Btrfs: fix return value for __tree_mod_log_oldest_root (a95236d9) · Commits · 戴 / test

fs/btrfs/ctree.c

+20 −13

Original line number	Diff line number	Diff line
		@@ -1023,6 +1023,10 @@ __tree_mod_log_oldest_root(struct btrfs_fs_info *fs_info,
		looped = 1;
		}

		/* if there's no old root to return, return what we found instead */
		if (!found)
		found = tm;

		return found;
		}

		@@ -1155,18 +1159,24 @@ get_old_root(struct btrfs_root *root, u64 time_seq)
		{
		struct tree_mod_elem *tm;
		struct extent_buffer *eb;
		struct tree_mod_root *old_root;
		struct tree_mod_root *old_root = NULL;
		u64 old_generation;
		u64 logical;

		eb = btrfs_read_lock_root_node(root);
		tm = __tree_mod_log_oldest_root(root->fs_info, root, time_seq);
		if (!tm)
		return root->node;

		if (tm->op == MOD_LOG_ROOT_REPLACE) {
		old_root = &tm->old_root;
		old_generation = tm->generation;
		logical = old_root->logical;
		} else {
		logical = root->node->start;
		}

		tm = tree_mod_log_search(root->fs_info, old_root->logical, time_seq);
		tm = tree_mod_log_search(root->fs_info, logical, time_seq);
		/*
		* there was an item in the log when __tree_mod_log_oldest_root
		* returned. this one must not go away, because the time_seq passed to
		@@ -1174,26 +1184,23 @@ get_old_root(struct btrfs_root *root, u64 time_seq)
		*/
		BUG_ON(!tm);

		if (old_root->logical == root->node->start) {
		/* there are logged operations for the current root */
		eb = btrfs_clone_extent_buffer(root->node);
		} else {
		/* there's a root replace operation for the current root */
		if (old_root)
		eb = alloc_dummy_extent_buffer(tm->index << PAGE_CACHE_SHIFT,
		root->nodesize);
		}
		else
		eb = btrfs_clone_extent_buffer(root->node);
		btrfs_tree_read_unlock(root->node);
		free_extent_buffer(root->node);
		if (!eb)
		return NULL;
		btrfs_tree_read_lock(eb);
		if (old_root->logical != root->node->start) {
		if (old_root) {
		btrfs_set_header_bytenr(eb, eb->start);
		btrfs_set_header_backref_rev(eb, BTRFS_MIXED_BACKREF_REV);
		btrfs_set_header_owner(eb, root->root_key.objectid);
		}
		btrfs_set_header_level(eb, old_root->level);
		btrfs_set_header_generation(eb, old_generation);
		}
		__tree_mod_log_rewind(eb, time_seq, tm);
		extent_buffer_get(eb);

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