systemd zfs-import.target and documentation

zfs-import-{cache,scan}.service must complete before any mounting of
filesystems can occur. To simplify this dependency, create a target
that is reached After (in the systemd sense) the pool is imported.

Additionally, recommend that legacy zfs mounts use the option

x-systemd.requires=zfs-import.target

to codify this requirement.

Reviewed-by: Fabian Grünbichler <f.gruenbichler@proxmox.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Giuseppe Di Natale <dinatale2@llnl.gov>
Signed-off-by: Antonio Russo <antonio.e.russo@gmail.com>
Closes #6764
This commit is contained in:
Antonio Russo 2017-10-30 16:18:26 -04:00 committed by Brian Behlendorf
parent ca85d69097
commit 5c2552c564
6 changed files with 23 additions and 7 deletions

View File

@ -7,6 +7,7 @@ systemdunit_DATA = \
zfs-import-scan.service \ zfs-import-scan.service \
zfs-mount.service \ zfs-mount.service \
zfs-share.service \ zfs-share.service \
zfs-import.target \
zfs.target zfs.target
EXTRA_DIST = \ EXTRA_DIST = \
@ -15,6 +16,7 @@ EXTRA_DIST = \
$(top_srcdir)/etc/systemd/system/zfs-import-scan.service.in \ $(top_srcdir)/etc/systemd/system/zfs-import-scan.service.in \
$(top_srcdir)/etc/systemd/system/zfs-mount.service.in \ $(top_srcdir)/etc/systemd/system/zfs-mount.service.in \
$(top_srcdir)/etc/systemd/system/zfs-share.service.in \ $(top_srcdir)/etc/systemd/system/zfs-share.service.in \
$(top_srcdir)/etc/systemd/system/zfs-import.target.in \
$(top_srcdir)/etc/systemd/system/zfs.target.in \ $(top_srcdir)/etc/systemd/system/zfs.target.in \
$(top_srcdir)/etc/systemd/system/50-zfs.preset.in $(top_srcdir)/etc/systemd/system/50-zfs.preset.in

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@ -7,6 +7,7 @@ After=systemd-udev-settle.service
After=cryptsetup.target After=cryptsetup.target
After=systemd-remount-fs.service After=systemd-remount-fs.service
Before=dracut-mount.service Before=dracut-mount.service
Before=zfs-import.target
ConditionPathExists=@sysconfdir@/zfs/zpool.cache ConditionPathExists=@sysconfdir@/zfs/zpool.cache
[Service] [Service]
@ -16,5 +17,4 @@ ExecStartPre=/sbin/modprobe zfs
ExecStart=@sbindir@/zpool import -c @sysconfdir@/zfs/zpool.cache -aN ExecStart=@sbindir@/zpool import -c @sysconfdir@/zfs/zpool.cache -aN
[Install] [Install]
WantedBy=zfs-mount.service WantedBy=zfs-import.target
WantedBy=zfs.target

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@ -6,6 +6,7 @@ Requires=systemd-udev-settle.service
After=systemd-udev-settle.service After=systemd-udev-settle.service
After=cryptsetup.target After=cryptsetup.target
Before=dracut-mount.service Before=dracut-mount.service
Before=zfs-import.target
ConditionPathExists=!@sysconfdir@/zfs/zpool.cache ConditionPathExists=!@sysconfdir@/zfs/zpool.cache
[Service] [Service]
@ -15,5 +16,4 @@ ExecStartPre=/sbin/modprobe zfs
ExecStart=@sbindir@/zpool import -aN -o cachefile=none ExecStart=@sbindir@/zpool import -aN -o cachefile=none
[Install] [Install]
WantedBy=zfs-mount.service WantedBy=zfs-import.target
WantedBy=zfs.target

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@ -0,0 +1,6 @@
[Unit]
Description=ZFS pool import target
[Install]
WantedBy=zfs-mount.service
WantedBy=zfs.target

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@ -3,8 +3,7 @@ Description=Mount ZFS filesystems
Documentation=man:zfs(8) Documentation=man:zfs(8)
DefaultDependencies=no DefaultDependencies=no
After=systemd-udev-settle.service After=systemd-udev-settle.service
After=zfs-import-cache.service After=zfs-import.target
After=zfs-import-scan.service
After=systemd-remount-fs.service After=systemd-remount-fs.service
Before=local-fs.target Before=local-fs.target

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@ -461,7 +461,16 @@ If needed, ZFS file systems can also be managed with traditional tools
If a file system's mount point is set to If a file system's mount point is set to
.Sy legacy , .Sy legacy ,
ZFS makes no attempt to manage the file system, and the administrator is ZFS makes no attempt to manage the file system, and the administrator is
responsible for mounting and unmounting the file system. responsible for mounting and unmounting the file system. Because pools must
be imported before a legacy mount can succeed, administrators should ensure
that legacy mounts are only attempted after the zpool import process
finishes at boot time. For example, on machines using systemd, the mount
option
.Pp
.Nm x-systemd.requires=zfs-import.target
.Pp
will ensure that the zfs-import completes before systemd attempts mounting
the filesystem. See systemd.mount(5) for details.
.Ss Deduplication .Ss Deduplication
Deduplication is the process for removing redundant data at the block level, Deduplication is the process for removing redundant data at the block level,
reducing the total amount of data stored. If a file system has the reducing the total amount of data stored. If a file system has the