1 files changed, 502 insertions, 0 deletions

diff --git a/fs/afs/server.c b/fs/afs/server.c
new file mode 100644
index 000000000000..62b093aa41c6
--- /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() */