diff options
| author | Eric Blake <eblake@redhat.com> | 2016-10-14 13:33:16 -0500 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2016-11-02 09:28:56 +0100 |
| commit | b6f5d3b573fe43da1f9fa07b7454e4492f409411 (patch) | |
| tree | be19f967869577966cdbcfa26f1a21dfbfc5832a /include/block/nbd.h | |
| parent | 8b34a9dbc3f2c0afe3450cb20b94cc30f450e77b (diff) | |
nbd: Improve server handling of shutdown requests
NBD commit 6d34500b clarified how clients and servers are supposed
to behave before closing a connection. It added NBD_REP_ERR_SHUTDOWN
(for the server to announce it is about to go away during option
haggling, so the client should quit sending NBD_OPT_* other than
NBD_OPT_ABORT) and ESHUTDOWN (for the server to announce it is about
to go away during transmission, so the client should quit sending
NBD_CMD_* other than NBD_CMD_DISC). It also clarified that
NBD_OPT_ABORT gets a reply, while NBD_CMD_DISC does not.
This patch merely adds the missing reply to NBD_OPT_ABORT and teaches
the client to recognize server errors. Actually teaching the server
to send NBD_REP_ERR_SHUTDOWN or ESHUTDOWN would require knowing that
the server has been requested to shut down soon (maybe we could do
that by installing a SIGINT handler in qemu-nbd, which transitions
from RUNNING to a new state that waits for the client to react,
rather than just out-right quitting - but that's a bigger task for
another day).
Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <1476469998-28592-15-git-send-email-eblake@redhat.com>
[Move dummy ESHUTDOWN to include/qemu/osdep.h. - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'include/block/nbd.h')
| -rw-r--r-- | include/block/nbd.h | 13 |
1 files changed, 9 insertions, 4 deletions
diff --git a/include/block/nbd.h b/include/block/nbd.h index d326308656..eea7ef0536 100644 --- a/include/block/nbd.h +++ b/include/block/nbd.h @@ -83,12 +83,17 @@ typedef struct NBDReply NBDReply; #define NBD_FLAG_C_NO_ZEROES (1 << 1) /* End handshake without zeroes. */ /* Reply types. */ +#define NBD_REP_ERR(value) ((UINT32_C(1) << 31) | (value)) + #define NBD_REP_ACK (1) /* Data sending finished. */ #define NBD_REP_SERVER (2) /* Export description. */ -#define NBD_REP_ERR_UNSUP ((UINT32_C(1) << 31) | 1) /* Unknown option. */ -#define NBD_REP_ERR_POLICY ((UINT32_C(1) << 31) | 2) /* Server denied */ -#define NBD_REP_ERR_INVALID ((UINT32_C(1) << 31) | 3) /* Invalid length. */ -#define NBD_REP_ERR_TLS_REQD ((UINT32_C(1) << 31) | 5) /* TLS required */ + +#define NBD_REP_ERR_UNSUP NBD_REP_ERR(1) /* Unknown option */ +#define NBD_REP_ERR_POLICY NBD_REP_ERR(2) /* Server denied */ +#define NBD_REP_ERR_INVALID NBD_REP_ERR(3) /* Invalid length */ +#define NBD_REP_ERR_PLATFORM NBD_REP_ERR(4) /* Not compiled in */ +#define NBD_REP_ERR_TLS_REQD NBD_REP_ERR(5) /* TLS required */ +#define NBD_REP_ERR_SHUTDOWN NBD_REP_ERR(7) /* Server shutting down */ /* Request flags, sent from client to server during transmission phase */ #define NBD_CMD_FLAG_FUA (1 << 0) |