1nbd_set_request_block_size(3)       LIBNBD       nbd_set_request_block_size(3)
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NAME

6       nbd_set_request_block_size - control whether NBD_OPT_GO requests block
7       size
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SYNOPSIS

10        #include <libnbd.h>
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12        int nbd_set_request_block_size (
13              struct nbd_handle *h, bool request
14            );
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DESCRIPTION

17       By default, when connecting to an export, libnbd requests that the
18       server report any block size restrictions.  The NBD protocol states
19       that a server may supply block sizes regardless of whether the client
20       requests them, and libnbd will report those block sizes (see
21       nbd_get_block_size(3)); conversely, if a client does not request block
22       sizes, the server may reject the connection instead of dealing with a
23       client sending unaligned requests.  This function makes it possible to
24       test server behavior by emulating older clients.
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26       Note that even when block size is requested, the server is not
27       obligated to provide any.  Furthermore, if block sizes are provided
28       (whether or not the client requested them), libnbd enforces alignment
29       to those sizes unless nbd_set_strict_mode(3) is used to bypass client-
30       side safety checks.
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RETURN VALUE

33       If the call is successful the function returns 0.
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ERRORS

36       On error -1 is returned.
37
38       Refer to "ERROR HANDLING" in libnbd(3) for how to get further details
39       of the error.
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41       The following parameters must not be NULL: "h".  For more information
42       see "Non-NULL parameters" in libnbd(3).
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HANDLE STATE

45       The handle must be newly created, or negotiating, otherwise this call
46       will return an error.
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VERSION

49       This function first appeared in libnbd 1.12.
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51       If you need to test if this function is available at compile time check
52       if the following macro is defined:
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54        #define LIBNBD_HAVE_NBD_SET_REQUEST_BLOCK_SIZE 1
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SEE ALSO

57       nbd_create(3), nbd_get_block_size(3), nbd_get_request_block_size(3),
58       nbd_set_full_info(3), nbd_set_strict_mode(3), libnbd(3).
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AUTHORS

61       Eric Blake
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63       Richard W.M. Jones
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66       Copyright Red Hat
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LICENSE

69       This library is free software; you can redistribute it and/or modify it
70       under the terms of the GNU Lesser General Public License as published
71       by the Free Software Foundation; either version 2 of the License, or
72       (at your option) any later version.
73
74       This library is distributed in the hope that it will be useful, but
75       WITHOUT ANY WARRANTY; without even the implied warranty of
76       MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
77       Lesser General Public License for more details.
78
79       You should have received a copy of the GNU Lesser General Public
80       License along with this library; if not, write to the Free Software
81       Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
82       02110-1301 USA
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86libnbd-1.16.5                     2023-09-26     nbd_set_request_block_size(3)
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