On Tue, Mar 19, 2013 at 10:28 PM, Fred Isaman <faisaman4@xxxxxxxxx> wrote: > On Tue, Mar 19, 2013 at 3:35 PM, Benny Halevy <bhalevy@xxxxxxxxxx> wrote: >> On 2013-03-18 19:04, Fred Isaman wrote: >>> A problem case is if the layout ends within the page request, which >>> can happen due to the misalignment. >> >> First, the file layout currently supports only whole file layouts so I don't see >> how that's a problem. >> Regardless, I'd rather trim the layout segment to PAGE_SIZE boundaries >> and get a new layout from the page aligned offset and on with minlength = PAGE_SIZE >> (as we do today). >> >> Benny >> > > Yes, but consider.... > > let P = PAGE_SIZE > > assume you have a layout from 0 to 4P, and you try to do a WRITE from > 2P to 6P. Now if the buffer is not page aligned, one of the nfs_page > requests will contain the file's logical 4P offset at a random > location within the nfs_page. What happens then? Since we're using one layout segment at a time this should be handled as short I/O doing the remainder with another lseg. > > Fred -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
