Add Buf::create_unlocked.

kernel-rs/src/bio.rs

@@ -160,6 +160,12 @@ impl Buf {
         unsafe { &mut *entry.inner.get_mut_raw() }
     }
 
+    /// Returns a `BufUnlocked` without releasing the lock or consuming `self`.
+    pub fn create_unlocked(&self) -> BufUnlocked {
+        unsafe { ManuallyDrop::take(&mut self.inner.clone()) }
+    }
+
+    /// Returns a `BufUnlocked` after releasing the lock and consuming `self`.
     pub fn unlock(mut self, ctx: &KernelCtx<'_, '_>) -> BufUnlocked {
         // SAFETY: this method consumes self and self.inner will not be used again.
         let inner = unsafe { ManuallyDrop::take(&mut self.inner) };
@@ -169,6 +175,7 @@ impl Buf {
         inner
     }
 
+    /// Releases the lock and consumes `self`.
     pub fn free(self, ctx: &KernelCtx<'_, '_>) {
         let _ = self.unlock(ctx);
     }

kernel-rs/src/fs/lfs/segment.rs

@@ -204,10 +204,9 @@ impl Segment {
             let mut buf = self.read_segment_block(self.offset + 1, ctx);
             buf.deref_inner_mut().data.fill(0);
             buf.deref_inner_mut().valid = true;
-            let buf = buf.unlock(ctx);
-            self.segment_summary[self.offset] = f(buf.clone());
+            self.segment_summary[self.offset] = f(buf.create_unlocked());
             self.offset += 1;
-            Some((buf.lock(ctx), self.get_disk_block_no(self.offset, ctx)))
+            Some((buf, self.get_disk_block_no(self.offset, ctx)))
         }
     }