Re: Htree ate my hard drive, was: post-halloween 0.2

Petr Vandrovec (VANDROVE@vc.cvut.cz)
Thu, 31 Oct 2002 13:19:23 +0200


On 31 Oct 02 at 9:20, Duncan Sands wrote:
> > I wonder if there is still a bug in the e2fsck code for re-hashing
> > directories? It shouldn't be possible to have e2fsck complete and
> > there still be an error in the filesystem (ok, sometimes it happens,
> > but in those cases it spews a lot of warnings about the filesystem
> > not being fixed yet and to run manually).
>
> It is possible that the filesystem was fine when fsck completed, but
> was damaged afterwards, i.e. in the time between fsck completing
> and the reboot.

Just stupid idea. Two or three months ago I complained that if
my box crashes shortly after boot, following things happen:

(1) system for some reason reads /var/run directory to page cache
(2) fsck finds that /var/run/* entries points to invalid nodes, and
removes them (through block device access)
(4) / is remounted read-write
(5) because of page cache for block device and directory is not
coherent (or what...), system still sees /var/run/* populated
(6) rm /var/run/* is run. FS is remounted read-only due to
freeing inode already freeed...
(7) Reboot, run fsck again, reboot, fine...

Nobody answered it at that time, and it happened at least 5 times
again to me - until I modified initscripts to do unconditional
reboot if "fsck /" did ANY modifications to filesystem.

Maybe kernel still uses old directory indexes structure after
fsck created new one?
Best regards,
Petr Vandrovec
vandrove@vc.cvut.cz

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