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Date:   Thu, 3 Jun 2021 22:10:48 -0700
From:   Eric Biggers <ebiggers@kernel.org>
To:     Jaegeuk Kim <jaegeuk@kernel.org>
Cc:     linux-kernel@vger.kernel.org,
        linux-f2fs-devel@lists.sourceforge.net
Subject: Re: [f2fs-dev] [PATCH v2] f2fs: clean up /sys/fs/f2fs/<disk>/features
Message-ID: <YLm12A7qKFyYYU0Z@sol.localdomain>
References: <20210603220834.1949988-1-jaegeuk@kernel.org>
 <YLmvIH/wVeKwSPCN@google.com>
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On Thu, Jun 03, 2021 at 09:42:08PM -0700, Jaegeuk Kim wrote:
>  enum feat_id {
>  	FEAT_CRYPTO = 0,
>  	FEAT_BLKZONED,
> @@ -587,6 +601,7 @@ enum feat_id {
>  	FEAT_RO,
>  	FEAT_TEST_DUMMY_ENCRYPTION_V2,
>  	FEAT_ENCRYPTED_CASEFOLD,
> +	FEAT_PIN_FILE,
>  };
>  
>  static ssize_t f2fs_feature_show(struct f2fs_attr *a,
> @@ -610,6 +625,7 @@ static ssize_t f2fs_feature_show(struct f2fs_attr *a,
>  	case FEAT_RO:
>  	case FEAT_TEST_DUMMY_ENCRYPTION_V2:
>  	case FEAT_ENCRYPTED_CASEFOLD:
> +	case FEAT_PIN_FILE:
>  		return sprintf(buf, "supported\n");
>  	}
>  	return 0;

There's no need for the feat_id enum to exist.  If f2fs_feature_show() just
always printed "supported\n", it will do the right thing.

Also, adding pin_file probably should be a separate patch.  That seems to be a
bug fix, as pin_file was mistakenly added to the per-sb feature list instead of
to the kernel feature list?

> +static ssize_t f2fs_sb_feature_show(struct f2fs_attr *a,
> +		struct f2fs_sb_info *sbi, char *buf)
> +{
> +	if (F2FS_MATCH_FEATURE(sbi, a->id))
> +		return sprintf(buf, "supported\n");
> +	return sprintf(buf, "unsupported\n");
> +}

This can just use F2FS_HAS_FEATURE(), provided that encrypted_casefold isn't
included here, which it shouldn't be (as discussed elsewhere).

- Eric