initramfs: use mount.zfs instead of mount

A followup to d7a67402a8

For `mount -t zfs -o opts ds mp` command line
some implementations of `mount(8)`, e. g. Busybox in Debian
work as follows:

```
newfstatat(AT_FDCWD, "ds", 0x7fff826f4ab0, 0) = -1
mount("ds", "mp", "zfs", MS_SILENT, NULL) = 0
```

The logic above skips completely `mount.zfs` and prevents us
from reading filesystem properties and applying mount options.

For comparison, the coreutils `mount(8)` implementation does:

```
openat(AT_FDCWD, "/proc/filesystems", O_RDONLY|O_CLOEXEC) = 3
// figure out that zfs is a `nodev` filesystem and look for a helper
newfstatat(AT_FDCWD, "/sbin/mount.zfs" ...) = 0
execve("/sbin/mount.zfs" ...) = 0
```

Using `mount.zfs` in initramfs would help circumvent deficiencies
of some of `mount(8)` implementations. `mount -t zfs` translates
to `mount.zfs` invocation, except for cases when explicitly disabled
by `-i`.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: szubersk <szuberskidamian@gmail.com>
Closes #13305
This commit is contained in:
Damian Szuberski 2022-04-12 00:51:23 +02:00 committed by GitHub
parent ed715283de
commit 35d81a75a8
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@ -328,7 +328,7 @@ mount_fs()
# Need the _original_ datasets mountpoint!
mountpoint=$(get_fs_value "$fs" mountpoint)
ZFS_CMD="mount -o zfsutil -t zfs"
ZFS_CMD="mount.zfs -o zfsutil"
if [ "$mountpoint" = "legacy" ] || [ "$mountpoint" = "none" ]; then
# Can't use the mountpoint property. Might be one of our
# clones. Check the 'org.zol:mountpoint' property set in
@ -351,7 +351,7 @@ mount_fs()
# If it's not a legacy filesystem, it can only be a
# native one...
if [ "$mountpoint" = "legacy" ]; then
ZFS_CMD="mount -t zfs"
ZFS_CMD="mount.zfs"
fi
fi
@ -919,7 +919,7 @@ mountroot()
echo " not specified on the kernel command line."
echo ""
echo "Manually mount the root filesystem on $rootmnt and then exit."
echo "Hint: Try: mount -o zfsutil -t zfs ${ZFS_RPOOL-rpool}/ROOT/system $rootmnt"
echo "Hint: Try: mount.zfs -o zfsutil ${ZFS_RPOOL-rpool}/ROOT/system $rootmnt"
shell
fi