On Sun, Jan 22, 2017 at 06:19:24PM +0000, Matthew Wilcox wrote:
No, I mean a network filesystem like 9p or cifs or nfs. If the
is supposed to be performed by the backing device
struct backing_dev has no relation to the DAX code. Even more so what's
the point of doing a DAXish memcpy in that case? If we buffer in
memory for network I/O we should just use the page cache.
(Also, the network filesystem might have a command, like RDMA
has/will have, to ensure that the write has reached persistence)
I know very well due to my work for a DAX-backed pNFS layout. But that
is mostly transparent to the NFS frontend code and won't use DAX
on the client at all. Just pagecache as a source for RDMA READ/WRITE.