Messages in this thread | | | Date | Sat, 17 May 2003 17:06:13 +0100 | From | Christoph Hellwig <> | Subject | Re: [RFC][PATCH] vm_operation to avoid pagefault/inval race |
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On Tue, May 13, 2003 at 01:53:26PM -0700, Paul E. McKenney wrote: > This patch adds a vm_operations_struct function pointer that allows > networked and distributed filesystems to avoid a race between a > pagefault on an mmap and an invalidation request from some other > node. The race goes as follows:
The race is real although currenly no in-tree filesystem is affected. The patch is uglyh as hell, though. The right fix is to change the ->nopage method to cover what do_no_page is currently, change anonymous vmas to have vm_ops as well and set ->nopage to do_anonymous_page.
The gets of the current do_no_page become a new helper (__finish_nopage?) and EXPORT_SYMBOL_GPL()ed. It would also be nice if you could point to a filesystem that actually needs this, but if you can get rid of the do_anonymous_page special casing a patch might even be acceptable without it.
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