Provided by: btrfs-tools_3.12-1ubuntu0.2_amd64 

NAME
btrfs-map-logical - map btrfs logical extent to physical extent
SYNOPSIS
btrfs-map-logical [options] <device>
DESCRIPTION
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.
Options
-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.
EXIT CODE
btrfs-map-logical will return 0 if no error happened. If any problems happened, 1 will be returned.
AUTHOR
Written by Shilong Wang and Wenruo Qu.
COPYRIGHT
Copyright © 2013 Fujitsu, Inc. License GPLv2: GNU GPL version 2 <http://gnu.org/licenses/gpl.html>.
This is free software: you are free to change and redistribute it. There is NO WARRANTY, to the
extent permitted by law.
SEE ALSO
mkfs.btrfs(8)
BTRFS-MAP-LOGICAL(8)