From f13f756c206b8c6457bb2ff018e33cd1a73bf691 Mon Sep 17 00:00:00 2001
From: Mark Poliakov <mark@alnyan.me>
Date: Thu, 2 Jan 2025 17:20:24 +0200
Subject: [PATCH] ext2: dedup block/inode free code

---
 kernel/driver/fs/ext2/src/allocation.rs | 94 +++++++++++++------------
 1 file changed, 50 insertions(+), 44 deletions(-)

diff --git a/kernel/driver/fs/ext2/src/allocation.rs b/kernel/driver/fs/ext2/src/allocation.rs
index eb949228..d1c4846b 100644
--- a/kernel/driver/fs/ext2/src/allocation.rs
+++ b/kernel/driver/fs/ext2/src/allocation.rs
@@ -4,9 +4,38 @@ use yggdrasil_abi::io::FileType;
 use crate::{BlockGroupDescriptor, Ext2Fs, ExtendedSuperblock, Inode};
 
 impl Ext2Fs {
+    async fn free<
+        F: FnOnce(&mut BlockGroupDescriptor) -> u32,
+        G: FnOnce(&mut ExtendedSuperblock),
+    >(
+        &self,
+        element_index: u32,
+        group_index: u32,
+        descriptor_mapper: F,
+        superblock_mapper: G,
+    ) -> Result<(), Error> {
+        let bitmap = self
+            .with_bgdt_entry_mut(group_index, |descriptor| Ok(descriptor_mapper(descriptor)))
+            .await?;
+        self.with_block_mut(bitmap, size_of::<u32>(), |bitmap| {
+            let index = (element_index / 8) as usize;
+            let bit = 1u8 << (element_index % 8);
+
+            if bitmap[index] & bit == 0 {
+                log::warn!("Trying to free an unallocated element #{element_index}");
+            }
+            bitmap[index] &= !bit;
+            Ok(())
+        })
+        .await?;
+        self.with_superblock_mut(|sb| Ok(superblock_mapper(sb)))
+            .await?;
+        Ok(())
+    }
+
     async fn allocate<
         F: Fn(&mut BlockGroupDescriptor) -> Option<(u32, u32)>,
-        G: Fn(&mut ExtendedSuperblock),
+        G: FnOnce(&mut ExtendedSuperblock),
     >(
         &self,
         descriptor_mapper: F,
@@ -95,38 +124,26 @@ impl Ext2Fs {
 
         // Free inode blocks
         inode.resize(self, 0).await?;
-
         inode.dtime = real_time().seconds as u32;
 
         self.write_inode(ino, inode).await?;
 
         let inode_index = ino - 1;
         let group_index = inode_index / self.block_group_inode_count;
-
-        let bitmap = self
-            .with_bgdt_entry_mut(group_index, |descriptor| {
+        self.free(
+            inode_index,
+            group_index,
+            |descriptor| {
                 if is_directory {
                     descriptor.directories = descriptor.directories.saturating_sub(1);
                 }
                 descriptor.unallocated_inodes += 1;
-                Ok(descriptor.inode_usage_bitmap)
-            })
-            .await?;
-        self.with_block_mut(bitmap, size_of::<u32>(), |bitmap| {
-            let index = (inode_index / 8) as usize;
-            let bit = 1u8 << (inode_index % 8);
-
-            if bitmap[index] & bit == 0 {
-                log::warn!("Trying to free an unallocated inode #{ino}");
-            }
-            bitmap[index] &= !bit;
-            Ok(())
-        })
-        .await?;
-        self.with_superblock_mut(|sb| {
-            sb.total_unallocated_inodes += 1;
-            Ok(())
-        })
+                descriptor.inode_usage_bitmap
+            },
+            |superblock| {
+                superblock.total_unallocated_inodes += 1;
+            },
+        )
         .await?;
 
         Ok(())
@@ -161,28 +178,17 @@ impl Ext2Fs {
         }
 
         let group_index = block_index / self.block_group_block_count;
-        let bitmap = self
-            .with_bgdt_entry_mut(group_index, |descriptor| {
+        self.free(
+            block_index,
+            group_index,
+            |descriptor| {
                 descriptor.unallocated_blocks += 1;
-                Ok(descriptor.block_usage_bitmap)
-            })
-            .await?;
-        self.with_block_mut(bitmap, size_of::<u32>(), |bitmap| {
-            let index = (block_index / 8) as usize;
-            let bit = 1u8 << (block_index % 8);
-
-            if bitmap[index] & bit == 0 {
-                log::warn!("Freeing a block #{block_index}, but bitmap says it's not allocated");
-            }
-            bitmap[index] &= !bit;
-
-            Ok(())
-        })
-        .await?;
-        self.with_superblock_mut(|sb| {
-            sb.total_unallocated_blocks += 1;
-            Ok(())
-        })
+                descriptor.block_usage_bitmap
+            },
+            |superblock| {
+                superblock.total_unallocated_blocks += 1;
+            },
+        )
         .await?;
 
         Ok(())