xref: /freebsd/tests/sys/fs/fusefs/write.cc (revision 473957941922d17be72089e385e2e2a995fd0e1c)

/*-
 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
 *
 * 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.
 *
 * $FreeBSD$
 */

extern "C" {
#include <sys/param.h>
#include <sys/mman.h>
#include <sys/resource.h>
#include <sys/stat.h>
#include <sys/time.h>
#include <sys/uio.h>

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

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

using namespace testing;

class Write: public FuseTest {

public:
static sig_atomic_t s_sigxfsz;

void SetUp() {
	s_sigxfsz = 0;
	FuseTest::SetUp();
}

void TearDown() {
	struct sigaction sa;

	bzero(&sa, sizeof(sa));
	sa.sa_handler = SIG_DFL;
	sigaction(SIGXFSZ, &sa, NULL);

	FuseTest::TearDown();
}

void expect_lookup(const char *relpath, uint64_t ino, uint64_t size)
{
	FuseTest::expect_lookup(relpath, ino, S_IFREG | 0644, size, 1);
}

void expect_release(uint64_t ino, ProcessMockerT r)
{
	EXPECT_CALL(*m_mock, process(
		ResultOf([=](auto in) {
			return (in.header.opcode == FUSE_RELEASE &&
				in.header.nodeid == ino);
		}, Eq(true)),
		_)
	).WillRepeatedly(Invoke(r));
}

void expect_write(uint64_t ino, uint64_t offset, uint64_t isize,
	uint64_t osize, const void *contents)
{
	FuseTest::expect_write(ino, offset, isize, osize, 0, 0, contents);
}

/* Expect a write that may or may not come, depending on the cache mode */
void maybe_expect_write(uint64_t ino, uint64_t offset, uint64_t size,
	const void *contents)
{
	EXPECT_CALL(*m_mock, process(
		ResultOf([=](auto in) {
			const char *buf = (const char*)in.body.bytes +
				sizeof(struct fuse_write_in);

			return (in.header.opcode == FUSE_WRITE &&
				in.header.nodeid == ino &&
				in.body.write.offset == offset  &&
				in.body.write.size == size &&
				0 == bcmp(buf, contents, size));
		}, Eq(true)),
		_)
	).Times(AtMost(1))
	.WillRepeatedly(Invoke(
		ReturnImmediate([=](auto in __unused, auto& out) {
			SET_OUT_HEADER_LEN(out, write);
			out.body.write.size = size;
		})
	));
}

};

sig_atomic_t Write::s_sigxfsz = 0;

class Write_7_8: public FuseTest {

public:
virtual void SetUp() {
	m_kernel_minor_version = 8;
	FuseTest::SetUp();
}

void expect_lookup(const char *relpath, uint64_t ino, uint64_t size)
{
	FuseTest::expect_lookup_7_8(relpath, ino, S_IFREG | 0644, size, 1);
}

};

class AioWrite: public Write {
virtual void SetUp() {
	if (!is_unsafe_aio_enabled())
		GTEST_SKIP() <<
			"vfs.aio.enable_unsafe must be set for this test";
	FuseTest::SetUp();
}
};

/* Tests for the writeback cache mode */
class WriteBack: public Write {
public:
virtual void SetUp() {
	m_init_flags |= FUSE_WRITEBACK_CACHE;
	FuseTest::SetUp();
	if (IsSkipped())
		return;
}

void expect_write(uint64_t ino, uint64_t offset, uint64_t isize,
	uint64_t osize, const void *contents)
{
	FuseTest::expect_write(ino, offset, isize, osize, FUSE_WRITE_CACHE, 0,
		contents);
}
};

class WriteBackAsync: public WriteBack {
public:
virtual void SetUp() {
	m_async = true;
	WriteBack::SetUp();
}
};

class TimeGran: public WriteBackAsync, public WithParamInterface<unsigned> {
public:
virtual void SetUp() {
	m_time_gran = 1 << GetParam();
	WriteBackAsync::SetUp();
}
};

/* Tests for clustered writes with WriteBack cacheing */
class WriteCluster: public WriteBack {
public:
virtual void SetUp() {
	m_async = true;
	m_maxwrite = 1 << 25;	// Anything larger than MAXPHYS will suffice
	WriteBack::SetUp();
	if (m_maxphys < 2 * DFLTPHYS)
		GTEST_SKIP() << "MAXPHYS must be at least twice DFLTPHYS"
			<< " for this test";
	if (m_maxphys < 2 * m_maxbcachebuf)
		GTEST_SKIP() << "MAXPHYS must be at least twice maxbcachebuf"
			<< " for this test";
}
};

void sigxfsz_handler(int __unused sig) {
	Write::s_sigxfsz = 1;
}

/* AIO writes need to set the header's pid field correctly */
/* https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=236379 */
TEST_F(AioWrite, DISABLED_aio_write)
{
	const char FULLPATH[] = "mountpoint/some_file.txt";
	const char RELPATH[] = "some_file.txt";
	const char *CONTENTS = "abcdefgh";
	uint64_t ino = 42;
	uint64_t offset = 4096;
	int fd;
	ssize_t bufsize = strlen(CONTENTS);
	struct aiocb iocb, *piocb;

	expect_lookup(RELPATH, ino, 0);
	expect_open(ino, 0, 1);
	expect_write(ino, offset, bufsize, bufsize, CONTENTS);

	fd = open(FULLPATH, O_WRONLY);
	EXPECT_LE(0, fd) << strerror(errno);

	iocb.aio_nbytes = bufsize;
	iocb.aio_fildes = fd;
	iocb.aio_buf = __DECONST(void *, CONTENTS);
	iocb.aio_offset = offset;
	iocb.aio_sigevent.sigev_notify = SIGEV_NONE;
	ASSERT_EQ(0, aio_write(&iocb)) << strerror(errno);
	ASSERT_EQ(bufsize, aio_waitcomplete(&piocb, NULL)) << strerror(errno);
	leak(fd);
}

/*
 * When a file is opened with O_APPEND, we should forward that flag to
 * FUSE_OPEN (tested by Open.o_append) but still attempt to calculate the
 * offset internally.  That way we'll work both with filesystems that
 * understand O_APPEND (and ignore the offset) and filesystems that don't (and
 * simply use the offset).
 *
 * Note that verifying the O_APPEND flag in FUSE_OPEN is done in the
 * Open.o_append test.
 */
TEST_F(Write, append)
{
	const ssize_t BUFSIZE = 9;
	const char FULLPATH[] = "mountpoint/some_file.txt";
	const char RELPATH[] = "some_file.txt";
	const char CONTENTS[BUFSIZE] = "abcdefgh";
	uint64_t ino = 42;
	/*
	 * Set offset to a maxbcachebuf boundary so we don't need to RMW when
	 * using writeback caching
	 */
	uint64_t initial_offset = m_maxbcachebuf;
	int fd;

	expect_lookup(RELPATH, ino, initial_offset);
	expect_open(ino, 0, 1);
	expect_write(ino, initial_offset, BUFSIZE, BUFSIZE, CONTENTS);

	/* Must open O_RDWR or fuse(4) implicitly sets direct_io */
	fd = open(FULLPATH, O_RDWR | O_APPEND);
	EXPECT_LE(0, fd) << strerror(errno);

	ASSERT_EQ(BUFSIZE, write(fd, CONTENTS, BUFSIZE)) << strerror(errno);
	leak(fd);
}

/* If a file is cached, then appending to the end should not cause a read */
TEST_F(Write, append_to_cached)
{
	const ssize_t BUFSIZE = 9;
	const char FULLPATH[] = "mountpoint/some_file.txt";
	const char RELPATH[] = "some_file.txt";
	char *oldcontents, *oldbuf;
	const char CONTENTS[BUFSIZE] = "abcdefgh";
	uint64_t ino = 42;
	/*
	 * Set offset in between maxbcachebuf boundary to test buffer handling
	 */
	uint64_t oldsize = m_maxbcachebuf / 2;
	int fd;

	oldcontents = (char*)calloc(1, oldsize);
	ASSERT_NE(nullptr, oldcontents) << strerror(errno);
	oldbuf = (char*)malloc(oldsize);
	ASSERT_NE(nullptr, oldbuf) << strerror(errno);

	expect_lookup(RELPATH, ino, oldsize);
	expect_open(ino, 0, 1);
	expect_read(ino, 0, oldsize, oldsize, oldcontents);
	maybe_expect_write(ino, oldsize, BUFSIZE, CONTENTS);

	/* Must open O_RDWR or fuse(4) implicitly sets direct_io */
	fd = open(FULLPATH, O_RDWR | O_APPEND);
	EXPECT_LE(0, fd) << strerror(errno);

	/* Read the old data into the cache */
	ASSERT_EQ((ssize_t)oldsize, read(fd, oldbuf, oldsize))
		<< strerror(errno);

	/* Write the new data.  There should be no more read operations */
	ASSERT_EQ(BUFSIZE, write(fd, CONTENTS, BUFSIZE)) << strerror(errno);
	leak(fd);
	free(oldbuf);
	free(oldcontents);
}

TEST_F(Write, append_direct_io)
{
	const ssize_t BUFSIZE = 9;
	const char FULLPATH[] = "mountpoint/some_file.txt";
	const char RELPATH[] = "some_file.txt";
	const char CONTENTS[BUFSIZE] = "abcdefgh";
	uint64_t ino = 42;
	uint64_t initial_offset = 4096;
	int fd;

	expect_lookup(RELPATH, ino, initial_offset);
	expect_open(ino, FOPEN_DIRECT_IO, 1);
	expect_write(ino, initial_offset, BUFSIZE, BUFSIZE, CONTENTS);

	fd = open(FULLPATH, O_WRONLY | O_APPEND);
	EXPECT_LE(0, fd) << strerror(errno);

	ASSERT_EQ(BUFSIZE, write(fd, CONTENTS, BUFSIZE)) << strerror(errno);
	leak(fd);
}

/* A direct write should evict any overlapping cached data */
TEST_F(Write, direct_io_evicts_cache)
{
	const char FULLPATH[] = "mountpoint/some_file.txt";
	const char RELPATH[] = "some_file.txt";
	const char CONTENTS0[] = "abcdefgh";
	const char CONTENTS1[] = "ijklmnop";
	uint64_t ino = 42;
	int fd;
	ssize_t bufsize = strlen(CONTENTS0) + 1;
	char readbuf[bufsize];

	expect_lookup(RELPATH, ino, bufsize);
	expect_open(ino, 0, 1);
	expect_read(ino, 0, bufsize, bufsize, CONTENTS0);
	expect_write(ino, 0, bufsize, bufsize, CONTENTS1);

	fd = open(FULLPATH, O_RDWR);
	EXPECT_LE(0, fd) << strerror(errno);

	// Prime cache
	ASSERT_EQ(bufsize, read(fd, readbuf, bufsize)) << strerror(errno);

	// Write directly, evicting cache
	ASSERT_EQ(0, fcntl(fd, F_SETFL, O_DIRECT)) << strerror(errno);
	ASSERT_EQ(0, lseek(fd, 0, SEEK_SET)) << strerror(errno);
	ASSERT_EQ(bufsize, write(fd, CONTENTS1, bufsize)) << strerror(errno);

	// Read again.  Cache should be bypassed
	expect_read(ino, 0, bufsize, bufsize, CONTENTS1);
	ASSERT_EQ(0, fcntl(fd, F_SETFL, 0)) << strerror(errno);
	ASSERT_EQ(0, lseek(fd, 0, SEEK_SET)) << strerror(errno);
	ASSERT_EQ(bufsize, read(fd, readbuf, bufsize)) << strerror(errno);
	ASSERT_STREQ(readbuf, CONTENTS1);

	leak(fd);
}

/*
 * If the server doesn't return FOPEN_DIRECT_IO during FUSE_OPEN, then it's not
 * allowed to return a short write for that file handle.  However, if it does
 * then we should still do our darndest to handle it by resending the unwritten
 * portion.
 */
TEST_F(Write, indirect_io_short_write)
{
	const char FULLPATH[] = "mountpoint/some_file.txt";
	const char RELPATH[] = "some_file.txt";
	const char *CONTENTS = "abcdefghijklmnop";
	uint64_t ino = 42;
	int fd;
	ssize_t bufsize = strlen(CONTENTS);
	ssize_t bufsize0 = 11;
	ssize_t bufsize1 = strlen(CONTENTS) - bufsize0;
	const char *contents1 = CONTENTS + bufsize0;

	expect_lookup(RELPATH, ino, 0);
	expect_open(ino, 0, 1);
	expect_write(ino, 0, bufsize, bufsize0, CONTENTS);
	expect_write(ino, bufsize0, bufsize1, bufsize1, contents1);

	fd = open(FULLPATH, O_WRONLY);
	EXPECT_LE(0, fd) << strerror(errno);

	ASSERT_EQ(bufsize, write(fd, CONTENTS, bufsize)) << strerror(errno);
	leak(fd);
}

/*
 * When the direct_io option is used, filesystems are allowed to write less
 * data than requested.  We should return the short write to userland.
 */
TEST_F(Write, direct_io_short_write)
{
	const char FULLPATH[] = "mountpoint/some_file.txt";
	const char RELPATH[] = "some_file.txt";
	const char *CONTENTS = "abcdefghijklmnop";
	uint64_t ino = 42;
	int fd;
	ssize_t bufsize = strlen(CONTENTS);
	ssize_t halfbufsize = bufsize / 2;

	expect_lookup(RELPATH, ino, 0);
	expect_open(ino, FOPEN_DIRECT_IO, 1);
	expect_write(ino, 0, bufsize, halfbufsize, CONTENTS);

	fd = open(FULLPATH, O_WRONLY);
	EXPECT_LE(0, fd) << strerror(errno);

	ASSERT_EQ(halfbufsize, write(fd, CONTENTS, bufsize)) << strerror(errno);
	leak(fd);
}

/*
 * An insidious edge case: the filesystem returns a short write, and the
 * difference between what we requested and what it actually wrote crosses an
 * iov element boundary
 */
TEST_F(Write, direct_io_short_write_iov)
{
	const char FULLPATH[] = "mountpoint/some_file.txt";
	const char RELPATH[] = "some_file.txt";
	const char *CONTENTS0 = "abcdefgh";
	const char *CONTENTS1 = "ijklmnop";
	const char *EXPECTED0 = "abcdefghijklmnop";
	uint64_t ino = 42;
	int fd;
	ssize_t size0 = strlen(CONTENTS0) - 1;
	ssize_t size1 = strlen(CONTENTS1) + 1;
	ssize_t totalsize = size0 + size1;
	struct iovec iov[2];

	expect_lookup(RELPATH, ino, 0);
	expect_open(ino, FOPEN_DIRECT_IO, 1);
	expect_write(ino, 0, totalsize, size0, EXPECTED0);

	fd = open(FULLPATH, O_WRONLY);
	EXPECT_LE(0, fd) << strerror(errno);

	iov[0].iov_base = __DECONST(void*, CONTENTS0);
	iov[0].iov_len = strlen(CONTENTS0);
	iov[1].iov_base = __DECONST(void*, CONTENTS1);
	iov[1].iov_len = strlen(CONTENTS1);
	ASSERT_EQ(size0, writev(fd, iov, 2)) << strerror(errno);
	leak(fd);
}

/* fusefs should respect RLIMIT_FSIZE */
TEST_F(Write, rlimit_fsize)
{
	const char FULLPATH[] = "mountpoint/some_file.txt";
	const char RELPATH[] = "some_file.txt";
	const char *CONTENTS = "abcdefgh";
	struct rlimit rl;
	ssize_t bufsize = strlen(CONTENTS);
	off_t offset = 1'000'000'000;
	uint64_t ino = 42;
	int fd;

	expect_lookup(RELPATH, ino, 0);
	expect_open(ino, 0, 1);

	rl.rlim_cur = offset;
	rl.rlim_max = 10 * offset;
	ASSERT_EQ(0, setrlimit(RLIMIT_FSIZE, &rl)) << strerror(errno);
	ASSERT_NE(SIG_ERR, signal(SIGXFSZ, sigxfsz_handler)) << strerror(errno);

	fd = open(FULLPATH, O_WRONLY);

	EXPECT_LE(0, fd) << strerror(errno);

	ASSERT_EQ(-1, pwrite(fd, CONTENTS, bufsize, offset));
	EXPECT_EQ(EFBIG, errno);
	EXPECT_EQ(1, s_sigxfsz);
	leak(fd);
}

/*
 * A short read indicates EOF.  Test that nothing bad happens if we get EOF
 * during the R of a RMW operation.
 */
TEST_F(Write, eof_during_rmw)
{
	const char FULLPATH[] = "mountpoint/some_file.txt";
	const char RELPATH[] = "some_file.txt";
	const char *CONTENTS = "abcdefgh";
	const char *INITIAL   = "XXXXXXXXXX";
	uint64_t ino = 42;
	uint64_t offset = 1;
	ssize_t bufsize = strlen(CONTENTS);
	off_t orig_fsize = 10;
	off_t truncated_fsize = 5;
	off_t final_fsize = bufsize;
	int fd;

	FuseTest::expect_lookup(RELPATH, ino, S_IFREG | 0644, orig_fsize, 1);
	expect_open(ino, 0, 1);
	expect_read(ino, 0, orig_fsize, truncated_fsize, INITIAL, O_RDWR);
	expect_getattr(ino, truncated_fsize);
	expect_read(ino, 0, final_fsize, final_fsize, INITIAL, O_RDWR);
	maybe_expect_write(ino, offset, bufsize, CONTENTS);

	fd = open(FULLPATH, O_RDWR);
	EXPECT_LE(0, fd) << strerror(errno);

	ASSERT_EQ(bufsize, pwrite(fd, CONTENTS, bufsize, offset))
		<< strerror(errno);
	leak(fd);
}

/*
 * If the kernel cannot be sure which uid, gid, or pid was responsible for a
 * write, then it must set the FUSE_WRITE_CACHE bit
 */
/* https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=236378 */
TEST_F(Write, mmap)
{
	const char FULLPATH[] = "mountpoint/some_file.txt";
	const char RELPATH[] = "some_file.txt";
	const char *CONTENTS = "abcdefgh";
	uint64_t ino = 42;
	int fd;
	ssize_t bufsize = strlen(CONTENTS);
	void *p;
	uint64_t offset = 10;
	size_t len;
	void *zeros, *expected;

	len = getpagesize();

	zeros = calloc(1, len);
	ASSERT_NE(nullptr, zeros);
	expected = calloc(1, len);
	ASSERT_NE(nullptr, expected);
	memmove((uint8_t*)expected + offset, CONTENTS, bufsize);

	expect_lookup(RELPATH, ino, len);
	expect_open(ino, 0, 1);
	expect_read(ino, 0, len, len, zeros);
	/*
	 * Writes from the pager may or may not be associated with the correct
	 * pid, so they must set FUSE_WRITE_CACHE.
	 */
	FuseTest::expect_write(ino, 0, len, len, FUSE_WRITE_CACHE, 0, expected);
	expect_flush(ino, 1, ReturnErrno(0));
	expect_release(ino, ReturnErrno(0));

	fd = open(FULLPATH, O_RDWR);
	EXPECT_LE(0, fd) << strerror(errno);

	p = mmap(NULL, len, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
	ASSERT_NE(MAP_FAILED, p) << strerror(errno);

	memmove((uint8_t*)p + offset, CONTENTS, bufsize);

	ASSERT_EQ(0, munmap(p, len)) << strerror(errno);
	close(fd);	// Write mmap'd data on close

	free(expected);
	free(zeros);

	leak(fd);
}

TEST_F(Write, pwrite)
{
	const char FULLPATH[] = "mountpoint/some_file.txt";
	const char RELPATH[] = "some_file.txt";
	const char *CONTENTS = "abcdefgh";
	uint64_t ino = 42;
	uint64_t offset = m_maxbcachebuf;
	int fd;
	ssize_t bufsize = strlen(CONTENTS);

	expect_lookup(RELPATH, ino, 0);
	expect_open(ino, 0, 1);
	expect_write(ino, offset, bufsize, bufsize, CONTENTS);

	fd = open(FULLPATH, O_WRONLY);
	EXPECT_LE(0, fd) << strerror(errno);

	ASSERT_EQ(bufsize, pwrite(fd, CONTENTS, bufsize, offset))
		<< strerror(errno);
	leak(fd);
}

/* Writing a file should update its cached mtime and ctime */
TEST_F(Write, timestamps)
{
	const char FULLPATH[] = "mountpoint/some_file.txt";
	const char RELPATH[] = "some_file.txt";
	const char *CONTENTS = "abcdefgh";
	ssize_t bufsize = strlen(CONTENTS);
	uint64_t ino = 42;
	struct stat sb0, sb1;
	int fd;

	expect_lookup(RELPATH, ino, 0);
	expect_open(ino, 0, 1);
	maybe_expect_write(ino, 0, bufsize, CONTENTS);

	fd = open(FULLPATH, O_RDWR);
	EXPECT_LE(0, fd) << strerror(errno);
	ASSERT_EQ(0, fstat(fd, &sb0)) << strerror(errno);
	ASSERT_EQ(bufsize, write(fd, CONTENTS, bufsize)) << strerror(errno);

	nap();

	ASSERT_EQ(0, fstat(fd, &sb1)) << strerror(errno);

	EXPECT_EQ(sb0.st_atime, sb1.st_atime);
	EXPECT_NE(sb0.st_mtime, sb1.st_mtime);
	EXPECT_NE(sb0.st_ctime, sb1.st_ctime);

	leak(fd);
}

TEST_F(Write, write)
{
	const char FULLPATH[] = "mountpoint/some_file.txt";
	const char RELPATH[] = "some_file.txt";
	const char *CONTENTS = "abcdefgh";
	uint64_t ino = 42;
	int fd;
	ssize_t bufsize = strlen(CONTENTS);

	expect_lookup(RELPATH, ino, 0);
	expect_open(ino, 0, 1);
	expect_write(ino, 0, bufsize, bufsize, CONTENTS);

	fd = open(FULLPATH, O_WRONLY);
	EXPECT_LE(0, fd) << strerror(errno);

	ASSERT_EQ(bufsize, write(fd, CONTENTS, bufsize)) << strerror(errno);
	leak(fd);
}

/* fuse(4) should not issue writes of greater size than the daemon requests */
TEST_F(Write, write_large)
{
	const char FULLPATH[] = "mountpoint/some_file.txt";
	const char RELPATH[] = "some_file.txt";
	int *contents;
	uint64_t ino = 42;
	int fd;
	ssize_t halfbufsize, bufsize;

	halfbufsize = m_mock->m_maxwrite;
	bufsize = halfbufsize * 2;
	contents = (int*)malloc(bufsize);
	ASSERT_NE(nullptr, contents);
	for (int i = 0; i < (int)bufsize / (int)sizeof(i); i++) {
		contents[i] = i;
	}

	expect_lookup(RELPATH, ino, 0);
	expect_open(ino, 0, 1);
	maybe_expect_write(ino, 0, halfbufsize, contents);
	maybe_expect_write(ino, halfbufsize, halfbufsize,
		&contents[halfbufsize / sizeof(int)]);

	fd = open(FULLPATH, O_WRONLY);
	EXPECT_LE(0, fd) << strerror(errno);

	ASSERT_EQ(bufsize, write(fd, contents, bufsize)) << strerror(errno);
	leak(fd);

	free(contents);
}

TEST_F(Write, write_nothing)
{
	const char FULLPATH[] = "mountpoint/some_file.txt";
	const char RELPATH[] = "some_file.txt";
	const char *CONTENTS = "";
	uint64_t ino = 42;
	int fd;
	ssize_t bufsize = 0;

	expect_lookup(RELPATH, ino, 0);
	expect_open(ino, 0, 1);

	fd = open(FULLPATH, O_WRONLY);
	EXPECT_LE(0, fd) << strerror(errno);

	ASSERT_EQ(bufsize, write(fd, CONTENTS, bufsize)) << strerror(errno);
	leak(fd);
}

TEST_F(Write_7_8, write)
{
	const char FULLPATH[] = "mountpoint/some_file.txt";
	const char RELPATH[] = "some_file.txt";
	const char *CONTENTS = "abcdefgh";
	uint64_t ino = 42;
	int fd;
	ssize_t bufsize = strlen(CONTENTS);

	expect_lookup(RELPATH, ino, 0);
	expect_open(ino, 0, 1);
	expect_write_7_8(ino, 0, bufsize, bufsize, CONTENTS);

	fd = open(FULLPATH, O_WRONLY);
	EXPECT_LE(0, fd) << strerror(errno);

	ASSERT_EQ(bufsize, write(fd, CONTENTS, bufsize)) << strerror(errno);
	leak(fd);
}

/* In writeback mode, dirty data should be written on close */
TEST_F(WriteBackAsync, close)
{
	const char FULLPATH[] = "mountpoint/some_file.txt";
	const char RELPATH[] = "some_file.txt";
	const char *CONTENTS = "abcdefgh";
	uint64_t ino = 42;
	int fd;
	ssize_t bufsize = strlen(CONTENTS);

	expect_lookup(RELPATH, ino, 0);
	expect_open(ino, 0, 1);
	expect_write(ino, 0, bufsize, bufsize, CONTENTS);
	EXPECT_CALL(*m_mock, process(
		ResultOf([=](auto in) {
			return (in.header.opcode == FUSE_SETATTR);
		}, Eq(true)),
		_)
	).WillRepeatedly(Invoke(ReturnImmediate([=](auto i __unused, auto& out) {
		SET_OUT_HEADER_LEN(out, attr);
		out.body.attr.attr.ino = ino;	// Must match nodeid
	})));
	expect_flush(ino, 1, ReturnErrno(0));
	expect_release(ino, ReturnErrno(0));

	fd = open(FULLPATH, O_RDWR);
	ASSERT_LE(0, fd) << strerror(errno);

	ASSERT_EQ(bufsize, write(fd, CONTENTS, bufsize)) << strerror(errno);
	close(fd);
}

/* In writeback mode, adjacent writes will be clustered together */
TEST_F(WriteCluster, clustering)
{
	const char FULLPATH[] = "mountpoint/some_file.txt";
	const char RELPATH[] = "some_file.txt";
	uint64_t ino = 42;
	int i, fd;
	void *wbuf, *wbuf2x;
	ssize_t bufsize = m_maxbcachebuf;
	off_t filesize = 5 * bufsize;

	wbuf = malloc(bufsize);
	ASSERT_NE(nullptr, wbuf) << strerror(errno);
	memset(wbuf, 'X', bufsize);
	wbuf2x = malloc(2 * bufsize);
	ASSERT_NE(nullptr, wbuf2x) << strerror(errno);
	memset(wbuf2x, 'X', 2 * bufsize);

	expect_lookup(RELPATH, ino, filesize);
	expect_open(ino, 0, 1);
	/*
	 * Writes of bufsize-bytes each should be clustered into greater sizes.
	 * The amount of clustering is adaptive, so the first write actually
	 * issued will be 2x bufsize and subsequent writes may be larger
	 */
	expect_write(ino, 0, 2 * bufsize, 2 * bufsize, wbuf2x);
	expect_write(ino, 2 * bufsize, 2 * bufsize, 2 * bufsize, wbuf2x);
	expect_flush(ino, 1, ReturnErrno(0));
	expect_release(ino, ReturnErrno(0));

	fd = open(FULLPATH, O_RDWR);
	ASSERT_LE(0, fd) << strerror(errno);

	for (i = 0; i < 4; i++) {
		ASSERT_EQ(bufsize, write(fd, wbuf, bufsize))
			<< strerror(errno);
	}
	close(fd);
	free(wbuf2x);
	free(wbuf);
}

/*
 * When clustering writes, an I/O error to any of the cluster's children should
 * not panic the system on unmount
 */
/*
 * Disabled because it panics.
 * https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=238565
 */
TEST_F(WriteCluster, DISABLED_cluster_write_err)
{
	const char FULLPATH[] = "mountpoint/some_file.txt";
	const char RELPATH[] = "some_file.txt";
	uint64_t ino = 42;
	int i, fd;
	void *wbuf;
	ssize_t bufsize = m_maxbcachebuf;
	off_t filesize = 4 * bufsize;

	wbuf = malloc(bufsize);
	ASSERT_NE(nullptr, wbuf) << strerror(errno);
	memset(wbuf, 'X', bufsize);

	expect_lookup(RELPATH, ino, filesize);
	expect_open(ino, 0, 1);
	EXPECT_CALL(*m_mock, process(
		ResultOf([=](auto in) {
			return (in.header.opcode == FUSE_WRITE);
		}, Eq(true)),
		_)
	).WillRepeatedly(Invoke(ReturnErrno(EIO)));
	expect_flush(ino, 1, ReturnErrno(0));
	expect_release(ino, ReturnErrno(0));

	fd = open(FULLPATH, O_RDWR);
	ASSERT_LE(0, fd) << strerror(errno);

	for (i = 0; i < 3; i++) {
		ASSERT_EQ(bufsize, write(fd, wbuf, bufsize))
			<< strerror(errno);
	}
	close(fd);
	free(wbuf);
}

/*
 * In writeback mode, writes to an O_WRONLY file could trigger reads from the
 * server.  The FUSE protocol explicitly allows that.
 */
TEST_F(WriteBack, rmw)
{
	const char FULLPATH[] = "mountpoint/some_file.txt";
	const char RELPATH[] = "some_file.txt";
	const char *CONTENTS = "abcdefgh";
	const char *INITIAL   = "XXXXXXXXXX";
	uint64_t ino = 42;
	uint64_t offset = 1;
	off_t fsize = 10;
	int fd;
	ssize_t bufsize = strlen(CONTENTS);

	FuseTest::expect_lookup(RELPATH, ino, S_IFREG | 0644, fsize, 1);
	expect_open(ino, 0, 1);
	expect_read(ino, 0, fsize, fsize, INITIAL, O_WRONLY);
	maybe_expect_write(ino, offset, bufsize, CONTENTS);

	fd = open(FULLPATH, O_WRONLY);
	EXPECT_LE(0, fd) << strerror(errno);

	ASSERT_EQ(bufsize, pwrite(fd, CONTENTS, bufsize, offset))
		<< strerror(errno);
	leak(fd);
}

/*
 * Without direct_io, writes should be committed to cache
 */
TEST_F(WriteBack, cache)
{
	const char FULLPATH[] = "mountpoint/some_file.txt";
	const char RELPATH[] = "some_file.txt";
	const char *CONTENTS = "abcdefgh";
	uint64_t ino = 42;
	int fd;
	ssize_t bufsize = strlen(CONTENTS);
	uint8_t readbuf[bufsize];

	expect_lookup(RELPATH, ino, 0);
	expect_open(ino, 0, 1);
	expect_write(ino, 0, bufsize, bufsize, CONTENTS);

	fd = open(FULLPATH, O_RDWR);
	EXPECT_LE(0, fd) << strerror(errno);

	ASSERT_EQ(bufsize, write(fd, CONTENTS, bufsize)) << strerror(errno);
	/*
	 * A subsequent read should be serviced by cache, without querying the
	 * filesystem daemon
	 */
	ASSERT_EQ(0, lseek(fd, 0, SEEK_SET)) << strerror(errno);
	ASSERT_EQ(bufsize, read(fd, readbuf, bufsize)) << strerror(errno);
	leak(fd);
}

/*
 * With O_DIRECT, writes should be not committed to cache.  Admittedly this is
 * an odd test, because it would be unusual to use O_DIRECT for writes but not
 * reads.
 */
TEST_F(WriteBack, o_direct)
{
	const char FULLPATH[] = "mountpoint/some_file.txt";
	const char RELPATH[] = "some_file.txt";
	const char *CONTENTS = "abcdefgh";
	uint64_t ino = 42;
	int fd;
	ssize_t bufsize = strlen(CONTENTS);
	uint8_t readbuf[bufsize];

	expect_lookup(RELPATH, ino, 0);
	expect_open(ino, 0, 1);
	FuseTest::expect_write(ino, 0, bufsize, bufsize, 0, FUSE_WRITE_CACHE,
		CONTENTS);
	expect_read(ino, 0, bufsize, bufsize, CONTENTS);

	fd = open(FULLPATH, O_RDWR | O_DIRECT);
	EXPECT_LE(0, fd) << strerror(errno);

	ASSERT_EQ(bufsize, write(fd, CONTENTS, bufsize)) << strerror(errno);
	/* A subsequent read must query the daemon because cache is empty */
	ASSERT_EQ(0, lseek(fd, 0, SEEK_SET)) << strerror(errno);
	ASSERT_EQ(0, fcntl(fd, F_SETFL, 0)) << strerror(errno);
	ASSERT_EQ(bufsize, read(fd, readbuf, bufsize)) << strerror(errno);
	leak(fd);
}

/*
 * When mounted with -o async, the writeback cache mode should delay writes
 */
TEST_F(WriteBackAsync, delay)
{
	const char FULLPATH[] = "mountpoint/some_file.txt";
	const char RELPATH[] = "some_file.txt";
	const char *CONTENTS = "abcdefgh";
	uint64_t ino = 42;
	int fd;
	ssize_t bufsize = strlen(CONTENTS);

	expect_lookup(RELPATH, ino, 0);
	expect_open(ino, 0, 1);
	/* Write should be cached, but FUSE_WRITE shouldn't be sent */
	EXPECT_CALL(*m_mock, process(
		ResultOf([=](auto in) {
			return (in.header.opcode == FUSE_WRITE);
		}, Eq(true)),
		_)
	).Times(0);

	fd = open(FULLPATH, O_RDWR);
	EXPECT_LE(0, fd) << strerror(errno);

	ASSERT_EQ(bufsize, write(fd, CONTENTS, bufsize)) << strerror(errno);

	/* Don't close the file because that would flush the cache */
	leak(fd);
}

/*
 * A direct write should not evict dirty cached data from outside of its own
 * byte range.
 */
TEST_F(WriteBackAsync, direct_io_ignores_unrelated_cached)
{
	const char FULLPATH[] = "mountpoint/some_file.txt";
	const char RELPATH[] = "some_file.txt";
	const char CONTENTS0[] = "abcdefgh";
	const char CONTENTS1[] = "ijklmnop";
	uint64_t ino = 42;
	int fd;
	ssize_t bufsize = strlen(CONTENTS0) + 1;
	ssize_t fsize = 2 * m_maxbcachebuf;
	char readbuf[bufsize];
	void *zeros;

	zeros = calloc(1, m_maxbcachebuf);
	ASSERT_NE(nullptr, zeros);

	expect_lookup(RELPATH, ino, fsize);
	expect_open(ino, 0, 1);
	expect_read(ino, 0, m_maxbcachebuf, m_maxbcachebuf, zeros);
	FuseTest::expect_write(ino, m_maxbcachebuf, bufsize, bufsize, 0, 0,
		CONTENTS1);

	fd = open(FULLPATH, O_RDWR);
	EXPECT_LE(0, fd) << strerror(errno);

	// Cache first block with dirty data.  This will entail first reading
	// the existing data.
	ASSERT_EQ(bufsize, pwrite(fd, CONTENTS0, bufsize, 0))
		<< strerror(errno);

	// Write directly to second block
	ASSERT_EQ(0, fcntl(fd, F_SETFL, O_DIRECT)) << strerror(errno);
	ASSERT_EQ(bufsize, pwrite(fd, CONTENTS1, bufsize, m_maxbcachebuf))
		<< strerror(errno);

	// Read from the first block again.  Should be serviced by cache.
	ASSERT_EQ(0, fcntl(fd, F_SETFL, 0)) << strerror(errno);
	ASSERT_EQ(bufsize, pread(fd, readbuf, bufsize, 0)) << strerror(errno);
	ASSERT_STREQ(readbuf, CONTENTS0);

	leak(fd);
	free(zeros);
}

/*
 * If a direct io write partially overlaps one or two blocks of dirty cached
 * data, No dirty data should be lost.  Admittedly this is a weird test,
 * because it would be unusual to use O_DIRECT and the writeback cache.
 */
TEST_F(WriteBackAsync, direct_io_partially_overlaps_cached_block)
{
	const char FULLPATH[] = "mountpoint/some_file.txt";
	const char RELPATH[] = "some_file.txt";
	uint64_t ino = 42;
	int fd;
	off_t bs = m_maxbcachebuf;
	ssize_t fsize = 3 * bs;
	void *readbuf, *zeros, *ones, *zeroones, *onezeros;

	readbuf = malloc(bs);
	ASSERT_NE(nullptr, readbuf) << strerror(errno);
	zeros = calloc(1, 3 * bs);
	ASSERT_NE(nullptr, zeros);
	ones = calloc(1, 2 * bs);
	ASSERT_NE(nullptr, ones);
	memset(ones, 1, 2 * bs);
	zeroones = calloc(1, bs);
	ASSERT_NE(nullptr, zeroones);
	memset((uint8_t*)zeroones + bs / 2, 1, bs / 2);
	onezeros = calloc(1, bs);
	ASSERT_NE(nullptr, onezeros);
	memset(onezeros, 1, bs / 2);

	expect_lookup(RELPATH, ino, fsize);
	expect_open(ino, 0, 1);

	fd = open(FULLPATH, O_RDWR);
	EXPECT_LE(0, fd) << strerror(errno);

	/* Cache first and third blocks with dirty data.  */
	ASSERT_EQ(3 * bs, pwrite(fd, zeros, 3 * bs, 0)) << strerror(errno);

	/*
	 * Write directly to all three blocks.  The partially written blocks
	 * will be flushed because they're dirty.
	 */
	FuseTest::expect_write(ino, 0, bs, bs, 0, 0, zeros);
	FuseTest::expect_write(ino, 2 * bs, bs, bs, 0, 0, zeros);
	/* The direct write is split in two because of the m_maxwrite value */
	FuseTest::expect_write(ino,     bs / 2, bs, bs, 0, 0, ones);
	FuseTest::expect_write(ino, 3 * bs / 2, bs, bs, 0, 0, ones);
	ASSERT_EQ(0, fcntl(fd, F_SETFL, O_DIRECT)) << strerror(errno);
	ASSERT_EQ(2 * bs, pwrite(fd, ones, 2 * bs, bs / 2)) << strerror(errno);

	/*
	 * Read from both the valid and invalid portions of the first and third
	 * blocks again.  This will entail FUSE_READ operations because these
	 * blocks were invalidated by the direct write.
	 */
	expect_read(ino, 0, bs, bs, zeroones);
	expect_read(ino, 2 * bs, bs, bs, onezeros);
	ASSERT_EQ(0, fcntl(fd, F_SETFL, 0)) << strerror(errno);
	ASSERT_EQ(bs / 2, pread(fd, readbuf, bs / 2, 0)) << strerror(errno);
	EXPECT_EQ(0, memcmp(zeros, readbuf, bs / 2));
	ASSERT_EQ(bs / 2, pread(fd, readbuf, bs / 2, 5 * bs / 2))
		<< strerror(errno);
	EXPECT_EQ(0, memcmp(zeros, readbuf, bs / 2));
	ASSERT_EQ(bs / 2, pread(fd, readbuf, bs / 2, bs / 2))
		<< strerror(errno);
	EXPECT_EQ(0, memcmp(ones, readbuf, bs / 2));
	ASSERT_EQ(bs / 2, pread(fd, readbuf, bs / 2, 2 * bs))
		<< strerror(errno);
	EXPECT_EQ(0, memcmp(ones, readbuf, bs / 2));

	leak(fd);
	free(zeroones);
	free(onezeros);
	free(ones);
	free(zeros);
	free(readbuf);
}

/*
 * In WriteBack mode, writes may be cached beyond what the server thinks is the
 * EOF.  In this case, a short read at EOF should _not_ cause fusefs to update
 * the file's size.
 */
TEST_F(WriteBackAsync, eof)
{
	const char FULLPATH[] = "mountpoint/some_file.txt";
	const char RELPATH[] = "some_file.txt";
	const char *CONTENTS0 = "abcdefgh";
	const char *CONTENTS1 = "ijklmnop";
	uint64_t ino = 42;
	int fd;
	off_t offset = m_maxbcachebuf;
	ssize_t wbufsize = strlen(CONTENTS1);
	off_t old_filesize = (off_t)strlen(CONTENTS0);
	ssize_t rbufsize = 2 * old_filesize;
	char readbuf[rbufsize];
	size_t holesize = rbufsize - old_filesize;
	char hole[holesize];
	struct stat sb;
	ssize_t r;

	expect_lookup(RELPATH, ino, 0);
	expect_open(ino, 0, 1);
	expect_read(ino, 0, m_maxbcachebuf, old_filesize, CONTENTS0);

	fd = open(FULLPATH, O_RDWR);
	EXPECT_LE(0, fd) << strerror(errno);

	/* Write and cache data beyond EOF */
	ASSERT_EQ(wbufsize, pwrite(fd, CONTENTS1, wbufsize, offset))
		<< strerror(errno);

	/* Read from the old EOF */
	r = pread(fd, readbuf, rbufsize, 0);
	ASSERT_LE(0, r) << strerror(errno);
	EXPECT_EQ(rbufsize, r) << "read should've synthesized a hole";
	EXPECT_EQ(0, memcmp(CONTENTS0, readbuf, old_filesize));
	bzero(hole, holesize);
	EXPECT_EQ(0, memcmp(hole, readbuf + old_filesize, holesize));

	/* The file's size should still be what was established by pwrite */
	ASSERT_EQ(0, fstat(fd, &sb)) << strerror(errno);
	EXPECT_EQ(offset + wbufsize, sb.st_size);
	leak(fd);
}

/*
 * When a file has dirty writes that haven't been flushed, the server's notion
 * of its mtime and ctime will be wrong.  The kernel should ignore those if it
 * gets them from a FUSE_GETATTR before flushing.
 */
TEST_F(WriteBackAsync, timestamps)
{
	const char FULLPATH[] = "mountpoint/some_file.txt";
	const char RELPATH[] = "some_file.txt";
	const char *CONTENTS = "abcdefgh";
	ssize_t bufsize = strlen(CONTENTS);
	uint64_t ino = 42;
	uint64_t attr_valid = 0;
	uint64_t attr_valid_nsec = 0;
	uint64_t server_time = 12345;
	mode_t mode = S_IFREG | 0644;
	int fd;

	struct stat sb;

	EXPECT_LOOKUP(FUSE_ROOT_ID, RELPATH)
	.WillRepeatedly(Invoke(
		ReturnImmediate([=](auto in __unused, auto& out) {
		SET_OUT_HEADER_LEN(out, entry);
		out.body.entry.attr.mode = mode;
		out.body.entry.nodeid = ino;
		out.body.entry.attr.nlink = 1;
		out.body.entry.attr_valid = attr_valid;
		out.body.entry.attr_valid_nsec = attr_valid_nsec;
	})));
	expect_open(ino, 0, 1);
	EXPECT_CALL(*m_mock, process(
		ResultOf([=](auto in) {
			return (in.header.opcode == FUSE_GETATTR &&
				in.header.nodeid == ino);
		}, Eq(true)),
		_)
	).WillRepeatedly(Invoke(
	ReturnImmediate([=](auto i __unused, auto& out) {
		SET_OUT_HEADER_LEN(out, attr);
		out.body.attr.attr.ino = ino;
		out.body.attr.attr.mode = mode;
		out.body.attr.attr_valid = attr_valid;
		out.body.attr.attr_valid_nsec = attr_valid_nsec;
		out.body.attr.attr.atime = server_time;
		out.body.attr.attr.mtime = server_time;
		out.body.attr.attr.ctime = server_time;
	})));

	fd = open(FULLPATH, O_RDWR);
	EXPECT_LE(0, fd) << strerror(errno);
	ASSERT_EQ(bufsize, write(fd, CONTENTS, bufsize)) << strerror(errno);

	ASSERT_EQ(0, fstat(fd, &sb)) << strerror(errno);
	EXPECT_EQ((time_t)server_time, sb.st_atime);
	EXPECT_NE((time_t)server_time, sb.st_mtime);
	EXPECT_NE((time_t)server_time, sb.st_ctime);

	leak(fd);
}

/* Any dirty timestamp fields should be flushed during a SETATTR */
TEST_F(WriteBackAsync, timestamps_during_setattr)
{
	const char FULLPATH[] = "mountpoint/some_file.txt";
	const char RELPATH[] = "some_file.txt";
	const char *CONTENTS = "abcdefgh";
	ssize_t bufsize = strlen(CONTENTS);
	uint64_t ino = 42;
	const mode_t newmode = 0755;
	int fd;

	expect_lookup(RELPATH, ino, 0);
	expect_open(ino, 0, 1);
	EXPECT_CALL(*m_mock, process(
		ResultOf([=](auto in) {
			uint32_t valid = FATTR_MODE | FATTR_MTIME | FATTR_CTIME;
			return (in.header.opcode == FUSE_SETATTR &&
				in.header.nodeid == ino &&
				in.body.setattr.valid == valid);
		}, Eq(true)),
		_)
	).WillOnce(Invoke(ReturnImmediate([=](auto in __unused, auto& out) {
		SET_OUT_HEADER_LEN(out, attr);
		out.body.attr.attr.ino = ino;
		out.body.attr.attr.mode = S_IFREG | newmode;
	})));

	fd = open(FULLPATH, O_RDWR);
	EXPECT_LE(0, fd) << strerror(errno);
	ASSERT_EQ(bufsize, write(fd, CONTENTS, bufsize)) << strerror(errno);
	ASSERT_EQ(0, fchmod(fd, newmode)) << strerror(errno);

	leak(fd);
}

/* fuse_init_out.time_gran controls the granularity of timestamps */
TEST_P(TimeGran, timestamps_during_setattr)
{
	const char FULLPATH[] = "mountpoint/some_file.txt";
	const char RELPATH[] = "some_file.txt";
	const char *CONTENTS = "abcdefgh";
	ssize_t bufsize = strlen(CONTENTS);
	uint64_t ino = 42;
	const mode_t newmode = 0755;
	int fd;

	expect_lookup(RELPATH, ino, 0);
	expect_open(ino, 0, 1);
	EXPECT_CALL(*m_mock, process(
		ResultOf([=](auto in) {
			uint32_t valid = FATTR_MODE | FATTR_MTIME | FATTR_CTIME;
			return (in.header.opcode == FUSE_SETATTR &&
				in.header.nodeid == ino &&
				in.body.setattr.valid == valid &&
				in.body.setattr.mtimensec % m_time_gran == 0 &&
				in.body.setattr.ctimensec % m_time_gran == 0);
		}, Eq(true)),
		_)
	).WillOnce(Invoke(ReturnImmediate([=](auto in __unused, auto& out) {
		SET_OUT_HEADER_LEN(out, attr);
		out.body.attr.attr.ino = ino;
		out.body.attr.attr.mode = S_IFREG | newmode;
	})));

	fd = open(FULLPATH, O_RDWR);
	EXPECT_LE(0, fd) << strerror(errno);
	ASSERT_EQ(bufsize, write(fd, CONTENTS, bufsize)) << strerror(errno);
	ASSERT_EQ(0, fchmod(fd, newmode)) << strerror(errno);

	leak(fd);
}

INSTANTIATE_TEST_CASE_P(RA, TimeGran, Range(0u, 10u));

/*
 * Without direct_io, writes should be committed to cache
 */
TEST_F(Write, writethrough)
{
	const char FULLPATH[] = "mountpoint/some_file.txt";
	const char RELPATH[] = "some_file.txt";
	const char *CONTENTS = "abcdefgh";
	uint64_t ino = 42;
	int fd;
	ssize_t bufsize = strlen(CONTENTS);
	uint8_t readbuf[bufsize];

	expect_lookup(RELPATH, ino, 0);
	expect_open(ino, 0, 1);
	expect_write(ino, 0, bufsize, bufsize, CONTENTS);

	fd = open(FULLPATH, O_RDWR);
	EXPECT_LE(0, fd) << strerror(errno);

	ASSERT_EQ(bufsize, write(fd, CONTENTS, bufsize)) << strerror(errno);
	/*
	 * A subsequent read should be serviced by cache, without querying the
	 * filesystem daemon
	 */
	ASSERT_EQ(0, lseek(fd, 0, SEEK_SET)) << strerror(errno);
	ASSERT_EQ(bufsize, read(fd, readbuf, bufsize)) << strerror(errno);
	leak(fd);
}

/* Writes that extend a file should update the cached file size */
TEST_F(Write, update_file_size)
{
	const char FULLPATH[] = "mountpoint/some_file.txt";
	const char RELPATH[] = "some_file.txt";
	const char *CONTENTS = "abcdefgh";
	struct stat sb;
	uint64_t ino = 42;
	int fd;
	ssize_t bufsize = strlen(CONTENTS);

	expect_lookup(RELPATH, ino, 0);
	expect_open(ino, 0, 1);
	expect_write(ino, 0, bufsize, bufsize, CONTENTS);

	fd = open(FULLPATH, O_RDWR);
	EXPECT_LE(0, fd) << strerror(errno);

	ASSERT_EQ(bufsize, write(fd, CONTENTS, bufsize)) << strerror(errno);
	/* Get cached attributes */
	ASSERT_EQ(0, fstat(fd, &sb)) << strerror(errno);
	ASSERT_EQ(bufsize, sb.st_size);
	leak(fd);
}