From patchwork Wed Jul 27 10:56:19 2011 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Anand Avati X-Patchwork-Id: 1011332 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by demeter2.kernel.org (8.14.4/8.14.4) with ESMTP id p6RAumom014717 for ; Wed, 27 Jul 2011 10:56:48 GMT Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754024Ab1G0K4r (ORCPT ); Wed, 27 Jul 2011 06:56:47 -0400 Received: from hub024-nj-5.exch024.serverdata.net ([206.225.165.120]:38414 "EHLO HUB024-nj-5.exch024.serverdata.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753555Ab1G0K4q (ORCPT ); Wed, 27 Jul 2011 06:56:46 -0400 Received: from localhost.localdomain (184.107.76.11) by east.exch024.serverdata.net (10.240.10.43) with Microsoft SMTP Server (TLS) id 14.1.289.1; Wed, 27 Jul 2011 03:56:45 -0700 From: Anand Avati To: CC: , , , Anand Avati Subject: [PATCH v2 2/2] fuse: permit O_DIRECT flag in open() Date: Wed, 27 Jul 2011 03:56:19 -0700 Message-ID: <1311764179-20326-2-git-send-email-avati@gluster.com> X-Mailer: git-send-email 1.7.4.1 In-Reply-To: <1311764179-20326-1-git-send-email-avati@gluster.com> References: <1311764179-20326-1-git-send-email-avati@gluster.com> MIME-Version: 1.0 Sender: linux-nfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-nfs@vger.kernel.org X-Greylist: IP, sender and recipient auto-whitelisted, not delayed by milter-greylist-4.2.6 (demeter2.kernel.org [140.211.167.43]); Wed, 27 Jul 2011 10:56:48 +0000 (UTC) FUSE currently disallows O_DIRECT flag in open(). It is tricky dealing with setting/unsetting of O_DIRECT flag on an open file. There are applications (primarily VMs and databases) which open files with O_DIRECT flag. These applications do not work on FUSE due to this limitation. The approach with this patch is to permit opens with O_DIRECT, but instead disable setting/unsetting of the O_DIRECT flag no matter how the file was opened. This limitation is for more practical than disallowing O_DIRECT altogether. Signed-off-by: Anand Avati --- fs/fuse/file.c | 36 ++++++++++++++++++++++++++++++++---- 1 files changed, 32 insertions(+), 4 deletions(-) diff --git a/fs/fuse/file.c b/fs/fuse/file.c index 82a6646..355c30f 100644 --- a/fs/fuse/file.c +++ b/fs/fuse/file.c @@ -154,6 +154,27 @@ int fuse_do_open(struct fuse_conn *fc, u64 nodeid, struct file *file, return err; } + if (file->f_flags & O_DIRECT) { + if (!(outarg.open_flags & FOPEN_DIRECT_IO)) { + /* filesystem process did not acknowledge the O_DIRECT + flag with FOPEN_DIRECT_IO bit in ourarg. Hence + we fail the open(). + + Notify the filesystem process about the failed + open with fuse_sync_release right here itself as + file->private_data is not yet set up for release + notification. + */ + fuse_sync_release(ff, file->f_flags); + return -EINVAL; + } + + /* make VFS believe we don't support O_DIRECT till we + implement a_ops->direct_IO + */ + file->f_flags &= ~O_DIRECT; + } + if (isdir) outarg.open_flags &= ~FOPEN_DIRECT_IO; @@ -193,10 +214,6 @@ int fuse_open_common(struct inode *inode, struct file *file, bool isdir) struct fuse_conn *fc = get_fuse_conn(inode); int err; - /* VFS checks this, but only _after_ ->open() */ - if (file->f_flags & O_DIRECT) - return -EINVAL; - err = generic_file_open(inode, file); if (err) return err; @@ -2132,6 +2149,15 @@ int fuse_notify_poll_wakeup(struct fuse_conn *fc, return 0; } + +static int fuse_check_flags(struct file *filp, int flags) +{ + if ((filp->f_flags ^ flags) & O_DIRECT) + return -EINVAL; + return 0; +} + + static const struct file_operations fuse_file_operations = { .llseek = fuse_file_llseek, .read = do_sync_read, @@ -2149,6 +2175,7 @@ static const struct file_operations fuse_file_operations = { .unlocked_ioctl = fuse_file_ioctl, .compat_ioctl = fuse_file_compat_ioctl, .poll = fuse_file_poll, + .check_flags = fuse_check_flags, }; static const struct file_operations fuse_direct_io_file_operations = { @@ -2165,6 +2192,7 @@ static const struct file_operations fuse_direct_io_file_operations = { .unlocked_ioctl = fuse_file_ioctl, .compat_ioctl = fuse_file_compat_ioctl, .poll = fuse_file_poll, + .check_flags = fuse_check_flags, /* no splice_read */ };