btrfs: qgroup: Introduce btrfs_qgroup_reserve_data function

[linux-2.6-block.git] / fs / btrfs / qgroup.c

diff --git a/fs/btrfs/qgroup.c b/fs/btrfs/qgroup.c
index d904ee1c53497034ed6685b8e12f40d0880aaaca..50662748532a3d461227d8aa80a397385aad607b 100644 (file)
--- a/fs/btrfs/qgroup.c
+++ b/fs/btrfs/qgroup.c
@@ -2486,3 +2486,52 @@ btrfs_qgroup_rescan_resume(struct btrfs_fs_info *fs_info)
                btrfs_queue_work(fs_info->qgroup_rescan_workers,
                                 &fs_info->qgroup_rescan_work);
 }
+
+/*
+ * Reserve qgroup space for range [start, start + len).
+ *
+ * This function will either reserve space from related qgroups or doing
+ * nothing if the range is already reserved.
+ *
+ * Return 0 for successful reserve
+ * Return <0 for error (including -EQUOT)
+ *
+ * NOTE: this function may sleep for memory allocation.
+ */
+int btrfs_qgroup_reserve_data(struct inode *inode, u64 start, u64 len)
+{
+       struct btrfs_root *root = BTRFS_I(inode)->root;
+       struct extent_changeset changeset;
+       struct ulist_node *unode;
+       struct ulist_iterator uiter;
+       int ret;
+
+       if (!root->fs_info->quota_enabled || !is_fstree(root->objectid) ||
+           len == 0)
+               return 0;
+
+       changeset.bytes_changed = 0;
+       changeset.range_changed = ulist_alloc(GFP_NOFS);
+
+       ret = set_record_extent_bits(&BTRFS_I(inode)->io_tree, start,
+                       start + len -1, EXTENT_QGROUP_RESERVED, GFP_NOFS,
+                       &changeset);
+       if (ret < 0)
+               goto cleanup;
+       ret = btrfs_qgroup_reserve(root, changeset.bytes_changed);
+       if (ret < 0)
+               goto cleanup;
+
+       ulist_free(changeset.range_changed);
+       return ret;
+
+cleanup:
+       /* cleanup already reserved ranges */
+       ULIST_ITER_INIT(&uiter);
+       while ((unode = ulist_next(changeset.range_changed, &uiter)))
+               clear_extent_bit(&BTRFS_I(inode)->io_tree, unode->val,
+                                unode->aux, EXTENT_QGROUP_RESERVED, 0, 0, NULL,
+                                GFP_NOFS);
+       ulist_free(changeset.range_changed);
+       return ret;
+}