Btrfs-map-logical (8) Linux Manual Page

btrfs-map-logical – map btrfs logical extent to physical extent

Synopsis

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.