From b5f23b00cd670f8817c97825ea200ec344b39414 Mon Sep 17 00:00:00 2001
From: beviu <contact@beviu.com>
Date: Sat, 20 Sep 2025 22:15:01 +0200
Subject: [PATCH] Use bcache_fs_open_fallible in BcachefsHandle::open

Also, as long as the path is valid, bcache_fs_open{,fallible} do not
do anything unsafe so BcachefsHandle::open does not need to be marked
unsafe.
---
 bch_bindgen/build.rs      |  2 +-
 src/commands/subvolume.rs |  8 +++++---
 src/wrappers/handle.rs    | 20 ++++++++++----------
 3 files changed, 16 insertions(+), 14 deletions(-)

diff --git a/bch_bindgen/build.rs b/bch_bindgen/build.rs
index 10d5e575..c923f954 100644
--- a/bch_bindgen/build.rs
+++ b/bch_bindgen/build.rs
@@ -53,7 +53,7 @@ fn main() {
         .allowlist_function("cmd_.*")
         .allowlist_function(".*_cmds")
         .allowlist_function(".*bch2_.*")
-        .allowlist_function("bcache_fs_open")
+        .allowlist_function("bcache_fs_open_fallible")
         .allowlist_function("bcache_fs_close")
         .allowlist_function("bio_.*")
         .allowlist_function("derive_passphrase")
diff --git a/src/commands/subvolume.rs b/src/commands/subvolume.rs
index 6f5f2f2b..fb94ea8f 100644
--- a/src/commands/subvolume.rs
+++ b/src/commands/subvolume.rs
@@ -54,7 +54,8 @@ pub fn subvolume(argv: Vec<String>) -> Result<()> {
                 };
 
                 if let Some(dirname) = target.parent() {
-                    let fs = unsafe { BcachefsHandle::open(dirname) };
+                    let fs =
+                        BcachefsHandle::open(dirname).context("Failed to open the filesystem")?;
                     fs.create_subvolume(target)
                         .context("Failed to create the subvolume")?;
                 }
@@ -67,7 +68,8 @@ pub fn subvolume(argv: Vec<String>) -> Result<()> {
                     .context("subvolume path does not exist or can not be canonicalized")?;
 
                 if let Some(dirname) = target.parent() {
-                    let fs = unsafe { BcachefsHandle::open(dirname) };
+                    let fs =
+                        BcachefsHandle::open(dirname).context("Failed to open the filesystem")?;
                     fs.delete_subvolume(target)
                         .context("Failed to delete the subvolume")?;
                 }
@@ -85,7 +87,7 @@ pub fn subvolume(argv: Vec<String>) -> Result<()> {
                 } else {
                     dirname
                 };
-                let fs = unsafe { BcachefsHandle::open(dir) };
+                let fs = BcachefsHandle::open(dir).context("Failed to open the filesystem")?;
 
                 fs.snapshot_subvolume(
                     if read_only {
diff --git a/src/wrappers/handle.rs b/src/wrappers/handle.rs
index a94f7305..f85637d0 100644
--- a/src/wrappers/handle.rs
+++ b/src/wrappers/handle.rs
@@ -1,13 +1,13 @@
+use std::mem::MaybeUninit;
 use std::path::Path;
 
 use bch_bindgen::c::{
-    bcache_fs_close, bcache_fs_open, bch_ioctl_subvolume, bch_ioctl_subvolume_v2, bch_ioctl_err_msg, bchfs_handle,
-    BCH_IOCTL_SUBVOLUME_CREATE,
-    BCH_IOCTL_SUBVOLUME_CREATE_v2,
-    BCH_IOCTL_SUBVOLUME_DESTROY,
-    BCH_IOCTL_SUBVOLUME_DESTROY_v2,
+    bcache_fs_close, bcache_fs_open_fallible, bch_errcode, bch_ioctl_err_msg, bch_ioctl_subvolume,
+    bch_ioctl_subvolume_v2, bchfs_handle, BCH_IOCTL_SUBVOLUME_CREATE_v2,
+    BCH_IOCTL_SUBVOLUME_DESTROY_v2, BCH_IOCTL_SUBVOLUME_CREATE, BCH_IOCTL_SUBVOLUME_DESTROY,
     BCH_SUBVOL_SNAPSHOT_CREATE,
 };
+use bch_bindgen::errcode::ret_to_result;
 use bch_bindgen::path_to_cstr;
 use errno::Errno;
 
@@ -19,12 +19,12 @@ pub(crate) struct BcachefsHandle {
 
 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 {
+    pub(crate) fn open<P: AsRef<Path>>(path: P) -> Result<Self, bch_errcode> {
         let path = path_to_cstr(path);
-        Self {
-            inner: bcache_fs_open(path.as_ptr()),
-        }
+        let mut handle: MaybeUninit<bchfs_handle> = MaybeUninit::uninit();
+        ret_to_result(unsafe { bcache_fs_open_fallible(path.as_ptr(), handle.as_mut_ptr()) })?;
+        let inner = unsafe { handle.assume_init() };
+        Ok(Self { inner })
     }
 }