From ab1fbc60d1f924d4ccbe645ce6e7e5df10d923e2 Mon Sep 17 00:00:00 2001
From: Theodore Ts'o <tytso@mit.edu>
Date: Mon, 28 Sep 2009 15:58:29 -0400
Subject: [PATCH 45/85] ext4: EXT4_IOC_MOVE_EXT: Check for different original and donor inodes first

(cherry picked from commit f3ce8064b388ccf420012c5a4907aae4f13fe9d0)

Move the check to make sure the original and donor inodes are
different earlier, to avoid a potential deadlock by trying to lock the
same inode twice.

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
---
 fs/ext4/move_extent.c |   16 ++++++++--------
 1 file changed, 8 insertions(+), 8 deletions(-)

--- a/fs/ext4/move_extent.c
+++ b/fs/ext4/move_extent.c
@@ -1001,14 +1001,6 @@ mext_check_arguments(struct inode *orig_
 		return -EINVAL;
 	}
 
-	/* orig and donor should be different file */
-	if (orig_inode->i_ino == donor_inode->i_ino) {
-		ext4_debug("ext4 move extent: The argument files should not "
-			"be same file [ino:orig %lu, donor %lu]\n",
-			orig_inode->i_ino, donor_inode->i_ino);
-		return -EINVAL;
-	}
-
 	/* Ext4 move extent supports only extent based file */
 	if (!(EXT4_I(orig_inode)->i_flags & EXT4_EXTENTS_FL)) {
 		ext4_debug("ext4 move extent: orig file is not extents "
@@ -1232,6 +1224,14 @@ ext4_move_extents(struct file *o_filp, s
 	int block_len_in_page;
 	int uninit;
 
+	/* orig and donor should be different file */
+	if (orig_inode->i_ino == donor_inode->i_ino) {
+		ext4_debug("ext4 move extent: The argument files should not "
+			"be same file [ino:orig %lu, donor %lu]\n",
+			orig_inode->i_ino, donor_inode->i_ino);
+		return -EINVAL;
+	}
+
 	/* protect orig and donor against a truncate */
 	ret1 = mext_inode_double_lock(orig_inode, donor_inode);
 	if (ret1 < 0)