• Eric Biggers's avatar
    ext4: only allow test_dummy_encryption when supported · 5f41fdae
    Eric Biggers authored
    Make the test_dummy_encryption mount option require that the encrypt
    feature flag be already enabled on the filesystem, rather than
    automatically enabling it.  Practically, this means that "-O encrypt"
    will need to be included in MKFS_OPTIONS when running xfstests with the
    test_dummy_encryption mount option.  (ext4/053 also needs an update.)
    
    Moreover, as long as the preconditions for test_dummy_encryption are
    being tightened anyway, take the opportunity to start rejecting it when
    !CONFIG_FS_ENCRYPTION rather than ignoring it.
    
    The motivation for requiring the encrypt feature flag is that:
    
    - Having the filesystem auto-enable feature flags is problematic, as it
      bypasses the usual sanity checks.  The specific issue which came up
      recently is that in kernel versions where ext4 supports casefold but
      not encrypt+casefold (v5.1 through v5.10), the kernel will happily add
      the encrypt flag to a filesystem that has the casefold flag, making it
      unmountable -- but only for subsequent mounts, not the initial one.
      This confused the casefold support detection in xfstests, causing
      generic/556 to fail rather than be skipped.
    
    - The xfstests-bld test runners (kvm-xfstests et al.) already use the
      required mkfs flag, so they will not be affected by this change.  Only
      users of test_dummy_encryption alone will be affected.  But, this
      option has always been for testing only, so it should be fine to
      require that the few users of this option update their test scripts.
    
    - f2fs already requires it (for its equivalent feature flag).
    Signed-off-by: default avatarEric Biggers <ebiggers@google.com>
    Reviewed-by: default avatarGabriel Krisman Bertazi <krisman@collabora.com>
    Link: https://lore.kernel.org/r/20220519204437.61645-1-ebiggers@kernel.orgSigned-off-by: default avatarTheodore Ts'o <tytso@mit.edu>
    5f41fdae
ext4.h 134 KB