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    Subject[PATCH] ext3: wait on all pending commits in ext3_sync_fs
    Hi Eric,   This patch fixes the problem for me, and
    seems to put the buffers on the dirty list at the
    place where they are put on the list during the working
    case. Despite having rooted around in the innards of
    ext3 for the last few days, I cannot say that I have
    any sense of whether this patch will cause problems
    elsewhere or even if this is the best place to

    I post the complete patch not because I think it
    should be committed as is, but rather to try
    to explain the logic that brought it about. At the
    very least, this should be reviewed by the experts
    here to make sure there is no collateral damage.


    In ext3_sync_fs, we only wait for a commit to
    finish if we started it, but there may be one
    already in progress which will not be synced.

    In the case of a data=ordered umount with pending long
    symlinks which are delayed due to a long list
    of other I/O on the backing block device, this
    causes the buffer associated with the long symlinks
    to not be moved to the inode dirty list in the second
    phase of fsync_super. Then, before they can be dirtied
    again, kjournald exits, seeing the UMOUNT flag and the
    dirty pages are never written to the backing block device,
    causing long symlink corruption and exposing new or
    previously freed block data to userspace.

    This can be reproduced with a script created
    by Eric Sandeen <>:


    umount /mnt/test2
    mount /dev/sdb4 /mnt/test2
    rm -f /mnt/test2/*
    dd if=/dev/zero of=/mnt/test2/bigfile bs=1M count=512
    ln -s
    umount /mnt/test2
    mount /dev/sdb4 /mnt/test2
    ls /mnt/test2/
    umount /mnt/test2

    To ensure all commits are synced, we flush
    all journal commits now when sync_fs'ing ext3.

    Signed-off-by: Arthur Jones <>
    fs/ext3/super.c | 8 +++++++-
    1 files changed, 7 insertions(+), 1 deletions(-)

    diff --git a/fs/ext3/super.c b/fs/ext3/super.c
    index 18eaa78..053659a 100644
    --- a/fs/ext3/super.c
    +++ b/fs/ext3/super.c
    @@ -2392,7 +2392,13 @@ static int ext3_sync_fs(struct super_block *sb, int wait)
    if (journal_start_commit(EXT3_SB(sb)->s_journal, &target)) {
    if (wait)
    log_wait_commit(EXT3_SB(sb)->s_journal, target);
    - }
    + } else if (wait)
    + /*
    + * We may have a commit in progress, clear it out
    + * before we go on...
    + */
    + ext3_force_commit(sb);
    return 0;


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      Last update: 2008-11-03 19:47    [W:0.026 / U:28.648 seconds]
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