btrfs-progs: print-tree: Print offset as tree objectid for ROOT_ITEM

For cases like reloc trees and subvolume trees, their key offset is the
tree id.  The key will be printed as:

(TREE_RELOC ROOT_ITEM 18446744073709551607)

The negative number is long and even guys with real engineer brains
can't easily get the meaning.

This patch will change the output format to:

(TREE_RELOC ROOT_ITEM DATA_RELOC_TREE)

While for special offset value like 0 or (u64)-1, it's still shown as
is.

Signed-off-by: Qu Wenruo <wqu@suse.com>
[ reword comment ]
Signed-off-by: David Sterba <dsterba@suse.com>

diff --git a/print-tree.c b/print-tree.c
index 3c585e3..cee30bf 100644 (file)
--- a/print-tree.c
+++ b/print-tree.c
@@ -794,6 +794,17 @@ void btrfs_print_key(struct btrfs_disk_key *disk_key)
        case BTRFS_UUID_KEY_RECEIVED_SUBVOL:
                printf(" 0x%016llx)", (unsigned long long)offset);
                break;
+
+       /*
+        * Key offsets of ROOT_ITEM point to tree root, print them in human
+        * readable format.  Especially useful for trees like data/tree reloc
+        * tree, whose tree id can be negative.
+        */
+       case BTRFS_ROOT_ITEM_KEY:
+               printf(" ");
+               print_objectid(stdout, offset, type);
+               printf(")");
+               break;
        default:
                if (offset == (u64)-1)
                        printf(" -1)");