On Fri 2009-11-13 21:05:07, Rafael J. Wysocki wrote: > On Thursday 12 November 2009, Thomas Petazzoni wrote: > > Hello, > > > > Thanks for your feedback. > > > > Le Thu, 12 Nov 2009 21:52:02 +0100, > > "Rafael J. Wysocki" <rjw@xxxxxxx> a ??crit : > > > > > The userspace interface doesn't really allow you to write to a file. > > > You can write into the area the file occupies on the partition, but > > > you can't use the filesystem code for the actual writing. At least > > > you shouldn't do that. > > > > Ah. But it seems to work fairly nicely. Why can't the filesystem code > > could be used to store the resume image ? Note that my file is stored > > in a separate partition, fully dedicated to storing the resume file and > > mounted only at very specific points in the system lifetime. > > That doesn't really matter. > > The problem is that the image is likely to contain filesystem data (eg. > superblocks etc.) that correspond to the state before the image has been > created. Now, your using the filesystem code for writing the image modifies > the on-disk metadata which become inconsistent with the filesystem data in > the image. This inconsistencies may very well result in an unfixable > corruption of the file system after the resume (that actually happened to > a number of people, so it's not just pure theory). > > That really depends on the fileystem used, though. But based on his description... if fs is only mounted after atomic snapshot... it actually should be safe. Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html _______________________________________________ linux-pm mailing list linux-pm@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/linux-pm
