Re: [PATCH 08/15] fsverity: kick off hash readahead at data I/O submission time

[Christoph Hellwig <hch@lst.de>]

On Wed, Jan 28, 2026 at 03:22:13PM -0800, Darrick J. Wong wrote:
> > Unfortunately, this patch causes recursive down_read() of
> > address_space::invalidate_lock.  How was this meant to work?
> 
> Usually the filesystem calls filemap_invalidate_lock{,_shared} if it
> needs to coordinate truncate vs. page removal (i.e. fallocate hole
> punch).  That said, there are a few places where the pagecache itself
> will take that lock too...

> [...]

> ...except that pagecache_ra_unbounded is being called recursively from
> an actual file data read.  My guess is that we'd need a flag or
> something to ask for "unlocked" readahead if we still want readahead to
> spur more readahead.

Basically just move it out of page_cache_ra_unbounded.  With the
consolidation in the earlier patches there are just two callers
of page_cache_ra_unbounded left, this and the redirty_blocks() in f2fs.

I'd kinda wish to kill the latter, as the past-EOF reading is something
that should be restricted to core code, but I can't really think of
an easy way to do that.