On Sat, Apr 15, 2017 at 12:14 AM, Andrei Borzenkov <[email protected]> wrote: > 12.04.2017 20:21, Chris Murphy пишет: >> btrfs-map-logical is the tool that will convert logical to physical >> and also give what device it's on; but the device notation is copy 1 >> and copy 2, so you have to infer what device that is, it's not >> explicit. >> > > Actually I just checked with btrfsprogs 4.5.3 on RAID5 and it does print > OS device name for each data chunk. It does not show checksum chunk for > RAID56 though.
There is no checksum chunk. The data csums are in their own tree, and only data is csum'd. The parity strip is contained within a raid56 chunk but is itself not csum'd. Another thing that I just thought of might be useful is btrfs-debugfs which is a python script in btrfs-progs, but typically not packaged. The -f option pointed at a file will show extents with Btrfs logical bytenr. So that'd be a way to get all the extents, their addresses and lengths, to then dump into btrfs-map-logical. For what it's worth, btrfs-map-logical's physical address it reports is not device LBA. It's a byte offset on the selected device. So if the device is a partition, the value is the number of bytes from the start of that partition. -- Chris Murphy -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
