X-Git-Url: https://iankelling.org/git/?p=distro-setup;a=blobdiff_plain;f=mount-latest-subvol;h=aa35efa5720bbb9573b44939719a7baec8dd74a2;hp=359b534337669090503de236c2ab30467c35b4dd;hb=93db0c16393fe75efef3167c1d2b332f50387c23;hpb=f6347bfc9e2a597713b2f2758a2cc19214a1cc87

diff --git a/mount-latest-subvol b/mount-latest-subvol
index 359b534..aa35efa 100644
--- a/mount-latest-subvol
+++ b/mount-latest-subvol
@@ -13,13 +13,27 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-# usage: mount-latest-subvol
-#
-# Note, at source location, intentionally not executable, run and read
-# install-my-scripts.
-
+script=$(readlink -f -- "$BASH_SOURCE")
 cd /
-[[ $EUID == 0 ]] || exec sudo -E "$BASH_SOURCE" "$@"
+[[ $EUID == 0 ]] || exec sudo -E "$script" "$@"
+
+
+usage() {
+  cat <<EOF
+Usage: ${0##*/} [OPTIONS]
+
+-h|--help  Print help and exit.
+
+
+Note, at source location, intentionally not executable, run and read
+install-my-scripts.
+
+Note: Uses util-linux getopt option parsing: spaces between args and
+options, short options can be combined, options before args.
+EOF
+  exit $1
+}
+
 
 errcatch() {
   set -E; shopt -s extdebug
@@ -69,12 +83,22 @@ tu() {
     grep -xFq "$line" "$file" || tee -a "$file"<<<"$line"
   done
 }
-e() { printf "%s\n" "$*"; "$@"; }
+m() {
+  if $verbose; then
+    printf "%s\n" "$*"
+  fi
+  "$@"
+}
+x() {
+  printf "%s\n" "$*"
+  "$@"
+}
+
 mnt() {
   dir=$1
-  if ! mountpoint $dir &>/dev/null; then
+  if ! mountpoint -q $dir; then
     mkdir -p $dir
-    e mount $dir
+    m mount $dir
   fi
 }
 fstab() {
@@ -121,10 +145,26 @@ kill-dir() {
   return 1
 }
 
+##### begin command line parsing ########
+
+# you can remove this if you do not have options which can have args with spaces or empty.
+
+verbose=false
 force=false
-if [[ $1 == -f ]]; then
-  force=true
-fi
+temp=$(getopt -l help,force,verbose hfv "$@") || usage 1
+eval set -- "$temp"
+while true; do
+  case $1 in
+    -f|--force) force=true ;;
+    -v|--verbose) verbose=true ;;
+    -h|--help) usage ;;
+    --) shift; break ;;
+    *) echo "$0: unexpected args: $*" >&2 ; usage 1 ;;
+  esac
+  shift
+done
+
+##### end command line parsing ########
 
 ret=0
 
@@ -132,7 +172,7 @@ ret=0
 root_dev=$(awk '$2 == "/" {print $1}' /etc/mtab)
 if [[ $root_dev == /dev/dm-* ]]; then
   for d in /dev/mapper/*; do
-    if [[ $(readlink -f $d) == $root_dev ]]; then
+    if [[ $(readlink -f $d) == "$root_dev" ]]; then
       root_dev=$d
       break
     fi
@@ -163,7 +203,7 @@ shopt -s nullglob
 # ownership, and ssh doesn\'t allow any group writable parent
 # directories, so we are forced to use a directory structure similar
 # to home directories
-f=(/mnt/root/btrbk/q.*)
+f=(/mnt/root/btrbk/q.*); f=${f[0]}
 if [[ -e $f ]]; then
   fstab <<EOF
 $crypt_dev  /q  btrfs  noatime,subvol=q,gid=1000$noauto  0 0
@@ -171,7 +211,7 @@ $crypt_dev  /q  btrfs  noatime,subvol=q,gid=1000$noauto  0 0
 EOF
 fi
 
-f=(/mnt/root/btrbk/o.*)
+f=(/mnt/root/btrbk/o.*); f=${f[0]}
 if [[ -e $f ]]; then
   fstab <<EOF
 $crypt_dev  /o  btrfs  noatime,subvol=o$noauto  0 0
@@ -226,7 +266,7 @@ for vol in q a o i; do
 
 
   # if latest is already mounted, make sure binds are mounted and move on
-  e check-subvol-stale $d
+  m check-subvol-stale $d
   # populated by check-subvol-stale if stale
   if ! fresh_snap=$(cat /nocow/btrfs-stale/$vol 2>/dev/null); then
     mnt $d
@@ -239,15 +279,15 @@ for vol in q a o i; do
   umount_ret=true
   unmounted=()
   for dir in $(echo $d ${binds[*]}\ |tac -s\ ); do
-    if mountpoint $dir; then
-      if e umount -R $dir; then
+    if mountpoint -q $dir; then
+      if m umount -R $dir; then
         unmounted+=($dir)
       else
         if ! kill-dir TERM TERM TERM INT INT HUP HUP; then
           if $force; then  kill-dir KILL; fi
         fi
 
-        if e umount -R $dir; then
+        if m umount -R $dir; then
           unmounted+=($dir)
         else
           echo "$0: failed to umount $dir"
@@ -269,21 +309,59 @@ for vol in q a o i; do
   # todo: decipher /mnt/root, like we do in check-subvol-stale
   cd /mnt/root
   if [[ -e $vol ]]; then
-    e mv $vol $vol.leaf.$(date +%Y-%m-%dT%H:%M:%S%z)
+    leaf=$vol.leaf.$(date +%Y-%m-%dT%H:%M:%S%z)
+    m mv $vol $leaf
+    m btrfs property set -ts $leaf ro true
+
+    ### begin check if leaf is different, delete it if not ###
+    if [[ -e /a/opt/btrfs-snapshots-diff/btrfs-snapshots-diff.py ]]; then
+      parentid=$(btrfs sub show $leaf | awk '$1 == "Parent" && $2 == "UUID:" {print $3}')
+      bsubs=(/mnt/root/btrbk/$vol.*)
+      bsub=
+      # go in reverse order as its more likely to be at the end
+      for ((i=${#bsubs[@]}-1; i>=0; i--)); do
+        if [[ $parentid == $(btrfs sub show ${bsubs[i]} | awk '$1 == "UUID:" {print $2}') ]]; then
+          bsub=${bsubs[i]}
+          break
+        fi
+      done
+      if [[ $bsub ]]; then
+        tmp=$(mktemp)
+        # in testing, same subvol is 136 bytes. allow some overhead
+        btrfs send --no-data -p $bsub $leaf | head -c 1000 > $tmp
+        if (( $(stat -c%s $tmp) < 1000)); then
+          # example output for an empty diff:
+          # Found a valid Btrfs stream header, version 1
+          # o.leaf.2019-05-15T14:00:50-0400;snapshot: uuid=ba045ea30737dd449003f1ee40ec12d0, ctrasid=109533, clone_uuid=3c7e3544e486834aa71d89e5b8f30056, clone_ctransid=109533
+          lines=$(/a/opt/btrfs-snapshots-diff/btrfs-snapshots-diff.py -s -f $tmp | \
+                    grep -vxF "Found a valid Btrfs stream header, version 1" | \
+                    grep -cv "^[^;]*;snapshot: ") ||:
+          if [[ $lines == 0 ]]; then
+            x btrfs sub del $leaf
+          fi
+        fi
+      fi
+    fi
+    ### end check if leaf is different, delete it if not ###
+
+    ## begin expire leaf vols ##
     leaf_vols=($vol.leaf.*)
+    count=1
     for leaf in ${leaf_vols[@]}; do
       leaf_secs=$(date -d ${leaf#$vol.leaf.} +%s)
-      if (( $(date +%s) - 60*60*24*60 > leaf_secs )); then # 60 days
-        e btrfs sub del $leaf
+      if (( $(date +%s) - 60*60*24*60 > leaf_secs || count > 200 )); then # 60 days
+        x btrfs sub del $leaf
       fi
+      count=$((count+1))
     done
+    ## end expire leaf vols ##
   fi
   # Note, we make a few assumptions in this script, like
   # $d was not a different subvol id than $vol, and
   # things otherwise didn't get mounted very strangely.
-  e btrfs sub snapshot $fresh_snap $vol
+  m btrfs sub snapshot $fresh_snap $vol
   for dir in $d ${binds[@]}; do
-    e mnt $dir
+    m mnt $dir
   done
   stale_dir=/nocow/btrfs-stale
   rm -f $stale_dir/$d