[PATCH v2 4/7] erofs-utils: mkfs: optionally print warning in erofs_compressor_init

[Gao Xiang]

On 2024/2/20 15:55, Yifan Zhao wrote:
> In the incoming multi-threaded compression support, compressor may be
> initialized more than once in different worker threads, resulting in
> noisy warning output. This patch make sure that each warning message is
> printed only once by adding a print_warning option to the
> erofs_compressor_init() interface.
> 
> Signed-off-by: Yifan Zhao <zhaoyifan at sjtu.edu.cn>
> ---
>   lib/compress.c              | 3 ++-
>   lib/compressor.c            | 5 +++--
>   lib/compressor.h            | 5 +++--
>   lib/compressor_deflate.c    | 4 +++-
>   lib/compressor_libdeflate.c | 4 +++-
>   lib/compressor_liblzma.c    | 5 ++++-
>   lib/compressor_lz4.c        | 2 +-
>   lib/compressor_lz4hc.c      | 2 +-
>   8 files changed, 20 insertions(+), 10 deletions(-)
> 
> diff --git a/lib/compress.c b/lib/compress.c
> index 9611102..41cb6e5 100644
> --- a/lib/compress.c
> +++ b/lib/compress.c
> @@ -1213,7 +1213,8 @@ int z_erofs_compress_init(struct erofs_sb_info *sbi, struct erofs_buffer_head *s
>   
>   		ret = erofs_compressor_init(sbi, c, cfg.c_compr_opts[i].alg,
>   					    cfg.c_compr_opts[i].level,
> -					    cfg.c_compr_opts[i].dict_size);
> +					    cfg.c_compr_opts[i].dict_size,
> +					    true);
>   		if (ret)
>   			return ret;
>   
> diff --git a/lib/compressor.c b/lib/compressor.c
> index 4720e72..9b3794b 100644
> --- a/lib/compressor.c
> +++ b/lib/compressor.c
> @@ -78,7 +78,8 @@ int erofs_compress_destsize(const struct erofs_compress *c,
>   }
>   
>   int erofs_compressor_init(struct erofs_sb_info *sbi, struct erofs_compress *c,
> -			  char *alg_name, int compression_level, u32 dict_size)
> +			  char *alg_name, int compression_level, u32 dict_size,
> +			  bool print_warning)

No need add another variable just for this.

>   {
>   	int ret, i;
>   
> @@ -126,7 +127,7 @@ int erofs_compressor_init(struct erofs_sb_info *sbi, struct erofs_compress *c,
>   			return -EINVAL;
>   		}
>   
> -		ret = erofs_algs[i].c->init(c);
> +		ret = erofs_algs[i].c->init(c, print_warning);
>   		if (ret)
>   			return ret;
>   
> diff --git a/lib/compressor.h b/lib/compressor.h
> index d8ccf2e..522fde0 100644
> --- a/lib/compressor.h
> +++ b/lib/compressor.h
> @@ -17,7 +17,7 @@ struct erofs_compressor {
>   	u32 default_dictsize;
>   	u32 max_dictsize;
>   
> -	int (*init)(struct erofs_compress *c);
> +	int (*init)(struct erofs_compress *c, bool print_warning);
>   	int (*exit)(struct erofs_compress *c);
>   	int (*setlevel)(struct erofs_compress *c, int compression_level);
>   	int (*setdictsize)(struct erofs_compress *c, u32 dict_size);
> @@ -60,7 +60,8 @@ int erofs_compress_destsize(const struct erofs_compress *c,
>   			    void *dst, unsigned int dstsize);
>   
>   int erofs_compressor_init(struct erofs_sb_info *sbi, struct erofs_compress *c,
> -			  char *alg_name, int compression_level, u32 dict_size);
> +			  char *alg_name, int compression_level, u32 dict_size,
> +			  bool print_warning);
>   int erofs_compressor_exit(struct erofs_compress *c);
>   
>   #endif
> diff --git a/lib/compressor_deflate.c b/lib/compressor_deflate.c
> index 8629415..9fe067f 100644
> --- a/lib/compressor_deflate.c
> +++ b/lib/compressor_deflate.c
> @@ -34,7 +34,7 @@ static int compressor_deflate_exit(struct erofs_compress *c)
>   	return 0;
>   }
>   
> -static int compressor_deflate_init(struct erofs_compress *c)
> +static int compressor_deflate_init(struct erofs_compress *c, bool print_warning)
>   {

I'd suggest just use a static atomic variable "workers" here, see:

https://gcc.gnu.org/onlinedocs/gcc/_005f_005fatomic-Builtins.html

>   	if (c->private_data) {
>   		kite_deflate_end(c->private_data);
> @@ -44,9 +44,11 @@ static int compressor_deflate_init(struct erofs_compress *c)
>   	if (IS_ERR_VALUE(c->private_data))
>   		return PTR_ERR(c->private_data);
>   
> +	if (print_warning) {

and if (__atomic_add_fetch(1) == 1), print warning:

>   		erofs_warn("EXPERIMENTAL DEFLATE algorithm in use. Use at your own risk!");
>   		erofs_warn("*Carefully* check filesystem data correctness to avoid corruption!");
>   		erofs_warn("Please send a report to <linux-erofs at lists.ozlabs.org> if something is wrong.");
> +	}
>   	return 0;
>   }
>   
> diff --git a/lib/compressor_libdeflate.c b/lib/compressor_libdeflate.c
> index 62d93f7..0583868 100644
> --- a/lib/compressor_libdeflate.c
> +++ b/lib/compressor_libdeflate.c
> @@ -80,13 +80,15 @@ static int compressor_libdeflate_exit(struct erofs_compress *c)
>   	return 0;
>   }
>   
> -static int compressor_libdeflate_init(struct erofs_compress *c)
> +static int compressor_libdeflate_init(struct erofs_compress *c,
> +				      bool print_warning)
>   {
>   	libdeflate_free_compressor(c->private_data);
>   	c->private_data = libdeflate_alloc_compressor(c->compression_level);
>   	if (!c->private_data)
>   		return -ENOMEM;
>   
> +	if (print_warning)

same here.

>   		erofs_warn("EXPERIMENTAL libdeflate compressor in use. Use at your own risk!");
>   	return 0;
>   }
> diff --git a/lib/compressor_liblzma.c b/lib/compressor_liblzma.c
> index 7183b0b..b048e57 100644
> --- a/lib/compressor_liblzma.c
> +++ b/lib/compressor_liblzma.c
> @@ -81,7 +81,8 @@ static int erofs_compressor_liblzma_setdictsize(struct erofs_compress *c,
>   	return 0;
>   }
>   
> -static int erofs_compressor_liblzma_init(struct erofs_compress *c)
> +static int erofs_compressor_liblzma_init(struct erofs_compress *c,
> +					 bool print_warning)
>   {
>   	struct erofs_liblzma_context *ctx;
>   	u32 preset;
> @@ -103,8 +104,10 @@ static int erofs_compressor_liblzma_init(struct erofs_compress *c)
>   	ctx->opt.dict_size = c->dict_size;
>   
>   	c->private_data = ctx;
> +	if (print_warning) {

same here.

Thanks,
Gao Xiang

>   		erofs_warn("EXPERIMENTAL MicroLZMA feature in use. Use at your own risk!");
>   		erofs_warn("Note that it may take more time since the compressor is still single-threaded for now.");
> +	}
>   	return 0;
>   }
>   
> diff --git a/lib/compressor_lz4.c b/lib/compressor_lz4.c
> index f4e72c3..6aed213 100644
> --- a/lib/compressor_lz4.c
> +++ b/lib/compressor_lz4.c
> @@ -30,7 +30,7 @@ static int compressor_lz4_exit(struct erofs_compress *c)
>   	return 0;
>   }
>   
> -static int compressor_lz4_init(struct erofs_compress *c)
> +static int compressor_lz4_init(struct erofs_compress *c, bool print_warning)
>   {
>   	c->sbi->lz4_max_distance = LZ4_DISTANCE_MAX;
>   	return 0;
> diff --git a/lib/compressor_lz4hc.c b/lib/compressor_lz4hc.c
> index 6fc8847..3d10aa8 100644
> --- a/lib/compressor_lz4hc.c
> +++ b/lib/compressor_lz4hc.c
> @@ -37,7 +37,7 @@ static int compressor_lz4hc_exit(struct erofs_compress *c)
>   	return 0;
>   }
>   
> -static int compressor_lz4hc_init(struct erofs_compress *c)
> +static int compressor_lz4hc_init(struct erofs_compress *c, bool print_warning)
>   {
>   	c->private_data = LZ4_createStreamHC();
>   	if (!c->private_data)