#include <fuse.h>
Data Fields | |
| int(* | getattr )(const char *, struct stat *) |
| int(* | readlink )(const char *, char *, size_t) |
| int(* | mknod )(const char *, mode_t, dev_t) |
| int(* | mkdir )(const char *, mode_t) |
| int(* | unlink )(const char *) |
| int(* | rmdir )(const char *) |
| int(* | symlink )(const char *, const char *) |
| int(* | rename )(const char *, const char *) |
| int(* | link )(const char *, const char *) |
| int(* | chmod )(const char *, mode_t) |
| int(* | chown )(const char *, uid_t, gid_t) |
| int(* | truncate )(const char *, off_t) |
| int(* | utime )(const char *, struct utimbuf *) |
| int(* | open )(const char *, struct fuse_file_info *) |
| int(* | read )(const char *, char *, size_t, off_t, struct fuse_file_info *) |
| int(* | write )(const char *, const char *, size_t, off_t, struct fuse_file_info *) |
| int(* | statfs )(const char *, struct statvfs *) |
| int(* | flush )(const char *, struct fuse_file_info *) |
| int(* | release )(const char *, struct fuse_file_info *) |
| int(* | fsync )(const char *, int, struct fuse_file_info *) |
| int(* | setxattr )(const char *, const char *, const char *, size_t, int) |
| int(* | getxattr )(const char *, const char *, char *, size_t) |
| int(* | listxattr )(const char *, char *, size_t) |
| int(* | removexattr )(const char *, const char *) |
| int(* | opendir )(const char *, struct fuse_file_info *) |
| int(* | readdir )(const char *, void *, fuse_fill_dir_t, off_t, struct fuse_file_info *) |
| int(* | releasedir )(const char *, struct fuse_file_info *) |
| int(* | fsyncdir )(const char *, int, struct fuse_file_info *) |
| void *(* | init )(struct fuse_conn_info *conn) |
| void(* | destroy )(void *) |
| int(* | access )(const char *, int) |
| int(* | create )(const char *, mode_t, struct fuse_file_info *) |
| int(* | ftruncate )(const char *, off_t, struct fuse_file_info *) |
| int(* | fgetattr )(const char *, struct stat *, struct fuse_file_info *) |
| int(* | lock )(const char *, struct fuse_file_info *, int cmd, struct flock *) |
| int(* | utimens )(const char *, const struct timespec tv[2]) |
| int(* | bmap )(const char *, size_t blocksize, uint64_t *idx) |
Most of these should work very similarly to the well known UNIX file system operations. A major exception is that instead of returning an error in 'errno', the operation should return the negated error value (-errno) directly.
All methods are optional, but some are essential for a useful filesystem (e.g. getattr). Open, flush, release, fsync, opendir, releasedir, fsyncdir, access, create, ftruncate, fgetattr, lock, init and destroy are special purpose methods, without which a full featured filesystem can still be implemented.
| int(* fuse_operations::getattr)(const char *, struct stat *) |
Get file attributes.
Similar to stat(). The 'st_dev' and 'st_blksize' fields are ignored. The 'st_ino' field is ignored except if the 'use_ino' mount option is given.
| int(* fuse_operations::readlink)(const char *, char *, size_t) |
Read the target of a symbolic link
The buffer should be filled with a null terminated string. The buffer size argument includes the space for the terminating null character. If the linkname is too long to fit in the buffer, it should be truncated. The return value should be 0 for success.
| int(* fuse_operations::mknod)(const char *, mode_t, dev_t) |
Create a file node
This is called for creation of all non-directory, non-symlink nodes. If the filesystem defines a create() method, then for regular files that will be called instead.
| int(* fuse_operations::mkdir)(const char *, mode_t) |
Create a directory
| int(* fuse_operations::unlink)(const char *) |
Remove a file
| int(* fuse_operations::rmdir)(const char *) |
Remove a directory
| int(* fuse_operations::symlink)(const char *, const char *) |
Create a symbolic link
| int(* fuse_operations::rename)(const char *, const char *) |
Rename a file
| int(* fuse_operations::link)(const char *, const char *) |
Create a hard link to a file
| int(* fuse_operations::chmod)(const char *, mode_t) |
Change the permission bits of a file
| int(* fuse_operations::chown)(const char *, uid_t, gid_t) |
Change the owner and group of a file
| int(* fuse_operations::truncate)(const char *, off_t) |
Change the size of a file
| int(* fuse_operations::utime)(const char *, struct utimbuf *) |
Change the access and/or modification times of a file
Deprecated, use utimens() instead.
| int(* fuse_operations::open)(const char *, struct fuse_file_info *) |
File open operation
No creation, or truncation flags (O_CREAT, O_EXCL, O_TRUNC) will be passed to open(). Open should check if the operation is permitted for the given flags. Optionally open may also return an arbitrary filehandle in the fuse_file_info structure, which will be passed to all file operations.
Changed in version 2.2
| int(* fuse_operations::read)(const char *, char *, size_t, off_t, struct fuse_file_info *) |
Read data from an open file
Read should return exactly the number of bytes requested except on EOF or error, otherwise the rest of the data will be substituted with zeroes. An exception to this is when the 'direct_io' mount option is specified, in which case the return value of the read system call will reflect the return value of this operation.
Changed in version 2.2
| int(* fuse_operations::write)(const char *, const char *, size_t, off_t, struct fuse_file_info *) |
Write data to an open file
Write should return exactly the number of bytes requested except on error. An exception to this is when the 'direct_io' mount option is specified (see read operation).
Changed in version 2.2
| int(* fuse_operations::statfs)(const char *, struct statvfs *) |
Get file system statistics
The 'f_frsize', 'f_favail', 'f_fsid' and 'f_flag' fields are ignored
Replaced 'struct statfs' parameter with 'struct statvfs' in version 2.5
| int(* fuse_operations::flush)(const char *, struct fuse_file_info *) |
Possibly flush cached data
BIG NOTE: This is not equivalent to fsync(). It's not a request to sync dirty data.
Flush is called on each close() of a file descriptor. So if a filesystem wants to return write errors in close() and the file has cached dirty data, this is a good place to write back data and return any errors. Since many applications ignore close() errors this is not always useful.
NOTE: The flush() method may be called more than once for each open(). This happens if more than one file descriptor refers to an opened file due to dup(), dup2() or fork() calls. It is not possible to determine if a flush is final, so each flush should be treated equally. Multiple write-flush sequences are relatively rare, so this shouldn't be a problem.
Filesystems shouldn't assume that flush will always be called after some writes, or that if will be called at all.
Changed in version 2.2
| int(* fuse_operations::release)(const char *, struct fuse_file_info *) |
Release an open file
Release is called when there are no more references to an open file: all file descriptors are closed and all memory mappings are unmapped.
For every open() call there will be exactly one release() call with the same flags and file descriptor. It is possible to have a file opened more than once, in which case only the last release will mean, that no more reads/writes will happen on the file. The return value of release is ignored.
Changed in version 2.2
| int(* fuse_operations::fsync)(const char *, int, struct fuse_file_info *) |
Synchronize file contents
If the datasync parameter is non-zero, then only the user data should be flushed, not the meta data.
Changed in version 2.2
| int(* fuse_operations::setxattr)(const char *, const char *, const char *, size_t, int) |
Set extended attributes
| int(* fuse_operations::getxattr)(const char *, const char *, char *, size_t) |
Get extended attributes
| int(* fuse_operations::listxattr)(const char *, char *, size_t) |
List extended attributes
| int(* fuse_operations::removexattr)(const char *, const char *) |
Remove extended attributes
| int(* fuse_operations::opendir)(const char *, struct fuse_file_info *) |
Open directory
This method should check if the open operation is permitted for this directory
Introduced in version 2.3
| int(* fuse_operations::readdir)(const char *, void *, fuse_fill_dir_t, off_t, struct fuse_file_info *) |
Read directory
This supersedes the old getdir() interface. New applications should use this.
The filesystem may choose between two modes of operation:
1) The readdir implementation ignores the offset parameter, and passes zero to the filler function's offset. The filler function will not return '1' (unless an error happens), so the whole directory is read in a single readdir operation. This works just like the old getdir() method.
2) The readdir implementation keeps track of the offsets of the directory entries. It uses the offset parameter and always passes non-zero offset to the filler function. When the buffer is full (or an error happens) the filler function will return '1'.
Introduced in version 2.3
| int(* fuse_operations::releasedir)(const char *, struct fuse_file_info *) |
Release directory
Introduced in version 2.3
| int(* fuse_operations::fsyncdir)(const char *, int, struct fuse_file_info *) |
Synchronize directory contents
If the datasync parameter is non-zero, then only the user data should be flushed, not the meta data
Introduced in version 2.3
| void*(* fuse_operations::init)(struct fuse_conn_info *conn) |
Initialize filesystem
The return value will passed in the private_data field of fuse_context to all file operations and as a parameter to the destroy() method.
Introduced in version 2.3 Changed in version 2.6
| void(* fuse_operations::destroy)(void *) |
Clean up filesystem
Called on filesystem exit.
Introduced in version 2.3
| int(* fuse_operations::access)(const char *, int) |
Check file access permissions
This will be called for the access() system call. If the 'default_permissions' mount option is given, this method is not called.
This method is not called under Linux kernel versions 2.4.x
Introduced in version 2.5
| int(* fuse_operations::create)(const char *, mode_t, struct fuse_file_info *) |
| int(* fuse_operations::ftruncate)(const char *, off_t, struct fuse_file_info *) |
Change the size of an open file
This method is called instead of the truncate() method if the truncation was invoked from an ftruncate() system call.
If this method is not implemented or under Linux kernel versions earlier than 2.6.15, the truncate() method will be called instead.
Introduced in version 2.5
| int(* fuse_operations::fgetattr)(const char *, struct stat *, struct fuse_file_info *) |
| int(* fuse_operations::lock)(const char *, struct fuse_file_info *, int cmd, struct flock *) |
Perform POSIX file locking operation
The cmd argument will be either F_GETLK, F_SETLK or F_SETLKW.
For the meaning of fields in 'struct flock' see the man page for fcntl(2). The l_whence field will always be set to SEEK_SET.
For checking lock ownership, the 'fuse_file_info->owner' argument must be used.
For F_GETLK operation, the library will first check currently held locks, and if a conflicting lock is found it will return information without calling this method. This ensures, that for local locks the l_pid field is correctly filled in. The results may not be accurate in case of race conditions and in the presence of hard links, but it's unlikly that an application would rely on accurate GETLK results in these cases. If a conflicting lock is not found, this method will be called, and the filesystem may fill out l_pid by a meaningful value, or it may leave this field zero.
For F_SETLK and F_SETLKW the l_pid field will be set to the pid of the process performing the locking operation.
Note: if this method is not implemented, the kernel will still allow file locking to work locally. Hence it is only interesting for network filesystems and similar.
Introduced in version 2.6
| int(* fuse_operations::utimens)(const char *, const struct timespec tv[2]) |
Change the access and modification times of a file with nanosecond resolution
Introduced in version 2.6
| int(* fuse_operations::bmap)(const char *, size_t blocksize, uint64_t *idx) |
Map block index within file to block index within device
Note: This makes sense only for block device backed filesystems mounted with the 'blkdev' option
Introduced in version 2.6
1.5.0