tape: implement format/erase

src/tape/drive/lto/mod.rs

@@ -179,6 +179,10 @@ impl LtoTapeHandle {
         Ok(status)
     }
 
+    pub fn erase_media(&mut self, fast: bool) -> Result<(), Error> {
+        self.sg_tape.erase_media(fast)
+    }
+
     pub fn load(&mut self) ->  Result<(), Error> {
         self.sg_tape.load()
     }
@@ -223,9 +227,8 @@ impl TapeDriver for LtoTapeHandle {
         self.sg_tape.current_file_number()
     }
 
-    fn erase_media(&mut self, fast: bool) -> Result<(), Error> {
-        self.rewind()?; // important - erase from BOT
-        self.sg_tape.erase_media(fast)
+    fn format_media(&mut self, fast: bool) -> Result<(), Error> {
+        self.sg_tape.format_media(fast)
     }
 
     fn read_next_file<'a>(&'a mut self) -> Result<Option<Box<dyn TapeRead + 'a>>, std::io::Error> {

src/tape/drive/lto/sg_tape.rs

@@ -100,9 +100,48 @@ impl SgTape {
         scsi_inquiry(&mut self.file)
     }
 
-    pub fn erase_media(&mut self, _fast: bool) -> Result<(), Error> {
-        // fixme:
-        unimplemented!();
+    /// Erase medium.
+    ///
+    /// EOD is written at the current position, which marks it as end
+    /// of data. After the command is successfully completed, the
+    /// drive is positioned immediately before End Of Data (not End Of
+    /// Tape).
+    pub fn erase_media(&mut self, fast: bool) -> Result<(), Error> {
+        let mut sg_raw = SgRaw::new(&mut self.file, 16)?;
+        sg_raw.set_timeout(Self::SCSI_TAPE_DEFAULT_TIMEOUT);
+        let mut cmd = Vec::new();
+        cmd.push(0x19);
+        if fast {
+            cmd.push(0); // LONG=0
+        } else {
+            cmd.push(1); // LONG=1
+        }
+        cmd.extend(&[0, 0, 0, 0]);
+
+        sg_raw.do_command(&cmd)
+            .map_err(|err| format_err!("erase failed - {}", err))?;
+
+        Ok(())
+    }
+
+    /// Format media, single partition
+    pub fn format_media(&mut self, fast: bool) -> Result<(), Error> {
+
+        self.rewind()?;
+
+        let mut sg_raw = SgRaw::new(&mut self.file, 16)?;
+        sg_raw.set_timeout(Self::SCSI_TAPE_DEFAULT_TIMEOUT);
+        let mut cmd = Vec::new();
+        cmd.extend(&[0x04, 0, 0, 0, 0, 0]);
+
+        sg_raw.do_command(&cmd)
+            .map_err(|err| format_err!("erase failed - {}", err))?;
+
+        if !fast {
+            self.erase_media(false)?; // overwrite everything
+        }
+
+        Ok(())
     }
 
     pub fn rewind(&mut self) -> Result<(), Error> {

src/tape/drive/mod.rs

@@ -111,7 +111,7 @@ pub trait TapeDriver {
     fn current_file_number(&mut self) -> Result<u64, Error>;
 
     /// Completely erase the media
-    fn erase_media(&mut self, fast: bool) -> Result<(), Error>;
+    fn format_media(&mut self, fast: bool) -> Result<(), Error>;
 
     /// Read/Open the next file
     fn read_next_file<'a>(&'a mut self) -> Result<Option<Box<dyn TapeRead + 'a>>, std::io::Error>;
@@ -122,11 +122,9 @@ pub trait TapeDriver {
     /// Write label to tape (erase tape content)
     fn label_tape(&mut self, label: &MediaLabel) -> Result<(), Error> {
 
-        self.rewind()?;
-
         self.set_encryption(None)?;
 
-        self.erase_media(true)?;
+        self.format_media(true)?; // this rewinds the tape
 
         let raw = serde_json::to_string_pretty(&serde_json::to_value(&label)?)?;
 

src/tape/drive/virtual_tape.rs

@@ -360,7 +360,7 @@ impl TapeDriver for VirtualTapeHandle {
         }
     }
 
-    fn erase_media(&mut self, _fast: bool) -> Result<(), Error> {
+    fn format_media(&mut self, _fast: bool) -> Result<(), Error> {
         let mut status = self.load_status()?;
         match status.current_tape {
             Some(VirtualTapeStatus { ref name, ref mut pos }) => {