1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Copyright (C) 2001-2003 Sistina Software (UK) Limited.
4 *
5 * This file is released under the GPL.
6 */
7
8#include "dm.h"
9#include <linux/device-mapper.h>
10
11#include <linux/module.h>
12#include <linux/init.h>
13#include <linux/blkdev.h>
14#include <linux/bio.h>
15#include <linux/dax.h>
16#include <linux/slab.h>
17#include <linux/log2.h>
18
19static struct workqueue_struct *dm_stripe_wq;
20
21#define DM_MSG_PREFIX "striped"
22#define DM_IO_ERROR_THRESHOLD 15
23
24struct stripe {
25 struct dm_dev *dev;
26 sector_t physical_start;
27
28 atomic_t error_count;
29};
30
31struct stripe_c {
32 uint32_t stripes;
33 int stripes_shift;
34
35 /* The size of this target / num. stripes */
36 sector_t stripe_width;
37
38 uint32_t chunk_size;
39 int chunk_size_shift;
40
41 /* Needed for handling events */
42 struct dm_target *ti;
43
44 /* Work struct used for triggering events*/
45 struct work_struct trigger_event;
46
47 struct stripe stripe[] __counted_by(stripes);
48};
49
50/*
51 * An event is triggered whenever a drive
52 * drops out of a stripe volume.
53 */
54static void trigger_event(struct work_struct *work)
55{
56 struct stripe_c *sc = container_of(work, struct stripe_c,
57 trigger_event);
58 dm_table_event(t: sc->ti->table);
59}
60
61/*
62 * Parse a single <dev> <sector> pair
63 */
64static int get_stripe(struct dm_target *ti, struct stripe_c *sc,
65 unsigned int stripe, char **argv)
66{
67 unsigned long long start;
68 char dummy;
69 int ret;
70
71 if (sscanf(argv[1], "%llu%c", &start, &dummy) != 1)
72 return -EINVAL;
73
74 ret = dm_get_device(ti, path: argv[0], mode: dm_table_get_mode(t: ti->table),
75 result: &sc->stripe[stripe].dev);
76 if (ret)
77 return ret;
78
79 sc->stripe[stripe].physical_start = start;
80
81 return 0;
82}
83
84/*
85 * Construct a striped mapping.
86 * <number of stripes> <chunk size> [<dev_path> <offset>]+
87 */
88static int stripe_ctr(struct dm_target *ti, unsigned int argc, char **argv)
89{
90 struct stripe_c *sc;
91 sector_t width, tmp_len;
92 uint32_t stripes;
93 uint32_t chunk_size;
94 int r;
95 unsigned int i;
96
97 if (argc < 2) {
98 ti->error = "Not enough arguments";
99 return -EINVAL;
100 }
101
102 if (kstrtouint(s: argv[0], base: 10, res: &stripes) || !stripes) {
103 ti->error = "Invalid stripe count";
104 return -EINVAL;
105 }
106
107 if (kstrtouint(s: argv[1], base: 10, res: &chunk_size) || !chunk_size) {
108 ti->error = "Invalid chunk_size";
109 return -EINVAL;
110 }
111
112 width = ti->len;
113 if (sector_div(width, stripes)) {
114 ti->error = "Target length not divisible by number of stripes";
115 return -EINVAL;
116 }
117
118 tmp_len = width;
119 if (sector_div(tmp_len, chunk_size)) {
120 ti->error = "Target length not divisible by chunk size";
121 return -EINVAL;
122 }
123
124 /*
125 * Do we have enough arguments for that many stripes ?
126 */
127 if (argc != (2 + 2 * stripes)) {
128 ti->error = "Not enough destinations specified";
129 return -EINVAL;
130 }
131
132 sc = kmalloc(struct_size(sc, stripe, stripes), GFP_KERNEL);
133 if (!sc) {
134 ti->error = "Memory allocation for striped context failed";
135 return -ENOMEM;
136 }
137
138 INIT_WORK(&sc->trigger_event, trigger_event);
139
140 /* Set pointer to dm target; used in trigger_event */
141 sc->ti = ti;
142 sc->stripes = stripes;
143 sc->stripe_width = width;
144
145 if (stripes & (stripes - 1))
146 sc->stripes_shift = -1;
147 else
148 sc->stripes_shift = __ffs(stripes);
149
150 r = dm_set_target_max_io_len(ti, len: chunk_size);
151 if (r) {
152 kfree(objp: sc);
153 return r;
154 }
155
156 ti->num_flush_bios = stripes;
157 ti->num_discard_bios = stripes;
158 ti->num_secure_erase_bios = stripes;
159 ti->num_write_zeroes_bios = stripes;
160 ti->flush_bypasses_map = true;
161
162 sc->chunk_size = chunk_size;
163 if (chunk_size & (chunk_size - 1))
164 sc->chunk_size_shift = -1;
165 else
166 sc->chunk_size_shift = __ffs(chunk_size);
167
168 /*
169 * Get the stripe destinations.
170 */
171 for (i = 0; i < stripes; i++) {
172 argv += 2;
173
174 r = get_stripe(ti, sc, stripe: i, argv);
175 if (r < 0) {
176 ti->error = "Couldn't parse stripe destination";
177 while (i--)
178 dm_put_device(ti, d: sc->stripe[i].dev);
179 kfree(objp: sc);
180 return r;
181 }
182 atomic_set(v: &(sc->stripe[i].error_count), i: 0);
183 }
184
185 ti->private = sc;
186
187 return 0;
188}
189
190static void stripe_dtr(struct dm_target *ti)
191{
192 unsigned int i;
193 struct stripe_c *sc = ti->private;
194
195 for (i = 0; i < sc->stripes; i++)
196 dm_put_device(ti, d: sc->stripe[i].dev);
197
198 flush_work(work: &sc->trigger_event);
199 kfree(objp: sc);
200}
201
202static void stripe_map_sector(struct stripe_c *sc, sector_t sector,
203 uint32_t *stripe, sector_t *result)
204{
205 sector_t chunk = dm_target_offset(sc->ti, sector);
206 sector_t chunk_offset;
207
208 if (sc->chunk_size_shift < 0)
209 chunk_offset = sector_div(chunk, sc->chunk_size);
210 else {
211 chunk_offset = chunk & (sc->chunk_size - 1);
212 chunk >>= sc->chunk_size_shift;
213 }
214
215 if (sc->stripes_shift < 0)
216 *stripe = sector_div(chunk, sc->stripes);
217 else {
218 *stripe = chunk & (sc->stripes - 1);
219 chunk >>= sc->stripes_shift;
220 }
221
222 if (sc->chunk_size_shift < 0)
223 chunk *= sc->chunk_size;
224 else
225 chunk <<= sc->chunk_size_shift;
226
227 *result = chunk + chunk_offset;
228}
229
230static void stripe_map_range_sector(struct stripe_c *sc, sector_t sector,
231 uint32_t target_stripe, sector_t *result)
232{
233 uint32_t stripe;
234
235 stripe_map_sector(sc, sector, stripe: &stripe, result);
236 if (stripe == target_stripe)
237 return;
238
239 /* round down */
240 sector = *result;
241 if (sc->chunk_size_shift < 0)
242 *result -= sector_div(sector, sc->chunk_size);
243 else
244 *result = sector & ~(sector_t)(sc->chunk_size - 1);
245
246 if (target_stripe < stripe)
247 *result += sc->chunk_size; /* next chunk */
248}
249
250static int stripe_map_range(struct stripe_c *sc, struct bio *bio,
251 uint32_t target_stripe)
252{
253 sector_t begin, end;
254
255 stripe_map_range_sector(sc, sector: bio->bi_iter.bi_sector,
256 target_stripe, result: &begin);
257 stripe_map_range_sector(sc, bio_end_sector(bio),
258 target_stripe, result: &end);
259 if (begin < end) {
260 bio_set_dev(bio, bdev: sc->stripe[target_stripe].dev->bdev);
261 bio->bi_iter.bi_sector = begin +
262 sc->stripe[target_stripe].physical_start;
263 bio->bi_iter.bi_size = to_bytes(n: end - begin);
264 return DM_MAPIO_REMAPPED;
265 }
266
267 /* The range doesn't map to the target stripe */
268 bio_endio(bio);
269 return DM_MAPIO_SUBMITTED;
270}
271
272int stripe_map(struct dm_target *ti, struct bio *bio)
273{
274 struct stripe_c *sc = ti->private;
275 uint32_t stripe;
276 unsigned int target_bio_nr;
277
278 if (bio->bi_opf & REQ_PREFLUSH) {
279 target_bio_nr = dm_bio_get_target_bio_nr(bio);
280 BUG_ON(target_bio_nr >= sc->stripes);
281 bio_set_dev(bio, bdev: sc->stripe[target_bio_nr].dev->bdev);
282 return DM_MAPIO_REMAPPED;
283 }
284 if (unlikely(bio_op(bio) == REQ_OP_DISCARD) ||
285 unlikely(bio_op(bio) == REQ_OP_SECURE_ERASE) ||
286 unlikely(bio_op(bio) == REQ_OP_WRITE_ZEROES)) {
287 target_bio_nr = dm_bio_get_target_bio_nr(bio);
288 BUG_ON(target_bio_nr >= sc->stripes);
289 return stripe_map_range(sc, bio, target_stripe: target_bio_nr);
290 }
291
292 stripe_map_sector(sc, sector: bio->bi_iter.bi_sector,
293 stripe: &stripe, result: &bio->bi_iter.bi_sector);
294
295 bio->bi_iter.bi_sector += sc->stripe[stripe].physical_start;
296 bio_set_dev(bio, bdev: sc->stripe[stripe].dev->bdev);
297
298 return DM_MAPIO_REMAPPED;
299}
300
301#if IS_ENABLED(CONFIG_FS_DAX)
302static struct dax_device *stripe_dax_pgoff(struct dm_target *ti, pgoff_t *pgoff)
303{
304 struct stripe_c *sc = ti->private;
305 struct block_device *bdev;
306 sector_t dev_sector;
307 uint32_t stripe;
308
309 stripe_map_sector(sc, *pgoff * PAGE_SECTORS, &stripe, &dev_sector);
310 dev_sector += sc->stripe[stripe].physical_start;
311 bdev = sc->stripe[stripe].dev->bdev;
312
313 *pgoff = (get_start_sect(bdev) + dev_sector) >> PAGE_SECTORS_SHIFT;
314 return sc->stripe[stripe].dev->dax_dev;
315}
316
317static long stripe_dax_direct_access(struct dm_target *ti, pgoff_t pgoff,
318 long nr_pages, enum dax_access_mode mode, void **kaddr,
319 unsigned long *pfn)
320{
321 struct dax_device *dax_dev = stripe_dax_pgoff(ti, &pgoff);
322
323 return dax_direct_access(dax_dev, pgoff, nr_pages, mode, kaddr, pfn);
324}
325
326static int stripe_dax_zero_page_range(struct dm_target *ti, pgoff_t pgoff,
327 size_t nr_pages)
328{
329 struct dax_device *dax_dev = stripe_dax_pgoff(ti, &pgoff);
330
331 return dax_zero_page_range(dax_dev, pgoff, nr_pages);
332}
333
334static size_t stripe_dax_recovery_write(struct dm_target *ti, pgoff_t pgoff,
335 void *addr, size_t bytes, struct iov_iter *i)
336{
337 struct dax_device *dax_dev = stripe_dax_pgoff(ti, &pgoff);
338
339 return dax_recovery_write(dax_dev, pgoff, addr, bytes, i);
340}
341
342#else
343#define stripe_dax_direct_access NULL
344#define stripe_dax_zero_page_range NULL
345#define stripe_dax_recovery_write NULL
346#endif
347
348/*
349 * Stripe status:
350 *
351 * INFO
352 * #stripes [stripe_name <stripe_name>] [group word count]
353 * [error count 'A|D' <error count 'A|D'>]
354 *
355 * TABLE
356 * #stripes [stripe chunk size]
357 * [stripe_name physical_start <stripe_name physical_start>]
358 *
359 */
360
361static void stripe_status(struct dm_target *ti, status_type_t type,
362 unsigned int status_flags, char *result, unsigned int maxlen)
363{
364 struct stripe_c *sc = ti->private;
365 unsigned int sz = 0;
366 unsigned int i;
367
368 switch (type) {
369 case STATUSTYPE_INFO:
370 DMEMIT("%d ", sc->stripes);
371 for (i = 0; i < sc->stripes; i++)
372 DMEMIT("%s ", sc->stripe[i].dev->name);
373
374 DMEMIT("1 ");
375 for (i = 0; i < sc->stripes; i++)
376 DMEMIT("%c", atomic_read(&(sc->stripe[i].error_count)) ? 'D' : 'A');
377 break;
378
379 case STATUSTYPE_TABLE:
380 DMEMIT("%d %llu", sc->stripes,
381 (unsigned long long)sc->chunk_size);
382 for (i = 0; i < sc->stripes; i++)
383 DMEMIT(" %s %llu", sc->stripe[i].dev->name,
384 (unsigned long long)sc->stripe[i].physical_start);
385 break;
386
387 case STATUSTYPE_IMA:
388 DMEMIT_TARGET_NAME_VERSION(ti->type);
389 DMEMIT(",stripes=%d,chunk_size=%llu", sc->stripes,
390 (unsigned long long)sc->chunk_size);
391
392 for (i = 0; i < sc->stripes; i++) {
393 DMEMIT(",stripe_%d_device_name=%s", i, sc->stripe[i].dev->name);
394 DMEMIT(",stripe_%d_physical_start=%llu", i,
395 (unsigned long long)sc->stripe[i].physical_start);
396 DMEMIT(",stripe_%d_status=%c", i,
397 atomic_read(&(sc->stripe[i].error_count)) ? 'D' : 'A');
398 }
399 DMEMIT(";");
400 break;
401 }
402}
403
404static int stripe_end_io(struct dm_target *ti, struct bio *bio,
405 blk_status_t *error)
406{
407 unsigned int i;
408 char major_minor[22];
409 struct stripe_c *sc = ti->private;
410
411 if (!*error)
412 return DM_ENDIO_DONE; /* I/O complete */
413
414 if (bio->bi_opf & REQ_RAHEAD)
415 return DM_ENDIO_DONE;
416
417 if (*error == BLK_STS_NOTSUPP)
418 return DM_ENDIO_DONE;
419
420 format_dev_t(major_minor, bio_dev(bio));
421
422 /*
423 * Test to see which stripe drive triggered the event
424 * and increment error count for all stripes on that device.
425 * If the error count for a given device exceeds the threshold
426 * value we will no longer trigger any further events.
427 */
428 for (i = 0; i < sc->stripes; i++)
429 if (!strcmp(sc->stripe[i].dev->name, major_minor)) {
430 atomic_inc(v: &(sc->stripe[i].error_count));
431 if (atomic_read(v: &(sc->stripe[i].error_count)) <
432 DM_IO_ERROR_THRESHOLD)
433 queue_work(wq: dm_stripe_wq, work: &sc->trigger_event);
434 }
435
436 return DM_ENDIO_DONE;
437}
438
439static int stripe_iterate_devices(struct dm_target *ti,
440 iterate_devices_callout_fn fn, void *data)
441{
442 struct stripe_c *sc = ti->private;
443 int ret = 0;
444 unsigned int i = 0;
445
446 do {
447 ret = fn(ti, sc->stripe[i].dev,
448 sc->stripe[i].physical_start,
449 sc->stripe_width, data);
450 } while (!ret && ++i < sc->stripes);
451
452 return ret;
453}
454
455static void stripe_io_hints(struct dm_target *ti,
456 struct queue_limits *limits)
457{
458 struct stripe_c *sc = ti->private;
459 unsigned int io_min, io_opt;
460
461 limits->chunk_sectors = sc->chunk_size;
462
463 if (!check_shl_overflow(sc->chunk_size, SECTOR_SHIFT, &io_min) &&
464 !check_mul_overflow(io_min, sc->stripes, &io_opt)) {
465 limits->io_min = io_min;
466 limits->io_opt = io_opt;
467 }
468}
469
470static struct target_type stripe_target = {
471 .name = "striped",
472 .version = {1, 7, 0},
473 .features = DM_TARGET_PASSES_INTEGRITY | DM_TARGET_NOWAIT |
474 DM_TARGET_ATOMIC_WRITES | DM_TARGET_PASSES_CRYPTO,
475 .module = THIS_MODULE,
476 .ctr = stripe_ctr,
477 .dtr = stripe_dtr,
478 .map = stripe_map,
479 .end_io = stripe_end_io,
480 .status = stripe_status,
481 .iterate_devices = stripe_iterate_devices,
482 .io_hints = stripe_io_hints,
483 .direct_access = stripe_dax_direct_access,
484 .dax_zero_page_range = stripe_dax_zero_page_range,
485 .dax_recovery_write = stripe_dax_recovery_write,
486};
487
488int __init dm_stripe_init(void)
489{
490 int r;
491
492 dm_stripe_wq = alloc_workqueue("dm_stripe_wq", 0, 0);
493 if (!dm_stripe_wq)
494 return -ENOMEM;
495 r = dm_register_target(t: &stripe_target);
496 if (r < 0) {
497 destroy_workqueue(wq: dm_stripe_wq);
498 DMWARN("target registration failed");
499 }
500
501 return r;
502}
503
504void dm_stripe_exit(void)
505{
506 dm_unregister_target(t: &stripe_target);
507 destroy_workqueue(wq: dm_stripe_wq);
508}
509