[systemd-devel] [PATCHv5 0/3] hibernate-resume: implement support for resuming from hibernation

[Lennart Poettering]

On Tue, 26.08.14 23:53, Ivan Shapovalov (intelfx100 at gmail.com) wrote:

Looks great, wanted to commit. But the series doesn't apply to current
git. Could you please rebase?

Thanks!

> This patchset allows systemd to parse resume= kernel command line parameter
> and initiate resume from the specified device.
> 
> It adds:
> - a 'systemd-hibernate-resume' tool which takes path to a device node and
>   writes its major:minor to /sys/power/resume;
> - a corresponding 'systemd-hibernate-resume at .service' templated unit;
> - a 'systemd-hibernate-resume-generator' generator which parses the kernel
>   command line and instantiates the unit as necessary.
> 
> This functionality already exists in-kernel, but only for "/dev/sdXY"-style
> pathes. Implementing it in userspace allows to use arbitrary udev-created
> symlinks, e. g. persistent block device pathes ("/dev/disk/by-foo/bar") or
> fstab-like specifiers ("FOO=bar").
> 
> Userspace parsing of resume= kernel command line parameter has been
> traditionally done in initramfs via shell scripts (for Arch Linux, this is
> "resume" mkinitcpio hook), so I feel that this feature has its place within
> systemd.
> 
> Due to the nature of hibernation, the resume unit must be activated before
> any modifications to filesystems take place. This can happen only in initramfs
> before mounting anything.
> 
> So, first patch orders all non-root fsck after local-fs-pre.target, which in
> turn allows to order the resume unit before those fsck instances.
> 
> Second and third patches add the tool, the unit and the generator.
> 
> Thanks for reviewing!
> 
> v2: fix issues pointed out by Andrei:
>     - don't RemainAfterExit because it's useless
>     - don't attempt to resume outside of initramfs because it's unsafe
>       (reiserfs replays journal even if mounted RO)
> 
> v3: fix mistakes spotted by Thomas:
>     - return 0 in main path of resume.c:process_resume()
>     - fix type and add missing cleanup attribute in resume-generator.c:main()
> 
> v4: drop the [RFC] prefix as there are no more issues with this approach;
>     incorporate feedback from Lennart:
>     - fix indentation in resume-generator.c:parse_proc_cmdline_item()
>     - remove overly aggressive 80-column line breaks
>     - don't Before=usr.mount and After=systemd-udevd.service
>       as the respective configurations are deemed broken
>     - reword the "Failed to resume" message and downgrade it to log_info()
> 
> v5: add the binaries and preprocessed unit to respective .gitignore files
>     incorporate feedback from Lennart:
>     - rename systemd-resume-* to systemd-hibernate-resume-*
>     incorporate feedback from Dave:
>     - use fstab_node_to_udev_node() in the generator to also handle fstab-like
>       specifiers
> 
> Ivan Shapovalov (3):
>   units: order systemd-fsck at .service after local-fs-pre.target.
>   hibernate-resume: add a tool to write a device node's major:minor to /sys/power/resume.
>   hibernate-resume-generator: add a generator for instantiating the resume unit.
> 
>  .gitignore                                 |  2 +
>  Makefile-man.am                            | 21 +++----
>  Makefile.am                                | 28 +++++++--
>  man/kernel-command-line.xml                | 14 ++++-
>  man/systemd-hibernate-resume-generator.xml | 93 +++++++++++++++++++++++++++++
>  man/systemd-hibernate-resume at .service.xml  | 81 +++++++++++++++++++++++++
>  src/hibernate-resume/Makefile              |  1 +
>  src/hibernate-resume/hibernate-resume.c    | 81 +++++++++++++++++++++++++
>  src/resume-generator/Makefile              |  1 +
>  src/resume-generator/resume-generator.c    | 95 ++++++++++++++++++++++++++++++
>  units/.gitignore                           |  1 +
>  units/systemd-fsck at .service.in             |  2 +-
>  units/systemd-hibernate-resume at .service.in | 20 +++++++
>  13 files changed, 422 insertions(+), 18 deletions(-)
>  create mode 100644 man/systemd-hibernate-resume-generator.xml
>  create mode 100644 man/systemd-hibernate-resume at .service.xml
>  create mode 120000 src/hibernate-resume/Makefile
>  create mode 100644 src/hibernate-resume/hibernate-resume.c
>  create mode 120000 src/resume-generator/Makefile
>  create mode 100644 src/resume-generator/resume-generator.c
>  create mode 100644 units/systemd-hibernate-resume at .service.in
> 


Lennart

-- 
Lennart Poettering, Red Hat