From 023acb07bc996636b39c70e07966f70e70c0a008 Mon Sep 17 00:00:00 2001 From: Qu Wenruo Date: Mon, 23 Mar 2020 15:42:25 +0800 Subject: btrfs: backref: rename and move remove_backref_node() Also add comment explaining the cleanup progress, to differ it from btrfs_backref_drop_node(). Signed-off-by: Qu Wenruo Reviewed-by: David Sterba Signed-off-by: David Sterba --- fs/btrfs/backref.c | 45 +++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 45 insertions(+) (limited to 'fs/btrfs/backref.c') diff --git a/fs/btrfs/backref.c b/fs/btrfs/backref.c index 4837dcf06ba4..daac20c1a417 100644 --- a/fs/btrfs/backref.c +++ b/fs/btrfs/backref.c @@ -2514,3 +2514,48 @@ struct btrfs_backref_edge *btrfs_backref_alloc_edge( cache->nr_edges++; return edge; } + +/* + * Drop the backref node from cache, also cleaning up all its + * upper edges and any uncached nodes in the path. + * + * This cleanup happens bottom up, thus the node should either + * be the lowest node in the cache or a detached node. + */ +void btrfs_backref_cleanup_node(struct btrfs_backref_cache *cache, + struct btrfs_backref_node *node) +{ + struct btrfs_backref_node *upper; + struct btrfs_backref_edge *edge; + + if (!node) + return; + + BUG_ON(!node->lowest && !node->detached); + while (!list_empty(&node->upper)) { + edge = list_entry(node->upper.next, struct btrfs_backref_edge, + list[LOWER]); + upper = edge->node[UPPER]; + list_del(&edge->list[LOWER]); + list_del(&edge->list[UPPER]); + btrfs_backref_free_edge(cache, edge); + + if (RB_EMPTY_NODE(&upper->rb_node)) { + BUG_ON(!list_empty(&node->upper)); + btrfs_backref_drop_node(cache, node); + node = upper; + node->lowest = 1; + continue; + } + /* + * Add the node to leaf node list if no other child block + * cached. + */ + if (list_empty(&upper->lower)) { + list_add_tail(&upper->lower, &cache->leaves); + upper->lowest = 1; + } + } + + btrfs_backref_drop_node(cache, node); +} -- cgit v1.2.3