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9bad2a6b PB |
1 | /* |
2 | * Persistent reservation manager that talks to qemu-pr-helper | |
3 | * | |
4 | * Copyright (c) 2017 Red Hat, Inc. | |
5 | * | |
6 | * Author: Paolo Bonzini <pbonzini@redhat.com> | |
7 | * | |
8 | * This code is licensed under the LGPL v2.1 or later. | |
9 | * | |
10 | */ | |
11 | ||
12 | #include "qemu/osdep.h" | |
13 | #include "qapi/error.h" | |
14 | #include "scsi/constants.h" | |
15 | #include "scsi/pr-manager.h" | |
16 | #include "scsi/utils.h" | |
17 | #include "io/channel.h" | |
18 | #include "io/channel-socket.h" | |
19 | #include "pr-helper.h" | |
20 | ||
21 | #include <scsi/sg.h> | |
22 | ||
23 | #define PR_MAX_RECONNECT_ATTEMPTS 5 | |
24 | ||
25 | #define TYPE_PR_MANAGER_HELPER "pr-manager-helper" | |
26 | ||
27 | #define PR_MANAGER_HELPER(obj) \ | |
28 | OBJECT_CHECK(PRManagerHelper, (obj), \ | |
29 | TYPE_PR_MANAGER_HELPER) | |
30 | ||
31 | typedef struct PRManagerHelper { | |
32 | /* <private> */ | |
33 | PRManager parent; | |
34 | ||
35 | char *path; | |
36 | ||
37 | QemuMutex lock; | |
38 | QIOChannel *ioc; | |
39 | } PRManagerHelper; | |
40 | ||
41 | /* Called with lock held. */ | |
42 | static int pr_manager_helper_read(PRManagerHelper *pr_mgr, | |
43 | void *buf, int sz, Error **errp) | |
44 | { | |
45 | ssize_t r = qio_channel_read_all(pr_mgr->ioc, buf, sz, errp); | |
46 | ||
47 | if (r < 0) { | |
48 | object_unref(OBJECT(pr_mgr->ioc)); | |
49 | pr_mgr->ioc = NULL; | |
50 | return -EINVAL; | |
51 | } | |
52 | ||
53 | return 0; | |
54 | } | |
55 | ||
56 | /* Called with lock held. */ | |
57 | static int pr_manager_helper_write(PRManagerHelper *pr_mgr, | |
58 | int fd, | |
59 | const void *buf, int sz, Error **errp) | |
60 | { | |
61 | size_t nfds = (fd != -1); | |
62 | while (sz > 0) { | |
63 | struct iovec iov; | |
64 | ssize_t n_written; | |
65 | ||
66 | iov.iov_base = (void *)buf; | |
67 | iov.iov_len = sz; | |
68 | n_written = qio_channel_writev_full(QIO_CHANNEL(pr_mgr->ioc), &iov, 1, | |
69 | nfds ? &fd : NULL, nfds, errp); | |
70 | ||
71 | if (n_written <= 0) { | |
72 | assert(n_written != QIO_CHANNEL_ERR_BLOCK); | |
73 | object_unref(OBJECT(pr_mgr->ioc)); | |
aad10040 | 74 | pr_mgr->ioc = NULL; |
9bad2a6b PB |
75 | return n_written < 0 ? -EINVAL : 0; |
76 | } | |
77 | ||
78 | nfds = 0; | |
79 | buf += n_written; | |
80 | sz -= n_written; | |
81 | } | |
82 | ||
83 | return 0; | |
84 | } | |
85 | ||
86 | /* Called with lock held. */ | |
87 | static int pr_manager_helper_initialize(PRManagerHelper *pr_mgr, | |
88 | Error **errp) | |
89 | { | |
90 | char *path = g_strdup(pr_mgr->path); | |
91 | SocketAddress saddr = { | |
92 | .type = SOCKET_ADDRESS_TYPE_UNIX, | |
93 | .u.q_unix.path = path | |
94 | }; | |
95 | QIOChannelSocket *sioc = qio_channel_socket_new(); | |
96 | Error *local_err = NULL; | |
97 | ||
98 | uint32_t flags; | |
99 | int r; | |
100 | ||
101 | assert(!pr_mgr->ioc); | |
102 | qio_channel_set_name(QIO_CHANNEL(sioc), "pr-manager-helper"); | |
103 | qio_channel_socket_connect_sync(sioc, | |
104 | &saddr, | |
105 | &local_err); | |
106 | g_free(path); | |
107 | if (local_err) { | |
108 | object_unref(OBJECT(sioc)); | |
109 | error_propagate(errp, local_err); | |
110 | return -ENOTCONN; | |
111 | } | |
112 | ||
113 | qio_channel_set_delay(QIO_CHANNEL(sioc), false); | |
114 | pr_mgr->ioc = QIO_CHANNEL(sioc); | |
115 | ||
116 | /* A simple feature negotation protocol, even though there is | |
117 | * no optional feature right now. | |
118 | */ | |
119 | r = pr_manager_helper_read(pr_mgr, &flags, sizeof(flags), errp); | |
120 | if (r < 0) { | |
121 | goto out_close; | |
122 | } | |
123 | ||
124 | flags = 0; | |
125 | r = pr_manager_helper_write(pr_mgr, -1, &flags, sizeof(flags), errp); | |
126 | if (r < 0) { | |
127 | goto out_close; | |
128 | } | |
129 | ||
130 | return 0; | |
131 | ||
132 | out_close: | |
133 | object_unref(OBJECT(pr_mgr->ioc)); | |
134 | pr_mgr->ioc = NULL; | |
135 | return r; | |
136 | } | |
137 | ||
138 | static int pr_manager_helper_run(PRManager *p, | |
139 | int fd, struct sg_io_hdr *io_hdr) | |
140 | { | |
141 | PRManagerHelper *pr_mgr = PR_MANAGER_HELPER(p); | |
142 | ||
143 | uint32_t len; | |
144 | PRHelperResponse resp; | |
145 | int ret; | |
146 | int expected_dir; | |
147 | int attempts; | |
148 | uint8_t cdb[PR_HELPER_CDB_SIZE] = { 0 }; | |
149 | ||
150 | if (!io_hdr->cmd_len || io_hdr->cmd_len > PR_HELPER_CDB_SIZE) { | |
151 | return -EINVAL; | |
152 | } | |
153 | ||
154 | memcpy(cdb, io_hdr->cmdp, io_hdr->cmd_len); | |
155 | assert(cdb[0] == PERSISTENT_RESERVE_OUT || cdb[0] == PERSISTENT_RESERVE_IN); | |
156 | expected_dir = | |
157 | (cdb[0] == PERSISTENT_RESERVE_OUT ? SG_DXFER_TO_DEV : SG_DXFER_FROM_DEV); | |
158 | if (io_hdr->dxfer_direction != expected_dir) { | |
159 | return -EINVAL; | |
160 | } | |
161 | ||
162 | len = scsi_cdb_xfer(cdb); | |
163 | if (io_hdr->dxfer_len < len || len > PR_HELPER_DATA_SIZE) { | |
164 | return -EINVAL; | |
165 | } | |
166 | ||
167 | qemu_mutex_lock(&pr_mgr->lock); | |
168 | ||
169 | /* Try to reconnect while sending the CDB. */ | |
170 | for (attempts = 0; attempts < PR_MAX_RECONNECT_ATTEMPTS; attempts++) { | |
171 | if (!pr_mgr->ioc) { | |
172 | ret = pr_manager_helper_initialize(pr_mgr, NULL); | |
173 | if (ret < 0) { | |
174 | qemu_mutex_unlock(&pr_mgr->lock); | |
175 | g_usleep(G_USEC_PER_SEC); | |
176 | qemu_mutex_lock(&pr_mgr->lock); | |
177 | continue; | |
178 | } | |
179 | } | |
180 | ||
181 | ret = pr_manager_helper_write(pr_mgr, fd, cdb, ARRAY_SIZE(cdb), NULL); | |
182 | if (ret >= 0) { | |
183 | break; | |
184 | } | |
185 | } | |
186 | if (ret < 0) { | |
187 | goto out; | |
188 | } | |
189 | ||
190 | /* After sending the CDB, any communications failure causes the | |
191 | * command to fail. The failure is transient, retrying the command | |
192 | * will invoke pr_manager_helper_initialize again. | |
193 | */ | |
194 | if (expected_dir == SG_DXFER_TO_DEV) { | |
195 | io_hdr->resid = io_hdr->dxfer_len - len; | |
196 | ret = pr_manager_helper_write(pr_mgr, -1, io_hdr->dxferp, len, NULL); | |
197 | if (ret < 0) { | |
198 | goto out; | |
199 | } | |
200 | } | |
201 | ret = pr_manager_helper_read(pr_mgr, &resp, sizeof(resp), NULL); | |
202 | if (ret < 0) { | |
203 | goto out; | |
204 | } | |
205 | ||
206 | resp.result = be32_to_cpu(resp.result); | |
207 | resp.sz = be32_to_cpu(resp.sz); | |
208 | if (io_hdr->dxfer_direction == SG_DXFER_FROM_DEV) { | |
209 | assert(resp.sz <= io_hdr->dxfer_len); | |
210 | ret = pr_manager_helper_read(pr_mgr, io_hdr->dxferp, resp.sz, NULL); | |
211 | if (ret < 0) { | |
212 | goto out; | |
213 | } | |
214 | io_hdr->resid = io_hdr->dxfer_len - resp.sz; | |
215 | } else { | |
216 | assert(resp.sz == 0); | |
217 | } | |
218 | ||
219 | io_hdr->status = resp.result; | |
220 | if (resp.result == CHECK_CONDITION) { | |
221 | io_hdr->driver_status = SG_ERR_DRIVER_SENSE; | |
222 | io_hdr->sb_len_wr = MIN(io_hdr->mx_sb_len, PR_HELPER_SENSE_SIZE); | |
223 | memcpy(io_hdr->sbp, resp.sense, io_hdr->sb_len_wr); | |
224 | } | |
225 | ||
226 | out: | |
227 | if (ret < 0) { | |
228 | int sense_len = scsi_build_sense(io_hdr->sbp, | |
229 | SENSE_CODE(LUN_COMM_FAILURE)); | |
230 | io_hdr->driver_status = SG_ERR_DRIVER_SENSE; | |
231 | io_hdr->sb_len_wr = MIN(io_hdr->mx_sb_len, sense_len); | |
232 | io_hdr->status = CHECK_CONDITION; | |
233 | } | |
234 | qemu_mutex_unlock(&pr_mgr->lock); | |
235 | return ret; | |
236 | } | |
237 | ||
5f640894 PB |
238 | static bool pr_manager_helper_is_connected(PRManager *p) |
239 | { | |
240 | PRManagerHelper *pr_mgr = PR_MANAGER_HELPER(p); | |
241 | bool result; | |
242 | ||
243 | qemu_mutex_lock(&pr_mgr->lock); | |
244 | result = (pr_mgr->ioc != NULL); | |
245 | qemu_mutex_unlock(&pr_mgr->lock); | |
246 | ||
247 | return result; | |
248 | } | |
249 | ||
9bad2a6b PB |
250 | static void pr_manager_helper_complete(UserCreatable *uc, Error **errp) |
251 | { | |
252 | PRManagerHelper *pr_mgr = PR_MANAGER_HELPER(uc); | |
253 | ||
254 | qemu_mutex_lock(&pr_mgr->lock); | |
255 | pr_manager_helper_initialize(pr_mgr, errp); | |
256 | qemu_mutex_unlock(&pr_mgr->lock); | |
257 | } | |
258 | ||
259 | static char *get_path(Object *obj, Error **errp) | |
260 | { | |
261 | PRManagerHelper *pr_mgr = PR_MANAGER_HELPER(obj); | |
262 | ||
263 | return g_strdup(pr_mgr->path); | |
264 | } | |
265 | ||
266 | static void set_path(Object *obj, const char *str, Error **errp) | |
267 | { | |
268 | PRManagerHelper *pr_mgr = PR_MANAGER_HELPER(obj); | |
269 | ||
270 | g_free(pr_mgr->path); | |
271 | pr_mgr->path = g_strdup(str); | |
272 | } | |
273 | ||
274 | static void pr_manager_helper_instance_finalize(Object *obj) | |
275 | { | |
276 | PRManagerHelper *pr_mgr = PR_MANAGER_HELPER(obj); | |
277 | ||
278 | object_unref(OBJECT(pr_mgr->ioc)); | |
279 | qemu_mutex_destroy(&pr_mgr->lock); | |
280 | } | |
281 | ||
282 | static void pr_manager_helper_instance_init(Object *obj) | |
283 | { | |
284 | PRManagerHelper *pr_mgr = PR_MANAGER_HELPER(obj); | |
285 | ||
286 | qemu_mutex_init(&pr_mgr->lock); | |
287 | } | |
288 | ||
289 | static void pr_manager_helper_class_init(ObjectClass *klass, | |
290 | void *class_data G_GNUC_UNUSED) | |
291 | { | |
292 | PRManagerClass *prmgr_klass = PR_MANAGER_CLASS(klass); | |
293 | UserCreatableClass *uc_klass = USER_CREATABLE_CLASS(klass); | |
294 | ||
295 | object_class_property_add_str(klass, "path", get_path, set_path, | |
296 | &error_abort); | |
297 | uc_klass->complete = pr_manager_helper_complete; | |
298 | prmgr_klass->run = pr_manager_helper_run; | |
5f640894 | 299 | prmgr_klass->is_connected = pr_manager_helper_is_connected; |
9bad2a6b PB |
300 | } |
301 | ||
302 | static const TypeInfo pr_manager_helper_info = { | |
303 | .parent = TYPE_PR_MANAGER, | |
304 | .name = TYPE_PR_MANAGER_HELPER, | |
305 | .instance_size = sizeof(PRManagerHelper), | |
306 | .instance_init = pr_manager_helper_instance_init, | |
307 | .instance_finalize = pr_manager_helper_instance_finalize, | |
308 | .class_init = pr_manager_helper_class_init, | |
309 | }; | |
310 | ||
311 | static void pr_manager_helper_register_types(void) | |
312 | { | |
313 | type_register_static(&pr_manager_helper_info); | |
314 | } | |
315 | ||
316 | type_init(pr_manager_helper_register_types); |