On 2018年03月19日 18:46, Nikolay Borisov wrote:
>
>
> On 19.03.2018 12:28, Qu Wenruo wrote:
>> Commit Fixes: 8c36786c8198 ("btrfs-progs: print-tree: Print offset as tree objectid for ROOT_ITEM")
>> changes how we translate offset of ROOT_ITEM.
>>
>> However the fact is, even for ROOT_ITEM, we have different meaning of
>> offset.
>>
>> For tree reloc tree, it's indeed subvolume id.
>> But for other trees, it's the transid of when it's created.
>>
>> Fix it.
>>
>> Reported-by: Nikolay Borisov <nborisov@xxxxxxxx>
>> Signed-off-by: Qu Wenruo <wqu@xxxxxxxx>
>> ---
>> print-tree.c | 11 ++++++++++-
>> 1 file changed, 10 insertions(+), 1 deletion(-)
>>
>> diff --git a/print-tree.c b/print-tree.c
>> index 45350fea0963..848e296c4e67 100644
>> --- a/print-tree.c
>> +++ b/print-tree.c
>> @@ -834,7 +834,16 @@ void btrfs_print_key(struct btrfs_disk_key *disk_key)
>> */
>> case BTRFS_ROOT_ITEM_KEY:
>> printf(" ");
>> - print_objectid(stdout, offset, type);
>> + /*
>> + * Normally offset of ROOT_ITEM should presents the generation
>> + * when this root is created.
>> + * However if this is tree reloc tree, offset is the subvolume
>> + * id of its source. Here we do extra check on this.
>> + */
>> + if (objectid == BTRFS_TREE_RELOC_OBJECTID)
>> + print_objectid(stdout, offset, type);
>
> Do we even have to do this for the reloc tree. If the offset is just a
> numeric id tied to a subvolume then the only possible value different
> than a numerci value is FS_TREE (in case we have 5 as the source subvol)
> but even this is not very informative. I'd suggest just leaving it as a
> numeric value.
What about this value?
18446744073709551607
It's data reloc tree objectid.
And it's pretty long since it's -9ULL.
At least this makes 2 objectid more readable.
Thanks,
Qu
>
>> + else
>> + printf("%lld", offset);
>> printf(")");
>> break;
>> default:
>>
> --
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