[U-Boot] UBIFS fails on SheevaPlug

[Vikram Narayanan <vikram186@gmail.com>]

On 10/29/2012 10:55 PM, Dimax wrote:
> I remember I have unbricked sheevaplug with USB key.
> But I'm still not sure if effort is not useless as I see no conclusion
> about u-boot ability to recover UBIFS partition (at least to try).
> Can anybody tell it for sure?

This is what I've got from the code [1].

Code flow
---------
common/cmd_ubifs.c:
do_ubifs_mount calls ubifs_mount 

fs/ubifs/super.c,
In ubifs_mount()  (line 1167)
	flags = MS_RDONLY;	(line 1188)
calls ubifs_get_sb (with flags as a param)
ubifs_get_sb (line 1018)
The flags get updated here.
	sb->s_flags = flags; (line 1057)

Calls ubifs_fill_super
sb gets assigned, so are the flags.
	c->vfs_sb = sb; (line 962)

Calls mount_ubifs
	mount_ubifs(c); (line 983)

In mount_ubifs() (line 582)

	struct super_block *sb = c->vfs_sb;
	int err, mounted_read_only = (sb->s_flags & MS_RDONLY);

sb taken from the assigned ptr @ line 962.
Flags extracted from the assigned flags @ 1188.
Just see where the variable 'mounter_read_only' gets referred and you'll get the answer.
U-boot will _not_ recover your UBIFS partition like the Linux kernel. CMIIW.

[1] http://git.denx.de/?p=u-boot.git;a=tree;h=5bb3505fa867ded03cbee83f7722ab5182930637;hb=5bb3505fa867ded03cbee83f7722ab5182930637

Hope this helps,
Vikram