[PATCH 10/11] xfs: clean up root inode properly on mount failure

[Christoph Hellwig]

On Thu, Aug 06, 2015 at 01:44:31PM -0400, Brian Foster wrote:
> The root inode is read as part of the xfs_mountfs() sequence and the
> reference is dropped in the event of failure after we grab the inode.
> The reference drop doesn't necessarily free the inode, however. It marks
> it for reclaim and potentially kicks off the reclaim workqueue.  The
> workqueue is destroyed further up the error path, which means we are
> subject to crash if the workqueue job runs after this point or a memory
> leak which is identified if the xfs_inode_zone is destroyed (e.g., on
> module removal). Both of these outcomes are reproducible via manual
> instrumentation of a mount error after the root inode xfs_iget() call in
> xfs_mountfs().
> 
> Update the xfs_mountfs() error path to cancel any potential reclaim work
> items and to run a synchronous inode reclaim if the root inode is marked
> for reclaim. This ensures that no jobs remain on the queue before it is
> destroyed and that the root inode is freed before the reclaim mechanism
> is torn down.
> 
> Signed-off-by: Brian Foster <bfoster at redhat.com>

Looks good,

Reviewed-by: Christoph Hellwig <hch at lst.de>