From b4136430d7408a0b26f8662c6387e78ac2c04cb6 Mon Sep 17 00:00:00 2001
From: Max Christian Pohle
Date: Mon, 29 Mar 2021 00:19:37 +0200
Subject: Added warning to zfs-squash-datasets script

---
 zfs-squash-datasets.sh | 115 +++++++++++++++++++++++++++++++++++++++----------
 1 file changed, 93 insertions(+), 22 deletions(-)

diff --git a/zfs-squash-datasets.sh b/zfs-squash-datasets.sh
index d668c80..3623edf 100755
--- a/zfs-squash-datasets.sh
+++ b/zfs-squash-datasets.sh
@@ -1,42 +1,99 @@
 #!/usr/local/bin/bash
-DATASET_ROOT=$1
-DATASET_TARGET=$2
 
-MOUNTPOINT_TARGET=$(zfs get -o value -H mountpoint $DATASET_TARGET)
+# DO NOT USE THIS SCRIPT
+# It is in a state of hot garbage and will probably be deleted soon
 
-if ! test -d "$MOUNTPOINT_TARGET"; then
+
+print_help_and_exit() {
     echo "Please run this program with a source and a target dataset name as arguments"
     echo "e.g. $0 zpool/dataset1 zpool/dataset2"
     exit
+}
+
+SIMULATION=0
+
+args=$(getopt n $*)
+test $? == 0 || print_help_and_exit
+
+set -- $args
+
+while :; do
+    sleep 1
+    echo $1
+    case "$1" in
+        --) shift; break ;;
+        -n) SIMULATION=1 ; shift ;;
+    esac
+done
+
+DATASET_ROOT=$1
+DATASET_TARGET=$2
+
+if ! zfs get mountpoint $DATASET_TARGET >/dev/null; then
+    echo "Dataset $DATASET_TARGET does not exist and will be created."
+    echo "You have 10 seconds to abort this with CTRL-C"
+    sleep 10
+    if ! $SIMULATION; then
+        zfs create $DATASET_TARGET
+    fi
 fi
 
+if zfs get -H -t filesystem -o name,value -r snapdir zeus/data/projects | grep -v visible >/dev/null; then
+    echo Please make all snapdirs visible:
+    zfs get -H -t filesystem -o name,value -r snapdir zeus/data/projects
+    exit 2
+fi
+
+
+MOUNTPOINT_TARGET=$(zfs get -o value -H mountpoint $DATASET_TARGET)
+test ${SIMULATION:0} = 1 && test $MOUNTPOINT_TARGET == "" && MOUNTPOINT_TARGET="datapool/simulation"
+
+test -d "$MOUNTPOINT_TARGET" || print_help_and_exit
+
 # make sure, that ctrl-c also works in the inner loops
 trap exit INT
 
 # recursively contains all snapshot names (the part after the @) from root on, sorted and only once
-SNAPSHOTS=$(zfs list -H  -oname -tsnap -r $DATASET_ROOT| cut -d@ -f2 | sort  | uniq)
+SNAPSHOTS=$(zfs list -H  -oname -tsnap -r $DATASET_ROOT | cut -d@ -f2 | sort -u)
 DATASETS=$(zfs list -H -oname -t filesystem -r $DATASET_ROOT)
 
+test "${SIMULATION:-0}" = 1 && echo "SIMULATION MODE"
+
+$DATASETS
+
+
 echo "We are going to flatten the hierachy of this dataset:"
-printf "    %s\n" $DATASETS
-echo "into the dataset with the name:"
-echo "    $DATASET_TARGET"
-echo "mounted under:"
-echo "    $MOUNTPOINT_TARGET"
+printf "\t%s\n" $DATASETS
+echo -e "into the dataset with the name:"
+echo -e "\t$DATASET_TARGET"
+echo -e "mounted under:"
+echo -e "\t$MOUNTPOINT_TARGET"
+echo -e "with the following snapshots:"
+printf "\t%s\n" $SNAPSHOTS
 echo ""
 echo "You have 10 seconds to abort this with CTRL-C"
 sleep 10
 
+set -- $SNAPSHOTS
+SNAPSHOTS_TOTAL=$#
+SNAPSHOT_CURRENT=0
+
+set -- $DATASETS
+shift
+SUBDATASETS=$@
+
 for SNAPSHOT in $SNAPSHOTS; do
     echo ""
     echo ""
-    echo "==========================="
-    echo "Next snapshot is: $SNAPSHOT"
-    echo "==========================="
+    SNAPSHOT_CURRENT=$((SNAPSHOT_CURRENT + 1))
+    echo "[$SNAPSHOT_CURRENT/$SNAPSHOTS_TOTAL] Next snapshot is: $SNAPSHOT"
+
+    for DATASET in $SUBDATASETS; do
 
-    for DATASET in $DATASETS; do
+        DATASET_RELATIVE=${DATASET##$DATASET_ROOT}
 
         MOUNTPOINT=$(zfs get -H -o value mountpoint $DATASET)
+        echo "RELATIVE=$DATASET_RELATIVE"
 
         if [[ $MOUNTPOINT == "legacy" ]]; then
             MOUNTPOINT=$(findmnt -n -o target $DATASET)
@@ -51,18 +108,32 @@ for SNAPSHOT in $SNAPSHOTS; do
             continue
         fi
 
-        SNAPDIR=$(realpath $MOUNTPOINT/.zfs/snapshot/$SNAPSHOT)
+        SNAPDIR=$MOUNTPOINT/.zfs/snapshot/$SNAPSHOT
         if test -d $SNAPDIR; then
-            TARGET_DIR="$(realpath $MOUNTPOINT_TARGET)$(realpath $MOUNTPOINT)"
-            mkdir -p "$TARGET_DIR"
-            echo rsync --info=stats3 -a "$SNAPDIR/" "$TARGET_DIR/"
-            if ! rsync --info=stats3 -a "$SNAPDIR/" "$TARGET_DIR/" ; then
-                >&2 echo "rsync could not entirely copy from $SNAPDIR to $DATASET_TARGET"
+
+            TARGET_DIR="${MOUNTPOINT_TARGET}${DATASET_RELATIVE}"
+
+            echo -e \\trsync --info=stats3 --delete -a "$SNAPDIR/" "$TARGET_DIR/"
+            if test "${SIMULATION:-0}" = 0; then
+
+                mkdir -p "$TARGET_DIR"
+
+                if ! rsync --info=stats3 --delete -a "$SNAPDIR/" "$TARGET_DIR/" ; then
+                    >&2 echo "rsync could not entirely copy from $SNAPDIR to $DATASET_TARGET"
+                fi
             fi
+        else
+            echo -e "\tSKIP: Snapshot $SNAPSHOT does not exist for dataset $DATASET"
         fi
     done
+
     NEW_SNAPSHOT="$DATASET_TARGET@$SNAPSHOT"
-    echo "Files copied, creating snapshot: $NEW_SNAPSHOT"
-    zfs snap $NEW_SNAPSHOT
+    echo ""
+    echo -e "\t> Concluding snapshot: ${NEW_SNAPSHOT} <"
+    echo ""
+
+    if test "${SIMULATION:-0}" = 0; then
+        zfs snap $NEW_SNAPSHOT
+    fi
 done
 
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