[79/88] nbd: correct disconnect behavior

Steven Rostedt
2013-08-13T16:36:42Z

[-- Attachment #1: 0079-nbd-correct-disconnect-behavior.patch --]
[-- Type: text/plain, Size: 2605 bytes --]

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

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

From: Paul Clements <paul.clements@steeleye.com>

[ 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@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>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
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