tape: add media pool handling

This commit is contained in:
Dietmar Maurer 2020-12-10 11:41:35 +01:00
parent 9700d5374a
commit c4d8542ec1
2 changed files with 486 additions and 0 deletions

483
src/tape/media_pool.rs Normal file
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@ -0,0 +1,483 @@
//! Media Pool
//!
//! A set of backup medias.
//!
//! This struct manages backup media state during backup. The main
//! purpose ist to allocate media sets and assing new tapes to it.
//!
//!
use std::path::Path;
use anyhow::{bail, Error};
use ::serde::{Deserialize, Serialize};
use proxmox::tools::Uuid;
use crate::{
api2::types::{
MediaStatus,
MediaSetPolicy,
RetentionPolicy,
MediaPoolConfig,
},
tools::systemd::time::compute_next_event,
tape::{
MediaId,
MediaSet,
MediaLocation,
Inventory,
MediaStateDatabase,
file_formats::{
DriveLabel,
MediaSetLabel,
},
}
};
pub struct MediaPoolLockGuard(std::fs::File);
/// Media Pool
pub struct MediaPool {
name: String,
media_set_policy: MediaSetPolicy,
retention: RetentionPolicy,
inventory: Inventory,
state_db: MediaStateDatabase,
current_media_set: MediaSet,
}
impl MediaPool {
/// Creates a new instance
pub fn new(
name: &str,
state_path: &Path,
media_set_policy: MediaSetPolicy,
retention: RetentionPolicy,
) -> Result<Self, Error> {
let inventory = Inventory::load(state_path)?;
let current_media_set = match inventory.latest_media_set(name) {
Some(set_uuid) => inventory.compute_media_set_members(&set_uuid)?,
None => MediaSet::new(),
};
let state_db = MediaStateDatabase::load(state_path)?;
Ok(MediaPool {
name: String::from(name),
media_set_policy,
retention,
inventory,
state_db,
current_media_set,
})
}
/// Creates a new instance using the media pool configuration
pub fn with_config(
name: &str,
state_path: &Path,
config: &MediaPoolConfig,
) -> Result<Self, Error> {
let allocation = config.allocation.clone().unwrap_or(String::from("continue")).parse()?;
let retention = config.retention.clone().unwrap_or(String::from("keep")).parse()?;
MediaPool::new(name, state_path, allocation, retention)
}
/// Returns the pool name
pub fn name(&self) -> &str {
&self.name
}
fn compute_media_state(&self, media_id: &MediaId) -> (MediaStatus, MediaLocation) {
let (status, location) = self.state_db.status_and_location(&media_id.label.uuid);
match status {
MediaStatus::Full | MediaStatus::Damaged | MediaStatus::Retired => {
return (status, location);
}
MediaStatus::Unknown | MediaStatus::Writable => {
/* possibly writable - fall through to check */
}
}
let set = match media_id.media_set_label {
None => return (MediaStatus::Writable, location), // not assigned to any pool
Some(ref set) => set,
};
if set.pool != self.name { // should never trigger
return (MediaStatus::Unknown, location); // belong to another pool
}
if set.uuid.as_ref() == [0u8;16] { // not assigned to any pool
return (MediaStatus::Writable, location);
}
if &set.uuid != self.current_media_set.uuid() {
return (MediaStatus::Full, location); // assume FULL
}
// media is member of current set
if self.current_media_set.is_last_media(&media_id.label.uuid) {
(MediaStatus::Writable, location) // last set member is writable
} else {
(MediaStatus::Full, location)
}
}
/// Returns the 'MediaId' with associated state
pub fn lookup_media(&self, uuid: &Uuid) -> Result<BackupMedia, Error> {
let media_id = match self.inventory.lookup_media(uuid) {
None => bail!("unable to lookup media {}", uuid),
Some(media_id) => media_id.clone(),
};
if let Some(ref set) = media_id.media_set_label {
if set.pool != self.name {
bail!("media does not belong to pool ({} != {})", set.pool, self.name);
}
}
let (status, location) = self.compute_media_state(&media_id);
Ok(BackupMedia::with_media_id(
media_id,
location,
status,
))
}
/// List all media associated with this pool
pub fn list_media(&self) -> Vec<BackupMedia> {
let media_id_list = self.inventory.list_pool_media(&self.name);
media_id_list.into_iter()
.map(|media_id| {
let (status, location) = self.compute_media_state(&media_id);
BackupMedia::with_media_id(
media_id,
location,
status,
)
})
.collect()
}
/// Set media status to FULL.
pub fn set_media_status_full(&mut self, uuid: &Uuid) -> Result<(), Error> {
let media = self.lookup_media(uuid)?; // check if media belongs to this pool
if media.status() != &MediaStatus::Full {
self.state_db.set_media_status_full(uuid)?;
}
Ok(())
}
/// Make sure the current media set is usable for writing
///
/// If not, starts a new media set. Also creates a new
/// set if media_set_policy implies it.
pub fn start_write_session(&mut self, current_time: i64) -> Result<(), Error> {
let mut create_new_set = match self.current_set_usable() {
Err(err) => {
eprintln!("unable to use current media set - {}", err);
true
}
Ok(usable) => !usable,
};
if !create_new_set {
match &self.media_set_policy {
MediaSetPolicy::AlwaysCreate => {
create_new_set = true;
}
MediaSetPolicy::CreateAt(event) => {
if let Some(set_start_time) = self.inventory.media_set_start_time(&self.current_media_set.uuid()) {
if let Ok(Some(alloc_time)) = compute_next_event(event, set_start_time as i64, false) {
if current_time >= alloc_time {
create_new_set = true;
}
}
}
}
MediaSetPolicy::ContinueCurrent => { /* do nothing here */ }
}
}
if create_new_set {
let media_set = MediaSet::new();
eprintln!("starting new media set {}", media_set.uuid());
self.current_media_set = media_set;
}
Ok(())
}
/// List media in current media set
pub fn current_media_list(&self) -> Result<Vec<&Uuid>, Error> {
let mut list = Vec::new();
for opt_uuid in self.current_media_set.media_list().iter() {
match opt_uuid {
Some(ref uuid) => list.push(uuid),
None => bail!("current_media_list failed - media set is incomplete"),
}
}
Ok(list)
}
// tests if the media data is considered as expired at sepcified time
pub fn media_is_expired(&self, media: &BackupMedia, current_time: i64) -> bool {
if media.status() != &MediaStatus::Full {
return false;
}
let expire_time = self.inventory.media_expire_time(
media.id(), &self.media_set_policy, &self.retention);
current_time > expire_time
}
/// Allocates a writable media to the current media set
pub fn alloc_writable_media(&mut self, current_time: i64) -> Result<Uuid, Error> {
let last_is_writable = self.current_set_usable()?;
let pool = self.name.clone();
if last_is_writable {
let last_uuid = self.current_media_set.last_media_uuid().unwrap();
let media = self.lookup_media(last_uuid)?;
return Ok(media.uuid().clone());
}
// try to find empty media in pool, add to media set
let mut media_list = self.list_media();
let mut empty_media = Vec::new();
for media in media_list.iter_mut() {
// already part of a media set?
if media.media_set_label().is_some() { continue; }
// check if media is on site
match media.location() {
MediaLocation::Online(_) | MediaLocation::Offline => { /* OK */ },
MediaLocation::Vault(_) => continue,
}
// only consider writable media
if media.status() != &MediaStatus::Writable { continue; }
empty_media.push(media);
}
// sort empty_media, oldest media first
empty_media.sort_unstable_by_key(|media| media.label().ctime);
if let Some(media) = empty_media.first_mut() {
// found empty media, add to media set an use it
let seq_nr = self.current_media_set.media_list().len() as u64;
let set = MediaSetLabel::with_data(&pool, self.current_media_set.uuid().clone(), seq_nr, current_time);
media.set_media_set_label(set);
self.inventory.store(media.id().clone())?; // store persistently
self.current_media_set.add_media(media.uuid().clone());
return Ok(media.uuid().clone());
}
println!("no empty media in pool, try to reuse expired media");
let mut expired_media = Vec::new();
for media in media_list.into_iter() {
if let Some(set) = media.media_set_label() {
if &set.uuid == self.current_media_set.uuid() {
continue;
}
}
if self.media_is_expired(&media, current_time) {
println!("found expired media on media '{}'", media.changer_id());
expired_media.push(media);
}
}
// sort, oldest media first
expired_media.sort_unstable_by_key(|media| {
match media.media_set_label() {
None => 0, // should not happen here
Some(set) => set.ctime,
}
});
match expired_media.first_mut() {
None => {
bail!("alloc writable media in pool '{}' failed: no usable media found", self.name());
}
Some(media) => {
println!("reuse expired media '{}'", media.changer_id());
let seq_nr = self.current_media_set.media_list().len() as u64;
let set = MediaSetLabel::with_data(&pool, self.current_media_set.uuid().clone(), seq_nr, current_time);
media.set_media_set_label(set);
self.inventory.store(media.id().clone())?; // store persistently
self.state_db.clear_media_status(media.uuid())?; // remove Full status
self.current_media_set.add_media(media.uuid().clone());
return Ok(media.uuid().clone());
}
}
}
/// check if the current media set is usable for writing
///
/// This does several consistency checks, and return if
/// the last media in the current set is in writable state.
///
/// This return error when the media set must not be used any
/// longer because of consistency errors.
pub fn current_set_usable(&self) -> Result<bool, Error> {
let media_count = self.current_media_set.media_list().len();
if media_count == 0 {
return Ok(false);
}
let set_uuid = self.current_media_set.uuid();
let mut last_is_writable = false;
for (seq, opt_uuid) in self.current_media_set.media_list().iter().enumerate() {
let uuid = match opt_uuid {
None => bail!("media set is incomplete (missing media information)"),
Some(uuid) => uuid,
};
let media = self.lookup_media(uuid)?;
match media.media_set_label() {
Some(MediaSetLabel { seq_nr, uuid, ..}) if *seq_nr == seq as u64 && uuid == set_uuid => { /* OK */ },
Some(MediaSetLabel { seq_nr, uuid, ..}) if uuid == set_uuid => {
bail!("media sequence error ({} != {})", *seq_nr, seq);
},
Some(MediaSetLabel { uuid, ..}) => bail!("media owner error ({} != {}", uuid, set_uuid),
None => bail!("media owner error (no owner)"),
}
match media.status() {
MediaStatus::Full => { /* OK */ },
MediaStatus::Writable if (seq + 1) == media_count => {
last_is_writable = true;
match media.location() {
MediaLocation::Online(_) | MediaLocation::Offline => { /* OK */ },
MediaLocation::Vault(vault) => {
bail!("writable media offsite in vault '{}'", vault);
}
}
},
_ => bail!("unable to use media set - wrong media status {:?}", media.status()),
}
}
Ok(last_is_writable)
}
/// Generate a human readable name for the media set
pub fn generate_media_set_name(
&self,
media_set_uuid: &Uuid,
template: Option<String>,
) -> Result<String, Error> {
self.inventory.generate_media_set_name(media_set_uuid, template)
}
/// Lock the pool
pub fn lock(base_path: &Path, name: &str) -> Result<MediaPoolLockGuard, Error> {
let mut path = base_path.to_owned();
path.push(format!(".{}", name));
path.set_extension("lck");
let timeout = std::time::Duration::new(10, 0);
let lock = proxmox::tools::fs::open_file_locked(&path, timeout, true)?;
Ok(MediaPoolLockGuard(lock))
}
}
/// Backup media
///
/// Combines 'MediaId' with 'MediaLocation' and 'MediaStatus'
/// information.
#[derive(Debug,Serialize,Deserialize,Clone)]
pub struct BackupMedia {
/// Media ID
id: MediaId,
/// Media location
location: MediaLocation,
/// Media status
status: MediaStatus,
}
impl BackupMedia {
/// Creates a new instance
pub fn with_media_id(
id: MediaId,
location: MediaLocation,
status: MediaStatus,
) -> Self {
Self { id, location, status }
}
/// Returns the media location
pub fn location(&self) -> &MediaLocation {
&self.location
}
/// Returns the media status
pub fn status(&self) -> &MediaStatus {
&self.status
}
/// Returns the media uuid
pub fn uuid(&self) -> &Uuid {
&self.id.label.uuid
}
/// Returns the media set label
pub fn media_set_label(&self) -> &Option<MediaSetLabel> {
&self.id.media_set_label
}
/// Updates the media set label
pub fn set_media_set_label(&mut self, set_label: MediaSetLabel) {
self.id.media_set_label = Some(set_label);
}
/// Returns the drive label
pub fn label(&self) -> &DriveLabel {
&self.id.label
}
/// Returns the media id (drive label + media set label)
pub fn id(&self) -> &MediaId {
&self.id
}
/// Returns the media label (Barcode)
pub fn changer_id(&self) -> &str {
&self.id.label.changer_id
}
}

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@ -31,6 +31,9 @@ pub use media_state_database::*;
mod online_status_map;
pub use online_status_map::*;
mod media_pool;
pub use media_pool::*;
/// Directory path where we store all tape status information
pub const TAPE_STATUS_DIR: &str = "/var/lib/proxmox-backup/tape";