Re: [PATCH] zonefs: Always invalidate last cache page on append write

[Hans Holmberg <hans@owltronix.com>]

Applied the patch on top of 6.3.0-rc4 and it solves the corruption issue I saw,
Tested-by: Hans Holmberg <hans.holmberg@wdc.com>

Cheers!

On Wed, Mar 29, 2023 at 7:58 AM Damien Le Moal
<damien.lemoal@opensource.wdc.com> wrote:
>
> When a direct append write is executed, the append offset may correspond
> to the last page of an inode which might have been cached already by
> buffered reads, page faults with mmap-read or non-direct readahead.
> To ensure that the on-disk and cached data is consistant for such last
> cached page, make sure to always invalidate it in
> zonefs_file_dio_append(). This invalidation will always be a no-op when
> the device block size is equal to the page size (e.g. 4K).
>
> Reported-by: Hans Holmberg <Hans.Holmberg@wdc.com>
> Fixes: 02ef12a663c7 ("zonefs: use REQ_OP_ZONE_APPEND for sync DIO")
> Cc: stable@vger.kernel.org
> Signed-off-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
> ---
>  fs/zonefs/file.c | 12 ++++++++++++
>  1 file changed, 12 insertions(+)
>
> diff --git a/fs/zonefs/file.c b/fs/zonefs/file.c
> index 617e4f9db42e..eeab8b93493b 100644
> --- a/fs/zonefs/file.c
> +++ b/fs/zonefs/file.c
> @@ -390,6 +390,18 @@ static ssize_t zonefs_file_dio_append(struct kiocb *iocb, struct iov_iter *from)
>         max = ALIGN_DOWN(max << SECTOR_SHIFT, inode->i_sb->s_blocksize);
>         iov_iter_truncate(from, max);
>
> +       /*
> +        * If the inode block size (sector size) is smaller than the
> +        * page size, we may be appending data belonging to an already
> +        * cached last page of the inode. So make sure to invalidate that
> +        * last cached page. This will always be a no-op for the case where
> +        * the block size is equal to the page size.
> +        */
> +       ret = invalidate_inode_pages2_range(inode->i_mapping,
> +                                           iocb->ki_pos >> PAGE_SHIFT, -1);
> +       if (ret)
> +               return ret;
> +
>         nr_pages = iov_iter_npages(from, BIO_MAX_VECS);
>         if (!nr_pages)
>                 return 0;
> --
> 2.39.2
>