btrfs: don't rewrite ret from inode_permission

In our user safe ino resolve ioctl we'll just turn any ret into -EACCES
from inode_permission().  This is redundant, and could potentially be
wrong if we had an ENOMEM in the security layer or some such other
error, so simply return the actual return value.

Note: The patch was taken from v5 of fscrypt patchset
(https://lore.kernel.org/linux-btrfs/cover.1706116485.git.josef@toxicpanda.com/)
which was handled over time by various people: Omar Sandoval, Sweet Tea
Dorminy, Josef Bacik.

Fixes: 23d0b79 ("btrfs: Add unprivileged version of ino_lookup ioctl")
CC: stable@vger.kernel.org # 5.4+
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Daniel Vacek <neelx@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
[ add note ]
Signed-off-by: David Sterba <dsterba@suse.com>

Author: josefbacik

fs/btrfs/ioctl.c

@@ -1910,10 +1910,8 @@ static int btrfs_search_path_in_tree_user(struct mnt_idmap *idmap,
 			ret = inode_permission(idmap, &temp_inode->vfs_inode,
 					       MAY_READ | MAY_EXEC);
 			iput(&temp_inode->vfs_inode);
-			if (ret) {
-				ret = -EACCES;
+			if (ret)
 				goto out_put;
-			}
 
 			if (key.offset == upper_limit)
 				break;