From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: with ECARTIS (v1.0.0; list xfs); Thu, 22 May 2008 01:48:43 -0700 (PDT) Received: from cuda.sgi.com (cuda1.sgi.com [192.48.168.28]) by oss.sgi.com (8.12.11.20060308/8.12.11/SuSE Linux 0.7) with ESMTP id m4M8meqn008830 for ; Thu, 22 May 2008 01:48:41 -0700 Received: from tyo201.gate.nec.co.jp (localhost [127.0.0.1]) by cuda.sgi.com (Spam Firewall) with ESMTP id 1616ABC1058 for ; Thu, 22 May 2008 01:49:28 -0700 (PDT) Received: from tyo201.gate.nec.co.jp (TYO201.gate.nec.co.jp [202.32.8.193]) by cuda.sgi.com with ESMTP id oWRKH2xphTe8O5Ey for ; Thu, 22 May 2008 01:49:28 -0700 (PDT) Subject: [RFC PATCH 0/3] freeze feature ver 1.4 Message-Id: <20080522174924t-sato@mail.jp.nec.com> Mime-Version: 1.0 From: Takashi Sato Date: Thu, 22 May 2008 17:49:24 +0900 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: xfs-bounce@oss.sgi.com Errors-to: xfs-bounce@oss.sgi.com List-Id: xfs To: "linux-ext4@vger.kernel.org" , "xfs@oss.sgi.com" , "dm-devel@redhat.com" , "linux-fsdevel@vger.kernel.org" Cc: "linux-kernel@vger.kernel.org" Hi, The freeze feature can suspend accesses to the filesystem keeping the filesystem's consistency. We can take the consistent backup with it cooperating with the backup software. I've modified [PATCH 1/3] to set the suitable error number (EOPNOTSUPP) in case the filesystem doesn't support the freeze feature. This was pointed out by Andreas Dilger. In addition, the patches are re-based from linux-2.6.26-rc2 to linux-2.6.26-rc3. The patch-set consists of the following three patches. [PATCH 1/3] Implement generic freeze feature I have modified to set the suitable error number (EOPNOTSUPP) in case the filesystem doesn't support the freeze feature. The ioctls for the generic freeze feature are below. o Freeze the filesystem int ioctl(int fd, int FIFREEZE, arg) fd: The file descriptor of the mountpoint FIFREEZE: request code for the freeze arg: Ignored Return value: 0 if the operation succeeds. Otherwise, -1 o Unfreeze the filesystem int ioctl(int fd, int FITHAW, arg) fd: The file descriptor of the mountpoint FITHAW: request code for unfreeze arg: Ignored Return value: 0 if the operation succeeds. Otherwise, -1 [PATCH 2/3] Remove XFS specific ioctl interfaces for freeze feature It removes XFS specific ioctl interfaces and request codes for freeze feature. This patch has been supplied by David Chinner. [PATCH 3/3] Add timeout feature The timeout feature is added to freeze ioctl. And new ioctl to reset the timeout period is added. o Freeze the filesystem int ioctl(int fd, int FIFREEZE, long *timeval) fd: The file descriptor of the mountpoint FIFREEZE: request code for the freeze timeval: the timeout period in seconds If it's 0 or 1, the timeout isn't set. This special case of "1" is implemented to keep the compatibility with XFS applications. Return value: 0 if the operation succeeds. Otherwise, -1 o Reset the timeout period This is useful for the application to set the timeval more accurately. For example, the freezer resets the timeval to 10 seconds every 5 seconds. In this approach, even if the freezer causes a deadlock by accessing the frozen filesystem, it will be solved by the timeout in 10 seconds and the freezer can recognize that at the next reset of timeval. int ioctl(int fd, int FIFREEZE_RESET_TIMEOUT, long *timeval) fd:file descriptor of mountpoint FIFREEZE_RESET_TIMEOUT: request code for reset of timeout period timeval: new timeout period in seconds Return value: 0 if the operation succeeds. Otherwise, -1 Error number: If the filesystem has already been unfrozen, errno is set to EINVAL. Any comments are very welcome. Cheers, Takashi