[XFS] Can't lock inodes in radix tree preload region

[XFS] Can't lock inodes in radix tree preload region

When we are inside a radix tree preload region, we cannot sleep. Recently
we moved the inode locking inside the preload region for the inode radix
tree. Fix that, and fix a missed unlock in another error path in the same
code at the same time.

SGI-PV: 987246

SGI-Modid: xfs-linux-melb:xfs-kern:32385a

Signed-off-by: David Chinner <[email protected]>
Signed-off-by: Lachlan McIlroy <[email protected]>
Signed-off-by: Christoph Hellwig <[email protected]>