On Mon, Jan 26, 2026 at 05:50:53AM +0100, Christoph Hellwig wrote:
> Issuing more reads on errors is not a good idea, especially when the
> most common error here is -ENOMEM.
>
> Signed-off-by: Christoph Hellwig <[email protected]>
> ---
> fs/verity/pagecache.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/fs/verity/pagecache.c b/fs/verity/pagecache.c
> index 1efcdde20b73..63393f0f5834 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 (PTR_ERR(folio) == -ENOENT ||
> + !(IS_ERR(folio) && !folio_test_uptodate(folio))) {
I don't understand this logic at all. If @folio is actually an
ERR_PTR, then we dereference the non-folio to see if it's not uptodate?
I think (given the previous revisions) that what you want is to initiate
readahead if either there's no folio at all (ENOENT) or if there is a
folio but it's not uptodate? But not if there's some other error
(ENOMEM, EL3HLT, EFSCORRUPTED, etc)?
So maybe you want:
folio = __filemap_get_folio(...);
if (!IS_ERR(folio)) {
if (folio_test_uptodate(folio))
return folio_file_page(folio);
folio_put(folio);
} else if (PTR_ERR(folio) == -ENOENT) {
return ERR_CAST(folio);
}
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);
return folio_file_page(folio);
<confused>
--D
> DEFINE_READAHEAD(ractl, NULL, NULL, inode->i_mapping, index);
>
> if (!IS_ERR(folio))
> --
> 2.47.3
>
>
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