[RFC PATCH v3 6/9] pmem: Implement ->corrupted_range() for pmem driver

[Shiyang Ruan <ruansy.fnst@xxxxxxxxxxxxxx>]

Obtain the superblock of a pmem disk, and call filesystem's
->corrupted_range() to handle the corrupted data.

Signed-off-by: Shiyang Ruan <ruansy.fnst@xxxxxxxxxxxxxx>
---
 block/genhd.c         | 12 ++++++++++++
 drivers/nvdimm/pmem.c | 24 ++++++++++++++++++++++++
 include/linux/genhd.h |  1 +
 3 files changed, 37 insertions(+)

diff --git a/block/genhd.c b/block/genhd.c
index 9387f050c248..436adce123b2 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -1058,6 +1058,18 @@ struct block_device *bdget_disk(struct gendisk *disk, int partno)
 }
 EXPORT_SYMBOL(bdget_disk);
 
+struct block_device *bdget_disk_sector(struct gendisk *disk, sector_t sector)
+{
+	struct block_device *bdev = NULL;
+	struct hd_struct *part = disk_map_sector_rcu(disk, sector);
+
+	if (part)
+		bdev = bdget_part(part);
+
+	return bdev;
+}
+EXPORT_SYMBOL(bdget_disk_sector);
+
 /*
  * print a full list of all partitions - intended for places where the root
  * filesystem can't be mounted and thus to give the victim some idea of what
diff --git a/drivers/nvdimm/pmem.c b/drivers/nvdimm/pmem.c
index 4a114937c43b..4688bff19c20 100644
--- a/drivers/nvdimm/pmem.c
+++ b/drivers/nvdimm/pmem.c
@@ -253,6 +253,29 @@ static int pmem_rw_page(struct block_device *bdev, sector_t sector,
 	return blk_status_to_errno(rc);
 }
 
+static int pmem_corrupted_range(struct gendisk *disk, struct block_device *bdev,
+				loff_t disk_offset, size_t len, void *data)
+{
+	struct super_block *sb;
+	loff_t bdev_offset;
+	sector_t disk_sector = disk_offset >> SECTOR_SHIFT;
+	int rc = 0;
+
+	bdev = bdget_disk_sector(disk, disk_sector);
+	if (!bdev)
+		return -ENODEV;
+
+	bdev_offset = (disk_sector - get_start_sect(bdev)) << SECTOR_SHIFT;
+	sb = get_super(bdev);
+	if (sb && sb->s_op->corrupted_range) {
+		rc = sb->s_op->corrupted_range(sb, bdev, bdev_offset, len, data);
+		drop_super(sb);
+	}
+
+	bdput(bdev);
+	return rc;
+}
+
 /* see "strong" declaration in tools/testing/nvdimm/pmem-dax.c */
 __weak long __pmem_direct_access(struct pmem_device *pmem, pgoff_t pgoff,
 		long nr_pages, void **kaddr, pfn_t *pfn)
@@ -281,6 +304,7 @@ static const struct block_device_operations pmem_fops = {
 	.owner =		THIS_MODULE,
 	.submit_bio =		pmem_submit_bio,
 	.rw_page =		pmem_rw_page,
+	.corrupted_range =	pmem_corrupted_range,
 };
 
 static int pmem_dax_zero_page_range(struct dax_device *dax_dev, pgoff_t pgoff,
diff --git a/include/linux/genhd.h b/include/linux/genhd.h
index 03da3f603d30..ed06209008b8 100644
--- a/include/linux/genhd.h
+++ b/include/linux/genhd.h
@@ -303,6 +303,7 @@ static inline void add_disk_no_queue_reg(struct gendisk *disk)
 extern void del_gendisk(struct gendisk *gp);
 extern struct gendisk *get_gendisk(dev_t dev, int *partno);
 extern struct block_device *bdget_disk(struct gendisk *disk, int partno);
+extern struct block_device *bdget_disk_sector(struct gendisk *disk, sector_t sector);
 
 extern void set_device_ro(struct block_device *bdev, int flag);
 extern void set_disk_ro(struct gendisk *disk, int flag);
-- 
2.29.2