Greetings, we have discovered a shortcoming of the s390 support for supend to disk. The problem is that we currently do not save and restore the storage keys - the one additional byte associated with each 4K page, a unique property of s390. The resume from disk will read the hibernation image from disk and restore the original pages. The I/O or the memory move for safe pages will set the referenced and the dirty bit in the storage key for every restored page. Without a reset to the state before the hibernation cycle the pages will appear to be dirty which causes problems for e.g. read-only filesystems. The solution implemented with this patch saves the storage key in the upper 8 bits of the page-frame-numbers. The code adds 6 new function in kernel/power/snapshot.c which are conditionally defined with CONFIG_S390. The call sites of these functions are scattered in the snapshot code which makes it hard to find a better abstraction for the interface. The comments should make clear what the functions do. -- blue skies, Martin. "Reality continues to ruin my life." - Calvin. -- To unsubscribe from this list: send the line "unsubscribe linux-s390" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
