From mboxrd@z Thu Jan 1 00:00:00 1970 Received: by wa-out-1112.google.com with SMTP id m33so1065659wag.8 for ; Thu, 17 Jan 2008 05:16:47 -0800 (PST) Message-ID: <4df4ef0c0801170516k3f82dc69ieee836b5633378a@mail.gmail.com> Date: Thu, 17 Jan 2008 16:16:47 +0300 From: "Anton Salikhmetov" Subject: Re: [PATCH -v5 2/2] Updating ctime and mtime at syncing In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Content-Disposition: inline References: <12005314662518-git-send-email-salikhmetov@gmail.com> <1200531471556-git-send-email-salikhmetov@gmail.com> <4df4ef0c0801170416s5581ae28h90d91578baa77738@mail.gmail.com> Sender: owner-linux-mm@kvack.org Return-Path: To: Miklos Szeredi Cc: linux-mm@kvack.org, jakob@unthought.net, linux-kernel@vger.kernel.org, valdis.kletnieks@vt.edu, riel@redhat.com, ksm@42.dk, staubach@redhat.com, jesper.juhl@gmail.com, torvalds@linux-foundation.org, a.p.zijlstra@chello.nl, akpm@linux-foundation.org, protasnb@gmail.com, r.e.wolff@bitwizard.nl, hidave.darkstar@gmail.com, hch@infradead.org List-ID: 2008/1/17, Miklos Szeredi : > > > 4. Recording the time was the file data changed > > > > > > Finally, I noticed yet another issue with the previous version of my patch. > > > Specifically, the time stamps were set to the current time of the moment > > > when syncing but not the write reference was being done. This led to the > > > following adverse effect on my development system: > > > > > > 1) a text file A was updated by process B; > > > 2) process B exits without calling any of the *sync() functions; > > > 3) vi editor opens the file A; > > > 4) file data synced, file times updated; > > > 5) vi is confused by "thinking" that the file was changed after 3). > > Updating the time in remove_vma() would fix this, no? We need to save modification time. Otherwise, updating time stamps will be confusing the vi editor. > > > > All these changes to inode.c are unnecessary, I think. > > > > The first part is necessary to account for "remembering" the modification time. > > > > The second part is for handling block device files. I cannot see any other > > sane way to update file times for them. > > Use file_update_time(), which will do the right thing. It will in > fact do the same thing as write(2) on the device, which is really what > we want. > > Block devices being mapped for write through different device > nodes..., well, I don't think we really need to handle such weird > corner cases 100% acurately. The file_update_time() cannot be used for implementing the "auto-update" feature, because the sync() system call doesn't "know" about the file which was memory-mapped. > > Miklos > -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org