ext4: avoid trying to kfree an ERR_PTR pointer

commit a9cfcd63 upstream.

Thanks to Dan Carpenter for extending smatch to find bugs like this.
(This was found using a development version of smatch.)

Fixes: 36de9286
Reported-by: Dan Carpenter <dan.carpenter@oracle.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
[lizf: Backported to 3.4:
- s/new.bh/new_bh/
- drop the change to ext4_cross_rename()]
Signed-off-by: Zefan Li <lizefan@huawei.com>

fs/ext4/namei.c

@@ -2452,6 +2452,7 @@ static int ext4_rename(struct inode *old_dir, struct dentry *old_dentry,
 	new_bh = ext4_find_entry(new_dir, &new_dentry->d_name, &new_de);
 	if (IS_ERR(new_bh)) {
 		retval = PTR_ERR(new_bh);
+		new_bh = NULL;
 		goto end_rename;
 	}
 	if (new_bh) {

fs/ext4/resize.c

@@ -528,6 +528,7 @@ static int setup_new_flex_group_blocks(struct super_block *sb,
 		bh = bclean(handle, sb, block);
 		if (IS_ERR(bh)) {
 			err = PTR_ERR(bh);
+			bh = NULL;
 			goto out;
 		}
 		if (ext4_bg_has_super(sb, group)) {
@@ -556,6 +557,7 @@ static int setup_new_flex_group_blocks(struct super_block *sb,
 		bh = bclean(handle, sb, block);
 		if (IS_ERR(bh)) {
 			err = PTR_ERR(bh);
+			bh = NULL;
 			goto out;
 		}