LCOV - code coverage report
Current view: top level - fs/xfs - xfs_log_recover.c (source / functions) Hit Total Coverage
Test: fstests of 6.5.0-rc3-djwx @ Mon Jul 31 20:08:22 PDT 2023 Lines: 1052 1288 81.7 %
Date: 2023-07-31 20:08:22 Functions: 55 56 98.2 %

          Line data    Source code
       1             : // SPDX-License-Identifier: GPL-2.0
       2             : /*
       3             :  * Copyright (c) 2000-2006 Silicon Graphics, Inc.
       4             :  * All Rights Reserved.
       5             :  */
       6             : #include "xfs.h"
       7             : #include "xfs_fs.h"
       8             : #include "xfs_shared.h"
       9             : #include "xfs_format.h"
      10             : #include "xfs_log_format.h"
      11             : #include "xfs_trans_resv.h"
      12             : #include "xfs_bit.h"
      13             : #include "xfs_sb.h"
      14             : #include "xfs_mount.h"
      15             : #include "xfs_defer.h"
      16             : #include "xfs_inode.h"
      17             : #include "xfs_trans.h"
      18             : #include "xfs_log.h"
      19             : #include "xfs_log_priv.h"
      20             : #include "xfs_log_recover.h"
      21             : #include "xfs_trans_priv.h"
      22             : #include "xfs_alloc.h"
      23             : #include "xfs_ialloc.h"
      24             : #include "xfs_trace.h"
      25             : #include "xfs_icache.h"
      26             : #include "xfs_error.h"
      27             : #include "xfs_buf_item.h"
      28             : #include "xfs_ag.h"
      29             : #include "xfs_quota.h"
      30             : #include "xfs_reflink.h"
      31             : 
      32             : #define BLK_AVG(blk1, blk2)     ((blk1+blk2) >> 1)
      33             : 
      34             : STATIC int
      35             : xlog_find_zeroed(
      36             :         struct xlog     *,
      37             :         xfs_daddr_t     *);
      38             : STATIC int
      39             : xlog_clear_stale_blocks(
      40             :         struct xlog     *,
      41             :         xfs_lsn_t);
      42             : STATIC int
      43             : xlog_do_recovery_pass(
      44             :         struct xlog *, xfs_daddr_t, xfs_daddr_t, int, xfs_daddr_t *);
      45             : 
      46             : /*
      47             :  * Sector aligned buffer routines for buffer create/read/write/access
      48             :  */
      49             : 
      50             : /*
      51             :  * Verify the log-relative block number and length in basic blocks are valid for
      52             :  * an operation involving the given XFS log buffer. Returns true if the fields
      53             :  * are valid, false otherwise.
      54             :  */
      55             : static inline bool
      56             : xlog_verify_bno(
      57             :         struct xlog     *log,
      58             :         xfs_daddr_t     blk_no,
      59             :         int             bbcount)
      60             : {
      61    17895372 :         if (blk_no < 0 || blk_no >= log->l_logBBsize)
      62             :                 return false;
      63    18353956 :         if (bbcount <= 0 || (blk_no + bbcount) > log->l_logBBsize)
      64           0 :                 return false;
      65             :         return true;
      66             : }
      67             : 
      68             : /*
      69             :  * Allocate a buffer to hold log data.  The buffer needs to be able to map to
      70             :  * a range of nbblks basic blocks at any valid offset within the log.
      71             :  */
      72             : static char *
      73      458584 : xlog_alloc_buffer(
      74             :         struct xlog     *log,
      75             :         int             nbblks)
      76             : {
      77             :         /*
      78             :          * Pass log block 0 since we don't have an addr yet, buffer will be
      79             :          * verified on read.
      80             :          */
      81      917168 :         if (XFS_IS_CORRUPT(log->l_mp, !xlog_verify_bno(log, 0, nbblks))) {
      82           0 :                 xfs_warn(log->l_mp, "Invalid block length (0x%x) for buffer",
      83             :                         nbblks);
      84           0 :                 return NULL;
      85             :         }
      86             : 
      87             :         /*
      88             :          * We do log I/O in units of log sectors (a power-of-2 multiple of the
      89             :          * basic block size), so we round up the requested size to accommodate
      90             :          * the basic blocks required for complete log sectors.
      91             :          *
      92             :          * In addition, the buffer may be used for a non-sector-aligned block
      93             :          * offset, in which case an I/O of the requested size could extend
      94             :          * beyond the end of the buffer.  If the requested size is only 1 basic
      95             :          * block it will never straddle a sector boundary, so this won't be an
      96             :          * issue.  Nor will this be a problem if the log I/O is done in basic
      97             :          * blocks (sector size 1).  But otherwise we extend the buffer by one
      98             :          * extra log sector to ensure there's space to accommodate this
      99             :          * possibility.
     100             :          */
     101      458584 :         if (nbblks > 1 && log->l_sectBBsize > 1)
     102      168073 :                 nbblks += log->l_sectBBsize;
     103      458584 :         nbblks = round_up(nbblks, log->l_sectBBsize);
     104      458584 :         return kvzalloc(BBTOB(nbblks), GFP_KERNEL | __GFP_RETRY_MAYFAIL);
     105             : }
     106             : 
     107             : /*
     108             :  * Return the address of the start of the given block number's data
     109             :  * in a log buffer.  The buffer covers a log sector-aligned region.
     110             :  */
     111             : static inline unsigned int
     112             : xlog_align(
     113             :         struct xlog     *log,
     114             :         xfs_daddr_t     blk_no)
     115             : {
     116    17893729 :         return BBTOB(blk_no & ((xfs_daddr_t)log->l_sectBBsize - 1));
     117             : }
     118             : 
     119             : static int
     120    17895372 : xlog_do_io(
     121             :         struct xlog             *log,
     122             :         xfs_daddr_t             blk_no,
     123             :         unsigned int            nbblks,
     124             :         char                    *data,
     125             :         enum req_op             op)
     126             : {
     127    17895372 :         int                     error;
     128             : 
     129    35790744 :         if (XFS_IS_CORRUPT(log->l_mp, !xlog_verify_bno(log, blk_no, nbblks))) {
     130           0 :                 xfs_warn(log->l_mp,
     131             :                          "Invalid log block/length (0x%llx, 0x%x) for buffer",
     132             :                          blk_no, nbblks);
     133           0 :                 return -EFSCORRUPTED;
     134             :         }
     135             : 
     136    17895372 :         blk_no = round_down(blk_no, log->l_sectBBsize);
     137    17895372 :         nbblks = round_up(nbblks, log->l_sectBBsize);
     138    17895372 :         ASSERT(nbblks > 0);
     139             : 
     140    17895372 :         error = xfs_rw_bdev(log->l_targ->bt_bdev, log->l_logBBstart + blk_no,
     141             :                         BBTOB(nbblks), data, op);
     142    17895372 :         if (error && !xlog_is_shutdown(log)) {
     143           0 :                 xfs_alert(log->l_mp,
     144             :                           "log recovery %s I/O error at daddr 0x%llx len %d error %d",
     145             :                           op == REQ_OP_WRITE ? "write" : "read",
     146             :                           blk_no, nbblks, error);
     147             :         }
     148             :         return error;
     149             : }
     150             : 
     151             : STATIC int
     152        1643 : xlog_bread_noalign(
     153             :         struct xlog     *log,
     154             :         xfs_daddr_t     blk_no,
     155             :         int             nbblks,
     156             :         char            *data)
     157             : {
     158        1643 :         return xlog_do_io(log, blk_no, nbblks, data, REQ_OP_READ);
     159             : }
     160             : 
     161             : STATIC int
     162    17403315 : xlog_bread(
     163             :         struct xlog     *log,
     164             :         xfs_daddr_t     blk_no,
     165             :         int             nbblks,
     166             :         char            *data,
     167             :         char            **offset)
     168             : {
     169    17403315 :         int             error;
     170             : 
     171    17403315 :         error = xlog_do_io(log, blk_no, nbblks, data, REQ_OP_READ);
     172    17403315 :         if (!error)
     173    17403315 :                 *offset = data + xlog_align(log, blk_no);
     174    17403315 :         return error;
     175             : }
     176             : 
     177             : STATIC int
     178      490414 : xlog_bwrite(
     179             :         struct xlog     *log,
     180             :         xfs_daddr_t     blk_no,
     181             :         int             nbblks,
     182             :         char            *data)
     183             : {
     184      490414 :         return xlog_do_io(log, blk_no, nbblks, data, REQ_OP_WRITE);
     185             : }
     186             : 
     187             : #ifdef DEBUG
     188             : /*
     189             :  * dump debug superblock and log record information
     190             :  */
     191             : STATIC void
     192           0 : xlog_header_check_dump(
     193             :         xfs_mount_t             *mp,
     194             :         xlog_rec_header_t       *head)
     195             : {
     196           0 :         xfs_debug(mp, "%s:  SB : uuid = %pU, fmt = %d",
     197             :                 __func__, &mp->m_sb.sb_uuid, XLOG_FMT);
     198           0 :         xfs_debug(mp, "    log : uuid = %pU, fmt = %d",
     199             :                 &head->h_fs_uuid, be32_to_cpu(head->h_fmt));
     200           0 : }
     201             : #else
     202             : #define xlog_header_check_dump(mp, head)
     203             : #endif
     204             : 
     205             : /*
     206             :  * check log record header for recovery
     207             :  */
     208             : STATIC int
     209     3124608 : xlog_header_check_recover(
     210             :         xfs_mount_t             *mp,
     211             :         xlog_rec_header_t       *head)
     212             : {
     213     3124608 :         ASSERT(head->h_magicno == cpu_to_be32(XLOG_HEADER_MAGIC_NUM));
     214             : 
     215             :         /*
     216             :          * IRIX doesn't write the h_fmt field and leaves it zeroed
     217             :          * (XLOG_FMT_UNKNOWN). This stops us from trying to recover
     218             :          * a dirty log created in IRIX.
     219             :          */
     220     3124608 :         if (XFS_IS_CORRUPT(mp, head->h_fmt != cpu_to_be32(XLOG_FMT))) {
     221           0 :                 xfs_warn(mp,
     222             :         "dirty log written in incompatible format - can't recover");
     223           0 :                 xlog_header_check_dump(mp, head);
     224           0 :                 return -EFSCORRUPTED;
     225             :         }
     226     3124608 :         if (XFS_IS_CORRUPT(mp, !uuid_equal(&mp->m_sb.sb_uuid,
     227             :                                            &head->h_fs_uuid))) {
     228           0 :                 xfs_warn(mp,
     229             :         "dirty log entry has mismatched uuid - can't recover");
     230           0 :                 xlog_header_check_dump(mp, head);
     231           0 :                 return -EFSCORRUPTED;
     232             :         }
     233             :         return 0;
     234             : }
     235             : 
     236             : /*
     237             :  * read the head block of the log and check the header
     238             :  */
     239             : STATIC int
     240       59215 : xlog_header_check_mount(
     241             :         xfs_mount_t             *mp,
     242             :         xlog_rec_header_t       *head)
     243             : {
     244       59215 :         ASSERT(head->h_magicno == cpu_to_be32(XLOG_HEADER_MAGIC_NUM));
     245             : 
     246       59215 :         if (uuid_is_null(&head->h_fs_uuid)) {
     247             :                 /*
     248             :                  * IRIX doesn't write the h_fs_uuid or h_fmt fields. If
     249             :                  * h_fs_uuid is null, we assume this log was last mounted
     250             :                  * by IRIX and continue.
     251             :                  */
     252           0 :                 xfs_warn(mp, "null uuid in log - IRIX style log");
     253       59215 :         } else if (XFS_IS_CORRUPT(mp, !uuid_equal(&mp->m_sb.sb_uuid,
     254             :                                                   &head->h_fs_uuid))) {
     255           0 :                 xfs_warn(mp, "log has mismatched uuid - can't recover");
     256           0 :                 xlog_header_check_dump(mp, head);
     257           0 :                 return -EFSCORRUPTED;
     258             :         }
     259             :         return 0;
     260             : }
     261             : 
     262             : /*
     263             :  * This routine finds (to an approximation) the first block in the physical
     264             :  * log which contains the given cycle.  It uses a binary search algorithm.
     265             :  * Note that the algorithm can not be perfect because the disk will not
     266             :  * necessarily be perfect.
     267             :  */
     268             : STATIC int
     269       59211 : xlog_find_cycle_start(
     270             :         struct xlog     *log,
     271             :         char            *buffer,
     272             :         xfs_daddr_t     first_blk,
     273             :         xfs_daddr_t     *last_blk,
     274             :         uint            cycle)
     275             : {
     276       59211 :         char            *offset;
     277       59211 :         xfs_daddr_t     mid_blk;
     278       59211 :         xfs_daddr_t     end_blk;
     279       59211 :         uint            mid_cycle;
     280       59211 :         int             error;
     281             : 
     282       59211 :         end_blk = *last_blk;
     283       59211 :         mid_blk = BLK_AVG(first_blk, end_blk);
     284     1077457 :         while (mid_blk != first_blk && mid_blk != end_blk) {
     285     1018246 :                 error = xlog_bread(log, mid_blk, 1, buffer, &offset);
     286     1018246 :                 if (error)
     287           0 :                         return error;
     288     1018246 :                 mid_cycle = xlog_get_cycle(offset);
     289     1018246 :                 if (mid_cycle == cycle)
     290             :                         end_blk = mid_blk;   /* last_half_cycle == mid_cycle */
     291             :                 else
     292      272371 :                         first_blk = mid_blk; /* first_half_cycle == mid_cycle */
     293     1018246 :                 mid_blk = BLK_AVG(first_blk, end_blk);
     294             :         }
     295       59211 :         ASSERT((mid_blk == first_blk && mid_blk+1 == end_blk) ||
     296             :                (mid_blk == end_blk && mid_blk-1 == first_blk));
     297             : 
     298       59211 :         *last_blk = end_blk;
     299             : 
     300       59211 :         return 0;
     301             : }
     302             : 
     303             : /*
     304             :  * Check that a range of blocks does not contain stop_on_cycle_no.
     305             :  * Fill in *new_blk with the block offset where such a block is
     306             :  * found, or with -1 (an invalid block number) if there is no such
     307             :  * block in the range.  The scan needs to occur from front to back
     308             :  * and the pointer into the region must be updated since a later
     309             :  * routine will need to perform another test.
     310             :  */
     311             : STATIC int
     312       60197 : xlog_find_verify_cycle(
     313             :         struct xlog     *log,
     314             :         xfs_daddr_t     start_blk,
     315             :         int             nbblks,
     316             :         uint            stop_on_cycle_no,
     317             :         xfs_daddr_t     *new_blk)
     318             : {
     319       60197 :         xfs_daddr_t     i, j;
     320       60197 :         uint            cycle;
     321       60197 :         char            *buffer;
     322       60197 :         xfs_daddr_t     bufblks;
     323       60197 :         char            *buf = NULL;
     324       60197 :         int             error = 0;
     325             : 
     326             :         /*
     327             :          * Greedily allocate a buffer big enough to handle the full
     328             :          * range of basic blocks we'll be examining.  If that fails,
     329             :          * try a smaller size.  We need to be able to read at least
     330             :          * a log sector, or we're out of luck.
     331             :          */
     332      120394 :         bufblks = 1 << ffs(nbblks);
     333       60197 :         while (bufblks > log->l_logBBsize)
     334           0 :                 bufblks >>= 1;
     335       60197 :         while (!(buffer = xlog_alloc_buffer(log, bufblks))) {
     336           0 :                 bufblks >>= 1;
     337           0 :                 if (bufblks < log->l_sectBBsize)
     338             :                         return -ENOMEM;
     339             :         }
     340             : 
     341     1748895 :         for (i = start_blk; i < start_blk + nbblks; i += bufblks) {
     342     1688708 :                 int     bcount;
     343             : 
     344     1688708 :                 bcount = min(bufblks, (start_blk + nbblks - i));
     345             : 
     346     1688708 :                 error = xlog_bread(log, i, bcount, buffer, &buf);
     347     1688708 :                 if (error)
     348           0 :                         goto out;
     349             : 
     350   121224019 :                 for (j = 0; j < bcount; j++) {
     351   119535321 :                         cycle = xlog_get_cycle(buf);
     352   119535321 :                         if (cycle == stop_on_cycle_no) {
     353          10 :                                 *new_blk = i+j;
     354          10 :                                 goto out;
     355             :                         }
     356             : 
     357   119535311 :                         buf += BBSIZE;
     358             :                 }
     359             :         }
     360             : 
     361       60187 :         *new_blk = -1;
     362             : 
     363       60197 : out:
     364       60197 :         kmem_free(buffer);
     365       60197 :         return error;
     366             : }
     367             : 
     368             : static inline int
     369      173402 : xlog_logrec_hblks(struct xlog *log, struct xlog_rec_header *rh)
     370             : {
     371      173402 :         if (xfs_has_logv2(log->l_mp)) {
     372      173342 :                 int     h_size = be32_to_cpu(rh->h_size);
     373             : 
     374      173342 :                 if ((be32_to_cpu(rh->h_version) & XLOG_VERSION_2) &&
     375             :                     h_size > XLOG_HEADER_CYCLE_SIZE)
     376        2231 :                         return DIV_ROUND_UP(h_size, XLOG_HEADER_CYCLE_SIZE);
     377             :         }
     378             :         return 1;
     379             : }
     380             : 
     381             : /*
     382             :  * Potentially backup over partial log record write.
     383             :  *
     384             :  * In the typical case, last_blk is the number of the block directly after
     385             :  * a good log record.  Therefore, we subtract one to get the block number
     386             :  * of the last block in the given buffer.  extra_bblks contains the number
     387             :  * of blocks we would have read on a previous read.  This happens when the
     388             :  * last log record is split over the end of the physical log.
     389             :  *
     390             :  * extra_bblks is the number of blocks potentially verified on a previous
     391             :  * call to this routine.
     392             :  */
     393             : STATIC int
     394       59238 : xlog_find_verify_log_record(
     395             :         struct xlog             *log,
     396             :         xfs_daddr_t             start_blk,
     397             :         xfs_daddr_t             *last_blk,
     398             :         int                     extra_bblks)
     399             : {
     400       59238 :         xfs_daddr_t             i;
     401       59238 :         char                    *buffer;
     402       59238 :         char                    *offset = NULL;
     403       59238 :         xlog_rec_header_t       *head = NULL;
     404       59238 :         int                     error = 0;
     405       59238 :         int                     smallmem = 0;
     406       59238 :         int                     num_blks = *last_blk - start_blk;
     407       59238 :         int                     xhdrs;
     408             : 
     409       59238 :         ASSERT(start_blk != 0 || *last_blk != start_blk);
     410             : 
     411       59238 :         buffer = xlog_alloc_buffer(log, num_blks);
     412       59238 :         if (!buffer) {
     413           0 :                 buffer = xlog_alloc_buffer(log, 1);
     414           0 :                 if (!buffer)
     415             :                         return -ENOMEM;
     416             :                 smallmem = 1;
     417             :         } else {
     418       59238 :                 error = xlog_bread(log, start_blk, num_blks, buffer, &offset);
     419       59238 :                 if (error)
     420           0 :                         goto out;
     421       59238 :                 offset += ((num_blks - 1) << BBSHIFT);
     422             :         }
     423             : 
     424      904408 :         for (i = (*last_blk) - 1; i >= 0; i--) {
     425      904405 :                 if (i < start_blk) {
     426             :                         /* valid log record not found */
     427          20 :                         xfs_warn(log->l_mp,
     428             :                 "Log inconsistent (didn't find previous header)");
     429          20 :                         ASSERT(0);
     430          20 :                         error = -EFSCORRUPTED;
     431          20 :                         goto out;
     432             :                 }
     433             : 
     434      904385 :                 if (smallmem) {
     435           0 :                         error = xlog_bread(log, i, 1, buffer, &offset);
     436           0 :                         if (error)
     437           0 :                                 goto out;
     438             :                 }
     439             : 
     440      904385 :                 head = (xlog_rec_header_t *)offset;
     441             : 
     442      904385 :                 if (head->h_magicno == cpu_to_be32(XLOG_HEADER_MAGIC_NUM))
     443             :                         break;
     444             : 
     445      845170 :                 if (!smallmem)
     446      845170 :                         offset -= BBSIZE;
     447             :         }
     448             : 
     449             :         /*
     450             :          * We hit the beginning of the physical log & still no header.  Return
     451             :          * to caller.  If caller can handle a return of -1, then this routine
     452             :          * will be called again for the end of the physical log.
     453             :          */
     454       59218 :         if (i == -1) {
     455           3 :                 error = 1;
     456           3 :                 goto out;
     457             :         }
     458             : 
     459             :         /*
     460             :          * We have the final block of the good log (the first block
     461             :          * of the log record _before_ the head. So we check the uuid.
     462             :          */
     463       59215 :         if ((error = xlog_header_check_mount(log->l_mp, head)))
     464           0 :                 goto out;
     465             : 
     466             :         /*
     467             :          * We may have found a log record header before we expected one.
     468             :          * last_blk will be the 1st block # with a given cycle #.  We may end
     469             :          * up reading an entire log record.  In this case, we don't want to
     470             :          * reset last_blk.  Only when last_blk points in the middle of a log
     471             :          * record do we update last_blk.
     472             :          */
     473       59215 :         xhdrs = xlog_logrec_hblks(log, head);
     474             : 
     475       59215 :         if (*last_blk - i + extra_bblks !=
     476       59215 :             BTOBB(be32_to_cpu(head->h_len)) + xhdrs)
     477         133 :                 *last_blk = i;
     478             : 
     479       59082 : out:
     480       59238 :         kmem_free(buffer);
     481       59238 :         return error;
     482             : }
     483             : 
     484             : /*
     485             :  * Head is defined to be the point of the log where the next log write
     486             :  * could go.  This means that incomplete LR writes at the end are
     487             :  * eliminated when calculating the head.  We aren't guaranteed that previous
     488             :  * LR have complete transactions.  We only know that a cycle number of
     489             :  * current cycle number -1 won't be present in the log if we start writing
     490             :  * from our current block number.
     491             :  *
     492             :  * last_blk contains the block number of the first block with a given
     493             :  * cycle number.
     494             :  *
     495             :  * Return: zero if normal, non-zero if error.
     496             :  */
     497             : STATIC int
     498       59235 : xlog_find_head(
     499             :         struct xlog     *log,
     500             :         xfs_daddr_t     *return_head_blk)
     501             : {
     502       59235 :         char            *buffer;
     503       59235 :         char            *offset;
     504       59235 :         xfs_daddr_t     new_blk, first_blk, start_blk, last_blk, head_blk;
     505       59235 :         int             num_scan_bblks;
     506       59235 :         uint            first_half_cycle, last_half_cycle;
     507       59235 :         uint            stop_on_cycle;
     508       59235 :         int             error, log_bbnum = log->l_logBBsize;
     509             : 
     510             :         /* Is the end of the log device zeroed? */
     511       59235 :         error = xlog_find_zeroed(log, &first_blk);
     512       59235 :         if (error < 0) {
     513           0 :                 xfs_warn(log->l_mp, "empty log check failed");
     514           0 :                 return error;
     515             :         }
     516       59235 :         if (error == 1) {
     517       36710 :                 *return_head_blk = first_blk;
     518             : 
     519             :                 /* Is the whole lot zeroed? */
     520       36710 :                 if (!first_blk) {
     521             :                         /* Linux XFS shouldn't generate totally zeroed logs -
     522             :                          * mkfs etc write a dummy unmount record to a fresh
     523             :                          * log so we can store the uuid in there
     524             :                          */
     525           0 :                         xfs_warn(log->l_mp, "totally zeroed log");
     526             :                 }
     527             : 
     528       36710 :                 return 0;
     529             :         }
     530             : 
     531       22525 :         first_blk = 0;                  /* get cycle # of 1st block */
     532       22525 :         buffer = xlog_alloc_buffer(log, 1);
     533       22525 :         if (!buffer)
     534             :                 return -ENOMEM;
     535             : 
     536       22525 :         error = xlog_bread(log, 0, 1, buffer, &offset);
     537       22525 :         if (error)
     538           0 :                 goto out_free_buffer;
     539             : 
     540       22525 :         first_half_cycle = xlog_get_cycle(offset);
     541             : 
     542       22525 :         last_blk = head_blk = log_bbnum - 1;    /* get cycle # of last block */
     543       22525 :         error = xlog_bread(log, last_blk, 1, buffer, &offset);
     544       22525 :         if (error)
     545           0 :                 goto out_free_buffer;
     546             : 
     547       22525 :         last_half_cycle = xlog_get_cycle(offset);
     548       22525 :         ASSERT(last_half_cycle != 0);
     549             : 
     550             :         /*
     551             :          * If the 1st half cycle number is equal to the last half cycle number,
     552             :          * then the entire log is stamped with the same cycle number.  In this
     553             :          * case, head_blk can't be set to zero (which makes sense).  The below
     554             :          * math doesn't work out properly with head_blk equal to zero.  Instead,
     555             :          * we set it to log_bbnum which is an invalid block number, but this
     556             :          * value makes the math correct.  If head_blk doesn't changed through
     557             :          * all the tests below, *head_blk is set to zero at the very end rather
     558             :          * than log_bbnum.  In a sense, log_bbnum and zero are the same block
     559             :          * in a circular file.
     560             :          */
     561       22525 :         if (first_half_cycle == last_half_cycle) {
     562             :                 /*
     563             :                  * In this case we believe that the entire log should have
     564             :                  * cycle number last_half_cycle.  We need to scan backwards
     565             :                  * from the end verifying that there are no holes still
     566             :                  * containing last_half_cycle - 1.  If we find such a hole,
     567             :                  * then the start of that hole will be the new head.  The
     568             :                  * simple case looks like
     569             :                  *        x | x ... | x - 1 | x
     570             :                  * Another case that fits this picture would be
     571             :                  *        x | x + 1 | x ... | x
     572             :                  * In this case the head really is somewhere at the end of the
     573             :                  * log, as one of the latest writes at the beginning was
     574             :                  * incomplete.
     575             :                  * One more case is
     576             :                  *        x | x + 1 | x ... | x - 1 | x
     577             :                  * This is really the combination of the above two cases, and
     578             :                  * the head has to end up at the start of the x-1 hole at the
     579             :                  * end of the log.
     580             :                  *
     581             :                  * In the 256k log case, we will read from the beginning to the
     582             :                  * end of the log and search for cycle numbers equal to x-1.
     583             :                  * We don't worry about the x+1 blocks that we encounter,
     584             :                  * because we know that they cannot be the head since the log
     585             :                  * started with x.
     586             :                  */
     587          24 :                 head_blk = log_bbnum;
     588          24 :                 stop_on_cycle = last_half_cycle - 1;
     589             :         } else {
     590             :                 /*
     591             :                  * In this case we want to find the first block with cycle
     592             :                  * number matching last_half_cycle.  We expect the log to be
     593             :                  * some variation on
     594             :                  *        x + 1 ... | x ... | x
     595             :                  * The first block with cycle number x (last_half_cycle) will
     596             :                  * be where the new head belongs.  First we do a binary search
     597             :                  * for the first occurrence of last_half_cycle.  The binary
     598             :                  * search may not be totally accurate, so then we scan back
     599             :                  * from there looking for occurrences of last_half_cycle before
     600             :                  * us.  If that backwards scan wraps around the beginning of
     601             :                  * the log, then we look for occurrences of last_half_cycle - 1
     602             :                  * at the end of the log.  The cases we're looking for look
     603             :                  * like
     604             :                  *                               v binary search stopped here
     605             :                  *        x + 1 ... | x | x + 1 | x ... | x
     606             :                  *                   ^ but we want to locate this spot
     607             :                  * or
     608             :                  *        <---------> less than scan distance
     609             :                  *        x + 1 ... | x ... | x - 1 | x
     610             :                  *                           ^ we want to locate this spot
     611             :                  */
     612       22501 :                 stop_on_cycle = last_half_cycle;
     613       22501 :                 error = xlog_find_cycle_start(log, buffer, first_blk, &head_blk,
     614             :                                 last_half_cycle);
     615       22501 :                 if (error)
     616           0 :                         goto out_free_buffer;
     617             :         }
     618             : 
     619             :         /*
     620             :          * Now validate the answer.  Scan back some number of maximum possible
     621             :          * blocks and make sure each one has the expected cycle number.  The
     622             :          * maximum is determined by the total possible amount of buffering
     623             :          * in the in-core log.  The following number can be made tighter if
     624             :          * we actually look at the block size of the filesystem.
     625             :          */
     626       22525 :         num_scan_bblks = min_t(int, log_bbnum, XLOG_TOTAL_REC_SHIFT(log));
     627       22525 :         if (head_blk >= num_scan_bblks) {
     628             :                 /*
     629             :                  * We are guaranteed that the entire check can be performed
     630             :                  * in one buffer.
     631             :                  */
     632       21563 :                 start_blk = head_blk - num_scan_bblks;
     633       21563 :                 if ((error = xlog_find_verify_cycle(log,
     634             :                                                 start_blk, num_scan_bblks,
     635             :                                                 stop_on_cycle, &new_blk)))
     636           0 :                         goto out_free_buffer;
     637       21563 :                 if (new_blk != -1)
     638          10 :                         head_blk = new_blk;
     639             :         } else {                /* need to read 2 parts of log */
     640             :                 /*
     641             :                  * We are going to scan backwards in the log in two parts.
     642             :                  * First we scan the physical end of the log.  In this part
     643             :                  * of the log, we are looking for blocks with cycle number
     644             :                  * last_half_cycle - 1.
     645             :                  * If we find one, then we know that the log starts there, as
     646             :                  * we've found a hole that didn't get written in going around
     647             :                  * the end of the physical log.  The simple case for this is
     648             :                  *        x + 1 ... | x ... | x - 1 | x
     649             :                  *        <---------> less than scan distance
     650             :                  * If all of the blocks at the end of the log have cycle number
     651             :                  * last_half_cycle, then we check the blocks at the start of
     652             :                  * the log looking for occurrences of last_half_cycle.  If we
     653             :                  * find one, then our current estimate for the location of the
     654             :                  * first occurrence of last_half_cycle is wrong and we move
     655             :                  * back to the hole we've found.  This case looks like
     656             :                  *        x + 1 ... | x | x + 1 | x ...
     657             :                  *                               ^ binary search stopped here
     658             :                  * Another case we need to handle that only occurs in 256k
     659             :                  * logs is
     660             :                  *        x + 1 ... | x ... | x+1 | x ...
     661             :                  *                   ^ binary search stops here
     662             :                  * In a 256k log, the scan at the end of the log will see the
     663             :                  * x + 1 blocks.  We need to skip past those since that is
     664             :                  * certainly not the head of the log.  By searching for
     665             :                  * last_half_cycle-1 we accomplish that.
     666             :                  */
     667         962 :                 ASSERT(head_blk <= INT_MAX &&
     668             :                         (xfs_daddr_t) num_scan_bblks >= head_blk);
     669         962 :                 start_blk = log_bbnum - (num_scan_bblks - head_blk);
     670         962 :                 if ((error = xlog_find_verify_cycle(log, start_blk,
     671         962 :                                         num_scan_bblks - (int)head_blk,
     672             :                                         (stop_on_cycle - 1), &new_blk)))
     673           0 :                         goto out_free_buffer;
     674         962 :                 if (new_blk != -1) {
     675           0 :                         head_blk = new_blk;
     676           0 :                         goto validate_head;
     677             :                 }
     678             : 
     679             :                 /*
     680             :                  * Scan beginning of log now.  The last part of the physical
     681             :                  * log is good.  This scan needs to verify that it doesn't find
     682             :                  * the last_half_cycle.
     683             :                  */
     684         962 :                 start_blk = 0;
     685         962 :                 ASSERT(head_blk <= INT_MAX);
     686         962 :                 if ((error = xlog_find_verify_cycle(log,
     687             :                                         start_blk, (int)head_blk,
     688             :                                         stop_on_cycle, &new_blk)))
     689           0 :                         goto out_free_buffer;
     690         962 :                 if (new_blk != -1)
     691           0 :                         head_blk = new_blk;
     692             :         }
     693             : 
     694         962 : validate_head:
     695             :         /*
     696             :          * Now we need to make sure head_blk is not pointing to a block in
     697             :          * the middle of a log record.
     698             :          */
     699       22525 :         num_scan_bblks = XLOG_REC_SHIFT(log);
     700       22525 :         if (head_blk >= num_scan_bblks) {
     701       22297 :                 start_blk = head_blk - num_scan_bblks; /* don't read head_blk */
     702             : 
     703             :                 /* start ptr at last block ptr before head_blk */
     704       22297 :                 error = xlog_find_verify_log_record(log, start_blk, &head_blk, 0);
     705       22297 :                 if (error == 1)
     706             :                         error = -EIO;
     707       22297 :                 if (error)
     708          20 :                         goto out_free_buffer;
     709             :         } else {
     710         228 :                 start_blk = 0;
     711         228 :                 ASSERT(head_blk <= INT_MAX);
     712         228 :                 error = xlog_find_verify_log_record(log, start_blk, &head_blk, 0);
     713         228 :                 if (error < 0)
     714           0 :                         goto out_free_buffer;
     715         228 :                 if (error == 1) {
     716             :                         /* We hit the beginning of the log during our search */
     717           3 :                         start_blk = log_bbnum - (num_scan_bblks - head_blk);
     718           3 :                         new_blk = log_bbnum;
     719           3 :                         ASSERT(start_blk <= INT_MAX &&
     720             :                                 (xfs_daddr_t) log_bbnum-start_blk >= 0);
     721           3 :                         ASSERT(head_blk <= INT_MAX);
     722           3 :                         error = xlog_find_verify_log_record(log, start_blk,
     723             :                                                         &new_blk, (int)head_blk);
     724           3 :                         if (error == 1)
     725             :                                 error = -EIO;
     726           3 :                         if (error)
     727           0 :                                 goto out_free_buffer;
     728           3 :                         if (new_blk != log_bbnum)
     729           0 :                                 head_blk = new_blk;
     730         225 :                 } else if (error)
     731           0 :                         goto out_free_buffer;
     732             :         }
     733             : 
     734       22505 :         kmem_free(buffer);
     735       22505 :         if (head_blk == log_bbnum)
     736           4 :                 *return_head_blk = 0;
     737             :         else
     738       22501 :                 *return_head_blk = head_blk;
     739             :         /*
     740             :          * When returning here, we have a good block number.  Bad block
     741             :          * means that during a previous crash, we didn't have a clean break
     742             :          * from cycle number N to cycle number N-1.  In this case, we need
     743             :          * to find the first block with cycle number N-1.
     744             :          */
     745             :         return 0;
     746             : 
     747          20 : out_free_buffer:
     748          20 :         kmem_free(buffer);
     749          20 :         if (error)
     750          20 :                 xfs_warn(log->l_mp, "failed to find log head");
     751          20 :         return error;
     752             : }
     753             : 
     754             : /*
     755             :  * Seek backwards in the log for log record headers.
     756             :  *
     757             :  * Given a starting log block, walk backwards until we find the provided number
     758             :  * of records or hit the provided tail block. The return value is the number of
     759             :  * records encountered or a negative error code. The log block and buffer
     760             :  * pointer of the last record seen are returned in rblk and rhead respectively.
     761             :  */
     762             : STATIC int
     763       73006 : xlog_rseek_logrec_hdr(
     764             :         struct xlog             *log,
     765             :         xfs_daddr_t             head_blk,
     766             :         xfs_daddr_t             tail_blk,
     767             :         int                     count,
     768             :         char                    *buffer,
     769             :         xfs_daddr_t             *rblk,
     770             :         struct xlog_rec_header  **rhead,
     771             :         bool                    *wrapped)
     772             : {
     773       73006 :         int                     i;
     774       73006 :         int                     error;
     775       73006 :         int                     found = 0;
     776       73006 :         char                    *offset = NULL;
     777       73006 :         xfs_daddr_t             end_blk;
     778             : 
     779       73006 :         *wrapped = false;
     780             : 
     781             :         /*
     782             :          * Walk backwards from the head block until we hit the tail or the first
     783             :          * block in the log.
     784             :          */
     785       73006 :         end_blk = head_blk > tail_blk ? tail_blk : 0;
     786     4763711 :         for (i = (int) head_blk - 1; i >= end_blk; i--) {
     787     4758045 :                 error = xlog_bread(log, i, 1, buffer, &offset);
     788     4758045 :                 if (error)
     789           0 :                         goto out_error;
     790             : 
     791     4758045 :                 if (*(__be32 *) offset == cpu_to_be32(XLOG_HEADER_MAGIC_NUM)) {
     792      137368 :                         *rblk = i;
     793      137368 :                         *rhead = (struct xlog_rec_header *) offset;
     794      137368 :                         if (++found == count)
     795             :                                 break;
     796             :                 }
     797             :         }
     798             : 
     799             :         /*
     800             :          * If we haven't hit the tail block or the log record header count,
     801             :          * start looking again from the end of the physical log. Note that
     802             :          * callers can pass head == tail if the tail is not yet known.
     803             :          */
     804       73006 :         if (tail_blk >= head_blk && found != count) {
     805       70737 :                 for (i = log->l_logBBsize - 1; i >= (int) tail_blk; i--) {
     806       70736 :                         error = xlog_bread(log, i, 1, buffer, &offset);
     807       70736 :                         if (error)
     808           0 :                                 goto out_error;
     809             : 
     810       70736 :                         if (*(__be32 *)offset ==
     811             :                             cpu_to_be32(XLOG_HEADER_MAGIC_NUM)) {
     812         265 :                                 *wrapped = true;
     813         265 :                                 *rblk = i;
     814         265 :                                 *rhead = (struct xlog_rec_header *) offset;
     815         265 :                                 if (++found == count)
     816             :                                         break;
     817             :                         }
     818             :                 }
     819             :         }
     820             : 
     821             :         return found;
     822             : 
     823             : out_error:
     824             :         return error;
     825             : }
     826             : 
     827             : /*
     828             :  * Seek forward in the log for log record headers.
     829             :  *
     830             :  * Given head and tail blocks, walk forward from the tail block until we find
     831             :  * the provided number of records or hit the head block. The return value is the
     832             :  * number of records encountered or a negative error code. The log block and
     833             :  * buffer pointer of the last record seen are returned in rblk and rhead
     834             :  * respectively.
     835             :  */
     836             : STATIC int
     837       13735 : xlog_seek_logrec_hdr(
     838             :         struct xlog             *log,
     839             :         xfs_daddr_t             head_blk,
     840             :         xfs_daddr_t             tail_blk,
     841             :         int                     count,
     842             :         char                    *buffer,
     843             :         xfs_daddr_t             *rblk,
     844             :         struct xlog_rec_header  **rhead,
     845             :         bool                    *wrapped)
     846             : {
     847       13735 :         int                     i;
     848       13735 :         int                     error;
     849       13735 :         int                     found = 0;
     850       13735 :         char                    *offset = NULL;
     851       13735 :         xfs_daddr_t             end_blk;
     852             : 
     853       13735 :         *wrapped = false;
     854             : 
     855             :         /*
     856             :          * Walk forward from the tail block until we hit the head or the last
     857             :          * block in the log.
     858             :          */
     859       13735 :         end_blk = head_blk > tail_blk ? head_blk : log->l_logBBsize - 1;
     860       13735 :         for (i = (int) tail_blk; i <= end_blk; i++) {
     861       13735 :                 error = xlog_bread(log, i, 1, buffer, &offset);
     862       13735 :                 if (error)
     863           0 :                         goto out_error;
     864             : 
     865       13735 :                 if (*(__be32 *) offset == cpu_to_be32(XLOG_HEADER_MAGIC_NUM)) {
     866       13735 :                         *rblk = i;
     867       13735 :                         *rhead = (struct xlog_rec_header *) offset;
     868       13735 :                         if (++found == count)
     869             :                                 break;
     870             :                 }
     871             :         }
     872             : 
     873             :         /*
     874             :          * If we haven't hit the head block or the log record header count,
     875             :          * start looking again from the start of the physical log.
     876             :          */
     877       13735 :         if (tail_blk > head_blk && found != count) {
     878           0 :                 for (i = 0; i < (int) head_blk; i++) {
     879           0 :                         error = xlog_bread(log, i, 1, buffer, &offset);
     880           0 :                         if (error)
     881           0 :                                 goto out_error;
     882             : 
     883           0 :                         if (*(__be32 *)offset ==
     884             :                             cpu_to_be32(XLOG_HEADER_MAGIC_NUM)) {
     885           0 :                                 *wrapped = true;
     886           0 :                                 *rblk = i;
     887           0 :                                 *rhead = (struct xlog_rec_header *) offset;
     888           0 :                                 if (++found == count)
     889             :                                         break;
     890             :                         }
     891             :                 }
     892             :         }
     893             : 
     894             :         return found;
     895             : 
     896             : out_error:
     897             :         return error;
     898             : }
     899             : 
     900             : /*
     901             :  * Calculate distance from head to tail (i.e., unused space in the log).
     902             :  */
     903             : static inline int
     904             : xlog_tail_distance(
     905             :         struct xlog     *log,
     906             :         xfs_daddr_t     head_blk,
     907             :         xfs_daddr_t     tail_blk)
     908             : {
     909           0 :         if (head_blk < tail_blk)
     910           0 :                 return tail_blk - head_blk;
     911             : 
     912           0 :         return tail_blk + (log->l_logBBsize - head_blk);
     913             : }
     914             : 
     915             : /*
     916             :  * Verify the log tail. This is particularly important when torn or incomplete
     917             :  * writes have been detected near the front of the log and the head has been
     918             :  * walked back accordingly.
     919             :  *
     920             :  * We also have to handle the case where the tail was pinned and the head
     921             :  * blocked behind the tail right before a crash. If the tail had been pushed
     922             :  * immediately prior to the crash and the subsequent checkpoint was only
     923             :  * partially written, it's possible it overwrote the last referenced tail in the
     924             :  * log with garbage. This is not a coherency problem because the tail must have
     925             :  * been pushed before it can be overwritten, but appears as log corruption to
     926             :  * recovery because we have no way to know the tail was updated if the
     927             :  * subsequent checkpoint didn't write successfully.
     928             :  *
     929             :  * Therefore, CRC check the log from tail to head. If a failure occurs and the
     930             :  * offending record is within max iclog bufs from the head, walk the tail
     931             :  * forward and retry until a valid tail is found or corruption is detected out
     932             :  * of the range of a possible overwrite.
     933             :  */
     934             : STATIC int
     935       13735 : xlog_verify_tail(
     936             :         struct xlog             *log,
     937             :         xfs_daddr_t             head_blk,
     938             :         xfs_daddr_t             *tail_blk,
     939             :         int                     hsize)
     940             : {
     941       13735 :         struct xlog_rec_header  *thead;
     942       13735 :         char                    *buffer;
     943       13735 :         xfs_daddr_t             first_bad;
     944       13735 :         int                     error = 0;
     945       13735 :         bool                    wrapped;
     946       13735 :         xfs_daddr_t             tmp_tail;
     947       13735 :         xfs_daddr_t             orig_tail = *tail_blk;
     948             : 
     949       13735 :         buffer = xlog_alloc_buffer(log, 1);
     950       13735 :         if (!buffer)
     951             :                 return -ENOMEM;
     952             : 
     953             :         /*
     954             :          * Make sure the tail points to a record (returns positive count on
     955             :          * success).
     956             :          */
     957       13735 :         error = xlog_seek_logrec_hdr(log, head_blk, *tail_blk, 1, buffer,
     958             :                         &tmp_tail, &thead, &wrapped);
     959       13735 :         if (error < 0)
     960           0 :                 goto out;
     961       13735 :         if (*tail_blk != tmp_tail)
     962           0 :                 *tail_blk = tmp_tail;
     963             : 
     964             :         /*
     965             :          * Run a CRC check from the tail to the head. We can't just check
     966             :          * MAX_ICLOGS records past the tail because the tail may point to stale
     967             :          * blocks cleared during the search for the head/tail. These blocks are
     968             :          * overwritten with zero-length records and thus record count is not a
     969             :          * reliable indicator of the iclog state before a crash.
     970             :          */
     971       13735 :         first_bad = 0;
     972       13735 :         error = xlog_do_recovery_pass(log, head_blk, *tail_blk,
     973             :                                       XLOG_RECOVER_CRCPASS, &first_bad);
     974       13735 :         while ((error == -EFSBADCRC || error == -EFSCORRUPTED) && first_bad) {
     975           0 :                 int     tail_distance;
     976             : 
     977             :                 /*
     978             :                  * Is corruption within range of the head? If so, retry from
     979             :                  * the next record. Otherwise return an error.
     980             :                  */
     981           0 :                 tail_distance = xlog_tail_distance(log, head_blk, first_bad);
     982           0 :                 if (tail_distance > BTOBB(XLOG_MAX_ICLOGS * hsize))
     983             :                         break;
     984             : 
     985             :                 /* skip to the next record; returns positive count on success */
     986           0 :                 error = xlog_seek_logrec_hdr(log, head_blk, first_bad, 2,
     987             :                                 buffer, &tmp_tail, &thead, &wrapped);
     988           0 :                 if (error < 0)
     989           0 :                         goto out;
     990             : 
     991           0 :                 *tail_blk = tmp_tail;
     992           0 :                 first_bad = 0;
     993           0 :                 error = xlog_do_recovery_pass(log, head_blk, *tail_blk,
     994             :                                               XLOG_RECOVER_CRCPASS, &first_bad);
     995             :         }
     996             : 
     997       13735 :         if (!error && *tail_blk != orig_tail)
     998           0 :                 xfs_warn(log->l_mp,
     999             :                 "Tail block (0x%llx) overwrite detected. Updated to 0x%llx",
    1000             :                          orig_tail, *tail_blk);
    1001       13735 : out:
    1002       13735 :         kmem_free(buffer);
    1003       13735 :         return error;
    1004             : }
    1005             : 
    1006             : /*
    1007             :  * Detect and trim torn writes from the head of the log.
    1008             :  *
    1009             :  * Storage without sector atomicity guarantees can result in torn writes in the
    1010             :  * log in the event of a crash. Our only means to detect this scenario is via
    1011             :  * CRC verification. While we can't always be certain that CRC verification
    1012             :  * failure is due to a torn write vs. an unrelated corruption, we do know that
    1013             :  * only a certain number (XLOG_MAX_ICLOGS) of log records can be written out at
    1014             :  * one time. Therefore, CRC verify up to XLOG_MAX_ICLOGS records at the head of
    1015             :  * the log and treat failures in this range as torn writes as a matter of
    1016             :  * policy. In the event of CRC failure, the head is walked back to the last good
    1017             :  * record in the log and the tail is updated from that record and verified.
    1018             :  */
    1019             : STATIC int
    1020       13735 : xlog_verify_head(
    1021             :         struct xlog             *log,
    1022             :         xfs_daddr_t             *head_blk,      /* in/out: unverified head */
    1023             :         xfs_daddr_t             *tail_blk,      /* out: tail block */
    1024             :         char                    *buffer,
    1025             :         xfs_daddr_t             *rhead_blk,     /* start blk of last record */
    1026             :         struct xlog_rec_header  **rhead,        /* ptr to last record */
    1027             :         bool                    *wrapped)       /* last rec. wraps phys. log */
    1028             : {
    1029       13735 :         struct xlog_rec_header  *tmp_rhead;
    1030       13735 :         char                    *tmp_buffer;
    1031       13735 :         xfs_daddr_t             first_bad;
    1032       13735 :         xfs_daddr_t             tmp_rhead_blk;
    1033       13735 :         int                     found;
    1034       13735 :         int                     error;
    1035       13735 :         bool                    tmp_wrapped;
    1036             : 
    1037             :         /*
    1038             :          * Check the head of the log for torn writes. Search backwards from the
    1039             :          * head until we hit the tail or the maximum number of log record I/Os
    1040             :          * that could have been in flight at one time. Use a temporary buffer so
    1041             :          * we don't trash the rhead/buffer pointers from the caller.
    1042             :          */
    1043       13735 :         tmp_buffer = xlog_alloc_buffer(log, 1);
    1044       13735 :         if (!tmp_buffer)
    1045             :                 return -ENOMEM;
    1046       13735 :         error = xlog_rseek_logrec_hdr(log, *head_blk, *tail_blk,
    1047             :                                       XLOG_MAX_ICLOGS, tmp_buffer,
    1048             :                                       &tmp_rhead_blk, &tmp_rhead, &tmp_wrapped);
    1049       13735 :         kmem_free(tmp_buffer);
    1050       13735 :         if (error < 0)
    1051             :                 return error;
    1052             : 
    1053             :         /*
    1054             :          * Now run a CRC verification pass over the records starting at the
    1055             :          * block found above to the current head. If a CRC failure occurs, the
    1056             :          * log block of the first bad record is saved in first_bad.
    1057             :          */
    1058       13735 :         error = xlog_do_recovery_pass(log, *head_blk, tmp_rhead_blk,
    1059             :                                       XLOG_RECOVER_CRCPASS, &first_bad);
    1060       13735 :         if ((error == -EFSBADCRC || error == -EFSCORRUPTED) && first_bad) {
    1061             :                 /*
    1062             :                  * We've hit a potential torn write. Reset the error and warn
    1063             :                  * about it.
    1064             :                  */
    1065          56 :                 error = 0;
    1066          56 :                 xfs_warn(log->l_mp,
    1067             : "Torn write (CRC failure) detected at log block 0x%llx. Truncating head block from 0x%llx.",
    1068             :                          first_bad, *head_blk);
    1069             : 
    1070             :                 /*
    1071             :                  * Get the header block and buffer pointer for the last good
    1072             :                  * record before the bad record.
    1073             :                  *
    1074             :                  * Note that xlog_find_tail() clears the blocks at the new head
    1075             :                  * (i.e., the records with invalid CRC) if the cycle number
    1076             :                  * matches the current cycle.
    1077             :                  */
    1078          56 :                 found = xlog_rseek_logrec_hdr(log, first_bad, *tail_blk, 1,
    1079             :                                 buffer, rhead_blk, rhead, wrapped);
    1080          56 :                 if (found < 0)
    1081             :                         return found;
    1082          56 :                 if (found == 0)         /* XXX: right thing to do here? */
    1083             :                         return -EIO;
    1084             : 
    1085             :                 /*
    1086             :                  * Reset the head block to the starting block of the first bad
    1087             :                  * log record and set the tail block based on the last good
    1088             :                  * record.
    1089             :                  *
    1090             :                  * Bail out if the updated head/tail match as this indicates
    1091             :                  * possible corruption outside of the acceptable
    1092             :                  * (XLOG_MAX_ICLOGS) range. This is a job for xfs_repair...
    1093             :                  */
    1094          56 :                 *head_blk = first_bad;
    1095          56 :                 *tail_blk = BLOCK_LSN(be64_to_cpu((*rhead)->h_tail_lsn));
    1096          56 :                 if (*head_blk == *tail_blk) {
    1097           0 :                         ASSERT(0);
    1098           0 :                         return 0;
    1099             :                 }
    1100             :         }
    1101       13679 :         if (error)
    1102             :                 return error;
    1103             : 
    1104       13735 :         return xlog_verify_tail(log, *head_blk, tail_blk,
    1105       13735 :                                 be32_to_cpu((*rhead)->h_size));
    1106             : }
    1107             : 
    1108             : /*
    1109             :  * We need to make sure we handle log wrapping properly, so we can't use the
    1110             :  * calculated logbno directly. Make sure it wraps to the correct bno inside the
    1111             :  * log.
    1112             :  *
    1113             :  * The log is limited to 32 bit sizes, so we use the appropriate modulus
    1114             :  * operation here and cast it back to a 64 bit daddr on return.
    1115             :  */
    1116             : static inline xfs_daddr_t
    1117             : xlog_wrap_logbno(
    1118             :         struct xlog             *log,
    1119             :         xfs_daddr_t             bno)
    1120             : {
    1121      385713 :         int                     mod;
    1122             : 
    1123      385713 :         div_s64_rem(bno, log->l_logBBsize, &mod);
    1124      385713 :         return mod;
    1125             : }
    1126             : 
    1127             : /*
    1128             :  * Check whether the head of the log points to an unmount record. In other
    1129             :  * words, determine whether the log is clean. If so, update the in-core state
    1130             :  * appropriately.
    1131             :  */
    1132             : static int
    1133       59271 : xlog_check_unmount_rec(
    1134             :         struct xlog             *log,
    1135             :         xfs_daddr_t             *head_blk,
    1136             :         xfs_daddr_t             *tail_blk,
    1137             :         struct xlog_rec_header  *rhead,
    1138             :         xfs_daddr_t             rhead_blk,
    1139             :         char                    *buffer,
    1140             :         bool                    *clean)
    1141             : {
    1142       59271 :         struct xlog_op_header   *op_head;
    1143       59271 :         xfs_daddr_t             umount_data_blk;
    1144       59271 :         xfs_daddr_t             after_umount_blk;
    1145       59271 :         int                     hblks;
    1146       59271 :         int                     error;
    1147       59271 :         char                    *offset;
    1148             : 
    1149       59271 :         *clean = false;
    1150             : 
    1151             :         /*
    1152             :          * Look for unmount record. If we find it, then we know there was a
    1153             :          * clean unmount. Since 'i' could be the last block in the physical
    1154             :          * log, we convert to a log block before comparing to the head_blk.
    1155             :          *
    1156             :          * Save the current tail lsn to use to pass to xlog_clear_stale_blocks()
    1157             :          * below. We won't want to clear the unmount record if there is one, so
    1158             :          * we pass the lsn of the unmount record rather than the block after it.
    1159             :          */
    1160       59271 :         hblks = xlog_logrec_hblks(log, rhead);
    1161       59271 :         after_umount_blk = xlog_wrap_logbno(log,
    1162       59271 :                         rhead_blk + hblks + BTOBB(be32_to_cpu(rhead->h_len)));
    1163             : 
    1164       59271 :         if (*head_blk == after_umount_blk &&
    1165       59271 :             be32_to_cpu(rhead->h_num_logops) == 1) {
    1166       45486 :                 umount_data_blk = xlog_wrap_logbno(log, rhead_blk + hblks);
    1167       45486 :                 error = xlog_bread(log, umount_data_blk, 1, buffer, &offset);
    1168       45486 :                 if (error)
    1169             :                         return error;
    1170             : 
    1171       45486 :                 op_head = (struct xlog_op_header *)offset;
    1172       45486 :                 if (op_head->oh_flags & XLOG_UNMOUNT_TRANS) {
    1173             :                         /*
    1174             :                          * Set tail and last sync so that newly written log
    1175             :                          * records will point recovery to after the current
    1176             :                          * unmount record.
    1177             :                          */
    1178       45481 :                         xlog_assign_atomic_lsn(&log->l_tail_lsn,
    1179       45481 :                                         log->l_curr_cycle, after_umount_blk);
    1180       45481 :                         xlog_assign_atomic_lsn(&log->l_last_sync_lsn,
    1181             :                                         log->l_curr_cycle, after_umount_blk);
    1182       45481 :                         *tail_blk = after_umount_blk;
    1183             : 
    1184       45481 :                         *clean = true;
    1185             :                 }
    1186             :         }
    1187             : 
    1188             :         return 0;
    1189             : }
    1190             : 
    1191             : static void
    1192       59271 : xlog_set_state(
    1193             :         struct xlog             *log,
    1194             :         xfs_daddr_t             head_blk,
    1195             :         struct xlog_rec_header  *rhead,
    1196             :         xfs_daddr_t             rhead_blk,
    1197             :         bool                    bump_cycle)
    1198             : {
    1199             :         /*
    1200             :          * Reset log values according to the state of the log when we
    1201             :          * crashed.  In the case where head_blk == 0, we bump curr_cycle
    1202             :          * one because the next write starts a new cycle rather than
    1203             :          * continuing the cycle of the last good log record.  At this
    1204             :          * point we have guaranteed that all partial log records have been
    1205             :          * accounted for.  Therefore, we know that the last good log record
    1206             :          * written was complete and ended exactly on the end boundary
    1207             :          * of the physical log.
    1208             :          */
    1209       59271 :         log->l_prev_block = rhead_blk;
    1210       59271 :         log->l_curr_block = (int)head_blk;
    1211       59271 :         log->l_curr_cycle = be32_to_cpu(rhead->h_cycle);
    1212       59271 :         if (bump_cycle)
    1213         140 :                 log->l_curr_cycle++;
    1214       59271 :         atomic64_set(&log->l_tail_lsn, be64_to_cpu(rhead->h_tail_lsn));
    1215       59271 :         atomic64_set(&log->l_last_sync_lsn, be64_to_cpu(rhead->h_lsn));
    1216       59271 :         xlog_assign_grant_head(&log->l_reserve_head.grant, log->l_curr_cycle,
    1217             :                                         BBTOB(log->l_curr_block));
    1218       59271 :         xlog_assign_grant_head(&log->l_write_head.grant, log->l_curr_cycle,
    1219             :                                         BBTOB(log->l_curr_block));
    1220       59271 : }
    1221             : 
    1222             : /*
    1223             :  * Find the sync block number or the tail of the log.
    1224             :  *
    1225             :  * This will be the block number of the last record to have its
    1226             :  * associated buffers synced to disk.  Every log record header has
    1227             :  * a sync lsn embedded in it.  LSNs hold block numbers, so it is easy
    1228             :  * to get a sync block number.  The only concern is to figure out which
    1229             :  * log record header to believe.
    1230             :  *
    1231             :  * The following algorithm uses the log record header with the largest
    1232             :  * lsn.  The entire log record does not need to be valid.  We only care
    1233             :  * that the header is valid.
    1234             :  *
    1235             :  * We could speed up search by using current head_blk buffer, but it is not
    1236             :  * available.
    1237             :  */
    1238             : STATIC int
    1239       59235 : xlog_find_tail(
    1240             :         struct xlog             *log,
    1241             :         xfs_daddr_t             *head_blk,
    1242             :         xfs_daddr_t             *tail_blk)
    1243             : {
    1244       59235 :         xlog_rec_header_t       *rhead;
    1245       59235 :         char                    *offset = NULL;
    1246       59235 :         char                    *buffer;
    1247       59235 :         int                     error;
    1248       59235 :         xfs_daddr_t             rhead_blk;
    1249       59235 :         xfs_lsn_t               tail_lsn;
    1250       59235 :         bool                    wrapped = false;
    1251       59235 :         bool                    clean = false;
    1252             : 
    1253             :         /*
    1254             :          * Find previous log record
    1255             :          */
    1256       59235 :         if ((error = xlog_find_head(log, head_blk)))
    1257             :                 return error;
    1258       59215 :         ASSERT(*head_blk < INT_MAX);
    1259             : 
    1260       59215 :         buffer = xlog_alloc_buffer(log, 1);
    1261       59215 :         if (!buffer)
    1262             :                 return -ENOMEM;
    1263       59215 :         if (*head_blk == 0) {                           /* special case */
    1264         137 :                 error = xlog_bread(log, 0, 1, buffer, &offset);
    1265         137 :                 if (error)
    1266           0 :                         goto done;
    1267             : 
    1268         274 :                 if (xlog_get_cycle(offset) == 0) {
    1269           0 :                         *tail_blk = 0;
    1270             :                         /* leave all other log inited values alone */
    1271           0 :                         goto done;
    1272             :                 }
    1273             :         }
    1274             : 
    1275             :         /*
    1276             :          * Search backwards through the log looking for the log record header
    1277             :          * block. This wraps all the way back around to the head so something is
    1278             :          * seriously wrong if we can't find it.
    1279             :          */
    1280       59215 :         error = xlog_rseek_logrec_hdr(log, *head_blk, *head_blk, 1, buffer,
    1281             :                                       &rhead_blk, &rhead, &wrapped);
    1282       59215 :         if (error < 0)
    1283           0 :                 goto done;
    1284       59215 :         if (!error) {
    1285           0 :                 xfs_warn(log->l_mp, "%s: couldn't find sync record", __func__);
    1286           0 :                 error = -EFSCORRUPTED;
    1287           0 :                 goto done;
    1288             :         }
    1289       59215 :         *tail_blk = BLOCK_LSN(be64_to_cpu(rhead->h_tail_lsn));
    1290             : 
    1291             :         /*
    1292             :          * Set the log state based on the current head record.
    1293             :          */
    1294       59215 :         xlog_set_state(log, *head_blk, rhead, rhead_blk, wrapped);
    1295       59215 :         tail_lsn = atomic64_read(&log->l_tail_lsn);
    1296             : 
    1297             :         /*
    1298             :          * Look for an unmount record at the head of the log. This sets the log
    1299             :          * state to determine whether recovery is necessary.
    1300             :          */
    1301       59215 :         error = xlog_check_unmount_rec(log, head_blk, tail_blk, rhead,
    1302             :                                        rhead_blk, buffer, &clean);
    1303       59215 :         if (error)
    1304           0 :                 goto done;
    1305             : 
    1306             :         /*
    1307             :          * Verify the log head if the log is not clean (e.g., we have anything
    1308             :          * but an unmount record at the head). This uses CRC verification to
    1309             :          * detect and trim torn writes. If discovered, CRC failures are
    1310             :          * considered torn writes and the log head is trimmed accordingly.
    1311             :          *
    1312             :          * Note that we can only run CRC verification when the log is dirty
    1313             :          * because there's no guarantee that the log data behind an unmount
    1314             :          * record is compatible with the current architecture.
    1315             :          */
    1316       59215 :         if (!clean) {
    1317       13735 :                 xfs_daddr_t     orig_head = *head_blk;
    1318             : 
    1319       13735 :                 error = xlog_verify_head(log, head_blk, tail_blk, buffer,
    1320             :                                          &rhead_blk, &rhead, &wrapped);
    1321       13735 :                 if (error)
    1322           0 :                         goto done;
    1323             : 
    1324             :                 /* update in-core state again if the head changed */
    1325       13735 :                 if (*head_blk != orig_head) {
    1326          56 :                         xlog_set_state(log, *head_blk, rhead, rhead_blk,
    1327             :                                        wrapped);
    1328          56 :                         tail_lsn = atomic64_read(&log->l_tail_lsn);
    1329          56 :                         error = xlog_check_unmount_rec(log, head_blk, tail_blk,
    1330             :                                                        rhead, rhead_blk, buffer,
    1331             :                                                        &clean);
    1332          56 :                         if (error)
    1333           0 :                                 goto done;
    1334             :                 }
    1335             :         }
    1336             : 
    1337             :         /*
    1338             :          * Note that the unmount was clean. If the unmount was not clean, we
    1339             :          * need to know this to rebuild the superblock counters from the perag
    1340             :          * headers if we have a filesystem using non-persistent counters.
    1341             :          */
    1342       59215 :         if (clean)
    1343       45481 :                 set_bit(XFS_OPSTATE_CLEAN, &log->l_mp->m_opstate);
    1344             : 
    1345             :         /*
    1346             :          * Make sure that there are no blocks in front of the head
    1347             :          * with the same cycle number as the head.  This can happen
    1348             :          * because we allow multiple outstanding log writes concurrently,
    1349             :          * and the later writes might make it out before earlier ones.
    1350             :          *
    1351             :          * We use the lsn from before modifying it so that we'll never
    1352             :          * overwrite the unmount record after a clean unmount.
    1353             :          *
    1354             :          * Do this only if we are going to recover the filesystem
    1355             :          *
    1356             :          * NOTE: This used to say "if (!readonly)"
    1357             :          * However on Linux, we can & do recover a read-only filesystem.
    1358             :          * We only skip recovery if NORECOVERY is specified on mount,
    1359             :          * in which case we would not be here.
    1360             :          *
    1361             :          * But... if the -device- itself is readonly, just skip this.
    1362             :          * We can't recover this device anyway, so it won't matter.
    1363             :          */
    1364       59215 :         if (!xfs_readonly_buftarg(log->l_targ))
    1365       59203 :                 error = xlog_clear_stale_blocks(log, tail_lsn);
    1366             : 
    1367          12 : done:
    1368       59215 :         kmem_free(buffer);
    1369             : 
    1370       59215 :         if (error)
    1371           0 :                 xfs_warn(log->l_mp, "failed to locate log tail");
    1372             :         return error;
    1373             : }
    1374             : 
    1375             : /*
    1376             :  * Is the log zeroed at all?
    1377             :  *
    1378             :  * The last binary search should be changed to perform an X block read
    1379             :  * once X becomes small enough.  You can then search linearly through
    1380             :  * the X blocks.  This will cut down on the number of reads we need to do.
    1381             :  *
    1382             :  * If the log is partially zeroed, this routine will pass back the blkno
    1383             :  * of the first block with cycle number 0.  It won't have a complete LR
    1384             :  * preceding it.
    1385             :  *
    1386             :  * Return:
    1387             :  *      0  => the log is completely written to
    1388             :  *      1 => use *blk_no as the first block of the log
    1389             :  *      <0 => error has occurred
    1390             :  */
    1391             : STATIC int
    1392       59235 : xlog_find_zeroed(
    1393             :         struct xlog     *log,
    1394             :         xfs_daddr_t     *blk_no)
    1395             : {
    1396       59235 :         char            *buffer;
    1397       59235 :         char            *offset;
    1398       59235 :         uint            first_cycle, last_cycle;
    1399       59235 :         xfs_daddr_t     new_blk, last_blk, start_blk;
    1400       59235 :         xfs_daddr_t     num_scan_bblks;
    1401       59235 :         int             error, log_bbnum = log->l_logBBsize;
    1402             : 
    1403       59235 :         *blk_no = 0;
    1404             : 
    1405             :         /* check totally zeroed log */
    1406       59235 :         buffer = xlog_alloc_buffer(log, 1);
    1407       59235 :         if (!buffer)
    1408             :                 return -ENOMEM;
    1409       59235 :         error = xlog_bread(log, 0, 1, buffer, &offset);
    1410       59235 :         if (error)
    1411           0 :                 goto out_free_buffer;
    1412             : 
    1413       59235 :         first_cycle = xlog_get_cycle(offset);
    1414       59235 :         if (first_cycle == 0) {         /* completely zeroed log */
    1415           0 :                 *blk_no = 0;
    1416           0 :                 kmem_free(buffer);
    1417           0 :                 return 1;
    1418             :         }
    1419             : 
    1420             :         /* check partially zeroed log */
    1421       59235 :         error = xlog_bread(log, log_bbnum-1, 1, buffer, &offset);
    1422       59235 :         if (error)
    1423           0 :                 goto out_free_buffer;
    1424             : 
    1425       59235 :         last_cycle = xlog_get_cycle(offset);
    1426       59235 :         if (last_cycle != 0) {          /* log completely written to */
    1427       22525 :                 kmem_free(buffer);
    1428       22525 :                 return 0;
    1429             :         }
    1430             : 
    1431             :         /* we have a partially zeroed log */
    1432       36710 :         last_blk = log_bbnum-1;
    1433       36710 :         error = xlog_find_cycle_start(log, buffer, 0, &last_blk, 0);
    1434       36710 :         if (error)
    1435           0 :                 goto out_free_buffer;
    1436             : 
    1437             :         /*
    1438             :          * Validate the answer.  Because there is no way to guarantee that
    1439             :          * the entire log is made up of log records which are the same size,
    1440             :          * we scan over the defined maximum blocks.  At this point, the maximum
    1441             :          * is not chosen to mean anything special.   XXXmiken
    1442             :          */
    1443       36710 :         num_scan_bblks = XLOG_TOTAL_REC_SHIFT(log);
    1444       36710 :         ASSERT(num_scan_bblks <= INT_MAX);
    1445             : 
    1446       36710 :         if (last_blk < num_scan_bblks)
    1447             :                 num_scan_bblks = last_blk;
    1448       36710 :         start_blk = last_blk - num_scan_bblks;
    1449             : 
    1450             :         /*
    1451             :          * We search for any instances of cycle number 0 that occur before
    1452             :          * our current estimate of the head.  What we're trying to detect is
    1453             :          *        1 ... | 0 | 1 | 0...
    1454             :          *                       ^ binary search ends here
    1455             :          */
    1456       36710 :         if ((error = xlog_find_verify_cycle(log, start_blk,
    1457             :                                          (int)num_scan_bblks, 0, &new_blk)))
    1458           0 :                 goto out_free_buffer;
    1459       36710 :         if (new_blk != -1)
    1460           0 :                 last_blk = new_blk;
    1461             : 
    1462             :         /*
    1463             :          * Potentially backup over partial log record write.  We don't need
    1464             :          * to search the end of the log because we know it is zero.
    1465             :          */
    1466       36710 :         error = xlog_find_verify_log_record(log, start_blk, &last_blk, 0);
    1467       36710 :         if (error == 1)
    1468             :                 error = -EIO;
    1469       36710 :         if (error)
    1470           0 :                 goto out_free_buffer;
    1471             : 
    1472       36710 :         *blk_no = last_blk;
    1473       36710 : out_free_buffer:
    1474       36710 :         kmem_free(buffer);
    1475       36710 :         if (error)
    1476           0 :                 return error;
    1477             :         return 1;
    1478             : }
    1479             : 
    1480             : /*
    1481             :  * These are simple subroutines used by xlog_clear_stale_blocks() below
    1482             :  * to initialize a buffer full of empty log record headers and write
    1483             :  * them into the log.
    1484             :  */
    1485             : STATIC void
    1486   242384832 : xlog_add_record(
    1487             :         struct xlog             *log,
    1488             :         char                    *buf,
    1489             :         int                     cycle,
    1490             :         int                     block,
    1491             :         int                     tail_cycle,
    1492             :         int                     tail_block)
    1493             : {
    1494   242384832 :         xlog_rec_header_t       *recp = (xlog_rec_header_t *)buf;
    1495             : 
    1496   242384832 :         memset(buf, 0, BBSIZE);
    1497   242384832 :         recp->h_magicno = cpu_to_be32(XLOG_HEADER_MAGIC_NUM);
    1498   242384832 :         recp->h_cycle = cpu_to_be32(cycle);
    1499   242384832 :         recp->h_version = cpu_to_be32(
    1500             :                         xfs_has_logv2(log->l_mp) ? 2 : 1);
    1501   242384832 :         recp->h_lsn = cpu_to_be64(xlog_assign_lsn(cycle, block));
    1502   242384832 :         recp->h_tail_lsn = cpu_to_be64(xlog_assign_lsn(tail_cycle, tail_block));
    1503   242384832 :         recp->h_fmt = cpu_to_be32(XLOG_FMT);
    1504   484769664 :         memcpy(&recp->h_fs_uuid, &log->l_mp->m_sb.sb_uuid, sizeof(uuid_t));
    1505   242384832 : }
    1506             : 
    1507             : STATIC int
    1508       60076 : xlog_write_log_records(
    1509             :         struct xlog     *log,
    1510             :         int             cycle,
    1511             :         int             start_block,
    1512             :         int             blocks,
    1513             :         int             tail_cycle,
    1514             :         int             tail_block)
    1515             : {
    1516       60076 :         char            *offset;
    1517       60076 :         char            *buffer;
    1518       60076 :         int             balign, ealign;
    1519       60076 :         int             sectbb = log->l_sectBBsize;
    1520       60076 :         int             end_block = start_block + blocks;
    1521       60076 :         int             bufblks;
    1522       60076 :         int             error = 0;
    1523       60076 :         int             i, j = 0;
    1524             : 
    1525             :         /*
    1526             :          * Greedily allocate a buffer big enough to handle the full
    1527             :          * range of basic blocks to be written.  If that fails, try
    1528             :          * a smaller size.  We need to be able to write at least a
    1529             :          * log sector, or we're out of luck.
    1530             :          */
    1531      120152 :         bufblks = 1 << ffs(blocks);
    1532       60111 :         while (bufblks > log->l_logBBsize)
    1533          35 :                 bufblks >>= 1;
    1534       60076 :         while (!(buffer = xlog_alloc_buffer(log, bufblks))) {
    1535           0 :                 bufblks >>= 1;
    1536           0 :                 if (bufblks < sectbb)
    1537             :                         return -ENOMEM;
    1538             :         }
    1539             : 
    1540             :         /* We may need to do a read at the start to fill in part of
    1541             :          * the buffer in the starting sector not covered by the first
    1542             :          * write below.
    1543             :          */
    1544       60076 :         balign = round_down(start_block, sectbb);
    1545       60076 :         if (balign != start_block) {
    1546           0 :                 error = xlog_bread_noalign(log, start_block, 1, buffer);
    1547           0 :                 if (error)
    1548           0 :                         goto out_free_buffer;
    1549             : 
    1550           0 :                 j = start_block - balign;
    1551             :         }
    1552             : 
    1553      550490 :         for (i = start_block; i < end_block; i += bufblks) {
    1554      490414 :                 int             bcount, endcount;
    1555             : 
    1556      490414 :                 bcount = min(bufblks, end_block - start_block);
    1557      490414 :                 endcount = bcount - j;
    1558             : 
    1559             :                 /* We may need to do a read at the end to fill in part of
    1560             :                  * the buffer in the final sector not covered by the write.
    1561             :                  * If this is the same sector as the above read, skip it.
    1562             :                  */
    1563      490414 :                 ealign = round_down(end_block, sectbb);
    1564      490414 :                 if (j == 0 && (start_block + endcount > ealign)) {
    1565           0 :                         error = xlog_bread_noalign(log, ealign, sectbb,
    1566           0 :                                         buffer + BBTOB(ealign - start_block));
    1567           0 :                         if (error)
    1568             :                                 break;
    1569             : 
    1570             :                 }
    1571             : 
    1572      490414 :                 offset = buffer + xlog_align(log, start_block);
    1573   242875246 :                 for (; j < endcount; j++) {
    1574   242384832 :                         xlog_add_record(log, offset, cycle, i+j,
    1575             :                                         tail_cycle, tail_block);
    1576   242384832 :                         offset += BBSIZE;
    1577             :                 }
    1578      490414 :                 error = xlog_bwrite(log, start_block, endcount, buffer);
    1579      490414 :                 if (error)
    1580             :                         break;
    1581      490414 :                 start_block += endcount;
    1582      490414 :                 j = 0;
    1583             :         }
    1584             : 
    1585       60076 : out_free_buffer:
    1586       60076 :         kmem_free(buffer);
    1587       60076 :         return error;
    1588             : }
    1589             : 
    1590             : /*
    1591             :  * This routine is called to blow away any incomplete log writes out
    1592             :  * in front of the log head.  We do this so that we won't become confused
    1593             :  * if we come up, write only a little bit more, and then crash again.
    1594             :  * If we leave the partial log records out there, this situation could
    1595             :  * cause us to think those partial writes are valid blocks since they
    1596             :  * have the current cycle number.  We get rid of them by overwriting them
    1597             :  * with empty log records with the old cycle number rather than the
    1598             :  * current one.
    1599             :  *
    1600             :  * The tail lsn is passed in rather than taken from
    1601             :  * the log so that we will not write over the unmount record after a
    1602             :  * clean unmount in a 512 block log.  Doing so would leave the log without
    1603             :  * any valid log records in it until a new one was written.  If we crashed
    1604             :  * during that time we would not be able to recover.
    1605             :  */
    1606             : STATIC int
    1607       59203 : xlog_clear_stale_blocks(
    1608             :         struct xlog     *log,
    1609             :         xfs_lsn_t       tail_lsn)
    1610             : {
    1611       59203 :         int             tail_cycle, head_cycle;
    1612       59203 :         int             tail_block, head_block;
    1613       59203 :         int             tail_distance, max_distance;
    1614       59203 :         int             distance;
    1615       59203 :         int             error;
    1616             : 
    1617       59203 :         tail_cycle = CYCLE_LSN(tail_lsn);
    1618       59203 :         tail_block = BLOCK_LSN(tail_lsn);
    1619       59203 :         head_cycle = log->l_curr_cycle;
    1620       59203 :         head_block = log->l_curr_block;
    1621             : 
    1622             :         /*
    1623             :          * Figure out the distance between the new head of the log
    1624             :          * and the tail.  We want to write over any blocks beyond the
    1625             :          * head that we may have written just before the crash, but
    1626             :          * we don't want to overwrite the tail of the log.
    1627             :          */
    1628       59203 :         if (head_cycle == tail_cycle) {
    1629             :                 /*
    1630             :                  * The tail is behind the head in the physical log,
    1631             :                  * so the distance from the head to the tail is the
    1632             :                  * distance from the head to the end of the log plus
    1633             :                  * the distance from the beginning of the log to the
    1634             :                  * tail.
    1635             :                  */
    1636       58420 :                 if (XFS_IS_CORRUPT(log->l_mp,
    1637             :                                    head_block < tail_block ||
    1638             :                                    head_block >= log->l_logBBsize))
    1639           0 :                         return -EFSCORRUPTED;
    1640       58420 :                 tail_distance = tail_block + (log->l_logBBsize - head_block);
    1641             :         } else {
    1642             :                 /*
    1643             :                  * The head is behind the tail in the physical log,
    1644             :                  * so the distance from the head to the tail is just
    1645             :                  * the tail block minus the head block.
    1646             :                  */
    1647         783 :                 if (XFS_IS_CORRUPT(log->l_mp,
    1648             :                                    head_block >= tail_block ||
    1649             :                                    head_cycle != tail_cycle + 1))
    1650           0 :                         return -EFSCORRUPTED;
    1651         783 :                 tail_distance = tail_block - head_block;
    1652             :         }
    1653             : 
    1654             :         /*
    1655             :          * If the head is right up against the tail, we can't clear
    1656             :          * anything.
    1657             :          */
    1658       59203 :         if (tail_distance <= 0) {
    1659           0 :                 ASSERT(tail_distance == 0);
    1660           0 :                 return 0;
    1661             :         }
    1662             : 
    1663       59203 :         max_distance = XLOG_TOTAL_REC_SHIFT(log);
    1664             :         /*
    1665             :          * Take the smaller of the maximum amount of outstanding I/O
    1666             :          * we could have and the distance to the tail to clear out.
    1667             :          * We take the smaller so that we don't overwrite the tail and
    1668             :          * we don't waste all day writing from the head to the tail
    1669             :          * for no reason.
    1670             :          */
    1671       59203 :         max_distance = min(max_distance, tail_distance);
    1672             : 
    1673       59203 :         if ((head_block + max_distance) <= log->l_logBBsize) {
    1674             :                 /*
    1675             :                  * We can stomp all the blocks we need to without
    1676             :                  * wrapping around the end of the log.  Just do it
    1677             :                  * in a single write.  Use the cycle number of the
    1678             :                  * current cycle minus one so that the log will look like:
    1679             :                  *     n ... | n - 1 ...
    1680             :                  */
    1681       58330 :                 error = xlog_write_log_records(log, (head_cycle - 1),
    1682             :                                 head_block, max_distance, tail_cycle,
    1683             :                                 tail_block);
    1684       58330 :                 if (error)
    1685           0 :                         return error;
    1686             :         } else {
    1687             :                 /*
    1688             :                  * We need to wrap around the end of the physical log in
    1689             :                  * order to clear all the blocks.  Do it in two separate
    1690             :                  * I/Os.  The first write should be from the head to the
    1691             :                  * end of the physical log, and it should use the current
    1692             :                  * cycle number minus one just like above.
    1693             :                  */
    1694         873 :                 distance = log->l_logBBsize - head_block;
    1695         873 :                 error = xlog_write_log_records(log, (head_cycle - 1),
    1696             :                                 head_block, distance, tail_cycle,
    1697             :                                 tail_block);
    1698             : 
    1699         873 :                 if (error)
    1700             :                         return error;
    1701             : 
    1702             :                 /*
    1703             :                  * Now write the blocks at the start of the physical log.
    1704             :                  * This writes the remainder of the blocks we want to clear.
    1705             :                  * It uses the current cycle number since we're now on the
    1706             :                  * same cycle as the head so that we get:
    1707             :                  *    n ... n ... | n - 1 ...
    1708             :                  *    ^^^^^ blocks we're writing
    1709             :                  */
    1710         873 :                 distance = max_distance - (log->l_logBBsize - head_block);
    1711         873 :                 error = xlog_write_log_records(log, head_cycle, 0, distance,
    1712             :                                 tail_cycle, tail_block);
    1713         873 :                 if (error)
    1714           0 :                         return error;
    1715             :         }
    1716             : 
    1717             :         return 0;
    1718             : }
    1719             : 
    1720             : /*
    1721             :  * Release the recovered intent item in the AIL that matches the given intent
    1722             :  * type and intent id.
    1723             :  */
    1724             : void
    1725      150951 : xlog_recover_release_intent(
    1726             :         struct xlog             *log,
    1727             :         unsigned short          intent_type,
    1728             :         uint64_t                intent_id)
    1729             : {
    1730      150951 :         struct xfs_ail_cursor   cur;
    1731      150951 :         struct xfs_log_item     *lip;
    1732      150951 :         struct xfs_ail          *ailp = log->l_ailp;
    1733             : 
    1734      150951 :         spin_lock(&ailp->ail_lock);
    1735      180775 :         for (lip = xfs_trans_ail_cursor_first(ailp, &cur, 0); lip != NULL;
    1736       29824 :              lip = xfs_trans_ail_cursor_next(ailp, &cur)) {
    1737      180119 :                 if (lip->li_type != intent_type)
    1738       22378 :                         continue;
    1739      157741 :                 if (!lip->li_ops->iop_match(lip, intent_id))
    1740        7446 :                         continue;
    1741             : 
    1742      150295 :                 spin_unlock(&ailp->ail_lock);
    1743      150295 :                 lip->li_ops->iop_release(lip);
    1744      150295 :                 spin_lock(&ailp->ail_lock);
    1745             :                 break;
    1746             :         }
    1747             : 
    1748      150951 :         xfs_trans_ail_cursor_done(&cur);
    1749      150951 :         spin_unlock(&ailp->ail_lock);
    1750      150951 : }
    1751             : 
    1752             : int
    1753         732 : xlog_recover_iget(
    1754             :         struct xfs_mount        *mp,
    1755             :         xfs_ino_t               ino,
    1756             :         struct xfs_inode        **ipp)
    1757             : {
    1758         732 :         int                     error;
    1759             : 
    1760         732 :         error = xfs_iget(mp, NULL, ino, 0, 0, ipp);
    1761         732 :         if (error)
    1762             :                 return error;
    1763             : 
    1764         732 :         error = xfs_qm_dqattach(*ipp);
    1765         732 :         if (error) {
    1766           0 :                 xfs_irele(*ipp);
    1767           0 :                 return error;
    1768             :         }
    1769             : 
    1770         732 :         if (VFS_I(*ipp)->i_nlink == 0)
    1771          30 :                 xfs_iflags_set(*ipp, XFS_IRECOVERY);
    1772             : 
    1773             :         return 0;
    1774             : }
    1775             : 
    1776             : /******************************************************************************
    1777             :  *
    1778             :  *              Log recover routines
    1779             :  *
    1780             :  ******************************************************************************
    1781             :  */
    1782             : static const struct xlog_recover_item_ops *xlog_recover_item_ops[] = {
    1783             :         &xlog_buf_item_ops,
    1784             :         &xlog_inode_item_ops,
    1785             :         &xlog_dquot_item_ops,
    1786             :         &xlog_quotaoff_item_ops,
    1787             :         &xlog_icreate_item_ops,
    1788             :         &xlog_efi_item_ops,
    1789             :         &xlog_efd_item_ops,
    1790             :         &xlog_rui_item_ops,
    1791             :         &xlog_rud_item_ops,
    1792             :         &xlog_cui_item_ops,
    1793             :         &xlog_cud_item_ops,
    1794             :         &xlog_bui_item_ops,
    1795             :         &xlog_bud_item_ops,
    1796             :         &xlog_attri_item_ops,
    1797             :         &xlog_attrd_item_ops,
    1798             : };
    1799             : 
    1800             : static const struct xlog_recover_item_ops *
    1801    65203640 : xlog_find_item_ops(
    1802             :         struct xlog_recover_item                *item)
    1803             : {
    1804    65203640 :         unsigned int                            i;
    1805             : 
    1806   115624724 :         for (i = 0; i < ARRAY_SIZE(xlog_recover_item_ops); i++)
    1807   115624724 :                 if (ITEM_TYPE(item) == xlog_recover_item_ops[i]->item_type)
    1808    65203640 :                         return xlog_recover_item_ops[i];
    1809             : 
    1810             :         return NULL;
    1811             : }
    1812             : 
    1813             : /*
    1814             :  * Sort the log items in the transaction.
    1815             :  *
    1816             :  * The ordering constraints are defined by the inode allocation and unlink
    1817             :  * behaviour. The rules are:
    1818             :  *
    1819             :  *      1. Every item is only logged once in a given transaction. Hence it
    1820             :  *         represents the last logged state of the item. Hence ordering is
    1821             :  *         dependent on the order in which operations need to be performed so
    1822             :  *         required initial conditions are always met.
    1823             :  *
    1824             :  *      2. Cancelled buffers are recorded in pass 1 in a separate table and
    1825             :  *         there's nothing to replay from them so we can simply cull them
    1826             :  *         from the transaction. However, we can't do that until after we've
    1827             :  *         replayed all the other items because they may be dependent on the
    1828             :  *         cancelled buffer and replaying the cancelled buffer can remove it
    1829             :  *         form the cancelled buffer table. Hence they have tobe done last.
    1830             :  *
    1831             :  *      3. Inode allocation buffers must be replayed before inode items that
    1832             :  *         read the buffer and replay changes into it. For filesystems using the
    1833             :  *         ICREATE transactions, this means XFS_LI_ICREATE objects need to get
    1834             :  *         treated the same as inode allocation buffers as they create and
    1835             :  *         initialise the buffers directly.
    1836             :  *
    1837             :  *      4. Inode unlink buffers must be replayed after inode items are replayed.
    1838             :  *         This ensures that inodes are completely flushed to the inode buffer
    1839             :  *         in a "free" state before we remove the unlinked inode list pointer.
    1840             :  *
    1841             :  * Hence the ordering needs to be inode allocation buffers first, inode items
    1842             :  * second, inode unlink buffers third and cancelled buffers last.
    1843             :  *
    1844             :  * But there's a problem with that - we can't tell an inode allocation buffer
    1845             :  * apart from a regular buffer, so we can't separate them. We can, however,
    1846             :  * tell an inode unlink buffer from the others, and so we can separate them out
    1847             :  * from all the other buffers and move them to last.
    1848             :  *
    1849             :  * Hence, 4 lists, in order from head to tail:
    1850             :  *      - buffer_list for all buffers except cancelled/inode unlink buffers
    1851             :  *      - item_list for all non-buffer items
    1852             :  *      - inode_buffer_list for inode unlink buffers
    1853             :  *      - cancel_list for the cancelled buffers
    1854             :  *
    1855             :  * Note that we add objects to the tail of the lists so that first-to-last
    1856             :  * ordering is preserved within the lists. Adding objects to the head of the
    1857             :  * list means when we traverse from the head we walk them in last-to-first
    1858             :  * order. For cancelled buffers and inode unlink buffers this doesn't matter,
    1859             :  * but for all other items there may be specific ordering that we need to
    1860             :  * preserve.
    1861             :  */
    1862             : STATIC int
    1863      904380 : xlog_recover_reorder_trans(
    1864             :         struct xlog             *log,
    1865             :         struct xlog_recover     *trans,
    1866             :         int                     pass)
    1867             : {
    1868      904380 :         struct xlog_recover_item *item, *n;
    1869      904380 :         int                     error = 0;
    1870      904380 :         LIST_HEAD(sort_list);
    1871      904380 :         LIST_HEAD(cancel_list);
    1872      904380 :         LIST_HEAD(buffer_list);
    1873      904380 :         LIST_HEAD(inode_buffer_list);
    1874      904380 :         LIST_HEAD(item_list);
    1875             : 
    1876      904380 :         list_splice_init(&trans->r_itemq, &sort_list);
    1877    66108020 :         list_for_each_entry_safe(item, n, &sort_list, ri_list) {
    1878    65203640 :                 enum xlog_recover_reorder       fate = XLOG_REORDER_ITEM_LIST;
    1879             : 
    1880    65203640 :                 item->ri_ops = xlog_find_item_ops(item);
    1881    65203640 :                 if (!item->ri_ops) {
    1882           0 :                         xfs_warn(log->l_mp,
    1883             :                                 "%s: unrecognized type of log operation (%d)",
    1884             :                                 __func__, ITEM_TYPE(item));
    1885           0 :                         ASSERT(0);
    1886             :                         /*
    1887             :                          * return the remaining items back to the transaction
    1888             :                          * item list so they can be freed in caller.
    1889             :                          */
    1890           0 :                         if (!list_empty(&sort_list))
    1891           0 :                                 list_splice_init(&sort_list, &trans->r_itemq);
    1892             :                         error = -EFSCORRUPTED;
    1893             :                         break;
    1894             :                 }
    1895             : 
    1896    65203640 :                 if (item->ri_ops->reorder)
    1897    33154902 :                         fate = item->ri_ops->reorder(item);
    1898             : 
    1899    33154902 :                 switch (fate) {
    1900    32490146 :                 case XLOG_REORDER_BUFFER_LIST:
    1901    32490146 :                         list_move_tail(&item->ri_list, &buffer_list);
    1902    32490146 :                         break;
    1903      598062 :                 case XLOG_REORDER_CANCEL_LIST:
    1904      598062 :                         trace_xfs_log_recover_item_reorder_head(log,
    1905             :                                         trans, item, pass);
    1906      598062 :                         list_move(&item->ri_list, &cancel_list);
    1907      598062 :                         break;
    1908       66694 :                 case XLOG_REORDER_INODE_BUFFER_LIST:
    1909       66694 :                         list_move(&item->ri_list, &inode_buffer_list);
    1910       66694 :                         break;
    1911    32048738 :                 case XLOG_REORDER_ITEM_LIST:
    1912    32048738 :                         trace_xfs_log_recover_item_reorder_tail(log,
    1913             :                                                         trans, item, pass);
    1914    32048738 :                         list_move_tail(&item->ri_list, &item_list);
    1915    32048738 :                         break;
    1916             :                 }
    1917             :         }
    1918             : 
    1919      904380 :         ASSERT(list_empty(&sort_list));
    1920      904380 :         if (!list_empty(&buffer_list))
    1921      865410 :                 list_splice(&buffer_list, &trans->r_itemq);
    1922      904380 :         if (!list_empty(&item_list))
    1923      901362 :                 list_splice_tail(&item_list, &trans->r_itemq);
    1924      904380 :         if (!list_empty(&inode_buffer_list))
    1925        4858 :                 list_splice_tail(&inode_buffer_list, &trans->r_itemq);
    1926      904380 :         if (!list_empty(&cancel_list))
    1927      109340 :                 list_splice_tail(&cancel_list, &trans->r_itemq);
    1928      904380 :         return error;
    1929             : }
    1930             : 
    1931             : void
    1932    32266373 : xlog_buf_readahead(
    1933             :         struct xlog             *log,
    1934             :         xfs_daddr_t             blkno,
    1935             :         uint                    len,
    1936             :         const struct xfs_buf_ops *ops)
    1937             : {
    1938    32266373 :         if (!xlog_is_buffer_cancelled(log, blkno, len))
    1939    31417942 :                 xfs_buf_readahead(log->l_mp->m_ddev_targp, blkno, len, ops);
    1940    32266373 : }
    1941             : 
    1942             : STATIC int
    1943      612874 : xlog_recover_items_pass2(
    1944             :         struct xlog                     *log,
    1945             :         struct xlog_recover             *trans,
    1946             :         struct list_head                *buffer_list,
    1947             :         struct list_head                *item_list)
    1948             : {
    1949      612874 :         struct xlog_recover_item        *item;
    1950      612874 :         int                             error = 0;
    1951             : 
    1952    33214694 :         list_for_each_entry(item, item_list, ri_list) {
    1953    32601820 :                 trace_xfs_log_recover_item_recover(log, trans, item,
    1954             :                                 XLOG_RECOVER_PASS2);
    1955             : 
    1956    32601820 :                 if (item->ri_ops->commit_pass2)
    1957    32601820 :                         error = item->ri_ops->commit_pass2(log, buffer_list,
    1958             :                                         item, trans->r_lsn);
    1959    32601820 :                 if (error)
    1960           0 :                         return error;
    1961             :         }
    1962             : 
    1963             :         return error;
    1964             : }
    1965             : 
    1966             : /*
    1967             :  * Perform the transaction.
    1968             :  *
    1969             :  * If the transaction modifies a buffer or inode, do it now.  Otherwise,
    1970             :  * EFIs and EFDs get queued up by adding entries into the AIL for them.
    1971             :  */
    1972             : STATIC int
    1973      904380 : xlog_recover_commit_trans(
    1974             :         struct xlog             *log,
    1975             :         struct xlog_recover     *trans,
    1976             :         int                     pass,
    1977             :         struct list_head        *buffer_list)
    1978             : {
    1979      904380 :         int                             error = 0;
    1980      904380 :         int                             items_queued = 0;
    1981      904380 :         struct xlog_recover_item        *item;
    1982      904380 :         struct xlog_recover_item        *next;
    1983      904380 :         LIST_HEAD                       (ra_list);
    1984      904380 :         LIST_HEAD                       (done_list);
    1985             : 
    1986             :         #define XLOG_RECOVER_COMMIT_QUEUE_MAX 100
    1987             : 
    1988      904380 :         hlist_del_init(&trans->r_list);
    1989             : 
    1990      904380 :         error = xlog_recover_reorder_trans(log, trans, pass);
    1991      904380 :         if (error)
    1992             :                 return error;
    1993             : 
    1994    66108020 :         list_for_each_entry_safe(item, next, &trans->r_itemq, ri_list) {
    1995    65203640 :                 trace_xfs_log_recover_item_recover(log, trans, item, pass);
    1996             : 
    1997    65203640 :                 switch (pass) {
    1998    32601820 :                 case XLOG_RECOVER_PASS1:
    1999    32601820 :                         if (item->ri_ops->commit_pass1)
    2000    16548752 :                                 error = item->ri_ops->commit_pass1(log, item);
    2001             :                         break;
    2002    32601820 :                 case XLOG_RECOVER_PASS2:
    2003    32601820 :                         if (item->ri_ops->ra_pass2)
    2004    32266373 :                                 item->ri_ops->ra_pass2(log, item);
    2005    32601820 :                         list_move_tail(&item->ri_list, &ra_list);
    2006    32601820 :                         items_queued++;
    2007    32601820 :                         if (items_queued >= XLOG_RECOVER_COMMIT_QUEUE_MAX) {
    2008      162776 :                                 error = xlog_recover_items_pass2(log, trans,
    2009             :                                                 buffer_list, &ra_list);
    2010      162776 :                                 list_splice_tail_init(&ra_list, &done_list);
    2011             :                                 items_queued = 0;
    2012             :                         }
    2013             : 
    2014             :                         break;
    2015           0 :                 default:
    2016           0 :                         ASSERT(0);
    2017             :                 }
    2018             : 
    2019    65203640 :                 if (error)
    2020           0 :                         goto out;
    2021             :         }
    2022             : 
    2023      904380 : out:
    2024      904380 :         if (!list_empty(&ra_list)) {
    2025      450098 :                 if (!error)
    2026      450098 :                         error = xlog_recover_items_pass2(log, trans,
    2027             :                                         buffer_list, &ra_list);
    2028      450098 :                 list_splice_tail_init(&ra_list, &done_list);
    2029             :         }
    2030             : 
    2031      904380 :         if (!list_empty(&done_list))
    2032      452190 :                 list_splice_init(&done_list, &trans->r_itemq);
    2033             : 
    2034             :         return error;
    2035             : }
    2036             : 
    2037             : STATIC void
    2038    65436486 : xlog_recover_add_item(
    2039             :         struct list_head        *head)
    2040             : {
    2041    65436486 :         struct xlog_recover_item *item;
    2042             : 
    2043    65436486 :         item = kmem_zalloc(sizeof(struct xlog_recover_item), 0);
    2044    65436486 :         INIT_LIST_HEAD(&item->ri_list);
    2045    65436486 :         list_add_tail(&item->ri_list, head);
    2046    65436486 : }
    2047             : 
    2048             : STATIC int
    2049     2162154 : xlog_recover_add_to_cont_trans(
    2050             :         struct xlog             *log,
    2051             :         struct xlog_recover     *trans,
    2052             :         char                    *dp,
    2053             :         int                     len)
    2054             : {
    2055     2162154 :         struct xlog_recover_item *item;
    2056     2162154 :         char                    *ptr, *old_ptr;
    2057     2162154 :         int                     old_len;
    2058             : 
    2059             :         /*
    2060             :          * If the transaction is empty, the header was split across this and the
    2061             :          * previous record. Copy the rest of the header.
    2062             :          */
    2063     2162154 :         if (list_empty(&trans->r_itemq)) {
    2064          10 :                 ASSERT(len <= sizeof(struct xfs_trans_header));
    2065          10 :                 if (len > sizeof(struct xfs_trans_header)) {
    2066           0 :                         xfs_warn(log->l_mp, "%s: bad header length", __func__);
    2067           0 :                         return -EFSCORRUPTED;
    2068             :                 }
    2069             : 
    2070          10 :                 xlog_recover_add_item(&trans->r_itemq);
    2071          10 :                 ptr = (char *)&trans->r_theader +
    2072          10 :                                 sizeof(struct xfs_trans_header) - len;
    2073          20 :                 memcpy(ptr, dp, len);
    2074          10 :                 return 0;
    2075             :         }
    2076             : 
    2077             :         /* take the tail entry */
    2078     2162144 :         item = list_entry(trans->r_itemq.prev, struct xlog_recover_item,
    2079             :                           ri_list);
    2080             : 
    2081     2162144 :         old_ptr = item->ri_buf[item->ri_cnt-1].i_addr;
    2082     2162144 :         old_len = item->ri_buf[item->ri_cnt-1].i_len;
    2083             : 
    2084     2162144 :         ptr = kvrealloc(old_ptr, old_len, len + old_len, GFP_KERNEL);
    2085     2162144 :         if (!ptr)
    2086             :                 return -ENOMEM;
    2087     4324288 :         memcpy(&ptr[old_len], dp, len);
    2088     2162144 :         item->ri_buf[item->ri_cnt-1].i_len += len;
    2089     2162144 :         item->ri_buf[item->ri_cnt-1].i_addr = ptr;
    2090     2162144 :         trace_xfs_log_recover_item_add_cont(log, trans, item, 0);
    2091     2162144 :         return 0;
    2092             : }
    2093             : 
    2094             : /*
    2095             :  * The next region to add is the start of a new region.  It could be
    2096             :  * a whole region or it could be the first part of a new region.  Because
    2097             :  * of this, the assumption here is that the type and size fields of all
    2098             :  * format structures fit into the first 32 bits of the structure.
    2099             :  *
    2100             :  * This works because all regions must be 32 bit aligned.  Therefore, we
    2101             :  * either have both fields or we have neither field.  In the case we have
    2102             :  * neither field, the data part of the region is zero length.  We only have
    2103             :  * a log_op_header and can throw away the header since a new one will appear
    2104             :  * later.  If we have at least 4 bytes, then we can determine how many regions
    2105             :  * will appear in the current log item.
    2106             :  */
    2107             : STATIC int
    2108   162847070 : xlog_recover_add_to_trans(
    2109             :         struct xlog             *log,
    2110             :         struct xlog_recover     *trans,
    2111             :         char                    *dp,
    2112             :         int                     len)
    2113             : {
    2114   162847070 :         struct xfs_inode_log_format     *in_f;                  /* any will do */
    2115   162847070 :         struct xlog_recover_item *item;
    2116   162847070 :         char                    *ptr;
    2117             : 
    2118   162847070 :         if (!len)
    2119             :                 return 0;
    2120   162847070 :         if (list_empty(&trans->r_itemq)) {
    2121             :                 /* we need to catch log corruptions here */
    2122      906408 :                 if (*(uint *)dp != XFS_TRANS_HEADER_MAGIC) {
    2123           0 :                         xfs_warn(log->l_mp, "%s: bad header magic number",
    2124             :                                 __func__);
    2125           0 :                         ASSERT(0);
    2126           0 :                         return -EFSCORRUPTED;
    2127             :                 }
    2128             : 
    2129      906408 :                 if (len > sizeof(struct xfs_trans_header)) {
    2130           0 :                         xfs_warn(log->l_mp, "%s: bad header length", __func__);
    2131           0 :                         ASSERT(0);
    2132           0 :                         return -EFSCORRUPTED;
    2133             :                 }
    2134             : 
    2135             :                 /*
    2136             :                  * The transaction header can be arbitrarily split across op
    2137             :                  * records. If we don't have the whole thing here, copy what we
    2138             :                  * do have and handle the rest in the next record.
    2139             :                  */
    2140      906408 :                 if (len == sizeof(struct xfs_trans_header))
    2141      906398 :                         xlog_recover_add_item(&trans->r_itemq);
    2142     1812816 :                 memcpy(&trans->r_theader, dp, len);
    2143      906408 :                 return 0;
    2144             :         }
    2145             : 
    2146   161940662 :         ptr = kmem_alloc(len, 0);
    2147   323881324 :         memcpy(ptr, dp, len);
    2148   161940662 :         in_f = (struct xfs_inode_log_format *)ptr;
    2149             : 
    2150             :         /* take the tail entry */
    2151   161940662 :         item = list_entry(trans->r_itemq.prev, struct xlog_recover_item,
    2152             :                           ri_list);
    2153   161940662 :         if (item->ri_total != 0 &&
    2154   161034254 :              item->ri_total == item->ri_cnt) {
    2155             :                 /* tail item is in use, get a new one */
    2156    64530078 :                 xlog_recover_add_item(&trans->r_itemq);
    2157    64530078 :                 item = list_entry(trans->r_itemq.prev,
    2158             :                                         struct xlog_recover_item, ri_list);
    2159             :         }
    2160             : 
    2161   161940662 :         if (item->ri_total == 0) {           /* first region to be added */
    2162    65436486 :                 if (in_f->ilf_size == 0 ||
    2163             :                     in_f->ilf_size > XLOG_MAX_REGIONS_IN_ITEM) {
    2164           0 :                         xfs_warn(log->l_mp,
    2165             :                 "bad number of regions (%d) in inode log format",
    2166             :                                   in_f->ilf_size);
    2167           0 :                         ASSERT(0);
    2168           0 :                         kmem_free(ptr);
    2169           0 :                         return -EFSCORRUPTED;
    2170             :                 }
    2171             : 
    2172    65436486 :                 item->ri_total = in_f->ilf_size;
    2173    65436486 :                 item->ri_buf =
    2174    65436486 :                         kmem_zalloc(item->ri_total * sizeof(xfs_log_iovec_t),
    2175             :                                     0);
    2176             :         }
    2177             : 
    2178   161940662 :         if (item->ri_total <= item->ri_cnt) {
    2179           0 :                 xfs_warn(log->l_mp,
    2180             :         "log item region count (%d) overflowed size (%d)",
    2181             :                                 item->ri_cnt, item->ri_total);
    2182           0 :                 ASSERT(0);
    2183           0 :                 kmem_free(ptr);
    2184           0 :                 return -EFSCORRUPTED;
    2185             :         }
    2186             : 
    2187             :         /* Description region is ri_buf[0] */
    2188   161940662 :         item->ri_buf[item->ri_cnt].i_addr = ptr;
    2189   161940662 :         item->ri_buf[item->ri_cnt].i_len  = len;
    2190   161940662 :         item->ri_cnt++;
    2191   161940662 :         trace_xfs_log_recover_item_add(log, trans, item, 0);
    2192   161940662 :         return 0;
    2193             : }
    2194             : 
    2195             : /*
    2196             :  * Free up any resources allocated by the transaction
    2197             :  *
    2198             :  * Remember that EFIs, EFDs, and IUNLINKs are handled later.
    2199             :  */
    2200             : STATIC void
    2201      906408 : xlog_recover_free_trans(
    2202             :         struct xlog_recover     *trans)
    2203             : {
    2204      906408 :         struct xlog_recover_item *item, *n;
    2205      906408 :         int                     i;
    2206             : 
    2207      906408 :         hlist_del_init(&trans->r_list);
    2208             : 
    2209    66342894 :         list_for_each_entry_safe(item, n, &trans->r_itemq, ri_list) {
    2210             :                 /* Free the regions in the item. */
    2211    65436486 :                 list_del(&item->ri_list);
    2212   227377148 :                 for (i = 0; i < item->ri_cnt; i++)
    2213   161940662 :                         kmem_free(item->ri_buf[i].i_addr);
    2214             :                 /* Free the item itself */
    2215    65436486 :                 kmem_free(item->ri_buf);
    2216    65436486 :                 kmem_free(item);
    2217             :         }
    2218             :         /* Free the transaction recover structure */
    2219      906408 :         kmem_free(trans);
    2220      906408 : }
    2221             : 
    2222             : /*
    2223             :  * On error or completion, trans is freed.
    2224             :  */
    2225             : STATIC int
    2226   165913604 : xlog_recovery_process_trans(
    2227             :         struct xlog             *log,
    2228             :         struct xlog_recover     *trans,
    2229             :         char                    *dp,
    2230             :         unsigned int            len,
    2231             :         unsigned int            flags,
    2232             :         int                     pass,
    2233             :         struct list_head        *buffer_list)
    2234             : {
    2235   165913604 :         int                     error = 0;
    2236   165913604 :         bool                    freeit = false;
    2237             : 
    2238             :         /* mask off ophdr transaction container flags */
    2239   165913604 :         flags &= ~XLOG_END_TRANS;
    2240   165913604 :         if (flags & XLOG_WAS_CONT_TRANS)
    2241     2162154 :                 flags &= ~XLOG_CONTINUE_TRANS;
    2242             : 
    2243             :         /*
    2244             :          * Callees must not free the trans structure. We'll decide if we need to
    2245             :          * free it or not based on the operation being done and it's result.
    2246             :          */
    2247   165913604 :         switch (flags) {
    2248             :         /* expected flag values */
    2249   162847070 :         case 0:
    2250             :         case XLOG_CONTINUE_TRANS:
    2251   162847070 :                 error = xlog_recover_add_to_trans(log, trans, dp, len);
    2252   162847070 :                 break;
    2253     2162154 :         case XLOG_WAS_CONT_TRANS:
    2254     2162154 :                 error = xlog_recover_add_to_cont_trans(log, trans, dp, len);
    2255     2162154 :                 break;
    2256      904380 :         case XLOG_COMMIT_TRANS:
    2257      904380 :                 error = xlog_recover_commit_trans(log, trans, pass,
    2258             :                                                   buffer_list);
    2259             :                 /* success or fail, we are now done with this transaction. */
    2260      904380 :                 freeit = true;
    2261      904380 :                 break;
    2262             : 
    2263             :         /* unexpected flag values */
    2264           0 :         case XLOG_UNMOUNT_TRANS:
    2265             :                 /* just skip trans */
    2266           0 :                 xfs_warn(log->l_mp, "%s: Unmount LR", __func__);
    2267           0 :                 freeit = true;
    2268           0 :                 break;
    2269           0 :         case XLOG_START_TRANS:
    2270             :         default:
    2271           0 :                 xfs_warn(log->l_mp, "%s: bad flag 0x%x", __func__, flags);
    2272           0 :                 ASSERT(0);
    2273           0 :                 error = -EFSCORRUPTED;
    2274           0 :                 break;
    2275             :         }
    2276   165913604 :         if (error || freeit)
    2277      904380 :                 xlog_recover_free_trans(trans);
    2278   165913604 :         return error;
    2279             : }
    2280             : 
    2281             : /*
    2282             :  * Lookup the transaction recovery structure associated with the ID in the
    2283             :  * current ophdr. If the transaction doesn't exist and the start flag is set in
    2284             :  * the ophdr, then allocate a new transaction for future ID matches to find.
    2285             :  * Either way, return what we found during the lookup - an existing transaction
    2286             :  * or nothing.
    2287             :  */
    2288             : STATIC struct xlog_recover *
    2289   166875628 : xlog_recover_ophdr_to_trans(
    2290             :         struct hlist_head       rhash[],
    2291             :         struct xlog_rec_header  *rhead,
    2292             :         struct xlog_op_header   *ohead)
    2293             : {
    2294   166875628 :         struct xlog_recover     *trans;
    2295   166875628 :         xlog_tid_t              tid;
    2296   166875628 :         struct hlist_head       *rhp;
    2297             : 
    2298   166875628 :         tid = be32_to_cpu(ohead->oh_tid);
    2299   166875628 :         rhp = &rhash[XLOG_RHASH(tid)];
    2300   333775914 :         hlist_for_each_entry(trans, rhp, r_list) {
    2301   165938262 :                 if (trans->r_log_tid == tid)
    2302   165913604 :                         return trans;
    2303             :         }
    2304             : 
    2305             :         /*
    2306             :          * skip over non-start transaction headers - we could be
    2307             :          * processing slack space before the next transaction starts
    2308             :          */
    2309      962024 :         if (!(ohead->oh_flags & XLOG_START_TRANS))
    2310             :                 return NULL;
    2311             : 
    2312      906408 :         ASSERT(be32_to_cpu(ohead->oh_len) == 0);
    2313             : 
    2314             :         /*
    2315             :          * This is a new transaction so allocate a new recovery container to
    2316             :          * hold the recovery ops that will follow.
    2317             :          */
    2318      906408 :         trans = kmem_zalloc(sizeof(struct xlog_recover), 0);
    2319      906408 :         trans->r_log_tid = tid;
    2320      906408 :         trans->r_lsn = be64_to_cpu(rhead->h_lsn);
    2321      906408 :         INIT_LIST_HEAD(&trans->r_itemq);
    2322      906408 :         INIT_HLIST_NODE(&trans->r_list);
    2323      906408 :         hlist_add_head(&trans->r_list, rhp);
    2324             : 
    2325             :         /*
    2326             :          * Nothing more to do for this ophdr. Items to be added to this new
    2327             :          * transaction will be in subsequent ophdr containers.
    2328             :          */
    2329      906408 :         return NULL;
    2330             : }
    2331             : 
    2332             : STATIC int
    2333   166875628 : xlog_recover_process_ophdr(
    2334             :         struct xlog             *log,
    2335             :         struct hlist_head       rhash[],
    2336             :         struct xlog_rec_header  *rhead,
    2337             :         struct xlog_op_header   *ohead,
    2338             :         char                    *dp,
    2339             :         char                    *end,
    2340             :         int                     pass,
    2341             :         struct list_head        *buffer_list)
    2342             : {
    2343   166875628 :         struct xlog_recover     *trans;
    2344   166875628 :         unsigned int            len;
    2345   166875628 :         int                     error;
    2346             : 
    2347             :         /* Do we understand who wrote this op? */
    2348   166875628 :         if (ohead->oh_clientid != XFS_TRANSACTION &&
    2349             :             ohead->oh_clientid != XFS_LOG) {
    2350           0 :                 xfs_warn(log->l_mp, "%s: bad clientid 0x%x",
    2351             :                         __func__, ohead->oh_clientid);
    2352           0 :                 ASSERT(0);
    2353           0 :                 return -EFSCORRUPTED;
    2354             :         }
    2355             : 
    2356             :         /*
    2357             :          * Check the ophdr contains all the data it is supposed to contain.
    2358             :          */
    2359   166875628 :         len = be32_to_cpu(ohead->oh_len);
    2360   166875628 :         if (dp + len > end) {
    2361           0 :                 xfs_warn(log->l_mp, "%s: bad length 0x%x", __func__, len);
    2362           0 :                 WARN_ON(1);
    2363           0 :                 return -EFSCORRUPTED;
    2364             :         }
    2365             : 
    2366   166875628 :         trans = xlog_recover_ophdr_to_trans(rhash, rhead, ohead);
    2367   166875628 :         if (!trans) {
    2368             :                 /* nothing to do, so skip over this ophdr */
    2369             :                 return 0;
    2370             :         }
    2371             : 
    2372             :         /*
    2373             :          * The recovered buffer queue is drained only once we know that all
    2374             :          * recovery items for the current LSN have been processed. This is
    2375             :          * required because:
    2376             :          *
    2377             :          * - Buffer write submission updates the metadata LSN of the buffer.
    2378             :          * - Log recovery skips items with a metadata LSN >= the current LSN of
    2379             :          *   the recovery item.
    2380             :          * - Separate recovery items against the same metadata buffer can share
    2381             :          *   a current LSN. I.e., consider that the LSN of a recovery item is
    2382             :          *   defined as the starting LSN of the first record in which its
    2383             :          *   transaction appears, that a record can hold multiple transactions,
    2384             :          *   and/or that a transaction can span multiple records.
    2385             :          *
    2386             :          * In other words, we are allowed to submit a buffer from log recovery
    2387             :          * once per current LSN. Otherwise, we may incorrectly skip recovery
    2388             :          * items and cause corruption.
    2389             :          *
    2390             :          * We don't know up front whether buffers are updated multiple times per
    2391             :          * LSN. Therefore, track the current LSN of each commit log record as it
    2392             :          * is processed and drain the queue when it changes. Use commit records
    2393             :          * because they are ordered correctly by the logging code.
    2394             :          */
    2395   165913604 :         if (log->l_recovery_lsn != trans->r_lsn &&
    2396   165210814 :             ohead->oh_flags & XLOG_COMMIT_TRANS) {
    2397      901069 :                 error = xfs_buf_delwri_submit(buffer_list);
    2398      901069 :                 if (error)
    2399             :                         return error;
    2400      901069 :                 log->l_recovery_lsn = trans->r_lsn;
    2401             :         }
    2402             : 
    2403   165913604 :         return xlog_recovery_process_trans(log, trans, dp, len,
    2404   165913604 :                                            ohead->oh_flags, pass, buffer_list);
    2405             : }
    2406             : 
    2407             : /*
    2408             :  * There are two valid states of the r_state field.  0 indicates that the
    2409             :  * transaction structure is in a normal state.  We have either seen the
    2410             :  * start of the transaction or the last operation we added was not a partial
    2411             :  * operation.  If the last operation we added to the transaction was a
    2412             :  * partial operation, we need to mark r_state with XLOG_WAS_CONT_TRANS.
    2413             :  *
    2414             :  * NOTE: skip LRs with 0 data length.
    2415             :  */
    2416             : STATIC int
    2417     3124608 : xlog_recover_process_data(
    2418             :         struct xlog             *log,
    2419             :         struct hlist_head       rhash[],
    2420             :         struct xlog_rec_header  *rhead,
    2421             :         char                    *dp,
    2422             :         int                     pass,
    2423             :         struct list_head        *buffer_list)
    2424             : {
    2425     3124608 :         struct xlog_op_header   *ohead;
    2426     3124608 :         char                    *end;
    2427     3124608 :         int                     num_logops;
    2428     3124608 :         int                     error;
    2429             : 
    2430     3124608 :         end = dp + be32_to_cpu(rhead->h_len);
    2431     3124608 :         num_logops = be32_to_cpu(rhead->h_num_logops);
    2432             : 
    2433             :         /* check the log format matches our own - else we can't recover */
    2434     3124608 :         if (xlog_header_check_recover(log->l_mp, rhead))
    2435             :                 return -EIO;
    2436             : 
    2437     3124608 :         trace_xfs_log_recover_record(log, rhead, pass);
    2438   170000236 :         while ((dp < end) && num_logops) {
    2439             : 
    2440   166875628 :                 ohead = (struct xlog_op_header *)dp;
    2441   166875628 :                 dp += sizeof(*ohead);
    2442   166875628 :                 ASSERT(dp <= end);
    2443             : 
    2444             :                 /* errors will abort recovery */
    2445   166875628 :                 error = xlog_recover_process_ophdr(log, rhash, rhead, ohead,
    2446             :                                                    dp, end, pass, buffer_list);
    2447   166875628 :                 if (error)
    2448           0 :                         return error;
    2449             : 
    2450   166875628 :                 dp += be32_to_cpu(ohead->oh_len);
    2451   166875628 :                 num_logops--;
    2452             :         }
    2453             :         return 0;
    2454             : }
    2455             : 
    2456             : /* Take all the collected deferred ops and finish them in order. */
    2457             : static int
    2458       13717 : xlog_finish_defer_ops(
    2459             :         struct xfs_mount        *mp,
    2460             :         struct list_head        *capture_list)
    2461             : {
    2462       13717 :         struct xfs_defer_capture *dfc, *next;
    2463       13717 :         struct xfs_trans        *tp;
    2464       13717 :         int                     error = 0;
    2465             : 
    2466       15057 :         list_for_each_entry_safe(dfc, next, capture_list, dfc_list) {
    2467        1340 :                 struct xfs_trans_res    resv;
    2468        1340 :                 struct xfs_defer_resources dres;
    2469             : 
    2470             :                 /*
    2471             :                  * Create a new transaction reservation from the captured
    2472             :                  * information.  Set logcount to 1 to force the new transaction
    2473             :                  * to regrant every roll so that we can make forward progress
    2474             :                  * in recovery no matter how full the log might be.
    2475             :                  */
    2476        1340 :                 resv.tr_logres = dfc->dfc_logres;
    2477        1340 :                 resv.tr_logcount = 1;
    2478        1340 :                 resv.tr_logflags = XFS_TRANS_PERM_LOG_RES;
    2479             : 
    2480        1340 :                 error = xfs_trans_alloc(mp, &resv, dfc->dfc_blkres,
    2481             :                                 dfc->dfc_rtxres, XFS_TRANS_RESERVE, &tp);
    2482        1340 :                 if (error) {
    2483           0 :                         xlog_force_shutdown(mp->m_log, SHUTDOWN_LOG_IO_ERROR);
    2484           0 :                         return error;
    2485             :                 }
    2486             : 
    2487             :                 /*
    2488             :                  * Transfer to this new transaction all the dfops we captured
    2489             :                  * from recovering a single intent item.
    2490             :                  */
    2491        1340 :                 list_del_init(&dfc->dfc_list);
    2492        1340 :                 xfs_defer_ops_continue(dfc, tp, &dres);
    2493        1340 :                 error = xfs_trans_commit(tp);
    2494        1340 :                 xfs_defer_resources_rele(&dres);
    2495        1340 :                 if (error)
    2496           0 :                         return error;
    2497             :         }
    2498             : 
    2499       13717 :         ASSERT(list_empty(capture_list));
    2500             :         return 0;
    2501             : }
    2502             : 
    2503             : /* Release all the captured defer ops and capture structures in this list. */
    2504             : static void
    2505           6 : xlog_abort_defer_ops(
    2506             :         struct xfs_mount                *mp,
    2507             :         struct list_head                *capture_list)
    2508             : {
    2509           6 :         struct xfs_defer_capture        *dfc;
    2510           6 :         struct xfs_defer_capture        *next;
    2511             : 
    2512           6 :         list_for_each_entry_safe(dfc, next, capture_list, dfc_list) {
    2513           0 :                 list_del_init(&dfc->dfc_list);
    2514           0 :                 xfs_defer_ops_capture_abort(mp, dfc);
    2515             :         }
    2516           6 : }
    2517             : 
    2518             : /*
    2519             :  * When this is called, all of the log intent items which did not have
    2520             :  * corresponding log done items should be in the AIL.  What we do now is update
    2521             :  * the data structures associated with each one.
    2522             :  *
    2523             :  * Since we process the log intent items in normal transactions, they will be
    2524             :  * removed at some point after the commit.  This prevents us from just walking
    2525             :  * down the list processing each one.  We'll use a flag in the intent item to
    2526             :  * skip those that we've already processed and use the AIL iteration mechanism's
    2527             :  * generation count to try to speed this up at least a bit.
    2528             :  *
    2529             :  * When we start, we know that the intents are the only things in the AIL. As we
    2530             :  * process them, however, other items are added to the AIL. Hence we know we
    2531             :  * have started recovery on all the pending intents when we find an non-intent
    2532             :  * item in the AIL.
    2533             :  */
    2534             : STATIC int
    2535       13723 : xlog_recover_process_intents(
    2536             :         struct xlog             *log)
    2537             : {
    2538       13723 :         LIST_HEAD(capture_list);
    2539       13723 :         struct xfs_ail_cursor   cur;
    2540       13723 :         struct xfs_log_item     *lip;
    2541       13723 :         struct xfs_ail          *ailp;
    2542       13723 :         int                     error = 0;
    2543             : #if defined(DEBUG) || defined(XFS_WARN)
    2544       13723 :         xfs_lsn_t               last_lsn;
    2545             : #endif
    2546             : 
    2547       13723 :         ailp = log->l_ailp;
    2548       13723 :         spin_lock(&ailp->ail_lock);
    2549             : #if defined(DEBUG) || defined(XFS_WARN)
    2550       13723 :         last_lsn = xlog_assign_lsn(log->l_curr_cycle, log->l_curr_block);
    2551             : #endif
    2552       13723 :         for (lip = xfs_trans_ail_cursor_first(ailp, &cur, 0);
    2553       19219 :              lip != NULL;
    2554        5496 :              lip = xfs_trans_ail_cursor_next(ailp, &cur)) {
    2555        5502 :                 const struct xfs_item_ops       *ops;
    2556             : 
    2557        5502 :                 if (!xlog_item_is_intent(lip))
    2558             :                         break;
    2559             : 
    2560             :                 /*
    2561             :                  * We should never see a redo item with a LSN higher than
    2562             :                  * the last transaction we found in the log at the start
    2563             :                  * of recovery.
    2564             :                  */
    2565       11004 :                 ASSERT(XFS_LSN_CMP(last_lsn, lip->li_lsn) >= 0);
    2566             : 
    2567             :                 /*
    2568             :                  * NOTE: If your intent processing routine can create more
    2569             :                  * deferred ops, you /must/ attach them to the capture list in
    2570             :                  * the recover routine or else those subsequent intents will be
    2571             :                  * replayed in the wrong order!
    2572             :                  *
    2573             :                  * The recovery function can free the log item, so we must not
    2574             :                  * access lip after it returns.
    2575             :                  */
    2576        5502 :                 spin_unlock(&ailp->ail_lock);
    2577        5502 :                 ops = lip->li_ops;
    2578        5502 :                 error = ops->iop_recover(lip, &capture_list);
    2579        5502 :                 spin_lock(&ailp->ail_lock);
    2580        5502 :                 if (error) {
    2581           6 :                         trace_xlog_intent_recovery_failed(log->l_mp, error,
    2582           6 :                                         ops->iop_recover);
    2583           6 :                         break;
    2584             :                 }
    2585             :         }
    2586             : 
    2587       13723 :         xfs_trans_ail_cursor_done(&cur);
    2588       13723 :         spin_unlock(&ailp->ail_lock);
    2589       13723 :         if (error)
    2590           6 :                 goto err;
    2591             : 
    2592       13717 :         error = xlog_finish_defer_ops(log->l_mp, &capture_list);
    2593       13717 :         if (error)
    2594           0 :                 goto err;
    2595             : 
    2596             :         return 0;
    2597           6 : err:
    2598           6 :         xlog_abort_defer_ops(log->l_mp, &capture_list);
    2599           6 :         return error;
    2600             : }
    2601             : 
    2602             : /*
    2603             :  * A cancel occurs when the mount has failed and we're bailing out.  Release all
    2604             :  * pending log intent items that we haven't started recovery on so they don't
    2605             :  * pin the AIL.
    2606             :  */
    2607             : STATIC void
    2608           6 : xlog_recover_cancel_intents(
    2609             :         struct xlog             *log)
    2610             : {
    2611           6 :         struct xfs_log_item     *lip;
    2612           6 :         struct xfs_ail_cursor   cur;
    2613           6 :         struct xfs_ail          *ailp;
    2614             : 
    2615           6 :         ailp = log->l_ailp;
    2616           6 :         spin_lock(&ailp->ail_lock);
    2617           6 :         lip = xfs_trans_ail_cursor_first(ailp, &cur, 0);
    2618           6 :         while (lip != NULL) {
    2619           0 :                 if (!xlog_item_is_intent(lip))
    2620             :                         break;
    2621             : 
    2622           0 :                 spin_unlock(&ailp->ail_lock);
    2623           0 :                 lip->li_ops->iop_release(lip);
    2624           0 :                 spin_lock(&ailp->ail_lock);
    2625           0 :                 lip = xfs_trans_ail_cursor_next(ailp, &cur);
    2626             :         }
    2627             : 
    2628           6 :         xfs_trans_ail_cursor_done(&cur);
    2629           6 :         spin_unlock(&ailp->ail_lock);
    2630           6 : }
    2631             : 
    2632             : /*
    2633             :  * This routine performs a transaction to null out a bad inode pointer
    2634             :  * in an agi unlinked inode hash bucket.
    2635             :  */
    2636             : STATIC void
    2637          10 : xlog_recover_clear_agi_bucket(
    2638             :         struct xfs_perag        *pag,
    2639             :         int                     bucket)
    2640             : {
    2641          10 :         struct xfs_mount        *mp = pag->pag_mount;
    2642          10 :         struct xfs_trans        *tp;
    2643          10 :         struct xfs_agi          *agi;
    2644          10 :         struct xfs_buf          *agibp;
    2645          10 :         int                     offset;
    2646          10 :         int                     error;
    2647             : 
    2648          10 :         error = xfs_trans_alloc(mp, &M_RES(mp)->tr_clearagi, 0, 0, 0, &tp);
    2649          10 :         if (error)
    2650          10 :                 goto out_error;
    2651             : 
    2652           0 :         error = xfs_read_agi(pag, tp, &agibp);
    2653           0 :         if (error)
    2654           0 :                 goto out_abort;
    2655             : 
    2656           0 :         agi = agibp->b_addr;
    2657           0 :         agi->agi_unlinked[bucket] = cpu_to_be32(NULLAGINO);
    2658           0 :         offset = offsetof(xfs_agi_t, agi_unlinked) +
    2659             :                  (sizeof(xfs_agino_t) * bucket);
    2660           0 :         xfs_trans_log_buf(tp, agibp, offset,
    2661             :                           (offset + sizeof(xfs_agino_t) - 1));
    2662             : 
    2663           0 :         error = xfs_trans_commit(tp);
    2664           0 :         if (error)
    2665           0 :                 goto out_error;
    2666             :         return;
    2667             : 
    2668             : out_abort:
    2669           0 :         xfs_trans_cancel(tp);
    2670          10 : out_error:
    2671          10 :         xfs_warn(mp, "%s: failed to clear agi %d. Continuing.", __func__,
    2672             :                         pag->pag_agno);
    2673          10 :         return;
    2674             : }
    2675             : 
    2676             : static int
    2677     3740160 : xlog_recover_iunlink_bucket(
    2678             :         struct xfs_perag        *pag,
    2679             :         struct xfs_agi          *agi,
    2680             :         int                     bucket)
    2681             : {
    2682     3740160 :         struct xfs_mount        *mp = pag->pag_mount;
    2683     3740160 :         struct xfs_inode        *prev_ip = NULL;
    2684     3740160 :         struct xfs_inode        *ip;
    2685     3740160 :         xfs_agino_t             prev_agino, agino;
    2686     3740160 :         int                     error = 0;
    2687             : 
    2688     3740160 :         agino = be32_to_cpu(agi->agi_unlinked[bucket]);
    2689     4635345 :         while (agino != NULLAGINO) {
    2690     1790370 :                 error = xfs_iget(mp, NULL,
    2691      895185 :                                 XFS_AGINO_TO_INO(mp, pag->pag_agno, agino),
    2692             :                                 0, 0, &ip);
    2693      895185 :                 if (error)
    2694             :                         break;
    2695             : 
    2696      895185 :                 ASSERT(VFS_I(ip)->i_nlink == 0);
    2697      895185 :                 ASSERT(VFS_I(ip)->i_mode != 0);
    2698      895185 :                 xfs_iflags_clear(ip, XFS_IRECOVERY);
    2699      895185 :                 agino = ip->i_next_unlinked;
    2700             : 
    2701      895185 :                 if (prev_ip) {
    2702      885979 :                         ip->i_prev_unlinked = prev_agino;
    2703      885979 :                         xfs_irele(prev_ip);
    2704             : 
    2705             :                         /*
    2706             :                          * Ensure the inode is removed from the unlinked list
    2707             :                          * before we continue so that it won't race with
    2708             :                          * building the in-memory list here. This could be
    2709             :                          * serialised with the agibp lock, but that just
    2710             :                          * serialises via lockstepping and it's much simpler
    2711             :                          * just to flush the inodegc queue and wait for it to
    2712             :                          * complete.
    2713             :                          */
    2714      885979 :                         error = xfs_inodegc_flush(mp);
    2715      885979 :                         if (error)
    2716             :                                 break;
    2717             :                 }
    2718             : 
    2719      895185 :                 prev_agino = agino;
    2720      895185 :                 prev_ip = ip;
    2721             :         }
    2722             : 
    2723     3740160 :         if (prev_ip) {
    2724        9206 :                 int     error2;
    2725             : 
    2726        9206 :                 ip->i_prev_unlinked = prev_agino;
    2727        9206 :                 xfs_irele(prev_ip);
    2728             : 
    2729        9206 :                 error2 = xfs_inodegc_flush(mp);
    2730        9206 :                 if (error2 && !error)
    2731          10 :                         return error2;
    2732             :         }
    2733             :         return error;
    2734             : }
    2735             : 
    2736             : /*
    2737             :  * Recover AGI unlinked lists
    2738             :  *
    2739             :  * This is called during recovery to process any inodes which we unlinked but
    2740             :  * not freed when the system crashed.  These inodes will be on the lists in the
    2741             :  * AGI blocks. What we do here is scan all the AGIs and fully truncate and free
    2742             :  * any inodes found on the lists. Each inode is removed from the lists when it
    2743             :  * has been fully truncated and is freed. The freeing of the inode and its
    2744             :  * removal from the list must be atomic.
    2745             :  *
    2746             :  * If everything we touch in the agi processing loop is already in memory, this
    2747             :  * loop can hold the cpu for a long time. It runs without lock contention,
    2748             :  * memory allocation contention, the need wait for IO, etc, and so will run
    2749             :  * until we either run out of inodes to process, run low on memory or we run out
    2750             :  * of log space.
    2751             :  *
    2752             :  * This behaviour is bad for latency on single CPU and non-preemptible kernels,
    2753             :  * and can prevent other filesystem work (such as CIL pushes) from running. This
    2754             :  * can lead to deadlocks if the recovery process runs out of log reservation
    2755             :  * space. Hence we need to yield the CPU when there is other kernel work
    2756             :  * scheduled on this CPU to ensure other scheduled work can run without undue
    2757             :  * latency.
    2758             :  */
    2759             : static void
    2760       58494 : xlog_recover_iunlink_ag(
    2761             :         struct xfs_perag        *pag)
    2762             : {
    2763       58494 :         struct xfs_agi          *agi;
    2764       58494 :         struct xfs_buf          *agibp;
    2765       58494 :         int                     bucket;
    2766       58494 :         int                     error;
    2767             : 
    2768       58494 :         error = xfs_read_agi(pag, NULL, &agibp);
    2769       58494 :         if (error) {
    2770             :                 /*
    2771             :                  * AGI is b0rked. Don't process it.
    2772             :                  *
    2773             :                  * We should probably mark the filesystem as corrupt after we've
    2774             :                  * recovered all the ag's we can....
    2775             :                  */
    2776          54 :                 return;
    2777             :         }
    2778             : 
    2779             :         /*
    2780             :          * Unlock the buffer so that it can be acquired in the normal course of
    2781             :          * the transaction to truncate and free each inode.  Because we are not
    2782             :          * racing with anyone else here for the AGI buffer, we don't even need
    2783             :          * to hold it locked to read the initial unlinked bucket entries out of
    2784             :          * the buffer. We keep buffer reference though, so that it stays pinned
    2785             :          * in memory while we need the buffer.
    2786             :          */
    2787       58440 :         agi = agibp->b_addr;
    2788       58440 :         xfs_buf_unlock(agibp);
    2789             : 
    2790     3857040 :         for (bucket = 0; bucket < XFS_AGI_UNLINKED_BUCKETS; bucket++) {
    2791     3740160 :                 error = xlog_recover_iunlink_bucket(pag, agi, bucket);
    2792     3740160 :                 if (error) {
    2793             :                         /*
    2794             :                          * Bucket is unrecoverable, so only a repair scan can
    2795             :                          * free the remaining unlinked inodes. Just empty the
    2796             :                          * bucket and remaining inodes on it unreferenced and
    2797             :                          * unfreeable.
    2798             :                          */
    2799          10 :                         xlog_recover_clear_agi_bucket(pag, bucket);
    2800             :                 }
    2801             :         }
    2802             : 
    2803       58440 :         xfs_buf_rele(agibp);
    2804             : }
    2805             : 
    2806             : static void
    2807       13717 : xlog_recover_process_iunlinks(
    2808             :         struct xlog     *log)
    2809             : {
    2810       13717 :         struct xfs_perag        *pag;
    2811       13717 :         xfs_agnumber_t          agno;
    2812             : 
    2813       72211 :         for_each_perag(log->l_mp, agno, pag)
    2814       58494 :                 xlog_recover_iunlink_ag(pag);
    2815       13717 : }
    2816             : 
    2817             : STATIC void
    2818     3124608 : xlog_unpack_data(
    2819             :         struct xlog_rec_header  *rhead,
    2820             :         char                    *dp,
    2821             :         struct xlog             *log)
    2822             : {
    2823     3124608 :         int                     i, j, k;
    2824             : 
    2825   171072186 :         for (i = 0; i < BTOBB(be32_to_cpu(rhead->h_len)) &&
    2826   167947578 :                   i < (XLOG_HEADER_CYCLE_SIZE / BBSIZE); i++) {
    2827   167947578 :                 *(__be32 *)dp = *(__be32 *)&rhead->h_cycle_data[i];
    2828   167947578 :                 dp += BBSIZE;
    2829             :         }
    2830             : 
    2831     3124608 :         if (xfs_has_logv2(log->l_mp)) {
    2832             :                 xlog_in_core_2_t *xhdr = (xlog_in_core_2_t *)rhead;
    2833     4749354 :                 for ( ; i < BTOBB(be32_to_cpu(rhead->h_len)); i++) {
    2834     1624746 :                         j = i / (XLOG_HEADER_CYCLE_SIZE / BBSIZE);
    2835     1624746 :                         k = i % (XLOG_HEADER_CYCLE_SIZE / BBSIZE);
    2836     1624746 :                         *(__be32 *)dp = xhdr[j].hic_xheader.xh_cycle_data[k];
    2837     1624746 :                         dp += BBSIZE;
    2838             :                 }
    2839             :         }
    2840     3124608 : }
    2841             : 
    2842             : /*
    2843             :  * CRC check, unpack and process a log record.
    2844             :  */
    2845             : STATIC int
    2846     4765274 : xlog_recover_process(
    2847             :         struct xlog             *log,
    2848             :         struct hlist_head       rhash[],
    2849             :         struct xlog_rec_header  *rhead,
    2850             :         char                    *dp,
    2851             :         int                     pass,
    2852             :         struct list_head        *buffer_list)
    2853             : {
    2854     4765274 :         __le32                  old_crc = rhead->h_crc;
    2855     4765274 :         __le32                  crc;
    2856             : 
    2857     4765274 :         crc = xlog_cksum(log, rhead, dp, be32_to_cpu(rhead->h_len));
    2858             : 
    2859             :         /*
    2860             :          * Nothing else to do if this is a CRC verification pass. Just return
    2861             :          * if this a record with a non-zero crc. Unfortunately, mkfs always
    2862             :          * sets old_crc to 0 so we must consider this valid even on v5 supers.
    2863             :          * Otherwise, return EFSBADCRC on failure so the callers up the stack
    2864             :          * know precisely what failed.
    2865             :          */
    2866     4765274 :         if (pass == XLOG_RECOVER_CRCPASS) {
    2867     1640666 :                 if (old_crc && crc != old_crc)
    2868             :                         return -EFSBADCRC;
    2869     1640610 :                 return 0;
    2870             :         }
    2871             : 
    2872             :         /*
    2873             :          * We're in the normal recovery path. Issue a warning if and only if the
    2874             :          * CRC in the header is non-zero. This is an advisory warning and the
    2875             :          * zero CRC check prevents warnings from being emitted when upgrading
    2876             :          * the kernel from one that does not add CRCs by default.
    2877             :          */
    2878     3124608 :         if (crc != old_crc) {
    2879           0 :                 if (old_crc || xfs_has_crc(log->l_mp)) {
    2880           0 :                         xfs_alert(log->l_mp,
    2881             :                 "log record CRC mismatch: found 0x%x, expected 0x%x.",
    2882             :                                         le32_to_cpu(old_crc),
    2883             :                                         le32_to_cpu(crc));
    2884           0 :                         xfs_hex_dump(dp, 32);
    2885             :                 }
    2886             : 
    2887             :                 /*
    2888             :                  * If the filesystem is CRC enabled, this mismatch becomes a
    2889             :                  * fatal log corruption failure.
    2890             :                  */
    2891           0 :                 if (xfs_has_crc(log->l_mp)) {
    2892           0 :                         XFS_ERROR_REPORT(__func__, XFS_ERRLEVEL_LOW, log->l_mp);
    2893           0 :                         return -EFSCORRUPTED;
    2894             :                 }
    2895             :         }
    2896             : 
    2897     3124608 :         xlog_unpack_data(rhead, dp, log);
    2898             : 
    2899     3124608 :         return xlog_recover_process_data(log, rhash, rhead, dp, pass,
    2900             :                                          buffer_list);
    2901             : }
    2902             : 
    2903             : STATIC int
    2904     4820190 : xlog_valid_rec_header(
    2905             :         struct xlog             *log,
    2906             :         struct xlog_rec_header  *rhead,
    2907             :         xfs_daddr_t             blkno,
    2908             :         int                     bufsize)
    2909             : {
    2910     4820190 :         int                     hlen;
    2911             : 
    2912     4820190 :         if (XFS_IS_CORRUPT(log->l_mp,
    2913             :                            rhead->h_magicno != cpu_to_be32(XLOG_HEADER_MAGIC_NUM)))
    2914           0 :                 return -EFSCORRUPTED;
    2915     4820190 :         if (XFS_IS_CORRUPT(log->l_mp,
    2916             :                            (!rhead->h_version ||
    2917             :                            (be32_to_cpu(rhead->h_version) &
    2918             :                             (~XLOG_VERSION_OKBITS))))) {
    2919           0 :                 xfs_warn(log->l_mp, "%s: unrecognised log version (%d).",
    2920             :                         __func__, be32_to_cpu(rhead->h_version));
    2921           0 :                 return -EFSCORRUPTED;
    2922             :         }
    2923             : 
    2924             :         /*
    2925             :          * LR body must have data (or it wouldn't have been written)
    2926             :          * and h_len must not be greater than LR buffer size.
    2927             :          */
    2928     4820190 :         hlen = be32_to_cpu(rhead->h_len);
    2929     4820190 :         if (XFS_IS_CORRUPT(log->l_mp, hlen <= 0 || hlen > bufsize))
    2930           0 :                 return -EFSCORRUPTED;
    2931             : 
    2932     4820190 :         if (XFS_IS_CORRUPT(log->l_mp,
    2933             :                            blkno > log->l_logBBsize || blkno > INT_MAX))
    2934           0 :                 return -EFSCORRUPTED;
    2935             :         return 0;
    2936             : }
    2937             : 
    2938             : /*
    2939             :  * Read the log from tail to head and process the log records found.
    2940             :  * Handle the two cases where the tail and head are in the same cycle
    2941             :  * and where the active portion of the log wraps around the end of
    2942             :  * the physical log separately.  The pass parameter is passed through
    2943             :  * to the routines called to process the data and is not looked at
    2944             :  * here.
    2945             :  */
    2946             : STATIC int
    2947       54916 : xlog_do_recovery_pass(
    2948             :         struct xlog             *log,
    2949             :         xfs_daddr_t             head_blk,
    2950             :         xfs_daddr_t             tail_blk,
    2951             :         int                     pass,
    2952             :         xfs_daddr_t             *first_bad)     /* out: first bad log rec */
    2953             : {
    2954       54916 :         xlog_rec_header_t       *rhead;
    2955       54916 :         xfs_daddr_t             blk_no, rblk_no;
    2956       54916 :         xfs_daddr_t             rhead_blk;
    2957       54916 :         char                    *offset;
    2958       54916 :         char                    *hbp, *dbp;
    2959       54916 :         int                     error = 0, h_size, h_len;
    2960       54916 :         int                     error2 = 0;
    2961       54916 :         int                     bblks, split_bblks;
    2962       54916 :         int                     hblks, split_hblks, wrapped_hblks;
    2963       54916 :         int                     i;
    2964       54916 :         struct hlist_head       rhash[XLOG_RHASH_SIZE];
    2965       54916 :         LIST_HEAD               (buffer_list);
    2966             : 
    2967       54916 :         ASSERT(head_blk != tail_blk);
    2968             :         blk_no = rhead_blk = tail_blk;
    2969             : 
    2970      933572 :         for (i = 0; i < XLOG_RHASH_SIZE; i++)
    2971      878656 :                 INIT_HLIST_HEAD(&rhash[i]);
    2972             : 
    2973             :         /*
    2974             :          * Read the header of the tail block and get the iclog buffer size from
    2975             :          * h_size.  Use this to tell how many sectors make up the log header.
    2976             :          */
    2977       54916 :         if (xfs_has_logv2(log->l_mp)) {
    2978             :                 /*
    2979             :                  * When using variable length iclogs, read first sector of
    2980             :                  * iclog header and extract the header size from it.  Get a
    2981             :                  * new hbp that is the correct size.
    2982             :                  */
    2983       54916 :                 hbp = xlog_alloc_buffer(log, 1);
    2984       54916 :                 if (!hbp)
    2985             :                         return -ENOMEM;
    2986             : 
    2987       54916 :                 error = xlog_bread(log, tail_blk, 1, hbp, &offset);
    2988       54916 :                 if (error)
    2989           0 :                         goto bread_err1;
    2990             : 
    2991       54916 :                 rhead = (xlog_rec_header_t *)offset;
    2992             : 
    2993             :                 /*
    2994             :                  * xfsprogs has a bug where record length is based on lsunit but
    2995             :                  * h_size (iclog size) is hardcoded to 32k. Now that we
    2996             :                  * unconditionally CRC verify the unmount record, this means the
    2997             :                  * log buffer can be too small for the record and cause an
    2998             :                  * overrun.
    2999             :                  *
    3000             :                  * Detect this condition here. Use lsunit for the buffer size as
    3001             :                  * long as this looks like the mkfs case. Otherwise, return an
    3002             :                  * error to avoid a buffer overrun.
    3003             :                  */
    3004       54916 :                 h_size = be32_to_cpu(rhead->h_size);
    3005       54916 :                 h_len = be32_to_cpu(rhead->h_len);
    3006       54916 :                 if (h_len > h_size && h_len <= log->l_mp->m_logbsize &&
    3007           0 :                     rhead->h_num_logops == cpu_to_be32(1)) {
    3008           0 :                         xfs_warn(log->l_mp,
    3009             :                 "invalid iclog size (%d bytes), using lsunit (%d bytes)",
    3010             :                                  h_size, log->l_mp->m_logbsize);
    3011           0 :                         h_size = log->l_mp->m_logbsize;
    3012             :                 }
    3013             : 
    3014       54916 :                 error = xlog_valid_rec_header(log, rhead, tail_blk, h_size);
    3015       54916 :                 if (error)
    3016           0 :                         goto bread_err1;
    3017             : 
    3018       54916 :                 hblks = xlog_logrec_hblks(log, rhead);
    3019       54916 :                 if (hblks != 1) {
    3020         796 :                         kmem_free(hbp);
    3021         796 :                         hbp = xlog_alloc_buffer(log, hblks);
    3022             :                 }
    3023             :         } else {
    3024           0 :                 ASSERT(log->l_sectBBsize == 1);
    3025           0 :                 hblks = 1;
    3026           0 :                 hbp = xlog_alloc_buffer(log, 1);
    3027           0 :                 h_size = XLOG_BIG_RECORD_BSIZE;
    3028             :         }
    3029             : 
    3030       54916 :         if (!hbp)
    3031             :                 return -ENOMEM;
    3032       54916 :         dbp = xlog_alloc_buffer(log, BTOBB(h_size));
    3033       54916 :         if (!dbp) {
    3034           0 :                 kmem_free(hbp);
    3035           0 :                 return -ENOMEM;
    3036             :         }
    3037             : 
    3038       54916 :         memset(rhash, 0, sizeof(rhash));
    3039       54916 :         if (tail_blk > head_blk) {
    3040             :                 /*
    3041             :                  * Perform recovery around the end of the physical log.
    3042             :                  * When the head is not on the same cycle number as the tail,
    3043             :                  * we can't do a sequential recovery.
    3044             :                  */
    3045      284494 :                 while (blk_no < log->l_logBBsize) {
    3046             :                         /*
    3047             :                          * Check for header wrapping around physical end-of-log
    3048             :                          */
    3049      282599 :                         offset = hbp;
    3050      282599 :                         split_hblks = 0;
    3051      282599 :                         wrapped_hblks = 0;
    3052      282599 :                         if (blk_no + hblks <= log->l_logBBsize) {
    3053             :                                 /* Read header in one read */
    3054      282599 :                                 error = xlog_bread(log, blk_no, hblks, hbp,
    3055             :                                                    &offset);
    3056      282599 :                                 if (error)
    3057           0 :                                         goto bread_err2;
    3058             :                         } else {
    3059             :                                 /* This LR is split across physical log end */
    3060           0 :                                 if (blk_no != log->l_logBBsize) {
    3061             :                                         /* some data before physical log end */
    3062           0 :                                         ASSERT(blk_no <= INT_MAX);
    3063           0 :                                         split_hblks = log->l_logBBsize - (int)blk_no;
    3064           0 :                                         ASSERT(split_hblks > 0);
    3065           0 :                                         error = xlog_bread(log, blk_no,
    3066             :                                                            split_hblks, hbp,
    3067             :                                                            &offset);
    3068           0 :                                         if (error)
    3069           0 :                                                 goto bread_err2;
    3070             :                                 }
    3071             : 
    3072             :                                 /*
    3073             :                                  * Note: this black magic still works with
    3074             :                                  * large sector sizes (non-512) only because:
    3075             :                                  * - we increased the buffer size originally
    3076             :                                  *   by 1 sector giving us enough extra space
    3077             :                                  *   for the second read;
    3078             :                                  * - the log start is guaranteed to be sector
    3079             :                                  *   aligned;
    3080             :                                  * - we read the log end (LR header start)
    3081             :                                  *   _first_, then the log start (LR header end)
    3082             :                                  *   - order is important.
    3083             :                                  */
    3084           0 :                                 wrapped_hblks = hblks - split_hblks;
    3085           0 :                                 error = xlog_bread_noalign(log, 0,
    3086             :                                                 wrapped_hblks,
    3087           0 :                                                 offset + BBTOB(split_hblks));
    3088           0 :                                 if (error)
    3089           0 :                                         goto bread_err2;
    3090             :                         }
    3091      282599 :                         rhead = (xlog_rec_header_t *)offset;
    3092      282599 :                         error = xlog_valid_rec_header(log, rhead,
    3093             :                                         split_hblks ? blk_no : 0, h_size);
    3094      282599 :                         if (error)
    3095           0 :                                 goto bread_err2;
    3096             : 
    3097      282599 :                         bblks = (int)BTOBB(be32_to_cpu(rhead->h_len));
    3098      282599 :                         blk_no += hblks;
    3099             : 
    3100             :                         /*
    3101             :                          * Read the log record data in multiple reads if it
    3102             :                          * wraps around the end of the log. Note that if the
    3103             :                          * header already wrapped, blk_no could point past the
    3104             :                          * end of the log. The record data is contiguous in
    3105             :                          * that case.
    3106             :                          */
    3107      282599 :                         if (blk_no + bblks <= log->l_logBBsize ||
    3108             :                             blk_no >= log->l_logBBsize) {
    3109      280956 :                                 rblk_no = xlog_wrap_logbno(log, blk_no);
    3110      280956 :                                 error = xlog_bread(log, rblk_no, bblks, dbp,
    3111             :                                                    &offset);
    3112      280956 :                                 if (error)
    3113           0 :                                         goto bread_err2;
    3114             :                         } else {
    3115             :                                 /* This log record is split across the
    3116             :                                  * physical end of log */
    3117        1643 :                                 offset = dbp;
    3118        1643 :                                 split_bblks = 0;
    3119        1643 :                                 if (blk_no != log->l_logBBsize) {
    3120             :                                         /* some data is before the physical
    3121             :                                          * end of log */
    3122        1643 :                                         ASSERT(!wrapped_hblks);
    3123        1643 :                                         ASSERT(blk_no <= INT_MAX);
    3124        1643 :                                         split_bblks =
    3125        1643 :                                                 log->l_logBBsize - (int)blk_no;
    3126        1643 :                                         ASSERT(split_bblks > 0);
    3127        1643 :                                         error = xlog_bread(log, blk_no,
    3128             :                                                         split_bblks, dbp,
    3129             :                                                         &offset);
    3130        1643 :                                         if (error)
    3131           0 :                                                 goto bread_err2;
    3132             :                                 }
    3133             : 
    3134             :                                 /*
    3135             :                                  * Note: this black magic still works with
    3136             :                                  * large sector sizes (non-512) only because:
    3137             :                                  * - we increased the buffer size originally
    3138             :                                  *   by 1 sector giving us enough extra space
    3139             :                                  *   for the second read;
    3140             :                                  * - the log start is guaranteed to be sector
    3141             :                                  *   aligned;
    3142             :                                  * - we read the log end (LR header start)
    3143             :                                  *   _first_, then the log start (LR header end)
    3144             :                                  *   - order is important.
    3145             :                                  */
    3146        1643 :                                 error = xlog_bread_noalign(log, 0,
    3147             :                                                 bblks - split_bblks,
    3148        1643 :                                                 offset + BBTOB(split_bblks));
    3149        1643 :                                 if (error)
    3150           0 :                                         goto bread_err2;
    3151             :                         }
    3152             : 
    3153      282599 :                         error = xlog_recover_process(log, rhash, rhead, offset,
    3154             :                                                      pass, &buffer_list);
    3155      282599 :                         if (error)
    3156           0 :                                 goto bread_err2;
    3157             : 
    3158             :                         blk_no += bblks;
    3159             :                         rhead_blk = blk_no;
    3160             :                 }
    3161             : 
    3162        1895 :                 ASSERT(blk_no >= log->l_logBBsize);
    3163        1895 :                 blk_no -= log->l_logBBsize;
    3164        1895 :                 rhead_blk = blk_no;
    3165             :         }
    3166             : 
    3167             :         /* read first part of physical log */
    3168     4537535 :         while (blk_no < head_blk) {
    3169     4482675 :                 error = xlog_bread(log, blk_no, hblks, hbp, &offset);
    3170     4482675 :                 if (error)
    3171           0 :                         goto bread_err2;
    3172             : 
    3173     4482675 :                 rhead = (xlog_rec_header_t *)offset;
    3174     4482675 :                 error = xlog_valid_rec_header(log, rhead, blk_no, h_size);
    3175     4482675 :                 if (error)
    3176           0 :                         goto bread_err2;
    3177             : 
    3178             :                 /* blocks in data section */
    3179     4482675 :                 bblks = (int)BTOBB(be32_to_cpu(rhead->h_len));
    3180     4482675 :                 error = xlog_bread(log, blk_no+hblks, bblks, dbp,
    3181             :                                    &offset);
    3182     4482675 :                 if (error)
    3183           0 :                         goto bread_err2;
    3184             : 
    3185     4482675 :                 error = xlog_recover_process(log, rhash, rhead, offset, pass,
    3186             :                                              &buffer_list);
    3187     4482675 :                 if (error)
    3188          56 :                         goto bread_err2;
    3189             : 
    3190     4482619 :                 blk_no += bblks + hblks;
    3191     4482619 :                 rhead_blk = blk_no;
    3192             :         }
    3193             : 
    3194       54860 :  bread_err2:
    3195       54916 :         kmem_free(dbp);
    3196       54916 :  bread_err1:
    3197       54916 :         kmem_free(hbp);
    3198             : 
    3199             :         /*
    3200             :          * Submit buffers that have been added from the last record processed,
    3201             :          * regardless of error status.
    3202             :          */
    3203       54916 :         if (!list_empty(&buffer_list))
    3204       12849 :                 error2 = xfs_buf_delwri_submit(&buffer_list);
    3205             : 
    3206       54916 :         if (error && first_bad)
    3207          56 :                 *first_bad = rhead_blk;
    3208             : 
    3209             :         /*
    3210             :          * Transactions are freed at commit time but transactions without commit
    3211             :          * records on disk are never committed. Free any that may be left in the
    3212             :          * hash table.
    3213             :          */
    3214      933572 :         for (i = 0; i < XLOG_RHASH_SIZE; i++) {
    3215      878656 :                 struct hlist_node       *tmp;
    3216      878656 :                 struct xlog_recover     *trans;
    3217             : 
    3218     1759340 :                 hlist_for_each_entry_safe(trans, tmp, &rhash[i], r_list)
    3219        2028 :                         xlog_recover_free_trans(trans);
    3220             :         }
    3221             : 
    3222       54916 :         return error ? error : error2;
    3223             : }
    3224             : 
    3225             : /*
    3226             :  * Do the recovery of the log.  We actually do this in two phases.
    3227             :  * The two passes are necessary in order to implement the function
    3228             :  * of cancelling a record written into the log.  The first pass
    3229             :  * determines those things which have been cancelled, and the
    3230             :  * second pass replays log items normally except for those which
    3231             :  * have been cancelled.  The handling of the replay and cancellations
    3232             :  * takes place in the log item type specific routines.
    3233             :  *
    3234             :  * The table of items which have cancel records in the log is allocated
    3235             :  * and freed at this level, since only here do we know when all of
    3236             :  * the log recovery has been completed.
    3237             :  */
    3238             : STATIC int
    3239       13723 : xlog_do_log_recovery(
    3240             :         struct xlog     *log,
    3241             :         xfs_daddr_t     head_blk,
    3242             :         xfs_daddr_t     tail_blk)
    3243             : {
    3244       13723 :         int             error;
    3245             : 
    3246       13723 :         ASSERT(head_blk != tail_blk);
    3247             : 
    3248             :         /*
    3249             :          * First do a pass to find all of the cancelled buf log items.
    3250             :          * Store them in the buf_cancel_table for use in the second pass.
    3251             :          */
    3252       13723 :         error = xlog_alloc_buf_cancel_table(log);
    3253       13723 :         if (error)
    3254             :                 return error;
    3255             : 
    3256       13723 :         error = xlog_do_recovery_pass(log, head_blk, tail_blk,
    3257             :                                       XLOG_RECOVER_PASS1, NULL);
    3258       13723 :         if (error != 0)
    3259           0 :                 goto out_cancel;
    3260             : 
    3261             :         /*
    3262             :          * Then do a second pass to actually recover the items in the log.
    3263             :          * When it is complete free the table of buf cancel items.
    3264             :          */
    3265       13723 :         error = xlog_do_recovery_pass(log, head_blk, tail_blk,
    3266             :                                       XLOG_RECOVER_PASS2, NULL);
    3267       13723 :         if (!error)
    3268       13723 :                 xlog_check_buf_cancel_table(log);
    3269           0 : out_cancel:
    3270       13723 :         xlog_free_buf_cancel_table(log);
    3271       13723 :         return error;
    3272             : }
    3273             : 
    3274             : /*
    3275             :  * Do the actual recovery
    3276             :  */
    3277             : STATIC int
    3278       13723 : xlog_do_recover(
    3279             :         struct xlog             *log,
    3280             :         xfs_daddr_t             head_blk,
    3281             :         xfs_daddr_t             tail_blk)
    3282             : {
    3283       13723 :         struct xfs_mount        *mp = log->l_mp;
    3284       13723 :         struct xfs_buf          *bp = mp->m_sb_bp;
    3285       13723 :         struct xfs_sb           *sbp = &mp->m_sb;
    3286       13723 :         int                     error;
    3287             : 
    3288       13723 :         trace_xfs_log_recover(log, head_blk, tail_blk);
    3289             : 
    3290             :         /*
    3291             :          * First replay the images in the log.
    3292             :          */
    3293       13723 :         error = xlog_do_log_recovery(log, head_blk, tail_blk);
    3294       13723 :         if (error)
    3295             :                 return error;
    3296             : 
    3297       27446 :         if (xlog_is_shutdown(log))
    3298             :                 return -EIO;
    3299             : 
    3300             :         /*
    3301             :          * We now update the tail_lsn since much of the recovery has completed
    3302             :          * and there may be space available to use.  If there were no extent
    3303             :          * or iunlinks, we can free up the entire log and set the tail_lsn to
    3304             :          * be the last_sync_lsn.  This was set in xlog_find_tail to be the
    3305             :          * lsn of the last known good LR on disk.  If there are extent frees
    3306             :          * or iunlinks they will have some entries in the AIL; so we look at
    3307             :          * the AIL to determine how to set the tail_lsn.
    3308             :          */
    3309       13723 :         xlog_assign_tail_lsn(mp);
    3310             : 
    3311             :         /*
    3312             :          * Now that we've finished replaying all buffer and inode updates,
    3313             :          * re-read the superblock and reverify it.
    3314             :          */
    3315       13723 :         xfs_buf_lock(bp);
    3316       13723 :         xfs_buf_hold(bp);
    3317       13723 :         error = _xfs_buf_read(bp, XBF_READ);
    3318       13723 :         if (error) {
    3319           0 :                 if (!xlog_is_shutdown(log)) {
    3320           0 :                         xfs_buf_ioerror_alert(bp, __this_address);
    3321           0 :                         ASSERT(0);
    3322             :                 }
    3323           0 :                 xfs_buf_relse(bp);
    3324           0 :                 return error;
    3325             :         }
    3326             : 
    3327             :         /* Convert superblock from on-disk format */
    3328       13723 :         xfs_sb_from_disk(sbp, bp->b_addr);
    3329       13723 :         xfs_buf_relse(bp);
    3330             : 
    3331             :         /* re-initialise in-core superblock and geometry structures */
    3332       13723 :         mp->m_features |= xfs_sb_version_to_features(sbp);
    3333       13723 :         xfs_reinit_percpu_counters(mp);
    3334       13723 :         error = xfs_initialize_perag(mp, sbp->sb_agcount, sbp->sb_dblocks,
    3335             :                         &mp->m_maxagi);
    3336       13723 :         if (error) {
    3337           0 :                 xfs_warn(mp, "Failed post-recovery per-ag init: %d", error);
    3338           0 :                 return error;
    3339             :         }
    3340       13723 :         mp->m_alloc_set_aside = xfs_alloc_set_aside(mp);
    3341             : 
    3342             :         /* Normal transactions can now occur */
    3343       13723 :         clear_bit(XLOG_ACTIVE_RECOVERY, &log->l_opstate);
    3344       13723 :         return 0;
    3345             : }
    3346             : 
    3347             : /*
    3348             :  * Perform recovery and re-initialize some log variables in xlog_find_tail.
    3349             :  *
    3350             :  * Return error or zero.
    3351             :  */
    3352             : int
    3353       59235 : xlog_recover(
    3354             :         struct xlog     *log)
    3355             : {
    3356       59235 :         xfs_daddr_t     head_blk, tail_blk;
    3357       59235 :         int             error;
    3358             : 
    3359             :         /* find the tail of the log */
    3360       59235 :         error = xlog_find_tail(log, &head_blk, &tail_blk);
    3361       59235 :         if (error)
    3362             :                 return error;
    3363             : 
    3364             :         /*
    3365             :          * The superblock was read before the log was available and thus the LSN
    3366             :          * could not be verified. Check the superblock LSN against the current
    3367             :          * LSN now that it's known.
    3368             :          */
    3369      118235 :         if (xfs_has_crc(log->l_mp) &&
    3370       59020 :             !xfs_log_check_lsn(log->l_mp, log->l_mp->m_sb.sb_lsn))
    3371             :                 return -EINVAL;
    3372             : 
    3373       59204 :         if (tail_blk != head_blk) {
    3374             :                 /* There used to be a comment here:
    3375             :                  *
    3376             :                  * disallow recovery on read-only mounts.  note -- mount
    3377             :                  * checks for ENOSPC and turns it into an intelligent
    3378             :                  * error message.
    3379             :                  * ...but this is no longer true.  Now, unless you specify
    3380             :                  * NORECOVERY (in which case this function would never be
    3381             :                  * called), we just go ahead and recover.  We do this all
    3382             :                  * under the vfs layer, so we can get away with it unless
    3383             :                  * the device itself is read-only, in which case we fail.
    3384             :                  */
    3385       13734 :                 if ((error = xfs_dev_is_read_only(log->l_mp, "recovery"))) {
    3386             :                         return error;
    3387             :                 }
    3388             : 
    3389             :                 /*
    3390             :                  * Version 5 superblock log feature mask validation. We know the
    3391             :                  * log is dirty so check if there are any unknown log features
    3392             :                  * in what we need to recover. If there are unknown features
    3393             :                  * (e.g. unsupported transactions, then simply reject the
    3394             :                  * attempt at recovery before touching anything.
    3395             :                  */
    3396       13723 :                 if (xfs_sb_is_v5(&log->l_mp->m_sb) &&
    3397             :                     xfs_sb_has_incompat_log_feature(&log->l_mp->m_sb,
    3398             :                                         XFS_SB_FEAT_INCOMPAT_LOG_UNKNOWN)) {
    3399           0 :                         xfs_warn(log->l_mp,
    3400             : "Superblock has unknown incompatible log features (0x%x) enabled.",
    3401             :                                 (log->l_mp->m_sb.sb_features_log_incompat &
    3402             :                                         XFS_SB_FEAT_INCOMPAT_LOG_UNKNOWN));
    3403           0 :                         xfs_warn(log->l_mp,
    3404             : "The log can not be fully and/or safely recovered by this kernel.");
    3405           0 :                         xfs_warn(log->l_mp,
    3406             : "Please recover the log on a kernel that supports the unknown features.");
    3407           0 :                         return -EINVAL;
    3408             :                 }
    3409             : 
    3410             :                 /*
    3411             :                  * Delay log recovery if the debug hook is set. This is debug
    3412             :                  * instrumentation to coordinate simulation of I/O failures with
    3413             :                  * log recovery.
    3414             :                  */
    3415       13723 :                 if (xfs_globals.log_recovery_delay) {
    3416          22 :                         xfs_notice(log->l_mp,
    3417             :                                 "Delaying log recovery for %d seconds.",
    3418             :                                 xfs_globals.log_recovery_delay);
    3419          22 :                         msleep(xfs_globals.log_recovery_delay * 1000);
    3420             :                 }
    3421             : 
    3422       15349 :                 xfs_notice(log->l_mp, "Starting recovery (logdev: %s)",
    3423             :                                 log->l_mp->m_logname ? log->l_mp->m_logname
    3424             :                                                      : "internal");
    3425             : 
    3426       13723 :                 error = xlog_do_recover(log, head_blk, tail_blk);
    3427       13723 :                 set_bit(XLOG_RECOVERY_NEEDED, &log->l_opstate);
    3428             :         }
    3429             :         return error;
    3430             : }
    3431             : 
    3432             : /*
    3433             :  * In the first part of recovery we replay inodes and buffers and build up the
    3434             :  * list of intents which need to be processed. Here we process the intents and
    3435             :  * clean up the on disk unlinked inode lists. This is separated from the first
    3436             :  * part of recovery so that the root and real-time bitmap inodes can be read in
    3437             :  * from disk in between the two stages.  This is necessary so that we can free
    3438             :  * space in the real-time portion of the file system.
    3439             :  */
    3440             : int
    3441       13723 : xlog_recover_finish(
    3442             :         struct xlog     *log)
    3443             : {
    3444       13723 :         int     error;
    3445             : 
    3446       13723 :         error = xlog_recover_process_intents(log);
    3447             :         /*
    3448             :          * Sync the log to get all the intents that have done item out of
    3449             :          * the AIL.  This isn't absolutely necessary, but it helps in case
    3450             :          * the unlink transactions would have problems pushing the intents
    3451             :          * out of the way.
    3452             :          */
    3453       13723 :         xfs_log_force(log->l_mp, XFS_LOG_SYNC);
    3454       13723 :         if (error) {
    3455             :                 /*
    3456             :                  * Cancel all the unprocessed intent items now so that we don't
    3457             :                  * leave them pinned in the AIL.  This can cause the AIL to
    3458             :                  * livelock on the pinned item if anyone tries to push the AIL
    3459             :                  * (inode reclaim does this) before we get around to
    3460             :                  * xfs_log_mount_cancel.
    3461             :                  */
    3462           6 :                 xlog_recover_cancel_intents(log);
    3463           6 :                 xfs_alert(log->l_mp, "Failed to recover intents");
    3464           6 :                 xlog_force_shutdown(log, SHUTDOWN_LOG_IO_ERROR);
    3465           6 :                 return error;
    3466             :         }
    3467             : 
    3468             :         /*
    3469             :          * Now that we've recovered the log and all the intents, we can clear
    3470             :          * the log incompat feature bits in the superblock because there's no
    3471             :          * longer anything to protect.  We rely on the AIL push to write out the
    3472             :          * updated superblock after everything else.
    3473             :          */
    3474       13717 :         if (xfs_clear_incompat_log_features(log->l_mp)) {
    3475         344 :                 error = xfs_sync_sb(log->l_mp, false);
    3476         344 :                 if (error < 0) {
    3477           0 :                         xfs_alert(log->l_mp,
    3478             :         "Failed to clear log incompat features on recovery");
    3479           0 :                         return error;
    3480             :                 }
    3481             :         }
    3482             : 
    3483       13717 :         xlog_recover_process_iunlinks(log);
    3484             : 
    3485             :         /*
    3486             :          * Recover any CoW staging blocks that are still referenced by the
    3487             :          * ondisk refcount metadata.  During mount there cannot be any live
    3488             :          * staging extents as we have not permitted any user modifications.
    3489             :          * Therefore, it is safe to free them all right now, even on a
    3490             :          * read-only mount.
    3491             :          */
    3492       13717 :         error = xfs_reflink_recover_cow(log->l_mp);
    3493       13717 :         if (error) {
    3494          22 :                 xfs_alert(log->l_mp,
    3495             :         "Failed to recover leftover CoW staging extents, err %d.",
    3496             :                                 error);
    3497             :                 /*
    3498             :                  * If we get an error here, make sure the log is shut down
    3499             :                  * but return zero so that any log items committed since the
    3500             :                  * end of intents processing can be pushed through the CIL
    3501             :                  * and AIL.
    3502             :                  */
    3503          22 :                 xlog_force_shutdown(log, SHUTDOWN_LOG_IO_ERROR);
    3504             :         }
    3505             : 
    3506             :         return 0;
    3507             : }
    3508             : 
    3509             : void
    3510         190 : xlog_recover_cancel(
    3511             :         struct xlog     *log)
    3512             : {
    3513         380 :         if (xlog_recovery_needed(log))
    3514           0 :                 xlog_recover_cancel_intents(log);
    3515         190 : }
    3516             : 

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