1nbd_aio_block_status(3) LIBNBD nbd_aio_block_status(3)
2
6 nbd_aio_block_status - send block status command, with 32-bit callback
7
9 #include <libnbd.h>
10 typedef struct {
12 int (*callback) (void *user_data,
13 const char *metacontext,
14 uint64_t offset, uint32_t *entries,
15 size_t nr_entries, int *error);
16 void *user_data;
17 void (*free) (void *user_data);
18 } nbd_extent_callback;
19 typedef struct {
21 int (*callback) (void *user_data, int *error);
22 void *user_data;
23 void (*free) (void *user_data);
24 } nbd_completion_callback;
25 int64_t nbd_aio_block_status (
27 struct nbd_handle *h, uint64_t count,
28 uint64_t offset,
29 nbd_extent_callback extent_callback,
30 nbd_completion_callback completion_callback,
31 uint32_t flags
32 );
33
35 Send the block status command to the NBD server.
36 To check if the command completed, call nbd_aio_command_completed(3).
38 Or supply the optional "completion_callback" which will be invoked as
39 described in "Completion callbacks" in libnbd(3).
40 Other parameters behave as documented in nbd_block_status(3).
42 This function is inherently limited to 32-bit values. If the server
44 replies with a larger extent, the length of that extent will be
45 truncated to just below 32 bits and any further extents from the server
46 will be ignored. If the server replies with a status value larger than
47 32 bits (only possible when extended headers are in use), the callback
48 function will be passed an "EOVERFLOW" error. To get the full extent
49 information from a server that supports 64-bit extents, you must use
50 nbd_aio_block_status_64(3).
51 By default, libnbd will reject attempts to use this function with
53 parameters that are likely to result in server failure, such as
54 requesting an unknown command flag. The nbd_set_strict_mode(3)
55 function can be used to alter which scenarios should await a server
56 reply rather than failing fast.
57
59 This call returns the 64 bit cookie of the command. The cookie is ≥ 1.
60 Cookies are unique (per libnbd handle, not globally).
61
63 On error -1 is returned.
64 Refer to "ERROR HANDLING" in libnbd(3) for how to get further details
66 of the error.
67 The following parameters must not be NULL: "h". For more information
69 see "Non-NULL parameters" in libnbd(3).
70
72 The handle must be connected with the server, otherwise this call will
73 return an error.
74
76 This function first appeared in libnbd 1.0.
77 If you need to test if this function is available at compile time check
79 if the following macro is defined:
80 #define LIBNBD_HAVE_NBD_AIO_BLOCK_STATUS 1
82
84 nbd_aio_block_status_64(3), nbd_aio_command_completed(3),
85 nbd_block_status(3), nbd_can_meta_context(3), nbd_create(3),
86 nbd_set_strict_mode(3), "Issuing asynchronous commands" in libnbd(3),
87 libnbd(3).
88
90 Eric Blake
91 Richard W.M. Jones
93
95 Copyright Red Hat
96
98 This library is free software; you can redistribute it and/or modify it
99 under the terms of the GNU Lesser General Public License as published
100 by the Free Software Foundation; either version 2 of the License, or
101 (at your option) any later version.
102 This library is distributed in the hope that it will be useful, but
104 WITHOUT ANY WARRANTY; without even the implied warranty of
105 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
106 Lesser General Public License for more details.
107 You should have received a copy of the GNU Lesser General Public
109 License along with this library; if not, write to the Free Software
110 Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
111 02110-1301 USA
112libnbd-1.18.1 2023-10-31 nbd_aio_block_status(3)