From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andy Lutomirski Subject: Re: [PATCH v3 2/5] fs: Add inode_update_time_writable Date: Mon, 19 Aug 2013 20:20:12 -0700 Message-ID: References: <20130820022822.GD6023@dastard> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: Jan Kara , Dave Hansen , "linux-kernel@vger.kernel.org" , xfs@oss.sgi.com, Christoph Hellwig , Theodore Ts'o , "linux-ext4@vger.kernel.org" , Tim Chen To: Dave Chinner Return-path: In-Reply-To: <20130820022822.GD6023@dastard> 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 Mon, Aug 19, 2013 at 7:28 PM, Dave Chinner wrote: > On Fri, Aug 16, 2013 at 04:22:09PM -0700, Andy Lutomirski wrote: >> This is like file_update_time, except that it acts on a struct inode * >> instead of a struct file *. >> >> Signed-off-by: Andy Lutomirski >> --- >> fs/inode.c | 72 ++++++++++++++++++++++++++++++++++++++++++------------ >> include/linux/fs.h | 1 + >> 2 files changed, 58 insertions(+), 15 deletions(-) >> [...] >> + >> +int inode_update_time_writable(struct inode *inode) >> +{ >> + struct timespec now; >> + int sync_it = prepare_update_cmtime(inode, &now); >> + int ret; >> + >> + if (!sync_it) >> + return 0; >> + >> + /* sb_start_pagefault and update_time can both sleep. */ >> + sb_start_pagefault(inode->i_sb); >> + ret = update_time(inode, &now, sync_it); >> + sb_end_pagefault(inode->i_sb); > > This gets called from the writeback path - you can't use > sb_start_pagefault/sb_end_pagefault in that path. The race I'm worried about is: - mmap - write to the mapping - remount ro - flush_cmtime -> inode_update_time_writable This may be impossible, in which case I'm okay, but it's nice to have a sanity check. I'll see if I can figure out how to do that. --Andy _______________________________________________ xfs mailing list xfs@oss.sgi.com http://oss.sgi.com/mailman/listinfo/xfs