Re: [f2fs-dev] [PATCH] f2fs: set zstd default compression level to 3

[Chao Yu]

On 2023/6/8 0:29, Jaegeuk Kim wrote:
> ZSTD does not support compress_level=0.

IIUC, it looks the range is [0, ZSTD_MAX_CLEVEL], 0 equals to default
(ZSTD_CLEVEL_DEFAULT).

zstd_compress.c

    /* row */
    if (compressionLevel == 0) row = ZSTD_CLEVEL_DEFAULT;   /* 0 == default */
    else if (compressionLevel < 0) row = 0;   /* entry 0 is baseline for fast mode */
    else if (compressionLevel > ZSTD_MAX_CLEVEL) row = ZSTD_MAX_CLEVEL;
    else row = compressionLevel;

Thanks,

> The commit d7ffafc99c42 ("f2fs: add sanity compress level check for compressed file")
> revealed the issue.
>
> Signed-off-by: Jaegeuk Kim <jaegeuk@xxxxxxxxxx>
> ---
>   fs/f2fs/super.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
> index 8fd23caa1ed9..1fb8d4f27a40 100644
> --- a/fs/f2fs/super.c
> +++ b/fs/f2fs/super.c
> @@ -627,7 +627,7 @@ static int f2fs_set_zstd_level(struct f2fs_sb_info *sbi, const char *str)
>   	int len = 4;
>   
>   	if (strlen(str) == len) {
> -		F2FS_OPTION(sbi).compress_level = 0;
> +		F2FS_OPTION(sbi).compress_level = 3;
>   		return 0;
>   	}
>