED_GOTO(i == 1, error0);
1566 /*
1567 * Move the by-block cursor back to the left neighbor.
1568 */
1569 if ((error = xfs_btree_decrement(bno_cur, 0, &i)))
1570 goto error0;
1571 XFS_WANT_CORRUPTED_GOTO(i == 1, error0);
1572#ifdef DEBUG
1573 /*
1574 * Check that this is the right record: delete didn't
1575 * mangle the cursor.
1576 */
1577 {
1578 xfs_agblock_t xxbno;
1579 xfs_extlen_t xxlen;
1580
1581 if ((error = xfs_alloc_get_rec(bno_cur, &xxbno, &xxlen,
1582 &i)))
1583 goto error0;
1584 XFS_WANT_CORRUPTED_GOTO(
1585 i == 1 && xxbno == ltbno && xxlen == ltlen,
1586 error0);
1587 }
1588#endif
1589 /*
1590 * Update remaining by-block entry to the new, joined block.
1591 */
1592 nbno = ltbno;
1593 nlen = len + ltlen + gtlen;
1594 if ((error = xfs_alloc_update(bno_cur, nbno, nlen)))
1595 goto error0;
1596 }
1597 /*
1598 * Have only a left contiguous neighbor.
1599 * Merge it together with the new freespace.
1600 */
1601 else if (haveleft) {
1602 /*
1603 * Delete the old by-size entry on the left.
1604 */
1605 if ((error = xfs_alloc_lookup_eq(cnt_cur, ltbno, ltlen, &i)))
1606 goto error0;
1607 XFS_WANT_CORRUPTED_GOTO(i == 1, error0);
1608 if ((error = xfs_btree_delete(cnt_cur, &i)))
1609 goto error0;
1610 XFS_WANT_CORRUPTED_GOTO(i == 1, error0);
1611 /*
1612 * Back up the by-block cursor to the left neighbor, and
1613 * update its length.
1614 */
1615 if ((error = xfs_btree_decrement(bno_cur, 0, &i)))
1616 goto error0;
1617 XFS_WANT_CORRUPTED_GOTO(i == 1, error0);
1618 nbno = ltbno;
1619 nlen = len + ltlen;
1620 if ((error = xfs_alloc_update(bno_cur, nbno, nlen)))
1621 goto error0;
1622 }
1623 /*
1624 * Have only a right contiguous neighbor.
1625 * Merge it together with the new freespace.
1626 */
1627 else if (haveright) {
1628 /*
1629 * Delete the old by-size entry on the right.
1630 */
1631 if ((error = xfs_alloc_lookup_eq(cnt_cur, gtbno, gtlen, &i)))
1632 goto error0;
1633 XFS_WANT_CORRUPTED_GOTO(i == 1, error0);
1634 if ((error = xfs_btree_delete(cnt_cur, &i)))
1635 goto error0;
1636 XFS_WANT_CORRUPTED_GOTO(i == 1, error0);
1637 /*
1638 * Update the starting block and length of the right
1639 * neighbor in the by-block tree.
1640 */
1641 nbno = bno;
1642 nlen = len + gtlen;
1643 if ((error = xfs_alloc_update(bno_cur, nbno, nlen)))
1644 goto error0;
1645 }
1646 /*
1647 * No contiguous neighbors.
1648 * Insert the new freespace into the by-block tree.
1649 */
1650 else {
1651 nbno = bno;
1652 nlen = len;
1653 if ((error = xfs_btree_insert(bno_cur, &i)))
1654 goto error0;
1655 XFS_WANT_CORRUPTED_GOTO(i == 1, error0);
1656 }
1657 xfs_btree_del_cursor(bno_cur, XFS_BTREE_NOERROR);
1658 bno_cur = NULL;
1659 /*
1660 * In all cases we need to insert the new freespace in the by-size tree.
1661 */
1662 if ((error = xfs_alloc_lookup_eq(cnt_cur, nbno, nlen, &i)))
1663 goto error0;
1664 XFS_WANT_CORRUPTED_GOTO(i == 0, error0);
1665 if ((error = xfs_btree_insert(cnt_cur, &i)))
1666 goto error0;
1667 XFS_WANT_CORRUPTED_GOTO(i == 1, error0);
1668 xfs_btree_del_cursor(cnt_cur, XFS_BTREE_NOERROR);
1669 cnt_cur = NULL;
1670
1671 /*
1672 * Update the freespace totals in the ag and superblock.
1673 */
1674 pag = xfs_perag_get(mp, agno);
1675 error = xfs_alloc_update_counters(tp, pag, agbp, len);
1676 xfs_perag_put(pag);
1677 if (error)
1678 goto error0;
1679
1680 if (!isfl)
1681 xfs_trans_mod_sb(tp, XFS_TRANS_SB_FDBLOCKS, (long)len);
1682 XFS_STATS_INC(xs_freex);
1683 XFS_STATS_ADD(xs_freeb, len);
1684
1685 trace_xfs_free_extent(mp, agno, bno, len, isfl, haveleft, haveright);
1686
1687 return 0;
1688
1689 error0:
1690 trace_xfs_free_extent(mp, agno, bno, len, isfl, -1, -1);
1691 if (bno_cur)
1692 xfs_btree_del_cursor(bno_cur, XFS_BTREE_ERROR);
1693 if (cnt_cur)
1694 xfs_btree_del_cursor(cnt_cur, XFS_BTREE_ERROR);
1695 return error;
1696}
1697
1698/*
1699 * Visible (exported) allocation/free functions.
1700 * Some of these are used just by xfs_alloc_btree.c and this file.
1701 */
1702
1703/*
1704 * Compute and fill in value of m_ag_maxlevels.
1705 */
1706void
1707xfs_alloc_compute_maxlevels(
1708 xfs_mount_t *mp) /* file system mount structure */
1709{
1710 int level;
1711 uint maxblocks;
1712 uint maxleafents;
1713 int minleafrecs;
1714 int minnoderecs;
1715
1716 maxleafents = (mp->m_sb.sb_agblocks + 1) / 2;
1717 minleafrecs = mp->m_alloc_mnr[0];
1718 minnoderecs = mp->m_alloc_mnr[1];
1719 maxblocks = (maxleafents + minleafrecs - 1) / minleafrecs;
1720 for (level = 1; maxblocks > 1; level++)
1721 maxblocks = (maxblocks + minnoderecs - 1) / minnoderecs;
1722 mp->m_ag_maxlevels = level;
1723}
1724
1725/*
1726 * Find the length of the longest extent in an AG.
1727 */
1728xfs_extlen_t
1729xfs_alloc_longest_free_extent(
1730 struct xfs_mount *mp,
1731 struct xfs_perag *pag)
1732{
1733 xfs_extlen_t need, delta = 0;
1734
1735 need = XFS_MIN_FREELIST_PAG(pag, mp);
1736 if (need > pag->pagf_flcount)
1737 delta = need - pag->pagf_flcount;
1738
1739 if (pag->pagf_longest > delta)
1740 return pag->pagf_longest - delta;
1741 return pag->pagf_flcount > 0 || pag->pagf_longest > 0;
1742}
1743
1744/*
1745 * Decide whether to use this allocation group for this allocation.
1746 * If so, fix up the btree freelist's size.
1747 */
1748STATIC int /* error */
1749xfs_alloc_fix_freelist(
1750 xfs_alloc_arg_t *args, /* allocation argument structure */
1751 int flags) /* XFS_ALLOC_FLAG_... */
1752{
1753 xfs_buf_t *agbp; /* agf buffer pointer */
1754 xfs_agf_t *agf; /* a.g. freespace structure pointer */
1755 xfs_buf_t *agflbp;/* agfl buffer pointer */
1756 xfs_agblock_t bno; /* freelist block */
1757 xfs_extlen_t delta; /* new blocks needed in freelist */
1758 int error; /* error result code */
1759 xfs_extlen_t longest;/* longest extent in allocation group */
1760 xfs_mount_t *mp; /* file system mount point structure */
1761 xfs_extlen_t need; /* total blocks needed in freelist */
1762 xfs_perag_t *pag; /* per-ag information structure */
1763 xfs_alloc_arg_t targs; /* local allocation arguments */
1764 xfs_trans_t *tp; /* transaction pointer */
1765
1766 mp = args->mp;
1767
1768 pag = args->pag;
1769 tp = args->tp;
1770 if (!pag->pagf_init) {
1771 if ((error = xfs_alloc_read_agf(mp, tp, args->agno, flags,
1772 &agbp)))
1773 return error;
1774 if (!pag->pagf_init) {
1775 ASSERT(flags & XFS_ALLOC_FLAG_TRYLOCK);
1776 ASSERT(!(flags & XFS_ALLOC_FLAG_FREEING));
1777 args->agbp = NULL;
1778 return 0;
1779 }
1780 } else
1781 agbp = NULL;
1782
1783 /*
1784 * If this is a metadata preferred pag and we are user data
1785 * then try somewhere else if we are not being asked to
1786 * try harder at this point
1787 */
1788 if (pag->pagf_metadata && args->userdata &&
1789 (flags & XFS_ALLOC_FLAG_TRYLOCK)) {
1790 ASSERT(!(flags & XFS_ALLOC_FLAG_FREEING));
1791 args->agbp = NULL;
1792 return 0;
1793 }
1794
1795 if (!(flags & XFS_ALLOC_FLAG_FREEING)) {
1796 /*
1797 * If it looks like there isn't a long enough extent, or enough
1798 * total blocks, reject it.
1799 */
1800 need = XFS_MIN_FREELIST_PAG(pag, mp);
1801 longest = xfs_alloc_longest_free_extent(mp, pag);
1802 if ((args->minlen + args->alignment + args->minalignslop - 1) >
1803 longest ||
1804 ((int)(pag->pagf_freeblks + pag->pagf_flcount -
1805 need - args->total) < (int)args->minleft)) {
1806 if (agbp)
1807 xfs_trans_brelse(tp, agbp);
1808 args->agbp = NULL;
1809 return 0;
1810 }
1811 }
1812
1813 /*
1814 * Get the a.g. freespace buffer.
1815 * Can fail if we're not blocking on locks, and it's held.
1816 */
1817 if (agbp == NULL) {
1818 if ((error = xfs_alloc_read_agf(mp, tp, args->agno, flags,
1819 &agbp)))
1820 return error;
1821 if (agbp == NULL) {
1822 ASSERT(flags & XFS_ALLOC_FLAG_TRYLOCK);
1823 ASSERT(!(flags & XFS_ALLOC_FLAG_FREEING));
1824 args->agbp = NULL;
1825 return 0;
1826 }
1827 }
1828 /*
1829 * Figure out how many blocks we should have in the freelist.
1830 */
1831 agf = XFS_BUF_TO_AGF(agbp);
1832 need = XFS_MIN_FREELIST(agf, mp);
1833 /*
1834 * If there isn't enough total or single-extent, reject it.
1835 */
1836 if (!(flags & XFS_ALLOC_FLAG_FREEING)) {
1837 delta = need > be32_to_cpu(agf->agf_flcount) ?
1838 (need - be32_to_cpu(agf->agf_flcount)) : 0;
1839 longest = be32_to_cpu(agf->agf_longest);
1840 longest = (longest > delta) ? (longest - delta) :
1841 (be32_to_cpu(agf->agf_flcount) > 0 || longest > 0);
1842 if ((args->minlen + args->alignment + args->minalignslop - 1) >
1843 longest ||
1844 ((int)(be32_to_cpu(agf->agf_freeblks) +
1845 be32_to_cpu(agf->agf_flcount) - need - args->total) <
1846 (int)args->minleft)) {
1847 xfs_trans_brelse(tp, agbp);
1848 args->agbp = NULL;
1849 return 0;
1850 }
1851 }
1852 /*
1853 * Make the freelist shorter if it's too long.
1854 */
1855 while (be32_to_cpu(agf->agf_flcount) > need) {
1856 xfs_buf_t *bp;
1857
1858 error = xfs_alloc_get_freelist(tp, agbp, &bno, 0);
1859 if (error)
1860 return error;
1861 if ((error = xfs_free_ag_extent(tp, agbp, args->agno, bno, 1, 1)))
1862 return error;
1863 bp = xfs_btree_get_bufs(mp, tp, args->agno, bno, 0);
1864 xfs_trans_binval(tp, bp);
1865 }
1866 /*
1867 * Initialize the args structure.
1868 */
1869 targs.tp = tp;
1870 targs.mp = mp;
1871 targs.agbp = agbp;
1872 targs.agno = args->agno;
1873 targs.mod = targs.minleft = targs.wasdel = targs.userdata =
1874 targs.minalignslop = 0;
1875 targs.alignment = targs.minlen = targs.prod = targs.isfl = 1;
1876 targs.type = XFS_ALLOCTYPE_THIS_AG;
1877 targs.pag = pag;
1878 if ((error = xfs_alloc_read_agfl(mp, tp, targs.agno, &agflbp)))
1879 return error;
1880 /*
1881 * Make the freelist longer if it's too short.
1882 */
1883 while (be32_to_cpu(agf->agf_flcount) < need) {
1884 targs.agbno = 0;
1885 targs.maxlen = need - be32_to_cpu(agf->agf_flcount);
1886 /*
1887 * Allocate as many blocks as possible at once.
1888 */
1889 if ((error = xfs_alloc_ag_vextent(&targs))) {
1890 xfs_trans_brelse(tp, agflbp);
1891 return error;
1892 }
1893 /*
1894 * Stop if we run out. Won't happen if callers are obeying
1895 * the restrictions correctly. Can happen for free calls
1896 * on a completely full ag.
1897 */
1898 if (targs.agbno == NULLAGBLOCK) {
1899 if (flags & XFS_ALLOC_FLAG_FREEING)
1900 break;
1901 xfs_trans_brelse(tp, agflbp);
1902 args->agbp = NULL;
1903 return 0;
1904 }
1905 /*
1906 * Put each allocated block on the list.
1907 */
1908 for (bno = targs.agbno; bno < targs.agbno + targs.len; bno++) {
1909 error = xfs_alloc_put_freelist(tp, agbp,
1910 agflbp, bno, 0);
1911 if (error)
1912 return error;
1913 }
1914 }
1915 xfs_trans_brelse(tp, agflbp);
1916 args->agbp = agbp;
1917 return 0;
1918}
1919
1920/*
1921 * Get a block from the freelist.
1922 * Returns with the buffer for the block gotten.
1923 */
1924int /* error */
1925xfs_alloc_get_freelist(
1926 xfs_trans_t *tp, /* transaction pointer */
1927 xfs_buf_t *agbp, /* buffer containing the agf structure */
1928 xfs_agblock_t *bnop, /* block address retrieved from freelist */
1929 int btreeblk) /* destination is a AGF btree */
1930{
1931 xfs_agf_t *agf; /* a.g. freespace structure */
1932 xfs_agfl_t *agfl; /* a.g. freelist structure */
1933 xfs_buf_t *agflbp;/* buffer for a.g. freelist structure */
1934 xfs_agblock_t bno; /* block number returned */
1935 int error;
1936 int logflags;
1937 xfs_mount_t *mp; /* mount structure */
1938 xfs_perag_t *pag; /* per allocation group data */
1939
1940 agf = XFS_BUF_TO_AGF(agbp);
1941 /*
1942 * Freelist is empty, give up.
1943 */
1944 if (!agf->agf_flcount) {
1945 *bnop = NULLAGBLOCK;
1946 return 0;
1947 }
1948 /*
1949 * Read the array of free blocks.
1950 */
1951 mp = tp->t_mountp;
1952 if ((error = xfs_alloc_read_agfl(mp, tp,
1953 be32_to_cpu(agf->agf_seqno), &agflbp)))
1954 return error;
1955 agfl = XFS_BUF_TO_AGFL(agflbp);
1956 /*
1957 * Get the block number and update the data structures.
1958 */
1959 bno = be32_to_cpu(agfl->agfl_bno[be32_to_cpu(agf->agf_flfirst)]);
1960 be32_add_cpu(&agf->agf_flfirst, 1);
1961 xfs_trans_brelse(tp, agflbp);
1962 if (be32_to_cpu(agf->agf_flfirst) == XFS_AGFL_SIZE(mp))
1963 agf->agf_flfirst = 0;
1964
1965 pag = xfs_perag_get(mp, be32_to_cpu(agf->agf_seqno));
1966 be32_add_cpu(&agf->agf_flcount, -1);
1967 xfs_trans_agflist_delta(tp, -1);
1968 pag->pagf_flcount--;
1969 xfs_perag_put(pag);
1970
1971 logflags = XFS_AGF_FLFIRST | XFS_AGF_FLCOUNT;
1972 if (btreeblk) {
1973 be32_add_cpu(&agf->agf_btreeblks, 1);
1974 pag->pagf_btreeblks++;
1975 logflags |= XFS_AGF_BTREEBLKS;
1976 }
1977
1978 xfs_alloc_log_agf(tp, agbp, logflags);
1979 *bnop = bno;
1980
1981 return 0;
1982}
1983
1984/*
1985 * Log the given fields from the agf structure.
1986 */
1987void
1988xfs_alloc_log_agf(
1989 xfs_trans_t *tp, /* transaction pointer */
1990 xfs_buf_t *bp, /* buffer for a.g. freelist header */
1991 int fields) /* mask of fields to be logged (XFS_AGF_...) */
1992{
1993 int first; /* first byte offset */
1994 int last; /* last byte offset */
1995 static const short offsets[] = {
1996 offsetof(xfs_agf_t, agf_magicnum),
1997 offsetof(xfs_agf_t, agf_versionnum),
1998 offsetof(xfs_agf_t, agf_seqno),
1999 offsetof(xfs_agf_t, agf_length),
2000 offsetof(xfs_agf_t, agf_roots[0]),
2001 offsetof(xfs_agf_t, agf_levels[0]),
2002 offsetof(xfs_agf_t, agf_flfirst),
2003 offsetof(xfs_agf_t, agf_fllast),
2004 offsetof(xfs_agf_t, agf_flcount),
2005 offsetof(xfs_agf_t, agf_freeblks),
2006 offsetof(xfs_agf_t, agf_longest),
2007 offsetof(xfs_agf_t, agf_btreeblks),
2008 sizeof(xfs_agf_t)
2009 };
2010
2011 trace_xfs_agf(tp->t_mountp, XFS_BUF_TO_AGF(bp), fields, _RET_IP_);
2012
2013 xfs_btree_offsets(fields, offsets, XFS_AGF_NUM_BITS, &first, &last);
2014 xfs_trans_log_buf(tp, bp, (uint)first, (uint)last);
2015}
2016
2017/*
2018 * Interface for inode allocation to force the pag data to be initialized.
2019 */
2020int /* error */
2021xfs_alloc_pagf_init(
2022 xfs_mount_t *mp, /* file system mount structure */
2023 xfs_trans_t *tp, /* transaction pointer */
2024 xfs_agnumber_t agno, /* allocation group number */
2025 int flags) /* XFS_ALLOC_FLAGS_... */
2026{
2027 xfs_buf_t *bp;
2028 int error;
2029
2030 if ((error = xfs_alloc_read_agf(mp, tp, agno, flags, &bp)))
2031 return error;
2032 if (bp)
2033 xfs_trans_brelse(tp, bp);
2034 return 0;
2035}
2036
2037/*
2038 * Put the block on the freelist for the allocation group.
2039 */
2040int /* error */
2041xfs_alloc_put_freelist(
2042 xfs_trans_t *tp, /* transaction pointer */
2043 xfs_buf_t *agbp, /* buffer for a.g. freelist header */
2044 xfs_buf_t *agflbp,/* buffer for a.g. free block array */
2045 xfs_agblock_t bno, /* block being freed */
2046 int btreeblk) /* block came from a AGF btree */
2047{
2048 xfs_agf_t *agf; /* a.g. freespace structure */
2049 xfs_agfl_t *agfl; /* a.g. free block array */
2050 __be32 *blockp;/* pointer to array entry */
2051 int error;
2052 int logflags;
2053 xfs_mount_t *mp; /* mount structure */
2054 xfs_perag_t *pag; /* per allocation group data */
2055
2056 agf = XFS_BUF_TO_AGF(agbp);
2057 mp = tp->t_mountp;
2058
2059 if (!agflbp && (error = xfs_alloc_read_agfl(mp, tp,
2060 be32_to_cpu(agf->agf_seqno), &agflbp)))
2061 return error;
2062 agfl = XFS_BUF_TO_AGFL(agflbp);
2063 be32_add_cpu(&agf->agf_fllast, 1);
2064 if (be32_to_cpu(agf->agf_fllast) == XFS_AGFL_SIZE(mp))
2065 agf->agf_fllast = 0;
2066
2067 pag = xfs_perag_get(mp, be32_to_cpu(agf->agf_seqno));
2068 be32_add_cpu(&agf->agf_flcount, 1);
2069 xfs_trans_agflist_delta(tp, 1);
2070 pag->pagf_flcount++;
2071
2072 logflags = XFS_AGF_FLLAST | XFS_AGF_FLCOUNT;
2073 if (btreeblk) {
2074 be32_add_cpu(&agf->agf_btreeblks, -1);
2075 pag->pagf_btreeblks--;
2076 logflags |= XFS_AGF_BTREEBLKS;
2077 }
2078 xfs_perag_put(pag);
2079
2080 xfs_alloc_log_agf(tp, agbp, logflags);
2081
2082 ASSERT(be32_to_cpu(agf->agf_flcount) <= XFS_AGFL_SIZE(mp));
2083 blockp = &agfl->agfl_bno[be32_to_cpu(agf->agf_fllast)];
2084 *blockp = cpu_to_be32(bno);
2085 xfs_alloc_log_agf(tp, agbp, logflags);
2086 xfs_trans_log_buf(tp, agflbp,
2087 (int)((xfs_caddr_t)blockp - (xfs_caddr_t)agfl),
2088 (int)((xfs_caddr_t)blockp - (xfs_caddr_t)agfl +
2089 sizeof(xfs_agblock_t) - 1));
2090 return 0;
2091}
2092
2093/*
2094 * Read in the allocation group header (free/alloc section).
2095 */
2096int /* error */
2097xfs_read_agf(
2098 struct xfs_mount *mp, /* mount point structure */
2099 struct xfs_trans *tp, /* transaction pointer */
2100 xfs_agnumber_t agno, /* allocation group number */
2101 int flags, /* XFS_BUF_ */
2102 struct xfs_buf **bpp) /* buffer for the ag freelist header */
2103{
2104 struct xfs_agf *agf; /* ag freelist header */
2105 int agf_ok; /* set if agf is consistent */
2106 int error;
2107
2108 ASSERT(agno != NULLAGNUMBER);
2109 error = xfs_trans_read_buf(
2110 mp, tp, mp->m_ddev_targp,
2111 XFS_AG_DADDR(mp, agno, XFS_AGF_DADDR(mp)),
2112 XFS_FSS_TO_BB(mp, 1), flags, bpp);
2113 if (error)
2114 return error;
2115 if (!*bpp)
2116 return 0;
2117
2118 ASSERT(!(*bpp)->b_error);
2119 agf = XFS_BUF_TO_AGF(*bpp);
2120
2121 /*
2122 * Validate the magic number of the agf block.
2123 */
2124 agf_ok =
2125 agf->agf_magicnum == cpu_to_be32(XFS_AGF_MAGIC) &&
2126 XFS_AGF_GOOD_VERSION(be32_to_cpu(agf->agf_versionnum)) &&
2127 be32_to_cpu(agf->agf_freeblks) <= be32_to_cpu(agf->agf_length) &&
2128 be32_to_cpu(agf->agf_flfirst) < XFS_AGFL_SIZE(mp) &&
2129 be32_to_cpu(agf->agf_fllast) < XFS_AGFL_SIZE(mp) &&
2130 be32_to_cpu(agf->agf_flcount) <= XFS_AGFL_SIZE(mp) &&
2131 be32_to_cpu(agf->agf_seqno) == agno;
2132 if (xfs_sb_version_haslazysbcount(&mp->m_sb))
2133 agf_ok = agf_ok && be32_to_cpu(agf->agf_btreeblks) <=
2134 be32_to_cpu(agf->agf_length);
2135 if (unlikely(XFS_TEST_ERROR(!agf_ok, mp, XFS_ERRTAG_ALLOC_READ_AGF,
2136 XFS_RANDOM_ALLOC_READ_AGF))) {
2137 XFS_CORRUPTION_ERROR("xfs_alloc_read_agf",
2138 XFS_ERRLEVEL_LOW, mp, agf);
2139 xfs_trans_brelse(tp, *bpp);
2140 return XFS_ERROR(EFSCORRUPTED);
2141 }
2142 XFS_BUF_SET_VTYPE_REF(*bpp, B_FS_AGF, XFS_AGF_REF);
2143 return 0;
2144}
2145
2146/*
2147 * Read in the allocation group header (free/alloc section).
2148 */
2149int /* error */
2150xfs_alloc_read_agf(
2151 struct xfs_mount *mp, /* mount point structure */
2152 struct xfs_trans *tp, /* transaction pointer */
2153 xfs_agnumber_t agno, /* allocation group number */
2154 int flags, /* XFS_ALLOC_FLAG_... */
2155 struct xfs_buf **bpp) /* buffer for the ag freelist header */
2156{
2157 struct xfs_agf *agf; /* ag freelist header */
2158 struct xfs_perag *pag; /* per allocation group data */
2159 int error;
2160
2161 ASSERT(agno != NULLAGNUMBER);
2162
2163 error = xfs_read_agf(mp, tp, agno,
2164 (flags & XFS_ALLOC_FLAG_TRYLOCK) ? XBF_TRYLOCK : 0,
2165 bpp);
2166 if (error)
2167 return error;
2168 if (!*bpp)
2169 return 0;
2170 ASSERT(!(*bpp)->b_error);
2171
2172 agf = XFS_BUF_TO_AGF(*bpp);
2173 pag = xfs_perag_get(mp, agno);
2174 if (!pag->pagf_init) {
2175 pag->pagf_freeblks = be32_to_cpu(agf->agf_freeblks);
2176 pag->pagf_btreeblks = be32_to_cpu(agf->agf_btreeblks);
2177 pag->pagf_flcount = be32_to_cpu(agf->agf_flcount);
2178 pag->pagf_longest = be32_to_cpu(agf->agf_longest);
2179 pag->pagf_levels[XFS_BTNUM_BNOi] =
2180 be32_to_cpu(agf->agf_levels[XFS_BTNUM_BNOi]);
2181 pag->pagf_levels[XFS_BTNUM_CNTi] =
2182 be32_to_cpu(agf->agf_levels[XFS_BTNUM_CNTi]);
2183 spin_lock_init(&pag->pagb_lock);
2184 pag->pagb_count = 0;
2185 pag->pagb_tree = RB_ROOT;
2186 pag->pagf_init = 1;
2187 }
2188#ifdef DEBUG
2189 else if (!XFS_FORCED_SHUTDOWN(mp)) {
2190 ASSERT(pag->pagf_freeblks == be32_to_cpu(agf->agf_freeblks));
2191 ASSERT(pag->pagf_btreeblks == be32_to_cpu(agf->agf_btreeblks));
2192 ASSERT(pag->pagf_flcount == be32_to_cpu(agf->agf_flcount));
2193 ASSERT(pag->pagf_longest == be32_to_cpu(agf->agf_longest));
2194 ASSERT(pag->pagf_levels[XFS_BTNUM_BNOi] ==
2195 be32_to_cpu(agf->agf_levels[XFS_BTNUM_BNOi]));
2196 ASSERT(pag->pagf_levels[XFS_BTNUM_CNTi] ==
2197 be32_to_cpu(agf->agf_levels[XFS_BTNUM_CNTi]));
2198 }
2199#endif
2200 xfs_perag_put(pag);
2201 return 0;
2202}
2203
2204/*
2205 * Allocate an extent (variable-size).
2206 * Depending on the allocation type, we either look in a single allocation
2207 * group or loop over the allocation groups to find the result.
2208 */
2209int /* error */
2210xfs_alloc_vextent(
2211 xfs_alloc_arg_t *args) /* allocation argument structure */
2212{
2213 xfs_agblock_t agsize; /* allocation group size */
2214 int error;
2215 int flags; /* XFS_ALLOC_FLAG_... locking flags */
2216 xfs_extlen_t minleft;/* minimum left value, temp copy */
2217 xfs_mount_t *mp; /* mount structure pointer */
2218 xfs_agnumber_t sagno; /* starting allocation group number */
2219 xfs_alloctype_t type; /* input allocation type */
2220 int bump_rotor = 0;
2221 int no_min = 0;
2222 xfs_agnumber_t rotorstep = xfs_rotorstep; /* inode32 agf stepper */
2223
2224 mp = args->mp;
2225 type = args->otype = args->type;
2226 args->agbno = NULLAGBLOCK;
2227 /*
2228 * Just fix this up, for the case where the last a.g. is shorter
2229 * (or there's only one a.g.) and the caller couldn't easily figure
2230 * that out (xfs_bmap_alloc).
2231 */
2232 agsize = mp->m_sb.sb_agblocks;
2233 if (args->maxlen > agsize)
2234 args->maxlen = agsize;
2235 if (args->alignment == 0)
2236 args->alignment = 1;
2237 ASSERT(XFS_FSB_TO_AGNO(mp, args->fsbno) < mp->m_sb.sb_agcount);
2238 ASSERT(XFS_FSB_TO_AGBNO(mp, args->fsbno) < agsize);
2239 ASSERT(args->minlen <= args->maxlen);
2240 ASSERT(args->minlen <= agsize);
2241 ASSERT(args->mod < args->prod);
2242 if (XFS_FSB_TO_AGNO(mp, args->fsbno) >= mp->m_sb.sb_agcount ||
2243 XFS_FSB_TO_AGBNO(mp, args->fsbno) >= agsize ||
2244 args->minlen > args->maxlen || args->minlen > agsize ||
2245 args->mod >= args->prod) {
2246 args->fsbno = NULLFSBLOCK;
2247 trace_xfs_alloc_vextent_badargs(args);
2248 return 0;
2249 }
2250 minleft = args->minleft;
2251
2252 switch (type) {
2253 case XFS_ALLOCTYPE_THIS_AG:
2254 case XFS_ALLOCTYPE_NEAR_BNO:
2255 case XFS_ALLOCTYPE_THIS_BNO:
2256 /*
2257 * These three force us into a single a.g.
2258 */
2259 args->agno = XFS_FSB_TO_AGNO(mp, args->fsbno);
2260 args->pag = xfs_perag_get(mp, args->agno);
2261 args->minleft = 0;
2262 error = xfs_alloc_fix_freelist(args, 0);
2263 args->minleft = minleft;
2264 if (error) {
2265 trace_xfs_alloc_vextent_nofix(args);
2266 goto error0;
2267 }
2268 if (!args->agbp) {
2269 trace_xfs_alloc_vextent_noagbp(args);
2270 break;
2271 }
2272 args->agbno = XFS_FSB_TO_AGBNO(mp, args->fsbno);
2273 if ((error = xfs_alloc_ag_vextent(args)))
2274 goto error0;
2275 break;
2276 case XFS_ALLOCTYPE_START_BNO:
2277 /*
2278 * Try near allocation first, then anywhere-in-ag after
2279 * the first a.g. fails.
2280 */
2281 if ((args->userdata == XFS_ALLOC_INITIAL_USER_DATA) &&
2282 (mp->m_flags & XFS_MOUNT_32BITINODES)) {
2283 args->fsbno = XFS_AGB_TO_FSB(mp,
2284 ((mp->m_agfrotor / rotorstep) %
2285 mp->m_sb.sb_agcount), 0);
2286 bump_rotor = 1;
2287 }
2288 args->agbno = XFS_FSB_TO_AGBNO(mp, args->fsbno);
2289 args->type = XFS_ALLOCTYPE_NEAR_BNO;
2290 /* FALLTHROUGH */
2291 case XFS_ALLOCTYPE_ANY_AG:
2292 case XFS_ALLOCTYPE_START_AG:
2293 case XFS_ALLOCTYPE_FIRST_AG:
2294 /*
2295 * Rotate through the allocation groups looking for a winner.
2296 */
2297 if (type == XFS_ALLOCTYPE_ANY_AG) {
2298 /*
2299 * Start with the last place we left off.
2300 */
2301 args->agno = sagno = (mp->m_agfrotor / rotorstep) %
2302 mp->m_sb.sb_agcount;
2303 args->type = XFS_ALLOCTYPE_THIS_AG;
2304 flags = XFS_ALLOC_FLAG_TRYLOCK;
2305 } else if (type == XFS_ALLOCTYPE_FIRST_AG) {
2306 /*
2307 * Start with allocation group given by bno.
2308 */
2309 args->agno = XFS_FSB_TO_AGNO(mp, args->fsbno);
2310 args->type = XFS_ALLOCTYPE_THIS_AG;
2311 sagno = 0;
2312 flags = 0;
2313 } else {
2314 if (type == XFS_ALLOCTYPE_START_AG)
2315 args->type = XFS_ALLOCTYPE_THIS_AG;
2316 /*
2317 * Start with the given allocation group.
2318 */
2319 args->agno = sagno = XFS_FSB_TO_AGNO(mp, args->fsbno);
2320 flags = XFS_ALLOC_FLAG_TRYLOCK;
2321 }
2322 /*
2323 * Loop over allocation groups twice; first time with
2324 * trylock set, second time without.
2325 */
2326 for (;;) {
2327 args->pag = xfs_perag_get(mp, args->agno);
2328 if (no_min) args->minleft = 0;
2329 error = xfs_alloc_fix_freelist(args, flags);
2330 args->minleft = minleft;
2331 if (error) {
2332 trace_xfs_alloc_vextent_nofix(args);
2333 goto error0;
2334 }
2335 /*
2336 * If we get a buffer back then the allocation will fly.
2337 */
2338 if (args->agbp) {
2339 if ((error = xfs_alloc_ag_vextent(args)))
2340 goto error0;
2341 break;
2342 }
2343
2344 trace_xfs_alloc_vextent_loopfailed(args);
2345
2346 /*
2347 * Didn't work, figure out the next iteration.
2348 */
2349 if (args->agno == sagno &&
2350 type == XFS_ALLOCTYPE_START_BNO)
2351 args->type = XFS_ALLOCTYPE_THIS_AG;
2352 /*
2353 * For the first allocation, we can try any AG to get
2354 * space. However, if we already have allocated a
2355 * block, we don't want to try AGs whose number is below
2356 * sagno. Otherwise, we may end up with out-of-order
2357 * locking of AGF, which might cause deadlock.
2358 */
2359 if (++(args->agno) == mp->m_sb.sb_agcount) {
2360 if (args->firstblock != NULLFSBLOCK)
2361 args->agno = sagno;
2362 else
2363 args->agno = 0;
2364 }
2365 /*
2366 * Reached the starting a.g., must either be done
2367 * or switch to non-trylock mode.
2368 */
2369 if (args->agno == sagno) {
2370 if (no_min == 1) {
2371 args->agbno = NULLAGBLOCK;
2372 trace_xfs_alloc_vextent_allfailed(args);
2373 break;
2374 }
2375 if (flags == 0) {
2376 no_min = 1;
2377 } else {
2378 flags = 0;
2379 if (type == XFS_ALLOCTYPE_START_BNO) {
2380 args->agbno = XFS_FSB_TO_AGBNO(mp,
2381 args->fsbno);
2382 args->type = XFS_ALLOCTYPE_NEAR_BNO;
2383 }
2384 }
2385 }
2386 xfs_perag_put(args->pag);
2387 }
2388 if (bump_rotor || (type == XFS_ALLOCTYPE_ANY_AG)) {
2389 if (args->agno == sagno)
2390 mp->m_agfrotor = (mp->m_agfrotor + 1) %
2391 (mp->m_sb.sb_agcount * rotorstep);
2392 else
2393 mp->m_agfrotor = (args->agno * rotorstep + 1) %
2394 (mp->m_sb.sb_agcount * rotorstep);
2395 }
2396 break;
2397 default:
2398 ASSERT(0);
2399 /* NOTREACHED */
2400 }
2401 if (args->agbno == NULLAGBLOCK)
2402 args->fsbno = NULLFSBLOCK;
2403 else {
2404 args->fsbno = XFS_AGB_TO_FSB(mp, args->agno, args->agbno);
2405#ifdef DEBUG
2406 ASSERT(args->len >= args->minlen);
2407 ASSERT(args->len <= args->maxlen);
2408 ASSERT(args->agbno % args->alignment == 0);
2409 XFS_AG_CHECK_DADDR(mp, XFS_FSB_TO_DADDR(mp, args->fsbno),
2410 args->len);
2411#endif
2412 }
2413 xfs_perag_put(args->pag);
2414 return 0;
2415error0:
2416 xfs_perag_put(args->pag);
2417 return error;
2418}
2419
2420/*
2421 * Free an extent.
2422 * Just break up the extent address and hand off to xfs_free_ag_extent
2423 * after fixing up the freelist.
2424 */
2425int /* error */
2426xfs_free_extent(
2427 xfs_trans_t *tp, /* transaction pointer */
2428 xfs_fsblock_t bno, /* starting block number of extent */
2429 xfs_extlen_t len) /* length of extent */
2430{
2431 xfs_alloc_arg_t args;
2432 int error;
2433
2434 ASSERT(len != 0);
2435 memset(&args, 0, sizeof(xfs_alloc_arg_t));
2436 args.tp = tp;
2437 args.mp = tp->t_mountp;
2438
2439 /*
2440 * validate that the block number is legal - the enables us to detect
2441 * and handle a silent filesystem corruption rather than crashing.
2442 */
2443 args.agno = XFS_FSB_TO_AGNO(args.mp, bno);
2444 if (args.agno >= args.mp->m_sb.sb_agcount)
2445 return EFSCORRUPTED;
2446
2447 args.agbno = XFS_FSB_TO_AGBNO(args.mp, bno);
2448 if (args.agbno >= args.mp->m_sb.sb_agblocks)
2449 return EFSCORRUPTED;
2450
2451 args.pag = xfs_perag_get(args.mp, args.agno);
2452 ASSERT(args.pag);
2453
2454 error = xfs_alloc_fix_freelist(&args, XFS_ALLOC_FLAG_FREEING);
2455 if (error)
2456 goto error0;
2457
2458 /* validate the extent size is legal now we have the agf locked */
2459 if (args.agbno + len >
2460 be32_to_cpu(XFS_BUF_TO_AGF(args.agbp)->agf_length)) {
2461 error = EFSCORRUPTED;
2462 goto error0;
2463 }
2464
2465 error = xfs_free_ag_extent(tp, args.agbp, args.agno, args.agbno, len, 0);
2466 if (!error)
2467 xfs_alloc_busy_insert(tp, args.agno, args.agbno, len, 0);
2468error0:
2469 xfs_perag_put(args.pag);
2470 return error;
2471}
2472
2473void
2474xfs_alloc_busy_insert(
2475 struct xfs_trans *tp,
2476 xfs_agnumber_t agno,
2477 xfs_agblock_t bno,
2478 xfs_extlen_t len,
2479 unsigned int flags)
2480{
2481 struct xfs_busy_extent *new;
2482 struct xfs_busy_extent *busyp;
2483 struct xfs_perag *pag;
2484 struct rb_node **rbp;
2485 struct rb_node *parent = NULL;
2486
2487 new = kmem_zalloc(sizeof(struct xfs_busy_extent), KM_MAYFAIL);
2488 if (!new) {
2489 /*
2490 * No Memory! Since it is now not possible to track the free
2491 * block, make this a synchronous transaction to insure that
2492 * the block is not reused before this transaction commits.
2493 */
2494 trace_xfs_alloc_busy_enomem(tp->t_mountp, agno, bno, len);
2495 xfs_trans_set_sync(tp);
2496 return;
2497 }
2498
2499 new->agno = agno;
2500 new->bno = bno;
2501 new->length = len;
2502 INIT_LIST_HEAD(&new->list);
2503 new->flags = flags;
2504
2505 /* trace before insert to be able to see failed inserts */
2506 trace_xfs_alloc_busy(tp->t_mountp, agno, bno, len);
2507
2508 pag = xfs_perag_get(tp->t_mountp, new->agno);
2509 spin_lock(&pag->pagb_lock);
2510 rbp = &pag->pagb_tree.rb_node;
2511 while (*rbp) {
2512 parent = *rbp;
2513 busyp = rb_entry(parent, struct xfs_busy_extent, rb_node);
2514
2515 if (new->bno < busyp->bno) {
2516 rbp = &(*rbp)->rb_left;
2517 ASSERT(new->bno + new->length <= busyp->bno);
2518 } else if (new->bno > busyp->bno) {
2519 rbp = &(*rbp)->rb_right;
2520 ASSERT(bno >= busyp->bno + busyp->length);
2521 } else {
2522 ASSERT(0);
2523 }
2524 }
2525
2526 rb_link_node(&new->rb_node, parent, rbp);
2527 rb_insert_color(&new->rb_node, &pag->pagb_tree);
2528
2529 list_add(&new->list, &tp->t_busy);
2530 spin_unlock(&pag->pagb_lock);
2531 xfs_perag_put(pag);
2532}
2533
2534/*
2535 * Search for a busy extent within the range of the extent we are about to
2536 * allocate. You need to be holding the busy extent tree lock when calling
2537 * xfs_alloc_busy_search(). This function returns 0 for no overlapping busy
2538 * extent, -1 for an overlapping but not exact busy extent, and 1 for an exact
2539 * match. This is done so that a non-zero return indicates an overlap that
2540 * will require a synchronous transaction, but it can still be
2541 * used to distinguish between a partial or exact match.
2542 */
2543int
2544xfs_alloc_busy_search(
2545 struct xfs_mount *mp,
2546 xfs_agnumber_t agno,
2547 xfs_agblock_t bno,
2548 xfs_extlen_t len)
2549{
2550 struct xfs_perag *pag;
2551 struct rb_node *rbp;
2552 struct xfs_busy_extent *busyp;
2553 int match = 0;
2554
2555 pag = xfs_perag_get(mp, agno);
2556 spin_lock(&pag->pagb_lock);
2557
2558 rbp = pag->pagb_tree.rb_node;
2559
2560 /* find closest start bno overlap */
2561 while (rbp) {
2562 busyp = rb_entry(rbp, struct xfs_busy_extent, rb_node);
2563 if (bno < busyp->bno) {
2564 /* may overlap, but exact start block is lower */
2565 if (bno + len > busyp->bno)
2566 match = -1;
2567 rbp = rbp->rb_left;
2568 } else if (bno > busyp->bno) {
2569 /* may overlap, but exact start block is higher */
2570 if (bno < busyp->bno + busyp->length)
2571 match = -1;
2572 rbp = rbp->rb_right;
2573 } else {
2574 /* bno matches busyp, length determines exact match */
2575 match = (busyp->length == len) ? 1 : -1;
2576 break;
2577 }
2578 }
2579 spin_unlock(&pag->pagb_lock);
2580 xfs_perag_put(pag);
2581 return match;
2582}
2583
2584/*
2585 * The found free extent [fbno, fend] overlaps part or all of the given busy
2586 * extent. If the overlap covers the beginning, the end, or all of the busy
2587 * extent, the overlapping portion can be made unbusy and used for the
2588 * allocation. We can't split a busy extent because we can't modify a
2589 * transaction/CIL context busy list, but we can update an entries block
2590 * number or length.
2591 *
2592 * Returns true if the extent can safely be reused, or false if the search
2593 * needs to be restarted.
2594 */
2595STATIC bool
2596xfs_alloc_busy_update_extent(
2597 struct xfs_mount *mp,
2598 struct xfs_perag *pag,
2599 struct xfs_busy_extent *busyp,
2600 xfs_agblock_t fbno,
2601 xfs_extlen_t flen,
2602 bool userdata)
2603{
2604 xfs_agblock_t fend = fbno + flen;
2605 xfs_agblock_t bbno = busyp->bno;
2606 xfs_agblock_t bend = bbno + busyp->length;
2607
2608 /*
2609 * This extent is currently being discarded. Give the thread
2610 * performing the discard a chance to mark the extent unbusy
2611 * and retry.
2612 */
2613 if (busyp->flags & XFS_ALLOC_BUSY_DISCARDED) {
2614 spin_unlock(&pag->pagb_lock);
2615 delay(1);
2616 spin_lock(&pag->pagb_lock);
2617 return false;
2618 }
2619
2620 /*
2621 * If there is a busy extent overlapping a user allocation, we have
2622 * no choice but to force the log and retry the search.
2623 *
2624 * Fortunately this does not happen during normal operation, but
2625 * only if the filesystem is very low on space and has to dip into
2626 * the AGFL for normal allocations.
2627 */
2628 if (userdata)
2629 goto out_force_log;
2630
2631 if (bbno < fbno && bend > fend) {
2632 /*
2633 * Case 1:
2634 * bbno bend
2635 * +BBBBBBBBBBBBBBBBB+
2636 * +---------+
2637 * fbno fend
2638 */
2639
2640 /*
2641 * We would have to split the busy extent to be able to track
2642 * it correct, which we cannot do because we would have to
2643 * modify the list of busy extents attached to the transaction
2644 * or CIL context, which is immutable.
2645 *
2646 * Force out the log to clear the busy extent and retry the
2647 * search.
2648 */
2649 goto out_force_log;
2650 } else if (bbno >= fbno && bend <= fend) {
2651 /*
2652 * Case 2:
2653 * bbno bend
2654 * +BBBBBBBBBBBBBBBBB+
2655 * +-----------------+
2656 * fbno fend
2657 *
2658 * Case 3:
2659 * bbno bend
2660 * +BBBBBBBBBBBBBBBBB+
2661 * +--------------------------+
2662 * fbno fend
2663 *
2664 * Case 4:
2665 * bbno bend
2666 * +BBBBBBBBBBBBBBBBB+
2667 * +--------------------------+
2668 * fbno fend
2669 *
2670 * Case 5:
2671 * bbno bend
2672 * +BBBBBBBBBBBBBBBBB+
2673 * +-----------------------------------+
2674 * fbno fend
2675 *
2676 */
2677
2678 /*
2679 * The busy extent is fully covered by the extent we are
2680 * allocating, and can simply be removed from the rbtree.
2681 * However we cannot remove it from the immutable list
2682 * tracking busy extents in the transaction or CIL context,
2683 * so set the length to zero to mark it invalid.
2684 *
2685 * We also need to restart the busy extent search from the
2686 * tree root, because erasing the node can rearrange the
2687 * tree topology.
2688 */
2689 rb_erase(&busyp->rb_node, &pag->pagb_tree);
2690 busyp->length = 0;
2691 return false;
2692 } else if (fend < bend) {
2693 /*
2694 * Case 6:
2695 * bbno bend
2696 * +BBBBBBBBBBBBBBBBB+
2697 * +---------+
2698 * fbno fend
2699 *
2700 * Case 7:
2701 * bbno bend
2702 * +BBBBBBBBBBBBBBBBB+
2703 * +------------------+
2704 * fbno fend
2705 *
2706 */
2707 busyp->bno = fend;
2708 } else if (bbno < fbno) {
2709 /*
2710 * Case 8:
2711 * bbno bend
2712 * +BBBBBBBBBBBBBBBBB+
2713 * +-------------+
2714 * fbno fend
2715 *
2716 * Case 9:
2717 * bbno bend
2718 * +BBBBBBBBBBBBBBBBB+
2719 * +----------------------+
2720 * fbno fend
2721 */
2722 busyp->length = fbno - busyp->bno;
2723 } else {
2724 ASSERT(0);
2725 }
2726
2727 trace_xfs_alloc_busy_reuse(mp, pag->pag_agno, fbno, flen);
2728 return true;
2729
2730out_force_log:
2731 spin_unlock(&pag->pagb_lock);
2732 xfs_log_force(mp, XFS_LOG_SYNC);
2733 trace_xfs_alloc_busy_force(mp, pag->pag_agno, fbno, flen);
2734 spin_lock(&pag->pagb_lock);
2735 return false;
2736}
2737
2738
2739/*
2740 * For a given extent [fbno, flen], make sure we can reuse it safely.
2741 */
2742void
2743xfs_alloc_busy_reuse(
2744 struct xfs_mount *mp,
2745 xfs_agnumber_t agno,
2746 xfs_agblock_t fbno,
2747 xfs_extlen_t flen,
2748 bool userdata)
2749{
2750 struct xfs_perag *pag;
2751 struct rb_node *rbp;
2752
2753 ASSERT(flen > 0);
2754
2755 pag = xfs_perag_get(mp, agno);
2756 spin_lock(&pag->pagb_lock);
2757restart:
2758 rbp = pag->pagb_tree.rb_node;
2759 while (rbp) {
2760 struct xfs_busy_extent *busyp =
2761 rb_entry(rbp, struct xfs_busy_extent, rb_node);
2762 xfs_agblock_t bbno = busyp->bno;
2763 xfs_agblock_t bend = bbno + busyp->length;
2764
2765 if (fbno + flen <= bbno) {
2766 rbp = rbp->rb_left;
2767 continue;
2768 } else if (fbno >= bend) {
2769 rbp = rbp->rb_right;
2770 continue;
2771 }
2772
2773 if (!xfs_alloc_busy_update_extent(mp, pag, busyp, fbno, flen,
2774 userdata))
2775 goto restart;
2776 }
2777 spin_unlock(&pag->pagb_lock);
2778 xfs_perag_put(pag);
2779}
2780
2781/*
2782 * For a given extent [fbno, flen], search the busy extent list to find a
2783 * subset of the extent that is not busy. If *rlen is smaller than
2784 * args->minlen no suitable extent could be found, and the higher level
2785 * code needs to force out the log and retry the allocation.
2786 */
2787STATIC void
2788xfs_alloc_busy_trim(
2789 struct xfs_alloc_arg *args,
2790 xfs_agblock_t bno,
2791 xfs_extlen_t len,
2792 xfs_agblock_t *rbno,
2793 xfs_extlen_t *rlen)
2794{
2795 xfs_agblock_t fbno;
2796 xfs_extlen_t flen;
2797 struct rb_node *rbp;
2798
2799 ASSERT(len > 0);
2800
2801 spin_lock(&args->pag->pagb_lock);
2802restart:
2803 fbno = bno;
2804 flen = len;
2805 rbp = args->pag->pagb_tree.rb_node;
2806 while (rbp && flen >= args->minlen) {
2807 struct xfs_busy_extent *busyp =
2808 rb_entry(rbp, struct xfs_busy_extent, rb_node);
2809 xfs_agblock_t fend = fbno + flen;
2810 xfs_agblock_t bbno = busyp->bno;
2811 xfs_agblock_t bend = bbno + busyp->length;
2812
2813 if (fend <= bbno) {
2814 rbp = rbp->rb_left;
2815 continue;
2816 } else if (fbno >= bend) {
2817 rbp = rbp->rb_right;
2818 continue;
2819 }
2820
2821 /*
2822 * If this is a metadata allocation, try to reuse the busy
2823 * extent instead of trimming the allocation.
2824 */
2825 if (!args->userdata &&
2826 !(busyp->flags & XFS_ALLOC_BUSY_DISCARDED)) {
2827 if (!xfs_alloc_busy_update_extent(args->mp, args->pag,
2828 busyp, fbno, flen,
2829 false))
2830 goto restart;
2831 continue;
2832 }
2833
2834 if (bbno <= fbno) {
2835 /* start overlap */
2836
2837 /*
2838 * Case 1:
2839 * bbno bend
2840 * +BBBBBBBBBBBBBBBBB+
2841 * +---------+
2842 * fbno fend
2843 *
2844 * Case 2:
2845 * bbno bend
2846 * +BBBBBBBBBBBBBBBBB+
2847 * +-------------+
2848 * fbno fend
2849 *
2850 * Case 3:
2851 * bbno bend
2852 * +BBBBBBBBBBBBBBBBB+
2853 * +-------------+
2854 * fbno fend
2855 *
2856 * Case 4:
2857 * bbno bend
2858 * +BBBBBBBBBBBBBBBBB+
2859 * +-----------------+
2860 * fbno fend
2861 *
2862 * No unbusy region in extent, return failure.
2863 */
2864 if (fend <= bend)
2865 goto fail;
2866
2867 /*
2868 * Case 5:
2869 * bbno bend
2870 * +BBBBBBBBBBBBBBBBB+
2871 * +----------------------+
2872 * fbno fend
2873 *
2874 * Case 6:
2875 * bbno bend
2876 * +BBBBBBBBBBBBBBBBB+
2877 * +--------------------------+
2878 * fbno fend
2879 *
2880 * Needs to be trimmed to:
2881 * +-------+
2882 * fbno fend
2883 */
2884 fbno = bend;
2885 } else if (bend >= fend) {
2886 /* end overlap */
2887
2888 /*
2889 * Case 7:
2890 * bbno bend
2891 * +BBBBBBBBBBBBBBBBB+
2892 * +------------------+
2893 * fbno fend
2894 *
2895 * Case 8:
2896 * bbno bend
2897 * +BBBBBBBBBBBBBBBBB+
2898 * +--------------------------+
2899 * fbno fend
2900 *
2901 * Needs to be trimmed to:
2902 * +-------+
2903 * fbno fend
2904 */
2905 fend = bbno;
2906 } else {
2907 /* middle overlap */
2908
2909 /*
2910 * Case 9:
2911 * bbno bend
2912 * +BBBBBBBBBBBBBBBBB+
2913 * +-----------------------------------+
2914 * fbno fend
2915 *
2916 * Can be trimmed to:
2917 * +-------+ OR +-------+
2918 * fbno fend fbno fend
2919 *
2920 * Backward allocation leads to significant
2921 * fragmentation of directories, which degrades
2922 * directory performance, therefore we always want to
2923 * choose the option that produces forward allocation
2924 * patterns.
2925 * Preferring the lower bno extent will make the next
2926 * request use "fend" as the start of the next
2927 * allocation; if the segment is no longer busy at
2928 * that point, we'll get a contiguous allocation, but
2929 * even if it is still busy, we will get a forward
2930 * allocation.
2931 * We try to avoid choosing the segment at "bend",
2932 * because that can lead to the next allocation
2933 * taking the segment at "fbno", which would be a
2934 * backward allocation. We only use the segment at
2935 * "fbno" if it is much larger than the current
2936 * requested size, because in that case there's a
2937 * good chance subsequent allocations will be
2938 * contiguous.
2939 */
2940 if (bbno - fbno >= args->maxlen) {
2941 /* left candidate fits perfect */
2942 fend = bbno;
2943 } else if (fend - bend >= args->maxlen * 4) {
2944 /* right candidate has enough free space */
2945 fbno = bend;
2946 } else if (bbno - fbno >= args->minlen) {
2947 /* left candidate fits minimum requirement */
2948 fend = bbno;
2949 } else {
2950 goto fail;
2951 }
2952 }
2953
2954 flen = fend - fbno;
2955 }
2956 spin_unlock(&args->pag->pagb_lock);
2957
2958 if (fbno != bno || flen != len) {
2959 trace_xfs_alloc_busy_trim(args->mp, args->agno, bno, len,
2960 fbno, flen);
2961 }
2962 *rbno = fbno;
2963 *rlen = flen;
2964 return;
2965fail:
2966 /*
2967 * Return a zero extent length as failure indications. All callers
2968 * re-check if the trimmed extent satisfies the minlen requirement.
2969 */
2970 spin_unlock(&args->pag->pagb_lock);
2971 trace_xfs_alloc_busy_trim(args->mp, args->agno, bno, len, fbno, 0);
2972 *rbno = fbno;
2973 *rlen = 0;
2974}
2975
2976static void
2977xfs_alloc_busy_clear_one(
2978 struct xfs_mount *mp,
2979 struct xfs_perag *pag,
2980 struct xfs_busy_extent *busyp)
2981{
2982 if (busyp->length) {
2983 trace_xfs_alloc_busy_clear(mp, busyp->agno, busyp->bno,
2984 busyp->length);
2985 rb_erase(&busyp->rb_node, &pag->pagb_tree);
2986 }
2987
2988 list_del_init(&busyp->list);
2989 kmem_free(busyp);
2990}
2991
2992/*
2993 * Remove all extents on the passed in list from the busy extents tree.
2994 * If do_discard is set skip extents that need to be discarded, and mark
2995 * these as undergoing a discard operation instead.
2996 */
2997void
2998xfs_alloc_busy_clear(
2999 struct xfs_mount *mp,
3000 struct list_head *list,
3001 bool do_discard)
3002{
3003 struct xfs_busy_extent *busyp, *n;
3004 struct xfs_perag *pag = NULL;
3005 xfs_agnumber_t agno = NULLAGNUMBER;
3006
3007 list_for_each_entry_safe(busyp, n, list, list) {
3008 if (busyp->agno != agno) {
3009 if (pag) {
3010 spin_unlock(&pag->pagb_lock);
3011 xfs_perag_put(pag);
3012 }
3013 pag = xfs_perag_get(mp, busyp->agno);
3014 spin_lock(&pag->pagb_lock);
3015 agno = busyp->agno;
3016 }
3017
3018 if (do_discard && busyp->length &&
3019 !(busyp->flags & XFS_ALLOC_BUSY_SKIP_DISCARD))
3020 busyp->flags = XFS_ALLOC_BUSY_DISCARDED;
3021 else
3022 xfs_alloc_busy_clear_one(mp, pag, busyp);
3023 }
3024
3025 if (pag) {
3026 spin_unlock(&pag->pagb_lock);
3027 xfs_perag_put(pag);
3028 }
3029}
3030
3031/*
3032 * Callback for list_sort to sort busy extents by the AG they reside in.
3033 */
3034int
3035xfs_busy_extent_ag_cmp(
3036 void *priv,
3037 struct list_head *a,
3038 struct list_head *b)
3039{
3040 return container_of(a, struct xfs_busy_extent, list)->agno -
3041 container_of(b, struct xfs_busy_extent, list)->agno;
3042}
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_format.h"
21#include "xfs_log_format.h"
22#include "xfs_shared.h"
23#include "xfs_trans_resv.h"
24#include "xfs_bit.h"
25#include "xfs_sb.h"
26#include "xfs_ag.h"
27#include "xfs_mount.h"
28#include "xfs_inode.h"
29#include "xfs_btree.h"
30#include "xfs_alloc_btree.h"
31#include "xfs_alloc.h"
32#include "xfs_extent_busy.h"
33#include "xfs_error.h"
34#include "xfs_cksum.h"
35#include "xfs_trace.h"
36#include "xfs_trans.h"
37#include "xfs_buf_item.h"
38#include "xfs_log.h"
39
40struct 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
47STATIC int xfs_alloc_ag_vextent_exact(xfs_alloc_arg_t *);
48STATIC int xfs_alloc_ag_vextent_near(xfs_alloc_arg_t *);
49STATIC int xfs_alloc_ag_vextent_size(xfs_alloc_arg_t *);
50STATIC 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 */
56STATIC int /* error */
57xfs_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 */
72int /* error */
73xfs_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 */
88int /* error */
89xfs_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 */
105STATIC int /* error */
106xfs_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 */
121int /* error */
122xfs_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 */
143STATIC void
144xfs_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 */
173STATIC xfs_extlen_t /* difference value (absolute) */
174xfs_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 char userdata, /* are we allocating data? */
179 xfs_agblock_t freebno, /* freespace's starting block */
180 xfs_extlen_t freelen, /* freespace's length */
181 xfs_agblock_t *newbnop) /* result: best start block from free */
182{
183 xfs_agblock_t freeend; /* end of freespace extent */
184 xfs_agblock_t newbno1; /* return block number */
185 xfs_agblock_t newbno2; /* other new block number */
186 xfs_extlen_t newlen1=0; /* length with newbno1 */
187 xfs_extlen_t newlen2=0; /* length with newbno2 */
188 xfs_agblock_t wantend; /* end of target extent */
189
190 ASSERT(freelen >= wantlen);
191 freeend = freebno + freelen;
192 wantend = wantbno + wantlen;
193 /*
194 * We want to allocate from the start of a free extent if it is past
195 * the desired block or if we are allocating user data and the free
196 * extent is before desired block. The second case is there to allow
197 * for contiguous allocation from the remaining free space if the file
198 * grows in the short term.
199 */
200 if (freebno >= wantbno || (userdata && freeend < wantend)) {
201 if ((newbno1 = roundup(freebno, alignment)) >= freeend)
202 newbno1 = NULLAGBLOCK;
203 } else if (freeend >= wantend && alignment > 1) {
204 newbno1 = roundup(wantbno, alignment);
205 newbno2 = newbno1 - alignment;
206 if (newbno1 >= freeend)
207 newbno1 = NULLAGBLOCK;
208 else
209 newlen1 = XFS_EXTLEN_MIN(wantlen, freeend - newbno1);
210 if (newbno2 < freebno)
211 newbno2 = NULLAGBLOCK;
212 else
213 newlen2 = XFS_EXTLEN_MIN(wantlen, freeend - newbno2);
214 if (newbno1 != NULLAGBLOCK && newbno2 != NULLAGBLOCK) {
215 if (newlen1 < newlen2 ||
216 (newlen1 == newlen2 &&
217 XFS_ABSDIFF(newbno1, wantbno) >
218 XFS_ABSDIFF(newbno2, wantbno)))
219 newbno1 = newbno2;
220 } else if (newbno2 != NULLAGBLOCK)
221 newbno1 = newbno2;
222 } else if (freeend >= wantend) {
223 newbno1 = wantbno;
224 } else if (alignment > 1) {
225 newbno1 = roundup(freeend - wantlen, alignment);
226 if (newbno1 > freeend - wantlen &&
227 newbno1 - alignment >= freebno)
228 newbno1 -= alignment;
229 else if (newbno1 >= freeend)
230 newbno1 = NULLAGBLOCK;
231 } else
232 newbno1 = freeend - wantlen;
233 *newbnop = newbno1;
234 return newbno1 == NULLAGBLOCK ? 0 : XFS_ABSDIFF(newbno1, wantbno);
235}
236
237/*
238 * Fix up the length, based on mod and prod.
239 * len should be k * prod + mod for some k.
240 * If len is too small it is returned unchanged.
241 * If len hits maxlen it is left alone.
242 */
243STATIC void
244xfs_alloc_fix_len(
245 xfs_alloc_arg_t *args) /* allocation argument structure */
246{
247 xfs_extlen_t k;
248 xfs_extlen_t rlen;
249
250 ASSERT(args->mod < args->prod);
251 rlen = args->len;
252 ASSERT(rlen >= args->minlen);
253 ASSERT(rlen <= args->maxlen);
254 if (args->prod <= 1 || rlen < args->mod || rlen == args->maxlen ||
255 (args->mod == 0 && rlen < args->prod))
256 return;
257 k = rlen % args->prod;
258 if (k == args->mod)
259 return;
260 if (k > args->mod) {
261 if ((int)(rlen = rlen - k - args->mod) < (int)args->minlen)
262 return;
263 } else {
264 if ((int)(rlen = rlen - args->prod - (args->mod - k)) <
265 (int)args->minlen)
266 return;
267 }
268 ASSERT(rlen >= args->minlen);
269 ASSERT(rlen <= args->maxlen);
270 args->len = rlen;
271}
272
273/*
274 * Fix up length if there is too little space left in the a.g.
275 * Return 1 if ok, 0 if too little, should give up.
276 */
277STATIC int
278xfs_alloc_fix_minleft(
279 xfs_alloc_arg_t *args) /* allocation argument structure */
280{
281 xfs_agf_t *agf; /* a.g. freelist header */
282 int diff; /* free space difference */
283
284 if (args->minleft == 0)
285 return 1;
286 agf = XFS_BUF_TO_AGF(args->agbp);
287 diff = be32_to_cpu(agf->agf_freeblks)
288 - args->len - args->minleft;
289 if (diff >= 0)
290 return 1;
291 args->len += diff; /* shrink the allocated space */
292 if (args->len >= args->minlen)
293 return 1;
294 args->agbno = NULLAGBLOCK;
295 return 0;
296}
297
298/*
299 * Update the two btrees, logically removing from freespace the extent
300 * starting at rbno, rlen blocks. The extent is contained within the
301 * actual (current) free extent fbno for flen blocks.
302 * Flags are passed in indicating whether the cursors are set to the
303 * relevant records.
304 */
305STATIC int /* error code */
306xfs_alloc_fixup_trees(
307 xfs_btree_cur_t *cnt_cur, /* cursor for by-size btree */
308 xfs_btree_cur_t *bno_cur, /* cursor for by-block btree */
309 xfs_agblock_t fbno, /* starting block of free extent */
310 xfs_extlen_t flen, /* length of free extent */
311 xfs_agblock_t rbno, /* starting block of returned extent */
312 xfs_extlen_t rlen, /* length of returned extent */
313 int flags) /* flags, XFSA_FIXUP_... */
314{
315 int error; /* error code */
316 int i; /* operation results */
317 xfs_agblock_t nfbno1; /* first new free startblock */
318 xfs_agblock_t nfbno2; /* second new free startblock */
319 xfs_extlen_t nflen1=0; /* first new free length */
320 xfs_extlen_t nflen2=0; /* second new free length */
321
322 /*
323 * Look up the record in the by-size tree if necessary.
324 */
325 if (flags & XFSA_FIXUP_CNT_OK) {
326#ifdef DEBUG
327 if ((error = xfs_alloc_get_rec(cnt_cur, &nfbno1, &nflen1, &i)))
328 return error;
329 XFS_WANT_CORRUPTED_RETURN(
330 i == 1 && nfbno1 == fbno && nflen1 == flen);
331#endif
332 } else {
333 if ((error = xfs_alloc_lookup_eq(cnt_cur, fbno, flen, &i)))
334 return error;
335 XFS_WANT_CORRUPTED_RETURN(i == 1);
336 }
337 /*
338 * Look up the record in the by-block tree if necessary.
339 */
340 if (flags & XFSA_FIXUP_BNO_OK) {
341#ifdef DEBUG
342 if ((error = xfs_alloc_get_rec(bno_cur, &nfbno1, &nflen1, &i)))
343 return error;
344 XFS_WANT_CORRUPTED_RETURN(
345 i == 1 && nfbno1 == fbno && nflen1 == flen);
346#endif
347 } else {
348 if ((error = xfs_alloc_lookup_eq(bno_cur, fbno, flen, &i)))
349 return error;
350 XFS_WANT_CORRUPTED_RETURN(i == 1);
351 }
352
353#ifdef DEBUG
354 if (bno_cur->bc_nlevels == 1 && cnt_cur->bc_nlevels == 1) {
355 struct xfs_btree_block *bnoblock;
356 struct xfs_btree_block *cntblock;
357
358 bnoblock = XFS_BUF_TO_BLOCK(bno_cur->bc_bufs[0]);
359 cntblock = XFS_BUF_TO_BLOCK(cnt_cur->bc_bufs[0]);
360
361 XFS_WANT_CORRUPTED_RETURN(
362 bnoblock->bb_numrecs == cntblock->bb_numrecs);
363 }
364#endif
365
366 /*
367 * Deal with all four cases: the allocated record is contained
368 * within the freespace record, so we can have new freespace
369 * at either (or both) end, or no freespace remaining.
370 */
371 if (rbno == fbno && rlen == flen)
372 nfbno1 = nfbno2 = NULLAGBLOCK;
373 else if (rbno == fbno) {
374 nfbno1 = rbno + rlen;
375 nflen1 = flen - rlen;
376 nfbno2 = NULLAGBLOCK;
377 } else if (rbno + rlen == fbno + flen) {
378 nfbno1 = fbno;
379 nflen1 = flen - rlen;
380 nfbno2 = NULLAGBLOCK;
381 } else {
382 nfbno1 = fbno;
383 nflen1 = rbno - fbno;
384 nfbno2 = rbno + rlen;
385 nflen2 = (fbno + flen) - nfbno2;
386 }
387 /*
388 * Delete the entry from the by-size btree.
389 */
390 if ((error = xfs_btree_delete(cnt_cur, &i)))
391 return error;
392 XFS_WANT_CORRUPTED_RETURN(i == 1);
393 /*
394 * Add new by-size btree entry(s).
395 */
396 if (nfbno1 != NULLAGBLOCK) {
397 if ((error = xfs_alloc_lookup_eq(cnt_cur, nfbno1, nflen1, &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 if (nfbno2 != NULLAGBLOCK) {
405 if ((error = xfs_alloc_lookup_eq(cnt_cur, nfbno2, nflen2, &i)))
406 return error;
407 XFS_WANT_CORRUPTED_RETURN(i == 0);
408 if ((error = xfs_btree_insert(cnt_cur, &i)))
409 return error;
410 XFS_WANT_CORRUPTED_RETURN(i == 1);
411 }
412 /*
413 * Fix up the by-block btree entry(s).
414 */
415 if (nfbno1 == NULLAGBLOCK) {
416 /*
417 * No remaining freespace, just delete the by-block tree entry.
418 */
419 if ((error = xfs_btree_delete(bno_cur, &i)))
420 return error;
421 XFS_WANT_CORRUPTED_RETURN(i == 1);
422 } else {
423 /*
424 * Update the by-block entry to start later|be shorter.
425 */
426 if ((error = xfs_alloc_update(bno_cur, nfbno1, nflen1)))
427 return error;
428 }
429 if (nfbno2 != NULLAGBLOCK) {
430 /*
431 * 2 resulting free entries, need to add one.
432 */
433 if ((error = xfs_alloc_lookup_eq(bno_cur, nfbno2, nflen2, &i)))
434 return error;
435 XFS_WANT_CORRUPTED_RETURN(i == 0);
436 if ((error = xfs_btree_insert(bno_cur, &i)))
437 return error;
438 XFS_WANT_CORRUPTED_RETURN(i == 1);
439 }
440 return 0;
441}
442
443static bool
444xfs_agfl_verify(
445 struct xfs_buf *bp)
446{
447 struct xfs_mount *mp = bp->b_target->bt_mount;
448 struct xfs_agfl *agfl = XFS_BUF_TO_AGFL(bp);
449 int i;
450
451 if (!uuid_equal(&agfl->agfl_uuid, &mp->m_sb.sb_uuid))
452 return false;
453 if (be32_to_cpu(agfl->agfl_magicnum) != XFS_AGFL_MAGIC)
454 return false;
455 /*
456 * during growfs operations, the perag is not fully initialised,
457 * so we can't use it for any useful checking. growfs ensures we can't
458 * use it by using uncached buffers that don't have the perag attached
459 * so we can detect and avoid this problem.
460 */
461 if (bp->b_pag && be32_to_cpu(agfl->agfl_seqno) != bp->b_pag->pag_agno)
462 return false;
463
464 for (i = 0; i < XFS_AGFL_SIZE(mp); i++) {
465 if (be32_to_cpu(agfl->agfl_bno[i]) != NULLAGBLOCK &&
466 be32_to_cpu(agfl->agfl_bno[i]) >= mp->m_sb.sb_agblocks)
467 return false;
468 }
469 return true;
470}
471
472static void
473xfs_agfl_read_verify(
474 struct xfs_buf *bp)
475{
476 struct xfs_mount *mp = bp->b_target->bt_mount;
477
478 /*
479 * There is no verification of non-crc AGFLs because mkfs does not
480 * initialise the AGFL to zero or NULL. Hence the only valid part of the
481 * AGFL is what the AGF says is active. We can't get to the AGF, so we
482 * can't verify just those entries are valid.
483 */
484 if (!xfs_sb_version_hascrc(&mp->m_sb))
485 return;
486
487 if (!xfs_buf_verify_cksum(bp, XFS_AGFL_CRC_OFF))
488 xfs_buf_ioerror(bp, EFSBADCRC);
489 else if (!xfs_agfl_verify(bp))
490 xfs_buf_ioerror(bp, EFSCORRUPTED);
491
492 if (bp->b_error)
493 xfs_verifier_error(bp);
494}
495
496static void
497xfs_agfl_write_verify(
498 struct xfs_buf *bp)
499{
500 struct xfs_mount *mp = bp->b_target->bt_mount;
501 struct xfs_buf_log_item *bip = bp->b_fspriv;
502
503 /* no verification of non-crc AGFLs */
504 if (!xfs_sb_version_hascrc(&mp->m_sb))
505 return;
506
507 if (!xfs_agfl_verify(bp)) {
508 xfs_buf_ioerror(bp, EFSCORRUPTED);
509 xfs_verifier_error(bp);
510 return;
511 }
512
513 if (bip)
514 XFS_BUF_TO_AGFL(bp)->agfl_lsn = cpu_to_be64(bip->bli_item.li_lsn);
515
516 xfs_buf_update_cksum(bp, XFS_AGFL_CRC_OFF);
517}
518
519const struct xfs_buf_ops xfs_agfl_buf_ops = {
520 .verify_read = xfs_agfl_read_verify,
521 .verify_write = xfs_agfl_write_verify,
522};
523
524/*
525 * Read in the allocation group free block array.
526 */
527STATIC int /* error */
528xfs_alloc_read_agfl(
529 xfs_mount_t *mp, /* mount point structure */
530 xfs_trans_t *tp, /* transaction pointer */
531 xfs_agnumber_t agno, /* allocation group number */
532 xfs_buf_t **bpp) /* buffer for the ag free block array */
533{
534 xfs_buf_t *bp; /* return value */
535 int error;
536
537 ASSERT(agno != NULLAGNUMBER);
538 error = xfs_trans_read_buf(
539 mp, tp, mp->m_ddev_targp,
540 XFS_AG_DADDR(mp, agno, XFS_AGFL_DADDR(mp)),
541 XFS_FSS_TO_BB(mp, 1), 0, &bp, &xfs_agfl_buf_ops);
542 if (error)
543 return error;
544 ASSERT(!xfs_buf_geterror(bp));
545 xfs_buf_set_ref(bp, XFS_AGFL_REF);
546 *bpp = bp;
547 return 0;
548}
549
550STATIC int
551xfs_alloc_update_counters(
552 struct xfs_trans *tp,
553 struct xfs_perag *pag,
554 struct xfs_buf *agbp,
555 long len)
556{
557 struct xfs_agf *agf = XFS_BUF_TO_AGF(agbp);
558
559 pag->pagf_freeblks += len;
560 be32_add_cpu(&agf->agf_freeblks, len);
561
562 xfs_trans_agblocks_delta(tp, len);
563 if (unlikely(be32_to_cpu(agf->agf_freeblks) >
564 be32_to_cpu(agf->agf_length)))
565 return EFSCORRUPTED;
566
567 xfs_alloc_log_agf(tp, agbp, XFS_AGF_FREEBLKS);
568 return 0;
569}
570
571/*
572 * Allocation group level functions.
573 */
574
575/*
576 * Allocate a variable extent in the allocation group agno.
577 * Type and bno are used to determine where in the allocation group the
578 * extent will start.
579 * Extent's length (returned in *len) will be between minlen and maxlen,
580 * and of the form k * prod + mod unless there's nothing that large.
581 * Return the starting a.g. block, or NULLAGBLOCK if we can't do it.
582 */
583STATIC int /* error */
584xfs_alloc_ag_vextent(
585 xfs_alloc_arg_t *args) /* argument structure for allocation */
586{
587 int error=0;
588
589 ASSERT(args->minlen > 0);
590 ASSERT(args->maxlen > 0);
591 ASSERT(args->minlen <= args->maxlen);
592 ASSERT(args->mod < args->prod);
593 ASSERT(args->alignment > 0);
594 /*
595 * Branch to correct routine based on the type.
596 */
597 args->wasfromfl = 0;
598 switch (args->type) {
599 case XFS_ALLOCTYPE_THIS_AG:
600 error = xfs_alloc_ag_vextent_size(args);
601 break;
602 case XFS_ALLOCTYPE_NEAR_BNO:
603 error = xfs_alloc_ag_vextent_near(args);
604 break;
605 case XFS_ALLOCTYPE_THIS_BNO:
606 error = xfs_alloc_ag_vextent_exact(args);
607 break;
608 default:
609 ASSERT(0);
610 /* NOTREACHED */
611 }
612
613 if (error || args->agbno == NULLAGBLOCK)
614 return error;
615
616 ASSERT(args->len >= args->minlen);
617 ASSERT(args->len <= args->maxlen);
618 ASSERT(!args->wasfromfl || !args->isfl);
619 ASSERT(args->agbno % args->alignment == 0);
620
621 if (!args->wasfromfl) {
622 error = xfs_alloc_update_counters(args->tp, args->pag,
623 args->agbp,
624 -((long)(args->len)));
625 if (error)
626 return error;
627
628 ASSERT(!xfs_extent_busy_search(args->mp, args->agno,
629 args->agbno, args->len));
630 }
631
632 if (!args->isfl) {
633 xfs_trans_mod_sb(args->tp, args->wasdel ?
634 XFS_TRANS_SB_RES_FDBLOCKS :
635 XFS_TRANS_SB_FDBLOCKS,
636 -((long)(args->len)));
637 }
638
639 XFS_STATS_INC(xs_allocx);
640 XFS_STATS_ADD(xs_allocb, args->len);
641 return error;
642}
643
644/*
645 * Allocate a variable extent at exactly agno/bno.
646 * Extent's length (returned in *len) will be between minlen and maxlen,
647 * and of the form k * prod + mod unless there's nothing that large.
648 * Return the starting a.g. block (bno), or NULLAGBLOCK if we can't do it.
649 */
650STATIC int /* error */
651xfs_alloc_ag_vextent_exact(
652 xfs_alloc_arg_t *args) /* allocation argument structure */
653{
654 xfs_btree_cur_t *bno_cur;/* by block-number btree cursor */
655 xfs_btree_cur_t *cnt_cur;/* by count btree cursor */
656 int error;
657 xfs_agblock_t fbno; /* start block of found extent */
658 xfs_extlen_t flen; /* length of found extent */
659 xfs_agblock_t tbno; /* start block of trimmed extent */
660 xfs_extlen_t tlen; /* length of trimmed extent */
661 xfs_agblock_t tend; /* end block of trimmed extent */
662 int i; /* success/failure of operation */
663
664 ASSERT(args->alignment == 1);
665
666 /*
667 * Allocate/initialize a cursor for the by-number freespace btree.
668 */
669 bno_cur = xfs_allocbt_init_cursor(args->mp, args->tp, args->agbp,
670 args->agno, XFS_BTNUM_BNO);
671
672 /*
673 * Lookup bno and minlen in the btree (minlen is irrelevant, really).
674 * Look for the closest free block <= bno, it must contain bno
675 * if any free block does.
676 */
677 error = xfs_alloc_lookup_le(bno_cur, args->agbno, args->minlen, &i);
678 if (error)
679 goto error0;
680 if (!i)
681 goto not_found;
682
683 /*
684 * Grab the freespace record.
685 */
686 error = xfs_alloc_get_rec(bno_cur, &fbno, &flen, &i);
687 if (error)
688 goto error0;
689 XFS_WANT_CORRUPTED_GOTO(i == 1, error0);
690 ASSERT(fbno <= args->agbno);
691
692 /*
693 * Check for overlapping busy extents.
694 */
695 xfs_extent_busy_trim(args, fbno, flen, &tbno, &tlen);
696
697 /*
698 * Give up if the start of the extent is busy, or the freespace isn't
699 * long enough for the minimum request.
700 */
701 if (tbno > args->agbno)
702 goto not_found;
703 if (tlen < args->minlen)
704 goto not_found;
705 tend = tbno + tlen;
706 if (tend < args->agbno + args->minlen)
707 goto not_found;
708
709 /*
710 * End of extent will be smaller of the freespace end and the
711 * maximal requested end.
712 *
713 * Fix the length according to mod and prod if given.
714 */
715 args->len = XFS_AGBLOCK_MIN(tend, args->agbno + args->maxlen)
716 - args->agbno;
717 xfs_alloc_fix_len(args);
718 if (!xfs_alloc_fix_minleft(args))
719 goto not_found;
720
721 ASSERT(args->agbno + args->len <= tend);
722
723 /*
724 * We are allocating agbno for args->len
725 * Allocate/initialize a cursor for the by-size btree.
726 */
727 cnt_cur = xfs_allocbt_init_cursor(args->mp, args->tp, args->agbp,
728 args->agno, XFS_BTNUM_CNT);
729 ASSERT(args->agbno + args->len <=
730 be32_to_cpu(XFS_BUF_TO_AGF(args->agbp)->agf_length));
731 error = xfs_alloc_fixup_trees(cnt_cur, bno_cur, fbno, flen, args->agbno,
732 args->len, XFSA_FIXUP_BNO_OK);
733 if (error) {
734 xfs_btree_del_cursor(cnt_cur, XFS_BTREE_ERROR);
735 goto error0;
736 }
737
738 xfs_btree_del_cursor(bno_cur, XFS_BTREE_NOERROR);
739 xfs_btree_del_cursor(cnt_cur, XFS_BTREE_NOERROR);
740
741 args->wasfromfl = 0;
742 trace_xfs_alloc_exact_done(args);
743 return 0;
744
745not_found:
746 /* Didn't find it, return null. */
747 xfs_btree_del_cursor(bno_cur, XFS_BTREE_NOERROR);
748 args->agbno = NULLAGBLOCK;
749 trace_xfs_alloc_exact_notfound(args);
750 return 0;
751
752error0:
753 xfs_btree_del_cursor(bno_cur, XFS_BTREE_ERROR);
754 trace_xfs_alloc_exact_error(args);
755 return error;
756}
757
758/*
759 * Search the btree in a given direction via the search cursor and compare
760 * the records found against the good extent we've already found.
761 */
762STATIC int
763xfs_alloc_find_best_extent(
764 struct xfs_alloc_arg *args, /* allocation argument structure */
765 struct xfs_btree_cur **gcur, /* good cursor */
766 struct xfs_btree_cur **scur, /* searching cursor */
767 xfs_agblock_t gdiff, /* difference for search comparison */
768 xfs_agblock_t *sbno, /* extent found by search */
769 xfs_extlen_t *slen, /* extent length */
770 xfs_agblock_t *sbnoa, /* aligned extent found by search */
771 xfs_extlen_t *slena, /* aligned extent length */
772 int dir) /* 0 = search right, 1 = search left */
773{
774 xfs_agblock_t new;
775 xfs_agblock_t sdiff;
776 int error;
777 int i;
778
779 /* The good extent is perfect, no need to search. */
780 if (!gdiff)
781 goto out_use_good;
782
783 /*
784 * Look until we find a better one, run out of space or run off the end.
785 */
786 do {
787 error = xfs_alloc_get_rec(*scur, sbno, slen, &i);
788 if (error)
789 goto error0;
790 XFS_WANT_CORRUPTED_GOTO(i == 1, error0);
791 xfs_alloc_compute_aligned(args, *sbno, *slen, sbnoa, slena);
792
793 /*
794 * The good extent is closer than this one.
795 */
796 if (!dir) {
797 if (*sbnoa >= args->agbno + gdiff)
798 goto out_use_good;
799 } else {
800 if (*sbnoa <= args->agbno - gdiff)
801 goto out_use_good;
802 }
803
804 /*
805 * Same distance, compare length and pick the best.
806 */
807 if (*slena >= args->minlen) {
808 args->len = XFS_EXTLEN_MIN(*slena, args->maxlen);
809 xfs_alloc_fix_len(args);
810
811 sdiff = xfs_alloc_compute_diff(args->agbno, args->len,
812 args->alignment,
813 args->userdata, *sbnoa,
814 *slena, &new);
815
816 /*
817 * Choose closer size and invalidate other cursor.
818 */
819 if (sdiff < gdiff)
820 goto out_use_search;
821 goto out_use_good;
822 }
823
824 if (!dir)
825 error = xfs_btree_increment(*scur, 0, &i);
826 else
827 error = xfs_btree_decrement(*scur, 0, &i);
828 if (error)
829 goto error0;
830 } while (i);
831
832out_use_good:
833 xfs_btree_del_cursor(*scur, XFS_BTREE_NOERROR);
834 *scur = NULL;
835 return 0;
836
837out_use_search:
838 xfs_btree_del_cursor(*gcur, XFS_BTREE_NOERROR);
839 *gcur = NULL;
840 return 0;
841
842error0:
843 /* caller invalidates cursors */
844 return error;
845}
846
847/*
848 * Allocate a variable extent near bno in the allocation group agno.
849 * Extent's length (returned in len) will be between minlen and maxlen,
850 * and of the form k * prod + mod unless there's nothing that large.
851 * Return the starting a.g. block, or NULLAGBLOCK if we can't do it.
852 */
853STATIC int /* error */
854xfs_alloc_ag_vextent_near(
855 xfs_alloc_arg_t *args) /* allocation argument structure */
856{
857 xfs_btree_cur_t *bno_cur_gt; /* cursor for bno btree, right side */
858 xfs_btree_cur_t *bno_cur_lt; /* cursor for bno btree, left side */
859 xfs_btree_cur_t *cnt_cur; /* cursor for count btree */
860 xfs_agblock_t gtbno; /* start bno of right side entry */
861 xfs_agblock_t gtbnoa; /* aligned ... */
862 xfs_extlen_t gtdiff; /* difference to right side entry */
863 xfs_extlen_t gtlen; /* length of right side entry */
864 xfs_extlen_t gtlena; /* aligned ... */
865 xfs_agblock_t gtnew; /* useful start bno of right side */
866 int error; /* error code */
867 int i; /* result code, temporary */
868 int j; /* result code, temporary */
869 xfs_agblock_t ltbno; /* start bno of left side entry */
870 xfs_agblock_t ltbnoa; /* aligned ... */
871 xfs_extlen_t ltdiff; /* difference to left side entry */
872 xfs_extlen_t ltlen; /* length of left side entry */
873 xfs_extlen_t ltlena; /* aligned ... */
874 xfs_agblock_t ltnew; /* useful start bno of left side */
875 xfs_extlen_t rlen; /* length of returned extent */
876 int forced = 0;
877#ifdef DEBUG
878 /*
879 * Randomly don't execute the first algorithm.
880 */
881 int dofirst; /* set to do first algorithm */
882
883 dofirst = prandom_u32() & 1;
884#endif
885
886restart:
887 bno_cur_lt = NULL;
888 bno_cur_gt = NULL;
889 ltlen = 0;
890 gtlena = 0;
891 ltlena = 0;
892
893 /*
894 * Get a cursor for the by-size btree.
895 */
896 cnt_cur = xfs_allocbt_init_cursor(args->mp, args->tp, args->agbp,
897 args->agno, XFS_BTNUM_CNT);
898
899 /*
900 * See if there are any free extents as big as maxlen.
901 */
902 if ((error = xfs_alloc_lookup_ge(cnt_cur, 0, args->maxlen, &i)))
903 goto error0;
904 /*
905 * If none, then pick up the last entry in the tree unless the
906 * tree is empty.
907 */
908 if (!i) {
909 if ((error = xfs_alloc_ag_vextent_small(args, cnt_cur, <bno,
910 <len, &i)))
911 goto error0;
912 if (i == 0 || ltlen == 0) {
913 xfs_btree_del_cursor(cnt_cur, XFS_BTREE_NOERROR);
914 trace_xfs_alloc_near_noentry(args);
915 return 0;
916 }
917 ASSERT(i == 1);
918 }
919 args->wasfromfl = 0;
920
921 /*
922 * First algorithm.
923 * If the requested extent is large wrt the freespaces available
924 * in this a.g., then the cursor will be pointing to a btree entry
925 * near the right edge of the tree. If it's in the last btree leaf
926 * block, then we just examine all the entries in that block
927 * that are big enough, and pick the best one.
928 * This is written as a while loop so we can break out of it,
929 * but we never loop back to the top.
930 */
931 while (xfs_btree_islastblock(cnt_cur, 0)) {
932 xfs_extlen_t bdiff;
933 int besti=0;
934 xfs_extlen_t blen=0;
935 xfs_agblock_t bnew=0;
936
937#ifdef DEBUG
938 if (dofirst)
939 break;
940#endif
941 /*
942 * Start from the entry that lookup found, sequence through
943 * all larger free blocks. If we're actually pointing at a
944 * record smaller than maxlen, go to the start of this block,
945 * and skip all those smaller than minlen.
946 */
947 if (ltlen || args->alignment > 1) {
948 cnt_cur->bc_ptrs[0] = 1;
949 do {
950 if ((error = xfs_alloc_get_rec(cnt_cur, <bno,
951 <len, &i)))
952 goto error0;
953 XFS_WANT_CORRUPTED_GOTO(i == 1, error0);
954 if (ltlen >= args->minlen)
955 break;
956 if ((error = xfs_btree_increment(cnt_cur, 0, &i)))
957 goto error0;
958 } while (i);
959 ASSERT(ltlen >= args->minlen);
960 if (!i)
961 break;
962 }
963 i = cnt_cur->bc_ptrs[0];
964 for (j = 1, blen = 0, bdiff = 0;
965 !error && j && (blen < args->maxlen || bdiff > 0);
966 error = xfs_btree_increment(cnt_cur, 0, &j)) {
967 /*
968 * For each entry, decide if it's better than
969 * the previous best entry.
970 */
971 if ((error = xfs_alloc_get_rec(cnt_cur, <bno, <len, &i)))
972 goto error0;
973 XFS_WANT_CORRUPTED_GOTO(i == 1, error0);
974 xfs_alloc_compute_aligned(args, ltbno, ltlen,
975 <bnoa, <lena);
976 if (ltlena < args->minlen)
977 continue;
978 args->len = XFS_EXTLEN_MIN(ltlena, args->maxlen);
979 xfs_alloc_fix_len(args);
980 ASSERT(args->len >= args->minlen);
981 if (args->len < blen)
982 continue;
983 ltdiff = xfs_alloc_compute_diff(args->agbno, args->len,
984 args->alignment, args->userdata, ltbnoa,
985 ltlena, <new);
986 if (ltnew != NULLAGBLOCK &&
987 (args->len > blen || ltdiff < bdiff)) {
988 bdiff = ltdiff;
989 bnew = ltnew;
990 blen = args->len;
991 besti = cnt_cur->bc_ptrs[0];
992 }
993 }
994 /*
995 * It didn't work. We COULD be in a case where
996 * there's a good record somewhere, so try again.
997 */
998 if (blen == 0)
999 break;
1000 /*
1001 * Point at the best entry, and retrieve it again.
1002 */
1003 cnt_cur->bc_ptrs[0] = besti;
1004 if ((error = xfs_alloc_get_rec(cnt_cur, <bno, <len, &i)))
1005 goto error0;
1006 XFS_WANT_CORRUPTED_GOTO(i == 1, error0);
1007 ASSERT(ltbno + ltlen <= be32_to_cpu(XFS_BUF_TO_AGF(args->agbp)->agf_length));
1008 args->len = blen;
1009 if (!xfs_alloc_fix_minleft(args)) {
1010 xfs_btree_del_cursor(cnt_cur, XFS_BTREE_NOERROR);
1011 trace_xfs_alloc_near_nominleft(args);
1012 return 0;
1013 }
1014 blen = args->len;
1015 /*
1016 * We are allocating starting at bnew for blen blocks.
1017 */
1018 args->agbno = bnew;
1019 ASSERT(bnew >= ltbno);
1020 ASSERT(bnew + blen <= ltbno + ltlen);
1021 /*
1022 * Set up a cursor for the by-bno tree.
1023 */
1024 bno_cur_lt = xfs_allocbt_init_cursor(args->mp, args->tp,
1025 args->agbp, args->agno, XFS_BTNUM_BNO);
1026 /*
1027 * Fix up the btree entries.
1028 */
1029 if ((error = xfs_alloc_fixup_trees(cnt_cur, bno_cur_lt, ltbno,
1030 ltlen, bnew, blen, XFSA_FIXUP_CNT_OK)))
1031 goto error0;
1032 xfs_btree_del_cursor(cnt_cur, XFS_BTREE_NOERROR);
1033 xfs_btree_del_cursor(bno_cur_lt, XFS_BTREE_NOERROR);
1034
1035 trace_xfs_alloc_near_first(args);
1036 return 0;
1037 }
1038 /*
1039 * Second algorithm.
1040 * Search in the by-bno tree to the left and to the right
1041 * simultaneously, until in each case we find a space big enough,
1042 * or run into the edge of the tree. When we run into the edge,
1043 * we deallocate that cursor.
1044 * If both searches succeed, we compare the two spaces and pick
1045 * the better one.
1046 * With alignment, it's possible for both to fail; the upper
1047 * level algorithm that picks allocation groups for allocations
1048 * is not supposed to do this.
1049 */
1050 /*
1051 * Allocate and initialize the cursor for the leftward search.
1052 */
1053 bno_cur_lt = xfs_allocbt_init_cursor(args->mp, args->tp, args->agbp,
1054 args->agno, XFS_BTNUM_BNO);
1055 /*
1056 * Lookup <= bno to find the leftward search's starting point.
1057 */
1058 if ((error = xfs_alloc_lookup_le(bno_cur_lt, args->agbno, args->maxlen, &i)))
1059 goto error0;
1060 if (!i) {
1061 /*
1062 * Didn't find anything; use this cursor for the rightward
1063 * search.
1064 */
1065 bno_cur_gt = bno_cur_lt;
1066 bno_cur_lt = NULL;
1067 }
1068 /*
1069 * Found something. Duplicate the cursor for the rightward search.
1070 */
1071 else if ((error = xfs_btree_dup_cursor(bno_cur_lt, &bno_cur_gt)))
1072 goto error0;
1073 /*
1074 * Increment the cursor, so we will point at the entry just right
1075 * of the leftward entry if any, or to the leftmost entry.
1076 */
1077 if ((error = xfs_btree_increment(bno_cur_gt, 0, &i)))
1078 goto error0;
1079 if (!i) {
1080 /*
1081 * It failed, there are no rightward entries.
1082 */
1083 xfs_btree_del_cursor(bno_cur_gt, XFS_BTREE_NOERROR);
1084 bno_cur_gt = NULL;
1085 }
1086 /*
1087 * Loop going left with the leftward cursor, right with the
1088 * rightward cursor, until either both directions give up or
1089 * we find an entry at least as big as minlen.
1090 */
1091 do {
1092 if (bno_cur_lt) {
1093 if ((error = xfs_alloc_get_rec(bno_cur_lt, <bno, <len, &i)))
1094 goto error0;
1095 XFS_WANT_CORRUPTED_GOTO(i == 1, error0);
1096 xfs_alloc_compute_aligned(args, ltbno, ltlen,
1097 <bnoa, <lena);
1098 if (ltlena >= args->minlen)
1099 break;
1100 if ((error = xfs_btree_decrement(bno_cur_lt, 0, &i)))
1101 goto error0;
1102 if (!i) {
1103 xfs_btree_del_cursor(bno_cur_lt,
1104 XFS_BTREE_NOERROR);
1105 bno_cur_lt = NULL;
1106 }
1107 }
1108 if (bno_cur_gt) {
1109 if ((error = xfs_alloc_get_rec(bno_cur_gt, >bno, >len, &i)))
1110 goto error0;
1111 XFS_WANT_CORRUPTED_GOTO(i == 1, error0);
1112 xfs_alloc_compute_aligned(args, gtbno, gtlen,
1113 >bnoa, >lena);
1114 if (gtlena >= args->minlen)
1115 break;
1116 if ((error = xfs_btree_increment(bno_cur_gt, 0, &i)))
1117 goto error0;
1118 if (!i) {
1119 xfs_btree_del_cursor(bno_cur_gt,
1120 XFS_BTREE_NOERROR);
1121 bno_cur_gt = NULL;
1122 }
1123 }
1124 } while (bno_cur_lt || bno_cur_gt);
1125
1126 /*
1127 * Got both cursors still active, need to find better entry.
1128 */
1129 if (bno_cur_lt && bno_cur_gt) {
1130 if (ltlena >= args->minlen) {
1131 /*
1132 * Left side is good, look for a right side entry.
1133 */
1134 args->len = XFS_EXTLEN_MIN(ltlena, args->maxlen);
1135 xfs_alloc_fix_len(args);
1136 ltdiff = xfs_alloc_compute_diff(args->agbno, args->len,
1137 args->alignment, args->userdata, ltbnoa,
1138 ltlena, <new);
1139
1140 error = xfs_alloc_find_best_extent(args,
1141 &bno_cur_lt, &bno_cur_gt,
1142 ltdiff, >bno, >len,
1143 >bnoa, >lena,
1144 0 /* search right */);
1145 } else {
1146 ASSERT(gtlena >= args->minlen);
1147
1148 /*
1149 * Right side is good, look for a left side entry.
1150 */
1151 args->len = XFS_EXTLEN_MIN(gtlena, args->maxlen);
1152 xfs_alloc_fix_len(args);
1153 gtdiff = xfs_alloc_compute_diff(args->agbno, args->len,
1154 args->alignment, args->userdata, gtbnoa,
1155 gtlena, >new);
1156
1157 error = xfs_alloc_find_best_extent(args,
1158 &bno_cur_gt, &bno_cur_lt,
1159 gtdiff, <bno, <len,
1160 <bnoa, <lena,
1161 1 /* search left */);
1162 }
1163
1164 if (error)
1165 goto error0;
1166 }
1167
1168 /*
1169 * If we couldn't get anything, give up.
1170 */
1171 if (bno_cur_lt == NULL && bno_cur_gt == NULL) {
1172 xfs_btree_del_cursor(cnt_cur, XFS_BTREE_NOERROR);
1173
1174 if (!forced++) {
1175 trace_xfs_alloc_near_busy(args);
1176 xfs_log_force(args->mp, XFS_LOG_SYNC);
1177 goto restart;
1178 }
1179 trace_xfs_alloc_size_neither(args);
1180 args->agbno = NULLAGBLOCK;
1181 return 0;
1182 }
1183
1184 /*
1185 * At this point we have selected a freespace entry, either to the
1186 * left or to the right. If it's on the right, copy all the
1187 * useful variables to the "left" set so we only have one
1188 * copy of this code.
1189 */
1190 if (bno_cur_gt) {
1191 bno_cur_lt = bno_cur_gt;
1192 bno_cur_gt = NULL;
1193 ltbno = gtbno;
1194 ltbnoa = gtbnoa;
1195 ltlen = gtlen;
1196 ltlena = gtlena;
1197 j = 1;
1198 } else
1199 j = 0;
1200
1201 /*
1202 * Fix up the length and compute the useful address.
1203 */
1204 args->len = XFS_EXTLEN_MIN(ltlena, args->maxlen);
1205 xfs_alloc_fix_len(args);
1206 if (!xfs_alloc_fix_minleft(args)) {
1207 trace_xfs_alloc_near_nominleft(args);
1208 xfs_btree_del_cursor(bno_cur_lt, XFS_BTREE_NOERROR);
1209 xfs_btree_del_cursor(cnt_cur, XFS_BTREE_NOERROR);
1210 return 0;
1211 }
1212 rlen = args->len;
1213 (void)xfs_alloc_compute_diff(args->agbno, rlen, args->alignment,
1214 args->userdata, ltbnoa, ltlena, <new);
1215 ASSERT(ltnew >= ltbno);
1216 ASSERT(ltnew + rlen <= ltbnoa + ltlena);
1217 ASSERT(ltnew + rlen <= be32_to_cpu(XFS_BUF_TO_AGF(args->agbp)->agf_length));
1218 args->agbno = ltnew;
1219
1220 if ((error = xfs_alloc_fixup_trees(cnt_cur, bno_cur_lt, ltbno, ltlen,
1221 ltnew, rlen, XFSA_FIXUP_BNO_OK)))
1222 goto error0;
1223
1224 if (j)
1225 trace_xfs_alloc_near_greater(args);
1226 else
1227 trace_xfs_alloc_near_lesser(args);
1228
1229 xfs_btree_del_cursor(cnt_cur, XFS_BTREE_NOERROR);
1230 xfs_btree_del_cursor(bno_cur_lt, XFS_BTREE_NOERROR);
1231 return 0;
1232
1233 error0:
1234 trace_xfs_alloc_near_error(args);
1235 if (cnt_cur != NULL)
1236 xfs_btree_del_cursor(cnt_cur, XFS_BTREE_ERROR);
1237 if (bno_cur_lt != NULL)
1238 xfs_btree_del_cursor(bno_cur_lt, XFS_BTREE_ERROR);
1239 if (bno_cur_gt != NULL)
1240 xfs_btree_del_cursor(bno_cur_gt, XFS_BTREE_ERROR);
1241 return error;
1242}
1243
1244/*
1245 * Allocate a variable extent anywhere in the allocation group agno.
1246 * Extent's length (returned in len) will be between minlen and maxlen,
1247 * and of the form k * prod + mod unless there's nothing that large.
1248 * Return the starting a.g. block, or NULLAGBLOCK if we can't do it.
1249 */
1250STATIC int /* error */
1251xfs_alloc_ag_vextent_size(
1252 xfs_alloc_arg_t *args) /* allocation argument structure */
1253{
1254 xfs_btree_cur_t *bno_cur; /* cursor for bno btree */
1255 xfs_btree_cur_t *cnt_cur; /* cursor for cnt btree */
1256 int error; /* error result */
1257 xfs_agblock_t fbno; /* start of found freespace */
1258 xfs_extlen_t flen; /* length of found freespace */
1259 int i; /* temp status variable */
1260 xfs_agblock_t rbno; /* returned block number */
1261 xfs_extlen_t rlen; /* length of returned extent */
1262 int forced = 0;
1263
1264restart:
1265 /*
1266 * Allocate and initialize a cursor for the by-size btree.
1267 */
1268 cnt_cur = xfs_allocbt_init_cursor(args->mp, args->tp, args->agbp,
1269 args->agno, XFS_BTNUM_CNT);
1270 bno_cur = NULL;
1271
1272 /*
1273 * Look for an entry >= maxlen+alignment-1 blocks.
1274 */
1275 if ((error = xfs_alloc_lookup_ge(cnt_cur, 0,
1276 args->maxlen + args->alignment - 1, &i)))
1277 goto error0;
1278
1279 /*
1280 * If none or we have busy extents that we cannot allocate from, then
1281 * we have to settle for a smaller extent. In the case that there are
1282 * no large extents, this will return the last entry in the tree unless
1283 * the tree is empty. In the case that there are only busy large
1284 * extents, this will return the largest small extent unless there
1285 * are no smaller extents available.
1286 */
1287 if (!i || forced > 1) {
1288 error = xfs_alloc_ag_vextent_small(args, cnt_cur,
1289 &fbno, &flen, &i);
1290 if (error)
1291 goto error0;
1292 if (i == 0 || flen == 0) {
1293 xfs_btree_del_cursor(cnt_cur, XFS_BTREE_NOERROR);
1294 trace_xfs_alloc_size_noentry(args);
1295 return 0;
1296 }
1297 ASSERT(i == 1);
1298 xfs_alloc_compute_aligned(args, fbno, flen, &rbno, &rlen);
1299 } else {
1300 /*
1301 * Search for a non-busy extent that is large enough.
1302 * If we are at low space, don't check, or if we fall of
1303 * the end of the btree, turn off the busy check and
1304 * restart.
1305 */
1306 for (;;) {
1307 error = xfs_alloc_get_rec(cnt_cur, &fbno, &flen, &i);
1308 if (error)
1309 goto error0;
1310 XFS_WANT_CORRUPTED_GOTO(i == 1, error0);
1311
1312 xfs_alloc_compute_aligned(args, fbno, flen,
1313 &rbno, &rlen);
1314
1315 if (rlen >= args->maxlen)
1316 break;
1317
1318 error = xfs_btree_increment(cnt_cur, 0, &i);
1319 if (error)
1320 goto error0;
1321 if (i == 0) {
1322 /*
1323 * Our only valid extents must have been busy.
1324 * Make it unbusy by forcing the log out and
1325 * retrying. If we've been here before, forcing
1326 * the log isn't making the extents available,
1327 * which means they have probably been freed in
1328 * this transaction. In that case, we have to
1329 * give up on them and we'll attempt a minlen
1330 * allocation the next time around.
1331 */
1332 xfs_btree_del_cursor(cnt_cur,
1333 XFS_BTREE_NOERROR);
1334 trace_xfs_alloc_size_busy(args);
1335 if (!forced++)
1336 xfs_log_force(args->mp, XFS_LOG_SYNC);
1337 goto restart;
1338 }
1339 }
1340 }
1341
1342 /*
1343 * In the first case above, we got the last entry in the
1344 * by-size btree. Now we check to see if the space hits maxlen
1345 * once aligned; if not, we search left for something better.
1346 * This can't happen in the second case above.
1347 */
1348 rlen = XFS_EXTLEN_MIN(args->maxlen, rlen);
1349 XFS_WANT_CORRUPTED_GOTO(rlen == 0 ||
1350 (rlen <= flen && rbno + rlen <= fbno + flen), error0);
1351 if (rlen < args->maxlen) {
1352 xfs_agblock_t bestfbno;
1353 xfs_extlen_t bestflen;
1354 xfs_agblock_t bestrbno;
1355 xfs_extlen_t bestrlen;
1356
1357 bestrlen = rlen;
1358 bestrbno = rbno;
1359 bestflen = flen;
1360 bestfbno = fbno;
1361 for (;;) {
1362 if ((error = xfs_btree_decrement(cnt_cur, 0, &i)))
1363 goto error0;
1364 if (i == 0)
1365 break;
1366 if ((error = xfs_alloc_get_rec(cnt_cur, &fbno, &flen,
1367 &i)))
1368 goto error0;
1369 XFS_WANT_CORRUPTED_GOTO(i == 1, error0);
1370 if (flen < bestrlen)
1371 break;
1372 xfs_alloc_compute_aligned(args, fbno, flen,
1373 &rbno, &rlen);
1374 rlen = XFS_EXTLEN_MIN(args->maxlen, rlen);
1375 XFS_WANT_CORRUPTED_GOTO(rlen == 0 ||
1376 (rlen <= flen && rbno + rlen <= fbno + flen),
1377 error0);
1378 if (rlen > bestrlen) {
1379 bestrlen = rlen;
1380 bestrbno = rbno;
1381 bestflen = flen;
1382 bestfbno = fbno;
1383 if (rlen == args->maxlen)
1384 break;
1385 }
1386 }
1387 if ((error = xfs_alloc_lookup_eq(cnt_cur, bestfbno, bestflen,
1388 &i)))
1389 goto error0;
1390 XFS_WANT_CORRUPTED_GOTO(i == 1, error0);
1391 rlen = bestrlen;
1392 rbno = bestrbno;
1393 flen = bestflen;
1394 fbno = bestfbno;
1395 }
1396 args->wasfromfl = 0;
1397 /*
1398 * Fix up the length.
1399 */
1400 args->len = rlen;
1401 if (rlen < args->minlen) {
1402 if (!forced++) {
1403 xfs_btree_del_cursor(cnt_cur, XFS_BTREE_NOERROR);
1404 trace_xfs_alloc_size_busy(args);
1405 xfs_log_force(args->mp, XFS_LOG_SYNC);
1406 goto restart;
1407 }
1408 goto out_nominleft;
1409 }
1410 xfs_alloc_fix_len(args);
1411
1412 if (!xfs_alloc_fix_minleft(args))
1413 goto out_nominleft;
1414 rlen = args->len;
1415 XFS_WANT_CORRUPTED_GOTO(rlen <= flen, error0);
1416 /*
1417 * Allocate and initialize a cursor for the by-block tree.
1418 */
1419 bno_cur = xfs_allocbt_init_cursor(args->mp, args->tp, args->agbp,
1420 args->agno, XFS_BTNUM_BNO);
1421 if ((error = xfs_alloc_fixup_trees(cnt_cur, bno_cur, fbno, flen,
1422 rbno, rlen, XFSA_FIXUP_CNT_OK)))
1423 goto error0;
1424 xfs_btree_del_cursor(cnt_cur, XFS_BTREE_NOERROR);
1425 xfs_btree_del_cursor(bno_cur, XFS_BTREE_NOERROR);
1426 cnt_cur = bno_cur = NULL;
1427 args->len = rlen;
1428 args->agbno = rbno;
1429 XFS_WANT_CORRUPTED_GOTO(
1430 args->agbno + args->len <=
1431 be32_to_cpu(XFS_BUF_TO_AGF(args->agbp)->agf_length),
1432 error0);
1433 trace_xfs_alloc_size_done(args);
1434 return 0;
1435
1436error0:
1437 trace_xfs_alloc_size_error(args);
1438 if (cnt_cur)
1439 xfs_btree_del_cursor(cnt_cur, XFS_BTREE_ERROR);
1440 if (bno_cur)
1441 xfs_btree_del_cursor(bno_cur, XFS_BTREE_ERROR);
1442 return error;
1443
1444out_nominleft:
1445 xfs_btree_del_cursor(cnt_cur, XFS_BTREE_NOERROR);
1446 trace_xfs_alloc_size_nominleft(args);
1447 args->agbno = NULLAGBLOCK;
1448 return 0;
1449}
1450
1451/*
1452 * Deal with the case where only small freespaces remain.
1453 * Either return the contents of the last freespace record,
1454 * or allocate space from the freelist if there is nothing in the tree.
1455 */
1456STATIC int /* error */
1457xfs_alloc_ag_vextent_small(
1458 xfs_alloc_arg_t *args, /* allocation argument structure */
1459 xfs_btree_cur_t *ccur, /* by-size cursor */
1460 xfs_agblock_t *fbnop, /* result block number */
1461 xfs_extlen_t *flenp, /* result length */
1462 int *stat) /* status: 0-freelist, 1-normal/none */
1463{
1464 int error;
1465 xfs_agblock_t fbno;
1466 xfs_extlen_t flen;
1467 int i;
1468
1469 if ((error = xfs_btree_decrement(ccur, 0, &i)))
1470 goto error0;
1471 if (i) {
1472 if ((error = xfs_alloc_get_rec(ccur, &fbno, &flen, &i)))
1473 goto error0;
1474 XFS_WANT_CORRUPTED_GOTO(i == 1, error0);
1475 }
1476 /*
1477 * Nothing in the btree, try the freelist. Make sure
1478 * to respect minleft even when pulling from the
1479 * freelist.
1480 */
1481 else if (args->minlen == 1 && args->alignment == 1 && !args->isfl &&
1482 (be32_to_cpu(XFS_BUF_TO_AGF(args->agbp)->agf_flcount)
1483 > args->minleft)) {
1484 error = xfs_alloc_get_freelist(args->tp, args->agbp, &fbno, 0);
1485 if (error)
1486 goto error0;
1487 if (fbno != NULLAGBLOCK) {
1488 xfs_extent_busy_reuse(args->mp, args->agno, fbno, 1,
1489 args->userdata);
1490
1491 if (args->userdata) {
1492 xfs_buf_t *bp;
1493
1494 bp = xfs_btree_get_bufs(args->mp, args->tp,
1495 args->agno, fbno, 0);
1496 xfs_trans_binval(args->tp, bp);
1497 }
1498 args->len = 1;
1499 args->agbno = fbno;
1500 XFS_WANT_CORRUPTED_GOTO(
1501 args->agbno + args->len <=
1502 be32_to_cpu(XFS_BUF_TO_AGF(args->agbp)->agf_length),
1503 error0);
1504 args->wasfromfl = 1;
1505 trace_xfs_alloc_small_freelist(args);
1506 *stat = 0;
1507 return 0;
1508 }
1509 /*
1510 * Nothing in the freelist.
1511 */
1512 else
1513 flen = 0;
1514 }
1515 /*
1516 * Can't allocate from the freelist for some reason.
1517 */
1518 else {
1519 fbno = NULLAGBLOCK;
1520 flen = 0;
1521 }
1522 /*
1523 * Can't do the allocation, give up.
1524 */
1525 if (flen < args->minlen) {
1526 args->agbno = NULLAGBLOCK;
1527 trace_xfs_alloc_small_notenough(args);
1528 flen = 0;
1529 }
1530 *fbnop = fbno;
1531 *flenp = flen;
1532 *stat = 1;
1533 trace_xfs_alloc_small_done(args);
1534 return 0;
1535
1536error0:
1537 trace_xfs_alloc_small_error(args);
1538 return error;
1539}
1540
1541/*
1542 * Free the extent starting at agno/bno for length.
1543 */
1544STATIC int /* error */
1545xfs_free_ag_extent(
1546 xfs_trans_t *tp, /* transaction pointer */
1547 xfs_buf_t *agbp, /* buffer for a.g. freelist header */
1548 xfs_agnumber_t agno, /* allocation group number */
1549 xfs_agblock_t bno, /* starting block number */
1550 xfs_extlen_t len, /* length of extent */
1551 int isfl) /* set if is freelist blocks - no sb acctg */
1552{
1553 xfs_btree_cur_t *bno_cur; /* cursor for by-block btree */
1554 xfs_btree_cur_t *cnt_cur; /* cursor for by-size btree */
1555 int error; /* error return value */
1556 xfs_agblock_t gtbno; /* start of right neighbor block */
1557 xfs_extlen_t gtlen; /* length of right neighbor block */
1558 int haveleft; /* have a left neighbor block */
1559 int haveright; /* have a right neighbor block */
1560 int i; /* temp, result code */
1561 xfs_agblock_t ltbno; /* start of left neighbor block */
1562 xfs_extlen_t ltlen; /* length of left neighbor block */
1563 xfs_mount_t *mp; /* mount point struct for filesystem */
1564 xfs_agblock_t nbno; /* new starting block of freespace */
1565 xfs_extlen_t nlen; /* new length of freespace */
1566 xfs_perag_t *pag; /* per allocation group data */
1567
1568 mp = tp->t_mountp;
1569 /*
1570 * Allocate and initialize a cursor for the by-block btree.
1571 */
1572 bno_cur = xfs_allocbt_init_cursor(mp, tp, agbp, agno, XFS_BTNUM_BNO);
1573 cnt_cur = NULL;
1574 /*
1575 * Look for a neighboring block on the left (lower block numbers)
1576 * that is contiguous with this space.
1577 */
1578 if ((error = xfs_alloc_lookup_le(bno_cur, bno, len, &haveleft)))
1579 goto error0;
1580 if (haveleft) {
1581 /*
1582 * There is a block to our left.
1583 */
1584 if ((error = xfs_alloc_get_rec(bno_cur, <bno, <len, &i)))
1585 goto error0;
1586 XFS_WANT_CORRUPTED_GOTO(i == 1, error0);
1587 /*
1588 * It's not contiguous, though.
1589 */
1590 if (ltbno + ltlen < bno)
1591 haveleft = 0;
1592 else {
1593 /*
1594 * If this failure happens the request to free this
1595 * space was invalid, it's (partly) already free.
1596 * Very bad.
1597 */
1598 XFS_WANT_CORRUPTED_GOTO(ltbno + ltlen <= bno, error0);
1599 }
1600 }
1601 /*
1602 * Look for a neighboring block on the right (higher block numbers)
1603 * that is contiguous with this space.
1604 */
1605 if ((error = xfs_btree_increment(bno_cur, 0, &haveright)))
1606 goto error0;
1607 if (haveright) {
1608 /*
1609 * There is a block to our right.
1610 */
1611 if ((error = xfs_alloc_get_rec(bno_cur, >bno, >len, &i)))
1612 goto error0;
1613 XFS_WANT_CORRUPTED_GOTO(i == 1, error0);
1614 /*
1615 * It's not contiguous, though.
1616 */
1617 if (bno + len < gtbno)
1618 haveright = 0;
1619 else {
1620 /*
1621 * If this failure happens the request to free this
1622 * space was invalid, it's (partly) already free.
1623 * Very bad.
1624 */
1625 XFS_WANT_CORRUPTED_GOTO(gtbno >= bno + len, error0);
1626 }
1627 }
1628 /*
1629 * Now allocate and initialize a cursor for the by-size tree.
1630 */
1631 cnt_cur = xfs_allocbt_init_cursor(mp, tp, agbp, agno, XFS_BTNUM_CNT);
1632 /*
1633 * Have both left and right contiguous neighbors.
1634 * Merge all three into a single free block.
1635 */
1636 if (haveleft && haveright) {
1637 /*
1638 * Delete the old by-size entry on the left.
1639 */
1640 if ((error = xfs_alloc_lookup_eq(cnt_cur, ltbno, ltlen, &i)))
1641 goto error0;
1642 XFS_WANT_CORRUPTED_GOTO(i == 1, error0);
1643 if ((error = xfs_btree_delete(cnt_cur, &i)))
1644 goto error0;
1645 XFS_WANT_CORRUPTED_GOTO(i == 1, error0);
1646 /*
1647 * Delete the old by-size entry on the right.
1648 */
1649 if ((error = xfs_alloc_lookup_eq(cnt_cur, gtbno, gtlen, &i)))
1650 goto error0;
1651 XFS_WANT_CORRUPTED_GOTO(i == 1, error0);
1652 if ((error = xfs_btree_delete(cnt_cur, &i)))
1653 goto error0;
1654 XFS_WANT_CORRUPTED_GOTO(i == 1, error0);
1655 /*
1656 * Delete the old by-block entry for the right block.
1657 */
1658 if ((error = xfs_btree_delete(bno_cur, &i)))
1659 goto error0;
1660 XFS_WANT_CORRUPTED_GOTO(i == 1, error0);
1661 /*
1662 * Move the by-block cursor back to the left neighbor.
1663 */
1664 if ((error = xfs_btree_decrement(bno_cur, 0, &i)))
1665 goto error0;
1666 XFS_WANT_CORRUPTED_GOTO(i == 1, error0);
1667#ifdef DEBUG
1668 /*
1669 * Check that this is the right record: delete didn't
1670 * mangle the cursor.
1671 */
1672 {
1673 xfs_agblock_t xxbno;
1674 xfs_extlen_t xxlen;
1675
1676 if ((error = xfs_alloc_get_rec(bno_cur, &xxbno, &xxlen,
1677 &i)))
1678 goto error0;
1679 XFS_WANT_CORRUPTED_GOTO(
1680 i == 1 && xxbno == ltbno && xxlen == ltlen,
1681 error0);
1682 }
1683#endif
1684 /*
1685 * Update remaining by-block entry to the new, joined block.
1686 */
1687 nbno = ltbno;
1688 nlen = len + ltlen + gtlen;
1689 if ((error = xfs_alloc_update(bno_cur, nbno, nlen)))
1690 goto error0;
1691 }
1692 /*
1693 * Have only a left contiguous neighbor.
1694 * Merge it together with the new freespace.
1695 */
1696 else if (haveleft) {
1697 /*
1698 * Delete the old by-size entry on the left.
1699 */
1700 if ((error = xfs_alloc_lookup_eq(cnt_cur, ltbno, ltlen, &i)))
1701 goto error0;
1702 XFS_WANT_CORRUPTED_GOTO(i == 1, error0);
1703 if ((error = xfs_btree_delete(cnt_cur, &i)))
1704 goto error0;
1705 XFS_WANT_CORRUPTED_GOTO(i == 1, error0);
1706 /*
1707 * Back up the by-block cursor to the left neighbor, and
1708 * update its length.
1709 */
1710 if ((error = xfs_btree_decrement(bno_cur, 0, &i)))
1711 goto error0;
1712 XFS_WANT_CORRUPTED_GOTO(i == 1, error0);
1713 nbno = ltbno;
1714 nlen = len + ltlen;
1715 if ((error = xfs_alloc_update(bno_cur, nbno, nlen)))
1716 goto error0;
1717 }
1718 /*
1719 * Have only a right contiguous neighbor.
1720 * Merge it together with the new freespace.
1721 */
1722 else if (haveright) {
1723 /*
1724 * Delete the old by-size entry on the right.
1725 */
1726 if ((error = xfs_alloc_lookup_eq(cnt_cur, gtbno, gtlen, &i)))
1727 goto error0;
1728 XFS_WANT_CORRUPTED_GOTO(i == 1, error0);
1729 if ((error = xfs_btree_delete(cnt_cur, &i)))
1730 goto error0;
1731 XFS_WANT_CORRUPTED_GOTO(i == 1, error0);
1732 /*
1733 * Update the starting block and length of the right
1734 * neighbor in the by-block tree.
1735 */
1736 nbno = bno;
1737 nlen = len + gtlen;
1738 if ((error = xfs_alloc_update(bno_cur, nbno, nlen)))
1739 goto error0;
1740 }
1741 /*
1742 * No contiguous neighbors.
1743 * Insert the new freespace into the by-block tree.
1744 */
1745 else {
1746 nbno = bno;
1747 nlen = len;
1748 if ((error = xfs_btree_insert(bno_cur, &i)))
1749 goto error0;
1750 XFS_WANT_CORRUPTED_GOTO(i == 1, error0);
1751 }
1752 xfs_btree_del_cursor(bno_cur, XFS_BTREE_NOERROR);
1753 bno_cur = NULL;
1754 /*
1755 * In all cases we need to insert the new freespace in the by-size tree.
1756 */
1757 if ((error = xfs_alloc_lookup_eq(cnt_cur, nbno, nlen, &i)))
1758 goto error0;
1759 XFS_WANT_CORRUPTED_GOTO(i == 0, error0);
1760 if ((error = xfs_btree_insert(cnt_cur, &i)))
1761 goto error0;
1762 XFS_WANT_CORRUPTED_GOTO(i == 1, error0);
1763 xfs_btree_del_cursor(cnt_cur, XFS_BTREE_NOERROR);
1764 cnt_cur = NULL;
1765
1766 /*
1767 * Update the freespace totals in the ag and superblock.
1768 */
1769 pag = xfs_perag_get(mp, agno);
1770 error = xfs_alloc_update_counters(tp, pag, agbp, len);
1771 xfs_perag_put(pag);
1772 if (error)
1773 goto error0;
1774
1775 if (!isfl)
1776 xfs_trans_mod_sb(tp, XFS_TRANS_SB_FDBLOCKS, (long)len);
1777 XFS_STATS_INC(xs_freex);
1778 XFS_STATS_ADD(xs_freeb, len);
1779
1780 trace_xfs_free_extent(mp, agno, bno, len, isfl, haveleft, haveright);
1781
1782 return 0;
1783
1784 error0:
1785 trace_xfs_free_extent(mp, agno, bno, len, isfl, -1, -1);
1786 if (bno_cur)
1787 xfs_btree_del_cursor(bno_cur, XFS_BTREE_ERROR);
1788 if (cnt_cur)
1789 xfs_btree_del_cursor(cnt_cur, XFS_BTREE_ERROR);
1790 return error;
1791}
1792
1793/*
1794 * Visible (exported) allocation/free functions.
1795 * Some of these are used just by xfs_alloc_btree.c and this file.
1796 */
1797
1798/*
1799 * Compute and fill in value of m_ag_maxlevels.
1800 */
1801void
1802xfs_alloc_compute_maxlevels(
1803 xfs_mount_t *mp) /* file system mount structure */
1804{
1805 int level;
1806 uint maxblocks;
1807 uint maxleafents;
1808 int minleafrecs;
1809 int minnoderecs;
1810
1811 maxleafents = (mp->m_sb.sb_agblocks + 1) / 2;
1812 minleafrecs = mp->m_alloc_mnr[0];
1813 minnoderecs = mp->m_alloc_mnr[1];
1814 maxblocks = (maxleafents + minleafrecs - 1) / minleafrecs;
1815 for (level = 1; maxblocks > 1; level++)
1816 maxblocks = (maxblocks + minnoderecs - 1) / minnoderecs;
1817 mp->m_ag_maxlevels = level;
1818}
1819
1820/*
1821 * Find the length of the longest extent in an AG.
1822 */
1823xfs_extlen_t
1824xfs_alloc_longest_free_extent(
1825 struct xfs_mount *mp,
1826 struct xfs_perag *pag)
1827{
1828 xfs_extlen_t need, delta = 0;
1829
1830 need = XFS_MIN_FREELIST_PAG(pag, mp);
1831 if (need > pag->pagf_flcount)
1832 delta = need - pag->pagf_flcount;
1833
1834 if (pag->pagf_longest > delta)
1835 return pag->pagf_longest - delta;
1836 return pag->pagf_flcount > 0 || pag->pagf_longest > 0;
1837}
1838
1839/*
1840 * Decide whether to use this allocation group for this allocation.
1841 * If so, fix up the btree freelist's size.
1842 */
1843STATIC int /* error */
1844xfs_alloc_fix_freelist(
1845 xfs_alloc_arg_t *args, /* allocation argument structure */
1846 int flags) /* XFS_ALLOC_FLAG_... */
1847{
1848 xfs_buf_t *agbp; /* agf buffer pointer */
1849 xfs_agf_t *agf; /* a.g. freespace structure pointer */
1850 xfs_buf_t *agflbp;/* agfl buffer pointer */
1851 xfs_agblock_t bno; /* freelist block */
1852 xfs_extlen_t delta; /* new blocks needed in freelist */
1853 int error; /* error result code */
1854 xfs_extlen_t longest;/* longest extent in allocation group */
1855 xfs_mount_t *mp; /* file system mount point structure */
1856 xfs_extlen_t need; /* total blocks needed in freelist */
1857 xfs_perag_t *pag; /* per-ag information structure */
1858 xfs_alloc_arg_t targs; /* local allocation arguments */
1859 xfs_trans_t *tp; /* transaction pointer */
1860
1861 mp = args->mp;
1862
1863 pag = args->pag;
1864 tp = args->tp;
1865 if (!pag->pagf_init) {
1866 if ((error = xfs_alloc_read_agf(mp, tp, args->agno, flags,
1867 &agbp)))
1868 return error;
1869 if (!pag->pagf_init) {
1870 ASSERT(flags & XFS_ALLOC_FLAG_TRYLOCK);
1871 ASSERT(!(flags & XFS_ALLOC_FLAG_FREEING));
1872 args->agbp = NULL;
1873 return 0;
1874 }
1875 } else
1876 agbp = NULL;
1877
1878 /*
1879 * If this is a metadata preferred pag and we are user data
1880 * then try somewhere else if we are not being asked to
1881 * try harder at this point
1882 */
1883 if (pag->pagf_metadata && args->userdata &&
1884 (flags & XFS_ALLOC_FLAG_TRYLOCK)) {
1885 ASSERT(!(flags & XFS_ALLOC_FLAG_FREEING));
1886 args->agbp = NULL;
1887 return 0;
1888 }
1889
1890 if (!(flags & XFS_ALLOC_FLAG_FREEING)) {
1891 /*
1892 * If it looks like there isn't a long enough extent, or enough
1893 * total blocks, reject it.
1894 */
1895 need = XFS_MIN_FREELIST_PAG(pag, mp);
1896 longest = xfs_alloc_longest_free_extent(mp, pag);
1897 if ((args->minlen + args->alignment + args->minalignslop - 1) >
1898 longest ||
1899 ((int)(pag->pagf_freeblks + pag->pagf_flcount -
1900 need - args->total) < (int)args->minleft)) {
1901 if (agbp)
1902 xfs_trans_brelse(tp, agbp);
1903 args->agbp = NULL;
1904 return 0;
1905 }
1906 }
1907
1908 /*
1909 * Get the a.g. freespace buffer.
1910 * Can fail if we're not blocking on locks, and it's held.
1911 */
1912 if (agbp == NULL) {
1913 if ((error = xfs_alloc_read_agf(mp, tp, args->agno, flags,
1914 &agbp)))
1915 return error;
1916 if (agbp == NULL) {
1917 ASSERT(flags & XFS_ALLOC_FLAG_TRYLOCK);
1918 ASSERT(!(flags & XFS_ALLOC_FLAG_FREEING));
1919 args->agbp = NULL;
1920 return 0;
1921 }
1922 }
1923 /*
1924 * Figure out how many blocks we should have in the freelist.
1925 */
1926 agf = XFS_BUF_TO_AGF(agbp);
1927 need = XFS_MIN_FREELIST(agf, mp);
1928 /*
1929 * If there isn't enough total or single-extent, reject it.
1930 */
1931 if (!(flags & XFS_ALLOC_FLAG_FREEING)) {
1932 delta = need > be32_to_cpu(agf->agf_flcount) ?
1933 (need - be32_to_cpu(agf->agf_flcount)) : 0;
1934 longest = be32_to_cpu(agf->agf_longest);
1935 longest = (longest > delta) ? (longest - delta) :
1936 (be32_to_cpu(agf->agf_flcount) > 0 || longest > 0);
1937 if ((args->minlen + args->alignment + args->minalignslop - 1) >
1938 longest ||
1939 ((int)(be32_to_cpu(agf->agf_freeblks) +
1940 be32_to_cpu(agf->agf_flcount) - need - args->total) <
1941 (int)args->minleft)) {
1942 xfs_trans_brelse(tp, agbp);
1943 args->agbp = NULL;
1944 return 0;
1945 }
1946 }
1947 /*
1948 * Make the freelist shorter if it's too long.
1949 */
1950 while (be32_to_cpu(agf->agf_flcount) > need) {
1951 xfs_buf_t *bp;
1952
1953 error = xfs_alloc_get_freelist(tp, agbp, &bno, 0);
1954 if (error)
1955 return error;
1956 if ((error = xfs_free_ag_extent(tp, agbp, args->agno, bno, 1, 1)))
1957 return error;
1958 bp = xfs_btree_get_bufs(mp, tp, args->agno, bno, 0);
1959 xfs_trans_binval(tp, bp);
1960 }
1961 /*
1962 * Initialize the args structure.
1963 */
1964 memset(&targs, 0, sizeof(targs));
1965 targs.tp = tp;
1966 targs.mp = mp;
1967 targs.agbp = agbp;
1968 targs.agno = args->agno;
1969 targs.alignment = targs.minlen = targs.prod = targs.isfl = 1;
1970 targs.type = XFS_ALLOCTYPE_THIS_AG;
1971 targs.pag = pag;
1972 if ((error = xfs_alloc_read_agfl(mp, tp, targs.agno, &agflbp)))
1973 return error;
1974 /*
1975 * Make the freelist longer if it's too short.
1976 */
1977 while (be32_to_cpu(agf->agf_flcount) < need) {
1978 targs.agbno = 0;
1979 targs.maxlen = need - be32_to_cpu(agf->agf_flcount);
1980 /*
1981 * Allocate as many blocks as possible at once.
1982 */
1983 if ((error = xfs_alloc_ag_vextent(&targs))) {
1984 xfs_trans_brelse(tp, agflbp);
1985 return error;
1986 }
1987 /*
1988 * Stop if we run out. Won't happen if callers are obeying
1989 * the restrictions correctly. Can happen for free calls
1990 * on a completely full ag.
1991 */
1992 if (targs.agbno == NULLAGBLOCK) {
1993 if (flags & XFS_ALLOC_FLAG_FREEING)
1994 break;
1995 xfs_trans_brelse(tp, agflbp);
1996 args->agbp = NULL;
1997 return 0;
1998 }
1999 /*
2000 * Put each allocated block on the list.
2001 */
2002 for (bno = targs.agbno; bno < targs.agbno + targs.len; bno++) {
2003 error = xfs_alloc_put_freelist(tp, agbp,
2004 agflbp, bno, 0);
2005 if (error)
2006 return error;
2007 }
2008 }
2009 xfs_trans_brelse(tp, agflbp);
2010 args->agbp = agbp;
2011 return 0;
2012}
2013
2014/*
2015 * Get a block from the freelist.
2016 * Returns with the buffer for the block gotten.
2017 */
2018int /* error */
2019xfs_alloc_get_freelist(
2020 xfs_trans_t *tp, /* transaction pointer */
2021 xfs_buf_t *agbp, /* buffer containing the agf structure */
2022 xfs_agblock_t *bnop, /* block address retrieved from freelist */
2023 int btreeblk) /* destination is a AGF btree */
2024{
2025 xfs_agf_t *agf; /* a.g. freespace structure */
2026 xfs_buf_t *agflbp;/* buffer for a.g. freelist structure */
2027 xfs_agblock_t bno; /* block number returned */
2028 __be32 *agfl_bno;
2029 int error;
2030 int logflags;
2031 xfs_mount_t *mp = tp->t_mountp;
2032 xfs_perag_t *pag; /* per allocation group data */
2033
2034 /*
2035 * Freelist is empty, give up.
2036 */
2037 agf = XFS_BUF_TO_AGF(agbp);
2038 if (!agf->agf_flcount) {
2039 *bnop = NULLAGBLOCK;
2040 return 0;
2041 }
2042 /*
2043 * Read the array of free blocks.
2044 */
2045 error = xfs_alloc_read_agfl(mp, tp, be32_to_cpu(agf->agf_seqno),
2046 &agflbp);
2047 if (error)
2048 return error;
2049
2050
2051 /*
2052 * Get the block number and update the data structures.
2053 */
2054 agfl_bno = XFS_BUF_TO_AGFL_BNO(mp, agflbp);
2055 bno = be32_to_cpu(agfl_bno[be32_to_cpu(agf->agf_flfirst)]);
2056 be32_add_cpu(&agf->agf_flfirst, 1);
2057 xfs_trans_brelse(tp, agflbp);
2058 if (be32_to_cpu(agf->agf_flfirst) == XFS_AGFL_SIZE(mp))
2059 agf->agf_flfirst = 0;
2060
2061 pag = xfs_perag_get(mp, be32_to_cpu(agf->agf_seqno));
2062 be32_add_cpu(&agf->agf_flcount, -1);
2063 xfs_trans_agflist_delta(tp, -1);
2064 pag->pagf_flcount--;
2065 xfs_perag_put(pag);
2066
2067 logflags = XFS_AGF_FLFIRST | XFS_AGF_FLCOUNT;
2068 if (btreeblk) {
2069 be32_add_cpu(&agf->agf_btreeblks, 1);
2070 pag->pagf_btreeblks++;
2071 logflags |= XFS_AGF_BTREEBLKS;
2072 }
2073
2074 xfs_alloc_log_agf(tp, agbp, logflags);
2075 *bnop = bno;
2076
2077 return 0;
2078}
2079
2080/*
2081 * Log the given fields from the agf structure.
2082 */
2083void
2084xfs_alloc_log_agf(
2085 xfs_trans_t *tp, /* transaction pointer */
2086 xfs_buf_t *bp, /* buffer for a.g. freelist header */
2087 int fields) /* mask of fields to be logged (XFS_AGF_...) */
2088{
2089 int first; /* first byte offset */
2090 int last; /* last byte offset */
2091 static const short offsets[] = {
2092 offsetof(xfs_agf_t, agf_magicnum),
2093 offsetof(xfs_agf_t, agf_versionnum),
2094 offsetof(xfs_agf_t, agf_seqno),
2095 offsetof(xfs_agf_t, agf_length),
2096 offsetof(xfs_agf_t, agf_roots[0]),
2097 offsetof(xfs_agf_t, agf_levels[0]),
2098 offsetof(xfs_agf_t, agf_flfirst),
2099 offsetof(xfs_agf_t, agf_fllast),
2100 offsetof(xfs_agf_t, agf_flcount),
2101 offsetof(xfs_agf_t, agf_freeblks),
2102 offsetof(xfs_agf_t, agf_longest),
2103 offsetof(xfs_agf_t, agf_btreeblks),
2104 offsetof(xfs_agf_t, agf_uuid),
2105 sizeof(xfs_agf_t)
2106 };
2107
2108 trace_xfs_agf(tp->t_mountp, XFS_BUF_TO_AGF(bp), fields, _RET_IP_);
2109
2110 xfs_trans_buf_set_type(tp, bp, XFS_BLFT_AGF_BUF);
2111
2112 xfs_btree_offsets(fields, offsets, XFS_AGF_NUM_BITS, &first, &last);
2113 xfs_trans_log_buf(tp, bp, (uint)first, (uint)last);
2114}
2115
2116/*
2117 * Interface for inode allocation to force the pag data to be initialized.
2118 */
2119int /* error */
2120xfs_alloc_pagf_init(
2121 xfs_mount_t *mp, /* file system mount structure */
2122 xfs_trans_t *tp, /* transaction pointer */
2123 xfs_agnumber_t agno, /* allocation group number */
2124 int flags) /* XFS_ALLOC_FLAGS_... */
2125{
2126 xfs_buf_t *bp;
2127 int error;
2128
2129 if ((error = xfs_alloc_read_agf(mp, tp, agno, flags, &bp)))
2130 return error;
2131 if (bp)
2132 xfs_trans_brelse(tp, bp);
2133 return 0;
2134}
2135
2136/*
2137 * Put the block on the freelist for the allocation group.
2138 */
2139int /* error */
2140xfs_alloc_put_freelist(
2141 xfs_trans_t *tp, /* transaction pointer */
2142 xfs_buf_t *agbp, /* buffer for a.g. freelist header */
2143 xfs_buf_t *agflbp,/* buffer for a.g. free block array */
2144 xfs_agblock_t bno, /* block being freed */
2145 int btreeblk) /* block came from a AGF btree */
2146{
2147 xfs_agf_t *agf; /* a.g. freespace structure */
2148 __be32 *blockp;/* pointer to array entry */
2149 int error;
2150 int logflags;
2151 xfs_mount_t *mp; /* mount structure */
2152 xfs_perag_t *pag; /* per allocation group data */
2153 __be32 *agfl_bno;
2154 int startoff;
2155
2156 agf = XFS_BUF_TO_AGF(agbp);
2157 mp = tp->t_mountp;
2158
2159 if (!agflbp && (error = xfs_alloc_read_agfl(mp, tp,
2160 be32_to_cpu(agf->agf_seqno), &agflbp)))
2161 return error;
2162 be32_add_cpu(&agf->agf_fllast, 1);
2163 if (be32_to_cpu(agf->agf_fllast) == XFS_AGFL_SIZE(mp))
2164 agf->agf_fllast = 0;
2165
2166 pag = xfs_perag_get(mp, be32_to_cpu(agf->agf_seqno));
2167 be32_add_cpu(&agf->agf_flcount, 1);
2168 xfs_trans_agflist_delta(tp, 1);
2169 pag->pagf_flcount++;
2170
2171 logflags = XFS_AGF_FLLAST | XFS_AGF_FLCOUNT;
2172 if (btreeblk) {
2173 be32_add_cpu(&agf->agf_btreeblks, -1);
2174 pag->pagf_btreeblks--;
2175 logflags |= XFS_AGF_BTREEBLKS;
2176 }
2177 xfs_perag_put(pag);
2178
2179 xfs_alloc_log_agf(tp, agbp, logflags);
2180
2181 ASSERT(be32_to_cpu(agf->agf_flcount) <= XFS_AGFL_SIZE(mp));
2182
2183 agfl_bno = XFS_BUF_TO_AGFL_BNO(mp, agflbp);
2184 blockp = &agfl_bno[be32_to_cpu(agf->agf_fllast)];
2185 *blockp = cpu_to_be32(bno);
2186 startoff = (char *)blockp - (char *)agflbp->b_addr;
2187
2188 xfs_alloc_log_agf(tp, agbp, logflags);
2189
2190 xfs_trans_buf_set_type(tp, agflbp, XFS_BLFT_AGFL_BUF);
2191 xfs_trans_log_buf(tp, agflbp, startoff,
2192 startoff + sizeof(xfs_agblock_t) - 1);
2193 return 0;
2194}
2195
2196static bool
2197xfs_agf_verify(
2198 struct xfs_mount *mp,
2199 struct xfs_buf *bp)
2200 {
2201 struct xfs_agf *agf = XFS_BUF_TO_AGF(bp);
2202
2203 if (xfs_sb_version_hascrc(&mp->m_sb) &&
2204 !uuid_equal(&agf->agf_uuid, &mp->m_sb.sb_uuid))
2205 return false;
2206
2207 if (!(agf->agf_magicnum == cpu_to_be32(XFS_AGF_MAGIC) &&
2208 XFS_AGF_GOOD_VERSION(be32_to_cpu(agf->agf_versionnum)) &&
2209 be32_to_cpu(agf->agf_freeblks) <= be32_to_cpu(agf->agf_length) &&
2210 be32_to_cpu(agf->agf_flfirst) < XFS_AGFL_SIZE(mp) &&
2211 be32_to_cpu(agf->agf_fllast) < XFS_AGFL_SIZE(mp) &&
2212 be32_to_cpu(agf->agf_flcount) <= XFS_AGFL_SIZE(mp)))
2213 return false;
2214
2215 /*
2216 * during growfs operations, the perag is not fully initialised,
2217 * so we can't use it for any useful checking. growfs ensures we can't
2218 * use it by using uncached buffers that don't have the perag attached
2219 * so we can detect and avoid this problem.
2220 */
2221 if (bp->b_pag && be32_to_cpu(agf->agf_seqno) != bp->b_pag->pag_agno)
2222 return false;
2223
2224 if (xfs_sb_version_haslazysbcount(&mp->m_sb) &&
2225 be32_to_cpu(agf->agf_btreeblks) > be32_to_cpu(agf->agf_length))
2226 return false;
2227
2228 return true;;
2229
2230}
2231
2232static void
2233xfs_agf_read_verify(
2234 struct xfs_buf *bp)
2235{
2236 struct xfs_mount *mp = bp->b_target->bt_mount;
2237
2238 if (xfs_sb_version_hascrc(&mp->m_sb) &&
2239 !xfs_buf_verify_cksum(bp, XFS_AGF_CRC_OFF))
2240 xfs_buf_ioerror(bp, EFSBADCRC);
2241 else if (XFS_TEST_ERROR(!xfs_agf_verify(mp, bp), mp,
2242 XFS_ERRTAG_ALLOC_READ_AGF,
2243 XFS_RANDOM_ALLOC_READ_AGF))
2244 xfs_buf_ioerror(bp, EFSCORRUPTED);
2245
2246 if (bp->b_error)
2247 xfs_verifier_error(bp);
2248}
2249
2250static void
2251xfs_agf_write_verify(
2252 struct xfs_buf *bp)
2253{
2254 struct xfs_mount *mp = bp->b_target->bt_mount;
2255 struct xfs_buf_log_item *bip = bp->b_fspriv;
2256
2257 if (!xfs_agf_verify(mp, bp)) {
2258 xfs_buf_ioerror(bp, EFSCORRUPTED);
2259 xfs_verifier_error(bp);
2260 return;
2261 }
2262
2263 if (!xfs_sb_version_hascrc(&mp->m_sb))
2264 return;
2265
2266 if (bip)
2267 XFS_BUF_TO_AGF(bp)->agf_lsn = cpu_to_be64(bip->bli_item.li_lsn);
2268
2269 xfs_buf_update_cksum(bp, XFS_AGF_CRC_OFF);
2270}
2271
2272const struct xfs_buf_ops xfs_agf_buf_ops = {
2273 .verify_read = xfs_agf_read_verify,
2274 .verify_write = xfs_agf_write_verify,
2275};
2276
2277/*
2278 * Read in the allocation group header (free/alloc section).
2279 */
2280int /* error */
2281xfs_read_agf(
2282 struct xfs_mount *mp, /* mount point structure */
2283 struct xfs_trans *tp, /* transaction pointer */
2284 xfs_agnumber_t agno, /* allocation group number */
2285 int flags, /* XFS_BUF_ */
2286 struct xfs_buf **bpp) /* buffer for the ag freelist header */
2287{
2288 int error;
2289
2290 trace_xfs_read_agf(mp, agno);
2291
2292 ASSERT(agno != NULLAGNUMBER);
2293 error = xfs_trans_read_buf(
2294 mp, tp, mp->m_ddev_targp,
2295 XFS_AG_DADDR(mp, agno, XFS_AGF_DADDR(mp)),
2296 XFS_FSS_TO_BB(mp, 1), flags, bpp, &xfs_agf_buf_ops);
2297 if (error)
2298 return error;
2299 if (!*bpp)
2300 return 0;
2301
2302 ASSERT(!(*bpp)->b_error);
2303 xfs_buf_set_ref(*bpp, XFS_AGF_REF);
2304 return 0;
2305}
2306
2307/*
2308 * Read in the allocation group header (free/alloc section).
2309 */
2310int /* error */
2311xfs_alloc_read_agf(
2312 struct xfs_mount *mp, /* mount point structure */
2313 struct xfs_trans *tp, /* transaction pointer */
2314 xfs_agnumber_t agno, /* allocation group number */
2315 int flags, /* XFS_ALLOC_FLAG_... */
2316 struct xfs_buf **bpp) /* buffer for the ag freelist header */
2317{
2318 struct xfs_agf *agf; /* ag freelist header */
2319 struct xfs_perag *pag; /* per allocation group data */
2320 int error;
2321
2322 trace_xfs_alloc_read_agf(mp, agno);
2323
2324 ASSERT(agno != NULLAGNUMBER);
2325 error = xfs_read_agf(mp, tp, agno,
2326 (flags & XFS_ALLOC_FLAG_TRYLOCK) ? XBF_TRYLOCK : 0,
2327 bpp);
2328 if (error)
2329 return error;
2330 if (!*bpp)
2331 return 0;
2332 ASSERT(!(*bpp)->b_error);
2333
2334 agf = XFS_BUF_TO_AGF(*bpp);
2335 pag = xfs_perag_get(mp, agno);
2336 if (!pag->pagf_init) {
2337 pag->pagf_freeblks = be32_to_cpu(agf->agf_freeblks);
2338 pag->pagf_btreeblks = be32_to_cpu(agf->agf_btreeblks);
2339 pag->pagf_flcount = be32_to_cpu(agf->agf_flcount);
2340 pag->pagf_longest = be32_to_cpu(agf->agf_longest);
2341 pag->pagf_levels[XFS_BTNUM_BNOi] =
2342 be32_to_cpu(agf->agf_levels[XFS_BTNUM_BNOi]);
2343 pag->pagf_levels[XFS_BTNUM_CNTi] =
2344 be32_to_cpu(agf->agf_levels[XFS_BTNUM_CNTi]);
2345 spin_lock_init(&pag->pagb_lock);
2346 pag->pagb_count = 0;
2347 pag->pagb_tree = RB_ROOT;
2348 pag->pagf_init = 1;
2349 }
2350#ifdef DEBUG
2351 else if (!XFS_FORCED_SHUTDOWN(mp)) {
2352 ASSERT(pag->pagf_freeblks == be32_to_cpu(agf->agf_freeblks));
2353 ASSERT(pag->pagf_btreeblks == be32_to_cpu(agf->agf_btreeblks));
2354 ASSERT(pag->pagf_flcount == be32_to_cpu(agf->agf_flcount));
2355 ASSERT(pag->pagf_longest == be32_to_cpu(agf->agf_longest));
2356 ASSERT(pag->pagf_levels[XFS_BTNUM_BNOi] ==
2357 be32_to_cpu(agf->agf_levels[XFS_BTNUM_BNOi]));
2358 ASSERT(pag->pagf_levels[XFS_BTNUM_CNTi] ==
2359 be32_to_cpu(agf->agf_levels[XFS_BTNUM_CNTi]));
2360 }
2361#endif
2362 xfs_perag_put(pag);
2363 return 0;
2364}
2365
2366/*
2367 * Allocate an extent (variable-size).
2368 * Depending on the allocation type, we either look in a single allocation
2369 * group or loop over the allocation groups to find the result.
2370 */
2371int /* error */
2372xfs_alloc_vextent(
2373 xfs_alloc_arg_t *args) /* allocation argument structure */
2374{
2375 xfs_agblock_t agsize; /* allocation group size */
2376 int error;
2377 int flags; /* XFS_ALLOC_FLAG_... locking flags */
2378 xfs_extlen_t minleft;/* minimum left value, temp copy */
2379 xfs_mount_t *mp; /* mount structure pointer */
2380 xfs_agnumber_t sagno; /* starting allocation group number */
2381 xfs_alloctype_t type; /* input allocation type */
2382 int bump_rotor = 0;
2383 int no_min = 0;
2384 xfs_agnumber_t rotorstep = xfs_rotorstep; /* inode32 agf stepper */
2385
2386 mp = args->mp;
2387 type = args->otype = args->type;
2388 args->agbno = NULLAGBLOCK;
2389 /*
2390 * Just fix this up, for the case where the last a.g. is shorter
2391 * (or there's only one a.g.) and the caller couldn't easily figure
2392 * that out (xfs_bmap_alloc).
2393 */
2394 agsize = mp->m_sb.sb_agblocks;
2395 if (args->maxlen > agsize)
2396 args->maxlen = agsize;
2397 if (args->alignment == 0)
2398 args->alignment = 1;
2399 ASSERT(XFS_FSB_TO_AGNO(mp, args->fsbno) < mp->m_sb.sb_agcount);
2400 ASSERT(XFS_FSB_TO_AGBNO(mp, args->fsbno) < agsize);
2401 ASSERT(args->minlen <= args->maxlen);
2402 ASSERT(args->minlen <= agsize);
2403 ASSERT(args->mod < args->prod);
2404 if (XFS_FSB_TO_AGNO(mp, args->fsbno) >= mp->m_sb.sb_agcount ||
2405 XFS_FSB_TO_AGBNO(mp, args->fsbno) >= agsize ||
2406 args->minlen > args->maxlen || args->minlen > agsize ||
2407 args->mod >= args->prod) {
2408 args->fsbno = NULLFSBLOCK;
2409 trace_xfs_alloc_vextent_badargs(args);
2410 return 0;
2411 }
2412 minleft = args->minleft;
2413
2414 switch (type) {
2415 case XFS_ALLOCTYPE_THIS_AG:
2416 case XFS_ALLOCTYPE_NEAR_BNO:
2417 case XFS_ALLOCTYPE_THIS_BNO:
2418 /*
2419 * These three force us into a single a.g.
2420 */
2421 args->agno = XFS_FSB_TO_AGNO(mp, args->fsbno);
2422 args->pag = xfs_perag_get(mp, args->agno);
2423 args->minleft = 0;
2424 error = xfs_alloc_fix_freelist(args, 0);
2425 args->minleft = minleft;
2426 if (error) {
2427 trace_xfs_alloc_vextent_nofix(args);
2428 goto error0;
2429 }
2430 if (!args->agbp) {
2431 trace_xfs_alloc_vextent_noagbp(args);
2432 break;
2433 }
2434 args->agbno = XFS_FSB_TO_AGBNO(mp, args->fsbno);
2435 if ((error = xfs_alloc_ag_vextent(args)))
2436 goto error0;
2437 break;
2438 case XFS_ALLOCTYPE_START_BNO:
2439 /*
2440 * Try near allocation first, then anywhere-in-ag after
2441 * the first a.g. fails.
2442 */
2443 if ((args->userdata == XFS_ALLOC_INITIAL_USER_DATA) &&
2444 (mp->m_flags & XFS_MOUNT_32BITINODES)) {
2445 args->fsbno = XFS_AGB_TO_FSB(mp,
2446 ((mp->m_agfrotor / rotorstep) %
2447 mp->m_sb.sb_agcount), 0);
2448 bump_rotor = 1;
2449 }
2450 args->agbno = XFS_FSB_TO_AGBNO(mp, args->fsbno);
2451 args->type = XFS_ALLOCTYPE_NEAR_BNO;
2452 /* FALLTHROUGH */
2453 case XFS_ALLOCTYPE_ANY_AG:
2454 case XFS_ALLOCTYPE_START_AG:
2455 case XFS_ALLOCTYPE_FIRST_AG:
2456 /*
2457 * Rotate through the allocation groups looking for a winner.
2458 */
2459 if (type == XFS_ALLOCTYPE_ANY_AG) {
2460 /*
2461 * Start with the last place we left off.
2462 */
2463 args->agno = sagno = (mp->m_agfrotor / rotorstep) %
2464 mp->m_sb.sb_agcount;
2465 args->type = XFS_ALLOCTYPE_THIS_AG;
2466 flags = XFS_ALLOC_FLAG_TRYLOCK;
2467 } else if (type == XFS_ALLOCTYPE_FIRST_AG) {
2468 /*
2469 * Start with allocation group given by bno.
2470 */
2471 args->agno = XFS_FSB_TO_AGNO(mp, args->fsbno);
2472 args->type = XFS_ALLOCTYPE_THIS_AG;
2473 sagno = 0;
2474 flags = 0;
2475 } else {
2476 if (type == XFS_ALLOCTYPE_START_AG)
2477 args->type = XFS_ALLOCTYPE_THIS_AG;
2478 /*
2479 * Start with the given allocation group.
2480 */
2481 args->agno = sagno = XFS_FSB_TO_AGNO(mp, args->fsbno);
2482 flags = XFS_ALLOC_FLAG_TRYLOCK;
2483 }
2484 /*
2485 * Loop over allocation groups twice; first time with
2486 * trylock set, second time without.
2487 */
2488 for (;;) {
2489 args->pag = xfs_perag_get(mp, args->agno);
2490 if (no_min) args->minleft = 0;
2491 error = xfs_alloc_fix_freelist(args, flags);
2492 args->minleft = minleft;
2493 if (error) {
2494 trace_xfs_alloc_vextent_nofix(args);
2495 goto error0;
2496 }
2497 /*
2498 * If we get a buffer back then the allocation will fly.
2499 */
2500 if (args->agbp) {
2501 if ((error = xfs_alloc_ag_vextent(args)))
2502 goto error0;
2503 break;
2504 }
2505
2506 trace_xfs_alloc_vextent_loopfailed(args);
2507
2508 /*
2509 * Didn't work, figure out the next iteration.
2510 */
2511 if (args->agno == sagno &&
2512 type == XFS_ALLOCTYPE_START_BNO)
2513 args->type = XFS_ALLOCTYPE_THIS_AG;
2514 /*
2515 * For the first allocation, we can try any AG to get
2516 * space. However, if we already have allocated a
2517 * block, we don't want to try AGs whose number is below
2518 * sagno. Otherwise, we may end up with out-of-order
2519 * locking of AGF, which might cause deadlock.
2520 */
2521 if (++(args->agno) == mp->m_sb.sb_agcount) {
2522 if (args->firstblock != NULLFSBLOCK)
2523 args->agno = sagno;
2524 else
2525 args->agno = 0;
2526 }
2527 /*
2528 * Reached the starting a.g., must either be done
2529 * or switch to non-trylock mode.
2530 */
2531 if (args->agno == sagno) {
2532 if (no_min == 1) {
2533 args->agbno = NULLAGBLOCK;
2534 trace_xfs_alloc_vextent_allfailed(args);
2535 break;
2536 }
2537 if (flags == 0) {
2538 no_min = 1;
2539 } else {
2540 flags = 0;
2541 if (type == XFS_ALLOCTYPE_START_BNO) {
2542 args->agbno = XFS_FSB_TO_AGBNO(mp,
2543 args->fsbno);
2544 args->type = XFS_ALLOCTYPE_NEAR_BNO;
2545 }
2546 }
2547 }
2548 xfs_perag_put(args->pag);
2549 }
2550 if (bump_rotor || (type == XFS_ALLOCTYPE_ANY_AG)) {
2551 if (args->agno == sagno)
2552 mp->m_agfrotor = (mp->m_agfrotor + 1) %
2553 (mp->m_sb.sb_agcount * rotorstep);
2554 else
2555 mp->m_agfrotor = (args->agno * rotorstep + 1) %
2556 (mp->m_sb.sb_agcount * rotorstep);
2557 }
2558 break;
2559 default:
2560 ASSERT(0);
2561 /* NOTREACHED */
2562 }
2563 if (args->agbno == NULLAGBLOCK)
2564 args->fsbno = NULLFSBLOCK;
2565 else {
2566 args->fsbno = XFS_AGB_TO_FSB(mp, args->agno, args->agbno);
2567#ifdef DEBUG
2568 ASSERT(args->len >= args->minlen);
2569 ASSERT(args->len <= args->maxlen);
2570 ASSERT(args->agbno % args->alignment == 0);
2571 XFS_AG_CHECK_DADDR(mp, XFS_FSB_TO_DADDR(mp, args->fsbno),
2572 args->len);
2573#endif
2574 }
2575 xfs_perag_put(args->pag);
2576 return 0;
2577error0:
2578 xfs_perag_put(args->pag);
2579 return error;
2580}
2581
2582/*
2583 * Free an extent.
2584 * Just break up the extent address and hand off to xfs_free_ag_extent
2585 * after fixing up the freelist.
2586 */
2587int /* error */
2588xfs_free_extent(
2589 xfs_trans_t *tp, /* transaction pointer */
2590 xfs_fsblock_t bno, /* starting block number of extent */
2591 xfs_extlen_t len) /* length of extent */
2592{
2593 xfs_alloc_arg_t args;
2594 int error;
2595
2596 ASSERT(len != 0);
2597 memset(&args, 0, sizeof(xfs_alloc_arg_t));
2598 args.tp = tp;
2599 args.mp = tp->t_mountp;
2600
2601 /*
2602 * validate that the block number is legal - the enables us to detect
2603 * and handle a silent filesystem corruption rather than crashing.
2604 */
2605 args.agno = XFS_FSB_TO_AGNO(args.mp, bno);
2606 if (args.agno >= args.mp->m_sb.sb_agcount)
2607 return EFSCORRUPTED;
2608
2609 args.agbno = XFS_FSB_TO_AGBNO(args.mp, bno);
2610 if (args.agbno >= args.mp->m_sb.sb_agblocks)
2611 return EFSCORRUPTED;
2612
2613 args.pag = xfs_perag_get(args.mp, args.agno);
2614 ASSERT(args.pag);
2615
2616 error = xfs_alloc_fix_freelist(&args, XFS_ALLOC_FLAG_FREEING);
2617 if (error)
2618 goto error0;
2619
2620 /* validate the extent size is legal now we have the agf locked */
2621 if (args.agbno + len >
2622 be32_to_cpu(XFS_BUF_TO_AGF(args.agbp)->agf_length)) {
2623 error = EFSCORRUPTED;
2624 goto error0;
2625 }
2626
2627 error = xfs_free_ag_extent(tp, args.agbp, args.agno, args.agbno, len, 0);
2628 if (!error)
2629 xfs_extent_busy_insert(tp, args.agno, args.agbno, len, 0);
2630error0:
2631 xfs_perag_put(args.pag);
2632 return error;
2633}