Linux fs/JFFS2 question.

Linux-mtd,
I need some help understanding some code under linux-2.6.x/fs/jffs2. After trying to mount a JFFS2 file system, by typing mount mtd:JFFS2 /mnt, without success. I did some digging in the code, and I found if I change a line in linux-2.6.x/fs/jffs2/scan.c mount works! Listed below is the one change I made in function jffs2_scan_medium().

if (!ret && pointlen < c->mtd->size) { OLD code

if (!ret && pointlen <= c->mtd->size) { NEW code

Later in the function the side effect of this if() statement is an altered value for buf_size, not 0. This value is then passed to the function jffs2_scan_eraseblock() where buf_size is tested. Here is where my understanding of things falls apart.

if (!buf_size) {
           /* Do stuff, but do NOT read anything from the flash. */
           ...
} else {
          ...
          jffs2_fill_scan_buf( ...);
}

It appears to me if buf_size is prevented from being set back in
jffs2_scan_medium() then an actual read from the flash does occur, which
allows mount to read valid data and have success. Otherwise there
appears to me that the read never made, creating a guaranteed failure every time.
Why is this the case?
I can't find where or how the driver ever reads real data otherwise.
Help me see the bigger picture here.
I first sent this to uClinux-devel mailing list so I provided the following info to help describe the context in which I am working. uClinux source: uClinux-dist-20060803
tool chain: m68k-uclinux-tools-20060615.sh
processor: COLDFIRE M5272

Looking forward to being enlightened,
Glen Johnson