btrfs: qgroup: Fix a race in delayed_ref which leads to abort trans

Between btrfs_allocerved_file_extent() and
btrfs_add_delayed_qgroup_reserve(), there is a window that delayed_refs
are run and delayed ref head maybe freed before
btrfs_add_delayed_qgroup_reserve().

This will cause btrfs_dad_delayed_qgroup_reserve() to return -ENOENT,
and cause transaction to be aborted.

This patch will record qgroup reserve space info into delayed_ref_head
at btrfs_add_delayed_ref(), to eliminate the race window.

Reported-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
Signed-off-by: Chris Mason <clm@fb.com>

1 files changed, 8 insertions, 6 deletions

diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index c1f8c7e27a6d..f50c7c2e2b59 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -2087,8 +2087,8 @@ int btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
                                         BTRFS_ADD_DELAYED_REF, NULL);
         } else {
                 ret = btrfs_add_delayed_data_ref(fs_info, trans, bytenr,
-                                        num_bytes,
-                                        parent, root_objectid, owner, offset,
+                                        num_bytes, parent, root_objectid,
+                                        owner, offset, 0,
                                         BTRFS_ADD_DELAYED_REF, NULL);
         }
         return ret;
@@ -6832,8 +6832,8 @@ int btrfs_free_extent(struct btrfs_trans_handle *trans, struct btrfs_root *root,
                 ret = btrfs_add_delayed_data_ref(fs_info, trans, bytenr,
                                                 num_bytes,
                                                 parent, root_objectid, owner,
-                                                offset, BTRFS_DROP_DELAYED_REF,
-                                                NULL);
+                                                offset, 0,
+                                                BTRFS_DROP_DELAYED_REF, NULL);
         }
         return ret;
 }
@@ -7759,7 +7759,8 @@ static int alloc_reserved_tree_block(struct btrfs_trans_handle *trans,
 int btrfs_alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
                                      struct btrfs_root *root,
                                      u64 root_objectid, u64 owner,
-                                     u64 offset, struct btrfs_key *ins)
+                                     u64 offset, u64 ram_bytes,
+                                     struct btrfs_key *ins)
 {
         int ret;
 
@@ -7768,7 +7769,8 @@ int btrfs_alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
         ret = btrfs_add_delayed_data_ref(root->fs_info, trans, ins->objectid,
                                          ins->offset, 0,
                                          root_objectid, owner, offset,
-                                         BTRFS_ADD_DELAYED_EXTENT, NULL);
+                                         ram_bytes, BTRFS_ADD_DELAYED_EXTENT,
+                                         NULL);
         return ret;
 }