Okay, so I've gone back to your earlier suggestion of dumping the chunk tree to get info for rebuiling a superblock by hand, but its not working.
/usr/local/bin/btrfs ins dump-tree -t chunk /dev/sdc btrfs-progs v4.14 bytenr mismatch, want=294191104, have=314114048 Couldn't read tree root ERROR: unable to open /dev/sdc I get the exact same error (except for device name) for every valid device in the FS. On Thu, Dec 28, 2017 at 9:08 PM, Qu Wenruo <quwenruo.bt...@gmx.com> wrote: > > > > Yes, this means you could get the needed device UUID and hand craft a > superblock. > But I really doubt about the possibility to success. > > If you really want to do that, there is needed steps for you: > > 1) Get device info from your existing fs > # btrfs ins dump-tree -t chunk </dev/sda> > And looking for the following thing: > ------ > item 1 key (DEV_ITEMS DEV_ITEM 2) itemoff 16185 itemsize 98 > devid 2 total_bytes 10737418240 bytes_used 289406976 > io_align 4096 io_width 4096 sector_size 4096 type 0 > generation 0 start_offset 0 dev_group 0 > seek_speed 0 bandwidth 0 > uuid f1d9b288-7865-463f-a65c-ca8b1fbde09b > fsid 1dd513fb-45f8-404f-ae23-979e3acb78ad > ------ > Look for the key (DEV_ITEMS DEV_ITEM 2) and grab the "uuid" > "total_bytes" "bytes_used" (other fields are mostly fixed) > > 2) Fill the fields of dev_item of a good superblock. > If you feel it hard, I could help to do it if you provide the binary > dump of any valid superblock, with above tree dump info. > -- 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
