[Linux-cluster] Found unlinked inode

[Borgström Jonas]

From: linux-cluster-bounces at redhat.com [mailto:linux-cluster-bounces at redhat.com] On Behalf Of Wendy Cheng
Sent: den 26 september 2007 19:37
To: linux clustering
Subject: Re: [Linux-cluster] Found unlinked inode
> 
> Wendy Cheng wrote:
>
> >
> > Just read this mail - not sure the running kernel version where this 
> > problem occurs . However, GFS1's unlinked inodes are linked into a 
> > list that are cleaned up by gfs_inoded (a daemon). So there is a time 
> > gap between the file is deleted and its on-disk inode is actually 
> > removed. There are two possibilities for this problem to occur:
> >
> > 1. An unclean shutdown where this linked list is not completely walked 
> > thru and cleaned up.
> > 2. Possible bugs in RHEL5 based kernels (where gfs umount logic may 
> > accidentally overlook this clean-up logic).
> >
> > In any case, I don't view this as a filesystem corruption - but the 
> > unlinked inodes would take some extra disk space that can only be 
> > cleaned up by fsck (and/or journal replay if the journal stil has the 
> > file remove transaction).
> >
>
> Got some private emails in my folder... look like I didn't explain 
> things well... An unlinked inode is an inode that has been removed from 
> directory (so you would not be able to access it from operating system's 
> lookup routine). If you (as an application) need to access a file with 
> the same name, you would have to (re)create it (then gfs1 will assign a 
> new inode for that new file).
>
> For this issue, the unlinked inode doesn't affect the correctness of the 
> filesystem operations. You can still safely use the filesystem, except 
> these orphan inodes will take extra disk space.

Hi Wendy, thanks for your answer.

To answer your earlier question, the kernel version used is 2.6.18-8.1.8.el5. I just noticed that a never kernel version is available, but as far as I can tell this is a security release and the changelog doesn't mention any changes to the GFS filesystem...

So if I understood you correctly this is a known bug/limitation that might orphan already deleted inodes if a node crashes before gfs_inoded had a chance to free them. And the only downside is some lost disk space which can be reclaimed by running gfs_fsck. This is good news.

Regards,
Jonas
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