Re: [PATCH] Useless inode semaphore locking in 2.4.0-test8

From: Andi Kleen (ak@suse.de)
Date: Tue Sep 19 2000 - 05:47:59 EST


On Tue, Sep 19, 2000 at 06:45:43AM -0400, Alexander Viro wrote:
>
>
> On Tue, 19 Sep 2000, Stephen C. Tweedie wrote:
>
> > > ?
> > > I'm afraid that I've lost you here - what do you mean?
> >
> > loop does a bmap() and then submits block IO. You don't want
> > truncate() to revoke blocks in between the bmap and the IO completion.
>
> It used to do bmap(), but unless somebody restored that bogosity it
> shouldn't do that anymore. It gets page, locks it, does prepare_write(),
> copies the data, does commit_write() and unlocks the page - same as
> generic_file_write(). So that shouldn't be a problem - truncate would have
> to wait until the page gets unlocked.

The new async loop device I'm playing with requires it again.

-Andi
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