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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> |
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; |
1da177e4 | 141 | |
a7120771 | 142 | conf = kzalloc (sizeof (*conf) + raid_disks*sizeof(struct dev_info), |
1da177e4 LT |
143 | GFP_KERNEL); |
144 | if (!conf) | |
7c7546cc N |
145 | return NULL; |
146 | ||
1da177e4 | 147 | cnt = 0; |
d6e22150 | 148 | conf->array_sectors = 0; |
1da177e4 | 149 | |
dafb20fa | 150 | rdev_for_each(rdev, mddev) { |
1da177e4 | 151 | int j = rdev->raid_disk; |
a7120771 | 152 | struct dev_info *disk = conf->disks + j; |
13f2682b | 153 | sector_t sectors; |
1da177e4 | 154 | |
13864515 | 155 | if (j < 0 || j >= raid_disks || disk->rdev) { |
2dc40f80 N |
156 | printk(KERN_ERR "md/linear:%s: disk numbering problem. Aborting!\n", |
157 | mdname(mddev)); | |
1da177e4 LT |
158 | goto out; |
159 | } | |
160 | ||
161 | disk->rdev = rdev; | |
13f2682b N |
162 | if (mddev->chunk_sectors) { |
163 | sectors = rdev->sectors; | |
164 | sector_div(sectors, mddev->chunk_sectors); | |
165 | rdev->sectors = sectors * mddev->chunk_sectors; | |
166 | } | |
1da177e4 | 167 | |
8f6c2e4b MP |
168 | disk_stack_limits(mddev->gendisk, rdev->bdev, |
169 | rdev->data_offset << 9); | |
1da177e4 | 170 | |
dd8ac336 | 171 | conf->array_sectors += rdev->sectors; |
1da177e4 | 172 | cnt++; |
4db7cdc8 | 173 | |
1da177e4 | 174 | } |
7c7546cc | 175 | if (cnt != raid_disks) { |
2dc40f80 N |
176 | printk(KERN_ERR "md/linear:%s: not enough drives present. Aborting!\n", |
177 | mdname(mddev)); | |
1da177e4 LT |
178 | goto out; |
179 | } | |
180 | ||
181 | /* | |
45d4582f | 182 | * Here we calculate the device offsets. |
1da177e4 | 183 | */ |
4db7cdc8 SS |
184 | conf->disks[0].end_sector = conf->disks[0].rdev->sectors; |
185 | ||
a778b73f | 186 | for (i = 1; i < raid_disks; i++) |
4db7cdc8 SS |
187 | conf->disks[i].end_sector = |
188 | conf->disks[i-1].end_sector + | |
189 | conf->disks[i].rdev->sectors; | |
15945fee | 190 | |
7c7546cc N |
191 | return conf; |
192 | ||
193 | out: | |
194 | kfree(conf); | |
195 | return NULL; | |
196 | } | |
197 | ||
fd01b88c | 198 | static int linear_run (struct mddev *mddev) |
7c7546cc | 199 | { |
e849b938 | 200 | struct linear_conf *conf; |
7c7546cc | 201 | |
0894cc30 AN |
202 | if (md_check_no_bitmap(mddev)) |
203 | return -EINVAL; | |
7c7546cc N |
204 | conf = linear_conf(mddev, mddev->raid_disks); |
205 | ||
206 | if (!conf) | |
207 | return 1; | |
208 | mddev->private = conf; | |
1f403624 | 209 | md_set_array_sectors(mddev, linear_size(mddev, 0, 0)); |
7c7546cc | 210 | |
1da177e4 | 211 | blk_queue_merge_bvec(mddev->queue, linear_mergeable_bvec); |
26be34dc N |
212 | mddev->queue->backing_dev_info.congested_fn = linear_congested; |
213 | mddev->queue->backing_dev_info.congested_data = mddev; | |
a91a2785 | 214 | return md_integrity_register(mddev); |
7c7546cc | 215 | } |
1da177e4 | 216 | |
fd01b88c | 217 | static int linear_add(struct mddev *mddev, struct md_rdev *rdev) |
7c7546cc N |
218 | { |
219 | /* Adding a drive to a linear array allows the array to grow. | |
220 | * It is permitted if the new drive has a matching superblock | |
221 | * already on it, with raid_disk equal to raid_disks. | |
222 | * It is achieved by creating a new linear_private_data structure | |
223 | * and swapping it in in-place of the current one. | |
224 | * The current one is never freed until the array is stopped. | |
225 | * This avoids races. | |
226 | */ | |
e849b938 | 227 | struct linear_conf *newconf, *oldconf; |
7c7546cc | 228 | |
a778b73f | 229 | if (rdev->saved_raid_disk != mddev->raid_disks) |
7c7546cc N |
230 | return -EINVAL; |
231 | ||
a778b73f | 232 | rdev->raid_disk = rdev->saved_raid_disk; |
09cd9270 | 233 | rdev->saved_raid_disk = -1; |
a778b73f | 234 | |
7c7546cc N |
235 | newconf = linear_conf(mddev,mddev->raid_disks+1); |
236 | ||
237 | if (!newconf) | |
238 | return -ENOMEM; | |
239 | ||
495d3573 | 240 | oldconf = rcu_dereference(mddev->private); |
7c7546cc | 241 | mddev->raid_disks++; |
af11c397 | 242 | rcu_assign_pointer(mddev->private, newconf); |
1f403624 | 243 | md_set_array_sectors(mddev, linear_size(mddev, 0, 0)); |
f233ea5c | 244 | set_capacity(mddev->gendisk, mddev->array_sectors); |
449aad3e | 245 | revalidate_disk(mddev->gendisk); |
b119cbab | 246 | kfree_rcu(oldconf, rcu); |
7c7546cc | 247 | return 0; |
1da177e4 LT |
248 | } |
249 | ||
fd01b88c | 250 | static int linear_stop (struct mddev *mddev) |
1da177e4 | 251 | { |
e849b938 | 252 | struct linear_conf *conf = mddev->private; |
af11c397 S |
253 | |
254 | /* | |
255 | * We do not require rcu protection here since | |
256 | * we hold reconfig_mutex for both linear_add and | |
257 | * linear_stop, so they cannot race. | |
495d3573 N |
258 | * We should make sure any old 'conf's are properly |
259 | * freed though. | |
af11c397 | 260 | */ |
495d3573 | 261 | rcu_barrier(); |
1da177e4 | 262 | blk_sync_queue(mddev->queue); /* the unplug fn references 'conf'*/ |
495d3573 | 263 | kfree(conf); |
ef2f80ff | 264 | mddev->private = NULL; |
1da177e4 LT |
265 | |
266 | return 0; | |
267 | } | |
268 | ||
b4fdcb02 | 269 | static void linear_make_request(struct mddev *mddev, struct bio *bio) |
1da177e4 | 270 | { |
a7120771 | 271 | struct dev_info *tmp_dev; |
4db7cdc8 | 272 | sector_t start_sector; |
1da177e4 | 273 | |
e9c7469b TH |
274 | if (unlikely(bio->bi_rw & REQ_FLUSH)) { |
275 | md_flush_request(mddev, bio); | |
5a7bbad2 | 276 | return; |
e5dcdd80 N |
277 | } |
278 | ||
af11c397 | 279 | rcu_read_lock(); |
1da177e4 | 280 | tmp_dev = which_dev(mddev, bio->bi_sector); |
4db7cdc8 SS |
281 | start_sector = tmp_dev->end_sector - tmp_dev->rdev->sectors; |
282 | ||
af11c397 | 283 | |
4db7cdc8 SS |
284 | if (unlikely(bio->bi_sector >= (tmp_dev->end_sector) |
285 | || (bio->bi_sector < start_sector))) { | |
1da177e4 LT |
286 | char b[BDEVNAME_SIZE]; |
287 | ||
2dc40f80 N |
288 | printk(KERN_ERR |
289 | "md/linear:%s: make_request: Sector %llu out of bounds on " | |
290 | "dev %s: %llu sectors, offset %llu\n", | |
291 | mdname(mddev), | |
292 | (unsigned long long)bio->bi_sector, | |
293 | bdevname(tmp_dev->rdev->bdev, b), | |
294 | (unsigned long long)tmp_dev->rdev->sectors, | |
295 | (unsigned long long)start_sector); | |
af11c397 | 296 | rcu_read_unlock(); |
6712ecf8 | 297 | bio_io_error(bio); |
5a7bbad2 | 298 | return; |
1da177e4 LT |
299 | } |
300 | if (unlikely(bio->bi_sector + (bio->bi_size >> 9) > | |
4db7cdc8 | 301 | tmp_dev->end_sector)) { |
1da177e4 LT |
302 | /* This bio crosses a device boundary, so we have to |
303 | * split it. | |
304 | */ | |
305 | struct bio_pair *bp; | |
af11c397 S |
306 | sector_t end_sector = tmp_dev->end_sector; |
307 | ||
308 | rcu_read_unlock(); | |
6283815d | 309 | |
af11c397 | 310 | bp = bio_split(bio, end_sector - bio->bi_sector); |
6283815d | 311 | |
5a7bbad2 CH |
312 | linear_make_request(mddev, &bp->bio1); |
313 | linear_make_request(mddev, &bp->bio2); | |
1da177e4 | 314 | bio_pair_release(bp); |
5a7bbad2 | 315 | return; |
1da177e4 LT |
316 | } |
317 | ||
318 | bio->bi_bdev = tmp_dev->rdev->bdev; | |
4db7cdc8 | 319 | bio->bi_sector = bio->bi_sector - start_sector |
6283815d | 320 | + tmp_dev->rdev->data_offset; |
af11c397 | 321 | rcu_read_unlock(); |
5a7bbad2 | 322 | generic_make_request(bio); |
1da177e4 LT |
323 | } |
324 | ||
fd01b88c | 325 | static void linear_status (struct seq_file *seq, struct mddev *mddev) |
1da177e4 LT |
326 | { |
327 | ||
9d8f0363 | 328 | seq_printf(seq, " %dk rounding", mddev->chunk_sectors / 2); |
1da177e4 LT |
329 | } |
330 | ||
331 | ||
84fc4b56 | 332 | static struct md_personality linear_personality = |
1da177e4 LT |
333 | { |
334 | .name = "linear", | |
2604b703 | 335 | .level = LEVEL_LINEAR, |
1da177e4 LT |
336 | .owner = THIS_MODULE, |
337 | .make_request = linear_make_request, | |
338 | .run = linear_run, | |
339 | .stop = linear_stop, | |
340 | .status = linear_status, | |
7c7546cc | 341 | .hot_add_disk = linear_add, |
80c3a6ce | 342 | .size = linear_size, |
1da177e4 LT |
343 | }; |
344 | ||
345 | static int __init linear_init (void) | |
346 | { | |
2604b703 | 347 | return register_md_personality (&linear_personality); |
1da177e4 LT |
348 | } |
349 | ||
350 | static void linear_exit (void) | |
351 | { | |
2604b703 | 352 | unregister_md_personality (&linear_personality); |
1da177e4 LT |
353 | } |
354 | ||
355 | ||
356 | module_init(linear_init); | |
357 | module_exit(linear_exit); | |
358 | MODULE_LICENSE("GPL"); | |
0efb9e61 | 359 | MODULE_DESCRIPTION("Linear device concatenation personality for MD"); |
d9d166c2 N |
360 | MODULE_ALIAS("md-personality-1"); /* LINEAR - deprecated*/ |
361 | MODULE_ALIAS("md-linear"); | |
2604b703 | 362 | MODULE_ALIAS("md-level--1"); |