Re: [Nbd] Fwd: [PATCH 1/3] nbd: correct disconnect behavior

[Wouter Verhelst <w@...112...>]

Op zaterdag 22 februari 2014 09:35:35 schreef Paul Clements:
> I'm guessing this is the patch they were looking for. This one had slipped
> my mind....

Yes, I was thinking the same thing -- but that only makes sense if the client 
is actually trying to persist.

> ---------- Forwarded message ----------
> From: *Rui Xiang* <rui.xiang@...1511...>
> Date: Saturday, February 22, 2014
> Subject: [PATCH 1/3] nbd: correct disconnect behavior
> To: Greg Kroah-Hartman " <gregkh@...1299...>
> Cc: stable@...25..., Ben Hutchings <ben@...1505...>, Paul
> Clements <paul.clements@...124...>, Rob Landley <rob@...1361...>
> 
> 
> From: Paul Clements <paul.clements@...124... <javascript:;>>
> 
> commit c378f70adbc1bbecd9e6db145019f14b2f688c7c upstream.
> 
> Currently, when a disconnect is requested by the user (via NBD_DISCONNECT
> ioctl) the return from NBD_DO_IT is undefined (it is usually one of
> several error codes).  This means that nbd-client does not know if a
> manual disconnect was performed or whether a network error occurred.
> Because of this, nbd-client's persist mode (which tries to reconnect after
> error, but not after manual disconnect) does not always work correctly.
> 
> This change fixes this by causing NBD_DO_IT to always return 0 if a user
> requests a disconnect.  This means that nbd-client can correctly either
> persist the connection (if an error occurred) or disconnect (if the user
> requested it).
> 
> Signed-off-by: Paul Clements <paul.clements@...124... <javascript:;>>
> Acked-by: Rob Landley <rob@...1361... <javascript:;>>
> Signed-off-by: Andrew Morton <akpm@...133... <javascript:;>>
> Signed-off-by: Linus Torvalds <torvalds@...133... <javascript:;>>
> [xr: Backported to 3.4: adjust context]
> Signed-off-by: Rui Xiang <rui.xiang@...1511... <javascript:;>>
> ---
>  drivers/block/nbd.c | 8 +++++++-
>  include/linux/nbd.h | 1 +
>  2 files changed, 8 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c
> index 386d40e..d724da5 100644
> --- a/drivers/block/nbd.c
> +++ b/drivers/block/nbd.c
> @@ -590,8 +590,11 @@ static int __nbd_ioctl(struct block_device *bdev,
> struct nbd_device *nbd,
>                 nbd_cmd(&sreq) = NBD_CMD_DISC;
>                 if (!nbd->sock)
>                         return -EINVAL;
> +
> +               nbd->disconnect = 1;
> +
>                 nbd_send_req(nbd, &sreq);
> -                return 0;
> +               return 0;
>         }
> 
>         case NBD_CLEAR_SOCK: {
> @@ -620,6 +623,7 @@ static int __nbd_ioctl(struct block_device *bdev,
> struct nbd_device *nbd,
>                                 nbd->sock = SOCKET_I(inode);
>                                 if (max_part > 0)
>                                         bdev->bd_invalidated = 1;
> +                               nbd->disconnect = 0; /* we're connected now
> */
>                                 return 0;
>                         } else {
>                                 fput(file);
> @@ -691,6 +695,8 @@ static int __nbd_ioctl(struct block_device *bdev,
> struct nbd_device *nbd,
>                 set_capacity(nbd->disk, 0);
>                 if (max_part > 0)
>                         ioctl_by_bdev(bdev, BLKRRPART, 0);
> +               if (nbd->disconnect) /* user requested, ignore socket
> errors */
> +                       return 0;
>                 return nbd->harderror;
>         }
> 
> diff --git a/include/linux/nbd.h b/include/linux/nbd.h
> index d146ca1..e6fe174 100644
> --- a/include/linux/nbd.h
> +++ b/include/linux/nbd.h
> @@ -68,6 +68,7 @@ struct nbd_device {
>         u64 bytesize;
>         pid_t pid; /* pid of nbd-client, if attached */
>         int xmit_timeout;
> +       int disconnect; /* a disconnect has been requested by user */
>  };
> 
>  #endif
> --
> 1.8.2.2

-- 
This end should point toward the ground if you want to go to space.

If it starts pointing toward space you are having a bad problem and you
will not go to space today.

  -- http://xkcd.com/1133/