cd7fca952c
The builtin NBD server uses its own BlockBackend now instead of reusing the monitor/guest device one. This means that it has its own writethrough setting now. The builtin NBD server always uses writeback caching now regardless of whether the guest device has WCE enabled. qemu-nbd respects the cache mode given on the command line. We still need to keep a reference to the monitor BB because we put an eject notifier on it, but we don't use it for any I/O. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com>
129 lines
4.5 KiB
C
129 lines
4.5 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 "qemu-common.h"
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#include "qemu/option.h"
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#include "io/channel-socket.h"
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#include "crypto/tlscreds.h"
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/* Note: these are _NOT_ the same as the network representation of an NBD
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* request and reply!
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*/
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struct nbd_request {
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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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uint32_t type;
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};
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struct nbd_reply {
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uint64_t handle;
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uint32_t error;
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};
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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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/* New-style global flags. */
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#define NBD_FLAG_FIXED_NEWSTYLE (1 << 0) /* Fixed newstyle protocol. */
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/* New-style client flags. */
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#define NBD_FLAG_C_FIXED_NEWSTYLE (1 << 0) /* Fixed newstyle protocol. */
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/* Reply types. */
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#define NBD_REP_ACK (1) /* Data sending finished. */
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#define NBD_REP_SERVER (2) /* Export description. */
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#define NBD_REP_ERR_UNSUP ((UINT32_C(1) << 31) | 1) /* Unknown option. */
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#define NBD_REP_ERR_POLICY ((UINT32_C(1) << 31) | 2) /* Server denied */
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#define NBD_REP_ERR_INVALID ((UINT32_C(1) << 31) | 3) /* Invalid length. */
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#define NBD_REP_ERR_TLS_REQD ((UINT32_C(1) << 31) | 5) /* TLS required */
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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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/* Maximum size of an export name. The NBD spec requires 256 and
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* suggests that servers support up to 4096, but we stick to only the
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* required size so that we can stack-allocate the names, and because
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* going larger would require an audit of more code to make sure we
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* aren't overflowing some other buffer. */
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#define NBD_MAX_NAME_SIZE 256
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ssize_t nbd_wr_syncv(QIOChannel *ioc,
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struct iovec *iov,
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size_t niov,
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size_t length,
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bool do_read);
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int nbd_receive_negotiate(QIOChannel *ioc, const char *name, uint16_t *flags,
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QCryptoTLSCreds *tlscreds, const char *hostname,
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QIOChannel **outioc,
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off_t *size, Error **errp);
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int nbd_init(int fd, QIOChannelSocket *sioc, uint16_t flags, off_t size);
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ssize_t nbd_send_request(QIOChannel *ioc, struct nbd_request *request);
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ssize_t nbd_receive_reply(QIOChannel *ioc, 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, off_t size,
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uint16_t nbdflags, void (*close)(NBDExport *),
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bool writethrough, BlockBackend *on_eject_blk,
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Error **errp);
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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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BlockBackend *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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void nbd_client_new(NBDExport *exp,
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QIOChannelSocket *sioc,
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QCryptoTLSCreds *tlscreds,
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const char *tlsaclname,
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void (*close)(NBDClient *));
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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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