linux-kernel - Re: [PATCH] zonefs: fix to update .i_wr_refcnt correctly in zonefs_open

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Message-ID: <64952e0e-0bd8-cbb2-9400-b4c16a886eee@huawei.com>
Date:   Wed, 17 Mar 2021 08:56:14 +0800
From:   Chao Yu <yuchao0@...wei.com>
To:     Damien Le Moal <Damien.LeMoal@....com>,
        Naohiro Aota <Naohiro.Aota@....com>,
        "jth@...nel.org" <jth@...nel.org>
CC:     "linux-fsdevel@...r.kernel.org" <linux-fsdevel@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "chao@...nel.org" <chao@...nel.org>
Subject: Re: [PATCH] zonefs: fix to update .i_wr_refcnt correctly in
 zonefs_open_zone()

On 2021/3/17 7:30, Damien Le Moal wrote:
> On 2021/03/16 21:30, Chao Yu wrote:
>> In zonefs_open_zone(), if opened zone count is larger than
>> .s_max_open_zones threshold, we missed to recover .i_wr_refcnt,
>> fix this.
>>
>> Fixes: b5c00e975779 ("zonefs: open/close zone on file open/close")
>> Signed-off-by: Chao Yu <yuchao0@...wei.com>
>> ---
>>   fs/zonefs/super.c | 6 +++---
>>   1 file changed, 3 insertions(+), 3 deletions(-)
>>
>> diff --git a/fs/zonefs/super.c b/fs/zonefs/super.c
>> index 0fe76f376dee..be6b99f7de74 100644
>> --- a/fs/zonefs/super.c
>> +++ b/fs/zonefs/super.c
>> @@ -966,8 +966,7 @@ static int zonefs_open_zone(struct inode *inode)
>>   
>>   	mutex_lock(&zi->i_truncate_mutex);
>>   
>> -	zi->i_wr_refcnt++;
>> -	if (zi->i_wr_refcnt == 1) {
>> +	if (zi->i_wr_refcnt == 0) {
> 
> Nit: if (!zi->i_wr_refcnt) ? I can change that when applying.

More clean, thanks. :)

Thanks,

> 
>>   
>>   		if (atomic_inc_return(&sbi->s_open_zones) > sbi->s_max_open_zones) {
>>   			atomic_dec(&sbi->s_open_zones);
>> @@ -978,7 +977,6 @@ static int zonefs_open_zone(struct inode *inode)
>>   		if (i_size_read(inode) < zi->i_max_size) {
>>   			ret = zonefs_zone_mgmt(inode, REQ_OP_ZONE_OPEN);
>>   			if (ret) {
>> -				zi->i_wr_refcnt--;
>>   				atomic_dec(&sbi->s_open_zones);
>>   				goto unlock;
>>   			}
>> @@ -986,6 +984,8 @@ static int zonefs_open_zone(struct inode *inode)
>>   		}
>>   	}
>>   
>> +	zi->i_wr_refcnt++;
>> +
>>   unlock:
>>   	mutex_unlock(&zi->i_truncate_mutex);
>>   
>>
> 
> Good catch ! Will apply this and check zonefs test suite as this bug went
> undetected.
> 
> Thanks.
>