OVERVIEW
========
Give insights of Linux LVM snapshots, and make incremental backups based on them.

Snapdiff is licensed under GPL v2, the same license of the Linux kernel.

USAGE
=====
Now, it is pretty early, can only dump information about a snapshot (the COW device).

make, and run dumpsnap:
	./dumpsnap <snapshot-cow-device>

FILES
=====
 * devcmp.py:   compare two devices, looking for different chunks.
                usually used to compare the snapshot and it's origin,
                to prove the correctness of dumpsnap.
 * dumpdev.py:  dump a chunk from a device, a debug tool.
 * dumpsnap.c:  compiles to dumpsnap, shows snapshot COW header and exception table.
                it uses O_DIRECT to read devices so it could reflect up-to-date info.
                it's recommended to sync the COW device after change.
 * dumpsnap.py: experimental code to verify the snapshot disk layout, works like
                dumpsnap but couldn't use O_DIRECT, so it won't see latest data.
 * rawread.c:   compiles to rawread, copy some data with O_DIRECT from beginning of
                the device to a file, so dumpsnap.py can work on latest data.