root@shark:~# btrfsck /dev/sdb
Checking filesystem on /dev/sdb
UUID: e032e16a-7624-464f-815f-f92d6bd14f03
checking extents
ref mismatch on [1173236776960 720896] extent item 0, found 1
Backref 1173236776960 root 1 owner 11776 offset 0 num_refs 0 not found in extent tree
Incorrect local backref count on 1173236776960 root 1 owner 11776 offset 0 found 1 wanted 0 back 0xe7cfd40
backpointer mismatch on [1173236776960 720896]
ref mismatch on [18765422821376 720896] extent item 1, found 0
Incorrect local backref count on 18765422821376 root 1 owner 11776 offset 0 found 0 wanted 1 back 0x80099a0
Backref disk bytenr does not match extent record, bytenr=18765422821376, ref bytenr=18765315510272
backpointer mismatch on [18765422821376 720896]
owner ref check failed [18765422821376 720896]
Errors found in extent allocation tree or chunk allocation
checking free space cache
Couldn't map the block 1173236776960
failed to load free space cache for block group 18436859166720
checking fs roots
root 18446744073709551607 inode 1529 errors 1000, some csum missing
found 854791626229 bytes used err is 1
total csum bytes: 2085289076
total tree bytes: 4004085760
total fs tree bytes: 1690386432
total extent tree bytes: 133726208
btree space waste bytes: 482943197
file data blocks allocated: 2135735193600
 referenced 2165157146624
Btrfs v3.17.2


root@shark:~# btrfs check /dev/sdb
Checking filesystem on /dev/sdb
UUID: e032e16a-7624-464f-815f-f92d6bd14f03
checking extents
ref mismatch on [1173236776960 720896] extent item 0, found 1
Backref 1173236776960 root 1 owner 11776 offset 0 num_refs 0 not found in extent tree
Incorrect local backref count on 1173236776960 root 1 owner 11776 offset 0 found 1 wanted 0 back 0xe160d40
backpointer mismatch on [1173236776960 720896]
ref mismatch on [18765422821376 720896] extent item 1, found 0
Incorrect local backref count on 18765422821376 root 1 owner 11776 offset 0 found 0 wanted 1 back 0x799a9a0
Backref disk bytenr does not match extent record, bytenr=18765422821376, ref bytenr=18765315510272
backpointer mismatch on [18765422821376 720896]
owner ref check failed [18765422821376 720896]
Errors found in extent allocation tree or chunk allocation
checking free space cache
Couldn't map the block 1173236776960
failed to load free space cache for block group 18436859166720
checking fs roots
root 18446744073709551607 inode 1529 errors 1000, some csum missing
found 854791626229 bytes used err is 1
total csum bytes: 2085289076
total tree bytes: 4004085760
total fs tree bytes: 1690386432
total extent tree bytes: 133726208
btree space waste bytes: 482943197
file data blocks allocated: 2135735193600
 referenced 2165157146624
Btrfs v3.17.2