From: "Darrick J. Wong" darrick.wong@oracle.com
commit 1fdeaea4d92c69fb9f871a787af6ad00f32eeea7 upstream.
Dave Chinner noticed that xfs_file_dio_aio_write returns EAGAIN without dropping the IOLOCK when its deciding not to wait, which means that we leak the IOLOCK there. Since we now make unaligned directio always wait, we have the opportunity to bail out before trying to take the lock, which should reduce the overhead of this never-gonna-work case considerably while also solving the dropped lock problem.
Reported-by: Dave Chinner david@fromorbit.com Signed-off-by: Darrick J. Wong darrick.wong@oracle.com Reviewed-by: Brian Foster bfoster@redhat.com Reviewed-by: Dave Chinner dchinner@redhat.com Reviewed-by: Christoph Hellwig hch@lst.de Signed-off-by: Luis Chamberlain mcgrof@kernel.org --- fs/xfs/xfs_file.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c index 10f75965243c..259549698ba7 100644 --- a/fs/xfs/xfs_file.c +++ b/fs/xfs/xfs_file.c @@ -517,6 +517,9 @@ xfs_file_dio_aio_write( }
if (iocb->ki_flags & IOCB_NOWAIT) { + /* unaligned dio always waits, bail */ + if (unaligned_io) + return -EAGAIN; if (!xfs_ilock_nowait(ip, iolock)) return -EAGAIN; } else { @@ -536,9 +539,6 @@ xfs_file_dio_aio_write( * xfs_file_aio_write_checks() for other reasons. */ if (unaligned_io) { - /* unaligned dio always waits, bail */ - if (iocb->ki_flags & IOCB_NOWAIT) - return -EAGAIN; inode_dio_wait(inode); } else if (iolock == XFS_IOLOCK_EXCL) { xfs_ilock_demote(ip, XFS_IOLOCK_EXCL);