• Eric Biggers's avatar
    fscrypt: support test_dummy_encryption=v2 · ed318a6c
    Eric Biggers authored
    v1 encryption policies are deprecated in favor of v2, and some new
    features (e.g. encryption+casefolding) are only being added for v2.
    
    Therefore, the "test_dummy_encryption" mount option (which is used for
    encryption I/O testing with xfstests) needs to support v2 policies.
    
    To do this, extend its syntax to be "test_dummy_encryption=v1" or
    "test_dummy_encryption=v2".  The existing "test_dummy_encryption" (no
    argument) also continues to be accepted, to specify the default setting
    -- currently v1, but the next patch changes it to v2.
    
    To cleanly support both v1 and v2 while also making it easy to support
    specifying other encryption settings in the future (say, accepting
    "$contents_mode:$filenames_mode:v2"), make ext4 and f2fs maintain a
    pointer to the dummy fscrypt_context rather than using mount flags.
    
    To avoid concurrency issues, don't allow test_dummy_encryption to be set
    or changed during a remount.  (The former restriction is new, but
    xfstests doesn't run into it, so no one should notice.)
    
    Tested with 'gce-xfstests -c {ext4,f2fs}/encrypt -g auto'.  On ext4,
    there are two regressions, both of which are test bugs: ext4/023 and
    ext4/028 fail because they set an xattr and expect it to be stored
    inline, but the increase in size of the fscrypt_context from
    24 to 40 bytes causes this xattr to be spilled into an external block.
    
    Link: https://lore.kernel.org/r/20200512233251.118314-4-ebiggers@kernel.orgAcked-by: default avatarJaegeuk Kim <jaegeuk@kernel.org>
    Reviewed-by: default avatarTheodore Ts'o <tytso@mit.edu>
    Signed-off-by: default avatarEric Biggers <ebiggers@google.com>
    ed318a6c
f2fs.rst 35.2 KB