linux-kernel - Re: [PATCH] dcache: unlock inode->i_lock before goto restart tag in, d_prune

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Message-ID: <e71e65a1-ab70-3ff0-6277-8d7d4db4dfc2@huawei.com>
Date:   Thu, 16 Apr 2020 09:52:36 +0800
From:   Zhiqiang Liu <liuzhiqiang26@...wei.com>
To:     Eric Biggers <ebiggers@...nel.org>
CC:     <viro@...iv.linux.org.uk>, <linux-fsdevel@...r.kernel.org>,
        <linux-kernel@...r.kernel.org>, <npiggin@...nel.dk>,
        <zyan@...hat.com>, <hartleys@...ionengravers.com>,
        Yanxiaodan <yanxiaodan@...wei.com>,
        Mingfangsen <mingfangsen@...wei.com>,
        "wubo (T)" <wubo40@...wei.com>
Subject: Re: [PATCH] dcache: unlock inode->i_lock before goto restart tag in,
 d_prune_aliases

On 2020/4/16 9:46, Eric Biggers wrote:
> On Wed, Apr 15, 2020 at 09:20:33PM +0800, Zhiqiang Liu wrote:
>> From: Zhiqiang Liu <liuzhiqiang26@...wei.com>
>>
>> coccicheck reports:
>>   fs/dcache.c:1027:1-10: second lock on line 1027
>>
>> In d_prune_aliases, before goto restart we should unlock
>> inode->i_lock.
>>
>> Fixes: 29355c3904e ("d_prune_alias(): just lock the parent and call __dentry_kill()")
>> Signed-off-by: Zhiqiang Liu <liuzhiqiang26@...wei.com>
>> Signed-off-by: Feilong Lin <linfeilong@...wei.com>
>> ---
>>  fs/dcache.c | 1 +
>>  1 file changed, 1 insertion(+)
>>
>> diff --git a/fs/dcache.c b/fs/dcache.c
>> index b280e07e162b..1532ebe9d9ca 100644
>> --- a/fs/dcache.c
>> +++ b/fs/dcache.c
>> @@ -1030,6 +1030,7 @@ void d_prune_aliases(struct inode *inode)
>>  		if (!dentry->d_lockref.count) {
>>  			struct dentry *parent = lock_parent(dentry);
>>  			if (likely(!dentry->d_lockref.count)) {
>> +				spin_unlock(&inode->i_lock);
>>  				__dentry_kill(dentry);
>>  				dput(parent);
>>  				goto restart;
>> -- 
> 
> Doesn't __dentry_kill() already do the unlock, via dentry_unlink_inode()?
> 
> - Eric
> 
Yes, you are right. Sorry for that. Please ignore this patch.
> .
>