On Mon, May 21, 2007 at 08:11:42PM +1000, David Chinner wrote: > Christoph - this is an interaction with xfs_buf_associate_memory(); > I'm not sure what it is doing is at all safe now that it never gets > passed kmem_alloc()d memory - it works for the log recovery case > because we use it in pairs - once to shorten the buffer and then once > to put it back the way it was. > > But that doesn't work for the log buffers (we never return them to their > original state) and the log wrap case looks to work mostly by accident > now (and could posibly lead to double freeing pages).... > > It seems that what we really need with the new code is a xfs_buf_clone() > operation followed by trimming the range to what the secondary I/O needs > to span. This would work for the log buffer case as well. Your thoughts?
xfs_buf_associate_memory is a mess. My original plan was to get rid of it, but I kept that out to keep that patchset small and easily reviable, but it seems like that was a mistake. My plan is the following: - xlog_bread and thus the whole buffer I/O path grows an iooffset paramater that specifies at which offset into the buffer we start the actual I/O. That gets rid of all the xfs_buf_associate_memory memory uses in the log recovery code - add a buffer clone operation as suggested by you above, and use the offset in xlog_sync aswell. until then you patch below looks fine. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
