sqlite: set busy timeout to 100s

Only one process can write to the sqlite db at the same time, if another
process tries to use it at that time it fails and a database is locked
error is returned. If this happens sqlite should keep retrying until it
can write. To do that we can just set the _busy_timeout option. A 100s
timeout should be enough even on slower systems but not to much in case
there is a deadlock so it still returns in a reasonable time.

[NO NEW TESTS NEEDED] I think we strongly need to consider some form of
parallel stress testing to catch bugs like this.

Fixes containers#20809

Signed-off-by: Paul Holzinger <[email protected]>

libpod/sqlite_state.go

@@ -40,13 +40,17 @@ const (
 	sqliteOptionForeignKeys = "&_foreign_keys=1"
 	// Make sure that transactions happen exclusively.
 	sqliteOptionTXLock = "&_txlock=exclusive"
+	// Make sure busy timeout is set to high value to keep retying when the db is locked.
+	// Timeout is in ms, so set it to 100s to have enough time to retry the operations.
+	sqliteOptionBusyTimeout = "&_busy_timeout=100000"
 
 	// Assembled sqlite options used when opening the database.
 	sqliteOptions = "db.sql?" +
 		sqliteOptionLocation +
 		sqliteOptionSynchronous +
 		sqliteOptionForeignKeys +
-		sqliteOptionTXLock
+		sqliteOptionTXLock +
+		sqliteOptionBusyTimeout
 )
 
 // NewSqliteState creates a new SQLite-backed state database.