I think I found why uswsusp is unable to resume when the swap partition is
on a lvm device, but I suspect that the problem lies with lvm2
and will have to be fixed either there or in initramfs-tools.
Essentially, when in the boot sequence scripts/local-top/lvm2 gets executed
in the ramdisk, it does not activate all available lvm devices, but rather
tries to individually activate the root device and the resume device,
calling the function activate_vg which is defined in the same script.
Now, what happens is that when activate_vg is called with a
/dev/mapper/something device as argument it works correctly; instead, when
it is given an argument "UUID=whateversensibleuuid" it fails to activate the
matching lvm partition, even if it exists in the system.
Now, since ROOT is defined by the argument provided in the kernel boot
command line, and since the grub scripts set it up to
/dev/mapper/rootvg-rootlvm, this works ok to activate the root partition.
Instead, the RESUME variable is set up in the conf/conf.d/resume
configuration file, which is magically set up by mkinitramfs to always be in
the form UUID=someuuid EVEN IF this was explicitly set in
/etc/initramfs-tools/conf/conf.d/resume as
RESUME=/dev/mapper/somecorrectlvmdevice
This happens in /usr/share/initramfs-tools/hooks/resume, which calls blkid
to translate _any_ candidate resume device found to UUID form. This is then
passed to activate_vg which fails to activate it.
Possible solutions I see:
1) The Right Thing: fix the function activate_vg in
/usr/share/initramfs-tools/scripts/local-top/lvm2 so that it activates an
lvm partition which is given in the form UUID=somecorrectlvmuuid
2) not too bad kludge: add a special case in
/usr/share/initramfs-tools/hooks/resume so that if a resume device is given
as /dev/mapper/something it is left alone and not forcibly translated to
UUID=correspondinguuid; this would make previously working configurations
(e.g. in which one had specified a correct RESUME line in
/etc/initramfs-tools/conf/conf.d/resume) happy again
3) atomic bomb approach: instead of going to great lengths to determine and
activate in the initramdisk only the root and resume lvm devices, just put
an unconditional
lvm vgchange -aly --ignorelockingfailure
line in /usr/share/initramfs-tools/scripts/local-top/lvm2, which will always
activate all lvm devices and be done with it.
I suggest that the uswsusp maintainer should relay this email (and/or his
own better analysis) to the maintainers of the lvm2 and initramfs-tools
packages, so that a common agreement can be found for a solution accepted by
all, which can hopefully be expected to work for some time and not be broken
time and again by some apparently unrelated change.
Bye
Giacomo
--
_________________________________________________________________
Giacomo Mulas <gmu...@oa-cagliari.inaf.it>
_________________________________________________________________
INAF - Osservatorio Astronomico di Cagliari
via della scienza * 09047 Selargius (CA)
Tel. (OAC): +39 329 6603810
Tel. (UNICA): +39 070 675 4916
_________________________________________________________________
"When the storms are raging around you, stay right where you are"
(Freddy Mercury)
_________________________________________________________________
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