.\" .\" Copyright 2018 Antonio Russo .\" Copyright 2019 Kjeld Schouten-Lebbing .\" Copyright 2020 InsanePrawn .\" .\" Permission is hereby granted, free of charge, to any person obtaining .\" a copy of this software and associated documentation files (the .\" "Software"), to deal in the Software without restriction, including .\" without limitation the rights to use, copy, modify, merge, publish, .\" distribute, sublicense, and/or sell copies of the Software, and to .\" permit persons to whom the Software is furnished to do so, subject to .\" the following conditions: .\" .\" The above copyright notice and this permission notice shall be .\" included in all copies or substantial portions of the Software. .\" .\" THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, .\" EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF .\" MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND .\" NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE .\" LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION .\" OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION .\" WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. .TH ZFS-MOUNT-GENERATOR 8 "Aug 24, 2020" OpenZFS .SH "NAME" zfs\-mount\-generator \- generates systemd mount units for ZFS .SH SYNOPSIS .B /lib/systemd/system-generators/zfs\-mount\-generator .sp .SH DESCRIPTION zfs\-mount\-generator implements the \fBGenerators Specification\fP of .BR systemd (1), and is called during early boot to generate .BR systemd.mount (5) units for automatically mounted datasets. Mount ordering and dependencies are created for all tracked pools (see below). .SS ENCRYPTION KEYS If the dataset is an encryption root, a service that loads the associated key (either from file or through a .BR systemd\-ask\-password (1) prompt) will be created. This service . BR RequiresMountsFor the path of the key (if file-based) and also copies the mount unit's .BR After , .BR Before and .BR Requires . All mount units of encrypted datasets add the key\-load service for their encryption root to their .BR Wants and .BR After . The service will not be .BR Want ed or .BR Require d by .BR local-fs.target directly, and so will only be started manually or as a dependency of a started mount unit. .SS UNIT ORDERING AND DEPENDENCIES mount unit's .BR Before \-> key\-load service (if any) \-> mount unit \-> mount unit's .BR After It is worth nothing that when a mount unit is activated, it activates all available mount units for parent paths to its mountpoint, i.e. activating the mount unit for /tmp/foo/1/2/3 automatically activates all available mount units for /tmp, /tmp/foo, /tmp/foo/1, and /tmp/foo/1/2. This is true for any combination of mount units from any sources, not just ZFS. .SS CACHE FILE Because ZFS pools may not be available very early in the boot process, information on ZFS mountpoints must be stored separately. The output of the command .PP .RS 4 zfs list -H -o 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 .RE .PP for datasets that should be mounted by systemd, should be kept separate from the pool, at .PP .RS 4 .RI /etc/zfs/zfs-list.cache/ POOLNAME . .RE .PP The cache file, if writeable, will be kept synchronized with the pool state by the ZEDLET .PP .RS 4 history_event-zfs-list-cacher.sh . .RE .PP .sp .SS PROPERTIES The behavior of the generator script can be influenced by the following dataset properties: .sp .TP 4 .BR canmount = on | off | noauto If a dataset has .BR mountpoint set and .BR canmount is not .BR off , a mount unit will be generated. Additionally, if .BR canmount is .BR on , .BR local-fs.target will gain a dependency on the mount unit. This behavior is equal to the .BR auto and .BR noauto legacy mount options, see .BR systemd.mount (5). Encryption roots always generate a key-load service, even for .BR canmount=off . .TP 4 .BR org.openzfs.systemd:requires\-mounts\-for = \fIpath\fR... Space\-separated list of mountpoints to require to be mounted for this mount unit .TP 4 .BR org.openzfs.systemd:before = \fIunit\fR... The mount unit and associated key\-load service will be ordered before this space\-separated list of units. .TP 4 .BR org.openzfs.systemd:after = \fIunit\fR... The mount unit and associated key\-load service will be ordered after this space\-separated list of units. .TP 4 .BR org.openzfs.systemd:wanted\-by = \fIunit\fR... Space-separated list of units that will gain a .BR Wants dependency on this mount unit. Setting this property implies .BR noauto . .TP 4 .BR org.openzfs.systemd:required\-by = \fIunit\fR... Space-separated list of units that will gain a .BR Requires dependency on this mount unit. Setting this property implies .BR noauto . .TP 4 .BR org.openzfs.systemd:nofail = unset | on | off Toggles between a .BR Wants and .BR Requires type of dependency between the mount unit and .BR local-fs.target , if .BR noauto isn't set or implied. .BR on : Mount will be .BR WantedBy local-fs.target .BR off : Mount will be .BR Before and .BR RequiredBy local-fs.target .BR unset : Mount will be .BR Before and .BR WantedBy local-fs.target .TP 4 .BR org.openzfs.systemd:ignore = on | off If set to .BR on , do not generate a mount unit for this dataset. .RE See also .BR systemd.mount (5) .PP .SH EXAMPLE To begin, enable tracking for the pool: .PP .RS 4 touch .RI /etc/zfs/zfs-list.cache/ POOLNAME .RE .PP Then, enable the tracking ZEDLET: .PP .RS 4 ln -s "/usr/lib/zfs-linux/zed.d/history_event-zfs-list-cacher.sh" "/etc/zfs/zed.d" systemctl enable zfs-zed.service systemctl restart zfs-zed.service .RE .PP Force the running of the ZEDLET by setting a monitored property, e.g. .BR canmount , 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. To test the generator output, run .PP .RS 4 /lib/systemd/system-generators/zfs-mount-generator /tmp/zfs-mount-generator . . .RE .PP This will generate units and dependencies in .I /tmp/zfs-mount-generator for you to inspect them. The second and third argument are ignored. If you're satisfied with the generated units, instruct systemd to re-run all generators: .PP .RS 4 systemctl daemon-reload .RE .PP .sp .SH SEE ALSO .BR zfs (5) .BR zfs-events (5) .BR zed (8) .BR zpool (5) .BR systemd (1) .BR systemd.target (5) .BR systemd.special (7) .BR systemd.mount (7)