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/super.c b/fs/jfs/super.c
index 900925b..4f5d85b 100644
--- a/fs/jfs/super.c
+++ b/fs/jfs/super.c
@@ -792,7 +792,7 @@
 	struct buffer_head tmp_bh;
 	struct buffer_head *bh;
 
-	mutex_lock(&inode->i_mutex);
+	inode_lock(inode);
 	while (towrite > 0) {
 		tocopy = sb->s_blocksize - offset < towrite ?
 				sb->s_blocksize - offset : towrite;
@@ -824,7 +824,7 @@
 	}
 out:
 	if (len == towrite) {
-		mutex_unlock(&inode->i_mutex);
+		inode_unlock(inode);
 		return err;
 	}
 	if (inode->i_size < off+len-towrite)
@@ -832,7 +832,7 @@
 	inode->i_version++;
 	inode->i_mtime = inode->i_ctime = CURRENT_TIME;
 	mark_inode_dirty(inode);
-	mutex_unlock(&inode->i_mutex);
+	inode_unlock(inode);
 	return len - towrite;
 }