Line data Source code
1 : use std::ops::{Deref, DerefMut};
2 : use std::sync::Arc;
3 :
4 : use anyhow::Context;
5 : use pageserver_api::models::TimelineState;
6 : use pageserver_api::shard::TenantShardId;
7 : use remote_storage::DownloadError;
8 : use tokio::sync::OwnedMutexGuard;
9 : use tracing::{Instrument, error, info, info_span, instrument};
10 : use utils::id::TimelineId;
11 : use utils::{crashsafe, fs_ext, pausable_failpoint};
12 :
13 : use crate::config::PageServerConf;
14 : use crate::context::RequestContext;
15 : use crate::task_mgr::{self, TaskKind};
16 : use crate::tenant::metadata::TimelineMetadata;
17 : use crate::tenant::remote_timeline_client::{
18 : PersistIndexPartWithDeletedFlagError, RemoteTimelineClient,
19 : };
20 : use crate::tenant::{
21 : CreateTimelineCause, DeleteTimelineError, MaybeDeletedIndexPart, Tenant, TenantManifestError,
22 : Timeline, TimelineOrOffloaded,
23 : };
24 : use crate::virtual_file::MaybeFatalIo;
25 :
26 : /// Mark timeline as deleted in S3 so we won't pick it up next time
27 : /// during attach or pageserver restart.
28 : /// See comment in persist_index_part_with_deleted_flag.
29 0 : async fn set_deleted_in_remote_index(
30 0 : remote_client: &Arc<RemoteTimelineClient>,
31 0 : ) -> Result<(), DeleteTimelineError> {
32 0 : let res = remote_client.persist_index_part_with_deleted_flag().await;
33 0 : match res {
34 : // If we (now, or already) marked it successfully as deleted, we can proceed
35 0 : Ok(()) | Err(PersistIndexPartWithDeletedFlagError::AlreadyDeleted(_)) => (),
36 : // Bail out otherwise
37 : //
38 : // AlreadyInProgress shouldn't happen, because the 'delete_lock' prevents
39 : // two tasks from performing the deletion at the same time. The first task
40 : // that starts deletion should run it to completion.
41 0 : Err(e @ PersistIndexPartWithDeletedFlagError::AlreadyInProgress(_))
42 0 : | Err(e @ PersistIndexPartWithDeletedFlagError::Other(_)) => {
43 0 : return Err(DeleteTimelineError::Other(anyhow::anyhow!(e)));
44 : }
45 : }
46 0 : Ok(())
47 0 : }
48 :
49 : /// Grab the compaction and gc locks, and actually perform the deletion.
50 : ///
51 : /// The locks prevent GC or compaction from running at the same time. The background tasks do not
52 : /// register themselves with the timeline it's operating on, so it might still be running even
53 : /// though we called `shutdown_tasks`.
54 : ///
55 : /// Note that there are still other race conditions between
56 : /// GC, compaction and timeline deletion. See
57 : /// <https://github.com/neondatabase/neon/issues/2671>
58 : ///
59 : /// No timeout here, GC & Compaction should be responsive to the
60 : /// `TimelineState::Stopping` change.
61 : // pub(super): documentation link
62 4 : pub(super) async fn delete_local_timeline_directory(
63 4 : conf: &PageServerConf,
64 4 : tenant_shard_id: TenantShardId,
65 4 : timeline: &Timeline,
66 4 : ) {
67 4 : // Always ensure the lock order is compaction -> gc.
68 4 : let compaction_lock = timeline.compaction_lock.lock();
69 4 : let _compaction_lock = crate::timed(
70 4 : compaction_lock,
71 4 : "acquires compaction lock",
72 4 : std::time::Duration::from_secs(5),
73 4 : )
74 4 : .await;
75 :
76 4 : let gc_lock = timeline.gc_lock.lock();
77 4 : let _gc_lock = crate::timed(
78 4 : gc_lock,
79 4 : "acquires gc lock",
80 4 : std::time::Duration::from_secs(5),
81 4 : )
82 4 : .await;
83 :
84 : // NB: storage_sync upload tasks that reference these layers have been cancelled
85 : // by the caller.
86 :
87 4 : let local_timeline_directory = conf.timeline_path(&tenant_shard_id, &timeline.timeline_id);
88 4 :
89 4 : // NB: This need not be atomic because the deleted flag in the IndexPart
90 4 : // will be observed during tenant/timeline load. The deletion will be resumed there.
91 4 : //
92 4 : // ErrorKind::NotFound can happen e.g. if we race with tenant detach, because,
93 4 : // no locks are shared.
94 4 : tokio::fs::remove_dir_all(local_timeline_directory)
95 4 : .await
96 4 : .or_else(fs_ext::ignore_not_found)
97 4 : .fatal_err("removing timeline directory");
98 4 :
99 4 : // Make sure previous deletions are ordered before mark removal.
100 4 : // Otherwise there is no guarantee that they reach the disk before mark deletion.
101 4 : // So its possible for mark to reach disk first and for other deletions
102 4 : // to be reordered later and thus missed if a crash occurs.
103 4 : // Note that we dont need to sync after mark file is removed
104 4 : // because we can tolerate the case when mark file reappears on startup.
105 4 : let timeline_path = conf.timelines_path(&tenant_shard_id);
106 4 : crashsafe::fsync_async(timeline_path)
107 4 : .await
108 4 : .fatal_err("fsync after removing timeline directory");
109 4 :
110 4 : info!("finished deleting layer files, releasing locks");
111 4 : }
112 :
113 : /// It is important that this gets called when DeletionGuard is being held.
114 : /// For more context see comments in [`make_timeline_delete_guard`]
115 0 : async fn remove_maybe_offloaded_timeline_from_tenant(
116 0 : tenant: &Tenant,
117 0 : timeline: &TimelineOrOffloaded,
118 0 : _: &DeletionGuard, // using it as a witness
119 0 : ) -> anyhow::Result<()> {
120 0 : // Remove the timeline from the map.
121 0 : // This observes the locking order between timelines and timelines_offloaded
122 0 : let mut timelines = tenant.timelines.lock().unwrap();
123 0 : let mut timelines_offloaded = tenant.timelines_offloaded.lock().unwrap();
124 0 : let offloaded_children_exist = timelines_offloaded
125 0 : .iter()
126 0 : .any(|(_, entry)| entry.ancestor_timeline_id == Some(timeline.timeline_id()));
127 0 : let children_exist = timelines
128 0 : .iter()
129 0 : .any(|(_, entry)| entry.get_ancestor_timeline_id() == Some(timeline.timeline_id()));
130 0 : // XXX this can happen because of race conditions with branch creation.
131 0 : // We already deleted the remote layer files, so it's probably best to panic.
132 0 : if children_exist || offloaded_children_exist {
133 0 : panic!("Timeline grew children while we removed layer files");
134 0 : }
135 0 :
136 0 : match timeline {
137 0 : TimelineOrOffloaded::Timeline(timeline) => {
138 0 : timelines.remove(&timeline.timeline_id).expect(
139 0 : "timeline that we were deleting was concurrently removed from 'timelines' map",
140 0 : );
141 0 : tenant
142 0 : .scheduled_compaction_tasks
143 0 : .lock()
144 0 : .unwrap()
145 0 : .remove(&timeline.timeline_id);
146 0 : }
147 0 : TimelineOrOffloaded::Offloaded(timeline) => {
148 0 : let offloaded_timeline = timelines_offloaded
149 0 : .remove(&timeline.timeline_id)
150 0 : .expect("timeline that we were deleting was concurrently removed from 'timelines_offloaded' map");
151 0 : offloaded_timeline.delete_from_ancestor_with_timelines(&timelines);
152 0 : }
153 : }
154 :
155 0 : drop(timelines_offloaded);
156 0 : drop(timelines);
157 0 :
158 0 : Ok(())
159 0 : }
160 :
161 : /// Orchestrates timeline shut down of all timeline tasks, removes its in-memory structures,
162 : /// and deletes its data from both disk and s3.
163 : /// The sequence of steps:
164 : /// 1. Set deleted_at in remote index part.
165 : /// 2. Create local mark file.
166 : /// 3. Delete local files except metadata (it is simpler this way, to be able to reuse timeline initialization code that expects metadata)
167 : /// 4. Delete remote layers
168 : /// 5. Delete index part
169 : /// 6. Delete meta, timeline directory
170 : /// 7. Delete mark file
171 : ///
172 : /// It is resumable from any step in case a crash/restart occurs.
173 : /// There are two entrypoints to the process:
174 : /// 1. [`DeleteTimelineFlow::run`] this is the main one called by a management api handler.
175 : /// 2. [`DeleteTimelineFlow::resume_deletion`] is called during restarts when local metadata is still present
176 : /// and we possibly neeed to continue deletion of remote files.
177 : ///
178 : /// Note the only other place that messes around timeline delete mark is the logic that scans directory with timelines during tenant load.
179 : #[derive(Default)]
180 : pub enum DeleteTimelineFlow {
181 : #[default]
182 : NotStarted,
183 : InProgress,
184 : Finished,
185 : }
186 :
187 : impl DeleteTimelineFlow {
188 : // These steps are run in the context of management api request handler.
189 : // Long running steps are continued to run in the background.
190 : // NB: If this fails half-way through, and is retried, the retry will go through
191 : // all the same steps again. Make sure the code here is idempotent, and don't
192 : // error out if some of the shutdown tasks have already been completed!
193 : #[instrument(skip_all)]
194 : pub async fn run(
195 : tenant: &Arc<Tenant>,
196 : timeline_id: TimelineId,
197 : ) -> Result<(), DeleteTimelineError> {
198 : super::debug_assert_current_span_has_tenant_and_timeline_id();
199 :
200 : let (timeline, mut guard) =
201 : make_timeline_delete_guard(tenant, timeline_id, TimelineDeleteGuardKind::Delete)?;
202 :
203 : guard.mark_in_progress()?;
204 :
205 : // Now that the Timeline is in Stopping state, request all the related tasks to shut down.
206 : if let TimelineOrOffloaded::Timeline(timeline) = &timeline {
207 : timeline.shutdown(super::ShutdownMode::Hard).await;
208 : }
209 :
210 : tenant.gc_block.before_delete(&timeline.timeline_id());
211 :
212 0 : fail::fail_point!("timeline-delete-before-index-deleted-at", |_| {
213 0 : Err(anyhow::anyhow!(
214 0 : "failpoint: timeline-delete-before-index-deleted-at"
215 0 : ))?
216 0 : });
217 :
218 : let remote_client = match timeline.maybe_remote_client() {
219 : Some(remote_client) => remote_client,
220 : None => {
221 : let remote_client = tenant
222 : .build_timeline_client(timeline.timeline_id(), tenant.remote_storage.clone());
223 : let result = match remote_client
224 : .download_index_file(&tenant.cancel)
225 : .instrument(info_span!("download_index_file"))
226 : .await
227 : {
228 : Ok(r) => r,
229 : Err(DownloadError::NotFound) => {
230 : // Deletion is already complete
231 : tracing::info!("Timeline already deleted in remote storage");
232 : return Ok(());
233 : }
234 : Err(e) => {
235 : return Err(DeleteTimelineError::Other(anyhow::anyhow!(
236 : "error: {:?}",
237 : e
238 : )));
239 : }
240 : };
241 : let index_part = match result {
242 : MaybeDeletedIndexPart::Deleted(p) => {
243 : tracing::info!("Timeline already set as deleted in remote index");
244 : p
245 : }
246 : MaybeDeletedIndexPart::IndexPart(p) => p,
247 : };
248 : let remote_client = Arc::new(remote_client);
249 :
250 : remote_client
251 : .init_upload_queue(&index_part)
252 : .map_err(DeleteTimelineError::Other)?;
253 : remote_client.shutdown().await;
254 : remote_client
255 : }
256 : };
257 : set_deleted_in_remote_index(&remote_client).await?;
258 :
259 0 : fail::fail_point!("timeline-delete-before-schedule", |_| {
260 0 : Err(anyhow::anyhow!(
261 0 : "failpoint: timeline-delete-before-schedule"
262 0 : ))?
263 0 : });
264 :
265 : Self::schedule_background(
266 : guard,
267 : tenant.conf,
268 : Arc::clone(tenant),
269 : timeline,
270 : remote_client,
271 : );
272 :
273 : Ok(())
274 : }
275 :
276 0 : fn mark_in_progress(&mut self) -> anyhow::Result<()> {
277 0 : match self {
278 0 : Self::Finished => anyhow::bail!("Bug. Is in finished state"),
279 0 : Self::InProgress { .. } => { /* We're in a retry */ }
280 0 : Self::NotStarted => { /* Fresh start */ }
281 : }
282 :
283 0 : *self = Self::InProgress;
284 0 :
285 0 : Ok(())
286 0 : }
287 :
288 : /// Shortcut to create Timeline in stopping state and spawn deletion task.
289 : #[instrument(skip_all, fields(%timeline_id))]
290 : pub(crate) async fn resume_deletion(
291 : tenant: Arc<Tenant>,
292 : timeline_id: TimelineId,
293 : local_metadata: &TimelineMetadata,
294 : remote_client: RemoteTimelineClient,
295 : ctx: &RequestContext,
296 : ) -> anyhow::Result<()> {
297 : // Note: here we even skip populating layer map. Timeline is essentially uninitialized.
298 : // RemoteTimelineClient is the only functioning part.
299 : let (timeline, _timeline_ctx) = tenant
300 : .create_timeline_struct(
301 : timeline_id,
302 : local_metadata,
303 : None, // Ancestor is not needed for deletion.
304 : None, // Previous heatmap is not needed for deletion
305 : tenant.get_timeline_resources_for(remote_client),
306 : // Important. We dont pass ancestor above because it can be missing.
307 : // Thus we need to skip the validation here.
308 : CreateTimelineCause::Delete,
309 : crate::tenant::CreateTimelineIdempotency::FailWithConflict, // doesn't matter what we put here
310 : None, // doesn't matter what we put here
311 : None, // doesn't matter what we put here
312 : ctx,
313 : )
314 : .context("create_timeline_struct")?;
315 :
316 : let mut guard = DeletionGuard(
317 : Arc::clone(&timeline.delete_progress)
318 : .try_lock_owned()
319 : .expect("cannot happen because we're the only owner"),
320 : );
321 :
322 : // We meed to do this because when console retries delete request we shouldnt answer with 404
323 : // because 404 means successful deletion.
324 : {
325 : let mut locked = tenant.timelines.lock().unwrap();
326 : locked.insert(timeline_id, Arc::clone(&timeline));
327 : }
328 :
329 : guard.mark_in_progress()?;
330 :
331 : let remote_client = timeline.remote_client.clone();
332 : let timeline = TimelineOrOffloaded::Timeline(timeline);
333 : Self::schedule_background(guard, tenant.conf, tenant, timeline, remote_client);
334 :
335 : Ok(())
336 : }
337 :
338 0 : fn schedule_background(
339 0 : guard: DeletionGuard,
340 0 : conf: &'static PageServerConf,
341 0 : tenant: Arc<Tenant>,
342 0 : timeline: TimelineOrOffloaded,
343 0 : remote_client: Arc<RemoteTimelineClient>,
344 0 : ) {
345 0 : let tenant_shard_id = timeline.tenant_shard_id();
346 0 : let timeline_id = timeline.timeline_id();
347 :
348 : // Take a tenant gate guard, because timeline deletion needs access to the tenant to update its manifest.
349 0 : let Ok(tenant_guard) = tenant.gate.enter() else {
350 : // It is safe to simply skip here, because we only schedule background work once the timeline is durably marked for deletion.
351 0 : info!("Tenant is shutting down, timeline deletion will be resumed when it next starts");
352 0 : return;
353 : };
354 :
355 : task_mgr::spawn(
356 0 : task_mgr::BACKGROUND_RUNTIME.handle(),
357 0 : TaskKind::TimelineDeletionWorker,
358 0 : tenant_shard_id,
359 0 : Some(timeline_id),
360 0 : "timeline_delete",
361 0 : async move {
362 0 : let _guard = tenant_guard;
363 :
364 0 : if let Err(err) = Self::background(guard, conf, &tenant, &timeline, remote_client).await {
365 : // Only log as an error if it's not a cancellation.
366 0 : if matches!(err, DeleteTimelineError::Cancelled) {
367 0 : info!("Shutdown during timeline deletion");
368 : }else {
369 0 : error!("Error: {err:#}");
370 : }
371 0 : if let TimelineOrOffloaded::Timeline(timeline) = timeline {
372 0 : timeline.set_broken(format!("{err:#}"))
373 0 : }
374 0 : };
375 0 : Ok(())
376 0 : }
377 0 : .instrument(tracing::info_span!(parent: None, "delete_timeline", tenant_id=%tenant_shard_id.tenant_id, shard_id=%tenant_shard_id.shard_slug(),timeline_id=%timeline_id)),
378 : );
379 0 : }
380 :
381 0 : async fn background(
382 0 : mut guard: DeletionGuard,
383 0 : conf: &PageServerConf,
384 0 : tenant: &Tenant,
385 0 : timeline: &TimelineOrOffloaded,
386 0 : remote_client: Arc<RemoteTimelineClient>,
387 0 : ) -> Result<(), DeleteTimelineError> {
388 0 : fail::fail_point!("timeline-delete-before-rm", |_| {
389 0 : Err(anyhow::anyhow!("failpoint: timeline-delete-before-rm"))?
390 0 : });
391 :
392 : // Offloaded timelines have no local state
393 : // TODO: once we persist offloaded information, delete the timeline from there, too
394 0 : if let TimelineOrOffloaded::Timeline(timeline) = timeline {
395 0 : delete_local_timeline_directory(conf, tenant.tenant_shard_id, timeline).await;
396 0 : }
397 :
398 0 : fail::fail_point!("timeline-delete-after-rm", |_| {
399 0 : Err(anyhow::anyhow!("failpoint: timeline-delete-after-rm"))?
400 0 : });
401 :
402 0 : remote_client.delete_all().await?;
403 :
404 0 : pausable_failpoint!("in_progress_delete");
405 :
406 0 : remove_maybe_offloaded_timeline_from_tenant(tenant, timeline, &guard).await?;
407 :
408 : // This is susceptible to race conditions, i.e. we won't continue deletions if there is a crash
409 : // between the deletion of the index-part.json and reaching of this code.
410 : // So indeed, the tenant manifest might refer to an offloaded timeline which has already been deleted.
411 : // However, we handle this case in tenant loading code so the next time we attach, the issue is
412 : // resolved.
413 0 : tenant.store_tenant_manifest().await.map_err(|e| match e {
414 0 : TenantManifestError::Cancelled => DeleteTimelineError::Cancelled,
415 0 : _ => DeleteTimelineError::Other(e.into()),
416 0 : })?;
417 :
418 0 : *guard = Self::Finished;
419 0 :
420 0 : Ok(())
421 0 : }
422 :
423 0 : pub(crate) fn is_not_started(&self) -> bool {
424 0 : matches!(self, Self::NotStarted)
425 0 : }
426 : }
427 :
428 : #[derive(Copy, Clone, PartialEq, Eq)]
429 : pub(super) enum TimelineDeleteGuardKind {
430 : Offload,
431 : Delete,
432 : }
433 :
434 4 : pub(super) fn make_timeline_delete_guard(
435 4 : tenant: &Tenant,
436 4 : timeline_id: TimelineId,
437 4 : guard_kind: TimelineDeleteGuardKind,
438 4 : ) -> Result<(TimelineOrOffloaded, DeletionGuard), DeleteTimelineError> {
439 4 : // Note the interaction between this guard and deletion guard.
440 4 : // Here we attempt to lock deletion guard when we're holding a lock on timelines.
441 4 : // This is important because when you take into account `remove_timeline_from_tenant`
442 4 : // we remove timeline from memory when we still hold the deletion guard.
443 4 : // So here when timeline deletion is finished timeline wont be present in timelines map at all
444 4 : // which makes the following sequence impossible:
445 4 : // T1: get preempted right before the try_lock on `Timeline::delete_progress`
446 4 : // T2: do a full deletion, acquire and drop `Timeline::delete_progress`
447 4 : // T1: acquire deletion lock, do another `DeleteTimelineFlow::run`
448 4 : // For more context see this discussion: `https://github.com/neondatabase/neon/pull/4552#discussion_r1253437346`
449 4 : let timelines = tenant.timelines.lock().unwrap();
450 4 : let timelines_offloaded = tenant.timelines_offloaded.lock().unwrap();
451 :
452 4 : let timeline = match timelines.get(&timeline_id) {
453 4 : Some(t) => TimelineOrOffloaded::Timeline(Arc::clone(t)),
454 0 : None => match timelines_offloaded.get(&timeline_id) {
455 0 : Some(t) => TimelineOrOffloaded::Offloaded(Arc::clone(t)),
456 0 : None => return Err(DeleteTimelineError::NotFound),
457 : },
458 : };
459 :
460 : // Ensure that there are no child timelines, because we are about to remove files,
461 : // which will break child branches
462 4 : let mut children = Vec::new();
463 4 : if guard_kind == TimelineDeleteGuardKind::Delete {
464 0 : children.extend(timelines_offloaded.iter().filter_map(|(id, entry)| {
465 0 : (entry.ancestor_timeline_id == Some(timeline_id)).then_some(*id)
466 0 : }));
467 4 : }
468 8 : children.extend(timelines.iter().filter_map(|(id, entry)| {
469 8 : (entry.get_ancestor_timeline_id() == Some(timeline_id)).then_some(*id)
470 8 : }));
471 4 :
472 4 : if !children.is_empty() {
473 0 : return Err(DeleteTimelineError::HasChildren(children));
474 4 : }
475 4 :
476 4 : // Note that using try_lock here is important to avoid a deadlock.
477 4 : // Here we take lock on timelines and then the deletion guard.
478 4 : // At the end of the operation we're holding the guard and need to lock timelines map
479 4 : // to remove the timeline from it.
480 4 : // Always if you have two locks that are taken in different order this can result in a deadlock.
481 4 :
482 4 : let delete_progress = Arc::clone(timeline.delete_progress());
483 4 : let delete_lock_guard = match delete_progress.try_lock_owned() {
484 4 : Ok(guard) => DeletionGuard(guard),
485 : Err(_) => {
486 : // Unfortunately if lock fails arc is consumed.
487 0 : return Err(DeleteTimelineError::AlreadyInProgress(Arc::clone(
488 0 : timeline.delete_progress(),
489 0 : )));
490 : }
491 : };
492 :
493 4 : if guard_kind == TimelineDeleteGuardKind::Delete {
494 0 : if let TimelineOrOffloaded::Timeline(timeline) = &timeline {
495 0 : timeline.set_state(TimelineState::Stopping);
496 0 : }
497 4 : }
498 :
499 4 : Ok((timeline, delete_lock_guard))
500 4 : }
501 :
502 : pub(super) struct DeletionGuard(OwnedMutexGuard<DeleteTimelineFlow>);
503 :
504 : impl Deref for DeletionGuard {
505 : type Target = DeleteTimelineFlow;
506 :
507 0 : fn deref(&self) -> &Self::Target {
508 0 : &self.0
509 0 : }
510 : }
511 :
512 : impl DerefMut for DeletionGuard {
513 0 : fn deref_mut(&mut self) -> &mut Self::Target {
514 0 : &mut self.0
515 0 : }
516 : }
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