[Ocfs2-devel] [PATCH 2/2] Ocfs2: Handle deletion of reflinked oprhan inodes correctly.

[Mark Fasheh]

On Fri, Mar 19, 2010 at 09:21:10AM +0800, Tristan Ye wrote:
> Current rule of orphan dir is that all inodes in the orphan dir
> have ORPHANED_FL, otherwise we treated it as an ERROR. this rule
> works well except for some rare cases of reflink operation:
> 
> http://oss.oracle.com/bugzilla/show_bug.cgi?id=1215
> 
> The problem is introduced by the essense of how reflink and our
> orphan_scan thread were working:
> 
>  * Orphan_scan scan the orphan dir into a queue first, and run
>    queue in a later time, we only hold the orphan_dir's lock
>    during scanning.
> 
>  * Reflink create a oprhaned target in orphan_dir at the first
>    step, and remove the targets and unset the flag at the third
>    step, these two steps respectively hold the orphan_dir's lock
>    themselves.
> 
> Based on above semantics, there is a possibility that a reflink
> inode can be moved out of the orphan dir and have its ORPHANED_FL
> cleared before the queue is run, which leads to a ERROR in
> ocfs2_query_wipde_inode().
> 
> This patch helps to judge if a orphan inode to be wiped off, which
> has NO ORPHANED_FL, is a legal alive reflinked target or not.
> 
> The patch also works for failed reflinked targets from a crash or
> other failures during the reflink operation, they can be wiped off
> as desired since these failed reflinked inodes always has ORPHANED_FL
> set ondisk.

How is this? Wouldn't the failed reflink still have OCFS2_HAS_REFCOUNT_FL
set as well as OCFS2_ORPHANED_FL? In the code below, we (correctly) skip
those for delete.


Btw, other than my question above, the patch looks correct for the case of
not wiping a reflinked inode.
	--Mark

--
Mark Fasheh