Date: Sun, 03 Jul 2005 01:26:57 -0000 From: David Schultz <das@FreeBSD.ORG> To: Xin LI <delphij@delphij.net> Cc: cvs-src@FreeBSD.ORG, src-committers@FreeBSD.ORG, Xin LI <delphij@FreeBSD.ORG>, cvs-all@FreeBSD.ORG Subject: Re: cvs commit: src/sbin/fsck_ffs fsck.h pass5.c src/sys/ufs/ffs ffs_alloc.c ffs_softdep.c fs.h Message-ID: <20050221060844.GA700@VARK.MIT.EDU> In-Reply-To: <1108955636.624.16.camel@spirit> References: <200502200802.j1K82G2M003470@repoman.freebsd.org> <20050220231711.GA8172@VARK.MIT.EDU> <1108955636.624.16.camel@spirit>
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On Mon, Feb 21, 2005, Xin LI wrote: > 在 2005-02-20日的 18:17 -0500，David Schultz写道： > > > Since the summary is already re-sync'ed every 30 second, we will > > > not lag behind too much after a crash. With this consideration > > > in mind, it is more reasonable to transfer the responsibility to > > > background fsck, to reduce the delay after a crash. > > > > I'm not sure that I completely buy this explanation. If an > > application has a 1 GB temporary file open and unlinked at the > > time of the crash, then upon reboot, this change will make it seem > > as though I have 1 GB less space than I really do. This could > > lead to spurious disk full errors. (Or will that happen anyway if > > bgfsck hasn't recomputed all the free block bitmaps yet?) > > Hmm... Maybe we should add some constraint on this, for example, for > volumes that fssize < 20G do the recomputation at mount time, despite > the vfs.ffs.compute_summary_at_mount setting? I think the situation > only happens when bgfsck have not finished the scan yet, and on smaller > volumes, this should not affect so much (after all, we can always set > vfs.ffs.compute_summary_at_mount = 1 to restore the old behavior). > > Should I send a HEADSUP / update UPDATING so more people will know the > change? No, I don't think any major warnings or notices are needed. For about two years, IIRC, the SoftUpdates implementation would report spurious disk full errors when the disk was close to full, a large file was deleted, and another large file was immediately created, but practically nobody noticed at the time. I think practically nobody will notice your change either, except that they'll be glad that the time required to boot after a crash has dropped dramatically. ;-) A note in the fsck manpage couldn't hurt, though.
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