Hello, So this is another case of "I lost my partition and do not have backups". More precisely, _this_ is the backup and it turned out to be damaged.
(The backup was made by partclone.btrfs. Together with a zeroed out tree root, this asks for a bug in partclone...) So: the tree root is zeroes, backup roots are zeroes too, btrfs-find-root only reports blocks of level 0 (needed is 1). Is there something that can be done? Maybe it is possible to reconstruct the root from its children? Operations log following. Please Cc: me in replies as I'm not subscribed to the list. 1. regular mount # mount /dev/loop0p3 /mnt/temp === dmesg === [106737.299592] BTRFS info (device loop0p3): disk space caching is enabled [106737.299604] BTRFS: has skinny extents [106737.299884] BTRFS error (device loop0p3): bad tree block start 0 162633449472 [106737.299888] BTRFS: failed to read tree root on loop0p3 [106737.314359] BTRFS: open_ctree failed === end dmesg === 2. mount with -o recovery # mount -o recovery /dev/loop0p3 /mnt/temp === dmesg === [106742.305720] BTRFS warning (device loop0p3): 'recovery' is deprecated, use 'usebackuproot' instead [106742.305722] BTRFS info (device loop0p3): trying to use backup root at mount time [106742.305724] BTRFS info (device loop0p3): disk space caching is enabled [106742.305725] BTRFS: has skinny extents [106742.306056] BTRFS error (device loop0p3): bad tree block start 0 162633449472 [106742.306060] BTRFS: failed to read tree root on loop0p3 [106742.306069] BTRFS error (device loop0p3): bad tree block start 0 162633449472 [106742.306071] BTRFS: failed to read tree root on loop0p3 [106742.306084] BTRFS error (device loop0p3): bad tree block start 0 162632237056 [106742.306086] BTRFS: failed to read tree root on loop0p3 [106742.306097] BTRFS error (device loop0p3): bad tree block start 0 162626682880 [106742.306100] BTRFS: failed to read tree root on loop0p3 [106742.306111] BTRFS error (device loop0p3): bad tree block start 0 162609168384 [106742.306114] BTRFS: failed to read tree root on loop0p3 [106742.327272] BTRFS: open_ctree failed === end dmesg === 3. btrfs-find-root # btrfs-find-root /dev/loop0p3 Couldn't read tree root Superblock thinks the generation is 22332 Superblock thinks the level is 1 Well block 162633646080(gen: 22332 level: 0) seems good, but generation/level doesn't match, want gen: 22332 level: 1 Well block 162633596928(gen: 22332 level: 0) seems good, but generation/level doesn't match, want gen: 22332 level: 1 Well block 162633515008(gen: 22332 level: 0) seems good, but generation/level doesn't match, want gen: 22332 level: 1 Thanks, -- Ivan Shapovalov / intelfx /
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