1 files changed, 4 insertions, 0 deletions

diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
index 6846ededfe95..eda330df45a4 100644
--- a/fs/btrfs/super.c
+++ b/fs/btrfs/super.c
@@ -519,7 +519,9 @@ int btrfs_parse_options(struct btrfs_root *root, char *options)
                 case Opt_alloc_start:
                         num = match_strdup(&args[0]);
                         if (num) {
+                                mutex_lock(&info->chunk_mutex);
                                 info->alloc_start = memparse(num, NULL);
+                                mutex_unlock(&info->chunk_mutex);
                                 kfree(num);
                                 printk(KERN_INFO
                                         "btrfs: allocations start at %llu\n",
@@ -1289,7 +1291,9 @@ restore:
         fs_info->mount_opt = old_opts;
         fs_info->compress_type = old_compress_type;
         fs_info->max_inline = old_max_inline;
+        mutex_lock(&fs_info->chunk_mutex);
         fs_info->alloc_start = old_alloc_start;
+        mutex_unlock(&fs_info->chunk_mutex);
         btrfs_resize_thread_pool(fs_info,
                 old_thread_pool_size, fs_info->thread_pool_size);
         fs_info->metadata_ratio = old_metadata_ratio;