[Nbd] [PATCH] 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@...124...>
---
drivers/block/nbd.c | 5 +++++
include/linux/nbd.h | 1 +
2 files changed, 6 insertions(+)
diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c
index 7fecc78..8b7664d 100644
--- a/drivers/block/nbd.c
+++ b/drivers/block/nbd.c
@@ -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);
@@ -742,6 +745,8 @@ 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 4871170..ae4981e 100644
--- a/include/linux/nbd.h
+++ b/include/linux/nbd.h
@@ -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
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