From: Eric Biggers <ebiggers3@gmail.com>
To: Christoph Hellwig <hch@infradead.org>
Cc: linux-ext4@vger.kernel.org, Theodore Ts'o <tytso@mit.edu>,
Andreas Dilger <adilger.kernel@dilger.ca>,
Nick Alcock <nick.alcock@oracle.com>,
Eric Biggers <ebiggers@google.com>,
stable@vger.kernel.org
Subject: Re: [PATCH] ext4: evict inline data when writing to memory map
Date: Tue, 14 Mar 2017 16:32:39 -0700 [thread overview]
Message-ID: <20170314233239.GA127087@gmail.com> (raw)
In-Reply-To: <20170313233313.GA23580@infradead.org>
On Mon, Mar 13, 2017 at 04:33:13PM -0700, Christoph Hellwig wrote:
> > mkfs.ext4 -O inline_data /dev/vdb
> > mount /dev/vdb /mnt
> > xfs_io -f /mnt/file \
> > -c 'pwrite 0 1' \
> > -c 'mmap -w 0 1m' \
> > -c 'mwrite 0 1' \
> > -c 'fsync'
>
> Please add this test case to xfstests.
I'm working on this, and I discovered there's still a bug. After the data is
written with mwrite, if the filesystem is then mount-cycled, the contents of the
file are the old contents rather than the new contents.
I believe this is caused by a bug in ext4_convert_inline_data(). Specifically,
the new block containing the evicted data is journalled using a buffer_head
associated with the block device. This is wrong because it can overwrite data
that is later written through non-journalled writeback.
I'll look into this more when I have time, but in any case it appears this fix
isn't complete.
Eric
next prev parent reply other threads:[~2017-03-14 23:32 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-03-13 0:47 [PATCH] ext4: evict inline data when writing to memory map Eric Biggers
2017-03-13 4:39 ` Andreas Dilger
2017-03-13 23:33 ` Christoph Hellwig
2017-03-14 23:32 ` Eric Biggers [this message]
2017-04-30 4:13 ` Theodore Ts'o
2017-05-01 22:10 ` Eric Biggers
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