From patchwork Tue Nov 20 07:51:15 2012 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Subject: [8/9] filemap: don't call generic_write_sync for -EIOCBQUEUED Date: Mon, 19 Nov 2012 21:51:15 -0000 From: Darrick J. Wong X-Patchwork-Id: 200249 Message-Id: <20121120075114.25270.24389.stgit@blackbox.djwong.org> To: axboe@kernel.dk, tytso@mit.edu, david@fromorbit.com, jmoyer@redhat.com, bpm@sgi.com, viro@zeniv.linux.org.uk, jack@suse.cz Cc: linux-fsdevel@vger.kernel.org, hch@infradead.org, linux-ext4@vger.kernel.org, linux-kernel@vger.kernel.org, xfs@oss.sgi.com Hi, As it stands, generic_file_aio_write will call into generic_write_sync when -EIOCBQUEUED is returned from __generic_file_aio_write. EIOCBQUEUED indicates that an I/O was submitted but NOT completed. Thus, we will flush the disk cache, potentially before the write(s) even make it to the disk! Up until now, this has been the best we could do, as file systems didn't bother to flush the disk cache after an O_SYNC AIO+DIO write. After applying the prior two patches to xfs and ext4, at least the major two file systems do the right thing. So, let's go ahead and fix this backwards logic. From: Jeff Moyer Signed-off-by: Jeff Moyer --- mm/filemap.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html diff --git a/mm/filemap.c b/mm/filemap.c index 83efee7..8e14c10 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -2532,7 +2532,7 @@ ssize_t generic_file_aio_write(struct kiocb *iocb, const struct iovec *iov, ret = __generic_file_aio_write(iocb, iov, nr_segs, &iocb->ki_pos); mutex_unlock(&inode->i_mutex); - if (ret > 0 || ret == -EIOCBQUEUED) { + if (ret > 0) { ssize_t err; err = generic_write_sync(file, pos, ret);