Disable hibernation if swap is on file

Untested patch

Tested and works well for me.

Martin, since I have noticed you are in -proposed mode, I thought I'd subscribe you to this as well. I hope you do not mind. :P

This patch would be useful in hardy because hibernating a wubi installation might freeze the system, and users might then be inclined to hard reboot, which in turn might corrupt the filesystem (had someone complaining about it in the forum...).

Thanks

In general that looks fine. However, you should robustify it for the case that /proc/swaps does not exist for some reason (people might have disabled it in the kernel config, or whatever). Also, can you please open an upstream bug for it and link it here?

I'll sponsor this to intrepid and hardy-proposed after that. Thanks!

The debdiff for debian is a bit different from the above since it is against version 1.1.2.2

Accepted into -proposed, please test and give feedback here

Are there any instances of non wubi users having hibernation issues when using just swapfiles, or when using swap partitions and swapfiles?

@Martin, I tested the changes and they work for me.
@Vlowther, I am not sure how common it is for people to use swap files, but it certainly is very easy to replicate...

Copied to hardy-updates.

Should be fixed in Intrepid ASAP, too.

Martin see my patch for debian, that should also apply to intrepid (haven't actually tried though)

http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=484212

Taking for sponsoring.

Disabling hibernation if swap is on file - is it too aggressive approach? I mean, the crashes are reported to happen on Wubi only (where are the reports anyway?).

Some people use swap file only and there even was a discussion about using swap file as default in some distro since it make installation easier to newbies and has negligible speed impact (http://www.ussg.iu.edu/hypermail/linux/kernel/0507.0/1690.html).

This was actually uploaded a while ago already:

pm-utils (1.1.0-1ubuntu2) intrepid; urgency=low

  * 30-swap-file.patch: Added to disable hibernation when swap resides on a
    file.

 -- Evan Dandrea <email address hidden> Wed, 28 May 2008 10:59:14 -0400

Is this the current patch?
http://patches.ubuntu.com/p/pm-utils/extracted/30-swap-file.patch

User will have no idea why is hibernation disabled. What about documenting the patch?

 check_hibernate()
 {
- [ -f /sys/power/disk ] && grep -q disk /sys/power/state
+ # There has been rumor that hibernation of WUBI system (using swap file) causes freeze.
+ # See https://bugs.launchpad.net/debian/+source/pm-utils/+bug/224697
+ grep -q "/.*[[:space:]]file[[:space:]]" /proc/swaps && return 1
+ [ -f /sys/power/disk ] && grep -q disk /sys/power/state && return 0
 }

On Sun, 2008-10-05 at 19:29 +0000, PetrB wrote:
> Is this the current patch?
> http://patches.ubuntu.com/p/pm-utils/extracted/30-swap-file.patch
>
> User will have no idea why is hibernation disabled. What about
> documenting the patch?
>
> check_hibernate()
> {
> - [ -f /sys/power/disk ] && grep -q disk /sys/power/state
> + # There has been rumor that hibernation of WUBI system (using swap file) causes freeze.
> + # See https://bugs.launchpad.net/debian/+source/pm-utils/+bug/224697
> + grep -q "/.*[[:space:]]file[[:space:]]" /proc/swaps && return 1
> + [ -f /sys/power/disk ] && grep -q disk /sys/power/state && return 0
> }
I doubt documenting the patch will do any good in that aspect, although
it's always good to document the patch. The general user doesn't apt-get
source pm-utils to figure out why it doesn't hibernate.
--
Chow Loong Jin

I have used hibernation to a swapfile for some time without problems and thought the disabled hibernate was a bug (Bug 252143). So is there a way to reenable it?
The other really funny aspect here is: On a fresh ubuntu installation without any swapspace hibernate is not disabled, but after creating and activating the swap file, it is.

Agostino, why does this particularly affect wubi users? The recent comments seem to indicate that this should be reverted again.

This bug was fixed in the package pm-utils - 1.1.2.4-1ubuntu5

---------------
pm-utils (1.1.2.4-1ubuntu5) intrepid; urgency=low

  * Drop 30-swap-file.patch again. Reportedly, resuming from a swap file works
    just fine. (LP: #224697)

 -- Martin Pitt <email address hidden> Tue, 07 Oct 2008 19:44:20 +0200

Martin,

I didn't test hibernation on the latest intrepid (will do so in the coming days) but I am glad to hear that hibernation using a swap file now works. It is my understanding though that not all suspend (to disk) mechanisms do support swap on file, so it might be appropriate to test whether the current suspend app is indeed happy to use a swap file. Also, from what I gather from Johan's comment, we should test if there is a swap at all.

At least in uswsusp, you have to specify the "resume_offset" (0 for swap partition, but needs to be set for swap files). See http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=blob;f=Documentation/power/swsusp-and-swap-files.txt;h=f281886de4902041bbda38942772384a622d0319;hb=85ba94ba0592296053f7f2846812173424afe1cb and http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=blob;f=Documentation/power/userland-swsusp.txt;h=7b99636564c8cbc608ff6fb1a24b883c254bf8e3;hb=85ba94ba0592296053f7f2846812173424afe1cb