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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, linux-block@vger.kernel.org,
        Ratna Manoj Bolla <manoj.br@gmail.com>, nbd@other.debian.org,
        David Woodhouse <dwmw@amazon.com>,
        Josef Bacik <josef@toxicpanda.com>,
        Munehisa Kamata <kamatam@amazon.com>,
        Jens Axboe <axboe@kernel.dk>
Subject: [PATCH 5.2 117/131] nbd: replace kill_bdev() with __invalidate_device() again
Date:   Mon,  5 Aug 2019 15:03:24 +0200
Message-Id: <20190805124959.791932900@linuxfoundation.org>
In-Reply-To: <20190805124951.453337465@linuxfoundation.org>
References: <20190805124951.453337465@linuxfoundation.org>
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From: Munehisa Kamata <kamatam@amazon.com>

commit 2b5c8f0063e4b263cf2de82029798183cf85c320 upstream.

Commit abbbdf12497d ("replace kill_bdev() with __invalidate_device()")
once did this, but 29eaadc03649 ("nbd: stop using the bdev everywhere")
resurrected kill_bdev() and it has been there since then. So buffer_head
mappings still get killed on a server disconnection, and we can still
hit the BUG_ON on a filesystem on the top of the nbd device.

  EXT4-fs (nbd0): mounted filesystem with ordered data mode. Opts: (null)
  block nbd0: Receive control failed (result -32)
  block nbd0: shutting down sockets
  print_req_error: I/O error, dev nbd0, sector 66264 flags 3000
  EXT4-fs warning (device nbd0): htree_dirblock_to_tree:979: inode #2: lblock 0: comm ls: error -5 reading directory block
  print_req_error: I/O error, dev nbd0, sector 2264 flags 3000
  EXT4-fs error (device nbd0): __ext4_get_inode_loc:4690: inode #2: block 283: comm ls: unable to read itable block
  EXT4-fs error (device nbd0) in ext4_reserve_inode_write:5894: IO failure
  ------------[ cut here ]------------
  kernel BUG at fs/buffer.c:3057!
  invalid opcode: 0000 [#1] SMP PTI
  CPU: 7 PID: 40045 Comm: jbd2/nbd0-8 Not tainted 5.1.0-rc3+ #4
  Hardware name: Amazon EC2 m5.12xlarge/, BIOS 1.0 10/16/2017
  RIP: 0010:submit_bh_wbc+0x18b/0x190
  ...
  Call Trace:
   jbd2_write_superblock+0xf1/0x230 [jbd2]
   ? account_entity_enqueue+0xc5/0xf0
   jbd2_journal_update_sb_log_tail+0x94/0xe0 [jbd2]
   jbd2_journal_commit_transaction+0x12f/0x1d20 [jbd2]
   ? __switch_to_asm+0x40/0x70
   ...
   ? lock_timer_base+0x67/0x80
   kjournald2+0x121/0x360 [jbd2]
   ? remove_wait_queue+0x60/0x60
   kthread+0xf8/0x130
   ? commit_timeout+0x10/0x10 [jbd2]
   ? kthread_bind+0x10/0x10
   ret_from_fork+0x35/0x40

With __invalidate_device(), I no longer hit the BUG_ON with sync or
unmount on the disconnected device.

Fixes: 29eaadc03649 ("nbd: stop using the bdev everywhere")
Cc: linux-block@vger.kernel.org
Cc: Ratna Manoj Bolla <manoj.br@gmail.com>
Cc: nbd@other.debian.org
Cc: stable@vger.kernel.org
Cc: David Woodhouse <dwmw@amazon.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Munehisa Kamata <kamatam@amazon.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/block/nbd.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/block/nbd.c
+++ b/drivers/block/nbd.c
@@ -1229,7 +1229,7 @@ static void nbd_clear_sock_ioctl(struct
 				 struct block_device *bdev)
 {
 	sock_shutdown(nbd);
-	kill_bdev(bdev);
+	__invalidate_device(bdev, true);
 	nbd_bdev_reset(bdev);
 	if (test_and_clear_bit(NBD_HAS_CONFIG_REF,
 			       &nbd->config->runtime_flags))