Add canonical mount options zfs-mount-generator

lib/libzfs/libzfs_mount.c:zfs_add_options provides the canonical
mount options used by a `zfs mount` command. Because we cannot call
`zfs mount` directly from a systemd.mount unit, we mirror that logic
in zfs-mount-generator.

The zed script is updated to cache these properties as well.

Include a mini-tutorial in the manual page, properly substitute
configuration paths in zfs-mount-generator.8.in, and standardize the
Makefile.

Reviewed-by: Brian Behlendorf <[email protected]>
Reviewed-by: Richard Laager <[email protected]>
Signed-off-by: Antonio Russo <[email protected]>
Closes #7453 

4 files changed, 146 insertions, 38 deletions

diff --git a/cmd/zed/zed.d/history_event-zfs-list-cacher.sh.in b/cmd/zed/zed.d/history_event-zfs-list-cacher.sh.in
index 348c8d67a..c1513cf3a 100755
--- a/cmd/zed/zed.d/history_event-zfs-list-cacher.sh.in
+++ b/cmd/zed/zed.d/history_event-zfs-list-cacher.sh.in
@@ -44,9 +44,10 @@ case "${ZEVENT_HISTORY_INTERNAL_NAME}" in
       ;;
 
     set|inherit)
-        # Only act if the mountpoint or canmount setting is altered.
-        case "${ZEVENT_HISTORY_INTERNAL_STR}" in
-            canmount=*|mountpoint=*) ;;
+        # Only act if one of the tracked properties is altered.
+        case "${ZEVENT_HISTORY_INTERNAL_STR%%=*}" in
+            canmount|mountpoint|atime|relatime|devices|exec| \
+                readonly|setuid|nbmand) ;;
             *) exit 0 ;;
         esac
       ;;
@@ -60,8 +61,10 @@ esac
 zed_lock zfs-list
 trap abort_alter EXIT
 
-"${ZFS}" list -H -tfilesystem -oname,mountpoint,canmount -r "${ZEVENT_POOL}" \
-    >"${FSLIST_TMP}"
+PROPS="name,mountpoint,canmount,atime,relatime,devices,exec,readonly"
+PROPS="${PROPS},setuid,nbmand"
+
+"${ZFS}" list -H -t filesystem -o $PROPS -r "${ZEVENT_POOL}" > "${FSLIST_TMP}"
 
 # Sort the output so that it is stable
 sort "${FSLIST_TMP}" -o "${FSLIST_TMP}"
diff --git a/etc/systemd/system-generators/zfs-mount-generator.in b/etc/systemd/system-generators/zfs-mount-generator.in
index e39a03036..08d0e1a55 100755
--- a/etc/systemd/system-generators/zfs-mount-generator.in
+++ b/etc/systemd/system-generators/zfs-mount-generator.in
@@ -49,38 +49,123 @@ req_dir="${dest_norm}/local-fs.target.wants/"
 mkdir -p "${req_dir}"
 
 # All needed information about each ZFS is available from
-# zfs list -H -t filesystem -oname,mountpoint,canmount
+# zfs list -H -t filesystem -o <properties>
 # cached in $FSLIST, and each line is processed by the following function:
+# See the list below for the properties and their order
 
 process_line() {
 
+  # -o name
+  dataset="${1}"
+  p_mountpoint="${2}"
+  p_canmount="${3}"
+  p_atime="${4}"
+  p_relatime="${5}"
+  p_devices="${6}"
+  p_exec="${7}"
+  p_readonly="${8}"
+  p_setuid="${9}"
+  p_nbmand="${10}"
+
   # Check for canmount=off .
-  if [ "${3}" = "off" ] ; then
+  if [ "${p_canmount}" = "off" ] ; then
     return
-  elif [ "${3}" = "noauto" ] ; then
+  elif [ "${p_canmount}" = "noauto" ] ; then
     # Don't let a noauto marked mountpoint block an "auto" market mountpoint
     return
-  elif [ "${3}" = "on" ] ; then
+  elif [ "${p_canmount}" = "on" ] ; then
     : # This is OK
   else
     do_fail "invalid canmount"
   fi
 
   # Check for legacy and blank mountpoints.
-  if [ "${2}" = "legacy" ] ; then
+  if [ "${p_mountpoint}" = "legacy" ] ; then
     return
-  elif [ "${2}" = "none" ] ; then
+  elif [ "${p_mountpoint}" = "none" ] ; then
     return
-  elif [ "${2%"${2#?}"}" != "/" ] ; then
+  elif [ "${p_mountpoint%"${p_mountpoint#?}"}" != "/" ] ; then
     do_fail "invalid mountpoint $*"
   fi
 
   # Escape the mountpoint per systemd policy.
-  mountfile="$(systemd-escape "${2#?}").mount"
+  mountfile="$(systemd-escape "${p_mountpoint#?}").mount"
+
+  # Parse options
+  # see lib/libzfs/libzfs_mount.c:zfs_add_options
+  opts=""
+
+  # atime
+  if [ "${p_atime}" = on ] ; then
+    # relatime
+    if [ "${p_relatime}" = on ] ; then
+      opts="${opts},atime,relatime"
+    elif [ "${p_relatime}" = off ] ; then
+      opts="${opts},atime,strictatime"
+    else
+      printf 'zfs-mount-generator.sh: (%s) invalid relatime\n' \
+        "${dataset}" >/dev/kmsg
+    fi
+  elif [ "${p_atime}" = off ] ; then
+    opts="${opts},noatime"
+  else
+    printf 'zfs-mount-generator.sh: (%s) invalid atime\n' \
+      "${dataset}" >/dev/kmsg
+  fi
+
+  # devices
+  if [ "${p_devices}" = on ] ; then
+    opts="${opts},dev"
+  elif [ "${p_devices}" = off ] ; then
+    opts="${opts},nodev"
+  else
+    printf 'zfs-mount-generator.sh: (%s) invalid devices\n' \
+      "${dataset}" >/dev/kmsg
+  fi
+
+  # exec
+  if [ "${p_exec}" = on ] ; then
+    opts="${opts},exec"
+  elif [ "${p_exec}" = off ] ; then
+    opts="${opts},noexec"
+  else
+    printf 'zfs-mount-generator.sh: (%s) invalid exec\n' \
+      "${dataset}" >/dev/kmsg
+  fi
+
+  # readonly
+  if [ "${p_readonly}" = on ] ; then
+    opts="${opts},ro"
+  elif [ "${p_readonly}" = off ] ; then
+    opts="${opts},rw"
+  else
+    printf 'zfs-mount-generator.sh: (%s) invalid readonly\n' \
+      "${dataset}" >/dev/kmsg
+  fi
+
+  # setuid
+  if [ "${p_setuid}" = on ] ; then
+    opts="${opts},suid"
+  elif [ "${p_setuid}" = off ] ; then
+    opts="${opts},nosuid"
+  else
+    printf 'zfs-mount-generator.sh: (%s) invalid setuid\n' \
+      "${dataset}" >/dev/kmsg
+  fi
+
+  # nbmand
+  if [ "${p_nbmand}" = on ]  ; then
+    opts="${opts},mand"
+  elif [ "${p_nbmand}" = off ] ; then
+    opts="${opts},nomand"
+  else
+    printf 'zfs-mount-generator.sh: (%s) invalid nbmand\n' \
+      "${dataset}" >/dev/kmsg
+  fi
 
   # If the mountpoint has already been created, give it precedence.
   if [ -e "${dest_norm}/${mountfile}" ] ; then
-    printf 'zfs-mount-generator.sh: %s.mount already exists\n' "${2}" \
+    printf 'zfs-mount-generator.sh: %s already exists\n' "${mountfile}" \
       >/dev/kmsg
     return
   fi
@@ -97,14 +182,14 @@ After=zfs-import.target
 Wants=zfs-import.target
 
 [Mount]
-Where=${2}
-What=${1}
+Where=${p_mountpoint}
+What=${dataset}
 Type=zfs
-Options=zfsutil,auto
+Options=defaults${opts},zfsutil
 EOF
 
-  # Finally, create the appropriate dependencies based on the ZFS properties.
-  [ "$3" = "on" ] & ln -s "../${mountfile}" "${req_dir}"
+  # Finally, create the appropriate dependency
+  ln -s "../${mountfile}" "${req_dir}"
 }
 
 # Feed each line into process_line
diff --git a/man/man8/Makefile.am b/man/man8/Makefile.am
index b6408ddf2..153cd518f 100644
--- a/man/man8/Makefile.am
+++ b/man/man8/Makefile.am
@@ -4,7 +4,6 @@ dist_man_MANS = \
 	vdev_id.8 \
 	zdb.8 \
 	zfs.8 \
-	zfs-mount-generator.8 \
 	zfs-program.8 \
 	zgenhostid.8 \
 	zinject.8 \
@@ -12,24 +11,18 @@ dist_man_MANS = \
 	zstreamdump.8
 
 nodist_man_MANS = \
-	zed.8
+	zed.8 \
+	zfs-mount-generator.8
 
 EXTRA_DIST = \
-	zed.8.in
+	zed.8.in \
+	zfs-mount-generator.8.in
 
-zed.8: $(srcdir)/zed.8.in
-
-do_subst = $(SED) \
-	-e 's|@libexecdir[@]|$(libexecdir)|g' \
-	-e 's|@runstatedir[@]|$(runstatedir)|g' \
-	-e 's|@sysconfdir[@]|$(sysconfdir)|g'
-
-$(nodist_man_MANS): Makefile
-	$(RM) $@ [email protected]
-	srcdir=''; \
-	  test -f ./[email protected] || srcdir=$(srcdir)/; \
-	  $(do_subst) $${srcdir}[email protected] >[email protected]
-	mv [email protected] $@
+$(nodist_man_MANS): %: %.in
+	-$(SED) -e 's,@libexecdir\@,$(libexecdir),g' \
+		-e 's,@runstatedir\@,$(runstatedir),g' \
+		-e 's,@sysconfdir\@,$(sysconfdir),g' \
+		$< >'$@'
 
 install-data-local:
 	$(INSTALL) -d -m 0755 "$(DESTDIR)$(mandir)/man8"
diff --git a/man/man8/zfs-mount-generator.8 b/man/man8/zfs-mount-generator.8.in
index af471e7c9..319ac8e57 100644
--- a/man/man8/zfs-mount-generator.8
+++ b/man/man8/zfs-mount-generator.8.in
@@ -1,11 +1,11 @@
 .TH "ZFS\-MOUNT\-GENERATOR" "8" "ZFS" "zfs-mount-generator" "\""
 .SH "NAME"
-zfs\-mount\-generator \- generates systemd mount units for zfs
+zfs\-mount\-generator \- generates systemd mount units for ZFS
 .SH SYNOPSIS
 .B /lib/systemd/system-generators/zfs\-mount\-generator
 .sp
 .SH DESCRIPTION
-The zfs\-mount\-generator implements the \fBGenerators Specification\fP
+zfs\-mount\-generator implements the \fBGenerators Specification\fP
 of
 .BR systemd (1),
 and is called during early boot to generate
@@ -26,7 +26,7 @@ information on ZFS mountpoints must be stored separately. The output
 of the command
 .PP
 .RS 4
-zfs list -H -oname,mountpoint,canmount
+zfs list -H -o name,mountpoint,canmount,atime,relatime,devices,exec,readonly,setuid,nbmand
 .RE
 .PP
 for datasets that should be mounted by systemd, should be kept
@@ -45,6 +45,33 @@ history_event-zfs-list-cacher.sh .
 .RE
 .PP
 .sp
+.SH EXAMPLE
+To begin, enable tracking for the pool:
+.PP
+.RS 4
+touch
+.RI @sysconfdir@/zfs/zfs-list.cache/ POOLNAME
+.RE
+.PP
+Then, enable the tracking ZEDLET:
+.PP
+.RS 4
+ln -s "@libexecdir@/zfs/zed.d/history_event-zfs-list-cacher.sh" "@sysconfdir@/zfs/zed.d/"
+
+systemctl enable zed.service
+
+systemctl restart zed.service
+.RE
+.PP
+Force the running of the ZEDLET by setting canmount=on for at least one dataset in the pool:
+.PP
+.RS 4
+zfs set canmount=on
+.I DATASET
+.RE
+.PP
+This forces an update to the stale cache file.
+.sp
 .SH SEE ALSO
 .BR zfs (5)
 .BR zfs-events (5)