Pankaj reports that starting with commit ad428cdb525a "dax: Check the end of the block-device capacity with dax_direct_access()" device-mapper no longer allows dax operation. This results from the stricter checks in __bdev_dax_supported() that validate that the start and end of a block-device map to the same 'pagemap' instance.
Teach the dax-core and device-mapper to validate the 'pagemap' on a per-target basis. This is accomplished by refactoring the bdev_dax_supported() internals into generic_fsdax_supported() which takes a sector range to validate. Consequently generic_fsdax_supported() is suitable to be used in a device-mapper ->iterate_devices() callback. A new ->dax_supported() operation is added to allow composite devices to split and route upper-level bdev_dax_supported() requests.
Fixes: ad428cdb525a ("dax: Check the end of the block-device...") Cc: stable@vger.kernel.org Cc: Jan Kara jack@suse.cz Cc: Ira Weiny ira.weiny@intel.com Cc: Dave Jiang dave.jiang@intel.com Cc: Mike Snitzer snitzer@redhat.com Cc: Keith Busch keith.busch@intel.com Cc: Matthew Wilcox willy@infradead.org Cc: Vishal Verma vishal.l.verma@intel.com Cc: Heiko Carstens heiko.carstens@de.ibm.com Cc: Martin Schwidefsky schwidefsky@de.ibm.com Reported-by: Pankaj Gupta pagupta@redhat.com Signed-off-by: Dan Williams dan.j.williams@intel.com
Thank you for the patch. Looks good to me. I also tested the patch and it works well.
Reviewed-and-Tested-by: Pankaj Gupta pagupta@redhat.com
Best regards, Pankaj