Ext4 and F2FS store verity metadata beyond i_size. This commit adds a
call back pointer to "struct fsverity_operations" which helps in
determining the the real file size limit upto which data can be read
from the file.
This call back will be required in order to get do_mpage_readpage()
to read files having verity metadata appended beyond i_size.
Signed-off-by: Chandan Rajendra <chan...@linux.ibm.com>
---
fs/ext4/super.c | 18 ++++++++++++++++++
include/linux/fsverity.h | 1 +
2 files changed, 19 insertions(+)
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index 63d73b360f1d..cadf50f9503f 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -1428,6 +1428,23 @@ static struct page
*ext4_read_verity_metadata_page(struct inode *inode,
return read_mapping_page(inode->i_mapping, index, NULL);
}
+static loff_t ext4_readpage_limit(struct inode *inode)
+{
+#ifdef CONFIG_FS_VERITY
+ if (IS_VERITY(inode)) {
+ if (inode->i_verity_info)
+ /* limit to end of metadata region */
+ return fsverity_full_i_size(inode);
+ /*
+ * fsverity_info is currently being set up and no user reads are
+ * allowed yet. It's easiest to just not enforce a limit yet.
+ */
+ return inode->i_sb->s_maxbytes;
+ }
+#endif
+ return i_size_read(inode);
+}
+
static bool ext4_verity_required(struct inode *inode, pgoff_t index)
{
return index < (i_size_read(inode) + PAGE_SIZE - 1) >> PAGE_SHIFT;
@@ -1438,6 +1455,7 @@ static const struct fsverity_operations ext4_verityops = {
.get_metadata_end = ext4_get_verity_metadata_end,
.read_metadata_page = ext4_read_verity_metadata_page,
.verity_required = ext4_verity_required,
+ .readpage_limit = ext4_readpage_limit,
};
#endif /* CONFIG_FS_VERITY */
diff --git a/include/linux/fsverity.h b/include/linux/fsverity.h
index b83712d6c79a..fc8113acbbfe 100644
--- a/include/linux/fsverity.h
+++ b/include/linux/fsverity.h
@@ -19,6 +19,7 @@ struct fsverity_operations {
int (*get_metadata_end)(struct inode *inode, loff_t *metadata_end_ret);
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);
};
#ifdef CONFIG_FS_VERITY
--
2.19.1
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