On Mon, Sep 24, 2012 at 6:12 PM, David Sterba <d...@jikos.cz> wrote: > On Mon, Sep 24, 2012 at 03:02:39PM +0100, Hugo Mills wrote: > > Out of interest, does mounting with -o recovery help at all? (I'm > > not expecting it to do much if your chunk tree's gone, but it might do > > something). > > The -o recovery has access to the respective tree roots, but the > contents may be destroyed already. The chunk tree is not deep, I can see > height 1 on a 6 disk array (though lightly used, 1 node, 8 leaves) and 3 > disk array (1/7 TB used, 1 node, 29 leaves). So it's quite a small > amount of data to destroy the chunktree completely, COW will lower the > chances a bit.
Yeah, the whole tree is gone, I'm pretty sure of it since the first 20-50GB has been wiped from the drive and the mentioned address is in the beginning of that part. I just wonder if there is any chance of the older versions of the chunk tree still being somewhere and how to find them. I doubt it's an easy feat though. > Rebuilding from scratch does not look simple, the available information > is stored in BLOCK_GROUP_ITEMs or INODE_ITEMs and covers portions of the > chunks. Given that the device tree would be probably damaged as well, > the amount of information to do cross-check is not high. Maybe replaying > the chunk creation logic can save some guesswork. Replaying chunk creation logic would not help that much, since the drive has been resized a few times and had other operations that have modified the chunk tree as well. The array itself is not that complex (2 drives), but it's still not as simple as a single drive array. Regards, -- Sami Haahtinen Bad Wolf Oy +358443302775 -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
