1 files changed, 236 insertions, 411 deletions

diff --git a/fs/afs/server.c b/fs/afs/server.c
index 44aff81dc6a7..96bb23b476a2 100644
--- a/fs/afs/server.c
+++ b/fs/afs/server.c
@@ -1,6 +1,6 @@
-/* server.c: AFS server record management
+/* AFS server record management
  *
- * Copyright (C) 2002 Red Hat, Inc. All Rights Reserved.
+ * Copyright (C) 2002, 2007 Red Hat, Inc. All Rights Reserved.
  * Written by David Howells (dhowells@redhat.com)
  *
  * This program is free software; you can redistribute it and/or
@@ -11,489 +11,314 @@
 
 #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);
+unsigned afs_server_timeout = 10;	/* server timeout in seconds */
 
-#define FS_SERVICE_ID		1	/* AFS Volume Location Service ID */
-#define VL_SERVICE_ID		52	/* AFS Volume Location Service ID */
+static void afs_reap_server(struct work_struct *);
 
-static void __afs_server_timeout(struct afs_timer *timer)
+/* tree of all the servers, indexed by IP address */
+static struct rb_root afs_servers = RB_ROOT;
+static DEFINE_RWLOCK(afs_servers_lock);
+
+/* LRU list of all the servers not currently in use */
+static LIST_HEAD(afs_server_graveyard);
+static DEFINE_SPINLOCK(afs_server_graveyard_lock);
+static DECLARE_DELAYED_WORK(afs_server_reaper, afs_reap_server);
+
+/*
+ * install a server record in the master tree
+ */
+static int afs_install_server(struct afs_server *server)
 {
-	struct afs_server *server =
-		list_entry(timer, struct afs_server, timeout);
+	struct afs_server *xserver;
+	struct rb_node **pp, *p;
+	int ret;
 
-	_debug("SERVER TIMEOUT [%p{u=%d}]",
-	       server, atomic_read(&server->usage));
+	_enter("%p", server);
 
-	afs_server_do_timeout(server);
-}
+	write_lock(&afs_servers_lock);
+
+	ret = -EEXIST;
+	pp = &afs_servers.rb_node;
+	p = NULL;
+	while (*pp) {
+		p = *pp;
+		_debug("- consider %p", p);
+		xserver = rb_entry(p, struct afs_server, master_rb);
+		if (server->addr.s_addr < xserver->addr.s_addr)
+			pp = &(*pp)->rb_left;
+		else if (server->addr.s_addr > xserver->addr.s_addr)
+			pp = &(*pp)->rb_right;
+		else
+			goto error;
+	}
 
-static const struct afs_timer_ops afs_server_timer_ops = {
-	.timed_out	= __afs_server_timeout,
-};
+	rb_link_node(&server->master_rb, p, pp);
+	rb_insert_color(&server->master_rb, &afs_servers);
+	ret = 0;
+
+error:
+	write_unlock(&afs_servers_lock);
+	return ret;
+}
 
-/*****************************************************************************/
 /*
- * lookup a server record in a cell
- * - TODO: search the cell's server list
+ * allocate a new server record
  */
-int afs_server_lookup(struct afs_cell *cell, const struct in_addr *addr,
-		      struct afs_server **_server)
+static struct afs_server *afs_alloc_server(struct afs_cell *cell,
+					   const struct in_addr *addr)
 {
-	struct afs_server *server, *active, *zombie;
-	int loop;
+	struct afs_server *server;
 
-	_enter("%p,%08x,", cell, ntohl(addr->s_addr));
+	_enter("");
 
-	/* allocate and initialise a server record */
 	server = kzalloc(sizeof(struct afs_server), GFP_KERNEL);
-	if (!server) {
-		_leave(" = -ENOMEM");
-		return -ENOMEM;
+	if (server) {
+		atomic_set(&server->usage, 1);
+		server->cell = cell;
+
+		INIT_LIST_HEAD(&server->link);
+		INIT_LIST_HEAD(&server->grave);
+		init_rwsem(&server->sem);
+		spin_lock_init(&server->fs_lock);
+		server->fs_vnodes = RB_ROOT;
+		server->cb_promises = RB_ROOT;
+		spin_lock_init(&server->cb_lock);
+		init_waitqueue_head(&server->cb_break_waitq);
+		INIT_DELAYED_WORK(&server->cb_break_work,
+				  afs_dispatch_give_up_callbacks);
+
+		memcpy(&server->addr, addr, sizeof(struct in_addr));
+		server->addr.s_addr = addr->s_addr;
 	}
 
-	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;
+	_leave(" = %p{%d}", server, atomic_read(&server->usage));
+	return server;
+}
 
-	memcpy(&server->addr, addr, sizeof(struct in_addr));
-	server->addr.s_addr = addr->s_addr;
+/*
+ * get an FS-server record for a cell
+ */
+struct afs_server *afs_lookup_server(struct afs_cell *cell,
+				     const struct in_addr *addr)
+{
+	struct afs_server *server, *candidate;
 
-	afs_timer_init(&server->timeout, &afs_server_timer_ops);
+	_enter("%p,"NIPQUAD_FMT, cell, NIPQUAD(addr->s_addr));
 
-	/* add to the cell */
-	write_lock(&cell->sv_lock);
+	/* quick scan of the list to see if we already have the server */
+	read_lock(&cell->servers_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;
+	list_for_each_entry(server, &cell->servers, link) {
+		if (server->addr.s_addr == addr->s_addr)
+			goto found_server_quickly;
 	}
+	read_unlock(&cell->servers_lock);
 
-	/* 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;
+	candidate = afs_alloc_server(cell, addr);
+	if (!candidate) {
+		_leave(" = -ENOMEM");
+		return ERR_PTR(-ENOMEM);
 	}
-	spin_unlock(&cell->sv_gylock);
 
-	afs_get_cell(cell);
-	server->cell = cell;
-	list_add_tail(&server->link, &cell->sv_list);
+	write_lock(&cell->servers_lock);
 
-	write_unlock(&cell->sv_lock);
+	/* check the cell's server list again */
+	list_for_each_entry(server, &cell->servers, link) {
+		if (server->addr.s_addr == addr->s_addr)
+			goto found_server;
+	}
 
-	*_server = server;
-	_leave(" = 0 (%p)", server);
-	return 0;
+	_debug("new");
+	server = candidate;
+	if (afs_install_server(server) < 0)
+		goto server_in_two_cells;
 
-	/* found a matching active server */
- use_active_server:
-	_debug("active server");
-	afs_get_server(active);
-	write_unlock(&cell->sv_lock);
+	afs_get_cell(cell);
+	list_add_tail(&server->link, &cell->servers);
+
+	write_unlock(&cell->servers_lock);
+	_leave(" = %p{%d}", server, atomic_read(&server->usage));
+	return server;
+
+	/* found a matching server quickly */
+found_server_quickly:
+	_debug("found quickly");
+	afs_get_server(server);
+	read_unlock(&cell->servers_lock);
+no_longer_unused:
+	if (!list_empty(&server->grave)) {
+		spin_lock(&afs_server_graveyard_lock);
+		list_del_init(&server->grave);
+		spin_unlock(&afs_server_graveyard_lock);
+	}
+	_leave(" = %p{%d}", server, atomic_read(&server->usage));
+	return server;
+
+	/* found a matching server on the second pass */
+found_server:
+	_debug("found");
+	afs_get_server(server);
+	write_unlock(&cell->servers_lock);
+	kfree(candidate);
+	goto no_longer_unused;
+
+	/* found a server that seems to be in two cells */
+server_in_two_cells:
+	write_unlock(&cell->servers_lock);
+	kfree(candidate);
+	printk(KERN_NOTICE "kAFS:"
+	       " Server "NIPQUAD_FMT" appears to be in two cells\n",
+	       NIPQUAD(*addr));
+	_leave(" = -EEXIST");
+	return ERR_PTR(-EEXIST);
+}
 
-	kfree(server);
+/*
+ * look up a server by its IP address
+ */
+struct afs_server *afs_find_server(const struct in_addr *_addr)
+{
+	struct afs_server *server = NULL;
+	struct rb_node *p;
+	struct in_addr addr = *_addr;
 
-	*_server = active;
-	_leave(" = 0 (%p)", active);
-	return 0;
+	_enter(NIPQUAD_FMT, NIPQUAD(addr.s_addr));
 
-	/* found a matching server in the graveyard, so resurrect it and
-	 * dispose of the new record */
- resurrect_server:
-	_debug("resurrecting server");
+	read_lock(&afs_servers_lock);
 
-	list_move_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);
+	p = afs_servers.rb_node;
+	while (p) {
+		server = rb_entry(p, struct afs_server, master_rb);
 
-	kfree(server);
+		_debug("- consider %p", p);
 
-	*_server = zombie;
-	_leave(" = 0 (%p)", zombie);
-	return 0;
+		if (addr.s_addr < server->addr.s_addr) {
+			p = p->rb_left;
+		} else if (addr.s_addr > server->addr.s_addr) {
+			p = p->rb_right;
+		} else {
+			afs_get_server(server);
+			goto found;
+		}
+	}
 
-} /* end afs_server_lookup() */
+	server = NULL;
+found:
+	read_unlock(&afs_servers_lock);
+	ASSERTIFCMP(server, server->addr.s_addr, ==, addr.s_addr);
+	_leave(" = %p", server);
+	return server;
+}
 
-/*****************************************************************************/
 /*
  * 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;
+	_enter("%p{%d}", server, atomic_read(&server->usage));
 
-	/* sanity check */
-	BUG_ON(atomic_read(&server->usage) <= 0);
+	_debug("PUT SERVER %d", atomic_read(&server->usage));
 
-	/* to prevent a race, the decrement and the dequeue must be effectively
-	 * atomic */
-	write_lock(&cell->sv_lock);
+	ASSERTCMP(atomic_read(&server->usage), >, 0);
 
 	if (likely(!atomic_dec_and_test(&server->usage))) {
-		write_unlock(&cell->sv_lock);
 		_leave("");
 		return;
 	}
 
-	spin_lock(&cell->sv_gylock);
-	list_move_tail(&server->link, &cell->sv_graveyard);
+	afs_flush_callback_breaks(server);
 
-	/* 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() */
+	spin_lock(&afs_server_graveyard_lock);
+	if (atomic_read(&server->usage) == 0) {
+		list_move_tail(&server->grave, &afs_server_graveyard);
+		server->time_of_death = get_seconds();
+		schedule_delayed_work(&afs_server_reaper,
+				      afs_server_timeout * HZ);
+	}
+	spin_unlock(&afs_server_graveyard_lock);
+	_leave(" [dead]");
+}
 
-/*****************************************************************************/
 /*
- * timeout server record
- * - removes from the cell's graveyard if the usage count is zero
+ * destroy a dead server
  */
-void afs_server_do_timeout(struct afs_server *server)
+static void afs_destroy_server(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);
+	ASSERTCMP(server->fs_vnodes.rb_node, ==, NULL);
+	ASSERTCMP(server->cb_promises.rb_node, ==, NULL);
+	ASSERTCMP(server->cb_break_head, ==, server->cb_break_tail);
+	ASSERTCMP(atomic_read(&server->cb_break_n), ==, 0);
 
+	afs_put_cell(server->cell);
 	kfree(server);
+}
 
-	_leave(" [destroyed]");
-} /* end afs_server_do_timeout() */
-
-/*****************************************************************************/
 /*
- * get a callslot on a connection to the fileserver on the specified server
+ * reap dead server records
  */
-int afs_server_request_callslot(struct afs_server *server,
-				struct afs_server_callslot *callslot)
+static void afs_reap_server(struct work_struct *work)
 {
-	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;
+	LIST_HEAD(corpses);
+	struct afs_server *server;
+	unsigned long delay, expiry;
+	time_t now;
+
+	now = get_seconds();
+	spin_lock(&afs_server_graveyard_lock);
+
+	while (!list_empty(&afs_server_graveyard)) {
+		server = list_entry(afs_server_graveyard.next,
+				    struct afs_server, grave);
+
+		/* the queue is ordered most dead first */
+		expiry = server->time_of_death + afs_server_timeout;
+		if (expiry > now) {
+			delay = (expiry - now) * HZ;
+			if (!schedule_delayed_work(&afs_server_reaper, delay)) {
+				cancel_delayed_work(&afs_server_reaper);
+				schedule_delayed_work(&afs_server_reaper,
+						      delay);
+			}
+			break;
 		}
 
-		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;
+		write_lock(&server->cell->servers_lock);
+		write_lock(&afs_servers_lock);
+		if (atomic_read(&server->usage) > 0) {
+			list_del_init(&server->grave);
+		} else {
+			list_move_tail(&server->grave, &corpses);
+			list_del_init(&server->link);
+			rb_erase(&server->master_rb, &afs_servers);
 		}
+		write_unlock(&afs_servers_lock);
+		write_unlock(&server->cell->servers_lock);
 	}
 
-	/* 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;
+	spin_unlock(&afs_server_graveyard_lock);
 
-	/* if interrupted, we must release any slot we also got before
-	 * returning an error */
-	if (signal_pending(current)) {
-		ret = -EINTR;
-		goto error_release;
+	/* now reap the corpses we've extracted */
+	while (!list_empty(&corpses)) {
+		server = list_entry(corpses.next, struct afs_server, grave);
+		list_del(&server->grave);
+		afs_destroy_server(server);
 	}
+}
 
-	/* 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
+ * discard all the server records for rmmod
  */
-int afs_server_get_vlconn(struct afs_server *server,
-			  struct rxrpc_connection **_conn)
+void __exit afs_purge_servers(void)
 {
-	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() */
+	afs_server_timeout = 0;
+	cancel_delayed_work(&afs_server_reaper);
+	schedule_delayed_work(&afs_server_reaper, 0);
+}