On a forced shutdown, xfs_finish_reclaim() will skip flushing the inode.
If the inode flush lock is not already held and there is an outstanding
xfs_iflush_done() then we might free the inode prematurely.  By acquiring
and releasing the flush lock we will synchronise with xfs_iflush_done().

Alternatively we could take a hold on the inode when when issuing I/Os
with xfs_iflush_done() and release it in xfs_iflush_done().  Would this
be a better approach?

Lachlan