btrfs: qgroup: use qgroup_iterator in __qgroup_excl_accounting()

With the new qgroup_iterator_add() and qgroup_iterator_clean(), we can
get rid of the ulist and its GFP_ATOMIC memory allocation.

Furthermore we can merge the code handling the initial and parent
qgroups into one loop, and drop the @tmp ulist parameter for involved
call sites.

Reviewed-by: Boris Burkov <boris@bur.io>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

diff --git a/fs/btrfs/qgroup.c b/fs/btrfs/qgroup.c
index b2a73437dbad3e4d46045743e6cb63b23f4c8f30..a0bf8e6a8b1f2be16086767585a034c0cf3c0837 100644 (file)
--- a/fs/btrfs/qgroup.c
+++ b/fs/btrfs/qgroup.c
@@ -1375,14 +1375,12 @@ static void qgroup_iterator_clean(struct list_head *head)
  *
  * Caller should hold fs_info->qgroup_lock.
  */
-static int __qgroup_excl_accounting(struct btrfs_fs_info *fs_info,
-                                   struct ulist *tmp, u64 ref_root,
+static int __qgroup_excl_accounting(struct btrfs_fs_info *fs_info, u64 ref_root,
                                    struct btrfs_qgroup *src, int sign)
 {
        struct btrfs_qgroup *qgroup;
-       struct btrfs_qgroup_list *glist;
-       struct ulist_node *unode;
-       struct ulist_iterator uiter;
+       struct btrfs_qgroup *cur;
+       LIST_HEAD(qgroup_list);
        u64 num_bytes = src->excl;
        int ret = 0;
 
@@ -1390,53 +1388,30 @@ static int __qgroup_excl_accounting(struct btrfs_fs_info *fs_info,
        if (!qgroup)
                goto out;
 
-       qgroup->rfer += sign * num_bytes;
-       qgroup->rfer_cmpr += sign * num_bytes;
-
-       WARN_ON(sign < 0 && qgroup->excl < num_bytes);
-       qgroup->excl += sign * num_bytes;
-       qgroup->excl_cmpr += sign * num_bytes;
-
-       if (sign > 0)
-               qgroup_rsv_add_by_qgroup(fs_info, qgroup, src);
-       else
-               qgroup_rsv_release_by_qgroup(fs_info, qgroup, src);
-
-       qgroup_dirty(fs_info, qgroup);
-
-       /* Get all of the parent groups that contain this qgroup */
-       list_for_each_entry(glist, &qgroup->groups, next_group) {
-               ret = ulist_add(tmp, glist->group->qgroupid,
-                               qgroup_to_aux(glist->group), GFP_ATOMIC);
-               if (ret < 0)
-                       goto out;
-       }
+       qgroup_iterator_add(&qgroup_list, qgroup);
+       list_for_each_entry(cur, &qgroup_list, iterator) {
+               struct btrfs_qgroup_list *glist;
 
-       /* Iterate all of the parents and adjust their reference counts */
-       ULIST_ITER_INIT(&uiter);
-       while ((unode = ulist_next(tmp, &uiter))) {
-               qgroup = unode_aux_to_qgroup(unode);
                qgroup->rfer += sign * num_bytes;
                qgroup->rfer_cmpr += sign * num_bytes;
+
                WARN_ON(sign < 0 && qgroup->excl < num_bytes);
                qgroup->excl += sign * num_bytes;
+               qgroup->excl_cmpr += sign * num_bytes;
+
                if (sign > 0)
                        qgroup_rsv_add_by_qgroup(fs_info, qgroup, src);
                else
                        qgroup_rsv_release_by_qgroup(fs_info, qgroup, src);
-               qgroup->excl_cmpr += sign * num_bytes;
                qgroup_dirty(fs_info, qgroup);
 
-               /* Add any parents of the parents */
-               list_for_each_entry(glist, &qgroup->groups, next_group) {
-                       ret = ulist_add(tmp, glist->group->qgroupid,
-                                       qgroup_to_aux(glist->group), GFP_ATOMIC);
-                       if (ret < 0)
-                               goto out;
-               }
+               /* Append parent qgroups to @qgroup_list. */
+               list_for_each_entry(glist, &qgroup->groups, next_group)
+                       qgroup_iterator_add(&qgroup_list, glist->group);
        }
        ret = 0;
 out:
+       qgroup_iterator_clean(&qgroup_list);
        return ret;
 }
 
@@ -1453,8 +1428,7 @@ out:
  * Return < 0 for other error.
  */
 static int quick_update_accounting(struct btrfs_fs_info *fs_info,
-                                  struct ulist *tmp, u64 src, u64 dst,
-                                  int sign)
+                                  u64 src, u64 dst, int sign)
 {
        struct btrfs_qgroup *qgroup;
        int ret = 1;
@@ -1465,8 +1439,7 @@ static int quick_update_accounting(struct btrfs_fs_info *fs_info,
                goto out;
        if (qgroup->excl == qgroup->rfer) {
                ret = 0;
-               err = __qgroup_excl_accounting(fs_info, tmp, dst,
-                                              qgroup, sign);
+               err = __qgroup_excl_accounting(fs_info, dst, qgroup, sign);
                if (err < 0) {
                        ret = err;
                        goto out;
@@ -1485,21 +1458,12 @@ int btrfs_add_qgroup_relation(struct btrfs_trans_handle *trans, u64 src,
        struct btrfs_qgroup *parent;
        struct btrfs_qgroup *member;
        struct btrfs_qgroup_list *list;
-       struct ulist *tmp;
-       unsigned int nofs_flag;
        int ret = 0;
 
        /* Check the level of src and dst first */
        if (btrfs_qgroup_level(src) >= btrfs_qgroup_level(dst))
                return -EINVAL;
 
-       /* We hold a transaction handle open, must do a NOFS allocation. */
-       nofs_flag = memalloc_nofs_save();
-       tmp = ulist_alloc(GFP_KERNEL);
-       memalloc_nofs_restore(nofs_flag);
-       if (!tmp)
-               return -ENOMEM;
-
        mutex_lock(&fs_info->qgroup_ioctl_lock);
        if (!fs_info->quota_root) {
                ret = -ENOTCONN;
@@ -1536,11 +1500,10 @@ int btrfs_add_qgroup_relation(struct btrfs_trans_handle *trans, u64 src,
                spin_unlock(&fs_info->qgroup_lock);
                goto out;
        }
-       ret = quick_update_accounting(fs_info, tmp, src, dst, 1);
+       ret = quick_update_accounting(fs_info, src, dst, 1);
        spin_unlock(&fs_info->qgroup_lock);
 out:
        mutex_unlock(&fs_info->qgroup_ioctl_lock);
-       ulist_free(tmp);
        return ret;
 }
 
@@ -1551,19 +1514,10 @@ static int __del_qgroup_relation(struct btrfs_trans_handle *trans, u64 src,
        struct btrfs_qgroup *parent;
        struct btrfs_qgroup *member;
        struct btrfs_qgroup_list *list;
-       struct ulist *tmp;
        bool found = false;
-       unsigned int nofs_flag;
        int ret = 0;
        int ret2;
 
-       /* We hold a transaction handle open, must do a NOFS allocation. */
-       nofs_flag = memalloc_nofs_save();
-       tmp = ulist_alloc(GFP_KERNEL);
-       memalloc_nofs_restore(nofs_flag);
-       if (!tmp)
-               return -ENOMEM;
-
        if (!fs_info->quota_root) {
                ret = -ENOTCONN;
                goto out;
@@ -1601,11 +1555,10 @@ delete_item:
        if (found) {
                spin_lock(&fs_info->qgroup_lock);
                del_relation_rb(fs_info, src, dst);
-               ret = quick_update_accounting(fs_info, tmp, src, dst, -1);
+               ret = quick_update_accounting(fs_info, src, dst, -1);
                spin_unlock(&fs_info->qgroup_lock);
        }
 out:
-       ulist_free(tmp);
        return ret;
 }