Looks good.
Reviewed-by: William Kucharski <william.kucharski@xxxxxxxxxx>
> On Apr 19, 2023, at 6:09 AM, Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx> wrote:
>
> Commit "mm: return an ERR_PTR from __filemap_get_folio" changed from
> returning NULL to returning an ERR_PTR(). This cannot be fixed in either
> the ext4 tree or the mm tree, so this patch should be applied as part
> of merging the two trees.
>
> Reported-by: Eric Biggers <ebiggers@xxxxxxxxxx>
> Reported-by: syzbot+d1ae544e6e9dc29bcba5@xxxxxxxxxxxxxxxxxxxxxxxxx
> Debugged-by: William Kucharski <william.kucharski@xxxxxxxxxx>
> Signed-off-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
> ---
> v2: Fix typo
>
> fs/ext4/inline.c | 17 +++++++++--------
> fs/ext4/inode.c | 12 ++++++------
> fs/ext4/verity.c | 6 ++++--
> 3 files changed, 19 insertions(+), 16 deletions(-)
>
> diff --git a/fs/ext4/inline.c b/fs/ext4/inline.c
> index b9fb1177fff6..ab220d4bf73f 100644
> --- a/fs/ext4/inline.c
> +++ b/fs/ext4/inline.c
> @@ -566,8 +566,9 @@ static int ext4_convert_inline_data_to_extent(struct address_space *mapping,
> * started */
> folio = __filemap_get_folio(mapping, 0, FGP_WRITEBEGIN | FGP_NOFS,
> mapping_gfp_mask(mapping));
> - if (!folio) {
> - ret = -ENOMEM;
> + if (IS_ERR(folio)) {
> + ret = PTR_ERR(folio);
> + folio = NULL;
> goto out;
> }
>
> @@ -693,8 +694,8 @@ int ext4_try_to_write_inline_data(struct address_space *mapping,
>
> folio = __filemap_get_folio(mapping, 0, FGP_WRITEBEGIN | FGP_NOFS,
> mapping_gfp_mask(mapping));
> - if (!folio) {
> - ret = -ENOMEM;
> + if (IS_ERR(folio)) {
> + ret = PTR_ERR(folio);
> goto out;
> }
>
> @@ -854,8 +855,8 @@ static int ext4_da_convert_inline_data_to_extent(struct address_space *mapping,
>
> folio = __filemap_get_folio(mapping, 0, FGP_WRITEBEGIN,
> mapping_gfp_mask(mapping));
> - if (!folio)
> - return -ENOMEM;
> + if (IS_ERR(folio))
> + return PTR_ERR(folio);
>
> down_read(&EXT4_I(inode)->xattr_sem);
> if (!ext4_has_inline_data(inode)) {
> @@ -947,8 +948,8 @@ int ext4_da_write_inline_data_begin(struct address_space *mapping,
> */
> folio = __filemap_get_folio(mapping, 0, FGP_WRITEBEGIN | FGP_NOFS,
> mapping_gfp_mask(mapping));
> - if (!folio) {
> - ret = -ENOMEM;
> + if (IS_ERR(folio)) {
> + ret = PTR_ERR(folio);
> goto out_journal;
> }
>
> diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
> index 974747a6eb99..7626acc62f7c 100644
> --- a/fs/ext4/inode.c
> +++ b/fs/ext4/inode.c
> @@ -1177,8 +1177,8 @@ static int ext4_write_begin(struct file *file, struct address_space *mapping,
> retry_grab:
> folio = __filemap_get_folio(mapping, index, FGP_WRITEBEGIN,
> mapping_gfp_mask(mapping));
> - if (!folio)
> - return -ENOMEM;
> + if (IS_ERR(folio))
> + return PTR_ERR(folio);
> /*
> * The same as page allocation, we prealloc buffer heads before
> * starting the handle.
> @@ -2932,8 +2932,8 @@ static int ext4_da_write_begin(struct file *file, struct address_space *mapping,
> retry:
> folio = __filemap_get_folio(mapping, index, FGP_WRITEBEGIN,
> mapping_gfp_mask(mapping));
> - if (!folio)
> - return -ENOMEM;
> + if (IS_ERR(folio))
> + return PTR_ERR(folio);
>
> /* In case writeback began while the folio was unlocked */
> folio_wait_stable(folio);
> @@ -3675,8 +3675,8 @@ static int __ext4_block_zero_page_range(handle_t *handle,
> folio = __filemap_get_folio(mapping, from >> PAGE_SHIFT,
> FGP_LOCK | FGP_ACCESSED | FGP_CREAT,
> mapping_gfp_constraint(mapping, ~__GFP_FS));
> - if (!folio)
> - return -ENOMEM;
> + if (IS_ERR(folio))
> + return PTR_ERR(folio);
>
> blocksize = inode->i_sb->s_blocksize;
>
> diff --git a/fs/ext4/verity.c b/fs/ext4/verity.c
> index 3b01247066dd..ce4b720f19a1 100644
> --- a/fs/ext4/verity.c
> +++ b/fs/ext4/verity.c
> @@ -366,14 +366,16 @@ static struct page *ext4_read_merkle_tree_page(struct inode *inode,
> index += ext4_verity_metadata_pos(inode) >> PAGE_SHIFT;
>
> folio = __filemap_get_folio(inode->i_mapping, index, FGP_ACCESSED, 0);
> - if (!folio || !folio_test_uptodate(folio)) {
> + if (IS_ERR(folio) || !folio_test_uptodate(folio)) {
> DEFINE_READAHEAD(ractl, NULL, NULL, inode->i_mapping, index);
>
> - if (folio)
> + if (!IS_ERR(folio))
> folio_put(folio);
> 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 &folio->page;
> }
> return folio_file_page(folio, index);
> }
> --
> 2.39.2
>
