Hello
This error message say your underlying filesystem returned less bytes than it should be. Usually this means storage was
corruptedand should be checked by sysadmins.
https://github.com/postgres/postgres/blob/REL_10_STABLE/src/backend/storage/smgr/md.c#L776
So i suggest shutdown database, then copy full PGDATA directory, check disks and filesystem and recover database from
backup.Or you may try enable zero_damaged_pages (this removes your data in such pages!) and copy the surviving data
(betterhaving another copy PGDATA).
regards, Sergei