linux-kernel - Re: [PATCH v9 06/13] exfat: add exfat entry operations

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Date:   Wed, 8 Jan 2020 19:00:40 +0100
From:   Christoph Hellwig <hch@....de>
To:     Namjae Jeon <namjae.jeon@...sung.com>
Cc:     linux-kernel@...r.kernel.org, linux-fsdevel@...r.kernel.org,
        gregkh@...uxfoundation.org, valdis.kletnieks@...edu, hch@....de,
        sj1557.seo@...sung.com, linkinjeon@...il.com, pali.rohar@...il.com
Subject: Re: [PATCH v9 06/13] exfat: add exfat entry operations

> +int exfat_ent_get(struct super_block *sb, unsigned int loc,
> +		unsigned int *content)
> +{
> +	struct exfat_sb_info *sbi = EXFAT_SB(sb);
> +	int err;
> +
> +	if (!is_valid_cluster(sbi, loc)) {
> +		exfat_fs_error(sb, "invalid access to FAT (entry 0x%08x)",
> +			loc);
> +		return -EIO;
> +	}
> +
> +	err = __exfat_ent_get(sb, loc, content);
> +	if (err) {
> +		exfat_fs_error(sb,
> +			"failed to access to FAT (entry 0x%08x, err:%d)",
> +			loc, err);
> +		return err;
> +	}
> +
> +	if (!is_reserved_cluster(*content) &&
> +			!is_valid_cluster(sbi, *content)) {
> +		exfat_fs_error(sb,
> +			"invalid access to FAT (entry 0x%08x) bogus content (0x%08x)",
> +			loc, *content);
> +		return -EIO;
> +	}
> +
> +	if (*content == EXFAT_FREE_CLUSTER) {
> +		exfat_fs_error(sb,
> +			"invalid access to FAT free cluster (entry 0x%08x)",
> +			loc);
> +		return -EIO;
> +	}
> +
> +	if (*content == EXFAT_BAD_CLUSTER) {
> +		exfat_fs_error(sb,
> +			"invalid access to FAT bad cluster (entry 0x%08x)",
> +			loc);
> +		return -EIO;
> +	}
> +	return 0;

Maybe these explicit checks should move up, and then is_reserved_cluster
can be replaced with an explicit check just for EXFAT_EOF_CLUSTER?

Otherwise looks good:

Reviewed-by: Christoph Hellwig <hch@....de>