UBIFS remounted ro during operation or from boot time

[Thomas Kaufmann]

Hi

we are using MTD / UBIFS on beaglebone based embedded device with linux.
Sometimes there is a problem with the ubifs root partition, where I am not certain about the root cause.
Details regarding our system:

CPU: ARMv7 Processor [413fc082] revision 2 (ARMv7), cr=10c53c7d
CPU: PIPT / VIPT nonaliasing data cache, VIPT aliasing instruction cache
NAND device: Manufacturer ID: 0x2c, Chip ID: 0x38 (Micron MT29F8G08ABABAWP)

Linux kernel version is 3.2.0, compiled with gcc 4.5.3

It happens that the root partition is being remounted read only during operation. Sometimes also from boot up.
In the dmesg I find this printout:

[   12.224090] UBIFS: recovery needed
[   12.800018] UBIFS: recovery completed
[   12.803894] UBIFS: mounted UBI device 0, volume 0, name "rootfs"
[   12.810180] UBIFS: file system size:   407715840 bytes (398160 KiB, 388 MiB, 790 LEBs)
[   12.818420] UBIFS: journal size:       10452992 bytes (10208 KiB, 9 MiB, 21 LEBs)
[   12.826232] UBIFS: media format:       w4/r0 (latest is w4/r0)
[   12.832336] UBIFS: default compressor: lzo
[   12.836578] UBIFS: reserved for root:  0 bytes (0 KiB)
[   12.844970] VFS: Mounted root (ubifs filesystem) on device 0:13.

[   18.899841] UBIFS error (pid 1800): ubifs_check_node: bad CRC: calculated 0xc6fd2232, read 0xef37a8c0
[   18.909515] UBIFS error (pid 1800): ubifs_check_node: bad node at LEB 486:200480
[   18.917205] UBIFS error (pid 1800): ubifs_scanned_corruption: corruption at LEB 486:200480
<then I think it prints the LEB>
[   18.932037] UBIFS error (pid 1800): ubifs_scan: LEB 486 scanning failed
[   18.939056] UBIFS warning (pid 1800): ubifs_ro_mode: switched to read-only mode, error -117
<more kernel traces>
[   19.095581] UBIFS error (pid 1800): make_reservation: cannot reserve 83 bytes in jhead 2, error -117
[   19.105102] UBIFS error (pid 1800): do_writepage: cannot write page 0 of inode 10754, error -117

This is when the issue is present at bootup.
Sometimes this issue can be resolved by rebooting, but not always.

Is this happening due to a corrupted or defective flash (hardware problem)?
Or is there a known problem in the software versions we are using?

If required I will supply more information about our system.

thanks for any advice or hints towards a root cause
kind regards

Thomas