summaryrefslogtreecommitdiff
path: root/fs/afs/vl_rotate.c
diff options
context:
space:
mode:
authorDavid Howells <dhowells@redhat.com>2018-10-20 02:57:59 +0300
committerDavid Howells <dhowells@redhat.com>2018-10-24 02:41:09 +0300
commit3bf0fb6f33dd545693da5e65f5b1b9b9f0bfc35e (patch)
treedf215e6a6ad11b6ac8158461144667e168591d28 /fs/afs/vl_rotate.c
parent18ac61853cc4e44eb30e125fc8344a3b25c7b6fe (diff)
downloadlinux-3bf0fb6f33dd545693da5e65f5b1b9b9f0bfc35e.tar.xz
afs: Probe multiple fileservers simultaneously
Send probes to all the unprobed fileservers in a fileserver list on all addresses simultaneously in an attempt to find out the fastest route whilst not getting stuck for 20s on any server or address that we don't get a reply from. This alleviates the problem whereby attempting to access a new server can take a long time because the rotation algorithm ends up rotating through all servers and addresses until it finds one that responds. Signed-off-by: David Howells <dhowells@redhat.com>
Diffstat (limited to 'fs/afs/vl_rotate.c')
-rw-r--r--fs/afs/vl_rotate.c159
1 files changed, 105 insertions, 54 deletions
diff --git a/fs/afs/vl_rotate.c b/fs/afs/vl_rotate.c
index ead6dedbb561..b64a284b99d2 100644
--- a/fs/afs/vl_rotate.c
+++ b/fs/afs/vl_rotate.c
@@ -58,8 +58,8 @@ static bool afs_start_vl_iteration(struct afs_vl_cursor *vc)
if (!vc->server_list || !vc->server_list->nr_servers)
return false;
- vc->start = READ_ONCE(vc->server_list->index);
- vc->index = vc->start;
+ vc->untried = (1UL << vc->server_list->nr_servers) - 1;
+ vc->index = -1;
return true;
}
@@ -71,11 +71,12 @@ bool afs_select_vlserver(struct afs_vl_cursor *vc)
{
struct afs_addr_list *alist;
struct afs_vlserver *vlserver;
- int error = vc->ac.error;
+ u32 rtt;
+ int error = vc->ac.error, abort_code, i;
- _enter("%u/%u,%u/%u,%d,%d",
- vc->index, vc->start,
- vc->ac.index, vc->ac.start,
+ _enter("%lx[%d],%lx[%d],%d,%d",
+ vc->untried, vc->index,
+ vc->ac.tried, vc->ac.index,
error, vc->ac.abort_code);
if (vc->flags & AFS_VL_CURSOR_STOP) {
@@ -145,23 +146,52 @@ restart_from_beginning:
start:
_debug("start");
- /* TODO: Consider checking the VL server list */
-
if (!afs_start_vl_iteration(vc))
goto failed;
-use_server:
- _debug("use");
+ error = afs_send_vl_probes(vc->cell->net, vc->key, vc->server_list);
+ if (error < 0)
+ goto failed_set_error;
+
+pick_server:
+ _debug("pick [%lx]", vc->untried);
+
+ error = afs_wait_for_vl_probes(vc->server_list, vc->untried);
+ if (error < 0)
+ goto failed_set_error;
+
+ /* Pick the untried server with the lowest RTT. */
+ vc->index = vc->server_list->preferred;
+ if (test_bit(vc->index, &vc->untried))
+ goto selected_server;
+
+ vc->index = -1;
+ rtt = U32_MAX;
+ for (i = 0; i < vc->server_list->nr_servers; i++) {
+ struct afs_vlserver *s = vc->server_list->servers[i].server;
+
+ if (!test_bit(i, &vc->untried) || !s->probe.responded)
+ continue;
+ if (s->probe.rtt < rtt) {
+ vc->index = i;
+ rtt = s->probe.rtt;
+ }
+ }
+
+ if (vc->index == -1)
+ goto no_more_servers;
+
+selected_server:
+ _debug("use %d", vc->index);
+ __clear_bit(vc->index, &vc->untried);
+
/* We're starting on a different vlserver from the list. We need to
* check it, find its address list and probe its capabilities before we
* use it.
*/
ASSERTCMP(vc->ac.alist, ==, NULL);
vlserver = vc->server_list->servers[vc->index].server;
-
- // TODO: Check the vlserver occasionally
- //if (!afs_check_vlserver_record(vc, vlserver))
- // goto failed;
+ vc->server = vlserver;
_debug("USING VLSERVER: %s", vlserver->name);
@@ -173,62 +203,84 @@ use_server:
memset(&vc->ac, 0, sizeof(vc->ac));
- /* Probe the current vlserver if we haven't done so yet. */
-#if 0 // TODO
- if (!test_bit(AFS_VLSERVER_FL_PROBED, &vlserver->flags)) {
- vc->ac.alist = afs_get_addrlist(alist);
-
- if (!afs_probe_vlserver(vc)) {
- error = vc->ac.error;
- switch (error) {
- case -ENOMEM:
- case -ERESTARTSYS:
- case -EINTR:
- goto failed_set_error;
- default:
- goto next_server;
- }
- }
- }
-#endif
-
if (!vc->ac.alist)
vc->ac.alist = alist;
else
afs_put_addrlist(alist);
- vc->ac.start = READ_ONCE(alist->index);
- vc->ac.index = vc->ac.start;
+ vc->ac.index = -1;
iterate_address:
ASSERT(vc->ac.alist);
- _debug("iterate %d/%d", vc->ac.index, vc->ac.alist->nr_addrs);
/* Iterate over the current server's address list to try and find an
* address on which it will respond to us.
*/
if (!afs_iterate_addresses(&vc->ac))
goto next_server;
+ _debug("VL address %d/%d", vc->ac.index, vc->ac.alist->nr_addrs);
+
_leave(" = t %pISpc", &vc->ac.alist->addrs[vc->ac.index].transport);
return true;
next_server:
_debug("next");
afs_end_cursor(&vc->ac);
- vc->index++;
- if (vc->index >= vc->server_list->nr_servers)
- vc->index = 0;
- if (vc->index != vc->start)
- goto use_server;
+ goto pick_server;
+no_more_servers:
/* That's all the servers poked to no good effect. Try again if some
* of them were busy.
*/
if (vc->flags & AFS_VL_CURSOR_RETRY)
goto restart_from_beginning;
- goto failed;
+ abort_code = 0;
+ error = -EDESTADDRREQ;
+ for (i = 0; i < vc->server_list->nr_servers; i++) {
+ struct afs_vlserver *s = vc->server_list->servers[i].server;
+ int probe_error = READ_ONCE(s->probe.error);
+
+ switch (probe_error) {
+ case 0:
+ continue;
+ default:
+ if (error == -ETIMEDOUT ||
+ error == -ETIME)
+ continue;
+ case -ETIMEDOUT:
+ case -ETIME:
+ if (error == -ENOMEM ||
+ error == -ENONET)
+ continue;
+ case -ENOMEM:
+ case -ENONET:
+ if (error == -ENETUNREACH)
+ continue;
+ case -ENETUNREACH:
+ if (error == -EHOSTUNREACH)
+ continue;
+ case -EHOSTUNREACH:
+ if (error == -ECONNREFUSED)
+ continue;
+ case -ECONNREFUSED:
+ if (error == -ECONNRESET)
+ continue;
+ case -ECONNRESET: /* Responded, but call expired. */
+ if (error == -ECONNABORTED)
+ continue;
+ case -ECONNABORTED:
+ abort_code = s->probe.abort_code;
+ error = probe_error;
+ continue;
+ }
+ }
+
+ if (error == -ECONNABORTED)
+ error = afs_abort_to_error(abort_code);
+failed_set_error:
+ vc->error = error;
failed:
vc->flags |= AFS_VL_CURSOR_STOP;
afs_end_cursor(&vc->ac);
@@ -250,8 +302,8 @@ static void afs_vl_dump_edestaddrreq(const struct afs_vl_cursor *vc)
rcu_read_lock();
pr_notice("EDESTADDR occurred\n");
- pr_notice("VC: st=%u ix=%u ni=%hu fl=%hx err=%hd\n",
- vc->start, vc->index, vc->nr_iterations, vc->flags, vc->error);
+ pr_notice("VC: ut=%lx ix=%u ni=%hu fl=%hx err=%hd\n",
+ vc->untried, vc->index, vc->nr_iterations, vc->flags, vc->error);
if (vc->server_list) {
const struct afs_vlserver_list *sl = vc->server_list;
@@ -259,26 +311,25 @@ static void afs_vl_dump_edestaddrreq(const struct afs_vl_cursor *vc)
sl->nr_servers, sl->index);
for (i = 0; i < sl->nr_servers; i++) {
const struct afs_vlserver *s = sl->servers[i].server;
- pr_notice("VC: server fl=%lx %s+%hu\n",
- s->flags, s->name, s->port);
+ pr_notice("VC: server %s+%hu fl=%lx E=%hd\n",
+ s->name, s->port, s->flags, s->probe.error);
if (s->addresses) {
const struct afs_addr_list *a =
rcu_dereference(s->addresses);
- pr_notice("VC: - av=%u nr=%u/%u/%u ax=%u\n",
- a->version,
+ pr_notice("VC: - nr=%u/%u/%u pf=%u\n",
a->nr_ipv4, a->nr_addrs, a->max_addrs,
- a->index);
- pr_notice("VC: - pr=%lx yf=%lx\n",
- a->probed, a->yfs);
+ a->preferred);
+ pr_notice("VC: - pr=%lx R=%lx F=%lx\n",
+ a->probed, a->responded, a->failed);
if (a == vc->ac.alist)
pr_notice("VC: - current\n");
}
}
}
- pr_notice("AC: as=%u ax=%u ac=%d er=%d b=%u r=%u ni=%hu\n",
- vc->ac.start, vc->ac.index, vc->ac.abort_code, vc->ac.error,
- vc->ac.begun, vc->ac.responded, vc->ac.nr_iterations);
+ pr_notice("AC: t=%lx ax=%u ac=%d er=%d r=%u ni=%u\n",
+ vc->ac.tried, vc->ac.index, vc->ac.abort_code, vc->ac.error,
+ vc->ac.responded, vc->ac.nr_iterations);
rcu_read_unlock();
}