From c8c343a29241abba33ad0b0590305b30d3a54011 Mon Sep 17 00:00:00 2001
From: CyberLeo <cyberleo@cyberleo.net>
Date: Sun, 2 Jan 2011 14:35:02 -0600
Subject: [PATCH] update: add -n flag to avoid syncing and snapshotting an
 upstream tree that you know has not changed; useful for pushing overlay
 changes to the tree

---
 update | 41 ++++++++++++++++++++++++++++++-----------
 1 file changed, 30 insertions(+), 11 deletions(-)

diff --git a/update b/update
index 7d9d736..00bc7ae 100755
--- a/update
+++ b/update
@@ -4,12 +4,16 @@
 [ "$(id -u)" -eq 0 ] || exec sudo "${0}" "${@}"
 cd "$(dirname "${0}")"
 
+[ "${1}" = "-n" ] && NO_SYNC=true
+
 meh() { printf " \033[1;32m*\033[0m %s\n" "${*}"; }
 omg() { printf " \033[1;33m*\033[0m %s\n" "${*}"; }
 wtf() { printf " \033[1;31m*\033[0m %s\n" "${*}"; kill $$; exit 1; }
 
 sync="rsync://paka/freebsd-ports"
 
+sync_opts="--archive --compress --delete --hard-links --sparse --stats --verbose"
+
 ports=alba/ports
 upstream=alba/srcs/freebsd/ports/upstream
 prepare=alba/srcs/freebsd/ports/prepare
@@ -18,34 +22,47 @@ today="$(date +%Y-%m-%d)"
 ports_origin="$(zfs get -H -o value origin "${ports}")"
 ports_origin="${ports_origin%%@*}"
 ports_fs="$(zfs get -H -o value mountpoint "${ports}")"
+ports_fs="${ports_fs:-/usr/ports}"
 upstream_fs="$(zfs get -H -o value mountpoint "${upstream}")"
 
 # Make sure the ports tree is a descendent of the ports upstream
 [ "${ports_origin}" = "${upstream}" ] || wtf "Target ${ports} is not a child of ${upstream}
   (is ${ports_origin})"
 
-# Compute the next available snapshot
-last_snapshot="$(zfs list -rHt snapshot -o name "${upstream}" | grep "@${today}_" | sort | tail -n 1 | sed -e 's/^.*_\([0-9]\{2\}\)$/\1/')"
-if [ "${last_snapshot}" ]
+if [ -z "${NO_SYNC}" ]
 then
-  snapshot="$(printf "${today}_%02u" "$(( ${last_snapshot} + 1 ))")"
-  echo "${today}_${last_snapshot} -> ${snapshot}"
+  # Compute the next available snapshot
+  last_snapshot="$(zfs list -rHt snapshot -o name "${upstream}" | grep "@${today}_" | sort | tail -n 1 | sed -e 's/^.*_\([0-9]\{2\}\)$/\1/')"
+  if [ "${last_snapshot}" ]
+  then
+    snapshot="$(printf "${today}_%02u" "$(( ${last_snapshot} + 1 ))")"
+    echo "${today}_${last_snapshot} -> ${snapshot}"
+  else
+    snapshot="${today}_00"
+    echo "None -> ${snapshot}"
+  fi
 else
-  snapshot="${today}_00"
-  echo "None -> ${snapshot}"
+  # Don't bother creating a new snapshot if the tree will not be synchronized
+  last_snapshot="$(zfs list -rHt snapshot -o name "${upstream}" | sort | tail -n 1)"
+  snapshot="${last_snapshot##*@}"
+  echo "Using existing snapshot ${snapshot}"
 fi
 
 # Bail out if anything is /
 [ -z "${ports_fs}"  -o -z "${upstream_fs}" ] && wtf "Writing to /? Are you nuts?"
 
-meh "Update"
-rsync --archive --compress --delete --hard-links --sparse --stats --verbose "${sync}/" "${upstream_fs}/" || wtf "update failed"
+if [ -z "${NO_SYNC}" ]
+then
+  meh "Update"
+  rsync ${sync_opts} "${sync}/" "${upstream_fs}/" || wtf "update failed"
 
-meh "Snapshot"
-zfs snapshot "${upstream}@${snapshot}" || wtf "snapshot failed"
+  meh "Snapshot"
+  zfs snapshot "${upstream}@${snapshot}" || wtf "snapshot failed"
+fi
 
 meh "Clone"
 zfs clone "${upstream}@${snapshot}" "${prepare}" || wtf "clone failed"
+zfs set atime=off "${prepare}" || wtf "atime-off failed"
 
 # Resolve filesystem mountpoints, now that everything should exist
 prepare_fs="$(zfs get -H -o value mountpoint "${prepare}")"
@@ -61,6 +78,8 @@ do
 done
 
 meh "Install"
+zfs set readonly=on "${prepare}" || wtf "readonly failed"
+# Only move old ports tree out of the way if it exists
 zfs rename "${ports}" "${ports}-bak" || wtf "backup rename failed"
 zfs rename "${prepare}" "${ports}" || wtf "rename prepare -> ports failed"
 zfs inherit mountpoint "${ports}-bak" || wtf "inherit failed"
-- 
2.42.0