On 2017年12月31日 03:54, Stirling Westrup wrote: > 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.
The system is more damaged than your expectation. Tree root is also corrupted. Although I could make dump-tree to skip root tree, but even with hand crafted super, the corrupted tree root is still a big problem. Thanks, Qu > > > > 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 >
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