Re: [PATCH] f2fs: allow readpages with NULL file pointer

[Chao Yu <chao@kernel.org>]

On 2017/9/21 13:00, gaoxiang (P) wrote:
> Keep in line with the other Linux file system implementations
> since page_cache_sync_readahead supports NULL file pointer,
> and thus we can readahead data by f2fs itself without file opening
> (something like the btrfs behavior).

Let's keep what it is until there is an example doing readahead passing @file
with NULL.

Thanks,

> 
> Signed-off-by: Gao Xiang <gaoxiang25@huawei.com>
> ---
>  fs/f2fs/data.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
> index 95f30f0..afa12f1 100644
> --- a/fs/f2fs/data.c
> +++ b/fs/f2fs/data.c
> @@ -1333,9 +1333,11 @@ static int f2fs_read_data_pages(struct file *file,
>  			struct address_space *mapping,
>  			struct list_head *pages, unsigned nr_pages)
>  {
> -	struct inode *inode = file->f_mapping->host;
> +	struct inode *inode = mapping->host;
>  	struct page *page = list_last_entry(pages, struct page, lru);
>  
> +	if (likely(file != NULL))
> +		BUG_ON(file->f_mapping != mapping);
>  	trace_f2fs_readpages(inode, page, nr_pages);
>  
>  	/* If the file has inline data, skip readpages */
> 

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