• Junichi Nomura's avatar
    mm/filemap.c: make global sync not clear error status of individual inodes · aa750fd7
    Junichi Nomura authored
    filemap_fdatawait() is a function to wait for on-going writeback to
    complete but also consume and clear error status of the mapping set during
    The latter functionality is critical for applications to detect writeback
    error with system calls like fsync(2)/fdatasync(2).
    However filemap_fdatawait() is also used by sync(2) or FIFREEZE ioctl,
    which don't check error status of individual mappings.
    As a result, fsync() may not be able to detect writeback error if events
    happen in the following order:
       Application                    System admin
       write data on page cache
                                      Run sync command
                                      writeback completes with error
                                      filemap_fdatawait() clears error
       fsync returns success
       (but the data is not on disk)
    This patch adds filemap_fdatawait_keep_errors() for call sites where
    writeback error is not handled so that they don't clear error status.
    Signed-off-by: default avatarJun'ichi Nomura <j-nomura@ce.jp.nec.com>
    Acked-by: default avatarAndi Kleen <ak@linux.intel.com>
    Reviewed-by: default avatarTejun Heo <tj@kernel.org>
    Cc: Fengguang Wu <fengguang.wu@gmail.com>
    Cc: Dave Chinner <david@fromorbit.com>
    Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
    Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
sync.c 9.9 KB