diff options
Diffstat (limited to 'fs/btrfs/ctree.c')
| -rw-r--r-- | fs/btrfs/ctree.c | 31 |
1 files changed, 23 insertions, 8 deletions
diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c index 0639a555e16e..74c03fb0ca1d 100644 --- a/fs/btrfs/ctree.c +++ b/fs/btrfs/ctree.c @@ -156,10 +156,23 @@ struct extent_buffer *btrfs_root_node(struct btrfs_root *root) { struct extent_buffer *eb; - rcu_read_lock(); - eb = rcu_dereference(root->node); - extent_buffer_get(eb); - rcu_read_unlock(); + while (1) { + rcu_read_lock(); + eb = rcu_dereference(root->node); + + /* + * RCU really hurts here, we could free up the root node because + * it was cow'ed but we may not get the new root node yet so do + * the inc_not_zero dance and if it doesn't work then + * synchronize_rcu and try again. + */ + if (atomic_inc_not_zero(&eb->refs)) { + rcu_read_unlock(); + break; + } + rcu_read_unlock(); + synchronize_rcu(); + } return eb; } @@ -504,7 +517,7 @@ static noinline int __btrfs_cow_block(struct btrfs_trans_handle *trans, } if (unlock_orig) btrfs_tree_unlock(buf); - free_extent_buffer(buf); + free_extent_buffer_stale(buf); btrfs_mark_buffer_dirty(cow); *cow_ret = cow; return 0; @@ -959,7 +972,7 @@ static noinline int balance_level(struct btrfs_trans_handle *trans, root_sub_used(root, mid->len); btrfs_free_tree_block(trans, root, mid, 0, 1, 0); /* once for the root ptr */ - free_extent_buffer(mid); + free_extent_buffer_stale(mid); return 0; } if (btrfs_header_nritems(mid) > @@ -1016,7 +1029,7 @@ static noinline int balance_level(struct btrfs_trans_handle *trans, ret = wret; root_sub_used(root, right->len); btrfs_free_tree_block(trans, root, right, 0, 1, 0); - free_extent_buffer(right); + free_extent_buffer_stale(right); right = NULL; } else { struct btrfs_disk_key right_key; @@ -1056,7 +1069,7 @@ static noinline int balance_level(struct btrfs_trans_handle *trans, ret = wret; root_sub_used(root, mid->len); btrfs_free_tree_block(trans, root, mid, 0, 1, 0); - free_extent_buffer(mid); + free_extent_buffer_stale(mid); mid = NULL; } else { /* update the parent key to reflect our changes */ @@ -3781,7 +3794,9 @@ static noinline int btrfs_del_leaf(struct btrfs_trans_handle *trans, root_sub_used(root, leaf->len); + extent_buffer_get(leaf); btrfs_free_tree_block(trans, root, leaf, 0, 1, 0); + free_extent_buffer_stale(leaf); return 0; } /* |