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/file.c b/fs/jfs/file.c
index 0e026a7..4ce7735 100644
--- a/fs/jfs/file.c
+++ b/fs/jfs/file.c
@@ -38,17 +38,17 @@
 	if (rc)
 		return rc;
 
-	mutex_lock(&inode->i_mutex);
+	inode_lock(inode);
 	if (!(inode->i_state & I_DIRTY_ALL) ||
 	    (datasync && !(inode->i_state & I_DIRTY_DATASYNC))) {
 		/* Make sure committed changes hit the disk */
 		jfs_flush_journal(JFS_SBI(inode->i_sb)->log, 1);
-		mutex_unlock(&inode->i_mutex);
+		inode_unlock(inode);
 		return rc;
 	}
 
 	rc |= jfs_commit_inode(inode, 1);
-	mutex_unlock(&inode->i_mutex);
+	inode_unlock(inode);
 
 	return rc ? -EIO : 0;
 }