1 files changed, 275 insertions, 124 deletions

diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index 0052ca8264d..6cb82f62cb7 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -28,7 +28,6 @@
 #include <linux/raid/pq.h>
 #include <linux/semaphore.h>
 #include <asm/div64.h>
-#include "compat.h"
 #include "ctree.h"
 #include "extent_map.h"
 #include "disk-io.h"
@@ -41,6 +40,7 @@
 #include "rcu-string.h"
 #include "math.h"
 #include "dev-replace.h"
+#include "sysfs.h"
 
 static int init_first_rw_device(struct btrfs_trans_handle *trans,
 				struct btrfs_root *root,
@@ -126,7 +126,7 @@ static void btrfs_kobject_uevent(struct block_device *bdev,
 
 	ret = kobject_uevent(&disk_to_dev(bdev->bd_disk)->kobj, action);
 	if (ret)
-		pr_warn("Sending event '%d' to kobject: '%s' (%p): failed\n",
+		pr_warn("BTRFS: Sending event '%d' to kobject: '%s' (%p): failed\n",
 			action,
 			kobject_name(&disk_to_dev(bdev->bd_disk)->kobj),
 			&disk_to_dev(bdev->bd_disk)->kobj);
@@ -201,7 +201,7 @@ btrfs_get_bdev_and_sb(const char *device_path, fmode_t flags, void *holder,
 
 	if (IS_ERR(*bdev)) {
 		ret = PTR_ERR(*bdev);
-		printk(KERN_INFO "btrfs: open %s failed\n", device_path);
+		printk(KERN_INFO "BTRFS: open %s failed\n", device_path);
 		goto error;
 	}
 
@@ -416,7 +416,8 @@ loop_lock:
 			device->running_pending = 1;
 
 			spin_unlock(&device->io_lock);
-			btrfs_requeue_work(&device->work);
+			btrfs_queue_work(fs_info->submit_workers,
+					 &device->work);
 			goto done;
 		}
 		/* unplug every 64 requests just for good measure */
@@ -448,6 +449,14 @@ static void pending_bios_fn(struct btrfs_work *work)
 	run_scheduled_bios(device);
 }
 
+/*
+ * Add new device to list of registered devices
+ *
+ * Returns:
+ * 1   - first time device is seen
+ * 0   - device already known
+ * < 0 - error
+ */
 static noinline int device_list_add(const char *path,
 			   struct btrfs_super_block *disk_super,
 			   u64 devid, struct btrfs_fs_devices **fs_devices_ret)
@@ -455,6 +464,7 @@ static noinline int device_list_add(const char *path,
 	struct btrfs_device *device;
 	struct btrfs_fs_devices *fs_devices;
 	struct rcu_string *name;
+	int ret = 0;
 	u64 found_transid = btrfs_super_generation(disk_super);
 
 	fs_devices = find_fsid(disk_super->fsid);
@@ -495,6 +505,7 @@ static noinline int device_list_add(const char *path,
 		fs_devices->num_devices++;
 		mutex_unlock(&fs_devices->device_list_mutex);
 
+		ret = 1;
 		device->fs_devices = fs_devices;
 	} else if (!device->name || strcmp(device->name->str, path)) {
 		name = rcu_string_strdup(path, GFP_NOFS);
@@ -513,7 +524,8 @@ static noinline int device_list_add(const char *path,
 		fs_devices->latest_trans = found_transid;
 	}
 	*fs_devices_ret = fs_devices;
-	return 0;
+
+	return ret;
 }
 
 static struct btrfs_fs_devices *clone_fs_devices(struct btrfs_fs_devices *orig)
@@ -543,12 +555,14 @@ static struct btrfs_fs_devices *clone_fs_devices(struct btrfs_fs_devices *orig)
 		 * This is ok to do without rcu read locked because we hold the
 		 * uuid mutex so nothing we touch in here is going to disappear.
 		 */
-		name = rcu_string_strdup(orig_dev->name->str, GFP_NOFS);
-		if (!name) {
-			kfree(device);
-			goto error;
+		if (orig_dev->name) {
+			name = rcu_string_strdup(orig_dev->name->str, GFP_NOFS);
+			if (!name) {
+				kfree(device);
+				goto error;
+			}
+			rcu_assign_pointer(device->name, name);
 		}
-		rcu_assign_pointer(device->name, name);
 
 		list_add(&device->dev_list, &fs_devices->devices);
 		device->fs_devices = fs_devices;
@@ -666,7 +680,8 @@ static int __btrfs_close_devices(struct btrfs_fs_devices *fs_devices)
 		if (device->bdev)
 			fs_devices->open_devices--;
 
-		if (device->writeable && !device->is_tgtdev_for_dev_replace) {
+		if (device->writeable &&
+		    device->devid != BTRFS_DEV_REPLACE_DEVID) {
 			list_del_init(&device->dev_alloc_list);
 			fs_devices->rw_devices--;
 		}
@@ -796,7 +811,8 @@ static int __btrfs_open_devices(struct btrfs_fs_devices *fs_devices,
 			fs_devices->rotating = 1;
 
 		fs_devices->open_devices++;
-		if (device->writeable && !device->is_tgtdev_for_dev_replace) {
+		if (device->writeable &&
+		    device->devid != BTRFS_DEV_REPLACE_DEVID) {
 			fs_devices->rw_devices++;
 			list_add(&device->dev_alloc_list,
 				 &fs_devices->alloc_list);
@@ -908,17 +924,19 @@ int btrfs_scan_one_device(const char *path, fmode_t flags, void *holder,
 	transid = btrfs_super_generation(disk_super);
 	total_devices = btrfs_super_num_devices(disk_super);
 
-	if (disk_super->label[0]) {
-		if (disk_super->label[BTRFS_LABEL_SIZE - 1])
-			disk_super->label[BTRFS_LABEL_SIZE - 1] = '\0';
-		printk(KERN_INFO "device label %s ", disk_super->label);
-	} else {
-		printk(KERN_INFO "device fsid %pU ", disk_super->fsid);
-	}
-
-	printk(KERN_CONT "devid %llu transid %llu %s\n", devid, transid, path);
-
 	ret = device_list_add(path, disk_super, devid, fs_devices_ret);
+	if (ret > 0) {
+		if (disk_super->label[0]) {
+			if (disk_super->label[BTRFS_LABEL_SIZE - 1])
+				disk_super->label[BTRFS_LABEL_SIZE - 1] = '\0';
+			printk(KERN_INFO "BTRFS: device label %s ", disk_super->label);
+		} else {
+			printk(KERN_INFO "BTRFS: device fsid %pU ", disk_super->fsid);
+		}
+
+		printk(KERN_CONT "devid %llu transid %llu %s\n", devid, transid, path);
+		ret = 0;
+	}
 	if (!ret && fs_devices_ret)
 		(*fs_devices_ret)->total_devices = total_devices;
 
@@ -1437,6 +1455,22 @@ out:
 	return ret;
 }
 
+/*
+ * Function to update ctime/mtime for a given device path.
+ * Mainly used for ctime/mtime based probe like libblkid.
+ */
+static void update_dev_time(char *path_name)
+{
+	struct file *filp;
+
+	filp = filp_open(path_name, O_RDWR, 0);
+	if (!filp)
+		return;
+	file_update_time(filp);
+	filp_close(filp, NULL);
+	return;
+}
+
 static int btrfs_rm_dev_item(struct btrfs_root *root,
 			     struct btrfs_device *device)
 {
@@ -1646,8 +1680,11 @@ int btrfs_rm_device(struct btrfs_root *root, char *device_path)
 	if (device->bdev == root->fs_info->fs_devices->latest_bdev)
 		root->fs_info->fs_devices->latest_bdev = next_device->bdev;
 
-	if (device->bdev)
+	if (device->bdev) {
 		device->fs_devices->open_devices--;
+		/* remove sysfs entry */
+		btrfs_kobj_rm_device(root->fs_info, device);
+	}
 
 	call_rcu(&device->rcu, free_device);
 
@@ -1659,11 +1696,12 @@ int btrfs_rm_device(struct btrfs_root *root, char *device_path)
 		struct btrfs_fs_devices *fs_devices;
 		fs_devices = root->fs_info->fs_devices;
 		while (fs_devices) {
-			if (fs_devices->seed == cur_devices)
+			if (fs_devices->seed == cur_devices) {
+				fs_devices->seed = cur_devices->seed;
 				break;
+			}
 			fs_devices = fs_devices->seed;
 		}
-		fs_devices->seed = cur_devices->seed;
 		cur_devices->seed = NULL;
 		lock_chunks(root);
 		__btrfs_close_devices(cur_devices);
@@ -1679,20 +1717,55 @@ int btrfs_rm_device(struct btrfs_root *root, char *device_path)
 	 * remove it from the devices list and zero out the old super
 	 */
 	if (clear_super && disk_super) {
+		u64 bytenr;
+		int i;
+
 		/* make sure this device isn't detected as part of
 		 * the FS anymore
 		 */
 		memset(&disk_super->magic, 0, sizeof(disk_super->magic));
 		set_buffer_dirty(bh);
 		sync_dirty_buffer(bh);
+
+		/* clear the mirror copies of super block on the disk
+		 * being removed, 0th copy is been taken care above and
+		 * the below would take of the rest
+		 */
+		for (i = 1; i < BTRFS_SUPER_MIRROR_MAX; i++) {
+			bytenr = btrfs_sb_offset(i);
+			if (bytenr + BTRFS_SUPER_INFO_SIZE >=
+					i_size_read(bdev->bd_inode))
+				break;
+
+			brelse(bh);
+			bh = __bread(bdev, bytenr / 4096,
+					BTRFS_SUPER_INFO_SIZE);
+			if (!bh)
+				continue;
+
+			disk_super = (struct btrfs_super_block *)bh->b_data;
+
+			if (btrfs_super_bytenr(disk_super) != bytenr ||
+				btrfs_super_magic(disk_super) != BTRFS_MAGIC) {
+				continue;
+			}
+			memset(&disk_super->magic, 0,
+						sizeof(disk_super->magic));
+			set_buffer_dirty(bh);
+			sync_dirty_buffer(bh);
+		}
 	}
 
 	ret = 0;
 
-	/* Notify udev that device has changed */
-	if (bdev)
+	if (bdev) {
+		/* Notify udev that device has changed */
 		btrfs_kobject_uevent(bdev, KOBJ_CHANGE);
 
+		/* Update ctime/mtime for device path for libblkid */
+		update_dev_time(device_path);
+	}
+
 error_brelse:
 	brelse(bh);
 	if (bdev)
@@ -1715,6 +1788,7 @@ void btrfs_rm_dev_replace_srcdev(struct btrfs_fs_info *fs_info,
 				 struct btrfs_device *srcdev)
 {
 	WARN_ON(!mutex_is_locked(&fs_info->fs_devices->device_list_mutex));
+
 	list_del_rcu(&srcdev->dev_list);
 	list_del_rcu(&srcdev->dev_alloc_list);
 	fs_info->fs_devices->num_devices--;
@@ -1724,9 +1798,13 @@ void btrfs_rm_dev_replace_srcdev(struct btrfs_fs_info *fs_info,
 	}
 	if (srcdev->can_discard)
 		fs_info->fs_devices->num_can_discard--;
-	if (srcdev->bdev)
+	if (srcdev->bdev) {
 		fs_info->fs_devices->open_devices--;
 
+		/* zero out the old super */
+		btrfs_scratch_superblock(srcdev);
+	}
+
 	call_rcu(&srcdev->rcu, free_device);
 }
 
@@ -1807,7 +1885,7 @@ int btrfs_find_device_missing_or_by_path(struct btrfs_root *root,
 		}
 
 		if (!*device) {
-			pr_err("btrfs: no missing device found\n");
+			btrfs_err(root->fs_info, "no missing device found");
 			return -ENOENT;
 		}
 
@@ -1863,7 +1941,6 @@ static int btrfs_prepare_sprout(struct btrfs_root *root)
 	fs_devices->seeding = 0;
 	fs_devices->num_devices = 0;
 	fs_devices->open_devices = 0;
-	fs_devices->total_devices = 0;
 	fs_devices->seed = seed_devices;
 
 	generate_random_uuid(fs_devices->fsid);
@@ -2035,6 +2112,7 @@ int btrfs_init_new_device(struct btrfs_root *root, char *device_path)
 	device->in_fs_metadata = 1;
 	device->is_tgtdev_for_dev_replace = 0;
 	device->mode = FMODE_EXCL;
+	device->dev_stats_valid = 1;
 	set_blocksize(device->bdev, 4096);
 
 	if (seeding_dev) {
@@ -2071,9 +2149,14 @@ int btrfs_init_new_device(struct btrfs_root *root, char *device_path)
 	total_bytes = btrfs_super_num_devices(root->fs_info->super_copy);
 	btrfs_set_super_num_devices(root->fs_info->super_copy,
 				    total_bytes + 1);
+
+	/* add sysfs device entry */
+	btrfs_kobj_add_device(root->fs_info, device);
+
 	mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
 
 	if (seeding_dev) {
+		char fsid_buf[BTRFS_UUID_UNPARSED_SIZE];
 		ret = init_first_rw_device(trans, root, device);
 		if (ret) {
 			btrfs_abort_transaction(trans, root, ret);
@@ -2084,6 +2167,14 @@ int btrfs_init_new_device(struct btrfs_root *root, char *device_path)
 			btrfs_abort_transaction(trans, root, ret);
 			goto error_trans;
 		}
+
+		/* Sprouting would change fsid of the mounted root,
+		 * so rename the fsid on the sysfs
+		 */
+		snprintf(fsid_buf, BTRFS_UUID_UNPARSED_SIZE, "%pU",
+						root->fs_info->fsid);
+		if (kobject_rename(&root->fs_info->super_kobj, fsid_buf))
+			goto error_trans;
 	} else {
 		ret = btrfs_add_device(trans, root, device);
 		if (ret) {
@@ -2125,12 +2216,15 @@ int btrfs_init_new_device(struct btrfs_root *root, char *device_path)
 		ret = btrfs_commit_transaction(trans, root);
 	}
 
+	/* Update ctime/mtime for libblkid */
+	update_dev_time(device_path);
 	return ret;
 
 error_trans:
 	unlock_chunks(root);
 	btrfs_end_transaction(trans, root);
 	rcu_string_free(device->name);
+	btrfs_kobj_rm_device(root->fs_info, device);
 	kfree(device);
 error:
 	blkdev_put(bdev, FMODE_EXCL);
@@ -2202,6 +2296,7 @@ int btrfs_init_dev_replace_tgtdev(struct btrfs_root *root, char *device_path,
 	device->in_fs_metadata = 1;
 	device->is_tgtdev_for_dev_replace = 1;
 	device->mode = FMODE_EXCL;
+	device->dev_stats_valid = 1;
 	set_blocksize(device->bdev, 4096);
 	device->fs_devices = fs_info->fs_devices;
 	list_add(&device->dev_list, &fs_info->fs_devices->devices);
@@ -2468,9 +2563,6 @@ static int btrfs_relocate_chunk(struct btrfs_root *root,
 	remove_extent_mapping(em_tree, em);
 	write_unlock(&em_tree->lock);
 
-	kfree(map);
-	em->bdev = NULL;
-
 	/* once for the tree */
 	free_extent_map(em);
 	/* once for us */
@@ -2544,8 +2636,7 @@ again:
 		failed = 0;
 		retried = true;
 		goto again;
-	} else if (failed && retried) {
-		WARN_ON(1);
+	} else if (WARN_ON(failed && retried)) {
 		ret = -ENOSPC;
 	}
 error:
@@ -2901,6 +2992,16 @@ static int should_balance_chunk(struct btrfs_root *root,
 		return 0;
 	}
 
+	/*
+	 * limited by count, must be the last filter
+	 */
+	if ((bargs->flags & BTRFS_BALANCE_ARGS_LIMIT)) {
+		if (bargs->limit == 0)
+			return 0;
+		else
+			bargs->limit--;
+	}
+
 	return 1;
 }
 
@@ -2923,6 +3024,9 @@ static int __btrfs_balance(struct btrfs_fs_info *fs_info)
 	int ret;
 	int enospc_errors = 0;
 	bool counting = true;
+	u64 limit_data = bctl->data.limit;
+	u64 limit_meta = bctl->meta.limit;
+	u64 limit_sys = bctl->sys.limit;
 
 	/* step one make some room on all the devices */
 	devices = &fs_info->fs_devices->devices;
@@ -2961,6 +3065,11 @@ static int __btrfs_balance(struct btrfs_fs_info *fs_info)
 	memset(&bctl->stat, 0, sizeof(bctl->stat));
 	spin_unlock(&fs_info->balance_lock);
 again:
+	if (!counting) {
+		bctl->data.limit = limit_data;
+		bctl->meta.limit = limit_meta;
+		bctl->sys.limit = limit_sys;
+	}
 	key.objectid = BTRFS_FIRST_CHUNK_TREE_OBJECTID;
 	key.offset = (u64)-1;
 	key.type = BTRFS_CHUNK_ITEM_KEY;
@@ -3045,7 +3154,7 @@ loop:
 error:
 	btrfs_free_path(path);
 	if (enospc_errors) {
-		printk(KERN_INFO "btrfs: %d enospc errors during balance\n",
+		btrfs_info(fs_info, "%d enospc errors during balance",
 		       enospc_errors);
 		if (!ret)
 			ret = -ENOSPC;
@@ -3131,8 +3240,8 @@ int btrfs_balance(struct btrfs_balance_control *bctl,
 		if (!(bctl->flags & BTRFS_BALANCE_DATA) ||
 		    !(bctl->flags & BTRFS_BALANCE_METADATA) ||
 		    memcmp(&bctl->data, &bctl->meta, sizeof(bctl->data))) {
-			printk(KERN_ERR "btrfs: with mixed groups data and "
-			       "metadata balance options must be the same\n");
+			btrfs_err(fs_info, "with mixed groups data and "
+				   "metadata balance options must be the same");
 			ret = -EINVAL;
 			goto out;
 		}
@@ -3158,8 +3267,8 @@ int btrfs_balance(struct btrfs_balance_control *bctl,
 	if ((bctl->data.flags & BTRFS_BALANCE_ARGS_CONVERT) &&
 	    (!alloc_profile_is_valid(bctl->data.target, 1) ||
 	     (bctl->data.target & ~allowed))) {
-		printk(KERN_ERR "btrfs: unable to start balance with target "
-		       "data profile %llu\n",
+		btrfs_err(fs_info, "unable to start balance with target "
+			   "data profile %llu",
 		       bctl->data.target);
 		ret = -EINVAL;
 		goto out;
@@ -3167,8 +3276,8 @@ int btrfs_balance(struct btrfs_balance_control *bctl,
 	if ((bctl->meta.flags & BTRFS_BALANCE_ARGS_CONVERT) &&
 	    (!alloc_profile_is_valid(bctl->meta.target, 1) ||
 	     (bctl->meta.target & ~allowed))) {
-		printk(KERN_ERR "btrfs: unable to start balance with target "
-		       "metadata profile %llu\n",
+		btrfs_err(fs_info,
+			   "unable to start balance with target metadata profile %llu",
 		       bctl->meta.target);
 		ret = -EINVAL;
 		goto out;
@@ -3176,8 +3285,8 @@ int btrfs_balance(struct btrfs_balance_control *bctl,
 	if ((bctl->sys.flags & BTRFS_BALANCE_ARGS_CONVERT) &&
 	    (!alloc_profile_is_valid(bctl->sys.target, 1) ||
 	     (bctl->sys.target & ~allowed))) {
-		printk(KERN_ERR "btrfs: unable to start balance with target "
-		       "system profile %llu\n",
+		btrfs_err(fs_info,
+			   "unable to start balance with target system profile %llu",
 		       bctl->sys.target);
 		ret = -EINVAL;
 		goto out;
@@ -3186,7 +3295,7 @@ int btrfs_balance(struct btrfs_balance_control *bctl,
 	/* allow dup'ed data chunks only in mixed mode */
 	if (!mixed && (bctl->data.flags & BTRFS_BALANCE_ARGS_CONVERT) &&
 	    (bctl->data.target & BTRFS_BLOCK_GROUP_DUP)) {
-		printk(KERN_ERR "btrfs: dup for data is not allowed\n");
+		btrfs_err(fs_info, "dup for data is not allowed");
 		ret = -EINVAL;
 		goto out;
 	}
@@ -3206,11 +3315,10 @@ int btrfs_balance(struct btrfs_balance_control *bctl,
 		     (fs_info->avail_metadata_alloc_bits & allowed) &&
 		     !(bctl->meta.target & allowed))) {
 			if (bctl->flags & BTRFS_BALANCE_FORCE) {
-				printk(KERN_INFO "btrfs: force reducing metadata "
-				       "integrity\n");
+				btrfs_info(fs_info, "force reducing metadata integrity");
 			} else {
-				printk(KERN_ERR "btrfs: balance will reduce metadata "
-				       "integrity, use force if you want this\n");
+				btrfs_err(fs_info, "balance will reduce metadata "
+					   "integrity, use force if you want this");
 				ret = -EINVAL;
 				goto out;
 			}
@@ -3296,7 +3404,7 @@ static int balance_kthread(void *data)
 	mutex_lock(&fs_info->balance_mutex);
 
 	if (fs_info->balance_ctl) {
-		printk(KERN_INFO "btrfs: continuing balance\n");
+		btrfs_info(fs_info, "continuing balance");
 		ret = btrfs_balance(fs_info->balance_ctl, NULL);
 	}
 
@@ -3318,7 +3426,7 @@ int btrfs_resume_balance_async(struct btrfs_fs_info *fs_info)
 	spin_unlock(&fs_info->balance_lock);
 
 	if (btrfs_test_opt(fs_info->tree_root, SKIP_BALANCE)) {
-		printk(KERN_INFO "btrfs: force skipping balance\n");
+		btrfs_info(fs_info, "force skipping balance");
 		return 0;
 	}
 
@@ -3417,6 +3525,9 @@ int btrfs_pause_balance(struct btrfs_fs_info *fs_info)
 
 int btrfs_cancel_balance(struct btrfs_fs_info *fs_info)
 {
+	if (fs_info->sb->s_flags & MS_RDONLY)
+		return -EROFS;
+
 	mutex_lock(&fs_info->balance_mutex);
 	if (!fs_info->balance_ctl) {
 		mutex_unlock(&fs_info->balance_mutex);
@@ -3482,7 +3593,7 @@ static int btrfs_uuid_scan_kthread(void *data)
 	path->keep_locks = 1;
 
 	while (1) {
-		ret = btrfs_search_forward(root, &key, &max_key, path, 0);
+		ret = btrfs_search_forward(root, &key, path, 0);
 		if (ret) {
 			if (ret > 0)
 				ret = 0;
@@ -3533,7 +3644,7 @@ update_tree:
 						  BTRFS_UUID_KEY_SUBVOL,
 						  key.objectid);
 			if (ret < 0) {
-				pr_warn("btrfs: uuid_tree_add failed %d\n",
+				btrfs_warn(fs_info, "uuid_tree_add failed %d",
 					ret);
 				break;
 			}
@@ -3545,7 +3656,7 @@ update_tree:
 						 BTRFS_UUID_KEY_RECEIVED_SUBVOL,
 						  key.objectid);
 			if (ret < 0) {
-				pr_warn("btrfs: uuid_tree_add failed %d\n",
+				btrfs_warn(fs_info, "uuid_tree_add failed %d",
 					ret);
 				break;
 			}
@@ -3580,7 +3691,7 @@ out:
 	if (trans && !IS_ERR(trans))
 		btrfs_end_transaction(trans, fs_info->uuid_root);
 	if (ret)
-		pr_warn("btrfs: btrfs_uuid_scan_kthread failed %d\n", ret);
+		btrfs_warn(fs_info, "btrfs_uuid_scan_kthread failed %d", ret);
 	else
 		fs_info->update_uuid_tree_gen = 1;
 	up(&fs_info->uuid_tree_rescan_sem);
@@ -3644,7 +3755,7 @@ static int btrfs_uuid_rescan_kthread(void *data)
 	 */
 	ret = btrfs_uuid_tree_iterate(fs_info, btrfs_check_uuid_tree_entry);
 	if (ret < 0) {
-		pr_warn("btrfs: iterating uuid_tree failed %d\n", ret);
+		btrfs_warn(fs_info, "iterating uuid_tree failed %d", ret);
 		up(&fs_info->uuid_tree_rescan_sem);
 		return ret;
 	}
@@ -3685,7 +3796,7 @@ int btrfs_create_uuid_tree(struct btrfs_fs_info *fs_info)
 	task = kthread_run(btrfs_uuid_scan_kthread, fs_info, "btrfs-uuid");
 	if (IS_ERR(task)) {
 		/* fs_info->update_uuid_tree_gen remains 0 in all error case */
-		pr_warn("btrfs: failed to start uuid_scan task\n");
+		btrfs_warn(fs_info, "failed to start uuid_scan task");
 		up(&fs_info->uuid_tree_rescan_sem);
 		return PTR_ERR(task);
 	}
@@ -3701,7 +3812,7 @@ int btrfs_check_uuid_tree(struct btrfs_fs_info *fs_info)
 	task = kthread_run(btrfs_uuid_rescan_kthread, fs_info, "btrfs-uuid");
 	if (IS_ERR(task)) {
 		/* fs_info->update_uuid_tree_gen remains 0 in all error case */
-		pr_warn("btrfs: failed to start uuid_rescan task\n");
+		btrfs_warn(fs_info, "failed to start uuid_rescan task");
 		up(&fs_info->uuid_tree_rescan_sem);
 		return PTR_ERR(task);
 	}
@@ -3858,7 +3969,8 @@ static int btrfs_add_system_chunk(struct btrfs_root *root,
 	u8 *ptr;
 
 	array_size = btrfs_super_sys_array_size(super_copy);
-	if (array_size + item_size > BTRFS_SYSTEM_CHUNK_ARRAY_SIZE)
+	if (array_size + item_size + sizeof(disk_key)
+			> BTRFS_SYSTEM_CHUNK_ARRAY_SIZE)
 		return -EFBIG;
 
 	ptr = super_copy->sys_chunk_array + array_size;
@@ -3963,6 +4075,16 @@ static void check_raid56_incompat_flag(struct btrfs_fs_info *info, u64 type)
 	btrfs_set_fs_incompat(info, RAID56);
 }
 
+#define BTRFS_MAX_DEVS(r) ((BTRFS_LEAF_DATA_SIZE(r)		\
+			- sizeof(struct btrfs_item)		\
+			- sizeof(struct btrfs_chunk))		\
+			/ sizeof(struct btrfs_stripe) + 1)
+
+#define BTRFS_MAX_DEVS_SYS_CHUNK ((BTRFS_SYSTEM_CHUNK_ARRAY_SIZE	\
+				- 2 * sizeof(struct btrfs_disk_key)	\
+				- 2 * sizeof(struct btrfs_chunk))	\
+				/ sizeof(struct btrfs_stripe) + 1)
+
 static int __btrfs_alloc_chunk(struct btrfs_trans_handle *trans,
 			       struct btrfs_root *extent_root, u64 start,
 			       u64 type)
@@ -4012,6 +4134,8 @@ static int __btrfs_alloc_chunk(struct btrfs_trans_handle *trans,
 	if (type & BTRFS_BLOCK_GROUP_DATA) {
 		max_stripe_size = 1024 * 1024 * 1024;
 		max_chunk_size = 10 * max_stripe_size;
+		if (!devs_max)
+			devs_max = BTRFS_MAX_DEVS(info->chunk_root);
 	} else if (type & BTRFS_BLOCK_GROUP_METADATA) {
 		/* for larger filesystems, use larger metadata chunks */
 		if (fs_devices->total_rw_bytes > 50ULL * 1024 * 1024 * 1024)
@@ -4019,11 +4143,15 @@ static int __btrfs_alloc_chunk(struct btrfs_trans_handle *trans,
 		else
 			max_stripe_size = 256 * 1024 * 1024;
 		max_chunk_size = max_stripe_size;
+		if (!devs_max)
+			devs_max = BTRFS_MAX_DEVS(info->chunk_root);
 	} else if (type & BTRFS_BLOCK_GROUP_SYSTEM) {
 		max_stripe_size = 32 * 1024 * 1024;
 		max_chunk_size = 2 * max_stripe_size;
+		if (!devs_max)
+			devs_max = BTRFS_MAX_DEVS_SYS_CHUNK;
 	} else {
-		printk(KERN_ERR "btrfs: invalid chunk type 0x%llx requested\n",
+		btrfs_err(info, "invalid chunk type 0x%llx requested",
 		       type);
 		BUG_ON(1);
 	}
@@ -4055,7 +4183,7 @@ static int __btrfs_alloc_chunk(struct btrfs_trans_handle *trans,
 
 		if (!device->writeable) {
 			WARN(1, KERN_ERR
-			       "btrfs: read-only device in alloc_list\n");
+			       "BTRFS: read-only device in alloc_list\n");
 			continue;
 		}
 
@@ -4190,9 +4318,11 @@ static int __btrfs_alloc_chunk(struct btrfs_trans_handle *trans,
 
 	em = alloc_extent_map();
 	if (!em) {
+		kfree(map);
 		ret = -ENOMEM;
 		goto error;
 	}
+	set_bit(EXTENT_FLAG_FS_MAPPING, &em->flags);
 	em->bdev = (struct block_device *)map;
 	em->start = start;
 	em->len = num_bytes;
@@ -4235,7 +4365,6 @@ error_del_extent:
 	/* One for the tree reference */
 	free_extent_map(em);
 error:
-	kfree(map);
 	kfree(devices_info);
 	return ret;
 }
@@ -4271,7 +4400,7 @@ int btrfs_finish_chunk_alloc(struct btrfs_trans_handle *trans,
 
 	if (em->start != chunk_offset || em->len != chunk_size) {
 		btrfs_crit(extent_root->fs_info, "found a bad mapping, wanted"
-			  " %Lu-%Lu, found %Lu-%Lu\n", chunk_offset,
+			  " %Lu-%Lu, found %Lu-%Lu", chunk_offset,
 			  chunk_size, em->start, em->len);
 		free_extent_map(em);
 		return -EINVAL;
@@ -4447,7 +4576,6 @@ void btrfs_mapping_tree_free(struct btrfs_mapping_tree *tree)
 		write_unlock(&tree->map_tree.lock);
 		if (!em)
 			break;
-		kfree(em->bdev);
 		/* once for us */
 		free_extent_map(em);
 		/* once for the tree */
@@ -4473,15 +4601,16 @@ int btrfs_num_copies(struct btrfs_fs_info *fs_info, u64 logical, u64 len)
 	 * and exit, so return 1 so the callers don't try to use other copies.
 	 */
 	if (!em) {
-		btrfs_crit(fs_info, "No mapping for %Lu-%Lu\n", logical,
+		btrfs_crit(fs_info, "No mapping for %Lu-%Lu", logical,
 			    logical+len);
 		return 1;
 	}
 
 	if (em->start > logical || em->start + em->len < logical) {
 		btrfs_crit(fs_info, "Invalid mapping for %Lu-%Lu, got "
-			    "%Lu-%Lu\n", logical, logical+len, em->start,
+			    "%Lu-%Lu", logical, logical+len, em->start,
 			    em->start + em->len);
+		free_extent_map(em);
 		return 1;
 	}
 
@@ -4660,8 +4789,9 @@ static int __btrfs_map_block(struct btrfs_fs_info *fs_info, int rw,
 
 	if (em->start > logical || em->start + em->len < logical) {
 		btrfs_crit(fs_info, "found a bad mapping, wanted %Lu, "
-			   "found %Lu-%Lu\n", logical, em->start,
+			   "found %Lu-%Lu", logical, em->start,
 			   em->start + em->len);
+		free_extent_map(em);
 		return -EINVAL;
 	}
 
@@ -4889,7 +5019,7 @@ static int __btrfs_map_block(struct btrfs_fs_info *fs_info, int rw,
 			num_stripes = map->num_stripes;
 			max_errors = nr_parity_stripes(map);
 
-			raid_map = kmalloc(sizeof(u64) * num_stripes,
+			raid_map = kmalloc_array(num_stripes, sizeof(u64),
 					   GFP_NOFS);
 			if (!raid_map) {
 				ret = -ENOMEM;
@@ -5181,13 +5311,13 @@ int btrfs_rmap_block(struct btrfs_mapping_tree *map_tree,
 	read_unlock(&em_tree->lock);
 
 	if (!em) {
-		printk(KERN_ERR "btrfs: couldn't find em for chunk %Lu\n",
+		printk(KERN_ERR "BTRFS: couldn't find em for chunk %Lu\n",
 		       chunk_start);
 		return -EIO;
 	}
 
 	if (em->start != chunk_start) {
-		printk(KERN_ERR "btrfs: bad chunk start, em=%Lu, wanted=%Lu\n",
+		printk(KERN_ERR "BTRFS: bad chunk start, em=%Lu, wanted=%Lu\n",
 		       em->start, chunk_start);
 		free_extent_map(em);
 		return -EIO;
@@ -5249,9 +5379,19 @@ int btrfs_rmap_block(struct btrfs_mapping_tree *map_tree,
 	return 0;
 }
 
+static inline void btrfs_end_bbio(struct btrfs_bio *bbio, struct bio *bio, int err)
+{
+	if (likely(bbio->flags & BTRFS_BIO_ORIG_BIO_SUBMITTED))
+		bio_endio_nodec(bio, err);
+	else
+		bio_endio(bio, err);
+	kfree(bbio);
+}
+
 static void btrfs_end_bio(struct bio *bio, int err)
 {
 	struct btrfs_bio *bbio = bio->bi_private;
+	struct btrfs_device *dev = bbio->stripes[0].dev;
 	int is_orig_bio = 0;
 
 	if (err) {
@@ -5259,7 +5399,6 @@ static void btrfs_end_bio(struct bio *bio, int err)
 		if (err == -EIO || err == -EREMOTEIO) {
 			unsigned int stripe_index =
 				btrfs_io_bio(bio)->stripe_index;
-			struct btrfs_device *dev;
 
 			BUG_ON(stripe_index >= bbio->num_stripes);
 			dev = bbio->stripes[stripe_index].dev;
@@ -5281,11 +5420,14 @@ static void btrfs_end_bio(struct bio *bio, int err)
 	if (bio == bbio->orig_bio)
 		is_orig_bio = 1;
 
+	btrfs_bio_counter_dec(bbio->fs_info);
+
 	if (atomic_dec_and_test(&bbio->stripes_pending)) {
 		if (!is_orig_bio) {
 			bio_put(bio);
 			bio = bbio->orig_bio;
 		}
+
 		bio->bi_private = bbio->private;
 		bio->bi_end_io = bbio->end_io;
 		btrfs_io_bio(bio)->mirror_num = bbio->mirror_num;
@@ -5302,21 +5444,13 @@ static void btrfs_end_bio(struct bio *bio, int err)
 			set_bit(BIO_UPTODATE, &bio->bi_flags);
 			err = 0;
 		}
-		kfree(bbio);
 
-		bio_endio(bio, err);
+		btrfs_end_bbio(bbio, bio, err);
 	} else if (!is_orig_bio) {
 		bio_put(bio);
 	}
 }
 
-struct async_sched {
-	struct bio *bio;
-	int rw;
-	struct btrfs_fs_info *info;
-	struct btrfs_work work;
-};
-
 /*
  * see run_scheduled_bios for a description of why bios are collected for
  * async submit.
@@ -5373,8 +5507,8 @@ static noinline void btrfs_schedule_bio(struct btrfs_root *root,
 	spin_unlock(&device->io_lock);
 
 	if (should_queue)
-		btrfs_queue_worker(&root->fs_info->submit_workers,
-				   &device->work);
+		btrfs_queue_work(root->fs_info->submit_workers,
+				 &device->work);
 }
 
 static int bio_size_ok(struct block_device *bdev, struct bio *bio,
@@ -5382,17 +5516,15 @@ static int bio_size_ok(struct block_device *bdev, struct bio *bio,
 {
 	struct bio_vec *prev;
 	struct request_queue *q = bdev_get_queue(bdev);
-	unsigned short max_sectors = queue_max_sectors(q);
+	unsigned int max_sectors = queue_max_sectors(q);
 	struct bvec_merge_data bvm = {
 		.bi_bdev = bdev,
 		.bi_sector = sector,
 		.bi_rw = bio->bi_rw,
 	};
 
-	if (bio->bi_vcnt == 0) {
-		WARN_ON(1);
+	if (WARN_ON(bio->bi_vcnt == 0))
 		return 1;
-	}
 
 	prev = &bio->bi_io_vec[bio->bi_vcnt - 1];
 	if (bio_sectors(bio) > max_sectors)
@@ -5401,7 +5533,7 @@ static int bio_size_ok(struct block_device *bdev, struct bio *bio,
 	if (!q->merge_bvec_fn)
 		return 1;
 
-	bvm.bi_size = bio->bi_size - prev->bv_len;
+	bvm.bi_size = bio->bi_iter.bi_size - prev->bv_len;
 	if (q->merge_bvec_fn(q, &bvm, prev) < prev->bv_len)
 		return 0;
 	return 1;
@@ -5416,7 +5548,7 @@ static void submit_stripe_bio(struct btrfs_root *root, struct btrfs_bio *bbio,
 	bio->bi_private = bbio;
 	btrfs_io_bio(bio)->stripe_index = dev_nr;
 	bio->bi_end_io = btrfs_end_bio;
-	bio->bi_sector = physical >> 9;
+	bio->bi_iter.bi_sector = physical >> 9;
 #ifdef DEBUG
 	{
 		struct rcu_string *name;
@@ -5431,6 +5563,9 @@ static void submit_stripe_bio(struct btrfs_root *root, struct btrfs_bio *bbio,
 	}
 #endif
 	bio->bi_bdev = dev->bdev;
+
+	btrfs_bio_counter_inc_noblocked(root->fs_info);
+
 	if (async)
 		btrfs_schedule_bio(root, dev, rw, bio);
 	else
@@ -5454,7 +5589,7 @@ again:
 	while (bvec <= (first_bio->bi_io_vec + first_bio->bi_vcnt - 1)) {
 		if (bio_add_page(bio, bvec->bv_page, bvec->bv_len,
 				 bvec->bv_offset) < bvec->bv_len) {
-			u64 len = bio->bi_size;
+			u64 len = bio->bi_iter.bi_size;
 
 			atomic_inc(&bbio->stripes_pending);
 			submit_stripe_bio(root, bbio, bio, physical, dev_nr,
@@ -5473,12 +5608,15 @@ static void bbio_error(struct btrfs_bio *bbio, struct bio *bio, u64 logical)
 {
 	atomic_inc(&bbio->error);
 	if (atomic_dec_and_test(&bbio->stripes_pending)) {
+		/* Shoud be the original bio. */
+		WARN_ON(bio != bbio->orig_bio);
+
 		bio->bi_private = bbio->private;
 		bio->bi_end_io = bbio->end_io;
 		btrfs_io_bio(bio)->mirror_num = bbio->mirror_num;
-		bio->bi_sector = logical >> 9;
-		kfree(bbio);
-		bio_endio(bio, -EIO);
+		bio->bi_iter.bi_sector = logical >> 9;
+
+		btrfs_end_bbio(bbio, bio, -EIO);
 	}
 }
 
@@ -5487,7 +5625,7 @@ int btrfs_map_bio(struct btrfs_root *root, int rw, struct bio *bio,
 {
 	struct btrfs_device *dev;
 	struct bio *first_bio = bio;
-	u64 logical = (u64)bio->bi_sector << 9;
+	u64 logical = (u64)bio->bi_iter.bi_sector << 9;
 	u64 length = 0;
 	u64 map_length;
 	u64 *raid_map = NULL;
@@ -5496,31 +5634,41 @@ int btrfs_map_bio(struct btrfs_root *root, int rw, struct bio *bio,
 	int total_devs = 1;
 	struct btrfs_bio *bbio = NULL;
 
-	length = bio->bi_size;
+	length = bio->bi_iter.bi_size;
 	map_length = length;
 
+	btrfs_bio_counter_inc_blocked(root->fs_info);
 	ret = __btrfs_map_block(root->fs_info, rw, logical, &map_length, &bbio,
 			      mirror_num, &raid_map);
-	if (ret) /* -ENOMEM */
+	if (ret) {
+		btrfs_bio_counter_dec(root->fs_info);
 		return ret;
+	}
 
 	total_devs = bbio->num_stripes;
 	bbio->orig_bio = first_bio;
 	bbio->private = first_bio->bi_private;
 	bbio->end_io = first_bio->bi_end_io;
+	bbio->fs_info = root->fs_info;
 	atomic_set(&bbio->stripes_pending, bbio->num_stripes);
 
 	if (raid_map) {
 		/* In this case, map_length has been set to the length of
 		   a single stripe; not the whole write */
 		if (rw & WRITE) {
-			return raid56_parity_write(root, bio, bbio,
-						   raid_map, map_length);
+			ret = raid56_parity_write(root, bio, bbio,
+						  raid_map, map_length);
 		} else {
-			return raid56_parity_recover(root, bio, bbio,
-						     raid_map, map_length,
-						     mirror_num);
+			ret = raid56_parity_recover(root, bio, bbio,
+						    raid_map, map_length,
+						    mirror_num);
 		}
+		/*
+		 * FIXME, replace dosen't support raid56 yet, please fix
+		 * it in the future.
+		 */
+		btrfs_bio_counter_dec(root->fs_info);
+		return ret;
 	}
 
 	if (map_length < length) {
@@ -5555,6 +5703,7 @@ int btrfs_map_bio(struct btrfs_root *root, int rw, struct bio *bio,
 			BUG_ON(!bio); /* -ENOMEM */
 		} else {
 			bio = first_bio;
+			bbio->flags |= BTRFS_BIO_ORIG_BIO_SUBMITTED;
 		}
 
 		submit_stripe_bio(root, bbio, bio,
@@ -5562,6 +5711,7 @@ int btrfs_map_bio(struct btrfs_root *root, int rw, struct bio *bio,
 				  async_submit);
 		dev_nr++;
 	}
+	btrfs_bio_counter_dec(root->fs_info);
 	return 0;
 }
 
@@ -5625,10 +5775,8 @@ struct btrfs_device *btrfs_alloc_device(struct btrfs_fs_info *fs_info,
 	struct btrfs_device *dev;
 	u64 tmp;
 
-	if (!devid && !fs_info) {
-		WARN_ON(1);
+	if (WARN_ON(!devid && !fs_info))
 		return ERR_PTR(-EINVAL);
-	}
 
 	dev = __alloc_device();
 	if (IS_ERR(dev))
@@ -5652,7 +5800,7 @@ struct btrfs_device *btrfs_alloc_device(struct btrfs_fs_info *fs_info,
 	else
 		generate_random_uuid(dev->uuid);
 
-	dev->work.func = pending_bios_fn;
+	btrfs_init_work(&dev->work, pending_bios_fn, NULL, NULL);
 
 	return dev;
 }
@@ -5697,6 +5845,7 @@ static int read_one_chunk(struct btrfs_root *root, struct btrfs_key *key,
 		return -ENOMEM;
 	}
 
+	set_bit(EXTENT_FLAG_FS_MAPPING, &em->flags);
 	em->bdev = (struct block_device *)map;
 	em->start = logical;
 	em->len = length;
@@ -5721,7 +5870,6 @@ static int read_one_chunk(struct btrfs_root *root, struct btrfs_key *key,
 		map->stripes[i].dev = btrfs_find_device(root->fs_info, devid,
 							uuid, NULL);
 		if (!map->stripes[i].dev && !btrfs_test_opt(root, DEGRADED)) {
-			kfree(map);
 			free_extent_map(em);
 			return -EIO;
 		}
@@ -5729,7 +5877,6 @@ static int read_one_chunk(struct btrfs_root *root, struct btrfs_key *key,
 			map->stripes[i].dev =
 				add_missing_dev(root, devid, uuid);
 			if (!map->stripes[i].dev) {
-				kfree(map);
 				free_extent_map(em);
 				return -EIO;
 			}
@@ -6021,10 +6168,14 @@ void btrfs_init_devices_late(struct btrfs_fs_info *fs_info)
 	struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
 	struct btrfs_device *device;
 
-	mutex_lock(&fs_devices->device_list_mutex);
-	list_for_each_entry(device, &fs_devices->devices, dev_list)
-		device->dev_root = fs_info->dev_root;
-	mutex_unlock(&fs_devices->device_list_mutex);
+	while (fs_devices) {
+		mutex_lock(&fs_devices->device_list_mutex);
+		list_for_each_entry(device, &fs_devices->devices, dev_list)
+			device->dev_root = fs_info->dev_root;
+		mutex_unlock(&fs_devices->device_list_mutex);
+
+		fs_devices = fs_devices->seed;
+	}
 }
 
 static void __btrfs_reset_dev_stats(struct btrfs_device *dev)
@@ -6115,7 +6266,8 @@ static int update_dev_stat_item(struct btrfs_trans_handle *trans,
 	BUG_ON(!path);
 	ret = btrfs_search_slot(trans, dev_root, &key, path, -1, 1);
 	if (ret < 0) {
-		printk_in_rcu(KERN_WARNING "btrfs: error %d while searching for dev_stats item for device %s!\n",
+		printk_in_rcu(KERN_WARNING "BTRFS: "
+			"error %d while searching for dev_stats item for device %s!\n",
 			      ret, rcu_str_deref(device->name));
 		goto out;
 	}
@@ -6125,7 +6277,8 @@ static int update_dev_stat_item(struct btrfs_trans_handle *trans,
 		/* need to delete old one and insert a new one */
 		ret = btrfs_del_item(trans, dev_root, path);
 		if (ret != 0) {
-			printk_in_rcu(KERN_WARNING "btrfs: delete too small dev_stats item for device %s failed %d!\n",
+			printk_in_rcu(KERN_WARNING "BTRFS: "
+				"delete too small dev_stats item for device %s failed %d!\n",
 				      rcu_str_deref(device->name), ret);
 			goto out;
 		}
@@ -6138,7 +6291,8 @@ static int update_dev_stat_item(struct btrfs_trans_handle *trans,
 		ret = btrfs_insert_empty_item(trans, dev_root, path,
 					      &key, sizeof(*ptr));
 		if (ret < 0) {
-			printk_in_rcu(KERN_WARNING "btrfs: insert dev_stats item for device %s failed %d!\n",
+			printk_in_rcu(KERN_WARNING "BTRFS: "
+					  "insert dev_stats item for device %s failed %d!\n",
 				      rcu_str_deref(device->name), ret);
 			goto out;
 		}
@@ -6191,16 +6345,14 @@ static void btrfs_dev_stat_print_on_error(struct btrfs_device *dev)
 {
 	if (!dev->dev_stats_valid)
 		return;
-	printk_ratelimited_in_rcu(KERN_ERR
-			   "btrfs: bdev %s errs: wr %u, rd %u, flush %u, corrupt %u, gen %u\n",
+	printk_ratelimited_in_rcu(KERN_ERR "BTRFS: "
+			   "bdev %s errs: wr %u, rd %u, flush %u, corrupt %u, gen %u\n",
 			   rcu_str_deref(dev->name),
 			   btrfs_dev_stat_read(dev, BTRFS_DEV_STAT_WRITE_ERRS),
 			   btrfs_dev_stat_read(dev, BTRFS_DEV_STAT_READ_ERRS),
 			   btrfs_dev_stat_read(dev, BTRFS_DEV_STAT_FLUSH_ERRS),
-			   btrfs_dev_stat_read(dev,
-					       BTRFS_DEV_STAT_CORRUPTION_ERRS),
-			   btrfs_dev_stat_read(dev,
-					       BTRFS_DEV_STAT_GENERATION_ERRS));
+			   btrfs_dev_stat_read(dev, BTRFS_DEV_STAT_CORRUPTION_ERRS),
+			   btrfs_dev_stat_read(dev, BTRFS_DEV_STAT_GENERATION_ERRS));
 }
 
 static void btrfs_dev_stat_print_on_load(struct btrfs_device *dev)
@@ -6213,7 +6365,8 @@ static void btrfs_dev_stat_print_on_load(struct btrfs_device *dev)
 	if (i == BTRFS_DEV_STAT_VALUES_MAX)
 		return; /* all values == 0, suppress message */
 
-	printk_in_rcu(KERN_INFO "btrfs: bdev %s errs: wr %u, rd %u, flush %u, corrupt %u, gen %u\n",
+	printk_in_rcu(KERN_INFO "BTRFS: "
+		   "bdev %s errs: wr %u, rd %u, flush %u, corrupt %u, gen %u\n",
 	       rcu_str_deref(dev->name),
 	       btrfs_dev_stat_read(dev, BTRFS_DEV_STAT_WRITE_ERRS),
 	       btrfs_dev_stat_read(dev, BTRFS_DEV_STAT_READ_ERRS),
@@ -6234,12 +6387,10 @@ int btrfs_get_dev_stats(struct btrfs_root *root,
 	mutex_unlock(&fs_devices->device_list_mutex);
 
 	if (!dev) {
-		printk(KERN_WARNING
-		       "btrfs: get dev_stats failed, device not found\n");
+		btrfs_warn(root->fs_info, "get dev_stats failed, device not found");
 		return -ENODEV;
 	} else if (!dev->dev_stats_valid) {
-		printk(KERN_WARNING
-		       "btrfs: get dev_stats failed, not yet valid\n");
+		btrfs_warn(root->fs_info, "get dev_stats failed, not yet valid");
 		return -ENODEV;
 	} else if (stats->flags & BTRFS_DEV_STATS_RESET) {
 		for (i = 0; i < BTRFS_DEV_STAT_VALUES_MAX; i++) {