Update ioctl order in nbd_init() to detect EBUSY

Update ioctl(s) in nbd_init() to detect device busy early.

Current nbd_init() issues NBD_CLEAR_SOCKET before NBD_SET_SOCKET, if issuing
"qemu-nbd -c /dev/nbd0 disk.img" twice, the second time won't detect EBUSY in
nbd_init(), but in nbd_client will report EBUSY and do clear socket (the 1st
time command will be affacted too because of no socket any more.)

No change to previous version.

Signed-off-by: Chunyan Liu <cyliu@suse.com>

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Chunyan Liu 2011-12-02 23:27:54 +08:00 committed by Paolo Bonzini
parent 7a706633e9
commit 3e05c78551

27
nbd.c
View File

@ -358,6 +358,15 @@ int nbd_receive_negotiate(int csock, const char *name, uint32_t *flags,
#ifdef __linux__
int nbd_init(int fd, int csock, uint32_t flags, off_t size, size_t blocksize)
{
TRACE("Setting NBD socket");
if (ioctl(fd, NBD_SET_SOCK, csock) == -1) {
int serrno = errno;
LOG("Failed to set NBD socket");
errno = serrno;
return -1;
}
TRACE("Setting block size to %lu", (unsigned long)blocksize);
if (ioctl(fd, NBD_SET_BLKSIZE, blocksize) == -1) {
@ -396,24 +405,6 @@ int nbd_init(int fd, int csock, uint32_t flags, off_t size, size_t blocksize)
return -1;
}
TRACE("Clearing NBD socket");
if (ioctl(fd, NBD_CLEAR_SOCK) == -1) {
int serrno = errno;
LOG("Failed clearing NBD socket");
errno = serrno;
return -1;
}
TRACE("Setting NBD socket");
if (ioctl(fd, NBD_SET_SOCK, csock) == -1) {
int serrno = errno;
LOG("Failed to set NBD socket");
errno = serrno;
return -1;
}
TRACE("Negotiation ended");
return 0;