btrfs: fix uninitialized pointer free on read_alloc_one_name() error

The function read_alloc_one_name() does not initialize the name field of
the passed fscrypt_str struct if kmalloc fails to allocate the
corresponding buffer.  Thus, it is not guaranteed that
fscrypt_str.name is initialized when freeing it.

This is a follow-up to the linked patch that fixes the remaining
instances of the bug introduced by commit e43eec8 ("btrfs: use
struct qstr instead of name and namelen pairs").

Link: https://lore.kernel.org/linux-btrfs/20241009080833.1355894-1-jroi.martin@gmail.com/
Fixes: e43eec8 ("btrfs: use struct qstr instead of name and namelen pairs")
CC: stable@vger.kernel.org # 6.1+
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: Roi Martin <jroi.martin@gmail.com>
Signed-off-by: David Sterba <dsterba@suse.com>

fs/btrfs/tree-log.c

@@ -1845,7 +1845,7 @@ static noinline int replay_one_name(struct btrfs_trans_handle *trans,
 				    struct btrfs_dir_item *di,
 				    struct btrfs_key *key)
 {
-	struct fscrypt_str name;
+	struct fscrypt_str name = { 0 };
 	struct btrfs_dir_item *dir_dst_di;
 	struct btrfs_dir_item *index_dst_di;
 	bool dir_dst_matches = false;
@@ -2125,7 +2125,7 @@ static noinline int check_item_in_log(struct btrfs_trans_handle *trans,
 	struct extent_buffer *eb;
 	int slot;
 	struct btrfs_dir_item *di;
-	struct fscrypt_str name;
+	struct fscrypt_str name = { 0 };
 	struct inode *inode = NULL;
 	struct btrfs_key location;