[45/90] ext4: EXT4_IOC_MOVE_EXT: Check for different original and donor inodes first

Greg KH
2009-12-11T04:51:51Z

[-- Attachment #1: 0045-ext4-EXT4_IOC_MOVE_EXT-Check-for-different-original-.patch --]
[-- Type: text/plain, Size: 1629 bytes --]

2.6.31-stable review patch. If anyone has any objections, please let us know.

------------------
(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)