[PATCH 1/4] libnvdimm: add a ro state control function for nvdimm

From: Huaisheng Ye
Date: Wed Oct 27 2021 - 08:09:47 EST


libndctl failed to pass when writing pmem disk.
Here is the error message below,

namespace6.0: failed to write /dev/pmem6
check_namespaces: namespace6.0 validate_bdev failed
ndctl-test1 failed: -6

Commit 98f49b63e84d4ee1a5c327d0b5f4e8699f6c70fe removes set_device_ro and
e00adcadf3af7a8335026d71ab9f0e0a922191ac adds a new set_read_only method
to allow for driver-specific processing when changing the block device's
read-only state.

Current drivers nd_pmem, nd_blk and nd_btt don't have the capability to
enable or disable write protect (read-only) state. Without that,
blkdev_roset just modifies the value of bd_read_only of struct block_device
and returns success to ioctl of block device. Error would happen when writing
read-only disk next.

Add ro state control function in libnvdimm for this purpose.

Signed-off-by: Huaisheng Ye <huaisheng.ye@xxxxxxxxx>
---
drivers/nvdimm/bus.c | 17 +++++++++++++++++
drivers/nvdimm/nd.h | 1 +
2 files changed, 18 insertions(+)

diff --git a/drivers/nvdimm/bus.c b/drivers/nvdimm/bus.c
index 9dc7f3edd42b..299dd5e11ae7 100644
--- a/drivers/nvdimm/bus.c
+++ b/drivers/nvdimm/bus.c
@@ -636,6 +636,23 @@ void nvdimm_check_and_set_ro(struct gendisk *disk)
}
EXPORT_SYMBOL(nvdimm_check_and_set_ro);

+int nd_set_ro(struct block_device *bdev, bool ro)
+{
+ struct gendisk *disk = bdev->bd_disk;
+ struct device *dev = disk_to_dev(disk)->parent;
+ int disk_ro = get_disk_ro(disk);
+
+ /* nothing to change with ro state */
+ if (disk_ro == ro)
+ return 0;
+
+ dev_info(dev, "set %s to read-%s\n",
+ disk->disk_name, ro ? "only" : "write");
+ set_disk_ro(disk, ro);
+ return 0;
+}
+EXPORT_SYMBOL(nd_set_ro);
+
static ssize_t modalias_show(struct device *dev, struct device_attribute *attr,
char *buf)
{
diff --git a/drivers/nvdimm/nd.h b/drivers/nvdimm/nd.h
index 5467ebbb4a6b..f1cf3eb21292 100644
--- a/drivers/nvdimm/nd.h
+++ b/drivers/nvdimm/nd.h
@@ -512,6 +512,7 @@ void nvdimm_bus_lock(struct device *dev);
void nvdimm_bus_unlock(struct device *dev);
bool is_nvdimm_bus_locked(struct device *dev);
void nvdimm_check_and_set_ro(struct gendisk *disk);
+int nd_set_ro(struct block_device *bdev, bool ro);
void nvdimm_drvdata_release(struct kref *kref);
void put_ndd(struct nvdimm_drvdata *ndd);
int nd_label_reserve_dpa(struct nvdimm_drvdata *ndd);
--
2.27.0