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TOMOYO Linux Cross Reference
Linux/fs/xfs/xfs_log_recover.c

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  1 /*
  2  * Copyright (c) 2000-2006 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_error.h"
 29 #include "xfs_bmap_btree.h"
 30 #include "xfs_alloc_btree.h"
 31 #include "xfs_ialloc_btree.h"
 32 #include "xfs_dinode.h"
 33 #include "xfs_inode.h"
 34 #include "xfs_inode_item.h"
 35 #include "xfs_alloc.h"
 36 #include "xfs_ialloc.h"
 37 #include "xfs_log_priv.h"
 38 #include "xfs_buf_item.h"
 39 #include "xfs_log_recover.h"
 40 #include "xfs_extfree_item.h"
 41 #include "xfs_trans_priv.h"
 42 #include "xfs_quota.h"
 43 #include "xfs_rw.h"
 44 #include "xfs_utils.h"
 45 #include "xfs_trace.h"
 46 
 47 STATIC int      xlog_find_zeroed(xlog_t *, xfs_daddr_t *);
 48 STATIC int      xlog_clear_stale_blocks(xlog_t *, xfs_lsn_t);
 49 #if defined(DEBUG)
 50 STATIC void     xlog_recover_check_summary(xlog_t *);
 51 #else
 52 #define xlog_recover_check_summary(log)
 53 #endif
 54 
 55 /*
 56  * This structure is used during recovery to record the buf log items which
 57  * have been canceled and should not be replayed.
 58  */
 59 struct xfs_buf_cancel {
 60         xfs_daddr_t             bc_blkno;
 61         uint                    bc_len;
 62         int                     bc_refcount;
 63         struct list_head        bc_list;
 64 };
 65 
 66 /*
 67  * Sector aligned buffer routines for buffer create/read/write/access
 68  */
 69 
 70 /*
 71  * Verify the given count of basic blocks is valid number of blocks
 72  * to specify for an operation involving the given XFS log buffer.
 73  * Returns nonzero if the count is valid, 0 otherwise.
 74  */
 75 
 76 static inline int
 77 xlog_buf_bbcount_valid(
 78         xlog_t          *log,
 79         int             bbcount)
 80 {
 81         return bbcount > 0 && bbcount <= log->l_logBBsize;
 82 }
 83 
 84 /*
 85  * Allocate a buffer to hold log data.  The buffer needs to be able
 86  * to map to a range of nbblks basic blocks at any valid (basic
 87  * block) offset within the log.
 88  */
 89 STATIC xfs_buf_t *
 90 xlog_get_bp(
 91         xlog_t          *log,
 92         int             nbblks)
 93 {
 94         struct xfs_buf  *bp;
 95 
 96         if (!xlog_buf_bbcount_valid(log, nbblks)) {
 97                 xfs_warn(log->l_mp, "Invalid block length (0x%x) for buffer",
 98                         nbblks);
 99                 XFS_ERROR_REPORT(__func__, XFS_ERRLEVEL_HIGH, log->l_mp);
100                 return NULL;
101         }
102 
103         /*
104          * We do log I/O in units of log sectors (a power-of-2
105          * multiple of the basic block size), so we round up the
106          * requested size to accommodate the basic blocks required
107          * for complete log sectors.
108          *
109          * In addition, the buffer may be used for a non-sector-
110          * aligned block offset, in which case an I/O of the
111          * requested size could extend beyond the end of the
112          * buffer.  If the requested size is only 1 basic block it
113          * will never straddle a sector boundary, so this won't be
114          * an issue.  Nor will this be a problem if the log I/O is
115          * done in basic blocks (sector size 1).  But otherwise we
116          * extend the buffer by one extra log sector to ensure
117          * there's space to accommodate this possibility.
118          */
119         if (nbblks > 1 && log->l_sectBBsize > 1)
120                 nbblks += log->l_sectBBsize;
121         nbblks = round_up(nbblks, log->l_sectBBsize);
122 
123         bp = xfs_buf_get_uncached(log->l_mp->m_logdev_targp, BBTOB(nbblks), 0);
124         if (bp)
125                 xfs_buf_unlock(bp);
126         return bp;
127 }
128 
129 STATIC void
130 xlog_put_bp(
131         xfs_buf_t       *bp)
132 {
133         xfs_buf_free(bp);
134 }
135 
136 /*
137  * Return the address of the start of the given block number's data
138  * in a log buffer.  The buffer covers a log sector-aligned region.
139  */
140 STATIC xfs_caddr_t
141 xlog_align(
142         xlog_t          *log,
143         xfs_daddr_t     blk_no,
144         int             nbblks,
145         xfs_buf_t       *bp)
146 {
147         xfs_daddr_t     offset = blk_no & ((xfs_daddr_t)log->l_sectBBsize - 1);
148 
149         ASSERT(BBTOB(offset + nbblks) <= XFS_BUF_SIZE(bp));
150         return bp->b_addr + BBTOB(offset);
151 }
152 
153 
154 /*
155  * nbblks should be uint, but oh well.  Just want to catch that 32-bit length.
156  */
157 STATIC int
158 xlog_bread_noalign(
159         xlog_t          *log,
160         xfs_daddr_t     blk_no,
161         int             nbblks,
162         xfs_buf_t       *bp)
163 {
164         int             error;
165 
166         if (!xlog_buf_bbcount_valid(log, nbblks)) {
167                 xfs_warn(log->l_mp, "Invalid block length (0x%x) for buffer",
168                         nbblks);
169                 XFS_ERROR_REPORT(__func__, XFS_ERRLEVEL_HIGH, log->l_mp);
170                 return EFSCORRUPTED;
171         }
172 
173         blk_no = round_down(blk_no, log->l_sectBBsize);
174         nbblks = round_up(nbblks, log->l_sectBBsize);
175 
176         ASSERT(nbblks > 0);
177         ASSERT(BBTOB(nbblks) <= XFS_BUF_SIZE(bp));
178 
179         XFS_BUF_SET_ADDR(bp, log->l_logBBstart + blk_no);
180         XFS_BUF_READ(bp);
181         XFS_BUF_SET_COUNT(bp, BBTOB(nbblks));
182 
183         xfsbdstrat(log->l_mp, bp);
184         error = xfs_buf_iowait(bp);
185         if (error)
186                 xfs_ioerror_alert("xlog_bread", log->l_mp,
187                                   bp, XFS_BUF_ADDR(bp));
188         return error;
189 }
190 
191 STATIC int
192 xlog_bread(
193         xlog_t          *log,
194         xfs_daddr_t     blk_no,
195         int             nbblks,
196         xfs_buf_t       *bp,
197         xfs_caddr_t     *offset)
198 {
199         int             error;
200 
201         error = xlog_bread_noalign(log, blk_no, nbblks, bp);
202         if (error)
203                 return error;
204 
205         *offset = xlog_align(log, blk_no, nbblks, bp);
206         return 0;
207 }
208 
209 /*
210  * Read at an offset into the buffer. Returns with the buffer in it's original
211  * state regardless of the result of the read.
212  */
213 STATIC int
214 xlog_bread_offset(
215         xlog_t          *log,
216         xfs_daddr_t     blk_no,         /* block to read from */
217         int             nbblks,         /* blocks to read */
218         xfs_buf_t       *bp,
219         xfs_caddr_t     offset)
220 {
221         xfs_caddr_t     orig_offset = bp->b_addr;
222         int             orig_len = bp->b_buffer_length;
223         int             error, error2;
224 
225         error = xfs_buf_associate_memory(bp, offset, BBTOB(nbblks));
226         if (error)
227                 return error;
228 
229         error = xlog_bread_noalign(log, blk_no, nbblks, bp);
230 
231         /* must reset buffer pointer even on error */
232         error2 = xfs_buf_associate_memory(bp, orig_offset, orig_len);
233         if (error)
234                 return error;
235         return error2;
236 }
237 
238 /*
239  * Write out the buffer at the given block for the given number of blocks.
240  * The buffer is kept locked across the write and is returned locked.
241  * This can only be used for synchronous log writes.
242  */
243 STATIC int
244 xlog_bwrite(
245         xlog_t          *log,
246         xfs_daddr_t     blk_no,
247         int             nbblks,
248         xfs_buf_t       *bp)
249 {
250         int             error;
251 
252         if (!xlog_buf_bbcount_valid(log, nbblks)) {
253                 xfs_warn(log->l_mp, "Invalid block length (0x%x) for buffer",
254                         nbblks);
255                 XFS_ERROR_REPORT(__func__, XFS_ERRLEVEL_HIGH, log->l_mp);
256                 return EFSCORRUPTED;
257         }
258 
259         blk_no = round_down(blk_no, log->l_sectBBsize);
260         nbblks = round_up(nbblks, log->l_sectBBsize);
261 
262         ASSERT(nbblks > 0);
263         ASSERT(BBTOB(nbblks) <= XFS_BUF_SIZE(bp));
264 
265         XFS_BUF_SET_ADDR(bp, log->l_logBBstart + blk_no);
266         XFS_BUF_ZEROFLAGS(bp);
267         xfs_buf_hold(bp);
268         xfs_buf_lock(bp);
269         XFS_BUF_SET_COUNT(bp, BBTOB(nbblks));
270 
271         if ((error = xfs_bwrite(log->l_mp, bp)))
272                 xfs_ioerror_alert("xlog_bwrite", log->l_mp,
273                                   bp, XFS_BUF_ADDR(bp));
274         return error;
275 }
276 
277 #ifdef DEBUG
278 /*
279  * dump debug superblock and log record information
280  */
281 STATIC void
282 xlog_header_check_dump(
283         xfs_mount_t             *mp,
284         xlog_rec_header_t       *head)
285 {
286         xfs_debug(mp, "%s:  SB : uuid = %pU, fmt = %d\n",
287                 __func__, &mp->m_sb.sb_uuid, XLOG_FMT);
288         xfs_debug(mp, "    log : uuid = %pU, fmt = %d\n",
289                 &head->h_fs_uuid, be32_to_cpu(head->h_fmt));
290 }
291 #else
292 #define xlog_header_check_dump(mp, head)
293 #endif
294 
295 /*
296  * check log record header for recovery
297  */
298 STATIC int
299 xlog_header_check_recover(
300         xfs_mount_t             *mp,
301         xlog_rec_header_t       *head)
302 {
303         ASSERT(head->h_magicno == cpu_to_be32(XLOG_HEADER_MAGIC_NUM));
304 
305         /*
306          * IRIX doesn't write the h_fmt field and leaves it zeroed
307          * (XLOG_FMT_UNKNOWN). This stops us from trying to recover
308          * a dirty log created in IRIX.
309          */
310         if (unlikely(head->h_fmt != cpu_to_be32(XLOG_FMT))) {
311                 xfs_warn(mp,
312         "dirty log written in incompatible format - can't recover");
313                 xlog_header_check_dump(mp, head);
314                 XFS_ERROR_REPORT("xlog_header_check_recover(1)",
315                                  XFS_ERRLEVEL_HIGH, mp);
316                 return XFS_ERROR(EFSCORRUPTED);
317         } else if (unlikely(!uuid_equal(&mp->m_sb.sb_uuid, &head->h_fs_uuid))) {
318                 xfs_warn(mp,
319         "dirty log entry has mismatched uuid - can't recover");
320                 xlog_header_check_dump(mp, head);
321                 XFS_ERROR_REPORT("xlog_header_check_recover(2)",
322                                  XFS_ERRLEVEL_HIGH, mp);
323                 return XFS_ERROR(EFSCORRUPTED);
324         }
325         return 0;
326 }
327 
328 /*
329  * read the head block of the log and check the header
330  */
331 STATIC int
332 xlog_header_check_mount(
333         xfs_mount_t             *mp,
334         xlog_rec_header_t       *head)
335 {
336         ASSERT(head->h_magicno == cpu_to_be32(XLOG_HEADER_MAGIC_NUM));
337 
338         if (uuid_is_nil(&head->h_fs_uuid)) {
339                 /*
340                  * IRIX doesn't write the h_fs_uuid or h_fmt fields. If
341                  * h_fs_uuid is nil, we assume this log was last mounted
342                  * by IRIX and continue.
343                  */
344                 xfs_warn(mp, "nil uuid in log - IRIX style log");
345         } else if (unlikely(!uuid_equal(&mp->m_sb.sb_uuid, &head->h_fs_uuid))) {
346                 xfs_warn(mp, "log has mismatched uuid - can't recover");
347                 xlog_header_check_dump(mp, head);
348                 XFS_ERROR_REPORT("xlog_header_check_mount",
349                                  XFS_ERRLEVEL_HIGH, mp);
350                 return XFS_ERROR(EFSCORRUPTED);
351         }
352         return 0;
353 }
354 
355 STATIC void
356 xlog_recover_iodone(
357         struct xfs_buf  *bp)
358 {
359         if (bp->b_error) {
360                 /*
361                  * We're not going to bother about retrying
362                  * this during recovery. One strike!
363                  */
364                 xfs_ioerror_alert("xlog_recover_iodone",
365                                         bp->b_target->bt_mount, bp,
366                                         XFS_BUF_ADDR(bp));
367                 xfs_force_shutdown(bp->b_target->bt_mount,
368                                         SHUTDOWN_META_IO_ERROR);
369         }
370         bp->b_iodone = NULL;
371         xfs_buf_ioend(bp, 0);
372 }
373 
374 /*
375  * This routine finds (to an approximation) the first block in the physical
376  * log which contains the given cycle.  It uses a binary search algorithm.
377  * Note that the algorithm can not be perfect because the disk will not
378  * necessarily be perfect.
379  */
380 STATIC int
381 xlog_find_cycle_start(
382         xlog_t          *log,
383         xfs_buf_t       *bp,
384         xfs_daddr_t     first_blk,
385         xfs_daddr_t     *last_blk,
386         uint            cycle)
387 {
388         xfs_caddr_t     offset;
389         xfs_daddr_t     mid_blk;
390         xfs_daddr_t     end_blk;
391         uint            mid_cycle;
392         int             error;
393 
394         end_blk = *last_blk;
395         mid_blk = BLK_AVG(first_blk, end_blk);
396         while (mid_blk != first_blk && mid_blk != end_blk) {
397                 error = xlog_bread(log, mid_blk, 1, bp, &offset);
398                 if (error)
399                         return error;
400                 mid_cycle = xlog_get_cycle(offset);
401                 if (mid_cycle == cycle)
402                         end_blk = mid_blk;   /* last_half_cycle == mid_cycle */
403                 else
404                         first_blk = mid_blk; /* first_half_cycle == mid_cycle */
405                 mid_blk = BLK_AVG(first_blk, end_blk);
406         }
407         ASSERT((mid_blk == first_blk && mid_blk+1 == end_blk) ||
408                (mid_blk == end_blk && mid_blk-1 == first_blk));
409 
410         *last_blk = end_blk;
411 
412         return 0;
413 }
414 
415 /*
416  * Check that a range of blocks does not contain stop_on_cycle_no.
417  * Fill in *new_blk with the block offset where such a block is
418  * found, or with -1 (an invalid block number) if there is no such
419  * block in the range.  The scan needs to occur from front to back
420  * and the pointer into the region must be updated since a later
421  * routine will need to perform another test.
422  */
423 STATIC int
424 xlog_find_verify_cycle(
425         xlog_t          *log,
426         xfs_daddr_t     start_blk,
427         int             nbblks,
428         uint            stop_on_cycle_no,
429         xfs_daddr_t     *new_blk)
430 {
431         xfs_daddr_t     i, j;
432         uint            cycle;
433         xfs_buf_t       *bp;
434         xfs_daddr_t     bufblks;
435         xfs_caddr_t     buf = NULL;
436         int             error = 0;
437 
438         /*
439          * Greedily allocate a buffer big enough to handle the full
440          * range of basic blocks we'll be examining.  If that fails,
441          * try a smaller size.  We need to be able to read at least
442          * a log sector, or we're out of luck.
443          */
444         bufblks = 1 << ffs(nbblks);
445         while (!(bp = xlog_get_bp(log, bufblks))) {
446                 bufblks >>= 1;
447                 if (bufblks < log->l_sectBBsize)
448                         return ENOMEM;
449         }
450 
451         for (i = start_blk; i < start_blk + nbblks; i += bufblks) {
452                 int     bcount;
453 
454                 bcount = min(bufblks, (start_blk + nbblks - i));
455 
456                 error = xlog_bread(log, i, bcount, bp, &buf);
457                 if (error)
458                         goto out;
459 
460                 for (j = 0; j < bcount; j++) {
461                         cycle = xlog_get_cycle(buf);
462                         if (cycle == stop_on_cycle_no) {
463                                 *new_blk = i+j;
464                                 goto out;
465                         }
466 
467                         buf += BBSIZE;
468                 }
469         }
470 
471         *new_blk = -1;
472 
473 out:
474         xlog_put_bp(bp);
475         return error;
476 }
477 
478 /*
479  * Potentially backup over partial log record write.
480  *
481  * In the typical case, last_blk is the number of the block directly after
482  * a good log record.  Therefore, we subtract one to get the block number
483  * of the last block in the given buffer.  extra_bblks contains the number
484  * of blocks we would have read on a previous read.  This happens when the
485  * last log record is split over the end of the physical log.
486  *
487  * extra_bblks is the number of blocks potentially verified on a previous
488  * call to this routine.
489  */
490 STATIC int
491 xlog_find_verify_log_record(
492         xlog_t                  *log,
493         xfs_daddr_t             start_blk,
494         xfs_daddr_t             *last_blk,
495         int                     extra_bblks)
496 {
497         xfs_daddr_t             i;
498         xfs_buf_t               *bp;
499         xfs_caddr_t             offset = NULL;
500         xlog_rec_header_t       *head = NULL;
501         int                     error = 0;
502         int                     smallmem = 0;
503         int                     num_blks = *last_blk - start_blk;
504         int                     xhdrs;
505 
506         ASSERT(start_blk != 0 || *last_blk != start_blk);
507 
508         if (!(bp = xlog_get_bp(log, num_blks))) {
509                 if (!(bp = xlog_get_bp(log, 1)))
510                         return ENOMEM;
511                 smallmem = 1;
512         } else {
513                 error = xlog_bread(log, start_blk, num_blks, bp, &offset);
514                 if (error)
515                         goto out;
516                 offset += ((num_blks - 1) << BBSHIFT);
517         }
518 
519         for (i = (*last_blk) - 1; i >= 0; i--) {
520                 if (i < start_blk) {
521                         /* valid log record not found */
522                         xfs_warn(log->l_mp,
523                 "Log inconsistent (didn't find previous header)");
524                         ASSERT(0);
525                         error = XFS_ERROR(EIO);
526                         goto out;
527                 }
528 
529                 if (smallmem) {
530                         error = xlog_bread(log, i, 1, bp, &offset);
531                         if (error)
532                                 goto out;
533                 }
534 
535                 head = (xlog_rec_header_t *)offset;
536 
537                 if (head->h_magicno == cpu_to_be32(XLOG_HEADER_MAGIC_NUM))
538                         break;
539 
540                 if (!smallmem)
541                         offset -= BBSIZE;
542         }
543 
544         /*
545          * We hit the beginning of the physical log & still no header.  Return
546          * to caller.  If caller can handle a return of -1, then this routine
547          * will be called again for the end of the physical log.
548          */
549         if (i == -1) {
550                 error = -1;
551                 goto out;
552         }
553 
554         /*
555          * We have the final block of the good log (the first block
556          * of the log record _before_ the head. So we check the uuid.
557          */
558         if ((error = xlog_header_check_mount(log->l_mp, head)))
559                 goto out;
560 
561         /*
562          * We may have found a log record header before we expected one.
563          * last_blk will be the 1st block # with a given cycle #.  We may end
564          * up reading an entire log record.  In this case, we don't want to
565          * reset last_blk.  Only when last_blk points in the middle of a log
566          * record do we update last_blk.
567          */
568         if (xfs_sb_version_haslogv2(&log->l_mp->m_sb)) {
569                 uint    h_size = be32_to_cpu(head->h_size);
570 
571                 xhdrs = h_size / XLOG_HEADER_CYCLE_SIZE;
572                 if (h_size % XLOG_HEADER_CYCLE_SIZE)
573                         xhdrs++;
574         } else {
575                 xhdrs = 1;
576         }
577 
578         if (*last_blk - i + extra_bblks !=
579             BTOBB(be32_to_cpu(head->h_len)) + xhdrs)
580                 *last_blk = i;
581 
582 out:
583         xlog_put_bp(bp);
584         return error;
585 }
586 
587 /*
588  * Head is defined to be the point of the log where the next log write
589  * write could go.  This means that incomplete LR writes at the end are
590  * eliminated when calculating the head.  We aren't guaranteed that previous
591  * LR have complete transactions.  We only know that a cycle number of
592  * current cycle number -1 won't be present in the log if we start writing
593  * from our current block number.
594  *
595  * last_blk contains the block number of the first block with a given
596  * cycle number.
597  *
598  * Return: zero if normal, non-zero if error.
599  */
600 STATIC int
601 xlog_find_head(
602         xlog_t          *log,
603         xfs_daddr_t     *return_head_blk)
604 {
605         xfs_buf_t       *bp;
606         xfs_caddr_t     offset;
607         xfs_daddr_t     new_blk, first_blk, start_blk, last_blk, head_blk;
608         int             num_scan_bblks;
609         uint            first_half_cycle, last_half_cycle;
610         uint            stop_on_cycle;
611         int             error, log_bbnum = log->l_logBBsize;
612 
613         /* Is the end of the log device zeroed? */
614         if ((error = xlog_find_zeroed(log, &first_blk)) == -1) {
615                 *return_head_blk = first_blk;
616 
617                 /* Is the whole lot zeroed? */
618                 if (!first_blk) {
619                         /* Linux XFS shouldn't generate totally zeroed logs -
620                          * mkfs etc write a dummy unmount record to a fresh
621                          * log so we can store the uuid in there
622                          */
623                         xfs_warn(log->l_mp, "totally zeroed log");
624                 }
625 
626                 return 0;
627         } else if (error) {
628                 xfs_warn(log->l_mp, "empty log check failed");
629                 return error;
630         }
631 
632         first_blk = 0;                  /* get cycle # of 1st block */
633         bp = xlog_get_bp(log, 1);
634         if (!bp)
635                 return ENOMEM;
636 
637         error = xlog_bread(log, 0, 1, bp, &offset);
638         if (error)
639                 goto bp_err;
640 
641         first_half_cycle = xlog_get_cycle(offset);
642 
643         last_blk = head_blk = log_bbnum - 1;    /* get cycle # of last block */
644         error = xlog_bread(log, last_blk, 1, bp, &offset);
645         if (error)
646                 goto bp_err;
647 
648         last_half_cycle = xlog_get_cycle(offset);
649         ASSERT(last_half_cycle != 0);
650 
651         /*
652          * If the 1st half cycle number is equal to the last half cycle number,
653          * then the entire log is stamped with the same cycle number.  In this
654          * case, head_blk can't be set to zero (which makes sense).  The below
655          * math doesn't work out properly with head_blk equal to zero.  Instead,
656          * we set it to log_bbnum which is an invalid block number, but this
657          * value makes the math correct.  If head_blk doesn't changed through
658          * all the tests below, *head_blk is set to zero at the very end rather
659          * than log_bbnum.  In a sense, log_bbnum and zero are the same block
660          * in a circular file.
661          */
662         if (first_half_cycle == last_half_cycle) {
663                 /*
664                  * In this case we believe that the entire log should have
665                  * cycle number last_half_cycle.  We need to scan backwards
666                  * from the end verifying that there are no holes still
667                  * containing last_half_cycle - 1.  If we find such a hole,
668                  * then the start of that hole will be the new head.  The
669                  * simple case looks like
670                  *        x | x ... | x - 1 | x
671                  * Another case that fits this picture would be
672                  *        x | x + 1 | x ... | x
673                  * In this case the head really is somewhere at the end of the
674                  * log, as one of the latest writes at the beginning was
675                  * incomplete.
676                  * One more case is
677                  *        x | x + 1 | x ... | x - 1 | x
678                  * This is really the combination of the above two cases, and
679                  * the head has to end up at the start of the x-1 hole at the
680                  * end of the log.
681                  *
682                  * In the 256k log case, we will read from the beginning to the
683                  * end of the log and search for cycle numbers equal to x-1.
684                  * We don't worry about the x+1 blocks that we encounter,
685                  * because we know that they cannot be the head since the log
686                  * started with x.
687                  */
688                 head_blk = log_bbnum;
689                 stop_on_cycle = last_half_cycle - 1;
690         } else {
691                 /*
692                  * In this case we want to find the first block with cycle
693                  * number matching last_half_cycle.  We expect the log to be
694                  * some variation on
695                  *        x + 1 ... | x ... | x
696                  * The first block with cycle number x (last_half_cycle) will
697                  * be where the new head belongs.  First we do a binary search
698                  * for the first occurrence of last_half_cycle.  The binary
699                  * search may not be totally accurate, so then we scan back
700                  * from there looking for occurrences of last_half_cycle before
701                  * us.  If that backwards scan wraps around the beginning of
702                  * the log, then we look for occurrences of last_half_cycle - 1
703                  * at the end of the log.  The cases we're looking for look
704                  * like
705                  *                               v binary search stopped here
706                  *        x + 1 ... | x | x + 1 | x ... | x
707                  *                   ^ but we want to locate this spot
708                  * or
709                  *        <---------> less than scan distance
710                  *        x + 1 ... | x ... | x - 1 | x
711                  *                           ^ we want to locate this spot
712                  */
713                 stop_on_cycle = last_half_cycle;
714                 if ((error = xlog_find_cycle_start(log, bp, first_blk,
715                                                 &head_blk, last_half_cycle)))
716                         goto bp_err;
717         }
718 
719         /*
720          * Now validate the answer.  Scan back some number of maximum possible
721          * blocks and make sure each one has the expected cycle number.  The
722          * maximum is determined by the total possible amount of buffering
723          * in the in-core log.  The following number can be made tighter if
724          * we actually look at the block size of the filesystem.
725          */
726         num_scan_bblks = XLOG_TOTAL_REC_SHIFT(log);
727         if (head_blk >= num_scan_bblks) {
728                 /*
729                  * We are guaranteed that the entire check can be performed
730                  * in one buffer.
731                  */
732                 start_blk = head_blk - num_scan_bblks;
733                 if ((error = xlog_find_verify_cycle(log,
734                                                 start_blk, num_scan_bblks,
735                                                 stop_on_cycle, &new_blk)))
736                         goto bp_err;
737                 if (new_blk != -1)
738                         head_blk = new_blk;
739         } else {                /* need to read 2 parts of log */
740                 /*
741                  * We are going to scan backwards in the log in two parts.
742                  * First we scan the physical end of the log.  In this part
743                  * of the log, we are looking for blocks with cycle number
744                  * last_half_cycle - 1.
745                  * If we find one, then we know that the log starts there, as
746                  * we've found a hole that didn't get written in going around
747                  * the end of the physical log.  The simple case for this is
748                  *        x + 1 ... | x ... | x - 1 | x
749                  *        <---------> less than scan distance
750                  * If all of the blocks at the end of the log have cycle number
751                  * last_half_cycle, then we check the blocks at the start of
752                  * the log looking for occurrences of last_half_cycle.  If we
753                  * find one, then our current estimate for the location of the
754                  * first occurrence of last_half_cycle is wrong and we move
755                  * back to the hole we've found.  This case looks like
756                  *        x + 1 ... | x | x + 1 | x ...
757                  *                               ^ binary search stopped here
758                  * Another case we need to handle that only occurs in 256k
759                  * logs is
760                  *        x + 1 ... | x ... | x+1 | x ...
761                  *                   ^ binary search stops here
762                  * In a 256k log, the scan at the end of the log will see the
763                  * x + 1 blocks.  We need to skip past those since that is
764                  * certainly not the head of the log.  By searching for
765                  * last_half_cycle-1 we accomplish that.
766                  */
767                 ASSERT(head_blk <= INT_MAX &&
768                         (xfs_daddr_t) num_scan_bblks >= head_blk);
769                 start_blk = log_bbnum - (num_scan_bblks - head_blk);
770                 if ((error = xlog_find_verify_cycle(log, start_blk,
771                                         num_scan_bblks - (int)head_blk,
772                                         (stop_on_cycle - 1), &new_blk)))
773                         goto bp_err;
774                 if (new_blk != -1) {
775                         head_blk = new_blk;
776                         goto validate_head;
777                 }
778 
779                 /*
780                  * Scan beginning of log now.  The last part of the physical
781                  * log is good.  This scan needs to verify that it doesn't find
782                  * the last_half_cycle.
783                  */
784                 start_blk = 0;
785                 ASSERT(head_blk <= INT_MAX);
786                 if ((error = xlog_find_verify_cycle(log,
787                                         start_blk, (int)head_blk,
788                                         stop_on_cycle, &new_blk)))
789                         goto bp_err;
790                 if (new_blk != -1)
791                         head_blk = new_blk;
792         }
793 
794 validate_head:
795         /*
796          * Now we need to make sure head_blk is not pointing to a block in
797          * the middle of a log record.
798          */
799         num_scan_bblks = XLOG_REC_SHIFT(log);
800         if (head_blk >= num_scan_bblks) {
801                 start_blk = head_blk - num_scan_bblks; /* don't read head_blk */
802 
803                 /* start ptr at last block ptr before head_blk */
804                 if ((error = xlog_find_verify_log_record(log, start_blk,
805                                                         &head_blk, 0)) == -1) {
806                         error = XFS_ERROR(EIO);
807                         goto bp_err;
808                 } else if (error)
809                         goto bp_err;
810         } else {
811                 start_blk = 0;
812                 ASSERT(head_blk <= INT_MAX);
813                 if ((error = xlog_find_verify_log_record(log, start_blk,
814                                                         &head_blk, 0)) == -1) {
815                         /* We hit the beginning of the log during our search */
816                         start_blk = log_bbnum - (num_scan_bblks - head_blk);
817                         new_blk = log_bbnum;
818                         ASSERT(start_blk <= INT_MAX &&
819                                 (xfs_daddr_t) log_bbnum-start_blk >= 0);
820                         ASSERT(head_blk <= INT_MAX);
821                         if ((error = xlog_find_verify_log_record(log,
822                                                         start_blk, &new_blk,
823                                                         (int)head_blk)) == -1) {
824                                 error = XFS_ERROR(EIO);
825                                 goto bp_err;
826                         } else if (error)
827                                 goto bp_err;
828                         if (new_blk != log_bbnum)
829                                 head_blk = new_blk;
830                 } else if (error)
831                         goto bp_err;
832         }
833 
834         xlog_put_bp(bp);
835         if (head_blk == log_bbnum)
836                 *return_head_blk = 0;
837         else
838                 *return_head_blk = head_blk;
839         /*
840          * When returning here, we have a good block number.  Bad block
841          * means that during a previous crash, we didn't have a clean break
842          * from cycle number N to cycle number N-1.  In this case, we need
843          * to find the first block with cycle number N-1.
844          */
845         return 0;
846 
847  bp_err:
848         xlog_put_bp(bp);
849 
850         if (error)
851                 xfs_warn(log->l_mp, "failed to find log head");
852         return error;
853 }
854 
855 /*
856  * Find the sync block number or the tail of the log.
857  *
858  * This will be the block number of the last record to have its
859  * associated buffers synced to disk.  Every log record header has
860  * a sync lsn embedded in it.  LSNs hold block numbers, so it is easy
861  * to get a sync block number.  The only concern is to figure out which
862  * log record header to believe.
863  *
864  * The following algorithm uses the log record header with the largest
865  * lsn.  The entire log record does not need to be valid.  We only care
866  * that the header is valid.
867  *
868  * We could speed up search by using current head_blk buffer, but it is not
869  * available.
870  */
871 STATIC int
872 xlog_find_tail(
873         xlog_t                  *log,
874         xfs_daddr_t             *head_blk,
875         xfs_daddr_t             *tail_blk)
876 {
877         xlog_rec_header_t       *rhead;
878         xlog_op_header_t        *op_head;
879         xfs_caddr_t             offset = NULL;
880         xfs_buf_t               *bp;
881         int                     error, i, found;
882         xfs_daddr_t             umount_data_blk;
883         xfs_daddr_t             after_umount_blk;
884         xfs_lsn_t               tail_lsn;
885         int                     hblks;
886 
887         found = 0;
888 
889         /*
890          * Find previous log record
891          */
892         if ((error = xlog_find_head(log, head_blk)))
893                 return error;
894 
895         bp = xlog_get_bp(log, 1);
896         if (!bp)
897                 return ENOMEM;
898         if (*head_blk == 0) {                           /* special case */
899                 error = xlog_bread(log, 0, 1, bp, &offset);
900                 if (error)
901                         goto done;
902 
903                 if (xlog_get_cycle(offset) == 0) {
904                         *tail_blk = 0;
905                         /* leave all other log inited values alone */
906                         goto done;
907                 }
908         }
909 
910         /*
911          * Search backwards looking for log record header block
912          */
913         ASSERT(*head_blk < INT_MAX);
914         for (i = (int)(*head_blk) - 1; i >= 0; i--) {
915                 error = xlog_bread(log, i, 1, bp, &offset);
916                 if (error)
917                         goto done;
918 
919                 if (*(__be32 *)offset == cpu_to_be32(XLOG_HEADER_MAGIC_NUM)) {
920                         found = 1;
921                         break;
922                 }
923         }
924         /*
925          * If we haven't found the log record header block, start looking
926          * again from the end of the physical log.  XXXmiken: There should be
927          * a check here to make sure we didn't search more than N blocks in
928          * the previous code.
929          */
930         if (!found) {
931                 for (i = log->l_logBBsize - 1; i >= (int)(*head_blk); i--) {
932                         error = xlog_bread(log, i, 1, bp, &offset);
933                         if (error)
934                                 goto done;
935 
936                         if (*(__be32 *)offset ==
937                             cpu_to_be32(XLOG_HEADER_MAGIC_NUM)) {
938                                 found = 2;
939                                 break;
940                         }
941                 }
942         }
943         if (!found) {
944                 xfs_warn(log->l_mp, "%s: couldn't find sync record", __func__);
945                 ASSERT(0);
946                 return XFS_ERROR(EIO);
947         }
948 
949         /* find blk_no of tail of log */
950         rhead = (xlog_rec_header_t *)offset;
951         *tail_blk = BLOCK_LSN(be64_to_cpu(rhead->h_tail_lsn));
952 
953         /*
954          * Reset log values according to the state of the log when we
955          * crashed.  In the case where head_blk == 0, we bump curr_cycle
956          * one because the next write starts a new cycle rather than
957          * continuing the cycle of the last good log record.  At this
958          * point we have guaranteed that all partial log records have been
959          * accounted for.  Therefore, we know that the last good log record
960          * written was complete and ended exactly on the end boundary
961          * of the physical log.
962          */
963         log->l_prev_block = i;
964         log->l_curr_block = (int)*head_blk;
965         log->l_curr_cycle = be32_to_cpu(rhead->h_cycle);
966         if (found == 2)
967                 log->l_curr_cycle++;
968         atomic64_set(&log->l_tail_lsn, be64_to_cpu(rhead->h_tail_lsn));
969         atomic64_set(&log->l_last_sync_lsn, be64_to_cpu(rhead->h_lsn));
970         xlog_assign_grant_head(&log->l_grant_reserve_head, log->l_curr_cycle,
971                                         BBTOB(log->l_curr_block));
972         xlog_assign_grant_head(&log->l_grant_write_head, log->l_curr_cycle,
973                                         BBTOB(log->l_curr_block));
974 
975         /*
976          * Look for unmount record.  If we find it, then we know there
977          * was a clean unmount.  Since 'i' could be the last block in
978          * the physical log, we convert to a log block before comparing
979          * to the head_blk.
980          *
981          * Save the current tail lsn to use to pass to
982          * xlog_clear_stale_blocks() below.  We won't want to clear the
983          * unmount record if there is one, so we pass the lsn of the
984          * unmount record rather than the block after it.
985          */
986         if (xfs_sb_version_haslogv2(&log->l_mp->m_sb)) {
987                 int     h_size = be32_to_cpu(rhead->h_size);
988                 int     h_version = be32_to_cpu(rhead->h_version);
989 
990                 if ((h_version & XLOG_VERSION_2) &&
991                     (h_size > XLOG_HEADER_CYCLE_SIZE)) {
992                         hblks = h_size / XLOG_HEADER_CYCLE_SIZE;
993                         if (h_size % XLOG_HEADER_CYCLE_SIZE)
994                                 hblks++;
995                 } else {
996                         hblks = 1;
997                 }
998         } else {
999                 hblks = 1;
1000         }
1001         after_umount_blk = (i + hblks + (int)
1002                 BTOBB(be32_to_cpu(rhead->h_len))) % log->l_logBBsize;
1003         tail_lsn = atomic64_read(&log->l_tail_lsn);
1004         if (*head_blk == after_umount_blk &&
1005             be32_to_cpu(rhead->h_num_logops) == 1) {
1006                 umount_data_blk = (i + hblks) % log->l_logBBsize;
1007                 error = xlog_bread(log, umount_data_blk, 1, bp, &offset);
1008                 if (error)
1009                         goto done;
1010 
1011                 op_head = (xlog_op_header_t *)offset;
1012                 if (op_head->oh_flags & XLOG_UNMOUNT_TRANS) {
1013                         /*
1014                          * Set tail and last sync so that newly written
1015                          * log records will point recovery to after the
1016                          * current unmount record.
1017                          */
1018                         xlog_assign_atomic_lsn(&log->l_tail_lsn,
1019                                         log->l_curr_cycle, after_umount_blk);
1020                         xlog_assign_atomic_lsn(&log->l_last_sync_lsn,
1021                                         log->l_curr_cycle, after_umount_blk);
1022                         *tail_blk = after_umount_blk;
1023 
1024                         /*
1025                          * Note that the unmount was clean. If the unmount
1026                          * was not clean, we need to know this to rebuild the
1027                          * superblock counters from the perag headers if we
1028                          * have a filesystem using non-persistent counters.
1029                          */
1030                         log->l_mp->m_flags |= XFS_MOUNT_WAS_CLEAN;
1031                 }
1032         }
1033 
1034         /*
1035          * Make sure that there are no blocks in front of the head
1036          * with the same cycle number as the head.  This can happen
1037          * because we allow multiple outstanding log writes concurrently,
1038          * and the later writes might make it out before earlier ones.
1039          *
1040          * We use the lsn from before modifying it so that we'll never
1041          * overwrite the unmount record after a clean unmount.
1042          *
1043          * Do this only if we are going to recover the filesystem
1044          *
1045          * NOTE: This used to say "if (!readonly)"
1046          * However on Linux, we can & do recover a read-only filesystem.
1047          * We only skip recovery if NORECOVERY is specified on mount,
1048          * in which case we would not be here.
1049          *
1050          * But... if the -device- itself is readonly, just skip this.
1051          * We can't recover this device anyway, so it won't matter.
1052          */
1053         if (!xfs_readonly_buftarg(log->l_mp->m_logdev_targp))
1054                 error = xlog_clear_stale_blocks(log, tail_lsn);
1055 
1056 done:
1057         xlog_put_bp(bp);
1058 
1059         if (error)
1060                 xfs_warn(log->l_mp, "failed to locate log tail");
1061         return error;
1062 }
1063 
1064 /*
1065  * Is the log zeroed at all?
1066  *
1067  * The last binary search should be changed to perform an X block read
1068  * once X becomes small enough.  You can then search linearly through
1069  * the X blocks.  This will cut down on the number of reads we need to do.
1070  *
1071  * If the log is partially zeroed, this routine will pass back the blkno
1072  * of the first block with cycle number 0.  It won't have a complete LR
1073  * preceding it.
1074  *
1075  * Return:
1076  *      0  => the log is completely written to
1077  *      -1 => use *blk_no as the first block of the log
1078  *      >0 => error has occurred
1079  */
1080 STATIC int
1081 xlog_find_zeroed(
1082         xlog_t          *log,
1083         xfs_daddr_t     *blk_no)
1084 {
1085         xfs_buf_t       *bp;
1086         xfs_caddr_t     offset;
1087         uint            first_cycle, last_cycle;
1088         xfs_daddr_t     new_blk, last_blk, start_blk;
1089         xfs_daddr_t     num_scan_bblks;
1090         int             error, log_bbnum = log->l_logBBsize;
1091 
1092         *blk_no = 0;
1093 
1094         /* check totally zeroed log */
1095         bp = xlog_get_bp(log, 1);
1096         if (!bp)
1097                 return ENOMEM;
1098         error = xlog_bread(log, 0, 1, bp, &offset);
1099         if (error)
1100                 goto bp_err;
1101 
1102         first_cycle = xlog_get_cycle(offset);
1103         if (first_cycle == 0) {         /* completely zeroed log */
1104                 *blk_no = 0;
1105                 xlog_put_bp(bp);
1106                 return -1;
1107         }
1108 
1109         /* check partially zeroed log */
1110         error = xlog_bread(log, log_bbnum-1, 1, bp, &offset);
1111         if (error)
1112                 goto bp_err;
1113 
1114         last_cycle = xlog_get_cycle(offset);
1115         if (last_cycle != 0) {          /* log completely written to */
1116                 xlog_put_bp(bp);
1117                 return 0;
1118         } else if (first_cycle != 1) {
1119                 /*
1120                  * If the cycle of the last block is zero, the cycle of
1121                  * the first block must be 1. If it's not, maybe we're
1122                  * not looking at a log... Bail out.
1123                  */
1124                 xfs_warn(log->l_mp,
1125                         "Log inconsistent or not a log (last==0, first!=1)");
1126                 return XFS_ERROR(EINVAL);
1127         }
1128 
1129         /* we have a partially zeroed log */
1130         last_blk = log_bbnum-1;
1131         if ((error = xlog_find_cycle_start(log, bp, 0, &last_blk, 0)))
1132                 goto bp_err;
1133 
1134         /*
1135          * Validate the answer.  Because there is no way to guarantee that
1136          * the entire log is made up of log records which are the same size,
1137          * we scan over the defined maximum blocks.  At this point, the maximum
1138          * is not chosen to mean anything special.   XXXmiken
1139          */
1140         num_scan_bblks = XLOG_TOTAL_REC_SHIFT(log);
1141         ASSERT(num_scan_bblks <= INT_MAX);
1142 
1143         if (last_blk < num_scan_bblks)
1144                 num_scan_bblks = last_blk;
1145         start_blk = last_blk - num_scan_bblks;
1146 
1147         /*
1148          * We search for any instances of cycle number 0 that occur before
1149          * our current estimate of the head.  What we're trying to detect is
1150          *        1 ... | 0 | 1 | 0...
1151          *                       ^ binary search ends here
1152          */
1153         if ((error = xlog_find_verify_cycle(log, start_blk,
1154                                          (int)num_scan_bblks, 0, &new_blk)))
1155                 goto bp_err;
1156         if (new_blk != -1)
1157                 last_blk = new_blk;
1158 
1159         /*
1160          * Potentially backup over partial log record write.  We don't need
1161          * to search the end of the log because we know it is zero.
1162          */
1163         if ((error = xlog_find_verify_log_record(log, start_blk,
1164                                 &last_blk, 0)) == -1) {
1165             error = XFS_ERROR(EIO);
1166             goto bp_err;
1167         } else if (error)
1168             goto bp_err;
1169 
1170         *blk_no = last_blk;
1171 bp_err:
1172         xlog_put_bp(bp);
1173         if (error)
1174                 return error;
1175         return -1;
1176 }
1177 
1178 /*
1179  * These are simple subroutines used by xlog_clear_stale_blocks() below
1180  * to initialize a buffer full of empty log record headers and write
1181  * them into the log.
1182  */
1183 STATIC void
1184 xlog_add_record(
1185         xlog_t                  *log,
1186         xfs_caddr_t             buf,
1187         int                     cycle,
1188         int                     block,
1189         int                     tail_cycle,
1190         int                     tail_block)
1191 {
1192         xlog_rec_header_t       *recp = (xlog_rec_header_t *)buf;
1193 
1194         memset(buf, 0, BBSIZE);
1195         recp->h_magicno = cpu_to_be32(XLOG_HEADER_MAGIC_NUM);
1196         recp->h_cycle = cpu_to_be32(cycle);
1197         recp->h_version = cpu_to_be32(
1198                         xfs_sb_version_haslogv2(&log->l_mp->m_sb) ? 2 : 1);
1199         recp->h_lsn = cpu_to_be64(xlog_assign_lsn(cycle, block));
1200         recp->h_tail_lsn = cpu_to_be64(xlog_assign_lsn(tail_cycle, tail_block));
1201         recp->h_fmt = cpu_to_be32(XLOG_FMT);
1202         memcpy(&recp->h_fs_uuid, &log->l_mp->m_sb.sb_uuid, sizeof(uuid_t));
1203 }
1204 
1205 STATIC int
1206 xlog_write_log_records(
1207         xlog_t          *log,
1208         int             cycle,
1209         int             start_block,
1210         int             blocks,
1211         int             tail_cycle,
1212         int             tail_block)
1213 {
1214         xfs_caddr_t     offset;
1215         xfs_buf_t       *bp;
1216         int             balign, ealign;
1217         int             sectbb = log->l_sectBBsize;
1218         int             end_block = start_block + blocks;
1219         int             bufblks;
1220         int             error = 0;
1221         int             i, j = 0;
1222 
1223         /*
1224          * Greedily allocate a buffer big enough to handle the full
1225          * range of basic blocks to be written.  If that fails, try
1226          * a smaller size.  We need to be able to write at least a
1227          * log sector, or we're out of luck.
1228          */
1229         bufblks = 1 << ffs(blocks);
1230         while (!(bp = xlog_get_bp(log, bufblks))) {
1231                 bufblks >>= 1;
1232                 if (bufblks < sectbb)
1233                         return ENOMEM;
1234         }
1235 
1236         /* We may need to do a read at the start to fill in part of
1237          * the buffer in the starting sector not covered by the first
1238          * write below.
1239          */
1240         balign = round_down(start_block, sectbb);
1241         if (balign != start_block) {
1242                 error = xlog_bread_noalign(log, start_block, 1, bp);
1243                 if (error)
1244                         goto out_put_bp;
1245 
1246                 j = start_block - balign;
1247         }
1248 
1249         for (i = start_block; i < end_block; i += bufblks) {
1250                 int             bcount, endcount;
1251 
1252                 bcount = min(bufblks, end_block - start_block);
1253                 endcount = bcount - j;
1254 
1255                 /* We may need to do a read at the end to fill in part of
1256                  * the buffer in the final sector not covered by the write.
1257                  * If this is the same sector as the above read, skip it.
1258                  */
1259                 ealign = round_down(end_block, sectbb);
1260                 if (j == 0 && (start_block + endcount > ealign)) {
1261                         offset = bp->b_addr + BBTOB(ealign - start_block);
1262                         error = xlog_bread_offset(log, ealign, sectbb,
1263                                                         bp, offset);
1264                         if (error)
1265                                 break;
1266 
1267                 }
1268 
1269                 offset = xlog_align(log, start_block, endcount, bp);
1270                 for (; j < endcount; j++) {
1271                         xlog_add_record(log, offset, cycle, i+j,
1272                                         tail_cycle, tail_block);
1273                         offset += BBSIZE;
1274                 }
1275                 error = xlog_bwrite(log, start_block, endcount, bp);
1276                 if (error)
1277                         break;
1278                 start_block += endcount;
1279                 j = 0;
1280         }
1281 
1282  out_put_bp:
1283         xlog_put_bp(bp);
1284         return error;
1285 }
1286 
1287 /*
1288  * This routine is called to blow away any incomplete log writes out
1289  * in front of the log head.  We do this so that we won't become confused
1290  * if we come up, write only a little bit more, and then crash again.
1291  * If we leave the partial log records out there, this situation could
1292  * cause us to think those partial writes are valid blocks since they
1293  * have the current cycle number.  We get rid of them by overwriting them
1294  * with empty log records with the old cycle number rather than the
1295  * current one.
1296  *
1297  * The tail lsn is passed in rather than taken from
1298  * the log so that we will not write over the unmount record after a
1299  * clean unmount in a 512 block log.  Doing so would leave the log without
1300  * any valid log records in it until a new one was written.  If we crashed
1301  * during that time we would not be able to recover.
1302  */
1303 STATIC int
1304 xlog_clear_stale_blocks(
1305         xlog_t          *log,
1306         xfs_lsn_t       tail_lsn)
1307 {
1308         int             tail_cycle, head_cycle;
1309         int             tail_block, head_block;
1310         int             tail_distance, max_distance;
1311         int             distance;
1312         int             error;
1313 
1314         tail_cycle = CYCLE_LSN(tail_lsn);
1315         tail_block = BLOCK_LSN(tail_lsn);
1316         head_cycle = log->l_curr_cycle;
1317         head_block = log->l_curr_block;
1318 
1319         /*
1320          * Figure out the distance between the new head of the log
1321          * and the tail.  We want to write over any blocks beyond the
1322          * head that we may have written just before the crash, but
1323          * we don't want to overwrite the tail of the log.
1324          */
1325         if (head_cycle == tail_cycle) {
1326                 /*
1327                  * The tail is behind the head in the physical log,
1328                  * so the distance from the head to the tail is the
1329                  * distance from the head to the end of the log plus
1330                  * the distance from the beginning of the log to the
1331                  * tail.
1332                  */
1333                 if (unlikely(head_block < tail_block || head_block >= log->l_logBBsize)) {
1334                         XFS_ERROR_REPORT("xlog_clear_stale_blocks(1)",
1335                                          XFS_ERRLEVEL_LOW, log->l_mp);
1336                         return XFS_ERROR(EFSCORRUPTED);
1337                 }
1338                 tail_distance = tail_block + (log->l_logBBsize - head_block);
1339         } else {
1340                 /*
1341                  * The head is behind the tail in the physical log,
1342                  * so the distance from the head to the tail is just
1343                  * the tail block minus the head block.
1344                  */
1345                 if (unlikely(head_block >= tail_block || head_cycle != (tail_cycle + 1))){
1346                         XFS_ERROR_REPORT("xlog_clear_stale_blocks(2)",
1347                                          XFS_ERRLEVEL_LOW, log->l_mp);
1348                         return XFS_ERROR(EFSCORRUPTED);
1349                 }
1350                 tail_distance = tail_block - head_block;
1351         }
1352 
1353         /*
1354          * If the head is right up against the tail, we can't clear
1355          * anything.
1356          */
1357         if (tail_distance <= 0) {
1358                 ASSERT(tail_distance == 0);
1359                 return 0;
1360         }
1361 
1362         max_distance = XLOG_TOTAL_REC_SHIFT(log);
1363         /*
1364          * Take the smaller of the maximum amount of outstanding I/O
1365          * we could have and the distance to the tail to clear out.
1366          * We take the smaller so that we don't overwrite the tail and
1367          * we don't waste all day writing from the head to the tail
1368          * for no reason.
1369          */
1370         max_distance = MIN(max_distance, tail_distance);
1371 
1372         if ((head_block + max_distance) <= log->l_logBBsize) {
1373                 /*
1374                  * We can stomp all the blocks we need to without
1375                  * wrapping around the end of the log.  Just do it
1376                  * in a single write.  Use the cycle number of the
1377                  * current cycle minus one so that the log will look like:
1378                  *     n ... | n - 1 ...
1379                  */
1380                 error = xlog_write_log_records(log, (head_cycle - 1),
1381                                 head_block, max_distance, tail_cycle,
1382                                 tail_block);
1383                 if (error)
1384                         return error;
1385         } else {
1386                 /*
1387                  * We need to wrap around the end of the physical log in
1388                  * order to clear all the blocks.  Do it in two separate
1389                  * I/Os.  The first write should be from the head to the
1390                  * end of the physical log, and it should use the current
1391                  * cycle number minus one just like above.
1392                  */
1393                 distance = log->l_logBBsize - head_block;
1394                 error = xlog_write_log_records(log, (head_cycle - 1),
1395                                 head_block, distance, tail_cycle,
1396                                 tail_block);
1397 
1398                 if (error)
1399                         return error;
1400 
1401                 /*
1402                  * Now write the blocks at the start of the physical log.
1403                  * This writes the remainder of the blocks we want to clear.
1404                  * It uses the current cycle number since we're now on the
1405                  * same cycle as the head so that we get:
1406                  *    n ... n ... | n - 1 ...
1407                  *    ^^^^^ blocks we're writing
1408                  */
1409                 distance = max_distance - (log->l_logBBsize - head_block);
1410                 error = xlog_write_log_records(log, head_cycle, 0, distance,
1411                                 tail_cycle, tail_block);
1412                 if (error)
1413                         return error;
1414         }
1415 
1416         return 0;
1417 }
1418 
1419 /******************************************************************************
1420  *
1421  *              Log recover routines
1422  *
1423  ******************************************************************************
1424  */
1425 
1426 STATIC xlog_recover_t *
1427 xlog_recover_find_tid(
1428         struct hlist_head       *head,
1429         xlog_tid_t              tid)
1430 {
1431         xlog_recover_t          *trans;
1432         struct hlist_node       *n;
1433 
1434         hlist_for_each_entry(trans, n, head, r_list) {
1435                 if (trans->r_log_tid == tid)
1436                         return trans;
1437         }
1438         return NULL;
1439 }
1440 
1441 STATIC void
1442 xlog_recover_new_tid(
1443         struct hlist_head       *head,
1444         xlog_tid_t              tid,
1445         xfs_lsn_t               lsn)
1446 {
1447         xlog_recover_t          *trans;
1448 
1449         trans = kmem_zalloc(sizeof(xlog_recover_t), KM_SLEEP);
1450         trans->r_log_tid   = tid;
1451         trans->r_lsn       = lsn;
1452         INIT_LIST_HEAD(&trans->r_itemq);
1453 
1454         INIT_HLIST_NODE(&trans->r_list);
1455         hlist_add_head(&trans->r_list, head);
1456 }
1457 
1458 STATIC void
1459 xlog_recover_add_item(
1460         struct list_head        *head)
1461 {
1462         xlog_recover_item_t     *item;
1463 
1464         item = kmem_zalloc(sizeof(xlog_recover_item_t), KM_SLEEP);
1465         INIT_LIST_HEAD(&item->ri_list);
1466         list_add_tail(&item->ri_list, head);
1467 }
1468 
1469 STATIC int
1470 xlog_recover_add_to_cont_trans(
1471         struct log              *log,
1472         xlog_recover_t          *trans,
1473         xfs_caddr_t             dp,
1474         int                     len)
1475 {
1476         xlog_recover_item_t     *item;
1477         xfs_caddr_t             ptr, old_ptr;
1478         int                     old_len;
1479 
1480         if (list_empty(&trans->r_itemq)) {
1481                 /* finish copying rest of trans header */
1482                 xlog_recover_add_item(&trans->r_itemq);
1483                 ptr = (xfs_caddr_t) &trans->r_theader +
1484                                 sizeof(xfs_trans_header_t) - len;
1485                 memcpy(ptr, dp, len); /* d, s, l */
1486                 return 0;
1487         }
1488         /* take the tail entry */
1489         item = list_entry(trans->r_itemq.prev, xlog_recover_item_t, ri_list);
1490 
1491         old_ptr = item->ri_buf[item->ri_cnt-1].i_addr;
1492         old_len = item->ri_buf[item->ri_cnt-1].i_len;
1493 
1494         ptr = kmem_realloc(old_ptr, len+old_len, old_len, 0u);
1495         memcpy(&ptr[old_len], dp, len); /* d, s, l */
1496         item->ri_buf[item->ri_cnt-1].i_len += len;
1497         item->ri_buf[item->ri_cnt-1].i_addr = ptr;
1498         trace_xfs_log_recover_item_add_cont(log, trans, item, 0);
1499         return 0;
1500 }
1501 
1502 /*
1503  * The next region to add is the start of a new region.  It could be
1504  * a whole region or it could be the first part of a new region.  Because
1505  * of this, the assumption here is that the type and size fields of all
1506  * format structures fit into the first 32 bits of the structure.
1507  *
1508  * This works because all regions must be 32 bit aligned.  Therefore, we
1509  * either have both fields or we have neither field.  In the case we have
1510  * neither field, the data part of the region is zero length.  We only have
1511  * a log_op_header and can throw away the header since a new one will appear
1512  * later.  If we have at least 4 bytes, then we can determine how many regions
1513  * will appear in the current log item.
1514  */
1515 STATIC int
1516 xlog_recover_add_to_trans(
1517         struct log              *log,
1518         xlog_recover_t          *trans,
1519         xfs_caddr_t             dp,
1520         int                     len)
1521 {
1522         xfs_inode_log_format_t  *in_f;                  /* any will do */
1523         xlog_recover_item_t     *item;
1524         xfs_caddr_t             ptr;
1525 
1526         if (!len)
1527                 return 0;
1528         if (list_empty(&trans->r_itemq)) {
1529                 /* we need to catch log corruptions here */
1530                 if (*(uint *)dp != XFS_TRANS_HEADER_MAGIC) {
1531                         xfs_warn(log->l_mp, "%s: bad header magic number",
1532                                 __func__);
1533                         ASSERT(0);
1534                         return XFS_ERROR(EIO);
1535                 }
1536                 if (len == sizeof(xfs_trans_header_t))
1537                         xlog_recover_add_item(&trans->r_itemq);
1538                 memcpy(&trans->r_theader, dp, len); /* d, s, l */
1539                 return 0;
1540         }
1541 
1542         ptr = kmem_alloc(len, KM_SLEEP);
1543         memcpy(ptr, dp, len);
1544         in_f = (xfs_inode_log_format_t *)ptr;
1545 
1546         /* take the tail entry */
1547         item = list_entry(trans->r_itemq.prev, xlog_recover_item_t, ri_list);
1548         if (item->ri_total != 0 &&
1549              item->ri_total == item->ri_cnt) {
1550                 /* tail item is in use, get a new one */
1551                 xlog_recover_add_item(&trans->r_itemq);
1552                 item = list_entry(trans->r_itemq.prev,
1553                                         xlog_recover_item_t, ri_list);
1554         }
1555 
1556         if (item->ri_total == 0) {              /* first region to be added */
1557                 if (in_f->ilf_size == 0 ||
1558                     in_f->ilf_size > XLOG_MAX_REGIONS_IN_ITEM) {
1559                         xfs_warn(log->l_mp,
1560                 "bad number of regions (%d) in inode log format",
1561                                   in_f->ilf_size);
1562                         ASSERT(0);
1563                         return XFS_ERROR(EIO);
1564                 }
1565 
1566                 item->ri_total = in_f->ilf_size;
1567                 item->ri_buf =
1568                         kmem_zalloc(item->ri_total * sizeof(xfs_log_iovec_t),
1569                                     KM_SLEEP);
1570         }
1571         ASSERT(item->ri_total > item->ri_cnt);
1572         /* Description region is ri_buf[0] */
1573         item->ri_buf[item->ri_cnt].i_addr = ptr;
1574         item->ri_buf[item->ri_cnt].i_len  = len;
1575         item->ri_cnt++;
1576         trace_xfs_log_recover_item_add(log, trans, item, 0);
1577         return 0;
1578 }
1579 
1580 /*
1581  * Sort the log items in the transaction. Cancelled buffers need
1582  * to be put first so they are processed before any items that might
1583  * modify the buffers. If they are cancelled, then the modifications
1584  * don't need to be replayed.
1585  */
1586 STATIC int
1587 xlog_recover_reorder_trans(
1588         struct log              *log,
1589         xlog_recover_t          *trans,
1590         int                     pass)
1591 {
1592         xlog_recover_item_t     *item, *n;
1593         LIST_HEAD(sort_list);
1594 
1595         list_splice_init(&trans->r_itemq, &sort_list);
1596         list_for_each_entry_safe(item, n, &sort_list, ri_list) {
1597                 xfs_buf_log_format_t    *buf_f = item->ri_buf[0].i_addr;
1598 
1599                 switch (ITEM_TYPE(item)) {
1600                 case XFS_LI_BUF:
1601                         if (!(buf_f->blf_flags & XFS_BLF_CANCEL)) {
1602                                 trace_xfs_log_recover_item_reorder_head(log,
1603                                                         trans, item, pass);
1604                                 list_move(&item->ri_list, &trans->r_itemq);
1605                                 break;
1606                         }
1607                 case XFS_LI_INODE:
1608                 case XFS_LI_DQUOT:
1609                 case XFS_LI_QUOTAOFF:
1610                 case XFS_LI_EFD:
1611                 case XFS_LI_EFI:
1612                         trace_xfs_log_recover_item_reorder_tail(log,
1613                                                         trans, item, pass);
1614                         list_move_tail(&item->ri_list, &trans->r_itemq);
1615                         break;
1616                 default:
1617                         xfs_warn(log->l_mp,
1618                                 "%s: unrecognized type of log operation",
1619                                 __func__);
1620                         ASSERT(0);
1621                         return XFS_ERROR(EIO);
1622                 }
1623         }
1624         ASSERT(list_empty(&sort_list));
1625         return 0;
1626 }
1627 
1628 /*
1629  * Build up the table of buf cancel records so that we don't replay
1630  * cancelled data in the second pass.  For buffer records that are
1631  * not cancel records, there is nothing to do here so we just return.
1632  *
1633  * If we get a cancel record which is already in the table, this indicates
1634  * that the buffer was cancelled multiple times.  In order to ensure
1635  * that during pass 2 we keep the record in the table until we reach its
1636  * last occurrence in the log, we keep a reference count in the cancel
1637  * record in the table to tell us how many times we expect to see this
1638  * record during the second pass.
1639  */
1640 STATIC int
1641 xlog_recover_buffer_pass1(
1642         struct log              *log,
1643         xlog_recover_item_t     *item)
1644 {
1645         xfs_buf_log_format_t    *buf_f = item->ri_buf[0].i_addr;
1646         struct list_head        *bucket;
1647         struct xfs_buf_cancel   *bcp;
1648 
1649         /*
1650          * If this isn't a cancel buffer item, then just return.
1651          */
1652         if (!(buf_f->blf_flags & XFS_BLF_CANCEL)) {
1653                 trace_xfs_log_recover_buf_not_cancel(log, buf_f);
1654                 return 0;
1655         }
1656 
1657         /*
1658          * Insert an xfs_buf_cancel record into the hash table of them.
1659          * If there is already an identical record, bump its reference count.
1660          */
1661         bucket = XLOG_BUF_CANCEL_BUCKET(log, buf_f->blf_blkno);
1662         list_for_each_entry(bcp, bucket, bc_list) {
1663                 if (bcp->bc_blkno == buf_f->blf_blkno &&
1664                     bcp->bc_len == buf_f->blf_len) {
1665                         bcp->bc_refcount++;
1666                         trace_xfs_log_recover_buf_cancel_ref_inc(log, buf_f);
1667                         return 0;
1668                 }
1669         }
1670 
1671         bcp = kmem_alloc(sizeof(struct xfs_buf_cancel), KM_SLEEP);
1672         bcp->bc_blkno = buf_f->blf_blkno;
1673         bcp->bc_len = buf_f->blf_len;
1674         bcp->bc_refcount = 1;
1675         list_add_tail(&bcp->bc_list, bucket);
1676 
1677         trace_xfs_log_recover_buf_cancel_add(log, buf_f);
1678         return 0;
1679 }
1680 
1681 /*
1682  * Check to see whether the buffer being recovered has a corresponding
1683  * entry in the buffer cancel record table.  If it does then return 1
1684  * so that it will be cancelled, otherwise return 0.  If the buffer is
1685  * actually a buffer cancel item (XFS_BLF_CANCEL is set), then decrement
1686  * the refcount on the entry in the table and remove it from the table
1687  * if this is the last reference.
1688  *
1689  * We remove the cancel record from the table when we encounter its
1690  * last occurrence in the log so that if the same buffer is re-used
1691  * again after its last cancellation we actually replay the changes
1692  * made at that point.
1693  */
1694 STATIC int
1695 xlog_check_buffer_cancelled(
1696         struct log              *log,
1697         xfs_daddr_t             blkno,
1698         uint                    len,
1699         ushort                  flags)
1700 {
1701         struct list_head        *bucket;
1702         struct xfs_buf_cancel   *bcp;
1703 
1704         if (log->l_buf_cancel_table == NULL) {
1705                 /*
1706                  * There is nothing in the table built in pass one,
1707                  * so this buffer must not be cancelled.
1708                  */
1709                 ASSERT(!(flags & XFS_BLF_CANCEL));
1710                 return 0;
1711         }
1712 
1713         /*
1714          * Search for an entry in the  cancel table that matches our buffer.
1715          */
1716         bucket = XLOG_BUF_CANCEL_BUCKET(log, blkno);
1717         list_for_each_entry(bcp, bucket, bc_list) {
1718                 if (bcp->bc_blkno == blkno && bcp->bc_len == len)
1719                         goto found;
1720         }
1721 
1722         /*
1723          * We didn't find a corresponding entry in the table, so return 0 so
1724          * that the buffer is NOT cancelled.
1725          */
1726         ASSERT(!(flags & XFS_BLF_CANCEL));
1727         return 0;
1728 
1729 found:
1730         /*
1731          * We've go a match, so return 1 so that the recovery of this buffer
1732          * is cancelled.  If this buffer is actually a buffer cancel log
1733          * item, then decrement the refcount on the one in the table and
1734          * remove it if this is the last reference.
1735          */
1736         if (flags & XFS_BLF_CANCEL) {
1737                 if (--bcp->bc_refcount == 0) {
1738                         list_del(&bcp->bc_list);
1739                         kmem_free(bcp);
1740                 }
1741         }
1742         return 1;
1743 }
1744 
1745 /*
1746  * Perform recovery for a buffer full of inodes.  In these buffers, the only
1747  * data which should be recovered is that which corresponds to the
1748  * di_next_unlinked pointers in the on disk inode structures.  The rest of the
1749  * data for the inodes is always logged through the inodes themselves rather
1750  * than the inode buffer and is recovered in xlog_recover_inode_pass2().
1751  *
1752  * The only time when buffers full of inodes are fully recovered is when the
1753  * buffer is full of newly allocated inodes.  In this case the buffer will
1754  * not be marked as an inode buffer and so will be sent to
1755  * xlog_recover_do_reg_buffer() below during recovery.
1756  */
1757 STATIC int
1758 xlog_recover_do_inode_buffer(
1759         struct xfs_mount        *mp,
1760         xlog_recover_item_t     *item,
1761         struct xfs_buf          *bp,
1762         xfs_buf_log_format_t    *buf_f)
1763 {
1764         int                     i;
1765         int                     item_index = 0;
1766         int                     bit = 0;
1767         int                     nbits = 0;
1768         int                     reg_buf_offset = 0;
1769         int                     reg_buf_bytes = 0;
1770         int                     next_unlinked_offset;
1771         int                     inodes_per_buf;
1772         xfs_agino_t             *logged_nextp;
1773         xfs_agino_t             *buffer_nextp;
1774 
1775         trace_xfs_log_recover_buf_inode_buf(mp->m_log, buf_f);
1776 
1777         inodes_per_buf = XFS_BUF_COUNT(bp) >> mp->m_sb.sb_inodelog;
1778         for (i = 0; i < inodes_per_buf; i++) {
1779                 next_unlinked_offset = (i * mp->m_sb.sb_inodesize) +
1780                         offsetof(xfs_dinode_t, di_next_unlinked);
1781 
1782                 while (next_unlinked_offset >=
1783                        (reg_buf_offset + reg_buf_bytes)) {
1784                         /*
1785                          * The next di_next_unlinked field is beyond
1786                          * the current logged region.  Find the next
1787                          * logged region that contains or is beyond
1788                          * the current di_next_unlinked field.
1789                          */
1790                         bit += nbits;
1791                         bit = xfs_next_bit(buf_f->blf_data_map,
1792                                            buf_f->blf_map_size, bit);
1793 
1794                         /*
1795                          * If there are no more logged regions in the
1796                          * buffer, then we're done.
1797                          */
1798                         if (bit == -1)
1799                                 return 0;
1800 
1801                         nbits = xfs_contig_bits(buf_f->blf_data_map,
1802                                                 buf_f->blf_map_size, bit);
1803                         ASSERT(nbits > 0);
1804                         reg_buf_offset = bit << XFS_BLF_SHIFT;
1805                         reg_buf_bytes = nbits << XFS_BLF_SHIFT;
1806                         item_index++;
1807                 }
1808 
1809                 /*
1810                  * If the current logged region starts after the current
1811                  * di_next_unlinked field, then move on to the next
1812                  * di_next_unlinked field.
1813                  */
1814                 if (next_unlinked_offset < reg_buf_offset)
1815                         continue;
1816 
1817                 ASSERT(item->ri_buf[item_index].i_addr != NULL);
1818                 ASSERT((item->ri_buf[item_index].i_len % XFS_BLF_CHUNK) == 0);
1819                 ASSERT((reg_buf_offset + reg_buf_bytes) <= XFS_BUF_COUNT(bp));
1820 
1821                 /*
1822                  * The current logged region contains a copy of the
1823                  * current di_next_unlinked field.  Extract its value
1824                  * and copy it to the buffer copy.
1825                  */
1826                 logged_nextp = item->ri_buf[item_index].i_addr +
1827                                 next_unlinked_offset - reg_buf_offset;
1828                 if (unlikely(*logged_nextp == 0)) {
1829                         xfs_alert(mp,
1830                 "Bad inode buffer log record (ptr = 0x%p, bp = 0x%p). "
1831                 "Trying to replay bad (0) inode di_next_unlinked field.",
1832                                 item, bp);
1833                         XFS_ERROR_REPORT("xlog_recover_do_inode_buf",
1834                                          XFS_ERRLEVEL_LOW, mp);
1835                         return XFS_ERROR(EFSCORRUPTED);
1836                 }
1837 
1838                 buffer_nextp = (xfs_agino_t *)xfs_buf_offset(bp,
1839                                               next_unlinked_offset);
1840                 *buffer_nextp = *logged_nextp;
1841         }
1842 
1843         return 0;
1844 }
1845 
1846 /*
1847  * Perform a 'normal' buffer recovery.  Each logged region of the
1848  * buffer should be copied over the corresponding region in the
1849  * given buffer.  The bitmap in the buf log format structure indicates
1850  * where to place the logged data.
1851  */
1852 STATIC void
1853 xlog_recover_do_reg_buffer(
1854         struct xfs_mount        *mp,
1855         xlog_recover_item_t     *item,
1856         struct xfs_buf          *bp,
1857         xfs_buf_log_format_t    *buf_f)
1858 {
1859         int                     i;
1860         int                     bit;
1861         int                     nbits;
1862         int                     error;
1863 
1864         trace_xfs_log_recover_buf_reg_buf(mp->m_log, buf_f);
1865 
1866         bit = 0;
1867         i = 1;  /* 0 is the buf format structure */
1868         while (1) {
1869                 bit = xfs_next_bit(buf_f->blf_data_map,
1870                                    buf_f->blf_map_size, bit);
1871                 if (bit == -1)
1872                         break;
1873                 nbits = xfs_contig_bits(buf_f->blf_data_map,
1874                                         buf_f->blf_map_size, bit);
1875                 ASSERT(nbits > 0);
1876                 ASSERT(item->ri_buf[i].i_addr != NULL);
1877                 ASSERT(item->ri_buf[i].i_len % XFS_BLF_CHUNK == 0);
1878                 ASSERT(XFS_BUF_COUNT(bp) >=
1879                        ((uint)bit << XFS_BLF_SHIFT)+(nbits<<XFS_BLF_SHIFT));
1880 
1881                 /*
1882                  * Do a sanity check if this is a dquot buffer. Just checking
1883                  * the first dquot in the buffer should do. XXXThis is
1884                  * probably a good thing to do for other buf types also.
1885                  */
1886                 error = 0;
1887                 if (buf_f->blf_flags &
1888                    (XFS_BLF_UDQUOT_BUF|XFS_BLF_PDQUOT_BUF|XFS_BLF_GDQUOT_BUF)) {
1889                         if (item->ri_buf[i].i_addr == NULL) {
1890                                 xfs_alert(mp,
1891                                         "XFS: NULL dquot in %s.", __func__);
1892                                 goto next;
1893                         }
1894                         if (item->ri_buf[i].i_len < sizeof(xfs_disk_dquot_t)) {
1895                                 xfs_alert(mp,
1896                                         "XFS: dquot too small (%d) in %s.",
1897                                         item->ri_buf[i].i_len, __func__);
1898                                 goto next;
1899                         }
1900                         error = xfs_qm_dqcheck(mp, item->ri_buf[i].i_addr,
1901                                                -1, 0, XFS_QMOPT_DOWARN,
1902                                                "dquot_buf_recover");
1903                         if (error)
1904                                 goto next;
1905                 }
1906 
1907                 memcpy(xfs_buf_offset(bp,
1908                         (uint)bit << XFS_BLF_SHIFT),    /* dest */
1909                         item->ri_buf[i].i_addr,         /* source */
1910                         nbits<<XFS_BLF_SHIFT);          /* length */
1911  next:
1912                 i++;
1913                 bit += nbits;
1914         }
1915 
1916         /* Shouldn't be any more regions */
1917         ASSERT(i == item->ri_total);
1918 }
1919 
1920 /*
1921  * Do some primitive error checking on ondisk dquot data structures.
1922  */
1923 int
1924 xfs_qm_dqcheck(
1925         struct xfs_mount *mp,
1926         xfs_disk_dquot_t *ddq,
1927         xfs_dqid_t       id,
1928         uint             type,    /* used only when IO_dorepair is true */
1929         uint             flags,
1930         char             *str)
1931 {
1932         xfs_dqblk_t      *d = (xfs_dqblk_t *)ddq;
1933         int             errs = 0;
1934 
1935         /*
1936          * We can encounter an uninitialized dquot buffer for 2 reasons:
1937          * 1. If we crash while deleting the quotainode(s), and those blks got
1938          *    used for user data. This is because we take the path of regular
1939          *    file deletion; however, the size field of quotainodes is never
1940          *    updated, so all the tricks that we play in itruncate_finish
1941          *    don't quite matter.
1942          *
1943          * 2. We don't play the quota buffers when there's a quotaoff logitem.
1944          *    But the allocation will be replayed so we'll end up with an
1945          *    uninitialized quota block.
1946          *
1947          * This is all fine; things are still consistent, and we haven't lost
1948          * any quota information. Just don't complain about bad dquot blks.
1949          */
1950         if (ddq->d_magic != cpu_to_be16(XFS_DQUOT_MAGIC)) {
1951                 if (flags & XFS_QMOPT_DOWARN)
1952                         xfs_alert(mp,
1953                         "%s : XFS dquot ID 0x%x, magic 0x%x != 0x%x",
1954                         str, id, be16_to_cpu(ddq->d_magic), XFS_DQUOT_MAGIC);
1955                 errs++;
1956         }
1957         if (ddq->d_version != XFS_DQUOT_VERSION) {
1958                 if (flags & XFS_QMOPT_DOWARN)
1959                         xfs_alert(mp,
1960                         "%s : XFS dquot ID 0x%x, version 0x%x != 0x%x",
1961                         str, id, ddq->d_version, XFS_DQUOT_VERSION);
1962                 errs++;
1963         }
1964 
1965         if (ddq->d_flags != XFS_DQ_USER &&
1966             ddq->d_flags != XFS_DQ_PROJ &&
1967             ddq->d_flags != XFS_DQ_GROUP) {
1968                 if (flags & XFS_QMOPT_DOWARN)
1969                         xfs_alert(mp,
1970                         "%s : XFS dquot ID 0x%x, unknown flags 0x%x",
1971                         str, id, ddq->d_flags);
1972                 errs++;
1973         }
1974 
1975         if (id != -1 && id != be32_to_cpu(ddq->d_id)) {
1976                 if (flags & XFS_QMOPT_DOWARN)
1977                         xfs_alert(mp,
1978                         "%s : ondisk-dquot 0x%p, ID mismatch: "
1979                         "0x%x expected, found id 0x%x",
1980                         str, ddq, id, be32_to_cpu(ddq->d_id));
1981                 errs++;
1982         }
1983 
1984         if (!errs && ddq->d_id) {
1985                 if (ddq->d_blk_softlimit &&
1986                     be64_to_cpu(ddq->d_bcount) >=
1987                                 be64_to_cpu(ddq->d_blk_softlimit)) {
1988                         if (!ddq->d_btimer) {
1989                                 if (flags & XFS_QMOPT_DOWARN)
1990                                         xfs_alert(mp,
1991                         "%s : Dquot ID 0x%x (0x%p) BLK TIMER NOT STARTED",
1992                                         str, (int)be32_to_cpu(ddq->d_id), ddq);
1993                                 errs++;
1994                         }
1995                 }
1996                 if (ddq->d_ino_softlimit &&
1997                     be64_to_cpu(ddq->d_icount) >=
1998                                 be64_to_cpu(ddq->d_ino_softlimit)) {
1999                         if (!ddq->d_itimer) {
2000                                 if (flags & XFS_QMOPT_DOWARN)
2001                                         xfs_alert(mp,
2002                         "%s : Dquot ID 0x%x (0x%p) INODE TIMER NOT STARTED",
2003                                         str, (int)be32_to_cpu(ddq->d_id), ddq);
2004                                 errs++;
2005                         }
2006                 }
2007                 if (ddq->d_rtb_softlimit &&
2008                     be64_to_cpu(ddq->d_rtbcount) >=
2009                                 be64_to_cpu(ddq->d_rtb_softlimit)) {
2010                         if (!ddq->d_rtbtimer) {
2011                                 if (flags & XFS_QMOPT_DOWARN)
2012                                         xfs_alert(mp,
2013                         "%s : Dquot ID 0x%x (0x%p) RTBLK TIMER NOT STARTED",
2014                                         str, (int)be32_to_cpu(ddq->d_id), ddq);
2015                                 errs++;
2016                         }
2017                 }
2018         }
2019 
2020         if (!errs || !(flags & XFS_QMOPT_DQREPAIR))
2021                 return errs;
2022 
2023         if (flags & XFS_QMOPT_DOWARN)
2024                 xfs_notice(mp, "Re-initializing dquot ID 0x%x", id);
2025 
2026         /*
2027          * Typically, a repair is only requested by quotacheck.
2028          */
2029         ASSERT(id != -1);
2030         ASSERT(flags & XFS_QMOPT_DQREPAIR);
2031         memset(d, 0, sizeof(xfs_dqblk_t));
2032 
2033         d->dd_diskdq.d_magic = cpu_to_be16(XFS_DQUOT_MAGIC);
2034         d->dd_diskdq.d_version = XFS_DQUOT_VERSION;
2035         d->dd_diskdq.d_flags = type;
2036         d->dd_diskdq.d_id = cpu_to_be32(id);
2037 
2038         return errs;
2039 }
2040 
2041 /*
2042  * Perform a dquot buffer recovery.
2043  * Simple algorithm: if we have found a QUOTAOFF logitem of the same type
2044  * (ie. USR or GRP), then just toss this buffer away; don't recover it.
2045  * Else, treat it as a regular buffer and do recovery.
2046  */
2047 STATIC void
2048 xlog_recover_do_dquot_buffer(
2049         xfs_mount_t             *mp,
2050         xlog_t                  *log,
2051         xlog_recover_item_t     *item,
2052         xfs_buf_t               *bp,
2053         xfs_buf_log_format_t    *buf_f)
2054 {
2055         uint                    type;
2056 
2057         trace_xfs_log_recover_buf_dquot_buf(log, buf_f);
2058 
2059         /*
2060          * Filesystems are required to send in quota flags at mount time.
2061          */
2062         if (mp->m_qflags == 0) {
2063                 return;
2064         }
2065 
2066         type = 0;
2067         if (buf_f->blf_flags & XFS_BLF_UDQUOT_BUF)
2068                 type |= XFS_DQ_USER;
2069         if (buf_f->blf_flags & XFS_BLF_PDQUOT_BUF)
2070                 type |= XFS_DQ_PROJ;
2071         if (buf_f->blf_flags & XFS_BLF_GDQUOT_BUF)
2072                 type |= XFS_DQ_GROUP;
2073         /*
2074          * This type of quotas was turned off, so ignore this buffer
2075          */
2076         if (log->l_quotaoffs_flag & type)
2077                 return;
2078 
2079         xlog_recover_do_reg_buffer(mp, item, bp, buf_f);
2080 }
2081 
2082 /*
2083  * This routine replays a modification made to a buffer at runtime.
2084  * There are actually two types of buffer, regular and inode, which
2085  * are handled differently.  Inode buffers are handled differently
2086  * in that we only recover a specific set of data from them, namely
2087  * the inode di_next_unlinked fields.  This is because all other inode
2088  * data is actually logged via inode records and any data we replay
2089  * here which overlaps that may be stale.
2090  *
2091  * When meta-data buffers are freed at run time we log a buffer item
2092  * with the XFS_BLF_CANCEL bit set to indicate that previous copies
2093  * of the buffer in the log should not be replayed at recovery time.
2094  * This is so that if the blocks covered by the buffer are reused for
2095  * file data before we crash we don't end up replaying old, freed
2096  * meta-data into a user's file.
2097  *
2098  * To handle the cancellation of buffer log items, we make two passes
2099  * over the log during recovery.  During the first we build a table of
2100  * those buffers which have been cancelled, and during the second we
2101  * only replay those buffers which do not have corresponding cancel
2102  * records in the table.  See xlog_recover_do_buffer_pass[1,2] above
2103  * for more details on the implementation of the table of cancel records.
2104  */
2105 STATIC int
2106 xlog_recover_buffer_pass2(
2107         xlog_t                  *log,
2108         xlog_recover_item_t     *item)
2109 {
2110         xfs_buf_log_format_t    *buf_f = item->ri_buf[0].i_addr;
2111         xfs_mount_t             *mp = log->l_mp;
2112         xfs_buf_t               *bp;
2113         int                     error;
2114         uint                    buf_flags;
2115 
2116         /*
2117          * In this pass we only want to recover all the buffers which have
2118          * not been cancelled and are not cancellation buffers themselves.
2119          */
2120         if (xlog_check_buffer_cancelled(log, buf_f->blf_blkno,
2121                         buf_f->blf_len, buf_f->blf_flags)) {
2122                 trace_xfs_log_recover_buf_cancel(log, buf_f);
2123                 return 0;
2124         }
2125 
2126         trace_xfs_log_recover_buf_recover(log, buf_f);
2127 
2128         buf_flags = XBF_LOCK;
2129         if (!(buf_f->blf_flags & XFS_BLF_INODE_BUF))
2130                 buf_flags |= XBF_MAPPED;
2131 
2132         bp = xfs_buf_read(mp->m_ddev_targp, buf_f->blf_blkno, buf_f->blf_len,
2133                           buf_flags);
2134         if (!bp)
2135                 return XFS_ERROR(ENOMEM);
2136         error = bp->b_error;
2137         if (error) {
2138                 xfs_ioerror_alert("xlog_recover_do..(read#1)", mp,
2139                                   bp, buf_f->blf_blkno);
2140                 xfs_buf_relse(bp);
2141                 return error;
2142         }
2143 
2144         if (buf_f->blf_flags & XFS_BLF_INODE_BUF) {
2145                 error = xlog_recover_do_inode_buffer(mp, item, bp, buf_f);
2146         } else if (buf_f->blf_flags &
2147                   (XFS_BLF_UDQUOT_BUF|XFS_BLF_PDQUOT_BUF|XFS_BLF_GDQUOT_BUF)) {
2148                 xlog_recover_do_dquot_buffer(mp, log, item, bp, buf_f);
2149         } else {
2150                 xlog_recover_do_reg_buffer(mp, item, bp, buf_f);
2151         }
2152         if (error)
2153                 return XFS_ERROR(error);
2154 
2155         /*
2156          * Perform delayed write on the buffer.  Asynchronous writes will be
2157          * slower when taking into account all the buffers to be flushed.
2158          *
2159          * Also make sure that only inode buffers with good sizes stay in
2160          * the buffer cache.  The kernel moves inodes in buffers of 1 block
2161          * or XFS_INODE_CLUSTER_SIZE bytes, whichever is bigger.  The inode
2162          * buffers in the log can be a different size if the log was generated
2163          * by an older kernel using unclustered inode buffers or a newer kernel
2164          * running with a different inode cluster size.  Regardless, if the
2165          * the inode buffer size isn't MAX(blocksize, XFS_INODE_CLUSTER_SIZE)
2166          * for *our* value of XFS_INODE_CLUSTER_SIZE, then we need to keep
2167          * the buffer out of the buffer cache so that the buffer won't
2168          * overlap with future reads of those inodes.
2169          */
2170         if (XFS_DINODE_MAGIC ==
2171             be16_to_cpu(*((__be16 *)xfs_buf_offset(bp, 0))) &&
2172             (XFS_BUF_COUNT(bp) != MAX(log->l_mp->m_sb.sb_blocksize,
2173                         (__uint32_t)XFS_INODE_CLUSTER_SIZE(log->l_mp)))) {
2174                 XFS_BUF_STALE(bp);
2175                 error = xfs_bwrite(mp, bp);
2176         } else {
2177                 ASSERT(bp->b_target->bt_mount == mp);
2178                 bp->b_iodone = xlog_recover_iodone;
2179                 xfs_bdwrite(mp, bp);
2180         }
2181 
2182         return (error);
2183 }
2184 
2185 STATIC int
2186 xlog_recover_inode_pass2(
2187         xlog_t                  *log,
2188         xlog_recover_item_t     *item)
2189 {
2190         xfs_inode_log_format_t  *in_f;
2191         xfs_mount_t             *mp = log->l_mp;
2192         xfs_buf_t               *bp;
2193         xfs_dinode_t            *dip;
2194         int                     len;
2195         xfs_caddr_t             src;
2196         xfs_caddr_t             dest;
2197         int                     error;
2198         int                     attr_index;
2199         uint                    fields;
2200         xfs_icdinode_t          *dicp;
2201         int                     need_free = 0;
2202 
2203         if (item->ri_buf[0].i_len == sizeof(xfs_inode_log_format_t)) {
2204                 in_f = item->ri_buf[0].i_addr;
2205         } else {
2206                 in_f = kmem_alloc(sizeof(xfs_inode_log_format_t), KM_SLEEP);
2207                 need_free = 1;
2208                 error = xfs_inode_item_format_convert(&item->ri_buf[0], in_f);
2209                 if (error)
2210                         goto error;
2211         }
2212 
2213         /*
2214          * Inode buffers can be freed, look out for it,
2215          * and do not replay the inode.
2216          */
2217         if (xlog_check_buffer_cancelled(log, in_f->ilf_blkno,
2218                                         in_f->ilf_len, 0)) {
2219                 error = 0;
2220                 trace_xfs_log_recover_inode_cancel(log, in_f);
2221                 goto error;
2222         }
2223         trace_xfs_log_recover_inode_recover(log, in_f);
2224 
2225         bp = xfs_buf_read(mp->m_ddev_targp, in_f->ilf_blkno, in_f->ilf_len,
2226                           XBF_LOCK);
2227         if (!bp) {
2228                 error = ENOMEM;
2229                 goto error;
2230         }
2231         error = bp->b_error;
2232         if (error) {
2233                 xfs_ioerror_alert("xlog_recover_do..(read#2)", mp,
2234                                   bp, in_f->ilf_blkno);
2235                 xfs_buf_relse(bp);
2236                 goto error;
2237         }
2238         ASSERT(in_f->ilf_fields & XFS_ILOG_CORE);
2239         dip = (xfs_dinode_t *)xfs_buf_offset(bp, in_f->ilf_boffset);
2240 
2241         /*
2242          * Make sure the place we're flushing out to really looks
2243          * like an inode!
2244          */
2245         if (unlikely(dip->di_magic != cpu_to_be16(XFS_DINODE_MAGIC))) {
2246                 xfs_buf_relse(bp);
2247                 xfs_alert(mp,
2248         "%s: Bad inode magic number, dip = 0x%p, dino bp = 0x%p, ino = %Ld",
2249                         __func__, dip, bp, in_f->ilf_ino);
2250                 XFS_ERROR_REPORT("xlog_recover_inode_pass2(1)",
2251                                  XFS_ERRLEVEL_LOW, mp);
2252                 error = EFSCORRUPTED;
2253                 goto error;
2254         }
2255         dicp = item->ri_buf[1].i_addr;
2256         if (unlikely(dicp->di_magic != XFS_DINODE_MAGIC)) {
2257                 xfs_buf_relse(bp);
2258                 xfs_alert(mp,
2259                         "%s: Bad inode log record, rec ptr 0x%p, ino %Ld",
2260                         __func__, item, in_f->ilf_ino);
2261                 XFS_ERROR_REPORT("xlog_recover_inode_pass2(2)",
2262                                  XFS_ERRLEVEL_LOW, mp);
2263                 error = EFSCORRUPTED;
2264                 goto error;
2265         }
2266 
2267         /* Skip replay when the on disk inode is newer than the log one */
2268         if (dicp->di_flushiter < be16_to_cpu(dip->di_flushiter)) {
2269                 /*
2270                  * Deal with the wrap case, DI_MAX_FLUSH is less
2271                  * than smaller numbers
2272                  */
2273                 if (be16_to_cpu(dip->di_flushiter) == DI_MAX_FLUSH &&
2274                     dicp->di_flushiter < (DI_MAX_FLUSH >> 1)) {
2275                         /* do nothing */
2276                 } else {
2277                         xfs_buf_relse(bp);
2278                         trace_xfs_log_recover_inode_skip(log, in_f);
2279                         error = 0;
2280                         goto error;
2281                 }
2282         }
2283         /* Take the opportunity to reset the flush iteration count */
2284         dicp->di_flushiter = 0;
2285 
2286         if (unlikely(S_ISREG(dicp->di_mode))) {
2287                 if ((dicp->di_format != XFS_DINODE_FMT_EXTENTS) &&
2288                     (dicp->di_format != XFS_DINODE_FMT_BTREE)) {
2289                         XFS_CORRUPTION_ERROR("xlog_recover_inode_pass2(3)",
2290                                          XFS_ERRLEVEL_LOW, mp, dicp);
2291                         xfs_buf_relse(bp);
2292                         xfs_alert(mp,
2293                 "%s: Bad regular inode log record, rec ptr 0x%p, "
2294                 "ino ptr = 0x%p, ino bp = 0x%p, ino %Ld",
2295                                 __func__, item, dip, bp, in_f->ilf_ino);
2296                         error = EFSCORRUPTED;
2297                         goto error;
2298                 }
2299         } else if (unlikely(S_ISDIR(dicp->di_mode))) {
2300                 if ((dicp->di_format != XFS_DINODE_FMT_EXTENTS) &&
2301                     (dicp->di_format != XFS_DINODE_FMT_BTREE) &&
2302                     (dicp->di_format != XFS_DINODE_FMT_LOCAL)) {
2303                         XFS_CORRUPTION_ERROR("xlog_recover_inode_pass2(4)",
2304                                              XFS_ERRLEVEL_LOW, mp, dicp);
2305                         xfs_buf_relse(bp);
2306                         xfs_alert(mp,
2307                 "%s: Bad dir inode log record, rec ptr 0x%p, "
2308                 "ino ptr = 0x%p, ino bp = 0x%p, ino %Ld",
2309                                 __func__, item, dip, bp, in_f->ilf_ino);
2310                         error = EFSCORRUPTED;
2311                         goto error;
2312                 }
2313         }
2314         if (unlikely(dicp->di_nextents + dicp->di_anextents > dicp->di_nblocks)){
2315                 XFS_CORRUPTION_ERROR("xlog_recover_inode_pass2(5)",
2316                                      XFS_ERRLEVEL_LOW, mp, dicp);
2317                 xfs_buf_relse(bp);
2318                 xfs_alert(mp,
2319         "%s: Bad inode log record, rec ptr 0x%p, dino ptr 0x%p, "
2320         "dino bp 0x%p, ino %Ld, total extents = %d, nblocks = %Ld",
2321                         __func__, item, dip, bp, in_f->ilf_ino,
2322                         dicp->di_nextents + dicp->di_anextents,
2323                         dicp->di_nblocks);
2324                 error = EFSCORRUPTED;
2325                 goto error;
2326         }
2327         if (unlikely(dicp->di_forkoff > mp->m_sb.sb_inodesize)) {
2328                 XFS_CORRUPTION_ERROR("xlog_recover_inode_pass2(6)",
2329                                      XFS_ERRLEVEL_LOW, mp, dicp);
2330                 xfs_buf_relse(bp);
2331                 xfs_alert(mp,
2332         "%s: Bad inode log record, rec ptr 0x%p, dino ptr 0x%p, "
2333         "dino bp 0x%p, ino %Ld, forkoff 0x%x", __func__,
2334                         item, dip, bp, in_f->ilf_ino, dicp->di_forkoff);
2335                 error = EFSCORRUPTED;
2336                 goto error;
2337         }
2338         if (unlikely(item->ri_buf[1].i_len > sizeof(struct xfs_icdinode))) {
2339                 XFS_CORRUPTION_ERROR("xlog_recover_inode_pass2(7)",
2340                                      XFS_ERRLEVEL_LOW, mp, dicp);
2341                 xfs_buf_relse(bp);
2342                 xfs_alert(mp,
2343                         "%s: Bad inode log record length %d, rec ptr 0x%p",
2344                         __func__, item->ri_buf[1].i_len, item);
2345                 error = EFSCORRUPTED;
2346                 goto error;
2347         }
2348 
2349         /* The core is in in-core format */
2350         xfs_dinode_to_disk(dip, item->ri_buf[1].i_addr);
2351 
2352         /* the rest is in on-disk format */
2353         if (item->ri_buf[1].i_len > sizeof(struct xfs_icdinode)) {
2354                 memcpy((xfs_caddr_t) dip + sizeof(struct xfs_icdinode),
2355                         item->ri_buf[1].i_addr + sizeof(struct xfs_icdinode),
2356                         item->ri_buf[1].i_len  - sizeof(struct xfs_icdinode));
2357         }
2358 
2359         fields = in_f->ilf_fields;
2360         switch (fields & (XFS_ILOG_DEV | XFS_ILOG_UUID)) {
2361         case XFS_ILOG_DEV:
2362                 xfs_dinode_put_rdev(dip, in_f->ilf_u.ilfu_rdev);
2363                 break;
2364         case XFS_ILOG_UUID:
2365                 memcpy(XFS_DFORK_DPTR(dip),
2366                        &in_f->ilf_u.ilfu_uuid,
2367                        sizeof(uuid_t));
2368                 break;
2369         }
2370 
2371         if (in_f->ilf_size == 2)
2372                 goto write_inode_buffer;
2373         len = item->ri_buf[2].i_len;
2374         src = item->ri_buf[2].i_addr;
2375         ASSERT(in_f->ilf_size <= 4);
2376         ASSERT((in_f->ilf_size == 3) || (fields & XFS_ILOG_AFORK));
2377         ASSERT(!(fields & XFS_ILOG_DFORK) ||
2378                (len == in_f->ilf_dsize));
2379 
2380         switch (fields & XFS_ILOG_DFORK) {
2381         case XFS_ILOG_DDATA:
2382         case XFS_ILOG_DEXT:
2383                 memcpy(XFS_DFORK_DPTR(dip), src, len);
2384                 break;
2385 
2386         case XFS_ILOG_DBROOT:
2387                 xfs_bmbt_to_bmdr(mp, (struct xfs_btree_block *)src, len,
2388                                  (xfs_bmdr_block_t *)XFS_DFORK_DPTR(dip),
2389                                  XFS_DFORK_DSIZE(dip, mp));
2390                 break;
2391 
2392         default:
2393                 /*
2394                  * There are no data fork flags set.
2395                  */
2396                 ASSERT((fields & XFS_ILOG_DFORK) == 0);
2397                 break;
2398         }
2399 
2400         /*
2401          * If we logged any attribute data, recover it.  There may or
2402          * may not have been any other non-core data logged in this
2403          * transaction.
2404          */
2405         if (in_f->ilf_fields & XFS_ILOG_AFORK) {
2406                 if (in_f->ilf_fields & XFS_ILOG_DFORK) {
2407                         attr_index = 3;
2408                 } else {
2409                         attr_index = 2;
2410                 }
2411                 len = item->ri_buf[attr_index].i_len;
2412                 src = item->ri_buf[attr_index].i_addr;
2413                 ASSERT(len == in_f->ilf_asize);
2414 
2415                 switch (in_f->ilf_fields & XFS_ILOG_AFORK) {
2416                 case XFS_ILOG_ADATA:
2417                 case XFS_ILOG_AEXT:
2418                         dest = XFS_DFORK_APTR(dip);
2419                         ASSERT(len <= XFS_DFORK_ASIZE(dip, mp));
2420                         memcpy(dest, src, len);
2421                         break;
2422 
2423                 case XFS_ILOG_ABROOT:
2424                         dest = XFS_DFORK_APTR(dip);
2425                         xfs_bmbt_to_bmdr(mp, (struct xfs_btree_block *)src,
2426                                          len, (xfs_bmdr_block_t*)dest,
2427                                          XFS_DFORK_ASIZE(dip, mp));
2428                         break;
2429 
2430                 default:
2431                         xfs_warn(log->l_mp, "%s: Invalid flag", __func__);
2432                         ASSERT(0);
2433                         xfs_buf_relse(bp);
2434                         error = EIO;
2435                         goto error;
2436                 }
2437         }
2438 
2439 write_inode_buffer:
2440         ASSERT(bp->b_target->bt_mount == mp);
2441         bp->b_iodone = xlog_recover_iodone;
2442         xfs_bdwrite(mp, bp);
2443 error:
2444         if (need_free)
2445                 kmem_free(in_f);
2446         return XFS_ERROR(error);
2447 }
2448 
2449 /*
2450  * Recover QUOTAOFF records. We simply make a note of it in the xlog_t
2451  * structure, so that we know not to do any dquot item or dquot buffer recovery,
2452  * of that type.
2453  */
2454 STATIC int
2455 xlog_recover_quotaoff_pass1(
2456         xlog_t                  *log,
2457         xlog_recover_item_t     *item)
2458 {
2459         xfs_qoff_logformat_t    *qoff_f = item->ri_buf[0].i_addr;
2460         ASSERT(qoff_f);
2461 
2462         /*
2463          * The logitem format's flag tells us if this was user quotaoff,
2464          * group/project quotaoff or both.
2465          */
2466         if (qoff_f->qf_flags & XFS_UQUOTA_ACCT)
2467                 log->l_quotaoffs_flag |= XFS_DQ_USER;
2468         if (qoff_f->qf_flags & XFS_PQUOTA_ACCT)
2469                 log->l_quotaoffs_flag |= XFS_DQ_PROJ;
2470         if (qoff_f->qf_flags & XFS_GQUOTA_ACCT)
2471                 log->l_quotaoffs_flag |= XFS_DQ_GROUP;
2472 
2473         return (0);
2474 }
2475 
2476 /*
2477  * Recover a dquot record
2478  */
2479 STATIC int
2480 xlog_recover_dquot_pass2(
2481         xlog_t                  *log,
2482         xlog_recover_item_t     *item)
2483 {
2484         xfs_mount_t             *mp = log->l_mp;
2485         xfs_buf_t               *bp;
2486         struct xfs_disk_dquot   *ddq, *recddq;
2487         int                     error;
2488         xfs_dq_logformat_t      *dq_f;
2489         uint                    type;
2490 
2491 
2492         /*
2493          * Filesystems are required to send in quota flags at mount time.
2494          */
2495         if (mp->m_qflags == 0)
2496                 return (0);
2497 
2498         recddq = item->ri_buf[1].i_addr;
2499         if (recddq == NULL) {
2500                 xfs_alert(log->l_mp, "NULL dquot in %s.", __func__);
2501                 return XFS_ERROR(EIO);
2502         }
2503         if (item->ri_buf[1].i_len < sizeof(xfs_disk_dquot_t)) {
2504                 xfs_alert(log->l_mp, "dquot too small (%d) in %s.",
2505                         item->ri_buf[1].i_len, __func__);
2506                 return XFS_ERROR(EIO);
2507         }
2508 
2509         /*
2510          * This type of quotas was turned off, so ignore this record.
2511          */
2512         type = recddq->d_flags & (XFS_DQ_USER | XFS_DQ_PROJ | XFS_DQ_GROUP);
2513         ASSERT(type);
2514         if (log->l_quotaoffs_flag & type)
2515                 return (0);
2516 
2517         /*
2518          * At this point we know that quota was _not_ turned off.
2519          * Since the mount flags are not indicating to us otherwise, this
2520          * must mean that quota is on, and the dquot needs to be replayed.
2521          * Remember that we may not have fully recovered the superblock yet,
2522          * so we can't do the usual trick of looking at the SB quota bits.
2523          *
2524          * The other possibility, of course, is that the quota subsystem was
2525          * removed since the last mount - ENOSYS.
2526          */
2527         dq_f = item->ri_buf[0].i_addr;
2528         ASSERT(dq_f);
2529         error = xfs_qm_dqcheck(mp, recddq, dq_f->qlf_id, 0, XFS_QMOPT_DOWARN,
2530                            "xlog_recover_dquot_pass2 (log copy)");
2531         if (error)
2532                 return XFS_ERROR(EIO);
2533         ASSERT(dq_f->qlf_len == 1);
2534 
2535         error = xfs_read_buf(mp, mp->m_ddev_targp,
2536                              dq_f->qlf_blkno,
2537                              XFS_FSB_TO_BB(mp, dq_f->qlf_len),
2538                              0, &bp);
2539         if (error) {
2540                 xfs_ioerror_alert("xlog_recover_do..(read#3)", mp,
2541                                   bp, dq_f->qlf_blkno);
2542                 return error;
2543         }
2544         ASSERT(bp);
2545         ddq = (xfs_disk_dquot_t *)xfs_buf_offset(bp, dq_f->qlf_boffset);
2546 
2547         /*
2548          * At least the magic num portion should be on disk because this
2549          * was among a chunk of dquots created earlier, and we did some
2550          * minimal initialization then.
2551          */
2552         error = xfs_qm_dqcheck(mp, ddq, dq_f->qlf_id, 0, XFS_QMOPT_DOWARN,
2553                            "xlog_recover_dquot_pass2");
2554         if (error) {
2555                 xfs_buf_relse(bp);
2556                 return XFS_ERROR(EIO);
2557         }
2558 
2559         memcpy(ddq, recddq, item->ri_buf[1].i_len);
2560 
2561         ASSERT(dq_f->qlf_size == 2);
2562         ASSERT(bp->b_target->bt_mount == mp);
2563         bp->b_iodone = xlog_recover_iodone;
2564         xfs_bdwrite(mp, bp);
2565 
2566         return (0);
2567 }
2568 
2569 /*
2570  * This routine is called to create an in-core extent free intent
2571  * item from the efi format structure which was logged on disk.
2572  * It allocates an in-core efi, copies the extents from the format
2573  * structure into it, and adds the efi to the AIL with the given
2574  * LSN.
2575  */
2576 STATIC int
2577 xlog_recover_efi_pass2(
2578         xlog_t                  *log,
2579         xlog_recover_item_t     *item,
2580         xfs_lsn_t               lsn)
2581 {
2582         int                     error;
2583         xfs_mount_t             *mp = log->l_mp;
2584         xfs_efi_log_item_t      *efip;
2585         xfs_efi_log_format_t    *efi_formatp;
2586 
2587         efi_formatp = item->ri_buf[0].i_addr;
2588 
2589         efip = xfs_efi_init(mp, efi_formatp->efi_nextents);
2590         if ((error = xfs_efi_copy_format(&(item->ri_buf[0]),
2591                                          &(efip->efi_format)))) {
2592                 xfs_efi_item_free(efip);
2593                 return error;
2594         }
2595         atomic_set(&efip->efi_next_extent, efi_formatp->efi_nextents);
2596 
2597         spin_lock(&log->l_ailp->xa_lock);
2598         /*
2599          * xfs_trans_ail_update() drops the AIL lock.
2600          */
2601         xfs_trans_ail_update(log->l_ailp, &efip->efi_item, lsn);
2602         return 0;
2603 }
2604 
2605 
2606 /*
2607  * This routine is called when an efd format structure is found in
2608  * a committed transaction in the log.  It's purpose is to cancel
2609  * the corresponding efi if it was still in the log.  To do this
2610  * it searches the AIL for the efi with an id equal to that in the
2611  * efd format structure.  If we find it, we remove the efi from the
2612  * AIL and free it.
2613  */
2614 STATIC int
2615 xlog_recover_efd_pass2(
2616         xlog_t                  *log,
2617         xlog_recover_item_t     *item)
2618 {
2619         xfs_efd_log_format_t    *efd_formatp;
2620         xfs_efi_log_item_t      *efip = NULL;
2621         xfs_log_item_t          *lip;
2622         __uint64_t              efi_id;
2623         struct xfs_ail_cursor   cur;
2624         struct xfs_ail          *ailp = log->l_ailp;
2625 
2626         efd_formatp = item->ri_buf[0].i_addr;
2627         ASSERT((item->ri_buf[0].i_len == (sizeof(xfs_efd_log_format_32_t) +
2628                 ((efd_formatp->efd_nextents - 1) * sizeof(xfs_extent_32_t)))) ||
2629                (item->ri_buf[0].i_len == (sizeof(xfs_efd_log_format_64_t) +
2630                 ((efd_formatp->efd_nextents - 1) * sizeof(xfs_extent_64_t)))));
2631         efi_id = efd_formatp->efd_efi_id;
2632 
2633         /*
2634          * Search for the efi with the id in the efd format structure
2635          * in the AIL.
2636          */
2637         spin_lock(&ailp->xa_lock);
2638         lip = xfs_trans_ail_cursor_first(ailp, &cur, 0);
2639         while (lip != NULL) {
2640                 if (lip->li_type == XFS_LI_EFI) {
2641                         efip = (xfs_efi_log_item_t *)lip;
2642                         if (efip->efi_format.efi_id == efi_id) {
2643                                 /*
2644                                  * xfs_trans_ail_delete() drops the
2645                                  * AIL lock.
2646                                  */
2647                                 xfs_trans_ail_delete(ailp, lip);
2648                                 xfs_efi_item_free(efip);
2649                                 spin_lock(&ailp->xa_lock);
2650                                 break;
2651                         }
2652                 }
2653                 lip = xfs_trans_ail_cursor_next(ailp, &cur);
2654         }
2655         xfs_trans_ail_cursor_done(ailp, &cur);
2656         spin_unlock(&ailp->xa_lock);
2657 
2658         return 0;
2659 }
2660 
2661 /*
2662  * Free up any resources allocated by the transaction
2663  *
2664  * Remember that EFIs, EFDs, and IUNLINKs are handled later.
2665  */
2666 STATIC void
2667 xlog_recover_free_trans(
2668         struct xlog_recover     *trans)
2669 {
2670         xlog_recover_item_t     *item, *n;
2671         int                     i;
2672 
2673         list_for_each_entry_safe(item, n, &trans->r_itemq, ri_list) {
2674                 /* Free the regions in the item. */
2675                 list_del(&item->ri_list);
2676                 for (i = 0; i < item->ri_cnt; i++)
2677                         kmem_free(item->ri_buf[i].i_addr);
2678                 /* Free the item itself */
2679                 kmem_free(item->ri_buf);
2680                 kmem_free(item);
2681         }
2682         /* Free the transaction recover structure */
2683         kmem_free(trans);
2684 }
2685 
2686 STATIC int
2687 xlog_recover_commit_pass1(
2688         struct log              *log,
2689         struct xlog_recover     *trans,
2690         xlog_recover_item_t     *item)
2691 {
2692         trace_xfs_log_recover_item_recover(log, trans, item, XLOG_RECOVER_PASS1);
2693 
2694         switch (ITEM_TYPE(item)) {
2695         case XFS_LI_BUF:
2696                 return xlog_recover_buffer_pass1(log, item);
2697         case XFS_LI_QUOTAOFF:
2698                 return xlog_recover_quotaoff_pass1(log, item);
2699         case XFS_LI_INODE:
2700         case XFS_LI_EFI:
2701         case XFS_LI_EFD:
2702         case XFS_LI_DQUOT:
2703                 /* nothing to do in pass 1 */
2704                 return 0;
2705         default:
2706                 xfs_warn(log->l_mp, "%s: invalid item type (%d)",
2707                         __func__, ITEM_TYPE(item));
2708                 ASSERT(0);
2709                 return XFS_ERROR(EIO);
2710         }
2711 }
2712 
2713 STATIC int
2714 xlog_recover_commit_pass2(
2715         struct log              *log,
2716         struct xlog_recover     *trans,
2717         xlog_recover_item_t     *item)
2718 {
2719         trace_xfs_log_recover_item_recover(log, trans, item, XLOG_RECOVER_PASS2);
2720 
2721         switch (ITEM_TYPE(item)) {
2722         case XFS_LI_BUF:
2723                 return xlog_recover_buffer_pass2(log, item);
2724         case XFS_LI_INODE:
2725                 return xlog_recover_inode_pass2(log, item);
2726         case XFS_LI_EFI:
2727                 return xlog_recover_efi_pass2(log, item, trans->r_lsn);
2728         case XFS_LI_EFD:
2729                 return xlog_recover_efd_pass2(log, item);
2730         case XFS_LI_DQUOT:
2731                 return xlog_recover_dquot_pass2(log, item);
2732         case XFS_LI_QUOTAOFF:
2733                 /* nothing to do in pass2 */
2734                 return 0;
2735         default:
2736                 xfs_warn(log->l_mp, "%s: invalid item type (%d)",
2737                         __func__, ITEM_TYPE(item));
2738                 ASSERT(0);
2739                 return XFS_ERROR(EIO);
2740         }
2741 }
2742 
2743 /*
2744  * Perform the transaction.
2745  *
2746  * If the transaction modifies a buffer or inode, do it now.  Otherwise,
2747  * EFIs and EFDs get queued up by adding entries into the AIL for them.
2748  */
2749 STATIC int
2750 xlog_recover_commit_trans(
2751         struct log              *log,
2752         struct xlog_recover     *trans,
2753         int                     pass)
2754 {
2755         int                     error = 0;
2756         xlog_recover_item_t     *item;
2757 
2758         hlist_del(&trans->r_list);
2759 
2760         error = xlog_recover_reorder_trans(log, trans, pass);
2761         if (error)
2762                 return error;
2763 
2764         list_for_each_entry(item, &trans->r_itemq, ri_list) {
2765                 if (pass == XLOG_RECOVER_PASS1)
2766                         error = xlog_recover_commit_pass1(log, trans, item);
2767                 else
2768                         error = xlog_recover_commit_pass2(log, trans, item);
2769                 if (error)
2770                         return error;
2771         }
2772 
2773         xlog_recover_free_trans(trans);
2774         return 0;
2775 }
2776 
2777 STATIC int
2778 xlog_recover_unmount_trans(
2779         struct log              *log,
2780         xlog_recover_t          *trans)
2781 {
2782         /* Do nothing now */
2783         xfs_warn(log->l_mp, "%s: Unmount LR", __func__);
2784         return 0;
2785 }
2786 
2787 /*
2788  * There are two valid states of the r_state field.  0 indicates that the
2789  * transaction structure is in a normal state.  We have either seen the
2790  * start of the transaction or the last operation we added was not a partial
2791  * operation.  If the last operation we added to the transaction was a
2792  * partial operation, we need to mark r_state with XLOG_WAS_CONT_TRANS.
2793  *
2794  * NOTE: skip LRs with 0 data length.
2795  */
2796 STATIC int
2797 xlog_recover_process_data(
2798         xlog_t                  *log,
2799         struct hlist_head       rhash[],
2800         xlog_rec_header_t       *rhead,
2801         xfs_caddr_t             dp,
2802         int                     pass)
2803 {
2804         xfs_caddr_t             lp;
2805         int                     num_logops;
2806         xlog_op_header_t        *ohead;
2807         xlog_recover_t          *trans;
2808         xlog_tid_t              tid;
2809         int                     error;
2810         unsigned long           hash;
2811         uint                    flags;
2812 
2813         lp = dp + be32_to_cpu(rhead->h_len);
2814         num_logops = be32_to_cpu(rhead->h_num_logops);
2815 
2816         /* check the log format matches our own - else we can't recover */
2817         if (xlog_header_check_recover(log->l_mp, rhead))
2818                 return (XFS_ERROR(EIO));
2819 
2820         while ((dp < lp) && num_logops) {
2821                 ASSERT(dp + sizeof(xlog_op_header_t) <= lp);
2822                 ohead = (xlog_op_header_t *)dp;
2823                 dp += sizeof(xlog_op_header_t);
2824                 if (ohead->oh_clientid != XFS_TRANSACTION &&
2825                     ohead->oh_clientid != XFS_LOG) {
2826                         xfs_warn(log->l_mp, "%s: bad clientid 0x%x",
2827                                         __func__, ohead->oh_clientid);
2828                         ASSERT(0);
2829                         return (XFS_ERROR(EIO));
2830                 }
2831                 tid = be32_to_cpu(ohead->oh_tid);
2832                 hash = XLOG_RHASH(tid);
2833                 trans = xlog_recover_find_tid(&rhash[hash], tid);
2834                 if (trans == NULL) {               /* not found; add new tid */
2835                         if (ohead->oh_flags & XLOG_START_TRANS)
2836                                 xlog_recover_new_tid(&rhash[hash], tid,
2837                                         be64_to_cpu(rhead->h_lsn));
2838                 } else {
2839                         if (dp + be32_to_cpu(ohead->oh_len) > lp) {
2840                                 xfs_warn(log->l_mp, "%s: bad length 0x%x",
2841                                         __func__, be32_to_cpu(ohead->oh_len));
2842                                 WARN_ON(1);
2843                                 return (XFS_ERROR(EIO));
2844                         }
2845                         flags = ohead->oh_flags & ~XLOG_END_TRANS;
2846                         if (flags & XLOG_WAS_CONT_TRANS)
2847                                 flags &= ~XLOG_CONTINUE_TRANS;
2848                         switch (flags) {
2849                         case XLOG_COMMIT_TRANS:
2850                                 error = xlog_recover_commit_trans(log,
2851                                                                 trans, pass);
2852                                 break;
2853                         case XLOG_UNMOUNT_TRANS:
2854                                 error = xlog_recover_unmount_trans(log, trans);
2855                                 break;
2856                         case XLOG_WAS_CONT_TRANS:
2857                                 error = xlog_recover_add_to_cont_trans(log,
2858                                                 trans, dp,
2859                                                 be32_to_cpu(ohead->oh_len));
2860                                 break;
2861                         case XLOG_START_TRANS:
2862                                 xfs_warn(log->l_mp, "%s: bad transaction",
2863                                         __func__);
2864                                 ASSERT(0);
2865                                 error = XFS_ERROR(EIO);
2866                                 break;
2867                         case 0:
2868                         case XLOG_CONTINUE_TRANS:
2869                                 error = xlog_recover_add_to_trans(log, trans,
2870                                                 dp, be32_to_cpu(ohead->oh_len));
2871                                 break;
2872                         default:
2873                                 xfs_warn(log->l_mp, "%s: bad flag 0x%x",
2874                                         __func__, flags);
2875                                 ASSERT(0);
2876                                 error = XFS_ERROR(EIO);
2877                                 break;
2878                         }
2879                         if (error)
2880                                 return error;
2881                 }
2882                 dp += be32_to_cpu(ohead->oh_len);
2883                 num_logops--;
2884         }
2885         return 0;
2886 }
2887 
2888 /*
2889  * Process an extent free intent item that was recovered from
2890  * the log.  We need to free the extents that it describes.
2891  */
2892 STATIC int
2893 xlog_recover_process_efi(
2894         xfs_mount_t             *mp,
2895         xfs_efi_log_item_t      *efip)
2896 {
2897         xfs_efd_log_item_t      *efdp;
2898         xfs_trans_t             *tp;
2899         int                     i;
2900         int                     error = 0;
2901         xfs_extent_t            *extp;
2902         xfs_fsblock_t           startblock_fsb;
2903 
2904         ASSERT(!test_bit(XFS_EFI_RECOVERED, &efip->efi_flags));
2905 
2906         /*
2907          * First check the validity of the extents described by the
2908          * EFI.  If any are bad, then assume that all are bad and
2909          * just toss the EFI.
2910          */
2911         for (i = 0; i < efip->efi_format.efi_nextents; i++) {
2912                 extp = &(efip->efi_format.efi_extents[i]);
2913                 startblock_fsb = XFS_BB_TO_FSB(mp,
2914                                    XFS_FSB_TO_DADDR(mp, extp->ext_start));
2915                 if ((startblock_fsb == 0) ||
2916                     (extp->ext_len == 0) ||
2917                     (startblock_fsb >= mp->m_sb.sb_dblocks) ||
2918                     (extp->ext_len >= mp->m_sb.sb_agblocks)) {
2919                         /*
2920                          * This will pull the EFI from the AIL and
2921                          * free the memory associated with it.
2922                          */
2923                         xfs_efi_release(efip, efip->efi_format.efi_nextents);
2924                         return XFS_ERROR(EIO);
2925                 }
2926         }
2927 
2928         tp = xfs_trans_alloc(mp, 0);
2929         error = xfs_trans_reserve(tp, 0, XFS_ITRUNCATE_LOG_RES(mp), 0, 0, 0);
2930         if (error)
2931                 goto abort_error;
2932         efdp = xfs_trans_get_efd(tp, efip, efip->efi_format.efi_nextents);
2933 
2934         for (i = 0; i < efip->efi_format.efi_nextents; i++) {
2935                 extp = &(efip->efi_format.efi_extents[i]);
2936                 error = xfs_free_extent(tp, extp->ext_start, extp->ext_len);
2937                 if (error)
2938                         goto abort_error;
2939                 xfs_trans_log_efd_extent(tp, efdp, extp->ext_start,
2940                                          extp->ext_len);
2941         }
2942 
2943         set_bit(XFS_EFI_RECOVERED, &efip->efi_flags);
2944         error = xfs_trans_commit(tp, 0);
2945         return error;
2946 
2947 abort_error:
2948         xfs_trans_cancel(tp, XFS_TRANS_ABORT);
2949         return error;
2950 }
2951 
2952 /*
2953  * When this is called, all of the EFIs which did not have
2954  * corresponding EFDs should be in the AIL.  What we do now
2955  * is free the extents associated with each one.
2956  *
2957  * Since we process the EFIs in normal transactions, they
2958  * will be removed at some point after the commit.  This prevents
2959  * us from just walking down the list processing each one.
2960  * We'll use a flag in the EFI to skip those that we've already
2961  * processed and use the AIL iteration mechanism's generation
2962  * count to try to speed this up at least a bit.
2963  *
2964  * When we start, we know that the EFIs are the only things in
2965  * the AIL.  As we process them, however, other items are added
2966  * to the AIL.  Since everything added to the AIL must come after
2967  * everything already in the AIL, we stop processing as soon as
2968  * we see something other than an EFI in the AIL.
2969  */
2970 STATIC int
2971 xlog_recover_process_efis(
2972         xlog_t                  *log)
2973 {
2974         xfs_log_item_t          *lip;
2975         xfs_efi_log_item_t      *efip;
2976         int                     error = 0;
2977         struct xfs_ail_cursor   cur;
2978         struct xfs_ail          *ailp;
2979 
2980         ailp = log->l_ailp;
2981         spin_lock(&ailp->xa_lock);
2982         lip = xfs_trans_ail_cursor_first(ailp, &cur, 0);
2983         while (lip != NULL) {
2984                 /*
2985                  * We're done when we see something other than an EFI.
2986                  * There should be no EFIs left in the AIL now.
2987                  */
2988                 if (lip->li_type != XFS_LI_EFI) {
2989 #ifdef DEBUG
2990                         for (; lip; lip = xfs_trans_ail_cursor_next(ailp, &cur))
2991                                 ASSERT(lip->li_type != XFS_LI_EFI);
2992 #endif
2993                         break;
2994                 }
2995 
2996                 /*
2997                  * Skip EFIs that we've already processed.
2998                  */
2999                 efip = (xfs_efi_log_item_t *)lip;
3000                 if (test_bit(XFS_EFI_RECOVERED, &efip->efi_flags)) {
3001                         lip = xfs_trans_ail_cursor_next(ailp, &cur);
3002                         continue;
3003                 }
3004 
3005                 spin_unlock(&ailp->xa_lock);
3006                 error = xlog_recover_process_efi(log->l_mp, efip);
3007                 spin_lock(&ailp->xa_lock);
3008                 if (error)
3009                         goto out;
3010                 lip = xfs_trans_ail_cursor_next(ailp, &cur);
3011         }
3012 out:
3013         xfs_trans_ail_cursor_done(ailp, &cur);
3014         spin_unlock(&ailp->xa_lock);
3015         return error;
3016 }
3017 
3018 /*
3019  * This routine performs a transaction to null out a bad inode pointer
3020  * in an agi unlinked inode hash bucket.
3021  */
3022 STATIC void
3023 xlog_recover_clear_agi_bucket(
3024         xfs_mount_t     *mp,
3025         xfs_agnumber_t  agno,
3026         int             bucket)
3027 {
3028         xfs_trans_t     *tp;
3029         xfs_agi_t       *agi;
3030         xfs_buf_t       *agibp;
3031         int             offset;
3032         int             error;
3033 
3034         tp = xfs_trans_alloc(mp, XFS_TRANS_CLEAR_AGI_BUCKET);
3035         error = xfs_trans_reserve(tp, 0, XFS_CLEAR_AGI_BUCKET_LOG_RES(mp),
3036                                   0, 0, 0);
3037         if (error)
3038                 goto out_abort;
3039 
3040         error = xfs_read_agi(mp, tp, agno, &agibp);
3041         if (error)
3042                 goto out_abort;
3043 
3044         agi = XFS_BUF_TO_AGI(agibp);
3045         agi->agi_unlinked[bucket] = cpu_to_be32(NULLAGINO);
3046         offset = offsetof(xfs_agi_t, agi_unlinked) +
3047                  (sizeof(xfs_agino_t) * bucket);
3048         xfs_trans_log_buf(tp, agibp, offset,
3049                           (offset + sizeof(xfs_agino_t) - 1));
3050 
3051         error = xfs_trans_commit(tp, 0);
3052         if (error)
3053                 goto out_error;
3054         return;
3055 
3056 out_abort:
3057         xfs_trans_cancel(tp, XFS_TRANS_ABORT);
3058 out_error:
3059         xfs_warn(mp, "%s: failed to clear agi %d. Continuing.", __func__, agno);
3060         return;
3061 }
3062 
3063 STATIC xfs_agino_t
3064 xlog_recover_process_one_iunlink(
3065         struct xfs_mount                *mp,
3066         xfs_agnumber_t                  agno,
3067         xfs_agino_t                     agino,
3068         int                             bucket)
3069 {
3070         struct xfs_buf                  *ibp;
3071         struct xfs_dinode               *dip;
3072         struct xfs_inode                *ip;
3073         xfs_ino_t                       ino;
3074         int                             error;
3075 
3076         ino = XFS_AGINO_TO_INO(mp, agno, agino);
3077         error = xfs_iget(mp, NULL, ino, 0, 0, &ip);
3078         if (error)
3079                 goto fail;
3080 
3081         /*
3082          * Get the on disk inode to find the next inode in the bucket.
3083          */
3084         error = xfs_itobp(mp, NULL, ip, &dip, &ibp, XBF_LOCK);
3085         if (error)
3086                 goto fail_iput;
3087 
3088         ASSERT(ip->i_d.di_nlink == 0);
3089         ASSERT(ip->i_d.di_mode != 0);
3090 
3091         /* setup for the next pass */
3092         agino = be32_to_cpu(dip->di_next_unlinked);
3093         xfs_buf_relse(ibp);
3094 
3095         /*
3096          * Prevent any DMAPI event from being sent when the reference on
3097          * the inode is dropped.
3098          */
3099         ip->i_d.di_dmevmask = 0;
3100 
3101         IRELE(ip);
3102         return agino;
3103 
3104  fail_iput:
3105         IRELE(ip);
3106  fail:
3107         /*
3108          * We can't read in the inode this bucket points to, or this inode
3109          * is messed up.  Just ditch this bucket of inodes.  We will lose
3110          * some inodes and space, but at least we won't hang.
3111          *
3112          * Call xlog_recover_clear_agi_bucket() to perform a transaction to
3113          * clear the inode pointer in the bucket.
3114          */
3115         xlog_recover_clear_agi_bucket(mp, agno, bucket);
3116         return NULLAGINO;
3117 }
3118 
3119 /*
3120  * xlog_iunlink_recover
3121  *
3122  * This is called during recovery to process any inodes which
3123  * we unlinked but not freed when the system crashed.  These
3124  * inodes will be on the lists in the AGI blocks.  What we do
3125  * here is scan all the AGIs and fully truncate and free any
3126  * inodes found on the lists.  Each inode is removed from the
3127  * lists when it has been fully truncated and is freed.  The
3128  * freeing of the inode and its removal from the list must be
3129  * atomic.
3130  */
3131 STATIC void
3132 xlog_recover_process_iunlinks(
3133         xlog_t          *log)
3134 {
3135         xfs_mount_t     *mp;
3136         xfs_agnumber_t  agno;
3137         xfs_agi_t       *agi;
3138         xfs_buf_t       *agibp;
3139         xfs_agino_t     agino;
3140         int             bucket;
3141         int             error;
3142         uint            mp_dmevmask;
3143 
3144         mp = log->l_mp;
3145 
3146         /*
3147          * Prevent any DMAPI event from being sent while in this function.
3148          */
3149         mp_dmevmask = mp->m_dmevmask;
3150         mp->m_dmevmask = 0;
3151 
3152         for (agno = 0; agno < mp->m_sb.sb_agcount; agno++) {
3153                 /*
3154                  * Find the agi for this ag.
3155                  */
3156                 error = xfs_read_agi(mp, NULL, agno, &agibp);
3157                 if (error) {
3158                         /*
3159                          * AGI is b0rked. Don't process it.
3160                          *
3161                          * We should probably mark the filesystem as corrupt
3162                          * after we've recovered all the ag's we can....
3163                          */
3164                         continue;
3165                 }
3166                 agi = XFS_BUF_TO_AGI(agibp);
3167 
3168                 for (bucket = 0; bucket < XFS_AGI_UNLINKED_BUCKETS; bucket++) {
3169                         agino = be32_to_cpu(agi->agi_unlinked[bucket]);
3170                         while (agino != NULLAGINO) {
3171                                 /*
3172                                  * Release the agi buffer so that it can
3173                                  * be acquired in the normal course of the
3174                                  * transaction to truncate and free the inode.
3175                                  */
3176                                 xfs_buf_relse(agibp);
3177 
3178                                 agino = xlog_recover_process_one_iunlink(mp,
3179                                                         agno, agino, bucket);
3180 
3181                                 /*
3182                                  * Reacquire the agibuffer and continue around
3183                                  * the loop. This should never fail as we know
3184                                  * the buffer was good earlier on.
3185                                  */
3186                                 error = xfs_read_agi(mp, NULL, agno, &agibp);
3187                                 ASSERT(error == 0);
3188                                 agi = XFS_BUF_TO_AGI(agibp);
3189                         }
3190                 }
3191 
3192                 /*
3193                  * Release the buffer for the current agi so we can
3194                  * go on to the next one.
3195                  */
3196                 xfs_buf_relse(agibp);
3197         }
3198 
3199         mp->m_dmevmask = mp_dmevmask;
3200 }
3201 
3202 
3203 #ifdef DEBUG
3204 STATIC void
3205 xlog_pack_data_checksum(
3206         xlog_t          *log,
3207         xlog_in_core_t  *iclog,
3208         int             size)
3209 {
3210         int             i;
3211         __be32          *up;
3212         uint            chksum = 0;
3213 
3214         up = (__be32 *)iclog->ic_datap;
3215         /* divide length by 4 to get # words */
3216         for (i = 0; i < (size >> 2); i++) {
3217                 chksum ^= be32_to_cpu(*up);
3218                 up++;
3219         }
3220         iclog->ic_header.h_chksum = cpu_to_be32(chksum);
3221 }
3222 #else
3223 #define xlog_pack_data_checksum(log, iclog, size)
3224 #endif
3225 
3226 /*
3227  * Stamp cycle number in every block
3228  */
3229 void
3230 xlog_pack_data(
3231         xlog_t                  *log,
3232         xlog_in_core_t          *iclog,
3233         int                     roundoff)
3234 {
3235         int                     i, j, k;
3236         int                     size = iclog->ic_offset + roundoff;
3237         __be32                  cycle_lsn;
3238         xfs_caddr_t             dp;
3239 
3240         xlog_pack_data_checksum(log, iclog, size);
3241 
3242         cycle_lsn = CYCLE_LSN_DISK(iclog->ic_header.h_lsn);
3243 
3244         dp = iclog->ic_datap;
3245         for (i = 0; i < BTOBB(size) &&
3246                 i < (XLOG_HEADER_CYCLE_SIZE / BBSIZE); i++) {
3247                 iclog->ic_header.h_cycle_data[i] = *(__be32 *)dp;
3248                 *(__be32 *)dp = cycle_lsn;
3249                 dp += BBSIZE;
3250         }
3251 
3252         if (xfs_sb_version_haslogv2(&log->l_mp->m_sb)) {
3253                 xlog_in_core_2_t *xhdr = iclog->ic_data;
3254 
3255                 for ( ; i < BTOBB(size); i++) {
3256                         j = i / (XLOG_HEADER_CYCLE_SIZE / BBSIZE);
3257                         k = i % (XLOG_HEADER_CYCLE_SIZE / BBSIZE);
3258                         xhdr[j].hic_xheader.xh_cycle_data[k] = *(__be32 *)dp;
3259                         *(__be32 *)dp = cycle_lsn;
3260                         dp += BBSIZE;
3261                 }
3262 
3263                 for (i = 1; i < log->l_iclog_heads; i++) {
3264                         xhdr[i].hic_xheader.xh_cycle = cycle_lsn;
3265                 }
3266         }
3267 }
3268 
3269 STATIC void
3270 xlog_unpack_data(
3271         xlog_rec_header_t       *rhead,
3272         xfs_caddr_t             dp,
3273         xlog_t                  *log)
3274 {
3275         int                     i, j, k;
3276 
3277         for (i = 0; i < BTOBB(be32_to_cpu(rhead->h_len)) &&
3278                   i < (XLOG_HEADER_CYCLE_SIZE / BBSIZE); i++) {
3279                 *(__be32 *)dp = *(__be32 *)&rhead->h_cycle_data[i];
3280                 dp += BBSIZE;
3281         }
3282 
3283         if (xfs_sb_version_haslogv2(&log->l_mp->m_sb)) {
3284                 xlog_in_core_2_t *xhdr = (xlog_in_core_2_t *)rhead;
3285                 for ( ; i < BTOBB(be32_to_cpu(rhead->h_len)); i++) {
3286                         j = i / (XLOG_HEADER_CYCLE_SIZE / BBSIZE);
3287                         k = i % (XLOG_HEADER_CYCLE_SIZE / BBSIZE);
3288                         *(__be32 *)dp = xhdr[j].hic_xheader.xh_cycle_data[k];
3289                         dp += BBSIZE;
3290                 }
3291         }
3292 }
3293 
3294 STATIC int
3295 xlog_valid_rec_header(
3296         xlog_t                  *log,
3297         xlog_rec_header_t       *rhead,
3298         xfs_daddr_t             blkno)
3299 {
3300         int                     hlen;
3301 
3302         if (unlikely(rhead->h_magicno != cpu_to_be32(XLOG_HEADER_MAGIC_NUM))) {
3303                 XFS_ERROR_REPORT("xlog_valid_rec_header(1)",
3304                                 XFS_ERRLEVEL_LOW, log->l_mp);
3305                 return XFS_ERROR(EFSCORRUPTED);
3306         }
3307         if (unlikely(
3308             (!rhead->h_version ||
3309             (be32_to_cpu(rhead->h_version) & (~XLOG_VERSION_OKBITS))))) {
3310                 xfs_warn(log->l_mp, "%s: unrecognised log version (%d).",
3311                         __func__, be32_to_cpu(rhead->h_version));
3312                 return XFS_ERROR(EIO);
3313         }
3314 
3315         /* LR body must have data or it wouldn't have been written */
3316         hlen = be32_to_cpu(rhead->h_len);
3317         if (unlikely( hlen <= 0 || hlen > INT_MAX )) {
3318                 XFS_ERROR_REPORT("xlog_valid_rec_header(2)",
3319                                 XFS_ERRLEVEL_LOW, log->l_mp);
3320                 return XFS_ERROR(EFSCORRUPTED);
3321         }
3322         if (unlikely( blkno > log->l_logBBsize || blkno > INT_MAX )) {
3323                 XFS_ERROR_REPORT("xlog_valid_rec_header(3)",
3324                                 XFS_ERRLEVEL_LOW, log->l_mp);
3325                 return XFS_ERROR(EFSCORRUPTED);
3326         }
3327         return 0;
3328 }
3329 
3330 /*
3331  * Read the log from tail to head and process the log records found.
3332  * Handle the two cases where the tail and head are in the same cycle
3333  * and where the active portion of the log wraps around the end of
3334  * the physical log separately.  The pass parameter is passed through
3335  * to the routines called to process the data and is not looked at
3336  * here.
3337  */
3338 STATIC int
3339 xlog_do_recovery_pass(
3340         xlog_t                  *log,
3341         xfs_daddr_t             head_blk,
3342         xfs_daddr_t             tail_blk,
3343         int                     pass)
3344 {
3345         xlog_rec_header_t       *rhead;
3346         xfs_daddr_t             blk_no;
3347         xfs_caddr_t             offset;
3348         xfs_buf_t               *hbp, *dbp;
3349         int                     error = 0, h_size;
3350         int                     bblks, split_bblks;
3351         int                     hblks, split_hblks, wrapped_hblks;
3352         struct hlist_head       rhash[XLOG_RHASH_SIZE];
3353 
3354         ASSERT(head_blk != tail_blk);
3355 
3356         /*
3357          * Read the header of the tail block and get the iclog buffer size from
3358          * h_size.  Use this to tell how many sectors make up the log header.
3359          */
3360         if (xfs_sb_version_haslogv2(&log->l_mp->m_sb)) {
3361                 /*
3362                  * When using variable length iclogs, read first sector of
3363                  * iclog header and extract the header size from it.  Get a
3364                  * new hbp that is the correct size.
3365                  */
3366                 hbp = xlog_get_bp(log, 1);
3367                 if (!hbp)
3368                         return ENOMEM;
3369 
3370                 error = xlog_bread(log, tail_blk, 1, hbp, &offset);
3371                 if (error)
3372                         goto bread_err1;
3373 
3374                 rhead = (xlog_rec_header_t *)offset;
3375                 error = xlog_valid_rec_header(log, rhead, tail_blk);
3376                 if (error)
3377                         goto bread_err1;
3378                 h_size = be32_to_cpu(rhead->h_size);
3379                 if ((be32_to_cpu(rhead->h_version) & XLOG_VERSION_2) &&
3380                     (h_size > XLOG_HEADER_CYCLE_SIZE)) {
3381                         hblks = h_size / XLOG_HEADER_CYCLE_SIZE;
3382                         if (h_size % XLOG_HEADER_CYCLE_SIZE)
3383                                 hblks++;
3384                         xlog_put_bp(hbp);
3385                         hbp = xlog_get_bp(log, hblks);
3386                 } else {
3387                         hblks = 1;
3388                 }
3389         } else {
3390                 ASSERT(log->l_sectBBsize == 1);
3391                 hblks = 1;
3392                 hbp = xlog_get_bp(log, 1);
3393                 h_size = XLOG_BIG_RECORD_BSIZE;
3394         }
3395 
3396         if (!hbp)
3397                 return ENOMEM;
3398         dbp = xlog_get_bp(log, BTOBB(h_size));
3399         if (!dbp) {
3400                 xlog_put_bp(hbp);
3401                 return ENOMEM;
3402         }
3403 
3404         memset(rhash, 0, sizeof(rhash));
3405         if (tail_blk <= head_blk) {
3406                 for (blk_no = tail_blk; blk_no < head_blk; ) {
3407                         error = xlog_bread(log, blk_no, hblks, hbp, &offset);
3408                         if (error)
3409                                 goto bread_err2;
3410 
3411                         rhead = (xlog_rec_header_t *)offset;
3412                         error = xlog_valid_rec_header(log, rhead, blk_no);
3413                         if (error)
3414                                 goto bread_err2;
3415 
3416                         /* blocks in data section */
3417                         bblks = (int)BTOBB(be32_to_cpu(rhead->h_len));
3418                         error = xlog_bread(log, blk_no + hblks, bblks, dbp,
3419                                            &offset);
3420                         if (error)
3421                                 goto bread_err2;
3422 
3423                         xlog_unpack_data(rhead, offset, log);
3424                         if ((error = xlog_recover_process_data(log,
3425                                                 rhash, rhead, offset, pass)))
3426                                 goto bread_err2;
3427                         blk_no += bblks + hblks;
3428                 }
3429         } else {
3430                 /*
3431                  * Perform recovery around the end of the physical log.
3432                  * When the head is not on the same cycle number as the tail,
3433                  * we can't do a sequential recovery as above.
3434                  */
3435                 blk_no = tail_blk;
3436                 while (blk_no < log->l_logBBsize) {
3437                         /*
3438                          * Check for header wrapping around physical end-of-log
3439                          */
3440                         offset = hbp->b_addr;
3441                         split_hblks = 0;
3442                         wrapped_hblks = 0;
3443                         if (blk_no + hblks <= log->l_logBBsize) {
3444                                 /* Read header in one read */
3445                                 error = xlog_bread(log, blk_no, hblks, hbp,
3446                                                    &offset);
3447                                 if (error)
3448                                         goto bread_err2;
3449                         } else {
3450                                 /* This LR is split across physical log end */
3451                                 if (blk_no != log->l_logBBsize) {
3452                                         /* some data before physical log end */
3453                                         ASSERT(blk_no <= INT_MAX);
3454                                         split_hblks = log->l_logBBsize - (int)blk_no;
3455                                         ASSERT(split_hblks > 0);
3456                                         error = xlog_bread(log, blk_no,
3457                                                            split_hblks, hbp,
3458                                                            &offset);
3459                                         if (error)
3460                                                 goto bread_err2;
3461                                 }
3462 
3463                                 /*
3464                                  * Note: this black magic still works with
3465                                  * large sector sizes (non-512) only because:
3466                                  * - we increased the buffer size originally
3467                                  *   by 1 sector giving us enough extra space
3468                                  *   for the second read;
3469                                  * - the log start is guaranteed to be sector
3470                                  *   aligned;
3471                                  * - we read the log end (LR header start)
3472                                  *   _first_, then the log start (LR header end)
3473                                  *   - order is important.
3474                                  */
3475                                 wrapped_hblks = hblks - split_hblks;
3476                                 error = xlog_bread_offset(log, 0,
3477                                                 wrapped_hblks, hbp,
3478                                                 offset + BBTOB(split_hblks));
3479                                 if (error)
3480                                         goto bread_err2;
3481                         }
3482                         rhead = (xlog_rec_header_t *)offset;
3483                         error = xlog_valid_rec_header(log, rhead,
3484                                                 split_hblks ? blk_no : 0);
3485                         if (error)
3486                                 goto bread_err2;
3487 
3488                         bblks = (int)BTOBB(be32_to_cpu(rhead->h_len));
3489                         blk_no += hblks;
3490 
3491                         /* Read in data for log record */
3492                         if (blk_no + bblks <= log->l_logBBsize) {
3493                                 error = xlog_bread(log, blk_no, bblks, dbp,
3494                                                    &offset);
3495                                 if (error)
3496                                         goto bread_err2;
3497                         } else {
3498                                 /* This log record is split across the
3499                                  * physical end of log */
3500                                 offset = dbp->b_addr;
3501                                 split_bblks = 0;
3502                                 if (blk_no != log->l_logBBsize) {
3503                                         /* some data is before the physical
3504                                          * end of log */
3505                                         ASSERT(!wrapped_hblks);
3506                                         ASSERT(blk_no <= INT_MAX);
3507                                         split_bblks =
3508                                                 log->l_logBBsize - (int)blk_no;
3509                                         ASSERT(split_bblks > 0);
3510                                         error = xlog_bread(log, blk_no,
3511                                                         split_bblks, dbp,
3512                                                         &offset);
3513                                         if (error)
3514                                                 goto bread_err2;
3515                                 }
3516 
3517                                 /*
3518                                  * Note: this black magic still works with
3519                                  * large sector sizes (non-512) only because:
3520                                  * - we increased the buffer size originally
3521                                  *   by 1 sector giving us enough extra space
3522                                  *   for the second read;
3523                                  * - the log start is guaranteed to be sector
3524                                  *   aligned;
3525                                  * - we read the log end (LR header start)
3526                                  *   _first_, then the log start (LR header end)
3527                                  *   - order is important.
3528                                  */
3529                                 error = xlog_bread_offset(log, 0,
3530                                                 bblks - split_bblks, hbp,
3531                                                 offset + BBTOB(split_bblks));
3532                                 if (error)
3533                                         goto bread_err2;
3534                         }
3535                         xlog_unpack_data(rhead, offset, log);
3536                         if ((error = xlog_recover_process_data(log, rhash,
3537                                                         rhead, offset, pass)))
3538                                 goto bread_err2;
3539                         blk_no += bblks;
3540                 }
3541 
3542                 ASSERT(blk_no >= log->l_logBBsize);
3543                 blk_no -= log->l_logBBsize;
3544 
3545                 /* read first part of physical log */
3546                 while (blk_no < head_blk) {
3547                         error = xlog_bread(log, blk_no, hblks, hbp, &offset);
3548                         if (error)
3549                                 goto bread_err2;
3550 
3551                         rhead = (xlog_rec_header_t *)offset;
3552                         error = xlog_valid_rec_header(log, rhead, blk_no);
3553                         if (error)
3554                                 goto bread_err2;
3555 
3556                         bblks = (int)BTOBB(be32_to_cpu(rhead->h_len));
3557                         error = xlog_bread(log, blk_no+hblks, bblks, dbp,
3558                                            &offset);
3559                         if (error)
3560                                 goto bread_err2;
3561 
3562                         xlog_unpack_data(rhead, offset, log);
3563                         if ((error = xlog_recover_process_data(log, rhash,
3564                                                         rhead, offset, pass)))
3565                                 goto bread_err2;
3566                         blk_no += bblks + hblks;
3567                 }
3568         }
3569 
3570  bread_err2:
3571         xlog_put_bp(dbp);
3572  bread_err1:
3573         xlog_put_bp(hbp);
3574         return error;
3575 }
3576 
3577 /*
3578  * Do the recovery of the log.  We actually do this in two phases.
3579  * The two passes are necessary in order to implement the function
3580  * of cancelling a record written into the log.  The first pass
3581  * determines those things which have been cancelled, and the
3582  * second pass replays log items normally except for those which
3583  * have been cancelled.  The handling of the replay and cancellations
3584  * takes place in the log item type specific routines.
3585  *
3586  * The table of items which have cancel records in the log is allocated
3587  * and freed at this level, since only here do we know when all of
3588  * the log recovery has been completed.
3589  */
3590 STATIC int
3591 xlog_do_log_recovery(
3592         xlog_t          *log,
3593         xfs_daddr_t     head_blk,
3594         xfs_daddr_t     tail_blk)
3595 {
3596         int             error, i;
3597 
3598         ASSERT(head_blk != tail_blk);
3599 
3600         /*
3601          * First do a pass to find all of the cancelled buf log items.
3602          * Store them in the buf_cancel_table for use in the second pass.
3603          */
3604         log->l_buf_cancel_table = kmem_zalloc(XLOG_BC_TABLE_SIZE *
3605                                                  sizeof(struct list_head),
3606                                                  KM_SLEEP);
3607         for (i = 0; i < XLOG_BC_TABLE_SIZE; i++)
3608                 INIT_LIST_HEAD(&log->l_buf_cancel_table[i]);
3609 
3610         error = xlog_do_recovery_pass(log, head_blk, tail_blk,
3611                                       XLOG_RECOVER_PASS1);
3612         if (error != 0) {
3613                 kmem_free(log->l_buf_cancel_table);
3614                 log->l_buf_cancel_table = NULL;
3615                 return error;
3616         }
3617         /*
3618          * Then do a second pass to actually recover the items in the log.
3619          * When it is complete free the table of buf cancel items.
3620          */
3621         error = xlog_do_recovery_pass(log, head_blk, tail_blk,
3622                                       XLOG_RECOVER_PASS2);
3623 #ifdef DEBUG
3624         if (!error) {
3625                 int     i;
3626 
3627                 for (i = 0; i < XLOG_BC_TABLE_SIZE; i++)
3628                         ASSERT(list_empty(&log->l_buf_cancel_table[i]));
3629         }
3630 #endif  /* DEBUG */
3631 
3632         kmem_free(log->l_buf_cancel_table);
3633         log->l_buf_cancel_table = NULL;
3634 
3635         return error;
3636 }
3637 
3638 /*
3639  * Do the actual recovery
3640  */
3641 STATIC int
3642 xlog_do_recover(
3643         xlog_t          *log,
3644         xfs_daddr_t     head_blk,
3645         xfs_daddr_t     tail_blk)
3646 {
3647         int             error;
3648         xfs_buf_t       *bp;
3649         xfs_sb_t        *sbp;
3650 
3651         /*
3652          * First replay the images in the log.
3653          */
3654         error = xlog_do_log_recovery(log, head_blk, tail_blk);
3655         if (error) {
3656                 return error;
3657         }
3658 
3659         XFS_bflush(log->l_mp->m_ddev_targp);
3660 
3661         /*
3662          * If IO errors happened during recovery, bail out.
3663          */
3664         if (XFS_FORCED_SHUTDOWN(log->l_mp)) {
3665                 return (EIO);
3666         }
3667 
3668         /*
3669          * We now update the tail_lsn since much of the recovery has completed
3670          * and there may be space available to use.  If there were no extent
3671          * or iunlinks, we can free up the entire log and set the tail_lsn to
3672          * be the last_sync_lsn.  This was set in xlog_find_tail to be the
3673          * lsn of the last known good LR on disk.  If there are extent frees
3674          * or iunlinks they will have some entries in the AIL; so we look at
3675          * the AIL to determine how to set the tail_lsn.
3676          */
3677         xlog_assign_tail_lsn(log->l_mp);
3678 
3679         /*
3680          * Now that we've finished replaying all buffer and inode
3681          * updates, re-read in the superblock.
3682          */
3683         bp = xfs_getsb(log->l_mp, 0);
3684         XFS_BUF_UNDONE(bp);
3685         ASSERT(!(XFS_BUF_ISWRITE(bp)));
3686         ASSERT(!(XFS_BUF_ISDELAYWRITE(bp)));
3687         XFS_BUF_READ(bp);
3688         XFS_BUF_UNASYNC(bp);
3689         xfsbdstrat(log->l_mp, bp);
3690         error = xfs_buf_iowait(bp);
3691         if (error) {
3692                 xfs_ioerror_alert("xlog_do_recover",
3693                                   log->l_mp, bp, XFS_BUF_ADDR(bp));
3694                 ASSERT(0);
3695                 xfs_buf_relse(bp);
3696                 return error;
3697         }
3698 
3699         /* Convert superblock from on-disk format */
3700         sbp = &log->l_mp->m_sb;
3701         xfs_sb_from_disk(sbp, XFS_BUF_TO_SBP(bp));
3702         ASSERT(sbp->sb_magicnum == XFS_SB_MAGIC);
3703         ASSERT(xfs_sb_good_version(sbp));
3704         xfs_buf_relse(bp);
3705 
3706         /* We've re-read the superblock so re-initialize per-cpu counters */
3707         xfs_icsb_reinit_counters(log->l_mp);
3708 
3709         xlog_recover_check_summary(log);
3710 
3711         /* Normal transactions can now occur */
3712         log->l_flags &= ~XLOG_ACTIVE_RECOVERY;
3713         return 0;
3714 }
3715 
3716 /*
3717  * Perform recovery and re-initialize some log variables in xlog_find_tail.
3718  *
3719  * Return error or zero.
3720  */
3721 int
3722 xlog_recover(
3723         xlog_t          *log)
3724 {
3725         xfs_daddr_t     head_blk, tail_blk;
3726         int             error;
3727 
3728         /* find the tail of the log */
3729         if ((error = xlog_find_tail(log, &head_blk, &tail_blk)))
3730                 return error;
3731 
3732         if (tail_blk != head_blk) {
3733                 /* There used to be a comment here:
3734                  *
3735                  * disallow recovery on read-only mounts.  note -- mount
3736                  * checks for ENOSPC and turns it into an intelligent
3737                  * error message.
3738                  * ...but this is no longer true.  Now, unless you specify
3739                  * NORECOVERY (in which case this function would never be
3740                  * called), we just go ahead and recover.  We do this all
3741                  * under the vfs layer, so we can get away with it unless
3742                  * the device itself is read-only, in which case we fail.
3743                  */
3744                 if ((error = xfs_dev_is_read_only(log->l_mp, "recovery"))) {
3745                         return error;
3746                 }
3747 
3748                 xfs_notice(log->l_mp, "Starting recovery (logdev: %s)",
3749                                 log->l_mp->m_logname ? log->l_mp->m_logname
3750                                                      : "internal");
3751 
3752                 error = xlog_do_recover(log, head_blk, tail_blk);
3753                 log->l_flags |= XLOG_RECOVERY_NEEDED;
3754         }
3755         return error;
3756 }
3757 
3758 /*
3759  * In the first part of recovery we replay inodes and buffers and build
3760  * up the list of extent free items which need to be processed.  Here
3761  * we process the extent free items and clean up the on disk unlinked
3762  * inode lists.  This is separated from the first part of recovery so
3763  * that the root and real-time bitmap inodes can be read in from disk in
3764  * between the two stages.  This is necessary so that we can free space
3765  * in the real-time portion of the file system.
3766  */
3767 int
3768 xlog_recover_finish(
3769         xlog_t          *log)
3770 {
3771         /*
3772          * Now we're ready to do the transactions needed for the
3773          * rest of recovery.  Start with completing all the extent
3774          * free intent records and then process the unlinked inode
3775          * lists.  At this point, we essentially run in normal mode
3776          * except that we're still performing recovery actions
3777          * rather than accepting new requests.
3778          */
3779         if (log->l_flags & XLOG_RECOVERY_NEEDED) {
3780                 int     error;
3781                 error = xlog_recover_process_efis(log);
3782                 if (error) {
3783                         xfs_alert(log->l_mp, "Failed to recover EFIs");
3784                         return error;
3785                 }
3786                 /*
3787                  * Sync the log to get all the EFIs out of the AIL.
3788                  * This isn't absolutely necessary, but it helps in
3789                  * case the unlink transactions would have problems
3790                  * pushing the EFIs out of the way.
3791                  */
3792                 xfs_log_force(log->l_mp, XFS_LOG_SYNC);
3793 
3794                 xlog_recover_process_iunlinks(log);
3795 
3796                 xlog_recover_check_summary(log);
3797 
3798                 xfs_notice(log->l_mp, "Ending recovery (logdev: %s)",
3799                                 log->l_mp->m_logname ? log->l_mp->m_logname
3800                                                      : "internal");
3801                 log->l_flags &= ~XLOG_RECOVERY_NEEDED;
3802         } else {
3803                 xfs_info(log->l_mp, "Ending clean mount");
3804         }
3805         return 0;
3806 }
3807 
3808 
3809 #if defined(DEBUG)
3810 /*
3811  * Read all of the agf and agi counters and check that they
3812  * are consistent with the superblock counters.
3813  */
3814 void
3815 xlog_recover_check_summary(
3816         xlog_t          *log)
3817 {
3818         xfs_mount_t     *mp;
3819         xfs_agf_t       *agfp;
3820         xfs_buf_t       *agfbp;
3821         xfs_buf_t       *agibp;
3822         xfs_agnumber_t  agno;
3823         __uint64_t      freeblks;
3824         __uint64_t      itotal;
3825         __uint64_t      ifree;
3826         int             error;
3827 
3828         mp = log->l_mp;
3829 
3830         freeblks = 0LL;
3831         itotal = 0LL;
3832         ifree = 0LL;
3833         for (agno = 0; agno < mp->m_sb.sb_agcount; agno++) {
3834                 error = xfs_read_agf(mp, NULL, agno, 0, &agfbp);
3835                 if (error) {
3836                         xfs_alert(mp, "%s agf read failed agno %d error %d",
3837                                                 __func__, agno, error);
3838                 } else {
3839                         agfp = XFS_BUF_TO_AGF(agfbp);
3840                         freeblks += be32_to_cpu(agfp->agf_freeblks) +
3841                                     be32_to_cpu(agfp->agf_flcount);
3842                         xfs_buf_relse(agfbp);
3843                 }
3844 
3845                 error = xfs_read_agi(mp, NULL, agno, &agibp);
3846                 if (error) {
3847                         xfs_alert(mp, "%s agi read failed agno %d error %d",
3848                                                 __func__, agno, error);
3849                 } else {
3850                         struct xfs_agi  *agi = XFS_BUF_TO_AGI(agibp);
3851 
3852                         itotal += be32_to_cpu(agi->agi_count);
3853                         ifree += be32_to_cpu(agi->agi_freecount);
3854                         xfs_buf_relse(agibp);
3855                 }
3856         }
3857 }
3858 #endif /* DEBUG */
3859 

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