On 10/01/2025 02:05, Matthew Wilcox wrote:
> On Thu, Jan 09, 2025 at 05:34:43PM +0000, Ryan Roberts wrote:
>> I started getting a different oops after I fixed this issue. It turns out that
>> __filemap_get_folio() returns ERR_PTR() on error whereas
>> grab_cache_page_nowait() (used previously) returns NULL. So the continue
>> condition needs to change. This fixes both for me:
>
> Hey Ryan, can you try this amalgam of three patches?
> If it works out, I'll send the two which aren't yet in akpm's tree to
> him.
Yep that fixes it. Feel free to add:
Tested-by: Ryan Roberts <ryan.roberts@xxxxxxx>
>
> diff --git a/fs/squashfs/file.c b/fs/squashfs/file.c
> index da25d6fa45ce..5ca2baa16dc2 100644
> --- a/fs/squashfs/file.c
> +++ b/fs/squashfs/file.c
> @@ -400,7 +400,7 @@ void squashfs_copy_cache(struct folio *folio,
> bytes -= PAGE_SIZE, offset += PAGE_SIZE) {
> struct folio *push_folio;
> size_t avail = buffer ? min(bytes, PAGE_SIZE) : 0;
> - bool uptodate = true;
> + bool updated = false;
>
> TRACE("bytes %zu, i %d, available_bytes %zu\n", bytes, i, avail);
>
> @@ -409,15 +409,15 @@ void squashfs_copy_cache(struct folio *folio,
> FGP_LOCK|FGP_CREAT|FGP_NOFS|FGP_NOWAIT,
> mapping_gfp_mask(mapping));
>
> - if (!push_folio)
> + if (IS_ERR(push_folio))
> continue;
>
> if (folio_test_uptodate(push_folio))
> goto skip_folio;
>
> - uptodate = squashfs_fill_page(push_folio, buffer, offset, avail);
> + updated = squashfs_fill_page(push_folio, buffer, offset, avail);
> skip_folio:
> - folio_end_read(push_folio, uptodate);
> + folio_end_read(push_folio, updated);
> if (i != folio->index)
> folio_put(push_folio);
> }
> diff --git a/mm/filemap.c b/mm/filemap.c
> index 12ba297bb85e..3b1eefa9aab8 100644
> --- a/mm/filemap.c
> +++ b/mm/filemap.c
> @@ -1505,7 +1505,7 @@ void folio_end_read(struct folio *folio, bool success)
> /* Must be in bottom byte for x86 to work */
> BUILD_BUG_ON(PG_uptodate > 7);
> VM_BUG_ON_FOLIO(!folio_test_locked(folio), folio);
> - VM_BUG_ON_FOLIO(folio_test_uptodate(folio), folio);
> + VM_BUG_ON_FOLIO(success && folio_test_uptodate(folio), folio);
>
> if (likely(success))
> mask |= 1 << PG_uptodate;
