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nbd: correct disconnect behavior

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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>
This commit is contained in:
Paul Clements 2013-07-03 15:09:04 -07:00 committed by Linus Torvalds
parent 9532f149ee
commit c378f70adb
2 changed files with 7 additions and 1 deletions
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7
drivers/block/nbd.c
View File

@ -623,8 +623,10 @@ 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;
return 0;
}
case NBD_CLEAR_SOCK: {
@ -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);
@ -743,6 +746,8 @@ 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;
}

1
include/linux/nbd.h
View File

@ -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