No "Erase at 0x.. " or other message when mount !

When after I mount jffs2: " mount jffs2 /dev/mtdblock0 /mnt " there is no message such as "Erase at 0x003d0000" or "jffs2_scan_eraseblock(): Magic bitmask 0x1985 not found at 0x003f0000: 0x0100 instead" . I copy some dirs and files to the dir /mnt and after power off and start uclinuc these files and dirs also in it. Is the hints tell me mount jffs2 successful?? And the messages "Erase at 0x003d0000" and "jffs2_scan_eraseblock(): Magic bitmask 0x1985 not found at 0x003f0000: 0x0100 instead" explain about what ? Please help me and explain it everyone. Thanks very much!