diff options
| -rw-r--r-- | fs/btrfs/delayed-ref.c | 34 | ||||
| -rw-r--r-- | fs/btrfs/delayed-ref.h | 70 | ||||
| -rw-r--r-- | fs/btrfs/transaction.c | 4 |
3 files changed, 108 insertions, 0 deletions
diff --git a/fs/btrfs/delayed-ref.c b/fs/btrfs/delayed-ref.c index babd37b..a405db0 100644 --- a/fs/btrfs/delayed-ref.c +++ b/fs/btrfs/delayed-ref.c @@ -101,6 +101,11 @@ static int comp_entry(struct btrfs_delayed_ref_node *ref2, return -1; if (ref1->type > ref2->type) return 1; + /* merging of sequenced refs is not allowed */ + if (ref1->seq < ref2->seq) + return -1; + if (ref1->seq > ref2->seq) + return 1; if (ref1->type == BTRFS_TREE_BLOCK_REF_KEY || ref1->type == BTRFS_SHARED_BLOCK_REF_KEY) { return comp_tree_refs(btrfs_delayed_node_to_tree_ref(ref2), @@ -209,6 +214,24 @@ int btrfs_delayed_ref_lock(struct btrfs_trans_handle *trans, return 0; } +int btrfs_check_delayed_seq(struct btrfs_delayed_ref_root *delayed_refs, + u64 seq) +{ + struct seq_list *elem; + + assert_spin_locked(&delayed_refs->lock); + if (list_empty(&delayed_refs->seq_head)) + return 0; + + elem = list_first_entry(&delayed_refs->seq_head, struct seq_list, list); + if (seq >= elem->seq) { + pr_debug("holding back delayed_ref %llu, lowest is %llu (%p)\n", + seq, elem->seq, delayed_refs); + return 1; + } + return 0; +} + int btrfs_find_ref_cluster(struct btrfs_trans_handle *trans, struct list_head *cluster, u64 start) { @@ -438,6 +461,7 @@ static noinline int add_delayed_ref_head(struct btrfs_fs_info *fs_info, ref->action = 0; ref->is_head = 1; ref->in_tree = 1; + ref->seq = 0; head_ref = btrfs_delayed_node_to_head(ref); head_ref->must_insert_reserved = must_insert_reserved; @@ -479,6 +503,7 @@ static noinline int add_delayed_tree_ref(struct btrfs_fs_info *fs_info, struct btrfs_delayed_ref_node *existing; struct btrfs_delayed_tree_ref *full_ref; struct btrfs_delayed_ref_root *delayed_refs; + u64 seq = 0; if (action == BTRFS_ADD_DELAYED_EXTENT) action = BTRFS_ADD_DELAYED_REF; @@ -494,6 +519,10 @@ static noinline int add_delayed_tree_ref(struct btrfs_fs_info *fs_info, ref->is_head = 0; ref->in_tree = 1; + if (need_ref_seq(for_cow, ref_root)) + seq = inc_delayed_seq(delayed_refs); + ref->seq = seq; + full_ref = btrfs_delayed_node_to_tree_ref(ref); full_ref->parent = parent; full_ref->root = ref_root; @@ -534,6 +563,7 @@ static noinline int add_delayed_data_ref(struct btrfs_fs_info *fs_info, struct btrfs_delayed_ref_node *existing; struct btrfs_delayed_data_ref *full_ref; struct btrfs_delayed_ref_root *delayed_refs; + u64 seq = 0; if (action == BTRFS_ADD_DELAYED_EXTENT) action = BTRFS_ADD_DELAYED_REF; @@ -549,6 +579,10 @@ static noinline int add_delayed_data_ref(struct btrfs_fs_info *fs_info, ref->is_head = 0; ref->in_tree = 1; + if (need_ref_seq(for_cow, ref_root)) + seq = inc_delayed_seq(delayed_refs); + ref->seq = seq; + full_ref = btrfs_delayed_node_to_data_ref(ref); full_ref->parent = parent; full_ref->root = ref_root; diff --git a/fs/btrfs/delayed-ref.h b/fs/btrfs/delayed-ref.h index a5fb2bc..174416f 100644 --- a/fs/btrfs/delayed-ref.h +++ b/fs/btrfs/delayed-ref.h @@ -33,6 +33,9 @@ struct btrfs_delayed_ref_node { /* the size of the extent */ u64 num_bytes; + /* seq number to keep track of insertion order */ + u64 seq; + /* ref count on this data structure */ atomic_t refs; @@ -136,6 +139,20 @@ struct btrfs_delayed_ref_root { int flushing; u64 run_delayed_start; + + /* + * seq number of delayed refs. We need to know if a backref was being + * added before the currently processed ref or afterwards. + */ + u64 seq; + + /* + * seq_list holds a list of all seq numbers that are currently being + * added to the list. While walking backrefs (btrfs_find_all_roots, + * qgroups), which might take some time, no newer ref must be processed, + * as it might influence the outcome of the walk. + */ + struct list_head seq_head; }; static inline void btrfs_put_delayed_ref(struct btrfs_delayed_ref_node *ref) @@ -171,6 +188,59 @@ int btrfs_delayed_ref_lock(struct btrfs_trans_handle *trans, struct btrfs_delayed_ref_head *head); int btrfs_find_ref_cluster(struct btrfs_trans_handle *trans, struct list_head *cluster, u64 search_start); + +struct seq_list { + struct list_head list; + u64 seq; +}; + +static inline u64 inc_delayed_seq(struct btrfs_delayed_ref_root *delayed_refs) +{ + assert_spin_locked(&delayed_refs->lock); + ++delayed_refs->seq; + return delayed_refs->seq; +} + +static inline void +btrfs_get_delayed_seq(struct btrfs_delayed_ref_root *delayed_refs, + struct seq_list *elem) +{ + assert_spin_locked(&delayed_refs->lock); + elem->seq = delayed_refs->seq; + list_add_tail(&elem->list, &delayed_refs->seq_head); +} + +static inline void +btrfs_put_delayed_seq(struct btrfs_delayed_ref_root *delayed_refs, + struct seq_list *elem) +{ + spin_lock(&delayed_refs->lock); + list_del(&elem->list); + spin_unlock(&delayed_refs->lock); +} + +int btrfs_check_delayed_seq(struct btrfs_delayed_ref_root *delayed_refs, + u64 seq); + +/* + * delayed refs with a ref_seq > 0 must be held back during backref walking. + * this only applies to items in one of the fs-trees. for_cow items never need + * to be held back, so they won't get a ref_seq number. + */ +static inline int need_ref_seq(int for_cow, u64 rootid) +{ + if (for_cow) + return 0; + + if (rootid == BTRFS_FS_TREE_OBJECTID) + return 1; + + if ((s64)rootid >= (s64)BTRFS_FIRST_FREE_OBJECTID) + return 1; + + return 0; +} + /* * a node might live in a head or a regular ref, this lets you * test for the proper type to use. diff --git a/fs/btrfs/transaction.c b/fs/btrfs/transaction.c index a2bfedc..31a7393 100644 --- a/fs/btrfs/transaction.c +++ b/fs/btrfs/transaction.c @@ -36,6 +36,8 @@ static noinline void put_transaction(struct btrfs_transaction *transaction) WARN_ON(atomic_read(&transaction->use_count) == 0); if (atomic_dec_and_test(&transaction->use_count)) { BUG_ON(!list_empty(&transaction->list)); + WARN_ON(transaction->delayed_refs.root.rb_node); + WARN_ON(!list_empty(&transaction->delayed_refs.seq_head)); memset(transaction, 0, sizeof(*transaction)); kmem_cache_free(btrfs_transaction_cachep, transaction); } @@ -108,8 +110,10 @@ loop: cur_trans->delayed_refs.num_heads = 0; cur_trans->delayed_refs.flushing = 0; cur_trans->delayed_refs.run_delayed_start = 0; + cur_trans->delayed_refs.seq = 1; spin_lock_init(&cur_trans->commit_lock); spin_lock_init(&cur_trans->delayed_refs.lock); + INIT_LIST_HEAD(&cur_trans->delayed_refs.seq_head); INIT_LIST_HEAD(&cur_trans->pending_snapshots); list_add_tail(&cur_trans->list, &root->fs_info->trans_list); |