Commit c378f70a authored Jul 03, 2013 by Paul Clements Committed by Linus Torvalds Jul 03, 2013

nbd: correct disconnect behavior



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@steeleye.com>
Acked-by: Rob Landley <rob@landley.net>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent 9532f149

drivers/block/nbd.c

+6 −1

Original line number	Diff line number	Diff line
		@@ -623,6 +623,8 @@ static int __nbd_ioctl(struct block_device bdev, struct nbd_device nbd,
		if (!nbd->sock)
		return -EINVAL;

		nbd->disconnect = 1;

		nbd_send_req(nbd, &sreq);
		return 0;
		}
		@@ -654,6 +656,7 @@ 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);
		@@ -743,6 +746,8 @@ 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;
		}

include/linux/nbd.h

+1 −0

Original line number	Diff line number	Diff line
		@@ -41,6 +41,7 @@ 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