It is normal that svn db get crashed because of permission issue. The following steps help to fix it.
chown svnuser:svngroup /path/to/repos
find /path/to/repos -type d -print0 -exec chmod 2775 {} \;
find /path/to/repos -type f -print0 -exec chmod 0664 {} \;
svnadmin recover /path/to/repos