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-rw-r--r--fs/afs/server.c502
1 files changed, 502 insertions, 0 deletions
diff --git a/fs/afs/server.c b/fs/afs/server.c
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+++ 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() */