• Darrick J. Wong's avatar
    iomap: report collisions between directio and buffered writes to userspace · 5a9d929d
    Darrick J. Wong authored
    If two programs simultaneously try to write to the same part of a file
    via direct IO and buffered IO, there's a chance that the post-diowrite
    pagecache invalidation will fail on the dirty page.  When this happens,
    the dio write succeeded, which means that the page cache is no longer
    coherent with the disk!
    
    Programs are not supposed to mix IO types and this is a clear case of
    data corruption, so store an EIO which will be reflected to userspace
    during the next fsync.  Replace the WARN_ON with a ratelimited pr_crit
    so that the developers have /some/ kind of breadcrumb to track down the
    offending program(s) and file(s) involved.
    Signed-off-by: default avatarDarrick J. Wong <darrick.wong@oracle.com>
    Reviewed-by: default avatarLiu Bo <bo.li.liu@oracle.com>
    5a9d929d
direct-io.c 41 KB