nbd: fixes to read-only handling

We do not need BLKROSET if the kernel supports setting flags.
Also, always do BLKROSET even for a read-write export, otherwise
the read-only state remains "sticky" after the invocation of
"qemu-nbd -r".

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Paolo Bonzini 2012-11-13 10:34:17 +01:00
parent 4057725f35
commit c8969eded2

11
nbd.c
View file

@ -596,8 +596,9 @@ int nbd_init(int fd, int csock, uint32_t flags, off_t size, size_t blocksize)
return -serrno; return -serrno;
} }
if (flags & NBD_FLAG_READ_ONLY) { if (ioctl(fd, NBD_SET_FLAGS, flags) < 0) {
int read_only = 1; if (errno == ENOTTY) {
int read_only = (flags & NBD_FLAG_READ_ONLY) != 0;
TRACE("Setting readonly attribute"); TRACE("Setting readonly attribute");
if (ioctl(fd, BLKROSET, (unsigned long) &read_only) < 0) { if (ioctl(fd, BLKROSET, (unsigned long) &read_only) < 0) {
@ -605,14 +606,12 @@ int nbd_init(int fd, int csock, uint32_t flags, off_t size, size_t blocksize)
LOG("Failed setting read-only attribute"); LOG("Failed setting read-only attribute");
return -serrno; return -serrno;
} }
} } else {
if (ioctl(fd, NBD_SET_FLAGS, flags) < 0
&& errno != ENOTTY) {
int serrno = errno; int serrno = errno;
LOG("Failed setting flags"); LOG("Failed setting flags");
return -serrno; return -serrno;
} }
}
TRACE("Negotiation ended"); TRACE("Negotiation ended");