libnvdimm: Notify disk drivers to revalidate region read-only
Previous kernels allowed the BLKROSET to override the disk's read-only
status. With that situation fixed the pmem driver needs to rely on
notification events to reevaluate the disk read-only status after the
host region has been marked read-write.
Recall that when libnvdimm determines that the persistent memory has
lost persistence (for example lack of energy to flush from DRAM to FLASH
on an NVDIMM-N device) it marks the region read-only, but that state can
be overridden by the user via:
echo 0 > /sys/bus/nd/devices/regionX/read_only
...to date there is no notification that the region has restored
persistence, so the user override is the only recovery.
Fixes: 52f019d43c22 ("block: add a hard-readonly flag to struct gendisk")
Reported-by: kernel test robot <lkp@intel.com>
Reported-by: Vishal Verma <vishal.l.verma@intel.com>
Tested-by: Vishal Verma <vishal.l.verma@intel.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Ming Lei <ming.lei@redhat.com>
Cc: Martin K. Petersen <martin.petersen@oracle.com>
Cc: Hannes Reinecke <hare@suse.de>
Cc: Jens Axboe <axboe@kernel.dk>
Link: https://lore.kernel.org/r/161534060720.528671.2341213328968989192.stgit@dwillia2-desk3.amr.corp.intel.com
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
diff --git a/drivers/nvdimm/pmem.c b/drivers/nvdimm/pmem.c
index b8a85bf..7daac79 100644
--- a/drivers/nvdimm/pmem.c
+++ b/drivers/nvdimm/pmem.c
@@ -26,6 +26,7 @@
#include <linux/mm.h>
#include <asm/cacheflush.h>
#include "pmem.h"
+#include "btt.h"
#include "pfn.h"
#include "nd.h"
@@ -585,7 +586,7 @@ static void nd_pmem_shutdown(struct device *dev)
nvdimm_flush(to_nd_region(dev->parent), NULL);
}
-static void nd_pmem_notify(struct device *dev, enum nvdimm_event event)
+static void pmem_revalidate_poison(struct device *dev)
{
struct nd_region *nd_region;
resource_size_t offset = 0, end_trunc = 0;
@@ -595,9 +596,6 @@ static void nd_pmem_notify(struct device *dev, enum nvdimm_event event)
struct range range;
struct kernfs_node *bb_state;
- if (event != NVDIMM_REVALIDATE_POISON)
- return;
-
if (is_nd_btt(dev)) {
struct nd_btt *nd_btt = to_nd_btt(dev);
@@ -635,6 +633,37 @@ static void nd_pmem_notify(struct device *dev, enum nvdimm_event event)
sysfs_notify_dirent(bb_state);
}
+static void pmem_revalidate_region(struct device *dev)
+{
+ struct pmem_device *pmem;
+
+ if (is_nd_btt(dev)) {
+ struct nd_btt *nd_btt = to_nd_btt(dev);
+ struct btt *btt = nd_btt->btt;
+
+ nvdimm_check_and_set_ro(btt->btt_disk);
+ return;
+ }
+
+ pmem = dev_get_drvdata(dev);
+ nvdimm_check_and_set_ro(pmem->disk);
+}
+
+static void nd_pmem_notify(struct device *dev, enum nvdimm_event event)
+{
+ switch (event) {
+ case NVDIMM_REVALIDATE_POISON:
+ pmem_revalidate_poison(dev);
+ break;
+ case NVDIMM_REVALIDATE_REGION:
+ pmem_revalidate_region(dev);
+ break;
+ default:
+ dev_WARN_ONCE(dev, 1, "notify: unknown event: %d\n", event);
+ break;
+ }
+}
+
MODULE_ALIAS("pmem");
MODULE_ALIAS_ND_DEVICE(ND_DEVICE_NAMESPACE_IO);
MODULE_ALIAS_ND_DEVICE(ND_DEVICE_NAMESPACE_PMEM);