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