On 7/31/2019 5:13 AM, SunKe wrote:
> From: Munehisa Kamata <kamatam@xxxxxxxxxx>
>
> 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@xxxxxxxxxxxxxxx
> Cc: Ratna Manoj Bolla <manoj.br@xxxxxxxxx>
> Cc: nbd@xxxxxxxxxxxxxxxx
> Cc: stable@xxxxxxxxxxxxxxx
> Cc: David Woodhouse <dwmw@xxxxxxxxxx>
> Signed-off-by: Munehisa Kamata <kamatam@xxxxxxxxxx>
>
> ---
> I reproduced this phenomenon on the fat file system.
> reproduce steps :
> 1.Establish a nbd connection.
> 2.Run two threads:one do mount and umount,anther one do clear_sock ioctl
> 3.Then hit the BUG_ON.
>
> v2: Delete a link.
>
> Signed-off-by: SunKe <sunke32@xxxxxxxxxx>
>
> drivers/block/nbd.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c
> index 9bcde23..e21d2de 100644
> --- a/drivers/block/nbd.c
> +++ b/drivers/block/nbd.c
> @@ -1231,7 +1231,7 @@ static void nbd_clear_sock_ioctl(struct nbd_device *nbd,
> 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))
>
Hi SunKe,
I accidentally included the link in the original one. Sorry about that and thanks
for picking this up.
Regards,
Munehsia
