I have an external drive formatted with BTRFS that seems refuses to mount:$ sudo mount -vs -t btrfs  -o ro,recovery,errors=continue /dev/sdb2 /media/user/dirmount: /dev/sdb2: can't read superblockHowever, when BTRFS thinks that all the superblocks are okay:$ sudo btrfs rescue super-recover -v /dev/sdb2                 All Devices:        Device: id = 1, name = /dev/sdb2Before Recovering:        [All good supers]:                device name = /dev/sdb2                superblock bytenr = 65536                device name = /dev/sdb2                superblock bytenr = 67108864                device name = /dev/sdb2                superblock bytenr = 274877906944        [All bad supers]:All supers are valid, no need to recoverAnd if I try specifying sb=$((67108864/4)) (mount uses 1k units, so you have to divide by 4 on a system with 4k blocks) to use one of the alternative superblocks, I get the same error. btrfs restore also seems to have no trouble reading data from the drive, and btrfs check complains only about an invalid cache entry (and clear_cache doesn't help when mounting). This has happened once before on another drive and btrfs check --repair also didn't work.[1] As there is a large amount of data on this drive, I'm a bit reluctant to copy everything elsewhere with btrfs restore (which also means finding space elsewhere), reformat, and copy everything back. Is there a way to fix this issue? Is there a way to invoke btrfs directly so that it performs the mount instead of relying on mount? I couldn't find a mount.btrfs.[1] I'm a bit reluctant to use btrfs check --repair as it is comes with lots of warnings about being a measure of last resort, especially after it not working previously. 
Btrfs super-recover says all superblocks are good but mount disagrees
linux mint;btrfs;superblock