On Mon, 15 Oct 2007, Pekka Enberg wrote:
quoted text
> 
> I wonder whether _not setting_ BDI_CAP_NO_WRITEBACK implies that
> ->writepage() will never return AOP_WRITEPAGE_ACTIVATE for
> !wbc->for_reclaim case which would explain why we haven't hit this bug
> before. Hugh, Andrew?

Only ramdisk and shmem have been returning AOP_WRITEPAGE_ACTIVATE.
Both of those set BDI_CAP_NO_WRITEBACK.  ramdisk never returned it
if !wbc->for_reclaim.  I contend that shmem shouldn't either: it's
a special code to get the LRU rotation right, not useful elsewhere.
Though Documentation/filesystems/vfs.txt does imply wider use.

I think this is where people use the phrase "go figure" ;)

Hugh
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