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8293121: (fs) Refactor UnixFileSystem copying into generic Unix, Linu…
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…x, and BSD implementations

Reviewed-by: alanb
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Brian Burkhalter committed Sep 1, 2022
1 parent 032be16 commit 0a4d0ce
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Showing 11 changed files with 1,051 additions and 854 deletions.
62 changes: 57 additions & 5 deletions src/java.base/linux/classes/sun/nio/fs/LinuxFileSystem.java
Original file line number Diff line number Diff line change
@@ -1,5 +1,5 @@
/*
* Copyright (c) 2008, 2019, Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 2008, 2022, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
Expand All @@ -25,10 +25,16 @@

package sun.nio.fs;

import java.nio.file.*;
import java.nio.file.FileStore;
import java.nio.file.WatchService;
import java.io.IOException;
import java.util.*;
import java.util.ArrayList;
import java.util.Collections;
import java.util.HashSet;
import java.util.List;
import java.util.Set;
import static sun.nio.fs.LinuxNativeDispatcher.*;
import static sun.nio.fs.UnixConstants.*;

/**
* Linux implementation of FileSystem
Expand Down Expand Up @@ -121,10 +127,56 @@ List<UnixMountEntry> getMountEntries() {
return getMountEntries("/etc/mtab");
}



@Override
FileStore getFileStore(UnixMountEntry entry) throws IOException {
return new LinuxFileStore(this, entry);
}

// --- file copying ---

@Override
void bufferedCopy(int dst, int src, long address,
int size, long addressToPollForCancel)
throws UnixException
{
int advice = POSIX_FADV_SEQUENTIAL | // sequential data access
POSIX_FADV_NOREUSE | // will access only once
POSIX_FADV_WILLNEED; // will access in near future
posix_fadvise(src, 0, 0, advice);

super.bufferedCopy(dst, src, address, size, addressToPollForCancel);
}

@Override
int directCopy(int dst, int src, long addressToPollForCancel)
throws UnixException
{
int advice = POSIX_FADV_SEQUENTIAL | // sequential data access
POSIX_FADV_NOREUSE | // will access only once
POSIX_FADV_WILLNEED; // will access in near future
posix_fadvise(src, 0, 0, advice);

return directCopy0(dst, src, addressToPollForCancel);
}

// -- native methods --

/**
* Copies data between file descriptors {@code src} and {@code dst} using
* a platform-specific function or system call possibly having kernel
* support.
*
* @param dst destination file descriptor
* @param src source file descriptor
* @param addressToPollForCancel address to check for cancellation
* (a non-zero value written to this address indicates cancel)
*
* @return 0 on success, UNAVAILABLE if the platform function would block,
* UNSUPPORTED_CASE if the call does not work with the given
* parameters, or UNSUPPORTED if direct copying is not supported
* on this platform
*/
private static native int directCopy0(int dst, int src,
long addressToPollForCancel)
throws UnixException;
}
Original file line number Diff line number Diff line change
Expand Up @@ -62,6 +62,12 @@ static native int getmntent0(long fp, UnixMountEntry entry, long buffer, int buf
*/
static native void endmntent(long stream) throws UnixException;

/**
* int posix_fadvise(int fd, off_t offset, off_t len, int advice);
*/
static native int posix_fadvise(int fd, long offset, long len, int advice)
throws UnixException;

// initialize
private static native void init();

Expand Down
94 changes: 94 additions & 0 deletions src/java.base/linux/native/libnio/fs/LinuxFileSystem.c
Original file line number Diff line number Diff line change
@@ -0,0 +1,94 @@
/*
* Copyright (c) 2022, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation. Oracle designates this
* particular file as subject to the "Classpath" exception as provided
* by Oracle in the LICENSE file that accompanied this code.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
* or visit www.oracle.com if you need additional information or have any
* questions.
*/

#include "jni.h"
#include "jni_util.h"
#include "jlong.h"

#include "nio.h"

#include <stdlib.h>
#include <unistd.h>
#include <errno.h>

#include <sys/sendfile.h>
#include <fcntl.h>

#include "sun_nio_fs_LinuxFileSystem.h"

#define RESTARTABLE(_cmd, _result) do { \
do { \
_result = _cmd; \
} while((_result == -1) && (errno == EINTR)); \
} while(0)

static void throwUnixException(JNIEnv* env, int errnum) {
jobject x = JNU_NewObjectByName(env, "sun/nio/fs/UnixException",
"(I)V", errnum);
if (x != NULL) {
(*env)->Throw(env, x);
}
}

// Copy all bytes from src to dst, within the kernel if possible,
// and return zero, otherwise return the appropriate status code.
//
// Return value
// 0 on success
// IOS_UNAVAILABLE if the platform function would block
// IOS_UNSUPPORTED_CASE if the call does not work with the given parameters
// IOS_UNSUPPORTED if direct copying is not supported on this platform
// IOS_THROWN if a Java exception is thrown
//
JNIEXPORT jint JNICALL
Java_sun_nio_fs_LinuxFileSystem_directCopy0
(JNIEnv* env, jclass this, jint dst, jint src, jlong cancelAddress)
{
volatile jint* cancel = (jint*)jlong_to_ptr(cancelAddress);

// Transfer within the kernel
const size_t count = cancel != NULL ?
1048576 : // 1 MB to give cancellation a chance
0x7ffff000; // maximum number of bytes that sendfile() can transfer
ssize_t bytes_sent;

do {
RESTARTABLE(sendfile64(dst, src, NULL, count), bytes_sent);
if (bytes_sent < 0) {
if (errno == EAGAIN)
return IOS_UNAVAILABLE;
if (errno == EINVAL || errno == ENOSYS)
return IOS_UNSUPPORTED_CASE;
throwUnixException(env, errno);
return IOS_THROWN;
}
if (cancel != NULL && *cancel != 0) {
throwUnixException(env, ECANCELED);
return IOS_THROWN;
}
} while (bytes_sent > 0);

return 0;
}
12 changes: 10 additions & 2 deletions src/java.base/linux/native/libnio/fs/LinuxNativeDispatcher.c
Original file line number Diff line number Diff line change
@@ -1,5 +1,5 @@
/*
* Copyright (c) 2008, 2019, Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 2008, 2022, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
Expand Down Expand Up @@ -33,6 +33,7 @@
#include <dlfcn.h>
#include <errno.h>
#include <mntent.h>
#include <fcntl.h>

#include "sun_nio_fs_LinuxNativeDispatcher.h"

Expand Down Expand Up @@ -139,6 +140,13 @@ JNIEXPORT void JNICALL
Java_sun_nio_fs_LinuxNativeDispatcher_endmntent(JNIEnv* env, jclass this, jlong stream)
{
FILE* fp = jlong_to_ptr(stream);
/* FIXME - man page doesn't explain how errors are returned */
// The endmntent() function always returns 1.
endmntent(fp);
}

JNIEXPORT jint JNICALL
Java_sun_nio_fs_LinuxNativeDispatcher_posix_1fadvise(JNIEnv* env, jclass this,
jint fd, jlong offset, jlong len, jint advice)
{
return posix_fadvise64((int)fd, (off64_t)offset, (off64_t)len, (int)advice);
}
25 changes: 22 additions & 3 deletions src/java.base/macosx/classes/sun/nio/fs/BsdFileSystem.java
Original file line number Diff line number Diff line change
@@ -1,5 +1,5 @@
/*
* Copyright (c) 2008, 2012, Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 2008, 2022, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
Expand All @@ -25,10 +25,14 @@

package sun.nio.fs;

import java.nio.file.*;
import java.io.IOException;
import java.util.*;
import java.nio.file.FileStore;
import java.nio.file.WatchService;
import java.security.AccessController;
import java.util.ArrayList;
import java.util.Collections;
import java.util.HashSet;
import java.util.Set;
import sun.security.action.GetPropertyAction;

/**
Expand Down Expand Up @@ -104,4 +108,19 @@ Iterable<UnixMountEntry> getMountEntries() {
FileStore getFileStore(UnixMountEntry entry) throws IOException {
return new BsdFileStore(this, entry);
}

// --- file copying ---

@Override
int directCopy(int dst, int src, long addressToPollForCancel)
throws UnixException
{
return directCopy0(dst, src, addressToPollForCancel);
}

// -- native methods --

private static native int directCopy0(int dst, int src,
long addressToPollForCancel)
throws UnixException;
}
Original file line number Diff line number Diff line change
@@ -1,5 +1,5 @@
/*
* Copyright (c) 2008, 2022, Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 2022, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
Expand Down Expand Up @@ -33,13 +33,8 @@
#include <unistd.h>
#include <errno.h>

#if defined(__linux__)
#include <sys/sendfile.h>
#include <fcntl.h>
#elif defined(_ALLBSD_SOURCE)
#include <copyfile.h>
#endif
#include "sun_nio_fs_UnixCopyFile.h"
#include "sun_nio_fs_BsdFileSystem.h"

#define RESTARTABLE(_cmd, _result) do { \
do { \
Expand All @@ -55,7 +50,6 @@ static void throwUnixException(JNIEnv* env, int errnum) {
}
}

#if defined(_ALLBSD_SOURCE)
int fcopyfile_callback(int what, int stage, copyfile_state_t state,
const char* src, const char* dst, void* cancel)
{
Expand All @@ -70,54 +64,6 @@ int fcopyfile_callback(int what, int stage, copyfile_state_t state,
}
return COPYFILE_CONTINUE;
}
#endif

// Copy via an intermediate temporary direct buffer
JNIEXPORT void JNICALL
Java_sun_nio_fs_UnixCopyFile_bufferedCopy0
(JNIEnv* env, jclass this, jint dst, jint src, jlong address,
jint transferSize, jlong cancelAddress)
{
volatile jint* cancel = (jint*)jlong_to_ptr(cancelAddress);

char* buf = (char*)jlong_to_ptr(address);

#if defined(__linux__)
int advice = POSIX_FADV_SEQUENTIAL | // sequential data access
POSIX_FADV_NOREUSE | // will access only once
POSIX_FADV_WILLNEED; // will access in near future

// ignore the return value hence any failure
posix_fadvise(src, 0, 0, advice);
#endif

for (;;) {
ssize_t n, pos, len;
RESTARTABLE(read((int)src, buf, transferSize), n);
if (n <= 0) {
if (n < 0)
throwUnixException(env, errno);
return;
}
if (cancel != NULL && *cancel != 0) {
throwUnixException(env, ECANCELED);
return;
}
pos = 0;
len = n;
do {
char* bufp = buf;
bufp += pos;
RESTARTABLE(write((int)dst, bufp, len), n);
if (n == -1) {
throwUnixException(env, errno);
return;
}
pos += n;
len -= n;
} while (len > 0);
}
}

// Copy all bytes from src to dst, within the kernel if possible (Linux),
// and return zero, otherwise return the appropriate status code.
Expand All @@ -130,35 +76,11 @@ Java_sun_nio_fs_UnixCopyFile_bufferedCopy0
// IOS_THROWN if a Java exception is thrown
//
JNIEXPORT jint JNICALL
Java_sun_nio_fs_UnixCopyFile_directCopy0
Java_sun_nio_fs_BsdFileSystem_directCopy0
(JNIEnv* env, jclass this, jint dst, jint src, jlong cancelAddress)
{
volatile jint* cancel = (jint*)jlong_to_ptr(cancelAddress);

#if defined(__linux__)
// Transfer within the kernel
const size_t count = cancel != NULL ?
1048576 : // 1 MB to give cancellation a chance
0x7ffff000; // maximum number of bytes that sendfile() can transfer
ssize_t bytes_sent;
do {
RESTARTABLE(sendfile64(dst, src, NULL, count), bytes_sent);
if (bytes_sent < 0) {
if (errno == EAGAIN)
return IOS_UNAVAILABLE;
if (errno == EINVAL || errno == ENOSYS)
return IOS_UNSUPPORTED_CASE;
throwUnixException(env, errno);
return IOS_THROWN;
}
if (cancel != NULL && *cancel != 0) {
throwUnixException(env, ECANCELED);
return IOS_THROWN;
}
} while (bytes_sent > 0);

return 0;
#elif defined(_ALLBSD_SOURCE)
copyfile_state_t state;
if (cancel != NULL) {
state = copyfile_state_alloc();
Expand All @@ -178,7 +100,4 @@ Java_sun_nio_fs_UnixCopyFile_directCopy0
copyfile_state_free(state);

return 0;
#else
return IOS_UNSUPPORTED;
#endif
}

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