Hi. On Wed, 2005-07-13 at 08:51, Pavel Machek wrote: > Hi! > > > > | Update suspend documentation. > > > | > > > | Signed-off-by: Pavel Machek <[EMAIL PROTECTED]> > > > | > > > | --- > > > | > > > | diff --git a/Documentation/power/swsusp.txt > > > b/Documentation/power/swsusp.txt > > > | --- a/Documentation/power/swsusp.txt > > > | +++ b/Documentation/power/swsusp.txt > > > | @@ -318,3 +318,10 @@ As a rule of thumb use encrypted swap to > > > | system is shut down or suspended. Additionally use the encrypted > > > | suspend image to prevent sensitive data from being stolen after > > > | resume. > > > | + > > > | +Q: Why we cannot suspend to a swap file? > > > > > > Q: Why can't we suspend to a swap file? > > > or > > > Q: Why can we not suspend to a swap file? > > > > > > | + > > > | +A: Because accessing swap file needs the filesystem mounted, and > > > | +filesystem might do something wrong (like replaying the journal) > > > | +during mount. [Probably could be solved by modifying every filesystem > > > | +to support some kind of "really read-only!" option. Patches welcome.] > > > > This is wrong. Suspend2 has supported writing to a swap file for a long > > time (since 1.0), without requiring the filesystem to be mounted when > > resuming. We just need to store the bdev and block numbers in the image > > header. > > Uh, and then you pass something like resume=/dev/[EMAIL PROTECTED] on > command line? Okay, that could work. > > Does this look fair? > > Q: Why can't we suspend to a swap file? > > A: Because accessing swap file needs the filesystem mounted, and > filesystem might do something wrong (like replaying the journal) > during mount. > > There are few ways to get that fixed: > > 1) Probably could be solved by modifying every filesystem to support > some kind of "really read-only!" option. Patches welcome. > > 2) suspend2 gets around that by storing absolute positions in on-disk > image, with resume parameter pointing directly to suspend header.
And a block size. (It affects the interpretation of the block number). Apart from that, yes. Regards, Nigel -- Evolution. Enumerate the requirements. Consider the interdependencies. Calculate the probabilities. Be amazed that people believe it happened. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
