On Thu, 2010-03-25 at 13:47 -0400, J. Bruce Fields wrote: > On Mon, Mar 22, 2010 at 04:33:40PM -0400, Jeff Layton wrote: > > It looks like nfs_inode_return_delegation always calls nfs_msync_inode > > on any valid delegation before returning it, regardless of the > > delegation type. > > > > RFC 3530 says this: > > > > If the client is granted a read delegation, it is assured that no > > other client has the ability to write to the file for the duration of > > the delegation. If the client is granted a write delegation, the > > client is assured that no other client has read or write access to > > the file. > > > > That doesn't seem to imply that we must flush writes before returning > > either type of delegation. OTOH, maybe it makes sense to treat those as > > cache consistency points since a delegreturn sort of implies that > > another client wants to use the file. > > > > I'm not quite sure how to interpret the spec here... > > If there's that call could cause the client to wait for an actual write > to succeed before returning the delegation, then something's wrong. We're certainly expected to write back data before returning a write delegation (see Section 9.4.4 of RFC 3530). For the case of a read delegation, then the spec is silent because it contains no discussion of the case where a server grants both an open for write and a read delegation. If you want a normative statement on what clients should do for that case, then I suggest a discussion on the IETF list with a view to getting it into RFC3530-bis. Trond -- 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
