u-boot bootflow btrfs tracking issue

[nakato]

BTRFS seems to fail to read if a number of bytes to read is provided.

=> load mmc 1:3 ${pxefile_addr_r} /boot/extlinux/extlinux.conf
658 bytes read in 45 ms (13.7 KiB/s)

=> load mmc 1:3 ${pxefile_addr_r} /boot/extlinux/extlinux.conf 658
** /boot/extlinux/extlinux.conf shorter than offset + len **
0 bytes read in 28 ms (0 Bytes/s)

Bootflow responds:

Scanning bootdev 'mmc@ff500000.bootdev':
trying: /boot/extlinux/extlinux.conf
   /boot/extlinux/extlinux.conf - err=0
   - script file size 292
** /boot/extlinux/extlinux.conf shorter than offset + len **

Solving this should get BTRFS booting with bootflow.

[nakato]

   > applying patch /nix/store/2rbvbzyybhhz6g1j7qwx29y14wmnzw1i-uboot.patch
   > patching file fs/btrfs/btrfs.c
   > Hunk #1 FAILED at 252.

I should really debug against head when I hit things like this, fixed 10 weeks ago.

6d6ea52b629c384fb8605678b9003d2a077f9148