inode: move to per-sb LRU locks

With the inode LRUs moving to per-sb structures, there is no longer
a need for a global inode_lru_lock. The locking can be made more
fine-grained by moving to a per-sb LRU lock, isolating the LRU
operations of different filesytsems completely from each other.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 9724f0a..460d2cc 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -1397,7 +1397,8 @@
 	struct list_head	s_dentry_lru;	/* unused dentry lru */
 	int			s_nr_dentry_unused;	/* # of dentry on lru */
 
-	/* inode_lru_lock protects s_inode_lru and s_nr_inodes_unused */
+	/* s_inode_lru_lock protects s_inode_lru and s_nr_inodes_unused */
+	spinlock_t		s_inode_lru_lock ____cacheline_aligned_in_smp;
 	struct list_head	s_inode_lru;		/* unused inode lru */
 	int			s_nr_inodes_unused;	/* # of inodes on lru */