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 *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 					 * dones'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(GFP_NOIO, BIO_MAX_VECS, &log->bs);
739 
740 	bio_set_op_attrs(bio, REQ_OP_WRITE, 0);
741 	bio_set_dev(bio, log->rdev->bdev);
742 	bio->bi_iter.bi_sector = log->rdev->data_offset + log->log_start;
743 
744 	return bio;
745 }
746 
r5_reserve_log_entry(struct r5l_log * log,struct r5l_io_unit * io)747 static void r5_reserve_log_entry(struct r5l_log *log, struct r5l_io_unit *io)
748 {
749 	log->log_start = r5l_ring_add(log, log->log_start, BLOCK_SECTORS);
750 
751 	r5c_update_log_state(log);
752 	/*
753 	 * If we filled up the log device start from the beginning again,
754 	 * which will require a new bio.
755 	 *
756 	 * Note: for this to work properly the log size needs to me a multiple
757 	 * of BLOCK_SECTORS.
758 	 */
759 	if (log->log_start == 0)
760 		io->need_split_bio = true;
761 
762 	io->log_end = log->log_start;
763 }
764 
r5l_new_meta(struct r5l_log * log)765 static struct r5l_io_unit *r5l_new_meta(struct r5l_log *log)
766 {
767 	struct r5l_io_unit *io;
768 	struct r5l_meta_block *block;
769 
770 	io = mempool_alloc(&log->io_pool, GFP_ATOMIC);
771 	if (!io)
772 		return NULL;
773 	memset(io, 0, sizeof(*io));
774 
775 	io->log = log;
776 	INIT_LIST_HEAD(&io->log_sibling);
777 	INIT_LIST_HEAD(&io->stripe_list);
778 	bio_list_init(&io->flush_barriers);
779 	io->state = IO_UNIT_RUNNING;
780 
781 	io->meta_page = mempool_alloc(&log->meta_pool, GFP_NOIO);
782 	block = page_address(io->meta_page);
783 	clear_page(block);
784 	block->magic = cpu_to_le32(R5LOG_MAGIC);
785 	block->version = R5LOG_VERSION;
786 	block->seq = cpu_to_le64(log->seq);
787 	block->position = cpu_to_le64(log->log_start);
788 
789 	io->log_start = log->log_start;
790 	io->meta_offset = sizeof(struct r5l_meta_block);
791 	io->seq = log->seq++;
792 
793 	io->current_bio = r5l_bio_alloc(log);
794 	io->current_bio->bi_end_io = r5l_log_endio;
795 	io->current_bio->bi_private = io;
796 	bio_add_page(io->current_bio, io->meta_page, PAGE_SIZE, 0);
797 
798 	r5_reserve_log_entry(log, io);
799 
800 	spin_lock_irq(&log->io_list_lock);
801 	list_add_tail(&io->log_sibling, &log->running_ios);
802 	spin_unlock_irq(&log->io_list_lock);
803 
804 	return io;
805 }
806 
r5l_get_meta(struct r5l_log * log,unsigned int payload_size)807 static int r5l_get_meta(struct r5l_log *log, unsigned int payload_size)
808 {
809 	if (log->current_io &&
810 	    log->current_io->meta_offset + payload_size > PAGE_SIZE)
811 		r5l_submit_current_io(log);
812 
813 	if (!log->current_io) {
814 		log->current_io = r5l_new_meta(log);
815 		if (!log->current_io)
816 			return -ENOMEM;
817 	}
818 
819 	return 0;
820 }
821 
r5l_append_payload_meta(struct r5l_log * log,u16 type,sector_t location,u32 checksum1,u32 checksum2,bool checksum2_valid)822 static void r5l_append_payload_meta(struct r5l_log *log, u16 type,
823 				    sector_t location,
824 				    u32 checksum1, u32 checksum2,
825 				    bool checksum2_valid)
826 {
827 	struct r5l_io_unit *io = log->current_io;
828 	struct r5l_payload_data_parity *payload;
829 
830 	payload = page_address(io->meta_page) + io->meta_offset;
831 	payload->header.type = cpu_to_le16(type);
832 	payload->header.flags = cpu_to_le16(0);
833 	payload->size = cpu_to_le32((1 + !!checksum2_valid) <<
834 				    (PAGE_SHIFT - 9));
835 	payload->location = cpu_to_le64(location);
836 	payload->checksum[0] = cpu_to_le32(checksum1);
837 	if (checksum2_valid)
838 		payload->checksum[1] = cpu_to_le32(checksum2);
839 
840 	io->meta_offset += sizeof(struct r5l_payload_data_parity) +
841 		sizeof(__le32) * (1 + !!checksum2_valid);
842 }
843 
r5l_append_payload_page(struct r5l_log * log,struct page * page)844 static void r5l_append_payload_page(struct r5l_log *log, struct page *page)
845 {
846 	struct r5l_io_unit *io = log->current_io;
847 
848 	if (io->need_split_bio) {
849 		BUG_ON(io->split_bio);
850 		io->split_bio = io->current_bio;
851 		io->current_bio = r5l_bio_alloc(log);
852 		bio_chain(io->current_bio, io->split_bio);
853 		io->need_split_bio = false;
854 	}
855 
856 	if (!bio_add_page(io->current_bio, page, PAGE_SIZE, 0))
857 		BUG();
858 
859 	r5_reserve_log_entry(log, io);
860 }
861 
r5l_append_flush_payload(struct r5l_log * log,sector_t sect)862 static void r5l_append_flush_payload(struct r5l_log *log, sector_t sect)
863 {
864 	struct mddev *mddev = log->rdev->mddev;
865 	struct r5conf *conf = mddev->private;
866 	struct r5l_io_unit *io;
867 	struct r5l_payload_flush *payload;
868 	int meta_size;
869 
870 	/*
871 	 * payload_flush requires extra writes to the journal.
872 	 * To avoid handling the extra IO in quiesce, just skip
873 	 * flush_payload
874 	 */
875 	if (conf->quiesce)
876 		return;
877 
878 	mutex_lock(&log->io_mutex);
879 	meta_size = sizeof(struct r5l_payload_flush) + sizeof(__le64);
880 
881 	if (r5l_get_meta(log, meta_size)) {
882 		mutex_unlock(&log->io_mutex);
883 		return;
884 	}
885 
886 	/* current implementation is one stripe per flush payload */
887 	io = log->current_io;
888 	payload = page_address(io->meta_page) + io->meta_offset;
889 	payload->header.type = cpu_to_le16(R5LOG_PAYLOAD_FLUSH);
890 	payload->header.flags = cpu_to_le16(0);
891 	payload->size = cpu_to_le32(sizeof(__le64));
892 	payload->flush_stripes[0] = cpu_to_le64(sect);
893 	io->meta_offset += meta_size;
894 	/* multiple flush payloads count as one pending_stripe */
895 	if (!io->has_flush_payload) {
896 		io->has_flush_payload = 1;
897 		atomic_inc(&io->pending_stripe);
898 	}
899 	mutex_unlock(&log->io_mutex);
900 }
901 
r5l_log_stripe(struct r5l_log * log,struct stripe_head * sh,int data_pages,int parity_pages)902 static int r5l_log_stripe(struct r5l_log *log, struct stripe_head *sh,
903 			   int data_pages, int parity_pages)
904 {
905 	int i;
906 	int meta_size;
907 	int ret;
908 	struct r5l_io_unit *io;
909 
910 	meta_size =
911 		((sizeof(struct r5l_payload_data_parity) + sizeof(__le32))
912 		 * data_pages) +
913 		sizeof(struct r5l_payload_data_parity) +
914 		sizeof(__le32) * parity_pages;
915 
916 	ret = r5l_get_meta(log, meta_size);
917 	if (ret)
918 		return ret;
919 
920 	io = log->current_io;
921 
922 	if (test_and_clear_bit(STRIPE_R5C_PREFLUSH, &sh->state))
923 		io->has_flush = 1;
924 
925 	for (i = 0; i < sh->disks; i++) {
926 		if (!test_bit(R5_Wantwrite, &sh->dev[i].flags) ||
927 		    test_bit(R5_InJournal, &sh->dev[i].flags))
928 			continue;
929 		if (i == sh->pd_idx || i == sh->qd_idx)
930 			continue;
931 		if (test_bit(R5_WantFUA, &sh->dev[i].flags) &&
932 		    log->r5c_journal_mode == R5C_JOURNAL_MODE_WRITE_BACK) {
933 			io->has_fua = 1;
934 			/*
935 			 * we need to flush journal to make sure recovery can
936 			 * reach the data with fua flag
937 			 */
938 			io->has_flush = 1;
939 		}
940 		r5l_append_payload_meta(log, R5LOG_PAYLOAD_DATA,
941 					raid5_compute_blocknr(sh, i, 0),
942 					sh->dev[i].log_checksum, 0, false);
943 		r5l_append_payload_page(log, sh->dev[i].page);
944 	}
945 
946 	if (parity_pages == 2) {
947 		r5l_append_payload_meta(log, R5LOG_PAYLOAD_PARITY,
948 					sh->sector, sh->dev[sh->pd_idx].log_checksum,
949 					sh->dev[sh->qd_idx].log_checksum, true);
950 		r5l_append_payload_page(log, sh->dev[sh->pd_idx].page);
951 		r5l_append_payload_page(log, sh->dev[sh->qd_idx].page);
952 	} else if (parity_pages == 1) {
953 		r5l_append_payload_meta(log, R5LOG_PAYLOAD_PARITY,
954 					sh->sector, sh->dev[sh->pd_idx].log_checksum,
955 					0, false);
956 		r5l_append_payload_page(log, sh->dev[sh->pd_idx].page);
957 	} else  /* Just writing data, not parity, in caching phase */
958 		BUG_ON(parity_pages != 0);
959 
960 	list_add_tail(&sh->log_list, &io->stripe_list);
961 	atomic_inc(&io->pending_stripe);
962 	sh->log_io = io;
963 
964 	if (log->r5c_journal_mode == R5C_JOURNAL_MODE_WRITE_THROUGH)
965 		return 0;
966 
967 	if (sh->log_start == MaxSector) {
968 		BUG_ON(!list_empty(&sh->r5c));
969 		sh->log_start = io->log_start;
970 		spin_lock_irq(&log->stripe_in_journal_lock);
971 		list_add_tail(&sh->r5c,
972 			      &log->stripe_in_journal_list);
973 		spin_unlock_irq(&log->stripe_in_journal_lock);
974 		atomic_inc(&log->stripe_in_journal_count);
975 	}
976 	return 0;
977 }
978 
979 /* add stripe to no_space_stripes, and then wake up reclaim */
r5l_add_no_space_stripe(struct r5l_log * log,struct stripe_head * sh)980 static inline void r5l_add_no_space_stripe(struct r5l_log *log,
981 					   struct stripe_head *sh)
982 {
983 	spin_lock(&log->no_space_stripes_lock);
984 	list_add_tail(&sh->log_list, &log->no_space_stripes);
985 	spin_unlock(&log->no_space_stripes_lock);
986 }
987 
988 /*
989  * running in raid5d, where reclaim could wait for raid5d too (when it flushes
990  * data from log to raid disks), so we shouldn't wait for reclaim here
991  */
r5l_write_stripe(struct r5l_log * log,struct stripe_head * sh)992 int r5l_write_stripe(struct r5l_log *log, struct stripe_head *sh)
993 {
994 	struct r5conf *conf = sh->raid_conf;
995 	int write_disks = 0;
996 	int data_pages, parity_pages;
997 	int reserve;
998 	int i;
999 	int ret = 0;
1000 	bool wake_reclaim = false;
1001 
1002 	if (!log)
1003 		return -EAGAIN;
1004 	/* Don't support stripe batch */
1005 	if (sh->log_io || !test_bit(R5_Wantwrite, &sh->dev[sh->pd_idx].flags) ||
1006 	    test_bit(STRIPE_SYNCING, &sh->state)) {
1007 		/* the stripe is written to log, we start writing it to raid */
1008 		clear_bit(STRIPE_LOG_TRAPPED, &sh->state);
1009 		return -EAGAIN;
1010 	}
1011 
1012 	WARN_ON(test_bit(STRIPE_R5C_CACHING, &sh->state));
1013 
1014 	for (i = 0; i < sh->disks; i++) {
1015 		void *addr;
1016 
1017 		if (!test_bit(R5_Wantwrite, &sh->dev[i].flags) ||
1018 		    test_bit(R5_InJournal, &sh->dev[i].flags))
1019 			continue;
1020 
1021 		write_disks++;
1022 		/* checksum is already calculated in last run */
1023 		if (test_bit(STRIPE_LOG_TRAPPED, &sh->state))
1024 			continue;
1025 		addr = kmap_atomic(sh->dev[i].page);
1026 		sh->dev[i].log_checksum = crc32c_le(log->uuid_checksum,
1027 						    addr, PAGE_SIZE);
1028 		kunmap_atomic(addr);
1029 	}
1030 	parity_pages = 1 + !!(sh->qd_idx >= 0);
1031 	data_pages = write_disks - parity_pages;
1032 
1033 	set_bit(STRIPE_LOG_TRAPPED, &sh->state);
1034 	/*
1035 	 * The stripe must enter state machine again to finish the write, so
1036 	 * don't delay.
1037 	 */
1038 	clear_bit(STRIPE_DELAYED, &sh->state);
1039 	atomic_inc(&sh->count);
1040 
1041 	mutex_lock(&log->io_mutex);
1042 	/* meta + data */
1043 	reserve = (1 + write_disks) << (PAGE_SHIFT - 9);
1044 
1045 	if (log->r5c_journal_mode == R5C_JOURNAL_MODE_WRITE_THROUGH) {
1046 		if (!r5l_has_free_space(log, reserve)) {
1047 			r5l_add_no_space_stripe(log, sh);
1048 			wake_reclaim = true;
1049 		} else {
1050 			ret = r5l_log_stripe(log, sh, data_pages, parity_pages);
1051 			if (ret) {
1052 				spin_lock_irq(&log->io_list_lock);
1053 				list_add_tail(&sh->log_list,
1054 					      &log->no_mem_stripes);
1055 				spin_unlock_irq(&log->io_list_lock);
1056 			}
1057 		}
1058 	} else {  /* R5C_JOURNAL_MODE_WRITE_BACK */
1059 		/*
1060 		 * log space critical, do not process stripes that are
1061 		 * not in cache yet (sh->log_start == MaxSector).
1062 		 */
1063 		if (test_bit(R5C_LOG_CRITICAL, &conf->cache_state) &&
1064 		    sh->log_start == MaxSector) {
1065 			r5l_add_no_space_stripe(log, sh);
1066 			wake_reclaim = true;
1067 			reserve = 0;
1068 		} else if (!r5l_has_free_space(log, reserve)) {
1069 			if (sh->log_start == log->last_checkpoint)
1070 				BUG();
1071 			else
1072 				r5l_add_no_space_stripe(log, sh);
1073 		} else {
1074 			ret = r5l_log_stripe(log, sh, data_pages, parity_pages);
1075 			if (ret) {
1076 				spin_lock_irq(&log->io_list_lock);
1077 				list_add_tail(&sh->log_list,
1078 					      &log->no_mem_stripes);
1079 				spin_unlock_irq(&log->io_list_lock);
1080 			}
1081 		}
1082 	}
1083 
1084 	mutex_unlock(&log->io_mutex);
1085 	if (wake_reclaim)
1086 		r5l_wake_reclaim(log, reserve);
1087 	return 0;
1088 }
1089 
r5l_write_stripe_run(struct r5l_log * log)1090 void r5l_write_stripe_run(struct r5l_log *log)
1091 {
1092 	if (!log)
1093 		return;
1094 	mutex_lock(&log->io_mutex);
1095 	r5l_submit_current_io(log);
1096 	mutex_unlock(&log->io_mutex);
1097 }
1098 
r5l_handle_flush_request(struct r5l_log * log,struct bio * bio)1099 int r5l_handle_flush_request(struct r5l_log *log, struct bio *bio)
1100 {
1101 	if (log->r5c_journal_mode == R5C_JOURNAL_MODE_WRITE_THROUGH) {
1102 		/*
1103 		 * in write through (journal only)
1104 		 * we flush log disk cache first, then write stripe data to
1105 		 * raid disks. So if bio is finished, the log disk cache is
1106 		 * flushed already. The recovery guarantees we can recovery
1107 		 * the bio from log disk, so we don't need to flush again
1108 		 */
1109 		if (bio->bi_iter.bi_size == 0) {
1110 			bio_endio(bio);
1111 			return 0;
1112 		}
1113 		bio->bi_opf &= ~REQ_PREFLUSH;
1114 	} else {
1115 		/* write back (with cache) */
1116 		if (bio->bi_iter.bi_size == 0) {
1117 			mutex_lock(&log->io_mutex);
1118 			r5l_get_meta(log, 0);
1119 			bio_list_add(&log->current_io->flush_barriers, bio);
1120 			log->current_io->has_flush = 1;
1121 			log->current_io->has_null_flush = 1;
1122 			atomic_inc(&log->current_io->pending_stripe);
1123 			r5l_submit_current_io(log);
1124 			mutex_unlock(&log->io_mutex);
1125 			return 0;
1126 		}
1127 	}
1128 	return -EAGAIN;
1129 }
1130 
1131 /* This will run after log space is reclaimed */
r5l_run_no_space_stripes(struct r5l_log * log)1132 static void r5l_run_no_space_stripes(struct r5l_log *log)
1133 {
1134 	struct stripe_head *sh;
1135 
1136 	spin_lock(&log->no_space_stripes_lock);
1137 	while (!list_empty(&log->no_space_stripes)) {
1138 		sh = list_first_entry(&log->no_space_stripes,
1139 				      struct stripe_head, log_list);
1140 		list_del_init(&sh->log_list);
1141 		set_bit(STRIPE_HANDLE, &sh->state);
1142 		raid5_release_stripe(sh);
1143 	}
1144 	spin_unlock(&log->no_space_stripes_lock);
1145 }
1146 
1147 /*
1148  * calculate new last_checkpoint
1149  * for write through mode, returns log->next_checkpoint
1150  * for write back, returns log_start of first sh in stripe_in_journal_list
1151  */
r5c_calculate_new_cp(struct r5conf * conf)1152 static sector_t r5c_calculate_new_cp(struct r5conf *conf)
1153 {
1154 	struct stripe_head *sh;
1155 	struct r5l_log *log = conf->log;
1156 	sector_t new_cp;
1157 	unsigned long flags;
1158 
1159 	if (log->r5c_journal_mode == R5C_JOURNAL_MODE_WRITE_THROUGH)
1160 		return log->next_checkpoint;
1161 
1162 	spin_lock_irqsave(&log->stripe_in_journal_lock, flags);
1163 	if (list_empty(&conf->log->stripe_in_journal_list)) {
1164 		/* all stripes flushed */
1165 		spin_unlock_irqrestore(&log->stripe_in_journal_lock, flags);
1166 		return log->next_checkpoint;
1167 	}
1168 	sh = list_first_entry(&conf->log->stripe_in_journal_list,
1169 			      struct stripe_head, r5c);
1170 	new_cp = sh->log_start;
1171 	spin_unlock_irqrestore(&log->stripe_in_journal_lock, flags);
1172 	return new_cp;
1173 }
1174 
r5l_reclaimable_space(struct r5l_log * log)1175 static sector_t r5l_reclaimable_space(struct r5l_log *log)
1176 {
1177 	struct r5conf *conf = log->rdev->mddev->private;
1178 
1179 	return r5l_ring_distance(log, log->last_checkpoint,
1180 				 r5c_calculate_new_cp(conf));
1181 }
1182 
r5l_run_no_mem_stripe(struct r5l_log * log)1183 static void r5l_run_no_mem_stripe(struct r5l_log *log)
1184 {
1185 	struct stripe_head *sh;
1186 
1187 	lockdep_assert_held(&log->io_list_lock);
1188 
1189 	if (!list_empty(&log->no_mem_stripes)) {
1190 		sh = list_first_entry(&log->no_mem_stripes,
1191 				      struct stripe_head, log_list);
1192 		list_del_init(&sh->log_list);
1193 		set_bit(STRIPE_HANDLE, &sh->state);
1194 		raid5_release_stripe(sh);
1195 	}
1196 }
1197 
r5l_complete_finished_ios(struct r5l_log * log)1198 static bool r5l_complete_finished_ios(struct r5l_log *log)
1199 {
1200 	struct r5l_io_unit *io, *next;
1201 	bool found = false;
1202 
1203 	lockdep_assert_held(&log->io_list_lock);
1204 
1205 	list_for_each_entry_safe(io, next, &log->finished_ios, log_sibling) {
1206 		/* don't change list order */
1207 		if (io->state < IO_UNIT_STRIPE_END)
1208 			break;
1209 
1210 		log->next_checkpoint = io->log_start;
1211 
1212 		list_del(&io->log_sibling);
1213 		mempool_free(io, &log->io_pool);
1214 		r5l_run_no_mem_stripe(log);
1215 
1216 		found = true;
1217 	}
1218 
1219 	return found;
1220 }
1221 
__r5l_stripe_write_finished(struct r5l_io_unit * io)1222 static void __r5l_stripe_write_finished(struct r5l_io_unit *io)
1223 {
1224 	struct r5l_log *log = io->log;
1225 	struct r5conf *conf = log->rdev->mddev->private;
1226 	unsigned long flags;
1227 
1228 	spin_lock_irqsave(&log->io_list_lock, flags);
1229 	__r5l_set_io_unit_state(io, IO_UNIT_STRIPE_END);
1230 
1231 	if (!r5l_complete_finished_ios(log)) {
1232 		spin_unlock_irqrestore(&log->io_list_lock, flags);
1233 		return;
1234 	}
1235 
1236 	if (r5l_reclaimable_space(log) > log->max_free_space ||
1237 	    test_bit(R5C_LOG_TIGHT, &conf->cache_state))
1238 		r5l_wake_reclaim(log, 0);
1239 
1240 	spin_unlock_irqrestore(&log->io_list_lock, flags);
1241 	wake_up(&log->iounit_wait);
1242 }
1243 
r5l_stripe_write_finished(struct stripe_head * sh)1244 void r5l_stripe_write_finished(struct stripe_head *sh)
1245 {
1246 	struct r5l_io_unit *io;
1247 
1248 	io = sh->log_io;
1249 	sh->log_io = NULL;
1250 
1251 	if (io && atomic_dec_and_test(&io->pending_stripe))
1252 		__r5l_stripe_write_finished(io);
1253 }
1254 
r5l_log_flush_endio(struct bio * bio)1255 static void r5l_log_flush_endio(struct bio *bio)
1256 {
1257 	struct r5l_log *log = container_of(bio, struct r5l_log,
1258 		flush_bio);
1259 	unsigned long flags;
1260 	struct r5l_io_unit *io;
1261 
1262 	if (bio->bi_status)
1263 		md_error(log->rdev->mddev, log->rdev);
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_reset(&log->flush_bio);
1306 	bio_set_dev(&log->flush_bio, log->rdev->bdev);
1307 	log->flush_bio.bi_end_io = r5l_log_flush_endio;
1308 	log->flush_bio.bi_opf = REQ_OP_WRITE | REQ_PREFLUSH;
1309 	submit_bio(&log->flush_bio);
1310 }
1311 
1312 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)1313 static void r5l_write_super_and_discard_space(struct r5l_log *log,
1314 	sector_t end)
1315 {
1316 	struct block_device *bdev = log->rdev->bdev;
1317 	struct mddev *mddev;
1318 
1319 	r5l_write_super(log, end);
1320 
1321 	if (!blk_queue_discard(bdev_get_queue(bdev)))
1322 		return;
1323 
1324 	mddev = log->rdev->mddev;
1325 	/*
1326 	 * Discard could zero data, so before discard we must make sure
1327 	 * superblock is updated to new log tail. Updating superblock (either
1328 	 * directly call md_update_sb() or depend on md thread) must hold
1329 	 * reconfig mutex. On the other hand, raid5_quiesce is called with
1330 	 * reconfig_mutex hold. The first step of raid5_quiesce() is waitting
1331 	 * for all IO finish, hence waitting for reclaim thread, while reclaim
1332 	 * thread is calling this function and waitting for reconfig mutex. So
1333 	 * there is a deadlock. We workaround this issue with a trylock.
1334 	 * FIXME: we could miss discard if we can't take reconfig mutex
1335 	 */
1336 	set_mask_bits(&mddev->sb_flags, 0,
1337 		BIT(MD_SB_CHANGE_DEVS) | BIT(MD_SB_CHANGE_PENDING));
1338 	if (!mddev_trylock(mddev))
1339 		return;
1340 	md_update_sb(mddev, 1);
1341 	mddev_unlock(mddev);
1342 
1343 	/* discard IO error really doesn't matter, ignore it */
1344 	if (log->last_checkpoint < end) {
1345 		blkdev_issue_discard(bdev,
1346 				log->last_checkpoint + log->rdev->data_offset,
1347 				end - log->last_checkpoint, GFP_NOIO, 0);
1348 	} else {
1349 		blkdev_issue_discard(bdev,
1350 				log->last_checkpoint + log->rdev->data_offset,
1351 				log->device_size - log->last_checkpoint,
1352 				GFP_NOIO, 0);
1353 		blkdev_issue_discard(bdev, log->rdev->data_offset, end,
1354 				GFP_NOIO, 0);
1355 	}
1356 }
1357 
1358 /*
1359  * r5c_flush_stripe moves stripe from cached list to handle_list. When called,
1360  * the stripe must be on r5c_cached_full_stripes or r5c_cached_partial_stripes.
1361  *
1362  * must hold conf->device_lock
1363  */
r5c_flush_stripe(struct r5conf * conf,struct stripe_head * sh)1364 static void r5c_flush_stripe(struct r5conf *conf, struct stripe_head *sh)
1365 {
1366 	BUG_ON(list_empty(&sh->lru));
1367 	BUG_ON(!test_bit(STRIPE_R5C_CACHING, &sh->state));
1368 	BUG_ON(test_bit(STRIPE_HANDLE, &sh->state));
1369 
1370 	/*
1371 	 * The stripe is not ON_RELEASE_LIST, so it is safe to call
1372 	 * raid5_release_stripe() while holding conf->device_lock
1373 	 */
1374 	BUG_ON(test_bit(STRIPE_ON_RELEASE_LIST, &sh->state));
1375 	lockdep_assert_held(&conf->device_lock);
1376 
1377 	list_del_init(&sh->lru);
1378 	atomic_inc(&sh->count);
1379 
1380 	set_bit(STRIPE_HANDLE, &sh->state);
1381 	atomic_inc(&conf->active_stripes);
1382 	r5c_make_stripe_write_out(sh);
1383 
1384 	if (test_bit(STRIPE_R5C_PARTIAL_STRIPE, &sh->state))
1385 		atomic_inc(&conf->r5c_flushing_partial_stripes);
1386 	else
1387 		atomic_inc(&conf->r5c_flushing_full_stripes);
1388 	raid5_release_stripe(sh);
1389 }
1390 
1391 /*
1392  * if num == 0, flush all full stripes
1393  * if num > 0, flush all full stripes. If less than num full stripes are
1394  *             flushed, flush some partial stripes until totally num stripes are
1395  *             flushed or there is no more cached stripes.
1396  */
r5c_flush_cache(struct r5conf * conf,int num)1397 void r5c_flush_cache(struct r5conf *conf, int num)
1398 {
1399 	int count;
1400 	struct stripe_head *sh, *next;
1401 
1402 	lockdep_assert_held(&conf->device_lock);
1403 	if (!conf->log)
1404 		return;
1405 
1406 	count = 0;
1407 	list_for_each_entry_safe(sh, next, &conf->r5c_full_stripe_list, lru) {
1408 		r5c_flush_stripe(conf, sh);
1409 		count++;
1410 	}
1411 
1412 	if (count >= num)
1413 		return;
1414 	list_for_each_entry_safe(sh, next,
1415 				 &conf->r5c_partial_stripe_list, lru) {
1416 		r5c_flush_stripe(conf, sh);
1417 		if (++count >= num)
1418 			break;
1419 	}
1420 }
1421 
r5c_do_reclaim(struct r5conf * conf)1422 static void r5c_do_reclaim(struct r5conf *conf)
1423 {
1424 	struct r5l_log *log = conf->log;
1425 	struct stripe_head *sh;
1426 	int count = 0;
1427 	unsigned long flags;
1428 	int total_cached;
1429 	int stripes_to_flush;
1430 	int flushing_partial, flushing_full;
1431 
1432 	if (!r5c_is_writeback(log))
1433 		return;
1434 
1435 	flushing_partial = atomic_read(&conf->r5c_flushing_partial_stripes);
1436 	flushing_full = atomic_read(&conf->r5c_flushing_full_stripes);
1437 	total_cached = atomic_read(&conf->r5c_cached_partial_stripes) +
1438 		atomic_read(&conf->r5c_cached_full_stripes) -
1439 		flushing_full - flushing_partial;
1440 
1441 	if (total_cached > conf->min_nr_stripes * 3 / 4 ||
1442 	    atomic_read(&conf->empty_inactive_list_nr) > 0)
1443 		/*
1444 		 * if stripe cache pressure high, flush all full stripes and
1445 		 * some partial stripes
1446 		 */
1447 		stripes_to_flush = R5C_RECLAIM_STRIPE_GROUP;
1448 	else if (total_cached > conf->min_nr_stripes * 1 / 2 ||
1449 		 atomic_read(&conf->r5c_cached_full_stripes) - flushing_full >
1450 		 R5C_FULL_STRIPE_FLUSH_BATCH(conf))
1451 		/*
1452 		 * if stripe cache pressure moderate, or if there is many full
1453 		 * stripes,flush all full stripes
1454 		 */
1455 		stripes_to_flush = 0;
1456 	else
1457 		/* no need to flush */
1458 		stripes_to_flush = -1;
1459 
1460 	if (stripes_to_flush >= 0) {
1461 		spin_lock_irqsave(&conf->device_lock, flags);
1462 		r5c_flush_cache(conf, stripes_to_flush);
1463 		spin_unlock_irqrestore(&conf->device_lock, flags);
1464 	}
1465 
1466 	/* if log space is tight, flush stripes on stripe_in_journal_list */
1467 	if (test_bit(R5C_LOG_TIGHT, &conf->cache_state)) {
1468 		spin_lock_irqsave(&log->stripe_in_journal_lock, flags);
1469 		spin_lock(&conf->device_lock);
1470 		list_for_each_entry(sh, &log->stripe_in_journal_list, r5c) {
1471 			/*
1472 			 * stripes on stripe_in_journal_list could be in any
1473 			 * state of the stripe_cache state machine. In this
1474 			 * case, we only want to flush stripe on
1475 			 * r5c_cached_full/partial_stripes. The following
1476 			 * condition makes sure the stripe is on one of the
1477 			 * two lists.
1478 			 */
1479 			if (!list_empty(&sh->lru) &&
1480 			    !test_bit(STRIPE_HANDLE, &sh->state) &&
1481 			    atomic_read(&sh->count) == 0) {
1482 				r5c_flush_stripe(conf, sh);
1483 				if (count++ >= R5C_RECLAIM_STRIPE_GROUP)
1484 					break;
1485 			}
1486 		}
1487 		spin_unlock(&conf->device_lock);
1488 		spin_unlock_irqrestore(&log->stripe_in_journal_lock, flags);
1489 	}
1490 
1491 	if (!test_bit(R5C_LOG_CRITICAL, &conf->cache_state))
1492 		r5l_run_no_space_stripes(log);
1493 
1494 	md_wakeup_thread(conf->mddev->thread);
1495 }
1496 
r5l_do_reclaim(struct r5l_log * log)1497 static void r5l_do_reclaim(struct r5l_log *log)
1498 {
1499 	struct r5conf *conf = log->rdev->mddev->private;
1500 	sector_t reclaim_target = xchg(&log->reclaim_target, 0);
1501 	sector_t reclaimable;
1502 	sector_t next_checkpoint;
1503 	bool write_super;
1504 
1505 	spin_lock_irq(&log->io_list_lock);
1506 	write_super = r5l_reclaimable_space(log) > log->max_free_space ||
1507 		reclaim_target != 0 || !list_empty(&log->no_space_stripes);
1508 	/*
1509 	 * move proper io_unit to reclaim list. We should not change the order.
1510 	 * reclaimable/unreclaimable io_unit can be mixed in the list, we
1511 	 * shouldn't reuse space of an unreclaimable io_unit
1512 	 */
1513 	while (1) {
1514 		reclaimable = r5l_reclaimable_space(log);
1515 		if (reclaimable >= reclaim_target ||
1516 		    (list_empty(&log->running_ios) &&
1517 		     list_empty(&log->io_end_ios) &&
1518 		     list_empty(&log->flushing_ios) &&
1519 		     list_empty(&log->finished_ios)))
1520 			break;
1521 
1522 		md_wakeup_thread(log->rdev->mddev->thread);
1523 		wait_event_lock_irq(log->iounit_wait,
1524 				    r5l_reclaimable_space(log) > reclaimable,
1525 				    log->io_list_lock);
1526 	}
1527 
1528 	next_checkpoint = r5c_calculate_new_cp(conf);
1529 	spin_unlock_irq(&log->io_list_lock);
1530 
1531 	if (reclaimable == 0 || !write_super)
1532 		return;
1533 
1534 	/*
1535 	 * write_super will flush cache of each raid disk. We must write super
1536 	 * here, because the log area might be reused soon and we don't want to
1537 	 * confuse recovery
1538 	 */
1539 	r5l_write_super_and_discard_space(log, next_checkpoint);
1540 
1541 	mutex_lock(&log->io_mutex);
1542 	log->last_checkpoint = next_checkpoint;
1543 	r5c_update_log_state(log);
1544 	mutex_unlock(&log->io_mutex);
1545 
1546 	r5l_run_no_space_stripes(log);
1547 }
1548 
r5l_reclaim_thread(struct md_thread * thread)1549 static void r5l_reclaim_thread(struct md_thread *thread)
1550 {
1551 	struct mddev *mddev = thread->mddev;
1552 	struct r5conf *conf = mddev->private;
1553 	struct r5l_log *log = conf->log;
1554 
1555 	if (!log)
1556 		return;
1557 	r5c_do_reclaim(conf);
1558 	r5l_do_reclaim(log);
1559 }
1560 
r5l_wake_reclaim(struct r5l_log * log,sector_t space)1561 void r5l_wake_reclaim(struct r5l_log *log, sector_t space)
1562 {
1563 	unsigned long target;
1564 	unsigned long new = (unsigned long)space; /* overflow in theory */
1565 
1566 	if (!log)
1567 		return;
1568 	do {
1569 		target = log->reclaim_target;
1570 		if (new < target)
1571 			return;
1572 	} while (cmpxchg(&log->reclaim_target, target, new) != target);
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;
1579 
1580 	if (quiesce) {
1581 		/* make sure r5l_write_super_and_discard_space exits */
1582 		mddev = log->rdev->mddev;
1583 		wake_up(&mddev->sb_wait);
1584 		kthread_park(log->reclaim_thread->tsk);
1585 		r5l_wake_reclaim(log, MaxSector);
1586 		r5l_do_reclaim(log);
1587 	} else
1588 		kthread_unpark(log->reclaim_thread->tsk);
1589 }
1590 
r5l_log_disk_error(struct r5conf * conf)1591 bool r5l_log_disk_error(struct r5conf *conf)
1592 {
1593 	struct r5l_log *log;
1594 	bool ret;
1595 	/* don't allow write if journal disk is missing */
1596 	rcu_read_lock();
1597 	log = rcu_dereference(conf->log);
1598 
1599 	if (!log)
1600 		ret = test_bit(MD_HAS_JOURNAL, &conf->mddev->flags);
1601 	else
1602 		ret = test_bit(Faulty, &log->rdev->flags);
1603 	rcu_read_unlock();
1604 	return ret;
1605 }
1606 
1607 #define R5L_RECOVERY_PAGE_POOL_SIZE 256
1608 
1609 struct r5l_recovery_ctx {
1610 	struct page *meta_page;		/* current meta */
1611 	sector_t meta_total_blocks;	/* total size of current meta and data */
1612 	sector_t pos;			/* recovery position */
1613 	u64 seq;			/* recovery position seq */
1614 	int data_parity_stripes;	/* number of data_parity stripes */
1615 	int data_only_stripes;		/* number of data_only stripes */
1616 	struct list_head cached_list;
1617 
1618 	/*
1619 	 * read ahead page pool (ra_pool)
1620 	 * in recovery, log is read sequentially. It is not efficient to
1621 	 * read every page with sync_page_io(). The read ahead page pool
1622 	 * reads multiple pages with one IO, so further log read can
1623 	 * just copy data from the pool.
1624 	 */
1625 	struct page *ra_pool[R5L_RECOVERY_PAGE_POOL_SIZE];
1626 	sector_t pool_offset;	/* offset of first page in the pool */
1627 	int total_pages;	/* total allocated pages */
1628 	int valid_pages;	/* pages with valid data */
1629 	struct bio *ra_bio;	/* bio to do the read ahead */
1630 };
1631 
r5l_recovery_allocate_ra_pool(struct r5l_log * log,struct r5l_recovery_ctx * ctx)1632 static int r5l_recovery_allocate_ra_pool(struct r5l_log *log,
1633 					    struct r5l_recovery_ctx *ctx)
1634 {
1635 	struct page *page;
1636 
1637 	ctx->ra_bio = bio_alloc_bioset(GFP_KERNEL, BIO_MAX_VECS, &log->bs);
1638 	if (!ctx->ra_bio)
1639 		return -ENOMEM;
1640 
1641 	ctx->valid_pages = 0;
1642 	ctx->total_pages = 0;
1643 	while (ctx->total_pages < R5L_RECOVERY_PAGE_POOL_SIZE) {
1644 		page = alloc_page(GFP_KERNEL);
1645 
1646 		if (!page)
1647 			break;
1648 		ctx->ra_pool[ctx->total_pages] = page;
1649 		ctx->total_pages += 1;
1650 	}
1651 
1652 	if (ctx->total_pages == 0) {
1653 		bio_put(ctx->ra_bio);
1654 		return -ENOMEM;
1655 	}
1656 
1657 	ctx->pool_offset = 0;
1658 	return 0;
1659 }
1660 
r5l_recovery_free_ra_pool(struct r5l_log * log,struct r5l_recovery_ctx * ctx)1661 static void r5l_recovery_free_ra_pool(struct r5l_log *log,
1662 					struct r5l_recovery_ctx *ctx)
1663 {
1664 	int i;
1665 
1666 	for (i = 0; i < ctx->total_pages; ++i)
1667 		put_page(ctx->ra_pool[i]);
1668 	bio_put(ctx->ra_bio);
1669 }
1670 
1671 /*
1672  * fetch ctx->valid_pages pages from offset
1673  * In normal cases, ctx->valid_pages == ctx->total_pages after the call.
1674  * However, if the offset is close to the end of the journal device,
1675  * ctx->valid_pages could be smaller than ctx->total_pages
1676  */
r5l_recovery_fetch_ra_pool(struct r5l_log * log,struct r5l_recovery_ctx * ctx,sector_t offset)1677 static int r5l_recovery_fetch_ra_pool(struct r5l_log *log,
1678 				      struct r5l_recovery_ctx *ctx,
1679 				      sector_t offset)
1680 {
1681 	bio_reset(ctx->ra_bio);
1682 	bio_set_dev(ctx->ra_bio, log->rdev->bdev);
1683 	bio_set_op_attrs(ctx->ra_bio, REQ_OP_READ, 0);
1684 	ctx->ra_bio->bi_iter.bi_sector = log->rdev->data_offset + offset;
1685 
1686 	ctx->valid_pages = 0;
1687 	ctx->pool_offset = offset;
1688 
1689 	while (ctx->valid_pages < ctx->total_pages) {
1690 		bio_add_page(ctx->ra_bio,
1691 			     ctx->ra_pool[ctx->valid_pages], PAGE_SIZE, 0);
1692 		ctx->valid_pages += 1;
1693 
1694 		offset = r5l_ring_add(log, offset, BLOCK_SECTORS);
1695 
1696 		if (offset == 0)  /* reached end of the device */
1697 			break;
1698 	}
1699 
1700 	return submit_bio_wait(ctx->ra_bio);
1701 }
1702 
1703 /*
1704  * try read a page from the read ahead page pool, if the page is not in the
1705  * pool, call r5l_recovery_fetch_ra_pool
1706  */
r5l_recovery_read_page(struct r5l_log * log,struct r5l_recovery_ctx * ctx,struct page * page,sector_t offset)1707 static int r5l_recovery_read_page(struct r5l_log *log,
1708 				  struct r5l_recovery_ctx *ctx,
1709 				  struct page *page,
1710 				  sector_t offset)
1711 {
1712 	int ret;
1713 
1714 	if (offset < ctx->pool_offset ||
1715 	    offset >= ctx->pool_offset + ctx->valid_pages * BLOCK_SECTORS) {
1716 		ret = r5l_recovery_fetch_ra_pool(log, ctx, offset);
1717 		if (ret)
1718 			return ret;
1719 	}
1720 
1721 	BUG_ON(offset < ctx->pool_offset ||
1722 	       offset >= ctx->pool_offset + ctx->valid_pages * BLOCK_SECTORS);
1723 
1724 	memcpy(page_address(page),
1725 	       page_address(ctx->ra_pool[(offset - ctx->pool_offset) >>
1726 					 BLOCK_SECTOR_SHIFT]),
1727 	       PAGE_SIZE);
1728 	return 0;
1729 }
1730 
r5l_recovery_read_meta_block(struct r5l_log * log,struct r5l_recovery_ctx * ctx)1731 static int r5l_recovery_read_meta_block(struct r5l_log *log,
1732 					struct r5l_recovery_ctx *ctx)
1733 {
1734 	struct page *page = ctx->meta_page;
1735 	struct r5l_meta_block *mb;
1736 	u32 crc, stored_crc;
1737 	int ret;
1738 
1739 	ret = r5l_recovery_read_page(log, ctx, page, ctx->pos);
1740 	if (ret != 0)
1741 		return ret;
1742 
1743 	mb = page_address(page);
1744 	stored_crc = le32_to_cpu(mb->checksum);
1745 	mb->checksum = 0;
1746 
1747 	if (le32_to_cpu(mb->magic) != R5LOG_MAGIC ||
1748 	    le64_to_cpu(mb->seq) != ctx->seq ||
1749 	    mb->version != R5LOG_VERSION ||
1750 	    le64_to_cpu(mb->position) != ctx->pos)
1751 		return -EINVAL;
1752 
1753 	crc = crc32c_le(log->uuid_checksum, mb, PAGE_SIZE);
1754 	if (stored_crc != crc)
1755 		return -EINVAL;
1756 
1757 	if (le32_to_cpu(mb->meta_size) > PAGE_SIZE)
1758 		return -EINVAL;
1759 
1760 	ctx->meta_total_blocks = BLOCK_SECTORS;
1761 
1762 	return 0;
1763 }
1764 
1765 static void
r5l_recovery_create_empty_meta_block(struct r5l_log * log,struct page * page,sector_t pos,u64 seq)1766 r5l_recovery_create_empty_meta_block(struct r5l_log *log,
1767 				     struct page *page,
1768 				     sector_t pos, u64 seq)
1769 {
1770 	struct r5l_meta_block *mb;
1771 
1772 	mb = page_address(page);
1773 	clear_page(mb);
1774 	mb->magic = cpu_to_le32(R5LOG_MAGIC);
1775 	mb->version = R5LOG_VERSION;
1776 	mb->meta_size = cpu_to_le32(sizeof(struct r5l_meta_block));
1777 	mb->seq = cpu_to_le64(seq);
1778 	mb->position = cpu_to_le64(pos);
1779 }
1780 
r5l_log_write_empty_meta_block(struct r5l_log * log,sector_t pos,u64 seq)1781 static int r5l_log_write_empty_meta_block(struct r5l_log *log, sector_t pos,
1782 					  u64 seq)
1783 {
1784 	struct page *page;
1785 	struct r5l_meta_block *mb;
1786 
1787 	page = alloc_page(GFP_KERNEL);
1788 	if (!page)
1789 		return -ENOMEM;
1790 	r5l_recovery_create_empty_meta_block(log, page, pos, seq);
1791 	mb = page_address(page);
1792 	mb->checksum = cpu_to_le32(crc32c_le(log->uuid_checksum,
1793 					     mb, PAGE_SIZE));
1794 	if (!sync_page_io(log->rdev, pos, PAGE_SIZE, page, REQ_OP_WRITE,
1795 			  REQ_SYNC | REQ_FUA, false)) {
1796 		__free_page(page);
1797 		return -EIO;
1798 	}
1799 	__free_page(page);
1800 	return 0;
1801 }
1802 
1803 /*
1804  * r5l_recovery_load_data and r5l_recovery_load_parity uses flag R5_Wantwrite
1805  * to mark valid (potentially not flushed) data in the journal.
1806  *
1807  * We already verified checksum in r5l_recovery_verify_data_checksum_for_mb,
1808  * so there should not be any mismatch here.
1809  */
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)1810 static void r5l_recovery_load_data(struct r5l_log *log,
1811 				   struct stripe_head *sh,
1812 				   struct r5l_recovery_ctx *ctx,
1813 				   struct r5l_payload_data_parity *payload,
1814 				   sector_t log_offset)
1815 {
1816 	struct mddev *mddev = log->rdev->mddev;
1817 	struct r5conf *conf = mddev->private;
1818 	int dd_idx;
1819 
1820 	raid5_compute_sector(conf,
1821 			     le64_to_cpu(payload->location), 0,
1822 			     &dd_idx, sh);
1823 	r5l_recovery_read_page(log, ctx, sh->dev[dd_idx].page, log_offset);
1824 	sh->dev[dd_idx].log_checksum =
1825 		le32_to_cpu(payload->checksum[0]);
1826 	ctx->meta_total_blocks += BLOCK_SECTORS;
1827 
1828 	set_bit(R5_Wantwrite, &sh->dev[dd_idx].flags);
1829 	set_bit(STRIPE_R5C_CACHING, &sh->state);
1830 }
1831 
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)1832 static void r5l_recovery_load_parity(struct r5l_log *log,
1833 				     struct stripe_head *sh,
1834 				     struct r5l_recovery_ctx *ctx,
1835 				     struct r5l_payload_data_parity *payload,
1836 				     sector_t log_offset)
1837 {
1838 	struct mddev *mddev = log->rdev->mddev;
1839 	struct r5conf *conf = mddev->private;
1840 
1841 	ctx->meta_total_blocks += BLOCK_SECTORS * conf->max_degraded;
1842 	r5l_recovery_read_page(log, ctx, sh->dev[sh->pd_idx].page, log_offset);
1843 	sh->dev[sh->pd_idx].log_checksum =
1844 		le32_to_cpu(payload->checksum[0]);
1845 	set_bit(R5_Wantwrite, &sh->dev[sh->pd_idx].flags);
1846 
1847 	if (sh->qd_idx >= 0) {
1848 		r5l_recovery_read_page(
1849 			log, ctx, sh->dev[sh->qd_idx].page,
1850 			r5l_ring_add(log, log_offset, BLOCK_SECTORS));
1851 		sh->dev[sh->qd_idx].log_checksum =
1852 			le32_to_cpu(payload->checksum[1]);
1853 		set_bit(R5_Wantwrite, &sh->dev[sh->qd_idx].flags);
1854 	}
1855 	clear_bit(STRIPE_R5C_CACHING, &sh->state);
1856 }
1857 
r5l_recovery_reset_stripe(struct stripe_head * sh)1858 static void r5l_recovery_reset_stripe(struct stripe_head *sh)
1859 {
1860 	int i;
1861 
1862 	sh->state = 0;
1863 	sh->log_start = MaxSector;
1864 	for (i = sh->disks; i--; )
1865 		sh->dev[i].flags = 0;
1866 }
1867 
1868 static void
r5l_recovery_replay_one_stripe(struct r5conf * conf,struct stripe_head * sh,struct r5l_recovery_ctx * ctx)1869 r5l_recovery_replay_one_stripe(struct r5conf *conf,
1870 			       struct stripe_head *sh,
1871 			       struct r5l_recovery_ctx *ctx)
1872 {
1873 	struct md_rdev *rdev, *rrdev;
1874 	int disk_index;
1875 	int data_count = 0;
1876 
1877 	for (disk_index = 0; disk_index < sh->disks; disk_index++) {
1878 		if (!test_bit(R5_Wantwrite, &sh->dev[disk_index].flags))
1879 			continue;
1880 		if (disk_index == sh->qd_idx || disk_index == sh->pd_idx)
1881 			continue;
1882 		data_count++;
1883 	}
1884 
1885 	/*
1886 	 * stripes that only have parity must have been flushed
1887 	 * before the crash that we are now recovering from, so
1888 	 * there is nothing more to recovery.
1889 	 */
1890 	if (data_count == 0)
1891 		goto out;
1892 
1893 	for (disk_index = 0; disk_index < sh->disks; disk_index++) {
1894 		if (!test_bit(R5_Wantwrite, &sh->dev[disk_index].flags))
1895 			continue;
1896 
1897 		/* in case device is broken */
1898 		rcu_read_lock();
1899 		rdev = rcu_dereference(conf->disks[disk_index].rdev);
1900 		if (rdev) {
1901 			atomic_inc(&rdev->nr_pending);
1902 			rcu_read_unlock();
1903 			sync_page_io(rdev, sh->sector, PAGE_SIZE,
1904 				     sh->dev[disk_index].page, REQ_OP_WRITE, 0,
1905 				     false);
1906 			rdev_dec_pending(rdev, rdev->mddev);
1907 			rcu_read_lock();
1908 		}
1909 		rrdev = rcu_dereference(conf->disks[disk_index].replacement);
1910 		if (rrdev) {
1911 			atomic_inc(&rrdev->nr_pending);
1912 			rcu_read_unlock();
1913 			sync_page_io(rrdev, sh->sector, PAGE_SIZE,
1914 				     sh->dev[disk_index].page, REQ_OP_WRITE, 0,
1915 				     false);
1916 			rdev_dec_pending(rrdev, rrdev->mddev);
1917 			rcu_read_lock();
1918 		}
1919 		rcu_read_unlock();
1920 	}
1921 	ctx->data_parity_stripes++;
1922 out:
1923 	r5l_recovery_reset_stripe(sh);
1924 }
1925 
1926 static struct stripe_head *
r5c_recovery_alloc_stripe(struct r5conf * conf,sector_t stripe_sect,int noblock)1927 r5c_recovery_alloc_stripe(
1928 		struct r5conf *conf,
1929 		sector_t stripe_sect,
1930 		int noblock)
1931 {
1932 	struct stripe_head *sh;
1933 
1934 	sh = raid5_get_active_stripe(conf, stripe_sect, 0, noblock, 0);
1935 	if (!sh)
1936 		return NULL;  /* no more stripe available */
1937 
1938 	r5l_recovery_reset_stripe(sh);
1939 
1940 	return sh;
1941 }
1942 
1943 static struct stripe_head *
r5c_recovery_lookup_stripe(struct list_head * list,sector_t sect)1944 r5c_recovery_lookup_stripe(struct list_head *list, sector_t sect)
1945 {
1946 	struct stripe_head *sh;
1947 
1948 	list_for_each_entry(sh, list, lru)
1949 		if (sh->sector == sect)
1950 			return sh;
1951 	return NULL;
1952 }
1953 
1954 static void
r5c_recovery_drop_stripes(struct list_head * cached_stripe_list,struct r5l_recovery_ctx * ctx)1955 r5c_recovery_drop_stripes(struct list_head *cached_stripe_list,
1956 			  struct r5l_recovery_ctx *ctx)
1957 {
1958 	struct stripe_head *sh, *next;
1959 
1960 	list_for_each_entry_safe(sh, next, cached_stripe_list, lru) {
1961 		r5l_recovery_reset_stripe(sh);
1962 		list_del_init(&sh->lru);
1963 		raid5_release_stripe(sh);
1964 	}
1965 }
1966 
1967 static void
r5c_recovery_replay_stripes(struct list_head * cached_stripe_list,struct r5l_recovery_ctx * ctx)1968 r5c_recovery_replay_stripes(struct list_head *cached_stripe_list,
1969 			    struct r5l_recovery_ctx *ctx)
1970 {
1971 	struct stripe_head *sh, *next;
1972 
1973 	list_for_each_entry_safe(sh, next, cached_stripe_list, lru)
1974 		if (!test_bit(STRIPE_R5C_CACHING, &sh->state)) {
1975 			r5l_recovery_replay_one_stripe(sh->raid_conf, sh, ctx);
1976 			list_del_init(&sh->lru);
1977 			raid5_release_stripe(sh);
1978 		}
1979 }
1980 
1981 /* if matches return 0; otherwise return -EINVAL */
1982 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)1983 r5l_recovery_verify_data_checksum(struct r5l_log *log,
1984 				  struct r5l_recovery_ctx *ctx,
1985 				  struct page *page,
1986 				  sector_t log_offset, __le32 log_checksum)
1987 {
1988 	void *addr;
1989 	u32 checksum;
1990 
1991 	r5l_recovery_read_page(log, ctx, page, log_offset);
1992 	addr = kmap_atomic(page);
1993 	checksum = crc32c_le(log->uuid_checksum, addr, PAGE_SIZE);
1994 	kunmap_atomic(addr);
1995 	return (le32_to_cpu(log_checksum) == checksum) ? 0 : -EINVAL;
1996 }
1997 
1998 /*
1999  * before loading data to stripe cache, we need verify checksum for all data,
2000  * if there is mismatch for any data page, we drop all data in the mata block
2001  */
2002 static int
r5l_recovery_verify_data_checksum_for_mb(struct r5l_log * log,struct r5l_recovery_ctx * ctx)2003 r5l_recovery_verify_data_checksum_for_mb(struct r5l_log *log,
2004 					 struct r5l_recovery_ctx *ctx)
2005 {
2006 	struct mddev *mddev = log->rdev->mddev;
2007 	struct r5conf *conf = mddev->private;
2008 	struct r5l_meta_block *mb = page_address(ctx->meta_page);
2009 	sector_t mb_offset = sizeof(struct r5l_meta_block);
2010 	sector_t log_offset = r5l_ring_add(log, ctx->pos, BLOCK_SECTORS);
2011 	struct page *page;
2012 	struct r5l_payload_data_parity *payload;
2013 	struct r5l_payload_flush *payload_flush;
2014 
2015 	page = alloc_page(GFP_KERNEL);
2016 	if (!page)
2017 		return -ENOMEM;
2018 
2019 	while (mb_offset < le32_to_cpu(mb->meta_size)) {
2020 		payload = (void *)mb + mb_offset;
2021 		payload_flush = (void *)mb + mb_offset;
2022 
2023 		if (le16_to_cpu(payload->header.type) == R5LOG_PAYLOAD_DATA) {
2024 			if (r5l_recovery_verify_data_checksum(
2025 				    log, ctx, page, log_offset,
2026 				    payload->checksum[0]) < 0)
2027 				goto mismatch;
2028 		} else if (le16_to_cpu(payload->header.type) == R5LOG_PAYLOAD_PARITY) {
2029 			if (r5l_recovery_verify_data_checksum(
2030 				    log, ctx, page, log_offset,
2031 				    payload->checksum[0]) < 0)
2032 				goto mismatch;
2033 			if (conf->max_degraded == 2 && /* q for RAID 6 */
2034 			    r5l_recovery_verify_data_checksum(
2035 				    log, ctx, page,
2036 				    r5l_ring_add(log, log_offset,
2037 						 BLOCK_SECTORS),
2038 				    payload->checksum[1]) < 0)
2039 				goto mismatch;
2040 		} else if (le16_to_cpu(payload->header.type) == R5LOG_PAYLOAD_FLUSH) {
2041 			/* nothing to do for R5LOG_PAYLOAD_FLUSH here */
2042 		} else /* not R5LOG_PAYLOAD_DATA/PARITY/FLUSH */
2043 			goto mismatch;
2044 
2045 		if (le16_to_cpu(payload->header.type) == R5LOG_PAYLOAD_FLUSH) {
2046 			mb_offset += sizeof(struct r5l_payload_flush) +
2047 				le32_to_cpu(payload_flush->size);
2048 		} else {
2049 			/* DATA or PARITY payload */
2050 			log_offset = r5l_ring_add(log, log_offset,
2051 						  le32_to_cpu(payload->size));
2052 			mb_offset += sizeof(struct r5l_payload_data_parity) +
2053 				sizeof(__le32) *
2054 				(le32_to_cpu(payload->size) >> (PAGE_SHIFT - 9));
2055 		}
2056 
2057 	}
2058 
2059 	put_page(page);
2060 	return 0;
2061 
2062 mismatch:
2063 	put_page(page);
2064 	return -EINVAL;
2065 }
2066 
2067 /*
2068  * Analyze all data/parity pages in one meta block
2069  * Returns:
2070  * 0 for success
2071  * -EINVAL for unknown playload type
2072  * -EAGAIN for checksum mismatch of data page
2073  * -ENOMEM for run out of memory (alloc_page failed or run out of stripes)
2074  */
2075 static int
r5c_recovery_analyze_meta_block(struct r5l_log * log,struct r5l_recovery_ctx * ctx,struct list_head * cached_stripe_list)2076 r5c_recovery_analyze_meta_block(struct r5l_log *log,
2077 				struct r5l_recovery_ctx *ctx,
2078 				struct list_head *cached_stripe_list)
2079 {
2080 	struct mddev *mddev = log->rdev->mddev;
2081 	struct r5conf *conf = mddev->private;
2082 	struct r5l_meta_block *mb;
2083 	struct r5l_payload_data_parity *payload;
2084 	struct r5l_payload_flush *payload_flush;
2085 	int mb_offset;
2086 	sector_t log_offset;
2087 	sector_t stripe_sect;
2088 	struct stripe_head *sh;
2089 	int ret;
2090 
2091 	/*
2092 	 * for mismatch in data blocks, we will drop all data in this mb, but
2093 	 * we will still read next mb for other data with FLUSH flag, as
2094 	 * io_unit could finish out of order.
2095 	 */
2096 	ret = r5l_recovery_verify_data_checksum_for_mb(log, ctx);
2097 	if (ret == -EINVAL)
2098 		return -EAGAIN;
2099 	else if (ret)
2100 		return ret;   /* -ENOMEM duo to alloc_page() failed */
2101 
2102 	mb = page_address(ctx->meta_page);
2103 	mb_offset = sizeof(struct r5l_meta_block);
2104 	log_offset = r5l_ring_add(log, ctx->pos, BLOCK_SECTORS);
2105 
2106 	while (mb_offset < le32_to_cpu(mb->meta_size)) {
2107 		int dd;
2108 
2109 		payload = (void *)mb + mb_offset;
2110 		payload_flush = (void *)mb + mb_offset;
2111 
2112 		if (le16_to_cpu(payload->header.type) == R5LOG_PAYLOAD_FLUSH) {
2113 			int i, count;
2114 
2115 			count = le32_to_cpu(payload_flush->size) / sizeof(__le64);
2116 			for (i = 0; i < count; ++i) {
2117 				stripe_sect = le64_to_cpu(payload_flush->flush_stripes[i]);
2118 				sh = r5c_recovery_lookup_stripe(cached_stripe_list,
2119 								stripe_sect);
2120 				if (sh) {
2121 					WARN_ON(test_bit(STRIPE_R5C_CACHING, &sh->state));
2122 					r5l_recovery_reset_stripe(sh);
2123 					list_del_init(&sh->lru);
2124 					raid5_release_stripe(sh);
2125 				}
2126 			}
2127 
2128 			mb_offset += sizeof(struct r5l_payload_flush) +
2129 				le32_to_cpu(payload_flush->size);
2130 			continue;
2131 		}
2132 
2133 		/* DATA or PARITY payload */
2134 		stripe_sect = (le16_to_cpu(payload->header.type) == R5LOG_PAYLOAD_DATA) ?
2135 			raid5_compute_sector(
2136 				conf, le64_to_cpu(payload->location), 0, &dd,
2137 				NULL)
2138 			: le64_to_cpu(payload->location);
2139 
2140 		sh = r5c_recovery_lookup_stripe(cached_stripe_list,
2141 						stripe_sect);
2142 
2143 		if (!sh) {
2144 			sh = r5c_recovery_alloc_stripe(conf, stripe_sect, 1);
2145 			/*
2146 			 * cannot get stripe from raid5_get_active_stripe
2147 			 * try replay some stripes
2148 			 */
2149 			if (!sh) {
2150 				r5c_recovery_replay_stripes(
2151 					cached_stripe_list, ctx);
2152 				sh = r5c_recovery_alloc_stripe(
2153 					conf, stripe_sect, 1);
2154 			}
2155 			if (!sh) {
2156 				int new_size = conf->min_nr_stripes * 2;
2157 				pr_debug("md/raid:%s: Increasing stripe cache size to %d to recovery data on journal.\n",
2158 					mdname(mddev),
2159 					new_size);
2160 				ret = raid5_set_cache_size(mddev, new_size);
2161 				if (conf->min_nr_stripes <= new_size / 2) {
2162 					pr_err("md/raid:%s: Cannot increase cache size, ret=%d, new_size=%d, min_nr_stripes=%d, max_nr_stripes=%d\n",
2163 						mdname(mddev),
2164 						ret,
2165 						new_size,
2166 						conf->min_nr_stripes,
2167 						conf->max_nr_stripes);
2168 					return -ENOMEM;
2169 				}
2170 				sh = r5c_recovery_alloc_stripe(
2171 					conf, stripe_sect, 0);
2172 			}
2173 			if (!sh) {
2174 				pr_err("md/raid:%s: Cannot get enough stripes due to memory pressure. Recovery failed.\n",
2175 					mdname(mddev));
2176 				return -ENOMEM;
2177 			}
2178 			list_add_tail(&sh->lru, cached_stripe_list);
2179 		}
2180 
2181 		if (le16_to_cpu(payload->header.type) == R5LOG_PAYLOAD_DATA) {
2182 			if (!test_bit(STRIPE_R5C_CACHING, &sh->state) &&
2183 			    test_bit(R5_Wantwrite, &sh->dev[sh->pd_idx].flags)) {
2184 				r5l_recovery_replay_one_stripe(conf, sh, ctx);
2185 				list_move_tail(&sh->lru, cached_stripe_list);
2186 			}
2187 			r5l_recovery_load_data(log, sh, ctx, payload,
2188 					       log_offset);
2189 		} else if (le16_to_cpu(payload->header.type) == R5LOG_PAYLOAD_PARITY)
2190 			r5l_recovery_load_parity(log, sh, ctx, payload,
2191 						 log_offset);
2192 		else
2193 			return -EINVAL;
2194 
2195 		log_offset = r5l_ring_add(log, log_offset,
2196 					  le32_to_cpu(payload->size));
2197 
2198 		mb_offset += sizeof(struct r5l_payload_data_parity) +
2199 			sizeof(__le32) *
2200 			(le32_to_cpu(payload->size) >> (PAGE_SHIFT - 9));
2201 	}
2202 
2203 	return 0;
2204 }
2205 
2206 /*
2207  * Load the stripe into cache. The stripe will be written out later by
2208  * the stripe cache state machine.
2209  */
r5c_recovery_load_one_stripe(struct r5l_log * log,struct stripe_head * sh)2210 static void r5c_recovery_load_one_stripe(struct r5l_log *log,
2211 					 struct stripe_head *sh)
2212 {
2213 	struct r5dev *dev;
2214 	int i;
2215 
2216 	for (i = sh->disks; i--; ) {
2217 		dev = sh->dev + i;
2218 		if (test_and_clear_bit(R5_Wantwrite, &dev->flags)) {
2219 			set_bit(R5_InJournal, &dev->flags);
2220 			set_bit(R5_UPTODATE, &dev->flags);
2221 		}
2222 	}
2223 }
2224 
2225 /*
2226  * Scan through the log for all to-be-flushed data
2227  *
2228  * For stripes with data and parity, namely Data-Parity stripe
2229  * (STRIPE_R5C_CACHING == 0), we simply replay all the writes.
2230  *
2231  * For stripes with only data, namely Data-Only stripe
2232  * (STRIPE_R5C_CACHING == 1), we load them to stripe cache state machine.
2233  *
2234  * For a stripe, if we see data after parity, we should discard all previous
2235  * data and parity for this stripe, as these data are already flushed to
2236  * the array.
2237  *
2238  * At the end of the scan, we return the new journal_tail, which points to
2239  * first data-only stripe on the journal device, or next invalid meta block.
2240  */
r5c_recovery_flush_log(struct r5l_log * log,struct r5l_recovery_ctx * ctx)2241 static int r5c_recovery_flush_log(struct r5l_log *log,
2242 				  struct r5l_recovery_ctx *ctx)
2243 {
2244 	struct stripe_head *sh;
2245 	int ret = 0;
2246 
2247 	/* scan through the log */
2248 	while (1) {
2249 		if (r5l_recovery_read_meta_block(log, ctx))
2250 			break;
2251 
2252 		ret = r5c_recovery_analyze_meta_block(log, ctx,
2253 						      &ctx->cached_list);
2254 		/*
2255 		 * -EAGAIN means mismatch in data block, in this case, we still
2256 		 * try scan the next metablock
2257 		 */
2258 		if (ret && ret != -EAGAIN)
2259 			break;   /* ret == -EINVAL or -ENOMEM */
2260 		ctx->seq++;
2261 		ctx->pos = r5l_ring_add(log, ctx->pos, ctx->meta_total_blocks);
2262 	}
2263 
2264 	if (ret == -ENOMEM) {
2265 		r5c_recovery_drop_stripes(&ctx->cached_list, ctx);
2266 		return ret;
2267 	}
2268 
2269 	/* replay data-parity stripes */
2270 	r5c_recovery_replay_stripes(&ctx->cached_list, ctx);
2271 
2272 	/* load data-only stripes to stripe cache */
2273 	list_for_each_entry(sh, &ctx->cached_list, lru) {
2274 		WARN_ON(!test_bit(STRIPE_R5C_CACHING, &sh->state));
2275 		r5c_recovery_load_one_stripe(log, sh);
2276 		ctx->data_only_stripes++;
2277 	}
2278 
2279 	return 0;
2280 }
2281 
2282 /*
2283  * we did a recovery. Now ctx.pos points to an invalid meta block. New
2284  * log will start here. but we can't let superblock point to last valid
2285  * meta block. The log might looks like:
2286  * | meta 1| meta 2| meta 3|
2287  * meta 1 is valid, meta 2 is invalid. meta 3 could be valid. If
2288  * superblock points to meta 1, we write a new valid meta 2n.  if crash
2289  * happens again, new recovery will start from meta 1. Since meta 2n is
2290  * valid now, recovery will think meta 3 is valid, which is wrong.
2291  * The solution is we create a new meta in meta2 with its seq == meta
2292  * 1's seq + 10000 and let superblock points to meta2. The same recovery
2293  * will not think meta 3 is a valid meta, because its seq doesn't match
2294  */
2295 
2296 /*
2297  * Before recovery, the log looks like the following
2298  *
2299  *   ---------------------------------------------
2300  *   |           valid log        | invalid log  |
2301  *   ---------------------------------------------
2302  *   ^
2303  *   |- log->last_checkpoint
2304  *   |- log->last_cp_seq
2305  *
2306  * Now we scan through the log until we see invalid entry
2307  *
2308  *   ---------------------------------------------
2309  *   |           valid log        | invalid log  |
2310  *   ---------------------------------------------
2311  *   ^                            ^
2312  *   |- log->last_checkpoint      |- ctx->pos
2313  *   |- log->last_cp_seq          |- ctx->seq
2314  *
2315  * From this point, we need to increase seq number by 10 to avoid
2316  * confusing next recovery.
2317  *
2318  *   ---------------------------------------------
2319  *   |           valid log        | invalid log  |
2320  *   ---------------------------------------------
2321  *   ^                              ^
2322  *   |- log->last_checkpoint        |- ctx->pos+1
2323  *   |- log->last_cp_seq            |- ctx->seq+10001
2324  *
2325  * However, it is not safe to start the state machine yet, because data only
2326  * parities are not yet secured in RAID. To save these data only parities, we
2327  * rewrite them from seq+11.
2328  *
2329  *   -----------------------------------------------------------------
2330  *   |           valid log        | data only stripes | invalid log  |
2331  *   -----------------------------------------------------------------
2332  *   ^                                                ^
2333  *   |- log->last_checkpoint                          |- ctx->pos+n
2334  *   |- log->last_cp_seq                              |- ctx->seq+10000+n
2335  *
2336  * If failure happens again during this process, the recovery can safe start
2337  * again from log->last_checkpoint.
2338  *
2339  * Once data only stripes are rewritten to journal, we move log_tail
2340  *
2341  *   -----------------------------------------------------------------
2342  *   |     old log        |    data only stripes    | invalid log  |
2343  *   -----------------------------------------------------------------
2344  *                        ^                         ^
2345  *                        |- log->last_checkpoint   |- ctx->pos+n
2346  *                        |- log->last_cp_seq       |- ctx->seq+10000+n
2347  *
2348  * Then we can safely start the state machine. If failure happens from this
2349  * point on, the recovery will start from new log->last_checkpoint.
2350  */
2351 static int
r5c_recovery_rewrite_data_only_stripes(struct r5l_log * log,struct r5l_recovery_ctx * ctx)2352 r5c_recovery_rewrite_data_only_stripes(struct r5l_log *log,
2353 				       struct r5l_recovery_ctx *ctx)
2354 {
2355 	struct stripe_head *sh;
2356 	struct mddev *mddev = log->rdev->mddev;
2357 	struct page *page;
2358 	sector_t next_checkpoint = MaxSector;
2359 
2360 	page = alloc_page(GFP_KERNEL);
2361 	if (!page) {
2362 		pr_err("md/raid:%s: cannot allocate memory to rewrite data only stripes\n",
2363 		       mdname(mddev));
2364 		return -ENOMEM;
2365 	}
2366 
2367 	WARN_ON(list_empty(&ctx->cached_list));
2368 
2369 	list_for_each_entry(sh, &ctx->cached_list, lru) {
2370 		struct r5l_meta_block *mb;
2371 		int i;
2372 		int offset;
2373 		sector_t write_pos;
2374 
2375 		WARN_ON(!test_bit(STRIPE_R5C_CACHING, &sh->state));
2376 		r5l_recovery_create_empty_meta_block(log, page,
2377 						     ctx->pos, ctx->seq);
2378 		mb = page_address(page);
2379 		offset = le32_to_cpu(mb->meta_size);
2380 		write_pos = r5l_ring_add(log, ctx->pos, BLOCK_SECTORS);
2381 
2382 		for (i = sh->disks; i--; ) {
2383 			struct r5dev *dev = &sh->dev[i];
2384 			struct r5l_payload_data_parity *payload;
2385 			void *addr;
2386 
2387 			if (test_bit(R5_InJournal, &dev->flags)) {
2388 				payload = (void *)mb + offset;
2389 				payload->header.type = cpu_to_le16(
2390 					R5LOG_PAYLOAD_DATA);
2391 				payload->size = cpu_to_le32(BLOCK_SECTORS);
2392 				payload->location = cpu_to_le64(
2393 					raid5_compute_blocknr(sh, i, 0));
2394 				addr = kmap_atomic(dev->page);
2395 				payload->checksum[0] = cpu_to_le32(
2396 					crc32c_le(log->uuid_checksum, addr,
2397 						  PAGE_SIZE));
2398 				kunmap_atomic(addr);
2399 				sync_page_io(log->rdev, write_pos, PAGE_SIZE,
2400 					     dev->page, REQ_OP_WRITE, 0, false);
2401 				write_pos = r5l_ring_add(log, write_pos,
2402 							 BLOCK_SECTORS);
2403 				offset += sizeof(__le32) +
2404 					sizeof(struct r5l_payload_data_parity);
2405 
2406 			}
2407 		}
2408 		mb->meta_size = cpu_to_le32(offset);
2409 		mb->checksum = cpu_to_le32(crc32c_le(log->uuid_checksum,
2410 						     mb, PAGE_SIZE));
2411 		sync_page_io(log->rdev, ctx->pos, PAGE_SIZE, page,
2412 			     REQ_OP_WRITE, REQ_SYNC | REQ_FUA, false);
2413 		sh->log_start = ctx->pos;
2414 		list_add_tail(&sh->r5c, &log->stripe_in_journal_list);
2415 		atomic_inc(&log->stripe_in_journal_count);
2416 		ctx->pos = write_pos;
2417 		ctx->seq += 1;
2418 		next_checkpoint = sh->log_start;
2419 	}
2420 	log->next_checkpoint = next_checkpoint;
2421 	__free_page(page);
2422 	return 0;
2423 }
2424 
r5c_recovery_flush_data_only_stripes(struct r5l_log * log,struct r5l_recovery_ctx * ctx)2425 static void r5c_recovery_flush_data_only_stripes(struct r5l_log *log,
2426 						 struct r5l_recovery_ctx *ctx)
2427 {
2428 	struct mddev *mddev = log->rdev->mddev;
2429 	struct r5conf *conf = mddev->private;
2430 	struct stripe_head *sh, *next;
2431 	bool cleared_pending = false;
2432 
2433 	if (ctx->data_only_stripes == 0)
2434 		return;
2435 
2436 	if (test_bit(MD_SB_CHANGE_PENDING, &mddev->sb_flags)) {
2437 		cleared_pending = true;
2438 		clear_bit(MD_SB_CHANGE_PENDING, &mddev->sb_flags);
2439 	}
2440 	log->r5c_journal_mode = R5C_JOURNAL_MODE_WRITE_BACK;
2441 
2442 	list_for_each_entry_safe(sh, next, &ctx->cached_list, lru) {
2443 		r5c_make_stripe_write_out(sh);
2444 		set_bit(STRIPE_HANDLE, &sh->state);
2445 		list_del_init(&sh->lru);
2446 		raid5_release_stripe(sh);
2447 	}
2448 
2449 	/* reuse conf->wait_for_quiescent in recovery */
2450 	wait_event(conf->wait_for_quiescent,
2451 		   atomic_read(&conf->active_stripes) == 0);
2452 
2453 	log->r5c_journal_mode = R5C_JOURNAL_MODE_WRITE_THROUGH;
2454 	if (cleared_pending)
2455 		set_bit(MD_SB_CHANGE_PENDING, &mddev->sb_flags);
2456 }
2457 
r5l_recovery_log(struct r5l_log * log)2458 static int r5l_recovery_log(struct r5l_log *log)
2459 {
2460 	struct mddev *mddev = log->rdev->mddev;
2461 	struct r5l_recovery_ctx *ctx;
2462 	int ret;
2463 	sector_t pos;
2464 
2465 	ctx = kzalloc(sizeof(*ctx), GFP_KERNEL);
2466 	if (!ctx)
2467 		return -ENOMEM;
2468 
2469 	ctx->pos = log->last_checkpoint;
2470 	ctx->seq = log->last_cp_seq;
2471 	INIT_LIST_HEAD(&ctx->cached_list);
2472 	ctx->meta_page = alloc_page(GFP_KERNEL);
2473 
2474 	if (!ctx->meta_page) {
2475 		ret =  -ENOMEM;
2476 		goto meta_page;
2477 	}
2478 
2479 	if (r5l_recovery_allocate_ra_pool(log, ctx) != 0) {
2480 		ret = -ENOMEM;
2481 		goto ra_pool;
2482 	}
2483 
2484 	ret = r5c_recovery_flush_log(log, ctx);
2485 
2486 	if (ret)
2487 		goto error;
2488 
2489 	pos = ctx->pos;
2490 	ctx->seq += 10000;
2491 
2492 	if ((ctx->data_only_stripes == 0) && (ctx->data_parity_stripes == 0))
2493 		pr_info("md/raid:%s: starting from clean shutdown\n",
2494 			 mdname(mddev));
2495 	else
2496 		pr_info("md/raid:%s: recovering %d data-only stripes and %d data-parity stripes\n",
2497 			 mdname(mddev), ctx->data_only_stripes,
2498 			 ctx->data_parity_stripes);
2499 
2500 	if (ctx->data_only_stripes == 0) {
2501 		log->next_checkpoint = ctx->pos;
2502 		r5l_log_write_empty_meta_block(log, ctx->pos, ctx->seq++);
2503 		ctx->pos = r5l_ring_add(log, ctx->pos, BLOCK_SECTORS);
2504 	} else if (r5c_recovery_rewrite_data_only_stripes(log, ctx)) {
2505 		pr_err("md/raid:%s: failed to rewrite stripes to journal\n",
2506 		       mdname(mddev));
2507 		ret =  -EIO;
2508 		goto error;
2509 	}
2510 
2511 	log->log_start = ctx->pos;
2512 	log->seq = ctx->seq;
2513 	log->last_checkpoint = pos;
2514 	r5l_write_super(log, pos);
2515 
2516 	r5c_recovery_flush_data_only_stripes(log, ctx);
2517 	ret = 0;
2518 error:
2519 	r5l_recovery_free_ra_pool(log, ctx);
2520 ra_pool:
2521 	__free_page(ctx->meta_page);
2522 meta_page:
2523 	kfree(ctx);
2524 	return ret;
2525 }
2526 
r5l_write_super(struct r5l_log * log,sector_t cp)2527 static void r5l_write_super(struct r5l_log *log, sector_t cp)
2528 {
2529 	struct mddev *mddev = log->rdev->mddev;
2530 
2531 	log->rdev->journal_tail = cp;
2532 	set_bit(MD_SB_CHANGE_DEVS, &mddev->sb_flags);
2533 }
2534 
r5c_journal_mode_show(struct mddev * mddev,char * page)2535 static ssize_t r5c_journal_mode_show(struct mddev *mddev, char *page)
2536 {
2537 	struct r5conf *conf;
2538 	int ret;
2539 
2540 	spin_lock(&mddev->lock);
2541 	conf = mddev->private;
2542 	if (!conf || !conf->log) {
2543 		spin_unlock(&mddev->lock);
2544 		return 0;
2545 	}
2546 
2547 	switch (conf->log->r5c_journal_mode) {
2548 	case R5C_JOURNAL_MODE_WRITE_THROUGH:
2549 		ret = snprintf(
2550 			page, PAGE_SIZE, "[%s] %s\n",
2551 			r5c_journal_mode_str[R5C_JOURNAL_MODE_WRITE_THROUGH],
2552 			r5c_journal_mode_str[R5C_JOURNAL_MODE_WRITE_BACK]);
2553 		break;
2554 	case R5C_JOURNAL_MODE_WRITE_BACK:
2555 		ret = snprintf(
2556 			page, PAGE_SIZE, "%s [%s]\n",
2557 			r5c_journal_mode_str[R5C_JOURNAL_MODE_WRITE_THROUGH],
2558 			r5c_journal_mode_str[R5C_JOURNAL_MODE_WRITE_BACK]);
2559 		break;
2560 	default:
2561 		ret = 0;
2562 	}
2563 	spin_unlock(&mddev->lock);
2564 	return ret;
2565 }
2566 
2567 /*
2568  * Set journal cache mode on @mddev (external API initially needed by dm-raid).
2569  *
2570  * @mode as defined in 'enum r5c_journal_mode'.
2571  *
2572  */
r5c_journal_mode_set(struct mddev * mddev,int mode)2573 int r5c_journal_mode_set(struct mddev *mddev, int mode)
2574 {
2575 	struct r5conf *conf;
2576 
2577 	if (mode < R5C_JOURNAL_MODE_WRITE_THROUGH ||
2578 	    mode > R5C_JOURNAL_MODE_WRITE_BACK)
2579 		return -EINVAL;
2580 
2581 	conf = mddev->private;
2582 	if (!conf || !conf->log)
2583 		return -ENODEV;
2584 
2585 	if (raid5_calc_degraded(conf) > 0 &&
2586 	    mode == R5C_JOURNAL_MODE_WRITE_BACK)
2587 		return -EINVAL;
2588 
2589 	mddev_suspend(mddev);
2590 	conf->log->r5c_journal_mode = mode;
2591 	mddev_resume(mddev);
2592 
2593 	pr_debug("md/raid:%s: setting r5c cache mode to %d: %s\n",
2594 		 mdname(mddev), mode, r5c_journal_mode_str[mode]);
2595 	return 0;
2596 }
2597 EXPORT_SYMBOL(r5c_journal_mode_set);
2598 
r5c_journal_mode_store(struct mddev * mddev,const char * page,size_t length)2599 static ssize_t r5c_journal_mode_store(struct mddev *mddev,
2600 				      const char *page, size_t length)
2601 {
2602 	int mode = ARRAY_SIZE(r5c_journal_mode_str);
2603 	size_t len = length;
2604 	int ret;
2605 
2606 	if (len < 2)
2607 		return -EINVAL;
2608 
2609 	if (page[len - 1] == '\n')
2610 		len--;
2611 
2612 	while (mode--)
2613 		if (strlen(r5c_journal_mode_str[mode]) == len &&
2614 		    !strncmp(page, r5c_journal_mode_str[mode], len))
2615 			break;
2616 	ret = mddev_lock(mddev);
2617 	if (ret)
2618 		return ret;
2619 	ret = r5c_journal_mode_set(mddev, mode);
2620 	mddev_unlock(mddev);
2621 	return ret ?: length;
2622 }
2623 
2624 struct md_sysfs_entry
2625 r5c_journal_mode = __ATTR(journal_mode, 0644,
2626 			  r5c_journal_mode_show, r5c_journal_mode_store);
2627 
2628 /*
2629  * Try handle write operation in caching phase. This function should only
2630  * be called in write-back mode.
2631  *
2632  * If all outstanding writes can be handled in caching phase, returns 0
2633  * If writes requires write-out phase, call r5c_make_stripe_write_out()
2634  * and returns -EAGAIN
2635  */
r5c_try_caching_write(struct r5conf * conf,struct stripe_head * sh,struct stripe_head_state * s,int disks)2636 int r5c_try_caching_write(struct r5conf *conf,
2637 			  struct stripe_head *sh,
2638 			  struct stripe_head_state *s,
2639 			  int disks)
2640 {
2641 	struct r5l_log *log = conf->log;
2642 	int i;
2643 	struct r5dev *dev;
2644 	int to_cache = 0;
2645 	void **pslot;
2646 	sector_t tree_index;
2647 	int ret;
2648 	uintptr_t refcount;
2649 
2650 	BUG_ON(!r5c_is_writeback(log));
2651 
2652 	if (!test_bit(STRIPE_R5C_CACHING, &sh->state)) {
2653 		/*
2654 		 * There are two different scenarios here:
2655 		 *  1. The stripe has some data cached, and it is sent to
2656 		 *     write-out phase for reclaim
2657 		 *  2. The stripe is clean, and this is the first write
2658 		 *
2659 		 * For 1, return -EAGAIN, so we continue with
2660 		 * handle_stripe_dirtying().
2661 		 *
2662 		 * For 2, set STRIPE_R5C_CACHING and continue with caching
2663 		 * write.
2664 		 */
2665 
2666 		/* case 1: anything injournal or anything in written */
2667 		if (s->injournal > 0 || s->written > 0)
2668 			return -EAGAIN;
2669 		/* case 2 */
2670 		set_bit(STRIPE_R5C_CACHING, &sh->state);
2671 	}
2672 
2673 	/*
2674 	 * When run in degraded mode, array is set to write-through mode.
2675 	 * This check helps drain pending write safely in the transition to
2676 	 * write-through mode.
2677 	 *
2678 	 * When a stripe is syncing, the write is also handled in write
2679 	 * through mode.
2680 	 */
2681 	if (s->failed || test_bit(STRIPE_SYNCING, &sh->state)) {
2682 		r5c_make_stripe_write_out(sh);
2683 		return -EAGAIN;
2684 	}
2685 
2686 	for (i = disks; i--; ) {
2687 		dev = &sh->dev[i];
2688 		/* if non-overwrite, use writing-out phase */
2689 		if (dev->towrite && !test_bit(R5_OVERWRITE, &dev->flags) &&
2690 		    !test_bit(R5_InJournal, &dev->flags)) {
2691 			r5c_make_stripe_write_out(sh);
2692 			return -EAGAIN;
2693 		}
2694 	}
2695 
2696 	/* if the stripe is not counted in big_stripe_tree, add it now */
2697 	if (!test_bit(STRIPE_R5C_PARTIAL_STRIPE, &sh->state) &&
2698 	    !test_bit(STRIPE_R5C_FULL_STRIPE, &sh->state)) {
2699 		tree_index = r5c_tree_index(conf, sh->sector);
2700 		spin_lock(&log->tree_lock);
2701 		pslot = radix_tree_lookup_slot(&log->big_stripe_tree,
2702 					       tree_index);
2703 		if (pslot) {
2704 			refcount = (uintptr_t)radix_tree_deref_slot_protected(
2705 				pslot, &log->tree_lock) >>
2706 				R5C_RADIX_COUNT_SHIFT;
2707 			radix_tree_replace_slot(
2708 				&log->big_stripe_tree, pslot,
2709 				(void *)((refcount + 1) << R5C_RADIX_COUNT_SHIFT));
2710 		} else {
2711 			/*
2712 			 * this radix_tree_insert can fail safely, so no
2713 			 * need to call radix_tree_preload()
2714 			 */
2715 			ret = radix_tree_insert(
2716 				&log->big_stripe_tree, tree_index,
2717 				(void *)(1 << R5C_RADIX_COUNT_SHIFT));
2718 			if (ret) {
2719 				spin_unlock(&log->tree_lock);
2720 				r5c_make_stripe_write_out(sh);
2721 				return -EAGAIN;
2722 			}
2723 		}
2724 		spin_unlock(&log->tree_lock);
2725 
2726 		/*
2727 		 * set STRIPE_R5C_PARTIAL_STRIPE, this shows the stripe is
2728 		 * counted in the radix tree
2729 		 */
2730 		set_bit(STRIPE_R5C_PARTIAL_STRIPE, &sh->state);
2731 		atomic_inc(&conf->r5c_cached_partial_stripes);
2732 	}
2733 
2734 	for (i = disks; i--; ) {
2735 		dev = &sh->dev[i];
2736 		if (dev->towrite) {
2737 			set_bit(R5_Wantwrite, &dev->flags);
2738 			set_bit(R5_Wantdrain, &dev->flags);
2739 			set_bit(R5_LOCKED, &dev->flags);
2740 			to_cache++;
2741 		}
2742 	}
2743 
2744 	if (to_cache) {
2745 		set_bit(STRIPE_OP_BIODRAIN, &s->ops_request);
2746 		/*
2747 		 * set STRIPE_LOG_TRAPPED, which triggers r5c_cache_data()
2748 		 * in ops_run_io(). STRIPE_LOG_TRAPPED will be cleared in
2749 		 * r5c_handle_data_cached()
2750 		 */
2751 		set_bit(STRIPE_LOG_TRAPPED, &sh->state);
2752 	}
2753 
2754 	return 0;
2755 }
2756 
2757 /*
2758  * free extra pages (orig_page) we allocated for prexor
2759  */
r5c_release_extra_page(struct stripe_head * sh)2760 void r5c_release_extra_page(struct stripe_head *sh)
2761 {
2762 	struct r5conf *conf = sh->raid_conf;
2763 	int i;
2764 	bool using_disk_info_extra_page;
2765 
2766 	using_disk_info_extra_page =
2767 		sh->dev[0].orig_page == conf->disks[0].extra_page;
2768 
2769 	for (i = sh->disks; i--; )
2770 		if (sh->dev[i].page != sh->dev[i].orig_page) {
2771 			struct page *p = sh->dev[i].orig_page;
2772 
2773 			sh->dev[i].orig_page = sh->dev[i].page;
2774 			clear_bit(R5_OrigPageUPTDODATE, &sh->dev[i].flags);
2775 
2776 			if (!using_disk_info_extra_page)
2777 				put_page(p);
2778 		}
2779 
2780 	if (using_disk_info_extra_page) {
2781 		clear_bit(R5C_EXTRA_PAGE_IN_USE, &conf->cache_state);
2782 		md_wakeup_thread(conf->mddev->thread);
2783 	}
2784 }
2785 
r5c_use_extra_page(struct stripe_head * sh)2786 void r5c_use_extra_page(struct stripe_head *sh)
2787 {
2788 	struct r5conf *conf = sh->raid_conf;
2789 	int i;
2790 	struct r5dev *dev;
2791 
2792 	for (i = sh->disks; i--; ) {
2793 		dev = &sh->dev[i];
2794 		if (dev->orig_page != dev->page)
2795 			put_page(dev->orig_page);
2796 		dev->orig_page = conf->disks[i].extra_page;
2797 	}
2798 }
2799 
2800 /*
2801  * clean up the stripe (clear R5_InJournal for dev[pd_idx] etc.) after the
2802  * stripe is committed to RAID disks.
2803  */
r5c_finish_stripe_write_out(struct r5conf * conf,struct stripe_head * sh,struct stripe_head_state * s)2804 void r5c_finish_stripe_write_out(struct r5conf *conf,
2805 				 struct stripe_head *sh,
2806 				 struct stripe_head_state *s)
2807 {
2808 	struct r5l_log *log = conf->log;
2809 	int i;
2810 	int do_wakeup = 0;
2811 	sector_t tree_index;
2812 	void **pslot;
2813 	uintptr_t refcount;
2814 
2815 	if (!log || !test_bit(R5_InJournal, &sh->dev[sh->pd_idx].flags))
2816 		return;
2817 
2818 	WARN_ON(test_bit(STRIPE_R5C_CACHING, &sh->state));
2819 	clear_bit(R5_InJournal, &sh->dev[sh->pd_idx].flags);
2820 
2821 	if (log->r5c_journal_mode == R5C_JOURNAL_MODE_WRITE_THROUGH)
2822 		return;
2823 
2824 	for (i = sh->disks; i--; ) {
2825 		clear_bit(R5_InJournal, &sh->dev[i].flags);
2826 		if (test_and_clear_bit(R5_Overlap, &sh->dev[i].flags))
2827 			do_wakeup = 1;
2828 	}
2829 
2830 	/*
2831 	 * analyse_stripe() runs before r5c_finish_stripe_write_out(),
2832 	 * We updated R5_InJournal, so we also update s->injournal.
2833 	 */
2834 	s->injournal = 0;
2835 
2836 	if (test_and_clear_bit(STRIPE_FULL_WRITE, &sh->state))
2837 		if (atomic_dec_and_test(&conf->pending_full_writes))
2838 			md_wakeup_thread(conf->mddev->thread);
2839 
2840 	if (do_wakeup)
2841 		wake_up(&conf->wait_for_overlap);
2842 
2843 	spin_lock_irq(&log->stripe_in_journal_lock);
2844 	list_del_init(&sh->r5c);
2845 	spin_unlock_irq(&log->stripe_in_journal_lock);
2846 	sh->log_start = MaxSector;
2847 
2848 	atomic_dec(&log->stripe_in_journal_count);
2849 	r5c_update_log_state(log);
2850 
2851 	/* stop counting this stripe in big_stripe_tree */
2852 	if (test_bit(STRIPE_R5C_PARTIAL_STRIPE, &sh->state) ||
2853 	    test_bit(STRIPE_R5C_FULL_STRIPE, &sh->state)) {
2854 		tree_index = r5c_tree_index(conf, sh->sector);
2855 		spin_lock(&log->tree_lock);
2856 		pslot = radix_tree_lookup_slot(&log->big_stripe_tree,
2857 					       tree_index);
2858 		BUG_ON(pslot == NULL);
2859 		refcount = (uintptr_t)radix_tree_deref_slot_protected(
2860 			pslot, &log->tree_lock) >>
2861 			R5C_RADIX_COUNT_SHIFT;
2862 		if (refcount == 1)
2863 			radix_tree_delete(&log->big_stripe_tree, tree_index);
2864 		else
2865 			radix_tree_replace_slot(
2866 				&log->big_stripe_tree, pslot,
2867 				(void *)((refcount - 1) << R5C_RADIX_COUNT_SHIFT));
2868 		spin_unlock(&log->tree_lock);
2869 	}
2870 
2871 	if (test_and_clear_bit(STRIPE_R5C_PARTIAL_STRIPE, &sh->state)) {
2872 		BUG_ON(atomic_read(&conf->r5c_cached_partial_stripes) == 0);
2873 		atomic_dec(&conf->r5c_flushing_partial_stripes);
2874 		atomic_dec(&conf->r5c_cached_partial_stripes);
2875 	}
2876 
2877 	if (test_and_clear_bit(STRIPE_R5C_FULL_STRIPE, &sh->state)) {
2878 		BUG_ON(atomic_read(&conf->r5c_cached_full_stripes) == 0);
2879 		atomic_dec(&conf->r5c_flushing_full_stripes);
2880 		atomic_dec(&conf->r5c_cached_full_stripes);
2881 	}
2882 
2883 	r5l_append_flush_payload(log, sh->sector);
2884 	/* stripe is flused to raid disks, we can do resync now */
2885 	if (test_bit(STRIPE_SYNC_REQUESTED, &sh->state))
2886 		set_bit(STRIPE_HANDLE, &sh->state);
2887 }
2888 
r5c_cache_data(struct r5l_log * log,struct stripe_head * sh)2889 int r5c_cache_data(struct r5l_log *log, struct stripe_head *sh)
2890 {
2891 	struct r5conf *conf = sh->raid_conf;
2892 	int pages = 0;
2893 	int reserve;
2894 	int i;
2895 	int ret = 0;
2896 
2897 	BUG_ON(!log);
2898 
2899 	for (i = 0; i < sh->disks; i++) {
2900 		void *addr;
2901 
2902 		if (!test_bit(R5_Wantwrite, &sh->dev[i].flags))
2903 			continue;
2904 		addr = kmap_atomic(sh->dev[i].page);
2905 		sh->dev[i].log_checksum = crc32c_le(log->uuid_checksum,
2906 						    addr, PAGE_SIZE);
2907 		kunmap_atomic(addr);
2908 		pages++;
2909 	}
2910 	WARN_ON(pages == 0);
2911 
2912 	/*
2913 	 * The stripe must enter state machine again to call endio, so
2914 	 * don't delay.
2915 	 */
2916 	clear_bit(STRIPE_DELAYED, &sh->state);
2917 	atomic_inc(&sh->count);
2918 
2919 	mutex_lock(&log->io_mutex);
2920 	/* meta + data */
2921 	reserve = (1 + pages) << (PAGE_SHIFT - 9);
2922 
2923 	if (test_bit(R5C_LOG_CRITICAL, &conf->cache_state) &&
2924 	    sh->log_start == MaxSector)
2925 		r5l_add_no_space_stripe(log, sh);
2926 	else if (!r5l_has_free_space(log, reserve)) {
2927 		if (sh->log_start == log->last_checkpoint)
2928 			BUG();
2929 		else
2930 			r5l_add_no_space_stripe(log, sh);
2931 	} else {
2932 		ret = r5l_log_stripe(log, sh, pages, 0);
2933 		if (ret) {
2934 			spin_lock_irq(&log->io_list_lock);
2935 			list_add_tail(&sh->log_list, &log->no_mem_stripes);
2936 			spin_unlock_irq(&log->io_list_lock);
2937 		}
2938 	}
2939 
2940 	mutex_unlock(&log->io_mutex);
2941 	return 0;
2942 }
2943 
2944 /* check whether this big stripe is in write back cache. */
r5c_big_stripe_cached(struct r5conf * conf,sector_t sect)2945 bool r5c_big_stripe_cached(struct r5conf *conf, sector_t sect)
2946 {
2947 	struct r5l_log *log = conf->log;
2948 	sector_t tree_index;
2949 	void *slot;
2950 
2951 	if (!log)
2952 		return false;
2953 
2954 	WARN_ON_ONCE(!rcu_read_lock_held());
2955 	tree_index = r5c_tree_index(conf, sect);
2956 	slot = radix_tree_lookup(&log->big_stripe_tree, tree_index);
2957 	return slot != NULL;
2958 }
2959 
r5l_load_log(struct r5l_log * log)2960 static int r5l_load_log(struct r5l_log *log)
2961 {
2962 	struct md_rdev *rdev = log->rdev;
2963 	struct page *page;
2964 	struct r5l_meta_block *mb;
2965 	sector_t cp = log->rdev->journal_tail;
2966 	u32 stored_crc, expected_crc;
2967 	bool create_super = false;
2968 	int ret = 0;
2969 
2970 	/* Make sure it's valid */
2971 	if (cp >= rdev->sectors || round_down(cp, BLOCK_SECTORS) != cp)
2972 		cp = 0;
2973 	page = alloc_page(GFP_KERNEL);
2974 	if (!page)
2975 		return -ENOMEM;
2976 
2977 	if (!sync_page_io(rdev, cp, PAGE_SIZE, page, REQ_OP_READ, 0, false)) {
2978 		ret = -EIO;
2979 		goto ioerr;
2980 	}
2981 	mb = page_address(page);
2982 
2983 	if (le32_to_cpu(mb->magic) != R5LOG_MAGIC ||
2984 	    mb->version != R5LOG_VERSION) {
2985 		create_super = true;
2986 		goto create;
2987 	}
2988 	stored_crc = le32_to_cpu(mb->checksum);
2989 	mb->checksum = 0;
2990 	expected_crc = crc32c_le(log->uuid_checksum, mb, PAGE_SIZE);
2991 	if (stored_crc != expected_crc) {
2992 		create_super = true;
2993 		goto create;
2994 	}
2995 	if (le64_to_cpu(mb->position) != cp) {
2996 		create_super = true;
2997 		goto create;
2998 	}
2999 create:
3000 	if (create_super) {
3001 		log->last_cp_seq = prandom_u32();
3002 		cp = 0;
3003 		r5l_log_write_empty_meta_block(log, cp, log->last_cp_seq);
3004 		/*
3005 		 * Make sure super points to correct address. Log might have
3006 		 * data very soon. If super hasn't correct log tail address,
3007 		 * recovery can't find the log
3008 		 */
3009 		r5l_write_super(log, cp);
3010 	} else
3011 		log->last_cp_seq = le64_to_cpu(mb->seq);
3012 
3013 	log->device_size = round_down(rdev->sectors, BLOCK_SECTORS);
3014 	log->max_free_space = log->device_size >> RECLAIM_MAX_FREE_SPACE_SHIFT;
3015 	if (log->max_free_space > RECLAIM_MAX_FREE_SPACE)
3016 		log->max_free_space = RECLAIM_MAX_FREE_SPACE;
3017 	log->last_checkpoint = cp;
3018 
3019 	__free_page(page);
3020 
3021 	if (create_super) {
3022 		log->log_start = r5l_ring_add(log, cp, BLOCK_SECTORS);
3023 		log->seq = log->last_cp_seq + 1;
3024 		log->next_checkpoint = cp;
3025 	} else
3026 		ret = r5l_recovery_log(log);
3027 
3028 	r5c_update_log_state(log);
3029 	return ret;
3030 ioerr:
3031 	__free_page(page);
3032 	return ret;
3033 }
3034 
r5l_start(struct r5l_log * log)3035 int r5l_start(struct r5l_log *log)
3036 {
3037 	int ret;
3038 
3039 	if (!log)
3040 		return 0;
3041 
3042 	ret = r5l_load_log(log);
3043 	if (ret) {
3044 		struct mddev *mddev = log->rdev->mddev;
3045 		struct r5conf *conf = mddev->private;
3046 
3047 		r5l_exit_log(conf);
3048 	}
3049 	return ret;
3050 }
3051 
r5c_update_on_rdev_error(struct mddev * mddev,struct md_rdev * rdev)3052 void r5c_update_on_rdev_error(struct mddev *mddev, struct md_rdev *rdev)
3053 {
3054 	struct r5conf *conf = mddev->private;
3055 	struct r5l_log *log = conf->log;
3056 
3057 	if (!log)
3058 		return;
3059 
3060 	if ((raid5_calc_degraded(conf) > 0 ||
3061 	     test_bit(Journal, &rdev->flags)) &&
3062 	    conf->log->r5c_journal_mode == R5C_JOURNAL_MODE_WRITE_BACK)
3063 		schedule_work(&log->disable_writeback_work);
3064 }
3065 
r5l_init_log(struct r5conf * conf,struct md_rdev * rdev)3066 int r5l_init_log(struct r5conf *conf, struct md_rdev *rdev)
3067 {
3068 	struct request_queue *q = bdev_get_queue(rdev->bdev);
3069 	struct r5l_log *log;
3070 	char b[BDEVNAME_SIZE];
3071 	int ret;
3072 
3073 	pr_debug("md/raid:%s: using device %s as journal\n",
3074 		 mdname(conf->mddev), bdevname(rdev->bdev, b));
3075 
3076 	if (PAGE_SIZE != 4096)
3077 		return -EINVAL;
3078 
3079 	/*
3080 	 * The PAGE_SIZE must be big enough to hold 1 r5l_meta_block and
3081 	 * raid_disks r5l_payload_data_parity.
3082 	 *
3083 	 * Write journal and cache does not work for very big array
3084 	 * (raid_disks > 203)
3085 	 */
3086 	if (sizeof(struct r5l_meta_block) +
3087 	    ((sizeof(struct r5l_payload_data_parity) + sizeof(__le32)) *
3088 	     conf->raid_disks) > PAGE_SIZE) {
3089 		pr_err("md/raid:%s: write journal/cache doesn't work for array with %d disks\n",
3090 		       mdname(conf->mddev), conf->raid_disks);
3091 		return -EINVAL;
3092 	}
3093 
3094 	log = kzalloc(sizeof(*log), GFP_KERNEL);
3095 	if (!log)
3096 		return -ENOMEM;
3097 	log->rdev = rdev;
3098 
3099 	log->need_cache_flush = test_bit(QUEUE_FLAG_WC, &q->queue_flags) != 0;
3100 
3101 	log->uuid_checksum = crc32c_le(~0, rdev->mddev->uuid,
3102 				       sizeof(rdev->mddev->uuid));
3103 
3104 	mutex_init(&log->io_mutex);
3105 
3106 	spin_lock_init(&log->io_list_lock);
3107 	INIT_LIST_HEAD(&log->running_ios);
3108 	INIT_LIST_HEAD(&log->io_end_ios);
3109 	INIT_LIST_HEAD(&log->flushing_ios);
3110 	INIT_LIST_HEAD(&log->finished_ios);
3111 	bio_init(&log->flush_bio, NULL, 0);
3112 
3113 	log->io_kc = KMEM_CACHE(r5l_io_unit, 0);
3114 	if (!log->io_kc)
3115 		goto io_kc;
3116 
3117 	ret = mempool_init_slab_pool(&log->io_pool, R5L_POOL_SIZE, log->io_kc);
3118 	if (ret)
3119 		goto io_pool;
3120 
3121 	ret = bioset_init(&log->bs, R5L_POOL_SIZE, 0, BIOSET_NEED_BVECS);
3122 	if (ret)
3123 		goto io_bs;
3124 
3125 	ret = mempool_init_page_pool(&log->meta_pool, R5L_POOL_SIZE, 0);
3126 	if (ret)
3127 		goto out_mempool;
3128 
3129 	spin_lock_init(&log->tree_lock);
3130 	INIT_RADIX_TREE(&log->big_stripe_tree, GFP_NOWAIT | __GFP_NOWARN);
3131 
3132 	log->reclaim_thread = md_register_thread(r5l_reclaim_thread,
3133 						 log->rdev->mddev, "reclaim");
3134 	if (!log->reclaim_thread)
3135 		goto reclaim_thread;
3136 	log->reclaim_thread->timeout = R5C_RECLAIM_WAKEUP_INTERVAL;
3137 
3138 	init_waitqueue_head(&log->iounit_wait);
3139 
3140 	INIT_LIST_HEAD(&log->no_mem_stripes);
3141 
3142 	INIT_LIST_HEAD(&log->no_space_stripes);
3143 	spin_lock_init(&log->no_space_stripes_lock);
3144 
3145 	INIT_WORK(&log->deferred_io_work, r5l_submit_io_async);
3146 	INIT_WORK(&log->disable_writeback_work, r5c_disable_writeback_async);
3147 
3148 	log->r5c_journal_mode = R5C_JOURNAL_MODE_WRITE_THROUGH;
3149 	INIT_LIST_HEAD(&log->stripe_in_journal_list);
3150 	spin_lock_init(&log->stripe_in_journal_lock);
3151 	atomic_set(&log->stripe_in_journal_count, 0);
3152 
3153 	rcu_assign_pointer(conf->log, log);
3154 
3155 	set_bit(MD_HAS_JOURNAL, &conf->mddev->flags);
3156 	return 0;
3157 
3158 reclaim_thread:
3159 	mempool_exit(&log->meta_pool);
3160 out_mempool:
3161 	bioset_exit(&log->bs);
3162 io_bs:
3163 	mempool_exit(&log->io_pool);
3164 io_pool:
3165 	kmem_cache_destroy(log->io_kc);
3166 io_kc:
3167 	kfree(log);
3168 	return -EINVAL;
3169 }
3170 
r5l_exit_log(struct r5conf * conf)3171 void r5l_exit_log(struct r5conf *conf)
3172 {
3173 	struct r5l_log *log = conf->log;
3174 
3175 	conf->log = NULL;
3176 	synchronize_rcu();
3177 
3178 	/* Ensure disable_writeback_work wakes up and exits */
3179 	wake_up(&conf->mddev->sb_wait);
3180 	flush_work(&log->disable_writeback_work);
3181 	md_unregister_thread(&log->reclaim_thread);
3182 	mempool_exit(&log->meta_pool);
3183 	bioset_exit(&log->bs);
3184 	mempool_exit(&log->io_pool);
3185 	kmem_cache_destroy(log->io_kc);
3186 	kfree(log);
3187 }
3188