linux-kernel - Re: [PATCH v3 2/4] ext4: add helper to check quota inums

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Message-ID: <20221026093818.cxnyr6h5ioxukgvf@quack3>
Date:   Wed, 26 Oct 2022 11:38:18 +0200
From:   Jan Kara <jack@...e.cz>
To:     Baokun Li <libaokun1@...wei.com>
Cc:     linux-ext4@...r.kernel.org, tytso@....edu,
        adilger.kernel@...ger.ca, jack@...e.cz, ritesh.list@...il.com,
        linux-kernel@...r.kernel.org, yi.zhang@...wei.com,
        yukuai3@...wei.com
Subject: Re: [PATCH v3 2/4] ext4: add helper to check quota inums

On Wed 26-10-22 12:23:08, Baokun Li wrote:
> Before quota is enabled, a check on the preset quota inums in
> ext4_super_block is added to prevent wrong quota inodes from being loaded.
> In addition, when the quota fails to be enabled, the quota type and quota
> inum are printed to facilitate fault locating.
> 
> Signed-off-by: Baokun Li <libaokun1@...wei.com>

Makes sense. Feel free to add:

Reviewed-by: Jan Kara <jack@...e.cz>

								Honza

> ---
>  fs/ext4/super.c | 28 +++++++++++++++++++++++++---
>  1 file changed, 25 insertions(+), 3 deletions(-)
> 
> diff --git a/fs/ext4/super.c b/fs/ext4/super.c
> index 34b78f380968..0b4060d52d63 100644
> --- a/fs/ext4/super.c
> +++ b/fs/ext4/super.c
> @@ -6885,6 +6885,20 @@ static int ext4_quota_on(struct super_block *sb, int type, int format_id,
>  	return err;
>  }
>  
> +static inline bool ext4_check_quota_inum(int type, unsigned long qf_inum)
> +{
> +	switch (type) {
> +	case USRQUOTA:
> +		return qf_inum == EXT4_USR_QUOTA_INO;
> +	case GRPQUOTA:
> +		return qf_inum == EXT4_GRP_QUOTA_INO;
> +	case PRJQUOTA:
> +		return qf_inum >= EXT4_GOOD_OLD_FIRST_INO;
> +	default:
> +		BUG();
> +	}
> +}
> +
>  static int ext4_quota_enable(struct super_block *sb, int type, int format_id,
>  			     unsigned int flags)
>  {
> @@ -6901,9 +6915,16 @@ static int ext4_quota_enable(struct super_block *sb, int type, int format_id,
>  	if (!qf_inums[type])
>  		return -EPERM;
>  
> +	if (!ext4_check_quota_inum(type, qf_inums[type])) {
> +		ext4_error(sb, "Bad quota inum: %lu, type: %d",
> +				qf_inums[type], type);
> +		return -EUCLEAN;
> +	}
> +
>  	qf_inode = ext4_iget(sb, qf_inums[type], EXT4_IGET_SPECIAL);
>  	if (IS_ERR(qf_inode)) {
> -		ext4_error(sb, "Bad quota inode # %lu", qf_inums[type]);
> +		ext4_error(sb, "Bad quota inode: %lu, type: %d",
> +				qf_inums[type], type);
>  		return PTR_ERR(qf_inode);
>  	}
>  
> @@ -6942,8 +6963,9 @@ int ext4_enable_quotas(struct super_block *sb)
>  			if (err) {
>  				ext4_warning(sb,
>  					"Failed to enable quota tracking "
> -					"(type=%d, err=%d). Please run "
> -					"e2fsck to fix.", type, err);
> +					"(type=%d, err=%d, ino=%lu). "
> +					"Please run e2fsck to fix.", type,
> +					err, qf_inums[type]);
>  				for (type--; type >= 0; type--) {
>  					struct inode *inode;
>  
> -- 
> 2.31.1
> 
-- 
Jan Kara <jack@...e.com>
SUSE Labs, CR