ext4: avoid trying to kfree an ERR_PTR pointer

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

Fixes: 36de928641
Reported-by: Dan Carpenter <dan.carpenter@oracle.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Cc: stable@vger.kernel.org

fs/ext4/namei.c

@@ -3240,6 +3240,7 @@ static int ext4_rename(struct inode *old_dir, struct dentry *old_dentry,
 				 &new.de, &new.inlined);
 	if (IS_ERR(new.bh)) {
 		retval = PTR_ERR(new.bh);
+		new.bh = NULL;
 		goto end_rename;
 	}
 	if (new.bh) {
@@ -3386,6 +3387,7 @@ static int ext4_cross_rename(struct inode *old_dir, struct dentry *old_dentry,
 				 &new.de, &new.inlined);
 	if (IS_ERR(new.bh)) {
 		retval = PTR_ERR(new.bh);
+		new.bh = NULL;
 		goto end_rename;
 	}
 

fs/ext4/resize.c

@@ -575,6 +575,7 @@ handle_bb:
 		bh = bclean(handle, sb, block);
 		if (IS_ERR(bh)) {
 			err = PTR_ERR(bh);
+			bh = NULL;
 			goto out;
 		}
 		overhead = ext4_group_overhead_blocks(sb, group);
@@ -603,6 +604,7 @@ handle_ib:
 		bh = bclean(handle, sb, block);
 		if (IS_ERR(bh)) {
 			err = PTR_ERR(bh);
+			bh = NULL;
 			goto out;
 		}