[RFC PATCH 08/10] fsverity: Add call back to verify file holes

[Chandan Rajendra <chandan@linux.ibm.com>]

readpage() implmentations zero out part of the page-cache page mapping a
file hole. This commit adds a call back to "struct fsverity_operations"
which readpage() can invoke to verify the file hole.

Signed-off-by: Chandan Rajendra <chandan@linux.ibm.com>
---
 fs/ext4/super.c          | 1 +
 include/linux/fsverity.h | 1 +
 2 files changed, 2 insertions(+)

diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index 4493ddc357c6..94e0d4b56653 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -1459,6 +1459,7 @@ static const struct fsverity_operations ext4_verityops = {
 	.read_metadata_page	= ext4_read_verity_metadata_page,
 	.verity_required	= ext4_verity_required,
 	.readpage_limit		= ext4_readpage_limit,
+	.check_hole		= fsverity_check_hole,
 };
 #endif /* CONFIG_FS_VERITY */
 
diff --git a/include/linux/fsverity.h b/include/linux/fsverity.h
index fc8113acbbfe..8bc28b07d550 100644
--- a/include/linux/fsverity.h
+++ b/include/linux/fsverity.h
@@ -20,6 +20,7 @@ struct fsverity_operations {
 	struct page *(*read_metadata_page)(struct inode *inode, pgoff_t index);
 	bool (*verity_required)(struct inode *inode, pgoff_t index);
 	loff_t (*readpage_limit)(struct inode *inode);
+	bool (*check_hole)(struct inode *inode, struct page *page);
 };
 
 #ifdef CONFIG_FS_VERITY
-- 
2.19.1