blob: 6b91b9ab1d41f537bc81e703ecffa710f0efcdf8 [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * Copyright (C) 2004 SUSE LINUX Products GmbH. All rights reserved.
3 * Copyright (C) 2004 Red Hat, Inc. All rights reserved.
4 *
5 * This file is released under the GPL.
6 *
7 * Multipath support for EMC CLARiiON AX/CX-series hardware.
8 */
9
10#include "dm.h"
11#include "dm-hw-handler.h"
12#include <scsi/scsi.h>
13#include <scsi/scsi_cmnd.h>
14
Alasdair G Kergon72d94862006-06-26 00:27:35 -070015#define DM_MSG_PREFIX "multipath emc"
16
Linus Torvalds1da177e2005-04-16 15:20:36 -070017struct emc_handler {
18 spinlock_t lock;
19
20 /* Whether we should send the short trespass command (FC-series)
21 * or the long version (default for AX/CX CLARiiON arrays). */
22 unsigned short_trespass;
23 /* Whether or not to honor SCSI reservations when initiating a
24 * switch-over. Default: Don't. */
25 unsigned hr;
26
27 unsigned char sense[SCSI_SENSE_BUFFERSIZE];
28};
29
30#define TRESPASS_PAGE 0x22
31#define EMC_FAILOVER_TIMEOUT (60 * HZ)
32
33/* Code borrowed from dm-lsi-rdac by Mike Christie */
34
35static inline void free_bio(struct bio *bio)
36{
37 __free_page(bio->bi_io_vec[0].bv_page);
38 bio_put(bio);
39}
40
NeilBrown6712ecf2007-09-27 12:47:43 +020041static void emc_endio(struct bio *bio, int error)
Linus Torvalds1da177e2005-04-16 15:20:36 -070042{
Josef "Jeff" Sipekc922d5f2006-12-08 02:36:33 -080043 struct dm_path *path = bio->bi_private;
Linus Torvalds1da177e2005-04-16 15:20:36 -070044
Linus Torvalds1da177e2005-04-16 15:20:36 -070045 /* We also need to look at the sense keys here whether or not to
46 * switch to the next PG etc.
47 *
48 * For now simple logic: either it works or it doesn't.
49 */
50 if (error)
51 dm_pg_init_complete(path, MP_FAIL_PATH);
52 else
53 dm_pg_init_complete(path, 0);
54
55 /* request is freed in block layer */
56 free_bio(bio);
Linus Torvalds1da177e2005-04-16 15:20:36 -070057}
58
Josef "Jeff" Sipekc922d5f2006-12-08 02:36:33 -080059static struct bio *get_failover_bio(struct dm_path *path, unsigned data_size)
Linus Torvalds1da177e2005-04-16 15:20:36 -070060{
61 struct bio *bio;
62 struct page *page;
63
64 bio = bio_alloc(GFP_ATOMIC, 1);
65 if (!bio) {
Alasdair G Kergon72d94862006-06-26 00:27:35 -070066 DMERR("get_failover_bio: bio_alloc() failed.");
Linus Torvalds1da177e2005-04-16 15:20:36 -070067 return NULL;
68 }
69
70 bio->bi_rw |= (1 << BIO_RW);
71 bio->bi_bdev = path->dev->bdev;
72 bio->bi_sector = 0;
73 bio->bi_private = path;
74 bio->bi_end_io = emc_endio;
75
76 page = alloc_page(GFP_ATOMIC);
77 if (!page) {
Alasdair G Kergon72d94862006-06-26 00:27:35 -070078 DMERR("get_failover_bio: alloc_page() failed.");
Linus Torvalds1da177e2005-04-16 15:20:36 -070079 bio_put(bio);
80 return NULL;
81 }
82
83 if (bio_add_page(bio, page, data_size, 0) != data_size) {
Alasdair G Kergond3364162007-10-19 22:38:56 +010084 DMERR("get_failover_bio: bio_add_page() failed.");
Linus Torvalds1da177e2005-04-16 15:20:36 -070085 __free_page(page);
86 bio_put(bio);
87 return NULL;
88 }
89
90 return bio;
91}
92
93static struct request *get_failover_req(struct emc_handler *h,
Josef "Jeff" Sipekc922d5f2006-12-08 02:36:33 -080094 struct bio *bio, struct dm_path *path)
Linus Torvalds1da177e2005-04-16 15:20:36 -070095{
96 struct request *rq;
97 struct block_device *bdev = bio->bi_bdev;
98 struct request_queue *q = bdev_get_queue(bdev);
99
100 /* FIXME: Figure out why it fails with GFP_ATOMIC. */
101 rq = blk_get_request(q, WRITE, __GFP_WAIT);
102 if (!rq) {
Alasdair G Kergon72d94862006-06-26 00:27:35 -0700103 DMERR("get_failover_req: blk_get_request failed");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700104 return NULL;
105 }
106
NeilBrown668465722007-08-16 13:31:28 +0200107 blk_rq_append_bio(q, rq, bio);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700108
109 rq->sense = h->sense;
110 memset(rq->sense, 0, SCSI_SENSE_BUFFERSIZE);
111 rq->sense_len = 0;
112
113 memset(&rq->cmd, 0, BLK_MAX_CDB);
114
115 rq->timeout = EMC_FAILOVER_TIMEOUT;
Jens Axboe4aff5e22006-08-10 08:44:47 +0200116 rq->cmd_type = REQ_TYPE_BLOCK_PC;
117 rq->cmd_flags |= REQ_FAILFAST | REQ_NOMERGE;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700118
119 return rq;
120}
121
122static struct request *emc_trespass_get(struct emc_handler *h,
Josef "Jeff" Sipekc922d5f2006-12-08 02:36:33 -0800123 struct dm_path *path)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700124{
125 struct bio *bio;
126 struct request *rq;
127 unsigned char *page22;
128 unsigned char long_trespass_pg[] = {
129 0, 0, 0, 0,
130 TRESPASS_PAGE, /* Page code */
131 0x09, /* Page length - 2 */
132 h->hr ? 0x01 : 0x81, /* Trespass code + Honor reservation bit */
133 0xff, 0xff, /* Trespass target */
134 0, 0, 0, 0, 0, 0 /* Reserved bytes / unknown */
135 };
136 unsigned char short_trespass_pg[] = {
137 0, 0, 0, 0,
138 TRESPASS_PAGE, /* Page code */
139 0x02, /* Page length - 2 */
140 h->hr ? 0x01 : 0x81, /* Trespass code + Honor reservation bit */
141 0xff, /* Trespass target */
142 };
143 unsigned data_size = h->short_trespass ? sizeof(short_trespass_pg) :
144 sizeof(long_trespass_pg);
145
146 /* get bio backing */
147 if (data_size > PAGE_SIZE)
148 /* this should never happen */
149 return NULL;
150
151 bio = get_failover_bio(path, data_size);
152 if (!bio) {
Alasdair G Kergon72d94862006-06-26 00:27:35 -0700153 DMERR("emc_trespass_get: no bio");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700154 return NULL;
155 }
156
157 page22 = (unsigned char *)bio_data(bio);
158 memset(page22, 0, data_size);
159
160 memcpy(page22, h->short_trespass ?
161 short_trespass_pg : long_trespass_pg, data_size);
162
163 /* get request for block layer packet command */
164 rq = get_failover_req(h, bio, path);
165 if (!rq) {
Alasdair G Kergon72d94862006-06-26 00:27:35 -0700166 DMERR("emc_trespass_get: no rq");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700167 free_bio(bio);
168 return NULL;
169 }
170
171 /* Prepare the command. */
172 rq->cmd[0] = MODE_SELECT;
173 rq->cmd[1] = 0x10;
174 rq->cmd[4] = data_size;
175 rq->cmd_len = COMMAND_SIZE(rq->cmd[0]);
176
177 return rq;
178}
179
180static void emc_pg_init(struct hw_handler *hwh, unsigned bypassed,
Josef "Jeff" Sipekc922d5f2006-12-08 02:36:33 -0800181 struct dm_path *path)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700182{
183 struct request *rq;
184 struct request_queue *q = bdev_get_queue(path->dev->bdev);
185
186 /*
187 * We can either blindly init the pg (then look at the sense),
188 * or we can send some commands to get the state here (then
189 * possibly send the fo cmnd), or we can also have the
190 * initial state passed into us and then get an update here.
191 */
192 if (!q) {
Alasdair G Kergon72d94862006-06-26 00:27:35 -0700193 DMINFO("emc_pg_init: no queue");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700194 goto fail_path;
195 }
196
197 /* FIXME: The request should be pre-allocated. */
198 rq = emc_trespass_get(hwh->context, path);
199 if (!rq) {
Alasdair G Kergon72d94862006-06-26 00:27:35 -0700200 DMERR("emc_pg_init: no rq");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700201 goto fail_path;
202 }
203
Alasdair G Kergon72d94862006-06-26 00:27:35 -0700204 DMINFO("emc_pg_init: sending switch-over command");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700205 elv_add_request(q, rq, ELEVATOR_INSERT_FRONT, 1);
206 return;
207
208fail_path:
209 dm_pg_init_complete(path, MP_FAIL_PATH);
210}
211
212static struct emc_handler *alloc_emc_handler(void)
213{
Dmitry Monakhov094262d2007-10-19 22:38:51 +0100214 struct emc_handler *h = kzalloc(sizeof(*h), GFP_KERNEL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700215
Dmitry Monakhov094262d2007-10-19 22:38:51 +0100216 if (h)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700217 spin_lock_init(&h->lock);
218
219 return h;
220}
221
222static int emc_create(struct hw_handler *hwh, unsigned argc, char **argv)
223{
224 struct emc_handler *h;
225 unsigned hr, short_trespass;
226
227 if (argc == 0) {
228 /* No arguments: use defaults */
229 hr = 0;
230 short_trespass = 0;
231 } else if (argc != 2) {
Alasdair G Kergon72d94862006-06-26 00:27:35 -0700232 DMWARN("incorrect number of arguments");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700233 return -EINVAL;
234 } else {
235 if ((sscanf(argv[0], "%u", &short_trespass) != 1)
236 || (short_trespass > 1)) {
Alasdair G Kergon72d94862006-06-26 00:27:35 -0700237 DMWARN("invalid trespass mode selected");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700238 return -EINVAL;
239 }
240
241 if ((sscanf(argv[1], "%u", &hr) != 1)
242 || (hr > 1)) {
Alasdair G Kergon72d94862006-06-26 00:27:35 -0700243 DMWARN("invalid honor reservation flag selected");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700244 return -EINVAL;
245 }
246 }
247
248 h = alloc_emc_handler();
249 if (!h)
250 return -ENOMEM;
251
Linus Torvalds1da177e2005-04-16 15:20:36 -0700252 hwh->context = h;
253
254 if ((h->short_trespass = short_trespass))
Alasdair G Kergon72d94862006-06-26 00:27:35 -0700255 DMWARN("short trespass command will be send");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700256 else
Alasdair G Kergon72d94862006-06-26 00:27:35 -0700257 DMWARN("long trespass command will be send");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700258
259 if ((h->hr = hr))
Alasdair G Kergon72d94862006-06-26 00:27:35 -0700260 DMWARN("honor reservation bit will be set");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700261 else
Alasdair G Kergon72d94862006-06-26 00:27:35 -0700262 DMWARN("honor reservation bit will not be set (default)");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700263
264 return 0;
265}
266
267static void emc_destroy(struct hw_handler *hwh)
268{
269 struct emc_handler *h = (struct emc_handler *) hwh->context;
270
271 kfree(h);
272 hwh->context = NULL;
273}
274
275static unsigned emc_error(struct hw_handler *hwh, struct bio *bio)
276{
277 /* FIXME: Patch from axboe still missing */
278#if 0
279 int sense;
280
281 if (bio->bi_error & BIO_SENSE) {
282 sense = bio->bi_error & 0xffffff; /* sense key / asc / ascq */
283
284 if (sense == 0x020403) {
285 /* LUN Not Ready - Manual Intervention Required
286 * indicates this is a passive path.
287 *
288 * FIXME: However, if this is seen and EVPD C0
289 * indicates that this is due to a NDU in
290 * progress, we should set FAIL_PATH too.
291 * This indicates we might have to do a SCSI
292 * inquiry in the end_io path. Ugh. */
293 return MP_BYPASS_PG | MP_RETRY_IO;
294 } else if (sense == 0x052501) {
295 /* An array based copy is in progress. Do not
296 * fail the path, do not bypass to another PG,
297 * do not retry. Fail the IO immediately.
298 * (Actually this is the same conclusion as in
299 * the default handler, but lets make sure.) */
300 return 0;
301 } else if (sense == 0x062900) {
302 /* Unit Attention Code. This is the first IO
303 * to the new path, so just retry. */
304 return MP_RETRY_IO;
305 }
306 }
307#endif
308
309 /* Try default handler */
310 return dm_scsi_err_handler(hwh, bio);
311}
312
313static struct hw_handler_type emc_hwh = {
314 .name = "emc",
315 .module = THIS_MODULE,
316 .create = emc_create,
317 .destroy = emc_destroy,
318 .pg_init = emc_pg_init,
319 .error = emc_error,
320};
321
322static int __init dm_emc_init(void)
323{
324 int r = dm_register_hw_handler(&emc_hwh);
325
326 if (r < 0)
Alasdair G Kergon72d94862006-06-26 00:27:35 -0700327 DMERR("register failed %d", r);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700328
Alasdair G Kergon72d94862006-06-26 00:27:35 -0700329 DMINFO("version 0.0.3 loaded");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700330
331 return r;
332}
333
334static void __exit dm_emc_exit(void)
335{
336 int r = dm_unregister_hw_handler(&emc_hwh);
337
338 if (r < 0)
Alasdair G Kergon72d94862006-06-26 00:27:35 -0700339 DMERR("unregister failed %d", r);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700340}
341
342module_init(dm_emc_init);
343module_exit(dm_emc_exit);
344
345MODULE_DESCRIPTION(DM_NAME " EMC CX/AX/FC-family multipath");
346MODULE_AUTHOR("Lars Marowsky-Bree <lmb@suse.de>");
347MODULE_LICENSE("GPL");