How to correctly understand the error when executing pg_dump?

Question

linux

I can't figure out how to solve the problem, I do:
[email protected]:/usr/bin$ pg_dump -s -U postgres TEST > /home/postgres/backup/TEST.SQL.GZ
falls to syslog:
pg_dump: Dumping the contents of table " _document10346_vt10355" failed: PQgetResult() failed.
pg_dump: Error message from server: ERROR: could not read block 1203960 in file "base/66124420/66126205.9": read only 0 of 8192
bytes ) TO stdout;
Tell me how to solve?