1 | /* SPDX-License-Identifier: GPL-2.0-only */ |
2 | /* |
3 | drbd_req.h |
4 | |
5 | This file is part of DRBD by Philipp Reisner and Lars Ellenberg. |
6 | |
7 | Copyright (C) 2006-2008, LINBIT Information Technologies GmbH. |
8 | Copyright (C) 2006-2008, Lars Ellenberg <lars.ellenberg@linbit.com>. |
9 | Copyright (C) 2006-2008, Philipp Reisner <philipp.reisner@linbit.com>. |
10 | |
11 | */ |
12 | |
13 | #ifndef _DRBD_REQ_H |
14 | #define _DRBD_REQ_H |
15 | |
16 | #include <linux/module.h> |
17 | |
18 | #include <linux/slab.h> |
19 | #include <linux/drbd.h> |
20 | #include "drbd_int.h" |
21 | |
22 | /* The request callbacks will be called in irq context by the IDE drivers, |
23 | and in Softirqs/Tasklets/BH context by the SCSI drivers, |
24 | and by the receiver and worker in kernel-thread context. |
25 | Try to get the locking right :) */ |
26 | |
27 | /* |
28 | * Objects of type struct drbd_request do only exist on a R_PRIMARY node, and are |
29 | * associated with IO requests originating from the block layer above us. |
30 | * |
31 | * There are quite a few things that may happen to a drbd request |
32 | * during its lifetime. |
33 | * |
34 | * It will be created. |
35 | * It will be marked with the intention to be |
36 | * submitted to local disk and/or |
37 | * send via the network. |
38 | * |
39 | * It has to be placed on the transfer log and other housekeeping lists, |
40 | * In case we have a network connection. |
41 | * |
42 | * It may be identified as a concurrent (write) request |
43 | * and be handled accordingly. |
44 | * |
45 | * It may me handed over to the local disk subsystem. |
46 | * It may be completed by the local disk subsystem, |
47 | * either successfully or with io-error. |
48 | * In case it is a READ request, and it failed locally, |
49 | * it may be retried remotely. |
50 | * |
51 | * It may be queued for sending. |
52 | * It may be handed over to the network stack, |
53 | * which may fail. |
54 | * It may be acknowledged by the "peer" according to the wire_protocol in use. |
55 | * this may be a negative ack. |
56 | * It may receive a faked ack when the network connection is lost and the |
57 | * transfer log is cleaned up. |
58 | * Sending may be canceled due to network connection loss. |
59 | * When it finally has outlived its time, |
60 | * corresponding dirty bits in the resync-bitmap may be cleared or set, |
61 | * it will be destroyed, |
62 | * and completion will be signalled to the originator, |
63 | * with or without "success". |
64 | */ |
65 | |
66 | enum drbd_req_event { |
67 | CREATED, |
68 | TO_BE_SENT, |
69 | TO_BE_SUBMITTED, |
70 | |
71 | /* XXX yes, now I am inconsistent... |
72 | * these are not "events" but "actions" |
73 | * oh, well... */ |
74 | QUEUE_FOR_NET_WRITE, |
75 | QUEUE_FOR_NET_READ, |
76 | QUEUE_FOR_SEND_OOS, |
77 | |
78 | /* An empty flush is queued as P_BARRIER, |
79 | * which will cause it to complete "successfully", |
80 | * even if the local disk flush failed. |
81 | * |
82 | * Just like "real" requests, empty flushes (blkdev_issue_flush()) will |
83 | * only see an error if neither local nor remote data is reachable. */ |
84 | QUEUE_AS_DRBD_BARRIER, |
85 | |
86 | SEND_CANCELED, |
87 | SEND_FAILED, |
88 | HANDED_OVER_TO_NETWORK, |
89 | OOS_HANDED_TO_NETWORK, |
90 | CONNECTION_LOST_WHILE_PENDING, |
91 | READ_RETRY_REMOTE_CANCELED, |
92 | RECV_ACKED_BY_PEER, |
93 | WRITE_ACKED_BY_PEER, |
94 | WRITE_ACKED_BY_PEER_AND_SIS, /* and set_in_sync */ |
95 | CONFLICT_RESOLVED, |
96 | POSTPONE_WRITE, |
97 | NEG_ACKED, |
98 | BARRIER_ACKED, /* in protocol A and B */ |
99 | DATA_RECEIVED, /* (remote read) */ |
100 | |
101 | COMPLETED_OK, |
102 | READ_COMPLETED_WITH_ERROR, |
103 | READ_AHEAD_COMPLETED_WITH_ERROR, |
104 | WRITE_COMPLETED_WITH_ERROR, |
105 | DISCARD_COMPLETED_NOTSUPP, |
106 | DISCARD_COMPLETED_WITH_ERROR, |
107 | |
108 | ABORT_DISK_IO, |
109 | RESEND, |
110 | FAIL_FROZEN_DISK_IO, |
111 | RESTART_FROZEN_DISK_IO, |
112 | NOTHING, |
113 | }; |
114 | |
115 | /* encoding of request states for now. we don't actually need that many bits. |
116 | * we don't need to do atomic bit operations either, since most of the time we |
117 | * need to look at the connection state and/or manipulate some lists at the |
118 | * same time, so we should hold the request lock anyways. |
119 | */ |
120 | enum drbd_req_state_bits { |
121 | /* 3210 |
122 | * 0000: no local possible |
123 | * 0001: to be submitted |
124 | * UNUSED, we could map: 011: submitted, completion still pending |
125 | * 0110: completed ok |
126 | * 0010: completed with error |
127 | * 1001: Aborted (before completion) |
128 | * 1x10: Aborted and completed -> free |
129 | */ |
130 | __RQ_LOCAL_PENDING, |
131 | __RQ_LOCAL_COMPLETED, |
132 | __RQ_LOCAL_OK, |
133 | __RQ_LOCAL_ABORTED, |
134 | |
135 | /* 87654 |
136 | * 00000: no network possible |
137 | * 00001: to be send |
138 | * 00011: to be send, on worker queue |
139 | * 00101: sent, expecting recv_ack (B) or write_ack (C) |
140 | * 11101: sent, |
141 | * recv_ack (B) or implicit "ack" (A), |
142 | * still waiting for the barrier ack. |
143 | * master_bio may already be completed and invalidated. |
144 | * 11100: write acked (C), |
145 | * data received (for remote read, any protocol) |
146 | * or finally the barrier ack has arrived (B,A)... |
147 | * request can be freed |
148 | * 01100: neg-acked (write, protocol C) |
149 | * or neg-d-acked (read, any protocol) |
150 | * or killed from the transfer log |
151 | * during cleanup after connection loss |
152 | * request can be freed |
153 | * 01000: canceled or send failed... |
154 | * request can be freed |
155 | */ |
156 | |
157 | /* if "SENT" is not set, yet, this can still fail or be canceled. |
158 | * if "SENT" is set already, we still wait for an Ack packet. |
159 | * when cleared, the master_bio may be completed. |
160 | * in (B,A) the request object may still linger on the transaction log |
161 | * until the corresponding barrier ack comes in */ |
162 | __RQ_NET_PENDING, |
163 | |
164 | /* If it is QUEUED, and it is a WRITE, it is also registered in the |
165 | * transfer log. Currently we need this flag to avoid conflicts between |
166 | * worker canceling the request and tl_clear_barrier killing it from |
167 | * transfer log. We should restructure the code so this conflict does |
168 | * no longer occur. */ |
169 | __RQ_NET_QUEUED, |
170 | |
171 | /* well, actually only "handed over to the network stack". |
172 | * |
173 | * TODO can potentially be dropped because of the similar meaning |
174 | * of RQ_NET_SENT and ~RQ_NET_QUEUED. |
175 | * however it is not exactly the same. before we drop it |
176 | * we must ensure that we can tell a request with network part |
177 | * from a request without, regardless of what happens to it. */ |
178 | __RQ_NET_SENT, |
179 | |
180 | /* when set, the request may be freed (if RQ_NET_QUEUED is clear). |
181 | * basically this means the corresponding P_BARRIER_ACK was received */ |
182 | __RQ_NET_DONE, |
183 | |
184 | /* whether or not we know (C) or pretend (B,A) that the write |
185 | * was successfully written on the peer. |
186 | */ |
187 | __RQ_NET_OK, |
188 | |
189 | /* peer called drbd_set_in_sync() for this write */ |
190 | __RQ_NET_SIS, |
191 | |
192 | /* keep this last, its for the RQ_NET_MASK */ |
193 | __RQ_NET_MAX, |
194 | |
195 | /* Set when this is a write, clear for a read */ |
196 | __RQ_WRITE, |
197 | __RQ_WSAME, |
198 | __RQ_UNMAP, |
199 | __RQ_ZEROES, |
200 | |
201 | /* Should call drbd_al_complete_io() for this request... */ |
202 | __RQ_IN_ACT_LOG, |
203 | |
204 | /* This was the most recent request during some blk_finish_plug() |
205 | * or its implicit from-schedule equivalent. |
206 | * We may use it as hint to send a P_UNPLUG_REMOTE */ |
207 | __RQ_UNPLUG, |
208 | |
209 | /* The peer has sent a retry ACK */ |
210 | __RQ_POSTPONED, |
211 | |
212 | /* would have been completed, |
213 | * but was not, because of drbd_suspended() */ |
214 | __RQ_COMPLETION_SUSP, |
215 | |
216 | /* We expect a receive ACK (wire proto B) */ |
217 | __RQ_EXP_RECEIVE_ACK, |
218 | |
219 | /* We expect a write ACK (wite proto C) */ |
220 | __RQ_EXP_WRITE_ACK, |
221 | |
222 | /* waiting for a barrier ack, did an extra kref_get */ |
223 | __RQ_EXP_BARR_ACK, |
224 | }; |
225 | |
226 | #define RQ_LOCAL_PENDING (1UL << __RQ_LOCAL_PENDING) |
227 | #define RQ_LOCAL_COMPLETED (1UL << __RQ_LOCAL_COMPLETED) |
228 | #define RQ_LOCAL_OK (1UL << __RQ_LOCAL_OK) |
229 | #define RQ_LOCAL_ABORTED (1UL << __RQ_LOCAL_ABORTED) |
230 | |
231 | #define RQ_LOCAL_MASK ((RQ_LOCAL_ABORTED << 1)-1) |
232 | |
233 | #define RQ_NET_PENDING (1UL << __RQ_NET_PENDING) |
234 | #define RQ_NET_QUEUED (1UL << __RQ_NET_QUEUED) |
235 | #define RQ_NET_SENT (1UL << __RQ_NET_SENT) |
236 | #define RQ_NET_DONE (1UL << __RQ_NET_DONE) |
237 | #define RQ_NET_OK (1UL << __RQ_NET_OK) |
238 | #define RQ_NET_SIS (1UL << __RQ_NET_SIS) |
239 | |
240 | #define RQ_NET_MASK (((1UL << __RQ_NET_MAX)-1) & ~RQ_LOCAL_MASK) |
241 | |
242 | #define RQ_WRITE (1UL << __RQ_WRITE) |
243 | #define RQ_WSAME (1UL << __RQ_WSAME) |
244 | #define RQ_UNMAP (1UL << __RQ_UNMAP) |
245 | #define RQ_ZEROES (1UL << __RQ_ZEROES) |
246 | #define RQ_IN_ACT_LOG (1UL << __RQ_IN_ACT_LOG) |
247 | #define RQ_UNPLUG (1UL << __RQ_UNPLUG) |
248 | #define RQ_POSTPONED (1UL << __RQ_POSTPONED) |
249 | #define RQ_COMPLETION_SUSP (1UL << __RQ_COMPLETION_SUSP) |
250 | #define RQ_EXP_RECEIVE_ACK (1UL << __RQ_EXP_RECEIVE_ACK) |
251 | #define RQ_EXP_WRITE_ACK (1UL << __RQ_EXP_WRITE_ACK) |
252 | #define RQ_EXP_BARR_ACK (1UL << __RQ_EXP_BARR_ACK) |
253 | |
254 | /* For waking up the frozen transfer log mod_req() has to return if the request |
255 | should be counted in the epoch object*/ |
256 | #define MR_WRITE 1 |
257 | #define MR_READ 2 |
258 | |
259 | /* Short lived temporary struct on the stack. |
260 | * We could squirrel the error to be returned into |
261 | * bio->bi_iter.bi_size, or similar. But that would be too ugly. */ |
262 | struct bio_and_error { |
263 | struct bio *bio; |
264 | int error; |
265 | }; |
266 | |
267 | extern void start_new_tl_epoch(struct drbd_connection *connection); |
268 | extern void drbd_req_destroy(struct kref *kref); |
269 | extern int __req_mod(struct drbd_request *req, enum drbd_req_event what, |
270 | struct drbd_peer_device *peer_device, |
271 | struct bio_and_error *m); |
272 | extern void complete_master_bio(struct drbd_device *device, |
273 | struct bio_and_error *m); |
274 | extern void request_timer_fn(struct timer_list *t); |
275 | extern void tl_restart(struct drbd_connection *connection, enum drbd_req_event what); |
276 | extern void _tl_restart(struct drbd_connection *connection, enum drbd_req_event what); |
277 | extern void tl_abort_disk_io(struct drbd_device *device); |
278 | |
279 | /* this is in drbd_main.c */ |
280 | extern void drbd_restart_request(struct drbd_request *req); |
281 | |
282 | /* use this if you don't want to deal with calling complete_master_bio() |
283 | * outside the spinlock, e.g. when walking some list on cleanup. */ |
284 | static inline int _req_mod(struct drbd_request *req, enum drbd_req_event what, |
285 | struct drbd_peer_device *peer_device) |
286 | { |
287 | struct drbd_device *device = req->device; |
288 | struct bio_and_error m; |
289 | int rv; |
290 | |
291 | /* __req_mod possibly frees req, do not touch req after that! */ |
292 | rv = __req_mod(req, what, peer_device, m: &m); |
293 | if (m.bio) |
294 | complete_master_bio(device, m: &m); |
295 | |
296 | return rv; |
297 | } |
298 | |
299 | /* completion of master bio is outside of our spinlock. |
300 | * We still may or may not be inside some irqs disabled section |
301 | * of the lower level driver completion callback, so we need to |
302 | * spin_lock_irqsave here. */ |
303 | static inline int req_mod(struct drbd_request *req, |
304 | enum drbd_req_event what, |
305 | struct drbd_peer_device *peer_device) |
306 | { |
307 | unsigned long flags; |
308 | struct drbd_device *device = req->device; |
309 | struct bio_and_error m; |
310 | int rv; |
311 | |
312 | spin_lock_irqsave(&device->resource->req_lock, flags); |
313 | rv = __req_mod(req, what, peer_device, m: &m); |
314 | spin_unlock_irqrestore(lock: &device->resource->req_lock, flags); |
315 | |
316 | if (m.bio) |
317 | complete_master_bio(device, m: &m); |
318 | |
319 | return rv; |
320 | } |
321 | |
322 | extern bool drbd_should_do_remote(union drbd_dev_state); |
323 | |
324 | #endif |
325 | |