[PATCH 24/40] btrfs: Rename remove_backref_node() to btrfs_backref_cleanup_node() and move it to backref.c

Qu Wenruo
2020-03-23T10:25:40Z

Also add comment explaining the cleanup progress, to differ it from
btrfs_backref_drop_node().

Signed-off-by: Qu Wenruo <wqu@suse.com>
---
fs/btrfs/backref.c | 38 ++++++++++++++++++++++++++++++++
fs/btrfs/backref.h | 9 ++++++++
fs/btrfs/relocation.c | 51 ++++---------------------------------------
3 files changed, 51 insertions(+), 47 deletions(-)

diff --git a/fs/btrfs/backref.c b/fs/btrfs/backref.c
index 2bf3bf2d7b85..0c8950750682 100644
--- a/fs/btrfs/backref.c
+++ b/fs/btrfs/backref.c
@@ -2515,3 +2515,41 @@ struct btrfs_backref_edge *btrfs_backref_alloc_edge(
cache->nr_edges++;
return edge;
}
+
+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);
+}
diff --git a/fs/btrfs/backref.h b/fs/btrfs/backref.h
index a6d568449c88..068a28c8e37b 100644
--- a/fs/btrfs/backref.h
+++ b/fs/btrfs/backref.h
@@ -349,4 +349,13 @@ static inline void btrfs_backref_drop_node(struct btrfs_backref_cache *tree,
btrfs_backref_free_node(tree, node);
}

+/*
+ * 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 detached node.
+ */
+void btrfs_backref_cleanup_node(struct btrfs_backref_cache *cache,
+ struct btrfs_backref_node *node);
#endif
diff --git a/fs/btrfs/relocation.c b/fs/btrfs/relocation.c
index 47649ff1052f..4c687318f70b 100644
--- a/fs/btrfs/relocation.c
+++ b/fs/btrfs/relocation.c
@@ -160,9 +160,6 @@ struct reloc_control {
#define MOVE_DATA_EXTENTS 0
#define UPDATE_DATA_PTRS 1

-static void remove_backref_node(struct btrfs_backref_cache *cache,
- struct btrfs_backref_node *node);
-
static void mark_block_processed(struct reloc_control *rc,
struct btrfs_backref_node *node)
{
@@ -193,13 +190,13 @@ static void backref_cache_cleanup(struct btrfs_backref_cache *cache)
while (!list_empty(&cache->detached)) {
node = list_entry(cache->detached.next,
struct btrfs_backref_node, list);
- remove_backref_node(cache, node);
+ btrfs_backref_cleanup_node(cache, node);
}

while (!list_empty(&cache->leaves)) {
node = list_entry(cache->leaves.next,
struct btrfs_backref_node, lower);
- remove_backref_node(cache, node);
+ btrfs_backref_cleanup_node(cache, node);
}

cache->last_trans = 0;
@@ -275,46 +272,6 @@ static struct btrfs_backref_node *walk_down_backref(
*index = 0;
return NULL;
}
-/*
- * remove a backref node from the backref cache
- */
-static void remove_backref_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);
-}

static void update_backref_node(struct btrfs_backref_cache *cache,
struct btrfs_backref_node *node, u64 bytenr)
@@ -352,7 +309,7 @@ static int update_backref_cache(struct btrfs_trans_handle *trans,
while (!list_empty(&cache->detached)) {
node = list_entry(cache->detached.next,
struct btrfs_backref_node, list);
- remove_backref_node(cache, node);
+ btrfs_backref_cleanup_node(cache, node);
}

while (!list_empty(&cache->changed)) {
@@ -3038,7 +2995,7 @@ static int relocate_tree_block(struct btrfs_trans_handle *trans,
}
out:
if (ret || node->level == 0 || node->cowonly)
- remove_backref_node(&rc->backref_cache, node);
+ btrfs_backref_cleanup_node(&rc->backref_cache, node);
return ret;
}

--
2.25.2