linux-kernel - Re: [PATCH v2] fs/dcache.c: avoid soft-lockup in dput()

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Date:   Fri, 16 Sep 2016 18:20:53 +0530
From:   Vaishali Thakkar <vaishali.thakkar@...cle.com>
To:     Al Viro <viro@...IV.linux.org.uk>
Cc:     Wei Fang <fangwei1@...wei.com>, linux-fsdevel@...r.kernel.org,
        akpm@...ux-foundation.org, jack@...e.com, axboe@...nel.dk,
        tj@...nel.org, linux-kernel@...r.kernel.org, stable@...r.kernel.org
Subject: Re: [PATCH v2] fs/dcache.c: avoid soft-lockup in dput()



On Friday 16 September 2016 05:40 PM, Al Viro wrote:
> On Fri, Sep 16, 2016 at 01:19:19PM +0530, Vaishali Thakkar wrote:
> 
>> Hi,
>>
>> Just a question regarding this change. As after this change
>> dput() is sleepable, is it still safe to use if under the
>> spinlock in the function d_prune_aliases?
> 
> It has always been sleepable and it wouldn't have been safe to use
> under spinlocks.  Which d_prune_aliases() does not do - __dentry_kill()
> is called with dentry, its parent and its inode (if present) all locked and
> it drops all those locks before returning.

Ah, I see. Alright. Thanks for the clarification.

> 

-- 
Vaishali