Christian Schwarz 5be8d38a63 fix deadlock around TENANTS (#5285) ...

The sequence that can lead to a deadlock:

1. DELETE request gets all the way to `tenant.shutdown(progress,
false).await.is_err() ` , while holding TENANTS.read()
2. POST request for tenant creation comes in, calls `tenant_map_insert`,
it does `let mut guard = TENANTS.write().await;`
3. Something that `tenant.shutdown()` needs to wait for needs a
`TENANTS.read().await`.
The only case identified in exhaustive manual scanning of the code base
is this one:
Imitate size access does `get_tenant().await`, which does
`TENANTS.read().await` under the hood.

In the above case (1) waits for (3), (3)'s read-lock request is queued
behind (2)'s write-lock, and (2) waits for (1).
Deadlock.

I made a reproducer/proof-that-above-hypothesis-holds in
https://github.com/neondatabase/neon/pull/5281 , but, it's not ready for
merge yet and we want the fix _now_.

fixes https://github.com/neondatabase/neon/issues/5284

2023-09-12 11:23:46 +02:00

..

benches

refactor: remove is_incremental=true for ImageLayers footgun (#5061)

2023-08-22 22:12:05 +03:00

ctl

Make VirtualFile::{open, open_with_options, create,sync_all,with_file} async fn (#5224)

2023-09-08 00:50:50 +02:00

fixtures

walredo: simple tests and bench updates (#3045)

2023-01-16 18:24:45 +02:00

src

fix deadlock around TENANTS (#5285)

2023-09-12 11:23:46 +02:00

Cargo.toml

Make EphemeralFile::write_blob function async (#5056)

2023-08-24 19:18:30 +02:00