lookup.cc

/*-
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * Copyright (c) 2019 The FreeBSD Foundation
 *
 * This software was developed by BFF Storage Systems, LLC under sponsorship
 * from the FreeBSD Foundation.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

extern "C" {
#include <sys/param.h>
#include <sys/mount.h>

#include <fcntl.h>
#include <unistd.h>
}

#include "mockfs.hh"
#include "utils.hh"

using namespace testing;

class Lookup: public FuseTest {};

class Lookup_7_8: public Lookup {
public:
virtual void SetUp() {
	m_kernel_minor_version = 8;
	Lookup::SetUp();
}
};

class LookupExportable: public Lookup {
public:
virtual void SetUp() {
	m_init_flags = FUSE_EXPORT_SUPPORT;
	Lookup::SetUp();
}
};

/*
 * If lookup returns a non-zero cache timeout, then subsequent VOP_GETATTRs
 * should use the cached attributes, rather than query the daemon
 */
TEST_F(Lookup, attr_cache)
{
	const char FULLPATH[] = "mountpoint/some_file.txt";
	const char RELPATH[] = "some_file.txt";
	const uint64_t ino = 42;
	const uint64_t generation = 13;
	struct stat sb;

	EXPECT_LOOKUP(FUSE_ROOT_ID, RELPATH)
	.WillOnce(Invoke(ReturnImmediate([=](auto in __unused, auto& out) {
		SET_OUT_HEADER_LEN(out, entry);
		out.body.entry.nodeid = ino;
		out.body.entry.attr_valid = UINT64_MAX;
		out.body.entry.attr.ino = ino;	// Must match nodeid
		out.body.entry.attr.mode = S_IFREG | 0644;
		out.body.entry.attr.size = 1;
		out.body.entry.attr.blocks = 2;
		out.body.entry.attr.atime = 3;
		out.body.entry.attr.mtime = 4;
		out.body.entry.attr.ctime = 5;
		out.body.entry.attr.atimensec = 6;
		out.body.entry.attr.mtimensec = 7;
		out.body.entry.attr.ctimensec = 8;
		out.body.entry.attr.nlink = 9;
		out.body.entry.attr.uid = 10;
		out.body.entry.attr.gid = 11;
		out.body.entry.attr.rdev = 12;
		out.body.entry.generation = generation;
	})));
	/* stat(2) issues a VOP_LOOKUP followed by a VOP_GETATTR */
	ASSERT_EQ(0, stat(FULLPATH, &sb)) << strerror(errno);
	EXPECT_EQ(1, sb.st_size);
	EXPECT_EQ(2, sb.st_blocks);
	EXPECT_EQ(3, sb.st_atim.tv_sec);
	EXPECT_EQ(6, sb.st_atim.tv_nsec);
	EXPECT_EQ(4, sb.st_mtim.tv_sec);
	EXPECT_EQ(7, sb.st_mtim.tv_nsec);
	EXPECT_EQ(5, sb.st_ctim.tv_sec);
	EXPECT_EQ(8, sb.st_ctim.tv_nsec);
	EXPECT_EQ(9ull, sb.st_nlink);
	EXPECT_EQ(10ul, sb.st_uid);
	EXPECT_EQ(11ul, sb.st_gid);
	EXPECT_EQ(12ul, sb.st_rdev);
	EXPECT_EQ(ino, sb.st_ino);
	EXPECT_EQ(S_IFREG | 0644, sb.st_mode);

	// fuse(4) does not _yet_ support inode generations
	//EXPECT_EQ(generation, sb.st_gen);

	/*
	 * st_birthtim and st_flags are not supported by the fuse protocol.
	 * They're only supported as OS-specific extensions to OSX.  For
	 * birthtime, the convention for "not supported" is "negative one
	 * second".
	 */
	EXPECT_EQ(-1, sb.st_birthtim.tv_sec);
	EXPECT_EQ(0, sb.st_birthtim.tv_nsec);
	EXPECT_EQ(0u, sb.st_flags);
}

/*
 * If lookup returns a finite but non-zero cache timeout, then we should discard
 * the cached attributes and requery the daemon.
 */
TEST_F(Lookup, attr_cache_timeout)
{
	const char FULLPATH[] = "mountpoint/some_file.txt";
	const char RELPATH[] = "some_file.txt";
	const uint64_t ino = 42;
	struct stat sb;

	EXPECT_LOOKUP(FUSE_ROOT_ID, RELPATH)
	.Times(2)
	.WillRepeatedly(Invoke(ReturnImmediate([=](auto in __unused, auto& out) {
		SET_OUT_HEADER_LEN(out, entry);
		out.body.entry.nodeid = ino;
		out.body.entry.attr_valid_nsec = NAP_NS / 2;
		out.body.entry.attr.ino = ino;	// Must match nodeid
		out.body.entry.attr.mode = S_IFREG | 0644;
	})));

	/* access(2) will issue a VOP_LOOKUP and fill the attr cache */
	ASSERT_EQ(0, access(FULLPATH, F_OK)) << strerror(errno);
	/* Next access(2) will use the cached attributes */
	nap();
	/* The cache has timed out; VOP_GETATTR should query the daemon*/
	ASSERT_EQ(0, stat(FULLPATH, &sb)) << strerror(errno);
}

TEST_F(Lookup, dot)
{
	const char FULLPATH[] = "mountpoint/some_dir/.";
	const char RELDIRPATH[] = "some_dir";
	uint64_t ino = 42;

	EXPECT_LOOKUP(FUSE_ROOT_ID, RELDIRPATH)
	.WillOnce(Invoke(ReturnImmediate([=](auto in __unused, auto& out) {
		SET_OUT_HEADER_LEN(out, entry);
		out.body.entry.attr.mode = S_IFDIR | 0755;
		out.body.entry.nodeid = ino;
		out.body.entry.attr_valid = UINT64_MAX;
		out.body.entry.entry_valid = UINT64_MAX;
	})));

	/*
	 * access(2) is one of the few syscalls that will not (always) follow
	 * up a successful VOP_LOOKUP with another VOP.
	 */
	ASSERT_EQ(0, access(FULLPATH, F_OK)) << strerror(errno);
}

TEST_F(Lookup, dotdot)
{
	const char FULLPATH[] = "mountpoint/some_dir/..";
	const char RELDIRPATH[] = "some_dir";

	EXPECT_LOOKUP(FUSE_ROOT_ID, RELDIRPATH)
	.WillOnce(Invoke(ReturnImmediate([=](auto in __unused, auto& out) {
		SET_OUT_HEADER_LEN(out, entry);
		out.body.entry.attr.mode = S_IFDIR | 0755;
		out.body.entry.nodeid = 14;
		out.body.entry.attr_valid = UINT64_MAX;
		out.body.entry.entry_valid = UINT64_MAX;
	})));

	/*
	 * access(2) is one of the few syscalls that will not (always) follow
	 * up a successful VOP_LOOKUP with another VOP.
	 */
	ASSERT_EQ(0, access(FULLPATH, F_OK)) << strerror(errno);
}

/*
 * Lookup ".." when that vnode's entry cache has timed out, but its child's
 * hasn't.  Since this file system doesn't set FUSE_EXPORT_SUPPORT, we have no
 * choice but to use the cached entry, even though it expired.
 */
TEST_F(Lookup, dotdot_entry_cache_timeout)
{
	uint64_t foo_ino = 42;
	uint64_t bar_ino = 43;

	EXPECT_LOOKUP(FUSE_ROOT_ID, "foo")
	.WillOnce(Invoke(ReturnImmediate([=](auto in __unused, auto& out) {
		SET_OUT_HEADER_LEN(out, entry);
		out.body.entry.attr.mode = S_IFDIR | 0755;
		out.body.entry.nodeid = foo_ino;
		out.body.entry.attr_valid = UINT64_MAX;
		out.body.entry.entry_valid = 0;	// immediate timeout
	})));
	EXPECT_LOOKUP(foo_ino, "bar")
	.WillOnce(Invoke(ReturnImmediate([=](auto in __unused, auto& out) {
		SET_OUT_HEADER_LEN(out, entry);
		out.body.entry.attr.mode = S_IFDIR | 0755;
		out.body.entry.nodeid = bar_ino;
		out.body.entry.attr_valid = UINT64_MAX;
		out.body.entry.entry_valid = UINT64_MAX;
	})));
	expect_opendir(bar_ino);

	int fd = open("mountpoint/foo/bar", O_EXEC| O_DIRECTORY);
	ASSERT_LE(0, fd) << strerror(errno);
	EXPECT_EQ(0, faccessat(fd, "../..", F_OK, 0)) << strerror(errno);
}

/*
 * Lookup ".." for a vnode with no valid parent nid
 * Regression test for https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=259974
 * Since the file system is not exportable, we have no choice but to return an
 * error.
 */
TEST_F(Lookup, dotdot_no_parent_nid)
{
	uint64_t foo_ino = 42;
	uint64_t bar_ino = 43;
	int fd;

	EXPECT_LOOKUP(FUSE_ROOT_ID, "foo")
	.WillOnce(Invoke(ReturnImmediate([=](auto in __unused, auto& out) {
		SET_OUT_HEADER_LEN(out, entry);
		out.body.entry.attr.mode = S_IFDIR | 0755;
		out.body.entry.nodeid = foo_ino;
		out.body.entry.attr_valid = UINT64_MAX;
		out.body.entry.entry_valid = UINT64_MAX;
	})));
	EXPECT_LOOKUP(foo_ino, "bar")
	.WillOnce(Invoke(ReturnImmediate([=](auto in __unused, auto& out) {
		SET_OUT_HEADER_LEN(out, entry);
		out.body.entry.attr.mode = S_IFDIR | 0755;
		out.body.entry.nodeid = bar_ino;
		out.body.entry.attr_valid = UINT64_MAX;
		out.body.entry.entry_valid = UINT64_MAX;
	})));
	EXPECT_CALL(*m_mock, process(
		ResultOf([=](auto in) {
			return (in.header.opcode == FUSE_OPENDIR);
		}, Eq(true)),
		_)
	).WillOnce(Invoke(ReturnImmediate([=](auto in __unused, auto& out) {
		SET_OUT_HEADER_LEN(out, open);
	})));
	expect_forget(foo_ino, 1, NULL);

	fd = open("mountpoint/foo/bar", O_EXEC| O_DIRECTORY);
	ASSERT_LE(0, fd) << strerror(errno);
	// Try (and fail) to unmount the file system, to reclaim the mountpoint
	// and foo vnodes.
	ASSERT_NE(0, unmount("mountpoint", 0));
	EXPECT_EQ(EBUSY, errno);
	nap();		// Because vnode reclamation is asynchronous
	EXPECT_NE(0, faccessat(fd, "../..", F_OK, 0));
	EXPECT_EQ(ESTALE, errno);
}

/*
 * A daemon that returns an illegal error value should be handled gracefully.
 * Regression test for https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=263220
 */
TEST_F(Lookup, ejustreturn)
{
	const char FULLPATH[] = "mountpoint/does_not_exist";
	const char RELPATH[] = "does_not_exist";

	EXPECT_LOOKUP(FUSE_ROOT_ID, RELPATH)
	.WillOnce(Invoke(ReturnImmediate([=](auto in __unused, auto& out) {
		out.header.len = sizeof(out.header);
		out.header.error = 2;
		out.expected_errno = EINVAL;
	})));

	EXPECT_NE(0, access(FULLPATH, F_OK));

	EXPECT_EQ(EIO, errno);
}

TEST_F(Lookup, enoent)
{
	const char FULLPATH[] = "mountpoint/does_not_exist";
	const char RELPATH[] = "does_not_exist";

	EXPECT_LOOKUP(FUSE_ROOT_ID, RELPATH)
	.WillOnce(Invoke(ReturnErrno(ENOENT)));
	EXPECT_NE(0, access(FULLPATH, F_OK));
	EXPECT_EQ(ENOENT, errno);
}

TEST_F(Lookup, enotdir)
{
	const char FULLPATH[] = "mountpoint/not_a_dir/some_file.txt";
	const char RELPATH[] = "not_a_dir";

	EXPECT_LOOKUP(FUSE_ROOT_ID, RELPATH)
	.WillOnce(Invoke(ReturnImmediate([=](auto in __unused, auto& out) {
		SET_OUT_HEADER_LEN(out, entry);
		out.body.entry.entry_valid = UINT64_MAX;
		out.body.entry.attr.mode = S_IFREG | 0644;
		out.body.entry.nodeid = 42;
	})));

	ASSERT_EQ(-1, access(FULLPATH, F_OK));
	ASSERT_EQ(ENOTDIR, errno);
}

/*
 * If lookup returns a non-zero entry timeout, then subsequent VOP_LOOKUPs
 * should use the cached inode rather than requery the daemon
 */
TEST_F(Lookup, entry_cache)
{
	const char FULLPATH[] = "mountpoint/some_file.txt";
	const char RELPATH[] = "some_file.txt";

	EXPECT_LOOKUP(FUSE_ROOT_ID, RELPATH)
	.WillOnce(Invoke(ReturnImmediate([=](auto in __unused, auto& out) {
		SET_OUT_HEADER_LEN(out, entry);
		out.body.entry.entry_valid = UINT64_MAX;
		out.body.entry.attr.mode = S_IFREG | 0644;
		out.body.entry.nodeid = 14;
	})));
	ASSERT_EQ(0, access(FULLPATH, F_OK)) << strerror(errno);
	/* The second access(2) should use the cache */
	ASSERT_EQ(0, access(FULLPATH, F_OK)) << strerror(errno);
}

/* 
 * If the daemon returns an error of 0 and an inode of 0, that's a flag for
 * "ENOENT and cache it" with the given entry_timeout
 */
TEST_F(Lookup, entry_cache_negative)
{
	struct timespec entry_valid = {.tv_sec = TIME_T_MAX, .tv_nsec = 0};

	EXPECT_LOOKUP(FUSE_ROOT_ID, "does_not_exist")
	.Times(1)
	.WillOnce(Invoke(ReturnNegativeCache(&entry_valid)));

	EXPECT_NE(0, access("mountpoint/does_not_exist", F_OK));
	EXPECT_EQ(ENOENT, errno);
	EXPECT_NE(0, access("mountpoint/does_not_exist", F_OK));
	EXPECT_EQ(ENOENT, errno);
}

/* Negative entry caches should timeout, too */
TEST_F(Lookup, entry_cache_negative_timeout)
{
	const char *RELPATH = "does_not_exist";
	const char *FULLPATH = "mountpoint/does_not_exist";
	struct timespec entry_valid = {.tv_sec = 0, .tv_nsec = NAP_NS / 2};

	EXPECT_LOOKUP(FUSE_ROOT_ID, RELPATH)
	.Times(2)
	.WillRepeatedly(Invoke(ReturnNegativeCache(&entry_valid)));

	EXPECT_NE(0, access(FULLPATH, F_OK));
	EXPECT_EQ(ENOENT, errno);

	nap();

	/* The cache has timed out; VOP_LOOKUP should requery the daemon*/
	EXPECT_NE(0, access(FULLPATH, F_OK));
	EXPECT_EQ(ENOENT, errno);
}

/*
 * If lookup returns a finite but non-zero entry cache timeout, then we should
 * discard the cached inode and requery the daemon
 */
TEST_F(Lookup, entry_cache_timeout)
{
	const char FULLPATH[] = "mountpoint/some_file.txt";
	const char RELPATH[] = "some_file.txt";

	EXPECT_LOOKUP(FUSE_ROOT_ID, RELPATH)
	.Times(2)
	.WillRepeatedly(Invoke(ReturnImmediate([=](auto in __unused, auto& out) {
		SET_OUT_HEADER_LEN(out, entry);
		out.body.entry.entry_valid_nsec = NAP_NS / 2;
		out.body.entry.attr.mode = S_IFREG | 0644;
		out.body.entry.nodeid = 14;
	})));

	/* access(2) will issue a VOP_LOOKUP and fill the entry cache */
	ASSERT_EQ(0, access(FULLPATH, F_OK)) << strerror(errno);
	/* Next access(2) will use the cached entry */
	ASSERT_EQ(0, access(FULLPATH, F_OK)) << strerror(errno);
	nap();
	/* The cache has timed out; VOP_LOOKUP should requery the daemon*/
	ASSERT_EQ(0, access(FULLPATH, F_OK)) << strerror(errno);
}

TEST_F(Lookup, ok)
{
	const char FULLPATH[] = "mountpoint/some_file.txt";
	const char RELPATH[] = "some_file.txt";

	EXPECT_LOOKUP(FUSE_ROOT_ID, RELPATH)
	.WillOnce(Invoke(ReturnImmediate([=](auto in __unused, auto& out) {
		SET_OUT_HEADER_LEN(out, entry);
		out.body.entry.attr.mode = S_IFREG | 0644;
		out.body.entry.nodeid = 14;
	})));
	/*
	 * access(2) is one of the few syscalls that will not (always) follow
	 * up a successful VOP_LOOKUP with another VOP.
	 */
	ASSERT_EQ(0, access(FULLPATH, F_OK)) << strerror(errno);
}

/*
 * Lookup in a subdirectory of the fuse mount.  The naughty server returns the
 * same inode for the child as for the parent.
 */
TEST_F(Lookup, parent_inode)
{
	const char FULLPATH[] = "mountpoint/some_dir/some_file.txt";
	const char DIRPATH[] = "some_dir";
	const char RELPATH[] = "some_file.txt";
	uint64_t dir_ino = 2;

	EXPECT_LOOKUP(FUSE_ROOT_ID, DIRPATH)
	.WillOnce(Invoke(ReturnImmediate([=](auto in __unused, auto& out) {
		SET_OUT_HEADER_LEN(out, entry);
		out.body.entry.attr.mode = S_IFDIR | 0755;
		out.body.entry.nodeid = dir_ino;
	})));
	EXPECT_LOOKUP(dir_ino, RELPATH)
	.WillOnce(Invoke(ReturnImmediate([=](auto in __unused, auto& out) {
		SET_OUT_HEADER_LEN(out, entry);
		out.body.entry.attr.mode = S_IFREG | 0644;
		out.body.entry.nodeid = dir_ino;
	})));
	/*
	 * access(2) is one of the few syscalls that will not (always) follow
	 * up a successful VOP_LOOKUP with another VOP.
	 */
	ASSERT_EQ(-1, access(FULLPATH, F_OK));
	ASSERT_EQ(EIO, errno);
}

// Lookup in a subdirectory of the fuse mount
TEST_F(Lookup, subdir)
{
	const char FULLPATH[] = "mountpoint/some_dir/some_file.txt";
	const char DIRPATH[] = "some_dir";
	const char RELPATH[] = "some_file.txt";
	uint64_t dir_ino = 2;
	uint64_t file_ino = 3;

	EXPECT_LOOKUP(FUSE_ROOT_ID, DIRPATH)
	.WillOnce(Invoke(ReturnImmediate([=](auto in __unused, auto& out) {
		SET_OUT_HEADER_LEN(out, entry);
		out.body.entry.attr.mode = S_IFDIR | 0755;
		out.body.entry.nodeid = dir_ino;
	})));
	EXPECT_LOOKUP(dir_ino, RELPATH)
	.WillOnce(Invoke(ReturnImmediate([=](auto in __unused, auto& out) {
		SET_OUT_HEADER_LEN(out, entry);
		out.body.entry.attr.mode = S_IFREG | 0644;
		out.body.entry.nodeid = file_ino;
	})));
	/*
	 * access(2) is one of the few syscalls that will not (always) follow
	 * up a successful VOP_LOOKUP with another VOP.
	 */
	ASSERT_EQ(0, access(FULLPATH, F_OK)) << strerror(errno);
}

/*
 * The server returns two different vtypes for the same nodeid.  This is
 * technically allowed if the entry's cache has already expired.
 * https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=258022
 */
TEST_F(Lookup, vtype_conflict)
{
	const char FIRSTFULLPATH[] = "mountpoint/foo";
	const char SECONDFULLPATH[] = "mountpoint/bar";
	const char FIRSTRELPATH[] = "foo";
	const char SECONDRELPATH[] = "bar";
	uint64_t ino = 42;

	EXPECT_LOOKUP(FUSE_ROOT_ID, FIRSTRELPATH)
	.WillOnce(Invoke(
		ReturnImmediate([=](auto in __unused, auto& out) {
		SET_OUT_HEADER_LEN(out, entry);
		out.body.entry.attr.mode = S_IFDIR | 0644;
		out.body.entry.nodeid = ino;
		out.body.entry.attr.nlink = 1;
	})));
	expect_lookup(SECONDRELPATH, ino, S_IFREG | 0755, 0, 1, UINT64_MAX);
	// VOP_FORGET happens asynchronously, so it may or may not arrive
	// before the test completes.
	EXPECT_CALL(*m_mock, process(
		ResultOf([=](auto in) {
			return (in.header.opcode == FUSE_FORGET &&
				in.header.nodeid == ino &&
				in.body.forget.nlookup == 1);
		}, Eq(true)),
		_)
	).Times(AtMost(1))
	.WillOnce(Invoke([=](auto in __unused, auto &out __unused) { }));

	ASSERT_EQ(0, access(FIRSTFULLPATH, F_OK)) << strerror(errno);
	EXPECT_EQ(0, access(SECONDFULLPATH, F_OK)) << strerror(errno);
}

TEST_F(Lookup_7_8, ok)
{
	const char FULLPATH[] = "mountpoint/some_file.txt";
	const char RELPATH[] = "some_file.txt";

	EXPECT_LOOKUP(FUSE_ROOT_ID, RELPATH)
	.WillOnce(Invoke(ReturnImmediate([=](auto in __unused, auto& out) {
		SET_OUT_HEADER_LEN(out, entry_7_8);
		out.body.entry.attr.mode = S_IFREG | 0644;
		out.body.entry.nodeid = 14;
	})));
	/*
	 * access(2) is one of the few syscalls that will not (always) follow
	 * up a successful VOP_LOOKUP with another VOP.
	 */
	ASSERT_EQ(0, access(FULLPATH, F_OK)) << strerror(errno);
}

/*
 * Lookup ".." when that vnode's entry cache has timed out, but its child's
 * hasn't.
 */
TEST_F(LookupExportable, dotdot_entry_cache_timeout)
{
	uint64_t foo_ino = 42;
	uint64_t bar_ino = 43;

	EXPECT_LOOKUP(FUSE_ROOT_ID, "foo")
	.WillOnce(Invoke(ReturnImmediate([=](auto in __unused, auto& out) {
		SET_OUT_HEADER_LEN(out, entry);
		out.body.entry.attr.mode = S_IFDIR | 0755;
		out.body.entry.nodeid = foo_ino;
		out.body.entry.attr.ino = foo_ino;
		out.body.entry.attr_valid = UINT64_MAX;
		out.body.entry.entry_valid = 0;	// immediate timeout
	})));
	EXPECT_LOOKUP(foo_ino, "bar")
	.WillOnce(Invoke(ReturnImmediate([=](auto in __unused, auto& out) {
		SET_OUT_HEADER_LEN(out, entry);
		out.body.entry.attr.mode = S_IFDIR | 0755;
		out.body.entry.nodeid = bar_ino;
		out.body.entry.attr.ino = bar_ino;
		out.body.entry.attr_valid = UINT64_MAX;
		out.body.entry.entry_valid = UINT64_MAX;
	})));
	expect_opendir(bar_ino);
	EXPECT_LOOKUP(foo_ino, "..")
	.WillOnce(Invoke(ReturnImmediate([=](auto in __unused, auto& out) {
		SET_OUT_HEADER_LEN(out, entry);
		out.body.entry.attr.mode = S_IFDIR | 0755;
		out.body.entry.nodeid = FUSE_ROOT_ID;
		out.body.entry.attr.ino = FUSE_ROOT_ID;
		out.body.entry.attr_valid = UINT64_MAX;
		out.body.entry.entry_valid = UINT64_MAX;
	})));

	int fd = open("mountpoint/foo/bar", O_EXEC| O_DIRECTORY);
	ASSERT_LE(0, fd) << strerror(errno);
	/* FreeBSD's fusefs driver always uses the same cache expiration time
	 * for ".." as for the directory itself.  So we need to look up two
	 * levels to find an expired ".." cache entry.
	 */
	EXPECT_EQ(0, faccessat(fd, "../..", F_OK, 0)) << strerror(errno);
}

/*
 * Lookup ".." for a vnode with no valid parent nid
 * Regression test for https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=259974
 * Since the file system is exportable, we should resolve the problem by
 * sending a FUSE_LOOKUP for "..".
 */
TEST_F(LookupExportable, dotdot_no_parent_nid)
{
	uint64_t foo_ino = 42;
	uint64_t bar_ino = 43;
	int fd;

	EXPECT_LOOKUP(FUSE_ROOT_ID, "foo")
	.WillOnce(Invoke(ReturnImmediate([=](auto in __unused, auto& out) {
		SET_OUT_HEADER_LEN(out, entry);
		out.body.entry.attr.mode = S_IFDIR | 0755;
		out.body.entry.nodeid = foo_ino;
		out.body.entry.attr.ino = foo_ino;
		out.body.entry.attr_valid = UINT64_MAX;
		out.body.entry.entry_valid = UINT64_MAX;
	})));
	EXPECT_LOOKUP(foo_ino, "bar")
	.WillOnce(Invoke(ReturnImmediate([=](auto in __unused, auto& out) {
		SET_OUT_HEADER_LEN(out, entry);
		out.body.entry.attr.mode = S_IFDIR | 0755;
		out.body.entry.nodeid = bar_ino;
		out.body.entry.attr.ino = bar_ino;
		out.body.entry.attr_valid = UINT64_MAX;
		out.body.entry.entry_valid = UINT64_MAX;
	})));
	EXPECT_CALL(*m_mock, process(
		ResultOf([=](auto in) {
			return (in.header.opcode == FUSE_OPENDIR);
		}, Eq(true)),
		_)
	).WillOnce(Invoke(ReturnImmediate([=](auto in __unused, auto& out) {
		SET_OUT_HEADER_LEN(out, open);
	})));
	expect_forget(foo_ino, 1, NULL);
	EXPECT_LOOKUP(bar_ino, "..")
	.WillOnce(Invoke(ReturnImmediate([=](auto in __unused, auto& out) {
		SET_OUT_HEADER_LEN(out, entry);
		out.body.entry.attr.mode = S_IFDIR | 0755;
		out.body.entry.nodeid = foo_ino;
		out.body.entry.attr.ino = foo_ino;
		out.body.entry.attr_valid = UINT64_MAX;
		out.body.entry.entry_valid = UINT64_MAX;
	})));
	EXPECT_LOOKUP(foo_ino, "..")
	.WillOnce(Invoke(ReturnImmediate([=](auto in __unused, auto& out) {
		SET_OUT_HEADER_LEN(out, entry);
		out.body.entry.attr.mode = S_IFDIR | 0755;
		out.body.entry.nodeid = FUSE_ROOT_ID;
		out.body.entry.attr.ino = FUSE_ROOT_ID;
		out.body.entry.attr_valid = UINT64_MAX;
		out.body.entry.entry_valid = UINT64_MAX;
	})));

	fd = open("mountpoint/foo/bar", O_EXEC| O_DIRECTORY);
	ASSERT_LE(0, fd) << strerror(errno);
	// Try (and fail) to unmount the file system, to reclaim the mountpoint
	// and foo vnodes.
	ASSERT_NE(0, unmount("mountpoint", 0));
	EXPECT_EQ(EBUSY, errno);
	nap();		// Because vnode reclamation is asynchronous
	EXPECT_EQ(0, faccessat(fd, "../..", F_OK, 0)) << strerror(errno);
}