libblkid: Optimize devicemapper support
This commit works by removing all calls from libdevmapper altogether,
and using the standard support for "normal" non-dm devices.
It depends on dm devices being placed in /dev/mapper (but the previous
code had this dependency anyway), and /proc/partitions containing dm
devices.
We don't actually rip out the libdevmapper code in this commit, but
just disable it via #undef HAVE_DEVMAPPER, just so it's easier to
review and understand the fundamental code changes. A subsequent
commit will remove the libdevmapper code, as well as unexport
the blkid_devdirs string array.
Thanks to Karel Zak for inspiring me to look at the dm code in blkid,
so I could realize how much it deserved to ripped out by its roots. :-)
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
4 files changed