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2024-05-14 bedbef8ad3e75a304af6361af235302bcc61d06b 
 kernel/fs/btrfs/dev-replace.c
....@@ -9,6 +9,7 @@
99 #include <linux/blkdev.h>
1010 #include <linux/kthread.h>
1111 #include <linux/math64.h>
12
+#include "misc.h"
1213 #include "ctree.h"
1314 #include "extent_map.h"
1415 #include "disk-io.h"
....@@ -21,12 +22,48 @@
2122 #include "dev-replace.h"
2223 #include "sysfs.h"
2324 
25
+/*
26
+ * Device replace overview
27
+ *
28
+ * [Objective]
29
+ * To copy all extents (both new and on-disk) from source device to target
30
+ * device, while still keeping the filesystem read-write.
31
+ *
32
+ * [Method]
33
+ * There are two main methods involved:
34
+ *
35
+ * - Write duplication
36
+ *
37
+ *   All new writes will be written to both target and source devices, so even
38
+ *   if replace gets canceled, sources device still contans up-to-date data.
39
+ *
40
+ *   Location:		handle_ops_on_dev_replace() from __btrfs_map_block()
41
+ *   Start:		btrfs_dev_replace_start()
42
+ *   End:		btrfs_dev_replace_finishing()
43
+ *   Content:		Latest data/metadata
44
+ *
45
+ * - Copy existing extents
46
+ *
47
+ *   This happens by re-using scrub facility, as scrub also iterates through
48
+ *   existing extents from commit root.
49
+ *
50
+ *   Location:		scrub_write_block_to_dev_replace() from
51
+ *   			scrub_block_complete()
52
+ *   Content:		Data/meta from commit root.
53
+ *
54
+ * Due to the content difference, we need to avoid nocow write when dev-replace
55
+ * is happening.  This is done by marking the block group read-only and waiting
56
+ * for NOCOW writes.
57
+ *
58
+ * After replace is done, the finishing part is done by swapping the target and
59
+ * source devices.
60
+ *
61
+ *   Location:		btrfs_dev_replace_update_device_in_mapping_tree() from
62
+ *   			btrfs_dev_replace_finishing()
63
+ */
64
+
2465 static int btrfs_dev_replace_finishing(struct btrfs_fs_info *fs_info,
2566 				       int scrub_ret);
26
-static void btrfs_dev_replace_update_device_in_mapping_tree(
27
-						struct btrfs_fs_info *fs_info,
28
-						struct btrfs_device *srcdev,
29
-						struct btrfs_device *tgtdev);
3067 static int btrfs_dev_replace_kthread(void *data);
3168 
3269 int btrfs_init_dev_replace(struct btrfs_fs_info *fs_info)
....@@ -67,10 +104,9 @@
67104 		}
68105 		ret = 0;
69106 		dev_replace->replace_state =
70
-			BTRFS_DEV_REPLACE_ITEM_STATE_NEVER_STARTED;
107
+			BTRFS_IOCTL_DEV_REPLACE_STATE_NEVER_STARTED;
71108 		dev_replace->cont_reading_from_srcdev_mode =
72109 		    BTRFS_DEV_REPLACE_ITEM_CONT_READING_FROM_SRCDEV_MODE_ALWAYS;
73
-		dev_replace->replace_state = 0;
74110 		dev_replace->time_started = 0;
75111 		dev_replace->time_stopped = 0;
76112 		atomic64_set(&dev_replace->num_write_errors, 0);
....@@ -125,7 +161,7 @@
125161 		if (btrfs_find_device(fs_info->fs_devices,
126162 				      BTRFS_DEV_REPLACE_DEVID, NULL, NULL, false)) {
127163 			btrfs_err(fs_info,
128
-			"replace devid present without an active replace item");
164
+"replace without active item, run 'device scan --forget' on the target device");
129165 			ret = -EUCLEAN;
130166 		} else {
131167 			dev_replace->srcdev = NULL;
....@@ -206,7 +242,6 @@
206242 {
207243 	struct btrfs_device *device;
208244 	struct block_device *bdev;
209
-	struct list_head *devices;
210245 	struct rcu_string *name;
211246 	u64 devid = BTRFS_DEV_REPLACE_DEVID;
212247 	int ret = 0;
....@@ -224,10 +259,9 @@
224259 		return PTR_ERR(bdev);
225260 	}
226261 
227
-	filemap_write_and_wait(bdev->bd_inode->i_mapping);
262
+	sync_blockdev(bdev);
228263 
229
-	devices = &fs_info->fs_devices->devices;
230
-	list_for_each_entry(device, devices, dev_list) {
264
+	list_for_each_entry(device, &fs_info->fs_devices->devices, dev_list) {
231265 		if (device->bdev == bdev) {
232266 			btrfs_err(fs_info,
233267 				  "target device is in the filesystem!");
....@@ -260,7 +294,6 @@
260294 	}
261295 	rcu_assign_pointer(device->name, name);
262296 
263
-	mutex_lock(&fs_info->fs_devices->device_list_mutex);
264297 	set_bit(BTRFS_DEV_STATE_WRITEABLE, &device->dev_state);
265298 	device->generation = 0;
266299 	device->io_width = fs_info->sectorsize;
....@@ -279,6 +312,8 @@
279312 	device->dev_stats_valid = 1;
280313 	set_blocksize(device->bdev, BTRFS_BDEV_BLOCKSIZE);
281314 	device->fs_devices = fs_info->fs_devices;
315
+
316
+	mutex_lock(&fs_info->fs_devices->device_list_mutex);
282317 	list_add(&device->dev_list, &fs_info->fs_devices->devices);
283318 	fs_info->fs_devices->num_devices++;
284319 	fs_info->fs_devices->open_devices++;
....@@ -296,9 +331,9 @@
296331  * called from commit_transaction. Writes changed device replace state to
297332  * disk.
298333  */
299
-int btrfs_run_dev_replace(struct btrfs_trans_handle *trans,
300
-			  struct btrfs_fs_info *fs_info)
334
+int btrfs_run_dev_replace(struct btrfs_trans_handle *trans)
301335 {
336
+	struct btrfs_fs_info *fs_info = trans->fs_info;
302337 	int ret;
303338 	struct btrfs_root *dev_root = fs_info->dev_root;
304339 	struct btrfs_path *path;
....@@ -307,13 +342,13 @@
307342 	struct btrfs_dev_replace_item *ptr;
308343 	struct btrfs_dev_replace *dev_replace = &fs_info->dev_replace;
309344 
310
-	btrfs_dev_replace_read_lock(dev_replace);
345
+	down_read(&dev_replace->rwsem);
311346 	if (!dev_replace->is_valid ||
312347 	    !dev_replace->item_needs_writeback) {
313
-		btrfs_dev_replace_read_unlock(dev_replace);
348
+		up_read(&dev_replace->rwsem);
314349 		return 0;
315350 	}
316
-	btrfs_dev_replace_read_unlock(dev_replace);
351
+	up_read(&dev_replace->rwsem);
317352 
318353 	key.objectid = 0;
319354 	key.type = BTRFS_DEV_REPLACE_KEY;
....@@ -371,7 +406,7 @@
371406 	ptr = btrfs_item_ptr(eb, path->slots[0],
372407 			     struct btrfs_dev_replace_item);
373408 
374
-	btrfs_dev_replace_write_lock(dev_replace);
409
+	down_write(&dev_replace->rwsem);
375410 	if (dev_replace->srcdev)
376411 		btrfs_set_dev_replace_src_devid(eb, ptr,
377412 			dev_replace->srcdev->devid);
....@@ -394,7 +429,7 @@
394429 	btrfs_set_dev_replace_cursor_right(eb, ptr,
395430 		dev_replace->cursor_right);
396431 	dev_replace->item_needs_writeback = 0;
397
-	btrfs_dev_replace_write_unlock(dev_replace);
432
+	up_write(&dev_replace->rwsem);
398433 
399434 	btrfs_mark_buffer_dirty(eb);
400435 
....@@ -402,14 +437,6 @@
402437 	btrfs_free_path(path);
403438 
404439 	return ret;
405
-}
406
-
407
-void btrfs_after_dev_replace_commit(struct btrfs_fs_info *fs_info)
408
-{
409
-	struct btrfs_dev_replace *dev_replace = &fs_info->dev_replace;
410
-
411
-	dev_replace->committed_cursor_left =
412
-		dev_replace->cursor_left_last_write_of_item;
413440 }
414441 
415442 static char* btrfs_dev_name(struct btrfs_device *device)
....@@ -420,7 +447,7 @@
420447 		return rcu_str_deref(device->name);
421448 }
422449 
423
-int btrfs_dev_replace_start(struct btrfs_fs_info *fs_info,
450
+static int btrfs_dev_replace_start(struct btrfs_fs_info *fs_info,
424451 		const char *tgtdev_name, u64 srcdevid, const char *srcdev_name,
425452 		int read_src)
426453 {
....@@ -431,15 +458,17 @@
431458 	struct btrfs_device *tgt_device = NULL;
432459 	struct btrfs_device *src_device = NULL;
433460 
434
-	ret = btrfs_find_device_by_devspec(fs_info, srcdevid,
435
-					    srcdev_name, &src_device);
436
-	if (ret)
437
-		return ret;
461
+	src_device = btrfs_find_device_by_devspec(fs_info, srcdevid,
462
+						  srcdev_name);
463
+	if (IS_ERR(src_device))
464
+		return PTR_ERR(src_device);
438465 
439
-	ret = btrfs_init_dev_replace_tgtdev(fs_info, tgtdev_name,
440
-					    src_device, &tgt_device);
441
-	if (ret)
442
-		return ret;
466
+	if (btrfs_pinned_by_swapfile(fs_info, src_device)) {
467
+		btrfs_warn_in_rcu(fs_info,
468
+	  "cannot replace device %s (devid %llu) due to active swapfile",
469
+			btrfs_dev_name(src_device), src_device->devid);
470
+		return -ETXTBSY;
471
+	}
443472 
444473 	/*
445474 	 * Here we commit the transaction to make sure commit_total_bytes
....@@ -454,7 +483,12 @@
454483 		return PTR_ERR(trans);
455484 	}
456485 
457
-	btrfs_dev_replace_write_lock(dev_replace);
486
+	ret = btrfs_init_dev_replace_tgtdev(fs_info, tgtdev_name,
487
+					    src_device, &tgt_device);
488
+	if (ret)
489
+		return ret;
490
+
491
+	down_write(&dev_replace->rwsem);
458492 	switch (dev_replace->replace_state) {
459493 	case BTRFS_IOCTL_DEV_REPLACE_STATE_NEVER_STARTED:
460494 	case BTRFS_IOCTL_DEV_REPLACE_STATE_FINISHED:
....@@ -464,11 +498,11 @@
464498 	case BTRFS_IOCTL_DEV_REPLACE_STATE_SUSPENDED:
465499 		ASSERT(0);
466500 		ret = BTRFS_IOCTL_DEV_REPLACE_RESULT_ALREADY_STARTED;
501
+		up_write(&dev_replace->rwsem);
467502 		goto leave;
468503 	}
469504 
470505 	dev_replace->cont_reading_from_srcdev_mode = read_src;
471
-	WARN_ON(!src_device);
472506 	dev_replace->srcdev = src_device;
473507 	dev_replace->tgtdev = tgt_device;
474508 
....@@ -492,23 +526,24 @@
492526 	dev_replace->item_needs_writeback = 1;
493527 	atomic64_set(&dev_replace->num_write_errors, 0);
494528 	atomic64_set(&dev_replace->num_uncorrectable_read_errors, 0);
495
-	btrfs_dev_replace_write_unlock(dev_replace);
529
+	up_write(&dev_replace->rwsem);
496530 
497
-	ret = btrfs_sysfs_add_device_link(tgt_device->fs_devices, tgt_device);
531
+	ret = btrfs_sysfs_add_device(tgt_device);
498532 	if (ret)
499533 		btrfs_err(fs_info, "kobj add dev failed %d", ret);
500534 
501535 	btrfs_wait_ordered_roots(fs_info, U64_MAX, 0, (u64)-1);
502536 
503
-	/* force writing the updated state information to disk */
504
-	trans = btrfs_start_transaction(root, 0);
537
+	/* Commit dev_replace state and reserve 1 item for it. */
538
+	trans = btrfs_start_transaction(root, 1);
505539 	if (IS_ERR(trans)) {
506540 		ret = PTR_ERR(trans);
507
-		btrfs_dev_replace_write_lock(dev_replace);
541
+		down_write(&dev_replace->rwsem);
508542 		dev_replace->replace_state =
509543 			BTRFS_IOCTL_DEV_REPLACE_STATE_NEVER_STARTED;
510544 		dev_replace->srcdev = NULL;
511545 		dev_replace->tgtdev = NULL;
546
+		up_write(&dev_replace->rwsem);
512547 		goto leave;
513548 	}
514549 
....@@ -521,16 +556,12 @@
521556 			      &dev_replace->scrub_progress, 0, 1);
522557 
523558 	ret = btrfs_dev_replace_finishing(fs_info, ret);
524
-	if (ret == -EINPROGRESS) {
559
+	if (ret == -EINPROGRESS)
525560 		ret = BTRFS_IOCTL_DEV_REPLACE_RESULT_SCRUB_INPROGRESS;
526
-	} else {
527
-		WARN_ON(ret);
528
-	}
529561 
530562 	return ret;
531563 
532564 leave:
533
-	btrfs_dev_replace_write_unlock(dev_replace);
534565 	btrfs_destroy_dev_replace_tgtdev(tgt_device);
535566 	return ret;
536567 }
....@@ -558,8 +589,9 @@
558589 					args->start.cont_reading_from_srcdev_mode);
559590 	args->result = ret;
560591 	/* don't warn if EINPROGRESS, someone else might be running scrub */
561
-	if (ret == BTRFS_IOCTL_DEV_REPLACE_RESULT_SCRUB_INPROGRESS)
562
-		ret = 0;
592
+	if (ret == BTRFS_IOCTL_DEV_REPLACE_RESULT_SCRUB_INPROGRESS ||
593
+	    ret == BTRFS_IOCTL_DEV_REPLACE_RESULT_NO_ERROR)
594
+		return 0;
563595 
564596 	return ret;
565597 }
....@@ -570,8 +602,8 @@
570602 static void btrfs_rm_dev_replace_blocked(struct btrfs_fs_info *fs_info)
571603 {
572604 	set_bit(BTRFS_FS_STATE_DEV_REPLACING, &fs_info->fs_state);
573
-	wait_event(fs_info->replace_wait, !percpu_counter_sum(
574
-		   &fs_info->bio_counter));
605
+	wait_event(fs_info->dev_replace.replace_wait, !percpu_counter_sum(
606
+		   &fs_info->dev_replace.bio_counter));
575607 }
576608 
577609 /*
....@@ -580,7 +612,64 @@
580612 static void btrfs_rm_dev_replace_unblocked(struct btrfs_fs_info *fs_info)
581613 {
582614 	clear_bit(BTRFS_FS_STATE_DEV_REPLACING, &fs_info->fs_state);
583
-	wake_up(&fs_info->replace_wait);
615
+	wake_up(&fs_info->dev_replace.replace_wait);
616
+}
617
+
618
+/*
619
+ * When finishing the device replace, before swapping the source device with the
620
+ * target device we must update the chunk allocation state in the target device,
621
+ * as it is empty because replace works by directly copying the chunks and not
622
+ * through the normal chunk allocation path.
623
+ */
624
+static int btrfs_set_target_alloc_state(struct btrfs_device *srcdev,
625
+					struct btrfs_device *tgtdev)
626
+{
627
+	struct extent_state *cached_state = NULL;
628
+	u64 start = 0;
629
+	u64 found_start;
630
+	u64 found_end;
631
+	int ret = 0;
632
+
633
+	lockdep_assert_held(&srcdev->fs_info->chunk_mutex);
634
+
635
+	while (!find_first_extent_bit(&srcdev->alloc_state, start,
636
+				      &found_start, &found_end,
637
+				      CHUNK_ALLOCATED, &cached_state)) {
638
+		ret = set_extent_bits(&tgtdev->alloc_state, found_start,
639
+				      found_end, CHUNK_ALLOCATED);
640
+		if (ret)
641
+			break;
642
+		start = found_end + 1;
643
+	}
644
+
645
+	free_extent_state(cached_state);
646
+	return ret;
647
+}
648
+
649
+static void btrfs_dev_replace_update_device_in_mapping_tree(
650
+						struct btrfs_fs_info *fs_info,
651
+						struct btrfs_device *srcdev,
652
+						struct btrfs_device *tgtdev)
653
+{
654
+	struct extent_map_tree *em_tree = &fs_info->mapping_tree;
655
+	struct extent_map *em;
656
+	struct map_lookup *map;
657
+	u64 start = 0;
658
+	int i;
659
+
660
+	write_lock(&em_tree->lock);
661
+	do {
662
+		em = lookup_extent_mapping(em_tree, start, (u64)-1);
663
+		if (!em)
664
+			break;
665
+		map = em->map_lookup;
666
+		for (i = 0; i < map->num_stripes; i++)
667
+			if (srcdev == map->stripes[i].dev)
668
+				map->stripes[i].dev = tgtdev;
669
+		start = em->start + em->len;
670
+		free_extent_map(em);
671
+	} while (start);
672
+	write_unlock(&em_tree->lock);
584673 }
585674 
586675 static int btrfs_dev_replace_finishing(struct btrfs_fs_info *fs_info,
....@@ -597,50 +686,62 @@
597686 	/* don't allow cancel or unmount to disturb the finishing procedure */
598687 	mutex_lock(&dev_replace->lock_finishing_cancel_unmount);
599688 
600
-	btrfs_dev_replace_read_lock(dev_replace);
689
+	down_read(&dev_replace->rwsem);
601690 	/* was the operation canceled, or is it finished? */
602691 	if (dev_replace->replace_state !=
603692 	    BTRFS_IOCTL_DEV_REPLACE_STATE_STARTED) {
604
-		btrfs_dev_replace_read_unlock(dev_replace);
693
+		up_read(&dev_replace->rwsem);
605694 		mutex_unlock(&dev_replace->lock_finishing_cancel_unmount);
606695 		return 0;
607696 	}
608697 
609698 	tgt_device = dev_replace->tgtdev;
610699 	src_device = dev_replace->srcdev;
611
-	btrfs_dev_replace_read_unlock(dev_replace);
700
+	up_read(&dev_replace->rwsem);
612701 
613702 	/*
614703 	 * flush all outstanding I/O and inode extent mappings before the
615704 	 * copy operation is declared as being finished
616705 	 */
617
-	ret = btrfs_start_delalloc_roots(fs_info, -1);
706
+	ret = btrfs_start_delalloc_roots(fs_info, U64_MAX, false);
618707 	if (ret) {
619708 		mutex_unlock(&dev_replace->lock_finishing_cancel_unmount);
620709 		return ret;
621710 	}
622711 	btrfs_wait_ordered_roots(fs_info, U64_MAX, 0, (u64)-1);
623712 
713
+	if (!scrub_ret)
714
+		btrfs_reada_remove_dev(src_device);
715
+
716
+	/*
717
+	 * We have to use this loop approach because at this point src_device
718
+	 * has to be available for transaction commit to complete, yet new
719
+	 * chunks shouldn't be allocated on the device.
720
+	 */
624721 	while (1) {
625722 		trans = btrfs_start_transaction(root, 0);
626723 		if (IS_ERR(trans)) {
724
+			btrfs_reada_undo_remove_dev(src_device);
627725 			mutex_unlock(&dev_replace->lock_finishing_cancel_unmount);
628726 			return PTR_ERR(trans);
629727 		}
630728 		ret = btrfs_commit_transaction(trans);
631729 		WARN_ON(ret);
632
-		/* keep away write_all_supers() during the finishing procedure */
730
+
731
+		/* Prevent write_all_supers() during the finishing procedure */
633732 		mutex_lock(&fs_info->fs_devices->device_list_mutex);
733
+		/* Prevent new chunks being allocated on the source device */
634734 		mutex_lock(&fs_info->chunk_mutex);
635
-		if (src_device->has_pending_chunks) {
636
-			mutex_unlock(&root->fs_info->chunk_mutex);
637
-			mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
735
+
736
+		if (!list_empty(&src_device->post_commit_list)) {
737
+			mutex_unlock(&fs_info->fs_devices->device_list_mutex);
738
+			mutex_unlock(&fs_info->chunk_mutex);
638739 		} else {
639740 			break;
640741 		}
641742 	}
642743 
643
-	btrfs_dev_replace_write_lock(dev_replace);
744
+	down_write(&dev_replace->rwsem);
644745 	dev_replace->replace_state =
645746 		scrub_ret ? BTRFS_IOCTL_DEV_REPLACE_STATE_CANCELED
646747 			  : BTRFS_IOCTL_DEV_REPLACE_STATE_FINISHED;
....@@ -649,20 +750,29 @@
649750 	dev_replace->time_stopped = ktime_get_real_seconds();
650751 	dev_replace->item_needs_writeback = 1;
651752 
652
-	/* replace old device with new one in mapping tree */
753
+	/*
754
+	 * Update allocation state in the new device and replace the old device
755
+	 * with the new one in the mapping tree.
756
+	 */
653757 	if (!scrub_ret) {
758
+		scrub_ret = btrfs_set_target_alloc_state(src_device, tgt_device);
759
+		if (scrub_ret)
760
+			goto error;
654761 		btrfs_dev_replace_update_device_in_mapping_tree(fs_info,
655762 								src_device,
656763 								tgt_device);
657764 	} else {
658
-		btrfs_err_in_rcu(fs_info,
765
+		if (scrub_ret != -ECANCELED)
766
+			btrfs_err_in_rcu(fs_info,
659767 				 "btrfs_scrub_dev(%s, %llu, %s) failed %d",
660768 				 btrfs_dev_name(src_device),
661769 				 src_device->devid,
662770 				 rcu_str_deref(tgt_device->name), scrub_ret);
663
-		btrfs_dev_replace_write_unlock(dev_replace);
771
+error:
772
+		up_write(&dev_replace->rwsem);
664773 		mutex_unlock(&fs_info->chunk_mutex);
665774 		mutex_unlock(&fs_info->fs_devices->device_list_mutex);
775
+		btrfs_reada_undo_remove_dev(src_device);
666776 		btrfs_rm_dev_replace_blocked(fs_info);
667777 		if (tgt_device)
668778 			btrfs_destroy_dev_replace_tgtdev(tgt_device);
....@@ -687,8 +797,6 @@
687797 	btrfs_device_set_disk_total_bytes(tgt_device,
688798 					  src_device->disk_total_bytes);
689799 	btrfs_device_set_bytes_used(tgt_device, src_device->bytes_used);
690
-	ASSERT(list_empty(&src_device->resized_list));
691
-	tgt_device->commit_total_bytes = src_device->commit_total_bytes;
692800 	tgt_device->commit_bytes_used = src_device->bytes_used;
693801 
694802 	btrfs_assign_next_active_device(src_device, tgt_device);
....@@ -696,8 +804,7 @@
696804 	list_add(&tgt_device->dev_alloc_list, &fs_info->fs_devices->alloc_list);
697805 	fs_info->fs_devices->rw_devices++;
698806 
699
-	btrfs_dev_replace_write_unlock(dev_replace);
700
-
807
+	up_write(&dev_replace->rwsem);
701808 	btrfs_rm_dev_replace_blocked(fs_info);
702809 
703810 	btrfs_rm_dev_replace_remove_srcdev(src_device);
....@@ -721,8 +828,11 @@
721828 	mutex_unlock(&fs_info->fs_devices->device_list_mutex);
722829 
723830 	/* replace the sysfs entry */
724
-	btrfs_sysfs_rm_device_link(fs_info->fs_devices, src_device);
725
-	btrfs_rm_dev_replace_free_srcdev(fs_info, src_device);
831
+	btrfs_sysfs_remove_device(src_device);
832
+	btrfs_sysfs_update_devid(tgt_device);
833
+	if (test_bit(BTRFS_DEV_STATE_WRITEABLE, &src_device->dev_state))
834
+		btrfs_scratch_superblocks(fs_info, src_device->bdev,
835
+					  src_device->name->str);
726836 
727837 	/* write back the superblocks */
728838 	trans = btrfs_start_transaction(root, 0);
....@@ -731,33 +841,9 @@
731841 
732842 	mutex_unlock(&dev_replace->lock_finishing_cancel_unmount);
733843 
844
+	btrfs_rm_dev_replace_free_srcdev(src_device);
845
+
734846 	return 0;
735
-}
736
-
737
-static void btrfs_dev_replace_update_device_in_mapping_tree(
738
-						struct btrfs_fs_info *fs_info,
739
-						struct btrfs_device *srcdev,
740
-						struct btrfs_device *tgtdev)
741
-{
742
-	struct extent_map_tree *em_tree = &fs_info->mapping_tree.map_tree;
743
-	struct extent_map *em;
744
-	struct map_lookup *map;
745
-	u64 start = 0;
746
-	int i;
747
-
748
-	write_lock(&em_tree->lock);
749
-	do {
750
-		em = lookup_extent_mapping(em_tree, start, (u64)-1);
751
-		if (!em)
752
-			break;
753
-		map = em->map_lookup;
754
-		for (i = 0; i < map->num_stripes; i++)
755
-			if (srcdev == map->stripes[i].dev)
756
-				map->stripes[i].dev = tgtdev;
757
-		start = em->start + em->len;
758
-		free_extent_map(em);
759
-	} while (start);
760
-	write_unlock(&em_tree->lock);
761847 }
762848 
763849 /*
....@@ -794,7 +880,7 @@
794880 {
795881 	struct btrfs_dev_replace *dev_replace = &fs_info->dev_replace;
796882 
797
-	btrfs_dev_replace_read_lock(dev_replace);
883
+	down_read(&dev_replace->rwsem);
798884 	/* even if !dev_replace_is_valid, the values are good enough for
799885 	 * the replace_status ioctl */
800886 	args->result = BTRFS_IOCTL_DEV_REPLACE_RESULT_NO_ERROR;
....@@ -806,7 +892,7 @@
806892 	args->status.num_uncorrectable_read_errors =
807893 		atomic64_read(&dev_replace->num_uncorrectable_read_errors);
808894 	args->status.progress_1000 = btrfs_dev_replace_progress(fs_info);
809
-	btrfs_dev_replace_read_unlock(dev_replace);
895
+	up_read(&dev_replace->rwsem);
810896 }
811897 
812898 int btrfs_dev_replace_cancel(struct btrfs_fs_info *fs_info)
....@@ -823,18 +909,18 @@
823909 		return -EROFS;
824910 
825911 	mutex_lock(&dev_replace->lock_finishing_cancel_unmount);
826
-	btrfs_dev_replace_write_lock(dev_replace);
912
+	down_write(&dev_replace->rwsem);
827913 	switch (dev_replace->replace_state) {
828914 	case BTRFS_IOCTL_DEV_REPLACE_STATE_NEVER_STARTED:
829915 	case BTRFS_IOCTL_DEV_REPLACE_STATE_FINISHED:
830916 	case BTRFS_IOCTL_DEV_REPLACE_STATE_CANCELED:
831917 		result = BTRFS_IOCTL_DEV_REPLACE_RESULT_NOT_STARTED;
832
-		btrfs_dev_replace_write_unlock(dev_replace);
918
+		up_write(&dev_replace->rwsem);
833919 		break;
834920 	case BTRFS_IOCTL_DEV_REPLACE_STATE_STARTED:
835921 		tgt_device = dev_replace->tgtdev;
836922 		src_device = dev_replace->srcdev;
837
-		btrfs_dev_replace_write_unlock(dev_replace);
923
+		up_write(&dev_replace->rwsem);
838924 		ret = btrfs_scrub_cancel(fs_info);
839925 		if (ret < 0) {
840926 			result = BTRFS_IOCTL_DEV_REPLACE_RESULT_NOT_STARTED;
....@@ -865,8 +951,9 @@
865951 		dev_replace->time_stopped = ktime_get_real_seconds();
866952 		dev_replace->item_needs_writeback = 1;
867953 
868
-		btrfs_dev_replace_write_unlock(dev_replace);
954
+		up_write(&dev_replace->rwsem);
869955 
956
+		/* Scrub for replace must not be running in suspended state */
870957 		btrfs_scrub_cancel(fs_info);
871958 
872959 		trans = btrfs_start_transaction(root, 0);
....@@ -886,6 +973,7 @@
886973 			btrfs_destroy_dev_replace_tgtdev(tgt_device);
887974 		break;
888975 	default:
976
+		up_write(&dev_replace->rwsem);
889977 		result = -EINVAL;
890978 	}
891979 
....@@ -898,7 +986,8 @@
898986 	struct btrfs_dev_replace *dev_replace = &fs_info->dev_replace;
899987 
900988 	mutex_lock(&dev_replace->lock_finishing_cancel_unmount);
901
-	btrfs_dev_replace_write_lock(dev_replace);
989
+	down_write(&dev_replace->rwsem);
990
+
902991 	switch (dev_replace->replace_state) {
903992 	case BTRFS_IOCTL_DEV_REPLACE_STATE_NEVER_STARTED:
904993 	case BTRFS_IOCTL_DEV_REPLACE_STATE_FINISHED:
....@@ -914,7 +1003,7 @@
9141003 		break;
9151004 	}
9161005 
917
-	btrfs_dev_replace_write_unlock(dev_replace);
1006
+	up_write(&dev_replace->rwsem);
9181007 	mutex_unlock(&dev_replace->lock_finishing_cancel_unmount);
9191008 }
9201009 
....@@ -924,12 +1013,13 @@
9241013 	struct task_struct *task;
9251014 	struct btrfs_dev_replace *dev_replace = &fs_info->dev_replace;
9261015 
927
-	btrfs_dev_replace_write_lock(dev_replace);
1016
+	down_write(&dev_replace->rwsem);
1017
+
9281018 	switch (dev_replace->replace_state) {
9291019 	case BTRFS_IOCTL_DEV_REPLACE_STATE_NEVER_STARTED:
9301020 	case BTRFS_IOCTL_DEV_REPLACE_STATE_FINISHED:
9311021 	case BTRFS_IOCTL_DEV_REPLACE_STATE_CANCELED:
932
-		btrfs_dev_replace_write_unlock(dev_replace);
1022
+		up_write(&dev_replace->rwsem);
9331023 		return 0;
9341024 	case BTRFS_IOCTL_DEV_REPLACE_STATE_STARTED:
9351025 		break;
....@@ -945,21 +1035,21 @@
9451035 			   "you may cancel the operation after 'mount -o degraded'");
9461036 		dev_replace->replace_state =
9471037 					BTRFS_IOCTL_DEV_REPLACE_STATE_SUSPENDED;
948
-		btrfs_dev_replace_write_unlock(dev_replace);
1038
+		up_write(&dev_replace->rwsem);
9491039 		return 0;
9501040 	}
951
-	btrfs_dev_replace_write_unlock(dev_replace);
1041
+	up_write(&dev_replace->rwsem);
9521042 
9531043 	/*
9541044 	 * This could collide with a paused balance, but the exclusive op logic
9551045 	 * should never allow both to start and pause. We don't want to allow
9561046 	 * dev-replace to start anyway.
9571047 	 */
958
-	if (test_and_set_bit(BTRFS_FS_EXCL_OP, &fs_info->flags)) {
959
-		btrfs_dev_replace_write_lock(dev_replace);
1048
+	if (!btrfs_exclop_start(fs_info, BTRFS_EXCLOP_DEV_REPLACE)) {
1049
+		down_write(&dev_replace->rwsem);
9601050 		dev_replace->replace_state =
9611051 					BTRFS_IOCTL_DEV_REPLACE_STATE_SUSPENDED;
962
-		btrfs_dev_replace_write_unlock(dev_replace);
1052
+		up_write(&dev_replace->rwsem);
9631053 		btrfs_info(fs_info,
9641054 		"cannot resume dev-replace, other exclusive operation running");
9651055 		return 0;
....@@ -990,13 +1080,13 @@
9901080 			      btrfs_device_get_total_bytes(dev_replace->srcdev),
9911081 			      &dev_replace->scrub_progress, 0, 1);
9921082 	ret = btrfs_dev_replace_finishing(fs_info, ret);
993
-	WARN_ON(ret);
1083
+	WARN_ON(ret && ret != -ECANCELED);
9941084 
995
-	clear_bit(BTRFS_FS_EXCL_OP, &fs_info->flags);
1085
+	btrfs_exclop_finish(fs_info);
9961086 	return 0;
9971087 }
9981088 
999
-int btrfs_dev_replace_is_ongoing(struct btrfs_dev_replace *dev_replace)
1089
+int __pure btrfs_dev_replace_is_ongoing(struct btrfs_dev_replace *dev_replace)
10001090 {
10011091 	if (!dev_replace->is_valid)
10021092 		return 0;
....@@ -1013,7 +1103,7 @@
10131103 		 * something that can happen if the dev_replace
10141104 		 * procedure is suspended by an umount and then
10151105 		 * the tgtdev is missing (or "btrfs dev scan") was
1016
-		 * not called and the the filesystem is remounted
1106
+		 * not called and the filesystem is remounted
10171107 		 * in degraded state. This does not stop the
10181108 		 * dev_replace procedure. It needs to be canceled
10191109 		 * manually if the cancellation is wanted.
....@@ -1023,81 +1113,27 @@
10231113 	return 1;
10241114 }
10251115 
1026
-void btrfs_dev_replace_read_lock(struct btrfs_dev_replace *dev_replace)
1027
-{
1028
-	read_lock(&dev_replace->lock);
1029
-	atomic_inc(&dev_replace->read_locks);
1030
-}
1031
-
1032
-void btrfs_dev_replace_read_unlock(struct btrfs_dev_replace *dev_replace)
1033
-{
1034
-	ASSERT(atomic_read(&dev_replace->read_locks) > 0);
1035
-	atomic_dec(&dev_replace->read_locks);
1036
-	read_unlock(&dev_replace->lock);
1037
-}
1038
-
1039
-void btrfs_dev_replace_write_lock(struct btrfs_dev_replace *dev_replace)
1040
-{
1041
-again:
1042
-	wait_event(dev_replace->read_lock_wq,
1043
-		   atomic_read(&dev_replace->blocking_readers) == 0);
1044
-	write_lock(&dev_replace->lock);
1045
-	if (atomic_read(&dev_replace->blocking_readers)) {
1046
-		write_unlock(&dev_replace->lock);
1047
-		goto again;
1048
-	}
1049
-}
1050
-
1051
-void btrfs_dev_replace_write_unlock(struct btrfs_dev_replace *dev_replace)
1052
-{
1053
-	ASSERT(atomic_read(&dev_replace->blocking_readers) == 0);
1054
-	write_unlock(&dev_replace->lock);
1055
-}
1056
-
1057
-/* inc blocking cnt and release read lock */
1058
-void btrfs_dev_replace_set_lock_blocking(
1059
-					struct btrfs_dev_replace *dev_replace)
1060
-{
1061
-	/* only set blocking for read lock */
1062
-	ASSERT(atomic_read(&dev_replace->read_locks) > 0);
1063
-	atomic_inc(&dev_replace->blocking_readers);
1064
-	read_unlock(&dev_replace->lock);
1065
-}
1066
-
1067
-/* acquire read lock and dec blocking cnt */
1068
-void btrfs_dev_replace_clear_lock_blocking(
1069
-					struct btrfs_dev_replace *dev_replace)
1070
-{
1071
-	/* only set blocking for read lock */
1072
-	ASSERT(atomic_read(&dev_replace->read_locks) > 0);
1073
-	ASSERT(atomic_read(&dev_replace->blocking_readers) > 0);
1074
-	read_lock(&dev_replace->lock);
1075
-	/* Barrier implied by atomic_dec_and_test */
1076
-	if (atomic_dec_and_test(&dev_replace->blocking_readers))
1077
-		cond_wake_up_nomb(&dev_replace->read_lock_wq);
1078
-}
1079
-
10801116 void btrfs_bio_counter_inc_noblocked(struct btrfs_fs_info *fs_info)
10811117 {
1082
-	percpu_counter_inc(&fs_info->bio_counter);
1118
+	percpu_counter_inc(&fs_info->dev_replace.bio_counter);
10831119 }
10841120 
10851121 void btrfs_bio_counter_sub(struct btrfs_fs_info *fs_info, s64 amount)
10861122 {
1087
-	percpu_counter_sub(&fs_info->bio_counter, amount);
1088
-	cond_wake_up_nomb(&fs_info->replace_wait);
1123
+	percpu_counter_sub(&fs_info->dev_replace.bio_counter, amount);
1124
+	cond_wake_up_nomb(&fs_info->dev_replace.replace_wait);
10891125 }
10901126 
10911127 void btrfs_bio_counter_inc_blocked(struct btrfs_fs_info *fs_info)
10921128 {
10931129 	while (1) {
1094
-		percpu_counter_inc(&fs_info->bio_counter);
1130
+		percpu_counter_inc(&fs_info->dev_replace.bio_counter);
10951131 		if (likely(!test_bit(BTRFS_FS_STATE_DEV_REPLACING,
10961132 				     &fs_info->fs_state)))
10971133 			break;
10981134 
10991135 		btrfs_bio_counter_dec(fs_info);
1100
-		wait_event(fs_info->replace_wait,
1136
+		wait_event(fs_info->dev_replace.replace_wait,
11011137 			   !test_bit(BTRFS_FS_STATE_DEV_REPLACING,
11021138 				     &fs_info->fs_state));
11031139 	}