Messages in this thread | | | Date | Fri, 19 Nov 2010 10:24:52 -0500 | From | Mark Lord <> | Subject | Re: [PATCH 1/2] fs: Do not dispatch FITRIM through separate super_operation |
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On 10-11-19 09:54 AM, Christoph Hellwig wrote: > On Fri, Nov 19, 2010 at 09:48:12AM -0500, Mark Lord wrote: >> I'm not sure about the issues on "adapting the block layer" ? >> For FITRIM, the blocks being trimmed would be reserved at the fs level, >> before issuing the discard for them. So ordering through the block layer >> shouldn't matter much for it. Does that simplify things? >> >> I see FITRIM just allocating a page to hold the ranges (for the>1 case) >> and passing that page down through the layers to libata (or any other >> LLD that supports>1 ranges). > > Ordering should not be an issue. What were problems when I tried this > before is that we currently assume in the block layer that discard > bios have a valid bi_sector/bi_size, which is already needed e.g. for > the trivial remapping use for partitions and that they don't have > a payload. You'd need to teach various places that discard payloads > may have a payload, which contains multiple ranges that have a > sector/len tuple that needs to be remapped and checked in various > places.
I wonder if this can be treated more like how SG_IO does things? The SG_IO mechanism seems to have no issues passing through stuff like this, so perhaps we could implement something in a similar fashion?
-ml
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