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From: Andreas Gruenbacher <agruenba@redhat.com>
To: Matthew Wilcox <willy@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>,
	linux-xfs@vger.kernel.org, Junxiao Bi <junxiao.bi@oracle.com>,
	William Kucharski <william.kucharski@oracle.com>,
	Joseph Qi <joseph.qi@linux.alibaba.com>,
	John Hubbard <jhubbard@nvidia.com>,
	LKML <linux-kernel@vger.kernel.org>,
	linux-f2fs-devel@lists.sourceforge.net,
	cluster-devel <cluster-devel@redhat.com>,
	Linux-MM <linux-mm@kvack.org>,
	ocfs2-devel@oss.oracle.com,
	linux-fsdevel <linux-fsdevel@vger.kernel.org>,
	linux-ext4 <linux-ext4@vger.kernel.org>,
	linux-erofs@lists.ozlabs.org, Christoph Hellwig <hch@lst.de>,
	linux-btrfs@vger.kernel.org,
	Steven Whitehouse <swhiteho@redhat.com>,
	Bob Peterson <rpeterso@redhat.com>
Subject: Re: [Cluster-devel] [PATCH v11 16/25] fs: Convert mpage_readpages to mpage_readahead
Date: Wed, 17 Jun 2020 00:36:13 +0200
Message-ID: <CAHc6FU4m1M7Tv4scX0UxSiVBqkL=Vcw_z-R7SufL8k7Bw=qPOw@mail.gmail.com> (raw)
In-Reply-To: <20200414150233.24495-17-willy@infradead.org>

Am Mi., 15. Apr. 2020 um 23:39 Uhr schrieb Matthew Wilcox <willy@infradead.org>:
> From: "Matthew Wilcox (Oracle)" <willy@infradead.org>
>
> Implement the new readahead aop and convert all callers (block_dev,
> exfat, ext2, fat, gfs2, hpfs, isofs, jfs, nilfs2, ocfs2, omfs, qnx6,
> reiserfs & udf).  The callers are all trivial except for GFS2 & OCFS2.

This patch leads to an ABBA deadlock in xfstest generic/095 on gfs2.

Our lock hierarchy is such that the inode cluster lock ("inode glock")
for an inode needs to be taken before any page locks in that inode's
address space. However, the readahead address space operation is
called with the pages already locked. When we try to grab the inode
glock inside gfs2_readahead, we'll deadlock with processes that are
holding that inode glock and trying to lock one of those same pages.

One possible solution is to use a trylock on the glock in
gfs2_readahead, and to give up the readahead in case of a locking
conflict. I have no idea how this is going to affect performance.

Any other ideas?

Thanks,
Andreas


  reply index

Thread overview: 47+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-04-14 15:02 [PATCH v11 00/25] Change readahead API Matthew Wilcox
2020-04-14 15:02 ` [PATCH v11 01/25] mm: Move readahead prototypes from mm.h Matthew Wilcox
2020-04-15  9:10   ` Johannes Thumshirn
2020-04-14 15:02 ` [PATCH v11 02/25] mm: Return void from various readahead functions Matthew Wilcox
2020-04-14 15:02 ` [PATCH v11 03/25] mm: Ignore return value of ->readpages Matthew Wilcox
2020-04-15  9:17   ` Johannes Thumshirn
2020-04-14 15:02 ` [PATCH v11 04/25] mm: Move readahead nr_pages check into read_pages Matthew Wilcox
2020-04-15  9:19   ` Johannes Thumshirn
2020-04-14 15:02 ` [PATCH v11 05/25] mm: Add new readahead_control API Matthew Wilcox
2020-04-15  1:17   ` Andrew Morton
2020-04-15  2:18     ` Matthew Wilcox
2020-04-15  4:56       ` Andrew Morton
2020-04-15 11:22         ` Matthew Wilcox
2020-04-14 15:02 ` [PATCH v11 06/25] mm: Use readahead_control to pass arguments Matthew Wilcox
2020-04-15  9:30   ` Johannes Thumshirn
2020-04-14 15:02 ` [PATCH v11 07/25] mm: Rename various 'offset' parameters to 'index' Matthew Wilcox
2020-04-14 15:02 ` [PATCH v11 08/25] mm: rename readahead loop variable to 'i' Matthew Wilcox
2020-04-15  9:31   ` Johannes Thumshirn
2020-04-14 15:02 ` [PATCH v11 09/25] mm: Remove 'page_offset' from readahead loop Matthew Wilcox
2020-04-14 15:02 ` [PATCH v11 10/25] mm: Put readahead pages in cache earlier Matthew Wilcox
2020-04-14 15:02 ` [PATCH v11 11/25] mm: Add readahead address space operation Matthew Wilcox
2020-04-14 15:02 ` [PATCH v11 12/25] mm: Move end_index check out of readahead loop Matthew Wilcox
2020-04-14 15:02 ` [PATCH v11 13/25] mm: Add page_cache_readahead_unbounded Matthew Wilcox
2020-04-14 15:02 ` [PATCH v11 14/25] mm: Document why we don't set PageReadahead Matthew Wilcox
2020-04-14 15:02 ` [PATCH v11 15/25] mm: Use memalloc_nofs_save in readahead path Matthew Wilcox
2020-04-14 15:02 ` [PATCH v11 16/25] fs: Convert mpage_readpages to mpage_readahead Matthew Wilcox
2020-06-16 22:36   ` Andreas Gruenbacher [this message]
2020-06-17  0:32     ` [Cluster-devel] " Matthew Wilcox
2020-06-17  0:57       ` Andreas Grünbacher
2020-06-17  2:21         ` Matthew Wilcox
2020-06-18 12:46           ` Andreas Gruenbacher
2020-06-18 15:03             ` Matthew Wilcox
2020-06-18 16:40               ` Andreas Gruenbacher
2020-04-14 15:02 ` [PATCH v11 17/25] btrfs: Convert from readpages to readahead Matthew Wilcox
2020-04-14 15:02 ` [PATCH v11 18/25] erofs: Convert uncompressed files " Matthew Wilcox
2020-04-14 15:02 ` [PATCH v11 19/25] erofs: Convert compressed " Matthew Wilcox
2020-04-21  5:42   ` Andrew Morton
2020-04-21  7:28     ` Gao Xiang
2020-04-14 15:02 ` [PATCH v11 20/25] ext4: Convert " Matthew Wilcox
2020-04-14 15:02 ` [PATCH v11 21/25] ext4: Pass the inode to ext4_mpage_readpages Matthew Wilcox
2020-04-14 15:02 ` [PATCH v11 22/25] f2fs: Convert from readpages to readahead Matthew Wilcox
2020-04-14 15:02 ` [PATCH v11 23/25] f2fs: Pass the inode to f2fs_mpage_readpages Matthew Wilcox
2020-04-14 15:02 ` [PATCH v11 24/25] fuse: Convert from readpages to readahead Matthew Wilcox
2020-04-20 11:14   ` Miklos Szeredi
2020-04-20 11:43     ` Matthew Wilcox
2020-04-20 11:54       ` Miklos Szeredi
2020-04-14 15:02 ` [PATCH v11 25/25] iomap: " Matthew Wilcox

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