Provided by: btrfs-tools_4.4-1_amd64
btrfs-show-super - show btrfs superblock information stored in devices
btrfs-show-super [options] <dev> [<dev>...]
btrfs-show-super is used to print the information of superblock, you can specify which mirror to print out. By default, every device’s first superblock will be printed out. Mainly used for debug purpose.
-f Print full superblock information. Including the system chunk array and backup roots. -a Print information of all superblocks. If this option is given, -i option will be ignored. -i <super_mirror> Specify which mirror to print out. <super_mirror> is between 0 and 2. If several -i <super_mirror> are given, only the last one is valid. -F Attempt to print the superblock even if no superblock magic is found. May end badly. -s <bytenr> specifiy offset to a superblock in a non-standard location at bytenr, useful for debugging (disables the -f option)
btrfs-show-super will return 0 if no error happened. If any problems happened, 1 will be returned.