Re: [Ext2-devel] Re: Kernel 2.6.6: Removing the last large file does not reset filesystem properties

From: Valdis . Kletnieks
Date: Tue May 11 2004 - 23:26:33 EST

On Tue, 11 May 2004 23:09:15 EDT, "Theodore Ts'o" said:

> Well, actially, the initscripts should reboot if the ((status & 2) != 0).
> Or more simply, if the exit status is 2 or 3.
> 4 - File system errors left uncorrected
> Which should cause the initscripts to call for help. An exit code of
> 2 or 3 merely means that the fsck is doing just fine, thank you very
> much, and just needs a reboot in order to flush the disk caches.

Man, a quarter of a century in this business, and I *still* haven't learned
that you can't trust your vendor to have a clue. That will teach me to go back
and check the upstream copy of the manpages, rather than trusting to memory and
a look at the rc.sysinit script. ;) It's been too long a week already...

It certainly looks like somebody needs to file a bug report against RedHat/
Fedora's initscripts, as it seems even more confused about the proper behavior
than I am ;) rc.sysinit interprets rc=0 as OK, rc=1 as "passed, keep on going"
(ignoring the remount issue, it just remounts r/w and goes on), and anything
greater than 1 as "yell for help". Oh, and to add to the pain - I just noticed
that it fsck's *all* the file systems, drops you into a shell if *any* of them
return a $? higher than 1, and when you exit that shell, it does:

umount -a
mount -n -o remount,ro /
reboot -f

(Yes, if a /userdata filesystem gets an rc2 and hasn't been mounted yet, we reboot anyhow.)

I've convinced myself that a crack pipe was involved in this code....

> P.S. The real right answer is that the fsck of the root partition
> should take place *before* the root partition is mounted, in the
> initial ramdisk. This gets rid of the whole need to flush the system
> caches, since the (real) root filesystem isn't mounted at all during
> the time of the initial check.

Right. Fortunately, RedHat appears to have put down the crack pipe long enough
to ship statically linked fsck.ext[23] and /sbin/lvm, so there's hope of having
enough of the pieces to do that....

Unfortunately, they then pick the pipe up again with mkinitrd - that uses the
'nash' shell wannabe, which does know how to invoke an external command, but
lacks an 'if' statement to test the return code (and yes, this time I checked
the actual nash.c from the src.rpm) - the various builtins and external commands
will set a return code, but you can't reference it except for the last
command's value could conceivably be checked back in init/do_mounts_initrd.c -
but that seems to discard the exit value of linuxrc....

Argh... :)

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