• Carlos Maiolino's avatar
    xfs: Properly retry failed inode items in case of error during buffer writeback · d3a304b6
    Carlos Maiolino authored
    When a buffer has been failed during writeback, the inode items into it
    are kept flush locked, and are never resubmitted due the flush lock, so,
    if any buffer fails to be written, the items in AIL are never written to
    disk and never unlocked.
    
    This causes unmount operation to hang due these items flush locked in AIL,
    but this also causes the items in AIL to never be written back, even when
    the IO device comes back to normal.
    
    I've been testing this patch with a DM-thin device, creating a
    filesystem larger than the real device.
    
    When writing enough data to fill the DM-thin device, XFS receives ENOSPC
    errors from the device, and keep spinning on xfsaild (when 'retry
    forever' configuration is set).
    
    At this point, the filesystem can not be unmounted because of the flush locked
    items in AIL, but worse, the items in AIL are never retried at all
    (once xfs_inode_item_push() will skip the items that are flush locked),
    even if the underlying DM-thin device is expanded to the proper size.
    
    This patch fixes both cases, retrying any item that has been failed
    previously, using the infra-structure provided by the previous patch.
    Reviewed-by: 's avatarBrian Foster <bfoster@redhat.com>
    Signed-off-by: 's avatarCarlos Maiolino <cmaiolino@redhat.com>
    Reviewed-by: 's avatarDarrick J. Wong <darrick.wong@oracle.com>
    Signed-off-by: 's avatarDarrick J. Wong <darrick.wong@oracle.com>
    d3a304b6