Re: [f2fs-dev] [PATCH v2 2/2] f2fs: support POSIX_FADV_DONTNEED drop compressed page cache

[Chao Yu <chao@kernel.org>]

On 2021/11/26 18:19, Fengnan Chang wrote:
> Previously, compressed page cache drop when clean page cache, but
> POSIX_FADV_DONTNEED can't clean compressed page cache because raw page
> don't have private data, and won't call f2fs_invalidate_compress_pages.
> This commit call f2fs_invalidate_compress_pages() directly in
> f2fs_file_fadvise() for POSIX_FADV_DONTNEED case.
> 
> Signed-off-by: Fengnan Chang <changfengnan@vivo.com>
> ---
>   fs/f2fs/file.c | 7 +++++--
>   1 file changed, 5 insertions(+), 2 deletions(-)
> 
> diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
> index 32c0bd545c5c..dafdaad9a9e4 100644
> --- a/fs/f2fs/file.c
> +++ b/fs/f2fs/file.c
> @@ -4677,12 +4677,11 @@ static ssize_t f2fs_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
>   static int f2fs_file_fadvise(struct file *filp, loff_t offset, loff_t len,
>   		int advice)
>   {
> -	struct inode *inode;
>   	struct address_space *mapping;
>   	struct backing_dev_info *bdi;
> +	struct inode *inode = file_inode(filp);
>   
>   	if (advice == POSIX_FADV_SEQUENTIAL) {
> -		inode = file_inode(filp);
>   		if (S_ISFIFO(inode->i_mode))
>   			return -ESPIPE;
>   
> @@ -4697,6 +4696,10 @@ static int f2fs_file_fadvise(struct file *filp, loff_t offset, loff_t len,
>   		filp->f_mode &= ~FMODE_RANDOM;
>   		spin_unlock(&filp->f_lock);
>   		return 0;
> +	} else if (advice == POSIX_FADV_DONTNEED) {
> +		if (test_opt(F2FS_I_SB(inode), COMPRESS_CACHE) &&
> +			f2fs_compressed_file(inode))
> +			f2fs_invalidate_compress_pages(F2FS_I_SB(inode), inode->i_ino);
>   	}

Well, how about invalidating compressed pages after generic_fadvise() in order to
check inode status before dropping caches?

Thanks,

>   
>   	return generic_fadvise(filp, offset, len, advice);
> 


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