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+.. SPDX-License-Identifier: GPL-2.0
+
+Verity files
+------------
+
+ext4 supports fs-verity, which is a filesystem feature that provides
+Merkle tree based hashing for individual readonly files.  Most of
+fs-verity is common to all filesystems that support it; see
+:ref:`Documentation/filesystems/fsverity.rst <fsverity>` for the
+fs-verity documentation.  However, the on-disk layout of the verity
+metadata is filesystem-specific.  On ext4, the verity metadata is
+stored after the end of the file data itself, in the following format:
+
+- Zero-padding to the next 65536-byte boundary.  This padding need not
+  actually be allocated on-disk, i.e. it may be a hole.
+
+- The Merkle tree, as documented in
+  :ref:`Documentation/filesystems/fsverity.rst
+  <fsverity_merkle_tree>`, with the tree levels stored in order from
+  root to leaf, and the tree blocks within each level stored in their
+  natural order.
+
+- Zero-padding to the next filesystem block boundary.
+
+- The verity descriptor, as documented in
+  :ref:`Documentation/filesystems/fsverity.rst <fsverity_descriptor>`,
+  with optionally appended signature blob.
+
+- Zero-padding to the next offset that is 4 bytes before a filesystem
+  block boundary.
+
+- The size of the verity descriptor in bytes, as a 4-byte little
+  endian integer.
+
+Verity inodes have EXT4_VERITY_FL set, and they must use extents, i.e.
+EXT4_EXTENTS_FL must be set and EXT4_INLINE_DATA_FL must be clear.
+They can have EXT4_ENCRYPT_FL set, in which case the verity metadata
+is encrypted as well as the data itself.
+
+Verity files cannot have blocks allocated past the end of the verity
+metadata.
+
+Verity and DAX are not compatible and attempts to set both of these flags
+on a file will fail.