lvmanip tweaks

[invirt/scripts/pv-fixup.git] / lvmanip

diff --git a/lvmanip b/lvmanip
index 44b61ca..aad381f 100644 (file)
--- a/lvmanip
+++ b/lvmanip
@@ -1,25 +1,42 @@
+#!/bin/bash
+exit 1
+
+DISK=/dev/mapper/36090a028407d6e2b2589a45cdb971489
+
 # The name of the LVM archive to get data from
 ARCHIVE=/etc/lvm/archive/xenvg_00685.vg
 
 # Extract the first block of an lv to a file named part-$lv
 getfirstblock () {
-lvname="$1"
-offset=$(grep -A16 $'\t'$lvname $ARCHIVE  | grep pv0 | cut -f 2 -d ,);
-if [ -z "$offset" ]; then echo "WARNING: LV not found";
-else
-echo "Extracting $lvname from offset $offset"
-dd if=/dev/mapper/36090a028407d6e2b2589a45cdb971489 of=part-$lvname bs=1M skip=$(( $offset * 8192 + 384 )) bs=512 count=1;
-fi
+  lvname="$1"
+  offset=$(grep -A16 $'\t'$lvname $ARCHIVE  | grep pv0 | cut -f 2 -d ,);
+  if [ -z "$offset" ]; then echo "WARNING: LV not found";
+  else
+    echo "Extracting $lvname from offset $offset"
+    dd if=$DISK of=part-$lvname bs=1M skip=$(( $offset * 8192 + 384 )) bs=512 count=1;
+  fi
 }
 
-# Generate a dd command to copy the lv data to /dev/xenvg/$lv
+lvinfo () {
+  perl -ne 'print if ( /^(\s*)'"$1"' \{/ ... /^$1\}/ )' $ARCHIVE
+}
+
+# Generate a dd command to copy the LV data to /dev/xenvg/$lv
+# Only works for single-segment LVs.
 ddlv () {
-lvname="$1"
-offset=$(grep -A16 $'\t'$lvname $ARCHIVE  | grep pv0 | cut -f 2 -d ,);
-length=$(( $(grep -A16 $'\t'$lvname $ARCHIVE  | grep extent_count | cut -f 2 -d = | cut -f 1 -d '#') ));
-if [ -z "$offset" ]; then echo "# WARNING: LV $lvname not found";
-else
-echo "#Extracting $lvname from offset $offset with length $length"
-echo dd if=/dev/mapper/36090a028407d6e2b2589a45cdb971489 of=/dev/xenvg/$lvname bs=1M skip=$(( $offset * 8192 + 384 )) ibs=512 obs=4194304 count=$length
-fi
+  lvname="$1"
+  if ! lvinfo $lvname | grep -q 'segment_count = 1'; then
+    echo "# WARNING: LV $lvname has more than one segment, skipping" >&2
+    return 1
+  fi
+  offset=$(lvinfo $lvname | perl -lne 'print $1 if (/"pv0", ([0-9]+)/)')
+  length=$(lvinfo $lvname | perl -lne 'print $1 if (/extent_count = ([0-9]+)/)')
+
+  if [ -z "$offset" ]; then
+    echo "# WARNING: LV $lvname not found";
+  else
+    echo "# Extracting $lvname from offset $offset PEs with length $length PEs"
+    echo dd if=$DISK of=/dev/xenvg/$lvname \
+      skip=$(( $offset * 64 + 3 )) bs=64K count=$(( $length * 64 ))
+  fi
 }