---------- 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@...1514......>
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@...1515...4...>
Acked-by: Rob Landley <
rob@...1361...>
Signed-off-by: Andrew Morton <
akpm@...133...>
Signed-off-by: Linus Torvalds <
torvalds@...133...>
[xr: Backported to 3.4: adjust context]
Signed-off-by: Rui Xiang <
rui.xiang@...1511...>
---
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