Orange Pi5 kernel

^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  1) .. SPDX-License-Identifier: GPL-2.0
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  2) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  3) Verity files
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  4) ------------
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  5) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  6) ext4 supports fs-verity, which is a filesystem feature that provides
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  7) Merkle tree based hashing for individual readonly files.  Most of
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  8) fs-verity is common to all filesystems that support it; see
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  9) :ref:`Documentation/filesystems/fsverity.rst <fsverity>` for the
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 10) fs-verity documentation.  However, the on-disk layout of the verity
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 11) metadata is filesystem-specific.  On ext4, the verity metadata is
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 12) stored after the end of the file data itself, in the following format:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 13) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 14) - Zero-padding to the next 65536-byte boundary.  This padding need not
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 15)   actually be allocated on-disk, i.e. it may be a hole.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 16) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 17) - The Merkle tree, as documented in
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 18)   :ref:`Documentation/filesystems/fsverity.rst
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 19)   <fsverity_merkle_tree>`, with the tree levels stored in order from
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 20)   root to leaf, and the tree blocks within each level stored in their
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 21)   natural order.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 22) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 23) - Zero-padding to the next filesystem block boundary.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 24) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 25) - The verity descriptor, as documented in
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 26)   :ref:`Documentation/filesystems/fsverity.rst <fsverity_descriptor>`,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 27)   with optionally appended signature blob.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 28) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 29) - Zero-padding to the next offset that is 4 bytes before a filesystem
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 30)   block boundary.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 31) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 32) - The size of the verity descriptor in bytes, as a 4-byte little
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 33)   endian integer.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 34) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 35) Verity inodes have EXT4_VERITY_FL set, and they must use extents, i.e.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 36) EXT4_EXTENTS_FL must be set and EXT4_INLINE_DATA_FL must be clear.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 37) They can have EXT4_ENCRYPT_FL set, in which case the verity metadata
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 38) is encrypted as well as the data itself.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 39) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 40) Verity files cannot have blocks allocated past the end of the verity
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 41) metadata.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 42) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 43) Verity and DAX are not compatible and attempts to set both of these flags
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 44) on a file will fail.