On Mon, Aug 3, 2015 at 1:17 AM, Duncan <1i5t5.dun...@cox.net> wrote: > The first thing you need to do in terms of trying to recover, is restore > the superblock on the damaged device. Since btrfs keeps multiple copies > (up to three, once the filesystem is large enough, as yours is) per > device, that's actually relatively easy. Use... > > btrfs rescue super-recover
Not sure how to tell if there is a superblock issue: =============================== btrfs-show-super -f /dev/sdc superblock: bytenr=65536, device=/dev/sdc --------------------------------------------------------- dev_item.type 0 dev_item.total_bytes 4000787030016 dev_item.bytes_used 3527267057664 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 20971520) chunk length 16777216 owner 2 type SYSTEM|RAID0 num_stripes 2 stripe 0 devid 2 offset 1048576 stripe 1 devid 1 offset 20971520 backup_roots[4]: backup 0: backup_tree_root: 1517037699072 gen: 9025 level: 1 backup_chunk_root: 20971520 gen: 8957 level: 1 backup_extent_root: 576585728 gen: 9025 level: 2 backup_fs_root: 2056568832 gen: 1106 level: 0 backup_dev_root: 52576256 gen: 9021 level: 1 backup_csum_root: 1517028753408 gen: 9025 level: 3 backup_total_bytes: 8001574060032 backup_bytes_used: 7038625824768 backup_num_devices: 2 backup 1: backup_tree_root: 1517167755264 gen: 9026 level: 1 backup_chunk_root: 20971520 gen: 8957 level: 1 backup_extent_root: 1517167771648 gen: 9026 level: 2 backup_fs_root: 2056568832 gen: 1106 level: 0 backup_dev_root: 52576256 gen: 9021 level: 1 backup_csum_root: 2503711637504 gen: 9026 level: 3 backup_total_bytes: 8001574060032 backup_bytes_used: 7038625824768 backup_num_devices: 2 backup 2: backup_tree_root: 980877312 gen: 9023 level: 1 backup_chunk_root: 20971520 gen: 8957 level: 1 backup_extent_root: 1026768896 gen: 9023 level: 2 backup_fs_root: 2056568832 gen: 1106 level: 0 backup_dev_root: 52576256 gen: 9021 level: 1 backup_csum_root: 1790377984 gen: 9023 level: 3 backup_total_bytes: 8001574060032 backup_bytes_used: 7038617616384 backup_num_devices: 2 backup 3: backup_tree_root: 1960509440 gen: 9024 level: 1 backup_chunk_root: 20971520 gen: 8957 level: 1 backup_extent_root: 1960525824 gen: 9024 level: 2 backup_fs_root: 2056568832 gen: 1106 level: 0 backup_dev_root: 52576256 gen: 9021 level: 1 backup_csum_root: 2106736640 gen: 9024 level: 3 backup_total_bytes: 8001574060032 backup_bytes_used: 7038617616384 backup_num_devices: 2 btrfs-show-super -f /dev/sde superblock: bytenr=65536, device=/dev/sde --------------------------------------------------------- csum 0x9634c164 [match] bytenr 65536 flags 0x1 ( WRITTEN ) magic _BHRfS_M [match] fsid 09024c28-7932-4ddb-960d-becc1ea839e5 label terrafirm generation 9026 root 1517167755264 sys_array_size 129 chunk_root_generation 8957 root_level 1 chunk_root 20971520 chunk_root_level 1 log_root 0 log_root_transid 0 log_root_level 0 total_bytes 8001574060032 bytes_used 7038625824768 sectorsize 4096 nodesize 16384 leafsize 16384 stripesize 4096 root_dir 6 num_devices 2 compat_flags 0x0 compat_ro_flags 0x0 incompat_flags 0x21 ( MIXED_BACKREF | BIG_METADATA ) csum_type 0 csum_size 4 cache_generation 9026 uuid_tree_generation 9026 dev_item.uuid d63b1c46-b5a2-49ae-861f-804b2f97f427 dev_item.fsid 09024c28-7932-4ddb-960d-becc1ea839e5 [match] dev_item.type 0 dev_item.total_bytes 4000787030016 dev_item.bytes_used 3527250280448 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 20971520) chunk length 16777216 owner 2 type SYSTEM|RAID0 num_stripes 2 stripe 0 devid 2 offset 1048576 stripe 1 devid 1 offset 20971520 backup_roots[4]: backup 0: backup_tree_root: 1517037699072 gen: 9025 level: 1 backup_chunk_root: 20971520 gen: 8957 level: 1 backup_extent_root: 576585728 gen: 9025 level: 2 backup_fs_root: 2056568832 gen: 1106 level: 0 backup_dev_root: 52576256 gen: 9021 level: 1 backup_csum_root: 1517028753408 gen: 9025 level: 3 backup_total_bytes: 8001574060032 backup_bytes_used: 7038625824768 backup_num_devices: 2 backup 1: backup_tree_root: 1517167755264 gen: 9026 level: 1 backup_chunk_root: 20971520 gen: 8957 level: 1 backup_extent_root: 1517167771648 gen: 9026 level: 2 backup_fs_root: 2056568832 gen: 1106 level: 0 backup_dev_root: 52576256 gen: 9021 level: 1 backup_csum_root: 2503711637504 gen: 9026 level: 3 backup_total_bytes: 8001574060032 backup_bytes_used: 7038625824768 backup_num_devices: 2 backup 2: backup_tree_root: 980877312 gen: 9023 level: 1 backup_chunk_root: 20971520 gen: 8957 level: 1 backup_extent_root: 1026768896 gen: 9023 level: 2 backup_fs_root: 2056568832 gen: 1106 level: 0 backup_dev_root: 52576256 gen: 9021 level: 1 backup_csum_root: 1790377984 gen: 9023 level: 3 backup_total_bytes: 8001574060032 backup_bytes_used: 7038617616384 backup_num_devices: 2 backup 3: backup_tree_root: 1960509440 gen: 9024 level: 1 backup_chunk_root: 20971520 gen: 8957 level: 1 backup_extent_root: 1960525824 gen: 9024 level: 2 backup_fs_root: 2056568832 gen: 1106 level: 0 backup_dev_root: 52576256 gen: 9021 level: 1 backup_csum_root: 2106736640 gen: 9024 level: 3 backup_total_bytes: 8001574060032 backup_bytes_used: 7038617616384 backup_num_devices: 2 btrfs-show-super -a /dev/sdc superblock: bytenr=65536, device=/dev/sdc --------------------------------------------------------- csum 0x510e90f6 [match] bytenr 65536 flags 0x1 ( WRITTEN ) magic _BHRfS_M [match] fsid 09024c28-7932-4ddb-960d-becc1ea839e5 label terrafirm generation 9026 root 1517167755264 sys_array_size 129 chunk_root_generation 8957 root_level 1 chunk_root 20971520 chunk_root_level 1 log_root 0 log_root_transid 0 log_root_level 0 total_bytes 8001574060032 bytes_used 7038625824768 sectorsize 4096 nodesize 16384 leafsize 16384 stripesize 4096 root_dir 6 num_devices 2 compat_flags 0x0 compat_ro_flags 0x0 incompat_flags 0x21 ( MIXED_BACKREF | BIG_METADATA ) csum_type 0 csum_size 4 cache_generation 9026 uuid_tree_generation 9026 dev_item.uuid 224c95e6-d71b-494a-a4f6-cc72a84f1e89 dev_item.fsid 09024c28-7932-4ddb-960d-becc1ea839e5 [match] dev_item.type 0 dev_item.total_bytes 4000787030016 dev_item.bytes_used 3527267057664 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 superblock: bytenr=67108864, device=/dev/sdc --------------------------------------------------------- csum 0xf16fb838 [match] bytenr 67108864 flags 0x1 ( WRITTEN ) magic _BHRfS_M [match] fsid 09024c28-7932-4ddb-960d-becc1ea839e5 label terrafirm generation 9026 root 1517167755264 sys_array_size 129 dev_item.type 0 dev_item.total_bytes 4000787030016 dev_item.bytes_used 3527267057664 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 superblock: bytenr=274877906944, device=/dev/sdc --------------------------------------------------------- csum 0x0ce8ee09 [match] bytenr 274877906944 flags 0x1 ( WRITTEN ) magic _BHRfS_M [match] fsid 09024c28-7932-4ddb-960d-becc1ea839e5 label terrafirm generation 9026 root 1517167755264 sys_array_size 129 chunk_root_generation 8957 root_level 1 chunk_root 20971520 chunk_root_level 1 log_root 0 log_root_transid 0 log_root_level 0 total_bytes 8001574060032 bytes_used 7038625824768 sectorsize 4096 nodesize 16384 leafsize 16384 stripesize 4096 root_dir 6 num_devices 2 compat_flags 0x0 compat_ro_flags 0x0 incompat_flags 0x21 ( MIXED_BACKREF | BIG_METADATA ) csum_type 0 csum_size 4 cache_generation 9026 uuid_tree_generation 9026 dev_item.uuid 224c95e6-d71b-494a-a4f6-cc72a84f1e89 dev_item.fsid 09024c28-7932-4ddb-960d-becc1ea839e5 [match] dev_item.type 0 dev_item.total_bytes 4000787030016 dev_item.bytes_used 3527267057664 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 btrfs-show-super -a /dev/sde superblock: bytenr=65536, device=/dev/sde --------------------------------------------------------- csum 0x9634c164 [match] bytenr 65536 flags 0x1 ( WRITTEN ) magic _BHRfS_M [match] fsid 09024c28-7932-4ddb-960d-becc1ea839e5 label terrafirm generation 9026 root 1517167755264 sys_array_size 129 chunk_root_generation 8957 root_level 1 chunk_root 20971520 chunk_root_level 1 log_root 0 log_root_transid 0 log_root_level 0 total_bytes 8001574060032 bytes_used 7038625824768 sectorsize 4096 nodesize 16384 leafsize 16384 stripesize 4096 root_dir 6 num_devices 2 compat_flags 0x0 compat_ro_flags 0x0 incompat_flags 0x21 ( MIXED_BACKREF | BIG_METADATA ) csum_type 0 csum_size 4 cache_generation 9026 uuid_tree_generation 9026 dev_item.uuid d63b1c46-b5a2-49ae-861f-804b2f97f427 dev_item.fsid 09024c28-7932-4ddb-960d-becc1ea839e5 [match] dev_item.type 0 dev_item.total_bytes 4000787030016 dev_item.bytes_used 3527250280448 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 superblock: bytenr=67108864, device=/dev/sde --------------------------------------------------------- csum 0x3655e9aa [match] bytenr 67108864 flags 0x1 ( WRITTEN ) magic _BHRfS_M [match] fsid 09024c28-7932-4ddb-960d-becc1ea839e5 label terrafirm generation 9026 root 1517167755264 dev_item.type 0 dev_item.total_bytes 4000787030016 dev_item.bytes_used 3527250280448 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 superblock: bytenr=274877906944, device=/dev/sde --------------------------------------------------------- csum 0xcbd2bf9b [match] bytenr 274877906944 flags 0x1 ( WRITTEN ) magic _BHRfS_M [match] fsid 09024c28-7932-4ddb-960d-becc1ea839e5 label terrafirm generation 9026 root 1517167755264 sys_array_size 129 chunk_root_generation 8957 root_level 1 chunk_root 20971520 chunk_root_level 1 log_root 0 log_root_transid 0 log_root_level 0 total_bytes 8001574060032 bytes_used 7038625824768 sectorsize 4096 nodesize 16384 leafsize 16384 stripesize 4096 root_dir 6 num_devices 2 compat_flags 0x0 compat_ro_flags 0x0 incompat_flags 0x21 ( MIXED_BACKREF | BIG_METADATA ) csum_type 0 csum_size 4 cache_generation 9026 uuid_tree_generation 9026 dev_item.uuid d63b1c46-b5a2-49ae-861f-804b2f97f427 dev_item.fsid 09024c28-7932-4ddb-960d-becc1ea839e5 [match] dev_item.type 0 dev_item.total_bytes 4000787030016 dev_item.bytes_used 3527250280448 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 =============================== There's some difference between the output of /dev/sdc and /dev/sde but they may be completely normal. How does one determine from the above whether or not a superblock is bad? Is "btrfs rescue super-recover" safe to run? IOW, will it ask before doing anything possibly destructive (assuming I don't give it a -y)? Chris -- 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