[79/88] nbd: correct disconnect behavior

[Steven Rostedt]

3.6.11.7-rc1 stable review patch.
If anyone has any objections, please let me know.

------------------

From: Paul Clements <paul.clements@xxxxxxxxxxxx>

[ Upstream commit c378f70adbc1bbecd9e6db145019f14b2f688c7c ]

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@xxxxxxxxxxxx>
Acked-by: Rob Landley <rob@xxxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Steven Rostedt <rostedt@xxxxxxxxxxx>
---
 drivers/block/nbd.c |    6 ++++++
 include/linux/nbd.h |    1 +
 2 files changed, 7 insertions(+)

diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c
index 31e9b4b..aec3470 100644
--- a/drivers/block/nbd.c
+++ b/drivers/block/nbd.c
@@ -594,6 +594,9 @@ 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;
 	}
@@ -624,6 +627,7 @@ 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);
@@ -695,6 +699,8 @@ 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
-- 
1.7.10.4


--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/