From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: with ECARTIS (v1.0.0; list xfs); Wed, 09 Jul 2008 06:55:13 -0700 (PDT) Received: from cuda.sgi.com (cuda2.sgi.com [192.48.168.29]) by oss.sgi.com (8.12.11.20060308/8.12.11/SuSE Linux 0.7) with ESMTP id m69Dt2xn014620 for ; Wed, 9 Jul 2008 06:55:04 -0700 Received: from casper.infradead.org (localhost [127.0.0.1]) by cuda.sgi.com (Spam Firewall) with ESMTP id 2CC802CE915 for ; Wed, 9 Jul 2008 06:56:05 -0700 (PDT) Received: from casper.infradead.org (casper.infradead.org [85.118.1.10]) by cuda.sgi.com with ESMTP id jQxmJ2otFpFsA7On for ; Wed, 09 Jul 2008 06:56:05 -0700 (PDT) Date: Wed, 9 Jul 2008 06:55:40 -0700 From: Arjan van de Ven Subject: Re: [PATCH 3/3] Add timeout feature Message-ID: <20080709065540.57305d91@infradead.org> In-Reply-To: <20080709114958.GV11558@disturbed> References: <20080709005254.GQ11558@disturbed> <20080709010922.GE9957@mit.edu> <20080709061621.GA5260@infradead.org> <20080708234120.5072111f@infradead.org> <20080708235502.1c52a586@infradead.org> <20080709071346.GS11558@disturbed> <20080709110900.GI9957@mit.edu> <20080709114958.GV11558@disturbed> Mime-Version: 1.0 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: Dave Chinner Cc: Theodore Tso , Miklos Szeredi , hch@infradead.org, pavel@suse.cz, t-sato@yk.jp.nec.com, akpm@linux-foundation.org, viro@ZenIV.linux.org.uk, linux-ext4@vger.kernel.org, xfs@oss.sgi.com, dm-devel@redhat.com, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, axboe@kernel.dk, mtk.manpages@googlemail.com On Wed, 9 Jul 2008 21:49:58 +1000 Dave Chinner wrote: > > (e) none of the above. The kernel compilation will appear to pause > until the filesystem is unfrozen. No other visible effect should > occur. It will get blocked in a write or filesystem transaction > because the fs is frozen. > > Look at vfs_check_frozen() - any call to that will block if the > filesystem is frozen or being frozen. The generic hook is in > __generic_file_aio_write_nolock() and various other filesystems have > calls in their specific write paths (fuse, ntfs, ocfs2, xfs, xip) to > do this. yeah and mmap doesn't happen > > For all other modifications, filesystem specific methods of > blocking transactions are used. XFS uses vfs_check_frozen() in > xfs_trans_alloc(), ext3 (and probably ocfs2) do it via > their ->write_super_lockfs method calling journal_lock_updates(), > ext4 via jbd2_lock_updates() and so on.... and what if it's the process that you need to unfreeze the fs later? Good luck. -- If you want to reach me at my work email, use arjan@linux.intel.com For development, discussion and tips for power savings, visit http://www.lesswatts.org