Hi

Barebox barfs if I try to copy a file inside a mounted MMC fat partition.

Steps to reproduce:

1.) Load barebox (configured as internal boot MMC) as a second stage boot
loader from uboot.
2.) Mount MMC fat partition
3.) Try to copy file to the same partition

This results in this nice BUG():

Board: SID1 NOAH
registered netconsole as cs1
noah_read_ccm_regs: CCM CRDR = 00000000
noah_read_ccm_regs: CCM RCSR = 01020820
noah_read_ccm_regs: Booting from WEIM: NOR
imx-esdhc@mci0: registered as mci0
mci@mci0: registered disk0
imx25_devices_init: Adding NOR flash device
cfi_flash@cfi_flash0: cfi flash (id=01000000 vend=000002 manu=000001
devid=00007E extid=002301) at a0000000, size 64MB
imx25_devices_init: Adding initial NOR flash partitions
ehci@ehci0: USB EHCI 1.00
Malloc space: 0x83b00000 -> 0x83efffff (size  4 MB)
Stack space : 0x83af8000 -> 0x83b00000 (size 32 kB)
envfs: wrong magic on /dev/env0
no valid environment found on /dev/env0. Using default environment
running /env/bin/init...

Hit any key to stop autoboot:  5

type update_kernel nor [<imagename>] to update kernel into flash
type update_root nor [<imagename>] to update rootfs into flash

sid1-noah:/ mkdir /mnt
sid1-noah:/ mount /dev/disk0.0 fat /mnt
sid1-noah:/ time cp /mnt/console_image.jffs2 /mnt/console_image.jffs2-backup
BUG: failure at common/block.c:248/block_put()!
BUG!
[<83f347b4>] (unwind_backtrace+0x0/0x8c) from [<83f1bea4>] (panic+0x28/0x3c)
[<83f1bea4>] (panic+0x28/0x3c) from [<83f058a0>] (block_put+0x48/0x8c)
[<83f058a0>] (block_put+0x48/0x8c) from [<83f0598c>]
(block_write+0xa8/0x120)
[<83f0598c>] (block_write+0xa8/0x120) from [<83f2d288>]
(cdev_write+0x30/0x34)
[<83f2d288>] (cdev_write+0x30/0x34) from [<83f30780>] (disk_write+0x24/0x30)
[<83f30780>] (disk_write+0x24/0x30) from [<83f2f8cc>] (f_write+0x160/0x27c)
[<83f2f8cc>] (f_write+0x160/0x27c) from [<83f30540>] (fat_write+0x18/0x30)
[<83f30540>] (fat_write+0x18/0x30) from [<83f31030>] (write+0xac/0xd0)
[<83f31030>] (write+0xac/0xd0) from [<83f21674>] (copy_file+0xec/0x17c)
[<83f21674>] (copy_file+0xec/0x17c) from [<83f18ff0>] (do_cp+0x124/0x158)
[<83f18ff0>] (do_cp+0x124/0x158) from [<83f07b50>]
(execute_command+0x38/0x7c)
[<83f07b50>] (execute_command+0x38/0x7c) from [<83f03b84>]
(run_list_real+0x8a0/0x998)
[<83f03b84>] (run_list_real+0x8a0/0x998) from [<83f03dc0>]
(parse_stream_outer+0x144/0x240)
[<83f03dc0>] (parse_stream_outer+0x144/0x240) from [<83f0327c>]
(parse_string_outer+0x9c/0x104)
[<83f0327c>] (parse_string_outer+0x9c/0x104) from [<83f04164>]
(run_command+0x18/0x30)
[<83f04164>] (run_command+0x18/0x30) from [<83f1aaa4>] (do_time+0x8c/0xf0)
[<83f1aaa4>] (do_time+0x8c/0xf0) from [<83f07b50>]
(execute_command+0x38/0x7c)
[<83f07b50>] (execute_command+0x38/0x7c) from [<83f03b84>]
(run_list_real+0x8a0/0x998)
[<83f03b84>] (run_list_real+0x8a0/0x998) from [<83f03dc0>]
(parse_stream_outer+0x144/0x240)
[<83f03dc0>] (parse_stream_outer+0x144/0x240) from [<83f041b8>]
(run_shell+0x3c/0x5c)
[<83f041b8>] (run_shell+0x3c/0x5c) from [<83f095e0>]
(start_barebox+0xd4/0x110)
[<83f095e0>] (start_barebox+0xd4/0x110) from [<8010206c>] (0x8010206c)

I reckon it might be something I shouldn't be doing, however I thought I
still report it here.

Cheers
Roberto