btrfs: qgroup: Introduce functions to release/free qgroup reserve data

[mirror_ubuntu-bionic-kernel.git] / fs / btrfs / qgroup.c

diff --git a/fs/btrfs/qgroup.c b/fs/btrfs/qgroup.c
index 50662748532a3d461227d8aa80a397385aad607b..e05d1f6aa293f0e95768032c96ba225777036f10 100644 (file)
--- a/fs/btrfs/qgroup.c
+++ b/fs/btrfs/qgroup.c
@@ -2535,3 +2535,63 @@ cleanup:
        ulist_free(changeset.range_changed);
        return ret;
 }
+
+static int __btrfs_qgroup_release_data(struct inode *inode, u64 start, u64 len,
+                                      int free)
+{
+       struct extent_changeset changeset;
+       int ret;
+
+       changeset.bytes_changed = 0;
+       changeset.range_changed = ulist_alloc(GFP_NOFS);
+       if (!changeset.range_changed)
+               return -ENOMEM;
+
+       ret = clear_record_extent_bits(&BTRFS_I(inode)->io_tree, start, 
+                       start + len -1, EXTENT_QGROUP_RESERVED, GFP_NOFS,
+                       &changeset);
+       if (ret < 0)
+               goto out;
+
+       if (free)
+               btrfs_qgroup_free(BTRFS_I(inode)->root,
+                                 changeset.bytes_changed);
+out:
+       ulist_free(changeset.range_changed);
+       return ret;
+}
+
+/*
+ * Free a reserved space range from io_tree and related qgroups
+ *
+ * Should be called when a range of pages get invalidated before reaching disk.
+ * Or for error cleanup case.
+ *
+ * For data written to disk, use btrfs_qgroup_release_data().
+ *
+ * NOTE: This function may sleep for memory allocation.
+ */
+int btrfs_qgroup_free_data(struct inode *inode, u64 start, u64 len)
+{
+       return __btrfs_qgroup_release_data(inode, start, len, 1);
+}
+
+/*
+ * Release a reserved space range from io_tree only.
+ *
+ * Should be called when a range of pages get written to disk and corresponding
+ * FILE_EXTENT is inserted into corresponding root.
+ *
+ * Since new qgroup accounting framework will only update qgroup numbers at
+ * commit_transaction() time, its reserved space shouldn't be freed from
+ * related qgroups.
+ *
+ * But we should release the range from io_tree, to allow further write to be
+ * COWed.
+ *
+ * NOTE: This function may sleep for memory allocation.
+ */
+int btrfs_qgroup_release_data(struct inode *inode, u64 start, u64 len)
+{
+       return __btrfs_qgroup_release_data(inode, start, len, 0);
+}