dm thin metadata: fix __udivdi3 undefined on 32-bit
[linux/fpc-iii.git] / drivers / hv / hv_snapshot.c
blobfaad79ae318a63bf87ab6a3a190565fb3af96ec6
1 /*
2 * An implementation of host initiated guest snapshot.
5 * Copyright (C) 2013, Microsoft, Inc.
6 * Author : K. Y. Srinivasan <kys@microsoft.com>
8 * This program is free software; you can redistribute it and/or modify it
9 * under the terms of the GNU General Public License version 2 as published
10 * by the Free Software Foundation.
12 * This program is distributed in the hope that it will be useful, but
13 * WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
15 * NON INFRINGEMENT. See the GNU General Public License for more
16 * details.
19 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
21 #include <linux/net.h>
22 #include <linux/nls.h>
23 #include <linux/connector.h>
24 #include <linux/workqueue.h>
25 #include <linux/hyperv.h>
27 #include "hyperv_vmbus.h"
28 #include "hv_utils_transport.h"
30 #define VSS_MAJOR 5
31 #define VSS_MINOR 0
32 #define VSS_VERSION (VSS_MAJOR << 16 | VSS_MINOR)
34 #define VSS_USERSPACE_TIMEOUT (msecs_to_jiffies(10 * 1000))
37 * Global state maintained for transaction that is being processed. For a class
38 * of integration services, including the "VSS service", the specified protocol
39 * is a "request/response" protocol which means that there can only be single
40 * outstanding transaction from the host at any given point in time. We use
41 * this to simplify memory management in this driver - we cache and process
42 * only one message at a time.
44 * While the request/response protocol is guaranteed by the host, we further
45 * ensure this by serializing packet processing in this driver - we do not
46 * read additional packets from the VMBUs until the current packet is fully
47 * handled.
50 static struct {
51 int state; /* hvutil_device_state */
52 int recv_len; /* number of bytes received. */
53 struct vmbus_channel *recv_channel; /* chn we got the request */
54 u64 recv_req_id; /* request ID. */
55 struct hv_vss_msg *msg; /* current message */
56 } vss_transaction;
59 static void vss_respond_to_host(int error);
62 * This state maintains the version number registered by the daemon.
64 static int dm_reg_value;
66 static const char vss_devname[] = "vmbus/hv_vss";
67 static __u8 *recv_buffer;
68 static struct hvutil_transport *hvt;
69 static struct completion release_event;
71 static void vss_send_op(struct work_struct *dummy);
72 static void vss_timeout_func(struct work_struct *dummy);
74 static DECLARE_DELAYED_WORK(vss_timeout_work, vss_timeout_func);
75 static DECLARE_WORK(vss_send_op_work, vss_send_op);
77 static void vss_poll_wrapper(void *channel)
79 /* Transaction is finished, reset the state here to avoid races. */
80 vss_transaction.state = HVUTIL_READY;
81 hv_vss_onchannelcallback(channel);
85 * Callback when data is received from user mode.
88 static void vss_timeout_func(struct work_struct *dummy)
91 * Timeout waiting for userspace component to reply happened.
93 pr_warn("VSS: timeout waiting for daemon to reply\n");
94 vss_respond_to_host(HV_E_FAIL);
96 hv_poll_channel(vss_transaction.recv_channel, vss_poll_wrapper);
99 static int vss_handle_handshake(struct hv_vss_msg *vss_msg)
101 u32 our_ver = VSS_OP_REGISTER1;
103 switch (vss_msg->vss_hdr.operation) {
104 case VSS_OP_REGISTER:
105 /* Daemon doesn't expect us to reply */
106 dm_reg_value = VSS_OP_REGISTER;
107 break;
108 case VSS_OP_REGISTER1:
109 /* Daemon expects us to reply with our own version*/
110 if (hvutil_transport_send(hvt, &our_ver, sizeof(our_ver)))
111 return -EFAULT;
112 dm_reg_value = VSS_OP_REGISTER1;
113 break;
114 default:
115 return -EINVAL;
117 vss_transaction.state = HVUTIL_READY;
118 pr_debug("VSS: userspace daemon ver. %d registered\n", dm_reg_value);
119 return 0;
122 static int vss_on_msg(void *msg, int len)
124 struct hv_vss_msg *vss_msg = (struct hv_vss_msg *)msg;
126 if (len != sizeof(*vss_msg))
127 return -EINVAL;
129 if (vss_msg->vss_hdr.operation == VSS_OP_REGISTER ||
130 vss_msg->vss_hdr.operation == VSS_OP_REGISTER1) {
132 * Don't process registration messages if we're in the middle
133 * of a transaction processing.
135 if (vss_transaction.state > HVUTIL_READY)
136 return -EINVAL;
137 return vss_handle_handshake(vss_msg);
138 } else if (vss_transaction.state == HVUTIL_USERSPACE_REQ) {
139 vss_transaction.state = HVUTIL_USERSPACE_RECV;
140 if (cancel_delayed_work_sync(&vss_timeout_work)) {
141 vss_respond_to_host(vss_msg->error);
142 /* Transaction is finished, reset the state. */
143 hv_poll_channel(vss_transaction.recv_channel,
144 vss_poll_wrapper);
146 } else {
147 /* This is a spurious call! */
148 pr_warn("VSS: Transaction not active\n");
149 return -EINVAL;
151 return 0;
155 static void vss_send_op(struct work_struct *dummy)
157 int op = vss_transaction.msg->vss_hdr.operation;
158 int rc;
159 struct hv_vss_msg *vss_msg;
161 /* The transaction state is wrong. */
162 if (vss_transaction.state != HVUTIL_HOSTMSG_RECEIVED)
163 return;
165 vss_msg = kzalloc(sizeof(*vss_msg), GFP_KERNEL);
166 if (!vss_msg)
167 return;
169 vss_msg->vss_hdr.operation = op;
171 vss_transaction.state = HVUTIL_USERSPACE_REQ;
172 rc = hvutil_transport_send(hvt, vss_msg, sizeof(*vss_msg));
173 if (rc) {
174 pr_warn("VSS: failed to communicate to the daemon: %d\n", rc);
175 if (cancel_delayed_work_sync(&vss_timeout_work)) {
176 vss_respond_to_host(HV_E_FAIL);
177 vss_transaction.state = HVUTIL_READY;
181 kfree(vss_msg);
183 return;
187 * Send a response back to the host.
190 static void
191 vss_respond_to_host(int error)
193 struct icmsg_hdr *icmsghdrp;
194 u32 buf_len;
195 struct vmbus_channel *channel;
196 u64 req_id;
199 * Copy the global state for completing the transaction. Note that
200 * only one transaction can be active at a time.
203 buf_len = vss_transaction.recv_len;
204 channel = vss_transaction.recv_channel;
205 req_id = vss_transaction.recv_req_id;
207 icmsghdrp = (struct icmsg_hdr *)
208 &recv_buffer[sizeof(struct vmbuspipe_hdr)];
210 if (channel->onchannel_callback == NULL)
212 * We have raced with util driver being unloaded;
213 * silently return.
215 return;
217 icmsghdrp->status = error;
219 icmsghdrp->icflags = ICMSGHDRFLAG_TRANSACTION | ICMSGHDRFLAG_RESPONSE;
221 vmbus_sendpacket(channel, recv_buffer, buf_len, req_id,
222 VM_PKT_DATA_INBAND, 0);
227 * This callback is invoked when we get a VSS message from the host.
228 * The host ensures that only one VSS transaction can be active at a time.
231 void hv_vss_onchannelcallback(void *context)
233 struct vmbus_channel *channel = context;
234 u32 recvlen;
235 u64 requestid;
236 struct hv_vss_msg *vss_msg;
239 struct icmsg_hdr *icmsghdrp;
240 struct icmsg_negotiate *negop = NULL;
242 if (vss_transaction.state > HVUTIL_READY)
243 return;
245 vmbus_recvpacket(channel, recv_buffer, PAGE_SIZE * 2, &recvlen,
246 &requestid);
248 if (recvlen > 0) {
249 icmsghdrp = (struct icmsg_hdr *)&recv_buffer[
250 sizeof(struct vmbuspipe_hdr)];
252 if (icmsghdrp->icmsgtype == ICMSGTYPE_NEGOTIATE) {
253 vmbus_prep_negotiate_resp(icmsghdrp, negop,
254 recv_buffer, UTIL_FW_VERSION,
255 VSS_VERSION);
256 } else {
257 vss_msg = (struct hv_vss_msg *)&recv_buffer[
258 sizeof(struct vmbuspipe_hdr) +
259 sizeof(struct icmsg_hdr)];
262 * Stash away this global state for completing the
263 * transaction; note transactions are serialized.
266 vss_transaction.recv_len = recvlen;
267 vss_transaction.recv_channel = channel;
268 vss_transaction.recv_req_id = requestid;
269 vss_transaction.msg = (struct hv_vss_msg *)vss_msg;
271 switch (vss_msg->vss_hdr.operation) {
273 * Initiate a "freeze/thaw"
274 * operation in the guest.
275 * We respond to the host once
276 * the operation is complete.
278 * We send the message to the
279 * user space daemon and the
280 * operation is performed in
281 * the daemon.
283 case VSS_OP_FREEZE:
284 case VSS_OP_THAW:
285 if (vss_transaction.state < HVUTIL_READY) {
286 /* Userspace is not registered yet */
287 vss_respond_to_host(HV_E_FAIL);
288 return;
290 vss_transaction.state = HVUTIL_HOSTMSG_RECEIVED;
291 schedule_work(&vss_send_op_work);
292 schedule_delayed_work(&vss_timeout_work,
293 VSS_USERSPACE_TIMEOUT);
294 return;
296 case VSS_OP_HOT_BACKUP:
297 vss_msg->vss_cf.flags =
298 VSS_HBU_NO_AUTO_RECOVERY;
299 vss_respond_to_host(0);
300 return;
302 case VSS_OP_GET_DM_INFO:
303 vss_msg->dm_info.flags = 0;
304 vss_respond_to_host(0);
305 return;
307 default:
308 vss_respond_to_host(0);
309 return;
315 icmsghdrp->icflags = ICMSGHDRFLAG_TRANSACTION
316 | ICMSGHDRFLAG_RESPONSE;
318 vmbus_sendpacket(channel, recv_buffer,
319 recvlen, requestid,
320 VM_PKT_DATA_INBAND, 0);
325 static void vss_on_reset(void)
327 if (cancel_delayed_work_sync(&vss_timeout_work))
328 vss_respond_to_host(HV_E_FAIL);
329 vss_transaction.state = HVUTIL_DEVICE_INIT;
330 complete(&release_event);
334 hv_vss_init(struct hv_util_service *srv)
336 init_completion(&release_event);
337 if (vmbus_proto_version < VERSION_WIN8_1) {
338 pr_warn("Integration service 'Backup (volume snapshot)'"
339 " not supported on this host version.\n");
340 return -ENOTSUPP;
342 recv_buffer = srv->recv_buffer;
345 * When this driver loads, the user level daemon that
346 * processes the host requests may not yet be running.
347 * Defer processing channel callbacks until the daemon
348 * has registered.
350 vss_transaction.state = HVUTIL_DEVICE_INIT;
352 hvt = hvutil_transport_init(vss_devname, CN_VSS_IDX, CN_VSS_VAL,
353 vss_on_msg, vss_on_reset);
354 if (!hvt)
355 return -EFAULT;
357 return 0;
360 void hv_vss_deinit(void)
362 vss_transaction.state = HVUTIL_DEVICE_DYING;
363 cancel_delayed_work_sync(&vss_timeout_work);
364 cancel_work_sync(&vss_send_op_work);
365 hvutil_transport_destroy(hvt);
366 wait_for_completion(&release_event);