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xfs_ialloc.c
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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_ialloc.h"
35 #include "xfs_alloc.h"
36 #include "xfs_rtalloc.h"
37 #include "xfs_error.h"
38 #include "xfs_bmap.h"
39 
40 
41 /*
42  * Allocation group level functions.
43  */
44 static inline int
45 xfs_ialloc_cluster_alignment(
46  xfs_alloc_arg_t *args)
47 {
48  if (xfs_sb_version_hasalign(&args->mp->m_sb) &&
49  args->mp->m_sb.sb_inoalignmt >=
51  return args->mp->m_sb.sb_inoalignmt;
52  return 1;
53 }
54 
55 /*
56  * Lookup a record by ino in the btree given by cur.
57  */
58 int /* error */
60  struct xfs_btree_cur *cur, /* btree cursor */
61  xfs_agino_t ino, /* starting inode of chunk */
62  xfs_lookup_t dir, /* <=, >=, == */
63  int *stat) /* success/failure */
64 {
65  cur->bc_rec.i.ir_startino = ino;
66  cur->bc_rec.i.ir_freecount = 0;
67  cur->bc_rec.i.ir_free = 0;
68  return xfs_btree_lookup(cur, dir, stat);
69 }
70 
71 /*
72  * Update the record referred to by cur to the value given.
73  * This either works (return 0) or gets an EFSCORRUPTED error.
74  */
75 STATIC int /* error */
77  struct xfs_btree_cur *cur, /* btree cursor */
78  xfs_inobt_rec_incore_t *irec) /* btree record */
79 {
80  union xfs_btree_rec rec;
81 
84  rec.inobt.ir_free = cpu_to_be64(irec->ir_free);
85  return xfs_btree_update(cur, &rec);
86 }
87 
88 /*
89  * Get the data from the pointed-to record.
90  */
91 int /* error */
93  struct xfs_btree_cur *cur, /* btree cursor */
94  xfs_inobt_rec_incore_t *irec, /* btree record */
95  int *stat) /* output: success/failure */
96 {
97  union xfs_btree_rec *rec;
98  int error;
99 
100  error = xfs_btree_get_rec(cur, &rec, stat);
101  if (!error && *stat == 1) {
104  irec->ir_free = be64_to_cpu(rec->inobt.ir_free);
105  }
106  return error;
107 }
108 
109 /*
110  * Verify that the number of free inodes in the AGI is correct.
111  */
112 #ifdef DEBUG
113 STATIC int
115  struct xfs_btree_cur *cur,
116  struct xfs_agi *agi)
117 {
118  if (cur->bc_nlevels == 1) {
120  int freecount = 0;
121  int error;
122  int i;
123 
124  error = xfs_inobt_lookup(cur, 0, XFS_LOOKUP_GE, &i);
125  if (error)
126  return error;
127 
128  do {
129  error = xfs_inobt_get_rec(cur, &rec, &i);
130  if (error)
131  return error;
132 
133  if (i) {
134  freecount += rec.ir_freecount;
135  error = xfs_btree_increment(cur, 0, &i);
136  if (error)
137  return error;
138  }
139  } while (i == 1);
140 
141  if (!XFS_FORCED_SHUTDOWN(cur->bc_mp))
142  ASSERT(freecount == be32_to_cpu(agi->agi_freecount));
143  }
144  return 0;
145 }
146 #else
147 #define xfs_check_agi_freecount(cur, agi) 0
148 #endif
149 
150 /*
151  * Initialise a new set of inodes.
152  */
153 STATIC int
155  struct xfs_mount *mp,
156  struct xfs_trans *tp,
157  xfs_agnumber_t agno,
158  xfs_agblock_t agbno,
160  unsigned int gen)
161 {
162  struct xfs_buf *fbuf;
163  struct xfs_dinode *free;
164  int blks_per_cluster, nbufs, ninodes;
165  int version;
166  int i, j;
167  xfs_daddr_t d;
168 
169  /*
170  * Loop over the new block(s), filling in the inodes.
171  * For small block sizes, manipulate the inodes in buffers
172  * which are multiples of the blocks size.
173  */
174  if (mp->m_sb.sb_blocksize >= XFS_INODE_CLUSTER_SIZE(mp)) {
175  blks_per_cluster = 1;
176  nbufs = length;
177  ninodes = mp->m_sb.sb_inopblock;
178  } else {
179  blks_per_cluster = XFS_INODE_CLUSTER_SIZE(mp) /
180  mp->m_sb.sb_blocksize;
181  nbufs = length / blks_per_cluster;
182  ninodes = blks_per_cluster * mp->m_sb.sb_inopblock;
183  }
184 
185  /*
186  * Figure out what version number to use in the inodes we create.
187  * If the superblock version has caught up to the one that supports
188  * the new inode format, then use the new inode version. Otherwise
189  * use the old version so that old kernels will continue to be
190  * able to use the file system.
191  */
192  if (xfs_sb_version_hasnlink(&mp->m_sb))
193  version = 2;
194  else
195  version = 1;
196 
197  for (j = 0; j < nbufs; j++) {
198  /*
199  * Get the block.
200  */
201  d = XFS_AGB_TO_DADDR(mp, agno, agbno + (j * blks_per_cluster));
202  fbuf = xfs_trans_get_buf(tp, mp->m_ddev_targp, d,
203  mp->m_bsize * blks_per_cluster, 0);
204  if (!fbuf)
205  return ENOMEM;
206  /*
207  * Initialize all inodes in this buffer and then log them.
208  *
209  * XXX: It would be much better if we had just one transaction
210  * to log a whole cluster of inodes instead of all the
211  * individual transactions causing a lot of log traffic.
212  */
213  xfs_buf_zero(fbuf, 0, ninodes << mp->m_sb.sb_inodelog);
214  for (i = 0; i < ninodes; i++) {
215  int ioffset = i << mp->m_sb.sb_inodelog;
216  uint isize = sizeof(struct xfs_dinode);
217 
218  free = xfs_make_iptr(mp, fbuf, i);
220  free->di_version = version;
221  free->di_gen = cpu_to_be32(gen);
223  xfs_trans_log_buf(tp, fbuf, ioffset, ioffset + isize - 1);
224  }
225  xfs_trans_inode_alloc_buf(tp, fbuf);
226  }
227  return 0;
228 }
229 
230 /*
231  * Allocate new inodes in the allocation group specified by agbp.
232  * Return 0 for success, else error code.
233  */
234 STATIC int /* error code or 0 */
236  xfs_trans_t *tp, /* transaction pointer */
237  xfs_buf_t *agbp, /* alloc group buffer */
238  int *alloc)
239 {
240  xfs_agi_t *agi; /* allocation group header */
241  xfs_alloc_arg_t args; /* allocation argument structure */
242  xfs_btree_cur_t *cur; /* inode btree cursor */
243  xfs_agnumber_t agno;
244  int error;
245  int i;
246  xfs_agino_t newino; /* new first inode's number */
247  xfs_agino_t newlen; /* new number of inodes */
248  xfs_agino_t thisino; /* current inode number, for loop */
249  int isaligned = 0; /* inode allocation at stripe unit */
250  /* boundary */
251  struct xfs_perag *pag;
252 
253  memset(&args, 0, sizeof(args));
254  args.tp = tp;
255  args.mp = tp->t_mountp;
256 
257  /*
258  * Locking will ensure that we don't have two callers in here
259  * at one time.
260  */
261  newlen = XFS_IALLOC_INODES(args.mp);
262  if (args.mp->m_maxicount &&
263  args.mp->m_sb.sb_icount + newlen > args.mp->m_maxicount)
264  return XFS_ERROR(ENOSPC);
265  args.minlen = args.maxlen = XFS_IALLOC_BLOCKS(args.mp);
266  /*
267  * First try to allocate inodes contiguous with the last-allocated
268  * chunk of inodes. If the filesystem is striped, this will fill
269  * an entire stripe unit with inodes.
270  */
271  agi = XFS_BUF_TO_AGI(agbp);
272  newino = be32_to_cpu(agi->agi_newino);
273  agno = be32_to_cpu(agi->agi_seqno);
274  args.agbno = XFS_AGINO_TO_AGBNO(args.mp, newino) +
275  XFS_IALLOC_BLOCKS(args.mp);
276  if (likely(newino != NULLAGINO &&
277  (args.agbno < be32_to_cpu(agi->agi_length)))) {
278  args.fsbno = XFS_AGB_TO_FSB(args.mp, agno, args.agbno);
280  args.mod = args.total = args.wasdel = args.isfl =
281  args.userdata = args.minalignslop = 0;
282  args.prod = 1;
283 
284  /*
285  * We need to take into account alignment here to ensure that
286  * we don't modify the free list if we fail to have an exact
287  * block. If we don't have an exact match, and every oher
288  * attempt allocation attempt fails, we'll end up cancelling
289  * a dirty transaction and shutting down.
290  *
291  * For an exact allocation, alignment must be 1,
292  * however we need to take cluster alignment into account when
293  * fixing up the freelist. Use the minalignslop field to
294  * indicate that extra blocks might be required for alignment,
295  * but not to use them in the actual exact allocation.
296  */
297  args.alignment = 1;
298  args.minalignslop = xfs_ialloc_cluster_alignment(&args) - 1;
299 
300  /* Allow space for the inode btree to split. */
301  args.minleft = args.mp->m_in_maxlevels - 1;
302  if ((error = xfs_alloc_vextent(&args)))
303  return error;
304  } else
305  args.fsbno = NULLFSBLOCK;
306 
307  if (unlikely(args.fsbno == NULLFSBLOCK)) {
308  /*
309  * Set the alignment for the allocation.
310  * If stripe alignment is turned on then align at stripe unit
311  * boundary.
312  * If the cluster size is smaller than a filesystem block
313  * then we're doing I/O for inodes in filesystem block size
314  * pieces, so don't need alignment anyway.
315  */
316  isaligned = 0;
317  if (args.mp->m_sinoalign) {
318  ASSERT(!(args.mp->m_flags & XFS_MOUNT_NOALIGN));
319  args.alignment = args.mp->m_dalign;
320  isaligned = 1;
321  } else
322  args.alignment = xfs_ialloc_cluster_alignment(&args);
323  /*
324  * Need to figure out where to allocate the inode blocks.
325  * Ideally they should be spaced out through the a.g.
326  * For now, just allocate blocks up front.
327  */
328  args.agbno = be32_to_cpu(agi->agi_root);
329  args.fsbno = XFS_AGB_TO_FSB(args.mp, agno, args.agbno);
330  /*
331  * Allocate a fixed-size extent of inodes.
332  */
334  args.mod = args.total = args.wasdel = args.isfl =
335  args.userdata = args.minalignslop = 0;
336  args.prod = 1;
337  /*
338  * Allow space for the inode btree to split.
339  */
340  args.minleft = args.mp->m_in_maxlevels - 1;
341  if ((error = xfs_alloc_vextent(&args)))
342  return error;
343  }
344 
345  /*
346  * If stripe alignment is turned on, then try again with cluster
347  * alignment.
348  */
349  if (isaligned && args.fsbno == NULLFSBLOCK) {
351  args.agbno = be32_to_cpu(agi->agi_root);
352  args.fsbno = XFS_AGB_TO_FSB(args.mp, agno, args.agbno);
353  args.alignment = xfs_ialloc_cluster_alignment(&args);
354  if ((error = xfs_alloc_vextent(&args)))
355  return error;
356  }
357 
358  if (args.fsbno == NULLFSBLOCK) {
359  *alloc = 0;
360  return 0;
361  }
362  ASSERT(args.len == args.minlen);
363 
364  /*
365  * Stamp and write the inode buffers.
366  *
367  * Seed the new inode cluster with a random generation number. This
368  * prevents short-term reuse of generation numbers if a chunk is
369  * freed and then immediately reallocated. We use random numbers
370  * rather than a linear progression to prevent the next generation
371  * number from being easily guessable.
372  */
373  error = xfs_ialloc_inode_init(args.mp, tp, agno, args.agbno,
374  args.len, random32());
375 
376  if (error)
377  return error;
378  /*
379  * Convert the results.
380  */
381  newino = XFS_OFFBNO_TO_AGINO(args.mp, args.agbno, 0);
382  be32_add_cpu(&agi->agi_count, newlen);
383  be32_add_cpu(&agi->agi_freecount, newlen);
384  pag = xfs_perag_get(args.mp, agno);
385  pag->pagi_freecount += newlen;
386  xfs_perag_put(pag);
387  agi->agi_newino = cpu_to_be32(newino);
388 
389  /*
390  * Insert records describing the new inode chunk into the btree.
391  */
392  cur = xfs_inobt_init_cursor(args.mp, tp, agbp, agno);
393  for (thisino = newino;
394  thisino < newino + newlen;
395  thisino += XFS_INODES_PER_CHUNK) {
396  cur->bc_rec.i.ir_startino = thisino;
399  error = xfs_btree_lookup(cur, XFS_LOOKUP_EQ, &i);
400  if (error) {
402  return error;
403  }
404  ASSERT(i == 0);
405  error = xfs_btree_insert(cur, &i);
406  if (error) {
408  return error;
409  }
410  ASSERT(i == 1);
411  }
413  /*
414  * Log allocation group header fields
415  */
416  xfs_ialloc_log_agi(tp, agbp,
418  /*
419  * Modify/log superblock values for inode count and inode free count.
420  */
421  xfs_trans_mod_sb(tp, XFS_TRANS_SB_ICOUNT, (long)newlen);
422  xfs_trans_mod_sb(tp, XFS_TRANS_SB_IFREE, (long)newlen);
423  *alloc = 1;
424  return 0;
425 }
426 
429  xfs_mount_t *mp)
430 {
431  xfs_agnumber_t agno;
432 
433  spin_lock(&mp->m_agirotor_lock);
434  agno = mp->m_agirotor;
435  if (++mp->m_agirotor >= mp->m_maxagi)
436  mp->m_agirotor = 0;
437  spin_unlock(&mp->m_agirotor_lock);
438 
439  return agno;
440 }
441 
442 /*
443  * Select an allocation group to look for a free inode in, based on the parent
444  * inode and then mode. Return the allocation group buffer.
445  */
448  xfs_trans_t *tp, /* transaction pointer */
449  xfs_ino_t parent, /* parent directory inode number */
450  umode_t mode, /* bits set to indicate file type */
451  int okalloc) /* ok to allocate more space */
452 {
453  xfs_agnumber_t agcount; /* number of ag's in the filesystem */
454  xfs_agnumber_t agno; /* current ag number */
455  int flags; /* alloc buffer locking flags */
456  xfs_extlen_t ineed; /* blocks needed for inode allocation */
457  xfs_extlen_t longest = 0; /* longest extent available */
458  xfs_mount_t *mp; /* mount point structure */
459  int needspace; /* file mode implies space allocated */
460  xfs_perag_t *pag; /* per allocation group data */
461  xfs_agnumber_t pagno; /* parent (starting) ag number */
462  int error;
463 
464  /*
465  * Files of these types need at least one block if length > 0
466  * (and they won't fit in the inode, but that's hard to figure out).
467  */
468  needspace = S_ISDIR(mode) || S_ISREG(mode) || S_ISLNK(mode);
469  mp = tp->t_mountp;
470  agcount = mp->m_maxagi;
471  if (S_ISDIR(mode))
472  pagno = xfs_ialloc_next_ag(mp);
473  else {
474  pagno = XFS_INO_TO_AGNO(mp, parent);
475  if (pagno >= agcount)
476  pagno = 0;
477  }
478 
479  ASSERT(pagno < agcount);
480 
481  /*
482  * Loop through allocation groups, looking for one with a little
483  * free space in it. Note we don't look for free inodes, exactly.
484  * Instead, we include whether there is a need to allocate inodes
485  * to mean that blocks must be allocated for them,
486  * if none are currently free.
487  */
488  agno = pagno;
489  flags = XFS_ALLOC_FLAG_TRYLOCK;
490  for (;;) {
491  pag = xfs_perag_get(mp, agno);
492  if (!pag->pagi_inodeok) {
493  xfs_ialloc_next_ag(mp);
494  goto nextag;
495  }
496 
497  if (!pag->pagi_init) {
498  error = xfs_ialloc_pagi_init(mp, tp, agno);
499  if (error)
500  goto nextag;
501  }
502 
503  if (pag->pagi_freecount) {
504  xfs_perag_put(pag);
505  return agno;
506  }
507 
508  if (!okalloc)
509  goto nextag;
510 
511  if (!pag->pagf_init) {
512  error = xfs_alloc_pagf_init(mp, tp, agno, flags);
513  if (error)
514  goto nextag;
515  }
516 
517  /*
518  * Is there enough free space for the file plus a block of
519  * inodes? (if we need to allocate some)?
520  */
521  ineed = XFS_IALLOC_BLOCKS(mp);
522  longest = pag->pagf_longest;
523  if (!longest)
524  longest = pag->pagf_flcount > 0;
525 
526  if (pag->pagf_freeblks >= needspace + ineed &&
527  longest >= ineed) {
528  xfs_perag_put(pag);
529  return agno;
530  }
531 nextag:
532  xfs_perag_put(pag);
533  /*
534  * No point in iterating over the rest, if we're shutting
535  * down.
536  */
537  if (XFS_FORCED_SHUTDOWN(mp))
538  return NULLAGNUMBER;
539  agno++;
540  if (agno >= agcount)
541  agno = 0;
542  if (agno == pagno) {
543  if (flags == 0)
544  return NULLAGNUMBER;
545  flags = 0;
546  }
547  }
548 }
549 
550 /*
551  * Try to retrieve the next record to the left/right from the current one.
552  */
553 STATIC int
555  struct xfs_btree_cur *cur,
557  int *done,
558  int left)
559 {
560  int error;
561  int i;
562 
563  if (left)
564  error = xfs_btree_decrement(cur, 0, &i);
565  else
566  error = xfs_btree_increment(cur, 0, &i);
567 
568  if (error)
569  return error;
570  *done = !i;
571  if (i) {
572  error = xfs_inobt_get_rec(cur, rec, &i);
573  if (error)
574  return error;
576  }
577 
578  return 0;
579 }
580 
581 STATIC int
583  struct xfs_btree_cur *cur,
584  xfs_agino_t agino,
586  int *done,
587  int left)
588 {
589  int error;
590  int i;
591 
592  error = xfs_inobt_lookup(cur, agino, XFS_LOOKUP_EQ, &i);
593  if (error)
594  return error;
595  *done = !i;
596  if (i) {
597  error = xfs_inobt_get_rec(cur, rec, &i);
598  if (error)
599  return error;
601  }
602 
603  return 0;
604 }
605 
606 /*
607  * Allocate an inode.
608  *
609  * The caller selected an AG for us, and made sure that free inodes are
610  * available.
611  */
612 STATIC int
614  struct xfs_trans *tp,
615  struct xfs_buf *agbp,
616  xfs_ino_t parent,
617  xfs_ino_t *inop)
618 {
619  struct xfs_mount *mp = tp->t_mountp;
620  struct xfs_agi *agi = XFS_BUF_TO_AGI(agbp);
621  xfs_agnumber_t agno = be32_to_cpu(agi->agi_seqno);
622  xfs_agnumber_t pagno = XFS_INO_TO_AGNO(mp, parent);
623  xfs_agino_t pagino = XFS_INO_TO_AGINO(mp, parent);
624  struct xfs_perag *pag;
625  struct xfs_btree_cur *cur, *tcur;
626  struct xfs_inobt_rec_incore rec, trec;
627  xfs_ino_t ino;
628  int error;
629  int offset;
630  int i, j;
631 
632  pag = xfs_perag_get(mp, agno);
633 
634  ASSERT(pag->pagi_init);
635  ASSERT(pag->pagi_inodeok);
636  ASSERT(pag->pagi_freecount > 0);
637 
638  restart_pagno:
639  cur = xfs_inobt_init_cursor(mp, tp, agbp, agno);
640  /*
641  * If pagino is 0 (this is the root inode allocation) use newino.
642  * This must work because we've just allocated some.
643  */
644  if (!pagino)
645  pagino = be32_to_cpu(agi->agi_newino);
646 
647  error = xfs_check_agi_freecount(cur, agi);
648  if (error)
649  goto error0;
650 
651  /*
652  * If in the same AG as the parent, try to get near the parent.
653  */
654  if (pagno == agno) {
655  int doneleft; /* done, to the left */
656  int doneright; /* done, to the right */
657  int searchdistance = 10;
658 
659  error = xfs_inobt_lookup(cur, pagino, XFS_LOOKUP_LE, &i);
660  if (error)
661  goto error0;
662  XFS_WANT_CORRUPTED_GOTO(i == 1, error0);
663 
664  error = xfs_inobt_get_rec(cur, &rec, &j);
665  if (error)
666  goto error0;
667  XFS_WANT_CORRUPTED_GOTO(i == 1, error0);
668 
669  if (rec.ir_freecount > 0) {
670  /*
671  * Found a free inode in the same chunk
672  * as the parent, done.
673  */
674  goto alloc_inode;
675  }
676 
677 
678  /*
679  * In the same AG as parent, but parent's chunk is full.
680  */
681 
682  /* duplicate the cursor, search left & right simultaneously */
683  error = xfs_btree_dup_cursor(cur, &tcur);
684  if (error)
685  goto error0;
686 
687  /*
688  * Skip to last blocks looked up if same parent inode.
689  */
690  if (pagino != NULLAGINO &&
691  pag->pagl_pagino == pagino &&
692  pag->pagl_leftrec != NULLAGINO &&
693  pag->pagl_rightrec != NULLAGINO) {
694  error = xfs_ialloc_get_rec(tcur, pag->pagl_leftrec,
695  &trec, &doneleft, 1);
696  if (error)
697  goto error1;
698 
699  error = xfs_ialloc_get_rec(cur, pag->pagl_rightrec,
700  &rec, &doneright, 0);
701  if (error)
702  goto error1;
703  } else {
704  /* search left with tcur, back up 1 record */
705  error = xfs_ialloc_next_rec(tcur, &trec, &doneleft, 1);
706  if (error)
707  goto error1;
708 
709  /* search right with cur, go forward 1 record. */
710  error = xfs_ialloc_next_rec(cur, &rec, &doneright, 0);
711  if (error)
712  goto error1;
713  }
714 
715  /*
716  * Loop until we find an inode chunk with a free inode.
717  */
718  while (!doneleft || !doneright) {
719  int useleft; /* using left inode chunk this time */
720 
721  if (!--searchdistance) {
722  /*
723  * Not in range - save last search
724  * location and allocate a new inode
725  */
727  pag->pagl_leftrec = trec.ir_startino;
728  pag->pagl_rightrec = rec.ir_startino;
729  pag->pagl_pagino = pagino;
730  goto newino;
731  }
732 
733  /* figure out the closer block if both are valid. */
734  if (!doneleft && !doneright) {
735  useleft = pagino -
736  (trec.ir_startino + XFS_INODES_PER_CHUNK - 1) <
737  rec.ir_startino - pagino;
738  } else {
739  useleft = !doneleft;
740  }
741 
742  /* free inodes to the left? */
743  if (useleft && trec.ir_freecount) {
744  rec = trec;
746  cur = tcur;
747 
748  pag->pagl_leftrec = trec.ir_startino;
749  pag->pagl_rightrec = rec.ir_startino;
750  pag->pagl_pagino = pagino;
751  goto alloc_inode;
752  }
753 
754  /* free inodes to the right? */
755  if (!useleft && rec.ir_freecount) {
757 
758  pag->pagl_leftrec = trec.ir_startino;
759  pag->pagl_rightrec = rec.ir_startino;
760  pag->pagl_pagino = pagino;
761  goto alloc_inode;
762  }
763 
764  /* get next record to check */
765  if (useleft) {
766  error = xfs_ialloc_next_rec(tcur, &trec,
767  &doneleft, 1);
768  } else {
769  error = xfs_ialloc_next_rec(cur, &rec,
770  &doneright, 0);
771  }
772  if (error)
773  goto error1;
774  }
775 
776  /*
777  * We've reached the end of the btree. because
778  * we are only searching a small chunk of the
779  * btree each search, there is obviously free
780  * inodes closer to the parent inode than we
781  * are now. restart the search again.
782  */
783  pag->pagl_pagino = NULLAGINO;
784  pag->pagl_leftrec = NULLAGINO;
785  pag->pagl_rightrec = NULLAGINO;
788  goto restart_pagno;
789  }
790 
791  /*
792  * In a different AG from the parent.
793  * See if the most recently allocated block has any free.
794  */
795 newino:
796  if (agi->agi_newino != cpu_to_be32(NULLAGINO)) {
797  error = xfs_inobt_lookup(cur, be32_to_cpu(agi->agi_newino),
798  XFS_LOOKUP_EQ, &i);
799  if (error)
800  goto error0;
801 
802  if (i == 1) {
803  error = xfs_inobt_get_rec(cur, &rec, &j);
804  if (error)
805  goto error0;
806 
807  if (j == 1 && rec.ir_freecount > 0) {
808  /*
809  * The last chunk allocated in the group
810  * still has a free inode.
811  */
812  goto alloc_inode;
813  }
814  }
815  }
816 
817  /*
818  * None left in the last group, search the whole AG
819  */
820  error = xfs_inobt_lookup(cur, 0, XFS_LOOKUP_GE, &i);
821  if (error)
822  goto error0;
823  XFS_WANT_CORRUPTED_GOTO(i == 1, error0);
824 
825  for (;;) {
826  error = xfs_inobt_get_rec(cur, &rec, &i);
827  if (error)
828  goto error0;
829  XFS_WANT_CORRUPTED_GOTO(i == 1, error0);
830  if (rec.ir_freecount > 0)
831  break;
832  error = xfs_btree_increment(cur, 0, &i);
833  if (error)
834  goto error0;
835  XFS_WANT_CORRUPTED_GOTO(i == 1, error0);
836  }
837 
838 alloc_inode:
839  offset = xfs_lowbit64(rec.ir_free);
840  ASSERT(offset >= 0);
841  ASSERT(offset < XFS_INODES_PER_CHUNK);
843  XFS_INODES_PER_CHUNK) == 0);
844  ino = XFS_AGINO_TO_INO(mp, agno, rec.ir_startino + offset);
845  rec.ir_free &= ~XFS_INOBT_MASK(offset);
846  rec.ir_freecount--;
847  error = xfs_inobt_update(cur, &rec);
848  if (error)
849  goto error0;
850  be32_add_cpu(&agi->agi_freecount, -1);
852  pag->pagi_freecount--;
853 
854  error = xfs_check_agi_freecount(cur, agi);
855  if (error)
856  goto error0;
857 
860  xfs_perag_put(pag);
861  *inop = ino;
862  return 0;
863 error1:
865 error0:
867  xfs_perag_put(pag);
868  return error;
869 }
870 
871 /*
872  * Allocate an inode on disk.
873  *
874  * Mode is used to tell whether the new inode will need space, and whether it
875  * is a directory.
876  *
877  * This function is designed to be called twice if it has to do an allocation
878  * to make more free inodes. On the first call, *IO_agbp should be set to NULL.
879  * If an inode is available without having to performn an allocation, an inode
880  * number is returned. In this case, *IO_agbp would be NULL. If an allocation
881  * needes to be done, xfs_dialloc would return the current AGI buffer in
882  * *IO_agbp. The caller should then commit the current transaction, allocate a
883  * new transaction, and call xfs_dialloc() again, passing in the previous value
884  * of *IO_agbp. IO_agbp should be held across the transactions. Since the AGI
885  * buffer is locked across the two calls, the second call is guaranteed to have
886  * a free inode available.
887  *
888  * Once we successfully pick an inode its number is returned and the on-disk
889  * data structures are updated. The inode itself is not read in, since doing so
890  * would break ordering constraints with xfs_reclaim.
891  */
892 int
894  struct xfs_trans *tp,
895  xfs_ino_t parent,
896  umode_t mode,
897  int okalloc,
898  struct xfs_buf **IO_agbp,
899  xfs_ino_t *inop)
900 {
901  struct xfs_mount *mp = tp->t_mountp;
902  struct xfs_buf *agbp;
903  xfs_agnumber_t agno;
904  int error;
905  int ialloced;
906  int noroom = 0;
907  xfs_agnumber_t start_agno;
908  struct xfs_perag *pag;
909 
910  if (*IO_agbp) {
911  /*
912  * If the caller passes in a pointer to the AGI buffer,
913  * continue where we left off before. In this case, we
914  * know that the allocation group has free inodes.
915  */
916  agbp = *IO_agbp;
917  goto out_alloc;
918  }
919 
920  /*
921  * We do not have an agbp, so select an initial allocation
922  * group for inode allocation.
923  */
924  start_agno = xfs_ialloc_ag_select(tp, parent, mode, okalloc);
925  if (start_agno == NULLAGNUMBER) {
926  *inop = NULLFSINO;
927  return 0;
928  }
929 
930  /*
931  * If we have already hit the ceiling of inode blocks then clear
932  * okalloc so we scan all available agi structures for a free
933  * inode.
934  */
935  if (mp->m_maxicount &&
936  mp->m_sb.sb_icount + XFS_IALLOC_INODES(mp) > mp->m_maxicount) {
937  noroom = 1;
938  okalloc = 0;
939  }
940 
941  /*
942  * Loop until we find an allocation group that either has free inodes
943  * or in which we can allocate some inodes. Iterate through the
944  * allocation groups upward, wrapping at the end.
945  */
946  agno = start_agno;
947  for (;;) {
948  pag = xfs_perag_get(mp, agno);
949  if (!pag->pagi_inodeok) {
950  xfs_ialloc_next_ag(mp);
951  goto nextag;
952  }
953 
954  if (!pag->pagi_init) {
955  error = xfs_ialloc_pagi_init(mp, tp, agno);
956  if (error)
957  goto out_error;
958  }
959 
960  /*
961  * Do a first racy fast path check if this AG is usable.
962  */
963  if (!pag->pagi_freecount && !okalloc)
964  goto nextag;
965 
966  /*
967  * Then read in the AGI buffer and recheck with the AGI buffer
968  * lock held.
969  */
970  error = xfs_ialloc_read_agi(mp, tp, agno, &agbp);
971  if (error)
972  goto out_error;
973 
974  if (pag->pagi_freecount) {
975  xfs_perag_put(pag);
976  goto out_alloc;
977  }
978 
979  if (!okalloc)
980  goto nextag_relse_buffer;
981 
982 
983  error = xfs_ialloc_ag_alloc(tp, agbp, &ialloced);
984  if (error) {
985  xfs_trans_brelse(tp, agbp);
986 
987  if (error != ENOSPC)
988  goto out_error;
989 
990  xfs_perag_put(pag);
991  *inop = NULLFSINO;
992  return 0;
993  }
994 
995  if (ialloced) {
996  /*
997  * We successfully allocated some inodes, return
998  * the current context to the caller so that it
999  * can commit the current transaction and call
1000  * us again where we left off.
1001  */
1002  ASSERT(pag->pagi_freecount > 0);
1003  xfs_perag_put(pag);
1004 
1005  *IO_agbp = agbp;
1006  *inop = NULLFSINO;
1007  return 0;
1008  }
1009 
1010 nextag_relse_buffer:
1011  xfs_trans_brelse(tp, agbp);
1012 nextag:
1013  xfs_perag_put(pag);
1014  if (++agno == mp->m_sb.sb_agcount)
1015  agno = 0;
1016  if (agno == start_agno) {
1017  *inop = NULLFSINO;
1018  return noroom ? ENOSPC : 0;
1019  }
1020  }
1021 
1022 out_alloc:
1023  *IO_agbp = NULL;
1024  return xfs_dialloc_ag(tp, agbp, parent, inop);
1025 out_error:
1026  xfs_perag_put(pag);
1027  return XFS_ERROR(error);
1028 }
1029 
1030 /*
1031  * Free disk inode. Carefully avoids touching the incore inode, all
1032  * manipulations incore are the caller's responsibility.
1033  * The on-disk inode is not changed by this operation, only the
1034  * btree (free inode mask) is changed.
1035  */
1036 int
1038  xfs_trans_t *tp, /* transaction pointer */
1039  xfs_ino_t inode, /* inode to be freed */
1040  xfs_bmap_free_t *flist, /* extents to free */
1041  int *delete, /* set if inode cluster was deleted */
1042  xfs_ino_t *first_ino) /* first inode in deleted cluster */
1043 {
1044  /* REFERENCED */
1045  xfs_agblock_t agbno; /* block number containing inode */
1046  xfs_buf_t *agbp; /* buffer containing allocation group header */
1047  xfs_agino_t agino; /* inode number relative to allocation group */
1048  xfs_agnumber_t agno; /* allocation group number */
1049  xfs_agi_t *agi; /* allocation group header */
1050  xfs_btree_cur_t *cur; /* inode btree cursor */
1051  int error; /* error return value */
1052  int i; /* result code */
1053  int ilen; /* inodes in an inode cluster */
1054  xfs_mount_t *mp; /* mount structure for filesystem */
1055  int off; /* offset of inode in inode chunk */
1056  xfs_inobt_rec_incore_t rec; /* btree record */
1057  struct xfs_perag *pag;
1058 
1059  mp = tp->t_mountp;
1060 
1061  /*
1062  * Break up inode number into its components.
1063  */
1064  agno = XFS_INO_TO_AGNO(mp, inode);
1065  if (agno >= mp->m_sb.sb_agcount) {
1066  xfs_warn(mp, "%s: agno >= mp->m_sb.sb_agcount (%d >= %d).",
1067  __func__, agno, mp->m_sb.sb_agcount);
1068  ASSERT(0);
1069  return XFS_ERROR(EINVAL);
1070  }
1071  agino = XFS_INO_TO_AGINO(mp, inode);
1072  if (inode != XFS_AGINO_TO_INO(mp, agno, agino)) {
1073  xfs_warn(mp, "%s: inode != XFS_AGINO_TO_INO() (%llu != %llu).",
1074  __func__, (unsigned long long)inode,
1075  (unsigned long long)XFS_AGINO_TO_INO(mp, agno, agino));
1076  ASSERT(0);
1077  return XFS_ERROR(EINVAL);
1078  }
1079  agbno = XFS_AGINO_TO_AGBNO(mp, agino);
1080  if (agbno >= mp->m_sb.sb_agblocks) {
1081  xfs_warn(mp, "%s: agbno >= mp->m_sb.sb_agblocks (%d >= %d).",
1082  __func__, agbno, mp->m_sb.sb_agblocks);
1083  ASSERT(0);
1084  return XFS_ERROR(EINVAL);
1085  }
1086  /*
1087  * Get the allocation group header.
1088  */
1089  error = xfs_ialloc_read_agi(mp, tp, agno, &agbp);
1090  if (error) {
1091  xfs_warn(mp, "%s: xfs_ialloc_read_agi() returned error %d.",
1092  __func__, error);
1093  return error;
1094  }
1095  agi = XFS_BUF_TO_AGI(agbp);
1097  ASSERT(agbno < be32_to_cpu(agi->agi_length));
1098  /*
1099  * Initialize the cursor.
1100  */
1101  cur = xfs_inobt_init_cursor(mp, tp, agbp, agno);
1102 
1103  error = xfs_check_agi_freecount(cur, agi);
1104  if (error)
1105  goto error0;
1106 
1107  /*
1108  * Look for the entry describing this inode.
1109  */
1110  if ((error = xfs_inobt_lookup(cur, agino, XFS_LOOKUP_LE, &i))) {
1111  xfs_warn(mp, "%s: xfs_inobt_lookup() returned error %d.",
1112  __func__, error);
1113  goto error0;
1114  }
1115  XFS_WANT_CORRUPTED_GOTO(i == 1, error0);
1116  error = xfs_inobt_get_rec(cur, &rec, &i);
1117  if (error) {
1118  xfs_warn(mp, "%s: xfs_inobt_get_rec() returned error %d.",
1119  __func__, error);
1120  goto error0;
1121  }
1122  XFS_WANT_CORRUPTED_GOTO(i == 1, error0);
1123  /*
1124  * Get the offset in the inode chunk.
1125  */
1126  off = agino - rec.ir_startino;
1127  ASSERT(off >= 0 && off < XFS_INODES_PER_CHUNK);
1128  ASSERT(!(rec.ir_free & XFS_INOBT_MASK(off)));
1129  /*
1130  * Mark the inode free & increment the count.
1131  */
1132  rec.ir_free |= XFS_INOBT_MASK(off);
1133  rec.ir_freecount++;
1134 
1135  /*
1136  * When an inode cluster is free, it becomes eligible for removal
1137  */
1138  if (!(mp->m_flags & XFS_MOUNT_IKEEP) &&
1139  (rec.ir_freecount == XFS_IALLOC_INODES(mp))) {
1140 
1141  *delete = 1;
1142  *first_ino = XFS_AGINO_TO_INO(mp, agno, rec.ir_startino);
1143 
1144  /*
1145  * Remove the inode cluster from the AGI B+Tree, adjust the
1146  * AGI and Superblock inode counts, and mark the disk space
1147  * to be freed when the transaction is committed.
1148  */
1149  ilen = XFS_IALLOC_INODES(mp);
1150  be32_add_cpu(&agi->agi_count, -ilen);
1151  be32_add_cpu(&agi->agi_freecount, -(ilen - 1));
1153  pag = xfs_perag_get(mp, agno);
1154  pag->pagi_freecount -= ilen - 1;
1155  xfs_perag_put(pag);
1157  xfs_trans_mod_sb(tp, XFS_TRANS_SB_IFREE, -(ilen - 1));
1158 
1159  if ((error = xfs_btree_delete(cur, &i))) {
1160  xfs_warn(mp, "%s: xfs_btree_delete returned error %d.",
1161  __func__, error);
1162  goto error0;
1163  }
1164 
1166  agno, XFS_INO_TO_AGBNO(mp,rec.ir_startino)),
1167  XFS_IALLOC_BLOCKS(mp), flist, mp);
1168  } else {
1169  *delete = 0;
1170 
1171  error = xfs_inobt_update(cur, &rec);
1172  if (error) {
1173  xfs_warn(mp, "%s: xfs_inobt_update returned error %d.",
1174  __func__, error);
1175  goto error0;
1176  }
1177 
1178  /*
1179  * Change the inode free counts and log the ag/sb changes.
1180  */
1181  be32_add_cpu(&agi->agi_freecount, 1);
1183  pag = xfs_perag_get(mp, agno);
1184  pag->pagi_freecount++;
1185  xfs_perag_put(pag);
1187  }
1188 
1189  error = xfs_check_agi_freecount(cur, agi);
1190  if (error)
1191  goto error0;
1192 
1194  return 0;
1195 
1196 error0:
1198  return error;
1199 }
1200 
1201 STATIC int
1203  struct xfs_mount *mp,
1204  struct xfs_trans *tp,
1205  xfs_agnumber_t agno,
1206  xfs_agino_t agino,
1207  xfs_agblock_t agbno,
1208  xfs_agblock_t *chunk_agbno,
1209  xfs_agblock_t *offset_agbno,
1210  int flags)
1211 {
1212  struct xfs_inobt_rec_incore rec;
1213  struct xfs_btree_cur *cur;
1214  struct xfs_buf *agbp;
1215  int error;
1216  int i;
1217 
1218  error = xfs_ialloc_read_agi(mp, tp, agno, &agbp);
1219  if (error) {
1220  xfs_alert(mp,
1221  "%s: xfs_ialloc_read_agi() returned error %d, agno %d",
1222  __func__, error, agno);
1223  return error;
1224  }
1225 
1226  /*
1227  * Lookup the inode record for the given agino. If the record cannot be
1228  * found, then it's an invalid inode number and we should abort. Once
1229  * we have a record, we need to ensure it contains the inode number
1230  * we are looking up.
1231  */
1232  cur = xfs_inobt_init_cursor(mp, tp, agbp, agno);
1233  error = xfs_inobt_lookup(cur, agino, XFS_LOOKUP_LE, &i);
1234  if (!error) {
1235  if (i)
1236  error = xfs_inobt_get_rec(cur, &rec, &i);
1237  if (!error && i == 0)
1238  error = EINVAL;
1239  }
1240 
1241  xfs_trans_brelse(tp, agbp);
1243  if (error)
1244  return error;
1245 
1246  /* check that the returned record contains the required inode */
1247  if (rec.ir_startino > agino ||
1248  rec.ir_startino + XFS_IALLOC_INODES(mp) <= agino)
1249  return EINVAL;
1250 
1251  /* for untrusted inodes check it is allocated first */
1252  if ((flags & XFS_IGET_UNTRUSTED) &&
1253  (rec.ir_free & XFS_INOBT_MASK(agino - rec.ir_startino)))
1254  return EINVAL;
1255 
1256  *chunk_agbno = XFS_AGINO_TO_AGBNO(mp, rec.ir_startino);
1257  *offset_agbno = agbno - *chunk_agbno;
1258  return 0;
1259 }
1260 
1261 /*
1262  * Return the location of the inode in imap, for mapping it into a buffer.
1263  */
1264 int
1266  xfs_mount_t *mp, /* file system mount structure */
1267  xfs_trans_t *tp, /* transaction pointer */
1268  xfs_ino_t ino, /* inode to locate */
1269  struct xfs_imap *imap, /* location map structure */
1270  uint flags) /* flags for inode btree lookup */
1271 {
1272  xfs_agblock_t agbno; /* block number of inode in the alloc group */
1273  xfs_agino_t agino; /* inode number within alloc group */
1274  xfs_agnumber_t agno; /* allocation group number */
1275  int blks_per_cluster; /* num blocks per inode cluster */
1276  xfs_agblock_t chunk_agbno; /* first block in inode chunk */
1277  xfs_agblock_t cluster_agbno; /* first block in inode cluster */
1278  int error; /* error code */
1279  int offset; /* index of inode in its buffer */
1280  int offset_agbno; /* blks from chunk start to inode */
1281 
1282  ASSERT(ino != NULLFSINO);
1283 
1284  /*
1285  * Split up the inode number into its parts.
1286  */
1287  agno = XFS_INO_TO_AGNO(mp, ino);
1288  agino = XFS_INO_TO_AGINO(mp, ino);
1289  agbno = XFS_AGINO_TO_AGBNO(mp, agino);
1290  if (agno >= mp->m_sb.sb_agcount || agbno >= mp->m_sb.sb_agblocks ||
1291  ino != XFS_AGINO_TO_INO(mp, agno, agino)) {
1292 #ifdef DEBUG
1293  /*
1294  * Don't output diagnostic information for untrusted inodes
1295  * as they can be invalid without implying corruption.
1296  */
1297  if (flags & XFS_IGET_UNTRUSTED)
1298  return XFS_ERROR(EINVAL);
1299  if (agno >= mp->m_sb.sb_agcount) {
1300  xfs_alert(mp,
1301  "%s: agno (%d) >= mp->m_sb.sb_agcount (%d)",
1302  __func__, agno, mp->m_sb.sb_agcount);
1303  }
1304  if (agbno >= mp->m_sb.sb_agblocks) {
1305  xfs_alert(mp,
1306  "%s: agbno (0x%llx) >= mp->m_sb.sb_agblocks (0x%lx)",
1307  __func__, (unsigned long long)agbno,
1308  (unsigned long)mp->m_sb.sb_agblocks);
1309  }
1310  if (ino != XFS_AGINO_TO_INO(mp, agno, agino)) {
1311  xfs_alert(mp,
1312  "%s: ino (0x%llx) != XFS_AGINO_TO_INO() (0x%llx)",
1313  __func__, ino,
1314  XFS_AGINO_TO_INO(mp, agno, agino));
1315  }
1316  xfs_stack_trace();
1317 #endif /* DEBUG */
1318  return XFS_ERROR(EINVAL);
1319  }
1320 
1321  blks_per_cluster = XFS_INODE_CLUSTER_SIZE(mp) >> mp->m_sb.sb_blocklog;
1322 
1323  /*
1324  * For bulkstat and handle lookups, we have an untrusted inode number
1325  * that we have to verify is valid. We cannot do this just by reading
1326  * the inode buffer as it may have been unlinked and removed leaving
1327  * inodes in stale state on disk. Hence we have to do a btree lookup
1328  * in all cases where an untrusted inode number is passed.
1329  */
1330  if (flags & XFS_IGET_UNTRUSTED) {
1331  error = xfs_imap_lookup(mp, tp, agno, agino, agbno,
1332  &chunk_agbno, &offset_agbno, flags);
1333  if (error)
1334  return error;
1335  goto out_map;
1336  }
1337 
1338  /*
1339  * If the inode cluster size is the same as the blocksize or
1340  * smaller we get to the buffer by simple arithmetics.
1341  */
1342  if (XFS_INODE_CLUSTER_SIZE(mp) <= mp->m_sb.sb_blocksize) {
1343  offset = XFS_INO_TO_OFFSET(mp, ino);
1344  ASSERT(offset < mp->m_sb.sb_inopblock);
1345 
1346  imap->im_blkno = XFS_AGB_TO_DADDR(mp, agno, agbno);
1347  imap->im_len = XFS_FSB_TO_BB(mp, 1);
1348  imap->im_boffset = (ushort)(offset << mp->m_sb.sb_inodelog);
1349  return 0;
1350  }
1351 
1352  /*
1353  * If the inode chunks are aligned then use simple maths to
1354  * find the location. Otherwise we have to do a btree
1355  * lookup to find the location.
1356  */
1357  if (mp->m_inoalign_mask) {
1358  offset_agbno = agbno & mp->m_inoalign_mask;
1359  chunk_agbno = agbno - offset_agbno;
1360  } else {
1361  error = xfs_imap_lookup(mp, tp, agno, agino, agbno,
1362  &chunk_agbno, &offset_agbno, flags);
1363  if (error)
1364  return error;
1365  }
1366 
1367 out_map:
1368  ASSERT(agbno >= chunk_agbno);
1369  cluster_agbno = chunk_agbno +
1370  ((offset_agbno / blks_per_cluster) * blks_per_cluster);
1371  offset = ((agbno - cluster_agbno) * mp->m_sb.sb_inopblock) +
1372  XFS_INO_TO_OFFSET(mp, ino);
1373 
1374  imap->im_blkno = XFS_AGB_TO_DADDR(mp, agno, cluster_agbno);
1375  imap->im_len = XFS_FSB_TO_BB(mp, blks_per_cluster);
1376  imap->im_boffset = (ushort)(offset << mp->m_sb.sb_inodelog);
1377 
1378  /*
1379  * If the inode number maps to a block outside the bounds
1380  * of the file system then return NULL rather than calling
1381  * read_buf and panicing when we get an error from the
1382  * driver.
1383  */
1384  if ((imap->im_blkno + imap->im_len) >
1385  XFS_FSB_TO_BB(mp, mp->m_sb.sb_dblocks)) {
1386  xfs_alert(mp,
1387  "%s: (im_blkno (0x%llx) + im_len (0x%llx)) > sb_dblocks (0x%llx)",
1388  __func__, (unsigned long long) imap->im_blkno,
1389  (unsigned long long) imap->im_len,
1390  XFS_FSB_TO_BB(mp, mp->m_sb.sb_dblocks));
1391  return XFS_ERROR(EINVAL);
1392  }
1393  return 0;
1394 }
1395 
1396 /*
1397  * Compute and fill in value of m_in_maxlevels.
1398  */
1399 void
1401  xfs_mount_t *mp) /* file system mount structure */
1402 {
1403  int level;
1404  uint maxblocks;
1405  uint maxleafents;
1406  int minleafrecs;
1407  int minnoderecs;
1408 
1409  maxleafents = (1LL << XFS_INO_AGINO_BITS(mp)) >>
1411  minleafrecs = mp->m_alloc_mnr[0];
1412  minnoderecs = mp->m_alloc_mnr[1];
1413  maxblocks = (maxleafents + minleafrecs - 1) / minleafrecs;
1414  for (level = 1; maxblocks > 1; level++)
1415  maxblocks = (maxblocks + minnoderecs - 1) / minnoderecs;
1416  mp->m_in_maxlevels = level;
1417 }
1418 
1419 /*
1420  * Log specified fields for the ag hdr (inode section)
1421  */
1422 void
1424  xfs_trans_t *tp, /* transaction pointer */
1425  xfs_buf_t *bp, /* allocation group header buffer */
1426  int fields) /* bitmask of fields to log */
1427 {
1428  int first; /* first byte number */
1429  int last; /* last byte number */
1430  static const short offsets[] = { /* field starting offsets */
1431  /* keep in sync with bit definitions */
1432  offsetof(xfs_agi_t, agi_magicnum),
1433  offsetof(xfs_agi_t, agi_versionnum),
1434  offsetof(xfs_agi_t, agi_seqno),
1435  offsetof(xfs_agi_t, agi_length),
1436  offsetof(xfs_agi_t, agi_count),
1437  offsetof(xfs_agi_t, agi_root),
1438  offsetof(xfs_agi_t, agi_level),
1439  offsetof(xfs_agi_t, agi_freecount),
1440  offsetof(xfs_agi_t, agi_newino),
1441  offsetof(xfs_agi_t, agi_dirino),
1442  offsetof(xfs_agi_t, agi_unlinked),
1443  sizeof(xfs_agi_t)
1444  };
1445 #ifdef DEBUG
1446  xfs_agi_t *agi; /* allocation group header */
1447 
1448  agi = XFS_BUF_TO_AGI(bp);
1450 #endif
1451  /*
1452  * Compute byte offsets for the first and last fields.
1453  */
1454  xfs_btree_offsets(fields, offsets, XFS_AGI_NUM_BITS, &first, &last);
1455  /*
1456  * Log the allocation group inode header buffer.
1457  */
1458  xfs_trans_log_buf(tp, bp, first, last);
1459 }
1460 
1461 #ifdef DEBUG
1462 STATIC void
1464  struct xfs_agi *agi)
1465 {
1466  int i;
1467 
1468  for (i = 0; i < XFS_AGI_UNLINKED_BUCKETS; i++)
1469  ASSERT(agi->agi_unlinked[i]);
1470 }
1471 #else
1472 #define xfs_check_agi_unlinked(agi)
1473 #endif
1474 
1475 /*
1476  * Read in the allocation group header (inode allocation section)
1477  */
1478 int
1480  struct xfs_mount *mp, /* file system mount structure */
1481  struct xfs_trans *tp, /* transaction pointer */
1482  xfs_agnumber_t agno, /* allocation group number */
1483  struct xfs_buf **bpp) /* allocation group hdr buf */
1484 {
1485  struct xfs_agi *agi; /* allocation group header */
1486  int agi_ok; /* agi is consistent */
1487  int error;
1488 
1489  ASSERT(agno != NULLAGNUMBER);
1490 
1491  error = xfs_trans_read_buf(mp, tp, mp->m_ddev_targp,
1492  XFS_AG_DADDR(mp, agno, XFS_AGI_DADDR(mp)),
1493  XFS_FSS_TO_BB(mp, 1), 0, bpp);
1494  if (error)
1495  return error;
1496 
1497  ASSERT(!xfs_buf_geterror(*bpp));
1498  agi = XFS_BUF_TO_AGI(*bpp);
1499 
1500  /*
1501  * Validate the magic number of the agi block.
1502  */
1503  agi_ok = agi->agi_magicnum == cpu_to_be32(XFS_AGI_MAGIC) &&
1505  be32_to_cpu(agi->agi_seqno) == agno;
1508  XFS_CORRUPTION_ERROR("xfs_read_agi", XFS_ERRLEVEL_LOW,
1509  mp, agi);
1510  xfs_trans_brelse(tp, *bpp);
1511  return XFS_ERROR(EFSCORRUPTED);
1512  }
1513 
1514  xfs_buf_set_ref(*bpp, XFS_AGI_REF);
1515 
1517  return 0;
1518 }
1519 
1520 int
1522  struct xfs_mount *mp, /* file system mount structure */
1523  struct xfs_trans *tp, /* transaction pointer */
1524  xfs_agnumber_t agno, /* allocation group number */
1525  struct xfs_buf **bpp) /* allocation group hdr buf */
1526 {
1527  struct xfs_agi *agi; /* allocation group header */
1528  struct xfs_perag *pag; /* per allocation group data */
1529  int error;
1530 
1531  error = xfs_read_agi(mp, tp, agno, bpp);
1532  if (error)
1533  return error;
1534 
1535  agi = XFS_BUF_TO_AGI(*bpp);
1536  pag = xfs_perag_get(mp, agno);
1537  if (!pag->pagi_init) {
1539  pag->pagi_count = be32_to_cpu(agi->agi_count);
1540  pag->pagi_init = 1;
1541  }
1542 
1543  /*
1544  * It's possible for these to be out of sync if
1545  * we are in the middle of a forced shutdown.
1546  */
1548  XFS_FORCED_SHUTDOWN(mp));
1549  xfs_perag_put(pag);
1550  return 0;
1551 }
1552 
1553 /*
1554  * Read in the agi to initialise the per-ag data in the mount structure
1555  */
1556 int
1558  xfs_mount_t *mp, /* file system mount structure */
1559  xfs_trans_t *tp, /* transaction pointer */
1560  xfs_agnumber_t agno) /* allocation group number */
1561 {
1562  xfs_buf_t *bp = NULL;
1563  int error;
1564 
1565  error = xfs_ialloc_read_agi(mp, tp, agno, &bp);
1566  if (error)
1567  return error;
1568  if (bp)
1569  xfs_trans_brelse(tp, bp);
1570  return 0;
1571 }