Systemd mount generator: Generate noauto units; add control properties

This commit refactors the systemd mount generators and makes the
following major changes:

- The generator now generates units for datasets marked canmount=noauto,
  too. These units are NOT WantedBy local-fs.target.
  If there are multiple noauto datasets for a path, no noauto unit will
  be created. Datasets with canmount=on are prioritized.

- Introduces handling of new user properties which are now included in
  the zfs-list.cache files:
    - org.openzfs.systemd:requires:
      List of units to require for this mount unit
    - org.openzfs.systemd:requires-mounts-for:
      List of mounts to require by this mount unit
    - org.openzfs.systemd:before:
      List of units to order after this mount unit
    - org.openzfs.systemd:after:
      List of units to order before this mount unit
    - org.openzfs.systemd:wanted-by:
      List of units to add a Wants dependency on this mount unit to
    - org.openzfs.systemd:required-by:
      List of units to add a Requires dependency on this mount unit to
    - org.openzfs.systemd:nofail:
      Toggles between a wants and a requires dependency.
    - org.openzfs.systemd:ignore:
      Do not generate a mount unit for this dataset.

  Consult the updated man page for detailed documentation.

- Restructures and extends the zfs-mount-generator(8) man page with the
  above properties, information on unit ordering and a license header.

Reviewed-by: Richard Laager <[email protected]>
Reviewed-by: Antonio Russo <[email protected]>
Reviewed-by: Brian Behlendorf <[email protected]>
Signed-off-by: InsanePrawn <[email protected]>
Closes #9649

1 files changed, 13 insertions, 4 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 6d0f44ab3..053b4414a 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
@@ -46,8 +46,13 @@ case "${ZEVENT_HISTORY_INTERNAL_NAME}" in
     set|inherit)
         # Only act if one of the tracked properties is altered.
         case "${ZEVENT_HISTORY_INTERNAL_STR%%=*}" in
-            canmount|mountpoint|atime|relatime|devices|exec| \
-                readonly|setuid|nbmand|encroot|keylocation) ;;
+            canmount|mountpoint|atime|relatime|devices|exec|readonly| \
+              setuid|nbmand|encroot|keylocation|org.openzfs.systemd:requires| \
+              org.openzfs.systemd:requires-mounts-for| \
+              org.openzfs.systemd:before|org.openzfs.systemd:after| \
+              org.openzfs.systemd:wanted-by|org.openzfs.systemd:required-by| \
+              org.openzfs.systemd:nofail|org.openzfs.systemd:ignore \
+            ) ;;
             *) exit 0 ;;
         esac
       ;;
@@ -61,8 +66,12 @@ esac
 zed_lock zfs-list
 trap abort_alter EXIT
 
-PROPS="name,mountpoint,canmount,atime,relatime,devices,exec,readonly"
-PROPS="${PROPS},setuid,nbmand,encroot,keylocation"
+PROPS="name,mountpoint,canmount,atime,relatime,devices,exec\
+,readonly,setuid,nbmand,encroot,keylocation\
+,org.openzfs.systemd:requires,org.openzfs.systemd:requires-mounts-for\
+,org.openzfs.systemd:before,org.openzfs.systemd:after\
+,org.openzfs.systemd:wanted-by,org.openzfs.systemd:required-by\
+,org.openzfs.systemd:nofail,org.openzfs.systemd:ignore"
 
 "${ZFS}" list -H -t filesystem -o $PROPS -r "${ZEVENT_POOL}" > "${FSLIST_TMP}"