Re: [PATCH 1/5]: ufs: missed brelse and wrong baseblk

[Evgeniy Dushistov <dushistov@mail.ru>]

On Mon, Jun 19, 2006 at 07:28:33PM +0100, Al Viro wrote:
> But now we have the buffer_heads on page 0 in the state inconsistent with
> the reality - basically, fs/buffer.c helpers will assume that they are
> _still_ in the second state (known to be in hole), while in the reality
> they should be either in the first or in the third one (mapped to known
> disk block or not known).
> 
> It's not a fundamental problem; 
And if we'll write after that to 0th page,
data with size <=page size, we can get garbage(not zeroes) 
on the rest of page.

Definitely, after block allocation, 
we should touch pages from inode cache,
which belongs to block except current page.

>however, it does mean that using these
> helpers means using library functions in situation they'd never been designed
> for.  IOW, you need very careful analysis of the assumptions made by
> the entire bunch and, quite possibly, need versions modified for UFS.
May be there is some incomprehension here,
this series and all other my patches in -mm related to UFS
is not introduced write support for UFS, they fixes
bugs similar to which you point out in black corners 
of the existing implementation.

Note: almost all such bugs related to 
touch blockdev's cache instead of inode's cache, and working
with blockdev's buffer cache without take into consideration
that it's also page cache).

-- 
/Evgeniy

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