lkml@looxix.net wrote:
>>Luc Van Oostenryck wrote:
> 
> 
> <snip>
> 
>>Yes, there seems to be something missing.
>>
>>The others fs use something like a mix of calling vmtruncate() and/or
>>something like the code below,
>>either in setattr() or XXX_truncate() (to add in inode_operations and
>>called by vmtruncate if present)
>>
>>	page = grab_cache_page(inode->i_mapping, inode->i_size >>
>>PAGE_CACHE_SHIFT) // or attrs->ia_size  >> PAGE_CACHE_SHIFT
>>	// if needed, fill with zeroes the partial page
>>	// there is already a/some function to do this
>>	flush_dcache_page(page);
>>	unlock_page(page);
>>	page_cache_release(page);
>>
> 
> 
> Forget about this for the moment.
> vmtruncate() is called via inode_settattr() which is done at the and of
> yaffs_setattr()
> And vmtruncate()can call a method "truncate" if implemented
> This method doesn't seems to be needed for the way we actually do the
> truncation/resizing.
> 
> 
>>I will need to investigate much further.
>>
> 
> 
> I hadn't enough time yesterday, but there is something that I don't
> understand: in yaffs_setattr() -> yaffs_SetAttributes() ->
> yaffs_ResizeFile(), how the object filesize is changed if newSize >
> oldFileSize ?
>>From what I understand, it this never changed.

OK, I found it.
It is changed by the yaffs_writepage() called by vmtruncate(),
but there is a bug there when we are extending the file.

The problem was detected whe traces in yaffs_writepage() reported the following:
	yaffs_writepage at 0001d000, size 000001d8
	writepag0: obj = 0e1d8, ino = 0e1d8
	                 ^^^^^
	Chunk -1 not found zero instead
	writepag1: obj = 1d1d8, ino = 0e1d8
	                 ^^^^^

I need to check if there is not similar corner case, but the attached patch
seems to indeed solve the problems, at least the test is runnig well now.

> Apart this, I think that in the case of a resizing down, the object header
> can be updated several times: once in yaffs_ResizeFile and once in
> yaffs_SetAttributes.
> 


Luc