Re: [PATCH 6/6] XFS: Prevent looping in xfs_sync_inodes_ag

[Christoph Hellwig <hch@infradead.org>]

On Wed, Oct 08, 2008 at 08:54:40AM +1100, Dave Chinner wrote:
> If the last  block of the AG has inodes in it and the AG is an
> exactly power-of-2 size then the last inode in the AG points
> to the last block in the AG. If we try to find the next inode
> in the AG by adding one to the inode number, we increment the
> inode number past the size of the AG. The result is that the
> macro XFS_INO_TO_AGINO() will strip the AG portion of the inode
> number and return an inode number of zero.
> 
> That is, instead of terminating the lookup loop because we hit the
> inode number went outside the valid range for the AG, the search
> index returns to zero and we start traversing the radix tree from
> the start again. This results in an endless loop in
> xfs_sync_inodes_ag().
> 
> Fix it be detecting if the new search index decreases as a result of
> incrementing the current inode number. That indicate an overflow and
> hence that we have finished processing the AG so we can terminate
> the loop.

Shouldn't this get merged into the patch that introduces the radix-tree
based sync?