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7#include <linux/device-mapper.h>
8
9#include <linux/module.h>
10#include <linux/init.h>
11#include <linux/blkdev.h>
12#include <linux/bio.h>
13#include <linux/dax.h>
14#include <linux/slab.h>
15#include <linux/kthread.h>
16#include <linux/freezer.h>
17#include <linux/uio.h>
18
19#define DM_MSG_PREFIX "log-writes"
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54
55#define LOG_FLUSH_FLAG (1 << 0)
56#define LOG_FUA_FLAG (1 << 1)
57#define LOG_DISCARD_FLAG (1 << 2)
58#define LOG_MARK_FLAG (1 << 3)
59
60#define WRITE_LOG_VERSION 1ULL
61#define WRITE_LOG_MAGIC 0x6a736677736872ULL
62
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78
79struct log_write_super {
80 __le64 magic;
81 __le64 version;
82 __le64 nr_entries;
83 __le32 sectorsize;
84};
85
86
87
88
89
90
91
92
93struct log_write_entry {
94 __le64 sector;
95 __le64 nr_sectors;
96 __le64 flags;
97 __le64 data_len;
98};
99
100struct log_writes_c {
101 struct dm_dev *dev;
102 struct dm_dev *logdev;
103 u64 logged_entries;
104 u32 sectorsize;
105 u32 sectorshift;
106 atomic_t io_blocks;
107 atomic_t pending_blocks;
108 sector_t next_sector;
109 sector_t end_sector;
110 bool logging_enabled;
111 bool device_supports_discard;
112 spinlock_t blocks_lock;
113 struct list_head unflushed_blocks;
114 struct list_head logging_blocks;
115 wait_queue_head_t wait;
116 struct task_struct *log_kthread;
117};
118
119struct pending_block {
120 int vec_cnt;
121 u64 flags;
122 sector_t sector;
123 sector_t nr_sectors;
124 char *data;
125 u32 datalen;
126 struct list_head list;
127 struct bio_vec vecs[0];
128};
129
130struct per_bio_data {
131 struct pending_block *block;
132};
133
134static inline sector_t bio_to_dev_sectors(struct log_writes_c *lc,
135 sector_t sectors)
136{
137 return sectors >> (lc->sectorshift - SECTOR_SHIFT);
138}
139
140static inline sector_t dev_to_bio_sectors(struct log_writes_c *lc,
141 sector_t sectors)
142{
143 return sectors << (lc->sectorshift - SECTOR_SHIFT);
144}
145
146static void put_pending_block(struct log_writes_c *lc)
147{
148 if (atomic_dec_and_test(&lc->pending_blocks)) {
149 smp_mb__after_atomic();
150 if (waitqueue_active(&lc->wait))
151 wake_up(&lc->wait);
152 }
153}
154
155static void put_io_block(struct log_writes_c *lc)
156{
157 if (atomic_dec_and_test(&lc->io_blocks)) {
158 smp_mb__after_atomic();
159 if (waitqueue_active(&lc->wait))
160 wake_up(&lc->wait);
161 }
162}
163
164static void log_end_io(struct bio *bio)
165{
166 struct log_writes_c *lc = bio->bi_private;
167
168 if (bio->bi_status) {
169 unsigned long flags;
170
171 DMERR("Error writing log block, error=%d", bio->bi_status);
172 spin_lock_irqsave(&lc->blocks_lock, flags);
173 lc->logging_enabled = false;
174 spin_unlock_irqrestore(&lc->blocks_lock, flags);
175 }
176
177 bio_free_pages(bio);
178 put_io_block(lc);
179 bio_put(bio);
180}
181
182
183
184
185
186static void free_pending_block(struct log_writes_c *lc,
187 struct pending_block *block)
188{
189 int i;
190
191 for (i = 0; i < block->vec_cnt; i++) {
192 if (block->vecs[i].bv_page)
193 __free_page(block->vecs[i].bv_page);
194 }
195 kfree(block->data);
196 kfree(block);
197 put_pending_block(lc);
198}
199
200static int write_metadata(struct log_writes_c *lc, void *entry,
201 size_t entrylen, void *data, size_t datalen,
202 sector_t sector)
203{
204 struct bio *bio;
205 struct page *page;
206 void *ptr;
207 size_t ret;
208
209 bio = bio_alloc(GFP_KERNEL, 1);
210 if (!bio) {
211 DMERR("Couldn't alloc log bio");
212 goto error;
213 }
214 bio->bi_iter.bi_size = 0;
215 bio->bi_iter.bi_sector = sector;
216 bio_set_dev(bio, lc->logdev->bdev);
217 bio->bi_end_io = log_end_io;
218 bio->bi_private = lc;
219 bio_set_op_attrs(bio, REQ_OP_WRITE, 0);
220
221 page = alloc_page(GFP_KERNEL);
222 if (!page) {
223 DMERR("Couldn't alloc log page");
224 bio_put(bio);
225 goto error;
226 }
227
228 ptr = kmap_atomic(page);
229 memcpy(ptr, entry, entrylen);
230 if (datalen)
231 memcpy(ptr + entrylen, data, datalen);
232 memset(ptr + entrylen + datalen, 0,
233 lc->sectorsize - entrylen - datalen);
234 kunmap_atomic(ptr);
235
236 ret = bio_add_page(bio, page, lc->sectorsize, 0);
237 if (ret != lc->sectorsize) {
238 DMERR("Couldn't add page to the log block");
239 goto error_bio;
240 }
241 submit_bio(bio);
242 return 0;
243error_bio:
244 bio_put(bio);
245 __free_page(page);
246error:
247 put_io_block(lc);
248 return -1;
249}
250
251static int write_inline_data(struct log_writes_c *lc, void *entry,
252 size_t entrylen, void *data, size_t datalen,
253 sector_t sector)
254{
255 int num_pages, bio_pages, pg_datalen, pg_sectorlen, i;
256 struct page *page;
257 struct bio *bio;
258 size_t ret;
259 void *ptr;
260
261 while (datalen) {
262 num_pages = ALIGN(datalen, PAGE_SIZE) >> PAGE_SHIFT;
263 bio_pages = min(num_pages, BIO_MAX_PAGES);
264
265 atomic_inc(&lc->io_blocks);
266
267 bio = bio_alloc(GFP_KERNEL, bio_pages);
268 if (!bio) {
269 DMERR("Couldn't alloc inline data bio");
270 goto error;
271 }
272
273 bio->bi_iter.bi_size = 0;
274 bio->bi_iter.bi_sector = sector;
275 bio_set_dev(bio, lc->logdev->bdev);
276 bio->bi_end_io = log_end_io;
277 bio->bi_private = lc;
278 bio_set_op_attrs(bio, REQ_OP_WRITE, 0);
279
280 for (i = 0; i < bio_pages; i++) {
281 pg_datalen = min_t(int, datalen, PAGE_SIZE);
282 pg_sectorlen = ALIGN(pg_datalen, lc->sectorsize);
283
284 page = alloc_page(GFP_KERNEL);
285 if (!page) {
286 DMERR("Couldn't alloc inline data page");
287 goto error_bio;
288 }
289
290 ptr = kmap_atomic(page);
291 memcpy(ptr, data, pg_datalen);
292 if (pg_sectorlen > pg_datalen)
293 memset(ptr + pg_datalen, 0, pg_sectorlen - pg_datalen);
294 kunmap_atomic(ptr);
295
296 ret = bio_add_page(bio, page, pg_sectorlen, 0);
297 if (ret != pg_sectorlen) {
298 DMERR("Couldn't add page of inline data");
299 __free_page(page);
300 goto error_bio;
301 }
302
303 datalen -= pg_datalen;
304 data += pg_datalen;
305 }
306 submit_bio(bio);
307
308 sector += bio_pages * PAGE_SECTORS;
309 }
310 return 0;
311error_bio:
312 bio_free_pages(bio);
313 bio_put(bio);
314error:
315 put_io_block(lc);
316 return -1;
317}
318
319static int log_one_block(struct log_writes_c *lc,
320 struct pending_block *block, sector_t sector)
321{
322 struct bio *bio;
323 struct log_write_entry entry;
324 size_t metadatalen, ret;
325 int i;
326
327 entry.sector = cpu_to_le64(block->sector);
328 entry.nr_sectors = cpu_to_le64(block->nr_sectors);
329 entry.flags = cpu_to_le64(block->flags);
330 entry.data_len = cpu_to_le64(block->datalen);
331
332 metadatalen = (block->flags & LOG_MARK_FLAG) ? block->datalen : 0;
333 if (write_metadata(lc, &entry, sizeof(entry), block->data,
334 metadatalen, sector)) {
335 free_pending_block(lc, block);
336 return -1;
337 }
338
339 sector += dev_to_bio_sectors(lc, 1);
340
341 if (block->datalen && metadatalen == 0) {
342 if (write_inline_data(lc, &entry, sizeof(entry), block->data,
343 block->datalen, sector)) {
344 free_pending_block(lc, block);
345 return -1;
346 }
347
348 goto out;
349 }
350
351 if (!block->vec_cnt)
352 goto out;
353
354 atomic_inc(&lc->io_blocks);
355 bio = bio_alloc(GFP_KERNEL, min(block->vec_cnt, BIO_MAX_PAGES));
356 if (!bio) {
357 DMERR("Couldn't alloc log bio");
358 goto error;
359 }
360 bio->bi_iter.bi_size = 0;
361 bio->bi_iter.bi_sector = sector;
362 bio_set_dev(bio, lc->logdev->bdev);
363 bio->bi_end_io = log_end_io;
364 bio->bi_private = lc;
365 bio_set_op_attrs(bio, REQ_OP_WRITE, 0);
366
367 for (i = 0; i < block->vec_cnt; i++) {
368
369
370
371
372 ret = bio_add_page(bio, block->vecs[i].bv_page,
373 block->vecs[i].bv_len, 0);
374 if (ret != block->vecs[i].bv_len) {
375 atomic_inc(&lc->io_blocks);
376 submit_bio(bio);
377 bio = bio_alloc(GFP_KERNEL, min(block->vec_cnt - i, BIO_MAX_PAGES));
378 if (!bio) {
379 DMERR("Couldn't alloc log bio");
380 goto error;
381 }
382 bio->bi_iter.bi_size = 0;
383 bio->bi_iter.bi_sector = sector;
384 bio_set_dev(bio, lc->logdev->bdev);
385 bio->bi_end_io = log_end_io;
386 bio->bi_private = lc;
387 bio_set_op_attrs(bio, REQ_OP_WRITE, 0);
388
389 ret = bio_add_page(bio, block->vecs[i].bv_page,
390 block->vecs[i].bv_len, 0);
391 if (ret != block->vecs[i].bv_len) {
392 DMERR("Couldn't add page on new bio?");
393 bio_put(bio);
394 goto error;
395 }
396 }
397 sector += block->vecs[i].bv_len >> SECTOR_SHIFT;
398 }
399 submit_bio(bio);
400out:
401 kfree(block->data);
402 kfree(block);
403 put_pending_block(lc);
404 return 0;
405error:
406 free_pending_block(lc, block);
407 put_io_block(lc);
408 return -1;
409}
410
411static int log_super(struct log_writes_c *lc)
412{
413 struct log_write_super super;
414
415 super.magic = cpu_to_le64(WRITE_LOG_MAGIC);
416 super.version = cpu_to_le64(WRITE_LOG_VERSION);
417 super.nr_entries = cpu_to_le64(lc->logged_entries);
418 super.sectorsize = cpu_to_le32(lc->sectorsize);
419
420 if (write_metadata(lc, &super, sizeof(super), NULL, 0, 0)) {
421 DMERR("Couldn't write super");
422 return -1;
423 }
424
425 return 0;
426}
427
428static inline sector_t logdev_last_sector(struct log_writes_c *lc)
429{
430 return i_size_read(lc->logdev->bdev->bd_inode) >> SECTOR_SHIFT;
431}
432
433static int log_writes_kthread(void *arg)
434{
435 struct log_writes_c *lc = (struct log_writes_c *)arg;
436 sector_t sector = 0;
437
438 while (!kthread_should_stop()) {
439 bool super = false;
440 bool logging_enabled;
441 struct pending_block *block = NULL;
442 int ret;
443
444 spin_lock_irq(&lc->blocks_lock);
445 if (!list_empty(&lc->logging_blocks)) {
446 block = list_first_entry(&lc->logging_blocks,
447 struct pending_block, list);
448 list_del_init(&block->list);
449 if (!lc->logging_enabled)
450 goto next;
451
452 sector = lc->next_sector;
453 if (!(block->flags & LOG_DISCARD_FLAG))
454 lc->next_sector += dev_to_bio_sectors(lc, block->nr_sectors);
455 lc->next_sector += dev_to_bio_sectors(lc, 1);
456
457
458
459
460
461 if (!lc->end_sector)
462 lc->end_sector = logdev_last_sector(lc);
463 if (lc->end_sector &&
464 lc->next_sector >= lc->end_sector) {
465 DMERR("Ran out of space on the logdev");
466 lc->logging_enabled = false;
467 goto next;
468 }
469 lc->logged_entries++;
470 atomic_inc(&lc->io_blocks);
471
472 super = (block->flags & (LOG_FUA_FLAG | LOG_MARK_FLAG));
473 if (super)
474 atomic_inc(&lc->io_blocks);
475 }
476next:
477 logging_enabled = lc->logging_enabled;
478 spin_unlock_irq(&lc->blocks_lock);
479 if (block) {
480 if (logging_enabled) {
481 ret = log_one_block(lc, block, sector);
482 if (!ret && super)
483 ret = log_super(lc);
484 if (ret) {
485 spin_lock_irq(&lc->blocks_lock);
486 lc->logging_enabled = false;
487 spin_unlock_irq(&lc->blocks_lock);
488 }
489 } else
490 free_pending_block(lc, block);
491 continue;
492 }
493
494 if (!try_to_freeze()) {
495 set_current_state(TASK_INTERRUPTIBLE);
496 if (!kthread_should_stop() &&
497 list_empty(&lc->logging_blocks))
498 schedule();
499 __set_current_state(TASK_RUNNING);
500 }
501 }
502 return 0;
503}
504
505
506
507
508
509static int log_writes_ctr(struct dm_target *ti, unsigned int argc, char **argv)
510{
511 struct log_writes_c *lc;
512 struct dm_arg_set as;
513 const char *devname, *logdevname;
514 int ret;
515
516 as.argc = argc;
517 as.argv = argv;
518
519 if (argc < 2) {
520 ti->error = "Invalid argument count";
521 return -EINVAL;
522 }
523
524 lc = kzalloc(sizeof(struct log_writes_c), GFP_KERNEL);
525 if (!lc) {
526 ti->error = "Cannot allocate context";
527 return -ENOMEM;
528 }
529 spin_lock_init(&lc->blocks_lock);
530 INIT_LIST_HEAD(&lc->unflushed_blocks);
531 INIT_LIST_HEAD(&lc->logging_blocks);
532 init_waitqueue_head(&lc->wait);
533 atomic_set(&lc->io_blocks, 0);
534 atomic_set(&lc->pending_blocks, 0);
535
536 devname = dm_shift_arg(&as);
537 ret = dm_get_device(ti, devname, dm_table_get_mode(ti->table), &lc->dev);
538 if (ret) {
539 ti->error = "Device lookup failed";
540 goto bad;
541 }
542
543 logdevname = dm_shift_arg(&as);
544 ret = dm_get_device(ti, logdevname, dm_table_get_mode(ti->table),
545 &lc->logdev);
546 if (ret) {
547 ti->error = "Log device lookup failed";
548 dm_put_device(ti, lc->dev);
549 goto bad;
550 }
551
552 lc->sectorsize = bdev_logical_block_size(lc->dev->bdev);
553 lc->sectorshift = ilog2(lc->sectorsize);
554 lc->log_kthread = kthread_run(log_writes_kthread, lc, "log-write");
555 if (IS_ERR(lc->log_kthread)) {
556 ret = PTR_ERR(lc->log_kthread);
557 ti->error = "Couldn't alloc kthread";
558 dm_put_device(ti, lc->dev);
559 dm_put_device(ti, lc->logdev);
560 goto bad;
561 }
562
563
564
565
566
567
568 lc->next_sector = lc->sectorsize >> SECTOR_SHIFT;
569 lc->logging_enabled = true;
570 lc->end_sector = logdev_last_sector(lc);
571 lc->device_supports_discard = true;
572
573 ti->num_flush_bios = 1;
574 ti->flush_supported = true;
575 ti->num_discard_bios = 1;
576 ti->discards_supported = true;
577 ti->per_io_data_size = sizeof(struct per_bio_data);
578 ti->private = lc;
579 return 0;
580
581bad:
582 kfree(lc);
583 return ret;
584}
585
586static int log_mark(struct log_writes_c *lc, char *data)
587{
588 struct pending_block *block;
589 size_t maxsize = lc->sectorsize - sizeof(struct log_write_entry);
590
591 block = kzalloc(sizeof(struct pending_block), GFP_KERNEL);
592 if (!block) {
593 DMERR("Error allocating pending block");
594 return -ENOMEM;
595 }
596
597 block->data = kstrndup(data, maxsize, GFP_KERNEL);
598 if (!block->data) {
599 DMERR("Error copying mark data");
600 kfree(block);
601 return -ENOMEM;
602 }
603 atomic_inc(&lc->pending_blocks);
604 block->datalen = strlen(block->data);
605 block->flags |= LOG_MARK_FLAG;
606 spin_lock_irq(&lc->blocks_lock);
607 list_add_tail(&block->list, &lc->logging_blocks);
608 spin_unlock_irq(&lc->blocks_lock);
609 wake_up_process(lc->log_kthread);
610 return 0;
611}
612
613static int log_dax(struct log_writes_c *lc, sector_t sector, size_t bytes,
614 struct iov_iter *i)
615{
616 struct pending_block *block;
617
618 if (!bytes)
619 return 0;
620
621 block = kzalloc(sizeof(struct pending_block), GFP_KERNEL);
622 if (!block) {
623 DMERR("Error allocating dax pending block");
624 return -ENOMEM;
625 }
626
627 block->data = kzalloc(bytes, GFP_KERNEL);
628 if (!block->data) {
629 DMERR("Error allocating dax data space");
630 kfree(block);
631 return -ENOMEM;
632 }
633
634
635 if (!copy_from_iter(block->data, bytes, i)) {
636 DMERR("Error copying dax data");
637 kfree(block->data);
638 kfree(block);
639 return -EIO;
640 }
641
642
643 iov_iter_revert(i, bytes);
644
645 block->datalen = bytes;
646 block->sector = bio_to_dev_sectors(lc, sector);
647 block->nr_sectors = ALIGN(bytes, lc->sectorsize) >> lc->sectorshift;
648
649 atomic_inc(&lc->pending_blocks);
650 spin_lock_irq(&lc->blocks_lock);
651 list_add_tail(&block->list, &lc->unflushed_blocks);
652 spin_unlock_irq(&lc->blocks_lock);
653 wake_up_process(lc->log_kthread);
654
655 return 0;
656}
657
658static void log_writes_dtr(struct dm_target *ti)
659{
660 struct log_writes_c *lc = ti->private;
661
662 spin_lock_irq(&lc->blocks_lock);
663 list_splice_init(&lc->unflushed_blocks, &lc->logging_blocks);
664 spin_unlock_irq(&lc->blocks_lock);
665
666
667
668
669
670 log_mark(lc, "dm-log-writes-end");
671 wake_up_process(lc->log_kthread);
672 wait_event(lc->wait, !atomic_read(&lc->io_blocks) &&
673 !atomic_read(&lc->pending_blocks));
674 kthread_stop(lc->log_kthread);
675
676 WARN_ON(!list_empty(&lc->logging_blocks));
677 WARN_ON(!list_empty(&lc->unflushed_blocks));
678 dm_put_device(ti, lc->dev);
679 dm_put_device(ti, lc->logdev);
680 kfree(lc);
681}
682
683static void normal_map_bio(struct dm_target *ti, struct bio *bio)
684{
685 struct log_writes_c *lc = ti->private;
686
687 bio_set_dev(bio, lc->dev->bdev);
688}
689
690static int log_writes_map(struct dm_target *ti, struct bio *bio)
691{
692 struct log_writes_c *lc = ti->private;
693 struct per_bio_data *pb = dm_per_bio_data(bio, sizeof(struct per_bio_data));
694 struct pending_block *block;
695 struct bvec_iter iter;
696 struct bio_vec bv;
697 size_t alloc_size;
698 int i = 0;
699 bool flush_bio = (bio->bi_opf & REQ_PREFLUSH);
700 bool fua_bio = (bio->bi_opf & REQ_FUA);
701 bool discard_bio = (bio_op(bio) == REQ_OP_DISCARD);
702
703 pb->block = NULL;
704
705
706 if (!lc->logging_enabled)
707 goto map_bio;
708
709
710
711
712 if (bio_data_dir(bio) == READ)
713 goto map_bio;
714
715
716 if (!bio_sectors(bio) && !flush_bio)
717 goto map_bio;
718
719
720
721
722
723 if (discard_bio)
724 alloc_size = sizeof(struct pending_block);
725 else
726 alloc_size = sizeof(struct pending_block) + sizeof(struct bio_vec) * bio_segments(bio);
727
728 block = kzalloc(alloc_size, GFP_NOIO);
729 if (!block) {
730 DMERR("Error allocating pending block");
731 spin_lock_irq(&lc->blocks_lock);
732 lc->logging_enabled = false;
733 spin_unlock_irq(&lc->blocks_lock);
734 return DM_MAPIO_KILL;
735 }
736 INIT_LIST_HEAD(&block->list);
737 pb->block = block;
738 atomic_inc(&lc->pending_blocks);
739
740 if (flush_bio)
741 block->flags |= LOG_FLUSH_FLAG;
742 if (fua_bio)
743 block->flags |= LOG_FUA_FLAG;
744 if (discard_bio)
745 block->flags |= LOG_DISCARD_FLAG;
746
747 block->sector = bio_to_dev_sectors(lc, bio->bi_iter.bi_sector);
748 block->nr_sectors = bio_to_dev_sectors(lc, bio_sectors(bio));
749
750
751 if (discard_bio) {
752 WARN_ON(flush_bio || fua_bio);
753 if (lc->device_supports_discard)
754 goto map_bio;
755 bio_endio(bio);
756 return DM_MAPIO_SUBMITTED;
757 }
758
759
760 if (flush_bio && !bio_sectors(bio)) {
761 spin_lock_irq(&lc->blocks_lock);
762 list_splice_init(&lc->unflushed_blocks, &block->list);
763 spin_unlock_irq(&lc->blocks_lock);
764 goto map_bio;
765 }
766
767
768
769
770
771
772
773
774
775
776 bio_for_each_segment(bv, bio, iter) {
777 struct page *page;
778 void *src, *dst;
779
780 page = alloc_page(GFP_NOIO);
781 if (!page) {
782 DMERR("Error allocing page");
783 free_pending_block(lc, block);
784 spin_lock_irq(&lc->blocks_lock);
785 lc->logging_enabled = false;
786 spin_unlock_irq(&lc->blocks_lock);
787 return DM_MAPIO_KILL;
788 }
789
790 src = kmap_atomic(bv.bv_page);
791 dst = kmap_atomic(page);
792 memcpy(dst, src + bv.bv_offset, bv.bv_len);
793 kunmap_atomic(dst);
794 kunmap_atomic(src);
795 block->vecs[i].bv_page = page;
796 block->vecs[i].bv_len = bv.bv_len;
797 block->vec_cnt++;
798 i++;
799 }
800
801
802 if (flush_bio) {
803 spin_lock_irq(&lc->blocks_lock);
804 list_splice_init(&lc->unflushed_blocks, &block->list);
805 spin_unlock_irq(&lc->blocks_lock);
806 }
807map_bio:
808 normal_map_bio(ti, bio);
809 return DM_MAPIO_REMAPPED;
810}
811
812static int normal_end_io(struct dm_target *ti, struct bio *bio,
813 blk_status_t *error)
814{
815 struct log_writes_c *lc = ti->private;
816 struct per_bio_data *pb = dm_per_bio_data(bio, sizeof(struct per_bio_data));
817
818 if (bio_data_dir(bio) == WRITE && pb->block) {
819 struct pending_block *block = pb->block;
820 unsigned long flags;
821
822 spin_lock_irqsave(&lc->blocks_lock, flags);
823 if (block->flags & LOG_FLUSH_FLAG) {
824 list_splice_tail_init(&block->list, &lc->logging_blocks);
825 list_add_tail(&block->list, &lc->logging_blocks);
826 wake_up_process(lc->log_kthread);
827 } else if (block->flags & LOG_FUA_FLAG) {
828 list_add_tail(&block->list, &lc->logging_blocks);
829 wake_up_process(lc->log_kthread);
830 } else
831 list_add_tail(&block->list, &lc->unflushed_blocks);
832 spin_unlock_irqrestore(&lc->blocks_lock, flags);
833 }
834
835 return DM_ENDIO_DONE;
836}
837
838
839
840
841static void log_writes_status(struct dm_target *ti, status_type_t type,
842 unsigned status_flags, char *result,
843 unsigned maxlen)
844{
845 unsigned sz = 0;
846 struct log_writes_c *lc = ti->private;
847
848 switch (type) {
849 case STATUSTYPE_INFO:
850 DMEMIT("%llu %llu", lc->logged_entries,
851 (unsigned long long)lc->next_sector - 1);
852 if (!lc->logging_enabled)
853 DMEMIT(" logging_disabled");
854 break;
855
856 case STATUSTYPE_TABLE:
857 DMEMIT("%s %s", lc->dev->name, lc->logdev->name);
858 break;
859 }
860}
861
862static int log_writes_prepare_ioctl(struct dm_target *ti,
863 struct block_device **bdev, fmode_t *mode)
864{
865 struct log_writes_c *lc = ti->private;
866 struct dm_dev *dev = lc->dev;
867
868 *bdev = dev->bdev;
869
870
871
872 if (ti->len != i_size_read(dev->bdev->bd_inode) >> SECTOR_SHIFT)
873 return 1;
874 return 0;
875}
876
877static int log_writes_iterate_devices(struct dm_target *ti,
878 iterate_devices_callout_fn fn,
879 void *data)
880{
881 struct log_writes_c *lc = ti->private;
882
883 return fn(ti, lc->dev, 0, ti->len, data);
884}
885
886
887
888
889
890static int log_writes_message(struct dm_target *ti, unsigned argc, char **argv)
891{
892 int r = -EINVAL;
893 struct log_writes_c *lc = ti->private;
894
895 if (argc != 2) {
896 DMWARN("Invalid log-writes message arguments, expect 2 arguments, got %d", argc);
897 return r;
898 }
899
900 if (!strcasecmp(argv[0], "mark"))
901 r = log_mark(lc, argv[1]);
902 else
903 DMWARN("Unrecognised log writes target message received: %s", argv[0]);
904
905 return r;
906}
907
908static void log_writes_io_hints(struct dm_target *ti, struct queue_limits *limits)
909{
910 struct log_writes_c *lc = ti->private;
911 struct request_queue *q = bdev_get_queue(lc->dev->bdev);
912
913 if (!q || !blk_queue_discard(q)) {
914 lc->device_supports_discard = false;
915 limits->discard_granularity = lc->sectorsize;
916 limits->max_discard_sectors = (UINT_MAX >> SECTOR_SHIFT);
917 }
918 limits->logical_block_size = bdev_logical_block_size(lc->dev->bdev);
919 limits->physical_block_size = bdev_physical_block_size(lc->dev->bdev);
920 limits->io_min = limits->physical_block_size;
921}
922
923static long log_writes_dax_direct_access(struct dm_target *ti, pgoff_t pgoff,
924 long nr_pages, void **kaddr, pfn_t *pfn)
925{
926 struct log_writes_c *lc = ti->private;
927 sector_t sector = pgoff * PAGE_SECTORS;
928 int ret;
929
930 ret = bdev_dax_pgoff(lc->dev->bdev, sector, nr_pages * PAGE_SIZE, &pgoff);
931 if (ret)
932 return ret;
933 return dax_direct_access(lc->dev->dax_dev, pgoff, nr_pages, kaddr, pfn);
934}
935
936static size_t log_writes_dax_copy_from_iter(struct dm_target *ti,
937 pgoff_t pgoff, void *addr, size_t bytes,
938 struct iov_iter *i)
939{
940 struct log_writes_c *lc = ti->private;
941 sector_t sector = pgoff * PAGE_SECTORS;
942 int err;
943
944 if (bdev_dax_pgoff(lc->dev->bdev, sector, ALIGN(bytes, PAGE_SIZE), &pgoff))
945 return 0;
946
947
948 if (!lc->logging_enabled)
949 goto dax_copy;
950
951 err = log_dax(lc, sector, bytes, i);
952 if (err) {
953 DMWARN("Error %d logging DAX write", err);
954 return 0;
955 }
956dax_copy:
957 return dax_copy_from_iter(lc->dev->dax_dev, pgoff, addr, bytes, i);
958}
959
960static struct target_type log_writes_target = {
961 .name = "log-writes",
962 .version = {1, 1, 0},
963 .module = THIS_MODULE,
964 .ctr = log_writes_ctr,
965 .dtr = log_writes_dtr,
966 .map = log_writes_map,
967 .end_io = normal_end_io,
968 .status = log_writes_status,
969 .prepare_ioctl = log_writes_prepare_ioctl,
970 .message = log_writes_message,
971 .iterate_devices = log_writes_iterate_devices,
972 .io_hints = log_writes_io_hints,
973 .direct_access = log_writes_dax_direct_access,
974 .dax_copy_from_iter = log_writes_dax_copy_from_iter,
975};
976
977static int __init dm_log_writes_init(void)
978{
979 int r = dm_register_target(&log_writes_target);
980
981 if (r < 0)
982 DMERR("register failed %d", r);
983
984 return r;
985}
986
987static void __exit dm_log_writes_exit(void)
988{
989 dm_unregister_target(&log_writes_target);
990}
991
992module_init(dm_log_writes_init);
993module_exit(dm_log_writes_exit);
994
995MODULE_DESCRIPTION(DM_NAME " log writes target");
996MODULE_AUTHOR("Josef Bacik <jbacik@fb.com>");
997MODULE_LICENSE("GPL");
998