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1da177e4 LT |
1 | /* |
2 | * Copyright (C) 2001-2003 Sistina Software (UK) Limited. | |
3 | * | |
4 | * This file is released under the GPL. | |
5 | */ | |
6 | ||
7 | #include "dm.h" | |
8 | ||
9 | #include <linux/module.h> | |
10 | #include <linux/init.h> | |
11 | #include <linux/blkdev.h> | |
12 | #include <linux/bio.h> | |
13 | #include <linux/slab.h> | |
6f3c3f0a | 14 | #include <linux/log2.h> |
1da177e4 | 15 | |
72d94861 | 16 | #define DM_MSG_PREFIX "striped" |
a25eb944 | 17 | #define DM_IO_ERROR_THRESHOLD 15 |
72d94861 | 18 | |
1da177e4 LT |
19 | struct stripe { |
20 | struct dm_dev *dev; | |
21 | sector_t physical_start; | |
a25eb944 BW |
22 | |
23 | atomic_t error_count; | |
1da177e4 LT |
24 | }; |
25 | ||
26 | struct stripe_c { | |
27 | uint32_t stripes; | |
28 | ||
29 | /* The size of this target / num. stripes */ | |
30 | sector_t stripe_width; | |
31 | ||
32 | /* stripe chunk size */ | |
33 | uint32_t chunk_shift; | |
34 | sector_t chunk_mask; | |
35 | ||
a25eb944 BW |
36 | /* Needed for handling events */ |
37 | struct dm_target *ti; | |
38 | ||
39 | /* Work struct used for triggering events*/ | |
40 | struct work_struct kstriped_ws; | |
41 | ||
1da177e4 LT |
42 | struct stripe stripe[0]; |
43 | }; | |
44 | ||
a25eb944 BW |
45 | static struct workqueue_struct *kstriped; |
46 | ||
47 | /* | |
48 | * An event is triggered whenever a drive | |
49 | * drops out of a stripe volume. | |
50 | */ | |
51 | static void trigger_event(struct work_struct *work) | |
52 | { | |
53 | struct stripe_c *sc = container_of(work, struct stripe_c, kstriped_ws); | |
54 | ||
55 | dm_table_event(sc->ti->table); | |
56 | ||
57 | } | |
58 | ||
1da177e4 LT |
59 | static inline struct stripe_c *alloc_context(unsigned int stripes) |
60 | { | |
61 | size_t len; | |
62 | ||
63 | if (array_too_big(sizeof(struct stripe_c), sizeof(struct stripe), | |
64 | stripes)) | |
65 | return NULL; | |
66 | ||
67 | len = sizeof(struct stripe_c) + (sizeof(struct stripe) * stripes); | |
68 | ||
69 | return kmalloc(len, GFP_KERNEL); | |
70 | } | |
71 | ||
72 | /* | |
73 | * Parse a single <dev> <sector> pair | |
74 | */ | |
75 | static int get_stripe(struct dm_target *ti, struct stripe_c *sc, | |
76 | unsigned int stripe, char **argv) | |
77 | { | |
4ee218cd | 78 | unsigned long long start; |
1da177e4 | 79 | |
4ee218cd | 80 | if (sscanf(argv[1], "%llu", &start) != 1) |
1da177e4 LT |
81 | return -EINVAL; |
82 | ||
83 | if (dm_get_device(ti, argv[0], start, sc->stripe_width, | |
84 | dm_table_get_mode(ti->table), | |
85 | &sc->stripe[stripe].dev)) | |
86 | return -ENXIO; | |
87 | ||
88 | sc->stripe[stripe].physical_start = start; | |
a25eb944 | 89 | |
1da177e4 LT |
90 | return 0; |
91 | } | |
92 | ||
93 | /* | |
94 | * Construct a striped mapping. | |
95 | * <number of stripes> <chunk size (2^^n)> [<dev_path> <offset>]+ | |
96 | */ | |
97 | static int stripe_ctr(struct dm_target *ti, unsigned int argc, char **argv) | |
98 | { | |
99 | struct stripe_c *sc; | |
100 | sector_t width; | |
101 | uint32_t stripes; | |
102 | uint32_t chunk_size; | |
103 | char *end; | |
104 | int r; | |
105 | unsigned int i; | |
106 | ||
107 | if (argc < 2) { | |
72d94861 | 108 | ti->error = "Not enough arguments"; |
1da177e4 LT |
109 | return -EINVAL; |
110 | } | |
111 | ||
112 | stripes = simple_strtoul(argv[0], &end, 10); | |
113 | if (*end) { | |
72d94861 | 114 | ti->error = "Invalid stripe count"; |
1da177e4 LT |
115 | return -EINVAL; |
116 | } | |
117 | ||
118 | chunk_size = simple_strtoul(argv[1], &end, 10); | |
119 | if (*end) { | |
72d94861 | 120 | ti->error = "Invalid chunk_size"; |
1da177e4 LT |
121 | return -EINVAL; |
122 | } | |
123 | ||
124 | /* | |
125 | * chunk_size is a power of two | |
126 | */ | |
6f3c3f0a | 127 | if (!is_power_of_2(chunk_size) || |
1da177e4 | 128 | (chunk_size < (PAGE_SIZE >> SECTOR_SHIFT))) { |
72d94861 | 129 | ti->error = "Invalid chunk size"; |
1da177e4 LT |
130 | return -EINVAL; |
131 | } | |
132 | ||
a22c96c7 | 133 | if (ti->len & (chunk_size - 1)) { |
72d94861 | 134 | ti->error = "Target length not divisible by " |
8ba32fde KC |
135 | "chunk size"; |
136 | return -EINVAL; | |
137 | } | |
138 | ||
1da177e4 LT |
139 | width = ti->len; |
140 | if (sector_div(width, stripes)) { | |
72d94861 | 141 | ti->error = "Target length not divisible by " |
1da177e4 LT |
142 | "number of stripes"; |
143 | return -EINVAL; | |
144 | } | |
145 | ||
146 | /* | |
147 | * Do we have enough arguments for that many stripes ? | |
148 | */ | |
149 | if (argc != (2 + 2 * stripes)) { | |
72d94861 | 150 | ti->error = "Not enough destinations " |
1da177e4 LT |
151 | "specified"; |
152 | return -EINVAL; | |
153 | } | |
154 | ||
155 | sc = alloc_context(stripes); | |
156 | if (!sc) { | |
72d94861 | 157 | ti->error = "Memory allocation for striped context " |
1da177e4 LT |
158 | "failed"; |
159 | return -ENOMEM; | |
160 | } | |
161 | ||
a25eb944 BW |
162 | INIT_WORK(&sc->kstriped_ws, trigger_event); |
163 | ||
164 | /* Set pointer to dm target; used in trigger_event */ | |
165 | sc->ti = ti; | |
166 | ||
1da177e4 LT |
167 | sc->stripes = stripes; |
168 | sc->stripe_width = width; | |
169 | ti->split_io = chunk_size; | |
170 | ||
171 | sc->chunk_mask = ((sector_t) chunk_size) - 1; | |
172 | for (sc->chunk_shift = 0; chunk_size; sc->chunk_shift++) | |
173 | chunk_size >>= 1; | |
174 | sc->chunk_shift--; | |
175 | ||
176 | /* | |
177 | * Get the stripe destinations. | |
178 | */ | |
179 | for (i = 0; i < stripes; i++) { | |
180 | argv += 2; | |
181 | ||
182 | r = get_stripe(ti, sc, i, argv); | |
183 | if (r < 0) { | |
72d94861 | 184 | ti->error = "Couldn't parse stripe destination"; |
1da177e4 LT |
185 | while (i--) |
186 | dm_put_device(ti, sc->stripe[i].dev); | |
187 | kfree(sc); | |
188 | return r; | |
189 | } | |
a25eb944 | 190 | atomic_set(&(sc->stripe[i].error_count), 0); |
1da177e4 LT |
191 | } |
192 | ||
193 | ti->private = sc; | |
a25eb944 | 194 | |
1da177e4 LT |
195 | return 0; |
196 | } | |
197 | ||
198 | static void stripe_dtr(struct dm_target *ti) | |
199 | { | |
200 | unsigned int i; | |
201 | struct stripe_c *sc = (struct stripe_c *) ti->private; | |
202 | ||
203 | for (i = 0; i < sc->stripes; i++) | |
204 | dm_put_device(ti, sc->stripe[i].dev); | |
205 | ||
a25eb944 | 206 | flush_workqueue(kstriped); |
1da177e4 LT |
207 | kfree(sc); |
208 | } | |
209 | ||
210 | static int stripe_map(struct dm_target *ti, struct bio *bio, | |
211 | union map_info *map_context) | |
212 | { | |
213 | struct stripe_c *sc = (struct stripe_c *) ti->private; | |
214 | ||
215 | sector_t offset = bio->bi_sector - ti->begin; | |
216 | sector_t chunk = offset >> sc->chunk_shift; | |
217 | uint32_t stripe = sector_div(chunk, sc->stripes); | |
218 | ||
219 | bio->bi_bdev = sc->stripe[stripe].dev->bdev; | |
220 | bio->bi_sector = sc->stripe[stripe].physical_start + | |
221 | (chunk << sc->chunk_shift) + (offset & sc->chunk_mask); | |
d2a7ad29 | 222 | return DM_MAPIO_REMAPPED; |
1da177e4 LT |
223 | } |
224 | ||
4f7f5c67 BW |
225 | /* |
226 | * Stripe status: | |
227 | * | |
228 | * INFO | |
229 | * #stripes [stripe_name <stripe_name>] [group word count] | |
230 | * [error count 'A|D' <error count 'A|D'>] | |
231 | * | |
232 | * TABLE | |
233 | * #stripes [stripe chunk size] | |
234 | * [stripe_name physical_start <stripe_name physical_start>] | |
235 | * | |
236 | */ | |
237 | ||
1da177e4 LT |
238 | static int stripe_status(struct dm_target *ti, |
239 | status_type_t type, char *result, unsigned int maxlen) | |
240 | { | |
241 | struct stripe_c *sc = (struct stripe_c *) ti->private; | |
4f7f5c67 | 242 | char buffer[sc->stripes + 1]; |
1da177e4 LT |
243 | unsigned int sz = 0; |
244 | unsigned int i; | |
245 | ||
246 | switch (type) { | |
247 | case STATUSTYPE_INFO: | |
4f7f5c67 BW |
248 | DMEMIT("%d ", sc->stripes); |
249 | for (i = 0; i < sc->stripes; i++) { | |
250 | DMEMIT("%s ", sc->stripe[i].dev->name); | |
251 | buffer[i] = atomic_read(&(sc->stripe[i].error_count)) ? | |
252 | 'D' : 'A'; | |
253 | } | |
254 | buffer[i] = '\0'; | |
255 | DMEMIT("1 %s", buffer); | |
1da177e4 LT |
256 | break; |
257 | ||
258 | case STATUSTYPE_TABLE: | |
4ee218cd AM |
259 | DMEMIT("%d %llu", sc->stripes, |
260 | (unsigned long long)sc->chunk_mask + 1); | |
1da177e4 | 261 | for (i = 0; i < sc->stripes; i++) |
4ee218cd AM |
262 | DMEMIT(" %s %llu", sc->stripe[i].dev->name, |
263 | (unsigned long long)sc->stripe[i].physical_start); | |
1da177e4 LT |
264 | break; |
265 | } | |
266 | return 0; | |
267 | } | |
268 | ||
a25eb944 BW |
269 | static int stripe_end_io(struct dm_target *ti, struct bio *bio, |
270 | int error, union map_info *map_context) | |
271 | { | |
272 | unsigned i; | |
273 | char major_minor[16]; | |
274 | struct stripe_c *sc = ti->private; | |
275 | ||
276 | if (!error) | |
277 | return 0; /* I/O complete */ | |
278 | ||
279 | if ((error == -EWOULDBLOCK) && bio_rw_ahead(bio)) | |
280 | return error; | |
281 | ||
282 | if (error == -EOPNOTSUPP) | |
283 | return error; | |
284 | ||
285 | memset(major_minor, 0, sizeof(major_minor)); | |
286 | sprintf(major_minor, "%d:%d", | |
287 | bio->bi_bdev->bd_disk->major, | |
288 | bio->bi_bdev->bd_disk->first_minor); | |
289 | ||
290 | /* | |
291 | * Test to see which stripe drive triggered the event | |
292 | * and increment error count for all stripes on that device. | |
293 | * If the error count for a given device exceeds the threshold | |
294 | * value we will no longer trigger any further events. | |
295 | */ | |
296 | for (i = 0; i < sc->stripes; i++) | |
297 | if (!strcmp(sc->stripe[i].dev->name, major_minor)) { | |
298 | atomic_inc(&(sc->stripe[i].error_count)); | |
299 | if (atomic_read(&(sc->stripe[i].error_count)) < | |
300 | DM_IO_ERROR_THRESHOLD) | |
301 | queue_work(kstriped, &sc->kstriped_ws); | |
302 | } | |
303 | ||
304 | return error; | |
305 | } | |
306 | ||
1da177e4 LT |
307 | static struct target_type stripe_target = { |
308 | .name = "striped", | |
a25eb944 | 309 | .version = {1, 1, 0}, |
1da177e4 LT |
310 | .module = THIS_MODULE, |
311 | .ctr = stripe_ctr, | |
312 | .dtr = stripe_dtr, | |
313 | .map = stripe_map, | |
a25eb944 | 314 | .end_io = stripe_end_io, |
1da177e4 LT |
315 | .status = stripe_status, |
316 | }; | |
317 | ||
318 | int __init dm_stripe_init(void) | |
319 | { | |
320 | int r; | |
321 | ||
322 | r = dm_register_target(&stripe_target); | |
323 | if (r < 0) | |
72d94861 | 324 | DMWARN("target registration failed"); |
1da177e4 | 325 | |
a25eb944 BW |
326 | kstriped = create_singlethread_workqueue("kstriped"); |
327 | if (!kstriped) { | |
328 | DMERR("failed to create workqueue kstriped"); | |
329 | dm_unregister_target(&stripe_target); | |
330 | return -ENOMEM; | |
331 | } | |
332 | ||
1da177e4 LT |
333 | return r; |
334 | } | |
335 | ||
336 | void dm_stripe_exit(void) | |
337 | { | |
338 | if (dm_unregister_target(&stripe_target)) | |
72d94861 | 339 | DMWARN("target unregistration failed"); |
1da177e4 | 340 | |
a25eb944 BW |
341 | destroy_workqueue(kstriped); |
342 | ||
1da177e4 LT |
343 | return; |
344 | } |