On Fri, Jul 24, 2020 at 06:45:00PM +0000, Satya Tangirala wrote: > Update the fscrypt documentation file for inline encryption support. > > Signed-off-by: Satya Tangirala <satyat@xxxxxxxxxx> > Reviewed-by: Eric Biggers <ebiggers@xxxxxxxxxx> > Reviewed-by: Jaegeuk Kim <jaegeuk@xxxxxxxxxx> > --- > Documentation/filesystems/fscrypt.rst | 16 +++++++++++++++- > 1 file changed, 15 insertions(+), 1 deletion(-) > > diff --git a/Documentation/filesystems/fscrypt.rst b/Documentation/filesystems/fscrypt.rst > index 1a6ad6f736b5..423c5a0daf45 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 > <https://github.com/tytso/xfstests-bld/blob/master/Documentation/kvm-quickstart.md>`_:: Since this patch is separate from the direct I/O support, I've applied it to fscrypt.git#master for 5.9. I'm not applying the direct I/O patches yet. - Eric
