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[v2,6/7] fscrypt: document inline encryption support

Message ID 20200717013518.59219-7-satyat@google.com
State Superseded
Headers show
Series add support for direct I/O with fscrypt using blk-crypto | expand

Commit Message

Satya Tangirala July 17, 2020, 1:35 a.m. UTC
Update the fscrypt documentation file for inline encryption support.

Signed-off-by: Satya Tangirala <satyat@google.com>
 Documentation/filesystems/fscrypt.rst | 16 +++++++++++++++-
 1 file changed, 15 insertions(+), 1 deletion(-)
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diff --git a/Documentation/filesystems/fscrypt.rst b/Documentation/filesystems/fscrypt.rst
index f5d8b0303ddf..f3d87a1a0a7f 100644
--- a/Documentation/filesystems/fscrypt.rst
+++ b/Documentation/filesystems/fscrypt.rst
@@ -1204,6 +1204,18 @@  buffer.  Some filesystems, such as UBIFS, already use temporary
 buffers regardless of encryption.  Other filesystems, such as ext4 and
 F2FS, have to allocate bounce pages specially for encryption.
+Fscrypt is also able to use inline encryption hardware instead of the
+kernel crypto API for en/decryption of file contents.  When possible, and
+if directed to do so (by specifying the 'inlinecrypt' mount option for
+an ext4/F2FS filesystem), it adds encryption contexts to bios and
+uses blk-crypto to perform the en/decryption instead of making use
+of the above read/write path changes.  Of course, even if directed to make
+use of inline encryption, fscrypt will only be able to do so if either
+hardware inline encryption support is available for the selected encryption
+algorithm or CONFIG_BLK_INLINE_ENCRYPTION_FALLBACK is selected.  If neither
+is the case, fscrypt will fall back to using the above mentioned read/write
+path changes for en/decryption.
 Filename hashing and encoding
@@ -1250,7 +1262,9 @@  Tests
 To test fscrypt, use xfstests, which is Linux's de facto standard
 filesystem test suite.  First, run all the tests in the "encrypt"
-group on the relevant filesystem(s).  For example, to test ext4 and
+group on the relevant filesystem(s).  One can also run the tests
+with the 'inlinecrypt' mount option to test the implementation for
+inline encryption support.  For example, to test ext4 and
 f2fs encryption using `kvm-xfstests