To: linux-kernel@vger.kernel.org
Cc: Wei Fang <fangwei1@huawei.com>,
        Linus Torvalds <torvalds@linux-foundation.org>
From: Doug Nazar <nazard@nazar.ca>
Subject: Kernels v4.9+ cause short reads of block devices
Message-ID: <1ae53e17-e455-4f17-0280-b0dae183a449@nazar.ca>
Date: Wed, 23 Aug 2017 15:15:15 -0400
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The following commits cause short reads of block devices, however writes 
are still allowed.

c2a9737f45e2 ("vfs,mm: fix a dead loop in truncate_inode_pages_range()")
d05c5f7ba164 ("vfs,mm: fix return value of read() at s_maxbytes")

When e2fsck sees this, it thinks it's a bad sector and tries to write a 
block of nulls which overwrites the valid data.

Device is LVM over 2 x RAID-5 on an old 32bit desktop.

RO    RA   SSZ   BSZ   StartSec            Size   Device
rw  4096   512  4096          0   9748044840960 /dev/Storage/Main

Doug