dm-raid1.c 36 KB

12345678910111213141516171819202122232425262728293031323334353637383940414243444546474849505152535455565758596061626364656667686970717273747576777879808182838485868788899091929394959697989910010110210310410510610710810911011111211311411511611711811912012112212312412512612712812913013113213313413513613713813914014114214314414514614714814915015115215315415515615715815916016116216316416516616716816917017117217317417517617717817918018118218318418518618718818919019119219319419519619719819920020120220320420520620720820921021121221321421521621721821922022122222322422522622722822923023123223323423523623723823924024124224324424524624724824925025125225325425525625725825926026126226326426526626726826927027127227327427527627727827928028128228328428528628728828929029129229329429529629729829930030130230330430530630730830931031131231331431531631731831932032132232332432532632732832933033133233333433533633733833934034134234334434534634734834935035135235335435535635735835936036136236336436536636736836937037137237337437537637737837938038138238338438538638738838939039139239339439539639739839940040140240340440540640740840941041141241341441541641741841942042142242342442542642742842943043143243343443543643743843944044144244344444544644744844945045145245345445545645745845946046146246346446546646746846947047147247347447547647747847948048148248348448548648748848949049149249349449549649749849950050150250350450550650750850951051151251351451551651751851952052152252352452552652752852953053153253353453553653753853954054154254354454554654754854955055155255355455555655755855956056156256356456556656756856957057157257357457557657757857958058158258358458558658758858959059159259359459559659759859960060160260360460560660760860961061161261361461561661761861962062162262362462562662762862963063163263363463563663763863964064164264364464564664764864965065165265365465565665765865966066166266366466566666766866967067167267367467567667767867968068168268368468568668768868969069169269369469569669769869970070170270370470570670770870971071171271371471571671771871972072172272372472572672772872973073173273373473573673773873974074174274374474574674774874975075175275375475575675775875976076176276376476576676776876977077177277377477577677777877978078178278378478578678778878979079179279379479579679779879980080180280380480580680780880981081181281381481581681781881982082182282382482582682782882983083183283383483583683783883984084184284384484584684784884985085185285385485585685785885986086186286386486586686786886987087187287387487587687787887988088188288388488588688788888989089189289389489589689789889990090190290390490590690790890991091191291391491591691791891992092192292392492592692792892993093193293393493593693793893994094194294394494594694794894995095195295395495595695795895996096196296396496596696796896997097197297397497597697797897998098198298398498598698798898999099199299399499599699799899910001001100210031004100510061007100810091010101110121013101410151016101710181019102010211022102310241025102610271028102910301031103210331034103510361037103810391040104110421043104410451046104710481049105010511052105310541055105610571058105910601061106210631064106510661067106810691070107110721073107410751076107710781079108010811082108310841085108610871088108910901091109210931094109510961097109810991100110111021103110411051106110711081109111011111112111311141115111611171118111911201121112211231124112511261127112811291130113111321133113411351136113711381139114011411142114311441145114611471148114911501151115211531154115511561157115811591160116111621163116411651166116711681169117011711172117311741175117611771178117911801181118211831184118511861187118811891190119111921193119411951196119711981199120012011202120312041205120612071208120912101211121212131214121512161217121812191220122112221223122412251226122712281229123012311232123312341235123612371238123912401241124212431244124512461247124812491250125112521253125412551256125712581259126012611262126312641265126612671268126912701271127212731274127512761277127812791280128112821283128412851286128712881289129012911292129312941295129612971298129913001301130213031304130513061307130813091310131113121313131413151316131713181319132013211322132313241325132613271328132913301331133213331334133513361337133813391340134113421343134413451346134713481349135013511352135313541355135613571358135913601361136213631364136513661367136813691370137113721373137413751376137713781379138013811382138313841385138613871388138913901391139213931394139513961397139813991400140114021403140414051406140714081409141014111412141314141415141614171418141914201421142214231424142514261427142814291430143114321433143414351436143714381439144014411442144314441445144614471448144914501451145214531454145514561457145814591460146114621463146414651466146714681469147014711472147314741475147614771478147914801481148214831484148514861487148814891490149114921493149414951496149714981499150015011502150315041505150615071508150915101511
  1. /*
  2. * Copyright (C) 2003 Sistina Software Limited.
  3. * Copyright (C) 2005-2008 Red Hat, Inc. All rights reserved.
  4. *
  5. * This file is released under the GPL.
  6. */
  7. #include "dm-bio-record.h"
  8. #include <linux/init.h>
  9. #include <linux/mempool.h>
  10. #include <linux/module.h>
  11. #include <linux/pagemap.h>
  12. #include <linux/slab.h>
  13. #include <linux/workqueue.h>
  14. #include <linux/device-mapper.h>
  15. #include <linux/dm-io.h>
  16. #include <linux/dm-dirty-log.h>
  17. #include <linux/dm-kcopyd.h>
  18. #include <linux/dm-region-hash.h>
  19. #define DM_MSG_PREFIX "raid1"
  20. #define MAX_RECOVERY 1 /* Maximum number of regions recovered in parallel. */
  21. #define MAX_NR_MIRRORS (DM_KCOPYD_MAX_REGIONS + 1)
  22. #define DM_RAID1_HANDLE_ERRORS 0x01
  23. #define DM_RAID1_KEEP_LOG 0x02
  24. #define errors_handled(p) ((p)->features & DM_RAID1_HANDLE_ERRORS)
  25. #define keep_log(p) ((p)->features & DM_RAID1_KEEP_LOG)
  26. static DECLARE_WAIT_QUEUE_HEAD(_kmirrord_recovery_stopped);
  27. /*-----------------------------------------------------------------
  28. * Mirror set structures.
  29. *---------------------------------------------------------------*/
  30. enum dm_raid1_error {
  31. DM_RAID1_WRITE_ERROR,
  32. DM_RAID1_FLUSH_ERROR,
  33. DM_RAID1_SYNC_ERROR,
  34. DM_RAID1_READ_ERROR
  35. };
  36. struct mirror {
  37. struct mirror_set *ms;
  38. atomic_t error_count;
  39. unsigned long error_type;
  40. struct dm_dev *dev;
  41. sector_t offset;
  42. };
  43. struct mirror_set {
  44. struct dm_target *ti;
  45. struct list_head list;
  46. uint64_t features;
  47. spinlock_t lock; /* protects the lists */
  48. struct bio_list reads;
  49. struct bio_list writes;
  50. struct bio_list failures;
  51. struct bio_list holds; /* bios are waiting until suspend */
  52. struct dm_region_hash *rh;
  53. struct dm_kcopyd_client *kcopyd_client;
  54. struct dm_io_client *io_client;
  55. /* recovery */
  56. region_t nr_regions;
  57. int in_sync;
  58. int log_failure;
  59. int leg_failure;
  60. atomic_t suspend;
  61. atomic_t default_mirror; /* Default mirror */
  62. struct workqueue_struct *kmirrord_wq;
  63. struct work_struct kmirrord_work;
  64. struct timer_list timer;
  65. unsigned long timer_pending;
  66. struct work_struct trigger_event;
  67. unsigned int nr_mirrors;
  68. struct mirror mirror[];
  69. };
  70. DECLARE_DM_KCOPYD_THROTTLE_WITH_MODULE_PARM(raid1_resync_throttle,
  71. "A percentage of time allocated for raid resynchronization");
  72. static void wakeup_mirrord(void *context)
  73. {
  74. struct mirror_set *ms = context;
  75. queue_work(ms->kmirrord_wq, &ms->kmirrord_work);
  76. }
  77. static void delayed_wake_fn(struct timer_list *t)
  78. {
  79. struct mirror_set *ms = from_timer(ms, t, timer);
  80. clear_bit(0, &ms->timer_pending);
  81. wakeup_mirrord(ms);
  82. }
  83. static void delayed_wake(struct mirror_set *ms)
  84. {
  85. if (test_and_set_bit(0, &ms->timer_pending))
  86. return;
  87. ms->timer.expires = jiffies + HZ / 5;
  88. add_timer(&ms->timer);
  89. }
  90. static void wakeup_all_recovery_waiters(void *context)
  91. {
  92. wake_up_all(&_kmirrord_recovery_stopped);
  93. }
  94. static void queue_bio(struct mirror_set *ms, struct bio *bio, int rw)
  95. {
  96. unsigned long flags;
  97. int should_wake = 0;
  98. struct bio_list *bl;
  99. bl = (rw == WRITE) ? &ms->writes : &ms->reads;
  100. spin_lock_irqsave(&ms->lock, flags);
  101. should_wake = !(bl->head);
  102. bio_list_add(bl, bio);
  103. spin_unlock_irqrestore(&ms->lock, flags);
  104. if (should_wake)
  105. wakeup_mirrord(ms);
  106. }
  107. static void dispatch_bios(void *context, struct bio_list *bio_list)
  108. {
  109. struct mirror_set *ms = context;
  110. struct bio *bio;
  111. while ((bio = bio_list_pop(bio_list)))
  112. queue_bio(ms, bio, WRITE);
  113. }
  114. struct dm_raid1_bio_record {
  115. struct mirror *m;
  116. /* if details->bi_bdev == NULL, details were not saved */
  117. struct dm_bio_details details;
  118. region_t write_region;
  119. };
  120. /*
  121. * Every mirror should look like this one.
  122. */
  123. #define DEFAULT_MIRROR 0
  124. /*
  125. * This is yucky. We squirrel the mirror struct away inside
  126. * bi_next for read/write buffers. This is safe since the bh
  127. * doesn't get submitted to the lower levels of block layer.
  128. */
  129. static struct mirror *bio_get_m(struct bio *bio)
  130. {
  131. return (struct mirror *) bio->bi_next;
  132. }
  133. static void bio_set_m(struct bio *bio, struct mirror *m)
  134. {
  135. bio->bi_next = (struct bio *) m;
  136. }
  137. static struct mirror *get_default_mirror(struct mirror_set *ms)
  138. {
  139. return &ms->mirror[atomic_read(&ms->default_mirror)];
  140. }
  141. static void set_default_mirror(struct mirror *m)
  142. {
  143. struct mirror_set *ms = m->ms;
  144. struct mirror *m0 = &(ms->mirror[0]);
  145. atomic_set(&ms->default_mirror, m - m0);
  146. }
  147. static struct mirror *get_valid_mirror(struct mirror_set *ms)
  148. {
  149. struct mirror *m;
  150. for (m = ms->mirror; m < ms->mirror + ms->nr_mirrors; m++)
  151. if (!atomic_read(&m->error_count))
  152. return m;
  153. return NULL;
  154. }
  155. /* fail_mirror
  156. * @m: mirror device to fail
  157. * @error_type: one of the enum's, DM_RAID1_*_ERROR
  158. *
  159. * If errors are being handled, record the type of
  160. * error encountered for this device. If this type
  161. * of error has already been recorded, we can return;
  162. * otherwise, we must signal userspace by triggering
  163. * an event. Additionally, if the device is the
  164. * primary device, we must choose a new primary, but
  165. * only if the mirror is in-sync.
  166. *
  167. * This function must not block.
  168. */
  169. static void fail_mirror(struct mirror *m, enum dm_raid1_error error_type)
  170. {
  171. struct mirror_set *ms = m->ms;
  172. struct mirror *new;
  173. ms->leg_failure = 1;
  174. /*
  175. * error_count is used for nothing more than a
  176. * simple way to tell if a device has encountered
  177. * errors.
  178. */
  179. atomic_inc(&m->error_count);
  180. if (test_and_set_bit(error_type, &m->error_type))
  181. return;
  182. if (!errors_handled(ms))
  183. return;
  184. if (m != get_default_mirror(ms))
  185. goto out;
  186. if (!ms->in_sync && !keep_log(ms)) {
  187. /*
  188. * Better to issue requests to same failing device
  189. * than to risk returning corrupt data.
  190. */
  191. DMERR("Primary mirror (%s) failed while out-of-sync: Reads may fail.",
  192. m->dev->name);
  193. goto out;
  194. }
  195. new = get_valid_mirror(ms);
  196. if (new)
  197. set_default_mirror(new);
  198. else
  199. DMWARN("All sides of mirror have failed.");
  200. out:
  201. schedule_work(&ms->trigger_event);
  202. }
  203. static int mirror_flush(struct dm_target *ti)
  204. {
  205. struct mirror_set *ms = ti->private;
  206. unsigned long error_bits;
  207. unsigned int i;
  208. struct dm_io_region io[MAX_NR_MIRRORS];
  209. struct mirror *m;
  210. struct dm_io_request io_req = {
  211. .bi_opf = REQ_OP_WRITE | REQ_PREFLUSH | REQ_SYNC,
  212. .mem.type = DM_IO_KMEM,
  213. .mem.ptr.addr = NULL,
  214. .client = ms->io_client,
  215. };
  216. for (i = 0, m = ms->mirror; i < ms->nr_mirrors; i++, m++) {
  217. io[i].bdev = m->dev->bdev;
  218. io[i].sector = 0;
  219. io[i].count = 0;
  220. }
  221. error_bits = -1;
  222. dm_io(&io_req, ms->nr_mirrors, io, &error_bits);
  223. if (unlikely(error_bits != 0)) {
  224. for (i = 0; i < ms->nr_mirrors; i++)
  225. if (test_bit(i, &error_bits))
  226. fail_mirror(ms->mirror + i,
  227. DM_RAID1_FLUSH_ERROR);
  228. return -EIO;
  229. }
  230. return 0;
  231. }
  232. /*-----------------------------------------------------------------
  233. * Recovery.
  234. *
  235. * When a mirror is first activated we may find that some regions
  236. * are in the no-sync state. We have to recover these by
  237. * recopying from the default mirror to all the others.
  238. *---------------------------------------------------------------*/
  239. static void recovery_complete(int read_err, unsigned long write_err,
  240. void *context)
  241. {
  242. struct dm_region *reg = context;
  243. struct mirror_set *ms = dm_rh_region_context(reg);
  244. int m, bit = 0;
  245. if (read_err) {
  246. /* Read error means the failure of default mirror. */
  247. DMERR_LIMIT("Unable to read primary mirror during recovery");
  248. fail_mirror(get_default_mirror(ms), DM_RAID1_SYNC_ERROR);
  249. }
  250. if (write_err) {
  251. DMERR_LIMIT("Write error during recovery (error = 0x%lx)",
  252. write_err);
  253. /*
  254. * Bits correspond to devices (excluding default mirror).
  255. * The default mirror cannot change during recovery.
  256. */
  257. for (m = 0; m < ms->nr_mirrors; m++) {
  258. if (&ms->mirror[m] == get_default_mirror(ms))
  259. continue;
  260. if (test_bit(bit, &write_err))
  261. fail_mirror(ms->mirror + m,
  262. DM_RAID1_SYNC_ERROR);
  263. bit++;
  264. }
  265. }
  266. dm_rh_recovery_end(reg, !(read_err || write_err));
  267. }
  268. static void recover(struct mirror_set *ms, struct dm_region *reg)
  269. {
  270. unsigned int i;
  271. struct dm_io_region from, to[DM_KCOPYD_MAX_REGIONS], *dest;
  272. struct mirror *m;
  273. unsigned long flags = 0;
  274. region_t key = dm_rh_get_region_key(reg);
  275. sector_t region_size = dm_rh_get_region_size(ms->rh);
  276. /* fill in the source */
  277. m = get_default_mirror(ms);
  278. from.bdev = m->dev->bdev;
  279. from.sector = m->offset + dm_rh_region_to_sector(ms->rh, key);
  280. if (key == (ms->nr_regions - 1)) {
  281. /*
  282. * The final region may be smaller than
  283. * region_size.
  284. */
  285. from.count = ms->ti->len & (region_size - 1);
  286. if (!from.count)
  287. from.count = region_size;
  288. } else
  289. from.count = region_size;
  290. /* fill in the destinations */
  291. for (i = 0, dest = to; i < ms->nr_mirrors; i++) {
  292. if (&ms->mirror[i] == get_default_mirror(ms))
  293. continue;
  294. m = ms->mirror + i;
  295. dest->bdev = m->dev->bdev;
  296. dest->sector = m->offset + dm_rh_region_to_sector(ms->rh, key);
  297. dest->count = from.count;
  298. dest++;
  299. }
  300. /* hand to kcopyd */
  301. if (!errors_handled(ms))
  302. flags |= BIT(DM_KCOPYD_IGNORE_ERROR);
  303. dm_kcopyd_copy(ms->kcopyd_client, &from, ms->nr_mirrors - 1, to,
  304. flags, recovery_complete, reg);
  305. }
  306. static void reset_ms_flags(struct mirror_set *ms)
  307. {
  308. unsigned int m;
  309. ms->leg_failure = 0;
  310. for (m = 0; m < ms->nr_mirrors; m++) {
  311. atomic_set(&(ms->mirror[m].error_count), 0);
  312. ms->mirror[m].error_type = 0;
  313. }
  314. }
  315. static void do_recovery(struct mirror_set *ms)
  316. {
  317. struct dm_region *reg;
  318. struct dm_dirty_log *log = dm_rh_dirty_log(ms->rh);
  319. /*
  320. * Start quiescing some regions.
  321. */
  322. dm_rh_recovery_prepare(ms->rh);
  323. /*
  324. * Copy any already quiesced regions.
  325. */
  326. while ((reg = dm_rh_recovery_start(ms->rh)))
  327. recover(ms, reg);
  328. /*
  329. * Update the in sync flag.
  330. */
  331. if (!ms->in_sync &&
  332. (log->type->get_sync_count(log) == ms->nr_regions)) {
  333. /* the sync is complete */
  334. dm_table_event(ms->ti->table);
  335. ms->in_sync = 1;
  336. reset_ms_flags(ms);
  337. }
  338. }
  339. /*-----------------------------------------------------------------
  340. * Reads
  341. *---------------------------------------------------------------*/
  342. static struct mirror *choose_mirror(struct mirror_set *ms, sector_t sector)
  343. {
  344. struct mirror *m = get_default_mirror(ms);
  345. do {
  346. if (likely(!atomic_read(&m->error_count)))
  347. return m;
  348. if (m-- == ms->mirror)
  349. m += ms->nr_mirrors;
  350. } while (m != get_default_mirror(ms));
  351. return NULL;
  352. }
  353. static int default_ok(struct mirror *m)
  354. {
  355. struct mirror *default_mirror = get_default_mirror(m->ms);
  356. return !atomic_read(&default_mirror->error_count);
  357. }
  358. static int mirror_available(struct mirror_set *ms, struct bio *bio)
  359. {
  360. struct dm_dirty_log *log = dm_rh_dirty_log(ms->rh);
  361. region_t region = dm_rh_bio_to_region(ms->rh, bio);
  362. if (log->type->in_sync(log, region, 0))
  363. return choose_mirror(ms, bio->bi_iter.bi_sector) ? 1 : 0;
  364. return 0;
  365. }
  366. /*
  367. * remap a buffer to a particular mirror.
  368. */
  369. static sector_t map_sector(struct mirror *m, struct bio *bio)
  370. {
  371. if (unlikely(!bio->bi_iter.bi_size))
  372. return 0;
  373. return m->offset + dm_target_offset(m->ms->ti, bio->bi_iter.bi_sector);
  374. }
  375. static void map_bio(struct mirror *m, struct bio *bio)
  376. {
  377. bio_set_dev(bio, m->dev->bdev);
  378. bio->bi_iter.bi_sector = map_sector(m, bio);
  379. }
  380. static void map_region(struct dm_io_region *io, struct mirror *m,
  381. struct bio *bio)
  382. {
  383. io->bdev = m->dev->bdev;
  384. io->sector = map_sector(m, bio);
  385. io->count = bio_sectors(bio);
  386. }
  387. static void hold_bio(struct mirror_set *ms, struct bio *bio)
  388. {
  389. /*
  390. * Lock is required to avoid race condition during suspend
  391. * process.
  392. */
  393. spin_lock_irq(&ms->lock);
  394. if (atomic_read(&ms->suspend)) {
  395. spin_unlock_irq(&ms->lock);
  396. /*
  397. * If device is suspended, complete the bio.
  398. */
  399. if (dm_noflush_suspending(ms->ti))
  400. bio->bi_status = BLK_STS_DM_REQUEUE;
  401. else
  402. bio->bi_status = BLK_STS_IOERR;
  403. bio_endio(bio);
  404. return;
  405. }
  406. /*
  407. * Hold bio until the suspend is complete.
  408. */
  409. bio_list_add(&ms->holds, bio);
  410. spin_unlock_irq(&ms->lock);
  411. }
  412. /*-----------------------------------------------------------------
  413. * Reads
  414. *---------------------------------------------------------------*/
  415. static void read_callback(unsigned long error, void *context)
  416. {
  417. struct bio *bio = context;
  418. struct mirror *m;
  419. m = bio_get_m(bio);
  420. bio_set_m(bio, NULL);
  421. if (likely(!error)) {
  422. bio_endio(bio);
  423. return;
  424. }
  425. fail_mirror(m, DM_RAID1_READ_ERROR);
  426. if (likely(default_ok(m)) || mirror_available(m->ms, bio)) {
  427. DMWARN_LIMIT("Read failure on mirror device %s. Trying alternative device.",
  428. m->dev->name);
  429. queue_bio(m->ms, bio, bio_data_dir(bio));
  430. return;
  431. }
  432. DMERR_LIMIT("Read failure on mirror device %s. Failing I/O.",
  433. m->dev->name);
  434. bio_io_error(bio);
  435. }
  436. /* Asynchronous read. */
  437. static void read_async_bio(struct mirror *m, struct bio *bio)
  438. {
  439. struct dm_io_region io;
  440. struct dm_io_request io_req = {
  441. .bi_opf = REQ_OP_READ,
  442. .mem.type = DM_IO_BIO,
  443. .mem.ptr.bio = bio,
  444. .notify.fn = read_callback,
  445. .notify.context = bio,
  446. .client = m->ms->io_client,
  447. };
  448. map_region(&io, m, bio);
  449. bio_set_m(bio, m);
  450. BUG_ON(dm_io(&io_req, 1, &io, NULL));
  451. }
  452. static inline int region_in_sync(struct mirror_set *ms, region_t region,
  453. int may_block)
  454. {
  455. int state = dm_rh_get_state(ms->rh, region, may_block);
  456. return state == DM_RH_CLEAN || state == DM_RH_DIRTY;
  457. }
  458. static void do_reads(struct mirror_set *ms, struct bio_list *reads)
  459. {
  460. region_t region;
  461. struct bio *bio;
  462. struct mirror *m;
  463. while ((bio = bio_list_pop(reads))) {
  464. region = dm_rh_bio_to_region(ms->rh, bio);
  465. m = get_default_mirror(ms);
  466. /*
  467. * We can only read balance if the region is in sync.
  468. */
  469. if (likely(region_in_sync(ms, region, 1)))
  470. m = choose_mirror(ms, bio->bi_iter.bi_sector);
  471. else if (m && atomic_read(&m->error_count))
  472. m = NULL;
  473. if (likely(m))
  474. read_async_bio(m, bio);
  475. else
  476. bio_io_error(bio);
  477. }
  478. }
  479. /*-----------------------------------------------------------------
  480. * Writes.
  481. *
  482. * We do different things with the write io depending on the
  483. * state of the region that it's in:
  484. *
  485. * SYNC: increment pending, use kcopyd to write to *all* mirrors
  486. * RECOVERING: delay the io until recovery completes
  487. * NOSYNC: increment pending, just write to the default mirror
  488. *---------------------------------------------------------------*/
  489. static void write_callback(unsigned long error, void *context)
  490. {
  491. unsigned int i;
  492. struct bio *bio = (struct bio *) context;
  493. struct mirror_set *ms;
  494. int should_wake = 0;
  495. unsigned long flags;
  496. ms = bio_get_m(bio)->ms;
  497. bio_set_m(bio, NULL);
  498. /*
  499. * NOTE: We don't decrement the pending count here,
  500. * instead it is done by the targets endio function.
  501. * This way we handle both writes to SYNC and NOSYNC
  502. * regions with the same code.
  503. */
  504. if (likely(!error)) {
  505. bio_endio(bio);
  506. return;
  507. }
  508. /*
  509. * If the bio is discard, return an error, but do not
  510. * degrade the array.
  511. */
  512. if (bio_op(bio) == REQ_OP_DISCARD) {
  513. bio->bi_status = BLK_STS_NOTSUPP;
  514. bio_endio(bio);
  515. return;
  516. }
  517. for (i = 0; i < ms->nr_mirrors; i++)
  518. if (test_bit(i, &error))
  519. fail_mirror(ms->mirror + i, DM_RAID1_WRITE_ERROR);
  520. /*
  521. * Need to raise event. Since raising
  522. * events can block, we need to do it in
  523. * the main thread.
  524. */
  525. spin_lock_irqsave(&ms->lock, flags);
  526. if (!ms->failures.head)
  527. should_wake = 1;
  528. bio_list_add(&ms->failures, bio);
  529. spin_unlock_irqrestore(&ms->lock, flags);
  530. if (should_wake)
  531. wakeup_mirrord(ms);
  532. }
  533. static void do_write(struct mirror_set *ms, struct bio *bio)
  534. {
  535. unsigned int i;
  536. struct dm_io_region io[MAX_NR_MIRRORS], *dest = io;
  537. struct mirror *m;
  538. blk_opf_t op_flags = bio->bi_opf & (REQ_FUA | REQ_PREFLUSH);
  539. struct dm_io_request io_req = {
  540. .bi_opf = REQ_OP_WRITE | op_flags,
  541. .mem.type = DM_IO_BIO,
  542. .mem.ptr.bio = bio,
  543. .notify.fn = write_callback,
  544. .notify.context = bio,
  545. .client = ms->io_client,
  546. };
  547. if (bio_op(bio) == REQ_OP_DISCARD) {
  548. io_req.bi_opf = REQ_OP_DISCARD | op_flags;
  549. io_req.mem.type = DM_IO_KMEM;
  550. io_req.mem.ptr.addr = NULL;
  551. }
  552. for (i = 0, m = ms->mirror; i < ms->nr_mirrors; i++, m++)
  553. map_region(dest++, m, bio);
  554. /*
  555. * Use default mirror because we only need it to retrieve the reference
  556. * to the mirror set in write_callback().
  557. */
  558. bio_set_m(bio, get_default_mirror(ms));
  559. BUG_ON(dm_io(&io_req, ms->nr_mirrors, io, NULL));
  560. }
  561. static void do_writes(struct mirror_set *ms, struct bio_list *writes)
  562. {
  563. int state;
  564. struct bio *bio;
  565. struct bio_list sync, nosync, recover, *this_list = NULL;
  566. struct bio_list requeue;
  567. struct dm_dirty_log *log = dm_rh_dirty_log(ms->rh);
  568. region_t region;
  569. if (!writes->head)
  570. return;
  571. /*
  572. * Classify each write.
  573. */
  574. bio_list_init(&sync);
  575. bio_list_init(&nosync);
  576. bio_list_init(&recover);
  577. bio_list_init(&requeue);
  578. while ((bio = bio_list_pop(writes))) {
  579. if ((bio->bi_opf & REQ_PREFLUSH) ||
  580. (bio_op(bio) == REQ_OP_DISCARD)) {
  581. bio_list_add(&sync, bio);
  582. continue;
  583. }
  584. region = dm_rh_bio_to_region(ms->rh, bio);
  585. if (log->type->is_remote_recovering &&
  586. log->type->is_remote_recovering(log, region)) {
  587. bio_list_add(&requeue, bio);
  588. continue;
  589. }
  590. state = dm_rh_get_state(ms->rh, region, 1);
  591. switch (state) {
  592. case DM_RH_CLEAN:
  593. case DM_RH_DIRTY:
  594. this_list = &sync;
  595. break;
  596. case DM_RH_NOSYNC:
  597. this_list = &nosync;
  598. break;
  599. case DM_RH_RECOVERING:
  600. this_list = &recover;
  601. break;
  602. }
  603. bio_list_add(this_list, bio);
  604. }
  605. /*
  606. * Add bios that are delayed due to remote recovery
  607. * back on to the write queue
  608. */
  609. if (unlikely(requeue.head)) {
  610. spin_lock_irq(&ms->lock);
  611. bio_list_merge(&ms->writes, &requeue);
  612. spin_unlock_irq(&ms->lock);
  613. delayed_wake(ms);
  614. }
  615. /*
  616. * Increment the pending counts for any regions that will
  617. * be written to (writes to recover regions are going to
  618. * be delayed).
  619. */
  620. dm_rh_inc_pending(ms->rh, &sync);
  621. dm_rh_inc_pending(ms->rh, &nosync);
  622. /*
  623. * If the flush fails on a previous call and succeeds here,
  624. * we must not reset the log_failure variable. We need
  625. * userspace interaction to do that.
  626. */
  627. ms->log_failure = dm_rh_flush(ms->rh) ? 1 : ms->log_failure;
  628. /*
  629. * Dispatch io.
  630. */
  631. if (unlikely(ms->log_failure) && errors_handled(ms)) {
  632. spin_lock_irq(&ms->lock);
  633. bio_list_merge(&ms->failures, &sync);
  634. spin_unlock_irq(&ms->lock);
  635. wakeup_mirrord(ms);
  636. } else
  637. while ((bio = bio_list_pop(&sync)))
  638. do_write(ms, bio);
  639. while ((bio = bio_list_pop(&recover)))
  640. dm_rh_delay(ms->rh, bio);
  641. while ((bio = bio_list_pop(&nosync))) {
  642. if (unlikely(ms->leg_failure) && errors_handled(ms) && !keep_log(ms)) {
  643. spin_lock_irq(&ms->lock);
  644. bio_list_add(&ms->failures, bio);
  645. spin_unlock_irq(&ms->lock);
  646. wakeup_mirrord(ms);
  647. } else {
  648. map_bio(get_default_mirror(ms), bio);
  649. submit_bio_noacct(bio);
  650. }
  651. }
  652. }
  653. static void do_failures(struct mirror_set *ms, struct bio_list *failures)
  654. {
  655. struct bio *bio;
  656. if (likely(!failures->head))
  657. return;
  658. /*
  659. * If the log has failed, unattempted writes are being
  660. * put on the holds list. We can't issue those writes
  661. * until a log has been marked, so we must store them.
  662. *
  663. * If a 'noflush' suspend is in progress, we can requeue
  664. * the I/O's to the core. This give userspace a chance
  665. * to reconfigure the mirror, at which point the core
  666. * will reissue the writes. If the 'noflush' flag is
  667. * not set, we have no choice but to return errors.
  668. *
  669. * Some writes on the failures list may have been
  670. * submitted before the log failure and represent a
  671. * failure to write to one of the devices. It is ok
  672. * for us to treat them the same and requeue them
  673. * as well.
  674. */
  675. while ((bio = bio_list_pop(failures))) {
  676. if (!ms->log_failure) {
  677. ms->in_sync = 0;
  678. dm_rh_mark_nosync(ms->rh, bio);
  679. }
  680. /*
  681. * If all the legs are dead, fail the I/O.
  682. * If the device has failed and keep_log is enabled,
  683. * fail the I/O.
  684. *
  685. * If we have been told to handle errors, and keep_log
  686. * isn't enabled, hold the bio and wait for userspace to
  687. * deal with the problem.
  688. *
  689. * Otherwise pretend that the I/O succeeded. (This would
  690. * be wrong if the failed leg returned after reboot and
  691. * got replicated back to the good legs.)
  692. */
  693. if (unlikely(!get_valid_mirror(ms) || (keep_log(ms) && ms->log_failure)))
  694. bio_io_error(bio);
  695. else if (errors_handled(ms) && !keep_log(ms))
  696. hold_bio(ms, bio);
  697. else
  698. bio_endio(bio);
  699. }
  700. }
  701. static void trigger_event(struct work_struct *work)
  702. {
  703. struct mirror_set *ms =
  704. container_of(work, struct mirror_set, trigger_event);
  705. dm_table_event(ms->ti->table);
  706. }
  707. /*-----------------------------------------------------------------
  708. * kmirrord
  709. *---------------------------------------------------------------*/
  710. static void do_mirror(struct work_struct *work)
  711. {
  712. struct mirror_set *ms = container_of(work, struct mirror_set,
  713. kmirrord_work);
  714. struct bio_list reads, writes, failures;
  715. unsigned long flags;
  716. spin_lock_irqsave(&ms->lock, flags);
  717. reads = ms->reads;
  718. writes = ms->writes;
  719. failures = ms->failures;
  720. bio_list_init(&ms->reads);
  721. bio_list_init(&ms->writes);
  722. bio_list_init(&ms->failures);
  723. spin_unlock_irqrestore(&ms->lock, flags);
  724. dm_rh_update_states(ms->rh, errors_handled(ms));
  725. do_recovery(ms);
  726. do_reads(ms, &reads);
  727. do_writes(ms, &writes);
  728. do_failures(ms, &failures);
  729. }
  730. /*-----------------------------------------------------------------
  731. * Target functions
  732. *---------------------------------------------------------------*/
  733. static struct mirror_set *alloc_context(unsigned int nr_mirrors,
  734. uint32_t region_size,
  735. struct dm_target *ti,
  736. struct dm_dirty_log *dl)
  737. {
  738. struct mirror_set *ms =
  739. kzalloc(struct_size(ms, mirror, nr_mirrors), GFP_KERNEL);
  740. if (!ms) {
  741. ti->error = "Cannot allocate mirror context";
  742. return NULL;
  743. }
  744. spin_lock_init(&ms->lock);
  745. bio_list_init(&ms->reads);
  746. bio_list_init(&ms->writes);
  747. bio_list_init(&ms->failures);
  748. bio_list_init(&ms->holds);
  749. ms->ti = ti;
  750. ms->nr_mirrors = nr_mirrors;
  751. ms->nr_regions = dm_sector_div_up(ti->len, region_size);
  752. ms->in_sync = 0;
  753. ms->log_failure = 0;
  754. ms->leg_failure = 0;
  755. atomic_set(&ms->suspend, 0);
  756. atomic_set(&ms->default_mirror, DEFAULT_MIRROR);
  757. ms->io_client = dm_io_client_create();
  758. if (IS_ERR(ms->io_client)) {
  759. ti->error = "Error creating dm_io client";
  760. kfree(ms);
  761. return NULL;
  762. }
  763. ms->rh = dm_region_hash_create(ms, dispatch_bios, wakeup_mirrord,
  764. wakeup_all_recovery_waiters,
  765. ms->ti->begin, MAX_RECOVERY,
  766. dl, region_size, ms->nr_regions);
  767. if (IS_ERR(ms->rh)) {
  768. ti->error = "Error creating dirty region hash";
  769. dm_io_client_destroy(ms->io_client);
  770. kfree(ms);
  771. return NULL;
  772. }
  773. return ms;
  774. }
  775. static void free_context(struct mirror_set *ms, struct dm_target *ti,
  776. unsigned int m)
  777. {
  778. while (m--)
  779. dm_put_device(ti, ms->mirror[m].dev);
  780. dm_io_client_destroy(ms->io_client);
  781. dm_region_hash_destroy(ms->rh);
  782. kfree(ms);
  783. }
  784. static int get_mirror(struct mirror_set *ms, struct dm_target *ti,
  785. unsigned int mirror, char **argv)
  786. {
  787. unsigned long long offset;
  788. char dummy;
  789. int ret;
  790. if (sscanf(argv[1], "%llu%c", &offset, &dummy) != 1 ||
  791. offset != (sector_t)offset) {
  792. ti->error = "Invalid offset";
  793. return -EINVAL;
  794. }
  795. ret = dm_get_device(ti, argv[0], dm_table_get_mode(ti->table),
  796. &ms->mirror[mirror].dev);
  797. if (ret) {
  798. ti->error = "Device lookup failure";
  799. return ret;
  800. }
  801. ms->mirror[mirror].ms = ms;
  802. atomic_set(&(ms->mirror[mirror].error_count), 0);
  803. ms->mirror[mirror].error_type = 0;
  804. ms->mirror[mirror].offset = offset;
  805. return 0;
  806. }
  807. /*
  808. * Create dirty log: log_type #log_params <log_params>
  809. */
  810. static struct dm_dirty_log *create_dirty_log(struct dm_target *ti,
  811. unsigned int argc, char **argv,
  812. unsigned int *args_used)
  813. {
  814. unsigned int param_count;
  815. struct dm_dirty_log *dl;
  816. char dummy;
  817. if (argc < 2) {
  818. ti->error = "Insufficient mirror log arguments";
  819. return NULL;
  820. }
  821. if (sscanf(argv[1], "%u%c", &param_count, &dummy) != 1) {
  822. ti->error = "Invalid mirror log argument count";
  823. return NULL;
  824. }
  825. *args_used = 2 + param_count;
  826. if (argc < *args_used) {
  827. ti->error = "Insufficient mirror log arguments";
  828. return NULL;
  829. }
  830. dl = dm_dirty_log_create(argv[0], ti, mirror_flush, param_count,
  831. argv + 2);
  832. if (!dl) {
  833. ti->error = "Error creating mirror dirty log";
  834. return NULL;
  835. }
  836. return dl;
  837. }
  838. static int parse_features(struct mirror_set *ms, unsigned int argc, char **argv,
  839. unsigned int *args_used)
  840. {
  841. unsigned int num_features;
  842. struct dm_target *ti = ms->ti;
  843. char dummy;
  844. int i;
  845. *args_used = 0;
  846. if (!argc)
  847. return 0;
  848. if (sscanf(argv[0], "%u%c", &num_features, &dummy) != 1) {
  849. ti->error = "Invalid number of features";
  850. return -EINVAL;
  851. }
  852. argc--;
  853. argv++;
  854. (*args_used)++;
  855. if (num_features > argc) {
  856. ti->error = "Not enough arguments to support feature count";
  857. return -EINVAL;
  858. }
  859. for (i = 0; i < num_features; i++) {
  860. if (!strcmp("handle_errors", argv[0]))
  861. ms->features |= DM_RAID1_HANDLE_ERRORS;
  862. else if (!strcmp("keep_log", argv[0]))
  863. ms->features |= DM_RAID1_KEEP_LOG;
  864. else {
  865. ti->error = "Unrecognised feature requested";
  866. return -EINVAL;
  867. }
  868. argc--;
  869. argv++;
  870. (*args_used)++;
  871. }
  872. if (!errors_handled(ms) && keep_log(ms)) {
  873. ti->error = "keep_log feature requires the handle_errors feature";
  874. return -EINVAL;
  875. }
  876. return 0;
  877. }
  878. /*
  879. * Construct a mirror mapping:
  880. *
  881. * log_type #log_params <log_params>
  882. * #mirrors [mirror_path offset]{2,}
  883. * [#features <features>]
  884. *
  885. * log_type is "core" or "disk"
  886. * #log_params is between 1 and 3
  887. *
  888. * If present, supported features are "handle_errors" and "keep_log".
  889. */
  890. static int mirror_ctr(struct dm_target *ti, unsigned int argc, char **argv)
  891. {
  892. int r;
  893. unsigned int nr_mirrors, m, args_used;
  894. struct mirror_set *ms;
  895. struct dm_dirty_log *dl;
  896. char dummy;
  897. dl = create_dirty_log(ti, argc, argv, &args_used);
  898. if (!dl)
  899. return -EINVAL;
  900. argv += args_used;
  901. argc -= args_used;
  902. if (!argc || sscanf(argv[0], "%u%c", &nr_mirrors, &dummy) != 1 ||
  903. nr_mirrors < 2 || nr_mirrors > MAX_NR_MIRRORS) {
  904. ti->error = "Invalid number of mirrors";
  905. dm_dirty_log_destroy(dl);
  906. return -EINVAL;
  907. }
  908. argv++, argc--;
  909. if (argc < nr_mirrors * 2) {
  910. ti->error = "Too few mirror arguments";
  911. dm_dirty_log_destroy(dl);
  912. return -EINVAL;
  913. }
  914. ms = alloc_context(nr_mirrors, dl->type->get_region_size(dl), ti, dl);
  915. if (!ms) {
  916. dm_dirty_log_destroy(dl);
  917. return -ENOMEM;
  918. }
  919. /* Get the mirror parameter sets */
  920. for (m = 0; m < nr_mirrors; m++) {
  921. r = get_mirror(ms, ti, m, argv);
  922. if (r) {
  923. free_context(ms, ti, m);
  924. return r;
  925. }
  926. argv += 2;
  927. argc -= 2;
  928. }
  929. ti->private = ms;
  930. r = dm_set_target_max_io_len(ti, dm_rh_get_region_size(ms->rh));
  931. if (r)
  932. goto err_free_context;
  933. ti->num_flush_bios = 1;
  934. ti->num_discard_bios = 1;
  935. ti->per_io_data_size = sizeof(struct dm_raid1_bio_record);
  936. ms->kmirrord_wq = alloc_workqueue("kmirrord", WQ_MEM_RECLAIM, 0);
  937. if (!ms->kmirrord_wq) {
  938. DMERR("couldn't start kmirrord");
  939. r = -ENOMEM;
  940. goto err_free_context;
  941. }
  942. INIT_WORK(&ms->kmirrord_work, do_mirror);
  943. timer_setup(&ms->timer, delayed_wake_fn, 0);
  944. ms->timer_pending = 0;
  945. INIT_WORK(&ms->trigger_event, trigger_event);
  946. r = parse_features(ms, argc, argv, &args_used);
  947. if (r)
  948. goto err_destroy_wq;
  949. argv += args_used;
  950. argc -= args_used;
  951. /*
  952. * Any read-balancing addition depends on the
  953. * DM_RAID1_HANDLE_ERRORS flag being present.
  954. * This is because the decision to balance depends
  955. * on the sync state of a region. If the above
  956. * flag is not present, we ignore errors; and
  957. * the sync state may be inaccurate.
  958. */
  959. if (argc) {
  960. ti->error = "Too many mirror arguments";
  961. r = -EINVAL;
  962. goto err_destroy_wq;
  963. }
  964. ms->kcopyd_client = dm_kcopyd_client_create(&dm_kcopyd_throttle);
  965. if (IS_ERR(ms->kcopyd_client)) {
  966. r = PTR_ERR(ms->kcopyd_client);
  967. goto err_destroy_wq;
  968. }
  969. wakeup_mirrord(ms);
  970. return 0;
  971. err_destroy_wq:
  972. destroy_workqueue(ms->kmirrord_wq);
  973. err_free_context:
  974. free_context(ms, ti, ms->nr_mirrors);
  975. return r;
  976. }
  977. static void mirror_dtr(struct dm_target *ti)
  978. {
  979. struct mirror_set *ms = (struct mirror_set *) ti->private;
  980. del_timer_sync(&ms->timer);
  981. flush_workqueue(ms->kmirrord_wq);
  982. flush_work(&ms->trigger_event);
  983. dm_kcopyd_client_destroy(ms->kcopyd_client);
  984. destroy_workqueue(ms->kmirrord_wq);
  985. free_context(ms, ti, ms->nr_mirrors);
  986. }
  987. /*
  988. * Mirror mapping function
  989. */
  990. static int mirror_map(struct dm_target *ti, struct bio *bio)
  991. {
  992. int r, rw = bio_data_dir(bio);
  993. struct mirror *m;
  994. struct mirror_set *ms = ti->private;
  995. struct dm_dirty_log *log = dm_rh_dirty_log(ms->rh);
  996. struct dm_raid1_bio_record *bio_record =
  997. dm_per_bio_data(bio, sizeof(struct dm_raid1_bio_record));
  998. bio_record->details.bi_bdev = NULL;
  999. if (rw == WRITE) {
  1000. /* Save region for mirror_end_io() handler */
  1001. bio_record->write_region = dm_rh_bio_to_region(ms->rh, bio);
  1002. queue_bio(ms, bio, rw);
  1003. return DM_MAPIO_SUBMITTED;
  1004. }
  1005. r = log->type->in_sync(log, dm_rh_bio_to_region(ms->rh, bio), 0);
  1006. if (r < 0 && r != -EWOULDBLOCK)
  1007. return DM_MAPIO_KILL;
  1008. /*
  1009. * If region is not in-sync queue the bio.
  1010. */
  1011. if (!r || (r == -EWOULDBLOCK)) {
  1012. if (bio->bi_opf & REQ_RAHEAD)
  1013. return DM_MAPIO_KILL;
  1014. queue_bio(ms, bio, rw);
  1015. return DM_MAPIO_SUBMITTED;
  1016. }
  1017. /*
  1018. * The region is in-sync and we can perform reads directly.
  1019. * Store enough information so we can retry if it fails.
  1020. */
  1021. m = choose_mirror(ms, bio->bi_iter.bi_sector);
  1022. if (unlikely(!m))
  1023. return DM_MAPIO_KILL;
  1024. dm_bio_record(&bio_record->details, bio);
  1025. bio_record->m = m;
  1026. map_bio(m, bio);
  1027. return DM_MAPIO_REMAPPED;
  1028. }
  1029. static int mirror_end_io(struct dm_target *ti, struct bio *bio,
  1030. blk_status_t *error)
  1031. {
  1032. int rw = bio_data_dir(bio);
  1033. struct mirror_set *ms = (struct mirror_set *) ti->private;
  1034. struct mirror *m = NULL;
  1035. struct dm_bio_details *bd = NULL;
  1036. struct dm_raid1_bio_record *bio_record =
  1037. dm_per_bio_data(bio, sizeof(struct dm_raid1_bio_record));
  1038. /*
  1039. * We need to dec pending if this was a write.
  1040. */
  1041. if (rw == WRITE) {
  1042. if (!(bio->bi_opf & REQ_PREFLUSH) &&
  1043. bio_op(bio) != REQ_OP_DISCARD)
  1044. dm_rh_dec(ms->rh, bio_record->write_region);
  1045. return DM_ENDIO_DONE;
  1046. }
  1047. if (*error == BLK_STS_NOTSUPP)
  1048. goto out;
  1049. if (bio->bi_opf & REQ_RAHEAD)
  1050. goto out;
  1051. if (unlikely(*error)) {
  1052. if (!bio_record->details.bi_bdev) {
  1053. /*
  1054. * There wasn't enough memory to record necessary
  1055. * information for a retry or there was no other
  1056. * mirror in-sync.
  1057. */
  1058. DMERR_LIMIT("Mirror read failed.");
  1059. return DM_ENDIO_DONE;
  1060. }
  1061. m = bio_record->m;
  1062. DMERR("Mirror read failed from %s. Trying alternative device.",
  1063. m->dev->name);
  1064. fail_mirror(m, DM_RAID1_READ_ERROR);
  1065. /*
  1066. * A failed read is requeued for another attempt using an intact
  1067. * mirror.
  1068. */
  1069. if (default_ok(m) || mirror_available(ms, bio)) {
  1070. bd = &bio_record->details;
  1071. dm_bio_restore(bd, bio);
  1072. bio_record->details.bi_bdev = NULL;
  1073. bio->bi_status = 0;
  1074. queue_bio(ms, bio, rw);
  1075. return DM_ENDIO_INCOMPLETE;
  1076. }
  1077. DMERR("All replicated volumes dead, failing I/O");
  1078. }
  1079. out:
  1080. bio_record->details.bi_bdev = NULL;
  1081. return DM_ENDIO_DONE;
  1082. }
  1083. static void mirror_presuspend(struct dm_target *ti)
  1084. {
  1085. struct mirror_set *ms = (struct mirror_set *) ti->private;
  1086. struct dm_dirty_log *log = dm_rh_dirty_log(ms->rh);
  1087. struct bio_list holds;
  1088. struct bio *bio;
  1089. atomic_set(&ms->suspend, 1);
  1090. /*
  1091. * Process bios in the hold list to start recovery waiting
  1092. * for bios in the hold list. After the process, no bio has
  1093. * a chance to be added in the hold list because ms->suspend
  1094. * is set.
  1095. */
  1096. spin_lock_irq(&ms->lock);
  1097. holds = ms->holds;
  1098. bio_list_init(&ms->holds);
  1099. spin_unlock_irq(&ms->lock);
  1100. while ((bio = bio_list_pop(&holds)))
  1101. hold_bio(ms, bio);
  1102. /*
  1103. * We must finish up all the work that we've
  1104. * generated (i.e. recovery work).
  1105. */
  1106. dm_rh_stop_recovery(ms->rh);
  1107. wait_event(_kmirrord_recovery_stopped,
  1108. !dm_rh_recovery_in_flight(ms->rh));
  1109. if (log->type->presuspend && log->type->presuspend(log))
  1110. /* FIXME: need better error handling */
  1111. DMWARN("log presuspend failed");
  1112. /*
  1113. * Now that recovery is complete/stopped and the
  1114. * delayed bios are queued, we need to wait for
  1115. * the worker thread to complete. This way,
  1116. * we know that all of our I/O has been pushed.
  1117. */
  1118. flush_workqueue(ms->kmirrord_wq);
  1119. }
  1120. static void mirror_postsuspend(struct dm_target *ti)
  1121. {
  1122. struct mirror_set *ms = ti->private;
  1123. struct dm_dirty_log *log = dm_rh_dirty_log(ms->rh);
  1124. if (log->type->postsuspend && log->type->postsuspend(log))
  1125. /* FIXME: need better error handling */
  1126. DMWARN("log postsuspend failed");
  1127. }
  1128. static void mirror_resume(struct dm_target *ti)
  1129. {
  1130. struct mirror_set *ms = ti->private;
  1131. struct dm_dirty_log *log = dm_rh_dirty_log(ms->rh);
  1132. atomic_set(&ms->suspend, 0);
  1133. if (log->type->resume && log->type->resume(log))
  1134. /* FIXME: need better error handling */
  1135. DMWARN("log resume failed");
  1136. dm_rh_start_recovery(ms->rh);
  1137. }
  1138. /*
  1139. * device_status_char
  1140. * @m: mirror device/leg we want the status of
  1141. *
  1142. * We return one character representing the most severe error
  1143. * we have encountered.
  1144. * A => Alive - No failures
  1145. * D => Dead - A write failure occurred leaving mirror out-of-sync
  1146. * S => Sync - A sychronization failure occurred, mirror out-of-sync
  1147. * R => Read - A read failure occurred, mirror data unaffected
  1148. *
  1149. * Returns: <char>
  1150. */
  1151. static char device_status_char(struct mirror *m)
  1152. {
  1153. if (!atomic_read(&(m->error_count)))
  1154. return 'A';
  1155. return (test_bit(DM_RAID1_FLUSH_ERROR, &(m->error_type))) ? 'F' :
  1156. (test_bit(DM_RAID1_WRITE_ERROR, &(m->error_type))) ? 'D' :
  1157. (test_bit(DM_RAID1_SYNC_ERROR, &(m->error_type))) ? 'S' :
  1158. (test_bit(DM_RAID1_READ_ERROR, &(m->error_type))) ? 'R' : 'U';
  1159. }
  1160. static void mirror_status(struct dm_target *ti, status_type_t type,
  1161. unsigned int status_flags, char *result, unsigned int maxlen)
  1162. {
  1163. unsigned int m, sz = 0;
  1164. int num_feature_args = 0;
  1165. struct mirror_set *ms = (struct mirror_set *) ti->private;
  1166. struct dm_dirty_log *log = dm_rh_dirty_log(ms->rh);
  1167. char buffer[MAX_NR_MIRRORS + 1];
  1168. switch (type) {
  1169. case STATUSTYPE_INFO:
  1170. DMEMIT("%d ", ms->nr_mirrors);
  1171. for (m = 0; m < ms->nr_mirrors; m++) {
  1172. DMEMIT("%s ", ms->mirror[m].dev->name);
  1173. buffer[m] = device_status_char(&(ms->mirror[m]));
  1174. }
  1175. buffer[m] = '\0';
  1176. DMEMIT("%llu/%llu 1 %s ",
  1177. (unsigned long long)log->type->get_sync_count(log),
  1178. (unsigned long long)ms->nr_regions, buffer);
  1179. sz += log->type->status(log, type, result+sz, maxlen-sz);
  1180. break;
  1181. case STATUSTYPE_TABLE:
  1182. sz = log->type->status(log, type, result, maxlen);
  1183. DMEMIT("%d", ms->nr_mirrors);
  1184. for (m = 0; m < ms->nr_mirrors; m++)
  1185. DMEMIT(" %s %llu", ms->mirror[m].dev->name,
  1186. (unsigned long long)ms->mirror[m].offset);
  1187. num_feature_args += !!errors_handled(ms);
  1188. num_feature_args += !!keep_log(ms);
  1189. if (num_feature_args) {
  1190. DMEMIT(" %d", num_feature_args);
  1191. if (errors_handled(ms))
  1192. DMEMIT(" handle_errors");
  1193. if (keep_log(ms))
  1194. DMEMIT(" keep_log");
  1195. }
  1196. break;
  1197. case STATUSTYPE_IMA:
  1198. DMEMIT_TARGET_NAME_VERSION(ti->type);
  1199. DMEMIT(",nr_mirrors=%d", ms->nr_mirrors);
  1200. for (m = 0; m < ms->nr_mirrors; m++) {
  1201. DMEMIT(",mirror_device_%d=%s", m, ms->mirror[m].dev->name);
  1202. DMEMIT(",mirror_device_%d_status=%c",
  1203. m, device_status_char(&(ms->mirror[m])));
  1204. }
  1205. DMEMIT(",handle_errors=%c", errors_handled(ms) ? 'y' : 'n');
  1206. DMEMIT(",keep_log=%c", keep_log(ms) ? 'y' : 'n');
  1207. DMEMIT(",log_type_status=");
  1208. sz += log->type->status(log, type, result+sz, maxlen-sz);
  1209. DMEMIT(";");
  1210. break;
  1211. }
  1212. }
  1213. static int mirror_iterate_devices(struct dm_target *ti,
  1214. iterate_devices_callout_fn fn, void *data)
  1215. {
  1216. struct mirror_set *ms = ti->private;
  1217. int ret = 0;
  1218. unsigned int i;
  1219. for (i = 0; !ret && i < ms->nr_mirrors; i++)
  1220. ret = fn(ti, ms->mirror[i].dev,
  1221. ms->mirror[i].offset, ti->len, data);
  1222. return ret;
  1223. }
  1224. static struct target_type mirror_target = {
  1225. .name = "mirror",
  1226. .version = {1, 14, 0},
  1227. .module = THIS_MODULE,
  1228. .ctr = mirror_ctr,
  1229. .dtr = mirror_dtr,
  1230. .map = mirror_map,
  1231. .end_io = mirror_end_io,
  1232. .presuspend = mirror_presuspend,
  1233. .postsuspend = mirror_postsuspend,
  1234. .resume = mirror_resume,
  1235. .status = mirror_status,
  1236. .iterate_devices = mirror_iterate_devices,
  1237. };
  1238. static int __init dm_mirror_init(void)
  1239. {
  1240. int r;
  1241. r = dm_register_target(&mirror_target);
  1242. if (r < 0) {
  1243. DMERR("Failed to register mirror target");
  1244. goto bad_target;
  1245. }
  1246. return 0;
  1247. bad_target:
  1248. return r;
  1249. }
  1250. static void __exit dm_mirror_exit(void)
  1251. {
  1252. dm_unregister_target(&mirror_target);
  1253. }
  1254. /* Module hooks */
  1255. module_init(dm_mirror_init);
  1256. module_exit(dm_mirror_exit);
  1257. MODULE_DESCRIPTION(DM_NAME " mirror target");
  1258. MODULE_AUTHOR("Joe Thornber");
  1259. MODULE_LICENSE("GPL");