From: Jeff Moyer Subject: [PATCH 3/3] filemap: don't call generic_write_sync for -EIOCBQUEUED Date: Fri, 27 Jan 2012 16:15:49 -0500 Message-ID: <1327698949-12616-4-git-send-email-jmoyer@redhat.com> References: <1327698949-12616-1-git-send-email-jmoyer@redhat.com> Cc: Jeff Moyer To: linux-ext4@vger.kernel.org, xfs@oss.sgi.com, linux-fsdevel@vger.kernel.org Return-path: Received: from mx1.redhat.com ([209.132.183.28]:33570 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753072Ab2A0VP4 (ORCPT ); Fri, 27 Jan 2012 16:15:56 -0500 In-Reply-To: <1327698949-12616-1-git-send-email-jmoyer@redhat.com> Sender: linux-ext4-owner@vger.kernel.org List-ID: 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. Signed-off-by: Jeff Moyer --- mm/filemap.c | 2 +- 1 files changed, 1 insertions(+), 1 deletions(-) diff --git a/mm/filemap.c b/mm/filemap.c index c4ee2e9..004442f 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -2634,7 +2634,7 @@ 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); -- 1.7.1