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| 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 /nbd/nbd-internal.h | |
| parent | 8b34a9dbc3f2c0afe3450cb20b94cc30f450e77b (diff) | |
| download | qemu-b6f5d3b573fe43da1f9fa07b7454e4492f409411.tar.gz | |
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 'nbd/nbd-internal.h')
| -rw-r--r-- | nbd/nbd-internal.h | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/nbd/nbd-internal.h b/nbd/nbd-internal.h index dd57e18833..eee20abc25 100644 --- a/nbd/nbd-internal.h +++ b/nbd/nbd-internal.h @@ -92,6 +92,7 @@ #define NBD_ENOMEM 12 #define NBD_EINVAL 22 #define NBD_ENOSPC 28 +#define NBD_ESHUTDOWN 108 static inline ssize_t read_sync(QIOChannel *ioc, void *buffer, size_t size) { |