ext4: fix smatch warning in move_extent.c's mext_replace_branches()

Commit 2147b1a6a4 resulted in a new smatch warning:

> fs/ext4/move_extent.c:693 mext_replace_branches()
> 	 warn: variable dereferenced before check 'dext' (see line 683)

Fix this by adding a check to make sure dext is non-NULL before we
derefrence it.

Signed-off-by: Akria Fujita <a-fujita@rs.jp.nec.com>
[ modified by tytso to make sure an ext4_error is called ]
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
This commit is contained in:
Akria Fujita 2013-02-01 20:52:46 -05:00 committed by Theodore Ts'o
parent 524c19ebc9
commit 87e698734b
1 changed files with 4 additions and 1 deletions

View File

@ -681,6 +681,8 @@ mext_replace_branches(handle_t *handle, struct inode *orig_inode,
depth = ext_depth(donor_inode);
dext = donor_path[depth].p_ext;
if (unlikely(!dext))
goto missing_donor_extent;
tmp_dext = *dext;
*err = mext_calc_swap_extents(&tmp_dext, &tmp_oext, orig_off,
@ -691,7 +693,8 @@ mext_replace_branches(handle_t *handle, struct inode *orig_inode,
/* Loop for the donor extents */
while (1) {
/* The extent for donor must be found. */
if (!dext) {
if (unlikely(!dext)) {
missing_donor_extent:
EXT4_ERROR_INODE(donor_inode,
"The extent for donor must be found");
*err = -EIO;