[−][src]Struct libfuse_sys::fuse_lowlevel::fuse_lowlevel_ops
Low level filesystem operations
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.
Fields
init: Option<unsafe extern "C" fn(userdata: *mut c_void, conn: *mut fuse_conn_info)>Initialize filesystem
Called before any other filesystem method
There's no reply to this function
@param userdata the user data passed to fuse_lowlevel_new()
destroy: Option<unsafe extern "C" fn(userdata: *mut c_void)>Clean up filesystem
Called on filesystem exit
There's no reply to this function
@param userdata the user data passed to fuse_lowlevel_new()
lookup: Option<unsafe extern "C" fn(req: fuse_req_t, parent: fuse_ino_t, name: *const c_char)>Look up a directory entry by name and get its attributes.
Valid replies: fuse_reply_entry fuse_reply_err
@param req request handle @param parent inode number of the parent directory @param name the name to look up
forget: Option<unsafe extern "C" fn(req: fuse_req_t, ino: fuse_ino_t, nlookup: c_ulong)>Forget about an inode
This function is called when the kernel removes an inode from its internal caches.
The inode's lookup count increases by one for every call to fuse_reply_entry and fuse_reply_create. The nlookup parameter indicates by how much the lookup count should be decreased.
Inodes with a non-zero lookup count may receive request from the kernel even after calls to unlink, rmdir or (when overwriting an existing file) rename. Filesystems must handle such requests properly and it is recommended to defer removal of the inode until the lookup count reaches zero. Calls to unlink, remdir or rename will be followed closely by forget unless the file or directory is open, in which case the kernel issues forget only after the release or releasedir calls.
Note that if a file system will be exported over NFS the inodes lifetime must extend even beyond forget. See the generation field in struct fuse_entry_param above.
On unmount the lookup count for all inodes implicitly drops to zero. It is not guaranteed that the file system will receive corresponding forget messages for the affected inodes.
Valid replies: fuse_reply_none
@param req request handle @param ino the inode number @param nlookup the number of lookups to forget
getattr: Option<unsafe extern "C" fn(req: fuse_req_t, ino: fuse_ino_t, fi: *mut fuse_file_info)>Get file attributes
Valid replies: fuse_reply_attr fuse_reply_err
@param req request handle @param ino the inode number @param fi for future use, currently always NULL
setattr: Option<unsafe extern "C" fn(req: fuse_req_t, ino: fuse_ino_t, attr: *mut stat, to_set: c_int, fi: *mut fuse_file_info)>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
@param req request handle @param ino the inode number @param attr the attributes @param to_set bit mask of attributes which should be set @param fi file information, or NULL
Changed in version 2.5: file information filled in for ftruncate
readlink: Option<unsafe extern "C" fn(req: fuse_req_t, ino: fuse_ino_t)>Read symbolic link
Valid replies: fuse_reply_readlink fuse_reply_err
@param req request handle @param ino the inode number
mknod: Option<unsafe extern "C" fn(req: fuse_req_t, parent: fuse_ino_t, name: *const c_char, mode: mode_t, rdev: dev_t)>Create file node
Create a regular file, character device, block device, fifo or socket node.
Valid replies: fuse_reply_entry fuse_reply_err
@param req request handle @param parent inode number of the parent directory @param name to create @param mode file type and mode with which to create the new file @param rdev the device number (only valid if created file is a device)
mkdir: Option<unsafe extern "C" fn(req: fuse_req_t, parent: fuse_ino_t, name: *const c_char, mode: mode_t)>Create a directory
Valid replies: fuse_reply_entry fuse_reply_err
@param req request handle @param parent inode number of the parent directory @param name to create @param mode with which to create the new file
unlink: Option<unsafe extern "C" fn(req: fuse_req_t, parent: fuse_ino_t, name: *const c_char)>Remove a file
If the file's inode's lookup count is non-zero, the file system is expected to postpone any removal of the inode until the lookup count reaches zero (see description of the forget function).
Valid replies: fuse_reply_err
@param req request handle @param parent inode number of the parent directory @param name to remove
rmdir: Option<unsafe extern "C" fn(req: fuse_req_t, parent: fuse_ino_t, name: *const c_char)>Remove a directory
If the directory's inode's lookup count is non-zero, the file system is expected to postpone any removal of the inode until the lookup count reaches zero (see description of the forget function).
Valid replies: fuse_reply_err
@param req request handle @param parent inode number of the parent directory @param name to remove
symlink: Option<unsafe extern "C" fn(req: fuse_req_t, link: *const c_char, parent: fuse_ino_t, name: *const c_char)>Create a symbolic link
Valid replies: fuse_reply_entry fuse_reply_err
@param req request handle @param link the contents of the symbolic link @param parent inode number of the parent directory @param name to create
rename: Option<unsafe extern "C" fn(req: fuse_req_t, parent: fuse_ino_t, name: *const c_char, newparent: fuse_ino_t, newname: *const c_char)>Rename a file
If the target exists it should be atomically replaced. If the target's inode's lookup count is non-zero, the file system is expected to postpone any removal of the inode until the lookup count reaches zero (see description of the forget function).
Valid replies: fuse_reply_err
@param req request handle @param parent inode number of the old parent directory @param name old name @param newparent inode number of the new parent directory @param newname new name
link: Option<unsafe extern "C" fn(req: fuse_req_t, ino: fuse_ino_t, newparent: fuse_ino_t, newname: *const c_char)>Create a hard link
Valid replies: fuse_reply_entry fuse_reply_err
@param req request handle @param ino the old inode number @param newparent inode number of the new parent directory @param newname new name to create
open: Option<unsafe extern "C" fn(req: fuse_req_t, ino: fuse_ino_t, fi: *mut fuse_file_info)>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
@param req request handle @param ino the inode number @param fi file information
read: Option<unsafe extern "C" fn(req: fuse_req_t, ino: fuse_ino_t, size: usize, off: off_t, fi: *mut fuse_file_info)>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_iov fuse_reply_data fuse_reply_err
@param req request handle @param ino the inode number @param size number of bytes to read @param off offset to read from @param fi file information
write: Option<unsafe extern "C" fn(req: fuse_req_t, ino: fuse_ino_t, buf: *const c_char, size: usize, off: off_t, fi: *mut fuse_file_info)>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
@param req request handle @param ino the inode number @param buf data to write @param size number of bytes to write @param off offset to write to @param fi file information
flush: Option<unsafe extern "C" fn(req: fuse_req_t, ino: fuse_ino_t, fi: *mut fuse_file_info)>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
@param req request handle @param ino the inode number @param fi file information
release: Option<unsafe extern "C" fn(req: fuse_req_t, ino: fuse_ino_t, fi: *mut 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.
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
@param req request handle @param ino the inode number @param fi file information
fsync: Option<unsafe extern "C" fn(req: fuse_req_t, ino: fuse_ino_t, datasync: c_int, fi: *mut 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.
Valid replies: fuse_reply_err
@param req request handle @param ino the inode number @param datasync flag indicating if only data should be flushed @param fi file information
opendir: Option<unsafe extern "C" fn(req: fuse_req_t, ino: fuse_ino_t, fi: *mut fuse_file_info)>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
@param req request handle @param ino the inode number @param fi file information
readdir: Option<unsafe extern "C" fn(req: fuse_req_t, ino: fuse_ino_t, size: usize, off: off_t, fi: *mut fuse_file_info)>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_data fuse_reply_err
@param req request handle @param ino the inode number @param size maximum number of bytes to send @param off offset to continue reading the directory stream @param fi file information
releasedir: Option<unsafe extern "C" fn(req: fuse_req_t, ino: fuse_ino_t, fi: *mut fuse_file_info)>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
@param req request handle @param ino the inode number @param fi file information
fsyncdir: Option<unsafe extern "C" fn(req: fuse_req_t, ino: fuse_ino_t, datasync: c_int, fi: *mut fuse_file_info)>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
@param req request handle @param ino the inode number @param datasync flag indicating if only data should be flushed @param fi file information
statfs: Option<unsafe extern "C" fn(req: fuse_req_t, ino: fuse_ino_t)>Get file system statistics
Valid replies: fuse_reply_statfs fuse_reply_err
@param req request handle @param ino the inode number, zero means "undefined"
setxattr: Option<unsafe extern "C" fn(req: fuse_req_t, ino: fuse_ino_t, name: *const c_char, value: *const c_char, size: usize, flags: c_int)>Set an extended attribute
Valid replies: fuse_reply_err
getxattr: Option<unsafe extern "C" fn(req: fuse_req_t, ino: fuse_ino_t, name: *const c_char, size: usize)>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_data fuse_reply_xattr fuse_reply_err
@param req request handle @param ino the inode number @param name of the extended attribute @param size maximum size of the value to send
listxattr: Option<unsafe extern "C" fn(req: fuse_req_t, ino: fuse_ino_t, size: usize)>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_data fuse_reply_xattr fuse_reply_err
@param req request handle @param ino the inode number @param size maximum size of the list to send
removexattr: Option<unsafe extern "C" fn(req: fuse_req_t, ino: fuse_ino_t, name: *const c_char)>Remove an extended attribute
Valid replies: fuse_reply_err
@param req request handle @param ino the inode number @param name of the extended attribute
access: Option<unsafe extern "C" fn(req: fuse_req_t, ino: fuse_ino_t, mask: c_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
Valid replies: fuse_reply_err
@param req request handle @param ino the inode number @param mask requested access mode
create: Option<unsafe extern "C" fn(req: fuse_req_t, parent: fuse_ino_t, name: *const c_char, mode: mode_t, fi: *mut fuse_file_info)>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
@param req request handle @param parent inode number of the parent directory @param name to create @param mode file type and mode with which to create the new file @param fi file information
getlk: Option<unsafe extern "C" fn(req: fuse_req_t, ino: fuse_ino_t, fi: *mut fuse_file_info, lock: *mut flock)>Test for a POSIX file lock
Introduced in version 2.6
Valid replies: fuse_reply_lock fuse_reply_err
@param req request handle @param ino the inode number @param fi file information @param lock the region/type to test
setlk: Option<unsafe extern "C" fn(req: fuse_req_t, ino: fuse_ino_t, fi: *mut fuse_file_info, lock: *mut flock, sleep: c_int)>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
@param req request handle @param ino the inode number @param fi file information @param lock the region/type to set @param sleep locking operation may sleep
bmap: Option<unsafe extern "C" fn(req: fuse_req_t, ino: fuse_ino_t, blocksize: usize, idx: u64)>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
@param req request handle @param ino the inode number @param blocksize unit of block index @param idx block index within file
ioctl: Option<unsafe extern "C" fn(req: fuse_req_t, ino: fuse_ino_t, cmd: c_int, arg: *mut c_void, fi: *mut fuse_file_info, flags: c_uint, in_buf: *const c_void, in_bufsz: usize, out_bufsz: usize)>Ioctl
Note: For unrestricted ioctls (not allowed for FUSE servers), data in and out areas can be discovered by giving iovs and setting FUSE_IOCTL_RETRY in @flags. For restricted ioctls, kernel prepares in/out data area according to the information encoded in cmd.
Introduced in version 2.8
Valid replies: fuse_reply_ioctl_retry fuse_reply_ioctl fuse_reply_ioctl_iov fuse_reply_err
@param req request handle @param ino the inode number @param cmd ioctl command @param arg ioctl argument @param fi file information @param flags for FUSE_IOCTL_* flags @param in_buf data fetched from the caller @param in_bufsz number of fetched bytes @param out_bufsz maximum size of output data
poll: Option<unsafe extern "C" fn(req: fuse_req_t, ino: fuse_ino_t, fi: *mut fuse_file_info, ph: *mut fuse_pollhandle)>Poll for IO readiness
Introduced in version 2.8
Note: If ph is non-NULL, the client should notify when IO readiness events occur by calling fuse_lowelevel_notify_poll() with the specified ph.
Regardless of the number of times poll with a non-NULL ph is received, single notification is enough to clear all. Notifying more times incurs overhead but doesn't harm correctness.
The callee is responsible for destroying ph with fuse_pollhandle_destroy() when no longer in use.
Valid replies: fuse_reply_poll fuse_reply_err
@param req request handle @param ino the inode number @param fi file information @param ph poll handle to be used for notification
write_buf: Option<unsafe extern "C" fn(req: fuse_req_t, ino: fuse_ino_t, bufv: *mut fuse_bufvec, off: off_t, fi: *mut fuse_file_info)>Write data made available in a buffer
This is a more generic version of the ->write() method. If FUSE_CAP_SPLICE_READ is set in fuse_conn_info.want and the kernel supports splicing from the fuse device, then the data will be made available in pipe for supporting zero copy data transfer.
buf->count is guaranteed to be one (and thus buf->idx is always zero). The write_buf handler must ensure that bufv->off is correctly updated (reflecting the number of bytes read from bufv->buf[0]).
Introduced in version 2.9
Valid replies: fuse_reply_write fuse_reply_err
@param req request handle @param ino the inode number @param bufv buffer containing the data @param off offset to write to @param fi file information
retrieve_reply: Option<unsafe extern "C" fn(req: fuse_req_t, cookie: *mut c_void, ino: fuse_ino_t, offset: off_t, bufv: *mut fuse_bufvec)>Callback function for the retrieve request
Introduced in version 2.9
Valid replies: fuse_reply_none
@param req request handle @param cookie user data supplied to fuse_lowlevel_notify_retrieve() @param ino the inode number supplied to fuse_lowlevel_notify_retrieve() @param offset the offset supplied to fuse_lowlevel_notify_retrieve() @param bufv the buffer containing the returned data
forget_multi: Option<unsafe extern "C" fn(req: fuse_req_t, count: usize, forgets: *mut fuse_forget_data)>Forget about multiple inodes
See description of the forget function for more information.
Introduced in version 2.9
Valid replies: fuse_reply_none
@param req request handle
flock: Option<unsafe extern "C" fn(req: fuse_req_t, ino: fuse_ino_t, fi: *mut fuse_file_info, op: c_int)>Acquire, modify or release a BSD file lock
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 2.9
Valid replies: fuse_reply_err
@param req request handle @param ino the inode number @param fi file information @param op the locking operation, see flock(2)
fallocate: Option<unsafe extern "C" fn(req: fuse_req_t, ino: fuse_ino_t, mode: c_int, offset: off_t, length: off_t, fi: *mut fuse_file_info)>Allocate requested space. If this function returns success then subsequent writes to the specified range shall not fail due to the lack of free space on the file system storage media.
Introduced in version 2.9
Valid replies: fuse_reply_err
@param req request handle @param ino the inode number @param offset starting point for allocated region @param length size of allocated region @param mode determines the operation to be performed on the given range, see fallocate(2)
Trait Implementations
impl Clone for fuse_lowlevel_ops[src]
fn clone(&self) -> fuse_lowlevel_ops[src]
fn clone_from(&mut self, source: &Self)1.0.0[src]
impl Copy for fuse_lowlevel_ops[src]
impl Debug for fuse_lowlevel_ops[src]
impl Default for fuse_lowlevel_ops[src]
fn default() -> fuse_lowlevel_ops[src]
Auto Trait Implementations
impl RefUnwindSafe for fuse_lowlevel_ops
impl Send for fuse_lowlevel_ops
impl Sync for fuse_lowlevel_ops
impl Unpin for fuse_lowlevel_ops
impl UnwindSafe for fuse_lowlevel_ops
Blanket Implementations
impl<T> Any for T where
T: 'static + ?Sized, [src]
T: 'static + ?Sized,
impl<T> Borrow<T> for T where
T: ?Sized, [src]
T: ?Sized,
impl<T> BorrowMut<T> for T where
T: ?Sized, [src]
T: ?Sized,
fn borrow_mut(&mut self) -> &mut T[src]
impl<T> From<T> for T[src]
impl<T, U> Into<U> for T where
U: From<T>, [src]
U: From<T>,
impl<T> ToOwned for T where
T: Clone, [src]
T: Clone,
type Owned = T
The resulting type after obtaining ownership.
fn to_owned(&self) -> T[src]
fn clone_into(&self, target: &mut T)[src]
impl<T, U> TryFrom<U> for T where
U: Into<T>, [src]
U: Into<T>,
type Error = Infallible
The type returned in the event of a conversion error.
fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>[src]
impl<T, U> TryInto<U> for T where
U: TryFrom<T>, [src]
U: TryFrom<T>,