/*-
 * 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);
}