tape: media_pool: implement guess_next_writable_media()
This commit is contained in:
Dietmar Maurer
parent
4bb3876352
commit
1d3ae83359
@ -406,119 +406,11 @@ impl MediaPool {
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Ok(())
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}
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/// Allocates a writable media to the current media set
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pub fn alloc_writable_media(&mut self, current_time: i64) -> Result<Uuid, Error> {
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if self.current_media_set_lock.is_none() {
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bail!("alloc_writable_media: media set is not locked - internal error");
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}
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let last_is_writable = self.current_set_usable()?;
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if last_is_writable {
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let last_uuid = self.current_media_set.last_media_uuid().unwrap();
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let media = self.lookup_media(last_uuid)?;
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return Ok(media.uuid().clone());
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}
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// try to find empty media in pool, add to media set
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{ // limit pool lock scope
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let _pool_lock = lock_media_pool(&self.state_path, &self.name)?;
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self.inventory.reload()?;
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let media_list = self.list_media();
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let mut empty_media = Vec::new();
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let mut used_media = Vec::new();
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for media in media_list.into_iter() {
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if !self.location_is_available(media.location()) {
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continue;
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}
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// already part of a media set?
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if media.media_set_label().is_some() {
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used_media.push(media);
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} else {
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// only consider writable empty media
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if media.status() == &MediaStatus::Writable {
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empty_media.push(media);
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}
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}
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}
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// sort empty_media, newest first -> oldest last
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empty_media.sort_unstable_by(|a, b| {
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let mut res = b.label().ctime.cmp(&a.label().ctime);
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if res == std::cmp::Ordering::Equal {
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res = b.label().label_text.cmp(&a.label().label_text);
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}
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res
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});
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if let Some(media) = empty_media.pop() {
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// found empty media, add to media set an use it
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let uuid = media.uuid().clone();
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self.add_media_to_current_set(media.into_id(), current_time)?;
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return Ok(uuid);
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}
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println!("no empty media in pool, try to reuse expired media");
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let mut expired_media = Vec::new();
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for media in used_media.into_iter() {
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if let Some(set) = media.media_set_label() {
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if &set.uuid == self.current_media_set.uuid() {
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continue;
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}
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} else {
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continue;
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}
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if self.media_is_expired(&media, current_time) {
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println!("found expired media on media '{}'", media.label_text());
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expired_media.push(media);
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}
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}
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// sort expired_media, newest first -> oldest last
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expired_media.sort_unstable_by(|a, b| {
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let mut res = b.media_set_label().unwrap().ctime.cmp(&a.media_set_label().unwrap().ctime);
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if res == std::cmp::Ordering::Equal {
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res = b.label().label_text.cmp(&a.label().label_text);
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}
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res
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});
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while let Some(media) = expired_media.pop() {
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// check if we can modify the media-set (i.e. skip
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// media used by a restore job)
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if let Ok(_media_set_lock) = lock_media_set(
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&self.state_path,
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&media.media_set_label().unwrap().uuid,
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Some(std::time::Duration::new(0, 0)), // do not wait
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) {
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println!("reuse expired media '{}'", media.label_text());
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let uuid = media.uuid().clone();
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self.add_media_to_current_set(media.into_id(), current_time)?;
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return Ok(uuid);
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}
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}
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}
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println!("no expired media in pool, try to find unassigned/free media");
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// try unassigned media
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let _lock = lock_unassigned_media_pool(&self.state_path)?;
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self.inventory.reload()?;
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// Get next unassigned media (media not assigned to any pool)
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pub fn next_unassigned_media(&self, media_list: &[MediaId]) -> Option<MediaId> {
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let mut free_media = Vec::new();
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for media_id in self.inventory.list_unassigned_media() {
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for media_id in media_list {
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let (status, location) = self.compute_media_state(&media_id);
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if media_id.media_set_label.is_some() { continue; } // should not happen
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@ -542,8 +434,184 @@ impl MediaPool {
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res
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});
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if let Some(media_id) = free_media.pop() {
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println!("use free media '{}'", media_id.label.label_text);
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free_media.pop().map(|e| e.clone())
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}
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// Get next empty media
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pub fn next_empty_media(&self, media_list: &[BackupMedia]) -> Option<MediaId> {
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let mut empty_media = Vec::new();
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for media in media_list.into_iter() {
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if !self.location_is_available(media.location()) {
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continue;
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}
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// already part of a media set?
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if media.media_set_label().is_none() {
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// only consider writable empty media
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if media.status() == &MediaStatus::Writable {
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empty_media.push(media);
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}
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}
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}
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// sort empty_media, newest first -> oldest last
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empty_media.sort_unstable_by(|a, b| {
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let mut res = b.label().ctime.cmp(&a.label().ctime);
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if res == std::cmp::Ordering::Equal {
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res = b.label().label_text.cmp(&a.label().label_text);
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}
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res
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});
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empty_media.pop().map(|e| e.clone().into_id())
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}
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// Get next expired media
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pub fn next_expired_media(&self, current_time: i64, media_list: &[BackupMedia]) -> Option<MediaId> {
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let mut used_media = Vec::new();
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for media in media_list.into_iter() {
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if !self.location_is_available(media.location()) {
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continue;
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}
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// already part of a media set?
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if media.media_set_label().is_some() {
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used_media.push(media);
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}
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}
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let mut expired_media = Vec::new();
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for media in used_media.into_iter() {
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if let Some(set) = media.media_set_label() {
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if &set.uuid == self.current_media_set.uuid() {
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continue;
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}
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} else {
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continue;
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}
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if !self.media_is_expired(&media, current_time) {
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continue;
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}
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expired_media.push(media);
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}
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// sort expired_media, newest first -> oldest last
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expired_media.sort_unstable_by(|a, b| {
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let mut res = b.media_set_label().unwrap().ctime.cmp(&a.media_set_label().unwrap().ctime);
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if res == std::cmp::Ordering::Equal {
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res = b.label().label_text.cmp(&a.label().label_text);
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}
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res
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});
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if self.no_media_set_locking {
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expired_media.pop().map(|e| e.clone().into_id())
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} else {
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while let Some(media) = expired_media.pop() {
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// check if we can modify the media-set (i.e. skip
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// media used by a restore job)
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if let Ok(_media_set_lock) = lock_media_set(
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&self.state_path,
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&media.media_set_label().unwrap().uuid,
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Some(std::time::Duration::new(0, 0)), // do not wait
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) {
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return Some(media.clone().into_id());
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}
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}
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None
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}
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}
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/// Guess next writable media
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///
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/// Like alloc_writable_media(), but does not really allocate
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/// anything (thus it does not need any locks)
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// Note: Please keep in sync with alloc_writable_media()
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pub fn guess_next_writable_media(&self, current_time: i64) -> Result<MediaId, Error> {
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let last_is_writable = self.current_set_usable()?;
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if last_is_writable {
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let last_uuid = self.current_media_set.last_media_uuid().unwrap();
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let media = self.lookup_media(last_uuid)?;
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return Ok(media.into_id());
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}
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let media_list = self.list_media();
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if let Some(media_id) = self.next_empty_media(&media_list) {
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return Ok(media_id);
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}
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if let Some(media_id) = self.next_expired_media(current_time, &media_list) {
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return Ok(media_id);
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}
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let unassigned_list = self.inventory.list_unassigned_media();
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if let Some(media_id) = self.next_unassigned_media(&unassigned_list) {
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return Ok(media_id);
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}
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bail!("guess_next_writable_media in pool '{}' failed: no usable media found", self.name());
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}
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/// Allocates a writable media to the current media set
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// Note: Please keep in sync with guess_next_writable_media()
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pub fn alloc_writable_media(&mut self, current_time: i64) -> Result<Uuid, Error> {
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if self.current_media_set_lock.is_none() {
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bail!("alloc_writable_media: media set is not locked - internal error");
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}
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let last_is_writable = self.current_set_usable()?;
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if last_is_writable {
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let last_uuid = self.current_media_set.last_media_uuid().unwrap();
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let media = self.lookup_media(last_uuid)?;
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return Ok(media.uuid().clone());
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}
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{ // limit pool lock scope
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let _pool_lock = lock_media_pool(&self.state_path, &self.name)?;
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self.inventory.reload()?;
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let media_list = self.list_media();
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// try to find empty media in pool, add to media set
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if let Some(media_id) = self.next_empty_media(&media_list) {
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// found empty media, add to media set an use it
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println!("found empty media '{}'", media_id.label.label_text);
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let uuid = media_id.label.uuid.clone();
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self.add_media_to_current_set(media_id, current_time)?;
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return Ok(uuid);
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}
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println!("no empty media in pool, try to reuse expired media");
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if let Some(media_id) = self.next_expired_media(current_time, &media_list) {
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// found expired media, add to media set an use it
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println!("reuse expired media '{}'", media_id.label.label_text);
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let uuid = media_id.label.uuid.clone();
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self.add_media_to_current_set(media_id, current_time)?;
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return Ok(uuid);
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}
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}
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println!("no empty or expired media in pool, try to find unassigned/free media");
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// try unassigned media
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let _lock = lock_unassigned_media_pool(&self.state_path)?;
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self.inventory.reload()?;
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let unassigned_list = self.inventory.list_unassigned_media();
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if let Some(media_id) = self.next_unassigned_media(&unassigned_list) {
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println!("use free/unassigned media '{}'", media_id.label.label_text);
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let uuid = media_id.label.uuid.clone();
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self.add_media_to_current_set(media_id, current_time)?;
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return Ok(uuid);
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