Dear all, I had posted already (excuse for separate mails) that I have a corrupt filesystem that would be very important to get recovered. Please note I would really appreciate assistance and am willing to PAY for consultation and time. Kernel 4.20.17 btrfs-progs 4.20.2 The filesystem consists of 4 (HW raid6) devices, each of them shows different superblock backups but my hope is that backup 2 is "consistent" across all of them. Is there any way to restore a specific superblock backup and attempt to mount the filesystem? Running "btrfs restore" did partially recover the data, but the most important bit is still missing. See also how "generation" is different between devices 1,2 and 3,4. Please see below output of the different devices. My hope is that I can somehow "restore" the smallest common generation of superblock on 60232 to make the FS at least read-only mountable. ################# SDB ############ # btrfs inspect-internal dump-super -f /dev/sdb superblock: bytenr=65536, device=/dev/sdb --------------------------------------------------------- csum_type 0 (crc32c) csum_size 4 csum 0xebea13e2 [match] bytenr 65536 flags 0x1 ( WRITTEN ) magic _BHRfS_M [match] fsid 8b19ff46-3f42-4f51-be6b-5fc8a7d8f2cd metadata_uuid 8b19ff46-3f42-4f51-be6b-5fc8a7d8f2cd label FS1 generation 60233 root 55432745107456 sys_array_size 194 chunk_root_generation 60232 root_level 1 chunk_root 1146880 chunk_root_level 1 log_root 55432747958272 log_root_transid 0 log_root_level 0 total_bytes 95999901040640 bytes_used 60378125692928 sectorsize 4096 nodesize 16384 leafsize (deprecated) 16384 stripesize 4096 root_dir 6 num_devices 4 compat_flags 0x0 compat_ro_flags 0x3 ( FREE_SPACE_TREE | FREE_SPACE_TREE_VALID ) incompat_flags 0x161 ( MIXED_BACKREF | BIG_METADATA | EXTENDED_IREF | SKINNY_METADATA ) cache_generation 18446744073709551615 uuid_tree_generation 60233 dev_item.uuid 7833ce66-ffa3-4baa-a2db-e98d5ec2e369 dev_item.fsid 8b19ff46-3f42-4f51-be6b-5fc8a7d8f2cd [match] dev_item.type 0 dev_item.total_bytes 23999975260160 dev_item.bytes_used 15122592432128 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 1048576) length 4194304 owner 2 stripe_len 65536 type SYSTEM io_align 4096 io_width 4096 sector_size 4096 num_stripes 1 sub_stripes 0 stripe 0 devid 1 offset 1048576 dev_uuid 7833ce66-ffa3-4baa-a2db-e98d5ec2e369 item 1 key (FIRST_CHUNK_TREE CHUNK_ITEM 60713713270784) length 33554432 owner 2 stripe_len 65536 type SYSTEM io_align 65536 io_width 65536 sector_size 4096 num_stripes 1 sub_stripes 1 stripe 0 devid 2 offset 15033460326400 dev_uuid bb5e99fe-3beb-44f3-a6e0-43395ddfcd84 backup_roots[4]: backup 0: backup_tree_root: 55432745107456 gen: 60233 level: 1 backup_chunk_root: 1146880 gen: 60232 level: 1 backup_extent_root: 55432763981824 gen: 60233 level: 3 backup_fs_root: 55432763850752 gen: 60233 level: 2 backup_dev_root: 55432753725440 gen: 60232 level: 1 backup_csum_root: 55432764342272 gen: 60233 level: 0 backup_total_bytes: 95999901040640 backup_bytes_used: 60378125692928 backup_num_devices: 4 backup 1: backup_tree_root: 55432755216384 gen: 60230 level: 1 backup_chunk_root: 1048576 gen: 60230 level: 1 backup_extent_root: 55432754511872 gen: 60230 level: 3 backup_fs_root: 55432756281344 gen: 60231 level: 2 backup_dev_root: 55432755625984 gen: 60230 level: 1 backup_csum_root: 55432750727168 gen: 60230 level: 0 backup_total_bytes: 95999901040640 backup_bytes_used: 60372281278464 backup_num_devices: 4 backup 2: backup_tree_root: 55432746385408 gen: 60231 level: 1 backup_chunk_root: 1048576 gen: 60230 level: 1 backup_extent_root: 55432738242560 gen: 60231 level: 3 backup_fs_root: 55432756281344 gen: 60231 level: 2 backup_dev_root: 55432755625984 gen: 60230 level: 1 backup_csum_root: 55432750727168 gen: 60230 level: 0 backup_total_bytes: 95999901040640 backup_bytes_used: 60372283375616 backup_num_devices: 4 backup 3: backup_tree_root: 55432763015168 gen: 60232 level: 1 backup_chunk_root: 1146880 gen: 60232 level: 1 backup_extent_root: 55432763981824 gen: 60233 level: 3 backup_fs_root: 55432763850752 gen: 60233 level: 2 backup_dev_root: 55432753725440 gen: 60232 level: 1 backup_csum_root: 55432764342272 gen: 60233 level: 0 backup_total_bytes: 95999901040640 backup_bytes_used: 60378125692928 backup_num_devices: 4 ########### SDC ############ btrfs inspect-internal dump-super -f /dev/sdc superblock: bytenr=65536, device=/dev/sdc --------------------------------------------------------- csum_type 0 (crc32c) csum_size 4 csum 0x310a7e9a [match] bytenr 65536 flags 0x1 ( WRITTEN ) magic _BHRfS_M [match] fsid 8b19ff46-3f42-4f51-be6b-5fc8a7d8f2cd metadata_uuid 8b19ff46-3f42-4f51-be6b-5fc8a7d8f2cd label FS1 generation 60233 root 55432745107456 sys_array_size 194 chunk_root_generation 60232 root_level 1 chunk_root 1146880 chunk_root_level 1 log_root 55432747958272 log_root_transid 0 log_root_level 0 total_bytes 95999901040640 bytes_used 60378125692928 sectorsize 4096 nodesize 16384 leafsize (deprecated) 16384 stripesize 4096 root_dir 6 num_devices 4 compat_flags 0x0 compat_ro_flags 0x3 ( FREE_SPACE_TREE | FREE_SPACE_TREE_VALID ) incompat_flags 0x161 ( MIXED_BACKREF | BIG_METADATA | EXTENDED_IREF | SKINNY_METADATA ) cache_generation 18446744073709551615 uuid_tree_generation 60233 dev_item.uuid bb5e99fe-3beb-44f3-a6e0-43395ddfcd84 dev_item.fsid 8b19ff46-3f42-4f51-be6b-5fc8a7d8f2cd [match] dev_item.type 0 dev_item.total_bytes 23999975260160 dev_item.bytes_used 15122613403648 dev_item.io_align 4096 dev_item.io_width 4096 dev_item.sector_size 4096 dev_item.devid 2 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 1048576) length 4194304 owner 2 stripe_len 65536 type SYSTEM io_align 4096 io_width 4096 sector_size 4096 num_stripes 1 sub_stripes 0 stripe 0 devid 1 offset 1048576 dev_uuid 7833ce66-ffa3-4baa-a2db-e98d5ec2e369 item 1 key (FIRST_CHUNK_TREE CHUNK_ITEM 60713713270784) length 33554432 owner 2 stripe_len 65536 type SYSTEM io_align 65536 io_width 65536 sector_size 4096 num_stripes 1 sub_stripes 1 stripe 0 devid 2 offset 15033460326400 dev_uuid bb5e99fe-3beb-44f3-a6e0-43395ddfcd84 backup_roots[4]: backup 0: backup_tree_root: 55432745107456 gen: 60233 level: 1 backup_chunk_root: 1146880 gen: 60232 level: 1 backup_extent_root: 55432763981824 gen: 60233 level: 3 backup_fs_root: 55432763850752 gen: 60233 level: 2 backup_dev_root: 55432753725440 gen: 60232 level: 1 backup_csum_root: 55432764342272 gen: 60233 level: 0 backup_total_bytes: 95999901040640 backup_bytes_used: 60378125692928 backup_num_devices: 4 backup 1: backup_tree_root: 55432755216384 gen: 60230 level: 1 backup_chunk_root: 1048576 gen: 60230 level: 1 backup_extent_root: 55432754511872 gen: 60230 level: 3 backup_fs_root: 55432756281344 gen: 60231 level: 2 backup_dev_root: 55432755625984 gen: 60230 level: 1 backup_csum_root: 55432750727168 gen: 60230 level: 0 backup_total_bytes: 95999901040640 backup_bytes_used: 60372281278464 backup_num_devices: 4 backup 2: backup_tree_root: 55432746385408 gen: 60231 level: 1 backup_chunk_root: 1048576 gen: 60230 level: 1 backup_extent_root: 55432738242560 gen: 60231 level: 3 backup_fs_root: 55432756281344 gen: 60231 level: 2 backup_dev_root: 55432755625984 gen: 60230 level: 1 backup_csum_root: 55432750727168 gen: 60230 level: 0 backup_total_bytes: 95999901040640 backup_bytes_used: 60372283375616 backup_num_devices: 4 backup 3: backup_tree_root: 55432763015168 gen: 60232 level: 1 backup_chunk_root: 1146880 gen: 60232 level: 1 backup_extent_root: 55432763981824 gen: 60233 level: 3 backup_fs_root: 55432763850752 gen: 60233 level: 2 backup_dev_root: 55432753725440 gen: 60232 level: 1 backup_csum_root: 55432764342272 gen: 60233 level: 0 backup_total_bytes: 95999901040640 backup_bytes_used: 60378125692928 backup_num_devices: 4 ########### SDD ########## btrfs inspect-internal dump-super -f /dev/sdd superblock: bytenr=65536, device=/dev/sdd --------------------------------------------------------- csum_type 0 (crc32c) csum_size 4 csum 0x56f1abb4 [match] bytenr 65536 flags 0x1 ( WRITTEN ) magic _BHRfS_M [match] fsid 8b19ff46-3f42-4f51-be6b-5fc8a7d8f2cd metadata_uuid 8b19ff46-3f42-4f51-be6b-5fc8a7d8f2cd label FS1 generation 60234 root 55432766062592 sys_array_size 194 chunk_root_generation 60234 root_level 1 chunk_root 1048576 chunk_root_level 1 log_root 0 log_root_transid 0 log_root_level 0 total_bytes 95999901040640 bytes_used 60382615777280 sectorsize 4096 nodesize 16384 leafsize (deprecated) 16384 stripesize 4096 root_dir 6 num_devices 4 compat_flags 0x0 compat_ro_flags 0x3 ( FREE_SPACE_TREE | FREE_SPACE_TREE_VALID ) incompat_flags 0x161 ( MIXED_BACKREF | BIG_METADATA | EXTENDED_IREF | SKINNY_METADATA ) cache_generation 18446744073709551615 uuid_tree_generation 60234 dev_item.uuid cc6e5f1c-081c-441f-9634-6908164e1375 dev_item.fsid 8b19ff46-3f42-4f51-be6b-5fc8a7d8f2cd [match] dev_item.type 0 dev_item.total_bytes 23999975260160 dev_item.bytes_used 15123653591040 dev_item.io_align 4096 dev_item.io_width 4096 dev_item.sector_size 4096 dev_item.devid 3 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 1048576) length 4194304 owner 2 stripe_len 65536 type SYSTEM io_align 4096 io_width 4096 sector_size 4096 num_stripes 1 sub_stripes 0 stripe 0 devid 1 offset 1048576 dev_uuid 7833ce66-ffa3-4baa-a2db-e98d5ec2e369 item 1 key (FIRST_CHUNK_TREE CHUNK_ITEM 60713713270784) length 33554432 owner 2 stripe_len 65536 type SYSTEM io_align 65536 io_width 65536 sector_size 4096 num_stripes 1 sub_stripes 1 stripe 0 devid 2 offset 15033460326400 dev_uuid bb5e99fe-3beb-44f3-a6e0-43395ddfcd84 backup_roots[4]: backup 0: backup_tree_root: 55432745107456 gen: 60233 level: 1 backup_chunk_root: 1146880 gen: 60232 level: 1 backup_extent_root: 55432763981824 gen: 60233 level: 3 backup_fs_root: 55432763850752 gen: 60233 level: 2 backup_dev_root: 55432753725440 gen: 60232 level: 1 backup_csum_root: 55432764342272 gen: 60233 level: 0 backup_total_bytes: 95999901040640 backup_bytes_used: 60378125692928 backup_num_devices: 4 backup 1: backup_tree_root: 55432766062592 gen: 60234 level: 1 backup_chunk_root: 1048576 gen: 60234 level: 1 backup_extent_root: 55432746352640 gen: 60234 level: 3 backup_fs_root: 55432763850752 gen: 60233 level: 2 backup_dev_root: 55432755789824 gen: 60234 level: 1 backup_csum_root: 55432764342272 gen: 60233 level: 0 backup_total_bytes: 95999901040640 backup_bytes_used: 60382615777280 backup_num_devices: 4 backup 2: backup_tree_root: 55432746385408 gen: 60231 level: 1 backup_chunk_root: 1048576 gen: 60230 level: 1 backup_extent_root: 55432738242560 gen: 60231 level: 3 backup_fs_root: 55432756281344 gen: 60231 level: 2 backup_dev_root: 55432755625984 gen: 60230 level: 1 backup_csum_root: 55432750727168 gen: 60230 level: 0 backup_total_bytes: 95999901040640 backup_bytes_used: 60372283375616 backup_num_devices: 4 backup 3: backup_tree_root: 55432763015168 gen: 60232 level: 1 backup_chunk_root: 1146880 gen: 60232 level: 1 backup_extent_root: 55432763981824 gen: 60233 level: 3 backup_fs_root: 55432763850752 gen: 60233 level: 2 backup_dev_root: 55432753725440 gen: 60232 level: 1 backup_csum_root: 55432764342272 gen: 60233 level: 0 backup_total_bytes: 95999901040640 backup_bytes_used: 60378125692928 backup_num_devices: 4 ####### SDE ####### btrfs inspect-internal dump-super -f /dev/sde superblock: bytenr=65536, device=/dev/sde --------------------------------------------------------- csum_type 0 (crc32c) csum_size 4 csum 0x6fcc7a25 [match] bytenr 65536 flags 0x1 ( WRITTEN ) magic _BHRfS_M [match] fsid 8b19ff46-3f42-4f51-be6b-5fc8a7d8f2cd metadata_uuid 8b19ff46-3f42-4f51-be6b-5fc8a7d8f2cd label FS1 generation 60234 root 55432766062592 sys_array_size 194 chunk_root_generation 60234 root_level 1 chunk_root 1048576 chunk_root_level 1 log_root 0 log_root_transid 0 log_root_level 0 total_bytes 95999901040640 bytes_used 60382615777280 sectorsize 4096 nodesize 16384 leafsize (deprecated) 16384 stripesize 4096 root_dir 6 num_devices 4 compat_flags 0x0 compat_ro_flags 0x3 ( FREE_SPACE_TREE | FREE_SPACE_TREE_VALID ) incompat_flags 0x161 ( MIXED_BACKREF | BIG_METADATA | EXTENDED_IREF | SKINNY_METADATA ) cache_generation 18446744073709551615 uuid_tree_generation 60234 dev_item.uuid d97063ad-078a-44b5-ae47-4f0f9f9755f9 dev_item.fsid 8b19ff46-3f42-4f51-be6b-5fc8a7d8f2cd [match] dev_item.type 0 dev_item.total_bytes 23999975260160 dev_item.bytes_used 15123653591040 dev_item.io_align 4096 dev_item.io_width 4096 dev_item.sector_size 4096 dev_item.devid 4 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 1048576) length 4194304 owner 2 stripe_len 65536 type SYSTEM io_align 4096 io_width 4096 sector_size 4096 num_stripes 1 sub_stripes 0 stripe 0 devid 1 offset 1048576 dev_uuid 7833ce66-ffa3-4baa-a2db-e98d5ec2e369 item 1 key (FIRST_CHUNK_TREE CHUNK_ITEM 60713713270784) length 33554432 owner 2 stripe_len 65536 type SYSTEM io_align 65536 io_width 65536 sector_size 4096 num_stripes 1 sub_stripes 1 stripe 0 devid 2 offset 15033460326400 dev_uuid bb5e99fe-3beb-44f3-a6e0-43395ddfcd84 backup_roots[4]: backup 0: backup_tree_root: 55432745107456 gen: 60233 level: 1 backup_chunk_root: 1146880 gen: 60232 level: 1 backup_extent_root: 55432763981824 gen: 60233 level: 3 backup_fs_root: 55432763850752 gen: 60233 level: 2 backup_dev_root: 55432753725440 gen: 60232 level: 1 backup_csum_root: 55432764342272 gen: 60233 level: 0 backup_total_bytes: 95999901040640 backup_bytes_used: 60378125692928 backup_num_devices: 4 backup 1: backup_tree_root: 55432766062592 gen: 60234 level: 1 backup_chunk_root: 1048576 gen: 60234 level: 1 backup_extent_root: 55432746352640 gen: 60234 level: 3 backup_fs_root: 55432763850752 gen: 60233 level: 2 backup_dev_root: 55432755789824 gen: 60234 level: 1 backup_csum_root: 55432764342272 gen: 60233 level: 0 backup_total_bytes: 95999901040640 backup_bytes_used: 60382615777280 backup_num_devices: 4 backup 2: backup_tree_root: 55432746385408 gen: 60231 level: 1 backup_chunk_root: 1048576 gen: 60230 level: 1 backup_extent_root: 55432738242560 gen: 60231 level: 3 backup_fs_root: 55432756281344 gen: 60231 level: 2 backup_dev_root: 55432755625984 gen: 60230 level: 1 backup_csum_root: 55432750727168 gen: 60230 level: 0 backup_total_bytes: 95999901040640 backup_bytes_used: 60372283375616 backup_num_devices: 4 backup 3: backup_tree_root: 55432763015168 gen: 60232 level: 1 backup_chunk_root: 1146880 gen: 60232 level: 1 backup_extent_root: 55432763981824 gen: 60233 level: 3 backup_fs_root: 55432763850752 gen: 60233 level: 2 backup_dev_root: 55432753725440 gen: 60232 level: 1 backup_csum_root: 55432764342272 gen: 60233 level: 0 backup_total_bytes: 95999901040640 backup_bytes_used: 60378125692928 backup_num_devices: 4 ###########################
