alluxio.fuse

Class AlluxioJnrFuseFileSystem

java.lang.Object

ru.serce.jnrfuse.AbstractFuseFS

ru.serce.jnrfuse.FuseStubFS

alluxio.fuse.AlluxioJnrFuseFileSystem

All Implemented Interfaces:

FuseUmountable, ru.serce.jnrfuse.FuseFS, ru.serce.jnrfuse.Mountable

@ThreadSafe
public final class AlluxioJnrFuseFileSystem
extends ru.serce.jnrfuse.FuseStubFS
implements FuseUmountable

Main FUSE implementation class. Implements the FUSE callbacks defined by jnr-fuse.

Field Summary

Fields

Modifier and Type	Field and Description
static long	ID_NOT_SET_VALUE 4294967295 is unsigned long -1, -1 means that uid or gid is not set.
static long	ID_NOT_SET_VALUE_UNSIGNED
static int	MAX_NAME_LENGTH Most FileSystems on linux limit the length of file name beyond 255 characters.
static int	UNKNOWN_INODES df command will treat -1 as an unknown value.

Fields inherited from class ru.serce.jnrfuse.AbstractFuseFS

fuseOperations, libFuse, mounted, mountPoint

Constructor Summary

Constructors

Constructor and Description
AlluxioJnrFuseFileSystem(FileSystem fs, AlluxioConfiguration conf, FuseOptions fuseOptions) Creates a new instance of AlluxioJnrFuseFileSystem.

Method Summary

Modifier and Type	Method and Description
int	chmod(String path, long mode) Changes the mode of an Alluxio file.
int	chown(String path, long uid, long gid) Changes the user and group ownership of an Alluxio file.
int	create(String path, long mode, ru.serce.jnrfuse.struct.FuseFileInfo fi) Creates and opens a new file.
int	flush(String path, ru.serce.jnrfuse.struct.FuseFileInfo fi) Flushes cached data on Alluxio.
int	getattr(String path, ru.serce.jnrfuse.struct.FileStat stat) Retrieves file attributes.
String	getFSName()
int	mkdir(String path, long mode) Creates a new dir.
void	mount(Path mountPoint, boolean blocking, boolean debug, String[] fuseOpts)
int	open(String path, ru.serce.jnrfuse.struct.FuseFileInfo fi) Opens an existing file for reading.
int	read(String path, jnr.ffi.Pointer buf, long size, long offset, ru.serce.jnrfuse.struct.FuseFileInfo fi) Reads data from an open file.
int	readdir(String path, jnr.ffi.Pointer buff, ru.serce.jnrfuse.FuseFillDir filter, long offset, ru.serce.jnrfuse.struct.FuseFileInfo fi) Reads the contents of a directory.
int	release(String path, ru.serce.jnrfuse.struct.FuseFileInfo fi) Releases the resources associated to an open file.
int	rename(String oldPath, String newPath) Renames a path.
int	rmdir(String path) Deletes an empty directory.
int	statfs(String path, ru.serce.jnrfuse.struct.Statvfs stbuf) Gets the filesystem statistics.
int	truncate(String path, long size) Changes the size of a file.
void	umount(boolean force) Unmounts the Fuse application.
int	unlink(String path) Deletes a file from the FS.
int	utimens(String path, ru.serce.jnrfuse.struct.Timespec[] timespec) Alluxio does not have access time, and the file is created only once.
int	write(String path, jnr.ffi.Pointer buf, long size, long offset, ru.serce.jnrfuse.struct.FuseFileInfo fi) Writes a buffer to an open Alluxio file.

Methods inherited from class ru.serce.jnrfuse.FuseStubFS

access, bmap, destroy, fallocate, fgetattr, flock, fsync, fsyncdir, ftruncate, getxattr, init, ioctl, link, listxattr, lock, mknod, opendir, poll, read_buf, readlink, releasedir, removexattr, setxattr, symlink, write_buf

Methods inherited from class ru.serce.jnrfuse.AbstractFuseFS

getContext, umount

Methods inherited from class java.lang.Object

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

Methods inherited from interface ru.serce.jnrfuse.Mountable

mount, mount, mount

Field Detail

UNKNOWN_INODES

public static final int UNKNOWN_INODES

df command will treat -1 as an unknown value.

See Also:

Constant Field Values

MAX_NAME_LENGTH

public static final int MAX_NAME_LENGTH

Most FileSystems on linux limit the length of file name beyond 255 characters.

See Also:

Constant Field Values

ID_NOT_SET_VALUE

public static final long ID_NOT_SET_VALUE

4294967295 is unsigned long -1, -1 means that uid or gid is not set. 4294967295 or -1 occurs when chown without user name or group name. Please view https://github.com/SerCeMan/jnr-fuse/issues/67 for more details.

See Also:

Constant Field Values

ID_NOT_SET_VALUE_UNSIGNED

public static final long ID_NOT_SET_VALUE_UNSIGNED

See Also:

Constant Field Values

Constructor Detail

AlluxioJnrFuseFileSystem

public AlluxioJnrFuseFileSystem(FileSystem fs,
                                AlluxioConfiguration conf,
                                FuseOptions fuseOptions)

Creates a new instance of AlluxioJnrFuseFileSystem.

Parameters:

fs - Alluxio file system

conf - the Alluxio configuration containing Fuse options

fuseOptions - the FUSE options

Method Detail

chmod

public int chmod(String path,
                 long mode)

Changes the mode of an Alluxio file.

Specified by:

chmod in interface ru.serce.jnrfuse.FuseFS

Overrides:

chmod in class ru.serce.jnrfuse.FuseStubFS

Parameters:

path - the path of the file

mode - the mode to change to

Returns:

0 on success, a negative value on error

chown

public int chown(String path,
                 long uid,
                 long gid)

Changes the user and group ownership of an Alluxio file. This operation only works when the user group translation is enabled in Alluxio-FUSE.

Specified by:

chown in interface ru.serce.jnrfuse.FuseFS

Overrides:

chown in class ru.serce.jnrfuse.FuseStubFS

Parameters:

path - the path of the file

uid - the uid to change to

gid - the gid to change to

Returns:

0 on success, a negative value on error

create

public int create(String path,
                  long mode,
                  ru.serce.jnrfuse.struct.FuseFileInfo fi)

Creates and opens a new file.

Specified by:

create in interface ru.serce.jnrfuse.FuseFS

Overrides:

create in class ru.serce.jnrfuse.FuseStubFS

Parameters:

path - The FS path of the file to open

mode - mode flags

fi - FileInfo data struct kept by FUSE

Returns:

0 on success. A negative value on error

flush

public int flush(String path,
                 ru.serce.jnrfuse.struct.FuseFileInfo fi)

Flushes cached data on Alluxio. Called on explicit sync() operation or at close().

Specified by:

flush in interface ru.serce.jnrfuse.FuseFS

Overrides:

flush in class ru.serce.jnrfuse.FuseStubFS

Parameters:

path - The path on the FS of the file to close

fi - FileInfo data struct kept by FUSE

Returns:

0 on success, a negative value on error

getattr

public int getattr(String path,
                   ru.serce.jnrfuse.struct.FileStat stat)

Retrieves file attributes.

Specified by:

getattr in interface ru.serce.jnrfuse.FuseFS

Overrides:

getattr in class ru.serce.jnrfuse.FuseStubFS

Parameters:

path - The path on the FS of the file

stat - FUSE data structure to fill with file attrs

Returns:

0 on success, negative value on error

getFSName

public String getFSName()

Overrides:

getFSName in class ru.serce.jnrfuse.AbstractFuseFS

Returns:

Name of the file system

mkdir

public int mkdir(String path,
                 long mode)

Creates a new dir.

Specified by:

mkdir in interface ru.serce.jnrfuse.FuseFS

Overrides:

mkdir in class ru.serce.jnrfuse.FuseStubFS

Parameters:

path - the path on the FS of the new dir

mode - Dir creation flags (IGNORED)

Returns:

0 on success, a negative value on error

open

public int open(String path,
                ru.serce.jnrfuse.struct.FuseFileInfo fi)

Opens an existing file for reading. Note that the opening an existing file would fail, because of Alluxio's write-once semantics.

Specified by:

open in interface ru.serce.jnrfuse.FuseFS

Overrides:

open in class ru.serce.jnrfuse.FuseStubFS

Parameters:

path - the FS path of the file to open

fi - FileInfo data structure kept by FUSE

Returns:

0 on success, a negative value on error

read

public int read(String path,
                jnr.ffi.Pointer buf,
                long size,
                long offset,
                ru.serce.jnrfuse.struct.FuseFileInfo fi)

Reads data from an open file.

Specified by:

read in interface ru.serce.jnrfuse.FuseFS

Overrides:

read in class ru.serce.jnrfuse.FuseStubFS

Parameters:

path - the FS path of the file to read

buf - FUSE buffer to fill with data read

size - how many bytes to read. The maximum value that is accepted on this method is Integer.MAX_VALUE (note that current FUSE implementation will call this method with a size of at most 128K).

offset - offset of the read operation

fi - FileInfo data structure kept by FUSE

Returns:

the number of bytes read or 0 on EOF. A negative value on error

readdir

public int readdir(String path,
                   jnr.ffi.Pointer buff,
                   ru.serce.jnrfuse.FuseFillDir filter,
                   long offset,
                   ru.serce.jnrfuse.struct.FuseFileInfo fi)

Reads the contents of a directory.

Specified by:

readdir in interface ru.serce.jnrfuse.FuseFS

Overrides:

readdir in class ru.serce.jnrfuse.FuseStubFS

Parameters:

path - The FS path of the directory

buff - The FUSE buffer to fill

filter - FUSE filter

offset - Ignored in alluxio-fuse

fi - FileInfo data structure kept by FUSE

Returns:

0 on success, a negative value on error

release

public int release(String path,
                   ru.serce.jnrfuse.struct.FuseFileInfo fi)

Releases the resources associated to an open file. Release() is async. Guaranteed to be called once for each open() or create().

Specified by:

release in interface ru.serce.jnrfuse.FuseFS

Overrides:

release in class ru.serce.jnrfuse.FuseStubFS

Parameters:

path - the FS path of the file to release

fi - FileInfo data structure kept by FUSE

Returns:

0. The return value is ignored by FUSE (any error should be reported on flush instead)

rename

public int rename(String oldPath,
                  String newPath)

Renames a path.

Specified by:

rename in interface ru.serce.jnrfuse.FuseFS

Overrides:

rename in class ru.serce.jnrfuse.FuseStubFS

Parameters:

oldPath - the source path in the FS

newPath - the destination path in the FS

Returns:

0 on success, a negative value on error

rmdir

public int rmdir(String path)

Deletes an empty directory.

Specified by:

rmdir in interface ru.serce.jnrfuse.FuseFS

Overrides:

rmdir in class ru.serce.jnrfuse.FuseStubFS

Parameters:

path - The FS path of the directory

Returns:

0 on success, a negative value on error

statfs

public int statfs(String path,
                  ru.serce.jnrfuse.struct.Statvfs stbuf)

Gets the filesystem statistics.

Specified by:

statfs in interface ru.serce.jnrfuse.FuseFS

Overrides:

statfs in class ru.serce.jnrfuse.FuseStubFS

Parameters:

path - The FS path of the directory

stbuf - Statistics of a filesystem

Returns:

0 on success, a negative value on error

truncate

public int truncate(String path,
                    long size)

Changes the size of a file. This operation would not succeed because of Alluxio's write-once model.

Specified by:

truncate in interface ru.serce.jnrfuse.FuseFS

Overrides:

truncate in class ru.serce.jnrfuse.FuseStubFS

unlink

public int unlink(String path)

Deletes a file from the FS.

Specified by:

unlink in interface ru.serce.jnrfuse.FuseFS

Overrides:

unlink in class ru.serce.jnrfuse.FuseStubFS

Parameters:

path - the FS path of the file

Returns:

0 on success, a negative value on error

utimens

public int utimens(String path,
                   ru.serce.jnrfuse.struct.Timespec[] timespec)

Alluxio does not have access time, and the file is created only once. So this operation is a no-op.

Specified by:

utimens in interface ru.serce.jnrfuse.FuseFS

Overrides:

utimens in class ru.serce.jnrfuse.FuseStubFS

write

public int write(String path,
                 jnr.ffi.Pointer buf,
                 long size,
                 long offset,
                 ru.serce.jnrfuse.struct.FuseFileInfo fi)

Writes a buffer to an open Alluxio file. Random write is not supported, so the offset argument is ignored. Also, due to an issue in OSXFUSE that may write the same content at a offset multiple times, the write also checks that the subsequent write of the same offset is ignored.

Specified by:

write in interface ru.serce.jnrfuse.FuseFS

Overrides:

write in class ru.serce.jnrfuse.FuseStubFS

Parameters:

buf - The buffer with source data

size - How much data to write from the buffer. The maximum accepted size for writes is Integer.MAX_VALUE. Note that current FUSE implementation will anyway call write with at most 128K writes

offset - The offset where to write in the file (IGNORED)

fi - FileInfo data structure kept by FUSE

Returns:

number of bytes written on success, a negative value on error

mount

public void mount(Path mountPoint,
                  boolean blocking,
                  boolean debug,
                  String[] fuseOpts)

Specified by:

mount in interface ru.serce.jnrfuse.Mountable

Overrides:

mount in class ru.serce.jnrfuse.AbstractFuseFS

umount

public void umount(boolean force)

Description copied from interface: FuseUmountable

Unmounts the Fuse application.

Specified by:

umount in interface FuseUmountable

Parameters:

force - true to throw an exception and treat umount as a no-op when umount timeouts due to the fuse device is busy.