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From:   Paulo Alcantara <pc@cjr.nz>
To:     ChenXiaoSong <chenxiaosong2@huawei.com>, sfrench@samba.org,
        dhowells@redhat.com
Cc:     linux-cifs@vger.kernel.org, samba-technical@lists.samba.org,
        linux-kernel@vger.kernel.org, chenxiaosong2@huawei.com,
        yi.zhang@huawei.com, zhangxiaoxu5@huawei.com, yanaijie@huawei.com
Subject: Re: [PATCH] cifs: fix missing unlock in cifs_file_copychunk_range()
In-Reply-To: <20221119045159.1400244-1-chenxiaosong2@huawei.com>
References: <20221119045159.1400244-1-chenxiaosong2@huawei.com>
Date:   Mon, 21 Nov 2022 11:42:01 -0300
Message-ID: <871qpw1i9y.fsf@cjr.nz>
MIME-Version: 1.0
Content-Type: text/plain
Precedence: bulk

ChenXiaoSong <chenxiaosong2@huawei.com> writes:

> xfstests generic/013 and generic/476 reported WARNING as follows:
>
>   WARNING: lock held when returning to user space!
>   6.1.0-rc5+ #4 Not tainted
>   ------------------------------------------------
>   fsstress/504233 is leaving the kernel with locks still held!
>   2 locks held by fsstress/504233:
>    #0: ffff888054c38850 (&sb->s_type->i_mutex_key#21){+.+.}-{3:3}, at:
>                         lock_two_nondirectories+0xcf/0xf0
>    #1: ffff8880b8fec750 (&sb->s_type->i_mutex_key#21/4){+.+.}-{3:3}, at:
>                         lock_two_nondirectories+0xb7/0xf0
>
> This will lead to deadlock and hungtask.
>
> Fix this by releasing locks when failed to write out on a file range in
> cifs_file_copychunk_range().
>
> Fixes: 3e3761f1ec7d ("smb3: use filemap_write_and_wait_range instead of filemap_write_and_wait")
> Signed-off-by: ChenXiaoSong <chenxiaosong2@huawei.com>
> ---
>  fs/cifs/cifsfs.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)

Reviewed-by: Paulo Alcantara (SUSE) <pc@cjr.nz>