3 files changed, 24 insertions, 13 deletions

diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index f9f512be9d41..df0463e2ab7f 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -1264,9 +1264,6 @@ struct btrfs_root {
         int send_in_progress;
         struct btrfs_subvolume_writers *subv_writers;
         atomic_t will_be_snapshotted;
-
-        /* For qgroup metadata space reserve */
-        atomic64_t qgroup_meta_rsv;
 };
 
 struct btrfs_file_private {
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 38b387ae78f8..ad900f821f1e 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -1163,7 +1163,6 @@ static void __setup_root(struct btrfs_root *root, struct btrfs_fs_info *fs_info,
         atomic_set(&root->orphan_inodes, 0);
         refcount_set(&root->refs, 1);
         atomic_set(&root->will_be_snapshotted, 0);
-        atomic64_set(&root->qgroup_meta_rsv, 0);
         root->log_transid = 0;
         root->log_transid_committed = -1;
         root->last_log_commit = 0;
diff --git a/fs/btrfs/qgroup.c b/fs/btrfs/qgroup.c
index 8831eaa14204..a7ca464cdbf7 100644
--- a/fs/btrfs/qgroup.c
+++ b/fs/btrfs/qgroup.c
@@ -2499,6 +2499,15 @@ out:
         return ret;
 }
 
+/*
+ * Free @num_bytes of reserved space with @type for qgroup.  (Normally level 0
+ * qgroup).
+ *
+ * Will handle all higher level qgroup too.
+ *
+ * NOTE: If @num_bytes is (u64)-1, this means to free all bytes of this qgroup.
+ * This special case is only used for META_PERTRANS type.
+ */
 void btrfs_qgroup_free_refroot(struct btrfs_fs_info *fs_info,
                                u64 ref_root, u64 num_bytes,
                                enum btrfs_qgroup_rsv_type type)
@@ -2515,6 +2524,10 @@ void btrfs_qgroup_free_refroot(struct btrfs_fs_info *fs_info,
         if (num_bytes == 0)
                 return;
 
+        if (num_bytes == (u64)-1 && type != BTRFS_QGROUP_RSV_META_PERTRANS) {
+                WARN(1, "%s: Invalid type to free", __func__);
+                return;
+        }
         spin_lock(&fs_info->qgroup_lock);
 
         quota_root = fs_info->quota_root;
@@ -2525,6 +2538,13 @@ void btrfs_qgroup_free_refroot(struct btrfs_fs_info *fs_info,
         if (!qgroup)
                 goto out;
 
+        /*
+         * We're freeing all pertrans rsv, get current value from level 0
+         * qgroup as real num_bytes to free.
+         */
+        if (num_bytes == (u64)-1)
+                num_bytes = qgroup->rsv.values[type];
+
         ulist_reinit(fs_info->qgroup_ulist);
         ret = ulist_add(fs_info->qgroup_ulist, qgroup->qgroupid,
                         (uintptr_t)qgroup, GFP_ATOMIC);
@@ -3082,24 +3102,21 @@ int __btrfs_qgroup_reserve_meta(struct btrfs_root *root, int num_bytes,
         ret = qgroup_reserve(root, num_bytes, enforce, type);
         if (ret < 0)
                 return ret;
-        atomic64_add(num_bytes, &root->qgroup_meta_rsv);
         return ret;
 }
 
 void btrfs_qgroup_free_meta_all_pertrans(struct btrfs_root *root)
 {
         struct btrfs_fs_info *fs_info = root->fs_info;
-        u64 reserved;
 
         if (!test_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags) ||
             !is_fstree(root->objectid))
                 return;
 
-        reserved = atomic64_xchg(&root->qgroup_meta_rsv, 0);
-        if (reserved == 0)
-                return;
-        trace_qgroup_meta_reserve(root, -(s64)reserved);
-        btrfs_qgroup_free_refroot(fs_info, root->objectid, reserved,
+        /* TODO: Update trace point to handle such free */
+        trace_qgroup_meta_reserve(root, 0);
+        /* Special value -1 means to free all reserved space */
+        btrfs_qgroup_free_refroot(fs_info, root->objectid, (u64)-1,
                                   BTRFS_QGROUP_RSV_META_PERTRANS);
 }
 
@@ -3113,8 +3130,6 @@ void __btrfs_qgroup_free_meta(struct btrfs_root *root, int num_bytes,
                 return;
 
         BUG_ON(num_bytes != round_down(num_bytes, fs_info->nodesize));
-        WARN_ON(atomic64_read(&root->qgroup_meta_rsv) < num_bytes);
-        atomic64_sub(num_bytes, &root->qgroup_meta_rsv);
         trace_qgroup_meta_reserve(root, -(s64)num_bytes);
         btrfs_qgroup_free_refroot(fs_info, root->objectid, num_bytes, type);
 }