btrfs: qgroup: Add the ability to skip given qgroup for old/new_roots.

This is used by later qgroup fix patches for snapshot.

As current snapshot accounting is done by btrfs_qgroup_inherit(), but
new extent oriented quota mechanism will account extent from
btrfs_copy_root() and other snapshot things, causing wrong result.

So add this ability to handle snapshot accounting.

Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
Signed-off-by: Chris Mason <clm@fb.com>

4 files changed, 40 insertions, 0 deletions

diff --git a/fs/btrfs/delayed-ref.h b/fs/btrfs/delayed-ref.h
index 4016f963599e..13fb5e6090fe 100644
--- a/fs/btrfs/delayed-ref.h
+++ b/fs/btrfs/delayed-ref.h
@@ -175,6 +175,14 @@ struct btrfs_delayed_ref_root {
         int flushing;
 
         u64 run_delayed_start;
+
+        /*
+         * To make qgroup to skip given root.
+         * This is for snapshot, as btrfs_qgroup_inherit() will manully
+         * modify counters for snapshot and its source, so we should skip
+         * the snapshot in new_root/old_roots or it will get calculated twice
+         */
+        u64 qgroup_to_skip;
 };
 
 extern struct kmem_cache *btrfs_delayed_ref_head_cachep;
diff --git a/fs/btrfs/qgroup.c b/fs/btrfs/qgroup.c
index c5aa0d34940e..d5f1f033b7a0 100644
--- a/fs/btrfs/qgroup.c
+++ b/fs/btrfs/qgroup.c
@@ -1394,9 +1394,11 @@ int btrfs_qgroup_prepare_account_extents(struct btrfs_trans_handle *trans,
         struct btrfs_qgroup_extent_record *record;
         struct btrfs_delayed_ref_root *delayed_refs;
         struct rb_node *node;
+        u64 qgroup_to_skip;
         int ret = 0;
 
         delayed_refs = &trans->transaction->delayed_refs;
+        qgroup_to_skip = delayed_refs->qgroup_to_skip;
 
         /*
          * No need to do lock, since this function will only be called in
@@ -1410,6 +1412,8 @@ int btrfs_qgroup_prepare_account_extents(struct btrfs_trans_handle *trans,
                                            &record->old_roots);
                 if (ret < 0)
                         break;
+                if (qgroup_to_skip)
+                        ulist_del(record->old_roots, qgroup_to_skip, 0);
                 node = rb_next(node);
         }
         return ret;
@@ -1702,9 +1706,11 @@ int btrfs_qgroup_account_extents(struct btrfs_trans_handle *trans,
         struct btrfs_delayed_ref_root *delayed_refs;
         struct ulist *new_roots = NULL;
         struct rb_node *node;
+        u64 qgroup_to_skip;
         int ret = 0;
 
         delayed_refs = &trans->transaction->delayed_refs;
+        qgroup_to_skip = delayed_refs->qgroup_to_skip;
         while ((node = rb_first(&delayed_refs->dirty_extent_root))) {
                 record = rb_entry(node, struct btrfs_qgroup_extent_record,
                                   node);
@@ -1719,6 +1725,8 @@ int btrfs_qgroup_account_extents(struct btrfs_trans_handle *trans,
                                         record->bytenr, (u64)-1, &new_roots);
                         if (ret < 0)
                                 goto cleanup;
+                        if (qgroup_to_skip)
+                                ulist_del(new_roots, qgroup_to_skip, 0);
                         ret = btrfs_qgroup_account_extent(trans, fs_info,
                                         record->bytenr, record->num_bytes,
                                         record->old_roots, new_roots);
diff --git a/fs/btrfs/transaction.c b/fs/btrfs/transaction.c
index 6f49715cc127..3e3793dcb4c2 100644
--- a/fs/btrfs/transaction.c
+++ b/fs/btrfs/transaction.c
@@ -232,6 +232,7 @@ loop:
         cur_trans->delayed_refs.num_heads = 0;
         cur_trans->delayed_refs.flushing = 0;
         cur_trans->delayed_refs.run_delayed_start = 0;
+        cur_trans->delayed_refs.qgroup_to_skip = 0;
 
         /*
          * although the tree mod log is per file system and not per transaction,
diff --git a/fs/btrfs/transaction.h b/fs/btrfs/transaction.h
index 036fa83d6ccb..eb09c2067fa8 100644
--- a/fs/btrfs/transaction.h
+++ b/fs/btrfs/transaction.h
@@ -154,6 +154,29 @@ static inline void btrfs_set_inode_last_trans(struct btrfs_trans_handle *trans,
         spin_unlock(&BTRFS_I(inode)->lock);
 }
 
+/*
+ * Make qgroup codes to skip given qgroupid, means the old/new_roots for
+ * qgroup won't contain the qgroupid in it.
+ */
+static inline void btrfs_set_skip_qgroup(struct btrfs_trans_handle *trans,
+                                         u64 qgroupid)
+{
+        struct btrfs_delayed_ref_root *delayed_refs;
+
+        delayed_refs = &trans->transaction->delayed_refs;
+        WARN_ON(delayed_refs->qgroup_to_skip);
+        delayed_refs->qgroup_to_skip = qgroupid;
+}
+
+static inline void btrfs_clear_skip_qgroup(struct btrfs_trans_handle *trans)
+{
+        struct btrfs_delayed_ref_root *delayed_refs;
+
+        delayed_refs = &trans->transaction->delayed_refs;
+        WARN_ON(!delayed_refs->qgroup_to_skip);
+        delayed_refs->qgroup_to_skip = 0;
+}
+
 int btrfs_end_transaction(struct btrfs_trans_handle *trans,
                           struct btrfs_root *root);
 struct btrfs_trans_handle *btrfs_start_transaction(struct btrfs_root *root,