linux-kernel - Re: [PATCH v2 1/2] f2fs: introduce get_available_block

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Date:   Tue, 3 Sep 2019 07:29:49 +0800
From:   Chao Yu <chao@...nel.org>
To:     Jaegeuk Kim <jaegeuk@...nel.org>, Chao Yu <yuchao0@...wei.com>
Cc:     linux-f2fs-devel@...ts.sourceforge.net,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2 1/2] f2fs: introduce get_available_block_count() for
 cleanup

On 2019-9-3 6:54, Jaegeuk Kim wrote:
> On 08/31, Chao Yu wrote:
>> There are very similar codes in inc_valid_block_count() and
>> inc_valid_node_count() which is used for available user block
>> count calculation.
>>
>> This patch introduces a new helper get_available_block_count()
>> to include those common codes, and used it instead for cleanup.
>>
>> Signed-off-by: Chao Yu <yuchao0@...wei.com>
>> ---
>> v2:
>> - fix panic during recovery
>>  fs/f2fs/f2fs.h | 47 +++++++++++++++++++++++++++--------------------
>>  1 file changed, 27 insertions(+), 20 deletions(-)
>>
>> diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
>> index a89ad8cab821..9c010e6cba5c 100644
>> --- a/fs/f2fs/f2fs.h
>> +++ b/fs/f2fs/f2fs.h
>> @@ -1756,6 +1756,27 @@ static inline bool __allow_reserved_blocks(struct f2fs_sb_info *sbi,
>>  	return false;
>>  }
>>  
>> +static inline unsigned int get_available_block_count(struct f2fs_sb_info *sbi,
>> +						struct inode *inode, bool cap)
>> +{
>> +	block_t avail_user_block_count;
>> +
>> +	avail_user_block_count = sbi->user_block_count -
>> +					sbi->current_reserved_blocks;
>> +
>> +	if (!__allow_reserved_blocks(sbi, inode, cap))
>> +		avail_user_block_count -= F2FS_OPTION(sbi).root_reserved_blocks;
>> +
>> +	if (unlikely(is_sbi_flag_set(sbi, SBI_CP_DISABLED))) {
>> +		if (avail_user_block_count > sbi->unusable_block_count)
>> +			avail_user_block_count -= sbi->unusable_block_count;
>> +		else
>> +			avail_user_block_count = 0;
>> +	}
>> +
>> +	return avail_user_block_count;
>> +}
>> +
>>  static inline void f2fs_i_blocks_write(struct inode *, block_t, bool, bool);
>>  static inline int inc_valid_block_count(struct f2fs_sb_info *sbi,
>>  				 struct inode *inode, blkcnt_t *count)
>> @@ -1782,17 +1803,8 @@ static inline int inc_valid_block_count(struct f2fs_sb_info *sbi,
>>  
>>  	spin_lock(&sbi->stat_lock);
>>  	sbi->total_valid_block_count += (block_t)(*count);
>> -	avail_user_block_count = sbi->user_block_count -
>> -					sbi->current_reserved_blocks;
>> +	avail_user_block_count = get_available_block_count(sbi, inode, true);
>>  
>> -	if (!__allow_reserved_blocks(sbi, inode, true))
>> -		avail_user_block_count -= F2FS_OPTION(sbi).root_reserved_blocks;
>> -	if (unlikely(is_sbi_flag_set(sbi, SBI_CP_DISABLED))) {
>> -		if (avail_user_block_count > sbi->unusable_block_count)
>> -			avail_user_block_count -= sbi->unusable_block_count;
>> -		else
>> -			avail_user_block_count = 0;
>> -	}
>>  	if (unlikely(sbi->total_valid_block_count > avail_user_block_count)) {
>>  		diff = sbi->total_valid_block_count - avail_user_block_count;
>>  		if (diff > *count)
>> @@ -2005,7 +2017,8 @@ static inline int inc_valid_node_count(struct f2fs_sb_info *sbi,
>>  					struct inode *inode, bool is_inode)
>>  {
>>  	block_t	valid_block_count;
>> -	unsigned int valid_node_count, user_block_count;
>> +	unsigned int valid_node_count;
>> +	unsigned int avail_user_block_count;
>>  	int err;
>>  
>>  	if (is_inode) {
>> @@ -2027,16 +2040,10 @@ static inline int inc_valid_node_count(struct f2fs_sb_info *sbi,
>>  
>>  	spin_lock(&sbi->stat_lock);
>>  
>> -	valid_block_count = sbi->total_valid_block_count +
>> -					sbi->current_reserved_blocks + 1;
>> -
>> -	if (!__allow_reserved_blocks(sbi, inode, false))
>> -		valid_block_count += F2FS_OPTION(sbi).root_reserved_blocks;
>> -	user_block_count = sbi->user_block_count;
>> -	if (unlikely(is_sbi_flag_set(sbi, SBI_CP_DISABLED)))
>> -		user_block_count -= sbi->unusable_block_count;
>> +	valid_block_count = sbi->total_valid_block_count + 1;
>> +	avail_user_block_count = get_available_block_count(sbi, inode, false);
> 
> This doesn't look like same?

Actually, calculations of block count in inc_valid_node_count() and
inc_valid_block_count() should be the same, I've no idea why we use different
policy for reserved block for root user.

Thanks,

> 
>>  
>> -	if (unlikely(valid_block_count > user_block_count)) {
>> +	if (unlikely(valid_block_count > avail_user_block_count)) {
>>  		spin_unlock(&sbi->stat_lock);
>>  		goto enospc;
>>  	}
>> -- 
>> 2.18.0.rc1