Received-SPF: pass (google.com: domain of linux-ext4-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
Date:   Thu, 24 Sep 2020 10:58:23 -0400
From:   "Theodore Y. Ts'o" <tytso@mit.edu>
To:     Ye Bin <yebin10@huawei.com>
Cc:     riteshh@linux.ibm.com, jack@suse.cz, adilger.kernel@dilger.ca,
        jack@suse.com, linux-ext4@vger.kernel.org
Subject: Re: [PATCH v5 1/2] ext4: Discard preallocations before releasing
 group lock
Message-ID: <20200924145823.GF482521@mit.edu>
References: <20200916113859.1556397-1-yebin10@huawei.com>
 <20200916113859.1556397-2-yebin10@huawei.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <20200916113859.1556397-2-yebin10@huawei.com>
Precedence: bulk

On Wed, Sep 16, 2020 at 07:38:58PM +0800, Ye Bin wrote:
> From: Jan Kara <jack@suse.cz>
> 
> ext4_mb_discard_group_preallocations() can be releasing group lock with
> preallocations accumulated on its local list. Thus although
> discard_pa_seq was incremented and concurrent allocating processes will
> be retrying allocations, it can happen that premature ENOSPC error is
> returned because blocks used for preallocations are not available for
> reuse yet. Make sure we always free locally accumulated preallocations
> before releasing group lock.
> 
> Fixes: 07b5b8e1ac40 ("ext4: mballoc: introduce pcpu seqcnt for freeing PA to improve ENOSPC handling")
> Signed-off-by: Jan Kara <jack@suse.cz>
> Signed-off-by: Ye Bin <yebin10@huawei.com>
> Reviewed-by: Ritesh Harjani <riteshh@linux.ibm.com>

Thanks, applied.

					- Ted