From c6fc24549960f26910cd0c6e4b5f48f2f306b11d Mon Sep 17 00:00:00 2001 From: Qu Wenruo Date: Mon, 30 Mar 2015 17:03:00 +0800 Subject: btrfs: delayed-ref: Use list to replace the ref_root in ref_head. This patch replace the rbtree used in ref_head to list. This has the following advantage: 1) Easier merge logic. With the new list implement, we only need to care merging the tail ref_node with the new ref_node. And this can be done quite easy at insert time, no need to do a indicated merge at run_delayed_refs(). Signed-off-by: Qu Wenruo Signed-off-by: Chris Mason --- fs/btrfs/extent-tree.c | 46 +++++++++------------------------------------- 1 file changed, 9 insertions(+), 37 deletions(-) (limited to 'fs/btrfs/extent-tree.c') diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c index 4eefabcc838f..adf0eedde502 100644 --- a/fs/btrfs/extent-tree.c +++ b/fs/btrfs/extent-tree.c @@ -2323,28 +2323,14 @@ static int run_one_delayed_ref(struct btrfs_trans_handle *trans, return ret; } -static noinline struct btrfs_delayed_ref_node * +static inline struct btrfs_delayed_ref_node * select_delayed_ref(struct btrfs_delayed_ref_head *head) { - struct rb_node *node; - struct btrfs_delayed_ref_node *ref, *last = NULL;; + if (list_empty(&head->ref_list)) + return NULL; - /* - * select delayed ref of type BTRFS_ADD_DELAYED_REF first. - * this prevents ref count from going down to zero when - * there still are pending delayed ref. - */ - node = rb_first(&head->ref_root); - while (node) { - ref = rb_entry(node, struct btrfs_delayed_ref_node, - rb_node); - if (ref->action == BTRFS_ADD_DELAYED_REF) - return ref; - else if (last == NULL) - last = ref; - node = rb_next(node); - } - return last; + return list_entry(head->ref_list.next, struct btrfs_delayed_ref_node, + list); } /* @@ -2396,16 +2382,7 @@ static noinline int __btrfs_run_delayed_refs(struct btrfs_trans_handle *trans, } } - /* - * We need to try and merge add/drops of the same ref since we - * can run into issues with relocate dropping the implicit ref - * and then it being added back again before the drop can - * finish. If we merged anything we need to re-loop so we can - * get a good ref. - */ spin_lock(&locked_ref->lock); - btrfs_merge_delayed_refs(trans, fs_info, delayed_refs, - locked_ref); /* * locked_ref is the head node, so we have to go one @@ -2482,7 +2459,7 @@ static noinline int __btrfs_run_delayed_refs(struct btrfs_trans_handle *trans, spin_unlock(&locked_ref->lock); spin_lock(&delayed_refs->lock); spin_lock(&locked_ref->lock); - if (rb_first(&locked_ref->ref_root) || + if (!list_empty(&locked_ref->ref_list) || locked_ref->extent_op) { spin_unlock(&locked_ref->lock); spin_unlock(&delayed_refs->lock); @@ -2496,7 +2473,7 @@ static noinline int __btrfs_run_delayed_refs(struct btrfs_trans_handle *trans, } else { actual_count++; ref->in_tree = 0; - rb_erase(&ref->rb_node, &locked_ref->ref_root); + list_del(&ref->list); } atomic_dec(&delayed_refs->num_entries); @@ -2905,7 +2882,6 @@ static noinline int check_delayed_ref(struct btrfs_trans_handle *trans, struct btrfs_delayed_ref_node *ref; struct btrfs_delayed_data_ref *data_ref; struct btrfs_delayed_ref_root *delayed_refs; - struct rb_node *node; int ret = 0; delayed_refs = &trans->transaction->delayed_refs; @@ -2934,11 +2910,7 @@ static noinline int check_delayed_ref(struct btrfs_trans_handle *trans, spin_unlock(&delayed_refs->lock); spin_lock(&head->lock); - node = rb_first(&head->ref_root); - while (node) { - ref = rb_entry(node, struct btrfs_delayed_ref_node, rb_node); - node = rb_next(node); - + list_for_each_entry(ref, &head->ref_list, list) { /* If it's a shared ref we know a cross reference exists */ if (ref->type != BTRFS_EXTENT_DATA_REF_KEY) { ret = 1; @@ -6448,7 +6420,7 @@ static noinline int check_ref_cleanup(struct btrfs_trans_handle *trans, goto out_delayed_unlock; spin_lock(&head->lock); - if (rb_first(&head->ref_root)) + if (!list_empty(&head->ref_list)) goto out; if (head->extent_op) { -- cgit v1.2.3