diff options
| author | Eric Blake <eblake@redhat.com> | 2016-07-21 13:34:46 -0600 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2016-08-03 18:44:56 +0200 |
| commit | 7423f417827146f956df820f172d0bf80a489495 (patch) | |
| tree | c344d494cc4fab46a7bb1daacb0088bc35e9ee1f /nbd/server.c | |
| parent | 5bee0f4717c4c67394aaade0c5a9cee3d42cc614 (diff) | |
nbd: Limit nbdflags to 16 bits
Rather than asserting that nbdflags is within range, just give
it the correct type to begin with :) nbdflags corresponds to
the per-export portion of NBD Protocol "transmission flags", which
is 16 bits in response to NBD_OPT_EXPORT_NAME and NBD_OPT_GO.
Furthermore, upstream NBD has never passed the global flags to
the kernel via ioctl(NBD_SET_FLAGS) (the ioctl was first
introduced in NBD 2.9.22; then a latent bug in NBD 3.1 actually
tried to OR the global flags with the transmission flags, with
the disaster that the addition of NBD_FLAG_NO_ZEROES in 3.9
caused all earlier NBD 3.x clients to treat every export as
read-only; NBD 3.10 and later intentionally clip things to 16
bits to pass only transmission flags). Qemu should follow suit,
since the current two global flags (NBD_FLAG_FIXED_NEWSTYLE
and NBD_FLAG_NO_ZEROES) have no impact on the kernel's behavior
during transmission.
CC: qemu-stable@nongnu.org
Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <1469129688-22848-3-git-send-email-eblake@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'nbd/server.c')
| -rw-r--r-- | nbd/server.c | 10 |
1 files changed, 4 insertions, 6 deletions
diff --git a/nbd/server.c b/nbd/server.c index 3c1e2b336b..80fbb4da1d 100644 --- a/nbd/server.c +++ b/nbd/server.c @@ -63,7 +63,7 @@ struct NBDExport { char *name; off_t dev_offset; off_t size; - uint32_t nbdflags; + uint16_t nbdflags; QTAILQ_HEAD(, NBDClient) clients; QTAILQ_ENTRY(NBDExport) next; @@ -544,8 +544,8 @@ static coroutine_fn int nbd_negotiate(NBDClientNewData *data) NBDClient *client = data->client; char buf[8 + 8 + 8 + 128]; int rc; - const int myflags = (NBD_FLAG_HAS_FLAGS | NBD_FLAG_SEND_TRIM | - NBD_FLAG_SEND_FLUSH | NBD_FLAG_SEND_FUA); + const uint16_t myflags = (NBD_FLAG_HAS_FLAGS | NBD_FLAG_SEND_TRIM | + NBD_FLAG_SEND_FLUSH | NBD_FLAG_SEND_FUA); bool oldStyle; /* Old style negotiation header without options @@ -575,7 +575,6 @@ static coroutine_fn int nbd_negotiate(NBDClientNewData *data) oldStyle = client->exp != NULL && !client->tlscreds; if (oldStyle) { - assert ((client->exp->nbdflags & ~65535) == 0); TRACE("advertising size %" PRIu64 " and flags %x", client->exp->size, client->exp->nbdflags | myflags); stq_be_p(buf + 8, NBD_CLIENT_MAGIC); @@ -606,7 +605,6 @@ static coroutine_fn int nbd_negotiate(NBDClientNewData *data) goto fail; } - assert ((client->exp->nbdflags & ~65535) == 0); TRACE("advertising size %" PRIu64 " and flags %x", client->exp->size, client->exp->nbdflags | myflags); stq_be_p(buf + 18, client->exp->size); @@ -810,7 +808,7 @@ static void nbd_eject_notifier(Notifier *n, void *data) } NBDExport *nbd_export_new(BlockBackend *blk, off_t dev_offset, off_t size, - uint32_t nbdflags, void (*close)(NBDExport *), + uint16_t nbdflags, void (*close)(NBDExport *), Error **errp) { NBDExport *exp = g_malloc0(sizeof(NBDExport)); |