Date: Thu, 28 Feb 2013 18:01:46 +0100 From: Ivan Voras <ivoras@freebsd.org> To: freebsd-geom@freebsd.org Cc: freebsd-fs@freebsd.org Subject: Re: Unexpected SU+J inconsistency AGAIN -- please, don't shift topic to ZFS! Message-ID: <kgo2hn$f1s$1@ger.gmane.org> In-Reply-To: <1502041051.20130228185647@serebryakov.spb.ru> References: <1796551389.20130228120630@serebryakov.spb.ru> <1238720635.20130228123325@serebryakov.spb.ru> <1158712592.20130228141323@serebryakov.spb.ru> <CAPJF9w=CZg_%2BK7NHTGUhRLaMJWWNOG7zMipGMJL6w6NoNZpSXA@mail.gmail.com> <583012022.20130228143129@serebryakov.spb.ru> <kgnp1n$9mc$1@ger.gmane.org> <1502041051.20130228185647@serebryakov.spb.ru>
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This is an OpenPGP/MIME signed message (RFC 2440 and 3156) --------------enig12065FB88A964A3B91C9C4FD Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable On 28/02/2013 15:56, Lev Serebryakov wrote: > One time, Kirk say, that delayed writes are Ok for SU until bottom > layer doesn't lie about operation completeness. geom_raid5 could > delay writes (in hope that next writes will combine nicely and allow > not to do read-calculate-write cycle for read alone), but it never > mark BIO complete until it is really completed (layers down to > geom_raid5 returns completion). So, every BIO in wait queue is "in > flight" from GEOM/VFS point of view. Maybe, it is fatal for journal :(= It shouldn't be - it could be a bug. > And want I really want to see is "SYNC" flag for BIO and that all > journal-related writes will be marked with it. Also all commits > originated with fsync() MUST be marked in same way, really. Alexander > Motin (ahci driver author) assured me, that he'll add support for > such flag in driver to flush drive cache too, if it will be > introduced. Hmmm, once upon a time I actually tried to add it: http://people.freebsd.org/~ivoras/diffs/fsync_flush.patch This is from 2011, and was never really reviewed. Kirk said it was a good idea (meaning the implementation could be wrong, YMMV) :) I don't know whether it's significant, but ffs_softdep.c contains 6 bawrite() calls (meaning buf async write), in softdep_process_journal(), softdep_journal_freeblocks(), softdep_fsync_mountdev(), sync_cgs(), and flush_deplist(). --------------enig12065FB88A964A3B91C9C4FD Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.19 (FreeBSD) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org/ iEYEARECAAYFAlEvjXoACgkQ/QjVBj3/HSzgXQCZASkd1JTlv/mRSlZ8EdNtqVwp XNUAoI6V2WCe4D9mfizE/RTDA1g0SKrL =eK7Y -----END PGP SIGNATURE----- --------------enig12065FB88A964A3B91C9C4FD--
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