Btrfs: split btrfs_qgroup_account_ref into four functions

The function is separated into a preparation part and the three accounting
steps mentioned in the qgroups documentation. The goal is to make steps two
and three usable by the rescan functionality. A side effect is that the
function is restructured into readable subunits.

Signed-off-by: Jan Schmidt <list.btrfs@jan-o-sch.net>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>

diff --git a/fs/btrfs/qgroup.c b/fs/btrfs/qgroup.c
index e5c5623..1fb7d8d 100644 (file)
--- a/fs/btrfs/qgroup.c
+++ b/fs/btrfs/qgroup.c
@@ -1185,6 +1185,144 @@ int btrfs_qgroup_record_ref(struct btrfs_trans_handle *trans,
        return 0;
 }
 
+static int qgroup_account_ref_step1(struct btrfs_fs_info *fs_info,
+                                   struct ulist *roots, struct ulist *tmp,
+                                   u64 seq)
+{
+       struct ulist_node *unode;
+       struct ulist_iterator uiter;
+       struct ulist_node *tmp_unode;
+       struct ulist_iterator tmp_uiter;
+       struct btrfs_qgroup *qg;
+       int ret;
+
+       ULIST_ITER_INIT(&uiter);
+       while ((unode = ulist_next(roots, &uiter))) {
+               qg = find_qgroup_rb(fs_info, unode->val);
+               if (!qg)
+                       continue;
+
+               ulist_reinit(tmp);
+                                               /* XXX id not needed */
+               ret = ulist_add(tmp, qg->qgroupid,
+                               (u64)(uintptr_t)qg, GFP_ATOMIC);
+               if (ret < 0)
+                       return ret;
+               ULIST_ITER_INIT(&tmp_uiter);
+               while ((tmp_unode = ulist_next(tmp, &tmp_uiter))) {
+                       struct btrfs_qgroup_list *glist;
+
+                       qg = (struct btrfs_qgroup *)(uintptr_t)tmp_unode->aux;
+                       if (qg->refcnt < seq)
+                               qg->refcnt = seq + 1;
+                       else
+                               ++qg->refcnt;
+
+                       list_for_each_entry(glist, &qg->groups, next_group) {
+                               ret = ulist_add(tmp, glist->group->qgroupid,
+                                               (u64)(uintptr_t)glist->group,
+                                               GFP_ATOMIC);
+                               if (ret < 0)
+                                       return ret;
+                       }
+               }
+       }
+
+       return 0;
+}
+
+static int qgroup_account_ref_step2(struct btrfs_fs_info *fs_info,
+                                   struct ulist *roots, struct ulist *tmp,
+                                   u64 seq, int sgn, u64 num_bytes,
+                                   struct btrfs_qgroup *qgroup)
+{
+       struct ulist_node *unode;
+       struct ulist_iterator uiter;
+       struct btrfs_qgroup *qg;
+       struct btrfs_qgroup_list *glist;
+       int ret;
+
+       ulist_reinit(tmp);
+       ret = ulist_add(tmp, qgroup->qgroupid, (uintptr_t)qgroup, GFP_ATOMIC);
+       if (ret < 0)
+               return ret;
+
+       ULIST_ITER_INIT(&uiter);
+       while ((unode = ulist_next(tmp, &uiter))) {
+               qg = (struct btrfs_qgroup *)(uintptr_t)unode->aux;
+               if (qg->refcnt < seq) {
+                       /* not visited by step 1 */
+                       qg->rfer += sgn * num_bytes;
+                       qg->rfer_cmpr += sgn * num_bytes;
+                       if (roots->nnodes == 0) {
+                               qg->excl += sgn * num_bytes;
+                               qg->excl_cmpr += sgn * num_bytes;
+                       }
+                       qgroup_dirty(fs_info, qg);
+               }
+               WARN_ON(qg->tag >= seq);
+               qg->tag = seq;
+
+               list_for_each_entry(glist, &qg->groups, next_group) {
+                       ret = ulist_add(tmp, glist->group->qgroupid,
+                                       (uintptr_t)glist->group, GFP_ATOMIC);
+                       if (ret < 0)
+                               return ret;
+               }
+       }
+
+       return 0;
+}
+
+static int qgroup_account_ref_step3(struct btrfs_fs_info *fs_info,
+                                   struct ulist *roots, struct ulist *tmp,
+                                   u64 seq, int sgn, u64 num_bytes)
+{
+       struct ulist_node *unode;
+       struct ulist_iterator uiter;
+       struct btrfs_qgroup *qg;
+       struct ulist_node *tmp_unode;
+       struct ulist_iterator tmp_uiter;
+       int ret;
+
+       ULIST_ITER_INIT(&uiter);
+       while ((unode = ulist_next(roots, &uiter))) {
+               qg = find_qgroup_rb(fs_info, unode->val);
+               if (!qg)
+                       continue;
+
+               ulist_reinit(tmp);
+               ret = ulist_add(tmp, qg->qgroupid, (uintptr_t)qg, GFP_ATOMIC);
+               if (ret < 0)
+                       return ret;
+
+               ULIST_ITER_INIT(&tmp_uiter);
+               while ((tmp_unode = ulist_next(tmp, &tmp_uiter))) {
+                       struct btrfs_qgroup_list *glist;
+
+                       qg = (struct btrfs_qgroup *)(uintptr_t)tmp_unode->aux;
+                       if (qg->tag == seq)
+                               continue;
+
+                       if (qg->refcnt - seq == roots->nnodes) {
+                               qg->excl -= sgn * num_bytes;
+                               qg->excl_cmpr -= sgn * num_bytes;
+                               qgroup_dirty(fs_info, qg);
+                       }
+
+                       list_for_each_entry(glist, &qg->groups, next_group) {
+                               ret = ulist_add(tmp, glist->group->qgroupid,
+                                               (uintptr_t)glist->group,
+                                               GFP_ATOMIC);
+                               if (ret < 0)
+                                       return ret;
+                       }
+               }
+       }
+
+       return 0;
+}
+
 /*
  * btrfs_qgroup_account_ref is called for every ref that is added to or deleted
  * from the fs. First, all roots referencing the extent are searched, and
@@ -1200,10 +1338,8 @@ int btrfs_qgroup_account_ref(struct btrfs_trans_handle *trans,
        struct btrfs_root *quota_root;
        u64 ref_root;
        struct btrfs_qgroup *qgroup;
-       struct ulist_node *unode;
        struct ulist *roots = NULL;
        struct ulist *tmp = NULL;
-       struct ulist_iterator uiter;
        u64 seq;
        int ret = 0;
        int sgn;
@@ -1287,119 +1423,26 @@ int btrfs_qgroup_account_ref(struct btrfs_trans_handle *trans,
        seq = fs_info->qgroup_seq;
        fs_info->qgroup_seq += roots->nnodes + 1; /* max refcnt */
 
-       ULIST_ITER_INIT(&uiter);
-       while ((unode = ulist_next(roots, &uiter))) {
-               struct ulist_node *tmp_unode;
-               struct ulist_iterator tmp_uiter;
-               struct btrfs_qgroup *qg;
-
-               qg = find_qgroup_rb(fs_info, unode->val);
-               if (!qg)
-                       continue;
-
-               ulist_reinit(tmp);
-                                               /* XXX id not needed */
-               ret = ulist_add(tmp, qg->qgroupid,
-                               (u64)(uintptr_t)qg, GFP_ATOMIC);
-               if (ret < 0)
-                       goto unlock;
-               ULIST_ITER_INIT(&tmp_uiter);
-               while ((tmp_unode = ulist_next(tmp, &tmp_uiter))) {
-                       struct btrfs_qgroup_list *glist;
-
-                       qg = (struct btrfs_qgroup *)(uintptr_t)tmp_unode->aux;
-                       if (qg->refcnt < seq)
-                               qg->refcnt = seq + 1;
-                       else
-                               ++qg->refcnt;
-
-                       list_for_each_entry(glist, &qg->groups, next_group) {
-                               ret = ulist_add(tmp, glist->group->qgroupid,
-                                               (u64)(uintptr_t)glist->group,
-                                               GFP_ATOMIC);
-                               if (ret < 0)
-                                       goto unlock;
-                       }
-               }
-       }
+       ret = qgroup_account_ref_step1(fs_info, roots, tmp, seq);
+       if (ret)
+               goto unlock;
 
        /*
         * step 2: walk from the new root
         */
-       ulist_reinit(tmp);
-       ret = ulist_add(tmp, qgroup->qgroupid,
-                       (uintptr_t)qgroup, GFP_ATOMIC);
-       if (ret < 0)
+       ret = qgroup_account_ref_step2(fs_info, roots, tmp, seq, sgn,
+                                      node->num_bytes, qgroup);
+       if (ret)
                goto unlock;
-       ULIST_ITER_INIT(&uiter);
-       while ((unode = ulist_next(tmp, &uiter))) {
-               struct btrfs_qgroup *qg;
-               struct btrfs_qgroup_list *glist;
-
-               qg = (struct btrfs_qgroup *)(uintptr_t)unode->aux;
-               if (qg->refcnt < seq) {
-                       /* not visited by step 1 */
-                       qg->rfer += sgn * node->num_bytes;
-                       qg->rfer_cmpr += sgn * node->num_bytes;
-                       if (roots->nnodes == 0) {
-                               qg->excl += sgn * node->num_bytes;
-                               qg->excl_cmpr += sgn * node->num_bytes;
-                       }
-                       qgroup_dirty(fs_info, qg);
-               }
-               WARN_ON(qg->tag >= seq);
-               qg->tag = seq;
-
-               list_for_each_entry(glist, &qg->groups, next_group) {
-                       ret = ulist_add(tmp, glist->group->qgroupid,
-                                       (uintptr_t)glist->group, GFP_ATOMIC);
-                       if (ret < 0)
-                               goto unlock;
-               }
-       }
 
        /*
         * step 3: walk again from old refs
         */
-       ULIST_ITER_INIT(&uiter);
-       while ((unode = ulist_next(roots, &uiter))) {
-               struct btrfs_qgroup *qg;
-               struct ulist_node *tmp_unode;
-               struct ulist_iterator tmp_uiter;
-
-               qg = find_qgroup_rb(fs_info, unode->val);
-               if (!qg)
-                       continue;
-
-               ulist_reinit(tmp);
-               ret = ulist_add(tmp, qg->qgroupid,
-                               (uintptr_t)qg, GFP_ATOMIC);
-               if (ret < 0)
-                       goto unlock;
-               ULIST_ITER_INIT(&tmp_uiter);
-               while ((tmp_unode = ulist_next(tmp, &tmp_uiter))) {
-                       struct btrfs_qgroup_list *glist;
-
-                       qg = (struct btrfs_qgroup *)(uintptr_t)tmp_unode->aux;
-                       if (qg->tag == seq)
-                               continue;
-
-                       if (qg->refcnt - seq == roots->nnodes) {
-                               qg->excl -= sgn * node->num_bytes;
-                               qg->excl_cmpr -= sgn * node->num_bytes;
-                               qgroup_dirty(fs_info, qg);
-                       }
+       ret = qgroup_account_ref_step3(fs_info, roots, tmp, seq, sgn,
+                                      node->num_bytes);
+       if (ret)
+               goto unlock;
 
-                       list_for_each_entry(glist, &qg->groups, next_group) {
-                               ret = ulist_add(tmp, glist->group->qgroupid,
-                                               (uintptr_t)glist->group,
-                                               GFP_ATOMIC);
-                               if (ret < 0)
-                                       goto unlock;
-                       }
-               }
-       }
-       ret = 0;
 unlock:
        spin_unlock(&fs_info->qgroup_lock);
        ulist_free(roots);