linux-kernel - Re: [PATCH 1/2] erofs: avoid memory allocation failure during rolling decompression

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Message-ID: <20210305064549.GB3093390@xiangao.remote.csb>
Date:   Fri, 5 Mar 2021 14:45:49 +0800
From:   Gao Xiang <hsiangkao@...hat.com>
To:     Huang Jianan <huangjianan@...o.com>
Cc:     linux-erofs@...ts.ozlabs.org, linux-kernel@...r.kernel.org,
        guoweichao@...o.com, zhangshiming@...o.com
Subject: Re: [PATCH 1/2] erofs: avoid memory allocation failure during
 rolling decompression

On Fri, Mar 05, 2021 at 02:22:18PM +0800, Huang Jianan via Linux-erofs wrote:
> It should be better to ensure memory allocation during rolling
> decompression to avoid io error.

Currently, err would be treated as io error. Therefore, it'd be
better to ensure memory allocation during rolling decompression
to avoid such io error.

In the long term, we might consider adding another !Uptodate case
for such case.

> 
> Signed-off-by: Huang Jianan <huangjianan@...o.com>
> Signed-off-by: Guo Weichao <guoweichao@...o.com>
> ---
>  fs/erofs/decompressor.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/fs/erofs/decompressor.c b/fs/erofs/decompressor.c
> index 49347e681a53..fb0fa4e5b9ea 100644
> --- a/fs/erofs/decompressor.c
> +++ b/fs/erofs/decompressor.c
> @@ -86,7 +86,7 @@ static int z_erofs_lz4_prepare_destpages(struct z_erofs_decompress_req *rq,
>  			victim = availables[--top];
>  			get_page(victim);
>  		} else {
> -			victim = erofs_allocpage(pagepool, GFP_KERNEL);
> +			victim = erofs_allocpage(pagepool, GFP_KERNEL | __GFP_NOFAIL);

80 char limitation.

Thanks,
Gao Xiang

>  			if (!victim)
>  				return -ENOMEM;
>  			set_page_private(victim, Z_EROFS_SHORTLIVED_PAGE);
> -- 
> 2.25.1
>