Cleanup all block checking places, replace them with helper function
do_check_range().

Signed-off-by: Zhihao Cheng <chengzhihao1@huawei.com>
---
 fs/quota/quota_tree.c | 28 ++++++++++++----------------
 1 file changed, 12 insertions(+), 16 deletions(-)

diff --git a/fs/quota/quota_tree.c b/fs/quota/quota_tree.c
index f89186b6db1d..47711e739ddb 100644
--- a/fs/quota/quota_tree.c
+++ b/fs/quota/quota_tree.c
@@ -71,11 +71,12 @@ static ssize_t write_blk(struct qtree_mem_dqinfo *info, uint blk, char *buf)
 	return ret;
 }
 
-static inline int do_check_range(struct super_block *sb, uint val, uint max_val)
+static inline int do_check_range(struct super_block *sb, uint val,
+				 uint min_val, uint max_val)
 {
-	if (val >= max_val) {
-		quota_error(sb, "Getting block too big (%u >= %u)",
-			    val, max_val);
+	if (val < min_val || val >= max_val) {
+		quota_error(sb, "Getting block %u out of range %u-%u",
+			    val, min_val, max_val);
 		return -EUCLEAN;
 	}
 
@@ -89,11 +90,11 @@ static int check_dquot_block_header(struct qtree_mem_dqinfo *info,
 	uint nextblk, prevblk;
 
 	nextblk = le32_to_cpu(dh->dqdh_next_free);
-	err = do_check_range(info->dqi_sb, nextblk, info->dqi_blocks);
+	err = do_check_range(info->dqi_sb, nextblk, 0, info->dqi_blocks);
 	if (err)
 		return err;
 	prevblk = le32_to_cpu(dh->dqdh_prev_free);
-	err = do_check_range(info->dqi_sb, prevblk, info->dqi_blocks);
+	err = do_check_range(info->dqi_sb, prevblk, 0, info->dqi_blocks);
 	if (err)
 		return err;
 
@@ -518,12 +519,10 @@ static int remove_tree(struct qtree_mem_dqinfo *info, struct dquot *dquot,
 		goto out_buf;
 	}
 	newblk = le32_to_cpu(ref[get_index(info, dquot->dq_id, depth)]);
-	if (newblk < QT_TREEOFF || newblk >= info->dqi_blocks) {
-		quota_error(dquot->dq_sb, "Getting block too big (%u >= %u)",
-			    newblk, info->dqi_blocks);
-		ret = -EUCLEAN;
+	ret = do_check_range(dquot->dq_sb, newblk, QT_TREEOFF,
+			     info->dqi_blocks);
+	if (ret)
 		goto out_buf;
-	}
 
 	if (depth == info->dqi_qtree_depth - 1) {
 		ret = free_dqentry(info, dquot, newblk);
@@ -624,12 +623,9 @@ static loff_t find_tree_dqentry(struct qtree_mem_dqinfo *info,
 	blk = le32_to_cpu(ref[get_index(info, dquot->dq_id, depth)]);
 	if (!blk)	/* No reference? */
 		goto out_buf;
-	if (blk < QT_TREEOFF || blk >= info->dqi_blocks) {
-		quota_error(dquot->dq_sb, "Getting block too big (%u >= %u)",
-			    blk, info->dqi_blocks);
-		ret = -EUCLEAN;
+	ret = do_check_range(dquot->dq_sb, blk, QT_TREEOFF, info->dqi_blocks);
+	if (ret)
 		goto out_buf;
-	}
 
 	if (depth < info->dqi_qtree_depth - 1)
 		ret = find_tree_dqentry(info, dquot, blk, depth+1);
-- 
2.31.1

On Thu 22-09-22 21:04:00, Zhihao Cheng wrote:
> Cleanup all block checking places, replace them with helper function
> do_check_range().
> 
> Signed-off-by: Zhihao Cheng <chengzhihao1@huawei.com>
> ---
>  fs/quota/quota_tree.c | 28 ++++++++++++----------------
>  1 file changed, 12 insertions(+), 16 deletions(-)

Thanks for the fix! One comment below:

> diff --git a/fs/quota/quota_tree.c b/fs/quota/quota_tree.c
> index f89186b6db1d..47711e739ddb 100644
> --- a/fs/quota/quota_tree.c
> +++ b/fs/quota/quota_tree.c
> @@ -71,11 +71,12 @@ static ssize_t write_blk(struct qtree_mem_dqinfo *info, uint blk, char *buf)
>  	return ret;
>  }
>  
> -static inline int do_check_range(struct super_block *sb, uint val, uint max_val)
> +static inline int do_check_range(struct super_block *sb, uint val,
> +				 uint min_val, uint max_val)
>  {
> -	if (val >= max_val) {
> -		quota_error(sb, "Getting block too big (%u >= %u)",
> -			    val, max_val);
> +	if (val < min_val || val >= max_val) {
> +		quota_error(sb, "Getting block %u out of range %u-%u",
> +			    val, min_val, max_val);
>  		return -EUCLEAN;
>  	}

It is strange that do_check_range() checks min_val() with strict inequality
and max_val with non-strict one. That's off-by-one problem waiting to
happen when we forget about this detail. Probably make max_val
non-inclusive as well (the parameter max_val suggests the passed value is
the biggest valid one anyway).

								Honza

-- 
Jan Kara <jack@suse.com>
SUSE Labs, CR

在 2022/9/23 19:48, Jan Kara 写道:
> On Thu 22-09-22 21:04:00, Zhihao Cheng wrote:
>> Cleanup all block checking places, replace them with helper function
>> do_check_range().
>>
>> Signed-off-by: Zhihao Cheng <chengzhihao1@huawei.com>
>> ---
>>   fs/quota/quota_tree.c | 28 ++++++++++++----------------
>>   1 file changed, 12 insertions(+), 16 deletions(-)
> 
> Thanks for the fix! One comment below:
> 
>> diff --git a/fs/quota/quota_tree.c b/fs/quota/quota_tree.c
>> index f89186b6db1d..47711e739ddb 100644
>> --- a/fs/quota/quota_tree.c
>> +++ b/fs/quota/quota_tree.c
>> @@ -71,11 +71,12 @@ static ssize_t write_blk(struct qtree_mem_dqinfo *info, uint blk, char *buf)
>>   	return ret;
>>   }
>>   
>> -static inline int do_check_range(struct super_block *sb, uint val, uint max_val)
>> +static inline int do_check_range(struct super_block *sb, uint val,
>> +				 uint min_val, uint max_val)
>>   {
>> -	if (val >= max_val) {
>> -		quota_error(sb, "Getting block too big (%u >= %u)",
>> -			    val, max_val);
>> +	if (val < min_val || val >= max_val) {
>> +		quota_error(sb, "Getting block %u out of range %u-%u",
>> +			    val, min_val, max_val);
>>   		return -EUCLEAN;
>>   	}
> 
> It is strange that do_check_range() checks min_val() with strict inequality
> and max_val with non-strict one. That's off-by-one problem waiting to
> happen when we forget about this detail. Probably make max_val
> non-inclusive as well (the parameter max_val suggests the passed value is
> the biggest valid one anyway).
> 
> 								Honza
> 

I have sent v3 series, see
https://lore.kernel.org/all/20220923134555.2623931-1-chengzhihao1@huawei.com/T/