Re: [PATCH 25/26] xfs: make it possible to disable fsverity

["Darrick J. Wong" <djwong@kernel.org>]

On Wed, May 08, 2024 at 10:04:05PM -0700, Christoph Hellwig wrote:
> On Wed, May 08, 2024 at 01:31:48PM -0700, Darrick J. Wong wrote:
> > Hmm.  What if did something like what fsdax does to update the file
> > access methods?  We could clear the ondisk iflag but not the incore one;
> > set DONTCACHE on the dentry and the inode so that it will get reclaimed
> > ASAP instead of being put on the lru; and then tell userspace they have
> > to wait until the inode gets reclaimed and reloaded?
> 
> Yikes.  That's a completely mess I'd rather get rid of than add more of
> it.
> 
> What is the use case of disabling fsverity to start with vs just
> removing a fsverity enabled file after copying the content out?

How do you salvage the content of a fsverity file if the merkle tree
hashes don't match the data?  I'm thinking about the backup disk usecase
where you enable fsverity to detect bitrot in your video files but
they'd otherwise be mostly playable if it weren't for the EIO.

I guess you could always ddrescue the file, right?

--D