diff options
| -rw-r--r-- | fs/btrfs/delayed-ref.c | 8 | ||||
| -rw-r--r-- | fs/btrfs/delayed-ref.h | 7 | ||||
| -rw-r--r-- | fs/btrfs/extent-tree.c | 59 | ||||
| -rw-r--r-- | fs/btrfs/transaction.c | 1 |
4 files changed, 74 insertions, 1 deletions
diff --git a/fs/btrfs/delayed-ref.c b/fs/btrfs/delayed-ref.c index ee181989d444..66e4f29505a3 100644 --- a/fs/btrfs/delayed-ref.c +++ b/fs/btrfs/delayed-ref.c @@ -664,6 +664,9 @@ int btrfs_add_delayed_tree_ref(struct btrfs_fs_info *fs_info, num_bytes, parent, ref_root, level, action, for_cow); BUG_ON(ret); + if (!need_ref_seq(for_cow, ref_root) && + waitqueue_active(&delayed_refs->seq_wait)) + wake_up(&delayed_refs->seq_wait); spin_unlock(&delayed_refs->lock); return 0; } @@ -712,6 +715,9 @@ int btrfs_add_delayed_data_ref(struct btrfs_fs_info *fs_info, num_bytes, parent, ref_root, owner, offset, action, for_cow); BUG_ON(ret); + if (!need_ref_seq(for_cow, ref_root) && + waitqueue_active(&delayed_refs->seq_wait)) + wake_up(&delayed_refs->seq_wait); spin_unlock(&delayed_refs->lock); return 0; } @@ -739,6 +745,8 @@ int btrfs_add_delayed_extent_op(struct btrfs_fs_info *fs_info, extent_op->is_data); BUG_ON(ret); + if (waitqueue_active(&delayed_refs->seq_wait)) + wake_up(&delayed_refs->seq_wait); spin_unlock(&delayed_refs->lock); return 0; } diff --git a/fs/btrfs/delayed-ref.h b/fs/btrfs/delayed-ref.h index 174416f7882b..d8f244d94925 100644 --- a/fs/btrfs/delayed-ref.h +++ b/fs/btrfs/delayed-ref.h @@ -153,6 +153,12 @@ struct btrfs_delayed_ref_root { * as it might influence the outcome of the walk. */ struct list_head seq_head; + + /* + * when the only refs we have in the list must not be processed, we want + * to wait for more refs to show up or for the end of backref walking. + */ + wait_queue_head_t seq_wait; }; static inline void btrfs_put_delayed_ref(struct btrfs_delayed_ref_node *ref) @@ -216,6 +222,7 @@ btrfs_put_delayed_seq(struct btrfs_delayed_ref_root *delayed_refs, { spin_lock(&delayed_refs->lock); list_del(&elem->list); + wake_up(&delayed_refs->seq_wait); spin_unlock(&delayed_refs->lock); } diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c index bbcca12fbbba..0a435e2e143e 100644 --- a/fs/btrfs/extent-tree.c +++ b/fs/btrfs/extent-tree.c @@ -2300,7 +2300,12 @@ static noinline int run_clustered_refs(struct btrfs_trans_handle *trans, ref->in_tree = 0; rb_erase(&ref->rb_node, &delayed_refs->root); delayed_refs->num_entries--; - + /* + * we modified num_entries, but as we're currently running + * delayed refs, skip + * wake_up(&delayed_refs->seq_wait); + * here. + */ spin_unlock(&delayed_refs->lock); ret = run_one_delayed_ref(trans, root, ref, extent_op, @@ -2317,6 +2322,23 @@ static noinline int run_clustered_refs(struct btrfs_trans_handle *trans, return count; } + +static void wait_for_more_refs(struct btrfs_delayed_ref_root *delayed_refs, + unsigned long num_refs) +{ + struct list_head *first_seq = delayed_refs->seq_head.next; + + spin_unlock(&delayed_refs->lock); + pr_debug("waiting for more refs (num %ld, first %p)\n", + num_refs, first_seq); + wait_event(delayed_refs->seq_wait, + num_refs != delayed_refs->num_entries || + delayed_refs->seq_head.next != first_seq); + pr_debug("done waiting for more refs (num %ld, first %p)\n", + delayed_refs->num_entries, delayed_refs->seq_head.next); + spin_lock(&delayed_refs->lock); +} + /* * this starts processing the delayed reference count updates and * extent insertions we have queued up so far. count can be @@ -2332,8 +2354,11 @@ int btrfs_run_delayed_refs(struct btrfs_trans_handle *trans, struct btrfs_delayed_ref_node *ref; struct list_head cluster; int ret; + u64 delayed_start; int run_all = count == (unsigned long)-1; int run_most = 0; + unsigned long num_refs = 0; + int consider_waiting; if (root == root->fs_info->extent_root) root = root->fs_info->tree_root; @@ -2341,6 +2366,7 @@ int btrfs_run_delayed_refs(struct btrfs_trans_handle *trans, delayed_refs = &trans->transaction->delayed_refs; INIT_LIST_HEAD(&cluster); again: + consider_waiting = 0; spin_lock(&delayed_refs->lock); if (count == 0) { count = delayed_refs->num_entries * 2; @@ -2357,11 +2383,35 @@ again: * of refs to process starting at the first one we are able to * lock */ + delayed_start = delayed_refs->run_delayed_start; ret = btrfs_find_ref_cluster(trans, &cluster, delayed_refs->run_delayed_start); if (ret) break; + if (delayed_start >= delayed_refs->run_delayed_start) { + if (consider_waiting == 0) { + /* + * btrfs_find_ref_cluster looped. let's do one + * more cycle. if we don't run any delayed ref + * during that cycle (because we can't because + * all of them are blocked) and if the number of + * refs doesn't change, we avoid busy waiting. + */ + consider_waiting = 1; + num_refs = delayed_refs->num_entries; + } else { + wait_for_more_refs(delayed_refs, num_refs); + /* + * after waiting, things have changed. we + * dropped the lock and someone else might have + * run some refs, built new clusters and so on. + * therefore, we restart staleness detection. + */ + consider_waiting = 0; + } + } + ret = run_clustered_refs(trans, root, &cluster); BUG_ON(ret < 0); @@ -2369,6 +2419,11 @@ again: if (count == 0) break; + + if (ret || delayed_refs->run_delayed_start == 0) { + /* refs were run, let's reset staleness detection */ + consider_waiting = 0; + } } if (run_all) { @@ -4933,6 +4988,8 @@ static noinline int check_ref_cleanup(struct btrfs_trans_handle *trans, rb_erase(&head->node.rb_node, &delayed_refs->root); delayed_refs->num_entries--; + if (waitqueue_active(&delayed_refs->seq_wait)) + wake_up(&delayed_refs->seq_wait); /* * we don't take a ref on the node because we're removing it from the diff --git a/fs/btrfs/transaction.c b/fs/btrfs/transaction.c index 31a7393af64e..04c5c7c2c32f 100644 --- a/fs/btrfs/transaction.c +++ b/fs/btrfs/transaction.c @@ -111,6 +111,7 @@ loop: cur_trans->delayed_refs.flushing = 0; cur_trans->delayed_refs.run_delayed_start = 0; cur_trans->delayed_refs.seq = 1; + init_waitqueue_head(&cur_trans->delayed_refs.seq_wait); spin_lock_init(&cur_trans->commit_lock); spin_lock_init(&cur_trans->delayed_refs.lock); INIT_LIST_HEAD(&cur_trans->delayed_refs.seq_head); |