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Date: Tue, 09 Mar 2021 17:43:38 -0800
From: Dan Williams <dan.j.williams@...el.com>
To: linux-nvdimm@...ts.01.org
Cc: Christoph Hellwig <hch@....de>, Ming Lei <ming.lei@...hat.com>,
"Martin K. Petersen" <martin.petersen@...cle.com>,
Hannes Reinecke <hare@...e.de>, Jens Axboe <axboe@...nel.dk>,
kernel test robot <lkp@...el.com>,
Vishal Verma <vishal.l.verma@...el.com>,
linux-kernel@...r.kernel.org, linux-block@...r.kernel.org
Subject: [PATCH v2] 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")
Cc: Christoph Hellwig <hch@....de>
Cc: Ming Lei <ming.lei@...hat.com>
Cc: Martin K. Petersen <martin.petersen@...cle.com>
Cc: Hannes Reinecke <hare@...e.de>
Cc: Jens Axboe <axboe@...nel.dk>
Reported-by: kernel test robot <lkp@...el.com>
Reported-by: Vishal Verma <vishal.l.verma@...el.com>
Signed-off-by: Dan Williams <dan.j.williams@...el.com>
---
Changes since v1 [1]:
- Move from the sinking ship of revalidate_disk() to the local hotness
of nd_pmem_notify() (hch).
[1]: http://lore.kernel.org/r/161527286194.446794.5215036039655765042.stgit@dwillia2-desk3.amr.corp.intel.com
drivers/nvdimm/bus.c | 14 ++++++--------
drivers/nvdimm/pmem.c | 37 +++++++++++++++++++++++++++++++++----
drivers/nvdimm/region_devs.c | 7 +++++++
include/linux/nd.h | 1 +
4 files changed, 47 insertions(+), 12 deletions(-)
diff --git a/drivers/nvdimm/bus.c b/drivers/nvdimm/bus.c
index 48f0985ca8a0..3a777d0073b7 100644
--- a/drivers/nvdimm/bus.c
+++ b/drivers/nvdimm/bus.c
@@ -631,16 +631,14 @@ void nvdimm_check_and_set_ro(struct gendisk *disk)
struct nd_region *nd_region = to_nd_region(dev->parent);
int disk_ro = get_disk_ro(disk);
- /*
- * Upgrade to read-only if the region is read-only preserve as
- * read-only if the disk is already read-only.
- */
- if (disk_ro || nd_region->ro == disk_ro)
+ /* catch the disk up with the region ro state */
+ if (disk_ro == nd_region->ro)
return;
- dev_info(dev, "%s read-only, marking %s read-only\n",
- dev_name(&nd_region->dev), disk->disk_name);
- set_disk_ro(disk, 1);
+ dev_info(dev, "%s read-%s, marking %s read-%s\n",
+ dev_name(&nd_region->dev), nd_region->ro ? "only" : "write",
+ disk->disk_name, nd_region->ro ? "only" : "write");
+ set_disk_ro(disk, nd_region->ro);
}
EXPORT_SYMBOL(nvdimm_check_and_set_ro);
diff --git a/drivers/nvdimm/pmem.c b/drivers/nvdimm/pmem.c
index b8a85bfb2e95..7daac795db39 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);
diff --git a/drivers/nvdimm/region_devs.c b/drivers/nvdimm/region_devs.c
index ef23119db574..51870eb51da6 100644
--- a/drivers/nvdimm/region_devs.c
+++ b/drivers/nvdimm/region_devs.c
@@ -518,6 +518,12 @@ static ssize_t read_only_show(struct device *dev,
return sprintf(buf, "%d\n", nd_region->ro);
}
+static int revalidate_read_only(struct device *dev, void *data)
+{
+ nd_device_notify(dev, NVDIMM_REVALIDATE_REGION);
+ return 0;
+}
+
static ssize_t read_only_store(struct device *dev,
struct device_attribute *attr, const char *buf, size_t len)
{
@@ -529,6 +535,7 @@ static ssize_t read_only_store(struct device *dev,
return rc;
nd_region->ro = ro;
+ device_for_each_child(dev, NULL, revalidate_read_only);
return len;
}
static DEVICE_ATTR_RW(read_only);
diff --git a/include/linux/nd.h b/include/linux/nd.h
index cec526c8043d..ee9ad76afbba 100644
--- a/include/linux/nd.h
+++ b/include/linux/nd.h
@@ -11,6 +11,7 @@
enum nvdimm_event {
NVDIMM_REVALIDATE_POISON,
+ NVDIMM_REVALIDATE_REGION,
};
enum nvdimm_claim_class {
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