tree d79456d053427728ce56a66424427574294bce5b
parent d36fd19d3f4c58a0a93e0588aef4eb5433c1364d
author Darrick J. Wong <darrick.wong@oracle.com> 1555516176 -0700
committer Luis Chamberlain <mcgrof@kernel.org> 1563489056 +0000

xfs: abort unaligned nowait directio early

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>