From mboxrd@z Thu Jan 1 00:00:00 1970 Subject: Re: [PATCH 2/2][RFC][BUG] msync: updating ctime and mtime at syncing From: Peter Zijlstra In-Reply-To: <4df4ef0c0801120438n4a3c1cfpd3563531929a1a91@mail.gmail.com> References: <1200006638.19293.42.camel@codedot> <1200012249.20379.2.camel@codedot> <1200130565.7999.8.camel@lappy> <1200130844.7999.12.camel@lappy> <4df4ef0c0801120438n4a3c1cfpd3563531929a1a91@mail.gmail.com> Content-Type: text/plain Date: Sat, 12 Jan 2008 14:09:01 +0100 Message-Id: <1200143342.7999.25.camel@lappy> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: Anton Salikhmetov 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 List-ID: On Sat, 2008-01-12 at 15:38 +0300, Anton Salikhmetov wrote: > 2008/1/12, Peter Zijlstra : > > > > On Sat, 2008-01-12 at 10:36 +0100, Peter Zijlstra wrote: > > > On Fri, 2008-01-11 at 03:44 +0300, Anton Salikhmetov wrote: > > > > > > > +/* > > > > + * Update the ctime and mtime stamps after checking if they are to be updated. > > > > + */ > > > > +void mapped_file_update_time(struct file *file) > > > > +{ > > > > + if (test_and_clear_bit(AS_MCTIME, &file->f_mapping->flags)) { > > > > + get_file(file); > > > > + file_update_time(file); > > > > + fput(file); > > > > + } > > > > +} > > > > + > > > > > > I don't think you need the get/put file stuff here, because > > > > BTW, the reason for me noticing this is that if it would be needed there > > is a race condition right there, who is to say that the file pointer > > you're deref'ing in your test condition isn't a dead one already. > > So, in your opinion, is it at all needed here to play with the file reference > counter? May I drop the get_file() and fput() calls from the > sys_msync() function? No, the ones in sys_msync() around calling do_fsync() are most definately needed because we release mmap_sem there. What I'm saying is that you can remove the get_file()/fput() calls from your new mapped_file_update_time() function. -- 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