From 1ef396b684a419b5a50ab215103486d189068800 Mon Sep 17 00:00:00 2001
From: Kent Overstreet <kent.overstreet@linux.dev>
Date: Mon, 5 Feb 2024 20:33:10 -0500
Subject: [PATCH] cmd_subvolume: Fix snapshot creation with implicit source

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
---
 src/commands/cmd_subvolume.rs |  3 ++-
 src/wrappers/handle.rs        | 16 +++++++++++-----
 2 files changed, 13 insertions(+), 6 deletions(-)

diff --git a/src/commands/cmd_subvolume.rs b/src/commands/cmd_subvolume.rs
index 57c679a..85183fa 100644
--- a/src/commands/cmd_subvolume.rs
+++ b/src/commands/cmd_subvolume.rs
@@ -22,11 +22,12 @@ enum Subcommands {
         /// Path
         target: PathBuf
     },
+    #[command(allow_missing_positional = true)]
     Snapshot {
         /// Make snapshot read only
         #[arg(long, short = 'r')]
         read_only: bool,
-        source: PathBuf,
+        source: Option<PathBuf>,
         dest: PathBuf
     }
 }
diff --git a/src/wrappers/handle.rs b/src/wrappers/handle.rs
index 9dd6618..336a029 100644
--- a/src/wrappers/handle.rs
+++ b/src/wrappers/handle.rs
@@ -82,17 +82,23 @@ impl BcachefsHandle {
 
     /// 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");
+    pub fn snapshot_subvolume<P: AsRef<Path>>(&self, extra_flags: u32, src: Option<P>, dst: P) -> Result<(), Errno> {
+        let src = src.map(|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 {
+
+        let res = 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,
+            src_ptr: src.as_ref().map_or(0, |x| x.as_ptr() as u64),
+            //src_ptr: if let Some(src) = src { src.as_ptr() } else { std::ptr::null() } as u64,
             dst_ptr: dst.as_ptr() as u64,
             ..Default::default()
-        }))
+        }));
+
+        drop(src);
+        drop(dst);
+        res
     }
 }
 
-- 
2.39.5