Trait fuse_backend_rs::api::filesystem::AsyncFileSystem

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pub trait AsyncFileSystem: FileSystem {
    // Required methods
    fn async_lookup<'life0, 'life1, 'life2, 'async_trait>(
        &'life0 self,
        ctx: &'life1 Context,
        parent: Self::Inode,
        name: &'life2 CStr
    ) -> Pin<Box<dyn Future<Output = Result<Entry>> + Send + 'async_trait>>
       where Self: 'async_trait,
             'life0: 'async_trait,
             'life1: 'async_trait,
             'life2: 'async_trait;
    fn async_getattr<'life0, 'life1, 'async_trait>(
        &'life0 self,
        ctx: &'life1 Context,
        inode: Self::Inode,
        handle: Option<Self::Handle>
    ) -> Pin<Box<dyn Future<Output = Result<(stat64, Duration)>> + Send + 'async_trait>>
       where Self: 'async_trait,
             'life0: 'async_trait,
             'life1: 'async_trait;
    fn async_setattr<'life0, 'life1, 'async_trait>(
        &'life0 self,
        ctx: &'life1 Context,
        inode: Self::Inode,
        attr: stat64,
        handle: Option<Self::Handle>,
        valid: SetattrValid
    ) -> Pin<Box<dyn Future<Output = Result<(stat64, Duration)>> + Send + 'async_trait>>
       where Self: 'async_trait,
             'life0: 'async_trait,
             'life1: 'async_trait;
    fn async_open<'life0, 'life1, 'async_trait>(
        &'life0 self,
        ctx: &'life1 Context,
        inode: Self::Inode,
        flags: u32,
        fuse_flags: u32
    ) -> Pin<Box<dyn Future<Output = Result<(Option<Self::Handle>, OpenOptions)>> + Send + 'async_trait>>
       where Self: 'async_trait,
             'life0: 'async_trait,
             'life1: 'async_trait;
    fn async_create<'life0, 'life1, 'life2, 'async_trait>(
        &'life0 self,
        ctx: &'life1 Context,
        parent: Self::Inode,
        name: &'life2 CStr,
        args: CreateIn
    ) -> Pin<Box<dyn Future<Output = Result<(Entry, Option<Self::Handle>, OpenOptions)>> + Send + 'async_trait>>
       where Self: 'async_trait,
             'life0: 'async_trait,
             'life1: 'async_trait,
             'life2: 'async_trait;
    fn async_read<'life0, 'life1, 'life2, 'async_trait>(
        &'life0 self,
        ctx: &'life1 Context,
        inode: Self::Inode,
        handle: Self::Handle,
        w: &'life2 mut (dyn AsyncZeroCopyWriter + Send),
        size: u32,
        offset: u64,
        lock_owner: Option<u64>,
        flags: u32
    ) -> Pin<Box<dyn Future<Output = Result<usize>> + Send + 'async_trait>>
       where Self: 'async_trait,
             'life0: 'async_trait,
             'life1: 'async_trait,
             'life2: 'async_trait;
    fn async_write<'life0, 'life1, 'life2, 'async_trait>(
        &'life0 self,
        ctx: &'life1 Context,
        inode: Self::Inode,
        handle: Self::Handle,
        r: &'life2 mut (dyn AsyncZeroCopyReader + Send),
        size: u32,
        offset: u64,
        lock_owner: Option<u64>,
        delayed_write: bool,
        flags: u32,
        fuse_flags: u32
    ) -> Pin<Box<dyn Future<Output = Result<usize>> + Send + 'async_trait>>
       where Self: 'async_trait,
             'life0: 'async_trait,
             'life1: 'async_trait,
             'life2: 'async_trait;
    fn async_fsync<'life0, 'life1, 'async_trait>(
        &'life0 self,
        ctx: &'life1 Context,
        inode: Self::Inode,
        datasync: bool,
        handle: Self::Handle
    ) -> Pin<Box<dyn Future<Output = Result<()>> + Send + 'async_trait>>
       where Self: 'async_trait,
             'life0: 'async_trait,
             'life1: 'async_trait;
    fn async_fallocate<'life0, 'life1, 'async_trait>(
        &'life0 self,
        ctx: &'life1 Context,
        inode: Self::Inode,
        handle: Self::Handle,
        mode: u32,
        offset: u64,
        length: u64
    ) -> Pin<Box<dyn Future<Output = Result<()>> + Send + 'async_trait>>
       where Self: 'async_trait,
             'life0: 'async_trait,
             'life1: 'async_trait;
    fn async_fsyncdir<'life0, 'life1, 'async_trait>(
        &'life0 self,
        ctx: &'life1 Context,
        inode: Self::Inode,
        datasync: bool,
        handle: Self::Handle
    ) -> Pin<Box<dyn Future<Output = Result<()>> + Send + 'async_trait>>
       where Self: 'async_trait,
             'life0: 'async_trait,
             'life1: 'async_trait;
}
Expand description

The main trait that connects a file system with a transport with asynchronous IO.

Required Methods§

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fn async_lookup<'life0, 'life1, 'life2, 'async_trait>( &'life0 self, ctx: &'life1 Context, parent: Self::Inode, name: &'life2 CStr ) -> Pin<Box<dyn Future<Output = Result<Entry>> + Send + 'async_trait>>where Self: 'async_trait, 'life0: 'async_trait, 'life1: 'async_trait, 'life2: 'async_trait,

Look up a directory entry by name and get its attributes.

If this call is successful then the lookup count of the Inode associated with the returned Entry must be increased by 1.

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fn async_getattr<'life0, 'life1, 'async_trait>( &'life0 self, ctx: &'life1 Context, inode: Self::Inode, handle: Option<Self::Handle> ) -> Pin<Box<dyn Future<Output = Result<(stat64, Duration)>> + Send + 'async_trait>>where Self: 'async_trait, 'life0: 'async_trait, 'life1: 'async_trait,

Get attributes for a file / directory.

If handle is not None, then it contains the handle previously returned by the implementation after a call to open or opendir. However, implementations should still take care to verify the handle if they do not trust the client (e.g., virtio-fs).

If writeback caching is enabled (FsOptions::WRITEBACK_CACHE), then the kernel module likely has a better idea of the length of the file than the file system (for example, if there was a write that extended the size of the file but has not yet been flushed). In this case, the st_size field of the returned struct is ignored.

The returned Duration indicates how long the returned attributes should be considered valid by the client. If the attributes are only changed via the FUSE kernel module (i.e., the kernel module has exclusive access), then this should be a very large value.

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fn async_setattr<'life0, 'life1, 'async_trait>( &'life0 self, ctx: &'life1 Context, inode: Self::Inode, attr: stat64, handle: Option<Self::Handle>, valid: SetattrValid ) -> Pin<Box<dyn Future<Output = Result<(stat64, Duration)>> + Send + 'async_trait>>where Self: 'async_trait, 'life0: 'async_trait, 'life1: 'async_trait,

Set attributes for a file / directory.

If handle is not None, then it contains the handle previously returned by the implementation after a call to open or opendir. However, implementations should still take care to verify the handle if they do not trust the client (e.g., virtio-fs).

The valid parameter indicates the fields of attr that may be considered valid and should be set by the file system. The content of all other fields in attr is undefined.

If the FsOptions::HANDLE_KILLPRIV was set during init, then the implementation is expected to reset the setuid and setgid bits if the file size or owner is being changed.

This method returns the new attributes after making the modifications requested by the client. The returned Duration indicates how long the returned attributes should be considered valid by the client. If the attributes are only changed via the FUSE kernel module (i.e., the kernel module has exclusive access), then this should be a very large value.

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fn async_open<'life0, 'life1, 'async_trait>( &'life0 self, ctx: &'life1 Context, inode: Self::Inode, flags: u32, fuse_flags: u32 ) -> Pin<Box<dyn Future<Output = Result<(Option<Self::Handle>, OpenOptions)>> + Send + 'async_trait>>where Self: 'async_trait, 'life0: 'async_trait, 'life1: 'async_trait,

Open a file.

Open the file associated with inode for reading / writing. All values accepted by the open(2) system call are valid values for flags and must be handled by the file system. However, there are some additional rules:

  • Creation flags (libc::O_CREAT, libc::O_EXCL, libc::O_NOCTTY) will be filtered out and handled by the kernel.

  • The file system should check the access modes (libc::O_RDONLY, libc::O_WRONLY, libc::O_RDWR) to determine if the operation is permitted. If the file system was mounted with the -o default_permissions mount option, then this check will also be carried out by the kernel before sending the open request.

  • When writeback caching is enabled (FsOptions::WRITEBACK_CACHE) the kernel may send read requests even for files opened with libc::O_WRONLY. The file system should be prepared to handle this.

  • When writeback caching is enabled, the kernel will handle the libc::O_APPEND flag. However, this will not work reliably unless the kernel has exclusive access to the file. In this case the file system may either ignore the libc::O_APPEND flag or return an error to indicate that reliable libc::O_APPEND handling is not available.

  • When writeback caching is disabled, the file system is expected to properly handle libc::O_APPEND and ensure that each write is appended to the end of the file.

The file system may choose to return a Handle to refer to the newly opened file. The kernel will then use this Handle for all operations on the content of the file (read, write, flush, release, fsync). If the file system does not return a Handle then the kernel will use the Inode for the file to operate on its contents. In this case the file system may wish to enable the FsOptions::ZERO_MESSAGE_OPEN feature if it is supported by the kernel (see below).

The returned OpenOptions allow the file system to change the way the opened file is handled by the kernel. See the documentation of OpenOptions for more information.

If the FsOptions::ZERO_MESSAGE_OPEN feature is enabled by both the file system implementation and the kernel, then the file system may return an error of ENOSYS. This will be interpreted by the kernel as success and future calls to open and release will be handled by the kernel without being passed on to the file system.

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fn async_create<'life0, 'life1, 'life2, 'async_trait>( &'life0 self, ctx: &'life1 Context, parent: Self::Inode, name: &'life2 CStr, args: CreateIn ) -> Pin<Box<dyn Future<Output = Result<(Entry, Option<Self::Handle>, OpenOptions)>> + Send + 'async_trait>>where Self: 'async_trait, 'life0: 'async_trait, 'life1: 'async_trait, 'life2: 'async_trait,

Create and open a file.

If the file does not already exist, the file system should create it with the specified mode. When the FsOptions::DONT_MASK feature is set, the file system is responsible for setting the permissions of the created file to mode & !umask.

If the file system returns an ENOSYS error, then the kernel will treat this method as unimplemented and all future calls to create will be handled by calling the mknod and open methods instead.

See the documentation for the open method for more information about opening the file. In addition to the optional Handle and the OpenOptions, the file system must also return an Entry for the file. This increases the lookup count for the Inode associated with the file by 1.

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fn async_read<'life0, 'life1, 'life2, 'async_trait>( &'life0 self, ctx: &'life1 Context, inode: Self::Inode, handle: Self::Handle, w: &'life2 mut (dyn AsyncZeroCopyWriter + Send), size: u32, offset: u64, lock_owner: Option<u64>, flags: u32 ) -> Pin<Box<dyn Future<Output = Result<usize>> + Send + 'async_trait>>where Self: 'async_trait, 'life0: 'async_trait, 'life1: 'async_trait, 'life2: 'async_trait,

Read data from a file.

Returns size bytes of data starting from offset off from the file associated with inode or handle.

flags contains the flags used to open the file. Similarly, handle is the Handle returned by the file system from the open method, if any. If the file system implementation did not return a Handle from open then the contents of handle are undefined.

This method should return exactly the number of bytes requested by the kernel, except in the case of error or EOF. Otherwise, the kernel will substitute the rest of the data with zeroes. An exception to this rule is if the file was opened with the “direct I/O” option (libc::O_DIRECT), in which case the kernel will forward the return code from this method to the userspace application that made the system call.

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fn async_write<'life0, 'life1, 'life2, 'async_trait>( &'life0 self, ctx: &'life1 Context, inode: Self::Inode, handle: Self::Handle, r: &'life2 mut (dyn AsyncZeroCopyReader + Send), size: u32, offset: u64, lock_owner: Option<u64>, delayed_write: bool, flags: u32, fuse_flags: u32 ) -> Pin<Box<dyn Future<Output = Result<usize>> + Send + 'async_trait>>where Self: 'async_trait, 'life0: 'async_trait, 'life1: 'async_trait, 'life2: 'async_trait,

Write data to a file.

Writes size bytes of data starting from offset off to the file associated with inode or handle.

flags contains the flags used to open the file. Similarly, handle is the Handle returned by the file system from the open method, if any. If the file system implementation did not return a Handle from open then the contents of handle are undefined.

If the FsOptions::HANDLE_KILLPRIV feature is not enabled then then the file system is expected to clear the setuid and setgid bits.

If delayed_write is true then it indicates that this is a write for buffered data.

This method should return exactly the number of bytes requested by the kernel, except in the case of error. An exception to this rule is if the file was opened with the “direct I/O” option (libc::O_DIRECT), in which case the kernel will forward the return code from this method to the userspace application that made the system call.

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fn async_fsync<'life0, 'life1, 'async_trait>( &'life0 self, ctx: &'life1 Context, inode: Self::Inode, datasync: bool, handle: Self::Handle ) -> Pin<Box<dyn Future<Output = Result<()>> + Send + 'async_trait>>where Self: 'async_trait, 'life0: 'async_trait, 'life1: 'async_trait,

Synchronize file contents.

File systems must ensure that the file contents have been flushed to disk before returning from this method. If datasync is true then only the file data (but not the metadata) needs to be flushed.

handle is the Handle returned by the file system from the open method, if any. If the file system did not return a Handle from open then the contents of handle are undefined.

If this method returns an ENOSYS error then the kernel will treat it as success and all subsequent calls to fsync will be handled by the kernel without being forwarded to the file system.

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fn async_fallocate<'life0, 'life1, 'async_trait>( &'life0 self, ctx: &'life1 Context, inode: Self::Inode, handle: Self::Handle, mode: u32, offset: u64, length: u64 ) -> Pin<Box<dyn Future<Output = Result<()>> + Send + 'async_trait>>where Self: 'async_trait, 'life0: 'async_trait, 'life1: 'async_trait,

Allocate requested space for file data.

If this function returns success, then the file sytem must guarantee that it is possible to write up to length bytes of data starting at offset without failing due to a lack of free space on the disk.

handle is the Handle returned by the file system from the open method, if any. If the file system did not return a Handle from open then the contents of handle are undefined.

If this method returns an ENOSYS error then the kernel will treat that as a permanent failure: all future calls to fallocate will fail with EOPNOTSUPP without being forwarded to the file system.

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fn async_fsyncdir<'life0, 'life1, 'async_trait>( &'life0 self, ctx: &'life1 Context, inode: Self::Inode, datasync: bool, handle: Self::Handle ) -> Pin<Box<dyn Future<Output = Result<()>> + Send + 'async_trait>>where Self: 'async_trait, 'life0: 'async_trait, 'life1: 'async_trait,

Synchronize the contents of a directory.

File systems must ensure that the directory contents have been flushed to disk before returning from this method. If datasync is true then only the directory data (but not the metadata) needs to be flushed.

handle is the Handle returned by the file system from the opendir method, if any. If the file system did not return a Handle from opendir then the contents of handle are undefined.

If this method returns an ENOSYS error then the kernel will treat it as success and all subsequent calls to fsyncdir will be handled by the kernel without being forwarded to the file system.

Implementations on Foreign Types§

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impl<FS: AsyncFileSystem> AsyncFileSystem for Arc<FS>

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fn async_lookup<'a, 'b, 'c, 'async_trait>( &'a self, ctx: &'b Context, parent: Self::Inode, name: &'c CStr ) -> Pin<Box<dyn Future<Output = Result<Entry>> + Send + 'async_trait>>where Self: 'async_trait, 'a: 'async_trait, 'b: 'async_trait, 'c: 'async_trait,

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fn async_getattr<'a, 'b, 'async_trait>( &'a self, ctx: &'b Context, inode: Self::Inode, handle: Option<Self::Handle> ) -> Pin<Box<dyn Future<Output = Result<(stat64, Duration)>> + Send + 'async_trait>>where Self: 'async_trait, 'a: 'async_trait, 'b: 'async_trait,

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fn async_setattr<'a, 'b, 'async_trait>( &'a self, ctx: &'b Context, inode: Self::Inode, attr: stat64, handle: Option<Self::Handle>, valid: SetattrValid ) -> Pin<Box<dyn Future<Output = Result<(stat64, Duration)>> + Send + 'async_trait>>where Self: 'async_trait, 'a: 'async_trait, 'b: 'async_trait,

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fn async_open<'a, 'b, 'async_trait>( &'a self, ctx: &'b Context, inode: Self::Inode, flags: u32, fuse_flags: u32 ) -> Pin<Box<dyn Future<Output = Result<(Option<Self::Handle>, OpenOptions)>> + Send + 'async_trait>>where Self: 'async_trait, 'a: 'async_trait, 'b: 'async_trait,

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fn async_create<'a, 'b, 'c, 'async_trait>( &'a self, ctx: &'b Context, parent: Self::Inode, name: &'c CStr, args: CreateIn ) -> Pin<Box<dyn Future<Output = Result<(Entry, Option<Self::Handle>, OpenOptions)>> + Send + 'async_trait>>where Self: 'async_trait, 'a: 'async_trait, 'b: 'async_trait, 'c: 'async_trait,

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fn async_read<'a, 'b, 'c, 'async_trait>( &'a self, ctx: &'b Context, inode: Self::Inode, handle: Self::Handle, w: &'c mut (dyn AsyncZeroCopyWriter + Send), size: u32, offset: u64, lock_owner: Option<u64>, flags: u32 ) -> Pin<Box<dyn Future<Output = Result<usize>> + Send + 'async_trait>>where Self: 'async_trait, 'a: 'async_trait, 'b: 'async_trait, 'c: 'async_trait,

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fn async_write<'a, 'b, 'c, 'async_trait>( &'a self, ctx: &'b Context, inode: Self::Inode, handle: Self::Handle, r: &'c mut (dyn AsyncZeroCopyReader + Send), size: u32, offset: u64, lock_owner: Option<u64>, delayed_write: bool, flags: u32, fuse_flags: u32 ) -> Pin<Box<dyn Future<Output = Result<usize>> + Send + 'async_trait>>where Self: 'async_trait, 'a: 'async_trait, 'b: 'async_trait, 'c: 'async_trait,

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fn async_fsync<'a, 'b, 'async_trait>( &'a self, ctx: &'b Context, inode: Self::Inode, datasync: bool, handle: Self::Handle ) -> Pin<Box<dyn Future<Output = Result<()>> + Send + 'async_trait>>where Self: 'async_trait, 'a: 'async_trait, 'b: 'async_trait,

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fn async_fallocate<'a, 'b, 'async_trait>( &'a self, ctx: &'b Context, inode: Self::Inode, handle: Self::Handle, mode: u32, offset: u64, length: u64 ) -> Pin<Box<dyn Future<Output = Result<()>> + Send + 'async_trait>>where Self: 'async_trait, 'a: 'async_trait, 'b: 'async_trait,

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fn async_fsyncdir<'a, 'b, 'async_trait>( &'a self, ctx: &'b Context, inode: Self::Inode, datasync: bool, handle: Self::Handle ) -> Pin<Box<dyn Future<Output = Result<()>> + Send + 'async_trait>>where Self: 'async_trait, 'a: 'async_trait, 'b: 'async_trait,

Implementors§