From mboxrd@z Thu Jan 1 00:00:00 1970 Subject: Re: [PATCH][RFC][BUG] updating the ctime and mtime time stamps in msync() In-Reply-To: Your message of "Wed, 09 Jan 2008 18:41:41 EST." <20080109184141.287189b8@bree.surriel.com> From: Valdis.Kletnieks@vt.edu References: <1199728459.26463.11.camel@codedot> <20080109155015.4d2d4c1d@cuia.boston.redhat.com> <26932.1199912777@turing-police.cc.vt.edu> <20080109170633.292644dc@cuia.boston.redhat.com> <20080109223340.GH25527@unthought.net> <20080109184141.287189b8@bree.surriel.com> Mime-Version: 1.0 Content-Type: multipart/signed; boundary="==_Exmh_1199998102_2824P"; micalg=pgp-sha1; protocol="application/pgp-signature" Content-Transfer-Encoding: 7bit Date: Thu, 10 Jan 2008 15:48:22 -0500 Message-ID: <5273.1199998102@turing-police.cc.vt.edu> Sender: owner-linux-mm@kvack.org Return-Path: To: Rik van Riel Cc: Jakob Oestergaard , Anton Salikhmetov , linux-mm@kvack.org, linux-kernel@vger.kernel.org List-ID: --==_Exmh_1199998102_2824P Content-Type: text/plain; charset=us-ascii On Wed, 09 Jan 2008 18:41:41 EST, Rik van Riel said: > I guess a third possible time (if we want to minimize the number of > updates) would be when natural syncing of the file data to disk, by > other things in the VM, would be about to clear the I_DIRTY_PAGES > flag on the inode. That way we do not need to remember any special > "we already flushed all dirty data, but we have not updated the mtime > and ctime yet" state. > > Does this sound reasonable? Is it possible that a *very* large file (multi-gigabyte or even bigger database, for example) would never get out of I_DIRTY_PAGES, because there's always a few dozen just-recently dirtied pages that haven't made it out to disk yet? Of course, getting a *consistent* backup of a file like that is quite the challenge already, because of the high likelyhood of the file being changed while the backup runs - that's why big sites often do a 'quiesce/snapshot/wakeup' on a database and then backup the snapshot... --==_Exmh_1199998102_2824P Content-Type: application/pgp-signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.8 (GNU/Linux) Comment: Exmh version 2.5 07/13/2001 iD8DBQFHhoSWcC3lWbTT17ARAn1mAJ48AjVv7lCnK64HDWknbOZPhx4kZgCeNAAx 1fx+ay5cVP3Trm0CcZPIZO8= =DyL9 -----END PGP SIGNATURE----- --==_Exmh_1199998102_2824P-- -- 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