Date: Mon, 4 Jul 2005 11:54:31 +0200 From: Dario Freni <saturnero@freesbie.org> To: Stephan Uphoff <ups@tree.com> Cc: freebsd-fs@freebsd.org Subject: Re: [saturnero@freesbie.org: Weird behaviour of mount_unionfs with executables] Message-ID: <20050704095431.GA31030@cvs.freesbie.org> In-Reply-To: <1120437780.77984.38252.camel@palm> References: <20050703181616.GC89744@cvs.freesbie.org> <42C83643.4010506@samsco.org> <20050703201621.GD89744@cvs.freesbie.org> <1120425831.77984.37993.camel@palm> <42C87CAE.7080802@samsco.org> <1120436351.77984.38195.camel@palm> <42C88121.8010602@samsco.org> <1120437780.77984.38252.camel@palm>
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--sm4nu43k4a2Rpi4c Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Sun, Jul 03, 2005 at 08:43:01PM -0400, Stephan Uphoff wrote: > On Sun, 2005-07-03 at 20:21, Scott Long wrote: > > Stephan Uphoff wrote: > > > On Sun, 2005-07-03 at 20:02, Scott Long wrote: > > >=20 > > >>Stephan Uphoff wrote: > > >> > > >>>I suspect the changes in revision 1.272 of kern_exec.c trigger the > > >>>copy operation. > > >>> > > >>>Looks like you need a noatime option for union_fs. > > >>> > > >>>Stephan > > >> > > >>Does this mean that every vnode that gets executed gets dirtied and a= ll > > >>its pages resynced to the backing store, or just the inode block? > > >=20 > > >=20 > > > The kernel calls VOP_SETATTR to set the access time of the file. > > > union_fs detects that it does not have an upper layer copy of the file > > > to modify the attributes on and decides to copy it. > > > The vm layer does not (directly) come into play on this.=20 > > >=20 > > > Stephan > > >=20 > >=20 > > Ok, so this is just a limitation of unionfs, not the vnode pager. You > > had me scared that we'd be doing a whole lot of needless disk i/o. >=20 > YES - and it looks like just specifying noatime for the union mount > should fix the copy problem for FreeSBIE. Correct. Using -o noatime when mounting the unionfs resolves all above problems. Thank you very much. --=20 Dario Freni (saturnero@freesbie.org) FreeSBIE developer (http://www.freesbie.org) GPG Public key at http://www.saturnero.net/saturnero.asc --sm4nu43k4a2Rpi4c Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.0 (FreeBSD) iD8DBQFCyQdVymi72IiShysRAsgCAJ98v2WiT1jj4DG/xo5cHWCj95qqIQCfev5Z XOBQpB6B9VHpFSpIJkTZFAk= =vwJ2 -----END PGP SIGNATURE----- --sm4nu43k4a2Rpi4c--
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