git: eccfee8330e8 - stable/13 - fusefs: implement VOP_ALLOCATE

From: Alan Somers <asomers_at_FreeBSD.org>
Date: Tue, 18 Jan 2022 01:17:34 UTC
The branch stable/13 has been updated by asomers:

URL: https://cgit.FreeBSD.org/src/commit/?id=eccfee8330e8927eafaf543dd630500b3b2c9c03

commit eccfee8330e8927eafaf543dd630500b3b2c9c03
Author:     Alan Somers <asomers@FreeBSD.org>
AuthorDate: 2022-01-01 04:04:12 +0000
Commit:     Alan Somers <asomers@FreeBSD.org>
CommitDate: 2022-01-18 01:13:28 +0000

    fusefs: implement VOP_ALLOCATE
    
    Now posix_fallocate will be correctly forwarded to fuse file system
    servers, for those that support it.
    
    Reviewed by:    pfg
    Differential Revision: https://reviews.freebsd.org/D33389
    
    (cherry picked from commit 398c88c7582a195cbfeb689ceff1400cc717673f)
---
 sys/fs/fuse/fuse_internal.c                |   4 +
 sys/fs/fuse/fuse_ipc.c                     |   4 +
 sys/fs/fuse/fuse_vnops.c                   |  93 ++++++++-
 tests/sys/fs/fusefs/Makefile               |   1 +
 tests/sys/fs/fusefs/default_permissions.cc |  89 ++++++++-
 tests/sys/fs/fusefs/fallocate.cc           | 297 +++++++++++++++++++++++++++++
 tests/sys/fs/fusefs/last_local_modify.cc   |  93 ++++++---
 tests/sys/fs/fusefs/mockfs.cc              |  13 +-
 tests/sys/fs/fusefs/mockfs.hh              |   1 +
 tests/sys/fs/fusefs/utils.cc               |  17 ++
 tests/sys/fs/fusefs/utils.hh               |   8 +
 11 files changed, 593 insertions(+), 27 deletions(-)

diff --git a/sys/fs/fuse/fuse_internal.c b/sys/fs/fuse/fuse_internal.c
index 218d072566ac..846d94a81759 100644
--- a/sys/fs/fuse/fuse_internal.c
+++ b/sys/fs/fuse/fuse_internal.c
@@ -1075,6 +1075,10 @@ fuse_internal_init_callback(struct fuse_ticket *tick, struct uio *uio)
 		fsess_set_notimpl(data->mp, FUSE_DESTROY);
 	}
 
+	if (!fuse_libabi_geq(data, 7, 19)) {
+		fsess_set_notimpl(data->mp, FUSE_FALLOCATE);
+	}
+
 	if (fuse_libabi_geq(data, 7, 23) && fiio->time_gran >= 1 &&
 	    fiio->time_gran <= 1000000000)
 		data->time_gran = fiio->time_gran;
diff --git a/sys/fs/fuse/fuse_ipc.c b/sys/fs/fuse/fuse_ipc.c
index 0042de602739..7a6c0e3da76b 100644
--- a/sys/fs/fuse/fuse_ipc.c
+++ b/sys/fs/fuse/fuse_ipc.c
@@ -845,6 +845,10 @@ fuse_body_audit(struct fuse_ticket *ftick, size_t blen)
 		err = (blen == 0) ? 0 : EINVAL;
 		break;
 
+	case FUSE_FALLOCATE:
+		err = (blen == 0) ? 0 : EINVAL;
+		break;
+
 	case FUSE_LSEEK:
 		err = (blen == sizeof(struct fuse_lseek_out)) ? 0 : EINVAL;
 		break;
diff --git a/sys/fs/fuse/fuse_vnops.c b/sys/fs/fuse/fuse_vnops.c
index f57f376e5685..1fcc888d8169 100644
--- a/sys/fs/fuse/fuse_vnops.c
+++ b/sys/fs/fuse/fuse_vnops.c
@@ -127,6 +127,7 @@ SDT_PROBE_DEFINE2(fusefs, , vnops, trace, "int", "char*");
 /* vnode ops */
 static vop_access_t fuse_vnop_access;
 static vop_advlock_t fuse_vnop_advlock;
+static vop_allocate_t fuse_vnop_allocate;
 static vop_bmap_t fuse_vnop_bmap;
 static vop_close_t fuse_fifo_close;
 static vop_close_t fuse_vnop_close;
@@ -180,7 +181,7 @@ struct vop_vector fuse_fifoops = {
 VFS_VOP_VECTOR_REGISTER(fuse_fifoops);
 
 struct vop_vector fuse_vnops = {
-	.vop_allocate =	VOP_EINVAL,
+	.vop_allocate =	fuse_vnop_allocate,
 	.vop_default = &default_vnodeops,
 	.vop_access = fuse_vnop_access,
 	.vop_advlock = fuse_vnop_advlock,
@@ -550,6 +551,96 @@ out:
 	return err;
 }
 
+static int
+fuse_vnop_allocate(struct vop_allocate_args *ap)
+{
+	struct vnode *vp = ap->a_vp;
+	off_t *len = ap->a_len;
+	off_t *offset = ap->a_offset;
+	struct ucred *cred = ap->a_cred;
+	struct fuse_filehandle *fufh;
+	struct mount *mp = vnode_mount(vp);
+	struct fuse_dispatcher fdi;
+	struct fuse_fallocate_in *ffi;
+	struct uio io;
+	pid_t pid = curthread->td_proc->p_pid;
+	struct fuse_vnode_data *fvdat = VTOFUD(vp);
+	off_t filesize;
+	int err;
+
+	if (fuse_isdeadfs(vp))
+		return (ENXIO);
+
+	switch (vp->v_type) {
+	case VFIFO:
+		return (ESPIPE);
+	case VLNK:
+	case VREG:
+		if (vfs_isrdonly(mp))
+			return (EROFS);
+		break;
+	default:
+		return (ENODEV);
+	}
+
+	if (vfs_isrdonly(mp))
+		return (EROFS);
+
+	if (fsess_not_impl(mp, FUSE_FALLOCATE))
+		return (EINVAL);
+
+	io.uio_offset = *offset;
+	io.uio_resid = *len;
+	err = vn_rlimit_fsize(vp, &io, curthread);
+	if (err)
+		return (err);
+
+	err = fuse_filehandle_getrw(vp, FWRITE, &fufh, cred, pid);
+	if (err)
+		return (err);
+
+	fuse_vnode_update(vp, FN_MTIMECHANGE | FN_CTIMECHANGE);
+
+	err = fuse_vnode_size(vp, &filesize, cred, curthread);
+	if (err)
+		return (err);
+	fuse_inval_buf_range(vp, filesize, *offset, *offset + *len);
+
+	fdisp_init(&fdi, sizeof(*ffi));
+	fdisp_make_vp(&fdi, FUSE_FALLOCATE, vp, curthread, cred);
+	ffi = fdi.indata;
+	ffi->fh = fufh->fh_id;
+	ffi->offset = *offset;
+	ffi->length = *len;
+	ffi->mode = 0;
+	err = fdisp_wait_answ(&fdi);
+
+	if (err == ENOSYS) {
+		fsess_set_notimpl(mp, FUSE_FALLOCATE);
+		err = EINVAL;
+	} else if (err == EOPNOTSUPP) {
+		/*
+		 * The file system server does not support FUSE_FALLOCATE with
+		 * the supplied mode.  That's effectively the same thing as
+		 * ENOSYS since we only ever issue mode=0.
+		 * TODO: revise this section once we support fspacectl.
+		 */
+		fsess_set_notimpl(mp, FUSE_FALLOCATE);
+		err = EINVAL;
+	} else if (!err) {
+		*offset += *len;
+		*len = 0;
+		fuse_vnode_undirty_cached_timestamps(vp, false);
+		fuse_internal_clear_suid_on_write(vp, cred, curthread);
+		if (*offset > fvdat->cached_attrs.va_size) {
+			fuse_vnode_setsize(vp, *offset, false);
+			getnanouptime(&fvdat->last_local_modify);
+		}
+	}
+
+	return (err);
+}
+
 /* {
 	struct vnode *a_vp;
 	daddr_t a_bn;
diff --git a/tests/sys/fs/fusefs/Makefile b/tests/sys/fs/fusefs/Makefile
index e508d3edbdea..04b68681ec9a 100644
--- a/tests/sys/fs/fusefs/Makefile
+++ b/tests/sys/fs/fusefs/Makefile
@@ -19,6 +19,7 @@ GTESTS+=	default_permissions
 GTESTS+=	default_permissions_privileged
 GTESTS+=	destroy
 GTESTS+=	dev_fuse_poll
+GTESTS+=	fallocate
 GTESTS+=	fifo
 GTESTS+=	flush
 GTESTS+=	forget
diff --git a/tests/sys/fs/fusefs/default_permissions.cc b/tests/sys/fs/fusefs/default_permissions.cc
index 6401f926bb49..0739ad48f1e2 100644
--- a/tests/sys/fs/fusefs/default_permissions.cc
+++ b/tests/sys/fs/fusefs/default_permissions.cc
@@ -163,6 +163,7 @@ class Chgrp: public DefaultPermissions {};
 class CopyFileRange: public DefaultPermissions {};
 class Lookup: public DefaultPermissions {};
 class Open: public DefaultPermissions {};
+class PosixFallocate: public DefaultPermissions {};
 class Setattr: public DefaultPermissions {};
 class Unlink: public DefaultPermissions {};
 class Utimensat: public DefaultPermissions {};
@@ -498,7 +499,7 @@ TEST_F(Chgrp, ok)
 }
 
 /* A write by a non-owner should clear a file's SGID bit */
-TEST_F(CopyFileRange, clear_guid)
+TEST_F(CopyFileRange, clear_sgid)
 {
 	const char FULLPATH_IN[] = "mountpoint/in.txt";
 	const char RELPATH_IN[] = "in.txt";
@@ -877,6 +878,92 @@ TEST_F(Open, ok)
 	leak(fd);
 }
 
+/* A write by a non-owner should clear a file's SGID bit */
+TEST_F(PosixFallocate, clear_sgid)
+{
+	const char FULLPATH[] = "mountpoint/file.txt";
+	const char RELPATH[] = "file.txt";
+	struct stat sb;
+	uint64_t ino = 42;
+	mode_t oldmode = 02777;
+	mode_t newmode = 0777;
+	off_t fsize = 16;
+	off_t off = 8;
+	off_t len = 8;
+	int fd;
+
+	expect_getattr(FUSE_ROOT_ID, S_IFDIR | 0755, UINT64_MAX, 1);
+	FuseTest::expect_lookup(RELPATH, ino, S_IFREG | oldmode, fsize,
+	    1, UINT64_MAX, 0, 0);
+	expect_open(ino, 0, 1);
+	expect_fallocate(ino, off, len, 0, 0);
+	expect_chmod(ino, newmode, fsize);
+
+	fd = open(FULLPATH, O_WRONLY);
+	ASSERT_LE(0, fd) << strerror(errno);
+	EXPECT_EQ(0, posix_fallocate(fd, off, len)) << strerror(errno);
+	ASSERT_EQ(0, fstat(fd, &sb)) << strerror(errno);
+	EXPECT_EQ(S_IFREG | newmode, sb.st_mode);
+
+	leak(fd);
+}
+
+/* A write by a non-owner should clear a file's SUID bit */
+TEST_F(PosixFallocate, clear_suid)
+{
+	const char FULLPATH[] = "mountpoint/file.txt";
+	const char RELPATH[] = "file.txt";
+	struct stat sb;
+	uint64_t ino = 42;
+	mode_t oldmode = 04777;
+	mode_t newmode = 0777;
+	off_t fsize = 16;
+	off_t off = 8;
+	off_t len = 8;
+	int fd;
+
+	expect_getattr(FUSE_ROOT_ID, S_IFDIR | 0755, UINT64_MAX, 1);
+	FuseTest::expect_lookup(RELPATH, ino, S_IFREG | oldmode, fsize,
+	    1, UINT64_MAX, 0, 0);
+	expect_open(ino, 0, 1);
+	expect_fallocate(ino, off, len, 0, 0);
+	expect_chmod(ino, newmode, fsize);
+
+	fd = open(FULLPATH, O_WRONLY);
+	ASSERT_LE(0, fd) << strerror(errno);
+	EXPECT_EQ(0, posix_fallocate(fd, off, len)) << strerror(errno);
+	ASSERT_EQ(0, fstat(fd, &sb)) << strerror(errno);
+	EXPECT_EQ(S_IFREG | newmode, sb.st_mode);
+
+	leak(fd);
+}
+
+/*
+ * posix_fallcoate() of a file without writable permissions should succeed as
+ * long as the file descriptor is writable.  This is important when combined
+ * with O_CREAT
+ */
+TEST_F(PosixFallocate, posix_fallocate_of_newly_created_file)
+{
+	const char FULLPATH[] = "mountpoint/some_file.txt";
+	const char RELPATH[] = "some_file.txt";
+	const uint64_t ino = 42;
+	off_t off = 8;
+	off_t len = 8;
+	int fd;
+
+	expect_getattr(FUSE_ROOT_ID, S_IFDIR | 0777, UINT64_MAX, 1);
+	EXPECT_LOOKUP(FUSE_ROOT_ID, RELPATH)
+		.WillOnce(Invoke(ReturnErrno(ENOENT)));
+	expect_create(RELPATH, ino);
+	expect_fallocate(ino, off, len, 0, 0);
+
+	fd = open(FULLPATH, O_CREAT | O_RDWR, 0);
+	ASSERT_LE(0, fd) << strerror(errno);
+	EXPECT_EQ(0, posix_fallocate(fd, off, len)) << strerror(errno);
+	leak(fd);
+}
+
 TEST_F(Rename, eacces_on_srcdir)
 {
 	const char FULLDST[] = "mountpoint/d/dst";
diff --git a/tests/sys/fs/fusefs/fallocate.cc b/tests/sys/fs/fusefs/fallocate.cc
new file mode 100644
index 000000000000..386a3ac746ea
--- /dev/null
+++ b/tests/sys/fs/fusefs/fallocate.cc
@@ -0,0 +1,297 @@
+/*-
+ * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
+ *
+ * Copyright (c) 2021 Alan Somers
+ *
+ * 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/mount.h>
+#include <sys/resource.h>
+#include <sys/time.h>
+
+#include <fcntl.h>
+#include <signal.h>
+#include <unistd.h>
+
+#include "mntopts.h"	// for build_iovec
+}
+
+#include "mockfs.hh"
+#include "utils.hh"
+
+using namespace testing;
+
+class Fallocate: public FuseTest{};
+
+class PosixFallocate: public Fallocate {
+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);
+
+	Fallocate::TearDown();
+}
+
+};
+
+sig_atomic_t PosixFallocate::s_sigxfsz = 0;
+
+void sigxfsz_handler(int __unused sig) {
+	PosixFallocate::s_sigxfsz = 1;
+}
+
+class PosixFallocate_7_18: public PosixFallocate {
+public:
+virtual void SetUp() {
+	m_kernel_minor_version = 18;
+	PosixFallocate::SetUp();
+}
+};
+
+
+/*
+ * If the server returns ENOSYS, it indicates that the server does not support
+ * FUSE_FALLOCATE.  This and future calls should return EINVAL.
+ */
+TEST_F(PosixFallocate, enosys)
+{
+	const char FULLPATH[] = "mountpoint/some_file.txt";
+	const char RELPATH[] = "some_file.txt";
+	uint64_t ino = 42;
+	uint64_t offset = 0;
+	uint64_t length = 1000;
+	int fd;
+
+	expect_lookup(RELPATH, ino, S_IFREG | 0644, 0, 1);
+	expect_open(ino, 0, 1);
+	expect_fallocate(ino, offset, length, 0, ENOSYS);
+
+	fd = open(FULLPATH, O_RDWR);
+	ASSERT_LE(0, fd) << strerror(errno);
+	EXPECT_EQ(EINVAL, posix_fallocate(fd, offset, length));
+
+	/* Subsequent calls shouldn't query the daemon*/
+	EXPECT_EQ(EINVAL, posix_fallocate(fd, offset, length));
+
+	leak(fd);
+}
+
+/*
+ * EOPNOTSUPP means either "the file system does not support fallocate" or "the
+ * file system does not support fallocate with the supplied mode".  fusefs
+ * should conservatively assume the latter, and not issue any more fallocate
+ * operations with the same mode.
+ */
+TEST_F(PosixFallocate, eopnotsupp)
+{
+	const char FULLPATH[] = "mountpoint/some_file.txt";
+	const char RELPATH[] = "some_file.txt";
+	uint64_t ino = 42;
+	uint64_t offset = 0;
+	uint64_t length = 1000;
+	int fd;
+
+	expect_lookup(RELPATH, ino, S_IFREG | 0644, 0, 1);
+	expect_open(ino, 0, 1);
+	expect_fallocate(ino, offset, length, 0, EOPNOTSUPP);
+
+	fd = open(FULLPATH, O_RDWR);
+	ASSERT_LE(0, fd) << strerror(errno);
+	EXPECT_EQ(EINVAL, posix_fallocate(fd, offset, length));
+
+	/* Subsequent calls shouldn't query the daemon*/
+	EXPECT_EQ(EINVAL, posix_fallocate(fd, offset, length));
+
+	leak(fd);
+}
+
+/* EIO is not a permanent error, and may be retried */
+TEST_F(PosixFallocate, eio)
+{
+	const char FULLPATH[] = "mountpoint/some_file.txt";
+	const char RELPATH[] = "some_file.txt";
+	uint64_t ino = 42;
+	uint64_t offset = 0;
+	uint64_t length = 1000;
+	int fd;
+
+	expect_lookup(RELPATH, ino, S_IFREG | 0644, 0, 1);
+	expect_open(ino, 0, 1);
+	expect_fallocate(ino, offset, length, 0, EIO);
+
+	fd = open(FULLPATH, O_RDWR);
+	ASSERT_LE(0, fd) << strerror(errno);
+	EXPECT_EQ(EIO, posix_fallocate(fd, offset, length));
+
+	expect_fallocate(ino, offset, length, 0, 0);
+
+	EXPECT_EQ(0, posix_fallocate(fd, offset, length));
+
+	leak(fd);
+}
+
+TEST_F(PosixFallocate, erofs)
+{
+	const char FULLPATH[] = "mountpoint/some_file.txt";
+	const char RELPATH[] = "some_file.txt";
+	struct statfs statbuf;
+	struct iovec *iov = NULL;
+	int iovlen = 0;
+	uint64_t ino = 42;
+	uint64_t offset = 0;
+	uint64_t length = 1000;
+	int fd;
+	int newflags;
+
+	expect_lookup(RELPATH, ino, S_IFREG | 0644, 0, 1);
+	expect_open(ino, 0, 1);
+	EXPECT_CALL(*m_mock, process(
+		ResultOf([](auto in) {
+			return (in.header.opcode == FUSE_STATFS);
+		}, Eq(true)),
+		_)
+	).WillRepeatedly(Invoke(ReturnImmediate([=](auto in __unused, auto& out)
+	{
+		/*
+		 * All of the fields except f_flags are don't care, and f_flags
+		 * is set by the VFS
+		 */
+		SET_OUT_HEADER_LEN(out, statfs);
+	})));
+
+	fd = open(FULLPATH, O_RDWR);
+	ASSERT_LE(0, fd) << strerror(errno);
+
+	/* Remount read-only */
+	ASSERT_EQ(0, statfs("mountpoint", &statbuf)) << strerror(errno);
+	newflags = statbuf.f_flags | MNT_UPDATE | MNT_RDONLY;
+	build_iovec(&iov, &iovlen, "fstype", (void*)statbuf.f_fstypename, -1);
+	build_iovec(&iov, &iovlen, "fspath", (void*)statbuf.f_mntonname, -1);
+	build_iovec(&iov, &iovlen, "from", __DECONST(void *, "/dev/fuse"), -1);
+	ASSERT_EQ(0, nmount(iov, iovlen, newflags)) << strerror(errno);
+
+	EXPECT_EQ(EROFS, posix_fallocate(fd, offset, length));
+
+	leak(fd);
+}
+
+TEST_F(PosixFallocate, ok)
+{
+	const char FULLPATH[] = "mountpoint/some_file.txt";
+	const char RELPATH[] = "some_file.txt";
+	struct stat sb0, sb1;
+	uint64_t ino = 42;
+	uint64_t offset = 0;
+	uint64_t length = 1000;
+	int fd;
+
+	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 = ino;
+		out.body.entry.entry_valid = UINT64_MAX;
+		out.body.entry.attr_valid = UINT64_MAX;
+	})));
+	expect_open(ino, 0, 1);
+	expect_fallocate(ino, offset, length, 0, 0);
+
+	fd = open(FULLPATH, O_RDWR);
+	ASSERT_LE(0, fd) << strerror(errno);
+	ASSERT_EQ(0, fstat(fd, &sb0)) << strerror(errno);
+	EXPECT_EQ(0, posix_fallocate(fd, offset, length));
+	/*
+	 * Despite the originally cached file size of zero, stat should now
+	 * return either the new size or requery the daemon.
+	 */
+	EXPECT_EQ(0, stat(FULLPATH, &sb1));
+	EXPECT_EQ(length, (uint64_t)sb1.st_size);
+
+	/* mtime and ctime should be updated */
+	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);
+}
+
+/* fusefs should respect RLIMIT_FSIZE */
+TEST_F(PosixFallocate, rlimit_fsize)
+{
+	const char FULLPATH[] = "mountpoint/some_file.txt";
+	const char RELPATH[] = "some_file.txt";
+	struct rlimit rl;
+	uint64_t ino = 42;
+	uint64_t offset = 0;
+	uint64_t length = 1'000'000;
+	int fd;
+
+	expect_lookup(RELPATH, ino, S_IFREG | 0644, 0, 1);
+	expect_open(ino, 0, 1);
+
+	rl.rlim_cur = length / 2;
+	rl.rlim_max = 10 * length;
+	ASSERT_EQ(0, setrlimit(RLIMIT_FSIZE, &rl)) << strerror(errno);
+	ASSERT_NE(SIG_ERR, signal(SIGXFSZ, sigxfsz_handler)) << strerror(errno);
+
+	fd = open(FULLPATH, O_RDWR);
+	ASSERT_LE(0, fd) << strerror(errno);
+	EXPECT_EQ(EFBIG, posix_fallocate(fd, offset, length));
+	EXPECT_EQ(1, s_sigxfsz);
+
+	leak(fd);
+}
+
+/* With older servers, no FUSE_FALLOCATE should be attempted */
+TEST_F(PosixFallocate_7_18, einval)
+{
+	const char FULLPATH[] = "mountpoint/some_file.txt";
+	const char RELPATH[] = "some_file.txt";
+	uint64_t ino = 42;
+	uint64_t offset = 0;
+	uint64_t length = 1000;
+	int fd;
+
+	expect_lookup(RELPATH, ino, S_IFREG | 0644, 0, 1);
+	expect_open(ino, 0, 1);
+
+	fd = open(FULLPATH, O_RDWR);
+	ASSERT_LE(0, fd) << strerror(errno);
+	EXPECT_EQ(EINVAL, posix_fallocate(fd, offset, length));
+
+	leak(fd);
+}
diff --git a/tests/sys/fs/fusefs/last_local_modify.cc b/tests/sys/fs/fusefs/last_local_modify.cc
index a203a02e922b..9826296c80c3 100644
--- a/tests/sys/fs/fusefs/last_local_modify.cc
+++ b/tests/sys/fs/fusefs/last_local_modify.cc
@@ -62,9 +62,10 @@ using namespace testing;
  */
 
 enum Mutator {
+	VOP_ALLOCATE,
+	VOP_COPY_FILE_RANGE,
 	VOP_SETATTR,
 	VOP_WRITE,
-	VOP_COPY_FILE_RANGE
 };
 
 /*
@@ -73,22 +74,26 @@ enum Mutator {
  * --gtest_list_tests
  */
 enum Mutator writer_from_str(const char* s) {
-	if (0 == strcmp("VOP_SETATTR", s))
+	if (0 == strcmp("VOP_ALLOCATE", s))
+		return VOP_ALLOCATE;
+	else if (0 == strcmp("VOP_COPY_FILE_RANGE", s))
+		return VOP_COPY_FILE_RANGE;
+	else if (0 == strcmp("VOP_SETATTR", s))
 		return VOP_SETATTR;
-	else if (0 == strcmp("VOP_WRITE", s))
-		return VOP_WRITE;
 	else
-		return VOP_COPY_FILE_RANGE;
+		return VOP_WRITE;
 }
 
 uint32_t fuse_op_from_mutator(enum Mutator mutator) {
 	switch(mutator) {
+	case VOP_ALLOCATE:
+		return(FUSE_FALLOCATE);
+	case VOP_COPY_FILE_RANGE:
+		return(FUSE_COPY_FILE_RANGE);
 	case VOP_SETATTR:
 		return(FUSE_SETATTR);
 	case VOP_WRITE:
 		return(FUSE_WRITE);
-	case VOP_COPY_FILE_RANGE:
-		return(FUSE_COPY_FILE_RANGE);
 	}
 }
 
@@ -101,6 +106,25 @@ virtual void SetUp() {
 }
 };
 
+static void* allocate_th(void* arg) {
+	int fd;
+	ssize_t r;
+	sem_t *sem = (sem_t*) arg;
+
+	if (sem)
+		sem_wait(sem);
+
+	fd = open("mountpoint/some_file.txt", O_RDWR);
+	if (fd < 0)
+		return (void*)(intptr_t)errno;
+
+	r = posix_fallocate(fd, 0, 15);
+	if (r >= 0)
+		return 0;
+	else
+		return (void*)(intptr_t)errno;
+}
+
 static void* copy_file_range_th(void* arg) {
 	ssize_t r;
 	int fd;
@@ -261,6 +285,14 @@ TEST_P(LastLocalModify, lookup)
 		/* Then, respond to the mutator request */
 		out1->header.unique = mutator_unique;
 		switch(mutator) {
+		case VOP_ALLOCATE:
+			out1->header.error = 0;
+			out1->header.len = sizeof(out1->header);
+			break;
+		case VOP_COPY_FILE_RANGE:
+			SET_OUT_HEADER_LEN(*out1, write);
+			out1->body.write.size = mutator_size;
+			break;
 		case VOP_SETATTR:
 			SET_OUT_HEADER_LEN(*out1, attr);
 			out1->body.attr.attr.ino = ino;
@@ -272,16 +304,20 @@ TEST_P(LastLocalModify, lookup)
 			SET_OUT_HEADER_LEN(*out1, write);
 			out1->body.write.size = mutator_size;
 			break;
-		case VOP_COPY_FILE_RANGE:
-			SET_OUT_HEADER_LEN(*out1, write);
-			out1->body.write.size = mutator_size;
-			break;
 		}
 		out.push_back(std::move(out1));
 	}));
 
 	/* Start the mutator thread */
 	switch(mutator) {
+	case VOP_ALLOCATE:
+		ASSERT_EQ(0, pthread_create(&th0, NULL, allocate_th,
+			NULL)) << strerror(errno);
+		break;
+	case VOP_COPY_FILE_RANGE:
+		ASSERT_EQ(0, pthread_create(&th0, NULL, copy_file_range_th,
+			NULL)) << strerror(errno);
+		break;
 	case VOP_SETATTR:
 		ASSERT_EQ(0, pthread_create(&th0, NULL, setattr_th, NULL))
 			<< strerror(errno);
@@ -290,10 +326,6 @@ TEST_P(LastLocalModify, lookup)
 		ASSERT_EQ(0, pthread_create(&th0, NULL, write_th, NULL))
 			<< strerror(errno);
 		break;
-	case VOP_COPY_FILE_RANGE:
-		ASSERT_EQ(0, pthread_create(&th0, NULL, copy_file_range_th,
-			NULL)) << strerror(errno);
-		break;
 	}
 
 
@@ -415,6 +447,14 @@ TEST_P(LastLocalModify, vfs_vget)
 		/* Then, respond to the mutator request */
 		out1->header.unique = in.header.unique;
 		switch(mutator) {
+		case VOP_ALLOCATE:
+			out1->header.error = 0;
+			out1->header.len = sizeof(out1->header);
+			break;
+		case VOP_COPY_FILE_RANGE:
+			SET_OUT_HEADER_LEN(*out1, write);
+			out1->body.write.size = in.body.copy_file_range.len;
+			break;
 		case VOP_SETATTR:
 			SET_OUT_HEADER_LEN(*out1, attr);
 			out1->body.attr.attr.ino = ino;
@@ -426,10 +466,6 @@ TEST_P(LastLocalModify, vfs_vget)
 			SET_OUT_HEADER_LEN(*out1, write);
 			out1->body.write.size = in.body.write.size;
 			break;
-		case VOP_COPY_FILE_RANGE:
-			SET_OUT_HEADER_LEN(*out1, write);
-			out1->body.write.size = in.body.copy_file_range.len;
-			break;
 		}
 		out.push_back(std::move(out1));
 	}));
@@ -439,6 +475,14 @@ TEST_P(LastLocalModify, vfs_vget)
 
 	/* Start the mutator thread */
 	switch(mutator) {
+	case VOP_ALLOCATE:
+		ASSERT_EQ(0, pthread_create(&th0, NULL, allocate_th,
+			(void*)&sem)) << strerror(errno);
+		break;
+	case VOP_COPY_FILE_RANGE:
+		ASSERT_EQ(0, pthread_create(&th0, NULL, copy_file_range_th,
+			(void*)&sem)) << strerror(errno);
+		break;
 	case VOP_SETATTR:
 		ASSERT_EQ(0, pthread_create(&th0, NULL, setattr_th,
 			(void*)&sem)) << strerror(errno);
@@ -447,10 +491,6 @@ TEST_P(LastLocalModify, vfs_vget)
 		ASSERT_EQ(0, pthread_create(&th0, NULL, write_th, (void*)&sem))
 			<< strerror(errno);
 		break;
-	case VOP_COPY_FILE_RANGE:
-		ASSERT_EQ(0, pthread_create(&th0, NULL, copy_file_range_th,
-			(void*)&sem)) << strerror(errno);
-		break;
 	}
 
 	/* Lookup again, which will race with setattr */
@@ -465,5 +505,10 @@ TEST_P(LastLocalModify, vfs_vget)
 
 
 INSTANTIATE_TEST_CASE_P(LLM, LastLocalModify,
-	Values("VOP_SETATTR", "VOP_WRITE", "VOP_COPY_FILE_RANGE")
+	Values(
+		"VOP_ALLOCATE",
+		"VOP_COPY_FILE_RANGE",
+		"VOP_SETATTR",
+		"VOP_WRITE"
+	)
 );
diff --git a/tests/sys/fs/fusefs/mockfs.cc b/tests/sys/fs/fusefs/mockfs.cc
index a943d3d6972c..231f46b18aba 100644
--- a/tests/sys/fs/fusefs/mockfs.cc
+++ b/tests/sys/fs/fusefs/mockfs.cc
@@ -207,6 +207,14 @@ void MockFS::debug_request(const mockfs_buf_in &in, ssize_t buflen)
 			printf(" flags=%#x name=%s",
 				in.body.open.flags, name);
 			break;
+		case FUSE_FALLOCATE:
+			printf(" fh=%#" PRIx64 " offset=%" PRIu64
+				" length=%" PRIx64 " mode=%#x",
+				in.body.fallocate.fh,
+				in.body.fallocate.offset,
+				in.body.fallocate.length,
+				in.body.fallocate.mode);
+			break;
 		case FUSE_FLUSH:
 			printf(" fh=%#" PRIx64 " lock_owner=%" PRIu64,
 				in.body.flush.fh,
@@ -684,6 +692,10 @@ void MockFS::audit_request(const mockfs_buf_in &in, ssize_t buflen) {
 		EXPECT_EQ(inlen, fih + sizeof(in.body.interrupt));
 		EXPECT_EQ((size_t)buflen, inlen);
 		break;
+	case FUSE_FALLOCATE:
+		EXPECT_EQ(inlen, fih + sizeof(in.body.fallocate));
+		EXPECT_EQ((size_t)buflen, inlen);
+		break;
 	case FUSE_BMAP:
 		EXPECT_EQ(inlen, fih + sizeof(in.body.bmap));
 		EXPECT_EQ((size_t)buflen, inlen);
@@ -699,7 +711,6 @@ void MockFS::audit_request(const mockfs_buf_in &in, ssize_t buflen) {
 		break;
 	case FUSE_NOTIFY_REPLY:
 	case FUSE_BATCH_FORGET:
-	case FUSE_FALLOCATE:
 	case FUSE_IOCTL:
 	case FUSE_POLL:
 	case FUSE_READDIRPLUS:
diff --git a/tests/sys/fs/fusefs/mockfs.hh b/tests/sys/fs/fusefs/mockfs.hh
index dd6d259ca5af..e35f2efb8dae 100644
--- a/tests/sys/fs/fusefs/mockfs.hh
+++ b/tests/sys/fs/fusefs/mockfs.hh
@@ -159,6 +159,7 @@ union fuse_payloads_in {
 	];
 	fuse_copy_file_range_in	copy_file_range;
 	fuse_create_in	create;
+	fuse_fallocate_in fallocate;
 	fuse_flush_in	flush;
 	fuse_fsync_in	fsync;
 	fuse_fsync_in	fsyncdir;
diff --git a/tests/sys/fs/fusefs/utils.cc b/tests/sys/fs/fusefs/utils.cc
index fb2109e1e9c4..508c3af2828f 100644
--- a/tests/sys/fs/fusefs/utils.cc
+++ b/tests/sys/fs/fusefs/utils.cc
@@ -225,6 +225,23 @@ FuseTest::expect_destroy(int error)
 	})));
 }
 
+void
+FuseTest::expect_fallocate(uint64_t ino, uint64_t offset, uint64_t length,
+	uint32_t mode, int error, int times)
+{
+	EXPECT_CALL(*m_mock, process(
+		ResultOf([=](auto in) {
+			return (in.header.opcode == FUSE_FALLOCATE &&
+				in.header.nodeid == ino &&
+				in.body.fallocate.offset == offset &&
+				in.body.fallocate.length == length &&
+				in.body.fallocate.mode == mode);
+		}, Eq(true)),
+		_)
+	).Times(times)
+	.WillRepeatedly(Invoke(ReturnErrno(error)));
+}
+
 void
 FuseTest::expect_flush(uint64_t ino, int times, ProcessMockerT r)
 {
diff --git a/tests/sys/fs/fusefs/utils.hh b/tests/sys/fs/fusefs/utils.hh
index 610d2126fa52..1cd7bad97998 100644
--- a/tests/sys/fs/fusefs/utils.hh
+++ b/tests/sys/fs/fusefs/utils.hh
@@ -114,6 +114,14 @@ class FuseTest : public ::testing::Test {
 	/* Expect FUSE_DESTROY and shutdown the daemon */
 	void expect_destroy(int error);
 
+	/*
+	 * Create an expectation that FUSE_FALLOCATE will be called with the
+	 * given inode, offset, length, and mode, exactly times times and
+	 * returning error
+	 */
+	void expect_fallocate(uint64_t ino, uint64_t offset, uint64_t length,
+		uint32_t mode, int error, int times=1);
+
 	/*
 	 * Create an expectation that FUSE_FLUSH will be called times times for
 	 * the given inode