On Jul 22, 2009, at 4:20 PM, Trond Myklebust wrote:
On Wed, 2009-07-22 at 15:49 -0400, Andy Adamson wrote:
On Jul 21, 2009, at 5:17 PM, Trond Myklebust wrote:
Note that there is a bug remaining inside nfs4_init_session(): we
shouldn't be copying the rsize/wsize into the nfs_client if the
latter
was already initialised.
The rsize/wsize is copied into the session prior to the
create_session
call (triggered by the state management code you moved), and is used
for session negotiation. At this point the nfs_client cl_cons_state
is
set to NFS_CS_SESSION_INITING (see nfs4_alloc_session), so the
nfs_client is not initialized. The cl_cons_state is set to
NFS_CS_READY after a successful create_session call.
The call to nfs4_init_session() is in nfs4_create_server(). It can be
called several times _after_ the nfs_client has been initialised when
you mount more than one partition from the same NFS server.
If that is the case, and if you use different rsize/wsize values on
those different mounts, then you will end up clobbering the values of
fc_attrs.max_rqst_sz, and fc_attrs.max_resp_sz, having set them to the
wsize/rsize that was set by the very last mount call.
You are right, this is a bug.
AFAICS, what you _should_ be doing in nfs4_init_session, is something
like
if (clp->cl_session->fc_attrs.max_rqst_sz < server->wsize)
clp->cl_session->fc_attrs.max_rqst_sz = server->wsize;
Currently, we only support one session per nfs_client - one session
for all partition mounts to the same NFS server.
For NFSv4.1 the per partition struct nfs_server rsize/wsize is used to
construct rpc requests that are sent over the session so the rsize/
wsize must not be larger than the session max_resp_sz/max_rqst_sz.
nfs4_init_session should simply return if the nfs_client cl_cons_state
is not NFS_CS_SESSION_INITING.
I shouldn't be trying to set the session max_resp_sz/max_rqst_sz to
the rsize/wsize, but rather to the maximum rsize/wsize supported by
the client.
If the server accepts or increases the max_resp_sz/max_rqst_sz then
all is well.
If the server reduces the max_resp_sz/max_rqst_sz, the maximum rsize/
wsize available for NFSv4.1 partition mounts to the server needs to be
reduced accordingly. So the nfs_server rsize/wsize needs to be bound
by the session max_resp_sz/max_rqst_sz as well as by the maximum
supported size.
If you think this is correct, I'll send a patch.
-->Andy
Trond
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