Re: [PATCH 3/3] block: Introduce blkdev_issue_zeroout_discard() function

[Theodore Ts'o <tytso@mit.edu>]

On Fri, Nov 07, 2014 at 10:42:24AM -0500, Martin K. Petersen wrote:
> >>>>> "Christoph" == Christoph Hellwig <hch@infradead.org> writes:
> 
> Christoph> I'm not a fan of adding another function here and would
> Christoph> prefer a flag, but it looks correct, 
> 
> That was my original approach too but I didn't want to stomp over all
> the existing callers. Although there only are few.
> 
> Ted: Which would you prefer?

There are *very* few users of blkdev_issue_zeroout(), and aside for a
single drbd, they are all in the block layer.  It would only start
affecting ext4 when we plumb that flag through to sb_issue_zeroout
(which your patch doesn't currently do), at which point it will affect
4 call sites in ext4, and a call site in gfs2 and hpfs2.

So I'd be in favor of adding a flag to to blkdev_issue_zeroout(), and
I would have a slight preference for also modifying sb_issue_zeroout
so the flag gets plumbed all the way through to the fs-level callers.

Cheers,

							- Ted