From: Jeff Moyer <jmoyer@redhat.com>
To: axboe@kernel.dk, Chandan Rajendra <chandan@linux.vnet.ibm.com>
Cc: jack@suse.cz, linux-block@vger.kernel.org,
linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
anton@samba.org, linuxppc-dev@lists.ozlabs.org
Subject: [PATCH] direct-io: don't introduce another read of inode->i_blkbits
Date: Mon, 09 Jan 2017 16:42:58 -0500 [thread overview]
Message-ID: <x49r34bgba5.fsf@segfault.boston.devel.redhat.com> (raw)
In-Reply-To: <1483886830-23878-1-git-send-email-chandan@linux.vnet.ibm.com> (Chandan Rajendra's message of "Sun, 8 Jan 2017 20:17:10 +0530")
Commit 20ce44d545844 ("do_direct_IO: Use inode->i_blkbits to compute
block count to be cleaned") introduced a regression: if the block size
of the block device is changed while a direct I/O request is being
setup, it can result in a panic. See commit ab73857e354ab ("direct-io:
don't read inode->i_blkbits multiple times") for the reasoning, and
commit b87570f5d3496 ("Fix a crash when block device is read and block
size is changed at the same time") for a more detailed problem
description and reproducer.
Fixes: 20ce44d545844
Signed-off-by: Jeff Moyer <jmoyer@redhat.com>
---
Chandan, can you please test this to ensure this still fixes your problem?
diff --git a/fs/direct-io.c b/fs/direct-io.c
index b20adf9..c87bae4 100644
--- a/fs/direct-io.c
+++ b/fs/direct-io.c
@@ -905,8 +905,8 @@ static inline void dio_zero_block(struct dio *dio, struct dio_submit *sdio,
static int do_direct_IO(struct dio *dio, struct dio_submit *sdio,
struct buffer_head *map_bh)
{
- const unsigned i_blkbits = dio->inode->i_blkbits;
const unsigned blkbits = sdio->blkbits;
+ const unsigned i_blkbits = blkbits + sdio->blkfactor;
int ret = 0;
while (sdio->block_in_file < sdio->final_block_in_request) {
next prev parent reply other threads:[~2017-01-09 21:43 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-01-08 14:47 [PATCH] do_direct_IO: Use inode->i_blkbits to compute block count to be cleaned Chandan Rajendra
2017-01-09 13:52 ` Christoph Hellwig
2017-01-09 15:32 ` Jens Axboe
2017-01-09 16:04 ` Jeff Moyer
2017-01-09 20:20 ` Jan Kara
2017-01-09 21:42 ` Jeff Moyer [this message]
2017-01-09 21:44 ` [PATCH] direct-io: don't introduce another read of inode->i_blkbits Jens Axboe
2017-01-10 5:27 ` Chandan Rajendra
2017-01-10 20:31 ` Jens Axboe
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