[PATCH v2 4/4] fs/dcache: Protect negative dentry pruning from racing with umount

The negative dentry pruning is done on a specific super_block set in the ndblk.prune_sb variable. If the super_block is also being un-mounted concurrently, the content of the super_block may no longer be valid. To protect against such racing condition, a new lock is added to the ndblk structure

[PATCH v2 4/4] fs/dcache: Protect negative dentry pruning from racing with umount

The negative dentry pruning is done on a specific super_block set in the ndblk.prune_sb variable. If the super_block is also being un-mounted concurrently, the content of the super_block may no longer be valid. To protect against such racing condition, a new lock is added to the ndblk structure