Btrfs: hold the commit_root_sem when getting the commit root during send

[sagit-ice-cold/kernel_xiaomi_msm8998.git] / fs / btrfs / ctree.c

diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c
index 9d89c16..1bcfcdb 100644 (file)
--- a/fs/btrfs/ctree.c
+++ b/fs/btrfs/ctree.c
@@ -2769,9 +2769,13 @@ again:
                 * the commit roots are read only
                 * so we always do read locks
                 */
+               if (p->need_commit_sem)
+                       down_read(&root->fs_info->commit_root_sem);
                b = root->commit_root;
                extent_buffer_get(b);
                level = btrfs_header_level(b);
+               if (p->need_commit_sem)
+                       up_read(&root->fs_info->commit_root_sem);
                if (!p->skip_locking)
                        btrfs_tree_read_lock(b);
        } else {
@@ -5436,6 +5440,7 @@ int btrfs_compare_trees(struct btrfs_root *left_root,
         *   the right if possible or go up and right.
         */
 
+       down_read(&left_root->fs_info->commit_root_sem);
        left_level = btrfs_header_level(left_root->commit_root);
        left_root_level = left_level;
        left_path->nodes[left_level] = left_root->commit_root;
@@ -5445,6 +5450,7 @@ int btrfs_compare_trees(struct btrfs_root *left_root,
        right_root_level = right_level;
        right_path->nodes[right_level] = right_root->commit_root;
        extent_buffer_get(right_path->nodes[right_level]);
+       up_read(&left_root->fs_info->commit_root_sem);
 
        if (left_level == 0)
                btrfs_item_key_to_cpu(left_path->nodes[left_level],