NAME
nbd_clear_meta_contexts - reset the list of requested meta contexts
SYNOPSIS
#include
<libnbd.h>
int nbd_clear_meta_contexts (
struct nbd_handle *h
);
DESCRIPTION
During connection libnbd can negotiate zero or more metadata contexts with the server. Metadata contexts are features (such as "base:allocation") which describe information returned by the nbd_block_status_64(3) command (for "base:allocation" this is whether blocks of data are allocated, zero or sparse).
This command resets the list of meta contexts to request back to an empty list, for re-population by further use of nbd_add_meta_context(3). It is primarily useful when option negotiation mode is selected (see nbd_set_opt_mode(3)), for altering the list of attempted contexts between subsequent export queries.
RETURN VALUE
If the call is successful the function returns 0.
ERRORS
On error -1 is returned.
Refer to "ERROR HANDLING" in libnbd(3) for how to get further details of the error.
The following parameters must not be NULL: "h". For more information see "Non-NULL parameters" in libnbd(3).
HANDLE STATE
nbd_clear_meta_contexts can be called when the handle is in the following states:
┌─────────────────────────────────────┬─────────────────────────┐
│ Handle created, before connecting │ ✅
allowed │
│ Connecting │ ❌ error │
│ Connecting & handshaking (opt_mode) │
✅ allowed │
│ Connected to the server │ ❌ error
│
│ Connection shut down │ ❌ error │
│ Handle dead │ ❌ error │
└─────────────────────────────────────┴─────────────────────────┘
VERSION
This function first appeared in libnbd 1.6.
If you need to test if this function is available at compile time check if the following macro is defined:
#define LIBNBD_HAVE_NBD_CLEAR_META_CONTEXTS 1
SEE ALSO
nbd_add_meta_context(3), nbd_block_status_64(3), nbd_can_meta_context(3), nbd_create(3), nbd_get_meta_context(3), nbd_get_nr_meta_contexts(3), nbd_set_opt_mode(3), libnbd(3).
AUTHORS
Eric Blake
Richard W.M. Jones
COPYRIGHT
Copyright Red Hat
LICENSE
This library is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version.
This library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public License along with this library; if not, write to the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA