Commit | Line | Data |
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1da177e4 LT |
1 | /* |
2 | linear.c : Multiple Devices driver for Linux | |
3 | Copyright (C) 1994-96 Marc ZYNGIER | |
4 | <zyngier@ufr-info-p7.ibp.fr> or | |
5 | <maz@gloups.fdn.fr> | |
6 | ||
7 | Linear mode management functions. | |
8 | ||
9 | This program is free software; you can redistribute it and/or modify | |
10 | it under the terms of the GNU General Public License as published by | |
11 | the Free Software Foundation; either version 2, or (at your option) | |
12 | any later version. | |
13 | ||
14 | You should have received a copy of the GNU General Public License | |
15 | (for example /usr/src/linux/COPYING); if not, write to the Free | |
16 | Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. | |
17 | */ | |
18 | ||
bff61975 N |
19 | #include <linux/blkdev.h> |
20 | #include <linux/raid/md_u.h> | |
bff61975 | 21 | #include <linux/seq_file.h> |
43b2e5d8 | 22 | #include "md.h" |
ef740c37 | 23 | #include "linear.h" |
1da177e4 | 24 | |
1da177e4 LT |
25 | /* |
26 | * find which device holds a particular offset | |
27 | */ | |
28 | static inline dev_info_t *which_dev(mddev_t *mddev, sector_t sector) | |
29 | { | |
aece3d1f | 30 | int lo, mid, hi; |
af11c397 | 31 | linear_conf_t *conf; |
1da177e4 | 32 | |
aece3d1f SS |
33 | lo = 0; |
34 | hi = mddev->raid_disks - 1; | |
af11c397 | 35 | conf = rcu_dereference(mddev->private); |
1da177e4 | 36 | |
aece3d1f SS |
37 | /* |
38 | * Binary Search | |
39 | */ | |
40 | ||
41 | while (hi > lo) { | |
42 | ||
43 | mid = (hi + lo) / 2; | |
44 | if (sector < conf->disks[mid].end_sector) | |
45 | hi = mid; | |
46 | else | |
47 | lo = mid + 1; | |
48 | } | |
49 | ||
50 | return conf->disks + lo; | |
1da177e4 LT |
51 | } |
52 | ||
53 | /** | |
15945fee | 54 | * linear_mergeable_bvec -- tell bio layer if two requests can be merged |
1da177e4 | 55 | * @q: request queue |
cc371e66 | 56 | * @bvm: properties of new bio |
1da177e4 LT |
57 | * @biovec: the request that could be merged to it. |
58 | * | |
59 | * Return amount of bytes we can take at this offset | |
60 | */ | |
cc371e66 AK |
61 | static int linear_mergeable_bvec(struct request_queue *q, |
62 | struct bvec_merge_data *bvm, | |
63 | struct bio_vec *biovec) | |
1da177e4 LT |
64 | { |
65 | mddev_t *mddev = q->queuedata; | |
66 | dev_info_t *dev0; | |
cc371e66 AK |
67 | unsigned long maxsectors, bio_sectors = bvm->bi_size >> 9; |
68 | sector_t sector = bvm->bi_sector + get_start_sect(bvm->bi_bdev); | |
1da177e4 | 69 | |
af11c397 | 70 | rcu_read_lock(); |
1da177e4 | 71 | dev0 = which_dev(mddev, sector); |
4db7cdc8 | 72 | maxsectors = dev0->end_sector - sector; |
af11c397 | 73 | rcu_read_unlock(); |
1da177e4 LT |
74 | |
75 | if (maxsectors < bio_sectors) | |
76 | maxsectors = 0; | |
77 | else | |
78 | maxsectors -= bio_sectors; | |
79 | ||
80 | if (maxsectors <= (PAGE_SIZE >> 9 ) && bio_sectors == 0) | |
81 | return biovec->bv_len; | |
82 | /* The bytes available at this offset could be really big, | |
83 | * so we cap at 2^31 to avoid overflow */ | |
84 | if (maxsectors > (1 << (31-9))) | |
85 | return 1<<31; | |
86 | return maxsectors << 9; | |
87 | } | |
88 | ||
165125e1 | 89 | static void linear_unplug(struct request_queue *q) |
1da177e4 LT |
90 | { |
91 | mddev_t *mddev = q->queuedata; | |
af11c397 | 92 | linear_conf_t *conf; |
1da177e4 LT |
93 | int i; |
94 | ||
af11c397 S |
95 | rcu_read_lock(); |
96 | conf = rcu_dereference(mddev->private); | |
97 | ||
1da177e4 | 98 | for (i=0; i < mddev->raid_disks; i++) { |
165125e1 | 99 | struct request_queue *r_queue = bdev_get_queue(conf->disks[i].rdev->bdev); |
2ad8b1ef | 100 | blk_unplug(r_queue); |
1da177e4 | 101 | } |
af11c397 | 102 | rcu_read_unlock(); |
1da177e4 LT |
103 | } |
104 | ||
26be34dc N |
105 | static int linear_congested(void *data, int bits) |
106 | { | |
107 | mddev_t *mddev = data; | |
af11c397 | 108 | linear_conf_t *conf; |
26be34dc N |
109 | int i, ret = 0; |
110 | ||
af11c397 S |
111 | rcu_read_lock(); |
112 | conf = rcu_dereference(mddev->private); | |
113 | ||
26be34dc | 114 | for (i = 0; i < mddev->raid_disks && !ret ; i++) { |
165125e1 | 115 | struct request_queue *q = bdev_get_queue(conf->disks[i].rdev->bdev); |
26be34dc N |
116 | ret |= bdi_congested(&q->backing_dev_info, bits); |
117 | } | |
af11c397 S |
118 | |
119 | rcu_read_unlock(); | |
26be34dc N |
120 | return ret; |
121 | } | |
122 | ||
80c3a6ce DW |
123 | static sector_t linear_size(mddev_t *mddev, sector_t sectors, int raid_disks) |
124 | { | |
af11c397 S |
125 | linear_conf_t *conf; |
126 | sector_t array_sectors; | |
80c3a6ce | 127 | |
af11c397 S |
128 | rcu_read_lock(); |
129 | conf = rcu_dereference(mddev->private); | |
80c3a6ce DW |
130 | WARN_ONCE(sectors || raid_disks, |
131 | "%s does not support generic reshape\n", __func__); | |
af11c397 S |
132 | array_sectors = conf->array_sectors; |
133 | rcu_read_unlock(); | |
80c3a6ce | 134 | |
af11c397 | 135 | return array_sectors; |
80c3a6ce DW |
136 | } |
137 | ||
7c7546cc | 138 | static linear_conf_t *linear_conf(mddev_t *mddev, int raid_disks) |
1da177e4 LT |
139 | { |
140 | linear_conf_t *conf; | |
1da177e4 | 141 | mdk_rdev_t *rdev; |
45d4582f | 142 | int i, cnt; |
1da177e4 | 143 | |
7c7546cc | 144 | conf = kzalloc (sizeof (*conf) + raid_disks*sizeof(dev_info_t), |
1da177e4 LT |
145 | GFP_KERNEL); |
146 | if (!conf) | |
7c7546cc N |
147 | return NULL; |
148 | ||
1da177e4 | 149 | cnt = 0; |
d6e22150 | 150 | conf->array_sectors = 0; |
1da177e4 | 151 | |
159ec1fc | 152 | list_for_each_entry(rdev, &mddev->disks, same_set) { |
1da177e4 LT |
153 | int j = rdev->raid_disk; |
154 | dev_info_t *disk = conf->disks + j; | |
13f2682b | 155 | sector_t sectors; |
1da177e4 | 156 | |
13864515 | 157 | if (j < 0 || j >= raid_disks || disk->rdev) { |
1da177e4 LT |
158 | printk("linear: disk numbering problem. Aborting!\n"); |
159 | goto out; | |
160 | } | |
161 | ||
162 | disk->rdev = rdev; | |
13f2682b N |
163 | if (mddev->chunk_sectors) { |
164 | sectors = rdev->sectors; | |
165 | sector_div(sectors, mddev->chunk_sectors); | |
166 | rdev->sectors = sectors * mddev->chunk_sectors; | |
167 | } | |
1da177e4 | 168 | |
8f6c2e4b MP |
169 | disk_stack_limits(mddev->gendisk, rdev->bdev, |
170 | rdev->data_offset << 9); | |
1da177e4 LT |
171 | /* as we don't honour merge_bvec_fn, we must never risk |
172 | * violating it, so limit ->max_sector to one PAGE, as | |
173 | * a one page request is never in violation. | |
174 | */ | |
175 | if (rdev->bdev->bd_disk->queue->merge_bvec_fn && | |
ae03bf63 | 176 | queue_max_sectors(mddev->queue) > (PAGE_SIZE>>9)) |
1da177e4 LT |
177 | blk_queue_max_sectors(mddev->queue, PAGE_SIZE>>9); |
178 | ||
dd8ac336 | 179 | conf->array_sectors += rdev->sectors; |
1da177e4 | 180 | cnt++; |
4db7cdc8 | 181 | |
1da177e4 | 182 | } |
7c7546cc | 183 | if (cnt != raid_disks) { |
1da177e4 LT |
184 | printk("linear: not enough drives present. Aborting!\n"); |
185 | goto out; | |
186 | } | |
187 | ||
188 | /* | |
45d4582f | 189 | * Here we calculate the device offsets. |
1da177e4 | 190 | */ |
4db7cdc8 SS |
191 | conf->disks[0].end_sector = conf->disks[0].rdev->sectors; |
192 | ||
a778b73f | 193 | for (i = 1; i < raid_disks; i++) |
4db7cdc8 SS |
194 | conf->disks[i].end_sector = |
195 | conf->disks[i-1].end_sector + | |
196 | conf->disks[i].rdev->sectors; | |
15945fee | 197 | |
7c7546cc N |
198 | return conf; |
199 | ||
200 | out: | |
201 | kfree(conf); | |
202 | return NULL; | |
203 | } | |
204 | ||
205 | static int linear_run (mddev_t *mddev) | |
206 | { | |
207 | linear_conf_t *conf; | |
208 | ||
0894cc30 AN |
209 | if (md_check_no_bitmap(mddev)) |
210 | return -EINVAL; | |
e7e72bf6 | 211 | mddev->queue->queue_lock = &mddev->queue->__queue_lock; |
7c7546cc N |
212 | conf = linear_conf(mddev, mddev->raid_disks); |
213 | ||
214 | if (!conf) | |
215 | return 1; | |
216 | mddev->private = conf; | |
1f403624 | 217 | md_set_array_sectors(mddev, linear_size(mddev, 0, 0)); |
7c7546cc | 218 | |
1da177e4 LT |
219 | blk_queue_merge_bvec(mddev->queue, linear_mergeable_bvec); |
220 | mddev->queue->unplug_fn = linear_unplug; | |
26be34dc N |
221 | mddev->queue->backing_dev_info.congested_fn = linear_congested; |
222 | mddev->queue->backing_dev_info.congested_data = mddev; | |
1da177e4 | 223 | return 0; |
7c7546cc | 224 | } |
1da177e4 | 225 | |
495d3573 N |
226 | static void free_conf(struct rcu_head *head) |
227 | { | |
228 | linear_conf_t *conf = container_of(head, linear_conf_t, rcu); | |
229 | kfree(conf); | |
230 | } | |
231 | ||
7c7546cc N |
232 | static int linear_add(mddev_t *mddev, mdk_rdev_t *rdev) |
233 | { | |
234 | /* Adding a drive to a linear array allows the array to grow. | |
235 | * It is permitted if the new drive has a matching superblock | |
236 | * already on it, with raid_disk equal to raid_disks. | |
237 | * It is achieved by creating a new linear_private_data structure | |
238 | * and swapping it in in-place of the current one. | |
239 | * The current one is never freed until the array is stopped. | |
240 | * This avoids races. | |
241 | */ | |
495d3573 | 242 | linear_conf_t *newconf, *oldconf; |
7c7546cc | 243 | |
a778b73f | 244 | if (rdev->saved_raid_disk != mddev->raid_disks) |
7c7546cc N |
245 | return -EINVAL; |
246 | ||
a778b73f N |
247 | rdev->raid_disk = rdev->saved_raid_disk; |
248 | ||
7c7546cc N |
249 | newconf = linear_conf(mddev,mddev->raid_disks+1); |
250 | ||
251 | if (!newconf) | |
252 | return -ENOMEM; | |
253 | ||
495d3573 | 254 | oldconf = rcu_dereference(mddev->private); |
7c7546cc | 255 | mddev->raid_disks++; |
af11c397 | 256 | rcu_assign_pointer(mddev->private, newconf); |
1f403624 | 257 | md_set_array_sectors(mddev, linear_size(mddev, 0, 0)); |
f233ea5c | 258 | set_capacity(mddev->gendisk, mddev->array_sectors); |
495d3573 | 259 | call_rcu(&oldconf->rcu, free_conf); |
7c7546cc | 260 | return 0; |
1da177e4 LT |
261 | } |
262 | ||
263 | static int linear_stop (mddev_t *mddev) | |
264 | { | |
070ec55d | 265 | linear_conf_t *conf = mddev->private; |
af11c397 S |
266 | |
267 | /* | |
268 | * We do not require rcu protection here since | |
269 | * we hold reconfig_mutex for both linear_add and | |
270 | * linear_stop, so they cannot race. | |
495d3573 N |
271 | * We should make sure any old 'conf's are properly |
272 | * freed though. | |
af11c397 | 273 | */ |
495d3573 | 274 | rcu_barrier(); |
1da177e4 | 275 | blk_sync_queue(mddev->queue); /* the unplug fn references 'conf'*/ |
495d3573 | 276 | kfree(conf); |
1da177e4 LT |
277 | |
278 | return 0; | |
279 | } | |
280 | ||
165125e1 | 281 | static int linear_make_request (struct request_queue *q, struct bio *bio) |
1da177e4 | 282 | { |
a362357b | 283 | const int rw = bio_data_dir(bio); |
1da177e4 LT |
284 | mddev_t *mddev = q->queuedata; |
285 | dev_info_t *tmp_dev; | |
4db7cdc8 | 286 | sector_t start_sector; |
c9959059 | 287 | int cpu; |
1da177e4 | 288 | |
e5dcdd80 | 289 | if (unlikely(bio_barrier(bio))) { |
6712ecf8 | 290 | bio_endio(bio, -EOPNOTSUPP); |
e5dcdd80 N |
291 | return 0; |
292 | } | |
293 | ||
074a7aca TH |
294 | cpu = part_stat_lock(); |
295 | part_stat_inc(cpu, &mddev->gendisk->part0, ios[rw]); | |
296 | part_stat_add(cpu, &mddev->gendisk->part0, sectors[rw], | |
297 | bio_sectors(bio)); | |
298 | part_stat_unlock(); | |
1da177e4 | 299 | |
af11c397 | 300 | rcu_read_lock(); |
1da177e4 | 301 | tmp_dev = which_dev(mddev, bio->bi_sector); |
4db7cdc8 SS |
302 | start_sector = tmp_dev->end_sector - tmp_dev->rdev->sectors; |
303 | ||
af11c397 | 304 | |
4db7cdc8 SS |
305 | if (unlikely(bio->bi_sector >= (tmp_dev->end_sector) |
306 | || (bio->bi_sector < start_sector))) { | |
1da177e4 LT |
307 | char b[BDEVNAME_SIZE]; |
308 | ||
6283815d AN |
309 | printk("linear_make_request: Sector %llu out of bounds on " |
310 | "dev %s: %llu sectors, offset %llu\n", | |
311 | (unsigned long long)bio->bi_sector, | |
1da177e4 | 312 | bdevname(tmp_dev->rdev->bdev, b), |
4db7cdc8 SS |
313 | (unsigned long long)tmp_dev->rdev->sectors, |
314 | (unsigned long long)start_sector); | |
af11c397 | 315 | rcu_read_unlock(); |
6712ecf8 | 316 | bio_io_error(bio); |
1da177e4 LT |
317 | return 0; |
318 | } | |
319 | if (unlikely(bio->bi_sector + (bio->bi_size >> 9) > | |
4db7cdc8 | 320 | tmp_dev->end_sector)) { |
1da177e4 LT |
321 | /* This bio crosses a device boundary, so we have to |
322 | * split it. | |
323 | */ | |
324 | struct bio_pair *bp; | |
af11c397 S |
325 | sector_t end_sector = tmp_dev->end_sector; |
326 | ||
327 | rcu_read_unlock(); | |
6283815d | 328 | |
af11c397 | 329 | bp = bio_split(bio, end_sector - bio->bi_sector); |
6283815d | 330 | |
1da177e4 LT |
331 | if (linear_make_request(q, &bp->bio1)) |
332 | generic_make_request(&bp->bio1); | |
333 | if (linear_make_request(q, &bp->bio2)) | |
334 | generic_make_request(&bp->bio2); | |
335 | bio_pair_release(bp); | |
336 | return 0; | |
337 | } | |
338 | ||
339 | bio->bi_bdev = tmp_dev->rdev->bdev; | |
4db7cdc8 | 340 | bio->bi_sector = bio->bi_sector - start_sector |
6283815d | 341 | + tmp_dev->rdev->data_offset; |
af11c397 | 342 | rcu_read_unlock(); |
1da177e4 LT |
343 | |
344 | return 1; | |
345 | } | |
346 | ||
347 | static void linear_status (struct seq_file *seq, mddev_t *mddev) | |
348 | { | |
349 | ||
9d8f0363 | 350 | seq_printf(seq, " %dk rounding", mddev->chunk_sectors / 2); |
1da177e4 LT |
351 | } |
352 | ||
353 | ||
2604b703 | 354 | static struct mdk_personality linear_personality = |
1da177e4 LT |
355 | { |
356 | .name = "linear", | |
2604b703 | 357 | .level = LEVEL_LINEAR, |
1da177e4 LT |
358 | .owner = THIS_MODULE, |
359 | .make_request = linear_make_request, | |
360 | .run = linear_run, | |
361 | .stop = linear_stop, | |
362 | .status = linear_status, | |
7c7546cc | 363 | .hot_add_disk = linear_add, |
80c3a6ce | 364 | .size = linear_size, |
1da177e4 LT |
365 | }; |
366 | ||
367 | static int __init linear_init (void) | |
368 | { | |
2604b703 | 369 | return register_md_personality (&linear_personality); |
1da177e4 LT |
370 | } |
371 | ||
372 | static void linear_exit (void) | |
373 | { | |
2604b703 | 374 | unregister_md_personality (&linear_personality); |
1da177e4 LT |
375 | } |
376 | ||
377 | ||
378 | module_init(linear_init); | |
379 | module_exit(linear_exit); | |
380 | MODULE_LICENSE("GPL"); | |
d9d166c2 N |
381 | MODULE_ALIAS("md-personality-1"); /* LINEAR - deprecated*/ |
382 | MODULE_ALIAS("md-linear"); | |
2604b703 | 383 | MODULE_ALIAS("md-level--1"); |