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use std::{path::Path, os::unix::ffi::OsStrExt, ffi::CString};
use bch_bindgen::c::{bchfs_handle, BCH_IOCTL_SUBVOLUME_CREATE, BCH_IOCTL_SUBVOLUME_DESTROY, bch_ioctl_subvolume, bcache_fs_open, BCH_SUBVOL_SNAPSHOT_CREATE, bcache_fs_close};
use errno::Errno;
/// A handle to a bcachefs filesystem
/// This can be used to send [`libc::ioctl`] to the underlying filesystem.
pub(crate) struct BcachefsHandle {
inner: bchfs_handle
}
impl BcachefsHandle {
/// Opens a bcachefs filesystem and returns its handle
/// TODO(raitobezarius): how can this not be faillible?
pub(crate) unsafe fn open<P: AsRef<Path>>(path: P) -> Self {
let path = CString::new(path.as_ref().as_os_str().as_bytes()).expect("Failed to cast path into a C-style string");
Self {
inner: bcache_fs_open(path.as_ptr())
}
}
}
/// I/O control commands that can be sent to a bcachefs filesystem
/// Those are non-exhaustive
#[repr(u64)]
#[non_exhaustive]
pub enum BcachefsIoctl {
SubvolumeCreate = BCH_IOCTL_SUBVOLUME_CREATE,
SubvolumeDestroy = BCH_IOCTL_SUBVOLUME_DESTROY,
}
/// I/O control commands payloads
#[non_exhaustive]
pub enum BcachefsIoctlPayload {
Subvolume(bch_ioctl_subvolume),
}
impl From<&BcachefsIoctlPayload> for *const libc::c_void {
fn from(value: &BcachefsIoctlPayload) -> Self {
match value {
BcachefsIoctlPayload::Subvolume(p) => p as *const _ as *const libc::c_void
}
}
}
impl BcachefsHandle {
/// Type-safe [`libc::ioctl`] for bcachefs filesystems
pub fn ioctl(&self, request: BcachefsIoctl, payload: &BcachefsIoctlPayload) -> Result<(), Errno> {
let payload_ptr: *const libc::c_void = payload.into();
let ret = unsafe { libc::ioctl(self.inner.ioctl_fd, request as u64, payload_ptr) };
if ret == -1 {
Err(errno::errno())
} else {
Ok(())
}
}
/// Create a subvolume for this bcachefs filesystem
/// at the given path
pub fn create_subvolume<P: AsRef<Path>>(&self, dst: P) -> Result<(), Errno> {
let dst = CString::new(dst.as_ref().as_os_str().as_bytes()).expect("Failed to cast destination path for subvolume in a C-style string");
self.ioctl(BcachefsIoctl::SubvolumeCreate, &BcachefsIoctlPayload::Subvolume(bch_ioctl_subvolume {
dirfd: libc::AT_FDCWD,
mode: 0o777,
dst_ptr: dst.as_ptr() as u64,
..Default::default()
}))
}
/// Delete the subvolume at the given path
/// for this bcachefs filesystem
pub fn delete_subvolume<P: AsRef<Path>>(&self, dst: P) -> Result<(), Errno> {
let dst = CString::new(dst.as_ref().as_os_str().as_bytes()).expect("Failed to cast destination path for subvolume in a C-style string");
self.ioctl(BcachefsIoctl::SubvolumeDestroy, &BcachefsIoctlPayload::Subvolume(bch_ioctl_subvolume {
dirfd: libc::AT_FDCWD,
mode: 0o777,
dst_ptr: dst.as_ptr() as u64,
..Default::default()
}))
}
/// Snapshot a subvolume for this bcachefs filesystem
/// at the given path
pub fn snapshot_subvolume<P: AsRef<Path>>(&self, extra_flags: u32, src: P, dst: P) -> Result<(), Errno> {
let src = CString::new(src.as_ref().as_os_str().as_bytes()).expect("Failed to cast source path for subvolume in a C-style string");
let dst = CString::new(dst.as_ref().as_os_str().as_bytes()).expect("Failed to cast destination path for subvolume in a C-style string");
self.ioctl(BcachefsIoctl::SubvolumeCreate, &BcachefsIoctlPayload::Subvolume(bch_ioctl_subvolume {
flags: BCH_SUBVOL_SNAPSHOT_CREATE | extra_flags,
dirfd: libc::AT_FDCWD,
mode: 0o777,
src_ptr: src.as_ptr() as u64,
dst_ptr: dst.as_ptr() as u64,
..Default::default()
}))
}
}
impl Drop for BcachefsHandle {
fn drop(&mut self) {
unsafe { bcache_fs_close(self.inner) };
}
}
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