Add scripts for making snapshots of LVs with dm-snapshot even when those LVs reside...

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

diff --git a/lvmanip b/lvmanip
index 44b61ca..2b9febb 100644 (file)
--- a/lvmanip
+++ b/lvmanip
@@ -1,25 +1,106 @@
+#!/bin/bash
+exit 1
+
+SOURCE=/dev/mapper/36090a028407d6e2b2589a45cdb971489
+
 # The name of the LVM archive to get data from
-ARCHIVE=/etc/lvm/archive/xenvg_00685.vg
+ARCHIVE=/etc/lvm/archive/xenvg_01514.vg
+
+lvmextractsection () {
+  perl -ne 'print if ( /^(\s*)'"$1"' [\{[]/ ... /^$1[\}\]]/ )'
+}
+lvmextractint () {
+  perl -lne 'print $1 if (/'"$1"' = ([0-9]+)/)'
+}
+
+# Extract the first block of an lv to a file named part-$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 $offset"
+    dd if=$SOURCE of=part-$lvname bs=1M skip=$(( $offset * 8192 + 384 )) bs=512 count=1;
+  fi
+}
+
+lvinfo () {
+  perl -ne 'print if ( /^(\s*)'"$1"' \{/ ... /^$1\}/ )' $ARCHIVE
+}
+segment2 () {
+  perl -ne 'print if ( /^(\s*)segment2 \{/ ... /^$1\}/ )'
+}
 
 # 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;
+  lvname="$1"
+  lvinfo=$(lvinfo "$lvname")
+  firststripe=$(echo "$lvinfo" | lvmextractsection 'stripes =' | tail -n +2 | head -n 1)
+  offset=$(echo "$firststripe" | cut -f 2 -d ,);
+  if [ -z "$offset" ]; then echo "WARNING: LV $lvname not found";
+  else
+    pvname=$(echo "$firststripe" | perl -pe 's/.*"([^"]+)".*/\1/')
+    pvdevice=$(cat $ARCHIVE | lvmextractsection "$pvname" | perl -lne 'print $1 if (/device = "(.+)"/)')
+    pe_start=$(cat $ARCHIVE | lvmextractsection "$pvname" | lvmextractint "pe_start")
+    echo "Extracting $lvname from PE offset $offset on $pvname ($pvdevice)"
+    dd if=$pvdevice of=part-$lvname bs=1M skip=$(( $offset * 8192 + $pe_start )) bs=512 count=1;
+  fi
+}
+
+if /bin/false; then
+# Usage:
+mkdir new
+mkdir old
+(cd old; for i in $(listlvs); do getfirstblock "$i"; done)
+(cd new; for i in $(listlvs); do dd if=/dev/xenvg/$i of=part-$i bs=512 count=1; done)
+
+diff -u <(cd old && sfdisk -l * 2>/dev/null) <(cd new && sfdisk -l * 2>/dev/null)
+(cd old && md5sum *) | (cd new && md5sum -c) | grep -v OK
+# end usage
 fi
+
+# Get a list of LVs in an LVM archive
+listlvs () {
+  cat $ARCHIVE | lvmextractsection "logical_volumes" | tail -n +2 | perl -lne 'if (/^(\s+)\S+\s+{/) { $indent ||= $1; }; print "$1" if /^$indent(\S+)\s+{/;'
 }
 
-# Generate a dd command to copy the lv data to /dev/xenvg/$lv
+
+# Generate a dd command to copy the LV data to /dev/xenvg/$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 $length PEs"
+    echo dd if=$SOURCE of=/dev/xenvg/$lvname \
+      skip=$(( $offset * 64 + 3 )) bs=64K count=$(( $length * 64 ))
+  fi
+}
+
+# Generate a dd command to copy the LV data for the second segment.
+ddlv2 () {
+  lvname="$1"
+  if ! lvinfo $lvname | grep -q 'segment_count = 2'; then
+    echo "# WARNING: LV $lvname has other than two segments, skipping" >&2
+    return 1
+  fi
+  offset=$(lvinfo $lvname | segment2 | perl -lne 'print $1 if (/"pv0", ([0-9]+)/)')
+  length=$(lvinfo $lvname | segment2 | perl -lne 'print $1 if (/extent_count = ([0-9]+)/)')
+  seek=$(lvinfo $lvname | segment2 | perl -lne 'print $1 if (/start_extent = ([0-9]+)/)')
+
+  if [ -z "$offset" ]; then
+    echo "# WARNING: LV $lvname not found";
+  else
+    echo "# Extracting $lvname segment 2 from offset $offset PEs with length $length PEs"
+    echo dd if=$SOURCE of=/dev/xenvg/$lvname bs=64K \
+      skip=$(($offset*64 + 3)) count=$(($length*64)) seek=$(($seek*64))
+  fi
 }