[PATCH] Rearrangement of inode_lock in writeback_inodes()

This patch reaaranges inode_lock taking in writeback_inodes().  It narrows
down use of inode_lock and removes unneccassary nesting of sb_lock and
inode_lock.  Instead of holding inode_lock for all the time I moved it
around sync_sb_inodes() as it is in all other places.
Signed-Off-By: Kirill Korotaev <dev@sw.ru>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

fs/fs-writeback.c

@@ -403,7 +403,6 @@ writeback_inodes(struct writeback_control *wbc)
 	struct super_block *sb;
 
 	might_sleep();
-	spin_lock(&inode_lock);
 	spin_lock(&sb_lock);
 restart:
 	sb = sb_entry(super_blocks.prev);
@@ -418,8 +417,11 @@ writeback_inodes(struct writeback_control *wbc)
 			 * be unmounted by the time it is released.
 			 */
 			if (down_read_trylock(&sb->s_umount)) {
-				if (sb->s_root)
+				if (sb->s_root) {
+					spin_lock(&inode_lock);
 					sync_sb_inodes(sb, wbc);
+					spin_unlock(&inode_lock);
+				}
 				up_read(&sb->s_umount);
 			}
 			spin_lock(&sb_lock);
@@ -430,7 +432,6 @@ writeback_inodes(struct writeback_control *wbc)
 			break;
 	}
 	spin_unlock(&sb_lock);
-	spin_unlock(&inode_lock);
 }
 
 /*