From: Lennart Poettering Date: Thu, 20 Mar 2025 21:51:04 +0000 (+0100) Subject: man: document new gpt-auto-generator features X-Git-Tag: v258-rc1~923^2~1 X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=c481605d0d9ef119eb392074aa58fd8af040ad25;p=thirdparty%2Fsystemd.git man: document new gpt-auto-generator features --- diff --git a/man/systemd-fstab-generator.xml b/man/systemd-fstab-generator.xml index f04334b9851..608a661a839 100644 --- a/man/systemd-fstab-generator.xml +++ b/man/systemd-fstab-generator.xml @@ -83,10 +83,14 @@ Configures the operating system's root filesystem to mount when running in the initrd. This accepts a device node path (usually /dev/disk/by-uuid/… or - /dev/disk/by-label/… or similar), or the special values gpt-auto, - fstab, and tmpfs. - - Use gpt-auto to explicitly request automatic root file system discovery via + /dev/disk/by-label/… or similar), or the special values + gpt-auto, gpt-auto-force, dissect, + dissect-force, fstab, fstab, and + off. + + Set to gpt-auto, gpt-auto-force, + dissect, dissect-force to explicitly request automatic root + file system discovery, implemented in systemd-gpt-auto-generator8. Use fstab to explicitly request automatic root file system discovery via @@ -103,6 +107,11 @@ filesystems (added in v258). Expects an absolute path name referencing an existing directory within the initrd's file hierarchy to boot into. + Set to off to turn off mounting of a root file system. + + Note that further root= values may be supported, implemented in additional + packages. + @@ -133,20 +142,18 @@ mount.usr= - Takes the /usr/ filesystem - to be mounted by the initrd. If - mount.usrfstype= or - mount.usrflags= is set, then - mount.usr= will default to the value set in + Takes the /usr/ filesystem to be mounted by the initrd. If + mount.usrfstype= or mount.usrflags= is set, then the mount + configured via mount.usr= will default to the the same value set in root=. - Otherwise, this parameter defaults to the - /usr/ entry found in - /etc/fstab on the root filesystem. + Set to dissect to explicitly request automatic /usr/ + file system discovery, implemented in + systemd-gpt-auto-generator8. - mount.usr= is honored by the initrd. - + Set to off to turn off mounting of a separate /usr/ file system. + mount.usr= is honored by the initrd. diff --git a/man/systemd-gpt-auto-generator.xml b/man/systemd-gpt-auto-generator.xml index 11b08f0b8de..c95221a4487 100644 --- a/man/systemd-gpt-auto-generator.xml +++ b/man/systemd-gpt-auto-generator.xml @@ -70,11 +70,11 @@ systemd-import-generator8 make sure to set the blockdev option and set the local name string to rootdisk to achieve this effect. Note that discovery of the root file system on - loopback block devices like this is only done if root=gpt-auto is specified - explicitly on the kernel command line, unlike the discovery based on the boot loader reported ESP which - is also enabled if no root= parameter is specified at all. (The latter relies on - systemd-udevd.service's /dev/gpt-auto-root block device symlink - generation). + loopback block devices like this is only done if root=gpt-auto or + root=dissect is specified explicitly on the kernel command line, unlike the + discovery based on the boot loader reported ESP which is also enabled if no root= + parameter is specified at all. (The latter relies on systemd-udevd.service's + /dev/gpt-auto-root block device symlink generation). @@ -317,6 +317,12 @@ and allows enforcing a policy on dissection and use of the automatically discovered GPT partition table entries. + Note that the specified image policy is not taken into account for automatic root or + /usr/ file system discovery unless + root=dissect/mount.usr=dissect (or + root=dissect-force) are specified. (The policy will always be applied to the other + auto-discoverable partition types.) + @@ -328,6 +334,12 @@ and allows enforcing a set of globbing patterns on the partition matching of the automatically discovered GPT partition table entries. + Note that the specified image filter is not taken into account for automatic root or + /usr/ file system discovery unless + root=dissect/mount.usr=dissect (or + root=dissect-force) are specified. (The filter will always be applied to the other + auto-discoverable partition types.) + @@ -337,17 +349,32 @@ rootflags= When root= is used with the special value - gpt-auto, full automatic discovery of the root partition based on the GPT + gpt-auto, basic automatic discovery of the root partition based on the GPT partition type is enabled. Use of the root partition is delayed until factory reset mode is left, in case it is enabled during the current boot. See Factory Reset for more information on that. If gpt-auto-force is specified - automatic discovery of the root partition is enabled, ignoring any factory reset mode. Any other - value disables this logic. + automatic discovery of the root partition is enabled, ignoring any factory reset mode. + + If root= is set to the special value dissect full + automatic discovery of the root partition based on GPT partition information is enabled. This is a + superset of root=gpt-auto, as it automatically configures Verity partitions + (including signature-based setup) following the logic defined for that in the Discoverable + Partitions Specification. Moreover it takes the configured image policy and image filter into + account for all partition types, including the root file system. root=dissect will + wait for the factory reset phase to be completed if it is in effect before activating the root file + system. Use root=dissect-force to ignore the factory reset phase and activate the + root file system immediately. + + Any other value (i.e. besides gpt-auto, gpt-auto-force, + dissect, dissect-force) disables automatic root file system + discovery. If root= is not specified at all on the kernel command line automatic discovery of the root partition via the ESP reported by the boot loader is also enabled (taking - factory reset state into account), however in this case discovery based on the loopback block device - .lo_name field is not enabled. + factory reset state into account, i.e. equivalent to root=gpt-auto), however in + this case discovery based on the loopback block device .lo_name field is not + enabled. The rootfstype= and rootflags= options are used to select the file system type and options when the root file system is automatically discovered. @@ -355,6 +382,24 @@ + + mount.usr= + mount.usrfstype= + mount.usrflags= + + Similar to root=, rootfstype=, + rootflags= (see above), but applies to the /usr/ partition + instead. Note that the gpt-auto, gpt-auto-force, + dissect-force settings that root= understands are not + supported by mount.usr= (however dissect is). + + Also note that automatic partition discovery for /usr/ must be enabled + explicitly, unlike the discovery for the root file system, which is enabled if no + root= paramater is passed at all. + + + + rw ro