[PATCH v4 06/10] fs/dax: Implement dax_holder_operations

[Shiyang Ruan]

This is the case where the holder represents a filesystem.  The offset
translation from disk to block device is needed before we calling
->corrupted_range().

When a specific filesystem is being mounted, we use dax_set_holder() to
associate it with the dax_device.

Signed-off-by: Shiyang Ruan <ruansy.fnst@xxxxxxxxxxx>
---
 fs/dax.c            | 16 ++++++++++++++++
 include/linux/dax.h |  2 ++
 2 files changed, 18 insertions(+)

diff --git a/fs/dax.c b/fs/dax.c
index 58faca85455a..1a7473f46df2 100644
--- a/fs/dax.c
+++ b/fs/dax.c
@@ -1762,3 +1762,19 @@ vm_fault_t dax_finish_sync_fault(struct vm_fault *vmf,
 	return dax_insert_pfn_mkwrite(vmf, pfn, order);
 }
 EXPORT_SYMBOL_GPL(dax_finish_sync_fault);
+
+static int fs_dax_corrupted_range(struct dax_device *dax_dev,
+		struct block_device *bdev, loff_t offset, size_t size,
+		void *data)
+{
+	struct super_block *sb = dax_get_holder(dax_dev);
+	loff_t bdev_off = offset - (get_start_sect(bdev) << SECTOR_SHIFT);
+
+	if (!sb->s_op->corrupted_range)
+		return -EOPNOTSUPP;
+	return sb->s_op->corrupted_range(sb, bdev, bdev_off, size, data);
+}
+
+const struct dax_holder_operations fs_dax_holder_ops = {
+	.corrupted_range = fs_dax_corrupted_range,
+};
\ No newline at end of file
diff --git a/include/linux/dax.h b/include/linux/dax.h
index 6e758daa5004..b35b3b8959a5 100644
--- a/include/linux/dax.h
+++ b/include/linux/dax.h
@@ -254,6 +254,8 @@ static inline bool dax_mapping(struct address_space *mapping)
 	return mapping->host && IS_DAX(mapping->host);
 }
 
+extern const struct dax_holder_operations fs_dax_holder_ops;
+
 #ifdef CONFIG_DEV_DAX_HMEM_DEVICES
 void hmem_register_device(int target_nid, struct resource *r);
 #else
-- 
2.31.1