btrfs: qgroup: Cleanup the old ref_node-oriented mechanism.

Goodbye, the old mechanisim.

Signed-off-by: Qu Wenruo <[e-mail]>
Signed-off-by: Chris Mason <[e-mail]>

fs/btrfs/ctree.h

···
 	/* list of dirty qgroups to be written at next commit */
 	struct list_head dirty_qgroups;
 
-	/* used by btrfs_qgroup_record_ref for an efficient tree traversal */
+	/* used by qgroup for an efficient tree traversal */
 	u64 qgroup_seq;
 
 	/* qgroup rescan items */

fs/btrfs/extent-tree.c

···
 	u64 refs;
 	int ret;
 	int no_quota = node->no_quota;
-	enum btrfs_qgroup_operation_type type = BTRFS_QGROUP_OPER_ADD_EXCL;
 
 	path = btrfs_alloc_path();
 	if (!path)
···
 	btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
 	item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
 	refs = btrfs_extent_refs(leaf, item);
-	if (refs)
-		type = BTRFS_QGROUP_OPER_ADD_SHARED;
 	btrfs_set_extent_refs(leaf, item, refs + refs_to_add);
 	if (extent_op)
 		__run_delayed_extent_op(extent_op, leaf, item);
···
 	u64 bytenr = node->bytenr;
 	u64 num_bytes = node->num_bytes;
 	int last_ref = 0;
-	enum btrfs_qgroup_operation_type type = BTRFS_QGROUP_OPER_SUB_EXCL;
 	bool skinny_metadata = btrfs_fs_incompat(root->fs_info,
 						 SKINNY_METADATA);
 
···
 	refs -= refs_to_drop;
 
 	if (refs > 0) {
-		type = BTRFS_QGROUP_OPER_SUB_SHARED;
 		if (extent_op)
 			__run_delayed_extent_op(extent_op, leaf, ei);
 		/*

fs/btrfs/qgroup.c

···
 #include "extent_io.h"
 #include "qgroup.h"
 
+
 /* TODO XXX FIXME
  *  - subvol delete -> delete when ref goes to 0? delete limits also?
  *  - reorganize keys
···
 	return ret;
 }
 
-static int comp_oper_exist(struct btrfs_qgroup_operation *oper1,
-			   struct btrfs_qgroup_operation *oper2)
-{
-	/*
-	 * Ignore seq and type here, we're looking for any operation
-	 * at all related to this extent on that root.
-	 */
-	if (oper1->bytenr < oper2->bytenr)
-		return -1;
-	if (oper1->bytenr > oper2->bytenr)
-		return 1;
-	if (oper1->ref_root < oper2->ref_root)
-		return -1;
-	if (oper1->ref_root > oper2->ref_root)
-		return 1;
-	return 0;
-}
-
-static int qgroup_oper_exists(struct btrfs_fs_info *fs_info,
-			      struct btrfs_qgroup_operation *oper)
-{
-	struct rb_node *n;
-	struct btrfs_qgroup_operation *cur;
-	int cmp;
-
-	spin_lock(&fs_info->qgroup_op_lock);
-	n = fs_info->qgroup_op_tree.rb_node;
-	while (n) {
-		cur = rb_entry(n, struct btrfs_qgroup_operation, n);
-		cmp = comp_oper_exist(cur, oper);
-		if (cmp < 0) {
-			n = n->rb_right;
-		} else if (cmp) {
-			n = n->rb_left;
-		} else {
-			spin_unlock(&fs_info->qgroup_op_lock);
-			return -EEXIST;
-		}
-	}
-	spin_unlock(&fs_info->qgroup_op_lock);
-	return 0;
-}
-
-static int comp_oper(struct btrfs_qgroup_operation *oper1,
-		     struct btrfs_qgroup_operation *oper2)
-{
-	if (oper1->bytenr < oper2->bytenr)
-		return -1;
-	if (oper1->bytenr > oper2->bytenr)
-		return 1;
-	if (oper1->ref_root < oper2->ref_root)
-		return -1;
-	if (oper1->ref_root > oper2->ref_root)
-		return 1;
-	if (oper1->seq < oper2->seq)
-		return -1;
-	if (oper1->seq > oper2->seq)
-		return 1;
-	if (oper1->type < oper2->type)
-		return -1;
-	if (oper1->type > oper2->type)
-		return 1;
-	return 0;
-}
-
-static int insert_qgroup_oper(struct btrfs_fs_info *fs_info,
-			      struct btrfs_qgroup_operation *oper)
-{
-	struct rb_node **p;
-	struct rb_node *parent = NULL;
-	struct btrfs_qgroup_operation *cur;
-	int cmp;
-
-	spin_lock(&fs_info->qgroup_op_lock);
-	p = &fs_info->qgroup_op_tree.rb_node;
-	while (*p) {
-		parent = *p;
-		cur = rb_entry(parent, struct btrfs_qgroup_operation, n);
-		cmp = comp_oper(cur, oper);
-		if (cmp < 0) {
-			p = &(*p)->rb_right;
-		} else if (cmp) {
-			p = &(*p)->rb_left;
-		} else {
-			spin_unlock(&fs_info->qgroup_op_lock);
-			return -EEXIST;
-		}
-	}
-	rb_link_node(&oper->n, parent, p);
-	rb_insert_color(&oper->n, &fs_info->qgroup_op_tree);
-	spin_unlock(&fs_info->qgroup_op_lock);
-	return 0;
-}
-
-/*
- * Record a quota operation for processing later on.
- * @trans: the transaction we are adding the delayed op to.
- * @fs_info: the fs_info for this fs.
- * @ref_root: the root of the reference we are acting on,
- * @bytenr: the bytenr we are acting on.
- * @num_bytes: the number of bytes in the reference.
- * @type: the type of operation this is.
- * @mod_seq: do we need to get a sequence number for looking up roots.
- *
- * We just add it to our trans qgroup_ref_list and carry on and process these
- * operations in order at some later point.  If the reference root isn't a fs
- * root then we don't bother with doing anything.
- *
- * MUST BE HOLDING THE REF LOCK.
- */
-int btrfs_qgroup_record_ref(struct btrfs_trans_handle *trans,
-			    struct btrfs_fs_info *fs_info, u64 ref_root,
-			    u64 bytenr, u64 num_bytes,
-			    enum btrfs_qgroup_operation_type type, int mod_seq)
-{
-	struct btrfs_qgroup_operation *oper;
-	int ret;
-
-	if (!is_fstree(ref_root) || !fs_info->quota_enabled)
-		return 0;
-
-	oper = kmalloc(sizeof(*oper), GFP_NOFS);
-	if (!oper)
-		return -ENOMEM;
-
-	oper->ref_root = ref_root;
-	oper->bytenr = bytenr;
-	oper->num_bytes = num_bytes;
-	oper->type = type;
-	oper->seq = atomic_inc_return(&fs_info->qgroup_op_seq);
-	INIT_LIST_HEAD(&oper->elem.list);
-	oper->elem.seq = 0;
-
-	trace_btrfs_qgroup_record_ref(oper);
-
-	if (type == BTRFS_QGROUP_OPER_SUB_SUBTREE) {
-		/*
-		 * If any operation for this bytenr/ref_root combo
-		 * exists, then we know it's not exclusively owned and
-		 * shouldn't be queued up.
-		 *
-		 * This also catches the case where we have a cloned
-		 * extent that gets queued up multiple times during
-		 * drop snapshot.
-		 */
-		if (qgroup_oper_exists(fs_info, oper)) {
-			kfree(oper);
-			return 0;
-		}
-	}
-
-	ret = insert_qgroup_oper(fs_info, oper);
-	if (ret) {
-		/* Shouldn't happen so have an assert for developers */
-		ASSERT(0);
-		kfree(oper);
-		return ret;
-	}
-	list_add_tail(&oper->list, &trans->qgroup_ref_list);
-
-	if (mod_seq)
-		btrfs_get_tree_mod_seq(fs_info, &oper->elem);
-
-	return 0;
-}
-
 int btrfs_qgroup_prepare_account_extents(struct btrfs_trans_handle *trans,
 					 struct btrfs_fs_info *fs_info)
 {
···
 	rb_link_node(&record->node, parent_node, p);
 	rb_insert_color(&record->node, &delayed_refs->dirty_extent_root);
 	return NULL;
-}
-
-/*
- * The easy accounting, if we are adding/removing the only ref for an extent
- * then this qgroup and all of the parent qgroups get their refrence and
- * exclusive counts adjusted.
- */
-static int qgroup_excl_accounting(struct btrfs_fs_info *fs_info,
-				  struct btrfs_qgroup_operation *oper)
-{
-	struct ulist *tmp;
-	int sign = 0;
-	int ret = 0;
-
-	tmp = ulist_alloc(GFP_NOFS);
-	if (!tmp)
-		return -ENOMEM;
-
-	spin_lock(&fs_info->qgroup_lock);
-	if (!fs_info->quota_root)
-		goto out;
-
-	switch (oper->type) {
-	case BTRFS_QGROUP_OPER_ADD_EXCL:
-		sign = 1;
-		break;
-	case BTRFS_QGROUP_OPER_SUB_EXCL:
-		sign = -1;
-		break;
-	default:
-		ASSERT(0);
-	}
-	ret = __qgroup_excl_accounting(fs_info, tmp, oper->ref_root,
-				       oper->num_bytes, sign);
-out:
-	spin_unlock(&fs_info->qgroup_lock);
-	ulist_free(tmp);
-	return ret;
-}
-
-/*
- * Walk all of the roots that pointed to our bytenr and adjust their refcnts as
- * properly.
- */
-static int qgroup_calc_old_refcnt(struct btrfs_fs_info *fs_info,
-				  u64 root_to_skip, struct ulist *tmp,
-				  struct ulist *roots, struct ulist *qgroups,
-				  u64 seq, int *old_roots, int rescan)
-{
-	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))) {
-		/* We don't count our current root here */
-		if (unode->val == root_to_skip)
-			continue;
-		qg = find_qgroup_rb(fs_info, unode->val);
-		if (!qg)
-			continue;
-		/*
-		 * We could have a pending removal of this same ref so we may
-		 * not have actually found our ref root when doing
-		 * btrfs_find_all_roots, so we need to keep track of how many
-		 * old roots we find in case we removed ours and added a
-		 * different one at the same time.  I don't think this could
-		 * happen in practice but that sort of thinking leads to pain
-		 * and suffering and to the dark side.
-		 */
-		(*old_roots)++;
-
-		ulist_reinit(tmp);
-		ret = ulist_add(qgroups, qg->qgroupid, ptr_to_u64(qg),
-				GFP_ATOMIC);
-		if (ret < 0)
-			return ret;
-		ret = ulist_add(tmp, qg->qgroupid, ptr_to_u64(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;
-			int mod;
-
-			qg = u64_to_ptr(tmp_unode->aux);
-			/*
-			 * We use this sequence number to keep from having to
-			 * run the whole list and 0 out the refcnt every time.
-			 * We basically use sequnce as the known 0 count and
-			 * then add 1 everytime we see a qgroup.  This is how we
-			 * get how many of the roots actually point up to the
-			 * upper level qgroups in order to determine exclusive
-			 * counts.
-			 *
-			 * For rescan none of the extent is recorded before so
-			 * we just don't add old_refcnt.
-			 */
-			if (rescan)
-				mod = 0;
-			else
-				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),
-						GFP_ATOMIC);
-				if (ret < 0)
-					return ret;
-				ret = ulist_add(tmp, glist->group->qgroupid,
-						ptr_to_u64(glist->group),
-						GFP_ATOMIC);
-				if (ret < 0)
-					return ret;
-			}
-		}
-	}
-	return 0;
-}
-
-/*
- * We need to walk forward in our operation tree and account for any roots that
- * were deleted after we made this operation.
- */
-static int qgroup_account_deleted_refs(struct btrfs_fs_info *fs_info,
-				       struct btrfs_qgroup_operation *oper,
-				       struct ulist *tmp,
-				       struct ulist *qgroups, u64 seq,
-				       int *old_roots)
-{
-	struct ulist_node *unode;
-	struct ulist_iterator uiter;
-	struct btrfs_qgroup *qg;
-	struct btrfs_qgroup_operation *tmp_oper;
-	struct rb_node *n;
-	int ret;
-
-	ulist_reinit(tmp);
-
-	/*
-	 * We only walk forward in the tree since we're only interested in
-	 * removals that happened _after_  our operation.
-	 */
-	spin_lock(&fs_info->qgroup_op_lock);
-	n = rb_next(&oper->n);
-	spin_unlock(&fs_info->qgroup_op_lock);
-	if (!n)
-		return 0;
-	tmp_oper = rb_entry(n, struct btrfs_qgroup_operation, n);
-	while (tmp_oper->bytenr == oper->bytenr) {
-		/*
-		 * If it's not a removal we don't care, additions work out
-		 * properly with our refcnt tracking.
-		 */
-		if (tmp_oper->type != BTRFS_QGROUP_OPER_SUB_SHARED &&
-		    tmp_oper->type != BTRFS_QGROUP_OPER_SUB_EXCL)
-			goto next;
-		qg = find_qgroup_rb(fs_info, tmp_oper->ref_root);
-		if (!qg)
-			goto next;
-		ret = ulist_add(qgroups, qg->qgroupid, ptr_to_u64(qg),
-				GFP_ATOMIC);
-		if (ret) {
-			if (ret < 0)
-				return ret;
-			/*
-			 * We only want to increase old_roots if this qgroup is
-			 * not already in the list of qgroups.  If it is already
-			 * there then that means it must have been re-added or
-			 * the delete will be discarded because we had an
-			 * existing ref that we haven't looked up yet.  In this
-			 * case we don't want to increase old_roots.  So if ret
-			 * == 1 then we know that this is the first time we've
-			 * seen this qgroup and we can bump the old_roots.
-			 */
-			(*old_roots)++;
-			ret = ulist_add(tmp, qg->qgroupid, ptr_to_u64(qg),
-					GFP_ATOMIC);
-			if (ret < 0)
-				return ret;
-		}
-next:
-		spin_lock(&fs_info->qgroup_op_lock);
-		n = rb_next(&tmp_oper->n);
-		spin_unlock(&fs_info->qgroup_op_lock);
-		if (!n)
-			break;
-		tmp_oper = rb_entry(n, struct btrfs_qgroup_operation, n);
-	}
-
-	/* Ok now process the qgroups we found */
-	ULIST_ITER_INIT(&uiter);
-	while ((unode = ulist_next(tmp, &uiter))) {
-		struct btrfs_qgroup_list *glist;
-
-		qg = u64_to_ptr(unode->aux);
-		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);
-			if (ret < 0)
-				return ret;
-			ret = ulist_add(tmp, glist->group->qgroupid,
-					ptr_to_u64(glist->group), GFP_ATOMIC);
-			if (ret < 0)
-				return ret;
-		}
-	}
-	return 0;
-}
-
-/* Add refcnt for the newly added reference. */
-static int qgroup_calc_new_refcnt(struct btrfs_fs_info *fs_info,
-				  struct btrfs_qgroup_operation *oper,
-				  struct btrfs_qgroup *qgroup,
-				  struct ulist *tmp, struct ulist *qgroups,
-				  u64 seq)
-{
-	struct ulist_node *unode;
-	struct ulist_iterator uiter;
-	struct btrfs_qgroup *qg;
-	int ret;
-
-	ulist_reinit(tmp);
-	ret = ulist_add(qgroups, qgroup->qgroupid, ptr_to_u64(qgroup),
-			GFP_ATOMIC);
-	if (ret < 0)
-		return ret;
-	ret = ulist_add(tmp, qgroup->qgroupid, ptr_to_u64(qgroup),
-			GFP_ATOMIC);
-	if (ret < 0)
-		return ret;
-	ULIST_ITER_INIT(&uiter);
-	while ((unode = ulist_next(tmp, &uiter))) {
-		struct btrfs_qgroup_list *glist;
-
-		qg = u64_to_ptr(unode->aux);
-		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);
-			if (ret < 0)
-				return ret;
-			ret = ulist_add(qgroups, glist->group->qgroupid,
-					ptr_to_u64(glist->group), GFP_ATOMIC);
-			if (ret < 0)
-				return ret;
-		}
-	}
-	return 0;
 }
 
 #define UPDATE_NEW	0
···
 /*
  * Update qgroup rfer/excl counters.
  * Rfer update is easy, codes can explain themselves.
+ *
  * Excl update is tricky, the update is split into 2 part.
  * Part 1: Possible exclusive <-> sharing detect:
  *	|	A	|	!A	|
···
 	return 0;
 }
 
-/*
- * This adjusts the counters for all referenced qgroups if need be.
- */
-static int qgroup_adjust_counters(struct btrfs_fs_info *fs_info,
-				  u64 root_to_skip, u64 num_bytes,
-				  struct ulist *qgroups, u64 seq,
-				  int old_roots, int new_roots, int rescan)
-{
-	struct ulist_node *unode;
-	struct ulist_iterator uiter;
-	struct btrfs_qgroup *qg;
-	u64 cur_new_count, cur_old_count;
-
-	ULIST_ITER_INIT(&uiter);
-	while ((unode = ulist_next(qgroups, &uiter))) {
-		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 (cur_old_count == 0 && cur_new_count > 0) {
-			qg->rfer += num_bytes;
-			qg->rfer_cmpr += num_bytes;
-			dirty = true;
-		}
-
-		/*
-		 * Was referenced before but isn't now, subtract from the
-		 * reference counters.
-		 */
-		if (cur_old_count > 0 && cur_new_count == 0) {
-			qg->rfer -= num_bytes;
-			qg->rfer_cmpr -= num_bytes;
-			dirty = true;
-		}
-
-		/*
-		 * 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
-		 * went from having a exclusive reference on this range to not.
-		 */
-		if (old_roots && cur_old_count == old_roots &&
-		    (cur_new_count != new_roots || new_roots == 0)) {
-			WARN_ON(cur_new_count != new_roots && new_roots == 0);
-			qg->excl -= num_bytes;
-			qg->excl_cmpr -= num_bytes;
-			dirty = true;
-		}
-
-		/*
-		 * If we didn't reference all the roots before but now we do we
-		 * have an exclusive reference to this range.
-		 */
-		if ((!old_roots || (old_roots && cur_old_count != old_roots))
-		    && cur_new_count == new_roots) {
-			qg->excl += num_bytes;
-			qg->excl_cmpr += num_bytes;
-			dirty = true;
-		}
-
-		if (dirty)
-			qgroup_dirty(fs_info, qg);
-	}
-	return 0;
-}
-
-/*
- * If we removed a data extent and there were other references for that bytenr
- * then we need to lookup all referenced roots to make sure we still don't
- * reference this bytenr.  If we do then we can just discard this operation.
- */
-static int check_existing_refs(struct btrfs_trans_handle *trans,
-			       struct btrfs_fs_info *fs_info,
-			       struct btrfs_qgroup_operation *oper)
-{
-	struct ulist *roots = NULL;
-	struct ulist_node *unode;
-	struct ulist_iterator uiter;
-	int ret = 0;
-
-	ret = btrfs_find_all_roots(trans, fs_info, oper->bytenr,
-				   oper->elem.seq, &roots);
-	if (ret < 0)
-		return ret;
-	ret = 0;
-
-	ULIST_ITER_INIT(&uiter);
-	while ((unode = ulist_next(roots, &uiter))) {
-		if (unode->val == oper->ref_root) {
-			ret = 1;
-			break;
-		}
-	}
-	ulist_free(roots);
-	btrfs_put_tree_mod_seq(fs_info, &oper->elem);
-
-	return ret;
-}
-
-/*
- * If we share a reference across multiple roots then we may need to adjust
- * various qgroups referenced and exclusive counters.  The basic premise is this
- *
- * 1) We have seq to represent a 0 count.  Instead of looping through all of the
- * qgroups and resetting their refcount to 0 we just constantly bump this
- * sequence number to act as the base reference count.  This means that if
- * anybody is equal to or below this sequence they were never referenced.  We
- * jack this sequence up by the number of roots we found each time in order to
- * make sure we don't have any overlap.
- *
- * 2) We first search all the roots that reference the area _except_ the root
- * we're acting on currently.  This makes up the old_refcnt of all the qgroups
- * before.
- *
- * 3) We walk all of the qgroups referenced by the root we are currently acting
- * on, and will either adjust old_refcnt in the case of a removal or the
- * new_refcnt in the case of an addition.
- *
- * 4) Finally we walk all the qgroups that are referenced by this range
- * including the root we are acting on currently.  We will adjust the counters
- * based on the number of roots we had and will have after this operation.
- *
- * Take this example as an illustration
- *
- *			[qgroup 1/0]
- *		     /         |          \
- *		[qg 0/0]   [qg 0/1]	[qg 0/2]
- *		   \          |            /
- *		  [	   extent	    ]
- *
- * Say we are adding a reference that is covered by qg 0/0.  The first step
- * would give a refcnt of 1 to qg 0/1 and 0/2 and a refcnt of 2 to qg 1/0 with
- * old_roots being 2.  Because it is adding new_roots will be 1.  We then go
- * through qg 0/0 which will get the new_refcnt set to 1 and add 1 to qg 1/0's
- * new_refcnt, bringing it to 3.  We then walk through all of the qgroups, we
- * notice that the old refcnt for qg 0/0 < the new refcnt, so we added a
- * reference and thus must add the size to the referenced bytes.  Everything
- * else is the same so nothing else changes.
- */
-static int qgroup_shared_accounting(struct btrfs_trans_handle *trans,
-				    struct btrfs_fs_info *fs_info,
-				    struct btrfs_qgroup_operation *oper)
-{
-	struct ulist *roots = NULL;
-	struct ulist *qgroups, *tmp;
-	struct btrfs_qgroup *qgroup;
-	struct seq_list elem = SEQ_LIST_INIT(elem);
-	u64 seq;
-	int old_roots = 0;
-	int new_roots = 0;
-	int ret = 0;
-
-	if (oper->elem.seq) {
-		ret = check_existing_refs(trans, fs_info, oper);
-		if (ret < 0)
-			return ret;
-		if (ret)
-			return 0;
-	}
-
-	qgroups = ulist_alloc(GFP_NOFS);
-	if (!qgroups)
-		return -ENOMEM;
-
-	tmp = ulist_alloc(GFP_NOFS);
-	if (!tmp) {
-		ulist_free(qgroups);
-		return -ENOMEM;
-	}
-
-	btrfs_get_tree_mod_seq(fs_info, &elem);
-	ret = btrfs_find_all_roots(trans, fs_info, oper->bytenr, elem.seq,
-				   &roots);
-	btrfs_put_tree_mod_seq(fs_info, &elem);
-	if (ret < 0) {
-		ulist_free(qgroups);
-		ulist_free(tmp);
-		return ret;
-	}
-	spin_lock(&fs_info->qgroup_lock);
-	qgroup = find_qgroup_rb(fs_info, oper->ref_root);
-	if (!qgroup)
-		goto out;
-	seq = fs_info->qgroup_seq;
-
-	/*
-	 * So roots is the list of all the roots currently pointing at the
-	 * bytenr, including the ref we are adding if we are adding, or not if
-	 * we are removing a ref.  So we pass in the ref_root to skip that root
-	 * in our calculations.  We set old_refnct and new_refcnt cause who the
-	 * hell knows what everything looked like before, and it doesn't matter
-	 * except...
-	 */
-	ret = qgroup_calc_old_refcnt(fs_info, oper->ref_root, tmp, roots, qgroups,
-				     seq, &old_roots, 0);
-	if (ret < 0)
-		goto out;
-
-	/*
-	 * Now adjust the refcounts of the qgroups that care about this
-	 * reference, either the old_count in the case of removal or new_count
-	 * in the case of an addition.
-	 */
-	ret = qgroup_calc_new_refcnt(fs_info, oper, qgroup, tmp, qgroups,
-				     seq);
-	if (ret < 0)
-		goto out;
-
-	/*
-	 * ...in the case of removals.  If we had a removal before we got around
-	 * to processing this operation then we need to find that guy and count
-	 * his references as if they really existed so we don't end up screwing
-	 * up the exclusive counts.  Then whenever we go to process the delete
-	 * everything will be grand and we can account for whatever exclusive
-	 * changes need to be made there.  We also have to pass in old_roots so
-	 * we have an accurate count of the roots as it pertains to this
-	 * operations view of the world.
-	 */
-	ret = qgroup_account_deleted_refs(fs_info, oper, tmp, qgroups, seq,
-					  &old_roots);
-	if (ret < 0)
-		goto out;
-
-	/*
-	 * We are adding our root, need to adjust up the number of roots,
-	 * otherwise old_roots is the number of roots we want.
-	 */
-	if (oper->type == BTRFS_QGROUP_OPER_ADD_SHARED) {
-		new_roots = old_roots + 1;
-	} else {
-		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;
-
-
-	/*
-	 * And now the magic happens, bless Arne for having a pretty elegant
-	 * solution for this.
-	 */
-	qgroup_adjust_counters(fs_info, oper->ref_root, oper->num_bytes,
-			       qgroups, seq, old_roots, new_roots, 0);
-out:
-	spin_unlock(&fs_info->qgroup_lock);
-	ulist_free(qgroups);
-	ulist_free(roots);
-	ulist_free(tmp);
-	return ret;
-}
-
-/*
- * Process a reference to a shared subtree. This type of operation is
- * queued during snapshot removal when we encounter extents which are
- * shared between more than one root.
- */
-static int qgroup_subtree_accounting(struct btrfs_trans_handle *trans,
-				     struct btrfs_fs_info *fs_info,
-				     struct btrfs_qgroup_operation *oper)
-{
-	struct ulist *roots = NULL;
-	struct ulist_node *unode;
-	struct ulist_iterator uiter;
-	struct btrfs_qgroup_list *glist;
-	struct ulist *parents;
-	int ret = 0;
-	int err;
-	struct btrfs_qgroup *qg;
-	u64 root_obj = 0;
-	struct seq_list elem = SEQ_LIST_INIT(elem);
-
-	parents = ulist_alloc(GFP_NOFS);
-	if (!parents)
-		return -ENOMEM;
-
-	btrfs_get_tree_mod_seq(fs_info, &elem);
-	ret = btrfs_find_all_roots(trans, fs_info, oper->bytenr,
-				   elem.seq, &roots);
-	btrfs_put_tree_mod_seq(fs_info, &elem);
-	if (ret < 0)
-		goto out;
-
-	if (roots->nnodes != 1)
-		goto out;
-
-	ULIST_ITER_INIT(&uiter);
-	unode = ulist_next(roots, &uiter); /* Only want 1 so no need to loop */
-	/*
-	 * If we find our ref root then that means all refs
-	 * this extent has to the root have not yet been
-	 * deleted. In that case, we do nothing and let the
-	 * last ref for this bytenr drive our update.
-	 *
-	 * This can happen for example if an extent is
-	 * referenced multiple times in a snapshot (clone,
-	 * etc). If we are in the middle of snapshot removal,
-	 * queued updates for such an extent will find the
-	 * root if we have not yet finished removing the
-	 * snapshot.
-	 */
-	if (unode->val == oper->ref_root)
-		goto out;
-
-	root_obj = unode->val;
-	BUG_ON(!root_obj);
-
-	spin_lock(&fs_info->qgroup_lock);
-	qg = find_qgroup_rb(fs_info, root_obj);
-	if (!qg)
-		goto out_unlock;
-
-	qg->excl += oper->num_bytes;
-	qg->excl_cmpr += oper->num_bytes;
-	qgroup_dirty(fs_info, qg);
-
-	/*
-	 * Adjust counts for parent groups. First we find all
-	 * parents, then in the 2nd loop we do the adjustment
-	 * while adding parents of the parents to our ulist.
-	 */
-	list_for_each_entry(glist, &qg->groups, next_group) {
-		err = ulist_add(parents, glist->group->qgroupid,
-				ptr_to_u64(glist->group), GFP_ATOMIC);
-		if (err < 0) {
-			ret = err;
-			goto out_unlock;
-		}
-	}
-
-	ULIST_ITER_INIT(&uiter);
-	while ((unode = ulist_next(parents, &uiter))) {
-		qg = u64_to_ptr(unode->aux);
-		qg->excl += oper->num_bytes;
-		qg->excl_cmpr += oper->num_bytes;
-		qgroup_dirty(fs_info, qg);
-
-		/* Add any parents of the parents */
-		list_for_each_entry(glist, &qg->groups, next_group) {
-			err = ulist_add(parents, glist->group->qgroupid,
-					ptr_to_u64(glist->group), GFP_ATOMIC);
-			if (err < 0) {
-				ret = err;
-				goto out_unlock;
-			}
-		}
-	}
-
-out_unlock:
-	spin_unlock(&fs_info->qgroup_lock);
-
-out:
-	ulist_free(roots);
-	ulist_free(parents);
-	return ret;
-}
-
-/*
- * 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
- * then the space is accounted accordingly to the different roots. The
- * accounting algorithm works in 3 steps documented inline.
- */
-static int btrfs_qgroup_account(struct btrfs_trans_handle *trans,
-				struct btrfs_fs_info *fs_info,
-				struct btrfs_qgroup_operation *oper)
-{
-	int ret = 0;
-
-	if (!fs_info->quota_enabled)
-		return 0;
-
-	BUG_ON(!fs_info->quota_root);
-
-	mutex_lock(&fs_info->qgroup_rescan_lock);
-	if (fs_info->qgroup_flags & BTRFS_QGROUP_STATUS_FLAG_RESCAN) {
-		if (fs_info->qgroup_rescan_progress.objectid <= oper->bytenr) {
-			mutex_unlock(&fs_info->qgroup_rescan_lock);
-			return 0;
-		}
-	}
-	mutex_unlock(&fs_info->qgroup_rescan_lock);
-
-	ASSERT(is_fstree(oper->ref_root));
-
-	trace_btrfs_qgroup_account(oper);
-
-	switch (oper->type) {
-	case BTRFS_QGROUP_OPER_ADD_EXCL:
-	case BTRFS_QGROUP_OPER_SUB_EXCL:
-		ret = qgroup_excl_accounting(fs_info, oper);
-		break;
-	case BTRFS_QGROUP_OPER_ADD_SHARED:
-	case BTRFS_QGROUP_OPER_SUB_SHARED:
-		ret = qgroup_shared_accounting(trans, fs_info, oper);
-		break;
-	case BTRFS_QGROUP_OPER_SUB_SUBTREE:
-		ret = qgroup_subtree_accounting(trans, fs_info, oper);
-		break;
-	default:
-		ASSERT(0);
-	}
-	return ret;
-}
-
 int
 btrfs_qgroup_account_extent(struct btrfs_trans_handle *trans,
 			    struct btrfs_fs_info *fs_info,
···
 		rb_erase(node, &delayed_refs->dirty_extent_root);
 		kfree(record);
 
-	}
-	return ret;
-}
-
-/*
- * Needs to be called everytime we run delayed refs, even if there is an error
- * in order to cleanup outstanding operations.
- */
-int btrfs_delayed_qgroup_accounting(struct btrfs_trans_handle *trans,
-				    struct btrfs_fs_info *fs_info)
-{
-	struct btrfs_qgroup_operation *oper;
-	int ret = 0;
-
-	while (!list_empty(&trans->qgroup_ref_list)) {
-		oper = list_first_entry(&trans->qgroup_ref_list,
-					struct btrfs_qgroup_operation, list);
-		list_del_init(&oper->list);
-		if (!ret || !trans->aborted)
-			ret = btrfs_qgroup_account(trans, fs_info, oper);
-		spin_lock(&fs_info->qgroup_op_lock);
-		rb_erase(&oper->n, &fs_info->qgroup_op_tree);
-		spin_unlock(&fs_info->qgroup_op_lock);
-		btrfs_put_tree_mod_seq(fs_info, &oper->elem);
-		kfree(oper);
 	}
 	return ret;
 }

fs/btrfs/qgroup.h

···
 #include "delayed-ref.h"
 
 /*
- * A description of the operations, all of these operations only happen when we
- * are adding the 1st reference for that subvolume in the case of adding space
- * or on the last reference delete in the case of subtraction.  The only
- * exception is the last one, which is added for confusion.
- *
- * BTRFS_QGROUP_OPER_ADD_EXCL: adding bytes where this subvolume is the only
- * one pointing at the bytes we are adding.  This is called on the first
- * allocation.
- *
- * BTRFS_QGROUP_OPER_ADD_SHARED: adding bytes where this bytenr is going to be
- * shared between subvols.  This is called on the creation of a ref that already
- * has refs from a different subvolume, so basically reflink.
- *
- * BTRFS_QGROUP_OPER_SUB_EXCL: removing bytes where this subvolume is the only
- * one referencing the range.
- *
- * BTRFS_QGROUP_OPER_SUB_SHARED: removing bytes where this subvolume shares with
- * refs with other subvolumes.
- */
-enum btrfs_qgroup_operation_type {
-	BTRFS_QGROUP_OPER_ADD_EXCL,
-	BTRFS_QGROUP_OPER_ADD_SHARED,
-	BTRFS_QGROUP_OPER_SUB_EXCL,
-	BTRFS_QGROUP_OPER_SUB_SHARED,
-	BTRFS_QGROUP_OPER_SUB_SUBTREE,
-};
-
-struct btrfs_qgroup_operation {
-	u64 ref_root;
-	u64 bytenr;
-	u64 num_bytes;
-	u64 seq;
-	enum btrfs_qgroup_operation_type type;
-	struct seq_list elem;
-	struct rb_node n;
-	struct list_head list;
-};
-
-/*
  * Record a dirty extent, and info qgroup to update quota on it
  * TODO: Use kmem cache to alloc it.
  */
···
 int btrfs_read_qgroup_config(struct btrfs_fs_info *fs_info);
 void btrfs_free_qgroup_config(struct btrfs_fs_info *fs_info);
 struct btrfs_delayed_extent_op;
-int btrfs_qgroup_record_ref(struct btrfs_trans_handle *trans,
-			    struct btrfs_fs_info *fs_info, u64 ref_root,
-			    u64 bytenr, u64 num_bytes,
-			    enum btrfs_qgroup_operation_type type,
-			    int mod_seq);
 int btrfs_qgroup_prepare_account_extents(struct btrfs_trans_handle *trans,
 					 struct btrfs_fs_info *fs_info);
 struct btrfs_qgroup_extent_record
···
 			    struct ulist *old_roots, struct ulist *new_roots);
 int btrfs_qgroup_account_extents(struct btrfs_trans_handle *trans,
 				 struct btrfs_fs_info *fs_info);
-int btrfs_delayed_qgroup_accounting(struct btrfs_trans_handle *trans,
-				    struct btrfs_fs_info *fs_info);
-void btrfs_remove_qgroup_operation(struct btrfs_trans_handle *trans,
-				   struct btrfs_fs_info *fs_info,
-				   struct btrfs_qgroup_operation *oper);
 int btrfs_run_qgroups(struct btrfs_trans_handle *trans,
 		      struct btrfs_fs_info *fs_info);
 int btrfs_qgroup_inherit(struct btrfs_trans_handle *trans,

include/trace/events/btrfs.h

···
 	TP_ARGS(wq)
 );
 
-#define show_oper_type(type)						\
-	__print_symbolic(type,						\
-		{ BTRFS_QGROUP_OPER_ADD_EXCL, 	"OPER_ADD_EXCL" },	\
-		{ BTRFS_QGROUP_OPER_ADD_SHARED, "OPER_ADD_SHARED" },	\
-		{ BTRFS_QGROUP_OPER_SUB_EXCL, 	"OPER_SUB_EXCL" },	\
-		{ BTRFS_QGROUP_OPER_SUB_SHARED,	"OPER_SUB_SHARED" })
-
-DECLARE_EVENT_CLASS(btrfs_qgroup_oper,
-
-	TP_PROTO(struct btrfs_qgroup_operation *oper),
-
-	TP_ARGS(oper),
-
-	TP_STRUCT__entry(
-		__field(	u64,  ref_root		)
-		__field(	u64,  bytenr		)
-		__field(	u64,  num_bytes		)
-		__field(	u64,  seq		)
-		__field(	int,  type		)
-		__field(	u64,  elem_seq		)
-	),
-
-	TP_fast_assign(
-		__entry->ref_root	= oper->ref_root;
-		__entry->bytenr		= oper->bytenr,
-		__entry->num_bytes	= oper->num_bytes;
-		__entry->seq 		= oper->seq;
-		__entry->type		= oper->type;
-		__entry->elem_seq	= oper->elem.seq;
-	),
-
-	TP_printk("ref_root = %llu, bytenr = %llu, num_bytes = %llu, "
-		  "seq = %llu, elem.seq = %llu, type = %s",
-		  (unsigned long long)__entry->ref_root,
-		  (unsigned long long)__entry->bytenr,
-		  (unsigned long long)__entry->num_bytes,
-		  (unsigned long long)__entry->seq,
-		  (unsigned long long)__entry->elem_seq,
-		  show_oper_type(__entry->type))
-);
-
-DEFINE_EVENT(btrfs_qgroup_oper, btrfs_qgroup_account,
-
-	TP_PROTO(struct btrfs_qgroup_operation *oper),
-
-	TP_ARGS(oper)
-);
-
-DEFINE_EVENT(btrfs_qgroup_oper, btrfs_qgroup_record_ref,
-
-	TP_PROTO(struct btrfs_qgroup_operation *oper),
-
-	TP_ARGS(oper)
-);
-
 #endif /* _TRACE_BTRFS_H */
 
 /* This part must be outside protection */