org.apache.ignite.internal.processors.cache.persistence.file

Class IgniteNativeIoLib

java.lang.Object

org.apache.ignite.internal.processors.cache.persistence.file.IgniteNativeIoLib

public class IgniteNativeIoLib
extends Object

Native IO library based on *nix C library, enabled for Linux, kernel version >= 2.4.10.

Uses JNA library (https://github.com/java-native-access/jna) to access native calls.

Field Summary

Fields

Modifier and Type	Field and Description
static int	DEFAULT_OPEN_MODE Default access mask for newly created files.
static int	E_INVAL Invalid argument.
static int	O_CREAT File shall be created.
static int	O_DIRECT Try to minimize cache effects of the I/O to and from this file.
static int	O_EXCL If O_CREAT and O_EXCL are set, open() shall fail if the file exists.
static int	O_RDONLY Open for reading only.
static int	O_RDWR Open for reading and writing.
static int	O_SYNC Write operations on the file will complete according to the requirements of synchronized I/O file integrity completion.
static int	O_TRUNC If the file exists and is a regular file length shall be truncated to 0.
static int	O_WRONLY Open for writing only.
static int	POSIX_FADV_DONTNEED The specified data will not be accessed in the near future.
static int	S_IRGRP Flag for newly created files: group has read permission.
static int	S_IROTH Flag for newly created files: others have read permission.
static int	S_IRUSR Flag for newly created files: user has read permission.
static int	S_IWUSR Flag for newly created files: user has write permission.
static int	SEEK_CUR Seek option: change file position to offset
static int	SEEK_SET Seek option: set file offset to offset

Constructor Summary

Constructors

Constructor and Description
IgniteNativeIoLib()

Method Summary

Modifier and Type	Method and Description
static int	close(int fd) See "man 2 close".
static int	fdatasync(int fd) Synchronize a file's in-core state with storage device.
static void	free(com.sun.jna.Pointer ptr) Frees the memory space pointed to by ptr, which must have been returned by a previous call to native allocation methods.
static int	fsync(int fd) Synchronize a file's in-core state with storage device.
static int	ftruncate(int fd, long len) Causes regular file referenced by fd to be truncated to a size of precisely length bytes.
static int	getDirectIOBlockSize(String storageDir, IgniteLogger log) Determines FS and OS block size.
static int	getpagesize() The function getpagesize() returns the number of bytes in a memory page, where "page" is a fixed-length block, the unit for memory allocation and file mapping
static boolean	isJnaAvailable()
static long	lseek(int fd, long off, int whence) Repositions the file offset of the open file description associated with the file descriptor fd to the argument offset according to the directive whence
static int	open(String pathname, int flags, int mode) Open a file.
static com.sun.jna.NativeLong	pathconf(String path, int name) Return path (FS) configuration parameter value.
static int	posix_fadvise(int fd, long off, long len, int flag) Allows to announce an intention to access file data in a specific pattern in the future, thus allowing the kernel to perform appropriate optimizations.
static int	posix_memalign(com.sun.jna.ptr.PointerByReference memptr, com.sun.jna.NativeLong alignment, com.sun.jna.NativeLong size) Allocates size bytes and places the address of the allocated memory in memptr.
static com.sun.jna.NativeLong	pread(int fd, com.sun.jna.Pointer buf, com.sun.jna.NativeLong cnt, com.sun.jna.NativeLong off) Reads up to cnt bytes from file descriptor fd at offset off (from the start of the file) into the buffer starting at buf.
static com.sun.jna.NativeLong	pwrite(int fd, com.sun.jna.Pointer buf, com.sun.jna.NativeLong cnt, com.sun.jna.NativeLong off) Writes up to cnt bytes to the buffer starting at buf to the file descriptor fd at offset offset.
static com.sun.jna.NativeLong	read(int fd, com.sun.jna.Pointer buf, com.sun.jna.NativeLong cnt) Reads up to cnt bytes from file descriptor fd into the buffer starting at buf.
static String	strerror(int errnum) Function returns a string that describes the error code passed in the argument errnum.
static com.sun.jna.NativeLong	write(int fd, com.sun.jna.Pointer buf, com.sun.jna.NativeLong cnt) Writes up to cnt bytes to the buffer starting at buf to the file descriptor fd.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

O_RDONLY

public static final int O_RDONLY

Open for reading only.

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Constant Field Values

O_WRONLY

public static final int O_WRONLY

Open for writing only.

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Constant Field Values

O_RDWR

public static final int O_RDWR

Open for reading and writing.

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Constant Field Values

O_CREAT

public static final int O_CREAT

File shall be created. If the file exists, this flag has no effect.

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Constant Field Values

O_EXCL

public static final int O_EXCL

If O_CREAT and O_EXCL are set, open() shall fail if the file exists.

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Constant Field Values

O_TRUNC

public static final int O_TRUNC

If the file exists and is a regular file length shall be truncated to 0.

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Constant Field Values

O_DIRECT

public static final int O_DIRECT

Try to minimize cache effects of the I/O to and from this file.

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Constant Field Values

O_SYNC

public static final int O_SYNC

Write operations on the file will complete according to the requirements of synchronized I/O file integrity completion. By the time write(2) (or similar) returns, the output data and associated file metadata have been transferred to the underlying hardware.

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Constant Field Values

POSIX_FADV_DONTNEED

public static final int POSIX_FADV_DONTNEED

The specified data will not be accessed in the near future. See fadvise.h and "man 2 posix_fadvise".

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Constant Field Values

S_IRUSR

public static final int S_IRUSR

Flag for newly created files: user has read permission.

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Constant Field Values

S_IWUSR

public static final int S_IWUSR

Flag for newly created files: user has write permission.

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Constant Field Values

S_IRGRP

public static final int S_IRGRP

Flag for newly created files: group has read permission.

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Constant Field Values

S_IROTH

public static final int S_IROTH

Flag for newly created files: others have read permission.

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Constant Field Values

DEFAULT_OPEN_MODE

public static final int DEFAULT_OPEN_MODE

Default access mask for newly created files.

See Also:

Constant Field Values

E_INVAL

public static final int E_INVAL

Invalid argument.

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Constant Field Values

SEEK_SET

public static final int SEEK_SET

Seek option: set file offset to offset

See Also:

Constant Field Values

SEEK_CUR

public static final int SEEK_CUR

Seek option: change file position to offset

See Also:

Constant Field Values

Constructor Detail

IgniteNativeIoLib

public IgniteNativeIoLib()

Method Detail

getDirectIOBlockSize

public static int getDirectIOBlockSize(String storageDir,
                                       IgniteLogger log)

Determines FS and OS block size. Returns file system block size for use with storageDir see "man 3 posix_memalign"

Parameters:

storageDir - storage path, base path to check (FS) configuration parameters.

log - Logger.

Returns:

• FS block size to be used in Direct IO and memory alignments.
• or -1 Operating System is not applicable for enabling Direct IO.
• and -1 if failed to determine block size.
• and -1 if JNA is not available or init failed.

isJnaAvailable

public static boolean isJnaAvailable()

Returns:

Flag indicating JNA library available and initialized. Always false for non linux systems.

open

public static int open(String pathname,
                       int flags,
                       int mode)

Open a file. See "man 3 open".

Parameters:

pathname - pathname naming the file.

flags - flag/open options. Flags are constructed by a bitwise-inclusive OR of flags.

mode - create file mode creation mask.

Returns:

file descriptor.

close

public static int close(int fd)

See "man 2 close".

Parameters:

fd - The file descriptor of the file to close.

Returns:

0 on success, -1 on error.

pwrite

public static com.sun.jna.NativeLong pwrite(int fd,
                                            com.sun.jna.Pointer buf,
                                            com.sun.jna.NativeLong cnt,
                                            com.sun.jna.NativeLong off)

Writes up to cnt bytes to the buffer starting at buf to the file descriptor fd at offset offset. The file offset is not changed. See "man 2 pwrite".

Parameters:

fd - file descriptor.

buf - pointer to buffer with data.

cnt - bytes to write.

off - position in file to write data.

Returns:

the number of bytes written. Note that is not an error for a successful call to transfer fewer bytes than requested.

write

public static com.sun.jna.NativeLong write(int fd,
                                           com.sun.jna.Pointer buf,
                                           com.sun.jna.NativeLong cnt)

Writes up to cnt bytes to the buffer starting at buf to the file descriptor fd. The file offset is changed. See "man 2 write".

Parameters:

fd - file descriptor.

buf - pointer to buffer with data.

cnt - bytes to write.

Returns:

the number of bytes written. Note that is not an error for a successful call to transfer fewer bytes than requested.

pread

public static com.sun.jna.NativeLong pread(int fd,
                                           com.sun.jna.Pointer buf,
                                           com.sun.jna.NativeLong cnt,
                                           com.sun.jna.NativeLong off)

Reads up to cnt bytes from file descriptor fd at offset off (from the start of the file) into the buffer starting at buf. The file offset is not changed. See "man 2 pread".

Parameters:

fd - file descriptor.

buf - pointer to buffer to place the data.

cnt - bytes to read.

Returns:

On success, the number of bytes read is returned (zero indicates end of file), on error, -1 is returned, and errno is set appropriately.

read

public static com.sun.jna.NativeLong read(int fd,
                                          com.sun.jna.Pointer buf,
                                          com.sun.jna.NativeLong cnt)

Reads up to cnt bytes from file descriptor fd into the buffer starting at buf. The file offset is changed. See "man 2 read".

Parameters:

fd - file descriptor.

buf - pointer to buffer to place the data.

cnt - bytes to read.

Returns:

On success, the number of bytes read is returned (zero indicates end of file), on error, -1 is returned, and errno is set appropriately.

fsync

public static int fsync(int fd)

Synchronize a file's in-core state with storage device. See "man 2 fsync".

Parameters:

fd - file descriptor.

Returns:

On success return zero. On error, -1 is returned, and errno is set appropriately.

fdatasync

public static int fdatasync(int fd)

Synchronize a file's in-core state with storage device. See "man 2 fsync". Similar to fsync(int), but does not flush modified metadata unless that metadata is needed in order to allow a subsequent data retrieval to be correctly handled

Parameters:

fd - file descriptor.

Returns:

On success return zero. On error, -1 is returned, and errno is set appropriately.

posix_memalign

public static int posix_memalign(com.sun.jna.ptr.PointerByReference memptr,
                                 com.sun.jna.NativeLong alignment,
                                 com.sun.jna.NativeLong size)

Allocates size bytes and places the address of the allocated memory in memptr. The address of the allocated memory will be a multiple of alignment. See "man 3 posix_memalign".

Parameters:

memptr - out memory pointer.

alignment - memory alignment, must be a power of two and a multiple of sizeof(void *).

size - size of buffer.

Returns:

returns zero on success, or one of the error values.

free

public static void free(com.sun.jna.Pointer ptr)

Frees the memory space pointed to by ptr, which must have been returned by a previous call to native allocation methods. POSIX requires that memory obtained from posix_memalign(com.sun.jna.ptr.PointerByReference, com.sun.jna.NativeLong, com.sun.jna.NativeLong) can be freed using free. See "man 3 free".

Parameters:

ptr - pointer to free.

strerror

public static String strerror(int errnum)

Function returns a string that describes the error code passed in the argument errnum. See "man 3 strerror".

Parameters:

errnum - error code.

Returns:

displayable error information.

pathconf

public static com.sun.jna.NativeLong pathconf(String path,
                                              int name)

Return path (FS) configuration parameter value.
Helps to determine alignment restrictions, for example, on buffers used for direct block device I/O.
POSIX specifies the pathconf(path,_PC_REC_XFER_ALIGN) call that tells what alignment is needed.

Parameters:

path - base path to check settings.

name - variable name to query.

getpagesize

public static int getpagesize()

The function getpagesize() returns the number of bytes in a memory page, where "page" is a fixed-length block, the unit for memory allocation and file mapping

posix_fadvise

public static int posix_fadvise(int fd,
                                long off,
                                long len,
                                int flag)

Allows to announce an intention to access file data in a specific pattern in the future, thus allowing the kernel to perform appropriate optimizations. The advice applies to a (not necessarily existent) region starting at off and extending for len bytes (or until the end of the file if len is 0) within the file referred to by fd. See "man 2 posix_fadvise".

Parameters:

fd - file descriptor.

off - region start.

len - region end.

flag - advice (option) to apply.

Returns:

On success, zero is returned. On error, an error number is returned.

ftruncate

public static int ftruncate(int fd,
                            long len)

Causes regular file referenced by fd to be truncated to a size of precisely length bytes. If the file previously was larger than this size, the extra data is lost. If the file previously was shorter, it is extended, and the extended part reads as null bytes ('\0'). The file offset is not changed.

Parameters:

fd - file descriptor.

len - required length.

Returns:

On success, zero is returned. On error, -1 is returned, and errno is set appropriately.

lseek

public static long lseek(int fd,
                         long off,
                         int whence)

Repositions the file offset of the open file description associated with the file descriptor fd to the argument offset according to the directive whence

Parameters:

fd - file descriptor.

off - required position offset.

whence - position base.

Returns:

On error, the value -1 is returned and errno is set to indicate the error.