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From: Al Viro <viro@zeniv.linux.org.uk>
To: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Cc: Nitesh Shetty <nj.shetty@samsung.com>,
	axboe@kernel.dk, agk@redhat.com, snitzer@kernel.org,
	dm-devel@redhat.com, kbusch@kernel.org, hch@lst.de,
	sagi@grimberg.me, james.smart@broadcom.com, kch@nvidia.com,
	naohiro.aota@wdc.com, jth@kernel.org,
	linux-block@vger.kernel.org, linux-kernel@vger.kernel.org,
	linux-nvme@lists.infradead.org, linux-fsdevel@vger.kernel.org,
	anuj20.g@samsung.com, joshi.k@samsung.com, p.raghav@samsung.com,
	nitheshshetty@gmail.com, gost.dev@samsung.com
Subject: Re: [PATCH v5 10/10] fs: add support for copy file range in zonefs
Date: Fri, 25 Nov 2022 04:18:16 +0000	[thread overview]
Message-ID: <Y4BCCB9U10mkiehu@ZenIV> (raw)
In-Reply-To: <349a4d66-3a9f-a095-005c-1f180c5f3aac@opensource.wdc.com>

On Thu, Nov 24, 2022 at 10:47:55AM +0900, Damien Le Moal wrote:
> >> +	inode_lock(src_inode);
> >> +	inode_lock(dst_inode);
> > 
> > So you did zonefs_copy_file_checks() outside of these locks, which mean
> > that everything about the source and destination files may have changed.
> > This does not work.
> 
> I forgot to mention that locking 2 inodes blindly like this can leads to
> deadlocks if another process tries a copy range from dst to src at the
> same time (lock order is reversed and so can deadlock).

Not to mention the deadlocks with existing places where fs/namei.c locks
two inodes...

  reply	other threads:[~2022-11-25  4:18 UTC|newest]

Thread overview: 33+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <CGME20221123061010epcas5p21cef9d23e4362b01f2b19d1117e1cdf5@epcas5p2.samsung.com>
2022-11-23  5:58 ` [PATCH v5 00/10] Implement copy offload support Nitesh Shetty
2022-11-23  5:58   ` [PATCH v5 01/10] block: Introduce queue limits for copy-offload support Nitesh Shetty
2022-11-23  5:58   ` [PATCH v5 02/10] block: Add copy offload support infrastructure Nitesh Shetty
2022-11-23  8:04     ` Ming Lei
2022-11-23 10:07       ` Nitesh Shetty
2022-11-24  0:03         ` Ming Lei
2022-11-29 11:44           ` Nitesh Shetty
2022-12-07  5:54             ` Nitesh Shetty
2022-12-07 11:19               ` Ming Lei
2022-12-09  8:16                 ` Nitesh Shetty
2022-11-23  5:58   ` [PATCH v5 03/10] block: add emulation for copy Nitesh Shetty
2022-11-23  5:58   ` [PATCH v5 04/10] block: Introduce a new ioctl " Nitesh Shetty
2022-11-23  5:58   ` [PATCH v5 05/10] nvme: add copy offload support Nitesh Shetty
2022-11-23  5:58   ` [PATCH v5 06/10] nvmet: add copy command support for bdev and file ns Nitesh Shetty
     [not found]     ` <482586a3-f45d-a17b-7630-341fb0e1ee96@linux.alibaba.com>
2022-11-23  9:39       ` Nitesh Shetty
2022-12-06  9:22     ` kernel test robot
2022-11-23  5:58   ` [PATCH v5 07/10] dm: Add support for copy offload Nitesh Shetty
2022-11-23  5:58   ` [PATCH v5 08/10] dm: Enable copy offload for dm-linear target Nitesh Shetty
2022-11-23  5:58   ` [PATCH v5 09/10] dm kcopyd: use copy offload support Nitesh Shetty
2022-11-23  5:58   ` [PATCH v5 10/10] fs: add support for copy file range in zonefs Nitesh Shetty
2022-11-23  6:53     ` Amir Goldstein
2022-11-23 10:13       ` Nitesh Shetty
2022-11-24  1:32     ` Damien Le Moal
2022-11-24  1:47       ` Damien Le Moal
2022-11-25  4:18         ` Al Viro [this message]
2022-11-29 12:22         ` Nitesh Shetty
2022-11-29 23:45           ` Damien Le Moal
2022-11-30  4:17             ` Nitesh Shetty
2022-11-30  9:55               ` Damien Le Moal
2022-11-23 22:56   ` [PATCH v5 00/10] Implement copy offload support Chaitanya Kulkarni
2022-11-29 12:16     ` Nitesh Shetty
2022-11-30  0:05       ` Chaitanya Kulkarni
2022-11-30  4:14         ` Nitesh Shetty

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