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

[Chao Yu <chao@kernel.org>]

On 2022/6/8 2:45, Jaegeuk Kim wrote:
> On 05/11, 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>
>> ---
>>   fs/f2fs/compress.c | 9 +++++++--
>>   1 file changed, 7 insertions(+), 2 deletions(-)
>>
>> diff --git a/fs/f2fs/compress.c b/fs/f2fs/compress.c
>> index 12a56f9e1572..6a65443fd9b3 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;
> 
> Do we need to return EIO right away?
> 			if (!page)

page point is valid here, however page is not uptodate here.

Maybe we can set Pg_error flag if decompress failed, and here, we can break the
loop if Pg_error flag was set?

Thanks,

> 				goto retry;
> 			ret = -EIO;
> 			goto out;
> 
>> +			if (retry_count--)
>> +				goto retry;
>> +			else {
>> +				ret = -EIO;
>> +				goto out;
>> +			}
>>   		}
>>   	}
>>   
>> -- 
>> 2.25.1


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