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 bio_and_error *m); 271 extern void complete_master_bio(struct drbd_device *device, 272 struct bio_and_error *m); 273 extern void request_timer_fn(struct timer_list *t); 274 extern void tl_restart(struct drbd_connection *connection, enum drbd_req_event what); 275 extern void _tl_restart(struct drbd_connection *connection, enum drbd_req_event what); 276 extern void tl_abort_disk_io(struct drbd_device *device); 277 278 /* this is in drbd_main.c */ 279 extern void drbd_restart_request(struct drbd_request *req); 280 281 /* use this if you don't want to deal with calling complete_master_bio() 282 * outside the spinlock, e.g. when walking some list on cleanup. */ 283 static inline int _req_mod(struct drbd_request *req, enum drbd_req_event what) 284 { 285 struct drbd_device *device = req->device; 286 struct bio_and_error m; 287 int rv; 288 289 /* __req_mod possibly frees req, do not touch req after that! */ 290 rv = __req_mod(req, what, &m); 291 if (m.bio) 292 complete_master_bio(device, &m); 293 294 return rv; 295 } 296 297 /* completion of master bio is outside of our spinlock. 298 * We still may or may not be inside some irqs disabled section 299 * of the lower level driver completion callback, so we need to 300 * spin_lock_irqsave here. */ 301 static inline int req_mod(struct drbd_request *req, 302 enum drbd_req_event what) 303 { 304 unsigned long flags; 305 struct drbd_device *device = req->device; 306 struct bio_and_error m; 307 int rv; 308 309 spin_lock_irqsave(&device->resource->req_lock, flags); 310 rv = __req_mod(req, what, &m); 311 spin_unlock_irqrestore(&device->resource->req_lock, flags); 312 313 if (m.bio) 314 complete_master_bio(device, &m); 315 316 return rv; 317 } 318 319 extern bool drbd_should_do_remote(union drbd_dev_state); 320 321 #endif 322