On Mon, Aug 3, 2015 at 1:17 AM, Duncan <1i5t5.duncan@xxxxxxx> 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
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