Date: Sat, 22 Sep 2012 18:20:26 +0200 From: Pawel Jakub Dawidek <pjd@FreeBSD.org> To: freebsd-geom@FreeBSD.org Subject: Re: geli and BIO_FLUSH and/or BIO_ORDERED issue? Message-ID: <20120922162025.GE1454@garage.freebsd.pl> In-Reply-To: <20120919040430.GF19036@funkthat.com> References: <20120919040430.GF19036@funkthat.com>
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--ryJZkp9/svQ58syV Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Tue, Sep 18, 2012 at 09:04:30PM -0700, John-Mark Gurney wrote: > I was looking at geli and I'm not sure if it's implementing BIO_FLUSH > and/or BIO_ORDERED properly... >=20 > >From my understanding is the BIO_ORDERED is suppose to wait for the > previous _WRITES to complete before returning so that you can ensure > that data is on disk, i.e. _ORDERED is set on a BIO_FLUSH... >=20 > BIO_ORDERED is handled by diskq_* code such that when you add an _ORDERED > command, all commands are put after it, but there doesn't appear to > be any code to ensure that an _ORDERED command waits for prevoius > pending commands to complete.. >=20 > This is extra obvious in eli in that a _FLUSH is immediately dispatched, > even when there may be _WRITEs that haven't been finished encrypting and > sent down to the disk to get _FLUSHed... >=20 > Any comments about this? Hmm, BIO_ORDERED was introduced pretty recently and GEOM classes were not updated to honour it, but it also seems to be to complex to handle in GEOM classes. I wonder if we could hold off new writes and wait for the in-progress writes in GEOM if we spot BIO_ORDERED request without the need to implement this logic in GEOM classes. --=20 Pawel Jakub Dawidek http://www.wheelsystems.com FreeBSD committer http://www.FreeBSD.org Am I Evil? Yes, I Am! http://tupytaj.pl --ryJZkp9/svQ58syV Content-Type: application/pgp-signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.19 (FreeBSD) iEYEARECAAYFAlBd5UkACgkQForvXbEpPzS/RQCgsP3zr1ssR/+lH/TUHFeHH9di eL8AnjUWMwvqrRkou4YKDe1snt5r/cVR =rs+F -----END PGP SIGNATURE----- --ryJZkp9/svQ58syV--
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