Commit | Line | Data |
---|---|---|
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> |
056075c7 | 22 | #include <linux/module.h> |
5a0e3ad6 | 23 | #include <linux/slab.h> |
43b2e5d8 | 24 | #include "md.h" |
ef740c37 | 25 | #include "linear.h" |
1da177e4 | 26 | |
1da177e4 LT |
27 | /* |
28 | * find which device holds a particular offset | |
29 | */ | |
a7120771 | 30 | static inline struct dev_info *which_dev(struct mddev *mddev, sector_t sector) |
1da177e4 | 31 | { |
aece3d1f | 32 | int lo, mid, hi; |
e849b938 | 33 | struct linear_conf *conf; |
1da177e4 | 34 | |
aece3d1f SS |
35 | lo = 0; |
36 | hi = mddev->raid_disks - 1; | |
af11c397 | 37 | conf = rcu_dereference(mddev->private); |
1da177e4 | 38 | |
aece3d1f SS |
39 | /* |
40 | * Binary Search | |
41 | */ | |
42 | ||
43 | while (hi > lo) { | |
44 | ||
45 | mid = (hi + lo) / 2; | |
46 | if (sector < conf->disks[mid].end_sector) | |
47 | hi = mid; | |
48 | else | |
49 | lo = mid + 1; | |
50 | } | |
51 | ||
52 | return conf->disks + lo; | |
1da177e4 LT |
53 | } |
54 | ||
55 | /** | |
15945fee | 56 | * linear_mergeable_bvec -- tell bio layer if two requests can be merged |
1da177e4 | 57 | * @q: request queue |
cc371e66 | 58 | * @bvm: properties of new bio |
1da177e4 LT |
59 | * @biovec: the request that could be merged to it. |
60 | * | |
61 | * Return amount of bytes we can take at this offset | |
62 | */ | |
cc371e66 AK |
63 | static int linear_mergeable_bvec(struct request_queue *q, |
64 | struct bvec_merge_data *bvm, | |
65 | struct bio_vec *biovec) | |
1da177e4 | 66 | { |
fd01b88c | 67 | struct mddev *mddev = q->queuedata; |
a7120771 | 68 | struct dev_info *dev0; |
cc371e66 AK |
69 | unsigned long maxsectors, bio_sectors = bvm->bi_size >> 9; |
70 | sector_t sector = bvm->bi_sector + get_start_sect(bvm->bi_bdev); | |
ba13da47 N |
71 | int maxbytes = biovec->bv_len; |
72 | struct request_queue *subq; | |
1da177e4 | 73 | |
af11c397 | 74 | rcu_read_lock(); |
1da177e4 | 75 | dev0 = which_dev(mddev, sector); |
4db7cdc8 | 76 | maxsectors = dev0->end_sector - sector; |
ba13da47 N |
77 | subq = bdev_get_queue(dev0->rdev->bdev); |
78 | if (subq->merge_bvec_fn) { | |
79 | bvm->bi_bdev = dev0->rdev->bdev; | |
80 | bvm->bi_sector -= dev0->end_sector - dev0->rdev->sectors; | |
81 | maxbytes = min(maxbytes, subq->merge_bvec_fn(subq, bvm, | |
82 | biovec)); | |
83 | } | |
af11c397 | 84 | rcu_read_unlock(); |
1da177e4 LT |
85 | |
86 | if (maxsectors < bio_sectors) | |
87 | maxsectors = 0; | |
88 | else | |
89 | maxsectors -= bio_sectors; | |
90 | ||
91 | if (maxsectors <= (PAGE_SIZE >> 9 ) && bio_sectors == 0) | |
ba13da47 N |
92 | return maxbytes; |
93 | ||
94 | if (maxsectors > (maxbytes >> 9)) | |
95 | return maxbytes; | |
96 | else | |
97 | return maxsectors << 9; | |
1da177e4 LT |
98 | } |
99 | ||
26be34dc N |
100 | static int linear_congested(void *data, int bits) |
101 | { | |
fd01b88c | 102 | struct mddev *mddev = data; |
e849b938 | 103 | struct linear_conf *conf; |
26be34dc N |
104 | int i, ret = 0; |
105 | ||
3fa841d7 N |
106 | if (mddev_congested(mddev, bits)) |
107 | return 1; | |
108 | ||
af11c397 S |
109 | rcu_read_lock(); |
110 | conf = rcu_dereference(mddev->private); | |
111 | ||
26be34dc | 112 | for (i = 0; i < mddev->raid_disks && !ret ; i++) { |
165125e1 | 113 | struct request_queue *q = bdev_get_queue(conf->disks[i].rdev->bdev); |
26be34dc N |
114 | ret |= bdi_congested(&q->backing_dev_info, bits); |
115 | } | |
af11c397 S |
116 | |
117 | rcu_read_unlock(); | |
26be34dc N |
118 | return ret; |
119 | } | |
120 | ||
fd01b88c | 121 | static sector_t linear_size(struct mddev *mddev, sector_t sectors, int raid_disks) |
80c3a6ce | 122 | { |
e849b938 | 123 | struct linear_conf *conf; |
af11c397 | 124 | sector_t array_sectors; |
80c3a6ce | 125 | |
af11c397 S |
126 | rcu_read_lock(); |
127 | conf = rcu_dereference(mddev->private); | |
80c3a6ce DW |
128 | WARN_ONCE(sectors || raid_disks, |
129 | "%s does not support generic reshape\n", __func__); | |
af11c397 S |
130 | array_sectors = conf->array_sectors; |
131 | rcu_read_unlock(); | |
80c3a6ce | 132 | |
af11c397 | 133 | return array_sectors; |
80c3a6ce DW |
134 | } |
135 | ||
e849b938 | 136 | static struct linear_conf *linear_conf(struct mddev *mddev, int raid_disks) |
1da177e4 | 137 | { |
e849b938 | 138 | struct linear_conf *conf; |
3cb03002 | 139 | struct md_rdev *rdev; |
45d4582f | 140 | int i, cnt; |
f1cad2b6 | 141 | bool discard_supported = false; |
1da177e4 | 142 | |
a7120771 | 143 | conf = kzalloc (sizeof (*conf) + raid_disks*sizeof(struct dev_info), |
1da177e4 LT |
144 | GFP_KERNEL); |
145 | if (!conf) | |
7c7546cc N |
146 | return NULL; |
147 | ||
1da177e4 | 148 | cnt = 0; |
d6e22150 | 149 | conf->array_sectors = 0; |
1da177e4 | 150 | |
dafb20fa | 151 | rdev_for_each(rdev, mddev) { |
1da177e4 | 152 | int j = rdev->raid_disk; |
a7120771 | 153 | struct dev_info *disk = conf->disks + j; |
13f2682b | 154 | sector_t sectors; |
1da177e4 | 155 | |
13864515 | 156 | if (j < 0 || j >= raid_disks || disk->rdev) { |
2dc40f80 N |
157 | printk(KERN_ERR "md/linear:%s: disk numbering problem. Aborting!\n", |
158 | mdname(mddev)); | |
1da177e4 LT |
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 | 171 | |
dd8ac336 | 172 | conf->array_sectors += rdev->sectors; |
1da177e4 | 173 | cnt++; |
4db7cdc8 | 174 | |
f1cad2b6 SL |
175 | if (blk_queue_discard(bdev_get_queue(rdev->bdev))) |
176 | discard_supported = true; | |
1da177e4 | 177 | } |
7c7546cc | 178 | if (cnt != raid_disks) { |
2dc40f80 N |
179 | printk(KERN_ERR "md/linear:%s: not enough drives present. Aborting!\n", |
180 | mdname(mddev)); | |
1da177e4 LT |
181 | goto out; |
182 | } | |
183 | ||
f1cad2b6 SL |
184 | if (!discard_supported) |
185 | queue_flag_clear_unlocked(QUEUE_FLAG_DISCARD, mddev->queue); | |
186 | else | |
187 | queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, mddev->queue); | |
188 | ||
1da177e4 | 189 | /* |
45d4582f | 190 | * Here we calculate the device offsets. |
1da177e4 | 191 | */ |
4db7cdc8 SS |
192 | conf->disks[0].end_sector = conf->disks[0].rdev->sectors; |
193 | ||
a778b73f | 194 | for (i = 1; i < raid_disks; i++) |
4db7cdc8 SS |
195 | conf->disks[i].end_sector = |
196 | conf->disks[i-1].end_sector + | |
197 | conf->disks[i].rdev->sectors; | |
15945fee | 198 | |
7c7546cc N |
199 | return conf; |
200 | ||
201 | out: | |
202 | kfree(conf); | |
203 | return NULL; | |
204 | } | |
205 | ||
fd01b88c | 206 | static int linear_run (struct mddev *mddev) |
7c7546cc | 207 | { |
e849b938 | 208 | struct linear_conf *conf; |
98d5561b | 209 | int ret; |
7c7546cc | 210 | |
0894cc30 AN |
211 | if (md_check_no_bitmap(mddev)) |
212 | return -EINVAL; | |
7c7546cc N |
213 | conf = linear_conf(mddev, mddev->raid_disks); |
214 | ||
215 | if (!conf) | |
216 | return 1; | |
217 | mddev->private = conf; | |
1f403624 | 218 | md_set_array_sectors(mddev, linear_size(mddev, 0, 0)); |
7c7546cc | 219 | |
1da177e4 | 220 | blk_queue_merge_bvec(mddev->queue, linear_mergeable_bvec); |
26be34dc N |
221 | mddev->queue->backing_dev_info.congested_fn = linear_congested; |
222 | mddev->queue->backing_dev_info.congested_data = mddev; | |
98d5561b | 223 | |
224 | ret = md_integrity_register(mddev); | |
225 | if (ret) { | |
226 | kfree(conf); | |
227 | mddev->private = NULL; | |
228 | } | |
229 | return ret; | |
7c7546cc | 230 | } |
1da177e4 | 231 | |
fd01b88c | 232 | static int linear_add(struct mddev *mddev, struct md_rdev *rdev) |
7c7546cc N |
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 | */ | |
e849b938 | 242 | struct linear_conf *newconf, *oldconf; |
7c7546cc | 243 | |
a778b73f | 244 | if (rdev->saved_raid_disk != mddev->raid_disks) |
7c7546cc N |
245 | return -EINVAL; |
246 | ||
a778b73f | 247 | rdev->raid_disk = rdev->saved_raid_disk; |
09cd9270 | 248 | rdev->saved_raid_disk = -1; |
a778b73f | 249 | |
7c7546cc N |
250 | newconf = linear_conf(mddev,mddev->raid_disks+1); |
251 | ||
252 | if (!newconf) | |
253 | return -ENOMEM; | |
254 | ||
bc78c573 DE |
255 | oldconf = rcu_dereference_protected(mddev->private, |
256 | lockdep_is_held( | |
257 | &mddev->reconfig_mutex)); | |
7c7546cc | 258 | mddev->raid_disks++; |
af11c397 | 259 | rcu_assign_pointer(mddev->private, newconf); |
1f403624 | 260 | md_set_array_sectors(mddev, linear_size(mddev, 0, 0)); |
f233ea5c | 261 | set_capacity(mddev->gendisk, mddev->array_sectors); |
449aad3e | 262 | revalidate_disk(mddev->gendisk); |
b119cbab | 263 | kfree_rcu(oldconf, rcu); |
7c7546cc | 264 | return 0; |
1da177e4 LT |
265 | } |
266 | ||
fd01b88c | 267 | static int linear_stop (struct mddev *mddev) |
1da177e4 | 268 | { |
bc78c573 DE |
269 | struct linear_conf *conf = |
270 | rcu_dereference_protected(mddev->private, | |
271 | lockdep_is_held( | |
272 | &mddev->reconfig_mutex)); | |
af11c397 S |
273 | |
274 | /* | |
275 | * We do not require rcu protection here since | |
276 | * we hold reconfig_mutex for both linear_add and | |
277 | * linear_stop, so they cannot race. | |
495d3573 N |
278 | * We should make sure any old 'conf's are properly |
279 | * freed though. | |
af11c397 | 280 | */ |
495d3573 | 281 | rcu_barrier(); |
1da177e4 | 282 | blk_sync_queue(mddev->queue); /* the unplug fn references 'conf'*/ |
495d3573 | 283 | kfree(conf); |
ef2f80ff | 284 | mddev->private = NULL; |
1da177e4 LT |
285 | |
286 | return 0; | |
287 | } | |
288 | ||
b4fdcb02 | 289 | static void linear_make_request(struct mddev *mddev, struct bio *bio) |
1da177e4 | 290 | { |
20d0189b | 291 | char b[BDEVNAME_SIZE]; |
a7120771 | 292 | struct dev_info *tmp_dev; |
20d0189b KO |
293 | struct bio *split; |
294 | sector_t start_sector, end_sector, data_offset; | |
1da177e4 | 295 | |
e9c7469b TH |
296 | if (unlikely(bio->bi_rw & REQ_FLUSH)) { |
297 | md_flush_request(mddev, bio); | |
5a7bbad2 | 298 | return; |
e5dcdd80 N |
299 | } |
300 | ||
20d0189b KO |
301 | do { |
302 | rcu_read_lock(); | |
af11c397 | 303 | |
20d0189b KO |
304 | tmp_dev = which_dev(mddev, bio->bi_iter.bi_sector); |
305 | start_sector = tmp_dev->end_sector - tmp_dev->rdev->sectors; | |
306 | end_sector = tmp_dev->end_sector; | |
307 | data_offset = tmp_dev->rdev->data_offset; | |
308 | bio->bi_bdev = tmp_dev->rdev->bdev; | |
6283815d | 309 | |
20d0189b | 310 | rcu_read_unlock(); |
f1cad2b6 | 311 | |
20d0189b KO |
312 | if (unlikely(bio->bi_iter.bi_sector >= end_sector || |
313 | bio->bi_iter.bi_sector < start_sector)) | |
314 | goto out_of_bounds; | |
315 | ||
316 | if (unlikely(bio_end_sector(bio) > end_sector)) { | |
317 | /* This bio crosses a device boundary, so we have to | |
318 | * split it. | |
319 | */ | |
320 | split = bio_split(bio, end_sector - | |
321 | bio->bi_iter.bi_sector, | |
322 | GFP_NOIO, fs_bio_set); | |
323 | bio_chain(split, bio); | |
324 | } else { | |
325 | split = bio; | |
326 | } | |
f1cad2b6 | 327 | |
20d0189b KO |
328 | split->bi_iter.bi_sector = split->bi_iter.bi_sector - |
329 | start_sector + data_offset; | |
330 | ||
331 | if (unlikely((split->bi_rw & REQ_DISCARD) && | |
332 | !blk_queue_discard(bdev_get_queue(split->bi_bdev)))) { | |
333 | /* Just ignore it */ | |
334 | bio_endio(split, 0); | |
335 | } else | |
336 | generic_make_request(split); | |
337 | } while (split != bio); | |
338 | return; | |
339 | ||
340 | out_of_bounds: | |
341 | printk(KERN_ERR | |
342 | "md/linear:%s: make_request: Sector %llu out of bounds on " | |
343 | "dev %s: %llu sectors, offset %llu\n", | |
344 | mdname(mddev), | |
345 | (unsigned long long)bio->bi_iter.bi_sector, | |
346 | bdevname(tmp_dev->rdev->bdev, b), | |
347 | (unsigned long long)tmp_dev->rdev->sectors, | |
348 | (unsigned long long)start_sector); | |
349 | bio_io_error(bio); | |
1da177e4 LT |
350 | } |
351 | ||
fd01b88c | 352 | static void linear_status (struct seq_file *seq, struct mddev *mddev) |
1da177e4 LT |
353 | { |
354 | ||
9d8f0363 | 355 | seq_printf(seq, " %dk rounding", mddev->chunk_sectors / 2); |
1da177e4 LT |
356 | } |
357 | ||
358 | ||
84fc4b56 | 359 | static struct md_personality linear_personality = |
1da177e4 LT |
360 | { |
361 | .name = "linear", | |
2604b703 | 362 | .level = LEVEL_LINEAR, |
1da177e4 LT |
363 | .owner = THIS_MODULE, |
364 | .make_request = linear_make_request, | |
365 | .run = linear_run, | |
366 | .stop = linear_stop, | |
367 | .status = linear_status, | |
7c7546cc | 368 | .hot_add_disk = linear_add, |
80c3a6ce | 369 | .size = linear_size, |
1da177e4 LT |
370 | }; |
371 | ||
372 | static int __init linear_init (void) | |
373 | { | |
2604b703 | 374 | return register_md_personality (&linear_personality); |
1da177e4 LT |
375 | } |
376 | ||
377 | static void linear_exit (void) | |
378 | { | |
2604b703 | 379 | unregister_md_personality (&linear_personality); |
1da177e4 LT |
380 | } |
381 | ||
382 | ||
383 | module_init(linear_init); | |
384 | module_exit(linear_exit); | |
385 | MODULE_LICENSE("GPL"); | |
0efb9e61 | 386 | MODULE_DESCRIPTION("Linear device concatenation personality for MD"); |
d9d166c2 N |
387 | MODULE_ALIAS("md-personality-1"); /* LINEAR - deprecated*/ |
388 | MODULE_ALIAS("md-linear"); | |
2604b703 | 389 | MODULE_ALIAS("md-level--1"); |