[pbs-devel] [PATCH proxmox-backup 1/2] tape/drive: add 'set_file_offset' to TapeDriver Trait
Dominik Csapak
d.csapak at proxmox.com
Mon Jun 21 09:59:21 CEST 2021
it seems the LOCATE command behaves slightly different across vendors
e.g. for IBM drives, LOCATE 1 moves to File #2, but
for HP drives, LOCATE 1 move to File #1
since we only want to move forward when correcting, we keep the default
behaviour (for IBM drives), and have an optional offset
that we can set when we detect a discrepancy in target file number and
the actual file number
Signed-off-by: Dominik Csapak <d.csapak at proxmox.com>
---
src/tape/drive/lto/mod.rs | 4 ++++
src/tape/drive/lto/sg_tape.rs | 13 ++++++++++++-
src/tape/drive/mod.rs | 4 ++++
src/tape/drive/virtual_tape.rs | 12 +++++++++++-
4 files changed, 31 insertions(+), 2 deletions(-)
diff --git a/src/tape/drive/lto/mod.rs b/src/tape/drive/lto/mod.rs
index 8c319b07..6db5dc1a 100644
--- a/src/tape/drive/lto/mod.rs
+++ b/src/tape/drive/lto/mod.rs
@@ -286,6 +286,10 @@ impl TapeDriver for LtoTapeHandle {
Ok(())
}
+ fn set_file_offset(&mut self, offset: i64) {
+ self.sg_tape.set_file_offset(offset);
+ }
+
fn move_to_file(&mut self, file: u64) -> Result<(), Error> {
self.locate_file(file)
}
diff --git a/src/tape/drive/lto/sg_tape.rs b/src/tape/drive/lto/sg_tape.rs
index 25c239a2..c9186830 100644
--- a/src/tape/drive/lto/sg_tape.rs
+++ b/src/tape/drive/lto/sg_tape.rs
@@ -122,6 +122,7 @@ pub struct LtoTapeStatus {
pub struct SgTape {
file: File,
+ file_offset: i64,
info: InquiryInfo,
encryption_key_loaded: bool,
}
@@ -143,6 +144,7 @@ impl SgTape {
Ok(Self {
file,
+ file_offset: 0,
info,
encryption_key_loaded: false,
})
@@ -295,12 +297,21 @@ impl SgTape {
Ok(())
}
+ pub fn set_file_offset(&mut self, offset: i64) {
+ self.file_offset = offset;
+ }
+
pub fn locate_file(&mut self, position: u64) -> Result<(), Error> {
if position == 0 {
return self.rewind();
}
- let position = position -1;
+ let position = position - 1;
+ let position = if self.file_offset < 0 {
+ position.saturating_sub((-self.file_offset) as u64)
+ } else {
+ position.saturating_add(self.file_offset as u64)
+ };
let mut sg_raw = SgRaw::new(&mut self.file, 16)?;
sg_raw.set_timeout(Self::SCSI_TAPE_DEFAULT_TIMEOUT);
diff --git a/src/tape/drive/mod.rs b/src/tape/drive/mod.rs
index 7bc02f9e..c853de90 100644
--- a/src/tape/drive/mod.rs
+++ b/src/tape/drive/mod.rs
@@ -80,9 +80,13 @@ pub trait TapeDriver {
/// Move to last file
fn move_to_last_file(&mut self) -> Result<(), Error>;
+ /// Set an offset for 'move_to_file'
+ fn set_file_offset(&mut self, offset: i64);
+
/// Move to given file nr
fn move_to_file(&mut self, file: u64) -> Result<(), Error>;
+
/// Current file number
fn current_file_number(&mut self) -> Result<u64, Error>;
diff --git a/src/tape/drive/virtual_tape.rs b/src/tape/drive/virtual_tape.rs
index 3c5f9502..30841e66 100644
--- a/src/tape/drive/virtual_tape.rs
+++ b/src/tape/drive/virtual_tape.rs
@@ -56,6 +56,7 @@ impl VirtualTapeDrive {
_lock: lock,
drive_name: self.name.clone(),
max_size: self.max_size.unwrap_or(64*1024*1024),
+ file_offset: 0,
path: std::path::PathBuf::from(&self.path),
})
}).map_err(|err: Error| format_err!("open drive '{}' ({}) failed - {}", self.name, self.path, err))
@@ -82,6 +83,7 @@ pub struct VirtualTapeHandle {
drive_name: String,
path: std::path::PathBuf,
max_size: usize,
+ file_offset: i64,
_lock: File,
}
@@ -261,6 +263,10 @@ impl TapeDriver for VirtualTapeHandle {
Ok(())
}
+ fn set_file_offset(&mut self, offset: i64) {
+ self.file_offset = offset;
+ }
+
fn move_to_file(&mut self, file: u64) -> Result<(), Error> {
let mut status = self.load_status()?;
match status.current_tape {
@@ -273,7 +279,11 @@ impl TapeDriver for VirtualTapeHandle {
bail!("invalid file nr");
}
- *pos = file as usize;
+ *pos = if self.file_offset < 0 {
+ file.saturating_sub((-self.file_offset) as u64) as usize
+ } else {
+ file.saturating_add(self.file_offset as u64) as usize
+ };
self.store_status(&status)
.map_err(|err| io::Error::new(io::ErrorKind::Other, err.to_string()))?;
--
2.20.1
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