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fusefs: Allow update mounts

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Allow "mount -u" to change some mount options for fusefs.

Sponsored by:	The FreeBSD Foundation
This commit is contained in:
Alan Somers 2019-05-21 19:34:39 +00:00
parent d5fce87d7c
commit a6fac00c53
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/projects/fuse2/; revision=348062
4 changed files with 231 additions and 17 deletions
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6
sys/fs/fuse/fuse_ipc.h
View File

@ -206,6 +206,7 @@ struct fuse_data {
int daemon_timeout;
uint64_t notimpl;
uint64_t mnt_flag;
};
#define FSESS_DEAD 0x0001 /* session is to be closed */
@ -221,6 +222,11 @@ struct fuse_data {
#define FSESS_NO_NAMECACHE 0x0400 /* disable name cache */
#define FSESS_NO_MMAP 0x0800 /* disable mmap */
#define FSESS_POSIX_LOCKS 0x2000 /* daemon supports POSIX locks */
#define FSESS_MNTOPTS_MASK ( \
FSESS_DAEMON_CAN_SPY | FSESS_PUSH_SYMLINKS_IN | \
FSESS_DEFAULT_PERMISSIONS | FSESS_NO_ATTRCACHE | \
FSESS_NO_READAHEAD | FSESS_NO_DATACACHE | \
FSESS_NO_NAMECACHE | FSESS_NO_MMAP)
enum fuse_data_cache_mode {
FUSE_CACHE_UC,

89
sys/fs/fuse/fuse_vfsops.c
View File

@ -205,6 +205,57 @@ SDT_PROBE_DEFINE1(fusefs, , vfsops, mntopts, "uint64_t");
SDT_PROBE_DEFINE4(fusefs, , vfsops, mount_err, "char*", "struct fuse_data*",
"struct mount*", "int");
static int
fuse_vfs_remount(struct mount *mp, struct thread *td, uint64_t mntopts,
uint32_t max_read, int daemon_timeout)
{
int err = 0;
struct fuse_data *data = fuse_get_mpdata(mp);
/* Don't allow these options to be changed */
const static unsigned long long cant_update_opts =
MNT_USER; /* Mount owner must be the user running the daemon */
FUSE_LOCK();
if ((mp->mnt_flag ^ data->mnt_flag) & cant_update_opts) {
err = EOPNOTSUPP;
SDT_PROBE4(fusefs, , vfsops, mount_err,
"Can't change these mount options during remount",
data, mp, err);
goto out;
}
if (((data->dataflags ^ mntopts) & FSESS_MNTOPTS_MASK) ||
(data->max_read != max_read) ||
(data->daemon_timeout != daemon_timeout)) {
// TODO: allow changing options where it makes sense
err = EOPNOTSUPP;
SDT_PROBE4(fusefs, , vfsops, mount_err,
"Can't change fuse mount options during remount",
data, mp, err);
goto out;
}
if (fdata_get_dead(data)) {
err = ENOTCONN;
SDT_PROBE4(fusefs, , vfsops, mount_err,
"device is dead during mount", data, mp, err);
goto out;
}
/* Sanity + permission checks */
if (!data->daemoncred)
panic("fuse daemon found, but identity unknown");
if (mntopts & FSESS_DAEMON_CAN_SPY)
err = priv_check(td, PRIV_VFS_FUSE_ALLOWOTHER);
if (err == 0 && td->td_ucred->cr_uid != data->daemoncred->cr_uid)
/* are we allowed to do the first mount? */
err = priv_check(td, PRIV_VFS_FUSE_MOUNT_NONUSER);
out:
FUSE_UNLOCK();
return err;
}
static int
fuse_vfsop_mount(struct mount *mp)
{
@ -231,12 +282,8 @@ fuse_vfsop_mount(struct mount *mp)
__mntopts = 0;
td = curthread;
if (mp->mnt_flag & MNT_UPDATE)
return EOPNOTSUPP;
MNT_ILOCK(mp);
mp->mnt_flag |= MNT_SYNCHRONOUS;
mp->mnt_data = NULL;
MNT_IUNLOCK(mp);
/* Get the new options passed to mount */
opts = mp->mnt_optnew;
@ -248,19 +295,6 @@ fuse_vfsop_mount(struct mount *mp)
if (!vfs_getopts(opts, "fspath", &err))
return err;
/* `from' contains the device name (eg. /dev/fuse0); REQUIRED */
fspec = vfs_getopts(opts, "from", &err);
if (!fspec)
return err;
/* `fd' contains the filedescriptor for this session; REQUIRED */
if (vfs_scanopt(opts, "fd", "%d", &fd) != 1)
return EINVAL;
err = fuse_getdevice(fspec, td, &fdev);
if (err != 0)
return err;
/*
* With the help of underscored options the mount program
* can inform us from the flags it sets by default
@ -287,6 +321,25 @@ fuse_vfsop_mount(struct mount *mp)
SDT_PROBE1(fusefs, , vfsops, mntopts, mntopts);
if (mp->mnt_flag & MNT_UPDATE) {
/*dev_rel(fdev);*/
return fuse_vfs_remount(mp, td, mntopts, max_read,
daemon_timeout);
}
/* `from' contains the device name (eg. /dev/fuse0); REQUIRED */
fspec = vfs_getopts(opts, "from", &err);
if (!fspec)
return err;
/* `fd' contains the filedescriptor for this session; REQUIRED */
if (vfs_scanopt(opts, "fd", "%d", &fd) != 1)
return EINVAL;
err = fuse_getdevice(fspec, td, &fdev);
if (err != 0)
return err;
err = fget(td, fd, &cap_read_rights, &fp);
if (err != 0) {
SDT_PROBE2(fusefs, , vfsops, trace, 1,
@ -330,6 +383,7 @@ fuse_vfsop_mount(struct mount *mp)
data->dataflags |= mntopts;
data->max_read = max_read;
data->daemon_timeout = daemon_timeout;
data->mnt_flag = mp->mnt_flag & MNT_UPDATEMASK;
FUSE_UNLOCK();
vfs_getnewfsid(mp);
@ -365,6 +419,7 @@ fuse_vfsop_mount(struct mount *mp)
SDT_PROBE4(fusefs, , vfsops, mount_err,
"mount failed, destroy device", data, mp, err);
data->mp = NULL;
mp->mnt_data = NULL;
fdata_trydestroy(data);
}
FUSE_UNLOCK();

1
tests/sys/fs/fusefs/Makefile
View File

@ -25,6 +25,7 @@ GTESTS+= locks
GTESTS+= lookup
GTESTS+= mkdir
GTESTS+= mknod
GTESTS+= mount
GTESTS+= open
GTESTS+= opendir
GTESTS+= read

152
tests/sys/fs/fusefs/mount.cc Normal file
View File

@ -0,0 +1,152 @@
/*-
* 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.
*/
extern "C" {
#include <sys/param.h>
#include <sys/mount.h>
#include <sys/uio.h>
#include "mntopts.h" // for build_iovec
}
#include "mockfs.hh"
#include "utils.hh"
using namespace testing;
class UpdateOk: public FuseTest, public WithParamInterface<const char*> {};
class UpdateErr: public FuseTest, public WithParamInterface<const char*> {};
int mntflag_from_string(const char *s)
{
if (0 == strcmp("MNT_RDONLY", s))
return MNT_RDONLY;
else if (0 == strcmp("MNT_NOEXEC", s))
return MNT_NOEXEC;
else if (0 == strcmp("MNT_NOSUID", s))
return MNT_NOSUID;
else if (0 == strcmp("MNT_NOATIME", s))
return MNT_NOATIME;
else if (0 == strcmp("MNT_SUIDDIR", s))
return MNT_SUIDDIR;
else if (0 == strcmp("MNT_USER", s))
return MNT_USER;
else
return 0;
}
/* Some mount options can be changed by mount -u */
TEST_P(UpdateOk, update)
{
struct statfs statbuf;
struct iovec *iov = NULL;
int iovlen = 0;
int flag;
int newflags = MNT_UPDATE | MNT_SYNCHRONOUS;
flag = mntflag_from_string(GetParam());
if (flag == MNT_NOSUID && 0 != geteuid())
GTEST_SKIP() << "Only root may clear MNT_NOSUID";
if (flag == MNT_SUIDDIR && 0 != geteuid())
GTEST_SKIP() << "Only root may set MNT_SUIDDIR";
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);
})));
ASSERT_EQ(0, statfs("mountpoint", &statbuf)) << strerror(errno);
newflags = (statbuf.f_flags | MNT_UPDATE) ^ flag;
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);
ASSERT_EQ(0, statfs("mountpoint", &statbuf)) << strerror(errno);
EXPECT_FALSE((newflags ^ statbuf.f_flags) & flag);
}
/* Some mount options cannnot be changed by mount -u */
TEST_P(UpdateErr, update)
{
struct statfs statbuf;
struct iovec *iov = NULL;
int iovlen = 0;
int flag;
int newflags = MNT_UPDATE | MNT_SYNCHRONOUS;
flag = mntflag_from_string(GetParam());
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);
})));
ASSERT_EQ(0, statfs("mountpoint", &statbuf)) << strerror(errno);
newflags = (statbuf.f_flags | MNT_UPDATE) ^ flag;
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);
/*
* Don't check nmount's return value, because vfs_domount may "fix" the
* options for us. The important thing is to check the final value of
* statbuf.f_flags below.
*/
(void)nmount(iov, iovlen, newflags);
ASSERT_EQ(0, statfs("mountpoint", &statbuf)) << strerror(errno);
EXPECT_TRUE((newflags ^ statbuf.f_flags) & flag);
}
INSTANTIATE_TEST_CASE_P(Mount, UpdateOk,
::testing::Values("MNT_RDONLY", "MNT_NOEXEC", "MNT_NOSUID", "MNT_NOATIME",
"MNT_SUIDDIR")
);
INSTANTIATE_TEST_CASE_P(Mount, UpdateErr,
::testing::Values( "MNT_USER");
);