1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * linear.c : Multiple Devices driver for Linux Copyright (C) 1994-96 Marc 4 * ZYNGIER <zyngier@ufr-info-p7.ibp.fr> or <maz@gloups.fdn.fr> 5 */ 6 7 #include <linux/blkdev.h> 8 #include <linux/seq_file.h> 9 #include <linux/module.h> 10 #include <linux/slab.h> 11 #include <trace/events/block.h> 12 #include "md.h" 13 14 struct dev_info { 15 struct md_rdev *rdev; 16 sector_t end_sector; 17 }; 18 19 struct linear_conf { 20 struct rcu_head rcu; 21 sector_t array_sectors; 22 /* a copy of mddev->raid_disks */ 23 int raid_disks; 24 struct dev_info disks[] __counted_by(raid_disks); 25 }; 26 27 /* 28 * find which device holds a particular offset 29 */ 30 static inline struct dev_info *which_dev(struct mddev *mddev, sector_t sector) 31 { 32 int lo, mid, hi; 33 struct linear_conf *conf; 34 35 lo = 0; 36 hi = mddev->raid_disks - 1; 37 conf = mddev->private; 38 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; 53 } 54 55 static sector_t linear_size(struct mddev *mddev, sector_t sectors, int raid_disks) 56 { 57 struct linear_conf *conf; 58 sector_t array_sectors; 59 60 conf = mddev->private; 61 WARN_ONCE(sectors || raid_disks, 62 "%s does not support generic reshape\n", __func__); 63 array_sectors = conf->array_sectors; 64 65 return array_sectors; 66 } 67 68 static int linear_set_limits(struct mddev *mddev) 69 { 70 struct queue_limits lim; 71 int err; 72 73 md_init_stacking_limits(&lim); 74 lim.features |= BLK_FEAT_NOWAIT; 75 lim.max_hw_sectors = mddev->chunk_sectors; 76 lim.logical_block_size = mddev->logical_block_size; 77 lim.max_write_zeroes_sectors = mddev->chunk_sectors; 78 lim.max_hw_wzeroes_unmap_sectors = mddev->chunk_sectors; 79 lim.io_min = mddev->chunk_sectors << 9; 80 lim.features |= BLK_FEAT_ATOMIC_WRITES; 81 err = mddev_stack_rdev_limits(mddev, &lim, MDDEV_STACK_INTEGRITY); 82 if (err) 83 return err; 84 85 return queue_limits_set(mddev->gendisk->queue, &lim); 86 } 87 88 static struct linear_conf *linear_conf(struct mddev *mddev, int raid_disks) 89 { 90 struct linear_conf *conf; 91 struct md_rdev *rdev; 92 int ret = -EINVAL; 93 int cnt; 94 int i; 95 96 conf = kzalloc_flex(*conf, disks, raid_disks); 97 if (!conf) 98 return ERR_PTR(-ENOMEM); 99 100 /* 101 * conf->raid_disks is copy of mddev->raid_disks. The reason to 102 * keep a copy of mddev->raid_disks in struct linear_conf is, 103 * mddev->raid_disks may not be consistent with pointers number of 104 * conf->disks[] when it is updated in linear_add() and used to 105 * iterate old conf->disks[] earray in linear_congested(). 106 * Here conf->raid_disks is always consitent with number of 107 * pointers in conf->disks[] array, and mddev->private is updated 108 * with rcu_assign_pointer() in linear_addr(), such race can be 109 * avoided. 110 */ 111 conf->raid_disks = raid_disks; 112 113 cnt = 0; 114 conf->array_sectors = 0; 115 116 rdev_for_each(rdev, mddev) { 117 int j = rdev->raid_disk; 118 struct dev_info *disk = conf->disks + j; 119 sector_t sectors; 120 121 if (j < 0 || j >= raid_disks || disk->rdev) { 122 pr_warn("md/linear:%s: disk numbering problem. Aborting!\n", 123 mdname(mddev)); 124 goto out; 125 } 126 127 disk->rdev = rdev; 128 if (mddev->chunk_sectors) { 129 sectors = rdev->sectors; 130 sector_div(sectors, mddev->chunk_sectors); 131 rdev->sectors = sectors * mddev->chunk_sectors; 132 } 133 134 conf->array_sectors += rdev->sectors; 135 cnt++; 136 } 137 if (cnt != raid_disks) { 138 pr_warn("md/linear:%s: not enough drives present. Aborting!\n", 139 mdname(mddev)); 140 goto out; 141 } 142 143 /* 144 * Here we calculate the device offsets. 145 */ 146 conf->disks[0].end_sector = conf->disks[0].rdev->sectors; 147 148 for (i = 1; i < raid_disks; i++) 149 conf->disks[i].end_sector = 150 conf->disks[i-1].end_sector + 151 conf->disks[i].rdev->sectors; 152 153 if (!mddev_is_dm(mddev)) { 154 ret = linear_set_limits(mddev); 155 if (ret) 156 goto out; 157 } 158 159 return conf; 160 161 out: 162 kfree(conf); 163 return ERR_PTR(ret); 164 } 165 166 static int linear_run(struct mddev *mddev) 167 { 168 struct linear_conf *conf; 169 int ret; 170 171 if (md_check_no_bitmap(mddev)) 172 return -EINVAL; 173 174 conf = linear_conf(mddev, mddev->raid_disks); 175 if (IS_ERR(conf)) 176 return PTR_ERR(conf); 177 178 mddev->private = conf; 179 md_set_array_sectors(mddev, linear_size(mddev, 0, 0)); 180 181 ret = md_integrity_register(mddev); 182 if (ret) { 183 kfree(conf); 184 mddev->private = NULL; 185 } 186 return ret; 187 } 188 189 static int linear_add(struct mddev *mddev, struct md_rdev *rdev) 190 { 191 /* Adding a drive to a linear array allows the array to grow. 192 * It is permitted if the new drive has a matching superblock 193 * already on it, with raid_disk equal to raid_disks. 194 * It is achieved by creating a new linear_private_data structure 195 * and swapping it in in-place of the current one. 196 * The current one is never freed until the array is stopped. 197 * This avoids races. 198 */ 199 struct linear_conf *newconf, *oldconf; 200 201 if (rdev->saved_raid_disk != mddev->raid_disks) 202 return -EINVAL; 203 204 rdev->raid_disk = rdev->saved_raid_disk; 205 rdev->saved_raid_disk = -1; 206 207 newconf = linear_conf(mddev, mddev->raid_disks + 1); 208 if (IS_ERR(newconf)) 209 return PTR_ERR(newconf); 210 211 /* newconf->raid_disks already keeps a copy of * the increased 212 * value of mddev->raid_disks, WARN_ONCE() is just used to make 213 * sure of this. It is possible that oldconf is still referenced 214 * in linear_congested(), therefore kfree_rcu() is used to free 215 * oldconf until no one uses it anymore. 216 */ 217 oldconf = rcu_dereference_protected(mddev->private, 218 lockdep_is_held(&mddev->reconfig_mutex)); 219 mddev->raid_disks++; 220 WARN_ONCE(mddev->raid_disks != newconf->raid_disks, 221 "copied raid_disks doesn't match mddev->raid_disks"); 222 rcu_assign_pointer(mddev->private, newconf); 223 md_set_array_sectors(mddev, linear_size(mddev, 0, 0)); 224 set_capacity_and_notify(mddev->gendisk, mddev->array_sectors); 225 kfree_rcu(oldconf, rcu); 226 return 0; 227 } 228 229 static void linear_free(struct mddev *mddev, void *priv) 230 { 231 struct linear_conf *conf = priv; 232 233 kfree(conf); 234 } 235 236 static bool linear_make_request(struct mddev *mddev, struct bio *bio) 237 { 238 struct dev_info *tmp_dev; 239 sector_t start_sector, end_sector, data_offset; 240 sector_t bio_sector = bio->bi_iter.bi_sector; 241 242 if (unlikely(bio->bi_opf & REQ_PREFLUSH) 243 && md_flush_request(mddev, bio)) 244 return true; 245 246 tmp_dev = which_dev(mddev, bio_sector); 247 start_sector = tmp_dev->end_sector - tmp_dev->rdev->sectors; 248 end_sector = tmp_dev->end_sector; 249 data_offset = tmp_dev->rdev->data_offset; 250 251 if (unlikely(bio_sector >= end_sector || 252 bio_sector < start_sector)) 253 goto out_of_bounds; 254 255 if (unlikely(is_rdev_broken(tmp_dev->rdev))) { 256 md_error(mddev, tmp_dev->rdev); 257 bio_io_error(bio); 258 return true; 259 } 260 261 if (unlikely(bio_end_sector(bio) > end_sector)) { 262 /* This bio crosses a device boundary, so we have to split it */ 263 bio = bio_submit_split_bioset(bio, end_sector - bio_sector, 264 &mddev->bio_set); 265 if (!bio) 266 return true; 267 } 268 269 md_account_bio(mddev, &bio); 270 bio_set_dev(bio, tmp_dev->rdev->bdev); 271 bio->bi_iter.bi_sector = bio->bi_iter.bi_sector - 272 start_sector + data_offset; 273 274 if (unlikely((bio_op(bio) == REQ_OP_DISCARD) && 275 !bdev_max_discard_sectors(bio->bi_bdev))) { 276 /* Just ignore it */ 277 bio_endio(bio); 278 } else { 279 if (mddev->gendisk) 280 trace_block_bio_remap(bio, disk_devt(mddev->gendisk), 281 bio_sector); 282 mddev_check_write_zeroes(mddev, bio); 283 submit_bio_noacct(bio); 284 } 285 return true; 286 287 out_of_bounds: 288 pr_err("md/linear:%s: make_request: Sector %llu out of bounds on dev %pg: %llu sectors, offset %llu\n", 289 mdname(mddev), 290 (unsigned long long)bio->bi_iter.bi_sector, 291 tmp_dev->rdev->bdev, 292 (unsigned long long)tmp_dev->rdev->sectors, 293 (unsigned long long)start_sector); 294 bio_io_error(bio); 295 return true; 296 } 297 298 static void linear_status(struct seq_file *seq, struct mddev *mddev) 299 { 300 seq_printf(seq, " %dk rounding", mddev->chunk_sectors / 2); 301 } 302 303 static void linear_error(struct mddev *mddev, struct md_rdev *rdev) 304 { 305 if (!test_and_set_bit(MD_BROKEN, &mddev->flags)) { 306 char *md_name = mdname(mddev); 307 308 pr_crit("md/linear%s: Disk failure on %pg detected, failing array.\n", 309 md_name, rdev->bdev); 310 } 311 } 312 313 static void linear_quiesce(struct mddev *mddev, int state) 314 { 315 } 316 317 static struct md_personality linear_personality = { 318 .head = { 319 .type = MD_PERSONALITY, 320 .id = ID_LINEAR, 321 .name = "linear", 322 .owner = THIS_MODULE, 323 }, 324 325 .make_request = linear_make_request, 326 .run = linear_run, 327 .free = linear_free, 328 .status = linear_status, 329 .hot_add_disk = linear_add, 330 .size = linear_size, 331 .quiesce = linear_quiesce, 332 .error_handler = linear_error, 333 }; 334 335 static int __init linear_init(void) 336 { 337 return register_md_submodule(&linear_personality.head); 338 } 339 340 static void linear_exit(void) 341 { 342 unregister_md_submodule(&linear_personality.head); 343 } 344 345 module_init(linear_init); 346 module_exit(linear_exit); 347 MODULE_LICENSE("GPL"); 348 MODULE_DESCRIPTION("Linear device concatenation personality for MD (deprecated)"); 349 MODULE_ALIAS("md-personality-1"); /* LINEAR - deprecated*/ 350 MODULE_ALIAS("md-linear"); 351 MODULE_ALIAS("md-level--1"); 352