Create volume label dir entry when formatting

Fixes #41

Author: rafalh

CHANGELOG.md

@@ -25,6 +25,7 @@ New features:
 * Add `Date::new`, `Time::new`, `DateTime::new` functions that instiantiate corresponding structures after ensuring
   that arguments are in the supported range. They panic if this is not the case.
 * Fix time encoding during a leap second if using `chrono`.
+* Create directory entry with `VOLUME_ID` attribute when formatting if volume label was set in `FormatVolumeOptions`.
 * Remove `byteorder` dependency.
 * Bump up minimal Rust compiler version to 1.46.0.
 * Build the crate using the 2018 edition.

src/fs.rs

@@ -11,7 +11,7 @@ use core::u32;
 
 use crate::boot_sector::{format_boot_sector, BiosParameterBlock, BootSector};
 use crate::dir::{Dir, DirRawStream};
-use crate::dir_entry::{SFN_PADDING, SFN_SIZE};
+use crate::dir_entry::{DirFileEntryData, FileAttributes, SFN_PADDING, SFN_SIZE};
 use crate::error::Error;
 use crate::file::File;
 use crate::io::{self, IoBase, Read, ReadLeExt, Seek, SeekFrom, Write, WriteLeExt};
@@ -1192,7 +1192,12 @@ pub fn format_volume<S: ReadWriteSeek>(storage: &mut S, options: FormatVolumeOpt
         write_zeros(storage, u64::from(bpb.cluster_size()))?;
     }
 
-    // TODO: create volume label dir entry if volume label is set
+    // Create volume label directory entry if volume label is specified in options
+    if let Some(volume_label) = options.volume_label {
+        storage.seek(SeekFrom::Start(root_dir_pos))?;
+        let volume_entry = DirFileEntryData::new(volume_label, FileAttributes::VOLUME_ID);
+        volume_entry.serialize(storage)?;
+    }
 
     storage.seek(SeekFrom::Start(0))?;
     trace!("format_volume end");

tests/format.rs

@@ -116,3 +116,27 @@ fn test_format_1gb_4096sec() {
     let fs = test_format_fs(opts, total_bytes);
     assert_eq!(fs.fat_type(), fatfs::FatType::Fat32);
 }
+
+#[test]
+fn test_format_empty_volume_label() {
+    let total_bytes = 2 * 1024 * MB;
+    let opts = fatfs::FormatVolumeOptions::new();
+    let fs = test_format_fs(opts, total_bytes);
+    assert_eq!(fs.volume_label(), "NO NAME");
+    assert_eq!(fs.read_volume_label_from_root_dir().unwrap(), None);
+}
+
+#[test]
+fn test_format_volume_label_and_id() {
+    let total_bytes = 2 * 1024 * MB;
+    let opts = fatfs::FormatVolumeOptions::new()
+        .volume_id(1234)
+        .volume_label(*b"VOLUMELABEL");
+    let fs = test_format_fs(opts, total_bytes);
+    assert_eq!(fs.volume_label(), "VOLUMELABEL");
+    assert_eq!(
+        fs.read_volume_label_from_root_dir().unwrap(),
+        Some("VOLUMELABEL".to_string())
+    );
+    assert_eq!(fs.volume_id(), 1234);
+}