\fBbtrfs-show-super\fP is used to print the information of superblock,
you can specify which mirror to print out. In default, every device's
first superblock will be printed out.
\fIOptions\fP
.IP"\fB-a\fP"5
print all the superblock information, if this option is given, '\fB-i\fP' option will be ignored.
.IP"\fB-i \fI<super_mirror>\fP"5
specify which mirror to print out. \fI<super_mirror>\fP is between 0 and 2. if several '\fB-i \fI<super_mirror>\fP'\fR are given, only the last one is valid.
.SHEXITCODE
\fBbtrfs-show-super\fR will return 0 exit code if no error happened.