On 31.10.2018 at 01:03 Qu Wenruo wrote: > My plan for such recovery is: > > 1) btrfs ins dump-super to make sure system chunk array is valid > 2) btrfs-find-root to find any valid chunk tree blocks > 3) pass that chunk tree bytenr to btrfs-restore > Unfortunately, btrfs-restore doesn't support specifying chunk root > yet. But it's pretty easy to add such support. > > So, please provide the "btrfs ins dump-super -Ffa" output to start with. Following your plan, I did 1) and 2). As 2) failed (see below), is there anything I can do to find the tree bytenr to supply btrfs-restore with it?
1) Here's the output given by "btrfs-show-super -Ffa": superblock: bytenr=65536, device=sdcard.iso --------------------------------------------------------- csum 0xb8e15dd7 [match] bytenr 65536 flags 0x1 ( WRITTEN ) magic _BHRfS_M [match] fsid 4235aa4f-7721-4e73-97f0-7fe0e9a3ce9c label generation 1757933 root 889143296 sys_array_size 226 chunk_root_generation 932006 root_level 0 chunk_root 20987904 chunk_root_level 0 log_root 890109952 log_root_transid 0 log_root_level 0 total_bytes 30666653696 bytes_used 16937803776 sectorsize 4096 nodesize 16384 leafsize 16384 stripesize 4096 root_dir 6 num_devices 1 compat_flags 0x0 compat_ro_flags 0x0 incompat_flags 0x61 ( MIXED_BACKREF | BIG_METADATA | EXTENDED_IREF ) csum_type 0 csum_size 4 cache_generation 1757933 uuid_tree_generation 149 dev_item.uuid 90185cf6-b937-49bb-b191-91d08677ee22 dev_item.fsid 4235aa4f-7721-4e73-97f0-7fe0e9a3ce9c [match] dev_item.type 0 dev_item.total_bytes 30666653696 dev_item.bytes_used 30666653696 dev_item.io_align 4096 dev_item.io_width 4096 dev_item.sector_size 4096 dev_item.devid 1 dev_item.dev_group 0 dev_item.seek_speed 0 dev_item.bandwidth 0 dev_item.generation 0 sys_chunk_array[2048]: item 0 key (FIRST_CHUNK_TREE CHUNK_ITEM 0) chunk length 4194304 owner 2 stripe_len 65536 type SYSTEM num_stripes 1 stripe 0 devid 1 offset 0 dev uuid: 90185cf6-b937-49bb-b191-91d08677ee22 item 1 key (FIRST_CHUNK_TREE CHUNK_ITEM 20971520) chunk length 8388608 owner 2 stripe_len 65536 type SYSTEM|DUP num_stripes 2 stripe 0 devid 1 offset 20971520 dev uuid: 90185cf6-b937-49bb-b191-91d08677ee22 stripe 1 devid 1 offset 29360128 dev uuid: 90185cf6-b937-49bb-b191-91d08677ee22 backup_roots[4]: backup 0: backup_tree_root: 889143296 gen: 1757933 level: 0 backup_chunk_root: 20987904 gen: 932006 level: 0 backup_extent_root: 888881152 gen: 1757933 level: 2 backup_fs_root: 889716736 gen: 1757934 level: 2 backup_dev_root: 307560448 gen: 1673227 level: 0 backup_csum_root: 887898112 gen: 1757934 level: 2 backup_total_bytes: 30666653696 backup_bytes_used: 16937803776 backup_num_devices: 1 backup 1: backup_tree_root: 882311168 gen: 1757930 level: 0 backup_chunk_root: 20987904 gen: 932006 level: 0 backup_extent_root: 879738880 gen: 1757931 level: 2 backup_fs_root: 883097600 gen: 1757931 level: 2 backup_dev_root: 307560448 gen: 1673227 level: 0 backup_csum_root: 883212288 gen: 1757931 level: 2 backup_total_bytes: 30666653696 backup_bytes_used: 16943640576 backup_num_devices: 1 backup 2: backup_tree_root: 881082368 gen: 1757931 level: 0 backup_chunk_root: 20987904 gen: 932006 level: 0 backup_extent_root: 879738880 gen: 1757931 level: 2 backup_fs_root: 883654656 gen: 1757932 level: 2 backup_dev_root: 307560448 gen: 1673227 level: 0 backup_csum_root: 883703808 gen: 1757932 level: 2 backup_total_bytes: 30666653696 backup_bytes_used: 16943722496 backup_num_devices: 1 backup 3: backup_tree_root: 887865344 gen: 1757932 level: 0 backup_chunk_root: 20987904 gen: 932006 level: 0 backup_extent_root: 888881152 gen: 1757933 level: 2 backup_fs_root: 888750080 gen: 1757933 level: 2 backup_dev_root: 307560448 gen: 1673227 level: 0 backup_csum_root: 888832000 gen: 1757933 level: 2 backup_total_bytes: 30666653696 backup_bytes_used: 16937803776 backup_num_devices: 1 superblock: bytenr=67108864, device=sdcard.iso --------------------------------------------------------- csum 0x00000000 [DON'T MATCH] bytenr 0 flags 0x0 magic ........ [DON'T MATCH] fsid 00000000-0000-0000-0000-000000000000 label generation 0 root 0 sys_array_size 0 chunk_root_generation 0 root_level 0 chunk_root 0 chunk_root_level 0 log_root 0 log_root_transid 0 log_root_level 0 total_bytes 0 bytes_used 0 sectorsize 0 nodesize 0 leafsize 0 stripesize 0 root_dir 0 num_devices 0 compat_flags 0x0 compat_ro_flags 0x0 incompat_flags 0x0 csum_type 0 csum_size 4 cache_generation 0 uuid_tree_generation 0 dev_item.uuid 00000000-0000-0000-0000-000000000000 dev_item.fsid 00000000-0000-0000-0000-000000000000 [match] dev_item.type 0 dev_item.total_bytes 0 dev_item.bytes_used 0 dev_item.io_align 0 dev_item.io_width 0 dev_item.sector_size 0 dev_item.devid 0 dev_item.dev_group 0 dev_item.seek_speed 0 dev_item.bandwidth 0 dev_item.generation 0 sys_chunk_array[2048]: backup_roots[4]: 2) "btrfs-find-root" yields "Couldn't read chunk root; Open ctree failed". > Thanks, > Qu Thank you for your quick response and help. -- Mirko
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