-/* 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
#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);
+static 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)
-{
- 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);
-}
+/* tree of all the servers, indexed by IP address */
+static struct rb_root afs_servers = RB_ROOT;
+static DEFINE_RWLOCK(afs_servers_lock);
-static const struct afs_timer_ops afs_server_timer_ops = {
- .timed_out = __afs_server_timeout,
-};
+/* 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);
-/*****************************************************************************/
/*
- * lookup a server record in a cell
- * - TODO: search the cell's server list
+ * install a server record in the master tree
*/
-int afs_server_lookup(struct afs_cell *cell, const struct in_addr *addr,
- struct afs_server **_server)
+static int afs_install_server(struct afs_server *server)
{
- struct afs_server *server, *active, *zombie;
- int loop;
+ struct afs_server *xserver;
+ struct rb_node **pp, *p;
+ int ret;
- _enter("%p,%08x,", cell, ntohl(addr->s_addr));
+ _enter("%p", server);
- /* allocate and initialise a server record */
- server = kmalloc(sizeof(struct afs_server), GFP_KERNEL);
- if (!server) {
- _leave(" = -ENOMEM");
- return -ENOMEM;
+ 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;
}
- memset(server, 0, sizeof(struct afs_server));
- atomic_set(&server->usage, 1);
+ rb_link_node(&server->master_rb, p, pp);
+ rb_insert_color(&server->master_rb, &afs_servers);
+ ret = 0;
- 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);
+error:
+ write_unlock(&afs_servers_lock);
+ return ret;
+}
- for (loop = 0; loop < AFS_SERVER_CONN_LIST_SIZE; loop++)
- server->fs_conn_cnt[loop] = 4;
+/*
+ * allocate a new server record
+ */
+static struct afs_server *afs_alloc_server(struct afs_cell *cell,
+ const struct in_addr *addr)
+{
+ struct afs_server *server;
+
+ _enter("");
+
+ server = kzalloc(sizeof(struct afs_server), GFP_KERNEL);
+ 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;
+ }
- memcpy(&server->addr, addr, sizeof(struct in_addr));
- server->addr.s_addr = addr->s_addr;
+ _leave(" = %p{%d}", server, atomic_read(&server->usage));
+ return server;
+}
- afs_timer_init(&server->timeout, &afs_server_timer_ops);
+/*
+ * 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;
+
+ _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);
+ ASSERTIF(server->cb_break_head != server->cb_break_tail,
+ delayed_work_pending(&server->cb_break_work));
- 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;
- }
- }
-
- /* 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;
+ 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);
}
- pcallslot->ready = 1;
- wake_up_process(pcallslot->task);
- spin_unlock(&server->fs_lock);
+ write_unlock(&afs_servers_lock);
+ write_unlock(&server->cell->servers_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;
- }
+ spin_unlock(&afs_server_graveyard_lock);
- pcallslot->ready = 1;
- wake_up_process(pcallslot->task);
- spin_unlock(&server->fs_lock);
+ /* 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);
}
+}
- 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);
+}
git.openpandora.org / pandora-kernel.git / blobdiff