Date: Sun, 22 Apr 2007 18:45:28 +0200 From: Pawel Jakub Dawidek <pjd@FreeBSD.org> To: Ivan Voras <ivoras@fer.hr> Cc: freebsd-geom@FreeBSD.org Subject: Re: gjournal & async Message-ID: <20070422164528.GE52622@garage.freebsd.pl> In-Reply-To: <462B8D25.3000303@fer.hr> References: <f0eb3i$97s$2@sea.gmane.org> <20070422123852.GA52622@garage.freebsd.pl> <462B83D7.1010905@fer.hr> <20070422162601.GD52622@garage.freebsd.pl> <462B8D25.3000303@fer.hr>
next in thread | previous in thread | raw e-mail | index | archive | help
--//IivP0gvsAy3Can Content-Type: text/plain; charset=iso-8859-2 Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Sun, Apr 22, 2007 at 06:28:21PM +0200, Ivan Voras wrote: > Pawel Jakub Dawidek wrote: > > On Sun, Apr 22, 2007 at 05:48:39PM +0200, Ivan Voras wrote: > >> Pawel Jakub Dawidek wrote: > >>> On Sun, Apr 22, 2007 at 02:43:29AM +0200, Ivan Voras wrote: > >>>> How does gjournal guarantee corectness if UFS is mounted async? AFAIK > >>>> the "async" handling of IO requests is done by the UFS, the writes a= re > >>>> not rescheduled at the GEOM layer? > >>> GJournal has some minimum knowledge about VFS. Before it does journal > >>> switch, it synchronize and suspends file system. This way we can be s= ure > >>> everything is on disk in a consistent state. > >> Thanks. So, this (async support) could actually work with other file > >> systems, like ext2 and msdos? > >=20 > > Once gjournal is taught about them, yes. >=20 > Then you're not interfacing in the VFS layer, you're hooking directly > into UFS? GJournal talks to VFS to sync/suspend file system, but it also needs to have some knowledge about file system to mark it as clean, so fsck won't complain. Look at sys/geom/journal/g_journal_ufs.c (dirty method is mostly not used, it is there for consistency and in case journal itself become broken/corrupted). --=20 Pawel Jakub Dawidek http://www.wheel.pl pjd@FreeBSD.org http://www.FreeBSD.org FreeBSD committer Am I Evil? Yes, I Am! --//IivP0gvsAy3Can Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.6 (FreeBSD) iD8DBQFGK5EoForvXbEpPzQRAtBpAKCFTSL8Dh7Uj8jgCuivm9R1hnms1gCgl4Tz dXlHRMaaAMxf9dR81VaA9ZQ= =8wfy -----END PGP SIGNATURE----- --//IivP0gvsAy3Can--
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?20070422164528.GE52622>