@@ -2521,6 +2521,123 @@ static int convert_open_fs(const char *devname,
}
/*
+ * Remove one reserve range from given cache tree
+ * if min_stripe_size is non-zero, it will ensure for split case,
+ * all its split cache extent is no smaller than @min_strip_size / 2.
+ */
+static int wipe_one_reserved_range(struct cache_tree *tree,
+ u64 start, u64 len, u64 min_stripe_size,
+ int ensure_size)
+{
+ struct cache_extent *cache;
+ int ret;
+
+ BUG_ON(ensure_size && min_stripe_size == 0);
+ /*
+ * The logical here is simplified to handle special cases only
+ * So we don't need to consider merge case for ensure_size
+ */
+ BUG_ON(min_stripe_size && (min_stripe_size < len * 2 ||
+ min_stripe_size / 2 < BTRFS_STRIPE_LEN));
+
+ /* Also, wipe range should already be aligned */
+ BUG_ON(start != round_down(start, BTRFS_STRIPE_LEN) ||
+ start + len != round_up(start + len, BTRFS_STRIPE_LEN));
+
+ min_stripe_size /= 2;
+
+ cache = lookup_cache_extent(tree, start, len);
+ if (!cache)
+ return 0;
+
+ if (start <= cache->start) {
+ /*
+ * |--------cache---------|
+ * |-wipe-|
+ */
+ BUG_ON(start + len <= cache->start);
+
+ /*
+ * The wipe size is smaller than min_stripe_size / 2,
+ * so the result length should still meet min_stripe_size
+ * And no need to do alignment
+ */
+ cache->size -= (start + len - cache->start);
+ if (cache->size == 0) {
+ remove_cache_extent(tree, cache);
+ free(cache);
+ return 0;
+ }
+
+ BUG_ON(ensure_size && cache->size < min_stripe_size);
+
+ cache->start = start + len;
+ return 0;
+ } else if (start > cache->start && start + len < cache->start +
+ cache->size) {
+ /*
+ * |-------cache-----|
+ * |-wipe-|
+ */
+ u64 old_len = cache->size;
+ u64 insert_start = start + len;
+ u64 insert_len;
+
+ cache->size = start - cache->start;
+ if (ensure_size)
+ cache->size = max(cache->size, min_stripe_size);
+ cache->start = start - cache->size;
+
+ /* And insert the new one */
+ insert_len = old_len - start - len;
+ if (ensure_size)
+ insert_len = max(insert_len, min_stripe_size);
+
+ ret = add_merge_cache_extent(tree, insert_start, insert_len);
+ return ret;
+ }
+ /*
+ * |----cache-----|
+ * |--wipe-|
+ * Wipe len should be small enough and no need to expand the
+ * remaining extent
+ */
+ cache->size = start - cache->start;
+ BUG_ON(ensure_size && cache->size < min_stripe_size);
+ return 0;
+}
+
+/*
+ * Remove reserved ranges from given cache_tree
+ *
+ * It will remove the following ranges
+ * 1) 0~1M
+ * 2) 2nd superblock, +64K(make sure chunks are 64K aligned)
+ * 3) 3rd superblock, +64K
+ *
+ * @min_stripe must be given for safety check
+ * and if @ensure_size is given, it will ensure affected cache_extent will be
+ * larger than min_stripe_size
+ */
+static int wipe_reserved_ranges(struct cache_tree *tree, u64 min_stripe_size,
+ int ensure_size)
+{
+ int ret;
+
+ ret = wipe_one_reserved_range(tree, 0, 1024 * 1024, min_stripe_size,
+ ensure_size);
+ if (ret < 0)
+ return ret;
+ ret = wipe_one_reserved_range(tree, btrfs_sb_offset(1),
+ BTRFS_STRIPE_LEN, min_stripe_size, ensure_size);
+ if (ret < 0)
+ return ret;
+ ret = wipe_one_reserved_range(tree, btrfs_sb_offset(2),
+ BTRFS_STRIPE_LEN, min_stripe_size, ensure_size);
+ return ret;
+}
+
+/*
* Read used space
*/
static int convert_read_used_space(struct btrfs_convert_context *cctx)