1 files changed, 671 insertions, 169 deletions

diff --git a/fs/btrfs/qgroup.c b/fs/btrfs/qgroup.c
index b44124dd2370..9d49c586995a 100644
--- a/fs/btrfs/qgroup.c
+++ b/fs/btrfs/qgroup.c
@@ -31,13 +31,13 @@
 #include "locking.h"
 #include "ulist.h"
 #include "backref.h"
+#include "extent_io.h"
 
 /* TODO XXX FIXME
  *  - subvol delete -> delete when ref goes to 0? delete limits also?
  *  - reorganize keys
  *  - compressed
  *  - sync
- *  - rescan
  *  - copy also limits on subvol creation
  *  - limit
  *  - caches fuer ulists
@@ -98,7 +98,15 @@ struct btrfs_qgroup_list {
         struct btrfs_qgroup *member;
 };
 
-/* must be called with qgroup_lock held */
+struct qgroup_rescan {
+        struct btrfs_work       work;
+        struct btrfs_fs_info    *fs_info;
+};
+
+static void qgroup_rescan_start(struct btrfs_fs_info *fs_info,
+                                struct qgroup_rescan *qscan);
+
+/* must be called with qgroup_ioctl_lock held */
 static struct btrfs_qgroup *find_qgroup_rb(struct btrfs_fs_info *fs_info,
                                            u64 qgroupid)
 {
@@ -298,7 +306,20 @@ int btrfs_read_qgroup_config(struct btrfs_fs_info *fs_info)
                         }
                         fs_info->qgroup_flags = btrfs_qgroup_status_flags(l,
                                                                           ptr);
-                        /* FIXME read scan element */
+                        fs_info->qgroup_rescan_progress.objectid =
+                                        btrfs_qgroup_status_rescan(l, ptr);
+                        if (fs_info->qgroup_flags &
+                            BTRFS_QGROUP_STATUS_FLAG_RESCAN) {
+                                struct qgroup_rescan *qscan =
+                                        kmalloc(sizeof(*qscan), GFP_NOFS);
+                                if (!qscan) {
+                                        ret = -ENOMEM;
+                                        goto out;
+                                }
+                                fs_info->qgroup_rescan_progress.type = 0;
+                                fs_info->qgroup_rescan_progress.offset = 0;
+                                qgroup_rescan_start(fs_info, qscan);
+                        }
                         goto next1;
                 }
 
@@ -420,8 +441,6 @@ void btrfs_free_qgroup_config(struct btrfs_fs_info *fs_info)
                 qgroup = rb_entry(n, struct btrfs_qgroup, node);
                 rb_erase(n, &fs_info->qgroup_tree);
 
-                WARN_ON(!list_empty(&qgroup->dirty));
-
                 while (!list_empty(&qgroup->groups)) {
                         list = list_first_entry(&qgroup->groups,
                                                 struct btrfs_qgroup_list,
@@ -721,7 +740,8 @@ static int update_qgroup_status_item(struct btrfs_trans_handle *trans,
         ptr = btrfs_item_ptr(l, slot, struct btrfs_qgroup_status_item);
         btrfs_set_qgroup_status_flags(l, ptr, fs_info->qgroup_flags);
         btrfs_set_qgroup_status_generation(l, ptr, trans->transid);
-        /* XXX scan */
+        btrfs_set_qgroup_status_rescan(l, ptr,
+                                fs_info->qgroup_rescan_progress.objectid);
 
         btrfs_mark_buffer_dirty(l);
 
@@ -783,19 +803,21 @@ int btrfs_quota_enable(struct btrfs_trans_handle *trans,
                        struct btrfs_fs_info *fs_info)
 {
         struct btrfs_root *quota_root;
+        struct btrfs_root *tree_root = fs_info->tree_root;
         struct btrfs_path *path = NULL;
         struct btrfs_qgroup_status_item *ptr;
         struct extent_buffer *leaf;
         struct btrfs_key key;
+        struct btrfs_key found_key;
+        struct btrfs_qgroup *qgroup = NULL;
         int ret = 0;
+        int slot;
 
-        spin_lock(&fs_info->qgroup_lock);
+        mutex_lock(&fs_info->qgroup_ioctl_lock);
         if (fs_info->quota_root) {
                 fs_info->pending_quota_state = 1;
-                spin_unlock(&fs_info->qgroup_lock);
                 goto out;
         }
-        spin_unlock(&fs_info->qgroup_lock);
 
         /*
          * initially create the quota tree
@@ -830,10 +852,57 @@ int btrfs_quota_enable(struct btrfs_trans_handle *trans,
         fs_info->qgroup_flags = BTRFS_QGROUP_STATUS_FLAG_ON |
                                 BTRFS_QGROUP_STATUS_FLAG_INCONSISTENT;
         btrfs_set_qgroup_status_flags(leaf, ptr, fs_info->qgroup_flags);
-        btrfs_set_qgroup_status_scan(leaf, ptr, 0);
+        btrfs_set_qgroup_status_rescan(leaf, ptr, 0);
 
         btrfs_mark_buffer_dirty(leaf);
 
+        key.objectid = 0;
+        key.type = BTRFS_ROOT_REF_KEY;
+        key.offset = 0;
+
+        btrfs_release_path(path);
+        ret = btrfs_search_slot_for_read(tree_root, &key, path, 1, 0);
+        if (ret > 0)
+                goto out_add_root;
+        if (ret < 0)
+                goto out_free_path;
+
+
+        while (1) {
+                slot = path->slots[0];
+                leaf = path->nodes[0];
+                btrfs_item_key_to_cpu(leaf, &found_key, slot);
+
+                if (found_key.type == BTRFS_ROOT_REF_KEY) {
+                        ret = add_qgroup_item(trans, quota_root,
+                                              found_key.offset);
+                        if (ret)
+                                goto out_free_path;
+
+                        qgroup = add_qgroup_rb(fs_info, found_key.offset);
+                        if (IS_ERR(qgroup)) {
+                                ret = PTR_ERR(qgroup);
+                                goto out_free_path;
+                        }
+                }
+                ret = btrfs_next_item(tree_root, path);
+                if (ret < 0)
+                        goto out_free_path;
+                if (ret)
+                        break;
+        }
+
+out_add_root:
+        btrfs_release_path(path);
+        ret = add_qgroup_item(trans, quota_root, BTRFS_FS_TREE_OBJECTID);
+        if (ret)
+                goto out_free_path;
+
+        qgroup = add_qgroup_rb(fs_info, BTRFS_FS_TREE_OBJECTID);
+        if (IS_ERR(qgroup)) {
+                ret = PTR_ERR(qgroup);
+                goto out_free_path;
+        }
         spin_lock(&fs_info->qgroup_lock);
         fs_info->quota_root = quota_root;
         fs_info->pending_quota_state = 1;
@@ -847,6 +916,7 @@ out_free_root:
                 kfree(quota_root);
         }
 out:
+        mutex_unlock(&fs_info->qgroup_ioctl_lock);
         return ret;
 }
 
@@ -857,11 +927,10 @@ int btrfs_quota_disable(struct btrfs_trans_handle *trans,
         struct btrfs_root *quota_root;
         int ret = 0;
 
+        mutex_lock(&fs_info->qgroup_ioctl_lock);
+        if (!fs_info->quota_root)
+                goto out;
         spin_lock(&fs_info->qgroup_lock);
-        if (!fs_info->quota_root) {
-                spin_unlock(&fs_info->qgroup_lock);
-                return 0;
-        }
         fs_info->quota_enabled = 0;
         fs_info->pending_quota_state = 0;
         quota_root = fs_info->quota_root;
@@ -869,8 +938,10 @@ int btrfs_quota_disable(struct btrfs_trans_handle *trans,
         btrfs_free_qgroup_config(fs_info);
         spin_unlock(&fs_info->qgroup_lock);
 
-        if (!quota_root)
-                return -EINVAL;
+        if (!quota_root) {
+                ret = -EINVAL;
+                goto out;
+        }
 
         ret = btrfs_clean_quota_tree(trans, quota_root);
         if (ret)
@@ -891,39 +962,62 @@ int btrfs_quota_disable(struct btrfs_trans_handle *trans,
         free_extent_buffer(quota_root->commit_root);
         kfree(quota_root);
 out:
+        mutex_unlock(&fs_info->qgroup_ioctl_lock);
         return ret;
 }
 
-int btrfs_quota_rescan(struct btrfs_fs_info *fs_info)
+static void qgroup_dirty(struct btrfs_fs_info *fs_info,
+                         struct btrfs_qgroup *qgroup)
 {
-        /* FIXME */
-        return 0;
+        if (list_empty(&qgroup->dirty))
+                list_add(&qgroup->dirty, &fs_info->dirty_qgroups);
 }
 
 int btrfs_add_qgroup_relation(struct btrfs_trans_handle *trans,
                               struct btrfs_fs_info *fs_info, u64 src, u64 dst)
 {
         struct btrfs_root *quota_root;
+        struct btrfs_qgroup *parent;
+        struct btrfs_qgroup *member;
+        struct btrfs_qgroup_list *list;
         int ret = 0;
 
+        mutex_lock(&fs_info->qgroup_ioctl_lock);
         quota_root = fs_info->quota_root;
-        if (!quota_root)
-                return -EINVAL;
+        if (!quota_root) {
+                ret = -EINVAL;
+                goto out;
+        }
+        member = find_qgroup_rb(fs_info, src);
+        parent = find_qgroup_rb(fs_info, dst);
+        if (!member || !parent) {
+                ret = -EINVAL;
+                goto out;
+        }
+
+        /* check if such qgroup relation exist firstly */
+        list_for_each_entry(list, &member->groups, next_group) {
+                if (list->group == parent) {
+                        ret = -EEXIST;
+                        goto out;
+                }
+        }
 
         ret = add_qgroup_relation_item(trans, quota_root, src, dst);
         if (ret)
-                return ret;
+                goto out;
 
         ret = add_qgroup_relation_item(trans, quota_root, dst, src);
         if (ret) {
                 del_qgroup_relation_item(trans, quota_root, src, dst);
-                return ret;
+                goto out;
         }
 
         spin_lock(&fs_info->qgroup_lock);
         ret = add_relation_rb(quota_root->fs_info, src, dst);
         spin_unlock(&fs_info->qgroup_lock);
-
+out:
+        mutex_unlock(&fs_info->qgroup_ioctl_lock);
         return ret;
 }
 
@@ -931,13 +1025,34 @@ int btrfs_del_qgroup_relation(struct btrfs_trans_handle *trans,
                               struct btrfs_fs_info *fs_info, u64 src, u64 dst)
 {
         struct btrfs_root *quota_root;
+        struct btrfs_qgroup *parent;
+        struct btrfs_qgroup *member;
+        struct btrfs_qgroup_list *list;
         int ret = 0;
         int err;
 
+        mutex_lock(&fs_info->qgroup_ioctl_lock);
         quota_root = fs_info->quota_root;
-        if (!quota_root)
-                return -EINVAL;
+        if (!quota_root) {
+                ret = -EINVAL;
+                goto out;
+        }
 
+        member = find_qgroup_rb(fs_info, src);
+        parent = find_qgroup_rb(fs_info, dst);
+        if (!member || !parent) {
+                ret = -EINVAL;
+                goto out;
+        }
+
+        /* check if such qgroup relation exist firstly */
+        list_for_each_entry(list, &member->groups, next_group) {
+                if (list->group == parent)
+                        goto exist;
+        }
+        ret = -ENOENT;
+        goto out;
+exist:
         ret = del_qgroup_relation_item(trans, quota_root, src, dst);
         err = del_qgroup_relation_item(trans, quota_root, dst, src);
         if (err && !ret)
@@ -945,9 +1060,9 @@ int btrfs_del_qgroup_relation(struct btrfs_trans_handle *trans,
 
         spin_lock(&fs_info->qgroup_lock);
         del_relation_rb(fs_info, src, dst);
-
         spin_unlock(&fs_info->qgroup_lock);
-
+out:
+        mutex_unlock(&fs_info->qgroup_ioctl_lock);
         return ret;
 }
 
@@ -958,11 +1073,21 @@ int btrfs_create_qgroup(struct btrfs_trans_handle *trans,
         struct btrfs_qgroup *qgroup;
         int ret = 0;
 
+        mutex_lock(&fs_info->qgroup_ioctl_lock);
         quota_root = fs_info->quota_root;
-        if (!quota_root)
-                return -EINVAL;
+        if (!quota_root) {
+                ret = -EINVAL;
+                goto out;
+        }
+        qgroup = find_qgroup_rb(fs_info, qgroupid);
+        if (qgroup) {
+                ret = -EEXIST;
+                goto out;
+        }
 
         ret = add_qgroup_item(trans, quota_root, qgroupid);
+        if (ret)
+                goto out;
 
         spin_lock(&fs_info->qgroup_lock);
         qgroup = add_qgroup_rb(fs_info, qgroupid);
@@ -970,7 +1095,8 @@ int btrfs_create_qgroup(struct btrfs_trans_handle *trans,
 
         if (IS_ERR(qgroup))
                 ret = PTR_ERR(qgroup);
-
+out:
+        mutex_unlock(&fs_info->qgroup_ioctl_lock);
         return ret;
 }
 
@@ -981,27 +1107,32 @@ int btrfs_remove_qgroup(struct btrfs_trans_handle *trans,
         struct btrfs_qgroup *qgroup;
         int ret = 0;
 
+        mutex_lock(&fs_info->qgroup_ioctl_lock);
         quota_root = fs_info->quota_root;
-        if (!quota_root)
-                return -EINVAL;
+        if (!quota_root) {
+                ret = -EINVAL;
+                goto out;
+        }
 
-        /* check if there are no relations to this qgroup */
-        spin_lock(&fs_info->qgroup_lock);
         qgroup = find_qgroup_rb(fs_info, qgroupid);
-        if (qgroup) {
-                if (!list_empty(&qgroup->groups) || !list_empty(&qgroup->members)) {
-                        spin_unlock(&fs_info->qgroup_lock);
-                        return -EBUSY;
+        if (!qgroup) {
+                ret = -ENOENT;
+                goto out;
+        } else {
+                /* check if there are no relations to this qgroup */
+                if (!list_empty(&qgroup->groups) ||
+                    !list_empty(&qgroup->members)) {
+                        ret = -EBUSY;
+                        goto out;
                 }
         }
-        spin_unlock(&fs_info->qgroup_lock);
-
         ret = del_qgroup_item(trans, quota_root, qgroupid);
 
         spin_lock(&fs_info->qgroup_lock);
         del_qgroup_rb(quota_root->fs_info, qgroupid);
         spin_unlock(&fs_info->qgroup_lock);
-
+out:
+        mutex_unlock(&fs_info->qgroup_ioctl_lock);
         return ret;
 }
 
@@ -1009,13 +1140,22 @@ int btrfs_limit_qgroup(struct btrfs_trans_handle *trans,
                        struct btrfs_fs_info *fs_info, u64 qgroupid,
                        struct btrfs_qgroup_limit *limit)
 {
-        struct btrfs_root *quota_root = fs_info->quota_root;
+        struct btrfs_root *quota_root;
         struct btrfs_qgroup *qgroup;
         int ret = 0;
 
-        if (!quota_root)
-                return -EINVAL;
+        mutex_lock(&fs_info->qgroup_ioctl_lock);
+        quota_root = fs_info->quota_root;
+        if (!quota_root) {
+                ret = -EINVAL;
+                goto out;
+        }
 
+        qgroup = find_qgroup_rb(fs_info, qgroupid);
+        if (!qgroup) {
+                ret = -ENOENT;
+                goto out;
+        }
         ret = update_qgroup_limit_item(trans, quota_root, qgroupid,
                                        limit->flags, limit->max_rfer,
                                        limit->max_excl, limit->rsv_rfer,
@@ -1027,31 +1167,17 @@ int btrfs_limit_qgroup(struct btrfs_trans_handle *trans,
         }
 
         spin_lock(&fs_info->qgroup_lock);
-
-        qgroup = find_qgroup_rb(fs_info, qgroupid);
-        if (!qgroup) {
-                ret = -ENOENT;
-                goto unlock;
-        }
         qgroup->lim_flags = limit->flags;
         qgroup->max_rfer = limit->max_rfer;
         qgroup->max_excl = limit->max_excl;
         qgroup->rsv_rfer = limit->rsv_rfer;
         qgroup->rsv_excl = limit->rsv_excl;
-
-unlock:
         spin_unlock(&fs_info->qgroup_lock);
-
+out:
+        mutex_unlock(&fs_info->qgroup_ioctl_lock);
         return ret;
 }
 
-static void qgroup_dirty(struct btrfs_fs_info *fs_info,
-                         struct btrfs_qgroup *qgroup)
-{
-        if (list_empty(&qgroup->dirty))
-                list_add(&qgroup->dirty, &fs_info->dirty_qgroups);
-}
-
 /*
  * btrfs_qgroup_record_ref is called when the ref is added or deleted. it puts
  * the modification into a list that's later used by btrfs_end_transaction to
@@ -1075,6 +1201,144 @@ 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
@@ -1090,10 +1354,8 @@ 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;
@@ -1132,9 +1394,11 @@ int btrfs_qgroup_account_ref(struct btrfs_trans_handle *trans,
         case BTRFS_ADD_DELAYED_REF:
         case BTRFS_ADD_DELAYED_EXTENT:
                 sgn = 1;
+                seq = btrfs_tree_mod_seq_prev(node->seq);
                 break;
         case BTRFS_DROP_DELAYED_REF:
                 sgn = -1;
+                seq = node->seq;
                 break;
         case BTRFS_UPDATE_DELAYED_HEAD:
                 return 0;
@@ -1142,20 +1406,37 @@ int btrfs_qgroup_account_ref(struct btrfs_trans_handle *trans,
                 BUG();
         }
 
+        mutex_lock(&fs_info->qgroup_rescan_lock);
+        if (fs_info->qgroup_flags & BTRFS_QGROUP_STATUS_FLAG_RESCAN) {
+                if (fs_info->qgroup_rescan_progress.objectid <= node->bytenr) {
+                        mutex_unlock(&fs_info->qgroup_rescan_lock);
+                        return 0;
+                }
+        }
+        mutex_unlock(&fs_info->qgroup_rescan_lock);
+
         /*
          * the delayed ref sequence number we pass depends on the direction of
-         * the operation. for add operations, we pass (node->seq - 1) to skip
+         * the operation. for add operations, we pass
+         * tree_mod_log_prev_seq(node->seq) to skip
          * the delayed ref's current sequence number, because we need the state
          * of the tree before the add operation. for delete operations, we pass
          * (node->seq) to include the delayed ref's current sequence number,
          * because we need the state of the tree after the delete operation.
          */
-        ret = btrfs_find_all_roots(trans, fs_info, node->bytenr,
-                                   sgn > 0 ? node->seq - 1 : node->seq, &roots);
+        ret = btrfs_find_all_roots(trans, fs_info, node->bytenr, seq, &roots);
         if (ret < 0)
                 return ret;
 
+        mutex_lock(&fs_info->qgroup_rescan_lock);
         spin_lock(&fs_info->qgroup_lock);
+        if (fs_info->qgroup_flags & BTRFS_QGROUP_STATUS_FLAG_RESCAN) {
+                if (fs_info->qgroup_rescan_progress.objectid <= node->bytenr) {
+                        ret = 0;
+                        goto unlock;
+                }
+        }
+
         quota_root = fs_info->quota_root;
         if (!quota_root)
                 goto unlock;
@@ -1175,106 +1456,29 @@ 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 */
-                ulist_add(tmp, qg->qgroupid, (u64)(uintptr_t)qg, GFP_ATOMIC);
-                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) {
-                                ulist_add(tmp, glist->group->qgroupid,
-                                          (u64)(uintptr_t)glist->group,
-                                          GFP_ATOMIC);
-                        }
-                }
-        }
+        ret = qgroup_account_ref_step1(fs_info, roots, tmp, seq);
+        if (ret)
+                goto unlock;
 
         /*
          * step 2: walk from the new root
          */
-        ulist_reinit(tmp);
-        ulist_add(tmp, qgroup->qgroupid, (uintptr_t)qgroup, GFP_ATOMIC);
-        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) {
-                        ulist_add(tmp, glist->group->qgroupid,
-                                  (uintptr_t)glist->group, GFP_ATOMIC);
-                }
-        }
+        ret = qgroup_account_ref_step2(fs_info, roots, tmp, seq, sgn,
+                                       node->num_bytes, qgroup);
+        if (ret)
+                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);
-                ulist_add(tmp, qg->qgroupid, (uintptr_t)qg, GFP_ATOMIC);
-                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) {
-                                ulist_add(tmp, glist->group->qgroupid,
-                                          (uintptr_t)glist->group,
-                                          GFP_ATOMIC);
-                        }
-                }
-        }
-        ret = 0;
 unlock:
         spin_unlock(&fs_info->qgroup_lock);
+        mutex_unlock(&fs_info->qgroup_rescan_lock);
         ulist_free(roots);
         ulist_free(tmp);
 
@@ -1289,10 +1493,14 @@ int btrfs_run_qgroups(struct btrfs_trans_handle *trans,
 {
         struct btrfs_root *quota_root = fs_info->quota_root;
         int ret = 0;
+        int start_rescan_worker = 0;
 
         if (!quota_root)
                 goto out;
 
+        if (!fs_info->quota_enabled && fs_info->pending_quota_state)
+                start_rescan_worker = 1;
+
         fs_info->quota_enabled = fs_info->pending_quota_state;
 
         spin_lock(&fs_info->qgroup_lock);
@@ -1318,6 +1526,13 @@ int btrfs_run_qgroups(struct btrfs_trans_handle *trans,
         if (ret)
                 fs_info->qgroup_flags |= BTRFS_QGROUP_STATUS_FLAG_INCONSISTENT;
 
+        if (!ret && start_rescan_worker) {
+                ret = btrfs_qgroup_rescan(fs_info);
+                if (ret)
+                        pr_err("btrfs: start rescan quota failed: %d\n", ret);
+                ret = 0;
+        }
+
 out:
 
         return ret;
@@ -1338,12 +1553,30 @@ int btrfs_qgroup_inherit(struct btrfs_trans_handle *trans,
         struct btrfs_qgroup *srcgroup;
         struct btrfs_qgroup *dstgroup;
         u32 level_size = 0;
+        u64 nums;
 
+        mutex_lock(&fs_info->qgroup_ioctl_lock);
         if (!fs_info->quota_enabled)
-                return 0;
+                goto out;
 
-        if (!quota_root)
-                return -EINVAL;
+        if (!quota_root) {
+                ret = -EINVAL;
+                goto out;
+        }
+
+        if (inherit) {
+                i_qgroups = (u64 *)(inherit + 1);
+                nums = inherit->num_qgroups + 2 * inherit->num_ref_copies +
+                       2 * inherit->num_excl_copies;
+                for (i = 0; i < nums; ++i) {
+                        srcgroup = find_qgroup_rb(fs_info, *i_qgroups);
+                        if (!srcgroup) {
+                                ret = -EINVAL;
+                                goto out;
+                        }
+                        ++i_qgroups;
+                }
+        }
 
         /*
          * create a tracking group for the subvol itself
@@ -1470,6 +1703,7 @@ int btrfs_qgroup_inherit(struct btrfs_trans_handle *trans,
 unlock:
         spin_unlock(&fs_info->qgroup_lock);
 out:
+        mutex_unlock(&fs_info->qgroup_ioctl_lock);
         return ret;
 }
 
@@ -1514,7 +1748,10 @@ int btrfs_qgroup_reserve(struct btrfs_root *root, u64 num_bytes)
                 ret = -ENOMEM;
                 goto out;
         }
-        ulist_add(ulist, qgroup->qgroupid, (uintptr_t)qgroup, GFP_ATOMIC);
+        ret = ulist_add(ulist, qgroup->qgroupid,
+                        (uintptr_t)qgroup, GFP_ATOMIC);
+        if (ret < 0)
+                goto out;
         ULIST_ITER_INIT(&uiter);
         while ((unode = ulist_next(ulist, &uiter))) {
                 struct btrfs_qgroup *qg;
@@ -1523,25 +1760,27 @@ int btrfs_qgroup_reserve(struct btrfs_root *root, u64 num_bytes)
                 qg = (struct btrfs_qgroup *)(uintptr_t)unode->aux;
 
                 if ((qg->lim_flags & BTRFS_QGROUP_LIMIT_MAX_RFER) &&
-                    qg->reserved + qg->rfer + num_bytes >
+                    qg->reserved + (s64)qg->rfer + num_bytes >
                     qg->max_rfer) {
                         ret = -EDQUOT;
                         goto out;
                 }
 
                 if ((qg->lim_flags & BTRFS_QGROUP_LIMIT_MAX_EXCL) &&
-                    qg->reserved + qg->excl + num_bytes >
+                    qg->reserved + (s64)qg->excl + num_bytes >
                     qg->max_excl) {
                         ret = -EDQUOT;
                         goto out;
                 }
 
                 list_for_each_entry(glist, &qg->groups, next_group) {
-                        ulist_add(ulist, glist->group->qgroupid,
-                                  (uintptr_t)glist->group, GFP_ATOMIC);
+                        ret = ulist_add(ulist, glist->group->qgroupid,
+                                        (uintptr_t)glist->group, GFP_ATOMIC);
+                        if (ret < 0)
+                                goto out;
                 }
         }
-
+        ret = 0;
         /*
          * no limits exceeded, now record the reservation into all qgroups
          */
@@ -1570,6 +1809,7 @@ void btrfs_qgroup_free(struct btrfs_root *root, u64 num_bytes)
         struct ulist_node *unode;
         struct ulist_iterator uiter;
         u64 ref_root = root->root_key.objectid;
+        int ret = 0;
 
         if (!is_fstree(ref_root))
                 return;
@@ -1592,7 +1832,10 @@ void btrfs_qgroup_free(struct btrfs_root *root, u64 num_bytes)
                 btrfs_std_error(fs_info, -ENOMEM);
                 goto out;
         }
-        ulist_add(ulist, qgroup->qgroupid, (uintptr_t)qgroup, GFP_ATOMIC);
+        ret = ulist_add(ulist, qgroup->qgroupid,
+                        (uintptr_t)qgroup, GFP_ATOMIC);
+        if (ret < 0)
+                goto out;
         ULIST_ITER_INIT(&uiter);
         while ((unode = ulist_next(ulist, &uiter))) {
                 struct btrfs_qgroup *qg;
@@ -1603,8 +1846,10 @@ void btrfs_qgroup_free(struct btrfs_root *root, u64 num_bytes)
                 qg->reserved -= num_bytes;
 
                 list_for_each_entry(glist, &qg->groups, next_group) {
-                        ulist_add(ulist, glist->group->qgroupid,
-                                  (uintptr_t)glist->group, GFP_ATOMIC);
+                        ret = ulist_add(ulist, glist->group->qgroupid,
+                                        (uintptr_t)glist->group, GFP_ATOMIC);
+                        if (ret < 0)
+                                goto out;
                 }
         }
 
@@ -1617,8 +1862,265 @@ void assert_qgroups_uptodate(struct btrfs_trans_handle *trans)
 {
         if (list_empty(&trans->qgroup_ref_list) && !trans->delayed_ref_elem.seq)
                 return;
-        printk(KERN_ERR "btrfs: qgroups not uptodate in trans handle %p: list is%s empty, seq is %llu\n",
+        pr_err("btrfs: qgroups not uptodate in trans handle %p: list is%s empty, seq is %#x.%x\n",
                 trans, list_empty(&trans->qgroup_ref_list) ? "" : " not",
-                trans->delayed_ref_elem.seq);
+                (u32)(trans->delayed_ref_elem.seq >> 32),
+                (u32)trans->delayed_ref_elem.seq);
         BUG();
 }
+
+/*
+ * returns < 0 on error, 0 when more leafs are to be scanned.
+ * returns 1 when done, 2 when done and FLAG_INCONSISTENT was cleared.
+ */
+static int
+qgroup_rescan_leaf(struct qgroup_rescan *qscan, struct btrfs_path *path,
+                   struct btrfs_trans_handle *trans, struct ulist *tmp,
+                   struct extent_buffer *scratch_leaf)
+{
+        struct btrfs_key found;
+        struct btrfs_fs_info *fs_info = qscan->fs_info;
+        struct ulist *roots = NULL;
+        struct ulist_node *unode;
+        struct ulist_iterator uiter;
+        struct seq_list tree_mod_seq_elem = {};
+        u64 seq;
+        int slot;
+        int ret;
+
+        path->leave_spinning = 1;
+        mutex_lock(&fs_info->qgroup_rescan_lock);
+        ret = btrfs_search_slot_for_read(fs_info->extent_root,
+                                         &fs_info->qgroup_rescan_progress,
+                                         path, 1, 0);
+
+        pr_debug("current progress key (%llu %u %llu), search_slot ret %d\n",
+                 (unsigned long long)fs_info->qgroup_rescan_progress.objectid,
+                 fs_info->qgroup_rescan_progress.type,
+                 (unsigned long long)fs_info->qgroup_rescan_progress.offset,
+                 ret);
+
+        if (ret) {
+                /*
+                 * The rescan is about to end, we will not be scanning any
+                 * further blocks. We cannot unset the RESCAN flag here, because
+                 * we want to commit the transaction if everything went well.
+                 * To make the live accounting work in this phase, we set our
+                 * scan progress pointer such that every real extent objectid
+                 * will be smaller.
+                 */
+                fs_info->qgroup_rescan_progress.objectid = (u64)-1;
+                btrfs_release_path(path);
+                mutex_unlock(&fs_info->qgroup_rescan_lock);
+                return ret;
+        }
+
+        btrfs_item_key_to_cpu(path->nodes[0], &found,
+                              btrfs_header_nritems(path->nodes[0]) - 1);
+        fs_info->qgroup_rescan_progress.objectid = found.objectid + 1;
+
+        btrfs_get_tree_mod_seq(fs_info, &tree_mod_seq_elem);
+        memcpy(scratch_leaf, path->nodes[0], sizeof(*scratch_leaf));
+        slot = path->slots[0];
+        btrfs_release_path(path);
+        mutex_unlock(&fs_info->qgroup_rescan_lock);
+
+        for (; slot < btrfs_header_nritems(scratch_leaf); ++slot) {
+                btrfs_item_key_to_cpu(scratch_leaf, &found, slot);
+                if (found.type != BTRFS_EXTENT_ITEM_KEY)
+                        continue;
+                ret = btrfs_find_all_roots(trans, fs_info, found.objectid,
+                                           tree_mod_seq_elem.seq, &roots);
+                if (ret < 0)
+                        goto out;
+                spin_lock(&fs_info->qgroup_lock);
+                seq = fs_info->qgroup_seq;
+                fs_info->qgroup_seq += roots->nnodes + 1; /* max refcnt */
+
+                ret = qgroup_account_ref_step1(fs_info, roots, tmp, seq);
+                if (ret) {
+                        spin_unlock(&fs_info->qgroup_lock);
+                        ulist_free(roots);
+                        goto out;
+                }
+
+                /*
+                 * step2 of btrfs_qgroup_account_ref works from a single root,
+                 * we're doing all at once here.
+                 */
+                ulist_reinit(tmp);
+                ULIST_ITER_INIT(&uiter);
+                while ((unode = ulist_next(roots, &uiter))) {
+                        struct btrfs_qgroup *qg;
+
+                        qg = find_qgroup_rb(fs_info, unode->val);
+                        if (!qg)
+                                continue;
+
+                        ret = ulist_add(tmp, qg->qgroupid, (uintptr_t)qg,
+                                        GFP_ATOMIC);
+                        if (ret < 0) {
+                                spin_unlock(&fs_info->qgroup_lock);
+                                ulist_free(roots);
+                                goto out;
+                        }
+                }
+
+                /* this loop is similar to step 2 of btrfs_qgroup_account_ref */
+                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;
+                        qg->rfer += found.offset;
+                        qg->rfer_cmpr += found.offset;
+                        WARN_ON(qg->tag >= seq);
+                        if (qg->refcnt - seq == roots->nnodes) {
+                                qg->excl += found.offset;
+                                qg->excl_cmpr += found.offset;
+                        }
+                        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) {
+                                        spin_unlock(&fs_info->qgroup_lock);
+                                        ulist_free(roots);
+                                        goto out;
+                                }
+                        }
+                }
+
+                spin_unlock(&fs_info->qgroup_lock);
+                ulist_free(roots);
+                ret = 0;
+        }
+
+out:
+        btrfs_put_tree_mod_seq(fs_info, &tree_mod_seq_elem);
+
+        return ret;
+}
+
+static void btrfs_qgroup_rescan_worker(struct btrfs_work *work)
+{
+        struct qgroup_rescan *qscan = container_of(work, struct qgroup_rescan,
+                                                   work);
+        struct btrfs_path *path;
+        struct btrfs_trans_handle *trans = NULL;
+        struct btrfs_fs_info *fs_info = qscan->fs_info;
+        struct ulist *tmp = NULL;
+        struct extent_buffer *scratch_leaf = NULL;
+        int err = -ENOMEM;
+
+        path = btrfs_alloc_path();
+        if (!path)
+                goto out;
+        tmp = ulist_alloc(GFP_NOFS);
+        if (!tmp)
+                goto out;
+        scratch_leaf = kmalloc(sizeof(*scratch_leaf), GFP_NOFS);
+        if (!scratch_leaf)
+                goto out;
+
+        err = 0;
+        while (!err) {
+                trans = btrfs_start_transaction(fs_info->fs_root, 0);
+                if (IS_ERR(trans)) {
+                        err = PTR_ERR(trans);
+                        break;
+                }
+                if (!fs_info->quota_enabled) {
+                        err = -EINTR;
+                } else {
+                        err = qgroup_rescan_leaf(qscan, path, trans,
+                                                 tmp, scratch_leaf);
+                }
+                if (err > 0)
+                        btrfs_commit_transaction(trans, fs_info->fs_root);
+                else
+                        btrfs_end_transaction(trans, fs_info->fs_root);
+        }
+
+out:
+        kfree(scratch_leaf);
+        ulist_free(tmp);
+        btrfs_free_path(path);
+        kfree(qscan);
+
+        mutex_lock(&fs_info->qgroup_rescan_lock);
+        fs_info->qgroup_flags &= ~BTRFS_QGROUP_STATUS_FLAG_RESCAN;
+
+        if (err == 2 &&
+            fs_info->qgroup_flags & BTRFS_QGROUP_STATUS_FLAG_INCONSISTENT) {
+                fs_info->qgroup_flags &= ~BTRFS_QGROUP_STATUS_FLAG_INCONSISTENT;
+        } else if (err < 0) {
+                fs_info->qgroup_flags |= BTRFS_QGROUP_STATUS_FLAG_INCONSISTENT;
+        }
+        mutex_unlock(&fs_info->qgroup_rescan_lock);
+
+        if (err >= 0) {
+                pr_info("btrfs: qgroup scan completed%s\n",
+                        err == 2 ? " (inconsistency flag cleared)" : "");
+        } else {
+                pr_err("btrfs: qgroup scan failed with %d\n", err);
+        }
+}
+
+static void
+qgroup_rescan_start(struct btrfs_fs_info *fs_info, struct qgroup_rescan *qscan)
+{
+        memset(&qscan->work, 0, sizeof(qscan->work));
+        qscan->work.func = btrfs_qgroup_rescan_worker;
+        qscan->fs_info = fs_info;
+
+        pr_info("btrfs: qgroup scan started\n");
+        btrfs_queue_worker(&fs_info->qgroup_rescan_workers, &qscan->work);
+}
+
+int
+btrfs_qgroup_rescan(struct btrfs_fs_info *fs_info)
+{
+        int ret = 0;
+        struct rb_node *n;
+        struct btrfs_qgroup *qgroup;
+        struct qgroup_rescan *qscan = kmalloc(sizeof(*qscan), GFP_NOFS);
+
+        if (!qscan)
+                return -ENOMEM;
+
+        mutex_lock(&fs_info->qgroup_rescan_lock);
+        spin_lock(&fs_info->qgroup_lock);
+        if (fs_info->qgroup_flags & BTRFS_QGROUP_STATUS_FLAG_RESCAN)
+                ret = -EINPROGRESS;
+        else if (!(fs_info->qgroup_flags & BTRFS_QGROUP_STATUS_FLAG_ON))
+                ret = -EINVAL;
+        if (ret) {
+                spin_unlock(&fs_info->qgroup_lock);
+                mutex_unlock(&fs_info->qgroup_rescan_lock);
+                kfree(qscan);
+                return ret;
+        }
+
+        fs_info->qgroup_flags |= BTRFS_QGROUP_STATUS_FLAG_RESCAN;
+        memset(&fs_info->qgroup_rescan_progress, 0,
+                sizeof(fs_info->qgroup_rescan_progress));
+
+        /* clear all current qgroup tracking information */
+        for (n = rb_first(&fs_info->qgroup_tree); n; n = rb_next(n)) {
+                qgroup = rb_entry(n, struct btrfs_qgroup, node);
+                qgroup->rfer = 0;
+                qgroup->rfer_cmpr = 0;
+                qgroup->excl = 0;
+                qgroup->excl_cmpr = 0;
+        }
+        spin_unlock(&fs_info->qgroup_lock);
+        mutex_unlock(&fs_info->qgroup_rescan_lock);
+
+        qgroup_rescan_start(fs_info, qscan);
+
+        return 0;
+}