1 files changed, 502 insertions, 0 deletions

diff --git a/fs/afs/server.c b/fs/afs/server.c
new file mode 100644
index 0000000..62b093a
--- /dev/null
+++ b/fs/afs/server.c
@@ -0,0 +1,502 @@
+/* server.c: AFS server record management
+ *
+ * Copyright (C) 2002 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+
+#include <linux/sched.h>
+#include <linux/slab.h>
+#include <rxrpc/peer.h>
+#include <rxrpc/connection.h>
+#include "volume.h"
+#include "cell.h"
+#include "server.h"
+#include "transport.h"
+#include "vlclient.h"
+#include "kafstimod.h"
+#include "internal.h"
+
+DEFINE_SPINLOCK(afs_server_peer_lock);
+
+#define FS_SERVICE_ID		1	/* AFS Volume Location Service ID */
+#define VL_SERVICE_ID		52	/* AFS Volume Location Service ID */
+
+static void __afs_server_timeout(struct afs_timer *timer)
+{
+	struct afs_server *server =
+		list_entry(timer, struct afs_server, timeout);
+
+	_debug("SERVER TIMEOUT [%p{u=%d}]",
+	       server, atomic_read(&server->usage));
+
+	afs_server_do_timeout(server);
+}
+
+static const struct afs_timer_ops afs_server_timer_ops = {
+	.timed_out	= __afs_server_timeout,
+};
+
+/*****************************************************************************/
+/*
+ * lookup a server record in a cell
+ * - TODO: search the cell's server list
+ */
+int afs_server_lookup(struct afs_cell *cell, const struct in_addr *addr,
+		      struct afs_server **_server)
+{
+	struct afs_server *server, *active, *zombie;
+	int loop;
+
+	_enter("%p,%08x,", cell, ntohl(addr->s_addr));
+
+	/* allocate and initialise a server record */
+	server = kmalloc(sizeof(struct afs_server), GFP_KERNEL);
+	if (!server) {
+		_leave(" = -ENOMEM");
+		return -ENOMEM;
+	}
+
+	memset(server, 0, sizeof(struct afs_server));
+	atomic_set(&server->usage, 1);
+
+	INIT_LIST_HEAD(&server->link);
+	init_rwsem(&server->sem);
+	INIT_LIST_HEAD(&server->fs_callq);
+	spin_lock_init(&server->fs_lock);
+	INIT_LIST_HEAD(&server->cb_promises);
+	spin_lock_init(&server->cb_lock);
+
+	for (loop = 0; loop < AFS_SERVER_CONN_LIST_SIZE; loop++)
+		server->fs_conn_cnt[loop] = 4;
+
+	memcpy(&server->addr, addr, sizeof(struct in_addr));
+	server->addr.s_addr = addr->s_addr;
+
+	afs_timer_init(&server->timeout, &afs_server_timer_ops);
+
+	/* add to the cell */
+	write_lock(&cell->sv_lock);
+
+	/* check the active list */
+	list_for_each_entry(active, &cell->sv_list, link) {
+		if (active->addr.s_addr == addr->s_addr)
+			goto use_active_server;
+	}
+
+	/* check the inactive list */
+	spin_lock(&cell->sv_gylock);
+	list_for_each_entry(zombie, &cell->sv_graveyard, link) {
+		if (zombie->addr.s_addr == addr->s_addr)
+			goto resurrect_server;
+	}
+	spin_unlock(&cell->sv_gylock);
+
+	afs_get_cell(cell);
+	server->cell = cell;
+	list_add_tail(&server->link, &cell->sv_list);
+
+	write_unlock(&cell->sv_lock);
+
+	*_server = server;
+	_leave(" = 0 (%p)", server);
+	return 0;
+
+	/* found a matching active server */
+ use_active_server:
+	_debug("active server");
+	afs_get_server(active);
+	write_unlock(&cell->sv_lock);
+
+	kfree(server);
+
+	*_server = active;
+	_leave(" = 0 (%p)", active);
+	return 0;
+
+	/* found a matching server in the graveyard, so resurrect it and
+	 * dispose of the new record */
+ resurrect_server:
+	_debug("resurrecting server");
+
+	list_del(&zombie->link);
+	list_add_tail(&zombie->link, &cell->sv_list);
+	afs_get_server(zombie);
+	afs_kafstimod_del_timer(&zombie->timeout);
+	spin_unlock(&cell->sv_gylock);
+	write_unlock(&cell->sv_lock);
+
+	kfree(server);
+
+	*_server = zombie;
+	_leave(" = 0 (%p)", zombie);
+	return 0;
+
+} /* end afs_server_lookup() */
+
+/*****************************************************************************/
+/*
+ * destroy a server record
+ * - removes from the cell list
+ */
+void afs_put_server(struct afs_server *server)
+{
+	struct afs_cell *cell;
+
+	if (!server)
+		return;
+
+	_enter("%p", server);
+
+	cell = server->cell;
+
+	/* sanity check */
+	BUG_ON(atomic_read(&server->usage) <= 0);
+
+	/* to prevent a race, the decrement and the dequeue must be effectively
+	 * atomic */
+	write_lock(&cell->sv_lock);
+
+	if (likely(!atomic_dec_and_test(&server->usage))) {
+		write_unlock(&cell->sv_lock);
+		_leave("");
+		return;
+	}
+
+	spin_lock(&cell->sv_gylock);
+	list_del(&server->link);
+	list_add_tail(&server->link, &cell->sv_graveyard);
+
+	/* time out in 10 secs */
+	afs_kafstimod_add_timer(&server->timeout, 10 * HZ);
+
+	spin_unlock(&cell->sv_gylock);
+	write_unlock(&cell->sv_lock);
+
+	_leave(" [killed]");
+} /* end afs_put_server() */
+
+/*****************************************************************************/
+/*
+ * timeout server record
+ * - removes from the cell's graveyard if the usage count is zero
+ */
+void afs_server_do_timeout(struct afs_server *server)
+{
+	struct rxrpc_peer *peer;
+	struct afs_cell *cell;
+	int loop;
+
+	_enter("%p", server);
+
+	cell = server->cell;
+
+	BUG_ON(atomic_read(&server->usage) < 0);
+
+	/* remove from graveyard if still dead */
+	spin_lock(&cell->vl_gylock);
+	if (atomic_read(&server->usage) == 0)
+		list_del_init(&server->link);
+	else
+		server = NULL;
+	spin_unlock(&cell->vl_gylock);
+
+	if (!server) {
+		_leave("");
+		return; /* resurrected */
+	}
+
+	/* we can now destroy it properly */
+	afs_put_cell(cell);
+
+	/* uncross-point the structs under a global lock */
+	spin_lock(&afs_server_peer_lock);
+	peer = server->peer;
+	if (peer) {
+		server->peer = NULL;
+		peer->user = NULL;
+	}
+	spin_unlock(&afs_server_peer_lock);
+
+	/* finish cleaning up the server */
+	for (loop = AFS_SERVER_CONN_LIST_SIZE - 1; loop >= 0; loop--)
+		if (server->fs_conn[loop])
+			rxrpc_put_connection(server->fs_conn[loop]);
+
+	if (server->vlserver)
+		rxrpc_put_connection(server->vlserver);
+
+	kfree(server);
+
+	_leave(" [destroyed]");
+} /* end afs_server_do_timeout() */
+
+/*****************************************************************************/
+/*
+ * get a callslot on a connection to the fileserver on the specified server
+ */
+int afs_server_request_callslot(struct afs_server *server,
+				struct afs_server_callslot *callslot)
+{
+	struct afs_server_callslot *pcallslot;
+	struct rxrpc_connection *conn;
+	int nconn, ret;
+
+	_enter("%p,",server);
+
+	INIT_LIST_HEAD(&callslot->link);
+	callslot->task = current;
+	callslot->conn = NULL;
+	callslot->nconn = -1;
+	callslot->ready = 0;
+
+	ret = 0;
+	conn = NULL;
+
+	/* get hold of a callslot first */
+	spin_lock(&server->fs_lock);
+
+	/* resurrect the server if it's death timeout has expired */
+	if (server->fs_state) {
+		if (time_before(jiffies, server->fs_dead_jif)) {
+			ret = server->fs_state;
+			spin_unlock(&server->fs_lock);
+			_leave(" = %d [still dead]", ret);
+			return ret;
+		}
+
+		server->fs_state = 0;
+	}
+
+	/* try and find a connection that has spare callslots */
+	for (nconn = 0; nconn < AFS_SERVER_CONN_LIST_SIZE; nconn++) {
+		if (server->fs_conn_cnt[nconn] > 0) {
+			server->fs_conn_cnt[nconn]--;
+			spin_unlock(&server->fs_lock);
+			callslot->nconn = nconn;
+			goto obtained_slot;
+		}
+	}
+
+	/* none were available - wait interruptibly for one to become
+	 * available */
+	set_current_state(TASK_INTERRUPTIBLE);
+	list_add_tail(&callslot->link, &server->fs_callq);
+	spin_unlock(&server->fs_lock);
+
+	while (!callslot->ready && !signal_pending(current)) {
+		schedule();
+		set_current_state(TASK_INTERRUPTIBLE);
+	}
+
+	set_current_state(TASK_RUNNING);
+
+	/* even if we were interrupted we may still be queued */
+	if (!callslot->ready) {
+		spin_lock(&server->fs_lock);
+		list_del_init(&callslot->link);
+		spin_unlock(&server->fs_lock);
+	}
+
+	nconn = callslot->nconn;
+
+	/* if interrupted, we must release any slot we also got before
+	 * returning an error */
+	if (signal_pending(current)) {
+		ret = -EINTR;
+		goto error_release;
+	}
+
+	/* if we were woken up with an error, then pass that error back to the
+	 * called */
+	if (nconn < 0) {
+		_leave(" = %d", callslot->errno);
+		return callslot->errno;
+	}
+
+	/* were we given a connection directly? */
+	if (callslot->conn) {
+		/* yes - use it */
+		_leave(" = 0 (nc=%d)", nconn);
+		return 0;
+	}
+
+	/* got a callslot, but no connection */
+ obtained_slot:
+
+	/* need to get hold of the RxRPC connection */
+	down_write(&server->sem);
+
+	/* quick check to see if there's an outstanding error */
+	ret = server->fs_state;
+	if (ret)
+		goto error_release_upw;
+
+	if (server->fs_conn[nconn]) {
+		/* reuse an existing connection */
+		rxrpc_get_connection(server->fs_conn[nconn]);
+		callslot->conn = server->fs_conn[nconn];
+	}
+	else {
+		/* create a new connection */
+		ret = rxrpc_create_connection(afs_transport,
+					      htons(7000),
+					      server->addr.s_addr,
+					      FS_SERVICE_ID,
+					      NULL,
+					      &server->fs_conn[nconn]);
+
+		if (ret < 0)
+			goto error_release_upw;
+
+		callslot->conn = server->fs_conn[0];
+		rxrpc_get_connection(callslot->conn);
+	}
+
+	up_write(&server->sem);
+
+ 	_leave(" = 0");
+	return 0;
+
+	/* handle an error occurring */
+ error_release_upw:
+	up_write(&server->sem);
+
+ error_release:
+	/* either release the callslot or pass it along to another deserving
+	 * task */
+	spin_lock(&server->fs_lock);
+
+	if (nconn < 0) {
+		/* no callslot allocated */
+	}
+	else if (list_empty(&server->fs_callq)) {
+		/* no one waiting */
+		server->fs_conn_cnt[nconn]++;
+		spin_unlock(&server->fs_lock);
+	}
+	else {
+		/* someone's waiting - dequeue them and wake them up */
+		pcallslot = list_entry(server->fs_callq.next,
+				       struct afs_server_callslot, link);
+		list_del_init(&pcallslot->link);
+
+		pcallslot->errno = server->fs_state;
+		if (!pcallslot->errno) {
+			/* pass them out callslot details */
+			callslot->conn = xchg(&pcallslot->conn,
+					      callslot->conn);
+			pcallslot->nconn = nconn;
+			callslot->nconn = nconn = -1;
+		}
+		pcallslot->ready = 1;
+		wake_up_process(pcallslot->task);
+		spin_unlock(&server->fs_lock);
+	}
+
+	rxrpc_put_connection(callslot->conn);
+	callslot->conn = NULL;
+
+	_leave(" = %d", ret);
+	return ret;
+
+} /* end afs_server_request_callslot() */
+
+/*****************************************************************************/
+/*
+ * release a callslot back to the server
+ * - transfers the RxRPC connection to the next pending callslot if possible
+ */
+void afs_server_release_callslot(struct afs_server *server,
+				 struct afs_server_callslot *callslot)
+{
+	struct afs_server_callslot *pcallslot;
+
+	_enter("{ad=%08x,cnt=%u},{%d}",
+	       ntohl(server->addr.s_addr),
+	       server->fs_conn_cnt[callslot->nconn],
+	       callslot->nconn);
+
+	BUG_ON(callslot->nconn < 0);
+
+	spin_lock(&server->fs_lock);
+
+	if (list_empty(&server->fs_callq)) {
+		/* no one waiting */
+		server->fs_conn_cnt[callslot->nconn]++;
+		spin_unlock(&server->fs_lock);
+	}
+	else {
+		/* someone's waiting - dequeue them and wake them up */
+		pcallslot = list_entry(server->fs_callq.next,
+				       struct afs_server_callslot, link);
+		list_del_init(&pcallslot->link);
+
+		pcallslot->errno = server->fs_state;
+		if (!pcallslot->errno) {
+			/* pass them out callslot details */
+			callslot->conn = xchg(&pcallslot->conn, callslot->conn);
+			pcallslot->nconn = callslot->nconn;
+			callslot->nconn = -1;
+		}
+
+		pcallslot->ready = 1;
+		wake_up_process(pcallslot->task);
+		spin_unlock(&server->fs_lock);
+	}
+
+	rxrpc_put_connection(callslot->conn);
+
+	_leave("");
+} /* end afs_server_release_callslot() */
+
+/*****************************************************************************/
+/*
+ * get a handle to a connection to the vlserver (volume location) on the
+ * specified server
+ */
+int afs_server_get_vlconn(struct afs_server *server,
+			  struct rxrpc_connection **_conn)
+{
+	struct rxrpc_connection *conn;
+	int ret;
+
+	_enter("%p,", server);
+
+	ret = 0;
+	conn = NULL;
+	down_read(&server->sem);
+
+	if (server->vlserver) {
+		/* reuse an existing connection */
+		rxrpc_get_connection(server->vlserver);
+		conn = server->vlserver;
+		up_read(&server->sem);
+	}
+	else {
+		/* create a new connection */
+		up_read(&server->sem);
+		down_write(&server->sem);
+		if (!server->vlserver) {
+			ret = rxrpc_create_connection(afs_transport,
+						      htons(7003),
+						      server->addr.s_addr,
+						      VL_SERVICE_ID,
+						      NULL,
+						      &server->vlserver);
+		}
+		if (ret == 0) {
+			rxrpc_get_connection(server->vlserver);
+			conn = server->vlserver;
+		}
+		up_write(&server->sem);
+	}
+
+	*_conn = conn;
+	_leave(" = %d", ret);
+	return ret;
+} /* end afs_server_get_vlconn() */