• David Chinner's avatar
    [XFS] Prevent a deadlock when xfslogd unpins inodes. · 4c60658e
    David Chinner authored
    The previous fixes for the use after free in xfs_iunpin left a nasty log
    deadlock when xfslogd unpinned the inode and dropped the last reference to
    the inode. the ->clear_inode() method can issue transactions, and if the
    log was full, the transaction could push on the log and get stuck trying
    to push the inode it was currently unpinning.
    
    To fix this, we provide xfs_iunpin a guarantee that it will always have a
    valid xfs_inode <-> linux inode link or a particular flag will be set on
    the inode. We then use log forces during lookup to ensure transactions are
    completed before we recycle the inode. This ensures that xfs_iunpin will
    never use the linux inode after it is being freed, and any lookup on an
    inode on the reclaim list will wait until it is safe to attach a new linux
    inode to the xfs inode.
    
    SGI-PV: 956832
    SGI-Modid: xfs-linux-melb:xfs-kern:27359a
    Signed-off-by: default avatarDavid Chinner <dgc@sgi.com>
    Signed-off-by: default avatarShailendra Tripathi <stripathi@agami.com>
    Signed-off-by: default avatarTakenori Nagano <t-nagano@ah.jp.nec.com>
    Signed-off-by: default avatarTim Shimmin <tes@sgi.com>
    4c60658e
xfs_vnodeops.c 115 KB