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 to stdout by 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.
mkfs.btrfs(8)