Re: ext4_clear_journal_err: Filesystem error recorded from previous mount: IO failure

[Bernd Schubert <bschubert@ddn.com>]

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On 10/24/2010 03:08 AM, Ted Ts'o wrote:
> On Sun, Oct 24, 2010 at 02:20:45AM +0200, Bernd Schubert wrote:
>> Hmm, maybe we have a mis-understanding here. If we could make e2fsck
>> to *only* recovery the journal, that would be perfect. Kernel and
>> e2fsck journal recovery should take approximately the same time. But
>> that option does not exist yet (well, a half baken patch is on my
>> disk now). If e2fsck then would detect as the kernel:
>> "clear_journal_err: Filesystem error recorded from previous mount"
>> and mark the filesystem with an error, that would be all we need to
>> then abort the mount in the pacemaker script and allow us to run a
>> real e2fsck outside of pacemaker.
> 
> What probably makes sense is to have an extended option which causes
> e2fsck to just run the journal and then exit.  Part of running the
> journal should be setting the EXT4_ERROR_FS bit in s_mount_state and
> then clearning the journal.  That seems to be missing entirely from
> e2fsck, which is a bug that we should fix regardless.

Adding the journal option is simple, I will provide a patch by Wednesday
or Thursday. Will also check if it sets EXT2_ERROR_FS and if not, will
try to find some time to add that.

> 
> As far as detecting whether or not the file system has known errors,
> you can do that by using dumpe2fs -h and grepping for "Filesystem
> state".  That can have the values "clean" or "with errors".  (For ext2
> file systems, or ext4 file systems without a journal, you can also
> have the state "not clean" and "not clean with errors", but if you
> have a journal the latter two states shouldn't ever come up.)

I added exactly that to our lustre_server pacemaker agent last week :)
And when I noticed it still mounts filesystems with errors, I started
this thread here.


> 
> That way the logic that you want is something you can build into your
> script, and we don't need to embed application specific logic into
> e2fsprogs.  The ability to just run the journal without doing any
> further checking seems like a reasonable thing to add to e2fsck ---
> and by using dumpe2fs -h you'll be able to detect all possible file
> system errors (not just the ones which are reported via the journal
> error system).
> 
> Does that sound reasonable to you?

Yes, we perfectly agree on each other now :)

Thanks,
Bernd


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