From: Tejun Heo <tj@kernel.org>
To: Tahsin Erdogan <tahsin@google.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>,
linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] writeback: inode cgroup wb switch should skip inode with zero i_count
Date: Mon, 13 Jun 2016 18:11:47 -0400 [thread overview]
Message-ID: <20160613221147.GJ31708@htj.duckdns.org> (raw)
In-Reply-To: <1465441168-17738-1-git-send-email-tahsin@google.com>
On Wed, Jun 08, 2016 at 07:59:28PM -0700, Tahsin Erdogan wrote:
> Asynchronous wb switching of inodes takes an additional ref count on an
> inode to make sure inode remains valid until switchover is completed.
>
> However, it is possible that inode->i_count has already reached zero
> while inode is in writeback queue:
>
> ------------[ cut here ]------------
> WARNING: CPU: 1 PID: 917 at fs/inode.c:397 ihold+0x2b/0x30
> CPU: 1 PID: 917 Comm: kworker/u4:5 Not tainted 4.7.0-rc2+ #49
> Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs
> 01/01/2011
> Workqueue: writeback wb_workfn (flush-8:16)
> 0000000000000000 ffff88007ca0fb58 ffffffff805990af 0000000000000000
> 0000000000000000 ffff88007ca0fb98 ffffffff80268702 0000018d000004e2
> ffff88007cef40e8 ffff88007c9b89a8 ffff880079e3a740 0000000000000003
> Call Trace:
> [<ffffffff805990af>] dump_stack+0x4d/0x6e
> [<ffffffff80268702>] __warn+0xc2/0xe0
> [<ffffffff802687d8>] warn_slowpath_null+0x18/0x20
> [<ffffffff8035b4ab>] ihold+0x2b/0x30
> [<ffffffff80367ecc>] inode_switch_wbs+0x11c/0x180
> [<ffffffff80369110>] wbc_detach_inode+0x170/0x1a0
> [<ffffffff80369abc>] writeback_sb_inodes+0x21c/0x530
> [<ffffffff80369f7e>] wb_writeback+0xee/0x1e0
> [<ffffffff8036a147>] wb_workfn+0xd7/0x280
> [<ffffffff80287531>] ? try_to_wake_up+0x1b1/0x2b0
> [<ffffffff8027bb09>] process_one_work+0x129/0x300
> [<ffffffff8027be06>] worker_thread+0x126/0x480
> [<ffffffff8098cde7>] ? __schedule+0x1c7/0x561
> [<ffffffff8027bce0>] ? process_one_work+0x300/0x300
> [<ffffffff80280ff4>] kthread+0xc4/0xe0
> [<ffffffff80335578>] ? kfree+0xc8/0x100
> [<ffffffff809903cf>] ret_from_fork+0x1f/0x40
> [<ffffffff80280f30>] ? __kthread_parkme+0x70/0x70
> ---[ end trace aaefd2fd9f306bc4 ]---
>
> Signed-off-by: Tahsin Erdogan <tahsin@google.com>
Acked-by: Tejun Heo <tj@kernel.org>
Can you please repost the patch to Jens Axboe <axboe@kernel.dk> with
acked-by added? Please also cc Jan Kara <jack@suse.com>.
Thanks.
--
tejun
next prev parent reply other threads:[~2016-06-13 22:11 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-06-09 2:59 Tahsin Erdogan
2016-06-13 22:11 ` Tejun Heo [this message]
2016-06-13 22:37 Tahsin Erdogan
2016-06-15 12:26 ` Jan Kara
2016-06-15 14:55 ` Tejun Heo
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