Add overwrite of a small file with a large one

alloncm · Sep 30, 2023 · 463ba8c · 463ba8c
1 parent 9af4161
commit 463ba8c
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Showing 2 changed files with 14 additions and 13 deletions.
diff --git a/rpi/Cargo.toml b/rpi/Cargo.toml
@@ -12,7 +12,7 @@ magenboy_common = {path = "../common"}
 log = "0.4"
 cfg-if = "1"
 bitfield-struct = "0.5"
-arrayvec = {version = "0.7", default-features = false}
+arrayvec = {version = "0.7", default-features = false}      # Also contains Stack String which is nice
 libc = {version = "0.2", optional = true}
 nix = {version = "0.24", optional = true}
 crossbeam-channel = {version = "0.5", optional = true}

diff --git a/rpi/src/drivers/fat32/mod.rs b/rpi/src/drivers/fat32/mod.rs
@@ -122,9 +122,10 @@ struct FatLongDirEntry{
     name3:[u16;2]
 }
 
-pub(self) const SECTOR_SIZE:usize             = Disk::get_block_size() as usize;
+pub(self) const SECTOR_SIZE:usize   = Disk::get_block_size() as usize;
 const DISK_PARTITION_INDEX:u8       = 0;
 const FAT_ENTRY_EOF_INDEX:u32       = 0x0FFF_FFFF;
+const FAT_ENTRY_FREE_INDEX:u32      = 0;
 const DELETED_DIR_ENTRY_PREFIX:u8   = 0xE5;
 const DIR_EOF_PREFIX:u8             = 0;
 
@@ -381,7 +382,6 @@ impl Fat32Fs{
             cluster_counter += clusters_sequence;
             clusters_sequence = 1;
         }
-        // TODO: verify all the file has been read
     }
 
     /// Write a file to the root dir
@@ -392,24 +392,25 @@ impl Fat32Fs{
         let (name, extension) = self.create_filename(filename).unwrap_or_else(|_|core::panic!("File name format is bad: {}", filename));
         // check if file exists, if exists try to overwrite it, if cant mark it as deleted
         if let Some(existing_entry) = self.root_dir_cache.as_mut_slice().into_iter().find(|d|d.file_name == name && d.file_extension == extension){
+            let segment = self.fat_table_cache.as_slice().into_iter().find(|f|f.start_index == existing_entry.get_first_cluster_index()).unwrap().clone();
+            let segment_len = match segment.state {
+                FatSegmentState::Allocated => segment.len + 1,
+                FatSegmentState::AllocatedEof => 1,
+                _ => core::panic!("FAT32 FS Error: received not allocated segment"),
+            };
+            let mut fat_buffer:FatBuffer = FatBuffer::new(self.fat_info, existing_entry.get_first_cluster_index() as usize, Some(segment_len as usize), &mut self.disk);
             if (existing_entry.size as usize) < content.len(){
                 existing_entry.file_name[0] = DELETED_DIR_ENTRY_PREFIX;
-                // TODO: mark the fat entries as free
+                // Mark the fat entries as free
+                while fat_buffer.write(FAT_ENTRY_FREE_INDEX).is_ok() {}
+                fat_buffer.flush(&mut self.disk);
             }
             else{
                 let existing_entry = existing_entry.clone();        // Shadow the original in order to satisfy the borrow checker
-                let mut segment = self.fat_table_cache.as_slice().into_iter().find(|f|f.start_index == existing_entry.get_first_cluster_index()).unwrap().clone();
-                match segment.state {
-                    FatSegmentState::Allocated => segment.len += 1,
-                    FatSegmentState::AllocatedEof => {},
-                    _ => core::panic!("Error received not allocated segment"),
-                }
-                let mut fat_buffer:FatBuffer = FatBuffer::new(self.fat_info, existing_entry.get_first_cluster_index() as usize, Some(segment.len as usize), &mut self.disk);
                 let mut current_cluster = existing_entry.get_first_cluster_index();
                 let mut cluster_count = 0;
-                while cluster_count < segment.len{
+                while cluster_count < segment_len{
                     self.write_to_data_section(content, current_cluster);
-
                     current_cluster = fat_buffer.read().ok().unwrap();
                     cluster_count += 1;
                 }