btrfs: qgroup: Cleanup open-coded old/new_refcnt update and read.

Use inline functions to do such things, to improve readability.

Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
Acked-by: David Sterba <dsterba@suse.cz>
Signed-off-by: Chris Mason <clm@fb.com>

diff --git a/fs/btrfs/qgroup.c b/fs/btrfs/qgroup.c
index 842ff86d4ae880fb37398120c552b7eefdd42df1..26f9da26e17e15251d988b34e15dc377de2d0b37 100644 (file)
--- a/fs/btrfs/qgroup.c
+++ b/fs/btrfs/qgroup.c
@@ -84,11 +84,42 @@ struct btrfs_qgroup {
 
        /*
         * temp variables for accounting operations
+        * Refer to qgroup_shared_accouting() for details.
         */
        u64 old_refcnt;
        u64 new_refcnt;
 };
 
+static void btrfs_qgroup_update_old_refcnt(struct btrfs_qgroup *qg, u64 seq,
+                                          int mod)
+{
+       if (qg->old_refcnt < seq)
+               qg->old_refcnt = seq;
+       qg->old_refcnt += mod;
+}
+
+static void btrfs_qgroup_update_new_refcnt(struct btrfs_qgroup *qg, u64 seq,
+                                          int mod)
+{
+       if (qg->new_refcnt < seq)
+               qg->new_refcnt = seq;
+       qg->new_refcnt += mod;
+}
+
+static inline u64 btrfs_qgroup_get_old_refcnt(struct btrfs_qgroup *qg, u64 seq)
+{
+       if (qg->old_refcnt < seq)
+               return 0;
+       return qg->old_refcnt - seq;
+}
+
+static inline u64 btrfs_qgroup_get_new_refcnt(struct btrfs_qgroup *qg, u64 seq)
+{
+       if (qg->new_refcnt < seq)
+               return 0;
+       return qg->new_refcnt - seq;
+}
+
 /*
  * glue structure to represent the relations between qgroups.
  */
@@ -1601,6 +1632,7 @@ static int qgroup_calc_old_refcnt(struct btrfs_fs_info *fs_info,
                ULIST_ITER_INIT(&tmp_uiter);
                while ((tmp_unode = ulist_next(tmp, &tmp_uiter))) {
                        struct btrfs_qgroup_list *glist;
+                       int mod;
 
                        qg = u64_to_ptr(tmp_unode->aux);
                        /*
@@ -1612,20 +1644,15 @@ static int qgroup_calc_old_refcnt(struct btrfs_fs_info *fs_info,
                         * upper level qgroups in order to determine exclusive
                         * counts.
                         *
-                        * For rescan we want to set old_refcnt to seq so our
-                        * exclusive calculations end up correct.
+                        * For rescan none of the extent is recorded before so
+                        * we just don't add old_refcnt.
                         */
                        if (rescan)
-                               qg->old_refcnt = seq;
-                       else if (qg->old_refcnt < seq)
-                               qg->old_refcnt = seq + 1;
-                       else
-                               qg->old_refcnt++;
-
-                       if (qg->new_refcnt < seq)
-                               qg->new_refcnt = seq + 1;
+                               mod = 0;
                        else
-                               qg->new_refcnt++;
+                               mod = 1;
+                       btrfs_qgroup_update_old_refcnt(qg, seq, mod);
+                       btrfs_qgroup_update_new_refcnt(qg, seq, 1);
                        list_for_each_entry(glist, &qg->groups, next_group) {
                                ret = ulist_add(qgroups, glist->group->qgroupid,
                                                ptr_to_u64(glist->group),
@@ -1719,14 +1746,8 @@ next:
                struct btrfs_qgroup_list *glist;
 
                qg = u64_to_ptr(unode->aux);
-               if (qg->old_refcnt < seq)
-                       qg->old_refcnt = seq + 1;
-               else
-                       qg->old_refcnt++;
-               if (qg->new_refcnt < seq)
-                       qg->new_refcnt = seq + 1;
-               else
-                       qg->new_refcnt++;
+               btrfs_qgroup_update_old_refcnt(qg, seq, 1);
+               btrfs_qgroup_update_new_refcnt(qg, seq, 1);
                list_for_each_entry(glist, &qg->groups, next_group) {
                        ret = ulist_add(qgroups, glist->group->qgroupid,
                                        ptr_to_u64(glist->group), GFP_ATOMIC);
@@ -1767,17 +1788,10 @@ static int qgroup_calc_new_refcnt(struct btrfs_fs_info *fs_info,
                struct btrfs_qgroup_list *glist;
 
                qg = u64_to_ptr(unode->aux);
-               if (oper->type == BTRFS_QGROUP_OPER_ADD_SHARED) {
-                       if (qg->new_refcnt < seq)
-                               qg->new_refcnt = seq + 1;
-                       else
-                               qg->new_refcnt++;
-               } else {
-                       if (qg->old_refcnt < seq)
-                               qg->old_refcnt = seq + 1;
-                       else
-                               qg->old_refcnt++;
-               }
+               if (oper->type == BTRFS_QGROUP_OPER_ADD_SHARED)
+                       btrfs_qgroup_update_new_refcnt(qg, seq, 1);
+               else
+                       btrfs_qgroup_update_old_refcnt(qg, seq, 1);
                list_for_each_entry(glist, &qg->groups, next_group) {
                        ret = ulist_add(tmp, glist->group->qgroupid,
                                        ptr_to_u64(glist->group), GFP_ATOMIC);
@@ -1810,11 +1824,14 @@ static int qgroup_adjust_counters(struct btrfs_fs_info *fs_info,
                bool dirty = false;
 
                qg = u64_to_ptr(unode->aux);
+               cur_old_count = btrfs_qgroup_get_old_refcnt(qg, seq);
+               cur_new_count = btrfs_qgroup_get_new_refcnt(qg, seq);
+
                /*
                 * Wasn't referenced before but is now, add to the reference
                 * counters.
                 */
-               if (qg->old_refcnt <= seq && qg->new_refcnt > seq) {
+               if (cur_old_count == 0 && cur_new_count > 0) {
                        qg->rfer += num_bytes;
                        qg->rfer_cmpr += num_bytes;
                        dirty = true;
@@ -1824,21 +1841,12 @@ static int qgroup_adjust_counters(struct btrfs_fs_info *fs_info,
                 * Was referenced before but isn't now, subtract from the
                 * reference counters.
                 */
-               if (qg->old_refcnt > seq && qg->new_refcnt <= seq) {
+               if (cur_old_count > 0 && cur_new_count == 0) {
                        qg->rfer -= num_bytes;
                        qg->rfer_cmpr -= num_bytes;
                        dirty = true;
                }
 
-               if (qg->old_refcnt < seq)
-                       cur_old_count = 0;
-               else
-                       cur_old_count = qg->old_refcnt - seq;
-               if (qg->new_refcnt < seq)
-                       cur_new_count = 0;
-               else
-                       cur_new_count = qg->new_refcnt - seq;
-
                /*
                 * If our refcount was the same as the roots previously but our
                 * new count isn't the same as the number of roots now then we
@@ -2036,6 +2044,11 @@ static int qgroup_shared_accounting(struct btrfs_trans_handle *trans,
                new_roots = old_roots;
                old_roots++;
        }
+
+       /*
+        * Bump qgroup_seq to avoid seq overlap
+        * XXX: This makes qgroup_seq mismatch with oper->seq.
+        */
        fs_info->qgroup_seq += old_roots + 1;