On Fri, May 15, 2020 at 06:49:16PM -0700, Eric Biggers wrote: > On Tue, May 12, 2020 at 10:43:17PM -0700, ira.weiny@xxxxxxxxx wrote: > > From: Ira Weiny <ira.weiny@xxxxxxxxx> > > > > Verity and DAX are incompatible. Changing the DAX mode due to a verity > > flag change is wrong without a corresponding address_space_operations > > update. > > > > Make the 2 options mutually exclusive by returning an error if DAX was > > set first. > > > > (Setting DAX is already disabled if Verity is set first.) > > > > Signed-off-by: Ira Weiny <ira.weiny@xxxxxxxxx> > > > > --- > > Changes: > > remove WARN_ON_ONCE > > Add documentation for DAX/Verity exclusivity > > --- > > Documentation/filesystems/ext4/verity.rst | 7 +++++++ > > fs/ext4/verity.c | 3 +++ > > 2 files changed, 10 insertions(+) > > > > diff --git a/Documentation/filesystems/ext4/verity.rst b/Documentation/filesystems/ext4/verity.rst > > index 3e4c0ee0e068..51ab1aa17e59 100644 > > --- a/Documentation/filesystems/ext4/verity.rst > > +++ b/Documentation/filesystems/ext4/verity.rst > > @@ -39,3 +39,10 @@ is encrypted as well as the data itself. > > > > Verity files cannot have blocks allocated past the end of the verity > > metadata. > > + > > +Verity and DAX > > +-------------- > > + > > +Verity and DAX are not compatible and attempts to set both of these flags on a > > +file will fail. > > + > > If you build the documentation, this shows up as its own subsection > "2.13. Verity and DAX" alongside "2.12. Verity files", which looks odd. > I think you should delete this new subsection header so that this paragraph goes > in the existing "Verity files" subsection. Ok... I'll fix it up... > > Also, Documentation/filesystems/fsverity.rst already mentions DAX (similar to > fscrypt.rst). Is it intentional that you added this to the ext4-specific > documentation instead? I proposed this text[1] and there were no objections... I was looking at ext4 because only ext4 supports verity and DAX. I think having this in both the ext4 docs and the verity docs helps. Ira [1] https://lore.kernel.org/lkml/20200415191451.GA2305801@xxxxxxxxxxxxxxxxxxxxxxxxx/ > > - Eric
