[Ocfs2-devel] Ocfs2 leaking inodes on failed allocation

[Joel Becker]

On Tue, Apr 20, 2010 at 08:00:54PM +0200, Jan Kara wrote:
> the following errors:
> 1163.522931] (4774,1):ocfs2_query_inode_wipe:898 ERROR: bug expression:
> !(di->i_flags & cpu_to_le32(OCFS2_ORPHANED_FL))
> [ 1163.522938] (4774,1):ocfs2_query_inode_wipe:898 ERROR: Inode 77233
> (on-disk 77233) not orphaned! Disk flags  0x1, inode flags 0x0

	See the thread starting "Subject: [Ocfs2-devel] [PATCH] ocfs2:
alloc orphaned inode in ocfs2_symlink".  I'll sum up here.

> The easiest solution would be to always create inodes in the orphan
> directory (we even have a function ocfs2_create_inode_in_orphan for this).
> The downside this has would be that I expect we would start contending on
> orphan dir i_mutex quite early and thus fs scalability would suffer a lot.
> Also there's some additional IO and CPU cost involved...

	Yeah, this is a non-starter.

> The last idea I have is that we could "undo" the inode allocation and
> other operations we did in the transaction so far. But looking at the code
> it would get nasty quickly - all the xattr handling which gets inode locks,
> starts & stops transactions, etc...

	This is the "best" solution, but it requires some thought and
care.  We'd love to get here someday.

> Any other ideas? What would make things much easier would be if orphan
> handling was more lightweight like it is e.g. in ext3 / ext4 - there we
> have just linked list of orphaned inodes and so if we decide an inode needs
> to be orphaned, we just have to modify the superblock (orphan list head)
> and the inode (to point at the current orphan list head)... In OCFS2 we
> could have a per-slot lists like this but a change like this would probably
> be an overkill for the above bug so it would make sence only if there would
> be other benefits from this.

	We're not going to change our orphan storage, either.  This
still needs locking in the cluster, and that's just a pain.
	Near the end of the referenced thread, Mark told Dong Yang to
implement the OCFS2_INODE_SKIP_ORPHAN_DIR flag.  This flag merely lets
delete_inode know that we never orphaned the sucker.  delete_inode can
do the rest of its work without triggering the above warning.

Joel

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Joel Becker
Principal Software Developer
Oracle
E-mail: joel.becker at oracle.com
Phone: (650) 506-8127