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

[Al Viro]

On Mon, Jun 19, 2006 at 10:58:16PM +0400, Evgeniy Dushistov wrote:
> On Mon, Jun 19, 2006 at 07:28:33PM +0100, Al Viro wrote:
> > On Mon, Jun 19, 2006 at 05:17:50PM +0400, Evgeniy Dushistov wrote:
> > > In case of 1k fragments, msync of two pages
> > > cause 8 calls of ufs's get_block_t with create == 1,
> > > they will be consequent because of synchronization.
> > 
> > _What_ synchronization?
> > Now, which lock would, in your opinion, provide serialization between these
> > two calls?  They apply to different pages, so page locks do not help.
> >  
> you can look at fs/ufs/inode.c: ufs_getfrag_block.
> It is ufs's get_block_t,
> if create == 1 it uses "[un]lock_kernel". 

Which is fsck-all protection, since then you proceed to do a lot of
blocking operations.  Now, lock_super() down in balloc.c _might_ be
enough, but I wouldn't bet on that.
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