tree a5f6ef95a01e38caa3dc1e50071d5baa78426a3f
parent b745fafaf70c0a98a2e1e7ac8cb14542889ceb0e
author Goldwyn Rodrigues <rgoldwyn@suse.com> 1497960344 -0500
committer Jens Axboe <axboe@kernel.dk> 1497964323 -0600

fs: return if direct I/O will trigger writeback

Find out if the I/O will trigger a wait due to writeback. If yes,
return -EAGAIN.

Return -EINVAL for buffered AIO: there are multiple causes of
delay such as page locks, dirty throttling logic, page loading
from disk etc. which cannot be taken care of.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>