On Fri, Aug 23, 2024 at 09:08:09PM +0100, David Howells wrote:
> When AS_RELEASE_ALWAYS is set on a mapping, the ->release_folio() and
> ->invalidate_folio() calls should be invoked even if PG_private and
> PG_private_2 aren't set. This is used by netfslib to keep track of the
Should we update the comment in pagemap?
diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h
index 55b254d951da..18dd6174e6cc 100644
--- a/include/linux/pagemap.h
+++ b/include/linux/pagemap.h
@@ -204,7 +204,8 @@ enum mapping_flags {
AS_EXITING = 4, /* final truncate in progress */
/* writeback related tags are not used */
AS_NO_WRITEBACK_TAGS = 5,
- AS_RELEASE_ALWAYS = 6, /* Call ->release_folio(), even if no private data */
+ AS_RELEASE_ALWAYS = 6, /* Call ->release_folio() and ->invalidate_folio,
+ even if no private data */
AS_STABLE_WRITES = 7, /* must wait for writeback before modifying
folio contents */
AS_INACCESSIBLE = 8, /* Do not attempt direct R/W access to the mapping */
> point above which reads can be skipped in favour of just zeroing pagecache
> locally.
>
> There are a couple of places in truncation in which invalidation is only
> called when folio_has_private() is true. Fix these to check
> folio_needs_release() instead.
>
> Without this, the generic/075 and generic/112 xfstests (both fsx-based
> tests) fail with minimum folio size patches applied[1].
>
> Fixes: b4fa966f03b7 ("mm, netfs, fscache: stop read optimisation when folio removed from pagecache")
> Signed-off-by: David Howells <dhowells@xxxxxxxxxx>
> cc: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
> cc: Pankaj Raghav <p.raghav@xxxxxxxxxxx>
> cc: Jeff Layton <jlayton@xxxxxxxxxx>
> cc: Marc Dionne <marc.dionne@xxxxxxxxxxxx>
> cc: linux-afs@xxxxxxxxxxxxxxxxxxx
> cc: netfs@xxxxxxxxxxxxxxx
> cc: linux-mm@xxxxxxxxx
> cc: linux-fsdevel@xxxxxxxxxxxxxxx
> Link: https://lore.kernel.org/r/20240815090849.972355-1-kernel@xxxxxxxxxxxxxxxx/ [1]
> ---
> mm/truncate.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/mm/truncate.c b/mm/truncate.c
> index 4d61fbdd4b2f..0668cd340a46 100644
> --- a/mm/truncate.c
> +++ b/mm/truncate.c
> @@ -157,7 +157,7 @@ static void truncate_cleanup_folio(struct folio *folio)
> if (folio_mapped(folio))
> unmap_mapping_folio(folio);
>
> - if (folio_has_private(folio))
> + if (folio_needs_release(folio))
> folio_invalidate(folio, 0, folio_size(folio));
>
> /*
> @@ -219,7 +219,7 @@ bool truncate_inode_partial_folio(struct folio *folio, loff_t start, loff_t end)
> if (!mapping_inaccessible(folio->mapping))
> folio_zero_range(folio, offset, length);
>
> - if (folio_has_private(folio))
> + if (folio_needs_release(folio))
> folio_invalidate(folio, offset, length);
> if (!folio_test_large(folio))
> return true;
>
--
Pankaj Raghav
