Add dir entry operations

2 files changed, 179 insertions, 30 deletions

diff --git a/src/disk/allocation.rs b/src/disk/allocation.rs
index bde2014..57cca0e 100644
--- a/src/disk/allocation.rs
+++ b/src/disk/allocation.rs
@@ -1,20 +1,20 @@
-use crate::disk::block::{DataBlock, DoubleIndirectBlock, IndirectBlock, TripleIndirectBlock};
-use crate::disk::inode::Inode;
-use crate::memory::cached_block::convert;
-use crate::AyaFS;
+use crate::disk::block::{Block, DataBlock, DoubleIndirectBlock, IndirectBlock, TripleIndirectBlock};
+use crate::disk::inode::{DIRECT_NUMBER, Inode};
+use crate::memory::cached_block::{CachedBlock, convert};
+use crate::{AyaFS, INODE_PER_BLOCK};
 
 impl AyaFS {
-    /// 为 Inode 分配新 block, 返回 block 的编号
-    pub(crate) fn allocate_block_for(&mut self, inode: &mut Inode) -> Option<u32> {
+    /// 为 Inode 分配新 block, 返回 block 的编号和它在 inode 内的编号
+    pub(crate) fn allocate_block_for(&mut self, inode: &mut Inode) -> Option<(u32, usize)> {
         // 先看这个 inode 的 direct block 有没有空闲
-        for index in inode.direct.iter_mut() {
+        for (index_within_direct, index) in inode.direct.iter_mut().enumerate() {
             if !self.data_bitmap.query(*index as usize) {
                 let block_index = self.data_bitmap.allocate().unwrap() as u32;
                 // println!("allocating {} for direct", block_index);
                 *index = block_index;
                 inode.n_blocks += 1;
                 // 当调用 get_inode_mut 拿出 &mut Inode 的时候对应的 block 在 cache 里已经脏了
-                return Some(block_index);
+                return Some((block_index, index_within_direct));
             }
         }
 
@@ -27,10 +27,11 @@ impl AyaFS {
             // println!("allocating {} for indirect", inode.single_indirect);
         }
         // 在 indirect block 里尝试分配
-        if let Some(block_index) = self.allocate_in_indirect(inode.single_indirect) {
+        if let Some((block_index, index_within_indirect)) = self.allocate_in_indirect(inode.single_indirect) {
             // println!("allocating {} in indirect", block_index);
             inode.n_blocks += 1;
-            return Some(block_index);
+            let index_within_block = DIRECT_NUMBER + index_within_indirect;
+            return Some((block_index, index_within_block));
         }
 
         // direct & indirect block 全部分配完了, 先检查 double indirect block 有没有分配, 没有就分配一个
@@ -42,10 +43,11 @@ impl AyaFS {
             // println!("allocating {} for double indirect", inode.double_indirect);
         }
         // 在 double indirect block 里尝试分配
-        if let Some(block_index) = self.alloc_in_double_indirect(inode.double_indirect) {
+        if let Some((block_index, index_within_double)) = self.alloc_in_double_indirect(inode.double_indirect) {
             // println!("allocating {} in double indirect", block_index);
             inode.n_blocks += 1;
-            return Some(block_index);
+            let index_within_block = DIRECT_NUMBER + INODE_PER_BLOCK + index_within_double;
+            return Some((block_index, index_within_block));
         }
 
         // direct, indirect & double indirect block 全部分配完了, 先检查 triple indirect block 有没有分配, 没有就分配一个
@@ -57,15 +59,16 @@ impl AyaFS {
             // println!("allocating {} for triple indirect", inode.triple_indirect);
         }
         // 在 double indirect block 里尝试分配
-        if let Some(block_index) = self.alloc_in_triple_indirect(inode.triple_indirect) {
+        if let Some((block_index, index_within_triple)) = self.alloc_in_triple_indirect(inode.triple_indirect) {
             // println!("allocating {} in triple indirect", block_index);
             inode.n_blocks += 1;
-            return Some(block_index);
+            let index_within_block = DIRECT_NUMBER + INODE_PER_BLOCK + INODE_PER_BLOCK * INODE_PER_BLOCK + index_within_triple;
+            return Some((block_index, index_within_block));
         }
         None
     }
 
-    fn allocate_in_indirect(&mut self, indirect_entry: u32) -> Option<u32> {
+    fn allocate_in_indirect(&mut self, indirect_entry: u32) -> Option<(u32, usize)> {
         // 取出 single indirect block, 尝试在里面分配
         let indirect_entry = indirect_entry as usize;
         // println!("finding indirect block with number {}, bitmap says {}", indirect_entry, self.data_bitmap.query(indirect_entry));
@@ -76,20 +79,20 @@ impl AyaFS {
         {
             // println!("found indirect block with number {}", indirect_entry);
             let mut indirect_block = block.clone();
-            for entry in indirect_block.block.entries.iter_mut() {
+            for (index_within_indirect, entry) in indirect_block.block.entries.iter_mut().enumerate() {
                 if self.data_bitmap.query(*entry as usize) == false {
                     indirect_block.dirty = true; // 把这个块标记为 dirty
                     let block_index = self.data_bitmap.allocate().expect("No free space") as u32;
                     *entry = block_index;
                     self.update_block(indirect_block);
-                    return Some(block_index);
+                    return Some((block_index, index_within_indirect));
                 }
             }
         }
         None
     }
 
-    fn alloc_in_double_indirect(&mut self, double_indirect_entry: u32) -> Option<u32> {
+    fn alloc_in_double_indirect(&mut self, double_indirect_entry: u32) -> Option<(u32, usize)> {
         let double_indirect_entry = double_indirect_entry as usize;
 
         if let Some(block) = self
@@ -97,24 +100,27 @@ impl AyaFS {
             .map(convert::<DataBlock, DoubleIndirectBlock>)
         {
             let mut double_indirect_block = block.clone();
-            for indirect_entry in double_indirect_block.block.indirect.iter_mut() {
+            let mut double_indirect_modified = false;
+            for (index_within_double_indirect, indirect_entry) in double_indirect_block.block.indirect.iter_mut().enumerate() {
                 if self.data_bitmap.query(*indirect_entry as usize) == false {
                     double_indirect_block.dirty = true;
+                    double_indirect_modified = true;
                     *indirect_entry = self.data_bitmap.allocate().expect("No free space") as u32;
                 }
 
-                if let Some(block_index) = self.allocate_in_indirect(*indirect_entry) {
-                    if double_indirect_block.dirty {
+                if let Some((block_index, index_within_indirect)) = self.allocate_in_indirect(*indirect_entry) {
+                    if double_indirect_modified {
                         self.update_block(double_indirect_block);
                     }
-                    return Some(block_index);
+                    let index_within_double = index_within_double_indirect * INODE_PER_BLOCK + index_within_indirect;
+                    return Some((block_index, index_within_double));
                 }
             }
         }
         None
     }
 
-    fn alloc_in_triple_indirect(&mut self, triple_indirect_entry: u32) -> Option<u32> {
+    fn alloc_in_triple_indirect(&mut self, triple_indirect_entry: u32) -> Option<(u32, usize)> {
         let triple_indirect_entry = triple_indirect_entry as usize;
 
         if let Some(block) = self
@@ -122,17 +128,20 @@ impl AyaFS {
             .map(convert::<DataBlock, TripleIndirectBlock>)
         {
             let mut triple_indirect_block = block.clone();
-            for double_indirect_entry in triple_indirect_block.block.double_indirect.iter_mut() {
+            let mut triple_indirect_modified = false;
+            for (index_within_triple_indirect, double_indirect_entry) in triple_indirect_block.block.double_indirect.iter_mut().enumerate() {
                 if self.data_bitmap.query(*double_indirect_entry as usize) == false {
                     triple_indirect_block.dirty = true;
+                    triple_indirect_modified = true;
                     *double_indirect_entry =
                         self.data_bitmap.allocate().expect("No free space") as u32;
                 }
-                if let Some(block_index) = self.alloc_in_double_indirect(*double_indirect_entry) {
-                    if triple_indirect_block.dirty {
+                if let Some((block_index, index_within_double_indirect)) = self.alloc_in_double_indirect(*double_indirect_entry) {
+                    if triple_indirect_modified {
                         self.update_block(triple_indirect_block);
                     }
-                    return Some(block_index);
+                    let index_within_triple = index_within_triple_indirect * INODE_PER_BLOCK * INODE_PER_BLOCK + index_within_double_indirect;
+                    return Some((block_index, index_within_triple));
                 }
             }
         }
@@ -283,3 +292,99 @@ impl AyaFS {
         None
     }
 }
+
+impl AyaFS {
+    fn get_block_index(&mut self, inode: &Inode, mut block_index_within_inode: usize) -> Option<usize> {
+        // direct block
+        if block_index_within_inode < DIRECT_NUMBER {
+            let block_index = inode.direct[block_index_within_inode] as usize;
+            return Some(block_index);
+        } else {
+            block_index_within_inode -= DIRECT_NUMBER;
+        }
+
+        // indirect block
+        let indirect_number = INODE_PER_BLOCK;
+        if block_index_within_inode < indirect_number {
+            return if let Some(indirect_block) =
+                self.get_block::<IndirectBlock>(inode.single_indirect as usize)
+            {
+                let block_index = indirect_block.block.entries[block_index_within_inode] as usize;
+                Some(block_index)
+            } else {
+                None
+            };
+        } else {
+            block_index_within_inode -= indirect_number;
+        }
+
+        // double indirect block
+        let double_indirect_number = INODE_PER_BLOCK * INODE_PER_BLOCK;
+        if block_index_within_inode < double_indirect_number {
+            if let Some(double_indirect_block) =
+                self.get_block::<DoubleIndirectBlock>(inode.double_indirect as usize)
+            {
+                // 取出 double indirect block
+                let indirect_block_index = double_indirect_block.block.indirect
+                    [block_index_within_inode / INODE_PER_BLOCK]
+                    as usize;
+                // 要找的 entry 在 double indirect block 中的第几个 indirect block
+                if let Some(indirect_block) = self.get_block::<IndirectBlock>(indirect_block_index)
+                {
+                    let block_index = indirect_block.block.entries
+                        [block_index_within_inode % INODE_PER_BLOCK]
+                        as usize;
+                    // 拿到 DirectoryBlock 的 index
+                    return Some(block_index)
+                }
+            }
+            return None;
+        } else {
+            block_index_within_inode -= double_indirect_number;
+        }
+
+        // triple indirect block
+        if let Some(triple_indirect_block) =
+            self.get_block::<TripleIndirectBlock>(inode.triple_indirect as usize)
+        {
+            // 取出 triple indirect block
+            let double_indirect_block_index = triple_indirect_block.block.double_indirect
+                [block_index_within_inode / (INODE_PER_BLOCK * INODE_PER_BLOCK)]
+                as usize;
+            // 要找的 entry 在 triple indirect block 中的第几个 double indirect block
+            if let Some(double_indirect_block) =
+                self.get_block::<DoubleIndirectBlock>(double_indirect_block_index)
+            {
+                // 取出 double indirect block
+                let indirect_block_index = double_indirect_block.block.indirect
+                    [block_index_within_inode % (INODE_PER_BLOCK * INODE_PER_BLOCK)
+                    / INODE_PER_BLOCK] as usize;
+                // 要找的 entry 在 double indirect block 中的第几个 indirect block
+                if let Some(indirect_block) = self.get_block::<IndirectBlock>(indirect_block_index)
+                {
+                    let block_index = indirect_block.block.entries
+                        [block_index_within_inode % INODE_PER_BLOCK]
+                        as usize;
+                    // DirectoryBlock 的 index
+                    return Some(block_index)
+                }
+            }
+        }
+
+        None
+    }
+
+    pub(crate) fn access_block<T: Block>(&mut self, inode: &Inode, block_index_within_inode: usize) -> Option<&CachedBlock<T>> {
+        self.get_block_index(inode, block_index_within_inode)
+            .map(|block_index| {
+                self.get_block::<T>(block_index).unwrap() // 可以 unwrap 吧这里 ??
+            })
+    }
+
+    pub(crate) fn access_block_mut<T: Block>(&mut self, inode: &Inode, block_index_within_inode: usize) -> Option<&mut CachedBlock<T>> {
+        self.get_block_index(inode, block_index_within_inode)
+            .map(|block_index| {
+                self.get_block_mut::<T>(block_index).unwrap() // 可以 unwrap 吧这里 ??
+            })
+    }
+}
\ No newline at end of file
diff --git a/src/disk/block.rs b/src/disk/block.rs
index 0058b3e..be3d85a 100644
--- a/src/disk/block.rs
+++ b/src/disk/block.rs
@@ -49,7 +49,7 @@ impl Default for InodeBlock {
 
 impl Block for InodeBlock {}
 
-const FULL_MAP: u32 = 0b111_111_111_111_111;
+const FULL_MAP: u16 = 0b111_111_111_111_111;
 
 #[repr(C)]
 #[derive(Clone)]
@@ -84,7 +84,8 @@ impl Default for DirectoryEntry {
 #[derive(Clone)]
 pub struct DirectoryBlock {
     pub entries: [DirectoryEntry; 15],
-    reserved: [u8; 136],
+    pub occupancy: [u8; 2],
+    reserved: [u8; 134],
 }
 
 impl Default for DirectoryBlock {
@@ -107,7 +108,50 @@ impl Default for DirectoryBlock {
                 DirectoryEntry::default(),
                 DirectoryEntry::default(),
             ],
-            reserved: [0xFF; 136],
+            occupancy: [0x80, 0x00], // 0b1000_0000
+            reserved: [0xFF; 134],
+        }
+    }
+}
+
+impl DirectoryBlock {
+    pub(crate) fn is_full(&self) -> bool {
+        self.occupancy[0] == 0xFF && self.occupancy[1] == 0xFF
+    }
+
+    pub(crate) fn query(&self, mut index: usize) -> bool {
+        if index < 7 { // 0-6, first u8
+            index = index + 1;
+            self.occupancy[0] & (1 << (7 - index)) as u8 != 0
+        } else if index < 15 { // 7-14, second u8
+            index = index - 7;
+            self.occupancy[1] & (1 << (7 - index)) as u8 != 0
+        } else {
+            false
+        }
+    }
+
+    pub(crate) fn allocate(&mut self) -> Option<usize> {
+        if self.occupancy[0] != 0xFF {
+            let leading_ones = self.occupancy[0].leading_ones();
+            self.occupancy[0] |= (1 << (7 - leading_ones)) as u8;
+            Some(leading_ones as usize)
+        } else if self.occupancy[1] != 0xFF {
+            let leading_ones = self.occupancy[1].leading_ones();
+            self.occupancy[1] |= (1 << (7 - leading_ones)) as u8;
+            Some(7 + leading_ones as usize)
+        } else {
+            None
+        }
+    }
+
+    pub(crate) fn deallocate(&mut self, mut index: usize) {
+        if index < 7 {
+            index = index + 1;
+            self.occupancy[0] &= !((1 << (7 - index)) as u8);
+        } else if index < 15 { // 7-14, second u8
+            index = index - 7;
+            self.occupancy[1] &= !((1 << (7 - index)) as u8);
         }
     }
 }