[PATCH] xfs: fix node forward in xfs_node_toosmall

[Greg KH]

On Tue, Oct 08, 2013 at 07:09:26PM -0500, Ben Myers wrote:
> From: Mark Tinguely <tinguely at sgi.com>
> 
> Commit f5ea1100 cleans up the disk to host conversions for
> node directory entries, but because a variable is reused in
> xfs_node_toosmall() the next node is not correctly found.
> If the original node is small enough (<= 3/8 of the node size),
> this change may incorrectly cause a node collapse when it should
> not. That will cause an assert in xfstest generic/319:
> 
>    Assertion failed: first <= last && last < BBTOB(bp->b_length),
>    file: /root/newest/xfs/fs/xfs/xfs_trans_buf.c, line: 569
> 
> Keep the original node header to get the correct forward node.
> 
> (When a node is considered for a merge with a sibling, it overwrites the
>  sibling pointers of the original incore nodehdr with the sibling's
>  pointers.  This leads to loop considering the original node as a merge
>  candidate with itself in the second pass, and so it incorrectly
>  determines a merge should occur.)
> 
> upstream commit 997def25e4b9cee3b01609e18a52f926bca8bd2b

Applied to the 3.10 and 3.11 stable queues, thanks.

greg k-h