To resolve backrefs, ROOT_REPLACE operations in the tree mod log are required to be tied to at least one KEY_REMOVE_WHILE_FREEING operation. Therefore, those operations must be enclosed by tree_mod_log_write_lock() and tree_mod_log_write_unlock() calls.
Those calls are private to the tree_mod_log_* functions, which means that removal of the elements of an old root node must be logged from tree_mod_log_insert_root. This partly reverts and corrects commit ba1bfbd5 (Btrfs: fix a tree mod logging issue for root replacement operations). This fixes the brand-new version of xfstest 276 as of commit cfe73f71. Signed-off-by: Jan Schmidt <[email protected]> --- Has probably been Reported-by: Alex Lyakas <[email protected]> (unconfirmed). fs/btrfs/ctree.c | 30 ++++++++++++++++++++---------- 1 files changed, 20 insertions(+), 10 deletions(-) diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c index aa50952..9dfc74a 100644 --- a/fs/btrfs/ctree.c +++ b/fs/btrfs/ctree.c @@ -763,6 +763,8 @@ pr_debug("MLL: tree mod seq list %p empty\n", &fs_info->tree_mod_seq_list); return 0; } + __tree_mod_log_free_eb(fs_info, old_root); + ret = tree_mod_alloc(fs_info, flags, &tm); if (ret < 0) goto out; @@ -859,7 +861,7 @@ tree_mod_log_search(struct btrfs_fs_info *fs_info, u64 start, u64 min_seq) static noinline void tree_mod_log_eb_copy(struct btrfs_fs_info *fs_info, struct extent_buffer *dst, struct extent_buffer *src, unsigned long dst_offset, - unsigned long src_offset, int nr_items) + unsigned long src_offset, int nr_items, int log_removal) { int ret; int i; @@ -873,10 +875,12 @@ tree_mod_log_eb_copy(struct btrfs_fs_info *fs_info, struct extent_buffer *dst, } for (i = 0; i < nr_items; i++) { - ret = tree_mod_log_insert_key_locked(fs_info, src, - i + src_offset, - MOD_LOG_KEY_REMOVE); - BUG_ON(ret < 0); + if (log_removal) { + ret = tree_mod_log_insert_key_locked(fs_info, src, + i + src_offset, + MOD_LOG_KEY_REMOVE); + BUG_ON(ret < 0); + } ret = tree_mod_log_insert_key_locked(fs_info, dst, i + dst_offset, MOD_LOG_KEY_ADD); @@ -1050,7 +1054,6 @@ static noinline int update_ref_for_cow(struct btrfs_trans_handle *trans, ret = btrfs_dec_ref(trans, root, buf, 1, 1); BUG_ON(ret); /* -ENOMEM */ } - tree_mod_log_free_eb(root->fs_info, buf); clean_tree_block(trans, root, buf); *last_ref = 1; } @@ -1171,6 +1174,7 @@ DONE_mod_log("setting a new root: %llu -> %llu\n", root->node->start, cow->start btrfs_set_node_ptr_generation(parent, parent_slot, trans->transid); btrfs_mark_buffer_dirty(parent); + tree_mod_log_free_eb(root->fs_info, buf); btrfs_free_tree_block(trans, root, buf, parent_start, last_ref); } @@ -1901,7 +1905,6 @@ DONE_mod_log("promoting %llu as replacement root for almost empty %llu, tree dep } DONE_mod_log("new root is %llu\n", child->start); - tree_mod_log_free_eb(root->fs_info, root->node); tree_mod_log_set_root_pointer(root, child); rcu_assign_pointer(root->node, child); @@ -3210,7 +3213,7 @@ static int push_node_left(struct btrfs_trans_handle *trans, push_items = min(src_nritems - 8, push_items); tree_mod_log_eb_copy(root->fs_info, dst, src, dst_nritems, 0, - push_items); + push_items, 1); copy_extent_buffer(dst, src, btrfs_node_key_ptr_offset(dst_nritems), btrfs_node_key_ptr_offset(0), @@ -3283,7 +3286,7 @@ static int balance_node_right(struct btrfs_trans_handle *trans, DONE_mod_log("pushing %d items from %llu (now has %d) to %llu (now has %d)\n", push_items, src->start, src_nritems - push_items, dst->start, dst_nritems + push_items); tree_mod_log_eb_copy(root->fs_info, dst, src, 0, - src_nritems - push_items, push_items); + src_nritems - push_items, push_items, 1); copy_extent_buffer(dst, src, btrfs_node_key_ptr_offset(0), btrfs_node_key_ptr_offset(src_nritems - push_items), @@ -3436,6 +3439,7 @@ static noinline int split_node(struct btrfs_trans_handle *trans, int mid; int ret; u32 c_nritems; + int tree_mod_log_removal = 1; c = path->nodes[level]; DONE_mod_log("%llu\n", c->start); @@ -3443,6 +3447,11 @@ DONE_mod_log("%llu\n", c->start); if (c == root->node) { /* trying to split the root, lets make a new one */ ret = insert_new_root(trans, root, path, level + 1); + /* + * removal of root nodes has been logged by + * tree_mod_log_set_root_pointer due to locking + */ + tree_mod_log_removal = 0; if (ret) return ret; } else { @@ -3481,7 +3490,8 @@ DONE_mod_log("buffer %llu, middle key (%llu %u %llu), split buffer %llu. nritems (unsigned long)btrfs_header_chunk_tree_uuid(split), BTRFS_UUID_SIZE); - tree_mod_log_eb_copy(root->fs_info, split, c, 0, mid, c_nritems - mid); + tree_mod_log_eb_copy(root->fs_info, split, c, 0, mid, c_nritems - mid, + tree_mod_log_removal); copy_extent_buffer(split, c, btrfs_node_key_ptr_offset(0), btrfs_node_key_ptr_offset(mid), -- 1.7.1 -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
