From: "Theodore Ts'o" <tytso@mit.edu>
To: Jan Kara <jack@suse.cz>
Cc: linux-fsdevel@vger.kernel.org,
Matthew Wilcox <willy@infradead.org>,
linux-ext4@vger.kernel.org
Subject: Re: [PATCH 0/3 RFC] fs: Hole punch vs page cache filling races
Date: Fri, 2 Apr 2021 15:34:13 -0400 [thread overview]
Message-ID: <YGdxtbun4bT/Mko4@mit.edu> (raw)
In-Reply-To: <20210120160611.26853-1-jack@suse.cz>
On Wed, Jan 20, 2021 at 05:06:08PM +0100, Jan Kara wrote:
>
> Amir has reported [1] a that ext4 has a potential issues when reads can race
> with hole punching possibly exposing stale data from freed blocks or even
> corrupting filesystem when stale mapping data gets used for writeout. The
> problem is that during hole punching, new page cache pages can get instantiated
> in a punched range after truncate_inode_pages() has run but before the
> filesystem removes blocks from the file. In principle any filesystem
> implementing hole punching thus needs to implement a mechanism to block
> instantiating page cache pages during hole punching to avoid this race. This is
> further complicated by the fact that there are multiple places that can
> instantiate pages in page cache. We can have regular read(2) or page fault
> doing this but fadvise(2) or madvise(2) can also result in reading in page
> cache pages through force_page_cache_readahead().
What's the current status of this patch set? I'm going through
pending patches and it looks like folks don't like Jan's proposed
solution. What are next steps?
Thanks,
- Ted
next prev parent reply other threads:[~2021-04-02 19:34 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-20 16:06 [PATCH 0/3 RFC] fs: Hole punch vs page cache filling races Jan Kara
2021-01-20 16:06 ` [PATCH 1/3] mm: Do not pass iter into generic_file_buffered_read_get_pages() Jan Kara
2021-01-20 16:18 ` Christoph Hellwig
2021-01-20 16:06 ` [PATCH 2/3] mm: Provide address_space operation for filling pages for read Jan Kara
2021-01-20 16:20 ` Christoph Hellwig
2021-01-20 17:27 ` Jan Kara
2021-01-20 17:28 ` Christoph Hellwig
2021-01-20 17:56 ` Matthew Wilcox
2021-04-02 21:17 ` Kent Overstreet
2021-04-06 12:21 ` Jan Kara
2021-01-20 16:06 ` [PATCH 3/3] ext4: Fix stale data exposure when read races with hole punch Jan Kara
2021-01-21 19:27 ` [PATCH 0/3 RFC] fs: Hole punch vs page cache filling races Matthew Wilcox
2021-01-22 14:32 ` Jan Kara
2021-04-02 19:34 ` Theodore Ts'o [this message]
2021-04-06 12:17 ` Jan Kara
2021-04-06 16:45 ` Theodore Ts'o
2021-04-06 16:50 ` Theodore Ts'o
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