• Dave Chinner's avatar
    xfs: make AIL target updates and compares 32bit safe. · fe0da767
    Dave Chinner authored
    The recent conversion of the xfsaild functionality to a work queue
    introduced a hard-to-hit log space grant hang. One of the problems
    noticed was that updates of the push target are not 32 bit safe as
    the target is a 64 bit value.
    
    We cannot copy a 64 bit LSN without the possibility of corrupting
    the result when racing with another updating thread. We have
    function to do this update safely without needing to care about
    32/64 bit issues - xfs_trans_ail_copy_lsn() - so use that when
    updating the AIL push target.
    
    Also move the reading of the target in the push work inside the AIL
    lock, and use XFS_LSN_CMP() for the unlocked comparison during work
    termination to close read holes as well.
    Signed-off-by: default avatarDave Chinner <david@fromorbit.com>
    Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
    Reviewed-by: default avatarAlex Elder <aelder@sgi.com>
    
    (cherry picked from commit fd5670f2)
    fe0da767
xfs_trans_ail.c 21.6 KB