1 files changed, 19 insertions, 7 deletions

diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index 5cce6aa74012..5cbb7f4b1672 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -1431,7 +1431,7 @@ int btrfs_rm_device(struct btrfs_root *root, char *device_path)
                 }
         } else {
                 ret = btrfs_get_bdev_and_sb(device_path,
-                                            FMODE_READ | FMODE_EXCL,
+                                            FMODE_WRITE | FMODE_EXCL,
                                             root->fs_info->bdev_holder, 0,
                                             &bdev, &bh);
                 if (ret)
@@ -1556,7 +1556,8 @@ int btrfs_rm_device(struct btrfs_root *root, char *device_path)
         ret = 0;
 
         /* Notify udev that device has changed */
-        btrfs_kobject_uevent(bdev, KOBJ_CHANGE);
+        if (bdev)
+                btrfs_kobject_uevent(bdev, KOBJ_CHANGE);
 
 error_brelse:
         brelse(bh);
@@ -2614,7 +2615,14 @@ static int chunk_usage_filter(struct btrfs_fs_info *fs_info, u64 chunk_offset,
         cache = btrfs_lookup_block_group(fs_info, chunk_offset);
         chunk_used = btrfs_block_group_used(&cache->item);
 
-        user_thresh = div_factor_fine(cache->key.offset, bargs->usage);
+        if (bargs->usage == 0)
+                user_thresh = 0;
+        else if (bargs->usage > 100)
+                user_thresh = cache->key.offset;
+        else
+                user_thresh = div_factor_fine(cache->key.offset,
+                                              bargs->usage);
+
         if (chunk_used < user_thresh)
                 ret = 0;
 
@@ -2959,6 +2967,8 @@ static void __cancel_balance(struct btrfs_fs_info *fs_info)
         unset_balance_control(fs_info);
         ret = del_balance_item(fs_info->tree_root);
         BUG_ON(ret);
+
+        atomic_set(&fs_info->mutually_exclusive_operation_running, 0);
 }
 
 void update_ioctl_balance_args(struct btrfs_fs_info *fs_info, int lock,
@@ -3138,8 +3148,10 @@ int btrfs_balance(struct btrfs_balance_control *bctl,
 out:
         if (bctl->flags & BTRFS_BALANCE_RESUME)
                 __cancel_balance(fs_info);
-        else
+        else {
                 kfree(bctl);
+                atomic_set(&fs_info->mutually_exclusive_operation_running, 0);
+        }
         return ret;
 }
 
@@ -3156,7 +3168,6 @@ static int balance_kthread(void *data)
                 ret = btrfs_balance(fs_info->balance_ctl, NULL);
         }
 
-        atomic_set(&fs_info->mutually_exclusive_operation_running, 0);
         mutex_unlock(&fs_info->balance_mutex);
         mutex_unlock(&fs_info->volume_mutex);
 
@@ -3179,7 +3190,6 @@ int btrfs_resume_balance_async(struct btrfs_fs_info *fs_info)
                 return 0;
         }
 
-        WARN_ON(atomic_xchg(&fs_info->mutually_exclusive_operation_running, 1));
         tsk = kthread_run(balance_kthread, fs_info, "btrfs-balance");
         if (IS_ERR(tsk))
                 return PTR_ERR(tsk);
@@ -3233,6 +3243,8 @@ int btrfs_recover_balance(struct btrfs_fs_info *fs_info)
         btrfs_balance_sys(leaf, item, &disk_bargs);
         btrfs_disk_balance_args_to_cpu(&bctl->sys, &disk_bargs);
 
+        WARN_ON(atomic_xchg(&fs_info->mutually_exclusive_operation_running, 1));
+
         mutex_lock(&fs_info->volume_mutex);
         mutex_lock(&fs_info->balance_mutex);
 
@@ -3496,7 +3508,7 @@ struct btrfs_raid_attr btrfs_raid_array[BTRFS_NR_RAID_TYPES] = {
         { 1, 1, 2, 2, 2, 2 /* raid1 */ },
         { 1, 2, 1, 1, 1, 2 /* dup */ },
         { 1, 1, 0, 2, 1, 1 /* raid0 */ },
-        { 1, 1, 0, 1, 1, 1 /* single */ },
+        { 1, 1, 1, 1, 1, 1 /* single */ },
 };
 
 static int __btrfs_alloc_chunk(struct btrfs_trans_handle *trans,