Commit | Line | Data |
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b411b363 PR |
1 | /* |
2 | drbd_req.h | |
3 | ||
4 | This file is part of DRBD by Philipp Reisner and Lars Ellenberg. | |
5 | ||
6 | Copyright (C) 2006-2008, LINBIT Information Technologies GmbH. | |
7 | Copyright (C) 2006-2008, Lars Ellenberg <lars.ellenberg@linbit.com>. | |
8 | Copyright (C) 2006-2008, Philipp Reisner <philipp.reisner@linbit.com>. | |
9 | ||
10 | DRBD is free software; you can redistribute it and/or modify | |
11 | it under the terms of the GNU General Public License as published by | |
12 | the Free Software Foundation; either version 2, or (at your option) | |
13 | any later version. | |
14 | ||
15 | DRBD is distributed in the hope that it will be useful, | |
16 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
17 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
18 | GNU General Public License for more details. | |
19 | ||
20 | You should have received a copy of the GNU General Public License | |
21 | along with drbd; see the file COPYING. If not, write to | |
22 | the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. | |
23 | */ | |
24 | ||
25 | #ifndef _DRBD_REQ_H | |
26 | #define _DRBD_REQ_H | |
27 | ||
b411b363 PR |
28 | #include <linux/module.h> |
29 | ||
30 | #include <linux/slab.h> | |
31 | #include <linux/drbd.h> | |
32 | #include "drbd_int.h" | |
b411b363 PR |
33 | |
34 | /* The request callbacks will be called in irq context by the IDE drivers, | |
35 | and in Softirqs/Tasklets/BH context by the SCSI drivers, | |
36 | and by the receiver and worker in kernel-thread context. | |
37 | Try to get the locking right :) */ | |
38 | ||
39 | /* | |
40 | * Objects of type struct drbd_request do only exist on a R_PRIMARY node, and are | |
41 | * associated with IO requests originating from the block layer above us. | |
42 | * | |
43 | * There are quite a few things that may happen to a drbd request | |
44 | * during its lifetime. | |
45 | * | |
46 | * It will be created. | |
47 | * It will be marked with the intention to be | |
48 | * submitted to local disk and/or | |
49 | * send via the network. | |
50 | * | |
51 | * It has to be placed on the transfer log and other housekeeping lists, | |
52 | * In case we have a network connection. | |
53 | * | |
54 | * It may be identified as a concurrent (write) request | |
55 | * and be handled accordingly. | |
56 | * | |
57 | * It may me handed over to the local disk subsystem. | |
58 | * It may be completed by the local disk subsystem, | |
3ad2f3fb | 59 | * either successfully or with io-error. |
b411b363 PR |
60 | * In case it is a READ request, and it failed locally, |
61 | * it may be retried remotely. | |
62 | * | |
63 | * It may be queued for sending. | |
64 | * It may be handed over to the network stack, | |
65 | * which may fail. | |
66 | * It may be acknowledged by the "peer" according to the wire_protocol in use. | |
67 | * this may be a negative ack. | |
68 | * It may receive a faked ack when the network connection is lost and the | |
69 | * transfer log is cleaned up. | |
70 | * Sending may be canceled due to network connection loss. | |
71 | * When it finally has outlived its time, | |
72 | * corresponding dirty bits in the resync-bitmap may be cleared or set, | |
73 | * it will be destroyed, | |
74 | * and completion will be signalled to the originator, | |
75 | * with or without "success". | |
76 | */ | |
77 | ||
78 | enum drbd_req_event { | |
8554df1c AG |
79 | CREATED, |
80 | TO_BE_SENT, | |
81 | TO_BE_SUBMITTED, | |
b411b363 PR |
82 | |
83 | /* XXX yes, now I am inconsistent... | |
73a01a18 | 84 | * these are not "events" but "actions" |
b411b363 | 85 | * oh, well... */ |
8554df1c AG |
86 | QUEUE_FOR_NET_WRITE, |
87 | QUEUE_FOR_NET_READ, | |
88 | QUEUE_FOR_SEND_OOS, | |
89 | ||
7074e4a7 LE |
90 | /* An empty flush is queued as P_BARRIER, |
91 | * which will cause it to complete "successfully", | |
92 | * even if the local disk flush failed. | |
93 | * | |
94 | * Just like "real" requests, empty flushes (blkdev_issue_flush()) will | |
95 | * only see an error if neither local nor remote data is reachable. */ | |
96 | QUEUE_AS_DRBD_BARRIER, | |
97 | ||
8554df1c AG |
98 | SEND_CANCELED, |
99 | SEND_FAILED, | |
100 | HANDED_OVER_TO_NETWORK, | |
101 | OOS_HANDED_TO_NETWORK, | |
102 | CONNECTION_LOST_WHILE_PENDING, | |
103 | READ_RETRY_REMOTE_CANCELED, | |
104 | RECV_ACKED_BY_PEER, | |
105 | WRITE_ACKED_BY_PEER, | |
106 | WRITE_ACKED_BY_PEER_AND_SIS, /* and set_in_sync */ | |
d4dabbe2 | 107 | CONFLICT_RESOLVED, |
7be8da07 | 108 | POSTPONE_WRITE, |
8554df1c AG |
109 | NEG_ACKED, |
110 | BARRIER_ACKED, /* in protocol A and B */ | |
111 | DATA_RECEIVED, /* (remote read) */ | |
112 | ||
2f632aeb | 113 | COMPLETED_OK, |
8554df1c AG |
114 | READ_COMPLETED_WITH_ERROR, |
115 | READ_AHEAD_COMPLETED_WITH_ERROR, | |
116 | WRITE_COMPLETED_WITH_ERROR, | |
2f632aeb LE |
117 | DISCARD_COMPLETED_NOTSUPP, |
118 | DISCARD_COMPLETED_WITH_ERROR, | |
119 | ||
cdfda633 | 120 | ABORT_DISK_IO, |
8554df1c AG |
121 | RESEND, |
122 | FAIL_FROZEN_DISK_IO, | |
123 | RESTART_FROZEN_DISK_IO, | |
124 | NOTHING, | |
b411b363 PR |
125 | }; |
126 | ||
127 | /* encoding of request states for now. we don't actually need that many bits. | |
128 | * we don't need to do atomic bit operations either, since most of the time we | |
129 | * need to look at the connection state and/or manipulate some lists at the | |
130 | * same time, so we should hold the request lock anyways. | |
131 | */ | |
132 | enum drbd_req_state_bits { | |
cdfda633 PR |
133 | /* 3210 |
134 | * 0000: no local possible | |
135 | * 0001: to be submitted | |
b411b363 | 136 | * UNUSED, we could map: 011: submitted, completion still pending |
cdfda633 PR |
137 | * 0110: completed ok |
138 | * 0010: completed with error | |
139 | * 1001: Aborted (before completion) | |
140 | * 1x10: Aborted and completed -> free | |
b411b363 PR |
141 | */ |
142 | __RQ_LOCAL_PENDING, | |
143 | __RQ_LOCAL_COMPLETED, | |
144 | __RQ_LOCAL_OK, | |
cdfda633 | 145 | __RQ_LOCAL_ABORTED, |
b411b363 | 146 | |
cdfda633 | 147 | /* 87654 |
b411b363 PR |
148 | * 00000: no network possible |
149 | * 00001: to be send | |
150 | * 00011: to be send, on worker queue | |
151 | * 00101: sent, expecting recv_ack (B) or write_ack (C) | |
152 | * 11101: sent, | |
153 | * recv_ack (B) or implicit "ack" (A), | |
154 | * still waiting for the barrier ack. | |
155 | * master_bio may already be completed and invalidated. | |
8554df1c AG |
156 | * 11100: write acked (C), |
157 | * data received (for remote read, any protocol) | |
b411b363 PR |
158 | * or finally the barrier ack has arrived (B,A)... |
159 | * request can be freed | |
160 | * 01100: neg-acked (write, protocol C) | |
161 | * or neg-d-acked (read, any protocol) | |
162 | * or killed from the transfer log | |
163 | * during cleanup after connection loss | |
164 | * request can be freed | |
165 | * 01000: canceled or send failed... | |
166 | * request can be freed | |
167 | */ | |
168 | ||
169 | /* if "SENT" is not set, yet, this can still fail or be canceled. | |
170 | * if "SENT" is set already, we still wait for an Ack packet. | |
171 | * when cleared, the master_bio may be completed. | |
172 | * in (B,A) the request object may still linger on the transaction log | |
173 | * until the corresponding barrier ack comes in */ | |
174 | __RQ_NET_PENDING, | |
175 | ||
176 | /* If it is QUEUED, and it is a WRITE, it is also registered in the | |
177 | * transfer log. Currently we need this flag to avoid conflicts between | |
178 | * worker canceling the request and tl_clear_barrier killing it from | |
179 | * transfer log. We should restructure the code so this conflict does | |
180 | * no longer occur. */ | |
181 | __RQ_NET_QUEUED, | |
182 | ||
183 | /* well, actually only "handed over to the network stack". | |
184 | * | |
185 | * TODO can potentially be dropped because of the similar meaning | |
186 | * of RQ_NET_SENT and ~RQ_NET_QUEUED. | |
187 | * however it is not exactly the same. before we drop it | |
188 | * we must ensure that we can tell a request with network part | |
189 | * from a request without, regardless of what happens to it. */ | |
190 | __RQ_NET_SENT, | |
191 | ||
192 | /* when set, the request may be freed (if RQ_NET_QUEUED is clear). | |
193 | * basically this means the corresponding P_BARRIER_ACK was received */ | |
194 | __RQ_NET_DONE, | |
195 | ||
196 | /* whether or not we know (C) or pretend (B,A) that the write | |
197 | * was successfully written on the peer. | |
198 | */ | |
199 | __RQ_NET_OK, | |
200 | ||
201 | /* peer called drbd_set_in_sync() for this write */ | |
202 | __RQ_NET_SIS, | |
203 | ||
204 | /* keep this last, its for the RQ_NET_MASK */ | |
205 | __RQ_NET_MAX, | |
288f422e PR |
206 | |
207 | /* Set when this is a write, clear for a read */ | |
208 | __RQ_WRITE, | |
0778286a PR |
209 | |
210 | /* Should call drbd_al_complete_io() for this request... */ | |
211 | __RQ_IN_ACT_LOG, | |
7be8da07 AG |
212 | |
213 | /* The peer has sent a retry ACK */ | |
214 | __RQ_POSTPONED, | |
303d1448 | 215 | |
a0d856df LE |
216 | /* would have been completed, |
217 | * but was not, because of drbd_suspended() */ | |
218 | __RQ_COMPLETION_SUSP, | |
219 | ||
303d1448 PR |
220 | /* We expect a receive ACK (wire proto B) */ |
221 | __RQ_EXP_RECEIVE_ACK, | |
222 | ||
223 | /* We expect a write ACK (wite proto C) */ | |
224 | __RQ_EXP_WRITE_ACK, | |
a0d856df LE |
225 | |
226 | /* waiting for a barrier ack, did an extra kref_get */ | |
227 | __RQ_EXP_BARR_ACK, | |
b411b363 PR |
228 | }; |
229 | ||
230 | #define RQ_LOCAL_PENDING (1UL << __RQ_LOCAL_PENDING) | |
231 | #define RQ_LOCAL_COMPLETED (1UL << __RQ_LOCAL_COMPLETED) | |
232 | #define RQ_LOCAL_OK (1UL << __RQ_LOCAL_OK) | |
cdfda633 | 233 | #define RQ_LOCAL_ABORTED (1UL << __RQ_LOCAL_ABORTED) |
b411b363 | 234 | |
cdfda633 | 235 | #define RQ_LOCAL_MASK ((RQ_LOCAL_ABORTED << 1)-1) |
b411b363 PR |
236 | |
237 | #define RQ_NET_PENDING (1UL << __RQ_NET_PENDING) | |
238 | #define RQ_NET_QUEUED (1UL << __RQ_NET_QUEUED) | |
239 | #define RQ_NET_SENT (1UL << __RQ_NET_SENT) | |
240 | #define RQ_NET_DONE (1UL << __RQ_NET_DONE) | |
241 | #define RQ_NET_OK (1UL << __RQ_NET_OK) | |
242 | #define RQ_NET_SIS (1UL << __RQ_NET_SIS) | |
243 | ||
244 | /* 0x1f8 */ | |
245 | #define RQ_NET_MASK (((1UL << __RQ_NET_MAX)-1) & ~RQ_LOCAL_MASK) | |
246 | ||
288f422e | 247 | #define RQ_WRITE (1UL << __RQ_WRITE) |
0778286a | 248 | #define RQ_IN_ACT_LOG (1UL << __RQ_IN_ACT_LOG) |
7be8da07 | 249 | #define RQ_POSTPONED (1UL << __RQ_POSTPONED) |
a0d856df | 250 | #define RQ_COMPLETION_SUSP (1UL << __RQ_COMPLETION_SUSP) |
303d1448 PR |
251 | #define RQ_EXP_RECEIVE_ACK (1UL << __RQ_EXP_RECEIVE_ACK) |
252 | #define RQ_EXP_WRITE_ACK (1UL << __RQ_EXP_WRITE_ACK) | |
a0d856df | 253 | #define RQ_EXP_BARR_ACK (1UL << __RQ_EXP_BARR_ACK) |
288f422e | 254 | |
11b58e73 PR |
255 | /* For waking up the frozen transfer log mod_req() has to return if the request |
256 | should be counted in the epoch object*/ | |
f497609e AG |
257 | #define MR_WRITE 1 |
258 | #define MR_READ 2 | |
11b58e73 | 259 | |
5ba82308 PR |
260 | static inline void drbd_req_make_private_bio(struct drbd_request *req, struct bio *bio_src) |
261 | { | |
262 | struct bio *bio; | |
263 | bio = bio_clone(bio_src, GFP_NOIO); /* XXX cannot fail?? */ | |
264 | ||
265 | req->private_bio = bio; | |
266 | ||
267 | bio->bi_private = req; | |
fcefa62e | 268 | bio->bi_end_io = drbd_request_endio; |
5ba82308 PR |
269 | bio->bi_next = NULL; |
270 | } | |
271 | ||
b411b363 PR |
272 | /* Short lived temporary struct on the stack. |
273 | * We could squirrel the error to be returned into | |
4f024f37 | 274 | * bio->bi_iter.bi_size, or similar. But that would be too ugly. */ |
b411b363 PR |
275 | struct bio_and_error { |
276 | struct bio *bio; | |
277 | int error; | |
278 | }; | |
279 | ||
bde89a9e | 280 | extern void start_new_tl_epoch(struct drbd_connection *connection); |
9a278a79 | 281 | extern void drbd_req_destroy(struct kref *kref); |
b411b363 PR |
282 | extern void _req_may_be_done(struct drbd_request *req, |
283 | struct bio_and_error *m); | |
2a80699f | 284 | extern int __req_mod(struct drbd_request *req, enum drbd_req_event what, |
b411b363 | 285 | struct bio_and_error *m); |
b30ab791 | 286 | extern void complete_master_bio(struct drbd_device *device, |
b411b363 | 287 | struct bio_and_error *m); |
7fde2be9 | 288 | extern void request_timer_fn(unsigned long data); |
bde89a9e AG |
289 | extern void tl_restart(struct drbd_connection *connection, enum drbd_req_event what); |
290 | extern void _tl_restart(struct drbd_connection *connection, enum drbd_req_event what); | |
8ce953aa | 291 | extern void tl_abort_disk_io(struct drbd_device *device); |
b411b363 | 292 | |
2312f0b3 | 293 | /* this is in drbd_main.c */ |
9d05e7c4 | 294 | extern void drbd_restart_request(struct drbd_request *req); |
2312f0b3 | 295 | |
b411b363 PR |
296 | /* use this if you don't want to deal with calling complete_master_bio() |
297 | * outside the spinlock, e.g. when walking some list on cleanup. */ | |
2a80699f | 298 | static inline int _req_mod(struct drbd_request *req, enum drbd_req_event what) |
b411b363 | 299 | { |
84b8c06b | 300 | struct drbd_device *device = req->device; |
b411b363 | 301 | struct bio_and_error m; |
2a80699f | 302 | int rv; |
b411b363 PR |
303 | |
304 | /* __req_mod possibly frees req, do not touch req after that! */ | |
2a80699f | 305 | rv = __req_mod(req, what, &m); |
b411b363 | 306 | if (m.bio) |
b30ab791 | 307 | complete_master_bio(device, &m); |
2a80699f PR |
308 | |
309 | return rv; | |
b411b363 PR |
310 | } |
311 | ||
759fbdfb PR |
312 | /* completion of master bio is outside of our spinlock. |
313 | * We still may or may not be inside some irqs disabled section | |
314 | * of the lower level driver completion callback, so we need to | |
315 | * spin_lock_irqsave here. */ | |
2a80699f | 316 | static inline int req_mod(struct drbd_request *req, |
b411b363 PR |
317 | enum drbd_req_event what) |
318 | { | |
759fbdfb | 319 | unsigned long flags; |
84b8c06b | 320 | struct drbd_device *device = req->device; |
b411b363 | 321 | struct bio_and_error m; |
2a80699f PR |
322 | int rv; |
323 | ||
0500813f | 324 | spin_lock_irqsave(&device->resource->req_lock, flags); |
2a80699f | 325 | rv = __req_mod(req, what, &m); |
0500813f | 326 | spin_unlock_irqrestore(&device->resource->req_lock, flags); |
b411b363 PR |
327 | |
328 | if (m.bio) | |
b30ab791 | 329 | complete_master_bio(device, &m); |
2a80699f PR |
330 | |
331 | return rv; | |
b411b363 | 332 | } |
6a35c45f | 333 | |
da9fbc27 | 334 | static inline bool drbd_should_do_remote(union drbd_dev_state s) |
6a35c45f PR |
335 | { |
336 | return s.pdsk == D_UP_TO_DATE || | |
337 | (s.pdsk >= D_INCONSISTENT && | |
338 | s.conn >= C_WF_BITMAP_T && | |
339 | s.conn < C_AHEAD); | |
340 | /* Before proto 96 that was >= CONNECTED instead of >= C_WF_BITMAP_T. | |
341 | That is equivalent since before 96 IO was frozen in the C_WF_BITMAP* | |
342 | states. */ | |
343 | } | |
da9fbc27 | 344 | static inline bool drbd_should_send_out_of_sync(union drbd_dev_state s) |
6a35c45f PR |
345 | { |
346 | return s.conn == C_AHEAD || s.conn == C_WF_BITMAP_S; | |
347 | /* pdsk = D_INCONSISTENT as a consequence. Protocol 96 check not necessary | |
348 | since we enter state C_AHEAD only if proto >= 96 */ | |
349 | } | |
350 | ||
b411b363 | 351 | #endif |