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From: "Theodore Y. Ts'o" <tytso@mit.edu>
To: Christoph Hellwig <hch@lst.de>
Cc: linux-xfs@vger.kernel.org, linux-fsdevel@vger.kernel.org,
	Waiman Long <longman@redhat.com>,
	Peter Zijlstra <peterz@infradead.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>, Will Deacon <will@kernel.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	linux-ext4@vger.kernel.org, cluster-devel@redhat.com,
	linux-kernel@vger.kernel.org, linux-mm@kvack.org
Subject: Re: [PATCH 08/12] ext4: hold i_rwsem until AIO completes
Date: Tue, 14 Jan 2020 16:50:23 -0500	[thread overview]
Message-ID: <20200114215023.GH140865@mit.edu> (raw)
In-Reply-To: <20200114161225.309792-9-hch@lst.de>

On Tue, Jan 14, 2020 at 05:12:21PM +0100, Christoph Hellwig wrote:
> diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
> index 0e8708b77da6..b6aa2d249b30 100644
> --- a/fs/ext4/extents.c
> +++ b/fs/ext4/extents.c
> @@ -4777,9 +4777,6 @@ static long ext4_zero_range(struct file *file, loff_t offset,
>  	if (mode & FALLOC_FL_KEEP_SIZE)
>  		flags |= EXT4_GET_BLOCKS_KEEP_SIZE;
>  
> -	/* Wait all existing dio workers, newcomers will block on i_mutex */
> -	inode_dio_wait(inode);
> -
>  	/* Preallocate the range including the unaligned edges */
>  	if (partial_begin || partial_end) {
>  		ret = ext4_alloc_file_blocks(file,

I note that you've dropped the inode_dio_wait() in ext4's ZERO_RANGE,
COLLAPSE_RANGE, INSERT_RANGE, etc.  We had added these to avoid
problems when various fallocate operations which modify the inode's
logical->physical block mapping racing with direct I/O (both reads or
writes).

I don't see a replacement protection in this patch series.  How does
are file systems supported to protect against such races?

    	 	 	      	      	      - Ted

  reply	other threads:[~2020-01-14 21:51 UTC|newest]

Thread overview: 39+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-01-14 16:12 RFC: hold i_rwsem until aio completes Christoph Hellwig
2020-01-14 16:12 ` [PATCH 01/12] mm: fix a comment in sys_swapon Christoph Hellwig
2020-02-10 23:29   ` Andrew Morton
2020-02-12  7:37     ` Christoph Hellwig
2020-01-14 16:12 ` [PATCH 02/12] locking/rwsem: Exit early when held by an anonymous owner Christoph Hellwig
2020-01-14 18:17   ` Waiman Long
2020-01-14 18:25     ` Christoph Hellwig
2020-01-14 18:33       ` Waiman Long
2020-01-14 18:55       ` Waiman Long
2020-01-14 16:12 ` [PATCH 03/12] xfs: fix IOCB_NOWAIT handling in xfs_file_dio_aio_read Christoph Hellwig
2020-01-14 16:12 ` [PATCH 04/12] gfs2: move setting current->backing_dev_info Christoph Hellwig
2020-01-14 16:12 ` [PATCH 05/12] gfs2: fix O_SYNC write handling Christoph Hellwig
2020-02-06 15:31   ` [Cluster-devel] " Andreas Gruenbacher
2020-01-14 16:12 ` [PATCH 06/12] iomap: pass a flags value to iomap_dio_rw Christoph Hellwig
2020-01-14 16:12 ` [PATCH 07/12] iomap: allow holding i_rwsem until aio completion Christoph Hellwig
2020-01-14 16:12 ` [PATCH 08/12] ext4: hold i_rwsem until AIO completes Christoph Hellwig
2020-01-14 21:50   ` Theodore Y. Ts'o [this message]
2020-01-15  6:48     ` Christoph Hellwig
2020-01-14 16:12 ` [PATCH 09/12] gfs2: " Christoph Hellwig
2020-01-14 16:12 ` [PATCH 10/12] xfs: " Christoph Hellwig
2020-01-14 16:12 ` [PATCH 11/12] xfs: don't set IOMAP_DIO_SYNCHRONOUS for unaligned I/O Christoph Hellwig
2020-01-14 16:12 ` [PATCH 12/12] iomap: remove the inode_dio_begin/end calls Christoph Hellwig
2020-01-14 18:47 ` RFC: hold i_rwsem until aio completes Matthew Wilcox
2020-01-15  6:54   ` Christoph Hellwig
2020-01-14 19:27 ` Jason Gunthorpe
2020-01-15  6:56   ` Christoph Hellwig
2020-01-15 13:24     ` Jason Gunthorpe
2020-01-15 14:33       ` Peter Zijlstra
2020-01-15 14:49         ` Jason Gunthorpe
2020-01-15 19:03           ` Waiman Long
2020-01-15 19:07             ` Christoph Hellwig
2020-01-18 22:40         ` Matthew Wilcox
2020-01-15 15:36       ` Christoph Hellwig
2020-01-15 16:26         ` Jason Gunthorpe
2020-01-16 14:00 ` Jan Kara
2020-02-03 17:44   ` Christoph Hellwig
2020-01-18  9:28 ` Dave Chinner
2020-02-03 17:46   ` Christoph Hellwig
2020-02-03 23:02     ` Dave Chinner

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