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