src/patches/suse-2.6.27.25/patches.fixes/ocfs2-fix-regression-in-ocfs2_read_blocks_sync.patch

   1 From: Mark Fasheh <mfasheh@suse.com>
   2 Date: Fri, 21 Nov 2008 14:06:55 -0800
   3 Subject: ocfs2: fix regression in ocfs2_read_blocks_sync()
   4
   5 We're panicing in ocfs2_read_blocks_sync() if a jbd-managed buffer is seen.
   6 At first glance, this seems ok but in reality it can happen. My test case
   7 was to just run 'exorcist'. A struct inode is being pushed out of memory but
   8 is then re-read at a later time, before the buffer has been checkpointed by
   9 jbd. This causes a BUG to be hit in ocfs2_read_blocks_sync().
  10
  11 Reviewed-by: Joel Becker <joel.becker@oracle.com>
  12 Signed-off-by: Mark Fasheh <mfasheh@suse.com>
  13 ---
  14  fs/ocfs2/buffer_head_io.c |   15 ++++-----------
  15  1 files changed, 4 insertions(+), 11 deletions(-)
  16
  17 Index: linux-2.6.27-ocfs2/fs/ocfs2/buffer_head_io.c
  18 ===================================================================
  19 --- linux-2.6.27-ocfs2.orig/fs/ocfs2/buffer_head_io.c
  20 +++ linux-2.6.27-ocfs2/fs/ocfs2/buffer_head_io.c
  21 @@ -112,7 +112,7 @@ int ocfs2_read_blocks_sync(struct ocfs2_
  22                 bh = bhs[i];
  23
  24                 if (buffer_jbd(bh)) {
  25 -                       mlog(ML_ERROR,
  26 +                       mlog(ML_BH_IO,
  27                              "trying to sync read a jbd "
  28                              "managed bh (blocknr = %llu), skipping\n",
  29                              (unsigned long long)bh->b_blocknr);
  30 @@ -147,15 +147,10 @@ int ocfs2_read_blocks_sync(struct ocfs2_
  31         for (i = nr; i > 0; i--) {
  32                 bh = bhs[i - 1];
  33
  34 -               if (buffer_jbd(bh)) {
  35 -                       mlog(ML_ERROR,
  36 -                            "the journal got the buffer while it was "
  37 -                            "locked for io! (blocknr = %llu)\n",
  38 -                            (unsigned long long)bh->b_blocknr);
  39 -                       BUG();
  40 -               }
  41 +               /* No need to wait on the buffer if it's managed by JBD. */
  42 +               if (!buffer_jbd(bh))
  43 +                       wait_on_buffer(bh);
  44
  45 -               wait_on_buffer(bh);
  46                 if (!buffer_uptodate(bh)) {
  47                         /* Status won't be cleared from here on out,
  48                          * so we can safely record this and loop back
  49 @@ -251,8 +246,6 @@ int ocfs2_read_blocks(struct inode *inod
  50                         ignore_cache = 1;
  51                 }
  52
  53 -               /* XXX: Can we ever get this and *not* have the cached
  54 -                * flag set? */
  55                 if (buffer_jbd(bh)) {
  56                         if (ignore_cache)
  57                                 mlog(ML_BH_IO, "trying to sync read a jbd "