| From c378f70adbc1bbecd9e6db145019f14b2f688c7c Mon Sep 17 00:00:00 2001 |
| From: Paul Clements <paul.clements@steeleye.com> |
| Date: Wed, 3 Jul 2013 15:09:04 -0700 |
| Subject: nbd: correct disconnect behavior |
| |
| From: Paul Clements <paul.clements@steeleye.com> |
| |
| 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@steeleye.com> |
| Acked-by: Rob Landley <rob@landley.net> |
| Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
| Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| |
| --- |
| drivers/block/nbd.c | 7 ++++++- |
| include/linux/nbd.h | 1 + |
| 2 files changed, 7 insertions(+), 1 deletion(-) |
| |
| --- a/drivers/block/nbd.c |
| +++ b/drivers/block/nbd.c |
| @@ -623,8 +623,10 @@ static int __nbd_ioctl(struct block_devi |
| if (!nbd->sock) |
| return -EINVAL; |
| |
| + nbd->disconnect = 1; |
| + |
| nbd_send_req(nbd, &sreq); |
| - return 0; |
| + return 0; |
| } |
| |
| case NBD_CLEAR_SOCK: { |
| @@ -654,6 +656,7 @@ static int __nbd_ioctl(struct block_devi |
| 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_devi |
| 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; |
| } |
| |
| --- 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 |