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authorEric Blake <eblake@redhat.com>2016-07-21 13:34:46 -0600
committerPaolo Bonzini <pbonzini@redhat.com>2016-08-03 18:44:56 +0200
commit7423f417827146f956df820f172d0bf80a489495 (patch)
treec344d494cc4fab46a7bb1daacb0088bc35e9ee1f /include/block
parent5bee0f4717c4c67394aaade0c5a9cee3d42cc614 (diff)
downloadqemu-7423f417827146f956df820f172d0bf80a489495.tar.gz
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 'include/block')
-rw-r--r--include/block/nbd.h6
1 files changed, 3 insertions, 3 deletions
diff --git a/include/block/nbd.h b/include/block/nbd.h
index cb91820f38..1897557a9b 100644
--- a/include/block/nbd.h
+++ b/include/block/nbd.h
@@ -90,11 +90,11 @@ ssize_t nbd_wr_syncv(QIOChannel *ioc,
size_t niov,
size_t length,
bool do_read);
-int nbd_receive_negotiate(QIOChannel *ioc, const char *name, uint32_t *flags,
+int nbd_receive_negotiate(QIOChannel *ioc, const char *name, uint16_t *flags,
QCryptoTLSCreds *tlscreds, const char *hostname,
QIOChannel **outioc,
off_t *size, Error **errp);
-int nbd_init(int fd, QIOChannelSocket *sioc, uint32_t flags, off_t size);
+int nbd_init(int fd, QIOChannelSocket *sioc, uint16_t flags, off_t size);
ssize_t nbd_send_request(QIOChannel *ioc, struct nbd_request *request);
ssize_t nbd_receive_reply(QIOChannel *ioc, struct nbd_reply *reply);
int nbd_client(int fd);
@@ -104,7 +104,7 @@ typedef struct NBDExport NBDExport;
typedef struct NBDClient NBDClient;
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);
void nbd_export_close(NBDExport *exp);
void nbd_export_get(NBDExport *exp);