Btrfs: fix block group ->space_info null pointer dereference

[uclinux-h8/linux.git] / fs / btrfs / extent-tree.c

diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 0ec3acd..1cbc71d 100644 (file)
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -3693,7 +3693,8 @@ static int update_space_info(struct btrfs_fs_info *info, u64 flags,
                found->disk_total += total_bytes * factor;
                found->bytes_used += bytes_used;
                found->disk_used += bytes_used * factor;
-               found->full = 0;
+               if (total_bytes > 0)
+                       found->full = 0;
                spin_unlock(&found->lock);
                *space_info = found;
                return 0;
@@ -3721,7 +3722,10 @@ static int update_space_info(struct btrfs_fs_info *info, u64 flags,
        found->bytes_reserved = 0;
        found->bytes_readonly = 0;
        found->bytes_may_use = 0;
-       found->full = 0;
+       if (total_bytes > 0)
+               found->full = 0;
+       else
+               found->full = 1;
        found->force_alloc = CHUNK_ALLOC_NO_FORCE;
        found->chunk_alloc = 0;
        found->flush = 0;
@@ -9562,6 +9566,19 @@ int btrfs_make_block_group(struct btrfs_trans_handle *trans,
 
        free_excluded_extents(root, cache);
 
+       /*
+        * Call to ensure the corresponding space_info object is created and
+        * assigned to our block group, but don't update its counters just yet.
+        * We want our bg to be added to the rbtree with its ->space_info set.
+        */
+       ret = update_space_info(root->fs_info, cache->flags, 0, 0,
+                               &cache->space_info);
+       if (ret) {
+               btrfs_remove_free_space_cache(cache);
+               btrfs_put_block_group(cache);
+               return ret;
+       }
+
        ret = btrfs_add_block_group_cache(root->fs_info, cache);
        if (ret) {
                btrfs_remove_free_space_cache(cache);
@@ -9569,6 +9586,10 @@ int btrfs_make_block_group(struct btrfs_trans_handle *trans,
                return ret;
        }
 
+       /*
+        * Now that our block group has its ->space_info set and is inserted in
+        * the rbtree, update the space info's counters.
+        */
        ret = update_space_info(root->fs_info, cache->flags, size, bytes_used,
                                &cache->space_info);
        if (ret) {