1 files changed, 13 insertions, 18 deletions

diff --git a/fs/btrfs/dev-replace.c b/fs/btrfs/dev-replace.c
index ee0989c7e3a9..6b2e9aa83ffa 100644
--- a/fs/btrfs/dev-replace.c
+++ b/fs/btrfs/dev-replace.c
@@ -201,7 +201,7 @@ static int btrfs_init_dev_replace_tgtdev(struct btrfs_fs_info *fs_info,
                 return PTR_ERR(bdev);
         }
 
-        filemap_write_and_wait(bdev->bd_inode->i_mapping);
+        sync_blockdev(bdev);
 
         devices = &fs_info->fs_devices->devices;
         list_for_each_entry(device, devices, dev_list) {
@@ -237,7 +237,6 @@ static int btrfs_init_dev_replace_tgtdev(struct btrfs_fs_info *fs_info,
         }
         rcu_assign_pointer(device->name, name);
 
-        mutex_lock(&fs_info->fs_devices->device_list_mutex);
         set_bit(BTRFS_DEV_STATE_WRITEABLE, &device->dev_state);
         device->generation = 0;
         device->io_width = fs_info->sectorsize;
@@ -256,6 +255,8 @@ static int btrfs_init_dev_replace_tgtdev(struct btrfs_fs_info *fs_info,
         device->dev_stats_valid = 1;
         set_blocksize(device->bdev, BTRFS_BDEV_BLOCKSIZE);
         device->fs_devices = fs_info->fs_devices;
+
+        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++;
@@ -399,7 +400,6 @@ static int btrfs_dev_replace_start(struct btrfs_fs_info *fs_info,
         int ret;
         struct btrfs_device *tgt_device = NULL;
         struct btrfs_device *src_device = NULL;
-        bool need_unlock;
 
         src_device = btrfs_find_device_by_devspec(fs_info, srcdevid,
                                                   srcdev_name);
@@ -413,11 +413,6 @@ static int btrfs_dev_replace_start(struct btrfs_fs_info *fs_info,
                 return -ETXTBSY;
         }
 
-        ret = btrfs_init_dev_replace_tgtdev(fs_info, tgtdev_name,
-                                            src_device, &tgt_device);
-        if (ret)
-                return ret;
-
         /*
          * Here we commit the transaction to make sure commit_total_bytes
          * of all the devices are updated.
@@ -431,7 +426,11 @@ static int btrfs_dev_replace_start(struct btrfs_fs_info *fs_info,
                 return PTR_ERR(trans);
         }
 
-        need_unlock = true;
+        ret = btrfs_init_dev_replace_tgtdev(fs_info, tgtdev_name,
+                                            src_device, &tgt_device);
+        if (ret)
+                return ret;
+
         down_write(&dev_replace->rwsem);
         switch (dev_replace->replace_state) {
         case BTRFS_IOCTL_DEV_REPLACE_STATE_NEVER_STARTED:
@@ -442,11 +441,11 @@ static int btrfs_dev_replace_start(struct btrfs_fs_info *fs_info,
         case BTRFS_IOCTL_DEV_REPLACE_STATE_SUSPENDED:
                 ASSERT(0);
                 ret = BTRFS_IOCTL_DEV_REPLACE_RESULT_ALREADY_STARTED;
+                up_write(&dev_replace->rwsem);
                 goto leave;
         }
 
         dev_replace->cont_reading_from_srcdev_mode = read_src;
-        WARN_ON(!src_device);
         dev_replace->srcdev = src_device;
         dev_replace->tgtdev = tgt_device;
 
@@ -471,7 +470,6 @@ static int btrfs_dev_replace_start(struct btrfs_fs_info *fs_info,
         atomic64_set(&dev_replace->num_write_errors, 0);
         atomic64_set(&dev_replace->num_uncorrectable_read_errors, 0);
         up_write(&dev_replace->rwsem);
-        need_unlock = false;
 
         ret = btrfs_sysfs_add_device_link(tgt_device->fs_devices, tgt_device);
         if (ret)
@@ -479,16 +477,16 @@ static int btrfs_dev_replace_start(struct btrfs_fs_info *fs_info,
 
         btrfs_wait_ordered_roots(fs_info, U64_MAX, 0, (u64)-1);
 
-        /* force writing the updated state information to disk */
-        trans = btrfs_start_transaction(root, 0);
+        /* Commit dev_replace state and reserve 1 item for it. */
+        trans = btrfs_start_transaction(root, 1);
         if (IS_ERR(trans)) {
                 ret = PTR_ERR(trans);
-                need_unlock = true;
                 down_write(&dev_replace->rwsem);
                 dev_replace->replace_state =
                         BTRFS_IOCTL_DEV_REPLACE_STATE_NEVER_STARTED;
                 dev_replace->srcdev = NULL;
                 dev_replace->tgtdev = NULL;
+                up_write(&dev_replace->rwsem);
                 goto leave;
         }
 
@@ -510,8 +508,6 @@ static int btrfs_dev_replace_start(struct btrfs_fs_info *fs_info,
         return ret;
 
 leave:
-        if (need_unlock)
-                up_write(&dev_replace->rwsem);
         btrfs_destroy_dev_replace_tgtdev(tgt_device);
         return ret;
 }
@@ -678,7 +674,6 @@ static int btrfs_dev_replace_finishing(struct btrfs_fs_info *fs_info,
         btrfs_device_set_disk_total_bytes(tgt_device,
                                           src_device->disk_total_bytes);
         btrfs_device_set_bytes_used(tgt_device, src_device->bytes_used);
-        tgt_device->commit_total_bytes = src_device->commit_total_bytes;
         tgt_device->commit_bytes_used = src_device->bytes_used;
 
         btrfs_assign_next_active_device(src_device, tgt_device);
@@ -728,7 +723,7 @@ 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.map_tree;
+        struct extent_map_tree *em_tree = &fs_info->mapping_tree;
         struct extent_map *em;
         struct map_lookup *map;
         u64 start = 0;