Re: [patch] [possible race in ext2] Re: how to write get_block?

Ingo Molnar (mingo@chiara.csoma.elte.hu)
Sun, 10 Oct 1999 13:25:45 +0200 (CEST)


On Sat, 9 Oct 1999, Andrea Arcangeli wrote:

> The current design bug in 2.3.20pre2 and previous has nothing to do with
> bforget.
>
> The right fix is to do a query on the hash every time you overlap a buffer
> on the page cache. [...]

this kind of kludge was in there originally - and it got removed to give
place for a better solution (like what Alexander Viro suggested).

> [...] If you'll find the buffer - you are going to overlap in
> the page-cache - in the hash, then you'll have to flush it exactly as
> flushpage does. My way has no cache coherency downside and it's completly
> safe. It will impact a bit the CPU though. Still far better than 2.2.x

i dont understand what you mean - the hash table lookup stuff was in there
originally, or are you suggesting something else?

> because the hash will be almost empty in 2.3.x compared with the huge one
> of 2.2.x. I just had to do something like that to fix the ramdisk device.
> Now I'll implement the thing.

it was left in such a state for a reason - to get the right fix. Please
dont spend time on putting back old stuff. The 2.3 kernels are development
kernels.

-- mingo

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