docs: fs-verity: mention statx() support
Document that the statx() system call can now be used to check whether a
file is a verity file.
Signed-off-by: Eric Biggers <ebiggers@google.com>
diff --git a/Documentation/filesystems/fsverity.rst b/Documentation/filesystems/fsverity.rst
index dd55204..a95536b 100644
--- a/Documentation/filesystems/fsverity.rst
+++ b/Documentation/filesystems/fsverity.rst
@@ -226,6 +226,14 @@
The verity flag is not settable via FS_IOC_SETFLAGS. You must use
FS_IOC_ENABLE_VERITY instead, since parameters must be provided.
+statx
+-----
+
+Since Linux v5.5, the statx() system call sets STATX_ATTR_VERITY if
+the file has fs-verity enabled. This can perform better than
+FS_IOC_GETFLAGS and FS_IOC_MEASURE_VERITY because it doesn't require
+opening the file, and opening verity files can be expensive.
+
Accessing verity files
======================