btrfs-progs: check: make low memory mode support partially dropped snapshots

Signed-off-by: Wang Xiaoguang <wangxg.fnst@cn.fujitsu.com>
Signed-off-by: David Sterba <dsterba@suse.com>

diff --git a/cmds-check.c b/cmds-check.c
index a453696..df97d3b 100644 (file)
--- a/cmds-check.c
+++ b/cmds-check.c
@@ -9063,9 +9063,10 @@ static int check_tree_block_backref(struct btrfs_fs_info *fs_info, u64 root_id,
        free_extent_buffer(eb);
 
        btrfs_init_path(&path);
+       path.lowest_level = level;
        /* Search with the first key, to ensure we can reach it */
        ret = btrfs_search_slot(NULL, root, &key, &path, 0, 0);
-       if (ret) {
+       if (ret < 0) {
                err |= REFERENCER_MISSING;
                goto release_out;
        }
@@ -9948,6 +9949,8 @@ static int traverse_tree_block(struct btrfs_root *root,
                                struct extent_buffer *node)
 {
        struct extent_buffer *eb;
+       struct btrfs_key key;
+       struct btrfs_key drop_key;
        int level;
        u64 nr;
        int i;
@@ -9993,6 +9996,7 @@ static int traverse_tree_block(struct btrfs_root *root,
        }
 
        nr = btrfs_header_nritems(node);
+       btrfs_disk_key_to_cpu(&drop_key, &root->root_item.drop_progress);
        btree_space_waste += (BTRFS_NODEPTRS_PER_BLOCK(root) - nr) *
                sizeof(struct btrfs_key_ptr);
 
@@ -10000,6 +10004,11 @@ static int traverse_tree_block(struct btrfs_root *root,
        for (i = 0; i < nr; i++) {
                u64 blocknr = btrfs_node_blockptr(node, i);
 
+               btrfs_node_key_to_cpu(node, &key, i);
+               if (level == root->root_item.drop_level &&
+                   is_dropped_key(&key, &drop_key))
+                       continue;
+
                /*
                 * As a btrfs tree has most 8 levels (0..7), so it's quite safe
                 * to call the function itself.