From d278850eff3053ef166cf64c16f798dfe36278a2 Mon Sep 17 00:00:00 2001 From: Josef Bacik Date: Fri, 29 Sep 2017 15:43:57 -0400 Subject: btrfs: remove delayed_ref_node from ref_head This is just excessive information in the ref_head, and makes the code complicated. It is a relic from when we had the heads and the refs in the same tree, which is no longer the case. With this removal I've cleaned up a bunch of the cruft around this old assumption as well. Signed-off-by: Josef Bacik Reviewed-by: David Sterba Signed-off-by: David Sterba --- fs/btrfs/delayed-ref.h | 49 +++++++++++++++++-------------------------------- 1 file changed, 17 insertions(+), 32 deletions(-) (limited to 'fs/btrfs/delayed-ref.h') diff --git a/fs/btrfs/delayed-ref.h b/fs/btrfs/delayed-ref.h index ce88e4ac5276..1ce11858d727 100644 --- a/fs/btrfs/delayed-ref.h +++ b/fs/btrfs/delayed-ref.h @@ -26,15 +26,6 @@ #define BTRFS_ADD_DELAYED_EXTENT 3 /* record a full extent allocation */ #define BTRFS_UPDATE_DELAYED_HEAD 4 /* not changing ref count on head ref */ -/* - * XXX: Qu: I really hate the design that ref_head and tree/data ref shares the - * same ref_node structure. - * Ref_head is in a higher logic level than tree/data ref, and duplicated - * bytenr/num_bytes in ref_node is really a waste or memory, they should be - * referred from ref_head. - * This gets more disgusting after we use list to store tree/data ref in - * ref_head. Must clean this mess up later. - */ struct btrfs_delayed_ref_node { /*data/tree ref use list, stored in ref_head->ref_list. */ struct list_head list; @@ -91,8 +82,9 @@ struct btrfs_delayed_extent_op { * reference count modifications we've queued up. */ struct btrfs_delayed_ref_head { - struct btrfs_delayed_ref_node node; - + u64 bytenr; + u64 num_bytes; + refcount_t refs; /* * the mutex is held while running the refs, and it is also * held when checking the sum of reference modifications. @@ -115,6 +107,14 @@ struct btrfs_delayed_ref_head { */ int total_ref_mod; + /* + * This is the current outstanding mod references for this bytenr. This + * is used with lookup_extent_info to get an accurate reference count + * for a bytenr, so it is adjusted as delayed refs are run so that any + * on disk reference count + ref_mod is accurate. + */ + int ref_mod; + /* * For qgroup reserved space freeing. * @@ -234,15 +234,18 @@ static inline void btrfs_put_delayed_ref(struct btrfs_delayed_ref_node *ref) case BTRFS_SHARED_DATA_REF_KEY: kmem_cache_free(btrfs_delayed_data_ref_cachep, ref); break; - case 0: - kmem_cache_free(btrfs_delayed_ref_head_cachep, ref); - break; default: BUG(); } } } +static inline void btrfs_put_delayed_ref_head(struct btrfs_delayed_ref_head *head) +{ + if (refcount_dec_and_test(&head->refs)) + kmem_cache_free(btrfs_delayed_ref_head_cachep, head); +} + int btrfs_add_delayed_tree_ref(struct btrfs_fs_info *fs_info, struct btrfs_trans_handle *trans, u64 bytenr, u64 num_bytes, u64 parent, @@ -282,36 +285,18 @@ int btrfs_check_delayed_seq(struct btrfs_fs_info *fs_info, struct btrfs_delayed_ref_root *delayed_refs, u64 seq); -/* - * a node might live in a head or a regular ref, this lets you - * test for the proper type to use. - */ -static int btrfs_delayed_ref_is_head(struct btrfs_delayed_ref_node *node) -{ - return node->is_head; -} - /* * helper functions to cast a node into its container */ static inline struct btrfs_delayed_tree_ref * btrfs_delayed_node_to_tree_ref(struct btrfs_delayed_ref_node *node) { - WARN_ON(btrfs_delayed_ref_is_head(node)); return container_of(node, struct btrfs_delayed_tree_ref, node); } static inline struct btrfs_delayed_data_ref * btrfs_delayed_node_to_data_ref(struct btrfs_delayed_ref_node *node) { - WARN_ON(btrfs_delayed_ref_is_head(node)); return container_of(node, struct btrfs_delayed_data_ref, node); } - -static inline struct btrfs_delayed_ref_head * -btrfs_delayed_node_to_head(struct btrfs_delayed_ref_node *node) -{ - WARN_ON(!btrfs_delayed_ref_is_head(node)); - return container_of(node, struct btrfs_delayed_ref_head, node); -} #endif -- cgit v1.2.3