btrfs: make error messages more clear when getting a chunk map

When getting a chunk map, at btrfs_get_chunk_map(), we do some sanity
checks to verify we found a chunk map and that map found covers the
logical address the caller passed in. However the messages aren't very
clear in the sense that don't mention the issue is with a chunk map and
one of them prints the 'length' argument as if it were the end offset of
the requested range (while the in the string format we use %llu-%llu
which suggests a range, and the second %llu-%llu is actually a range for
the chunk map). So improve these two details in the error messages.

CC: stable@vger.kernel.org # 5.4+
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

fs/btrfs/volumes.c

@@ -3003,15 +3003,16 @@ struct extent_map *btrfs_get_chunk_map(struct btrfs_fs_info *fs_info,
 	read_unlock(&em_tree->lock);
 
 	if (!em) {
-		btrfs_crit(fs_info, "unable to find logical %llu length %llu",
+		btrfs_crit(fs_info,
+			   "unable to find chunk map for logical %llu length %llu",
 			   logical, length);
 		return ERR_PTR(-EINVAL);
 	}
 
 	if (em->start > logical || em->start + em->len <= logical) {
 		btrfs_crit(fs_info,
-			   "found a bad mapping, wanted %llu-%llu, found %llu-%llu",
-			   logical, length, em->start, em->start + em->len);
+			   "found a bad chunk map, wanted %llu-%llu, found %llu-%llu",
+			   logical, logical + length, em->start, em->start + em->len);
 		free_extent_map(em);
 		return ERR_PTR(-EINVAL);
 	}