1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * Copyright (C) 2014 Facebook. All rights reserved.
4 *
5 * This file is released under the GPL.
6 */
7
8 #include <linux/device-mapper.h>
9
10 #include <linux/module.h>
11 #include <linux/init.h>
12 #include <linux/blkdev.h>
13 #include <linux/bio.h>
14 #include <linux/dax.h>
15 #include <linux/slab.h>
16 #include <linux/kthread.h>
17 #include <linux/freezer.h>
18 #include <linux/uio.h>
19
20 #define DM_MSG_PREFIX "log-writes"
21
22 /*
23 * This target will sequentially log all writes to the target device onto the
24 * log device. This is helpful for replaying writes to check for fs consistency
25 * at all times. This target provides a mechanism to mark specific events to
26 * check data at a later time. So for example you would:
27 *
28 * write data
29 * fsync
30 * dmsetup message /dev/whatever mark mymark
31 * unmount /mnt/test
32 *
33 * Then replay the log up to mymark and check the contents of the replay to
34 * verify it matches what was written.
35 *
36 * We log writes only after they have been flushed, this makes the log describe
37 * close to the order in which the data hits the actual disk, not its cache. So
38 * for example the following sequence (W means write, C means complete)
39 *
40 * Wa,Wb,Wc,Cc,Ca,FLUSH,FUAd,Cb,CFLUSH,CFUAd
41 *
42 * Would result in the log looking like this:
43 *
44 * c,a,b,flush,fuad,<other writes>,<next flush>
45 *
46 * This is meant to help expose problems where file systems do not properly wait
47 * on data being written before invoking a FLUSH. FUA bypasses cache so once it
48 * completes it is added to the log as it should be on disk.
49 *
50 * We treat DISCARDs as if they don't bypass cache so that they are logged in
51 * order of completion along with the normal writes. If we didn't do it this
52 * way we would process all the discards first and then write all the data, when
53 * in fact we want to do the data and the discard in the order that they
54 * completed.
55 */
56 #define LOG_FLUSH_FLAG (1 << 0)
57 #define LOG_FUA_FLAG (1 << 1)
58 #define LOG_DISCARD_FLAG (1 << 2)
59 #define LOG_MARK_FLAG (1 << 3)
60 #define LOG_METADATA_FLAG (1 << 4)
61
62 #define WRITE_LOG_VERSION 1ULL
63 #define WRITE_LOG_MAGIC 0x6a736677736872ULL
64 #define WRITE_LOG_SUPER_SECTOR 0
65
66 /*
67 * The disk format for this is braindead simple.
68 *
69 * At byte 0 we have our super, followed by the following sequence for
70 * nr_entries:
71 *
72 * [ 1 sector ][ entry->nr_sectors ]
73 * [log_write_entry][ data written ]
74 *
75 * The log_write_entry takes up a full sector so we can have arbitrary length
76 * marks and it leaves us room for extra content in the future.
77 */
78
79 /*
80 * Basic info about the log for userspace.
81 */
82 struct log_write_super {
83 __le64 magic;
84 __le64 version;
85 __le64 nr_entries;
86 __le32 sectorsize;
87 };
88
89 /*
90 * sector - the sector we wrote.
91 * nr_sectors - the number of sectors we wrote.
92 * flags - flags for this log entry.
93 * data_len - the size of the data in this log entry, this is for private log
94 * entry stuff, the MARK data provided by userspace for example.
95 */
96 struct log_write_entry {
97 __le64 sector;
98 __le64 nr_sectors;
99 __le64 flags;
100 __le64 data_len;
101 };
102
103 struct log_writes_c {
104 struct dm_dev *dev;
105 struct dm_dev *logdev;
106 u64 logged_entries;
107 u32 sectorsize;
108 u32 sectorshift;
109 atomic_t io_blocks;
110 atomic_t pending_blocks;
111 sector_t next_sector;
112 sector_t end_sector;
113 bool logging_enabled;
114 bool device_supports_discard;
115 spinlock_t blocks_lock;
116 struct list_head unflushed_blocks;
117 struct list_head logging_blocks;
118 wait_queue_head_t wait;
119 struct task_struct *log_kthread;
120 struct completion super_done;
121 };
122
123 struct pending_block {
124 int vec_cnt;
125 u64 flags;
126 sector_t sector;
127 sector_t nr_sectors;
128 char *data;
129 u32 datalen;
130 struct list_head list;
131 struct bio_vec vecs[];
132 };
133
134 struct per_bio_data {
135 struct pending_block *block;
136 };
137
bio_to_dev_sectors(struct log_writes_c * lc,sector_t sectors)138 static inline sector_t bio_to_dev_sectors(struct log_writes_c *lc,
139 sector_t sectors)
140 {
141 return sectors >> (lc->sectorshift - SECTOR_SHIFT);
142 }
143
dev_to_bio_sectors(struct log_writes_c * lc,sector_t sectors)144 static inline sector_t dev_to_bio_sectors(struct log_writes_c *lc,
145 sector_t sectors)
146 {
147 return sectors << (lc->sectorshift - SECTOR_SHIFT);
148 }
149
put_pending_block(struct log_writes_c * lc)150 static void put_pending_block(struct log_writes_c *lc)
151 {
152 if (atomic_dec_and_test(&lc->pending_blocks)) {
153 smp_mb__after_atomic();
154 if (waitqueue_active(&lc->wait))
155 wake_up(&lc->wait);
156 }
157 }
158
put_io_block(struct log_writes_c * lc)159 static void put_io_block(struct log_writes_c *lc)
160 {
161 if (atomic_dec_and_test(&lc->io_blocks)) {
162 smp_mb__after_atomic();
163 if (waitqueue_active(&lc->wait))
164 wake_up(&lc->wait);
165 }
166 }
167
log_end_io(struct bio * bio)168 static void log_end_io(struct bio *bio)
169 {
170 struct log_writes_c *lc = bio->bi_private;
171
172 if (bio->bi_status) {
173 unsigned long flags;
174
175 DMERR("Error writing log block, error=%d", bio->bi_status);
176 spin_lock_irqsave(&lc->blocks_lock, flags);
177 lc->logging_enabled = false;
178 spin_unlock_irqrestore(&lc->blocks_lock, flags);
179 }
180
181 bio_free_pages(bio);
182 put_io_block(lc);
183 bio_put(bio);
184 }
185
log_end_super(struct bio * bio)186 static void log_end_super(struct bio *bio)
187 {
188 struct log_writes_c *lc = bio->bi_private;
189
190 complete(&lc->super_done);
191 log_end_io(bio);
192 }
193
194 /*
195 * Meant to be called if there is an error, it will free all the pages
196 * associated with the block.
197 */
free_pending_block(struct log_writes_c * lc,struct pending_block * block)198 static void free_pending_block(struct log_writes_c *lc,
199 struct pending_block *block)
200 {
201 int i;
202
203 for (i = 0; i < block->vec_cnt; i++) {
204 if (block->vecs[i].bv_page)
205 __free_page(block->vecs[i].bv_page);
206 }
207 kfree(block->data);
208 kfree(block);
209 put_pending_block(lc);
210 }
211
write_metadata(struct log_writes_c * lc,void * entry,size_t entrylen,void * data,size_t datalen,sector_t sector)212 static int write_metadata(struct log_writes_c *lc, void *entry,
213 size_t entrylen, void *data, size_t datalen,
214 sector_t sector)
215 {
216 struct bio *bio;
217 struct page *page;
218 void *ptr;
219 size_t ret;
220
221 bio = bio_alloc(lc->logdev->bdev, 1, REQ_OP_WRITE, GFP_KERNEL);
222 bio->bi_iter.bi_size = 0;
223 bio->bi_iter.bi_sector = sector;
224 bio->bi_end_io = (sector == WRITE_LOG_SUPER_SECTOR) ?
225 log_end_super : log_end_io;
226 bio->bi_private = lc;
227
228 page = alloc_page(GFP_KERNEL);
229 if (!page) {
230 DMERR("Couldn't alloc log page");
231 bio_put(bio);
232 goto error;
233 }
234
235 ptr = kmap_local_page(page);
236 memcpy(ptr, entry, entrylen);
237 if (datalen)
238 memcpy(ptr + entrylen, data, datalen);
239 memset(ptr + entrylen + datalen, 0,
240 lc->sectorsize - entrylen - datalen);
241 kunmap_local(ptr);
242
243 ret = bio_add_page(bio, page, lc->sectorsize, 0);
244 if (ret != lc->sectorsize) {
245 DMERR("Couldn't add page to the log block");
246 goto error_bio;
247 }
248 submit_bio(bio);
249 return 0;
250 error_bio:
251 bio_put(bio);
252 __free_page(page);
253 error:
254 put_io_block(lc);
255 return -1;
256 }
257
write_inline_data(struct log_writes_c * lc,void * entry,size_t entrylen,void * data,size_t datalen,sector_t sector)258 static int write_inline_data(struct log_writes_c *lc, void *entry,
259 size_t entrylen, void *data, size_t datalen,
260 sector_t sector)
261 {
262 int bio_pages, pg_datalen, pg_sectorlen, i;
263 struct page *page;
264 struct bio *bio;
265 size_t ret;
266 void *ptr;
267
268 while (datalen) {
269 bio_pages = bio_max_segs(DIV_ROUND_UP(datalen, PAGE_SIZE));
270
271 atomic_inc(&lc->io_blocks);
272
273 bio = bio_alloc(lc->logdev->bdev, bio_pages, REQ_OP_WRITE,
274 GFP_KERNEL);
275 bio->bi_iter.bi_size = 0;
276 bio->bi_iter.bi_sector = sector;
277 bio->bi_end_io = log_end_io;
278 bio->bi_private = lc;
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_local_page(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_local(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;
311 error_bio:
312 bio_free_pages(bio);
313 bio_put(bio);
314 put_io_block(lc);
315 return -1;
316 }
317
log_one_block(struct log_writes_c * lc,struct pending_block * block,sector_t sector)318 static int log_one_block(struct log_writes_c *lc,
319 struct pending_block *block, sector_t sector)
320 {
321 struct bio *bio;
322 struct log_write_entry entry;
323 size_t metadatalen, ret;
324 int i;
325
326 entry.sector = cpu_to_le64(block->sector);
327 entry.nr_sectors = cpu_to_le64(block->nr_sectors);
328 entry.flags = cpu_to_le64(block->flags);
329 entry.data_len = cpu_to_le64(block->datalen);
330
331 metadatalen = (block->flags & LOG_MARK_FLAG) ? block->datalen : 0;
332 if (write_metadata(lc, &entry, sizeof(entry), block->data,
333 metadatalen, sector)) {
334 free_pending_block(lc, block);
335 return -1;
336 }
337
338 sector += dev_to_bio_sectors(lc, 1);
339
340 if (block->datalen && metadatalen == 0) {
341 if (write_inline_data(lc, &entry, sizeof(entry), block->data,
342 block->datalen, sector)) {
343 free_pending_block(lc, block);
344 return -1;
345 }
346 /* we don't support both inline data & bio data */
347 goto out;
348 }
349
350 if (!block->vec_cnt)
351 goto out;
352
353 atomic_inc(&lc->io_blocks);
354 bio = bio_alloc(lc->logdev->bdev, bio_max_segs(block->vec_cnt),
355 REQ_OP_WRITE, GFP_KERNEL);
356 bio->bi_iter.bi_size = 0;
357 bio->bi_iter.bi_sector = sector;
358 bio->bi_end_io = log_end_io;
359 bio->bi_private = lc;
360
361 for (i = 0; i < block->vec_cnt; i++) {
362 /*
363 * The page offset is always 0 because we allocate a new page
364 * for every bvec in the original bio for simplicity sake.
365 */
366 ret = bio_add_page(bio, block->vecs[i].bv_page,
367 block->vecs[i].bv_len, 0);
368 if (ret != block->vecs[i].bv_len) {
369 atomic_inc(&lc->io_blocks);
370 submit_bio(bio);
371 bio = bio_alloc(lc->logdev->bdev,
372 bio_max_segs(block->vec_cnt - i),
373 REQ_OP_WRITE, GFP_KERNEL);
374 bio->bi_iter.bi_size = 0;
375 bio->bi_iter.bi_sector = sector;
376 bio->bi_end_io = log_end_io;
377 bio->bi_private = lc;
378
379 ret = bio_add_page(bio, block->vecs[i].bv_page,
380 block->vecs[i].bv_len, 0);
381 if (ret != block->vecs[i].bv_len) {
382 DMERR("Couldn't add page on new bio?");
383 bio_put(bio);
384 goto error;
385 }
386 }
387 sector += block->vecs[i].bv_len >> SECTOR_SHIFT;
388 }
389 submit_bio(bio);
390 out:
391 kfree(block->data);
392 kfree(block);
393 put_pending_block(lc);
394 return 0;
395 error:
396 free_pending_block(lc, block);
397 put_io_block(lc);
398 return -1;
399 }
400
log_super(struct log_writes_c * lc)401 static int log_super(struct log_writes_c *lc)
402 {
403 struct log_write_super super;
404
405 super.magic = cpu_to_le64(WRITE_LOG_MAGIC);
406 super.version = cpu_to_le64(WRITE_LOG_VERSION);
407 super.nr_entries = cpu_to_le64(lc->logged_entries);
408 super.sectorsize = cpu_to_le32(lc->sectorsize);
409
410 if (write_metadata(lc, &super, sizeof(super), NULL, 0,
411 WRITE_LOG_SUPER_SECTOR)) {
412 DMERR("Couldn't write super");
413 return -1;
414 }
415
416 /*
417 * Super sector should be writen in-order, otherwise the
418 * nr_entries could be rewritten incorrectly by an old bio.
419 */
420 wait_for_completion_io(&lc->super_done);
421
422 return 0;
423 }
424
logdev_last_sector(struct log_writes_c * lc)425 static inline sector_t logdev_last_sector(struct log_writes_c *lc)
426 {
427 return bdev_nr_sectors(lc->logdev->bdev);
428 }
429
log_writes_kthread(void * arg)430 static int log_writes_kthread(void *arg)
431 {
432 struct log_writes_c *lc = arg;
433 sector_t sector = 0;
434
435 while (!kthread_should_stop()) {
436 bool super = false;
437 bool logging_enabled;
438 struct pending_block *block = NULL;
439 int ret;
440
441 spin_lock_irq(&lc->blocks_lock);
442 if (!list_empty(&lc->logging_blocks)) {
443 block = list_first_entry(&lc->logging_blocks,
444 struct pending_block, list);
445 list_del_init(&block->list);
446 if (!lc->logging_enabled)
447 goto next;
448
449 sector = lc->next_sector;
450 if (!(block->flags & LOG_DISCARD_FLAG))
451 lc->next_sector += dev_to_bio_sectors(lc, block->nr_sectors);
452 lc->next_sector += dev_to_bio_sectors(lc, 1);
453
454 /*
455 * Apparently the size of the device may not be known
456 * right away, so handle this properly.
457 */
458 if (!lc->end_sector)
459 lc->end_sector = logdev_last_sector(lc);
460 if (lc->end_sector &&
461 lc->next_sector >= lc->end_sector) {
462 DMERR("Ran out of space on the logdev");
463 lc->logging_enabled = false;
464 goto next;
465 }
466 lc->logged_entries++;
467 atomic_inc(&lc->io_blocks);
468
469 super = (block->flags & (LOG_FUA_FLAG | LOG_MARK_FLAG));
470 if (super)
471 atomic_inc(&lc->io_blocks);
472 }
473 next:
474 logging_enabled = lc->logging_enabled;
475 spin_unlock_irq(&lc->blocks_lock);
476 if (block) {
477 if (logging_enabled) {
478 ret = log_one_block(lc, block, sector);
479 if (!ret && super)
480 ret = log_super(lc);
481 if (ret) {
482 spin_lock_irq(&lc->blocks_lock);
483 lc->logging_enabled = false;
484 spin_unlock_irq(&lc->blocks_lock);
485 }
486 } else
487 free_pending_block(lc, block);
488 continue;
489 }
490
491 if (!try_to_freeze()) {
492 set_current_state(TASK_INTERRUPTIBLE);
493 if (!kthread_should_stop() &&
494 list_empty(&lc->logging_blocks))
495 schedule();
496 __set_current_state(TASK_RUNNING);
497 }
498 }
499 return 0;
500 }
501
502 /*
503 * Construct a log-writes mapping:
504 * log-writes <dev_path> <log_dev_path>
505 */
log_writes_ctr(struct dm_target * ti,unsigned int argc,char ** argv)506 static int log_writes_ctr(struct dm_target *ti, unsigned int argc, char **argv)
507 {
508 struct log_writes_c *lc;
509 struct dm_arg_set as;
510 const char *devname, *logdevname;
511 int ret;
512
513 as.argc = argc;
514 as.argv = argv;
515
516 if (argc < 2) {
517 ti->error = "Invalid argument count";
518 return -EINVAL;
519 }
520
521 lc = kzalloc(sizeof(struct log_writes_c), GFP_KERNEL);
522 if (!lc) {
523 ti->error = "Cannot allocate context";
524 return -ENOMEM;
525 }
526 spin_lock_init(&lc->blocks_lock);
527 INIT_LIST_HEAD(&lc->unflushed_blocks);
528 INIT_LIST_HEAD(&lc->logging_blocks);
529 init_waitqueue_head(&lc->wait);
530 init_completion(&lc->super_done);
531 atomic_set(&lc->io_blocks, 0);
532 atomic_set(&lc->pending_blocks, 0);
533
534 devname = dm_shift_arg(&as);
535 ret = dm_get_device(ti, devname, dm_table_get_mode(ti->table), &lc->dev);
536 if (ret) {
537 ti->error = "Device lookup failed";
538 goto bad;
539 }
540
541 logdevname = dm_shift_arg(&as);
542 ret = dm_get_device(ti, logdevname, dm_table_get_mode(ti->table),
543 &lc->logdev);
544 if (ret) {
545 ti->error = "Log device lookup failed";
546 dm_put_device(ti, lc->dev);
547 goto bad;
548 }
549
550 lc->sectorsize = bdev_logical_block_size(lc->dev->bdev);
551 lc->sectorshift = ilog2(lc->sectorsize);
552 lc->log_kthread = kthread_run(log_writes_kthread, lc, "log-write");
553 if (IS_ERR(lc->log_kthread)) {
554 ret = PTR_ERR(lc->log_kthread);
555 ti->error = "Couldn't alloc kthread";
556 dm_put_device(ti, lc->dev);
557 dm_put_device(ti, lc->logdev);
558 goto bad;
559 }
560
561 /*
562 * next_sector is in 512b sectors to correspond to what bi_sector expects.
563 * The super starts at sector 0, and the next_sector is the next logical
564 * one based on the sectorsize of the device.
565 */
566 lc->next_sector = lc->sectorsize >> SECTOR_SHIFT;
567 lc->logging_enabled = true;
568 lc->end_sector = logdev_last_sector(lc);
569 lc->device_supports_discard = true;
570
571 ti->num_flush_bios = 1;
572 ti->flush_supported = true;
573 ti->num_discard_bios = 1;
574 ti->discards_supported = true;
575 ti->per_io_data_size = sizeof(struct per_bio_data);
576 ti->private = lc;
577 return 0;
578
579 bad:
580 kfree(lc);
581 return ret;
582 }
583
log_mark(struct log_writes_c * lc,char * data)584 static int log_mark(struct log_writes_c *lc, char *data)
585 {
586 struct pending_block *block;
587 size_t maxsize = lc->sectorsize - sizeof(struct log_write_entry);
588
589 block = kzalloc(sizeof(struct pending_block), GFP_KERNEL);
590 if (!block) {
591 DMERR("Error allocating pending block");
592 return -ENOMEM;
593 }
594
595 block->data = kstrndup(data, maxsize - 1, GFP_KERNEL);
596 if (!block->data) {
597 DMERR("Error copying mark data");
598 kfree(block);
599 return -ENOMEM;
600 }
601 atomic_inc(&lc->pending_blocks);
602 block->datalen = strlen(block->data);
603 block->flags |= LOG_MARK_FLAG;
604 spin_lock_irq(&lc->blocks_lock);
605 list_add_tail(&block->list, &lc->logging_blocks);
606 spin_unlock_irq(&lc->blocks_lock);
607 wake_up_process(lc->log_kthread);
608 return 0;
609 }
610
log_writes_dtr(struct dm_target * ti)611 static void log_writes_dtr(struct dm_target *ti)
612 {
613 struct log_writes_c *lc = ti->private;
614
615 spin_lock_irq(&lc->blocks_lock);
616 list_splice_init(&lc->unflushed_blocks, &lc->logging_blocks);
617 spin_unlock_irq(&lc->blocks_lock);
618
619 /*
620 * This is just nice to have since it'll update the super to include the
621 * unflushed blocks, if it fails we don't really care.
622 */
623 log_mark(lc, "dm-log-writes-end");
624 wake_up_process(lc->log_kthread);
625 wait_event(lc->wait, !atomic_read(&lc->io_blocks) &&
626 !atomic_read(&lc->pending_blocks));
627 kthread_stop(lc->log_kthread);
628
629 WARN_ON(!list_empty(&lc->logging_blocks));
630 WARN_ON(!list_empty(&lc->unflushed_blocks));
631 dm_put_device(ti, lc->dev);
632 dm_put_device(ti, lc->logdev);
633 kfree(lc);
634 }
635
normal_map_bio(struct dm_target * ti,struct bio * bio)636 static void normal_map_bio(struct dm_target *ti, struct bio *bio)
637 {
638 struct log_writes_c *lc = ti->private;
639
640 bio_set_dev(bio, lc->dev->bdev);
641 }
642
log_writes_map(struct dm_target * ti,struct bio * bio)643 static int log_writes_map(struct dm_target *ti, struct bio *bio)
644 {
645 struct log_writes_c *lc = ti->private;
646 struct per_bio_data *pb = dm_per_bio_data(bio, sizeof(struct per_bio_data));
647 struct pending_block *block;
648 struct bvec_iter iter;
649 struct bio_vec bv;
650 size_t alloc_size;
651 int i = 0;
652 bool flush_bio = (bio->bi_opf & REQ_PREFLUSH);
653 bool fua_bio = (bio->bi_opf & REQ_FUA);
654 bool discard_bio = (bio_op(bio) == REQ_OP_DISCARD);
655 bool meta_bio = (bio->bi_opf & REQ_META);
656
657 pb->block = NULL;
658
659 /* Don't bother doing anything if logging has been disabled */
660 if (!lc->logging_enabled)
661 goto map_bio;
662
663 /*
664 * Map reads as normal.
665 */
666 if (bio_data_dir(bio) == READ)
667 goto map_bio;
668
669 /* No sectors and not a flush? Don't care */
670 if (!bio_sectors(bio) && !flush_bio)
671 goto map_bio;
672
673 /*
674 * Discards will have bi_size set but there's no actual data, so just
675 * allocate the size of the pending block.
676 */
677 if (discard_bio)
678 alloc_size = sizeof(struct pending_block);
679 else
680 alloc_size = struct_size(block, vecs, bio_segments(bio));
681
682 block = kzalloc(alloc_size, GFP_NOIO);
683 if (!block) {
684 DMERR("Error allocating pending block");
685 spin_lock_irq(&lc->blocks_lock);
686 lc->logging_enabled = false;
687 spin_unlock_irq(&lc->blocks_lock);
688 return DM_MAPIO_KILL;
689 }
690 INIT_LIST_HEAD(&block->list);
691 pb->block = block;
692 atomic_inc(&lc->pending_blocks);
693
694 if (flush_bio)
695 block->flags |= LOG_FLUSH_FLAG;
696 if (fua_bio)
697 block->flags |= LOG_FUA_FLAG;
698 if (discard_bio)
699 block->flags |= LOG_DISCARD_FLAG;
700 if (meta_bio)
701 block->flags |= LOG_METADATA_FLAG;
702
703 block->sector = bio_to_dev_sectors(lc, bio->bi_iter.bi_sector);
704 block->nr_sectors = bio_to_dev_sectors(lc, bio_sectors(bio));
705
706 /* We don't need the data, just submit */
707 if (discard_bio) {
708 WARN_ON(flush_bio || fua_bio);
709 if (lc->device_supports_discard)
710 goto map_bio;
711 bio_endio(bio);
712 return DM_MAPIO_SUBMITTED;
713 }
714
715 /* Flush bio, splice the unflushed blocks onto this list and submit */
716 if (flush_bio && !bio_sectors(bio)) {
717 spin_lock_irq(&lc->blocks_lock);
718 list_splice_init(&lc->unflushed_blocks, &block->list);
719 spin_unlock_irq(&lc->blocks_lock);
720 goto map_bio;
721 }
722
723 /*
724 * We will write this bio somewhere else way later so we need to copy
725 * the actual contents into new pages so we know the data will always be
726 * there.
727 *
728 * We do this because this could be a bio from O_DIRECT in which case we
729 * can't just hold onto the page until some later point, we have to
730 * manually copy the contents.
731 */
732 bio_for_each_segment(bv, bio, iter) {
733 struct page *page;
734 void *dst;
735
736 page = alloc_page(GFP_NOIO);
737 if (!page) {
738 DMERR("Error allocing page");
739 free_pending_block(lc, block);
740 spin_lock_irq(&lc->blocks_lock);
741 lc->logging_enabled = false;
742 spin_unlock_irq(&lc->blocks_lock);
743 return DM_MAPIO_KILL;
744 }
745
746 dst = kmap_local_page(page);
747 memcpy_from_bvec(dst, &bv);
748 kunmap_local(dst);
749 block->vecs[i].bv_page = page;
750 block->vecs[i].bv_len = bv.bv_len;
751 block->vec_cnt++;
752 i++;
753 }
754
755 /* Had a flush with data in it, weird */
756 if (flush_bio) {
757 spin_lock_irq(&lc->blocks_lock);
758 list_splice_init(&lc->unflushed_blocks, &block->list);
759 spin_unlock_irq(&lc->blocks_lock);
760 }
761 map_bio:
762 normal_map_bio(ti, bio);
763 return DM_MAPIO_REMAPPED;
764 }
765
normal_end_io(struct dm_target * ti,struct bio * bio,blk_status_t * error)766 static int normal_end_io(struct dm_target *ti, struct bio *bio,
767 blk_status_t *error)
768 {
769 struct log_writes_c *lc = ti->private;
770 struct per_bio_data *pb = dm_per_bio_data(bio, sizeof(struct per_bio_data));
771
772 if (bio_data_dir(bio) == WRITE && pb->block) {
773 struct pending_block *block = pb->block;
774 unsigned long flags;
775
776 spin_lock_irqsave(&lc->blocks_lock, flags);
777 if (block->flags & LOG_FLUSH_FLAG) {
778 list_splice_tail_init(&block->list, &lc->logging_blocks);
779 list_add_tail(&block->list, &lc->logging_blocks);
780 wake_up_process(lc->log_kthread);
781 } else if (block->flags & LOG_FUA_FLAG) {
782 list_add_tail(&block->list, &lc->logging_blocks);
783 wake_up_process(lc->log_kthread);
784 } else
785 list_add_tail(&block->list, &lc->unflushed_blocks);
786 spin_unlock_irqrestore(&lc->blocks_lock, flags);
787 }
788
789 return DM_ENDIO_DONE;
790 }
791
792 /*
793 * INFO format: <logged entries> <highest allocated sector>
794 */
log_writes_status(struct dm_target * ti,status_type_t type,unsigned int status_flags,char * result,unsigned int maxlen)795 static void log_writes_status(struct dm_target *ti, status_type_t type,
796 unsigned int status_flags, char *result,
797 unsigned int maxlen)
798 {
799 unsigned int sz = 0;
800 struct log_writes_c *lc = ti->private;
801
802 switch (type) {
803 case STATUSTYPE_INFO:
804 DMEMIT("%llu %llu", lc->logged_entries,
805 (unsigned long long)lc->next_sector - 1);
806 if (!lc->logging_enabled)
807 DMEMIT(" logging_disabled");
808 break;
809
810 case STATUSTYPE_TABLE:
811 DMEMIT("%s %s", lc->dev->name, lc->logdev->name);
812 break;
813
814 case STATUSTYPE_IMA:
815 *result = '\0';
816 break;
817 }
818 }
819
log_writes_prepare_ioctl(struct dm_target * ti,struct block_device ** bdev)820 static int log_writes_prepare_ioctl(struct dm_target *ti,
821 struct block_device **bdev)
822 {
823 struct log_writes_c *lc = ti->private;
824 struct dm_dev *dev = lc->dev;
825
826 *bdev = dev->bdev;
827 /*
828 * Only pass ioctls through if the device sizes match exactly.
829 */
830 if (ti->len != bdev_nr_sectors(dev->bdev))
831 return 1;
832 return 0;
833 }
834
log_writes_iterate_devices(struct dm_target * ti,iterate_devices_callout_fn fn,void * data)835 static int log_writes_iterate_devices(struct dm_target *ti,
836 iterate_devices_callout_fn fn,
837 void *data)
838 {
839 struct log_writes_c *lc = ti->private;
840
841 return fn(ti, lc->dev, 0, ti->len, data);
842 }
843
844 /*
845 * Messages supported:
846 * mark <mark data> - specify the marked data.
847 */
log_writes_message(struct dm_target * ti,unsigned int argc,char ** argv,char * result,unsigned int maxlen)848 static int log_writes_message(struct dm_target *ti, unsigned int argc, char **argv,
849 char *result, unsigned int maxlen)
850 {
851 int r = -EINVAL;
852 struct log_writes_c *lc = ti->private;
853
854 if (argc != 2) {
855 DMWARN("Invalid log-writes message arguments, expect 2 arguments, got %d", argc);
856 return r;
857 }
858
859 if (!strcasecmp(argv[0], "mark"))
860 r = log_mark(lc, argv[1]);
861 else
862 DMWARN("Unrecognised log writes target message received: %s", argv[0]);
863
864 return r;
865 }
866
log_writes_io_hints(struct dm_target * ti,struct queue_limits * limits)867 static void log_writes_io_hints(struct dm_target *ti, struct queue_limits *limits)
868 {
869 struct log_writes_c *lc = ti->private;
870
871 if (!bdev_max_discard_sectors(lc->dev->bdev)) {
872 lc->device_supports_discard = false;
873 limits->discard_granularity = lc->sectorsize;
874 limits->max_discard_sectors = (UINT_MAX >> SECTOR_SHIFT);
875 }
876 limits->logical_block_size = bdev_logical_block_size(lc->dev->bdev);
877 limits->physical_block_size = bdev_physical_block_size(lc->dev->bdev);
878 limits->io_min = limits->physical_block_size;
879 limits->dma_alignment = limits->logical_block_size - 1;
880 }
881
882 #if IS_ENABLED(CONFIG_FS_DAX)
log_writes_dax_pgoff(struct dm_target * ti,pgoff_t * pgoff)883 static struct dax_device *log_writes_dax_pgoff(struct dm_target *ti,
884 pgoff_t *pgoff)
885 {
886 struct log_writes_c *lc = ti->private;
887
888 *pgoff += (get_start_sect(lc->dev->bdev) >> PAGE_SECTORS_SHIFT);
889 return lc->dev->dax_dev;
890 }
891
log_writes_dax_direct_access(struct dm_target * ti,pgoff_t pgoff,long nr_pages,enum dax_access_mode mode,void ** kaddr,pfn_t * pfn)892 static long log_writes_dax_direct_access(struct dm_target *ti, pgoff_t pgoff,
893 long nr_pages, enum dax_access_mode mode, void **kaddr,
894 pfn_t *pfn)
895 {
896 struct dax_device *dax_dev = log_writes_dax_pgoff(ti, &pgoff);
897
898 return dax_direct_access(dax_dev, pgoff, nr_pages, mode, kaddr, pfn);
899 }
900
log_writes_dax_zero_page_range(struct dm_target * ti,pgoff_t pgoff,size_t nr_pages)901 static int log_writes_dax_zero_page_range(struct dm_target *ti, pgoff_t pgoff,
902 size_t nr_pages)
903 {
904 struct dax_device *dax_dev = log_writes_dax_pgoff(ti, &pgoff);
905
906 return dax_zero_page_range(dax_dev, pgoff, nr_pages << PAGE_SHIFT);
907 }
908
log_writes_dax_recovery_write(struct dm_target * ti,pgoff_t pgoff,void * addr,size_t bytes,struct iov_iter * i)909 static size_t log_writes_dax_recovery_write(struct dm_target *ti,
910 pgoff_t pgoff, void *addr, size_t bytes, struct iov_iter *i)
911 {
912 struct dax_device *dax_dev = log_writes_dax_pgoff(ti, &pgoff);
913
914 return dax_recovery_write(dax_dev, pgoff, addr, bytes, i);
915 }
916
917 #else
918 #define log_writes_dax_direct_access NULL
919 #define log_writes_dax_zero_page_range NULL
920 #define log_writes_dax_recovery_write NULL
921 #endif
922
923 static struct target_type log_writes_target = {
924 .name = "log-writes",
925 .version = {1, 1, 0},
926 .module = THIS_MODULE,
927 .ctr = log_writes_ctr,
928 .dtr = log_writes_dtr,
929 .map = log_writes_map,
930 .end_io = normal_end_io,
931 .status = log_writes_status,
932 .prepare_ioctl = log_writes_prepare_ioctl,
933 .message = log_writes_message,
934 .iterate_devices = log_writes_iterate_devices,
935 .io_hints = log_writes_io_hints,
936 .direct_access = log_writes_dax_direct_access,
937 .dax_zero_page_range = log_writes_dax_zero_page_range,
938 .dax_recovery_write = log_writes_dax_recovery_write,
939 };
940 module_dm(log_writes);
941
942 MODULE_DESCRIPTION(DM_NAME " log writes target");
943 MODULE_AUTHOR("Josef Bacik <jbacik@fb.com>");
944 MODULE_LICENSE("GPL");
945