btrfs-progs: check the free space tree in btrfsck

This reuses the existing code for checking the free space cache, we just
need to load the free space tree. While we do that, we check a couple of
invariants on the free space tree itself. This requires pulling in some
code from the kernel to exclude the super stripes.

Signed-off-by: Omar Sandoval <osandov@fb.com>
Signed-off-by: David Sterba <dsterba@suse.com>

1 files changed, 118 insertions, 0 deletions

diff --git a/extent-tree.c b/extent-tree.c
index e04d962..1650bdb 100644
--- a/extent-tree.c
+++ b/extent-tree.c
@@ -4001,3 +4001,121 @@ fail:
 	btrfs_release_path(&path);
 	return ret;
 }
+
+
+static int add_excluded_extent(struct btrfs_root *root,
+			       u64 start, u64 num_bytes)
+{
+	u64 end = start + num_bytes - 1;
+	set_extent_bits(&root->fs_info->pinned_extents,
+			start, end, EXTENT_UPTODATE, GFP_NOFS);
+	return 0;
+}
+
+void free_excluded_extents(struct btrfs_root *root,
+			   struct btrfs_block_group_cache *cache)
+{
+	u64 start, end;
+
+	start = cache->key.objectid;
+	end = start + cache->key.offset - 1;
+
+	clear_extent_bits(&root->fs_info->pinned_extents,
+			  start, end, EXTENT_UPTODATE, GFP_NOFS);
+}
+
+int exclude_super_stripes(struct btrfs_root *root,
+			  struct btrfs_block_group_cache *cache)
+{
+	u64 bytenr;
+	u64 *logical;
+	int stripe_len;
+	int i, nr, ret;
+
+	if (cache->key.objectid < BTRFS_SUPER_INFO_OFFSET) {
+		stripe_len = BTRFS_SUPER_INFO_OFFSET - cache->key.objectid;
+		cache->bytes_super += stripe_len;
+		ret = add_excluded_extent(root, cache->key.objectid,
+					  stripe_len);
+		if (ret)
+			return ret;
+	}
+
+	for (i = 0; i < BTRFS_SUPER_MIRROR_MAX; i++) {
+		bytenr = btrfs_sb_offset(i);
+		ret = btrfs_rmap_block(&root->fs_info->mapping_tree,
+				       cache->key.objectid, bytenr,
+				       0, &logical, &nr, &stripe_len);
+		if (ret)
+			return ret;
+
+		while (nr--) {
+			u64 start, len;
+
+			if (logical[nr] > cache->key.objectid +
+			    cache->key.offset)
+				continue;
+
+			if (logical[nr] + stripe_len <= cache->key.objectid)
+				continue;
+
+			start = logical[nr];
+			if (start < cache->key.objectid) {
+				start = cache->key.objectid;
+				len = (logical[nr] + stripe_len) - start;
+			} else {
+				len = min_t(u64, stripe_len,
+					    cache->key.objectid +
+					    cache->key.offset - start);
+			}
+
+			cache->bytes_super += len;
+			ret = add_excluded_extent(root, start, len);
+			if (ret) {
+				kfree(logical);
+				return ret;
+			}
+		}
+
+		kfree(logical);
+	}
+	return 0;
+}
+
+u64 add_new_free_space(struct btrfs_block_group_cache *block_group,
+		       struct btrfs_fs_info *info, u64 start, u64 end)
+{
+	u64 extent_start, extent_end, size, total_added = 0;
+	int ret;
+
+	while (start < end) {
+		ret = find_first_extent_bit(&info->pinned_extents, start,
+					    &extent_start, &extent_end,
+					    EXTENT_DIRTY | EXTENT_UPTODATE);
+		if (ret)
+			break;
+
+		if (extent_start <= start) {
+			start = extent_end + 1;
+		} else if (extent_start > start && extent_start < end) {
+			size = extent_start - start;
+			total_added += size;
+			ret = btrfs_add_free_space(block_group->free_space_ctl,
+						   start, size);
+			BUG_ON(ret); /* -ENOMEM or logic error */
+			start = extent_end + 1;
+		} else {
+			break;
+		}
+	}
+
+	if (start < end) {
+		size = end - start;
+		total_added += size;
+		ret = btrfs_add_free_space(block_group->free_space_ctl, start,
+					   size);
+		BUG_ON(ret); /* -ENOMEM or logic error */
+	}
+
+	return total_added;
+}