linux-kernel - Re: [f2fs-dev] [PATCH 2/2] f2fs: report # of free inodes more precisely

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Message-ID: <2b10c6e0-50d2-04f6-f7d2-cfc95f90e8e6@kernel.org>
Date:   Wed, 28 Jun 2017 21:01:40 +0800
From:   Chao Yu <chao@...nel.org>
To:     Jaegeuk Kim <jaegeuk@...nel.org>, Chao Yu <yuchao0@...wei.com>
Cc:     linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-f2fs-devel@...ts.sourceforge.net
Subject: Re: [f2fs-dev] [PATCH 2/2] f2fs: report # of free inodes more
 precisely

On 2017/6/26 22:58, Jaegeuk Kim wrote:
> On 06/26, Chao Yu wrote:
>> Hi Jaegeuk,
>>
>> On 2017/6/25 0:25, Jaegeuk Kim wrote:
>>> If the partition is small, we don't need to report total # of inodes including
>>> hidden free nodes.
>>>
>>> Signed-off-by: Jaegeuk Kim <jaegeuk@...nel.org>
>>> ---
>>>  fs/f2fs/super.c | 14 +++++++++++---
>>>  1 file changed, 11 insertions(+), 3 deletions(-)
>>>
>>> diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
>>> index 8e39b850bfc0..3da6fb276f8b 100644
>>> --- a/fs/f2fs/super.c
>>> +++ b/fs/f2fs/super.c
>>> @@ -680,6 +680,7 @@ static int f2fs_statfs(struct dentry *dentry, struct kstatfs *buf)
>>>  	struct f2fs_sb_info *sbi = F2FS_SB(sb);
>>>  	u64 id = huge_encode_dev(sb->s_bdev->bd_dev);
>>>  	block_t total_count, user_block_count, start_count, ovp_count;
>>> +	u64 avail_node_count;
>>>  
>>>  	total_count = le64_to_cpu(sbi->raw_super->block_count);
>>>  	user_block_count = sbi->user_block_count;
>>> @@ -692,9 +693,16 @@ static int f2fs_statfs(struct dentry *dentry, struct kstatfs *buf)
>>>  	buf->f_bfree = user_block_count - valid_user_blocks(sbi) + ovp_count;
>>>  	buf->f_bavail = user_block_count - valid_user_blocks(sbi);
>>>  
>>> -	buf->f_files = sbi->total_node_count - F2FS_RESERVED_NODE_NUM;
>>> -	buf->f_ffree = min(buf->f_files - valid_node_count(sbi),
>>> -							buf->f_bavail);
>>> +	avail_node_count = sbi->total_node_count - F2FS_RESERVED_NODE_NUM;
>>> +
>>> +	if (avail_node_count > user_block_count) {
>>> +		buf->f_files = user_block_count;
>>> +		buf->f_ffree = buf->f_bavail;
>>
>> f_ffree is limited both by remained free nid count and free block count, so it
>> needs to change like this?
> 
> I thought both of them are same, since node block will consume user block. So,
> we don't need to do min() again.

avail_node_count comes from total free nid counts which is limited with
nid_bitmap size, buf->f_bavail comes from total user block count which
can both cosumed by node and data. So the value of them may not be the same.

Thanks,

> 
>>
>> if (avail_node_count > user_block_count)
>> 	avail_node_count = user_block_count;
>>
>> buf->f_files = avail_node_count;
>> buf->f_ffree = min(avail_node_count - valid_node_count(sbi),
>> 					buf->f_bavail);
>>
>> Thanks,
>>
>>> +	} else {
>>> +		buf->f_files = avail_node_count;
>>> +		buf->f_ffree = min(avail_node_count - valid_node_count(sbi),
>>> +					buf->f_bavail);
>>> +	}
>>>  
>>>  	buf->f_namelen = F2FS_NAME_LEN;
>>>  	buf->f_fsid.val[0] = (u32)id;
>>>
> 
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