From mboxrd@z Thu Jan 1 00:00:00 1970 From: Theodore Ts'o Subject: Re: [PATCH 3/4] fs: Remove i_size check from do_fallocate Date: Sat, 12 Apr 2014 09:59:06 -0400 Message-ID: <20140412135906.GC13837@thunk.org> References: <1397242665-2183-1-git-send-email-lczerner@redhat.com> <1397242665-2183-3-git-send-email-lczerner@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: linux-fsdevel@vger.kernel.org, ceph-devel@vger.kernel.org, linux-ext4@vger.kernel.org, xfs@oss.sgi.com To: Lukas Czerner Return-path: Content-Disposition: inline In-Reply-To: <1397242665-2183-3-git-send-email-lczerner@redhat.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: xfs-bounces@oss.sgi.com Sender: xfs-bounces@oss.sgi.com List-Id: linux-ext4.vger.kernel.org On Fri, Apr 11, 2014 at 08:57:44PM +0200, Lukas Czerner wrote: > Currently in do_fallocate in collapse range case we're checking whether > offset + len is not bigger than i_size. However there is nothing which > would prevent i_size from changing so the check is pointless. It should > be done in the file system itself and the file system needs to make sure > that i_size is not going to change. > > As it is now we can easily crash kernel by having two processes doing > truncate and fallocate collapse range at the same time. This can be > reproduced on ext4 and it is theoretically possible on xfs even though I > was not able to trigger it with this simple test. > > This commit removes the check from do_fallocate and adds it to the file > system. > > Signed-off-by: Lukas Czerner > --- > fs/ext4/extents.c | 11 +++++++++-- > fs/open.c | 8 -------- > fs/xfs/xfs_file.c | 10 +++++++++- > 3 files changed, 18 insertions(+), 11 deletions(-) Looks good to me. Do the xfs folks mind if I carry this in the ext4 tree and push it to Linus shortly after -rc1? If so, please send me an ack'ed by. If folks have a strong preference to handle this differently, let me know. Cheers, - Ted _______________________________________________ xfs mailing list xfs@oss.sgi.com http://oss.sgi.com/mailman/listinfo/xfs