[PATCH 01/11] fsverity: don't issue readahead for non-ENOENT errors from __filemap_get_folio

[Christoph Hellwig <hch@lst.de>]

Issuing more reads on errors is not a good idea, especially when the
most common error here is -ENOMEM.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 fs/verity/pagecache.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/fs/verity/pagecache.c b/fs/verity/pagecache.c
index 01c652bc802f..1a88decace53 100644
--- a/fs/verity/pagecache.c
+++ b/fs/verity/pagecache.c
@@ -22,7 +22,8 @@ struct page *generic_read_merkle_tree_page(struct inode *inode, pgoff_t index,
 	struct folio *folio;
 
 	folio = __filemap_get_folio(inode->i_mapping, index, FGP_ACCESSED, 0);
-	if (IS_ERR(folio) || !folio_test_uptodate(folio)) {
+	if (folio == ERR_PTR(-ENOENT) ||
+	    (!IS_ERR(folio) && !folio_test_uptodate(folio))) {
 		DEFINE_READAHEAD(ractl, NULL, NULL, inode->i_mapping, index);
 
 		if (!IS_ERR(folio))
@@ -30,9 +31,9 @@ struct page *generic_read_merkle_tree_page(struct inode *inode, pgoff_t index,
 		else if (num_ra_pages > 1)
 			page_cache_ra_unbounded(&ractl, num_ra_pages, 0);
 		folio = read_mapping_folio(inode->i_mapping, index, NULL);
-		if (IS_ERR(folio))
-			return ERR_CAST(folio);
 	}
+	if (IS_ERR(folio))
+		return ERR_CAST(folio);
 	return folio_file_page(folio, index);
 }
 EXPORT_SYMBOL_GPL(generic_read_merkle_tree_page);
-- 
2.47.3