Messages in this thread | | | Date | Mon, 7 Dec 2015 21:28:30 -0800 | From | "Darrick J. Wong" <> | Subject | Re: [PATCH v4] block: create ioctl to discard-or-zeroout a range of blocks |
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On Mon, Dec 07, 2015 at 06:40:15PM -0800, Christoph Hellwig wrote: > On Fri, Nov 13, 2015 at 02:01:43PM -0800, Darrick J. Wong wrote: > > Create a new ioctl to expose the block layer's newfound ability to > > issue either a zeroing discard, a WRITE SAME with a zero page, or a > > regular write with the zero page. This BLKZEROOUT2 ioctl takes > > {start, length, flags} as parameters. So far, the only flag available > > is to enable the zeroing discard part -- without it, the call invokes > > the old BLKZEROOUT behavior. start and length have the same meaning > > as in BLKZEROOUT. > > > > Furthermore, because BLKZEROOUT2 issues commands directly to the > > storage device, we must invalidate the page cache (as a regular > > O_DIRECT write would do) to avoid returning stale cache contents at a > > later time. > > So does BLKZEROOUT. Seems like adding the cache invalidation should > be one patch and the ioctl another one. Otherwise this looks fine > except that I kinda hate BLKZEROOUT2 name, but can't come up with > anything better.
I should've sent the 4.4 version -- since the ioctl code was refactored into separate functions and the new function modifies its arguments, I ended up rewriting most of the function body just to set up the page cache invalidation.
(Ah, I see -- 4.4-rc1 came out and I forgot to resend.)
Blergh, v5 on its way...
--D
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