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Add fh support for revise attr and fstat(2) test 

According to Linux 4.4's FUSE behavior, the flags and fh attributes in
FUSE_GETATTR are only used in read, write, and lseek. fstat(2) doesn't
use them either. Add tests to ensure the requests sent from FUSE module
are consistent with Linux's.

Updates #3655
This commit is contained in:
Craig Chi 2020-09-09 09:16:09 -07:00 committed by Andrei Vagin
parent 1146ab6bac
commit 4181e8c974
7 changed files with 133 additions and 28 deletions
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5
pkg/abi/linux/fuse.go
View File

@ -227,6 +227,11 @@ type FUSEInitOut struct {
_ [8]uint32
}
// FUSE_GETATTR_FH is currently the only flag of FUSEGetAttrIn.GetAttrFlags.
// If it is set, the file handle (FUSEGetAttrIn.Fh) is used to indicate the
// object instead of the node id attribute in the request header.
const FUSE_GETATTR_FH = (1 << 0)
// FUSEGetAttrIn is the request sent by the kernel to the daemon,
// to get the attribute of a inode.
//

21
pkg/sentry/fsimpl/fuse/fusefs.go
View File

@ -609,9 +609,9 @@ func statFromFUSEAttr(attr linux.FUSEAttr, mask, devMinor uint32) linux.Statx {
}
// getAttr gets the attribute of this inode by issuing a FUSE_GETATTR request
// or read from local cache.
// It updates the corresponding attributes if necessary.
func (i *inode) getAttr(ctx context.Context, fs *vfs.Filesystem, opts vfs.StatOptions) (linux.FUSEAttr, error) {
// or read from local cache. It updates the corresponding attributes if
// necessary.
func (i *inode) getAttr(ctx context.Context, fs *vfs.Filesystem, opts vfs.StatOptions, flags uint32, fh uint64) (linux.FUSEAttr, error) {
attributeVersion := atomic.LoadUint64(&i.fs.conn.attributeVersion)
// TODO(gvisor.dev/issue/3679): send the request only if
@ -631,11 +631,10 @@ func (i *inode) getAttr(ctx context.Context, fs *vfs.Filesystem, opts vfs.StatOp
creds := auth.CredentialsFromContext(ctx)
var in linux.FUSEGetAttrIn
// We don't set any attribute in the request, because in VFS2 fstat(2) will
// finally be translated into vfs.FilesystemImpl.StatAt() (see
// pkg/sentry/syscalls/linux/vfs2/stat.go), resulting in the same flow
// as stat(2). Thus GetAttrFlags and Fh variable will never be used in VFS2.
in := linux.FUSEGetAttrIn{
GetAttrFlags: flags,
Fh: fh,
}
req, err := i.fs.conn.NewRequest(creds, uint32(task.ThreadID()), i.NodeID, linux.FUSE_GETATTR, &in)
if err != nil {
return linux.FUSEAttr{}, err
@ -676,17 +675,17 @@ func (i *inode) getAttr(ctx context.Context, fs *vfs.Filesystem, opts vfs.StatOp
// reviseAttr attempts to update the attributes for internal purposes
// by calling getAttr with a pre-specified mask.
// Used by read, write, lseek.
func (i *inode) reviseAttr(ctx context.Context) error {
func (i *inode) reviseAttr(ctx context.Context, flags uint32, fh uint64) error {
// Never need atime for internal purposes.
_, err := i.getAttr(ctx, i.fs.VFSFilesystem(), vfs.StatOptions{
Mask: linux.STATX_BASIC_STATS &^ linux.STATX_ATIME,
})
}, flags, fh)
return err
}
// Stat implements kernfs.Inode.Stat.
func (i *inode) Stat(ctx context.Context, fs *vfs.Filesystem, opts vfs.StatOptions) (linux.Statx, error) {
attr, err := i.getAttr(ctx, fs, opts)
attr, err := i.getAttr(ctx, fs, opts, 0, 0)
if err != nil {
return linux.Statx{}, err
}

2
pkg/sentry/fsimpl/fuse/regular_file.go
View File

@ -65,7 +65,7 @@ func (fd *regularFileFD) PRead(ctx context.Context, dst usermem.IOSequence, offs
// Reading beyond EOF, update file size if outdated.
if uint64(offset+size) > atomic.LoadUint64(&inode.size) {
if err := inode.reviseAttr(ctx); err != nil {
if err := inode.reviseAttr(ctx, linux.FUSE_GETATTR_FH, fd.Fh); err != nil {
return 0, err
}
// If the offset after update is still too large, return error.

4
test/fuse/linux/BUILD
View File

@ -11,7 +11,9 @@ cc_binary(
srcs = ["stat_test.cc"],
deps = [
gtest,
":fuse_base",
":fuse_fd_util",
"//test/util:cleanup",
"//test/util:fs_util",
"//test/util:fuse_util",
"//test/util:test_main",
"//test/util:test_util",

112
test/fuse/linux/stat_test.cc
View File

@ -18,12 +18,15 @@
#include <sys/stat.h>
#include <sys/statfs.h>
#include <sys/types.h>
#include <sys/uio.h>
#include <unistd.h>
#include <vector>
#include "gtest/gtest.h"
#include "test/fuse/linux/fuse_base.h"
#include "test/fuse/linux/fuse_fd_util.h"
#include "test/util/cleanup.h"
#include "test/util/fs_util.h"
#include "test/util/fuse_util.h"
#include "test/util/test_util.h"
@ -32,19 +35,30 @@ namespace testing {
namespace {
class StatTest : public FuseTest {
class StatTest : public FuseFdTest {
public:
void SetUp() override {
FuseFdTest::SetUp();
test_file_path_ = JoinPath(mount_point_.path(), test_file_);
}
protected:
bool StatsAreEqual(struct stat expected, struct stat actual) {
// device number will be dynamically allocated by kernel, we cannot know
// in advance
// Device number will be dynamically allocated by kernel, we cannot know in
// advance.
actual.st_dev = expected.st_dev;
return memcmp(&expected, &actual, sizeof(struct stat)) == 0;
}
const std::string test_file_ = "testfile";
const mode_t expected_mode = S_IFREG | S_IRUSR | S_IWUSR;
const uint64_t fh = 23;
std::string test_file_path_;
};
TEST_F(StatTest, StatNormal) {
// Set up fixture.
mode_t expected_mode = S_IRWXU | S_IRGRP | S_IXGRP | S_IROTH | S_IXOTH;
struct fuse_attr attr = DefaultFuseAttr(expected_mode, 1);
struct fuse_out_header out_header = {
.len = sizeof(struct fuse_out_header) + sizeof(struct fuse_attr_out),
@ -55,7 +69,7 @@ TEST_F(StatTest, StatNormal) {
auto iov_out = FuseGenerateIovecs(out_header, out_payload);
SetServerResponse(FUSE_GETATTR, iov_out);
// Do integration test.
// Make syscall.
struct stat stat_buf;
EXPECT_THAT(stat(mount_point_.path().c_str(), &stat_buf), SyscallSucceeds());
@ -99,7 +113,7 @@ TEST_F(StatTest, StatNotFound) {
auto iov_out = FuseGenerateIovecs(out_header);
SetServerResponse(FUSE_GETATTR, iov_out);
// Do integration test.
// Make syscall.
struct stat stat_buf;
EXPECT_THAT(stat(mount_point_.path().c_str(), &stat_buf),
SyscallFailsWithErrno(ENOENT));
@ -115,6 +129,90 @@ TEST_F(StatTest, StatNotFound) {
EXPECT_EQ(in_payload.fh, 0);
}
TEST_F(StatTest, FstatNormal) {
// Set up fixture.
SetServerInodeLookup(test_file_);
auto fd = ASSERT_NO_ERRNO_AND_VALUE(OpenPath(test_file_path_, O_RDONLY, fh));
auto close_fd = CloseFD(fd);
struct fuse_attr attr = DefaultFuseAttr(expected_mode, 2);
struct fuse_out_header out_header = {
.len = sizeof(struct fuse_out_header) + sizeof(struct fuse_attr_out),
};
struct fuse_attr_out out_payload = {
.attr = attr,
};
auto iov_out = FuseGenerateIovecs(out_header, out_payload);
SetServerResponse(FUSE_GETATTR, iov_out);
// Make syscall.
struct stat stat_buf;
EXPECT_THAT(fstat(fd.get(), &stat_buf), SyscallSucceeds());
// Check filesystem operation result.
struct stat expected_stat = {
.st_ino = attr.ino,
.st_nlink = attr.nlink,
.st_mode = expected_mode,
.st_uid = attr.uid,
.st_gid = attr.gid,
.st_rdev = attr.rdev,
.st_size = static_cast<off_t>(attr.size),
.st_blksize = attr.blksize,
.st_blocks = static_cast<blkcnt_t>(attr.blocks),
.st_atim = (struct timespec){.tv_sec = static_cast<int>(attr.atime),
.tv_nsec = attr.atimensec},
.st_mtim = (struct timespec){.tv_sec = static_cast<int>(attr.mtime),
.tv_nsec = attr.mtimensec},
.st_ctim = (struct timespec){.tv_sec = static_cast<int>(attr.ctime),
.tv_nsec = attr.ctimensec},
};
EXPECT_TRUE(StatsAreEqual(stat_buf, expected_stat));
// Check FUSE request.
struct fuse_in_header in_header;
struct fuse_getattr_in in_payload;
auto iov_in = FuseGenerateIovecs(in_header, in_payload);
GetServerActualRequest(iov_in);
EXPECT_EQ(in_header.opcode, FUSE_GETATTR);
EXPECT_EQ(in_payload.getattr_flags, 0);
EXPECT_EQ(in_payload.fh, 0);
}
TEST_F(StatTest, StatByFileHandle) {
// Set up fixture.
SetServerInodeLookup(test_file_, expected_mode, 0);
auto fd = ASSERT_NO_ERRNO_AND_VALUE(OpenPath(test_file_path_, O_RDONLY, fh));
auto close_fd = CloseFD(fd);
struct fuse_attr attr = DefaultFuseAttr(expected_mode, 2, 0);
struct fuse_out_header out_header = {
.len = sizeof(struct fuse_out_header) + sizeof(struct fuse_attr_out),
};
struct fuse_attr_out out_payload = {
.attr = attr,
};
auto iov_out = FuseGenerateIovecs(out_header, out_payload);
SetServerResponse(FUSE_GETATTR, iov_out);
// Make syscall.
std::vector<char> buf(1);
// Since this is an empty file, it won't issue FUSE_READ. But a FUSE_GETATTR
// will be issued before read completes.
EXPECT_THAT(read(fd.get(), buf.data(), buf.size()), SyscallSucceeds());
// Check FUSE request.
struct fuse_in_header in_header;
struct fuse_getattr_in in_payload;
auto iov_in = FuseGenerateIovecs(in_header, in_payload);
GetServerActualRequest(iov_in);
EXPECT_EQ(in_header.opcode, FUSE_GETATTR);
EXPECT_EQ(in_payload.getattr_flags, FUSE_GETATTR_FH);
EXPECT_EQ(in_payload.fh, fh);
}
} // namespace
} // namespace testing

12
test/util/fuse_util.cc
View File

@ -22,13 +22,13 @@
namespace gvisor {
namespace testing {
// Create a default FuseAttr struct with specified mode and inode.
fuse_attr DefaultFuseAttr(mode_t mode, uint64_t inode) {
// Create a default FuseAttr struct with specified mode, inode, and size.
fuse_attr DefaultFuseAttr(mode_t mode, uint64_t inode, uint64_t size) {
const int time_sec = 1595436289;
const int time_nsec = 134150844;
return (struct fuse_attr){
.ino = inode,
.size = 512,
.size = size,
.blocks = 4,
.atime = time_sec,
.mtime = time_sec,
@ -45,8 +45,8 @@ fuse_attr DefaultFuseAttr(mode_t mode, uint64_t inode) {
};
}
// Create response body with specified mode and nodeID.
fuse_entry_out DefaultEntryOut(mode_t mode, uint64_t node_id) {
// Create response body with specified mode, nodeID, and size.
fuse_entry_out DefaultEntryOut(mode_t mode, uint64_t node_id, uint64_t size) {
struct fuse_entry_out default_entry_out = {
.nodeid = node_id,
.generation = 0,
@ -54,7 +54,7 @@ fuse_entry_out DefaultEntryOut(mode_t mode, uint64_t node_id) {
.attr_valid = 0,
.entry_valid_nsec = 0,
.attr_valid_nsec = 0,
.attr = DefaultFuseAttr(mode, node_id),
.attr = DefaultFuseAttr(mode, node_id, size),
};
return default_entry_out;
};

5
test/util/fuse_util.h
View File

@ -64,10 +64,11 @@ std::vector<struct iovec> FuseGenerateIovecs(T &first, Types &...args) {
}
// Create a fuse_attr filled with the specified mode and inode.
fuse_attr DefaultFuseAttr(mode_t mode, uint64_t inode);
fuse_attr DefaultFuseAttr(mode_t mode, uint64_t inode, uint64_t size = 512);
// Return a fuse_entry_out FUSE server response body.
fuse_entry_out DefaultEntryOut(mode_t mode, uint64_t nodeId);
fuse_entry_out DefaultEntryOut(mode_t mode, uint64_t node_id,
uint64_t size = 512);
} // namespace testing
} // namespace gvisor