lvm+dmsetup device mapper rules

[Michal Soltys <soltys@ziu.info>]

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This is an attempt at generic device mapper rules file. Both lvm and
manually (dmsetup) created devices are supported. The rules file depends
only on lvm and dmsetup binaries.

Standard /dev/disk/* symlinks are created at the end, with additional
/dev/disk/by-id/dm-uuid-* symlinks (by device's uuid, not filesystem's one).


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KERNEL=="device-mapper", NAME="mapper/control", GOTO="dm_end"

ACTION!="add|change", GOTO="dm_end"
SUBSYSTEM!="block", GOTO="dm_end"
KERNEL!="dm*", GOTO="dm_end"

# First get the name from dmsetup - it can be fed to lvs for parsing

PROGRAM="/sbin/dmsetup info -c --noheadings -o name -j%M -m%m", ENV{DM_NAME}="%c"
ENV{DM_NAME}!="?*", GOTO="dm_end"

ENV{DM_NAME}=="?*", NAME="mapper/$env{DM_NAME}"

# Try to get volume group name
# - lvs always indents first field with 2 spaces (thus %c{2})
# - note, that node doesn't have to exist, and it would fail if $tempnode was used

PROGRAM="/sbin/lvm lvs --ignorelockingfailure --noheadings -o vg_name /dev/mapper/$env{DM_NAME}", ENV{LVM_VGN}="%c{2}"
ENV{LVM_VGN}!="?*", GOTO="dm_finalize"
PROGRAM="/sbin/lvm lvs --ignorelockingfailure --noheadings -o lv_name /dev/mapper/$env{DM_NAME}", ENV{LVM_LVN}="%c{2}"
ENV{LVM_LVN}!="?*", GOTO="dm_finalize"

SYMLINK+="$env{LVM_VGN}/$env{LVM_LVN}"

LABEL="dm_finalize"

# /disk/* symlinks

PROGRAM="/sbin/dmsetup info -c --noheadings -o uuid -j%M -m%m", SYMLINK+="disk/by-id/dm-uuid-%c"
IMPORT{program}="vol_id --export $tempnode"
ENV{ID_FS_USAGE}=="filesystem|other|crypto", ENV{ID_FS_UUID_ENC}=="?*", SYMLINK+="disk/by-uuid/$env{ID_FS_UUID_ENC}"
ENV{ID_FS_USAGE}=="filesystem|other", ENV{ID_FS_LABEL_ENC}=="?*", SYMLINK+="disk/by-label/$env{ID_FS_LABEL_ENC}"

LABEL="dm_end"