nbd_clear_meta_contexts - reset the list of requested meta contexts
#include <libnbd.h> int nbd_clear_meta_contexts (struct nbd_handle *h);
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(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.
If the call is successful the function returns
-1 is returned.
Refer to "ERROR HANDLING" in libnbd(3) for how to get further details of the error.
The handle must be newly created, or negotiating, otherwise this call will return an error.
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
nbd_add_meta_context(3), nbd_block_status(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).
Richard W.M. Jones
Copyright (C) 2019-2021 Red Hat Inc.
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