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2d82148859
The Linux nbd driver recently increased the maximum supported request
size up to 32 MB:
commit 078be02b80359a541928c899c2631f39628f56df
Author: Michal Belczyk <belczyk@bsd.krakow.pl>
Date: Tue Apr 30 15:28:28 2013 -0700
nbd: increase default and max request sizes
Raise the default max request size for nbd to 128KB (from 127KB) to get it
4KB aligned. This patch also allows the max request size to be increased
(via /sys/block/nbd<x>/queue/max_sectors_kb) to 32MB.
QEMU's 1 MB buffers are too small to handle these requests.
This patch allocates data buffers dynamically and allows up to 32 MB per
request.
Reported-by: Nick Thomas <nick@bytemark.co.uk>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
101 lines
3.3 KiB
C
101 lines
3.3 KiB
C
/*
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* Copyright (C) 2005 Anthony Liguori <anthony@codemonkey.ws>
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*
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* Network Block Device
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; under version 2 of the License.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, see <http://www.gnu.org/licenses/>.
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*/
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#ifndef NBD_H
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#define NBD_H
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#include <sys/types.h>
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#include "qemu-common.h"
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#include "qemu/option.h"
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struct nbd_request {
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uint32_t magic;
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uint32_t type;
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uint64_t handle;
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uint64_t from;
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uint32_t len;
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} QEMU_PACKED;
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struct nbd_reply {
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uint32_t magic;
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uint32_t error;
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uint64_t handle;
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} QEMU_PACKED;
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#define NBD_FLAG_HAS_FLAGS (1 << 0) /* Flags are there */
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#define NBD_FLAG_READ_ONLY (1 << 1) /* Device is read-only */
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#define NBD_FLAG_SEND_FLUSH (1 << 2) /* Send FLUSH */
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#define NBD_FLAG_SEND_FUA (1 << 3) /* Send FUA (Force Unit Access) */
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#define NBD_FLAG_ROTATIONAL (1 << 4) /* Use elevator algorithm - rotational media */
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#define NBD_FLAG_SEND_TRIM (1 << 5) /* Send TRIM (discard) */
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#define NBD_CMD_MASK_COMMAND 0x0000ffff
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#define NBD_CMD_FLAG_FUA (1 << 16)
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enum {
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NBD_CMD_READ = 0,
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NBD_CMD_WRITE = 1,
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NBD_CMD_DISC = 2,
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NBD_CMD_FLUSH = 3,
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NBD_CMD_TRIM = 4
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};
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#define NBD_DEFAULT_PORT 10809
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/* Maximum size of a single READ/WRITE data buffer */
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#define NBD_MAX_BUFFER_SIZE (32 * 1024 * 1024)
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ssize_t nbd_wr_sync(int fd, void *buffer, size_t size, bool do_read);
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int tcp_socket_incoming(const char *address, uint16_t port);
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int tcp_socket_incoming_spec(const char *address_and_port);
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int tcp_socket_outgoing_opts(QemuOpts *opts);
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int unix_socket_outgoing(const char *path);
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int unix_socket_incoming(const char *path);
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int nbd_receive_negotiate(int csock, const char *name, uint32_t *flags,
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off_t *size, size_t *blocksize);
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int nbd_init(int fd, int csock, uint32_t flags, off_t size, size_t blocksize);
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ssize_t nbd_send_request(int csock, struct nbd_request *request);
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ssize_t nbd_receive_reply(int csock, struct nbd_reply *reply);
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int nbd_client(int fd);
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int nbd_disconnect(int fd);
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typedef struct NBDExport NBDExport;
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typedef struct NBDClient NBDClient;
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NBDExport *nbd_export_new(BlockDriverState *bs, off_t dev_offset,
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off_t size, uint32_t nbdflags,
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void (*close)(NBDExport *));
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void nbd_export_close(NBDExport *exp);
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void nbd_export_get(NBDExport *exp);
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void nbd_export_put(NBDExport *exp);
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BlockDriverState *nbd_export_get_blockdev(NBDExport *exp);
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NBDExport *nbd_export_find(const char *name);
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void nbd_export_set_name(NBDExport *exp, const char *name);
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void nbd_export_close_all(void);
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NBDClient *nbd_client_new(NBDExport *exp, int csock,
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void (*close)(NBDClient *));
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void nbd_client_close(NBDClient *client);
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void nbd_client_get(NBDClient *client);
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void nbd_client_put(NBDClient *client);
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#endif
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