wrappers for ->i_mutex access

parallel to mutex_{lock,unlock,trylock,is_locked,lock_nested},
inode_foo(inode) being mutex_foo(&inode->i_mutex).

Please, use those for access to ->i_mutex; over the coming cycle
->i_mutex will become rwsem, with ->lookup() done with it held
only shared.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/fs/jfs/ioctl.c b/fs/jfs/ioctl.c
index 8db8b7d..8653cac 100644
--- a/fs/jfs/ioctl.c
+++ b/fs/jfs/ioctl.c
@@ -96,7 +96,7 @@
 		}
 
 		/* Lock against other parallel changes of flags */
-		mutex_lock(&inode->i_mutex);
+		inode_lock(inode);
 
 		jfs_get_inode_flags(jfs_inode);
 		oldflags = jfs_inode->mode2;
@@ -109,7 +109,7 @@
 			((flags ^ oldflags) &
 			(JFS_APPEND_FL | JFS_IMMUTABLE_FL))) {
 			if (!capable(CAP_LINUX_IMMUTABLE)) {
-				mutex_unlock(&inode->i_mutex);
+				inode_unlock(inode);
 				err = -EPERM;
 				goto setflags_out;
 			}
@@ -120,7 +120,7 @@
 		jfs_inode->mode2 = flags;
 
 		jfs_set_inode_flags(inode);
-		mutex_unlock(&inode->i_mutex);
+		inode_unlock(inode);
 		inode->i_ctime = CURRENT_TIME_SEC;
 		mark_inode_dirty(inode);
 setflags_out: