Provided by: btrfs-tools_4.4-1_amd64
btrfs-map-logical - map btrfs logical extent to physical extent
btrfs-map-logical <options> <device>
btrfs-map-logical can be used to find out what the physical offsets are on the mirrors, the result is dumped into stdout in default. Mainly used for debug purpose.
-l|--logical <logical_num> Logical extent to map. -c|--copy <copy> Copy of the extent to read(usually 1 or 2). -o|--output <filename> Output file to hold the extent. -b|--bytes <bytes> Number of bytes to read.
btrfs-map-logical will return 0 if no error happened. If any problems happened, 1 will be returned.