X-Git-Url: http://xvm.mit.edu/gitweb/invirt/scripts/pv-fixup.git/blobdiff_plain/9641cd4c25251ecbfd112fd6b453d12fda077406..077bcfb0bdc7958233abc666c0220b0981500c3b:/lvmanip

diff --git a/lvmanip b/lvmanip
index aad381f..4df4d80 100644
--- a/lvmanip
+++ b/lvmanip
@@ -4,23 +4,56 @@ exit 1
 DISK=/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]+)/)'
+}
+
+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";
+  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
-    echo "Extracting $lvname from offset $offset"
-    dd if=$DISK of=part-$lvname bs=1M skip=$(( $offset * 8192 + 384 )) bs=512 count=1;
+    pvname=$(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
 }
 
-lvinfo () {
-  perl -ne 'print if ( /^(\s*)'"$1"' \{/ ... /^$1\}/ )' $ARCHIVE
+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/$lv
 # Only works for single-segment LVs.
 ddlv () {
@@ -40,3 +73,23 @@ ddlv () {
       skip=$(( $offset * 64 + 3 )) bs=64K count=$(( $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 $length PEs"
+    echo dd if=$DISK of=/dev/xenvg/$lvname bs=64K \
+      skip=$(($offset*64 + 3)) count=$(($length*64)) seek=$(($seek*64))
+  fi
+}