1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Copyright (C) 2015 Shaohua Li <shli@fb.com>
4  * Copyright (C) 2016 Song Liu <songliubraving@fb.com>
5  */
6 #include <linux/kernel.h>
7 #include <linux/wait.h>
8 #include <linux/blkdev.h>
9 #include <linux/slab.h>
10 #include <linux/raid/md_p.h>
11 #include <linux/crc32c.h>
12 #include <linux/random.h>
13 #include <linux/kthread.h>
14 #include <linux/types.h>
15 #include "md.h"
16 #include "raid5.h"
17 #include "md-bitmap.h"
18 #include "raid5-log.h"
19 
20 /*
21  * metadata/data stored in disk with 4k size unit (a block) regardless
22  * underneath hardware sector size. only works with PAGE_SIZE == 4096
23  */
24 #define BLOCK_SECTORS (8)
25 #define BLOCK_SECTOR_SHIFT (3)
26 
27 /*
28  * log->max_free_space is min(1/4 disk size, 10G reclaimable space).
29  *
30  * In write through mode, the reclaim runs every log->max_free_space.
31  * This can prevent the recovery scans for too long
32  */
33 #define RECLAIM_MAX_FREE_SPACE (10 * 1024 * 1024 * 2) /* sector */
34 #define RECLAIM_MAX_FREE_SPACE_SHIFT (2)
35 
36 /* wake up reclaim thread periodically */
37 #define R5C_RECLAIM_WAKEUP_INTERVAL (30 * HZ)
38 /* start flush with these full stripes */
39 #define R5C_FULL_STRIPE_FLUSH_BATCH(conf) (conf->max_nr_stripes / 4)
40 /* reclaim stripes in groups */
41 #define R5C_RECLAIM_STRIPE_GROUP (NR_STRIPE_HASH_LOCKS * 2)
42 
43 /*
44  * We only need 2 bios per I/O unit to make progress, but ensure we
45  * have a few more available to not get too tight.
46  */
47 #define R5L_POOL_SIZE	4
48 
49 static char *r5c_journal_mode_str[] = {"write-through",
50 				       "write-back"};
51 /*
52  * raid5 cache state machine
53  *
54  * With the RAID cache, each stripe works in two phases:
55  *	- caching phase
56  *	- writing-out phase
57  *
58  * These two phases are controlled by bit STRIPE_R5C_CACHING:
59  *   if STRIPE_R5C_CACHING == 0, the stripe is in writing-out phase
60  *   if STRIPE_R5C_CACHING == 1, the stripe is in caching phase
61  *
62  * When there is no journal, or the journal is in write-through mode,
63  * the stripe is always in writing-out phase.
64  *
65  * For write-back journal, the stripe is sent to caching phase on write
66  * (r5c_try_caching_write). r5c_make_stripe_write_out() kicks off
67  * the write-out phase by clearing STRIPE_R5C_CACHING.
68  *
69  * Stripes in caching phase do not write the raid disks. Instead, all
70  * writes are committed from the log device. Therefore, a stripe in
71  * caching phase handles writes as:
72  *	- write to log device
73  *	- return IO
74  *
75  * Stripes in writing-out phase handle writes as:
76  *	- calculate parity
77  *	- write pending data and parity to journal
78  *	- write data and parity to raid disks
79  *	- return IO for pending writes
80  */
81 
82 struct r5l_log {
83 	struct md_rdev *rdev;
84 
85 	u32 uuid_checksum;
86 
87 	sector_t device_size;		/* log device size, round to
88 					 * BLOCK_SECTORS */
89 	sector_t max_free_space;	/* reclaim run if free space is at
90 					 * this size */
91 
92 	sector_t last_checkpoint;	/* log tail. where recovery scan
93 					 * starts from */
94 	u64 last_cp_seq;		/* log tail sequence */
95 
96 	sector_t log_start;		/* log head. where new data appends */
97 	u64 seq;			/* log head sequence */
98 
99 	sector_t next_checkpoint;
100 
101 	struct mutex io_mutex;
102 	struct r5l_io_unit *current_io;	/* current io_unit accepting new data */
103 
104 	spinlock_t io_list_lock;
105 	struct list_head running_ios;	/* io_units which are still running,
106 					 * and have not yet been completely
107 					 * written to the log */
108 	struct list_head io_end_ios;	/* io_units which have been completely
109 					 * written to the log but not yet written
110 					 * to the RAID */
111 	struct list_head flushing_ios;	/* io_units which are waiting for log
112 					 * cache flush */
113 	struct list_head finished_ios;	/* io_units which settle down in log disk */
114 	struct bio flush_bio;
115 
116 	struct list_head no_mem_stripes;   /* pending stripes, -ENOMEM */
117 
118 	struct kmem_cache *io_kc;
119 	mempool_t io_pool;
120 	struct bio_set bs;
121 	mempool_t meta_pool;
122 
123 	struct md_thread __rcu *reclaim_thread;
124 	unsigned long reclaim_target;	/* number of space that need to be
125 					 * reclaimed.  if it's 0, reclaim spaces
126 					 * used by io_units which are in
127 					 * IO_UNIT_STRIPE_END state (eg, reclaim
128 					 * doesn't wait for specific io_unit
129 					 * switching to IO_UNIT_STRIPE_END
130 					 * state) */
131 	wait_queue_head_t iounit_wait;
132 
133 	struct list_head no_space_stripes; /* pending stripes, log has no space */
134 	spinlock_t no_space_stripes_lock;
135 
136 	bool need_cache_flush;
137 
138 	/* for r5c_cache */
139 	enum r5c_journal_mode r5c_journal_mode;
140 
141 	/* all stripes in r5cache, in the order of seq at sh->log_start */
142 	struct list_head stripe_in_journal_list;
143 
144 	spinlock_t stripe_in_journal_lock;
145 	atomic_t stripe_in_journal_count;
146 
147 	/* to submit async io_units, to fulfill ordering of flush */
148 	struct work_struct deferred_io_work;
149 	/* to disable write back during in degraded mode */
150 	struct work_struct disable_writeback_work;
151 
152 	/* to for chunk_aligned_read in writeback mode, details below */
153 	spinlock_t tree_lock;
154 	struct radix_tree_root big_stripe_tree;
155 };
156 
157 /*
158  * Enable chunk_aligned_read() with write back cache.
159  *
160  * Each chunk may contain more than one stripe (for example, a 256kB
161  * chunk contains 64 4kB-page, so this chunk contain 64 stripes). For
162  * chunk_aligned_read, these stripes are grouped into one "big_stripe".
163  * For each big_stripe, we count how many stripes of this big_stripe
164  * are in the write back cache. These data are tracked in a radix tree
165  * (big_stripe_tree). We use radix_tree item pointer as the counter.
166  * r5c_tree_index() is used to calculate keys for the radix tree.
167  *
168  * chunk_aligned_read() calls r5c_big_stripe_cached() to look up
169  * big_stripe of each chunk in the tree. If this big_stripe is in the
170  * tree, chunk_aligned_read() aborts. This look up is protected by
171  * rcu_read_lock().
172  *
173  * It is necessary to remember whether a stripe is counted in
174  * big_stripe_tree. Instead of adding new flag, we reuses existing flags:
175  * STRIPE_R5C_PARTIAL_STRIPE and STRIPE_R5C_FULL_STRIPE. If either of these
176  * two flags are set, the stripe is counted in big_stripe_tree. This
177  * requires moving set_bit(STRIPE_R5C_PARTIAL_STRIPE) to
178  * r5c_try_caching_write(); and moving clear_bit of
179  * STRIPE_R5C_PARTIAL_STRIPE and STRIPE_R5C_FULL_STRIPE to
180  * r5c_finish_stripe_write_out().
181  */
182 
183 /*
184  * radix tree requests lowest 2 bits of data pointer to be 2b'00.
185  * So it is necessary to left shift the counter by 2 bits before using it
186  * as data pointer of the tree.
187  */
188 #define R5C_RADIX_COUNT_SHIFT 2
189 
190 /*
191  * calculate key for big_stripe_tree
192  *
193  * sect: align_bi->bi_iter.bi_sector or sh->sector
194  */
r5c_tree_index(struct r5conf * conf,sector_t sect)195 static inline sector_t r5c_tree_index(struct r5conf *conf,
196 				      sector_t sect)
197 {
198 	sector_div(sect, conf->chunk_sectors);
199 	return sect;
200 }
201 
202 /*
203  * an IO range starts from a meta data block and end at the next meta data
204  * block. The io unit's the meta data block tracks data/parity followed it. io
205  * unit is written to log disk with normal write, as we always flush log disk
206  * first and then start move data to raid disks, there is no requirement to
207  * write io unit with FLUSH/FUA
208  */
209 struct r5l_io_unit {
210 	struct r5l_log *log;
211 
212 	struct page *meta_page;	/* store meta block */
213 	int meta_offset;	/* current offset in meta_page */
214 
215 	struct bio *current_bio;/* current_bio accepting new data */
216 
217 	atomic_t pending_stripe;/* how many stripes not flushed to raid */
218 	u64 seq;		/* seq number of the metablock */
219 	sector_t log_start;	/* where the io_unit starts */
220 	sector_t log_end;	/* where the io_unit ends */
221 	struct list_head log_sibling; /* log->running_ios */
222 	struct list_head stripe_list; /* stripes added to the io_unit */
223 
224 	int state;
225 	bool need_split_bio;
226 	struct bio *split_bio;
227 
228 	unsigned int has_flush:1;		/* include flush request */
229 	unsigned int has_fua:1;			/* include fua request */
230 	unsigned int has_null_flush:1;		/* include null flush request */
231 	unsigned int has_flush_payload:1;	/* include flush payload  */
232 	/*
233 	 * io isn't sent yet, flush/fua request can only be submitted till it's
234 	 * the first IO in running_ios list
235 	 */
236 	unsigned int io_deferred:1;
237 
238 	struct bio_list flush_barriers;   /* size == 0 flush bios */
239 };
240 
241 /* r5l_io_unit state */
242 enum r5l_io_unit_state {
243 	IO_UNIT_RUNNING = 0,	/* accepting new IO */
244 	IO_UNIT_IO_START = 1,	/* io_unit bio start writing to log,
245 				 * don't accepting new bio */
246 	IO_UNIT_IO_END = 2,	/* io_unit bio finish writing to log */
247 	IO_UNIT_STRIPE_END = 3,	/* stripes data finished writing to raid */
248 };
249 
r5c_is_writeback(struct r5l_log * log)250 bool r5c_is_writeback(struct r5l_log *log)
251 {
252 	return (log != NULL &&
253 		log->r5c_journal_mode == R5C_JOURNAL_MODE_WRITE_BACK);
254 }
255 
r5l_ring_add(struct r5l_log * log,sector_t start,sector_t inc)256 static sector_t r5l_ring_add(struct r5l_log *log, sector_t start, sector_t inc)
257 {
258 	start += inc;
259 	if (start >= log->device_size)
260 		start = start - log->device_size;
261 	return start;
262 }
263 
r5l_ring_distance(struct r5l_log * log,sector_t start,sector_t end)264 static sector_t r5l_ring_distance(struct r5l_log *log, sector_t start,
265 				  sector_t end)
266 {
267 	if (end >= start)
268 		return end - start;
269 	else
270 		return end + log->device_size - start;
271 }
272 
r5l_has_free_space(struct r5l_log * log,sector_t size)273 static bool r5l_has_free_space(struct r5l_log *log, sector_t size)
274 {
275 	sector_t used_size;
276 
277 	used_size = r5l_ring_distance(log, log->last_checkpoint,
278 					log->log_start);
279 
280 	return log->device_size > used_size + size;
281 }
282 
__r5l_set_io_unit_state(struct r5l_io_unit * io,enum r5l_io_unit_state state)283 static void __r5l_set_io_unit_state(struct r5l_io_unit *io,
284 				    enum r5l_io_unit_state state)
285 {
286 	if (WARN_ON(io->state >= state))
287 		return;
288 	io->state = state;
289 }
290 
291 static void
r5c_return_dev_pending_writes(struct r5conf * conf,struct r5dev * dev)292 r5c_return_dev_pending_writes(struct r5conf *conf, struct r5dev *dev)
293 {
294 	struct bio *wbi, *wbi2;
295 
296 	wbi = dev->written;
297 	dev->written = NULL;
298 	while (wbi && wbi->bi_iter.bi_sector <
299 	       dev->sector + RAID5_STRIPE_SECTORS(conf)) {
300 		wbi2 = r5_next_bio(conf, wbi, dev->sector);
301 		md_write_end(conf->mddev);
302 		bio_endio(wbi);
303 		wbi = wbi2;
304 	}
305 }
306 
r5c_handle_cached_data_endio(struct r5conf * conf,struct stripe_head * sh,int disks)307 void r5c_handle_cached_data_endio(struct r5conf *conf,
308 				  struct stripe_head *sh, int disks)
309 {
310 	int i;
311 
312 	for (i = sh->disks; i--; ) {
313 		if (sh->dev[i].written) {
314 			set_bit(R5_UPTODATE, &sh->dev[i].flags);
315 			r5c_return_dev_pending_writes(conf, &sh->dev[i]);
316 			md_bitmap_endwrite(conf->mddev->bitmap, sh->sector,
317 					   RAID5_STRIPE_SECTORS(conf),
318 					   !test_bit(STRIPE_DEGRADED, &sh->state),
319 					   0);
320 		}
321 	}
322 }
323 
324 void r5l_wake_reclaim(struct r5l_log *log, sector_t space);
325 
326 /* Check whether we should flush some stripes to free up stripe cache */
r5c_check_stripe_cache_usage(struct r5conf * conf)327 void r5c_check_stripe_cache_usage(struct r5conf *conf)
328 {
329 	int total_cached;
330 
331 	if (!r5c_is_writeback(conf->log))
332 		return;
333 
334 	total_cached = atomic_read(&conf->r5c_cached_partial_stripes) +
335 		atomic_read(&conf->r5c_cached_full_stripes);
336 
337 	/*
338 	 * The following condition is true for either of the following:
339 	 *   - stripe cache pressure high:
340 	 *          total_cached > 3/4 min_nr_stripes ||
341 	 *          empty_inactive_list_nr > 0
342 	 *   - stripe cache pressure moderate:
343 	 *          total_cached > 1/2 min_nr_stripes
344 	 */
345 	if (total_cached > conf->min_nr_stripes * 1 / 2 ||
346 	    atomic_read(&conf->empty_inactive_list_nr) > 0)
347 		r5l_wake_reclaim(conf->log, 0);
348 }
349 
350 /*
351  * flush cache when there are R5C_FULL_STRIPE_FLUSH_BATCH or more full
352  * stripes in the cache
353  */
r5c_check_cached_full_stripe(struct r5conf * conf)354 void r5c_check_cached_full_stripe(struct r5conf *conf)
355 {
356 	if (!r5c_is_writeback(conf->log))
357 		return;
358 
359 	/*
360 	 * wake up reclaim for R5C_FULL_STRIPE_FLUSH_BATCH cached stripes
361 	 * or a full stripe (chunk size / 4k stripes).
362 	 */
363 	if (atomic_read(&conf->r5c_cached_full_stripes) >=
364 	    min(R5C_FULL_STRIPE_FLUSH_BATCH(conf),
365 		conf->chunk_sectors >> RAID5_STRIPE_SHIFT(conf)))
366 		r5l_wake_reclaim(conf->log, 0);
367 }
368 
369 /*
370  * Total log space (in sectors) needed to flush all data in cache
371  *
372  * To avoid deadlock due to log space, it is necessary to reserve log
373  * space to flush critical stripes (stripes that occupying log space near
374  * last_checkpoint). This function helps check how much log space is
375  * required to flush all cached stripes.
376  *
377  * To reduce log space requirements, two mechanisms are used to give cache
378  * flush higher priorities:
379  *    1. In handle_stripe_dirtying() and schedule_reconstruction(),
380  *       stripes ALREADY in journal can be flushed w/o pending writes;
381  *    2. In r5l_write_stripe() and r5c_cache_data(), stripes NOT in journal
382  *       can be delayed (r5l_add_no_space_stripe).
383  *
384  * In cache flush, the stripe goes through 1 and then 2. For a stripe that
385  * already passed 1, flushing it requires at most (conf->max_degraded + 1)
386  * pages of journal space. For stripes that has not passed 1, flushing it
387  * requires (conf->raid_disks + 1) pages of journal space. There are at
388  * most (conf->group_cnt + 1) stripe that passed 1. So total journal space
389  * required to flush all cached stripes (in pages) is:
390  *
391  *     (stripe_in_journal_count - group_cnt - 1) * (max_degraded + 1) +
392  *     (group_cnt + 1) * (raid_disks + 1)
393  * or
394  *     (stripe_in_journal_count) * (max_degraded + 1) +
395  *     (group_cnt + 1) * (raid_disks - max_degraded)
396  */
r5c_log_required_to_flush_cache(struct r5conf * conf)397 static sector_t r5c_log_required_to_flush_cache(struct r5conf *conf)
398 {
399 	struct r5l_log *log = conf->log;
400 
401 	if (!r5c_is_writeback(log))
402 		return 0;
403 
404 	return BLOCK_SECTORS *
405 		((conf->max_degraded + 1) * atomic_read(&log->stripe_in_journal_count) +
406 		 (conf->raid_disks - conf->max_degraded) * (conf->group_cnt + 1));
407 }
408 
409 /*
410  * evaluate log space usage and update R5C_LOG_TIGHT and R5C_LOG_CRITICAL
411  *
412  * R5C_LOG_TIGHT is set when free space on the log device is less than 3x of
413  * reclaim_required_space. R5C_LOG_CRITICAL is set when free space on the log
414  * device is less than 2x of reclaim_required_space.
415  */
r5c_update_log_state(struct r5l_log * log)416 static inline void r5c_update_log_state(struct r5l_log *log)
417 {
418 	struct r5conf *conf = log->rdev->mddev->private;
419 	sector_t free_space;
420 	sector_t reclaim_space;
421 	bool wake_reclaim = false;
422 
423 	if (!r5c_is_writeback(log))
424 		return;
425 
426 	free_space = r5l_ring_distance(log, log->log_start,
427 				       log->last_checkpoint);
428 	reclaim_space = r5c_log_required_to_flush_cache(conf);
429 	if (free_space < 2 * reclaim_space)
430 		set_bit(R5C_LOG_CRITICAL, &conf->cache_state);
431 	else {
432 		if (test_bit(R5C_LOG_CRITICAL, &conf->cache_state))
433 			wake_reclaim = true;
434 		clear_bit(R5C_LOG_CRITICAL, &conf->cache_state);
435 	}
436 	if (free_space < 3 * reclaim_space)
437 		set_bit(R5C_LOG_TIGHT, &conf->cache_state);
438 	else
439 		clear_bit(R5C_LOG_TIGHT, &conf->cache_state);
440 
441 	if (wake_reclaim)
442 		r5l_wake_reclaim(log, 0);
443 }
444 
445 /*
446  * Put the stripe into writing-out phase by clearing STRIPE_R5C_CACHING.
447  * This function should only be called in write-back mode.
448  */
r5c_make_stripe_write_out(struct stripe_head * sh)449 void r5c_make_stripe_write_out(struct stripe_head *sh)
450 {
451 	struct r5conf *conf = sh->raid_conf;
452 	struct r5l_log *log = conf->log;
453 
454 	BUG_ON(!r5c_is_writeback(log));
455 
456 	WARN_ON(!test_bit(STRIPE_R5C_CACHING, &sh->state));
457 	clear_bit(STRIPE_R5C_CACHING, &sh->state);
458 
459 	if (!test_and_set_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
460 		atomic_inc(&conf->preread_active_stripes);
461 }
462 
r5c_handle_data_cached(struct stripe_head * sh)463 static void r5c_handle_data_cached(struct stripe_head *sh)
464 {
465 	int i;
466 
467 	for (i = sh->disks; i--; )
468 		if (test_and_clear_bit(R5_Wantwrite, &sh->dev[i].flags)) {
469 			set_bit(R5_InJournal, &sh->dev[i].flags);
470 			clear_bit(R5_LOCKED, &sh->dev[i].flags);
471 		}
472 	clear_bit(STRIPE_LOG_TRAPPED, &sh->state);
473 }
474 
475 /*
476  * this journal write must contain full parity,
477  * it may also contain some data pages
478  */
r5c_handle_parity_cached(struct stripe_head * sh)479 static void r5c_handle_parity_cached(struct stripe_head *sh)
480 {
481 	int i;
482 
483 	for (i = sh->disks; i--; )
484 		if (test_bit(R5_InJournal, &sh->dev[i].flags))
485 			set_bit(R5_Wantwrite, &sh->dev[i].flags);
486 }
487 
488 /*
489  * Setting proper flags after writing (or flushing) data and/or parity to the
490  * log device. This is called from r5l_log_endio() or r5l_log_flush_endio().
491  */
r5c_finish_cache_stripe(struct stripe_head * sh)492 static void r5c_finish_cache_stripe(struct stripe_head *sh)
493 {
494 	struct r5l_log *log = sh->raid_conf->log;
495 
496 	if (log->r5c_journal_mode == R5C_JOURNAL_MODE_WRITE_THROUGH) {
497 		BUG_ON(test_bit(STRIPE_R5C_CACHING, &sh->state));
498 		/*
499 		 * Set R5_InJournal for parity dev[pd_idx]. This means
500 		 * all data AND parity in the journal. For RAID 6, it is
501 		 * NOT necessary to set the flag for dev[qd_idx], as the
502 		 * two parities are written out together.
503 		 */
504 		set_bit(R5_InJournal, &sh->dev[sh->pd_idx].flags);
505 	} else if (test_bit(STRIPE_R5C_CACHING, &sh->state)) {
506 		r5c_handle_data_cached(sh);
507 	} else {
508 		r5c_handle_parity_cached(sh);
509 		set_bit(R5_InJournal, &sh->dev[sh->pd_idx].flags);
510 	}
511 }
512 
r5l_io_run_stripes(struct r5l_io_unit * io)513 static void r5l_io_run_stripes(struct r5l_io_unit *io)
514 {
515 	struct stripe_head *sh, *next;
516 
517 	list_for_each_entry_safe(sh, next, &io->stripe_list, log_list) {
518 		list_del_init(&sh->log_list);
519 
520 		r5c_finish_cache_stripe(sh);
521 
522 		set_bit(STRIPE_HANDLE, &sh->state);
523 		raid5_release_stripe(sh);
524 	}
525 }
526 
r5l_log_run_stripes(struct r5l_log * log)527 static void r5l_log_run_stripes(struct r5l_log *log)
528 {
529 	struct r5l_io_unit *io, *next;
530 
531 	lockdep_assert_held(&log->io_list_lock);
532 
533 	list_for_each_entry_safe(io, next, &log->running_ios, log_sibling) {
534 		/* don't change list order */
535 		if (io->state < IO_UNIT_IO_END)
536 			break;
537 
538 		list_move_tail(&io->log_sibling, &log->finished_ios);
539 		r5l_io_run_stripes(io);
540 	}
541 }
542 
r5l_move_to_end_ios(struct r5l_log * log)543 static void r5l_move_to_end_ios(struct r5l_log *log)
544 {
545 	struct r5l_io_unit *io, *next;
546 
547 	lockdep_assert_held(&log->io_list_lock);
548 
549 	list_for_each_entry_safe(io, next, &log->running_ios, log_sibling) {
550 		/* don't change list order */
551 		if (io->state < IO_UNIT_IO_END)
552 			break;
553 		list_move_tail(&io->log_sibling, &log->io_end_ios);
554 	}
555 }
556 
557 static void __r5l_stripe_write_finished(struct r5l_io_unit *io);
r5l_log_endio(struct bio * bio)558 static void r5l_log_endio(struct bio *bio)
559 {
560 	struct r5l_io_unit *io = bio->bi_private;
561 	struct r5l_io_unit *io_deferred;
562 	struct r5l_log *log = io->log;
563 	unsigned long flags;
564 	bool has_null_flush;
565 	bool has_flush_payload;
566 
567 	if (bio->bi_status)
568 		md_error(log->rdev->mddev, log->rdev);
569 
570 	bio_put(bio);
571 	mempool_free(io->meta_page, &log->meta_pool);
572 
573 	spin_lock_irqsave(&log->io_list_lock, flags);
574 	__r5l_set_io_unit_state(io, IO_UNIT_IO_END);
575 
576 	/*
577 	 * if the io doesn't not have null_flush or flush payload,
578 	 * it is not safe to access it after releasing io_list_lock.
579 	 * Therefore, it is necessary to check the condition with
580 	 * the lock held.
581 	 */
582 	has_null_flush = io->has_null_flush;
583 	has_flush_payload = io->has_flush_payload;
584 
585 	if (log->need_cache_flush && !list_empty(&io->stripe_list))
586 		r5l_move_to_end_ios(log);
587 	else
588 		r5l_log_run_stripes(log);
589 	if (!list_empty(&log->running_ios)) {
590 		/*
591 		 * FLUSH/FUA io_unit is deferred because of ordering, now we
592 		 * can dispatch it
593 		 */
594 		io_deferred = list_first_entry(&log->running_ios,
595 					       struct r5l_io_unit, log_sibling);
596 		if (io_deferred->io_deferred)
597 			schedule_work(&log->deferred_io_work);
598 	}
599 
600 	spin_unlock_irqrestore(&log->io_list_lock, flags);
601 
602 	if (log->need_cache_flush)
603 		md_wakeup_thread(log->rdev->mddev->thread);
604 
605 	/* finish flush only io_unit and PAYLOAD_FLUSH only io_unit */
606 	if (has_null_flush) {
607 		struct bio *bi;
608 
609 		WARN_ON(bio_list_empty(&io->flush_barriers));
610 		while ((bi = bio_list_pop(&io->flush_barriers)) != NULL) {
611 			bio_endio(bi);
612 			if (atomic_dec_and_test(&io->pending_stripe)) {
613 				__r5l_stripe_write_finished(io);
614 				return;
615 			}
616 		}
617 	}
618 	/* decrease pending_stripe for flush payload */
619 	if (has_flush_payload)
620 		if (atomic_dec_and_test(&io->pending_stripe))
621 			__r5l_stripe_write_finished(io);
622 }
623 
r5l_do_submit_io(struct r5l_log * log,struct r5l_io_unit * io)624 static void r5l_do_submit_io(struct r5l_log *log, struct r5l_io_unit *io)
625 {
626 	unsigned long flags;
627 
628 	spin_lock_irqsave(&log->io_list_lock, flags);
629 	__r5l_set_io_unit_state(io, IO_UNIT_IO_START);
630 	spin_unlock_irqrestore(&log->io_list_lock, flags);
631 
632 	/*
633 	 * In case of journal device failures, submit_bio will get error
634 	 * and calls endio, then active stripes will continue write
635 	 * process. Therefore, it is not necessary to check Faulty bit
636 	 * of journal device here.
637 	 *
638 	 * We can't check split_bio after current_bio is submitted. If
639 	 * io->split_bio is null, after current_bio is submitted, current_bio
640 	 * might already be completed and the io_unit is freed. We submit
641 	 * split_bio first to avoid the issue.
642 	 */
643 	if (io->split_bio) {
644 		if (io->has_flush)
645 			io->split_bio->bi_opf |= REQ_PREFLUSH;
646 		if (io->has_fua)
647 			io->split_bio->bi_opf |= REQ_FUA;
648 		submit_bio(io->split_bio);
649 	}
650 
651 	if (io->has_flush)
652 		io->current_bio->bi_opf |= REQ_PREFLUSH;
653 	if (io->has_fua)
654 		io->current_bio->bi_opf |= REQ_FUA;
655 	submit_bio(io->current_bio);
656 }
657 
658 /* deferred io_unit will be dispatched here */
r5l_submit_io_async(struct work_struct * work)659 static void r5l_submit_io_async(struct work_struct *work)
660 {
661 	struct r5l_log *log = container_of(work, struct r5l_log,
662 					   deferred_io_work);
663 	struct r5l_io_unit *io = NULL;
664 	unsigned long flags;
665 
666 	spin_lock_irqsave(&log->io_list_lock, flags);
667 	if (!list_empty(&log->running_ios)) {
668 		io = list_first_entry(&log->running_ios, struct r5l_io_unit,
669 				      log_sibling);
670 		if (!io->io_deferred)
671 			io = NULL;
672 		else
673 			io->io_deferred = 0;
674 	}
675 	spin_unlock_irqrestore(&log->io_list_lock, flags);
676 	if (io)
677 		r5l_do_submit_io(log, io);
678 }
679 
r5c_disable_writeback_async(struct work_struct * work)680 static void r5c_disable_writeback_async(struct work_struct *work)
681 {
682 	struct r5l_log *log = container_of(work, struct r5l_log,
683 					   disable_writeback_work);
684 	struct mddev *mddev = log->rdev->mddev;
685 	struct r5conf *conf = mddev->private;
686 	int locked = 0;
687 
688 	if (log->r5c_journal_mode == R5C_JOURNAL_MODE_WRITE_THROUGH)
689 		return;
690 	pr_info("md/raid:%s: Disabling writeback cache for degraded array.\n",
691 		mdname(mddev));
692 
693 	/* wait superblock change before suspend */
694 	wait_event(mddev->sb_wait,
695 		   conf->log == NULL ||
696 		   (!test_bit(MD_SB_CHANGE_PENDING, &mddev->sb_flags) &&
697 		    (locked = mddev_trylock(mddev))));
698 	if (locked) {
699 		mddev_suspend(mddev);
700 		log->r5c_journal_mode = R5C_JOURNAL_MODE_WRITE_THROUGH;
701 		mddev_resume(mddev);
702 		mddev_unlock(mddev);
703 	}
704 }
705 
r5l_submit_current_io(struct r5l_log * log)706 static void r5l_submit_current_io(struct r5l_log *log)
707 {
708 	struct r5l_io_unit *io = log->current_io;
709 	struct r5l_meta_block *block;
710 	unsigned long flags;
711 	u32 crc;
712 	bool do_submit = true;
713 
714 	if (!io)
715 		return;
716 
717 	block = page_address(io->meta_page);
718 	block->meta_size = cpu_to_le32(io->meta_offset);
719 	crc = crc32c_le(log->uuid_checksum, block, PAGE_SIZE);
720 	block->checksum = cpu_to_le32(crc);
721 
722 	log->current_io = NULL;
723 	spin_lock_irqsave(&log->io_list_lock, flags);
724 	if (io->has_flush || io->has_fua) {
725 		if (io != list_first_entry(&log->running_ios,
726 					   struct r5l_io_unit, log_sibling)) {
727 			io->io_deferred = 1;
728 			do_submit = false;
729 		}
730 	}
731 	spin_unlock_irqrestore(&log->io_list_lock, flags);
732 	if (do_submit)
733 		r5l_do_submit_io(log, io);
734 }
735 
r5l_bio_alloc(struct r5l_log * log)736 static struct bio *r5l_bio_alloc(struct r5l_log *log)
737 {
738 	struct bio *bio = bio_alloc_bioset(log->rdev->bdev, BIO_MAX_VECS,
739 					   REQ_OP_WRITE, GFP_NOIO, &log->bs);
740 
741 	bio->bi_iter.bi_sector = log->rdev->data_offset + log->log_start;
742 
743 	return bio;
744 }
745 
r5_reserve_log_entry(struct r5l_log * log,struct r5l_io_unit * io)746 static void r5_reserve_log_entry(struct r5l_log *log, struct r5l_io_unit *io)
747 {
748 	log->log_start = r5l_ring_add(log, log->log_start, BLOCK_SECTORS);
749 
750 	r5c_update_log_state(log);
751 	/*
752 	 * If we filled up the log device start from the beginning again,
753 	 * which will require a new bio.
754 	 *
755 	 * Note: for this to work properly the log size needs to me a multiple
756 	 * of BLOCK_SECTORS.
757 	 */
758 	if (log->log_start == 0)
759 		io->need_split_bio = true;
760 
761 	io->log_end = log->log_start;
762 }
763 
r5l_new_meta(struct r5l_log * log)764 static struct r5l_io_unit *r5l_new_meta(struct r5l_log *log)
765 {
766 	struct r5l_io_unit *io;
767 	struct r5l_meta_block *block;
768 
769 	io = mempool_alloc(&log->io_pool, GFP_ATOMIC);
770 	if (!io)
771 		return NULL;
772 	memset(io, 0, sizeof(*io));
773 
774 	io->log = log;
775 	INIT_LIST_HEAD(&io->log_sibling);
776 	INIT_LIST_HEAD(&io->stripe_list);
777 	bio_list_init(&io->flush_barriers);
778 	io->state = IO_UNIT_RUNNING;
779 
780 	io->meta_page = mempool_alloc(&log->meta_pool, GFP_NOIO);
781 	block = page_address(io->meta_page);
782 	clear_page(block);
783 	block->magic = cpu_to_le32(R5LOG_MAGIC);
784 	block->version = R5LOG_VERSION;
785 	block->seq = cpu_to_le64(log->seq);
786 	block->position = cpu_to_le64(log->log_start);
787 
788 	io->log_start = log->log_start;
789 	io->meta_offset = sizeof(struct r5l_meta_block);
790 	io->seq = log->seq++;
791 
792 	io->current_bio = r5l_bio_alloc(log);
793 	io->current_bio->bi_end_io = r5l_log_endio;
794 	io->current_bio->bi_private = io;
795 	__bio_add_page(io->current_bio, io->meta_page, PAGE_SIZE, 0);
796 
797 	r5_reserve_log_entry(log, io);
798 
799 	spin_lock_irq(&log->io_list_lock);
800 	list_add_tail(&io->log_sibling, &log->running_ios);
801 	spin_unlock_irq(&log->io_list_lock);
802 
803 	return io;
804 }
805 
r5l_get_meta(struct r5l_log * log,unsigned int payload_size)806 static int r5l_get_meta(struct r5l_log *log, unsigned int payload_size)
807 {
808 	if (log->current_io &&
809 	    log->current_io->meta_offset + payload_size > PAGE_SIZE)
810 		r5l_submit_current_io(log);
811 
812 	if (!log->current_io) {
813 		log->current_io = r5l_new_meta(log);
814 		if (!log->current_io)
815 			return -ENOMEM;
816 	}
817 
818 	return 0;
819 }
820 
r5l_append_payload_meta(struct r5l_log * log,u16 type,sector_t location,u32 checksum1,u32 checksum2,bool checksum2_valid)821 static void r5l_append_payload_meta(struct r5l_log *log, u16 type,
822 				    sector_t location,
823 				    u32 checksum1, u32 checksum2,
824 				    bool checksum2_valid)
825 {
826 	struct r5l_io_unit *io = log->current_io;
827 	struct r5l_payload_data_parity *payload;
828 
829 	payload = page_address(io->meta_page) + io->meta_offset;
830 	payload->header.type = cpu_to_le16(type);
831 	payload->header.flags = cpu_to_le16(0);
832 	payload->size = cpu_to_le32((1 + !!checksum2_valid) <<
833 				    (PAGE_SHIFT - 9));
834 	payload->location = cpu_to_le64(location);
835 	payload->checksum[0] = cpu_to_le32(checksum1);
836 	if (checksum2_valid)
837 		payload->checksum[1] = cpu_to_le32(checksum2);
838 
839 	io->meta_offset += sizeof(struct r5l_payload_data_parity) +
840 		sizeof(__le32) * (1 + !!checksum2_valid);
841 }
842 
r5l_append_payload_page(struct r5l_log * log,struct page * page)843 static void r5l_append_payload_page(struct r5l_log *log, struct page *page)
844 {
845 	struct r5l_io_unit *io = log->current_io;
846 
847 	if (io->need_split_bio) {
848 		BUG_ON(io->split_bio);
849 		io->split_bio = io->current_bio;
850 		io->current_bio = r5l_bio_alloc(log);
851 		bio_chain(io->current_bio, io->split_bio);
852 		io->need_split_bio = false;
853 	}
854 
855 	if (!bio_add_page(io->current_bio, page, PAGE_SIZE, 0))
856 		BUG();
857 
858 	r5_reserve_log_entry(log, io);
859 }
860 
r5l_append_flush_payload(struct r5l_log * log,sector_t sect)861 static void r5l_append_flush_payload(struct r5l_log *log, sector_t sect)
862 {
863 	struct mddev *mddev = log->rdev->mddev;
864 	struct r5conf *conf = mddev->private;
865 	struct r5l_io_unit *io;
866 	struct r5l_payload_flush *payload;
867 	int meta_size;
868 
869 	/*
870 	 * payload_flush requires extra writes to the journal.
871 	 * To avoid handling the extra IO in quiesce, just skip
872 	 * flush_payload
873 	 */
874 	if (conf->quiesce)
875 		return;
876 
877 	mutex_lock(&log->io_mutex);
878 	meta_size = sizeof(struct r5l_payload_flush) + sizeof(__le64);
879 
880 	if (r5l_get_meta(log, meta_size)) {
881 		mutex_unlock(&log->io_mutex);
882 		return;
883 	}
884 
885 	/* current implementation is one stripe per flush payload */
886 	io = log->current_io;
887 	payload = page_address(io->meta_page) + io->meta_offset;
888 	payload->header.type = cpu_to_le16(R5LOG_PAYLOAD_FLUSH);
889 	payload->header.flags = cpu_to_le16(0);
890 	payload->size = cpu_to_le32(sizeof(__le64));
891 	payload->flush_stripes[0] = cpu_to_le64(sect);
892 	io->meta_offset += meta_size;
893 	/* multiple flush payloads count as one pending_stripe */
894 	if (!io->has_flush_payload) {
895 		io->has_flush_payload = 1;
896 		atomic_inc(&io->pending_stripe);
897 	}
898 	mutex_unlock(&log->io_mutex);
899 }
900 
r5l_log_stripe(struct r5l_log * log,struct stripe_head * sh,int data_pages,int parity_pages)901 static int r5l_log_stripe(struct r5l_log *log, struct stripe_head *sh,
902 			   int data_pages, int parity_pages)
903 {
904 	int i;
905 	int meta_size;
906 	int ret;
907 	struct r5l_io_unit *io;
908 
909 	meta_size =
910 		((sizeof(struct r5l_payload_data_parity) + sizeof(__le32))
911 		 * data_pages) +
912 		sizeof(struct r5l_payload_data_parity) +
913 		sizeof(__le32) * parity_pages;
914 
915 	ret = r5l_get_meta(log, meta_size);
916 	if (ret)
917 		return ret;
918 
919 	io = log->current_io;
920 
921 	if (test_and_clear_bit(STRIPE_R5C_PREFLUSH, &sh->state))
922 		io->has_flush = 1;
923 
924 	for (i = 0; i < sh->disks; i++) {
925 		if (!test_bit(R5_Wantwrite, &sh->dev[i].flags) ||
926 		    test_bit(R5_InJournal, &sh->dev[i].flags))
927 			continue;
928 		if (i == sh->pd_idx || i == sh->qd_idx)
929 			continue;
930 		if (test_bit(R5_WantFUA, &sh->dev[i].flags) &&
931 		    log->r5c_journal_mode == R5C_JOURNAL_MODE_WRITE_BACK) {
932 			io->has_fua = 1;
933 			/*
934 			 * we need to flush journal to make sure recovery can
935 			 * reach the data with fua flag
936 			 */
937 			io->has_flush = 1;
938 		}
939 		r5l_append_payload_meta(log, R5LOG_PAYLOAD_DATA,
940 					raid5_compute_blocknr(sh, i, 0),
941 					sh->dev[i].log_checksum, 0, false);
942 		r5l_append_payload_page(log, sh->dev[i].page);
943 	}
944 
945 	if (parity_pages == 2) {
946 		r5l_append_payload_meta(log, R5LOG_PAYLOAD_PARITY,
947 					sh->sector, sh->dev[sh->pd_idx].log_checksum,
948 					sh->dev[sh->qd_idx].log_checksum, true);
949 		r5l_append_payload_page(log, sh->dev[sh->pd_idx].page);
950 		r5l_append_payload_page(log, sh->dev[sh->qd_idx].page);
951 	} else if (parity_pages == 1) {
952 		r5l_append_payload_meta(log, R5LOG_PAYLOAD_PARITY,
953 					sh->sector, sh->dev[sh->pd_idx].log_checksum,
954 					0, false);
955 		r5l_append_payload_page(log, sh->dev[sh->pd_idx].page);
956 	} else  /* Just writing data, not parity, in caching phase */
957 		BUG_ON(parity_pages != 0);
958 
959 	list_add_tail(&sh->log_list, &io->stripe_list);
960 	atomic_inc(&io->pending_stripe);
961 	sh->log_io = io;
962 
963 	if (log->r5c_journal_mode == R5C_JOURNAL_MODE_WRITE_THROUGH)
964 		return 0;
965 
966 	if (sh->log_start == MaxSector) {
967 		BUG_ON(!list_empty(&sh->r5c));
968 		sh->log_start = io->log_start;
969 		spin_lock_irq(&log->stripe_in_journal_lock);
970 		list_add_tail(&sh->r5c,
971 			      &log->stripe_in_journal_list);
972 		spin_unlock_irq(&log->stripe_in_journal_lock);
973 		atomic_inc(&log->stripe_in_journal_count);
974 	}
975 	return 0;
976 }
977 
978 /* add stripe to no_space_stripes, and then wake up reclaim */
r5l_add_no_space_stripe(struct r5l_log * log,struct stripe_head * sh)979 static inline void r5l_add_no_space_stripe(struct r5l_log *log,
980 					   struct stripe_head *sh)
981 {
982 	spin_lock(&log->no_space_stripes_lock);
983 	list_add_tail(&sh->log_list, &log->no_space_stripes);
984 	spin_unlock(&log->no_space_stripes_lock);
985 }
986 
987 /*
988  * running in raid5d, where reclaim could wait for raid5d too (when it flushes
989  * data from log to raid disks), so we shouldn't wait for reclaim here
990  */
r5l_write_stripe(struct r5l_log * log,struct stripe_head * sh)991 int r5l_write_stripe(struct r5l_log *log, struct stripe_head *sh)
992 {
993 	struct r5conf *conf = sh->raid_conf;
994 	int write_disks = 0;
995 	int data_pages, parity_pages;
996 	int reserve;
997 	int i;
998 	int ret = 0;
999 	bool wake_reclaim = false;
1000 
1001 	if (!log)
1002 		return -EAGAIN;
1003 	/* Don't support stripe batch */
1004 	if (sh->log_io || !test_bit(R5_Wantwrite, &sh->dev[sh->pd_idx].flags) ||
1005 	    test_bit(STRIPE_SYNCING, &sh->state)) {
1006 		/* the stripe is written to log, we start writing it to raid */
1007 		clear_bit(STRIPE_LOG_TRAPPED, &sh->state);
1008 		return -EAGAIN;
1009 	}
1010 
1011 	WARN_ON(test_bit(STRIPE_R5C_CACHING, &sh->state));
1012 
1013 	for (i = 0; i < sh->disks; i++) {
1014 		void *addr;
1015 
1016 		if (!test_bit(R5_Wantwrite, &sh->dev[i].flags) ||
1017 		    test_bit(R5_InJournal, &sh->dev[i].flags))
1018 			continue;
1019 
1020 		write_disks++;
1021 		/* checksum is already calculated in last run */
1022 		if (test_bit(STRIPE_LOG_TRAPPED, &sh->state))
1023 			continue;
1024 		addr = kmap_atomic(sh->dev[i].page);
1025 		sh->dev[i].log_checksum = crc32c_le(log->uuid_checksum,
1026 						    addr, PAGE_SIZE);
1027 		kunmap_atomic(addr);
1028 	}
1029 	parity_pages = 1 + !!(sh->qd_idx >= 0);
1030 	data_pages = write_disks - parity_pages;
1031 
1032 	set_bit(STRIPE_LOG_TRAPPED, &sh->state);
1033 	/*
1034 	 * The stripe must enter state machine again to finish the write, so
1035 	 * don't delay.
1036 	 */
1037 	clear_bit(STRIPE_DELAYED, &sh->state);
1038 	atomic_inc(&sh->count);
1039 
1040 	mutex_lock(&log->io_mutex);
1041 	/* meta + data */
1042 	reserve = (1 + write_disks) << (PAGE_SHIFT - 9);
1043 
1044 	if (log->r5c_journal_mode == R5C_JOURNAL_MODE_WRITE_THROUGH) {
1045 		if (!r5l_has_free_space(log, reserve)) {
1046 			r5l_add_no_space_stripe(log, sh);
1047 			wake_reclaim = true;
1048 		} else {
1049 			ret = r5l_log_stripe(log, sh, data_pages, parity_pages);
1050 			if (ret) {
1051 				spin_lock_irq(&log->io_list_lock);
1052 				list_add_tail(&sh->log_list,
1053 					      &log->no_mem_stripes);
1054 				spin_unlock_irq(&log->io_list_lock);
1055 			}
1056 		}
1057 	} else {  /* R5C_JOURNAL_MODE_WRITE_BACK */
1058 		/*
1059 		 * log space critical, do not process stripes that are
1060 		 * not in cache yet (sh->log_start == MaxSector).
1061 		 */
1062 		if (test_bit(R5C_LOG_CRITICAL, &conf->cache_state) &&
1063 		    sh->log_start == MaxSector) {
1064 			r5l_add_no_space_stripe(log, sh);
1065 			wake_reclaim = true;
1066 			reserve = 0;
1067 		} else if (!r5l_has_free_space(log, reserve)) {
1068 			if (sh->log_start == log->last_checkpoint)
1069 				BUG();
1070 			else
1071 				r5l_add_no_space_stripe(log, sh);
1072 		} else {
1073 			ret = r5l_log_stripe(log, sh, data_pages, parity_pages);
1074 			if (ret) {
1075 				spin_lock_irq(&log->io_list_lock);
1076 				list_add_tail(&sh->log_list,
1077 					      &log->no_mem_stripes);
1078 				spin_unlock_irq(&log->io_list_lock);
1079 			}
1080 		}
1081 	}
1082 
1083 	mutex_unlock(&log->io_mutex);
1084 	if (wake_reclaim)
1085 		r5l_wake_reclaim(log, reserve);
1086 	return 0;
1087 }
1088 
r5l_write_stripe_run(struct r5l_log * log)1089 void r5l_write_stripe_run(struct r5l_log *log)
1090 {
1091 	if (!log)
1092 		return;
1093 	mutex_lock(&log->io_mutex);
1094 	r5l_submit_current_io(log);
1095 	mutex_unlock(&log->io_mutex);
1096 }
1097 
r5l_handle_flush_request(struct r5l_log * log,struct bio * bio)1098 int r5l_handle_flush_request(struct r5l_log *log, struct bio *bio)
1099 {
1100 	if (log->r5c_journal_mode == R5C_JOURNAL_MODE_WRITE_THROUGH) {
1101 		/*
1102 		 * in write through (journal only)
1103 		 * we flush log disk cache first, then write stripe data to
1104 		 * raid disks. So if bio is finished, the log disk cache is
1105 		 * flushed already. The recovery guarantees we can recovery
1106 		 * the bio from log disk, so we don't need to flush again
1107 		 */
1108 		if (bio->bi_iter.bi_size == 0) {
1109 			bio_endio(bio);
1110 			return 0;
1111 		}
1112 		bio->bi_opf &= ~REQ_PREFLUSH;
1113 	} else {
1114 		/* write back (with cache) */
1115 		if (bio->bi_iter.bi_size == 0) {
1116 			mutex_lock(&log->io_mutex);
1117 			r5l_get_meta(log, 0);
1118 			bio_list_add(&log->current_io->flush_barriers, bio);
1119 			log->current_io->has_flush = 1;
1120 			log->current_io->has_null_flush = 1;
1121 			atomic_inc(&log->current_io->pending_stripe);
1122 			r5l_submit_current_io(log);
1123 			mutex_unlock(&log->io_mutex);
1124 			return 0;
1125 		}
1126 	}
1127 	return -EAGAIN;
1128 }
1129 
1130 /* This will run after log space is reclaimed */
r5l_run_no_space_stripes(struct r5l_log * log)1131 static void r5l_run_no_space_stripes(struct r5l_log *log)
1132 {
1133 	struct stripe_head *sh;
1134 
1135 	spin_lock(&log->no_space_stripes_lock);
1136 	while (!list_empty(&log->no_space_stripes)) {
1137 		sh = list_first_entry(&log->no_space_stripes,
1138 				      struct stripe_head, log_list);
1139 		list_del_init(&sh->log_list);
1140 		set_bit(STRIPE_HANDLE, &sh->state);
1141 		raid5_release_stripe(sh);
1142 	}
1143 	spin_unlock(&log->no_space_stripes_lock);
1144 }
1145 
1146 /*
1147  * calculate new last_checkpoint
1148  * for write through mode, returns log->next_checkpoint
1149  * for write back, returns log_start of first sh in stripe_in_journal_list
1150  */
r5c_calculate_new_cp(struct r5conf * conf)1151 static sector_t r5c_calculate_new_cp(struct r5conf *conf)
1152 {
1153 	struct stripe_head *sh;
1154 	struct r5l_log *log = conf->log;
1155 	sector_t new_cp;
1156 	unsigned long flags;
1157 
1158 	if (log->r5c_journal_mode == R5C_JOURNAL_MODE_WRITE_THROUGH)
1159 		return log->next_checkpoint;
1160 
1161 	spin_lock_irqsave(&log->stripe_in_journal_lock, flags);
1162 	if (list_empty(&conf->log->stripe_in_journal_list)) {
1163 		/* all stripes flushed */
1164 		spin_unlock_irqrestore(&log->stripe_in_journal_lock, flags);
1165 		return log->next_checkpoint;
1166 	}
1167 	sh = list_first_entry(&conf->log->stripe_in_journal_list,
1168 			      struct stripe_head, r5c);
1169 	new_cp = sh->log_start;
1170 	spin_unlock_irqrestore(&log->stripe_in_journal_lock, flags);
1171 	return new_cp;
1172 }
1173 
r5l_reclaimable_space(struct r5l_log * log)1174 static sector_t r5l_reclaimable_space(struct r5l_log *log)
1175 {
1176 	struct r5conf *conf = log->rdev->mddev->private;
1177 
1178 	return r5l_ring_distance(log, log->last_checkpoint,
1179 				 r5c_calculate_new_cp(conf));
1180 }
1181 
r5l_run_no_mem_stripe(struct r5l_log * log)1182 static void r5l_run_no_mem_stripe(struct r5l_log *log)
1183 {
1184 	struct stripe_head *sh;
1185 
1186 	lockdep_assert_held(&log->io_list_lock);
1187 
1188 	if (!list_empty(&log->no_mem_stripes)) {
1189 		sh = list_first_entry(&log->no_mem_stripes,
1190 				      struct stripe_head, log_list);
1191 		list_del_init(&sh->log_list);
1192 		set_bit(STRIPE_HANDLE, &sh->state);
1193 		raid5_release_stripe(sh);
1194 	}
1195 }
1196 
r5l_complete_finished_ios(struct r5l_log * log)1197 static bool r5l_complete_finished_ios(struct r5l_log *log)
1198 {
1199 	struct r5l_io_unit *io, *next;
1200 	bool found = false;
1201 
1202 	lockdep_assert_held(&log->io_list_lock);
1203 
1204 	list_for_each_entry_safe(io, next, &log->finished_ios, log_sibling) {
1205 		/* don't change list order */
1206 		if (io->state < IO_UNIT_STRIPE_END)
1207 			break;
1208 
1209 		log->next_checkpoint = io->log_start;
1210 
1211 		list_del(&io->log_sibling);
1212 		mempool_free(io, &log->io_pool);
1213 		r5l_run_no_mem_stripe(log);
1214 
1215 		found = true;
1216 	}
1217 
1218 	return found;
1219 }
1220 
__r5l_stripe_write_finished(struct r5l_io_unit * io)1221 static void __r5l_stripe_write_finished(struct r5l_io_unit *io)
1222 {
1223 	struct r5l_log *log = io->log;
1224 	struct r5conf *conf = log->rdev->mddev->private;
1225 	unsigned long flags;
1226 
1227 	spin_lock_irqsave(&log->io_list_lock, flags);
1228 	__r5l_set_io_unit_state(io, IO_UNIT_STRIPE_END);
1229 
1230 	if (!r5l_complete_finished_ios(log)) {
1231 		spin_unlock_irqrestore(&log->io_list_lock, flags);
1232 		return;
1233 	}
1234 
1235 	if (r5l_reclaimable_space(log) > log->max_free_space ||
1236 	    test_bit(R5C_LOG_TIGHT, &conf->cache_state))
1237 		r5l_wake_reclaim(log, 0);
1238 
1239 	spin_unlock_irqrestore(&log->io_list_lock, flags);
1240 	wake_up(&log->iounit_wait);
1241 }
1242 
r5l_stripe_write_finished(struct stripe_head * sh)1243 void r5l_stripe_write_finished(struct stripe_head *sh)
1244 {
1245 	struct r5l_io_unit *io;
1246 
1247 	io = sh->log_io;
1248 	sh->log_io = NULL;
1249 
1250 	if (io && atomic_dec_and_test(&io->pending_stripe))
1251 		__r5l_stripe_write_finished(io);
1252 }
1253 
r5l_log_flush_endio(struct bio * bio)1254 static void r5l_log_flush_endio(struct bio *bio)
1255 {
1256 	struct r5l_log *log = container_of(bio, struct r5l_log,
1257 		flush_bio);
1258 	unsigned long flags;
1259 	struct r5l_io_unit *io;
1260 
1261 	if (bio->bi_status)
1262 		md_error(log->rdev->mddev, log->rdev);
1263 	bio_uninit(bio);
1264 
1265 	spin_lock_irqsave(&log->io_list_lock, flags);
1266 	list_for_each_entry(io, &log->flushing_ios, log_sibling)
1267 		r5l_io_run_stripes(io);
1268 	list_splice_tail_init(&log->flushing_ios, &log->finished_ios);
1269 	spin_unlock_irqrestore(&log->io_list_lock, flags);
1270 }
1271 
1272 /*
1273  * Starting dispatch IO to raid.
1274  * io_unit(meta) consists of a log. There is one situation we want to avoid. A
1275  * broken meta in the middle of a log causes recovery can't find meta at the
1276  * head of log. If operations require meta at the head persistent in log, we
1277  * must make sure meta before it persistent in log too. A case is:
1278  *
1279  * stripe data/parity is in log, we start write stripe to raid disks. stripe
1280  * data/parity must be persistent in log before we do the write to raid disks.
1281  *
1282  * The solution is we restrictly maintain io_unit list order. In this case, we
1283  * only write stripes of an io_unit to raid disks till the io_unit is the first
1284  * one whose data/parity is in log.
1285  */
r5l_flush_stripe_to_raid(struct r5l_log * log)1286 void r5l_flush_stripe_to_raid(struct r5l_log *log)
1287 {
1288 	bool do_flush;
1289 
1290 	if (!log || !log->need_cache_flush)
1291 		return;
1292 
1293 	spin_lock_irq(&log->io_list_lock);
1294 	/* flush bio is running */
1295 	if (!list_empty(&log->flushing_ios)) {
1296 		spin_unlock_irq(&log->io_list_lock);
1297 		return;
1298 	}
1299 	list_splice_tail_init(&log->io_end_ios, &log->flushing_ios);
1300 	do_flush = !list_empty(&log->flushing_ios);
1301 	spin_unlock_irq(&log->io_list_lock);
1302 
1303 	if (!do_flush)
1304 		return;
1305 	bio_init(&log->flush_bio, log->rdev->bdev, NULL, 0,
1306 		  REQ_OP_WRITE | REQ_PREFLUSH);
1307 	log->flush_bio.bi_end_io = r5l_log_flush_endio;
1308 	submit_bio(&log->flush_bio);
1309 }
1310 
1311 static void r5l_write_super(struct r5l_log *log, sector_t cp);
r5l_write_super_and_discard_space(struct r5l_log * log,sector_t end)1312 static void r5l_write_super_and_discard_space(struct r5l_log *log,
1313 	sector_t end)
1314 {
1315 	struct block_device *bdev = log->rdev->bdev;
1316 	struct mddev *mddev;
1317 
1318 	r5l_write_super(log, end);
1319 
1320 	if (!bdev_max_discard_sectors(bdev))
1321 		return;
1322 
1323 	mddev = log->rdev->mddev;
1324 	/*
1325 	 * Discard could zero data, so before discard we must make sure
1326 	 * superblock is updated to new log tail. Updating superblock (either
1327 	 * directly call md_update_sb() or depend on md thread) must hold
1328 	 * reconfig mutex. On the other hand, raid5_quiesce is called with
1329 	 * reconfig_mutex hold. The first step of raid5_quiesce() is waiting
1330 	 * for all IO finish, hence waiting for reclaim thread, while reclaim
1331 	 * thread is calling this function and waiting for reconfig mutex. So
1332 	 * there is a deadlock. We workaround this issue with a trylock.
1333 	 * FIXME: we could miss discard if we can't take reconfig mutex
1334 	 */
1335 	set_mask_bits(&mddev->sb_flags, 0,
1336 		BIT(MD_SB_CHANGE_DEVS) | BIT(MD_SB_CHANGE_PENDING));
1337 	if (!mddev_trylock(mddev))
1338 		return;
1339 	md_update_sb(mddev, 1);
1340 	mddev_unlock(mddev);
1341 
1342 	/* discard IO error really doesn't matter, ignore it */
1343 	if (log->last_checkpoint < end) {
1344 		blkdev_issue_discard(bdev,
1345 				log->last_checkpoint + log->rdev->data_offset,
1346 				end - log->last_checkpoint, GFP_NOIO);
1347 	} else {
1348 		blkdev_issue_discard(bdev,
1349 				log->last_checkpoint + log->rdev->data_offset,
1350 				log->device_size - log->last_checkpoint,
1351 				GFP_NOIO);
1352 		blkdev_issue_discard(bdev, log->rdev->data_offset, end,
1353 				GFP_NOIO);
1354 	}
1355 }
1356 
1357 /*
1358  * r5c_flush_stripe moves stripe from cached list to handle_list. When called,
1359  * the stripe must be on r5c_cached_full_stripes or r5c_cached_partial_stripes.
1360  *
1361  * must hold conf->device_lock
1362  */
r5c_flush_stripe(struct r5conf * conf,struct stripe_head * sh)1363 static void r5c_flush_stripe(struct r5conf *conf, struct stripe_head *sh)
1364 {
1365 	BUG_ON(list_empty(&sh->lru));
1366 	BUG_ON(!test_bit(STRIPE_R5C_CACHING, &sh->state));
1367 	BUG_ON(test_bit(STRIPE_HANDLE, &sh->state));
1368 
1369 	/*
1370 	 * The stripe is not ON_RELEASE_LIST, so it is safe to call
1371 	 * raid5_release_stripe() while holding conf->device_lock
1372 	 */
1373 	BUG_ON(test_bit(STRIPE_ON_RELEASE_LIST, &sh->state));
1374 	lockdep_assert_held(&conf->device_lock);
1375 
1376 	list_del_init(&sh->lru);
1377 	atomic_inc(&sh->count);
1378 
1379 	set_bit(STRIPE_HANDLE, &sh->state);
1380 	atomic_inc(&conf->active_stripes);
1381 	r5c_make_stripe_write_out(sh);
1382 
1383 	if (test_bit(STRIPE_R5C_PARTIAL_STRIPE, &sh->state))
1384 		atomic_inc(&conf->r5c_flushing_partial_stripes);
1385 	else
1386 		atomic_inc(&conf->r5c_flushing_full_stripes);
1387 	raid5_release_stripe(sh);
1388 }
1389 
1390 /*
1391  * if num == 0, flush all full stripes
1392  * if num > 0, flush all full stripes. If less than num full stripes are
1393  *             flushed, flush some partial stripes until totally num stripes are
1394  *             flushed or there is no more cached stripes.
1395  */
r5c_flush_cache(struct r5conf * conf,int num)1396 void r5c_flush_cache(struct r5conf *conf, int num)
1397 {
1398 	int count;
1399 	struct stripe_head *sh, *next;
1400 
1401 	lockdep_assert_held(&conf->device_lock);
1402 	if (!conf->log)
1403 		return;
1404 
1405 	count = 0;
1406 	list_for_each_entry_safe(sh, next, &conf->r5c_full_stripe_list, lru) {
1407 		r5c_flush_stripe(conf, sh);
1408 		count++;
1409 	}
1410 
1411 	if (count >= num)
1412 		return;
1413 	list_for_each_entry_safe(sh, next,
1414 				 &conf->r5c_partial_stripe_list, lru) {
1415 		r5c_flush_stripe(conf, sh);
1416 		if (++count >= num)
1417 			break;
1418 	}
1419 }
1420 
r5c_do_reclaim(struct r5conf * conf)1421 static void r5c_do_reclaim(struct r5conf *conf)
1422 {
1423 	struct r5l_log *log = conf->log;
1424 	struct stripe_head *sh;
1425 	int count = 0;
1426 	unsigned long flags;
1427 	int total_cached;
1428 	int stripes_to_flush;
1429 	int flushing_partial, flushing_full;
1430 
1431 	if (!r5c_is_writeback(log))
1432 		return;
1433 
1434 	flushing_partial = atomic_read(&conf->r5c_flushing_partial_stripes);
1435 	flushing_full = atomic_read(&conf->r5c_flushing_full_stripes);
1436 	total_cached = atomic_read(&conf->r5c_cached_partial_stripes) +
1437 		atomic_read(&conf->r5c_cached_full_stripes) -
1438 		flushing_full - flushing_partial;
1439 
1440 	if (total_cached > conf->min_nr_stripes * 3 / 4 ||
1441 	    atomic_read(&conf->empty_inactive_list_nr) > 0)
1442 		/*
1443 		 * if stripe cache pressure high, flush all full stripes and
1444 		 * some partial stripes
1445 		 */
1446 		stripes_to_flush = R5C_RECLAIM_STRIPE_GROUP;
1447 	else if (total_cached > conf->min_nr_stripes * 1 / 2 ||
1448 		 atomic_read(&conf->r5c_cached_full_stripes) - flushing_full >
1449 		 R5C_FULL_STRIPE_FLUSH_BATCH(conf))
1450 		/*
1451 		 * if stripe cache pressure moderate, or if there is many full
1452 		 * stripes,flush all full stripes
1453 		 */
1454 		stripes_to_flush = 0;
1455 	else
1456 		/* no need to flush */
1457 		stripes_to_flush = -1;
1458 
1459 	if (stripes_to_flush >= 0) {
1460 		spin_lock_irqsave(&conf->device_lock, flags);
1461 		r5c_flush_cache(conf, stripes_to_flush);
1462 		spin_unlock_irqrestore(&conf->device_lock, flags);
1463 	}
1464 
1465 	/* if log space is tight, flush stripes on stripe_in_journal_list */
1466 	if (test_bit(R5C_LOG_TIGHT, &conf->cache_state)) {
1467 		spin_lock_irqsave(&log->stripe_in_journal_lock, flags);
1468 		spin_lock(&conf->device_lock);
1469 		list_for_each_entry(sh, &log->stripe_in_journal_list, r5c) {
1470 			/*
1471 			 * stripes on stripe_in_journal_list could be in any
1472 			 * state of the stripe_cache state machine. In this
1473 			 * case, we only want to flush stripe on
1474 			 * r5c_cached_full/partial_stripes. The following
1475 			 * condition makes sure the stripe is on one of the
1476 			 * two lists.
1477 			 */
1478 			if (!list_empty(&sh->lru) &&
1479 			    !test_bit(STRIPE_HANDLE, &sh->state) &&
1480 			    atomic_read(&sh->count) == 0) {
1481 				r5c_flush_stripe(conf, sh);
1482 				if (count++ >= R5C_RECLAIM_STRIPE_GROUP)
1483 					break;
1484 			}
1485 		}
1486 		spin_unlock(&conf->device_lock);
1487 		spin_unlock_irqrestore(&log->stripe_in_journal_lock, flags);
1488 	}
1489 
1490 	if (!test_bit(R5C_LOG_CRITICAL, &conf->cache_state))
1491 		r5l_run_no_space_stripes(log);
1492 
1493 	md_wakeup_thread(conf->mddev->thread);
1494 }
1495 
r5l_do_reclaim(struct r5l_log * log)1496 static void r5l_do_reclaim(struct r5l_log *log)
1497 {
1498 	struct r5conf *conf = log->rdev->mddev->private;
1499 	sector_t reclaim_target = xchg(&log->reclaim_target, 0);
1500 	sector_t reclaimable;
1501 	sector_t next_checkpoint;
1502 	bool write_super;
1503 
1504 	spin_lock_irq(&log->io_list_lock);
1505 	write_super = r5l_reclaimable_space(log) > log->max_free_space ||
1506 		reclaim_target != 0 || !list_empty(&log->no_space_stripes);
1507 	/*
1508 	 * move proper io_unit to reclaim list. We should not change the order.
1509 	 * reclaimable/unreclaimable io_unit can be mixed in the list, we
1510 	 * shouldn't reuse space of an unreclaimable io_unit
1511 	 */
1512 	while (1) {
1513 		reclaimable = r5l_reclaimable_space(log);
1514 		if (reclaimable >= reclaim_target ||
1515 		    (list_empty(&log->running_ios) &&
1516 		     list_empty(&log->io_end_ios) &&
1517 		     list_empty(&log->flushing_ios) &&
1518 		     list_empty(&log->finished_ios)))
1519 			break;
1520 
1521 		md_wakeup_thread(log->rdev->mddev->thread);
1522 		wait_event_lock_irq(log->iounit_wait,
1523 				    r5l_reclaimable_space(log) > reclaimable,
1524 				    log->io_list_lock);
1525 	}
1526 
1527 	next_checkpoint = r5c_calculate_new_cp(conf);
1528 	spin_unlock_irq(&log->io_list_lock);
1529 
1530 	if (reclaimable == 0 || !write_super)
1531 		return;
1532 
1533 	/*
1534 	 * write_super will flush cache of each raid disk. We must write super
1535 	 * here, because the log area might be reused soon and we don't want to
1536 	 * confuse recovery
1537 	 */
1538 	r5l_write_super_and_discard_space(log, next_checkpoint);
1539 
1540 	mutex_lock(&log->io_mutex);
1541 	log->last_checkpoint = next_checkpoint;
1542 	r5c_update_log_state(log);
1543 	mutex_unlock(&log->io_mutex);
1544 
1545 	r5l_run_no_space_stripes(log);
1546 }
1547 
r5l_reclaim_thread(struct md_thread * thread)1548 static void r5l_reclaim_thread(struct md_thread *thread)
1549 {
1550 	struct mddev *mddev = thread->mddev;
1551 	struct r5conf *conf = mddev->private;
1552 	struct r5l_log *log = conf->log;
1553 
1554 	if (!log)
1555 		return;
1556 	r5c_do_reclaim(conf);
1557 	r5l_do_reclaim(log);
1558 }
1559 
r5l_wake_reclaim(struct r5l_log * log,sector_t space)1560 void r5l_wake_reclaim(struct r5l_log *log, sector_t space)
1561 {
1562 	unsigned long target;
1563 	unsigned long new = (unsigned long)space; /* overflow in theory */
1564 
1565 	if (!log)
1566 		return;
1567 
1568 	target = READ_ONCE(log->reclaim_target);
1569 	do {
1570 		if (new < target)
1571 			return;
1572 	} while (!try_cmpxchg(&log->reclaim_target, &target, new));
1573 	md_wakeup_thread(log->reclaim_thread);
1574 }
1575 
r5l_quiesce(struct r5l_log * log,int quiesce)1576 void r5l_quiesce(struct r5l_log *log, int quiesce)
1577 {
1578 	struct mddev *mddev = log->rdev->mddev;
1579 	struct md_thread *thread = rcu_dereference_protected(
1580 		log->reclaim_thread, lockdep_is_held(&mddev->reconfig_mutex));
1581 
1582 	if (quiesce) {
1583 		/* make sure r5l_write_super_and_discard_space exits */
1584 		wake_up(&mddev->sb_wait);
1585 		kthread_park(thread->tsk);
1586 		r5l_wake_reclaim(log, MaxSector);
1587 		r5l_do_reclaim(log);
1588 	} else
1589 		kthread_unpark(thread->tsk);
1590 }
1591 
r5l_log_disk_error(struct r5conf * conf)1592 bool r5l_log_disk_error(struct r5conf *conf)
1593 {
1594 	struct r5l_log *log = conf->log;
1595 
1596 	/* don't allow write if journal disk is missing */
1597 	if (!log)
1598 		return test_bit(MD_HAS_JOURNAL, &conf->mddev->flags);
1599 	else
1600 		return test_bit(Faulty, &log->rdev->flags);
1601 }
1602 
1603 #define R5L_RECOVERY_PAGE_POOL_SIZE 256
1604 
1605 struct r5l_recovery_ctx {
1606 	struct page *meta_page;		/* current meta */
1607 	sector_t meta_total_blocks;	/* total size of current meta and data */
1608 	sector_t pos;			/* recovery position */
1609 	u64 seq;			/* recovery position seq */
1610 	int data_parity_stripes;	/* number of data_parity stripes */
1611 	int data_only_stripes;		/* number of data_only stripes */
1612 	struct list_head cached_list;
1613 
1614 	/*
1615 	 * read ahead page pool (ra_pool)
1616 	 * in recovery, log is read sequentially. It is not efficient to
1617 	 * read every page with sync_page_io(). The read ahead page pool
1618 	 * reads multiple pages with one IO, so further log read can
1619 	 * just copy data from the pool.
1620 	 */
1621 	struct page *ra_pool[R5L_RECOVERY_PAGE_POOL_SIZE];
1622 	struct bio_vec ra_bvec[R5L_RECOVERY_PAGE_POOL_SIZE];
1623 	sector_t pool_offset;	/* offset of first page in the pool */
1624 	int total_pages;	/* total allocated pages */
1625 	int valid_pages;	/* pages with valid data */
1626 };
1627 
r5l_recovery_allocate_ra_pool(struct r5l_log * log,struct r5l_recovery_ctx * ctx)1628 static int r5l_recovery_allocate_ra_pool(struct r5l_log *log,
1629 					    struct r5l_recovery_ctx *ctx)
1630 {
1631 	struct page *page;
1632 
1633 	ctx->valid_pages = 0;
1634 	ctx->total_pages = 0;
1635 	while (ctx->total_pages < R5L_RECOVERY_PAGE_POOL_SIZE) {
1636 		page = alloc_page(GFP_KERNEL);
1637 
1638 		if (!page)
1639 			break;
1640 		ctx->ra_pool[ctx->total_pages] = page;
1641 		ctx->total_pages += 1;
1642 	}
1643 
1644 	if (ctx->total_pages == 0)
1645 		return -ENOMEM;
1646 
1647 	ctx->pool_offset = 0;
1648 	return 0;
1649 }
1650 
r5l_recovery_free_ra_pool(struct r5l_log * log,struct r5l_recovery_ctx * ctx)1651 static void r5l_recovery_free_ra_pool(struct r5l_log *log,
1652 					struct r5l_recovery_ctx *ctx)
1653 {
1654 	int i;
1655 
1656 	for (i = 0; i < ctx->total_pages; ++i)
1657 		put_page(ctx->ra_pool[i]);
1658 }
1659 
1660 /*
1661  * fetch ctx->valid_pages pages from offset
1662  * In normal cases, ctx->valid_pages == ctx->total_pages after the call.
1663  * However, if the offset is close to the end of the journal device,
1664  * ctx->valid_pages could be smaller than ctx->total_pages
1665  */
r5l_recovery_fetch_ra_pool(struct r5l_log * log,struct r5l_recovery_ctx * ctx,sector_t offset)1666 static int r5l_recovery_fetch_ra_pool(struct r5l_log *log,
1667 				      struct r5l_recovery_ctx *ctx,
1668 				      sector_t offset)
1669 {
1670 	struct bio bio;
1671 	int ret;
1672 
1673 	bio_init(&bio, log->rdev->bdev, ctx->ra_bvec,
1674 		 R5L_RECOVERY_PAGE_POOL_SIZE, REQ_OP_READ);
1675 	bio.bi_iter.bi_sector = log->rdev->data_offset + offset;
1676 
1677 	ctx->valid_pages = 0;
1678 	ctx->pool_offset = offset;
1679 
1680 	while (ctx->valid_pages < ctx->total_pages) {
1681 		__bio_add_page(&bio, ctx->ra_pool[ctx->valid_pages], PAGE_SIZE,
1682 			       0);
1683 		ctx->valid_pages += 1;
1684 
1685 		offset = r5l_ring_add(log, offset, BLOCK_SECTORS);
1686 
1687 		if (offset == 0)  /* reached end of the device */
1688 			break;
1689 	}
1690 
1691 	ret = submit_bio_wait(&bio);
1692 	bio_uninit(&bio);
1693 	return ret;
1694 }
1695 
1696 /*
1697  * try read a page from the read ahead page pool, if the page is not in the
1698  * pool, call r5l_recovery_fetch_ra_pool
1699  */
r5l_recovery_read_page(struct r5l_log * log,struct r5l_recovery_ctx * ctx,struct page * page,sector_t offset)1700 static int r5l_recovery_read_page(struct r5l_log *log,
1701 				  struct r5l_recovery_ctx *ctx,
1702 				  struct page *page,
1703 				  sector_t offset)
1704 {
1705 	int ret;
1706 
1707 	if (offset < ctx->pool_offset ||
1708 	    offset >= ctx->pool_offset + ctx->valid_pages * BLOCK_SECTORS) {
1709 		ret = r5l_recovery_fetch_ra_pool(log, ctx, offset);
1710 		if (ret)
1711 			return ret;
1712 	}
1713 
1714 	BUG_ON(offset < ctx->pool_offset ||
1715 	       offset >= ctx->pool_offset + ctx->valid_pages * BLOCK_SECTORS);
1716 
1717 	memcpy(page_address(page),
1718 	       page_address(ctx->ra_pool[(offset - ctx->pool_offset) >>
1719 					 BLOCK_SECTOR_SHIFT]),
1720 	       PAGE_SIZE);
1721 	return 0;
1722 }
1723 
r5l_recovery_read_meta_block(struct r5l_log * log,struct r5l_recovery_ctx * ctx)1724 static int r5l_recovery_read_meta_block(struct r5l_log *log,
1725 					struct r5l_recovery_ctx *ctx)
1726 {
1727 	struct page *page = ctx->meta_page;
1728 	struct r5l_meta_block *mb;
1729 	u32 crc, stored_crc;
1730 	int ret;
1731 
1732 	ret = r5l_recovery_read_page(log, ctx, page, ctx->pos);
1733 	if (ret != 0)
1734 		return ret;
1735 
1736 	mb = page_address(page);
1737 	stored_crc = le32_to_cpu(mb->checksum);
1738 	mb->checksum = 0;
1739 
1740 	if (le32_to_cpu(mb->magic) != R5LOG_MAGIC ||
1741 	    le64_to_cpu(mb->seq) != ctx->seq ||
1742 	    mb->version != R5LOG_VERSION ||
1743 	    le64_to_cpu(mb->position) != ctx->pos)
1744 		return -EINVAL;
1745 
1746 	crc = crc32c_le(log->uuid_checksum, mb, PAGE_SIZE);
1747 	if (stored_crc != crc)
1748 		return -EINVAL;
1749 
1750 	if (le32_to_cpu(mb->meta_size) > PAGE_SIZE)
1751 		return -EINVAL;
1752 
1753 	ctx->meta_total_blocks = BLOCK_SECTORS;
1754 
1755 	return 0;
1756 }
1757 
1758 static void
r5l_recovery_create_empty_meta_block(struct r5l_log * log,struct page * page,sector_t pos,u64 seq)1759 r5l_recovery_create_empty_meta_block(struct r5l_log *log,
1760 				     struct page *page,
1761 				     sector_t pos, u64 seq)
1762 {
1763 	struct r5l_meta_block *mb;
1764 
1765 	mb = page_address(page);
1766 	clear_page(mb);
1767 	mb->magic = cpu_to_le32(R5LOG_MAGIC);
1768 	mb->version = R5LOG_VERSION;
1769 	mb->meta_size = cpu_to_le32(sizeof(struct r5l_meta_block));
1770 	mb->seq = cpu_to_le64(seq);
1771 	mb->position = cpu_to_le64(pos);
1772 }
1773 
r5l_log_write_empty_meta_block(struct r5l_log * log,sector_t pos,u64 seq)1774 static int r5l_log_write_empty_meta_block(struct r5l_log *log, sector_t pos,
1775 					  u64 seq)
1776 {
1777 	struct page *page;
1778 	struct r5l_meta_block *mb;
1779 
1780 	page = alloc_page(GFP_KERNEL);
1781 	if (!page)
1782 		return -ENOMEM;
1783 	r5l_recovery_create_empty_meta_block(log, page, pos, seq);
1784 	mb = page_address(page);
1785 	mb->checksum = cpu_to_le32(crc32c_le(log->uuid_checksum,
1786 					     mb, PAGE_SIZE));
1787 	if (!sync_page_io(log->rdev, pos, PAGE_SIZE, page, REQ_OP_WRITE |
1788 			  REQ_SYNC | REQ_FUA, false)) {
1789 		__free_page(page);
1790 		return -EIO;
1791 	}
1792 	__free_page(page);
1793 	return 0;
1794 }
1795 
1796 /*
1797  * r5l_recovery_load_data and r5l_recovery_load_parity uses flag R5_Wantwrite
1798  * to mark valid (potentially not flushed) data in the journal.
1799  *
1800  * We already verified checksum in r5l_recovery_verify_data_checksum_for_mb,
1801  * so there should not be any mismatch here.
1802  */
r5l_recovery_load_data(struct r5l_log * log,struct stripe_head * sh,struct r5l_recovery_ctx * ctx,struct r5l_payload_data_parity * payload,sector_t log_offset)1803 static void r5l_recovery_load_data(struct r5l_log *log,
1804 				   struct stripe_head *sh,
1805 				   struct r5l_recovery_ctx *ctx,
1806 				   struct r5l_payload_data_parity *payload,
1807 				   sector_t log_offset)
1808 {
1809 	struct mddev *mddev = log->rdev->mddev;
1810 	struct r5conf *conf = mddev->private;
1811 	int dd_idx;
1812 
1813 	raid5_compute_sector(conf,
1814 			     le64_to_cpu(payload->location), 0,
1815 			     &dd_idx, sh);
1816 	r5l_recovery_read_page(log, ctx, sh->dev[dd_idx].page, log_offset);
1817 	sh->dev[dd_idx].log_checksum =
1818 		le32_to_cpu(payload->checksum[0]);
1819 	ctx->meta_total_blocks += BLOCK_SECTORS;
1820 
1821 	set_bit(R5_Wantwrite, &sh->dev[dd_idx].flags);
1822 	set_bit(STRIPE_R5C_CACHING, &sh->state);
1823 }
1824 
r5l_recovery_load_parity(struct r5l_log * log,struct stripe_head * sh,struct r5l_recovery_ctx * ctx,struct r5l_payload_data_parity * payload,sector_t log_offset)1825 static void r5l_recovery_load_parity(struct r5l_log *log,
1826 				     struct stripe_head *sh,
1827 				     struct r5l_recovery_ctx *ctx,
1828 				     struct r5l_payload_data_parity *payload,
1829 				     sector_t log_offset)
1830 {
1831 	struct mddev *mddev = log->rdev->mddev;
1832 	struct r5conf *conf = mddev->private;
1833 
1834 	ctx->meta_total_blocks += BLOCK_SECTORS * conf->max_degraded;
1835 	r5l_recovery_read_page(log, ctx, sh->dev[sh->pd_idx].page, log_offset);
1836 	sh->dev[sh->pd_idx].log_checksum =
1837 		le32_to_cpu(payload->checksum[0]);
1838 	set_bit(R5_Wantwrite, &sh->dev[sh->pd_idx].flags);
1839 
1840 	if (sh->qd_idx >= 0) {
1841 		r5l_recovery_read_page(
1842 			log, ctx, sh->dev[sh->qd_idx].page,
1843 			r5l_ring_add(log, log_offset, BLOCK_SECTORS));
1844 		sh->dev[sh->qd_idx].log_checksum =
1845 			le32_to_cpu(payload->checksum[1]);
1846 		set_bit(R5_Wantwrite, &sh->dev[sh->qd_idx].flags);
1847 	}
1848 	clear_bit(STRIPE_R5C_CACHING, &sh->state);
1849 }
1850 
r5l_recovery_reset_stripe(struct stripe_head * sh)1851 static void r5l_recovery_reset_stripe(struct stripe_head *sh)
1852 {
1853 	int i;
1854 
1855 	sh->state = 0;
1856 	sh->log_start = MaxSector;
1857 	for (i = sh->disks; i--; )
1858 		sh->dev[i].flags = 0;
1859 }
1860 
1861 static void
r5l_recovery_replay_one_stripe(struct r5conf * conf,struct stripe_head * sh,struct r5l_recovery_ctx * ctx)1862 r5l_recovery_replay_one_stripe(struct r5conf *conf,
1863 			       struct stripe_head *sh,
1864 			       struct r5l_recovery_ctx *ctx)
1865 {
1866 	struct md_rdev *rdev, *rrdev;
1867 	int disk_index;
1868 	int data_count = 0;
1869 
1870 	for (disk_index = 0; disk_index < sh->disks; disk_index++) {
1871 		if (!test_bit(R5_Wantwrite, &sh->dev[disk_index].flags))
1872 			continue;
1873 		if (disk_index == sh->qd_idx || disk_index == sh->pd_idx)
1874 			continue;
1875 		data_count++;
1876 	}
1877 
1878 	/*
1879 	 * stripes that only have parity must have been flushed
1880 	 * before the crash that we are now recovering from, so
1881 	 * there is nothing more to recovery.
1882 	 */
1883 	if (data_count == 0)
1884 		goto out;
1885 
1886 	for (disk_index = 0; disk_index < sh->disks; disk_index++) {
1887 		if (!test_bit(R5_Wantwrite, &sh->dev[disk_index].flags))
1888 			continue;
1889 
1890 		/* in case device is broken */
1891 		rcu_read_lock();
1892 		rdev = rcu_dereference(conf->disks[disk_index].rdev);
1893 		if (rdev) {
1894 			atomic_inc(&rdev->nr_pending);
1895 			rcu_read_unlock();
1896 			sync_page_io(rdev, sh->sector, PAGE_SIZE,
1897 				     sh->dev[disk_index].page, REQ_OP_WRITE,
1898 				     false);
1899 			rdev_dec_pending(rdev, rdev->mddev);
1900 			rcu_read_lock();
1901 		}
1902 		rrdev = rcu_dereference(conf->disks[disk_index].replacement);
1903 		if (rrdev) {
1904 			atomic_inc(&rrdev->nr_pending);
1905 			rcu_read_unlock();
1906 			sync_page_io(rrdev, sh->sector, PAGE_SIZE,
1907 				     sh->dev[disk_index].page, REQ_OP_WRITE,
1908 				     false);
1909 			rdev_dec_pending(rrdev, rrdev->mddev);
1910 			rcu_read_lock();
1911 		}
1912 		rcu_read_unlock();
1913 	}
1914 	ctx->data_parity_stripes++;
1915 out:
1916 	r5l_recovery_reset_stripe(sh);
1917 }
1918 
1919 static struct stripe_head *
r5c_recovery_alloc_stripe(struct r5conf * conf,sector_t stripe_sect,int noblock)1920 r5c_recovery_alloc_stripe(
1921 		struct r5conf *conf,
1922 		sector_t stripe_sect,
1923 		int noblock)
1924 {
1925 	struct stripe_head *sh;
1926 
1927 	sh = raid5_get_active_stripe(conf, NULL, stripe_sect,
1928 				     noblock ? R5_GAS_NOBLOCK : 0);
1929 	if (!sh)
1930 		return NULL;  /* no more stripe available */
1931 
1932 	r5l_recovery_reset_stripe(sh);
1933 
1934 	return sh;
1935 }
1936 
1937 static struct stripe_head *
r5c_recovery_lookup_stripe(struct list_head * list,sector_t sect)1938 r5c_recovery_lookup_stripe(struct list_head *list, sector_t sect)
1939 {
1940 	struct stripe_head *sh;
1941 
1942 	list_for_each_entry(sh, list, lru)
1943 		if (sh->sector == sect)
1944 			return sh;
1945 	return NULL;
1946 }
1947 
1948 static void
r5c_recovery_drop_stripes(struct list_head * cached_stripe_list,struct r5l_recovery_ctx * ctx)1949 r5c_recovery_drop_stripes(struct list_head *cached_stripe_list,
1950 			  struct r5l_recovery_ctx *ctx)
1951 {
1952 	struct stripe_head *sh, *next;
1953 
1954 	list_for_each_entry_safe(sh, next, cached_stripe_list, lru) {
1955 		r5l_recovery_reset_stripe(sh);
1956 		list_del_init(&sh->lru);
1957 		raid5_release_stripe(sh);
1958 	}
1959 }
1960 
1961 static void
r5c_recovery_replay_stripes(struct list_head * cached_stripe_list,struct r5l_recovery_ctx * ctx)1962 r5c_recovery_replay_stripes(struct list_head *cached_stripe_list,
1963 			    struct r5l_recovery_ctx *ctx)
1964 {
1965 	struct stripe_head *sh, *next;
1966 
1967 	list_for_each_entry_safe(sh, next, cached_stripe_list, lru)
1968 		if (!test_bit(STRIPE_R5C_CACHING, &sh->state)) {
1969 			r5l_recovery_replay_one_stripe(sh->raid_conf, sh, ctx);
1970 			list_del_init(&sh->lru);
1971 			raid5_release_stripe(sh);
1972 		}
1973 }
1974 
1975 /* if matches return 0; otherwise return -EINVAL */
1976 static int
r5l_recovery_verify_data_checksum(struct r5l_log * log,struct r5l_recovery_ctx * ctx,struct page * page,sector_t log_offset,__le32 log_checksum)1977 r5l_recovery_verify_data_checksum(struct r5l_log *log,
1978 				  struct r5l_recovery_ctx *ctx,
1979 				  struct page *page,
1980 				  sector_t log_offset, __le32 log_checksum)
1981 {
1982 	void *addr;
1983 	u32 checksum;
1984 
1985 	r5l_recovery_read_page(log, ctx, page, log_offset);
1986 	addr = kmap_atomic(page);
1987 	checksum = crc32c_le(log->uuid_checksum, addr, PAGE_SIZE);
1988 	kunmap_atomic(addr);
1989 	return (le32_to_cpu(log_checksum) == checksum) ? 0 : -EINVAL;
1990 }
1991 
1992 /*
1993  * before loading data to stripe cache, we need verify checksum for all data,
1994  * if there is mismatch for any data page, we drop all data in the mata block
1995  */
1996 static int
r5l_recovery_verify_data_checksum_for_mb(struct r5l_log * log,struct r5l_recovery_ctx * ctx)1997 r5l_recovery_verify_data_checksum_for_mb(struct r5l_log *log,
1998 					 struct r5l_recovery_ctx *ctx)
1999 {
2000 	struct mddev *mddev = log->rdev->mddev;
2001 	struct r5conf *conf = mddev->private;
2002 	struct r5l_meta_block *mb = page_address(ctx->meta_page);
2003 	sector_t mb_offset = sizeof(struct r5l_meta_block);
2004 	sector_t log_offset = r5l_ring_add(log, ctx->pos, BLOCK_SECTORS);
2005 	struct page *page;
2006 	struct r5l_payload_data_parity *payload;
2007 	struct r5l_payload_flush *payload_flush;
2008 
2009 	page = alloc_page(GFP_KERNEL);
2010 	if (!page)
2011 		return -ENOMEM;
2012 
2013 	while (mb_offset < le32_to_cpu(mb->meta_size)) {
2014 		payload = (void *)mb + mb_offset;
2015 		payload_flush = (void *)mb + mb_offset;
2016 
2017 		if (le16_to_cpu(payload->header.type) == R5LOG_PAYLOAD_DATA) {
2018 			if (r5l_recovery_verify_data_checksum(
2019 				    log, ctx, page, log_offset,
2020 				    payload->checksum[0]) < 0)
2021 				goto mismatch;
2022 		} else if (le16_to_cpu(payload->header.type) == R5LOG_PAYLOAD_PARITY) {
2023 			if (r5l_recovery_verify_data_checksum(
2024 				    log, ctx, page, log_offset,
2025 				    payload->checksum[0]) < 0)
2026 				goto mismatch;
2027 			if (conf->max_degraded == 2 && /* q for RAID 6 */
2028 			    r5l_recovery_verify_data_checksum(
2029 				    log, ctx, page,
2030 				    r5l_ring_add(log, log_offset,
2031 						 BLOCK_SECTORS),
2032 				    payload->checksum[1]) < 0)
2033 				goto mismatch;
2034 		} else if (le16_to_cpu(payload->header.type) == R5LOG_PAYLOAD_FLUSH) {
2035 			/* nothing to do for R5LOG_PAYLOAD_FLUSH here */
2036 		} else /* not R5LOG_PAYLOAD_DATA/PARITY/FLUSH */
2037 			goto mismatch;
2038 
2039 		if (le16_to_cpu(payload->header.type) == R5LOG_PAYLOAD_FLUSH) {
2040 			mb_offset += sizeof(struct r5l_payload_flush) +
2041 				le32_to_cpu(payload_flush->size);
2042 		} else {
2043 			/* DATA or PARITY payload */
2044 			log_offset = r5l_ring_add(log, log_offset,
2045 						  le32_to_cpu(payload->size));
2046 			mb_offset += sizeof(struct r5l_payload_data_parity) +
2047 				sizeof(__le32) *
2048 				(le32_to_cpu(payload->size) >> (PAGE_SHIFT - 9));
2049 		}
2050 
2051 	}
2052 
2053 	put_page(page);
2054 	return 0;
2055 
2056 mismatch:
2057 	put_page(page);
2058 	return -EINVAL;
2059 }
2060 
2061 /*
2062  * Analyze all data/parity pages in one meta block
2063  * Returns:
2064  * 0 for success
2065  * -EINVAL for unknown playload type
2066  * -EAGAIN for checksum mismatch of data page
2067  * -ENOMEM for run out of memory (alloc_page failed or run out of stripes)
2068  */
2069 static int
r5c_recovery_analyze_meta_block(struct r5l_log * log,struct r5l_recovery_ctx * ctx,struct list_head * cached_stripe_list)2070 r5c_recovery_analyze_meta_block(struct r5l_log *log,
2071 				struct r5l_recovery_ctx *ctx,
2072 				struct list_head *cached_stripe_list)
2073 {
2074 	struct mddev *mddev = log->rdev->mddev;
2075 	struct r5conf *conf = mddev->private;
2076 	struct r5l_meta_block *mb;
2077 	struct r5l_payload_data_parity *payload;
2078 	struct r5l_payload_flush *payload_flush;
2079 	int mb_offset;
2080 	sector_t log_offset;
2081 	sector_t stripe_sect;
2082 	struct stripe_head *sh;
2083 	int ret;
2084 
2085 	/*
2086 	 * for mismatch in data blocks, we will drop all data in this mb, but
2087 	 * we will still read next mb for other data with FLUSH flag, as
2088 	 * io_unit could finish out of order.
2089 	 */
2090 	ret = r5l_recovery_verify_data_checksum_for_mb(log, ctx);
2091 	if (ret == -EINVAL)
2092 		return -EAGAIN;
2093 	else if (ret)
2094 		return ret;   /* -ENOMEM duo to alloc_page() failed */
2095 
2096 	mb = page_address(ctx->meta_page);
2097 	mb_offset = sizeof(struct r5l_meta_block);
2098 	log_offset = r5l_ring_add(log, ctx->pos, BLOCK_SECTORS);
2099 
2100 	while (mb_offset < le32_to_cpu(mb->meta_size)) {
2101 		int dd;
2102 
2103 		payload = (void *)mb + mb_offset;
2104 		payload_flush = (void *)mb + mb_offset;
2105 
2106 		if (le16_to_cpu(payload->header.type) == R5LOG_PAYLOAD_FLUSH) {
2107 			int i, count;
2108 
2109 			count = le32_to_cpu(payload_flush->size) / sizeof(__le64);
2110 			for (i = 0; i < count; ++i) {
2111 				stripe_sect = le64_to_cpu(payload_flush->flush_stripes[i]);
2112 				sh = r5c_recovery_lookup_stripe(cached_stripe_list,
2113 								stripe_sect);
2114 				if (sh) {
2115 					WARN_ON(test_bit(STRIPE_R5C_CACHING, &sh->state));
2116 					r5l_recovery_reset_stripe(sh);
2117 					list_del_init(&sh->lru);
2118 					raid5_release_stripe(sh);
2119 				}
2120 			}
2121 
2122 			mb_offset += sizeof(struct r5l_payload_flush) +
2123 				le32_to_cpu(payload_flush->size);
2124 			continue;
2125 		}
2126 
2127 		/* DATA or PARITY payload */
2128 		stripe_sect = (le16_to_cpu(payload->header.type) == R5LOG_PAYLOAD_DATA) ?
2129 			raid5_compute_sector(
2130 				conf, le64_to_cpu(payload->location), 0, &dd,
2131 				NULL)
2132 			: le64_to_cpu(payload->location);
2133 
2134 		sh = r5c_recovery_lookup_stripe(cached_stripe_list,
2135 						stripe_sect);
2136 
2137 		if (!sh) {
2138 			sh = r5c_recovery_alloc_stripe(conf, stripe_sect, 1);
2139 			/*
2140 			 * cannot get stripe from raid5_get_active_stripe
2141 			 * try replay some stripes
2142 			 */
2143 			if (!sh) {
2144 				r5c_recovery_replay_stripes(
2145 					cached_stripe_list, ctx);
2146 				sh = r5c_recovery_alloc_stripe(
2147 					conf, stripe_sect, 1);
2148 			}
2149 			if (!sh) {
2150 				int new_size = conf->min_nr_stripes * 2;
2151 				pr_debug("md/raid:%s: Increasing stripe cache size to %d to recovery data on journal.\n",
2152 					mdname(mddev),
2153 					new_size);
2154 				ret = raid5_set_cache_size(mddev, new_size);
2155 				if (conf->min_nr_stripes <= new_size / 2) {
2156 					pr_err("md/raid:%s: Cannot increase cache size, ret=%d, new_size=%d, min_nr_stripes=%d, max_nr_stripes=%d\n",
2157 						mdname(mddev),
2158 						ret,
2159 						new_size,
2160 						conf->min_nr_stripes,
2161 						conf->max_nr_stripes);
2162 					return -ENOMEM;
2163 				}
2164 				sh = r5c_recovery_alloc_stripe(
2165 					conf, stripe_sect, 0);
2166 			}
2167 			if (!sh) {
2168 				pr_err("md/raid:%s: Cannot get enough stripes due to memory pressure. Recovery failed.\n",
2169 					mdname(mddev));
2170 				return -ENOMEM;
2171 			}
2172 			list_add_tail(&sh->lru, cached_stripe_list);
2173 		}
2174 
2175 		if (le16_to_cpu(payload->header.type) == R5LOG_PAYLOAD_DATA) {
2176 			if (!test_bit(STRIPE_R5C_CACHING, &sh->state) &&
2177 			    test_bit(R5_Wantwrite, &sh->dev[sh->pd_idx].flags)) {
2178 				r5l_recovery_replay_one_stripe(conf, sh, ctx);
2179 				list_move_tail(&sh->lru, cached_stripe_list);
2180 			}
2181 			r5l_recovery_load_data(log, sh, ctx, payload,
2182 					       log_offset);
2183 		} else if (le16_to_cpu(payload->header.type) == R5LOG_PAYLOAD_PARITY)
2184 			r5l_recovery_load_parity(log, sh, ctx, payload,
2185 						 log_offset);
2186 		else
2187 			return -EINVAL;
2188 
2189 		log_offset = r5l_ring_add(log, log_offset,
2190 					  le32_to_cpu(payload->size));
2191 
2192 		mb_offset += sizeof(struct r5l_payload_data_parity) +
2193 			sizeof(__le32) *
2194 			(le32_to_cpu(payload->size) >> (PAGE_SHIFT - 9));
2195 	}
2196 
2197 	return 0;
2198 }
2199 
2200 /*
2201  * Load the stripe into cache. The stripe will be written out later by
2202  * the stripe cache state machine.
2203  */
r5c_recovery_load_one_stripe(struct r5l_log * log,struct stripe_head * sh)2204 static void r5c_recovery_load_one_stripe(struct r5l_log *log,
2205 					 struct stripe_head *sh)
2206 {
2207 	struct r5dev *dev;
2208 	int i;
2209 
2210 	for (i = sh->disks; i--; ) {
2211 		dev = sh->dev + i;
2212 		if (test_and_clear_bit(R5_Wantwrite, &dev->flags)) {
2213 			set_bit(R5_InJournal, &dev->flags);
2214 			set_bit(R5_UPTODATE, &dev->flags);
2215 		}
2216 	}
2217 }
2218 
2219 /*
2220  * Scan through the log for all to-be-flushed data
2221  *
2222  * For stripes with data and parity, namely Data-Parity stripe
2223  * (STRIPE_R5C_CACHING == 0), we simply replay all the writes.
2224  *
2225  * For stripes with only data, namely Data-Only stripe
2226  * (STRIPE_R5C_CACHING == 1), we load them to stripe cache state machine.
2227  *
2228  * For a stripe, if we see data after parity, we should discard all previous
2229  * data and parity for this stripe, as these data are already flushed to
2230  * the array.
2231  *
2232  * At the end of the scan, we return the new journal_tail, which points to
2233  * first data-only stripe on the journal device, or next invalid meta block.
2234  */
r5c_recovery_flush_log(struct r5l_log * log,struct r5l_recovery_ctx * ctx)2235 static int r5c_recovery_flush_log(struct r5l_log *log,
2236 				  struct r5l_recovery_ctx *ctx)
2237 {
2238 	struct stripe_head *sh;
2239 	int ret = 0;
2240 
2241 	/* scan through the log */
2242 	while (1) {
2243 		if (r5l_recovery_read_meta_block(log, ctx))
2244 			break;
2245 
2246 		ret = r5c_recovery_analyze_meta_block(log, ctx,
2247 						      &ctx->cached_list);
2248 		/*
2249 		 * -EAGAIN means mismatch in data block, in this case, we still
2250 		 * try scan the next metablock
2251 		 */
2252 		if (ret && ret != -EAGAIN)
2253 			break;   /* ret == -EINVAL or -ENOMEM */
2254 		ctx->seq++;
2255 		ctx->pos = r5l_ring_add(log, ctx->pos, ctx->meta_total_blocks);
2256 	}
2257 
2258 	if (ret == -ENOMEM) {
2259 		r5c_recovery_drop_stripes(&ctx->cached_list, ctx);
2260 		return ret;
2261 	}
2262 
2263 	/* replay data-parity stripes */
2264 	r5c_recovery_replay_stripes(&ctx->cached_list, ctx);
2265 
2266 	/* load data-only stripes to stripe cache */
2267 	list_for_each_entry(sh, &ctx->cached_list, lru) {
2268 		WARN_ON(!test_bit(STRIPE_R5C_CACHING, &sh->state));
2269 		r5c_recovery_load_one_stripe(log, sh);
2270 		ctx->data_only_stripes++;
2271 	}
2272 
2273 	return 0;
2274 }
2275 
2276 /*
2277  * we did a recovery. Now ctx.pos points to an invalid meta block. New
2278  * log will start here. but we can't let superblock point to last valid
2279  * meta block. The log might looks like:
2280  * | meta 1| meta 2| meta 3|
2281  * meta 1 is valid, meta 2 is invalid. meta 3 could be valid. If
2282  * superblock points to meta 1, we write a new valid meta 2n.  if crash
2283  * happens again, new recovery will start from meta 1. Since meta 2n is
2284  * valid now, recovery will think meta 3 is valid, which is wrong.
2285  * The solution is we create a new meta in meta2 with its seq == meta
2286  * 1's seq + 10000 and let superblock points to meta2. The same recovery
2287  * will not think meta 3 is a valid meta, because its seq doesn't match
2288  */
2289 
2290 /*
2291  * Before recovery, the log looks like the following
2292  *
2293  *   ---------------------------------------------
2294  *   |           valid log        | invalid log  |
2295  *   ---------------------------------------------
2296  *   ^
2297  *   |- log->last_checkpoint
2298  *   |- log->last_cp_seq
2299  *
2300  * Now we scan through the log until we see invalid entry
2301  *
2302  *   ---------------------------------------------
2303  *   |           valid log        | invalid log  |
2304  *   ---------------------------------------------
2305  *   ^                            ^
2306  *   |- log->last_checkpoint      |- ctx->pos
2307  *   |- log->last_cp_seq          |- ctx->seq
2308  *
2309  * From this point, we need to increase seq number by 10 to avoid
2310  * confusing next recovery.
2311  *
2312  *   ---------------------------------------------
2313  *   |           valid log        | invalid log  |
2314  *   ---------------------------------------------
2315  *   ^                              ^
2316  *   |- log->last_checkpoint        |- ctx->pos+1
2317  *   |- log->last_cp_seq            |- ctx->seq+10001
2318  *
2319  * However, it is not safe to start the state machine yet, because data only
2320  * parities are not yet secured in RAID. To save these data only parities, we
2321  * rewrite them from seq+11.
2322  *
2323  *   -----------------------------------------------------------------
2324  *   |           valid log        | data only stripes | invalid log  |
2325  *   -----------------------------------------------------------------
2326  *   ^                                                ^
2327  *   |- log->last_checkpoint                          |- ctx->pos+n
2328  *   |- log->last_cp_seq                              |- ctx->seq+10000+n
2329  *
2330  * If failure happens again during this process, the recovery can safe start
2331  * again from log->last_checkpoint.
2332  *
2333  * Once data only stripes are rewritten to journal, we move log_tail
2334  *
2335  *   -----------------------------------------------------------------
2336  *   |     old log        |    data only stripes    | invalid log  |
2337  *   -----------------------------------------------------------------
2338  *                        ^                         ^
2339  *                        |- log->last_checkpoint   |- ctx->pos+n
2340  *                        |- log->last_cp_seq       |- ctx->seq+10000+n
2341  *
2342  * Then we can safely start the state machine. If failure happens from this
2343  * point on, the recovery will start from new log->last_checkpoint.
2344  */
2345 static int
r5c_recovery_rewrite_data_only_stripes(struct r5l_log * log,struct r5l_recovery_ctx * ctx)2346 r5c_recovery_rewrite_data_only_stripes(struct r5l_log *log,
2347 				       struct r5l_recovery_ctx *ctx)
2348 {
2349 	struct stripe_head *sh;
2350 	struct mddev *mddev = log->rdev->mddev;
2351 	struct page *page;
2352 	sector_t next_checkpoint = MaxSector;
2353 
2354 	page = alloc_page(GFP_KERNEL);
2355 	if (!page) {
2356 		pr_err("md/raid:%s: cannot allocate memory to rewrite data only stripes\n",
2357 		       mdname(mddev));
2358 		return -ENOMEM;
2359 	}
2360 
2361 	WARN_ON(list_empty(&ctx->cached_list));
2362 
2363 	list_for_each_entry(sh, &ctx->cached_list, lru) {
2364 		struct r5l_meta_block *mb;
2365 		int i;
2366 		int offset;
2367 		sector_t write_pos;
2368 
2369 		WARN_ON(!test_bit(STRIPE_R5C_CACHING, &sh->state));
2370 		r5l_recovery_create_empty_meta_block(log, page,
2371 						     ctx->pos, ctx->seq);
2372 		mb = page_address(page);
2373 		offset = le32_to_cpu(mb->meta_size);
2374 		write_pos = r5l_ring_add(log, ctx->pos, BLOCK_SECTORS);
2375 
2376 		for (i = sh->disks; i--; ) {
2377 			struct r5dev *dev = &sh->dev[i];
2378 			struct r5l_payload_data_parity *payload;
2379 			void *addr;
2380 
2381 			if (test_bit(R5_InJournal, &dev->flags)) {
2382 				payload = (void *)mb + offset;
2383 				payload->header.type = cpu_to_le16(
2384 					R5LOG_PAYLOAD_DATA);
2385 				payload->size = cpu_to_le32(BLOCK_SECTORS);
2386 				payload->location = cpu_to_le64(
2387 					raid5_compute_blocknr(sh, i, 0));
2388 				addr = kmap_atomic(dev->page);
2389 				payload->checksum[0] = cpu_to_le32(
2390 					crc32c_le(log->uuid_checksum, addr,
2391 						  PAGE_SIZE));
2392 				kunmap_atomic(addr);
2393 				sync_page_io(log->rdev, write_pos, PAGE_SIZE,
2394 					     dev->page, REQ_OP_WRITE, false);
2395 				write_pos = r5l_ring_add(log, write_pos,
2396 							 BLOCK_SECTORS);
2397 				offset += sizeof(__le32) +
2398 					sizeof(struct r5l_payload_data_parity);
2399 
2400 			}
2401 		}
2402 		mb->meta_size = cpu_to_le32(offset);
2403 		mb->checksum = cpu_to_le32(crc32c_le(log->uuid_checksum,
2404 						     mb, PAGE_SIZE));
2405 		sync_page_io(log->rdev, ctx->pos, PAGE_SIZE, page,
2406 			     REQ_OP_WRITE | REQ_SYNC | REQ_FUA, false);
2407 		sh->log_start = ctx->pos;
2408 		list_add_tail(&sh->r5c, &log->stripe_in_journal_list);
2409 		atomic_inc(&log->stripe_in_journal_count);
2410 		ctx->pos = write_pos;
2411 		ctx->seq += 1;
2412 		next_checkpoint = sh->log_start;
2413 	}
2414 	log->next_checkpoint = next_checkpoint;
2415 	__free_page(page);
2416 	return 0;
2417 }
2418 
r5c_recovery_flush_data_only_stripes(struct r5l_log * log,struct r5l_recovery_ctx * ctx)2419 static void r5c_recovery_flush_data_only_stripes(struct r5l_log *log,
2420 						 struct r5l_recovery_ctx *ctx)
2421 {
2422 	struct mddev *mddev = log->rdev->mddev;
2423 	struct r5conf *conf = mddev->private;
2424 	struct stripe_head *sh, *next;
2425 	bool cleared_pending = false;
2426 
2427 	if (ctx->data_only_stripes == 0)
2428 		return;
2429 
2430 	if (test_bit(MD_SB_CHANGE_PENDING, &mddev->sb_flags)) {
2431 		cleared_pending = true;
2432 		clear_bit(MD_SB_CHANGE_PENDING, &mddev->sb_flags);
2433 	}
2434 	log->r5c_journal_mode = R5C_JOURNAL_MODE_WRITE_BACK;
2435 
2436 	list_for_each_entry_safe(sh, next, &ctx->cached_list, lru) {
2437 		r5c_make_stripe_write_out(sh);
2438 		set_bit(STRIPE_HANDLE, &sh->state);
2439 		list_del_init(&sh->lru);
2440 		raid5_release_stripe(sh);
2441 	}
2442 
2443 	/* reuse conf->wait_for_quiescent in recovery */
2444 	wait_event(conf->wait_for_quiescent,
2445 		   atomic_read(&conf->active_stripes) == 0);
2446 
2447 	log->r5c_journal_mode = R5C_JOURNAL_MODE_WRITE_THROUGH;
2448 	if (cleared_pending)
2449 		set_bit(MD_SB_CHANGE_PENDING, &mddev->sb_flags);
2450 }
2451 
r5l_recovery_log(struct r5l_log * log)2452 static int r5l_recovery_log(struct r5l_log *log)
2453 {
2454 	struct mddev *mddev = log->rdev->mddev;
2455 	struct r5l_recovery_ctx *ctx;
2456 	int ret;
2457 	sector_t pos;
2458 
2459 	ctx = kzalloc(sizeof(*ctx), GFP_KERNEL);
2460 	if (!ctx)
2461 		return -ENOMEM;
2462 
2463 	ctx->pos = log->last_checkpoint;
2464 	ctx->seq = log->last_cp_seq;
2465 	INIT_LIST_HEAD(&ctx->cached_list);
2466 	ctx->meta_page = alloc_page(GFP_KERNEL);
2467 
2468 	if (!ctx->meta_page) {
2469 		ret =  -ENOMEM;
2470 		goto meta_page;
2471 	}
2472 
2473 	if (r5l_recovery_allocate_ra_pool(log, ctx) != 0) {
2474 		ret = -ENOMEM;
2475 		goto ra_pool;
2476 	}
2477 
2478 	ret = r5c_recovery_flush_log(log, ctx);
2479 
2480 	if (ret)
2481 		goto error;
2482 
2483 	pos = ctx->pos;
2484 	ctx->seq += 10000;
2485 
2486 	if ((ctx->data_only_stripes == 0) && (ctx->data_parity_stripes == 0))
2487 		pr_info("md/raid:%s: starting from clean shutdown\n",
2488 			 mdname(mddev));
2489 	else
2490 		pr_info("md/raid:%s: recovering %d data-only stripes and %d data-parity stripes\n",
2491 			 mdname(mddev), ctx->data_only_stripes,
2492 			 ctx->data_parity_stripes);
2493 
2494 	if (ctx->data_only_stripes == 0) {
2495 		log->next_checkpoint = ctx->pos;
2496 		r5l_log_write_empty_meta_block(log, ctx->pos, ctx->seq++);
2497 		ctx->pos = r5l_ring_add(log, ctx->pos, BLOCK_SECTORS);
2498 	} else if (r5c_recovery_rewrite_data_only_stripes(log, ctx)) {
2499 		pr_err("md/raid:%s: failed to rewrite stripes to journal\n",
2500 		       mdname(mddev));
2501 		ret =  -EIO;
2502 		goto error;
2503 	}
2504 
2505 	log->log_start = ctx->pos;
2506 	log->seq = ctx->seq;
2507 	log->last_checkpoint = pos;
2508 	r5l_write_super(log, pos);
2509 
2510 	r5c_recovery_flush_data_only_stripes(log, ctx);
2511 	ret = 0;
2512 error:
2513 	r5l_recovery_free_ra_pool(log, ctx);
2514 ra_pool:
2515 	__free_page(ctx->meta_page);
2516 meta_page:
2517 	kfree(ctx);
2518 	return ret;
2519 }
2520 
r5l_write_super(struct r5l_log * log,sector_t cp)2521 static void r5l_write_super(struct r5l_log *log, sector_t cp)
2522 {
2523 	struct mddev *mddev = log->rdev->mddev;
2524 
2525 	log->rdev->journal_tail = cp;
2526 	set_bit(MD_SB_CHANGE_DEVS, &mddev->sb_flags);
2527 }
2528 
r5c_journal_mode_show(struct mddev * mddev,char * page)2529 static ssize_t r5c_journal_mode_show(struct mddev *mddev, char *page)
2530 {
2531 	struct r5conf *conf;
2532 	int ret;
2533 
2534 	ret = mddev_lock(mddev);
2535 	if (ret)
2536 		return ret;
2537 
2538 	conf = mddev->private;
2539 	if (!conf || !conf->log)
2540 		goto out_unlock;
2541 
2542 	switch (conf->log->r5c_journal_mode) {
2543 	case R5C_JOURNAL_MODE_WRITE_THROUGH:
2544 		ret = snprintf(
2545 			page, PAGE_SIZE, "[%s] %s\n",
2546 			r5c_journal_mode_str[R5C_JOURNAL_MODE_WRITE_THROUGH],
2547 			r5c_journal_mode_str[R5C_JOURNAL_MODE_WRITE_BACK]);
2548 		break;
2549 	case R5C_JOURNAL_MODE_WRITE_BACK:
2550 		ret = snprintf(
2551 			page, PAGE_SIZE, "%s [%s]\n",
2552 			r5c_journal_mode_str[R5C_JOURNAL_MODE_WRITE_THROUGH],
2553 			r5c_journal_mode_str[R5C_JOURNAL_MODE_WRITE_BACK]);
2554 		break;
2555 	default:
2556 		ret = 0;
2557 	}
2558 
2559 out_unlock:
2560 	mddev_unlock(mddev);
2561 	return ret;
2562 }
2563 
2564 /*
2565  * Set journal cache mode on @mddev (external API initially needed by dm-raid).
2566  *
2567  * @mode as defined in 'enum r5c_journal_mode'.
2568  *
2569  */
r5c_journal_mode_set(struct mddev * mddev,int mode)2570 int r5c_journal_mode_set(struct mddev *mddev, int mode)
2571 {
2572 	struct r5conf *conf;
2573 
2574 	if (mode < R5C_JOURNAL_MODE_WRITE_THROUGH ||
2575 	    mode > R5C_JOURNAL_MODE_WRITE_BACK)
2576 		return -EINVAL;
2577 
2578 	conf = mddev->private;
2579 	if (!conf || !conf->log)
2580 		return -ENODEV;
2581 
2582 	if (raid5_calc_degraded(conf) > 0 &&
2583 	    mode == R5C_JOURNAL_MODE_WRITE_BACK)
2584 		return -EINVAL;
2585 
2586 	mddev_suspend(mddev);
2587 	conf->log->r5c_journal_mode = mode;
2588 	mddev_resume(mddev);
2589 
2590 	pr_debug("md/raid:%s: setting r5c cache mode to %d: %s\n",
2591 		 mdname(mddev), mode, r5c_journal_mode_str[mode]);
2592 	return 0;
2593 }
2594 EXPORT_SYMBOL(r5c_journal_mode_set);
2595 
r5c_journal_mode_store(struct mddev * mddev,const char * page,size_t length)2596 static ssize_t r5c_journal_mode_store(struct mddev *mddev,
2597 				      const char *page, size_t length)
2598 {
2599 	int mode = ARRAY_SIZE(r5c_journal_mode_str);
2600 	size_t len = length;
2601 	int ret;
2602 
2603 	if (len < 2)
2604 		return -EINVAL;
2605 
2606 	if (page[len - 1] == '\n')
2607 		len--;
2608 
2609 	while (mode--)
2610 		if (strlen(r5c_journal_mode_str[mode]) == len &&
2611 		    !strncmp(page, r5c_journal_mode_str[mode], len))
2612 			break;
2613 	ret = mddev_lock(mddev);
2614 	if (ret)
2615 		return ret;
2616 	ret = r5c_journal_mode_set(mddev, mode);
2617 	mddev_unlock(mddev);
2618 	return ret ?: length;
2619 }
2620 
2621 struct md_sysfs_entry
2622 r5c_journal_mode = __ATTR(journal_mode, 0644,
2623 			  r5c_journal_mode_show, r5c_journal_mode_store);
2624 
2625 /*
2626  * Try handle write operation in caching phase. This function should only
2627  * be called in write-back mode.
2628  *
2629  * If all outstanding writes can be handled in caching phase, returns 0
2630  * If writes requires write-out phase, call r5c_make_stripe_write_out()
2631  * and returns -EAGAIN
2632  */
r5c_try_caching_write(struct r5conf * conf,struct stripe_head * sh,struct stripe_head_state * s,int disks)2633 int r5c_try_caching_write(struct r5conf *conf,
2634 			  struct stripe_head *sh,
2635 			  struct stripe_head_state *s,
2636 			  int disks)
2637 {
2638 	struct r5l_log *log = conf->log;
2639 	int i;
2640 	struct r5dev *dev;
2641 	int to_cache = 0;
2642 	void __rcu **pslot;
2643 	sector_t tree_index;
2644 	int ret;
2645 	uintptr_t refcount;
2646 
2647 	BUG_ON(!r5c_is_writeback(log));
2648 
2649 	if (!test_bit(STRIPE_R5C_CACHING, &sh->state)) {
2650 		/*
2651 		 * There are two different scenarios here:
2652 		 *  1. The stripe has some data cached, and it is sent to
2653 		 *     write-out phase for reclaim
2654 		 *  2. The stripe is clean, and this is the first write
2655 		 *
2656 		 * For 1, return -EAGAIN, so we continue with
2657 		 * handle_stripe_dirtying().
2658 		 *
2659 		 * For 2, set STRIPE_R5C_CACHING and continue with caching
2660 		 * write.
2661 		 */
2662 
2663 		/* case 1: anything injournal or anything in written */
2664 		if (s->injournal > 0 || s->written > 0)
2665 			return -EAGAIN;
2666 		/* case 2 */
2667 		set_bit(STRIPE_R5C_CACHING, &sh->state);
2668 	}
2669 
2670 	/*
2671 	 * When run in degraded mode, array is set to write-through mode.
2672 	 * This check helps drain pending write safely in the transition to
2673 	 * write-through mode.
2674 	 *
2675 	 * When a stripe is syncing, the write is also handled in write
2676 	 * through mode.
2677 	 */
2678 	if (s->failed || test_bit(STRIPE_SYNCING, &sh->state)) {
2679 		r5c_make_stripe_write_out(sh);
2680 		return -EAGAIN;
2681 	}
2682 
2683 	for (i = disks; i--; ) {
2684 		dev = &sh->dev[i];
2685 		/* if non-overwrite, use writing-out phase */
2686 		if (dev->towrite && !test_bit(R5_OVERWRITE, &dev->flags) &&
2687 		    !test_bit(R5_InJournal, &dev->flags)) {
2688 			r5c_make_stripe_write_out(sh);
2689 			return -EAGAIN;
2690 		}
2691 	}
2692 
2693 	/* if the stripe is not counted in big_stripe_tree, add it now */
2694 	if (!test_bit(STRIPE_R5C_PARTIAL_STRIPE, &sh->state) &&
2695 	    !test_bit(STRIPE_R5C_FULL_STRIPE, &sh->state)) {
2696 		tree_index = r5c_tree_index(conf, sh->sector);
2697 		spin_lock(&log->tree_lock);
2698 		pslot = radix_tree_lookup_slot(&log->big_stripe_tree,
2699 					       tree_index);
2700 		if (pslot) {
2701 			refcount = (uintptr_t)radix_tree_deref_slot_protected(
2702 				pslot, &log->tree_lock) >>
2703 				R5C_RADIX_COUNT_SHIFT;
2704 			radix_tree_replace_slot(
2705 				&log->big_stripe_tree, pslot,
2706 				(void *)((refcount + 1) << R5C_RADIX_COUNT_SHIFT));
2707 		} else {
2708 			/*
2709 			 * this radix_tree_insert can fail safely, so no
2710 			 * need to call radix_tree_preload()
2711 			 */
2712 			ret = radix_tree_insert(
2713 				&log->big_stripe_tree, tree_index,
2714 				(void *)(1 << R5C_RADIX_COUNT_SHIFT));
2715 			if (ret) {
2716 				spin_unlock(&log->tree_lock);
2717 				r5c_make_stripe_write_out(sh);
2718 				return -EAGAIN;
2719 			}
2720 		}
2721 		spin_unlock(&log->tree_lock);
2722 
2723 		/*
2724 		 * set STRIPE_R5C_PARTIAL_STRIPE, this shows the stripe is
2725 		 * counted in the radix tree
2726 		 */
2727 		set_bit(STRIPE_R5C_PARTIAL_STRIPE, &sh->state);
2728 		atomic_inc(&conf->r5c_cached_partial_stripes);
2729 	}
2730 
2731 	for (i = disks; i--; ) {
2732 		dev = &sh->dev[i];
2733 		if (dev->towrite) {
2734 			set_bit(R5_Wantwrite, &dev->flags);
2735 			set_bit(R5_Wantdrain, &dev->flags);
2736 			set_bit(R5_LOCKED, &dev->flags);
2737 			to_cache++;
2738 		}
2739 	}
2740 
2741 	if (to_cache) {
2742 		set_bit(STRIPE_OP_BIODRAIN, &s->ops_request);
2743 		/*
2744 		 * set STRIPE_LOG_TRAPPED, which triggers r5c_cache_data()
2745 		 * in ops_run_io(). STRIPE_LOG_TRAPPED will be cleared in
2746 		 * r5c_handle_data_cached()
2747 		 */
2748 		set_bit(STRIPE_LOG_TRAPPED, &sh->state);
2749 	}
2750 
2751 	return 0;
2752 }
2753 
2754 /*
2755  * free extra pages (orig_page) we allocated for prexor
2756  */
r5c_release_extra_page(struct stripe_head * sh)2757 void r5c_release_extra_page(struct stripe_head *sh)
2758 {
2759 	struct r5conf *conf = sh->raid_conf;
2760 	int i;
2761 	bool using_disk_info_extra_page;
2762 
2763 	using_disk_info_extra_page =
2764 		sh->dev[0].orig_page == conf->disks[0].extra_page;
2765 
2766 	for (i = sh->disks; i--; )
2767 		if (sh->dev[i].page != sh->dev[i].orig_page) {
2768 			struct page *p = sh->dev[i].orig_page;
2769 
2770 			sh->dev[i].orig_page = sh->dev[i].page;
2771 			clear_bit(R5_OrigPageUPTDODATE, &sh->dev[i].flags);
2772 
2773 			if (!using_disk_info_extra_page)
2774 				put_page(p);
2775 		}
2776 
2777 	if (using_disk_info_extra_page) {
2778 		clear_bit(R5C_EXTRA_PAGE_IN_USE, &conf->cache_state);
2779 		md_wakeup_thread(conf->mddev->thread);
2780 	}
2781 }
2782 
r5c_use_extra_page(struct stripe_head * sh)2783 void r5c_use_extra_page(struct stripe_head *sh)
2784 {
2785 	struct r5conf *conf = sh->raid_conf;
2786 	int i;
2787 	struct r5dev *dev;
2788 
2789 	for (i = sh->disks; i--; ) {
2790 		dev = &sh->dev[i];
2791 		if (dev->orig_page != dev->page)
2792 			put_page(dev->orig_page);
2793 		dev->orig_page = conf->disks[i].extra_page;
2794 	}
2795 }
2796 
2797 /*
2798  * clean up the stripe (clear R5_InJournal for dev[pd_idx] etc.) after the
2799  * stripe is committed to RAID disks.
2800  */
r5c_finish_stripe_write_out(struct r5conf * conf,struct stripe_head * sh,struct stripe_head_state * s)2801 void r5c_finish_stripe_write_out(struct r5conf *conf,
2802 				 struct stripe_head *sh,
2803 				 struct stripe_head_state *s)
2804 {
2805 	struct r5l_log *log = conf->log;
2806 	int i;
2807 	int do_wakeup = 0;
2808 	sector_t tree_index;
2809 	void __rcu **pslot;
2810 	uintptr_t refcount;
2811 
2812 	if (!log || !test_bit(R5_InJournal, &sh->dev[sh->pd_idx].flags))
2813 		return;
2814 
2815 	WARN_ON(test_bit(STRIPE_R5C_CACHING, &sh->state));
2816 	clear_bit(R5_InJournal, &sh->dev[sh->pd_idx].flags);
2817 
2818 	if (log->r5c_journal_mode == R5C_JOURNAL_MODE_WRITE_THROUGH)
2819 		return;
2820 
2821 	for (i = sh->disks; i--; ) {
2822 		clear_bit(R5_InJournal, &sh->dev[i].flags);
2823 		if (test_and_clear_bit(R5_Overlap, &sh->dev[i].flags))
2824 			do_wakeup = 1;
2825 	}
2826 
2827 	/*
2828 	 * analyse_stripe() runs before r5c_finish_stripe_write_out(),
2829 	 * We updated R5_InJournal, so we also update s->injournal.
2830 	 */
2831 	s->injournal = 0;
2832 
2833 	if (test_and_clear_bit(STRIPE_FULL_WRITE, &sh->state))
2834 		if (atomic_dec_and_test(&conf->pending_full_writes))
2835 			md_wakeup_thread(conf->mddev->thread);
2836 
2837 	if (do_wakeup)
2838 		wake_up(&conf->wait_for_overlap);
2839 
2840 	spin_lock_irq(&log->stripe_in_journal_lock);
2841 	list_del_init(&sh->r5c);
2842 	spin_unlock_irq(&log->stripe_in_journal_lock);
2843 	sh->log_start = MaxSector;
2844 
2845 	atomic_dec(&log->stripe_in_journal_count);
2846 	r5c_update_log_state(log);
2847 
2848 	/* stop counting this stripe in big_stripe_tree */
2849 	if (test_bit(STRIPE_R5C_PARTIAL_STRIPE, &sh->state) ||
2850 	    test_bit(STRIPE_R5C_FULL_STRIPE, &sh->state)) {
2851 		tree_index = r5c_tree_index(conf, sh->sector);
2852 		spin_lock(&log->tree_lock);
2853 		pslot = radix_tree_lookup_slot(&log->big_stripe_tree,
2854 					       tree_index);
2855 		BUG_ON(pslot == NULL);
2856 		refcount = (uintptr_t)radix_tree_deref_slot_protected(
2857 			pslot, &log->tree_lock) >>
2858 			R5C_RADIX_COUNT_SHIFT;
2859 		if (refcount == 1)
2860 			radix_tree_delete(&log->big_stripe_tree, tree_index);
2861 		else
2862 			radix_tree_replace_slot(
2863 				&log->big_stripe_tree, pslot,
2864 				(void *)((refcount - 1) << R5C_RADIX_COUNT_SHIFT));
2865 		spin_unlock(&log->tree_lock);
2866 	}
2867 
2868 	if (test_and_clear_bit(STRIPE_R5C_PARTIAL_STRIPE, &sh->state)) {
2869 		BUG_ON(atomic_read(&conf->r5c_cached_partial_stripes) == 0);
2870 		atomic_dec(&conf->r5c_flushing_partial_stripes);
2871 		atomic_dec(&conf->r5c_cached_partial_stripes);
2872 	}
2873 
2874 	if (test_and_clear_bit(STRIPE_R5C_FULL_STRIPE, &sh->state)) {
2875 		BUG_ON(atomic_read(&conf->r5c_cached_full_stripes) == 0);
2876 		atomic_dec(&conf->r5c_flushing_full_stripes);
2877 		atomic_dec(&conf->r5c_cached_full_stripes);
2878 	}
2879 
2880 	r5l_append_flush_payload(log, sh->sector);
2881 	/* stripe is flused to raid disks, we can do resync now */
2882 	if (test_bit(STRIPE_SYNC_REQUESTED, &sh->state))
2883 		set_bit(STRIPE_HANDLE, &sh->state);
2884 }
2885 
r5c_cache_data(struct r5l_log * log,struct stripe_head * sh)2886 int r5c_cache_data(struct r5l_log *log, struct stripe_head *sh)
2887 {
2888 	struct r5conf *conf = sh->raid_conf;
2889 	int pages = 0;
2890 	int reserve;
2891 	int i;
2892 	int ret = 0;
2893 
2894 	BUG_ON(!log);
2895 
2896 	for (i = 0; i < sh->disks; i++) {
2897 		void *addr;
2898 
2899 		if (!test_bit(R5_Wantwrite, &sh->dev[i].flags))
2900 			continue;
2901 		addr = kmap_atomic(sh->dev[i].page);
2902 		sh->dev[i].log_checksum = crc32c_le(log->uuid_checksum,
2903 						    addr, PAGE_SIZE);
2904 		kunmap_atomic(addr);
2905 		pages++;
2906 	}
2907 	WARN_ON(pages == 0);
2908 
2909 	/*
2910 	 * The stripe must enter state machine again to call endio, so
2911 	 * don't delay.
2912 	 */
2913 	clear_bit(STRIPE_DELAYED, &sh->state);
2914 	atomic_inc(&sh->count);
2915 
2916 	mutex_lock(&log->io_mutex);
2917 	/* meta + data */
2918 	reserve = (1 + pages) << (PAGE_SHIFT - 9);
2919 
2920 	if (test_bit(R5C_LOG_CRITICAL, &conf->cache_state) &&
2921 	    sh->log_start == MaxSector)
2922 		r5l_add_no_space_stripe(log, sh);
2923 	else if (!r5l_has_free_space(log, reserve)) {
2924 		if (sh->log_start == log->last_checkpoint)
2925 			BUG();
2926 		else
2927 			r5l_add_no_space_stripe(log, sh);
2928 	} else {
2929 		ret = r5l_log_stripe(log, sh, pages, 0);
2930 		if (ret) {
2931 			spin_lock_irq(&log->io_list_lock);
2932 			list_add_tail(&sh->log_list, &log->no_mem_stripes);
2933 			spin_unlock_irq(&log->io_list_lock);
2934 		}
2935 	}
2936 
2937 	mutex_unlock(&log->io_mutex);
2938 	return 0;
2939 }
2940 
2941 /* check whether this big stripe is in write back cache. */
r5c_big_stripe_cached(struct r5conf * conf,sector_t sect)2942 bool r5c_big_stripe_cached(struct r5conf *conf, sector_t sect)
2943 {
2944 	struct r5l_log *log = conf->log;
2945 	sector_t tree_index;
2946 	void *slot;
2947 
2948 	if (!log)
2949 		return false;
2950 
2951 	WARN_ON_ONCE(!rcu_read_lock_held());
2952 	tree_index = r5c_tree_index(conf, sect);
2953 	slot = radix_tree_lookup(&log->big_stripe_tree, tree_index);
2954 	return slot != NULL;
2955 }
2956 
r5l_load_log(struct r5l_log * log)2957 static int r5l_load_log(struct r5l_log *log)
2958 {
2959 	struct md_rdev *rdev = log->rdev;
2960 	struct page *page;
2961 	struct r5l_meta_block *mb;
2962 	sector_t cp = log->rdev->journal_tail;
2963 	u32 stored_crc, expected_crc;
2964 	bool create_super = false;
2965 	int ret = 0;
2966 
2967 	/* Make sure it's valid */
2968 	if (cp >= rdev->sectors || round_down(cp, BLOCK_SECTORS) != cp)
2969 		cp = 0;
2970 	page = alloc_page(GFP_KERNEL);
2971 	if (!page)
2972 		return -ENOMEM;
2973 
2974 	if (!sync_page_io(rdev, cp, PAGE_SIZE, page, REQ_OP_READ, false)) {
2975 		ret = -EIO;
2976 		goto ioerr;
2977 	}
2978 	mb = page_address(page);
2979 
2980 	if (le32_to_cpu(mb->magic) != R5LOG_MAGIC ||
2981 	    mb->version != R5LOG_VERSION) {
2982 		create_super = true;
2983 		goto create;
2984 	}
2985 	stored_crc = le32_to_cpu(mb->checksum);
2986 	mb->checksum = 0;
2987 	expected_crc = crc32c_le(log->uuid_checksum, mb, PAGE_SIZE);
2988 	if (stored_crc != expected_crc) {
2989 		create_super = true;
2990 		goto create;
2991 	}
2992 	if (le64_to_cpu(mb->position) != cp) {
2993 		create_super = true;
2994 		goto create;
2995 	}
2996 create:
2997 	if (create_super) {
2998 		log->last_cp_seq = get_random_u32();
2999 		cp = 0;
3000 		r5l_log_write_empty_meta_block(log, cp, log->last_cp_seq);
3001 		/*
3002 		 * Make sure super points to correct address. Log might have
3003 		 * data very soon. If super hasn't correct log tail address,
3004 		 * recovery can't find the log
3005 		 */
3006 		r5l_write_super(log, cp);
3007 	} else
3008 		log->last_cp_seq = le64_to_cpu(mb->seq);
3009 
3010 	log->device_size = round_down(rdev->sectors, BLOCK_SECTORS);
3011 	log->max_free_space = log->device_size >> RECLAIM_MAX_FREE_SPACE_SHIFT;
3012 	if (log->max_free_space > RECLAIM_MAX_FREE_SPACE)
3013 		log->max_free_space = RECLAIM_MAX_FREE_SPACE;
3014 	log->last_checkpoint = cp;
3015 
3016 	__free_page(page);
3017 
3018 	if (create_super) {
3019 		log->log_start = r5l_ring_add(log, cp, BLOCK_SECTORS);
3020 		log->seq = log->last_cp_seq + 1;
3021 		log->next_checkpoint = cp;
3022 	} else
3023 		ret = r5l_recovery_log(log);
3024 
3025 	r5c_update_log_state(log);
3026 	return ret;
3027 ioerr:
3028 	__free_page(page);
3029 	return ret;
3030 }
3031 
r5l_start(struct r5l_log * log)3032 int r5l_start(struct r5l_log *log)
3033 {
3034 	int ret;
3035 
3036 	if (!log)
3037 		return 0;
3038 
3039 	ret = r5l_load_log(log);
3040 	if (ret) {
3041 		struct mddev *mddev = log->rdev->mddev;
3042 		struct r5conf *conf = mddev->private;
3043 
3044 		r5l_exit_log(conf);
3045 	}
3046 	return ret;
3047 }
3048 
r5c_update_on_rdev_error(struct mddev * mddev,struct md_rdev * rdev)3049 void r5c_update_on_rdev_error(struct mddev *mddev, struct md_rdev *rdev)
3050 {
3051 	struct r5conf *conf = mddev->private;
3052 	struct r5l_log *log = conf->log;
3053 
3054 	if (!log)
3055 		return;
3056 
3057 	if ((raid5_calc_degraded(conf) > 0 ||
3058 	     test_bit(Journal, &rdev->flags)) &&
3059 	    conf->log->r5c_journal_mode == R5C_JOURNAL_MODE_WRITE_BACK)
3060 		schedule_work(&log->disable_writeback_work);
3061 }
3062 
r5l_init_log(struct r5conf * conf,struct md_rdev * rdev)3063 int r5l_init_log(struct r5conf *conf, struct md_rdev *rdev)
3064 {
3065 	struct r5l_log *log;
3066 	struct md_thread *thread;
3067 	int ret;
3068 
3069 	pr_debug("md/raid:%s: using device %pg as journal\n",
3070 		 mdname(conf->mddev), rdev->bdev);
3071 
3072 	if (PAGE_SIZE != 4096)
3073 		return -EINVAL;
3074 
3075 	/*
3076 	 * The PAGE_SIZE must be big enough to hold 1 r5l_meta_block and
3077 	 * raid_disks r5l_payload_data_parity.
3078 	 *
3079 	 * Write journal and cache does not work for very big array
3080 	 * (raid_disks > 203)
3081 	 */
3082 	if (sizeof(struct r5l_meta_block) +
3083 	    ((sizeof(struct r5l_payload_data_parity) + sizeof(__le32)) *
3084 	     conf->raid_disks) > PAGE_SIZE) {
3085 		pr_err("md/raid:%s: write journal/cache doesn't work for array with %d disks\n",
3086 		       mdname(conf->mddev), conf->raid_disks);
3087 		return -EINVAL;
3088 	}
3089 
3090 	log = kzalloc(sizeof(*log), GFP_KERNEL);
3091 	if (!log)
3092 		return -ENOMEM;
3093 	log->rdev = rdev;
3094 	log->need_cache_flush = bdev_write_cache(rdev->bdev);
3095 	log->uuid_checksum = crc32c_le(~0, rdev->mddev->uuid,
3096 				       sizeof(rdev->mddev->uuid));
3097 
3098 	mutex_init(&log->io_mutex);
3099 
3100 	spin_lock_init(&log->io_list_lock);
3101 	INIT_LIST_HEAD(&log->running_ios);
3102 	INIT_LIST_HEAD(&log->io_end_ios);
3103 	INIT_LIST_HEAD(&log->flushing_ios);
3104 	INIT_LIST_HEAD(&log->finished_ios);
3105 
3106 	log->io_kc = KMEM_CACHE(r5l_io_unit, 0);
3107 	if (!log->io_kc)
3108 		goto io_kc;
3109 
3110 	ret = mempool_init_slab_pool(&log->io_pool, R5L_POOL_SIZE, log->io_kc);
3111 	if (ret)
3112 		goto io_pool;
3113 
3114 	ret = bioset_init(&log->bs, R5L_POOL_SIZE, 0, BIOSET_NEED_BVECS);
3115 	if (ret)
3116 		goto io_bs;
3117 
3118 	ret = mempool_init_page_pool(&log->meta_pool, R5L_POOL_SIZE, 0);
3119 	if (ret)
3120 		goto out_mempool;
3121 
3122 	spin_lock_init(&log->tree_lock);
3123 	INIT_RADIX_TREE(&log->big_stripe_tree, GFP_NOWAIT | __GFP_NOWARN);
3124 
3125 	thread = md_register_thread(r5l_reclaim_thread, log->rdev->mddev,
3126 				    "reclaim");
3127 	if (!thread)
3128 		goto reclaim_thread;
3129 
3130 	thread->timeout = R5C_RECLAIM_WAKEUP_INTERVAL;
3131 	rcu_assign_pointer(log->reclaim_thread, thread);
3132 
3133 	init_waitqueue_head(&log->iounit_wait);
3134 
3135 	INIT_LIST_HEAD(&log->no_mem_stripes);
3136 
3137 	INIT_LIST_HEAD(&log->no_space_stripes);
3138 	spin_lock_init(&log->no_space_stripes_lock);
3139 
3140 	INIT_WORK(&log->deferred_io_work, r5l_submit_io_async);
3141 	INIT_WORK(&log->disable_writeback_work, r5c_disable_writeback_async);
3142 
3143 	log->r5c_journal_mode = R5C_JOURNAL_MODE_WRITE_THROUGH;
3144 	INIT_LIST_HEAD(&log->stripe_in_journal_list);
3145 	spin_lock_init(&log->stripe_in_journal_lock);
3146 	atomic_set(&log->stripe_in_journal_count, 0);
3147 
3148 	conf->log = log;
3149 
3150 	set_bit(MD_HAS_JOURNAL, &conf->mddev->flags);
3151 	return 0;
3152 
3153 reclaim_thread:
3154 	mempool_exit(&log->meta_pool);
3155 out_mempool:
3156 	bioset_exit(&log->bs);
3157 io_bs:
3158 	mempool_exit(&log->io_pool);
3159 io_pool:
3160 	kmem_cache_destroy(log->io_kc);
3161 io_kc:
3162 	kfree(log);
3163 	return -EINVAL;
3164 }
3165 
r5l_exit_log(struct r5conf * conf)3166 void r5l_exit_log(struct r5conf *conf)
3167 {
3168 	struct r5l_log *log = conf->log;
3169 
3170 	md_unregister_thread(conf->mddev, &log->reclaim_thread);
3171 
3172 	/*
3173 	 * 'reconfig_mutex' is held by caller, set 'confg->log' to NULL to
3174 	 * ensure disable_writeback_work wakes up and exits.
3175 	 */
3176 	conf->log = NULL;
3177 	wake_up(&conf->mddev->sb_wait);
3178 	flush_work(&log->disable_writeback_work);
3179 
3180 	mempool_exit(&log->meta_pool);
3181 	bioset_exit(&log->bs);
3182 	mempool_exit(&log->io_pool);
3183 	kmem_cache_destroy(log->io_kc);
3184 	kfree(log);
3185 }
3186