e2mmpstatus is a Multi-Mount Protection (MMP) helper utility to read
an MMP block to see if it is being updated.  It can also output the
latest update time, nodename, and device from the MMP block.

This is useful for HA and other maintenance scripts to determine if
the filesystem is in use on another node, and which node it is.

Signed-off-by: Shuichi Ihara <sihara@ddn.com>
Signed-off-by: Li Xi <lixi@ddn.com>
Signed-off-by: Wang Shilong <wshilong@ddn.com>

Moved e2mmpstatus checking/dumping code to be part of dumpe2fs rather
than a standalone program, using the "-m" option to check MMP status,
and "-i" to dump info.  If dumpe2fs is called as "e2mmpstatus" (and
also "mmpstatus" for compatibility reasons), assume "-m" is specified.

Re-use the existing MMP block handing routines (with some changes) to
check and dump the MMP block, rather than adding duplicate versions.

Modify dumpe2fs to exit with a non-zero error code if there is an
error while reading the files...