2020-05-30 04:16:08 +00:00
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[Unit]
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Description=Snapshot bootfs just before it is mounted
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Requisite=zfs-import.target
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2022-04-04 22:19:38 +00:00
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After=zfs-import.target dracut-pre-mount.service
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2020-05-30 04:16:08 +00:00
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Before=dracut-mount.service
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DefaultDependencies=no
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ConditionKernelCommandLine=bootfs.snapshot
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contrib: dracut: fix race with root=zfs:dset when necessities required
This had always worked in my testing, but a user on hardware reported
this to happen 100%, and I reproduced it once with cold VM host caches.
dracut-zfs-generator runs as a systemd generator, i.e. at Some
Relatively Early Time; if root= is a fixed dataset, it tries to
"solve [necessities] statically at generation time".
If by that point zfs-import.target hasn't popped (because the import is
taking a non-negligible amount of time for whatever reason), it'll see
no children for the root datase, and as such generate no mounts.
This has never had any right to work. No-one caught this earlier because
it's just that much more convenient to have root=zfs:AUTO, which orders
itself properly.
To fix this, always run zfs-nonroot-necessities.service;
this additionally simplifies the implementation by:
* making BOOTFS from zfs-env-bootfs.service be the real, canonical,
root dataset name, not just "whatever the first bootfs is",
and only set it if we're ZFS-booting
* zfs-{rollback,snapshot}-bootfs.service can use this instead of
re-implementing it
* having zfs-env-bootfs.service also set BOOTFSFLAGS
* this means the sysroot.mount drop-in can be fixed text
* zfs-nonroot-necessities.service can also be constant and always
enabled, because it's conditioned on BOOTFS being set
There is no longer any code generated at run-time
(the sysroot.mount drop-in is an unavoidable gratuitous cp).
The flow of BOOTFS{,FLAGS} from zfs-env-bootfs.service to sysroot.mount
is not noted explicitly in dracut.zfs(7), because (a) at some point it's
just visual noise and (b) it's already ordered via d-p-m.s from z-i.t.
Backport-of: 3399a30ee02d0d31ba2d43d0ce0a2fd90d5c575d
Signed-off-by: Ahelenia Ziemiańska <nabijaczleweli@nabijaczleweli.xyz>
2023-03-28 20:49:50 +00:00
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ConditionEnvironment=BOOTFS
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2020-05-30 04:16:08 +00:00
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[Service]
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Type=oneshot
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contrib: dracut: fix race with root=zfs:dset when necessities required
This had always worked in my testing, but a user on hardware reported
this to happen 100%, and I reproduced it once with cold VM host caches.
dracut-zfs-generator runs as a systemd generator, i.e. at Some
Relatively Early Time; if root= is a fixed dataset, it tries to
"solve [necessities] statically at generation time".
If by that point zfs-import.target hasn't popped (because the import is
taking a non-negligible amount of time for whatever reason), it'll see
no children for the root datase, and as such generate no mounts.
This has never had any right to work. No-one caught this earlier because
it's just that much more convenient to have root=zfs:AUTO, which orders
itself properly.
To fix this, always run zfs-nonroot-necessities.service;
this additionally simplifies the implementation by:
* making BOOTFS from zfs-env-bootfs.service be the real, canonical,
root dataset name, not just "whatever the first bootfs is",
and only set it if we're ZFS-booting
* zfs-{rollback,snapshot}-bootfs.service can use this instead of
re-implementing it
* having zfs-env-bootfs.service also set BOOTFSFLAGS
* this means the sysroot.mount drop-in can be fixed text
* zfs-nonroot-necessities.service can also be constant and always
enabled, because it's conditioned on BOOTFS being set
There is no longer any code generated at run-time
(the sysroot.mount drop-in is an unavoidable gratuitous cp).
The flow of BOOTFS{,FLAGS} from zfs-env-bootfs.service to sysroot.mount
is not noted explicitly in dracut.zfs(7), because (a) at some point it's
just visual noise and (b) it's already ordered via d-p-m.s from z-i.t.
Backport-of: 3399a30ee02d0d31ba2d43d0ce0a2fd90d5c575d
Signed-off-by: Ahelenia Ziemiańska <nabijaczleweli@nabijaczleweli.xyz>
2023-03-28 20:49:50 +00:00
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ExecStart=-/bin/sh -c '. /lib/dracut-lib.sh; SNAPNAME="$(getarg bootfs.snapshot)"; exec @sbindir@/zfs snapshot "$BOOTFS@${SNAPNAME:-%v}"'
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2020-05-30 04:16:08 +00:00
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RemainAfterExit=yes
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