1 .. SPDX-License-Identifier: GPL-2.0
2
3 Verity files
4 ------------
5
6 ext4 supports fs-verity, which is a filesystem
7 Merkle tree based hashing for individual reado
8 fs-verity is common to all filesystems that su
9 :ref:`Documentation/filesystems/fsverity.rst <
10 fs-verity documentation. However, the on-disk
11 metadata is filesystem-specific. On ext4, the
12 stored after the end of the file data itself,
13
14 - Zero-padding to the next 65536-byte boundary
15 actually be allocated on-disk, i.e. it may b
16
17 - The Merkle tree, as documented in
18 :ref:`Documentation/filesystems/fsverity.rst
19 <fsverity_merkle_tree>`, with the tree level
20 root to leaf, and the tree blocks within eac
21 natural order.
22
23 - Zero-padding to the next filesystem block bo
24
25 - The verity descriptor, as documented in
26 :ref:`Documentation/filesystems/fsverity.rst
27 with optionally appended signature blob.
28
29 - Zero-padding to the next offset that is 4 by
30 block boundary.
31
32 - The size of the verity descriptor in bytes,
33 endian integer.
34
35 Verity inodes have EXT4_VERITY_FL set, and the
36 EXT4_EXTENTS_FL must be set and EXT4_INLINE_DA
37 They can have EXT4_ENCRYPT_FL set, in which ca
38 is encrypted as well as the data itself.
39
40 Verity files cannot have blocks allocated past
41 metadata.
42
43 Verity and DAX are not compatible and attempts
44 on a file will fail.
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