1 files changed, 156 insertions, 176 deletions

diff --git a/fs/btrfs/dev-replace.c b/fs/btrfs/dev-replace.c
index 62b9651ea662..b6c7da8e1bc8 100644
--- a/fs/btrfs/dev-replace.c
+++ b/fs/btrfs/dev-replace.c
@@ -11,18 +11,17 @@
 #include <linux/math64.h>
 #include "misc.h"
 #include "ctree.h"
-#include "extent_map.h"
 #include "disk-io.h"
 #include "transaction.h"
-#include "print-tree.h"
 #include "volumes.h"
 #include "async-thread.h"
-#include "check-integrity.h"
-#include "rcu-string.h"
 #include "dev-replace.h"
 #include "sysfs.h"
 #include "zoned.h"
 #include "block-group.h"
+#include "fs.h"
+#include "accessors.h"
+#include "scrub.h"
 
 /*
  * Device replace overview
@@ -39,14 +38,14 @@
  *   All new writes will be written to both target and source devices, so even
  *   if replace gets canceled, sources device still contains up-to-date data.
  *
- *   Location:		handle_ops_on_dev_replace() from __btrfs_map_block()
+ *   Location:		handle_ops_on_dev_replace() from btrfs_map_block()
  *   Start:		btrfs_dev_replace_start()
  *   End:		btrfs_dev_replace_finishing()
  *   Content:		Latest data/metadata
  *
  * - Copy existing extents
  *
- *   This happens by re-using scrub facility, as scrub also iterates through
+ *   This happens by reusing scrub facility, as scrub also iterates through
  *   existing extents from commit root.
  *
  *   Location:		scrub_write_block_to_dev_replace() from
@@ -77,7 +76,7 @@ int btrfs_init_dev_replace(struct btrfs_fs_info *fs_info)
 	struct extent_buffer *eb;
 	int slot;
 	int ret = 0;
-	struct btrfs_path *path = NULL;
+	BTRFS_PATH_AUTO_FREE(path);
 	int item_size;
 	struct btrfs_dev_replace_item *ptr;
 	u64 src_devid;
@@ -86,10 +85,8 @@ int btrfs_init_dev_replace(struct btrfs_fs_info *fs_info)
 		return 0;
 
 	path = btrfs_alloc_path();
-	if (!path) {
-		ret = -ENOMEM;
-		goto out;
-	}
+	if (!path)
+		return -ENOMEM;
 
 	key.objectid = 0;
 	key.type = BTRFS_DEV_REPLACE_KEY;
@@ -101,13 +98,11 @@ no_valid_dev_replace_entry_found:
 		 * We don't have a replace item or it's corrupted.  If there is
 		 * a replace target, fail the mount.
 		 */
-		if (btrfs_find_device(fs_info->fs_devices, &args)) {
+		if (unlikely(btrfs_find_device(fs_info->fs_devices, &args))) {
 			btrfs_err(fs_info,
 			"found replace target device without a valid replace item");
-			ret = -EUCLEAN;
-			goto out;
+			return -EUCLEAN;
 		}
-		ret = 0;
 		dev_replace->replace_state =
 			BTRFS_IOCTL_DEV_REPLACE_STATE_NEVER_STARTED;
 		dev_replace->cont_reading_from_srcdev_mode =
@@ -124,7 +119,7 @@ no_valid_dev_replace_entry_found:
 		dev_replace->tgtdev = NULL;
 		dev_replace->is_valid = 0;
 		dev_replace->item_needs_writeback = 0;
-		goto out;
+		return 0;
 	}
 	slot = path->slots[0];
 	eb = path->nodes[0];
@@ -163,9 +158,9 @@ no_valid_dev_replace_entry_found:
 		 * We don't have an active replace item but if there is a
 		 * replace target, fail the mount.
 		 */
-		if (btrfs_find_device(fs_info->fs_devices, &args)) {
+		if (unlikely(btrfs_find_device(fs_info->fs_devices, &args))) {
 			btrfs_err(fs_info,
-			"replace devid present without an active replace item");
+"replace without active item, run 'device scan --forget' on the target device");
 			ret = -EUCLEAN;
 		} else {
 			dev_replace->srcdev = NULL;
@@ -182,8 +177,7 @@ no_valid_dev_replace_entry_found:
 		 * allow 'btrfs dev replace_cancel' if src/tgt device is
 		 * missing
 		 */
-		if (!dev_replace->srcdev &&
-		    !btrfs_test_opt(fs_info, DEGRADED)) {
+		if (unlikely(!dev_replace->srcdev && !btrfs_test_opt(fs_info, DEGRADED))) {
 			ret = -EIO;
 			btrfs_warn(fs_info,
 			   "cannot mount because device replace operation is ongoing and");
@@ -191,8 +185,7 @@ no_valid_dev_replace_entry_found:
 			   "srcdev (devid %llu) is missing, need to run 'btrfs dev scan'?",
 			   src_devid);
 		}
-		if (!dev_replace->tgtdev &&
-		    !btrfs_test_opt(fs_info, DEGRADED)) {
+		if (unlikely(!dev_replace->tgtdev && !btrfs_test_opt(fs_info, DEGRADED))) {
 			ret = -EIO;
 			btrfs_warn(fs_info,
 			   "cannot mount because device replace operation is ongoing and");
@@ -227,8 +220,6 @@ no_valid_dev_replace_entry_found:
 		break;
 	}
 
-out:
-	btrfs_free_path(path);
 	return ret;
 }
 
@@ -243,9 +234,10 @@ static int btrfs_init_dev_replace_tgtdev(struct btrfs_fs_info *fs_info,
 				  struct btrfs_device *srcdev,
 				  struct btrfs_device **device_out)
 {
+	struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
 	struct btrfs_device *device;
+	struct file *bdev_file;
 	struct block_device *bdev;
-	struct rcu_string *name;
 	u64 devid = BTRFS_DEV_REPLACE_DEVID;
 	int ret = 0;
 
@@ -255,12 +247,13 @@ static int btrfs_init_dev_replace_tgtdev(struct btrfs_fs_info *fs_info,
 		return -EINVAL;
 	}
 
-	bdev = blkdev_get_by_path(device_path, FMODE_WRITE | FMODE_EXCL,
-				  fs_info->bdev_holder);
-	if (IS_ERR(bdev)) {
+	bdev_file = bdev_file_open_by_path(device_path, BLK_OPEN_WRITE,
+					   fs_info->sb, &fs_holder_ops);
+	if (IS_ERR(bdev_file)) {
 		btrfs_err(fs_info, "target device %s is invalid!", device_path);
-		return PTR_ERR(bdev);
+		return PTR_ERR(bdev_file);
 	}
+	bdev = file_bdev(bdev_file);
 
 	if (!btrfs_check_device_zone_type(fs_info, bdev)) {
 		btrfs_err(fs_info,
@@ -271,7 +264,7 @@ static int btrfs_init_dev_replace_tgtdev(struct btrfs_fs_info *fs_info,
 
 	sync_blockdev(bdev);
 
-	list_for_each_entry(device, &fs_info->fs_devices->devices, dev_list) {
+	list_for_each_entry(device, &fs_devices->devices, dev_list) {
 		if (device->bdev == bdev) {
 			btrfs_err(fs_info,
 				  "target device is in the filesystem!");
@@ -289,19 +282,15 @@ static int btrfs_init_dev_replace_tgtdev(struct btrfs_fs_info *fs_info,
 	}
 
 
-	device = btrfs_alloc_device(NULL, &devid, NULL);
+	device = btrfs_alloc_device(NULL, &devid, NULL, device_path);
 	if (IS_ERR(device)) {
 		ret = PTR_ERR(device);
 		goto error;
 	}
 
-	name = rcu_string_strdup(device_path, GFP_KERNEL);
-	if (!name) {
-		btrfs_free_device(device);
-		ret = -ENOMEM;
+	ret = lookup_bdev(device_path, &device->devt);
+	if (ret)
 		goto error;
-	}
-	rcu_assign_pointer(device->name, name);
 
 	set_bit(BTRFS_DEV_STATE_WRITEABLE, &device->dev_state);
 	device->generation = 0;
@@ -315,28 +304,28 @@ static int btrfs_init_dev_replace_tgtdev(struct btrfs_fs_info *fs_info,
 	device->commit_bytes_used = device->bytes_used;
 	device->fs_info = fs_info;
 	device->bdev = bdev;
+	device->bdev_file = bdev_file;
 	set_bit(BTRFS_DEV_STATE_IN_FS_METADATA, &device->dev_state);
 	set_bit(BTRFS_DEV_STATE_REPLACE_TGT, &device->dev_state);
-	device->mode = FMODE_EXCL;
 	device->dev_stats_valid = 1;
-	set_blocksize(device->bdev, BTRFS_BDEV_BLOCKSIZE);
-	device->fs_devices = fs_info->fs_devices;
+	set_blocksize(bdev_file, BTRFS_BDEV_BLOCKSIZE);
+	device->fs_devices = fs_devices;
 
 	ret = btrfs_get_dev_zone_info(device, false);
 	if (ret)
 		goto error;
 
-	mutex_lock(&fs_info->fs_devices->device_list_mutex);
-	list_add(&device->dev_list, &fs_info->fs_devices->devices);
-	fs_info->fs_devices->num_devices++;
-	fs_info->fs_devices->open_devices++;
-	mutex_unlock(&fs_info->fs_devices->device_list_mutex);
+	mutex_lock(&fs_devices->device_list_mutex);
+	list_add(&device->dev_list, &fs_devices->devices);
+	fs_devices->num_devices++;
+	fs_devices->open_devices++;
+	mutex_unlock(&fs_devices->device_list_mutex);
 
 	*device_out = device;
 	return 0;
 
 error:
-	blkdev_put(bdev, FMODE_EXCL);
+	bdev_fput(bdev_file);
 	return ret;
 }
 
@@ -349,7 +338,7 @@ int btrfs_run_dev_replace(struct btrfs_trans_handle *trans)
 	struct btrfs_fs_info *fs_info = trans->fs_info;
 	int ret;
 	struct btrfs_root *dev_root = fs_info->dev_root;
-	struct btrfs_path *path;
+	BTRFS_PATH_AUTO_FREE(path);
 	struct btrfs_key key;
 	struct extent_buffer *eb;
 	struct btrfs_dev_replace_item *ptr;
@@ -368,16 +357,15 @@ int btrfs_run_dev_replace(struct btrfs_trans_handle *trans)
 	key.offset = 0;
 
 	path = btrfs_alloc_path();
-	if (!path) {
-		ret = -ENOMEM;
-		goto out;
-	}
+	if (!path)
+		return -ENOMEM;
+
 	ret = btrfs_search_slot(trans, dev_root, &key, path, -1, 1);
 	if (ret < 0) {
 		btrfs_warn(fs_info,
 			   "error %d while searching for dev_replace item!",
 			   ret);
-		goto out;
+		return ret;
 	}
 
 	if (ret == 0 &&
@@ -398,7 +386,7 @@ int btrfs_run_dev_replace(struct btrfs_trans_handle *trans)
 			btrfs_warn(fs_info,
 				   "delete too small dev_replace item failed %d!",
 				   ret);
-			goto out;
+			return ret;
 		}
 		ret = 1;
 	}
@@ -411,7 +399,7 @@ int btrfs_run_dev_replace(struct btrfs_trans_handle *trans)
 		if (ret < 0) {
 			btrfs_warn(fs_info,
 				   "insert dev_replace item failed %d!", ret);
-			goto out;
+			return ret;
 		}
 	}
 
@@ -444,22 +432,9 @@ int btrfs_run_dev_replace(struct btrfs_trans_handle *trans)
 	dev_replace->item_needs_writeback = 0;
 	up_write(&dev_replace->rwsem);
 
-	btrfs_mark_buffer_dirty(eb);
-
-out:
-	btrfs_free_path(path);
-
 	return ret;
 }
 
-static char* btrfs_dev_name(struct btrfs_device *device)
-{
-	if (!device || test_bit(BTRFS_DEV_STATE_MISSING, &device->dev_state))
-		return "<missing disk>";
-	else
-		return rcu_str_deref(device->name);
-}
-
 static int mark_block_group_to_copy(struct btrfs_fs_info *fs_info,
 				    struct btrfs_device *src_dev)
 {
@@ -470,6 +445,7 @@ static int mark_block_group_to_copy(struct btrfs_fs_info *fs_info,
 	struct btrfs_dev_extent *dev_extent = NULL;
 	struct btrfs_block_group *cache;
 	struct btrfs_trans_handle *trans;
+	int iter_ret = 0;
 	int ret = 0;
 	u64 chunk_offset;
 
@@ -513,36 +489,15 @@ static int mark_block_group_to_copy(struct btrfs_fs_info *fs_info,
 	}
 
 	path->reada = READA_FORWARD;
-	path->search_commit_root = 1;
-	path->skip_locking = 1;
+	path->search_commit_root = true;
+	path->skip_locking = true;
 
 	key.objectid = src_dev->devid;
 	key.type = BTRFS_DEV_EXTENT_KEY;
 	key.offset = 0;
 
-	ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
-	if (ret < 0)
-		goto free_path;
-	if (ret > 0) {
-		if (path->slots[0] >=
-		    btrfs_header_nritems(path->nodes[0])) {
-			ret = btrfs_next_leaf(root, path);
-			if (ret < 0)
-				goto free_path;
-			if (ret > 0) {
-				ret = 0;
-				goto free_path;
-			}
-		} else {
-			ret = 0;
-		}
-	}
-
-	while (1) {
+	btrfs_for_each_slot(root, &key, &found_key, path, iter_ret) {
 		struct extent_buffer *leaf = path->nodes[0];
-		int slot = path->slots[0];
-
-		btrfs_item_key_to_cpu(leaf, &found_key, slot);
 
 		if (found_key.objectid != src_dev->devid)
 			break;
@@ -553,30 +508,20 @@ static int mark_block_group_to_copy(struct btrfs_fs_info *fs_info,
 		if (found_key.offset < key.offset)
 			break;
 
-		dev_extent = btrfs_item_ptr(leaf, slot, struct btrfs_dev_extent);
+		dev_extent = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_dev_extent);
 
 		chunk_offset = btrfs_dev_extent_chunk_offset(leaf, dev_extent);
 
 		cache = btrfs_lookup_block_group(fs_info, chunk_offset);
 		if (!cache)
-			goto skip;
-
-		spin_lock(&cache->lock);
-		cache->to_copy = 1;
-		spin_unlock(&cache->lock);
+			continue;
 
+		set_bit(BLOCK_GROUP_FLAG_TO_COPY, &cache->runtime_flags);
 		btrfs_put_block_group(cache);
-
-skip:
-		ret = btrfs_next_item(root, path);
-		if (ret != 0) {
-			if (ret > 0)
-				ret = 0;
-			break;
-		}
 	}
+	if (iter_ret < 0)
+		ret = iter_ret;
 
-free_path:
 	btrfs_free_path(path);
 unlock:
 	mutex_unlock(&fs_info->chunk_mutex);
@@ -589,8 +534,7 @@ bool btrfs_finish_block_group_to_copy(struct btrfs_device *srcdev,
 				      u64 physical)
 {
 	struct btrfs_fs_info *fs_info = cache->fs_info;
-	struct extent_map *em;
-	struct map_lookup *map;
+	struct btrfs_chunk_map *map;
 	u64 chunk_offset = cache->start;
 	int num_extents, cur_extent;
 	int i;
@@ -600,17 +544,17 @@ bool btrfs_finish_block_group_to_copy(struct btrfs_device *srcdev,
 		return true;
 
 	spin_lock(&cache->lock);
-	if (cache->removed) {
+	if (test_bit(BLOCK_GROUP_FLAG_REMOVED, &cache->runtime_flags)) {
 		spin_unlock(&cache->lock);
 		return true;
 	}
 	spin_unlock(&cache->lock);
 
-	em = btrfs_get_chunk_map(fs_info, chunk_offset, 1);
-	ASSERT(!IS_ERR(em));
-	map = em->map_lookup;
+	map = btrfs_get_chunk_map(fs_info, chunk_offset, 1);
+	ASSERT(!IS_ERR(map));
 
-	num_extents = cur_extent = 0;
+	num_extents = 0;
+	cur_extent = 0;
 	for (i = 0; i < map->num_stripes; i++) {
 		/* We have more device extent to copy */
 		if (srcdev != map->stripes[i].dev)
@@ -621,7 +565,7 @@ bool btrfs_finish_block_group_to_copy(struct btrfs_device *srcdev,
 			cur_extent = i;
 	}
 
-	free_extent_map(em);
+	btrfs_free_chunk_map(map);
 
 	if (num_extents > 1 && cur_extent < num_extents - 1) {
 		/*
@@ -632,9 +576,7 @@ bool btrfs_finish_block_group_to_copy(struct btrfs_device *srcdev,
 	}
 
 	/* Last stripe on this device */
-	spin_lock(&cache->lock);
-	cache->to_copy = 0;
-	spin_unlock(&cache->lock);
+	clear_bit(BLOCK_GROUP_FLAG_TO_COPY, &cache->runtime_flags);
 
 	return true;
 }
@@ -656,7 +598,7 @@ static int btrfs_dev_replace_start(struct btrfs_fs_info *fs_info,
 		return PTR_ERR(src_device);
 
 	if (btrfs_pinned_by_swapfile(fs_info, src_device)) {
-		btrfs_warn_in_rcu(fs_info,
+		btrfs_warn(fs_info,
 	  "cannot replace device %s (devid %llu) due to active swapfile",
 			btrfs_dev_name(src_device), src_device->devid);
 		return -ETXTBSY;
@@ -685,6 +627,7 @@ static int btrfs_dev_replace_start(struct btrfs_fs_info *fs_info,
 		return ret;
 
 	down_write(&dev_replace->rwsem);
+	dev_replace->replace_task = current;
 	switch (dev_replace->replace_state) {
 	case BTRFS_IOCTL_DEV_REPLACE_STATE_NEVER_STARTED:
 	case BTRFS_IOCTL_DEV_REPLACE_STATE_FINISHED:
@@ -692,7 +635,7 @@ static int btrfs_dev_replace_start(struct btrfs_fs_info *fs_info,
 		break;
 	case BTRFS_IOCTL_DEV_REPLACE_STATE_STARTED:
 	case BTRFS_IOCTL_DEV_REPLACE_STATE_SUSPENDED:
-		ASSERT(0);
+		DEBUG_WARN("unexpected STARTED or SUSPENDED dev-replace state");
 		ret = BTRFS_IOCTL_DEV_REPLACE_RESULT_ALREADY_STARTED;
 		up_write(&dev_replace->rwsem);
 		goto leave;
@@ -702,11 +645,11 @@ static int btrfs_dev_replace_start(struct btrfs_fs_info *fs_info,
 	dev_replace->srcdev = src_device;
 	dev_replace->tgtdev = tgt_device;
 
-	btrfs_info_in_rcu(fs_info,
+	btrfs_info(fs_info,
 		      "dev_replace from %s (devid %llu) to %s started",
 		      btrfs_dev_name(src_device),
 		      src_device->devid,
-		      rcu_str_deref(tgt_device->name));
+		      btrfs_dev_name(tgt_device));
 
 	/*
 	 * from now on, the writes to the srcdev are all duplicated to
@@ -728,9 +671,14 @@ static int btrfs_dev_replace_start(struct btrfs_fs_info *fs_info,
 	if (ret)
 		btrfs_err(fs_info, "kobj add dev failed %d", ret);
 
-	btrfs_wait_ordered_roots(fs_info, U64_MAX, 0, (u64)-1);
+	btrfs_wait_ordered_roots(fs_info, U64_MAX, NULL);
 
-	/* Commit dev_replace state and reserve 1 item for it. */
+	/*
+	 * Commit dev_replace state and reserve 1 item for it.
+	 * This is crucial to ensure we won't miss copying extents for new block
+	 * groups that are allocated after we started the device replace, and
+	 * must be done after setting up the device replace state.
+	 */
 	trans = btrfs_start_transaction(root, 1);
 	if (IS_ERR(trans)) {
 		ret = PTR_ERR(trans);
@@ -762,6 +710,23 @@ leave:
 	return ret;
 }
 
+static int btrfs_check_replace_dev_names(struct btrfs_ioctl_dev_replace_args *args)
+{
+	if (args->start.srcdevid == 0) {
+		if (memchr(args->start.srcdev_name, 0,
+			   sizeof(args->start.srcdev_name)) == NULL)
+			return -ENAMETOOLONG;
+	} else {
+		args->start.srcdev_name[0] = 0;
+	}
+
+	if (memchr(args->start.tgtdev_name, 0,
+		   sizeof(args->start.tgtdev_name)) == NULL)
+	    return -ENAMETOOLONG;
+
+	return 0;
+}
+
 int btrfs_dev_replace_by_ioctl(struct btrfs_fs_info *fs_info,
 			    struct btrfs_ioctl_dev_replace_args *args)
 {
@@ -774,10 +739,9 @@ int btrfs_dev_replace_by_ioctl(struct btrfs_fs_info *fs_info,
 	default:
 		return -EINVAL;
 	}
-
-	if ((args->start.srcdevid == 0 && args->start.srcdev_name[0] == '\0') ||
-	    args->start.tgtdev_name[0] == '\0')
-		return -EINVAL;
+	ret = btrfs_check_replace_dev_names(args);
+	if (ret < 0)
+		return ret;
 
 	ret = btrfs_dev_replace_start(fs_info, args->start.tgtdev_name,
 					args->start.srcdevid,
@@ -828,17 +792,17 @@ static int btrfs_set_target_alloc_state(struct btrfs_device *srcdev,
 
 	lockdep_assert_held(&srcdev->fs_info->chunk_mutex);
 
-	while (!find_first_extent_bit(&srcdev->alloc_state, start,
-				      &found_start, &found_end,
-				      CHUNK_ALLOCATED, &cached_state)) {
-		ret = set_extent_bits(&tgtdev->alloc_state, found_start,
-				      found_end, CHUNK_ALLOCATED);
+	while (btrfs_find_first_extent_bit(&srcdev->alloc_state, start,
+					   &found_start, &found_end,
+					   CHUNK_ALLOCATED, &cached_state)) {
+		ret = btrfs_set_extent_bit(&tgtdev->alloc_state, found_start,
+					   found_end, CHUNK_ALLOCATED, NULL);
 		if (ret)
 			break;
 		start = found_end + 1;
 	}
 
-	free_extent_state(cached_state);
+	btrfs_free_extent_state(cached_state);
 	return ret;
 }
 
@@ -847,31 +811,53 @@ static void btrfs_dev_replace_update_device_in_mapping_tree(
 						struct btrfs_device *srcdev,
 						struct btrfs_device *tgtdev)
 {
-	struct extent_map_tree *em_tree = &fs_info->mapping_tree;
-	struct extent_map *em;
-	struct map_lookup *map;
-	u64 start = 0;
-	int i;
+	struct rb_node *node;
 
-	write_lock(&em_tree->lock);
-	do {
-		em = lookup_extent_mapping(em_tree, start, (u64)-1);
-		if (!em)
-			break;
-		map = em->map_lookup;
-		for (i = 0; i < map->num_stripes; i++)
+	/*
+	 * The chunk mutex must be held so that no new chunks can be created
+	 * while we are updating existing chunks. This guarantees we don't miss
+	 * any new chunk that gets created for a range that falls before the
+	 * range of the last chunk we processed.
+	 */
+	lockdep_assert_held(&fs_info->chunk_mutex);
+
+	write_lock(&fs_info->mapping_tree_lock);
+	node = rb_first_cached(&fs_info->mapping_tree);
+	while (node) {
+		struct rb_node *next = rb_next(node);
+		struct btrfs_chunk_map *map;
+		u64 next_start;
+
+		map = rb_entry(node, struct btrfs_chunk_map, rb_node);
+		next_start = map->start + map->chunk_len;
+
+		for (int i = 0; i < map->num_stripes; i++)
 			if (srcdev == map->stripes[i].dev)
 				map->stripes[i].dev = tgtdev;
-		start = em->start + em->len;
-		free_extent_map(em);
-	} while (start);
-	write_unlock(&em_tree->lock);
+
+		if (cond_resched_rwlock_write(&fs_info->mapping_tree_lock)) {
+			map = btrfs_find_chunk_map_nolock(fs_info, next_start, U64_MAX);
+			if (!map)
+				break;
+			node = &map->rb_node;
+			/*
+			 * Drop the lookup reference since we are holding the
+			 * lock in write mode and no one can remove the chunk
+			 * map from the tree and drop its tree reference.
+			 */
+			btrfs_free_chunk_map(map);
+		} else {
+			node = next;
+		}
+	}
+	write_unlock(&fs_info->mapping_tree_lock);
 }
 
 static int btrfs_dev_replace_finishing(struct btrfs_fs_info *fs_info,
 				       int scrub_ret)
 {
 	struct btrfs_dev_replace *dev_replace = &fs_info->dev_replace;
+	struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
 	struct btrfs_device *tgt_device;
 	struct btrfs_device *src_device;
 	struct btrfs_root *root = fs_info->tree_root;
@@ -904,7 +890,7 @@ static int btrfs_dev_replace_finishing(struct btrfs_fs_info *fs_info,
 		mutex_unlock(&dev_replace->lock_finishing_cancel_unmount);
 		return ret;
 	}
-	btrfs_wait_ordered_roots(fs_info, U64_MAX, 0, (u64)-1);
+	btrfs_wait_ordered_roots(fs_info, U64_MAX, NULL);
 
 	/*
 	 * We have to use this loop approach because at this point src_device
@@ -921,12 +907,12 @@ static int btrfs_dev_replace_finishing(struct btrfs_fs_info *fs_info,
 		WARN_ON(ret);
 
 		/* Prevent write_all_supers() during the finishing procedure */
-		mutex_lock(&fs_info->fs_devices->device_list_mutex);
+		mutex_lock(&fs_devices->device_list_mutex);
 		/* Prevent new chunks being allocated on the source device */
 		mutex_lock(&fs_info->chunk_mutex);
 
 		if (!list_empty(&src_device->post_commit_list)) {
-			mutex_unlock(&fs_info->fs_devices->device_list_mutex);
+			mutex_unlock(&fs_devices->device_list_mutex);
 			mutex_unlock(&fs_info->chunk_mutex);
 		} else {
 			break;
@@ -955,15 +941,15 @@ static int btrfs_dev_replace_finishing(struct btrfs_fs_info *fs_info,
 								tgt_device);
 	} else {
 		if (scrub_ret != -ECANCELED)
-			btrfs_err_in_rcu(fs_info,
+			btrfs_err(fs_info,
 				 "btrfs_scrub_dev(%s, %llu, %s) failed %d",
 				 btrfs_dev_name(src_device),
 				 src_device->devid,
-				 rcu_str_deref(tgt_device->name), scrub_ret);
+				 btrfs_dev_name(tgt_device), scrub_ret);
 error:
 		up_write(&dev_replace->rwsem);
 		mutex_unlock(&fs_info->chunk_mutex);
-		mutex_unlock(&fs_info->fs_devices->device_list_mutex);
+		mutex_unlock(&fs_devices->device_list_mutex);
 		btrfs_rm_dev_replace_blocked(fs_info);
 		if (tgt_device)
 			btrfs_destroy_dev_replace_tgtdev(tgt_device);
@@ -973,11 +959,11 @@ error:
 		return scrub_ret;
 	}
 
-	btrfs_info_in_rcu(fs_info,
+	btrfs_info(fs_info,
 			  "dev_replace from %s (devid %llu) to %s finished",
 			  btrfs_dev_name(src_device),
 			  src_device->devid,
-			  rcu_str_deref(tgt_device->name));
+			  btrfs_dev_name(tgt_device));
 	clear_bit(BTRFS_DEV_STATE_REPLACE_TGT, &tgt_device->dev_state);
 	tgt_device->devid = src_device->devid;
 	src_device->devid = BTRFS_DEV_REPLACE_DEVID;
@@ -992,9 +978,10 @@ error:
 
 	btrfs_assign_next_active_device(src_device, tgt_device);
 
-	list_add(&tgt_device->dev_alloc_list, &fs_info->fs_devices->alloc_list);
-	fs_info->fs_devices->rw_devices++;
+	list_add(&tgt_device->dev_alloc_list, &fs_devices->alloc_list);
+	fs_devices->rw_devices++;
 
+	dev_replace->replace_task = NULL;
 	up_write(&dev_replace->rwsem);
 	btrfs_rm_dev_replace_blocked(fs_info);
 
@@ -1016,14 +1003,13 @@ error:
 	 * belong to this filesystem.
 	 */
 	mutex_unlock(&fs_info->chunk_mutex);
-	mutex_unlock(&fs_info->fs_devices->device_list_mutex);
+	mutex_unlock(&fs_devices->device_list_mutex);
 
 	/* replace the sysfs entry */
 	btrfs_sysfs_remove_device(src_device);
 	btrfs_sysfs_update_devid(tgt_device);
 	if (test_bit(BTRFS_DEV_STATE_WRITEABLE, &src_device->dev_state))
-		btrfs_scratch_superblocks(fs_info, src_device->bdev,
-					  src_device->name->str);
+		btrfs_scratch_superblocks(fs_info, src_device);
 
 	/* write back the superblocks */
 	trans = btrfs_start_transaction(root, 0);
@@ -1121,7 +1107,7 @@ int btrfs_dev_replace_cancel(struct btrfs_fs_info *fs_info)
 			 * btrfs_dev_replace_finishing() will handle the
 			 * cleanup part
 			 */
-			btrfs_info_in_rcu(fs_info,
+			btrfs_info(fs_info,
 				"dev_replace from %s (devid %llu) to %s canceled",
 				btrfs_dev_name(src_device), src_device->devid,
 				btrfs_dev_name(tgt_device));
@@ -1145,8 +1131,7 @@ int btrfs_dev_replace_cancel(struct btrfs_fs_info *fs_info)
 		up_write(&dev_replace->rwsem);
 
 		/* Scrub for replace must not be running in suspended state */
-		ret = btrfs_scrub_cancel(fs_info);
-		ASSERT(ret != -ENOTCONN);
+		btrfs_scrub_cancel(fs_info);
 
 		trans = btrfs_start_transaction(root, 0);
 		if (IS_ERR(trans)) {
@@ -1156,7 +1141,7 @@ int btrfs_dev_replace_cancel(struct btrfs_fs_info *fs_info)
 		ret = btrfs_commit_transaction(trans);
 		WARN_ON(ret);
 
-		btrfs_info_in_rcu(fs_info,
+		btrfs_info(fs_info,
 		"suspended dev_replace from %s (devid %llu) to %s canceled",
 			btrfs_dev_name(src_device), src_device->devid,
 			btrfs_dev_name(tgt_device));
@@ -1260,7 +1245,7 @@ static int btrfs_dev_replace_kthread(void *data)
 
 	progress = btrfs_dev_replace_progress(fs_info);
 	progress = div_u64(progress, 10);
-	btrfs_info_in_rcu(fs_info,
+	btrfs_info(fs_info,
 		"continuing dev_replace from %s (devid %llu) to target %s @%u%%",
 		btrfs_dev_name(dev_replace->srcdev),
 		dev_replace->srcdev->devid,
@@ -1278,16 +1263,16 @@ static int btrfs_dev_replace_kthread(void *data)
 	return 0;
 }
 
-int __pure btrfs_dev_replace_is_ongoing(struct btrfs_dev_replace *dev_replace)
+bool __pure btrfs_dev_replace_is_ongoing(struct btrfs_dev_replace *dev_replace)
 {
 	if (!dev_replace->is_valid)
-		return 0;
+		return false;
 
 	switch (dev_replace->replace_state) {
 	case BTRFS_IOCTL_DEV_REPLACE_STATE_NEVER_STARTED:
 	case BTRFS_IOCTL_DEV_REPLACE_STATE_FINISHED:
 	case BTRFS_IOCTL_DEV_REPLACE_STATE_CANCELED:
-		return 0;
+		return false;
 	case BTRFS_IOCTL_DEV_REPLACE_STATE_STARTED:
 	case BTRFS_IOCTL_DEV_REPLACE_STATE_SUSPENDED:
 		/*
@@ -1302,12 +1287,7 @@ int __pure btrfs_dev_replace_is_ongoing(struct btrfs_dev_replace *dev_replace)
 		 */
 		break;
 	}
-	return 1;
-}
-
-void btrfs_bio_counter_inc_noblocked(struct btrfs_fs_info *fs_info)
-{
-	percpu_counter_inc(&fs_info->dev_replace.bio_counter);
+	return true;
 }
 
 void btrfs_bio_counter_sub(struct btrfs_fs_info *fs_info, s64 amount)