Re: [f2fs-dev] [PATCH v2] f2fs: fix hungtask when decompressed fail

[Eric Biggers <ebiggers@kernel.org>]

On Wed, Jun 08, 2022 at 09:48:52PM +0800, Fengnan Chang wrote:
> When decompressed failed, f2fs_prepare_compress_overwrite will enter
> endless loop, may casue hungtask.
> 
> [   14.088665] F2FS-fs (nvme0n1): lz4 decompress failed, ret:-4155
> [   14.089851] F2FS-fs (nvme0n1): lz4 decompress failed, ret:-4155
> 
> Signed-off-by: Fengnan Chang <fengnanchang@gmail.com>

This commit message only explains the problem, not the solution.  It should
explain the solution too.

Also, if it's fixing a bug, it needs 'Fixes' and 'Cc stable' tags.

> diff --git a/fs/f2fs/compress.c b/fs/f2fs/compress.c
> index 24824cd96f36..1764e3859262 100644
> --- a/fs/f2fs/compress.c
> +++ b/fs/f2fs/compress.c
> @@ -1060,7 +1060,7 @@ static int prepare_compress_overwrite(struct compress_ctx *cc,
>  	sector_t last_block_in_bio;
>  	unsigned fgp_flag = FGP_LOCK | FGP_WRITE | FGP_CREAT;
>  	pgoff_t start_idx = start_idx_of_cluster(cc);
> -	int i, ret;
> +	int i, ret, retry_count = 3;
>  
>  retry:
>  	ret = f2fs_is_compressed_cluster(cc->inode, start_idx);
> @@ -1120,7 +1120,12 @@ static int prepare_compress_overwrite(struct compress_ctx *cc,
>  			f2fs_put_rpages(cc);
>  			f2fs_unlock_rpages(cc, i + 1);
>  			f2fs_destroy_compress_ctx(cc, true);
> -			goto retry;
> +			retry_count--;
> +			if (PageError(page) && !retry_count) {
> +				ret = -EIO;
> +				goto out;
> +			} else

What is the purpose of using PG_error here?

- Eric


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