• Dave Chinner's avatar
    xfs: Ensure inode allocation buffers are fully replayed · ccf7c23f
    Dave Chinner authored
    With delayed logging, we can get inode allocation buffers in the
    same transaction inode unlink buffers. We don't currently mark inode
    allocation buffers in the log, so inode unlink buffers take
    precedence over allocation buffers.
    
    The result is that when they are combined into the same checkpoint,
    only the unlinked inode chain fields are replayed, resulting in
    uninitialised inode buffers being detected when the next inode
    modification is replayed.
    
    To fix this, we need to ensure that we do not set the inode buffer
    flag in the buffer log item format flags if the inode allocation has
    not already hit the log. To avoid requiring a change to log
    recovery, we really need to make this a modification that relies
    only on in-memory sate.
    
    We can do this by checking during buffer log formatting (while the
    CIL cannot be flushed) if we are still in the same sequence when we
    commit the unlink transaction as the inode allocation transaction.
    If we are, then we do not add the inode buffer flag to the buffer
    log format item flags. This means the entire buffer will be
    replayed, not just the unlinked fields. We do this while
    CIL flusheѕ are locked out to ensure that we don't race with the
    sequence numbers changing and hence fail to put the inode buffer
    flag in the buffer format flags when we really need to.
    Signed-off-by: default avatarDave Chinner <dchinner@redhat.com>
    Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
    Signed-off-by: default avatarAlex Elder <aelder@sgi.com>
    ccf7c23f
xfs_log_cil.c 21.4 KB