#include <fuse_lowlevel.h>
Data Fields | |
| void(* | init )(void *userdata, struct fuse_conn_info *conn) |
| void(* | destroy )(void *userdata) |
| void(* | lookup )(fuse_req_t req, fuse_ino_t parent, const char *name) |
| void(* | forget )(fuse_req_t req, fuse_ino_t ino, unsigned long nlookup) |
| void(* | getattr )(fuse_req_t req, fuse_ino_t ino, struct fuse_file_info *fi) |
| void(* | setattr )(fuse_req_t req, fuse_ino_t ino, struct stat *attr, int to_set, struct fuse_file_info *fi) |
| void(* | readlink )(fuse_req_t req, fuse_ino_t ino) |
| void(* | mknod )(fuse_req_t req, fuse_ino_t parent, const char *name, mode_t mode, dev_t rdev) |
| void(* | mkdir )(fuse_req_t req, fuse_ino_t parent, const char *name, mode_t mode) |
| void(* | unlink )(fuse_req_t req, fuse_ino_t parent, const char *name) |
| void(* | rmdir )(fuse_req_t req, fuse_ino_t parent, const char *name) |
| void(* | symlink )(fuse_req_t req, const char *link, fuse_ino_t parent, const char *name) |
| void(* | rename )(fuse_req_t req, fuse_ino_t parent, const char *name, fuse_ino_t newparent, const char *newname) |
| void(* | link )(fuse_req_t req, fuse_ino_t ino, fuse_ino_t newparent, const char *newname) |
| void(* | open )(fuse_req_t req, fuse_ino_t ino, struct fuse_file_info *fi) |
| void(* | read )(fuse_req_t req, fuse_ino_t ino, size_t size, off_t off, struct fuse_file_info *fi) |
| void(* | write )(fuse_req_t req, fuse_ino_t ino, const char *buf, size_t size, off_t off, struct fuse_file_info *fi) |
| void(* | flush )(fuse_req_t req, fuse_ino_t ino, struct fuse_file_info *fi) |
| void(* | release )(fuse_req_t req, fuse_ino_t ino, struct fuse_file_info *fi) |
| void(* | fsync )(fuse_req_t req, fuse_ino_t ino, int datasync, struct fuse_file_info *fi) |
| void(* | opendir )(fuse_req_t req, fuse_ino_t ino, struct fuse_file_info *fi) |
| void(* | readdir )(fuse_req_t req, fuse_ino_t ino, size_t size, off_t off, struct fuse_file_info *fi) |
| void(* | releasedir )(fuse_req_t req, fuse_ino_t ino, struct fuse_file_info *fi) |
| void(* | fsyncdir )(fuse_req_t req, fuse_ino_t ino, int datasync, struct fuse_file_info *fi) |
| void(* | statfs )(fuse_req_t req, fuse_ino_t ino) |
| void(* | setxattr )(fuse_req_t req, fuse_ino_t ino, const char *name, const char *value, size_t size, int flags) |
| void(* | getxattr )(fuse_req_t req, fuse_ino_t ino, const char *name, size_t size) |
| void(* | listxattr )(fuse_req_t req, fuse_ino_t ino, size_t size) |
| void(* | removexattr )(fuse_req_t req, fuse_ino_t ino, const char *name) |
| void(* | access )(fuse_req_t req, fuse_ino_t ino, int mask) |
| void(* | create )(fuse_req_t req, fuse_ino_t parent, const char *name, mode_t mode, struct fuse_file_info *fi) |
| void(* | getlk )(fuse_req_t req, fuse_ino_t ino, struct fuse_file_info *fi, struct flock *lock) |
| void(* | setlk )(fuse_req_t req, fuse_ino_t ino, struct fuse_file_info *fi, struct flock *lock, int sleep) |
| void(* | bmap )(fuse_req_t req, fuse_ino_t ino, size_t blocksize, uint64_t idx) |
Most of the methods (with the exception of init and destroy) receive a request handle (fuse_req_t) as their first argument. This handle must be passed to one of the specified reply functions.
This may be done inside the method invocation, or after the call has returned. The request handle is valid until one of the reply functions is called.
Other pointer arguments (name, fuse_file_info, etc) are not valid after the call has returned, so if they are needed later, their contents have to be copied.
The filesystem sometimes needs to handle a return value of -ENOENT from the reply function, which means, that the request was interrupted, and the reply discarded. For example if fuse_reply_open() return -ENOENT means, that the release method for this file will not be called.
| void(* fuse_lowlevel_ops::init)(void *userdata, struct fuse_conn_info *conn) |
Initialize filesystem
Called before any other filesystem method
There's no reply to this function
| userdata | the user data passed to fuse_lowlevel_new() |
| void(* fuse_lowlevel_ops::destroy)(void *userdata) |
Clean up filesystem
Called on filesystem exit
There's no reply to this function
| userdata | the user data passed to fuse_lowlevel_new() |
| void(* fuse_lowlevel_ops::lookup)(fuse_req_t req, fuse_ino_t parent, const char *name) |
Look up a directory entry by name
Valid replies: fuse_reply_entry fuse_reply_err
| req | request handle | |
| parent | inode number of the parent directory | |
| name | the name to look up |
| void(* fuse_lowlevel_ops::forget)(fuse_req_t req, fuse_ino_t ino, unsigned long nlookup) |
Forget about an inode
The nlookup parameter indicates the number of lookups previously performed on this inode.
If the filesystem implements inode lifetimes, it is recommended that inodes acquire a single reference on each lookup, and lose nlookup references on each forget.
The filesystem may ignore forget calls, if the inodes don't need to have a limited lifetime.
On unmount it is not guaranteed, that all referenced inodes will receive a forget message.
Valid replies: fuse_reply_none
| req | request handle | |
| ino | the inode number | |
| nlookup | the number of lookups to forget |
| void(* fuse_lowlevel_ops::getattr)(fuse_req_t req, fuse_ino_t ino, struct fuse_file_info *fi) |
Get file attributes
Valid replies: fuse_reply_attr fuse_reply_err
| req | request handle | |
| ino | the inode number | |
| fi | for future use, currently always NULL |
| void(* fuse_lowlevel_ops::setattr)(fuse_req_t req, fuse_ino_t ino, struct stat *attr, int to_set, struct fuse_file_info *fi) |
Set file attributes
In the 'attr' argument only members indicated by the 'to_set' bitmask contain valid values. Other members contain undefined values.
If the setattr was invoked from the ftruncate() system call under Linux kernel versions 2.6.15 or later, the fi->fh will contain the value set by the open method or will be undefined if the open method didn't set any value. Otherwise (not ftruncate call, or kernel version earlier than 2.6.15) the fi parameter will be NULL.
Valid replies: fuse_reply_attr fuse_reply_err
| req | request handle | |
| ino | the inode number | |
| attr | the attributes | |
| to_set | bit mask of attributes which should be set | |
| fi | file information, or NULL |
| void(* fuse_lowlevel_ops::readlink)(fuse_req_t req, fuse_ino_t ino) |
Read symbolic link
Valid replies: fuse_reply_readlink fuse_reply_err
| req | request handle | |
| ino | the inode number |
| void(* fuse_lowlevel_ops::mknod)(fuse_req_t req, fuse_ino_t parent, const char *name, mode_t mode, dev_t rdev) |
Create file node
Create a regular file, character device, block device, fifo or socket node.
Valid replies: fuse_reply_entry fuse_reply_err
| req | request handle | |
| parent | inode number of the parent directory | |
| name | to create | |
| mode | file type and mode with which to create the new file | |
| rdev | the device number (only valid if created file is a device) |
| void(* fuse_lowlevel_ops::mkdir)(fuse_req_t req, fuse_ino_t parent, const char *name, mode_t mode) |
Create a directory
Valid replies: fuse_reply_entry fuse_reply_err
| req | request handle | |
| parent | inode number of the parent directory | |
| name | to create | |
| mode | with which to create the new file |
| void(* fuse_lowlevel_ops::unlink)(fuse_req_t req, fuse_ino_t parent, const char *name) |
Remove a file
Valid replies: fuse_reply_err
| req | request handle | |
| parent | inode number of the parent directory | |
| name | to remove |
| void(* fuse_lowlevel_ops::rmdir)(fuse_req_t req, fuse_ino_t parent, const char *name) |
Remove a directory
Valid replies: fuse_reply_err
| req | request handle | |
| parent | inode number of the parent directory | |
| name | to remove |
| void(* fuse_lowlevel_ops::symlink)(fuse_req_t req, const char *link, fuse_ino_t parent, const char *name) |
Create a symbolic link
Valid replies: fuse_reply_entry fuse_reply_err
| req | request handle | |
| link | the contents of the symbolic link | |
| parent | inode number of the parent directory | |
| name | to create |
| void(* fuse_lowlevel_ops::rename)(fuse_req_t req, fuse_ino_t parent, const char *name, fuse_ino_t newparent, const char *newname) |
Rename a file
Valid replies: fuse_reply_err
| req | request handle | |
| parent | inode number of the old parent directory | |
| name | old name | |
| newparent | inode number of the new parent directory | |
| newname | new name |
| void(* fuse_lowlevel_ops::link)(fuse_req_t req, fuse_ino_t ino, fuse_ino_t newparent, const char *newname) |
Create a hard link
Valid replies: fuse_reply_entry fuse_reply_err
| req | request handle | |
| ino | the old inode number | |
| newparent | inode number of the new parent directory | |
| newname | new name to create |
| void(* fuse_lowlevel_ops::open)(fuse_req_t req, fuse_ino_t ino, struct fuse_file_info *fi) |
Open a file
Open flags (with the exception of O_CREAT, O_EXCL, O_NOCTTY and O_TRUNC) are available in fi->flags.
Filesystem may store an arbitrary file handle (pointer, index, etc) in fi->fh, and use this in other all other file operations (read, write, flush, release, fsync).
Filesystem may also implement stateless file I/O and not store anything in fi->fh.
There are also some flags (direct_io, keep_cache) which the filesystem may set in fi, to change the way the file is opened. See fuse_file_info structure in <fuse_common.h> for more details.
Valid replies: fuse_reply_open fuse_reply_err
| req | request handle | |
| ino | the inode number | |
| fi | file information |
| void(* fuse_lowlevel_ops::read)(fuse_req_t req, fuse_ino_t ino, size_t size, off_t off, struct fuse_file_info *fi) |
Read data
Read should send 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 file has been opened in 'direct_io' mode, in which case the return value of the read system call will reflect the return value of this operation.
fi->fh will contain the value set by the open method, or will be undefined if the open method didn't set any value.
Valid replies: fuse_reply_buf fuse_reply_err
| req | request handle | |
| ino | the inode number | |
| size | number of bytes to read | |
| off | offset to read from | |
| fi | file information |
| void(* fuse_lowlevel_ops::write)(fuse_req_t req, fuse_ino_t ino, const char *buf, size_t size, off_t off, struct fuse_file_info *fi) |
Write data
Write should return exactly the number of bytes requested except on error. An exception to this is when the file has been opened in 'direct_io' mode, in which case the return value of the write system call will reflect the return value of this operation.
fi->fh will contain the value set by the open method, or will be undefined if the open method didn't set any value.
Valid replies: fuse_reply_write fuse_reply_err
| req | request handle | |
| ino | the inode number | |
| buf | data to write | |
| size | number of bytes to write | |
| off | offset to write to | |
| fi | file information |
| void(* fuse_lowlevel_ops::flush)(fuse_req_t req, fuse_ino_t ino, struct fuse_file_info *fi) |
Flush method
This is called on each close() of the opened file.
Since file descriptors can be duplicated (dup, dup2, fork), for one open call there may be many flush calls.
Filesystems shouldn't assume that flush will always be called after some writes, or that if will be called at all.
fi->fh will contain the value set by the open method, or will be undefined if the open method didn't set any value.
NOTE: the name of the method is misleading, since (unlike fsync) the filesystem is not forced to flush pending writes. One reason to flush data, is if the filesystem wants to return write errors.
If the filesystem supports file locking operations (setlk, getlk) it should remove all locks belonging to 'fi->owner'.
Valid replies: fuse_reply_err
| req | request handle | |
| ino | the inode number | |
| fi | file information |
| void(* fuse_lowlevel_ops::release)(fuse_req_t req, fuse_ino_t ino, struct fuse_file_info *fi) |
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.
The filesystem may reply with an error, but error values are not returned to close() or munmap() which triggered the release.
fi->fh will contain the value set by the open method, or will be undefined if the open method didn't set any value. fi->flags will contain the same flags as for open.
Valid replies: fuse_reply_err
| req | request handle | |
| ino | the inode number | |
| fi | file information |
| void(* fuse_lowlevel_ops::fsync)(fuse_req_t req, fuse_ino_t ino, int datasync, struct fuse_file_info *fi) |
Synchronize file contents
If the datasync parameter is non-zero, then only the user data should be flushed, not the meta data.
Valid replies: fuse_reply_err
| req | request handle | |
| ino | the inode number | |
| datasync | flag indicating if only data should be flushed | |
| fi | file information |
| void(* fuse_lowlevel_ops::opendir)(fuse_req_t req, fuse_ino_t ino, struct fuse_file_info *fi) |
Open a directory
Filesystem may store an arbitrary file handle (pointer, index, etc) in fi->fh, and use this in other all other directory stream operations (readdir, releasedir, fsyncdir).
Filesystem may also implement stateless directory I/O and not store anything in fi->fh, though that makes it impossible to implement standard conforming directory stream operations in case the contents of the directory can change between opendir and releasedir.
Valid replies: fuse_reply_open fuse_reply_err
| req | request handle | |
| ino | the inode number | |
| fi | file information |
| void(* fuse_lowlevel_ops::readdir)(fuse_req_t req, fuse_ino_t ino, size_t size, off_t off, struct fuse_file_info *fi) |
Read directory
Send a buffer filled using fuse_add_direntry(), with size not exceeding the requested size. Send an empty buffer on end of stream.
fi->fh will contain the value set by the opendir method, or will be undefined if the opendir method didn't set any value.
Valid replies: fuse_reply_buf fuse_reply_err
| req | request handle | |
| ino | the inode number | |
| size | maximum number of bytes to send | |
| off | offset to continue reading the directory stream | |
| fi | file information |
| void(* fuse_lowlevel_ops::releasedir)(fuse_req_t req, fuse_ino_t ino, struct fuse_file_info *fi) |
Release an open directory
For every opendir call there will be exactly one releasedir call.
fi->fh will contain the value set by the opendir method, or will be undefined if the opendir method didn't set any value.
Valid replies: fuse_reply_err
| req | request handle | |
| ino | the inode number | |
| fi | file information |
| void(* fuse_lowlevel_ops::fsyncdir)(fuse_req_t req, fuse_ino_t ino, int datasync, struct fuse_file_info *fi) |
Synchronize directory contents
If the datasync parameter is non-zero, then only the directory contents should be flushed, not the meta data.
fi->fh will contain the value set by the opendir method, or will be undefined if the opendir method didn't set any value.
Valid replies: fuse_reply_err
| req | request handle | |
| ino | the inode number | |
| datasync | flag indicating if only data should be flushed | |
| fi | file information |
| void(* fuse_lowlevel_ops::statfs)(fuse_req_t req, fuse_ino_t ino) |
Get file system statistics
Valid replies: fuse_reply_statfs fuse_reply_err
| req | request handle | |
| ino | the inode number, zero means "undefined" |
| void(* fuse_lowlevel_ops::setxattr)(fuse_req_t req, fuse_ino_t ino, const char *name, const char *value, size_t size, int flags) |
Set an extended attribute
Valid replies: fuse_reply_err
| void(* fuse_lowlevel_ops::getxattr)(fuse_req_t req, fuse_ino_t ino, const char *name, size_t size) |
Get an extended attribute
If size is zero, the size of the value should be sent with fuse_reply_xattr.
If the size is non-zero, and the value fits in the buffer, the value should be sent with fuse_reply_buf.
If the size is too small for the value, the ERANGE error should be sent.
Valid replies: fuse_reply_buf fuse_reply_xattr fuse_reply_err
| req | request handle | |
| ino | the inode number | |
| name | of the extended attribute | |
| size | maximum size of the value to send |
| void(* fuse_lowlevel_ops::listxattr)(fuse_req_t req, fuse_ino_t ino, size_t size) |
List extended attribute names
If size is zero, the total size of the attribute list should be sent with fuse_reply_xattr.
If the size is non-zero, and the null character separated attribute list fits in the buffer, the list should be sent with fuse_reply_buf.
If the size is too small for the list, the ERANGE error should be sent.
Valid replies: fuse_reply_buf fuse_reply_xattr fuse_reply_err
| req | request handle | |
| ino | the inode number | |
| size | maximum size of the list to send |
| void(* fuse_lowlevel_ops::removexattr)(fuse_req_t req, fuse_ino_t ino, const char *name) |
Remove an extended attribute
Valid replies: fuse_reply_err
| req | request handle | |
| ino | the inode number | |
| name | of the extended attribute |
| void(* fuse_lowlevel_ops::access)(fuse_req_t req, fuse_ino_t ino, int mask) |
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
Valid replies: fuse_reply_err
| req | request handle | |
| ino | the inode number | |
| mask | requested access mode |
| void(* fuse_lowlevel_ops::create)(fuse_req_t req, fuse_ino_t parent, const char *name, mode_t mode, struct fuse_file_info *fi) |
Create and open a file
If the file does not exist, first create it with the specified mode, and then open it.
Open flags (with the exception of O_NOCTTY) are available in fi->flags.
Filesystem may store an arbitrary file handle (pointer, index, etc) in fi->fh, and use this in other all other file operations (read, write, flush, release, fsync).
There are also some flags (direct_io, keep_cache) which the filesystem may set in fi, to change the way the file is opened. See fuse_file_info structure in <fuse_common.h> for more details.
If this method is not implemented or under Linux kernel versions earlier than 2.6.15, the mknod() and open() methods will be called instead.
Introduced in version 2.5
Valid replies: fuse_reply_create fuse_reply_err
| req | request handle | |
| parent | inode number of the parent directory | |
| name | to create | |
| mode | file type and mode with which to create the new file | |
| fi | file information |
| void(* fuse_lowlevel_ops::getlk)(fuse_req_t req, fuse_ino_t ino, struct fuse_file_info *fi, struct flock *lock) |
Test for a POSIX file lock
Introduced in version 2.6
Valid replies: fuse_reply_lock fuse_reply_err
| req | request handle | |
| ino | the inode number | |
| fi | file information | |
| lock | the region/type to test |
| void(* fuse_lowlevel_ops::setlk)(fuse_req_t req, fuse_ino_t ino, struct fuse_file_info *fi, struct flock *lock, int sleep) |
Acquire, modify or release a POSIX file lock
For POSIX threads (NPTL) there's a 1-1 relation between pid and owner, but otherwise this is not always the case. For checking lock ownership, 'fi->owner' must be used. The l_pid field in 'struct flock' should only be used to fill in this field in getlk().
Note: if the locking methods are not implemented, the kernel will still allow file locking to work locally. Hence these are only interesting for network filesystems and similar.
Introduced in version 2.6
Valid replies: fuse_reply_err
| req | request handle | |
| ino | the inode number | |
| fi | file information | |
| lock | the region/type to test | |
| sleep | locking operation may sleep |
| void(* fuse_lowlevel_ops::bmap)(fuse_req_t req, fuse_ino_t ino, 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
Valid replies: fuse_reply_bmap fuse_reply_err
| req | request handle | |
| ino | the inode number | |
| blocksize | unit of block index | |
| idx | block index within file |
1.5.0