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. | |
f72ffdd6 | 13 | |
1da177e4 LT |
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 | |
f72ffdd6 | 16 | Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. |
1da177e4 LT |
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 | 27 | /* |
f72ffdd6 | 28 | * find which device holds a particular offset |
1da177e4 | 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 | */ | |
64590f45 | 63 | static int linear_mergeable_bvec(struct mddev *mddev, |
cc371e66 AK |
64 | struct bvec_merge_data *bvm, |
65 | struct bio_vec *biovec) | |
1da177e4 | 66 | { |
a7120771 | 67 | struct dev_info *dev0; |
cc371e66 AK |
68 | unsigned long maxsectors, bio_sectors = bvm->bi_size >> 9; |
69 | sector_t sector = bvm->bi_sector + get_start_sect(bvm->bi_bdev); | |
ba13da47 N |
70 | int maxbytes = biovec->bv_len; |
71 | struct request_queue *subq; | |
1da177e4 | 72 | |
af11c397 | 73 | rcu_read_lock(); |
1da177e4 | 74 | dev0 = which_dev(mddev, sector); |
4db7cdc8 | 75 | maxsectors = dev0->end_sector - sector; |
ba13da47 N |
76 | subq = bdev_get_queue(dev0->rdev->bdev); |
77 | if (subq->merge_bvec_fn) { | |
78 | bvm->bi_bdev = dev0->rdev->bdev; | |
79 | bvm->bi_sector -= dev0->end_sector - dev0->rdev->sectors; | |
80 | maxbytes = min(maxbytes, subq->merge_bvec_fn(subq, bvm, | |
81 | biovec)); | |
82 | } | |
af11c397 | 83 | rcu_read_unlock(); |
1da177e4 LT |
84 | |
85 | if (maxsectors < bio_sectors) | |
86 | maxsectors = 0; | |
87 | else | |
88 | maxsectors -= bio_sectors; | |
89 | ||
90 | if (maxsectors <= (PAGE_SIZE >> 9 ) && bio_sectors == 0) | |
ba13da47 N |
91 | return maxbytes; |
92 | ||
93 | if (maxsectors > (maxbytes >> 9)) | |
94 | return maxbytes; | |
95 | else | |
96 | return maxsectors << 9; | |
1da177e4 LT |
97 | } |
98 | ||
5c675f83 | 99 | static int linear_congested(struct mddev *mddev, int bits) |
26be34dc | 100 | { |
e849b938 | 101 | struct linear_conf *conf; |
26be34dc N |
102 | int i, ret = 0; |
103 | ||
af11c397 S |
104 | rcu_read_lock(); |
105 | conf = rcu_dereference(mddev->private); | |
106 | ||
26be34dc | 107 | for (i = 0; i < mddev->raid_disks && !ret ; i++) { |
165125e1 | 108 | struct request_queue *q = bdev_get_queue(conf->disks[i].rdev->bdev); |
26be34dc N |
109 | ret |= bdi_congested(&q->backing_dev_info, bits); |
110 | } | |
af11c397 S |
111 | |
112 | rcu_read_unlock(); | |
26be34dc N |
113 | return ret; |
114 | } | |
115 | ||
fd01b88c | 116 | static sector_t linear_size(struct mddev *mddev, sector_t sectors, int raid_disks) |
80c3a6ce | 117 | { |
e849b938 | 118 | struct linear_conf *conf; |
af11c397 | 119 | sector_t array_sectors; |
80c3a6ce | 120 | |
af11c397 S |
121 | rcu_read_lock(); |
122 | conf = rcu_dereference(mddev->private); | |
80c3a6ce DW |
123 | WARN_ONCE(sectors || raid_disks, |
124 | "%s does not support generic reshape\n", __func__); | |
af11c397 S |
125 | array_sectors = conf->array_sectors; |
126 | rcu_read_unlock(); | |
80c3a6ce | 127 | |
af11c397 | 128 | return array_sectors; |
80c3a6ce DW |
129 | } |
130 | ||
e849b938 | 131 | static struct linear_conf *linear_conf(struct mddev *mddev, int raid_disks) |
1da177e4 | 132 | { |
e849b938 | 133 | struct linear_conf *conf; |
3cb03002 | 134 | struct md_rdev *rdev; |
45d4582f | 135 | int i, cnt; |
f1cad2b6 | 136 | bool discard_supported = false; |
1da177e4 | 137 | |
a7120771 | 138 | conf = kzalloc (sizeof (*conf) + raid_disks*sizeof(struct dev_info), |
1da177e4 LT |
139 | GFP_KERNEL); |
140 | if (!conf) | |
7c7546cc N |
141 | return NULL; |
142 | ||
1da177e4 | 143 | cnt = 0; |
d6e22150 | 144 | conf->array_sectors = 0; |
1da177e4 | 145 | |
dafb20fa | 146 | rdev_for_each(rdev, mddev) { |
1da177e4 | 147 | int j = rdev->raid_disk; |
a7120771 | 148 | struct dev_info *disk = conf->disks + j; |
13f2682b | 149 | sector_t sectors; |
1da177e4 | 150 | |
13864515 | 151 | if (j < 0 || j >= raid_disks || disk->rdev) { |
2dc40f80 N |
152 | printk(KERN_ERR "md/linear:%s: disk numbering problem. Aborting!\n", |
153 | mdname(mddev)); | |
1da177e4 LT |
154 | goto out; |
155 | } | |
156 | ||
157 | disk->rdev = rdev; | |
13f2682b N |
158 | if (mddev->chunk_sectors) { |
159 | sectors = rdev->sectors; | |
160 | sector_div(sectors, mddev->chunk_sectors); | |
161 | rdev->sectors = sectors * mddev->chunk_sectors; | |
162 | } | |
1da177e4 | 163 | |
8f6c2e4b MP |
164 | disk_stack_limits(mddev->gendisk, rdev->bdev, |
165 | rdev->data_offset << 9); | |
1da177e4 | 166 | |
dd8ac336 | 167 | conf->array_sectors += rdev->sectors; |
1da177e4 | 168 | cnt++; |
4db7cdc8 | 169 | |
f1cad2b6 SL |
170 | if (blk_queue_discard(bdev_get_queue(rdev->bdev))) |
171 | discard_supported = true; | |
1da177e4 | 172 | } |
7c7546cc | 173 | if (cnt != raid_disks) { |
2dc40f80 N |
174 | printk(KERN_ERR "md/linear:%s: not enough drives present. Aborting!\n", |
175 | mdname(mddev)); | |
1da177e4 LT |
176 | goto out; |
177 | } | |
178 | ||
f1cad2b6 SL |
179 | if (!discard_supported) |
180 | queue_flag_clear_unlocked(QUEUE_FLAG_DISCARD, mddev->queue); | |
181 | else | |
182 | queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, mddev->queue); | |
183 | ||
1da177e4 | 184 | /* |
45d4582f | 185 | * Here we calculate the device offsets. |
1da177e4 | 186 | */ |
4db7cdc8 SS |
187 | conf->disks[0].end_sector = conf->disks[0].rdev->sectors; |
188 | ||
a778b73f | 189 | for (i = 1; i < raid_disks; i++) |
4db7cdc8 SS |
190 | conf->disks[i].end_sector = |
191 | conf->disks[i-1].end_sector + | |
192 | conf->disks[i].rdev->sectors; | |
15945fee | 193 | |
7c7546cc N |
194 | return conf; |
195 | ||
196 | out: | |
197 | kfree(conf); | |
198 | return NULL; | |
199 | } | |
200 | ||
fd01b88c | 201 | static int linear_run (struct mddev *mddev) |
7c7546cc | 202 | { |
e849b938 | 203 | struct linear_conf *conf; |
98d5561b | 204 | int ret; |
7c7546cc | 205 | |
0894cc30 AN |
206 | if (md_check_no_bitmap(mddev)) |
207 | return -EINVAL; | |
7c7546cc N |
208 | conf = linear_conf(mddev, mddev->raid_disks); |
209 | ||
210 | if (!conf) | |
211 | return 1; | |
212 | mddev->private = conf; | |
1f403624 | 213 | md_set_array_sectors(mddev, linear_size(mddev, 0, 0)); |
7c7546cc | 214 | |
98d5561b | 215 | ret = md_integrity_register(mddev); |
216 | if (ret) { | |
217 | kfree(conf); | |
218 | mddev->private = NULL; | |
219 | } | |
220 | return ret; | |
7c7546cc | 221 | } |
1da177e4 | 222 | |
fd01b88c | 223 | static int linear_add(struct mddev *mddev, struct md_rdev *rdev) |
7c7546cc N |
224 | { |
225 | /* Adding a drive to a linear array allows the array to grow. | |
226 | * It is permitted if the new drive has a matching superblock | |
227 | * already on it, with raid_disk equal to raid_disks. | |
228 | * It is achieved by creating a new linear_private_data structure | |
229 | * and swapping it in in-place of the current one. | |
230 | * The current one is never freed until the array is stopped. | |
231 | * This avoids races. | |
232 | */ | |
e849b938 | 233 | struct linear_conf *newconf, *oldconf; |
7c7546cc | 234 | |
a778b73f | 235 | if (rdev->saved_raid_disk != mddev->raid_disks) |
7c7546cc N |
236 | return -EINVAL; |
237 | ||
a778b73f | 238 | rdev->raid_disk = rdev->saved_raid_disk; |
09cd9270 | 239 | rdev->saved_raid_disk = -1; |
a778b73f | 240 | |
7c7546cc N |
241 | newconf = linear_conf(mddev,mddev->raid_disks+1); |
242 | ||
243 | if (!newconf) | |
244 | return -ENOMEM; | |
245 | ||
bc78c573 DE |
246 | oldconf = rcu_dereference_protected(mddev->private, |
247 | lockdep_is_held( | |
248 | &mddev->reconfig_mutex)); | |
7c7546cc | 249 | mddev->raid_disks++; |
af11c397 | 250 | rcu_assign_pointer(mddev->private, newconf); |
1f403624 | 251 | md_set_array_sectors(mddev, linear_size(mddev, 0, 0)); |
f233ea5c | 252 | set_capacity(mddev->gendisk, mddev->array_sectors); |
449aad3e | 253 | revalidate_disk(mddev->gendisk); |
b119cbab | 254 | kfree_rcu(oldconf, rcu); |
7c7546cc | 255 | return 0; |
1da177e4 LT |
256 | } |
257 | ||
fd01b88c | 258 | static int linear_stop (struct mddev *mddev) |
1da177e4 | 259 | { |
bc78c573 DE |
260 | struct linear_conf *conf = |
261 | rcu_dereference_protected(mddev->private, | |
262 | lockdep_is_held( | |
263 | &mddev->reconfig_mutex)); | |
af11c397 S |
264 | |
265 | /* | |
266 | * We do not require rcu protection here since | |
267 | * we hold reconfig_mutex for both linear_add and | |
268 | * linear_stop, so they cannot race. | |
495d3573 N |
269 | * We should make sure any old 'conf's are properly |
270 | * freed though. | |
af11c397 | 271 | */ |
495d3573 | 272 | rcu_barrier(); |
1da177e4 | 273 | blk_sync_queue(mddev->queue); /* the unplug fn references 'conf'*/ |
495d3573 | 274 | kfree(conf); |
ef2f80ff | 275 | mddev->private = NULL; |
1da177e4 LT |
276 | |
277 | return 0; | |
278 | } | |
279 | ||
b4fdcb02 | 280 | static void linear_make_request(struct mddev *mddev, struct bio *bio) |
1da177e4 | 281 | { |
20d0189b | 282 | char b[BDEVNAME_SIZE]; |
a7120771 | 283 | struct dev_info *tmp_dev; |
20d0189b KO |
284 | struct bio *split; |
285 | sector_t start_sector, end_sector, data_offset; | |
1da177e4 | 286 | |
e9c7469b TH |
287 | if (unlikely(bio->bi_rw & REQ_FLUSH)) { |
288 | md_flush_request(mddev, bio); | |
5a7bbad2 | 289 | return; |
e5dcdd80 N |
290 | } |
291 | ||
20d0189b KO |
292 | do { |
293 | rcu_read_lock(); | |
af11c397 | 294 | |
20d0189b KO |
295 | tmp_dev = which_dev(mddev, bio->bi_iter.bi_sector); |
296 | start_sector = tmp_dev->end_sector - tmp_dev->rdev->sectors; | |
297 | end_sector = tmp_dev->end_sector; | |
298 | data_offset = tmp_dev->rdev->data_offset; | |
299 | bio->bi_bdev = tmp_dev->rdev->bdev; | |
6283815d | 300 | |
20d0189b | 301 | rcu_read_unlock(); |
f1cad2b6 | 302 | |
20d0189b KO |
303 | if (unlikely(bio->bi_iter.bi_sector >= end_sector || |
304 | bio->bi_iter.bi_sector < start_sector)) | |
305 | goto out_of_bounds; | |
306 | ||
307 | if (unlikely(bio_end_sector(bio) > end_sector)) { | |
308 | /* This bio crosses a device boundary, so we have to | |
309 | * split it. | |
310 | */ | |
311 | split = bio_split(bio, end_sector - | |
312 | bio->bi_iter.bi_sector, | |
313 | GFP_NOIO, fs_bio_set); | |
314 | bio_chain(split, bio); | |
315 | } else { | |
316 | split = bio; | |
317 | } | |
f1cad2b6 | 318 | |
20d0189b KO |
319 | split->bi_iter.bi_sector = split->bi_iter.bi_sector - |
320 | start_sector + data_offset; | |
321 | ||
322 | if (unlikely((split->bi_rw & REQ_DISCARD) && | |
323 | !blk_queue_discard(bdev_get_queue(split->bi_bdev)))) { | |
324 | /* Just ignore it */ | |
325 | bio_endio(split, 0); | |
326 | } else | |
327 | generic_make_request(split); | |
328 | } while (split != bio); | |
329 | return; | |
330 | ||
331 | out_of_bounds: | |
332 | printk(KERN_ERR | |
333 | "md/linear:%s: make_request: Sector %llu out of bounds on " | |
334 | "dev %s: %llu sectors, offset %llu\n", | |
335 | mdname(mddev), | |
336 | (unsigned long long)bio->bi_iter.bi_sector, | |
337 | bdevname(tmp_dev->rdev->bdev, b), | |
338 | (unsigned long long)tmp_dev->rdev->sectors, | |
339 | (unsigned long long)start_sector); | |
340 | bio_io_error(bio); | |
1da177e4 LT |
341 | } |
342 | ||
fd01b88c | 343 | static void linear_status (struct seq_file *seq, struct mddev *mddev) |
1da177e4 LT |
344 | { |
345 | ||
9d8f0363 | 346 | seq_printf(seq, " %dk rounding", mddev->chunk_sectors / 2); |
1da177e4 LT |
347 | } |
348 | ||
84fc4b56 | 349 | static struct md_personality linear_personality = |
1da177e4 LT |
350 | { |
351 | .name = "linear", | |
2604b703 | 352 | .level = LEVEL_LINEAR, |
1da177e4 LT |
353 | .owner = THIS_MODULE, |
354 | .make_request = linear_make_request, | |
355 | .run = linear_run, | |
356 | .stop = linear_stop, | |
357 | .status = linear_status, | |
7c7546cc | 358 | .hot_add_disk = linear_add, |
80c3a6ce | 359 | .size = linear_size, |
5c675f83 | 360 | .congested = linear_congested, |
64590f45 | 361 | .mergeable_bvec = linear_mergeable_bvec, |
1da177e4 LT |
362 | }; |
363 | ||
364 | static int __init linear_init (void) | |
365 | { | |
2604b703 | 366 | return register_md_personality (&linear_personality); |
1da177e4 LT |
367 | } |
368 | ||
369 | static void linear_exit (void) | |
370 | { | |
2604b703 | 371 | unregister_md_personality (&linear_personality); |
1da177e4 LT |
372 | } |
373 | ||
1da177e4 LT |
374 | module_init(linear_init); |
375 | module_exit(linear_exit); | |
376 | MODULE_LICENSE("GPL"); | |
0efb9e61 | 377 | MODULE_DESCRIPTION("Linear device concatenation personality for MD"); |
d9d166c2 N |
378 | MODULE_ALIAS("md-personality-1"); /* LINEAR - deprecated*/ |
379 | MODULE_ALIAS("md-linear"); | |
2604b703 | 380 | MODULE_ALIAS("md-level--1"); |