Re: [PATCH v2 00/23] fs-verity support for XFS

Christoph Hellwig
2023-04-12T12:42:40Z

On Wed, Apr 12, 2023 at 01:18:26PM +1000, Dave Chinner wrote:
> Right. It's not entirely simple to store metadata on disk beyond EOF
> in XFS because of all the assumptions throughout the IO path and
> allocator interfaces that it can allocate space beyond EOF at will
> and something else will clean it up later if it is not needed. This
> impacts on truncate, delayed allocation, writeback, IO completion,
> EOF block removal on file close, background garbage collection,
> ENOSPC/EDQUOT driven space freeing, etc. Some of these things cross
> over into iomap infrastructure, too.

To me that actually makes it easier to support the metadata beyond
i_size. Remember that the file is immutable after add fsverity
hash is added. So basically we just need to skip freeing the
eofblocks if that flag is set.