From 6ff8da088766d70f0441feb982b82978a6cbf7ef Mon Sep 17 00:00:00 2001 From: "J. Bruce Fields" Date: Fri, 4 Jun 2010 20:04:45 -0400 Subject: nfsd4: Move callback setup to callback queue Instead of creating the new rpc client from a regular server thread, set a flag, kick off a null call, and allow the null call to do the work of setting up the client on the callback workqueue. Use a spinlock to ensure the callback work gets a consistent view of the callback parameters. This allows, for example, changing the callback from contexts where sleeping is not allowed. I hope it will also keep the locking simple as we add more session and trunking features, by serializing most of the callback-specific work. This also closes a small race where the the new cb_ident could be used with an old connection (or vice-versa). Signed-off-by: J. Bruce Fields --- fs/nfsd/nfs4callback.c | 73 +++++++++++++++++++++++++++++++++++--------------- 1 file changed, 52 insertions(+), 21 deletions(-) (limited to 'fs/nfsd/nfs4callback.c') diff --git a/fs/nfsd/nfs4callback.c b/fs/nfsd/nfs4callback.c index 07c3be6eea6..a269dbeff15 100644 --- a/fs/nfsd/nfs4callback.c +++ b/fs/nfsd/nfs4callback.c @@ -284,7 +284,7 @@ nfs4_xdr_enc_cb_recall(struct rpc_rqst *req, __be32 *p, struct xdr_stream xdr; struct nfs4_delegation *args = cb->cb_op; struct nfs4_cb_compound_hdr hdr = { - .ident = args->dl_ident, + .ident = cb->cb_clp->cl_cb_ident, .minorversion = cb->cb_minorversion, }; @@ -506,7 +506,8 @@ int setup_callback_client(struct nfs4_client *clp, struct nfs4_cb_conn *conn) PTR_ERR(client)); return PTR_ERR(client); } - nfsd4_set_callback_client(clp, client); + clp->cl_cb_ident = conn->cb_ident; + clp->cl_cb_client = client; return 0; } @@ -569,15 +570,12 @@ void do_probe_callback(struct nfs4_client *clp) */ void nfsd4_probe_callback(struct nfs4_client *clp, struct nfs4_cb_conn *conn) { - int status; - BUG_ON(atomic_read(&clp->cl_cb_set)); - status = setup_callback_client(clp, conn); - if (status) { - warn_no_callback_path(clp, status); - return; - } + spin_lock(&clp->cl_lock); + memcpy(&clp->cl_cb_conn, conn, sizeof(struct nfs4_cb_conn)); + set_bit(NFSD4_CLIENT_CB_UPDATE, &clp->cl_cb_flags); + spin_unlock(&clp->cl_lock); do_probe_callback(clp); } @@ -730,19 +728,16 @@ void nfsd4_destroy_callback_queue(void) } /* must be called under the state lock */ -void nfsd4_set_callback_client(struct nfs4_client *clp, struct rpc_clnt *new) +void nfsd4_shutdown_callback(struct nfs4_client *clp) { - struct rpc_clnt *old = clp->cl_cb_client; - - clp->cl_cb_client = new; + set_bit(NFSD4_CLIENT_KILL, &clp->cl_cb_flags); /* - * After this, any work that saw the old value of cl_cb_client will - * be gone: + * Note this won't actually result in a null callback; + * instead, nfsd4_do_callback_rpc() will detect the killed + * client, destroy the rpc client, and stop: */ + do_probe_callback(clp); flush_workqueue(callback_wq); - /* So we can safely shut it down: */ - if (old) - rpc_shutdown_client(old); } void nfsd4_release_cb(struct nfsd4_callback *cb) @@ -751,15 +746,51 @@ void nfsd4_release_cb(struct nfsd4_callback *cb) cb->cb_ops->rpc_release(cb); } +void nfsd4_process_cb_update(struct nfsd4_callback *cb) +{ + struct nfs4_cb_conn conn; + struct nfs4_client *clp = cb->cb_clp; + int err; + + /* + * This is either an update, or the client dying; in either case, + * kill the old client: + */ + if (clp->cl_cb_client) { + rpc_shutdown_client(clp->cl_cb_client); + clp->cl_cb_client = NULL; + } + if (test_bit(NFSD4_CLIENT_KILL, &clp->cl_cb_flags)) + return; + spin_lock(&clp->cl_lock); + /* + * Only serialized callback code is allowed to clear these + * flags; main nfsd code can only set them: + */ + BUG_ON(!clp->cl_cb_flags); + clear_bit(NFSD4_CLIENT_CB_UPDATE, &clp->cl_cb_flags); + memcpy(&conn, &cb->cb_clp->cl_cb_conn, sizeof(struct nfs4_cb_conn)); + spin_unlock(&clp->cl_lock); + + err = setup_callback_client(clp, &conn); + if (err) + warn_no_callback_path(clp, err); +} + void nfsd4_do_callback_rpc(struct work_struct *w) { struct nfsd4_callback *cb = container_of(w, struct nfsd4_callback, cb_work); struct nfs4_client *clp = cb->cb_clp; - struct rpc_clnt *clnt = clp->cl_cb_client; + struct rpc_clnt *clnt; - if (clnt == NULL) { + if (clp->cl_cb_flags) + nfsd4_process_cb_update(cb); + + clnt = clp->cl_cb_client; + if (!clnt) { + /* Callback channel broken, or client killed; give up: */ nfsd4_release_cb(cb); - return; /* Client is shutting down; give up. */ + return; } rpc_call_async(clnt, &cb->cb_msg, RPC_TASK_SOFT | RPC_TASK_SOFTCONN, cb->cb_ops, cb); -- cgit v1.2.3