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afs: Fix server reaping 

Fix server reaping and make sure it's all done before we start trying to
purge cells, given that servers currently pin cells.

Signed-off-by: David Howells <dhowells@redhat.com>
This commit is contained in:
David Howells 2017-11-02 15:27:45 +00:00
parent e3b2ffe0f0
commit 59fa1c4a9f
3 changed files with 57 additions and 10 deletions
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5
fs/afs/internal.h
View File

@ -238,7 +238,9 @@ struct afs_net {
rwlock_t servers_lock;
struct list_head server_graveyard; /* Inactive server LRU list */
spinlock_t server_graveyard_lock;
struct delayed_work server_reaper;
struct timer_list server_timer;
struct work_struct server_reaper;
atomic_t servers_outstanding;
/* Misc */
struct proc_dir_entry *proc_afs; /* /proc/net/afs directory */
@ -700,6 +702,7 @@ do { \
atomic_inc(&(S)->usage); \
} while(0)
extern void afs_server_timer(struct timer_list *);
extern struct afs_server *afs_lookup_server(struct afs_cell *,
const struct in_addr *);
extern struct afs_server *afs_find_server(struct afs_net *,

3
fs/afs/main.c
View File

@ -62,7 +62,8 @@ static int __net_init afs_net_init(struct afs_net *net)
rwlock_init(&net->servers_lock);
INIT_LIST_HEAD(&net->server_graveyard);
spin_lock_init(&net->server_graveyard_lock);
INIT_DELAYED_WORK(&net->server_reaper, afs_reap_server);
INIT_WORK(&net->server_reaper, afs_reap_server);
timer_setup(&net->server_timer, afs_server_timer, 0);
/* Register the /proc stuff */
ret = afs_proc_init(net);

59
fs/afs/server.c
View File

@ -15,6 +15,25 @@
static unsigned afs_server_timeout = 10; /* server timeout in seconds */
static void afs_inc_servers_outstanding(struct afs_net *net)
{
atomic_inc(&net->servers_outstanding);
}
static void afs_dec_servers_outstanding(struct afs_net *net)
{
if (atomic_dec_and_test(&net->servers_outstanding))
wake_up_atomic_t(&net->servers_outstanding);
}
void afs_server_timer(struct timer_list *timer)
{
struct afs_net *net = container_of(timer, struct afs_net, server_timer);
if (!queue_work(afs_wq, &net->server_reaper))
afs_dec_servers_outstanding(net);
}
/*
* install a server record in the master tree
*/
@ -81,6 +100,7 @@ static struct afs_server *afs_alloc_server(struct afs_cell *cell,
memcpy(&server->addr, addr, sizeof(struct in_addr));
server->addr.s_addr = addr->s_addr;
afs_inc_servers_outstanding(cell->net);
_leave(" = %p{%d}", server, atomic_read(&server->usage));
} else {
_leave(" = NULL [nomem]");
@ -159,6 +179,7 @@ found_server:
server_in_two_cells:
write_unlock(&cell->servers_lock);
kfree(candidate);
afs_dec_servers_outstanding(cell->net);
printk(KERN_NOTICE "kAFS: Server %pI4 appears to be in two cells\n",
addr);
_leave(" = -EEXIST");
@ -208,6 +229,18 @@ found:
return server;
}
static void afs_set_server_timer(struct afs_net *net, time64_t delay)
{
afs_inc_servers_outstanding(net);
if (net->live) {
if (timer_reduce(&net->server_timer, jiffies + delay * HZ))
afs_dec_servers_outstanding(net);
} else {
if (!queue_work(afs_wq, &net->server_reaper))
afs_dec_servers_outstanding(net);
}
}
/*
* destroy a server record
* - removes from the cell list
@ -236,8 +269,7 @@ void afs_put_server(struct afs_server *server)
if (atomic_read(&server->usage) == 0) {
list_move_tail(&server->grave, &net->server_graveyard);
server->time_of_death = ktime_get_real_seconds();
queue_delayed_work(afs_wq, &net->server_reaper,
net->live ? afs_server_timeout * HZ : 0);
afs_set_server_timer(net, afs_server_timeout);
}
spin_unlock(&net->server_graveyard_lock);
_leave(" [dead]");
@ -246,7 +278,7 @@ void afs_put_server(struct afs_server *server)
/*
* destroy a dead server
*/
static void afs_destroy_server(struct afs_server *server)
static void afs_destroy_server(struct afs_net *net, struct afs_server *server)
{
_enter("%p", server);
@ -260,6 +292,7 @@ static void afs_destroy_server(struct afs_server *server)
afs_put_cell(server->cell);
kfree(server);
afs_dec_servers_outstanding(net);
}
/*
@ -269,7 +302,7 @@ void afs_reap_server(struct work_struct *work)
{
LIST_HEAD(corpses);
struct afs_server *server;
struct afs_net *net = container_of(work, struct afs_net, server_reaper.work);
struct afs_net *net = container_of(work, struct afs_net, server_reaper);
unsigned long delay, expiry;
time64_t now;
@ -284,8 +317,8 @@ void afs_reap_server(struct work_struct *work)
if (net->live) {
expiry = server->time_of_death + afs_server_timeout;
if (expiry > now) {
delay = (expiry - now) * HZ;
mod_delayed_work(afs_wq, &net->server_reaper, delay);
delay = (expiry - now);
afs_set_server_timer(net, delay);
break;
}
}
@ -309,8 +342,10 @@ void afs_reap_server(struct work_struct *work)
while (!list_empty(&corpses)) {
server = list_entry(corpses.next, struct afs_server, grave);
list_del(&server->grave);
afs_destroy_server(server);
afs_destroy_server(net, server);
}
afs_dec_servers_outstanding(net);
}
/*
@ -319,5 +354,13 @@ void afs_reap_server(struct work_struct *work)
*/
void __net_exit afs_purge_servers(struct afs_net *net)
{
mod_delayed_work(afs_wq, &net->server_reaper, 0);
if (del_timer_sync(&net->server_timer))
atomic_dec(&net->servers_outstanding);
afs_inc_servers_outstanding(net);
if (!queue_work(afs_wq, &net->server_reaper))
afs_dec_servers_outstanding(net);
wait_on_atomic_t(&net->servers_outstanding, atomic_t_wait,
TASK_UNINTERRUPTIBLE);
}