[PATCH net 6/7] afs: Don't use VL probe running state to make decisions outside probe code
David Howells
dhowells at redhat.com
Thu Aug 27 11:04:15 EDT 2020
Don't use the running state for VL server probes to make decisions about
which server to use as the state is cleared at the start of a probe and
intermediate values might also be misleading.
Instead, add a separate 'latest known' rtt in the afs_vlserver struct and a
flag to indicate if the server is known to be responding and update these
as and when we know what to change them to.
Fixes: 3bf0fb6f33dd ("afs: Probe multiple fileservers simultaneously")
Signed-off-by: David Howells <dhowells at redhat.com>
---
fs/afs/internal.h | 4 +++-
fs/afs/proc.c | 2 +-
fs/afs/vl_list.c | 1 +
fs/afs/vl_probe.c | 57 ++++++++++++++++++++++++++++++++++++----------------
fs/afs/vl_rotate.c | 2 +-
5 files changed, 46 insertions(+), 20 deletions(-)
diff --git a/fs/afs/internal.h b/fs/afs/internal.h
index b29dfcfe5fc2..18042b7dab6a 100644
--- a/fs/afs/internal.h
+++ b/fs/afs/internal.h
@@ -401,15 +401,17 @@ struct afs_vlserver {
#define AFS_VLSERVER_FL_PROBED 0 /* The VL server has been probed */
#define AFS_VLSERVER_FL_PROBING 1 /* VL server is being probed */
#define AFS_VLSERVER_FL_IS_YFS 2 /* Server is YFS not AFS */
+#define AFS_VLSERVER_FL_RESPONDING 3 /* VL server is responding */
rwlock_t lock; /* Lock on addresses */
atomic_t usage;
+ unsigned int rtt; /* Server's current RTT in uS */
/* Probe state */
wait_queue_head_t probe_wq;
atomic_t probe_outstanding;
spinlock_t probe_lock;
struct {
- unsigned int rtt; /* RTT as ktime/64 */
+ unsigned int rtt; /* RTT in uS */
u32 abort_code;
short error;
unsigned short flags;
diff --git a/fs/afs/proc.c b/fs/afs/proc.c
index 5e837155f1a0..e8babb62ed44 100644
--- a/fs/afs/proc.c
+++ b/fs/afs/proc.c
@@ -310,7 +310,7 @@ static int afs_proc_cell_vlservers_show(struct seq_file *m, void *v)
alist->preferred == i ? '>' : '-',
&alist->addrs[i].transport);
}
- seq_printf(m, " info: fl=%lx rtt=%d\n", vlserver->flags, vlserver->probe.rtt);
+ seq_printf(m, " info: fl=%lx rtt=%d\n", vlserver->flags, vlserver->rtt);
seq_printf(m, " probe: fl=%x e=%d ac=%d out=%d\n",
vlserver->probe.flags, vlserver->probe.error,
vlserver->probe.abort_code,
diff --git a/fs/afs/vl_list.c b/fs/afs/vl_list.c
index 8fea54eba0c2..38b2ba1d9ec0 100644
--- a/fs/afs/vl_list.c
+++ b/fs/afs/vl_list.c
@@ -21,6 +21,7 @@ struct afs_vlserver *afs_alloc_vlserver(const char *name, size_t name_len,
rwlock_init(&vlserver->lock);
init_waitqueue_head(&vlserver->probe_wq);
spin_lock_init(&vlserver->probe_lock);
+ vlserver->rtt = UINT_MAX;
vlserver->name_len = name_len;
vlserver->port = port;
memcpy(vlserver->name, name, name_len);
diff --git a/fs/afs/vl_probe.c b/fs/afs/vl_probe.c
index a6d04b4fbf56..d1c7068b4346 100644
--- a/fs/afs/vl_probe.c
+++ b/fs/afs/vl_probe.c
@@ -11,15 +11,33 @@
#include "internal.h"
#include "protocol_yfs.h"
-static bool afs_vl_probe_done(struct afs_vlserver *server)
+
+/*
+ * Handle the completion of a set of probes.
+ */
+static void afs_finished_vl_probe(struct afs_vlserver *server)
{
- if (!atomic_dec_and_test(&server->probe_outstanding))
- return false;
+ if (!(server->probe.flags & AFS_VLSERVER_PROBE_RESPONDED)) {
+ server->rtt = UINT_MAX;
+ clear_bit(AFS_VLSERVER_FL_RESPONDING, &server->flags);
+ }
- wake_up_var(&server->probe_outstanding);
clear_bit_unlock(AFS_VLSERVER_FL_PROBING, &server->flags);
wake_up_bit(&server->flags, AFS_VLSERVER_FL_PROBING);
- return true;
+}
+
+/*
+ * Handle the completion of a probe RPC call.
+ */
+static void afs_done_one_vl_probe(struct afs_vlserver *server, bool wake_up)
+{
+ if (atomic_dec_and_test(&server->probe_outstanding)) {
+ afs_finished_vl_probe(server);
+ wake_up = true;
+ }
+
+ if (wake_up)
+ wake_up_all(&server->probe_wq);
}
/*
@@ -52,8 +70,13 @@ void afs_vlserver_probe_result(struct afs_call *call)
goto responded;
case -ENOMEM:
case -ENONET:
+ case -EKEYEXPIRED:
+ case -EKEYREVOKED:
+ case -EKEYREJECTED:
server->probe.flags |= AFS_VLSERVER_PROBE_LOCAL_FAILURE;
- afs_io_error(call, afs_io_error_vl_probe_fail);
+ if (server->probe.error == 0)
+ server->probe.error = ret;
+ trace_afs_io_error(call->debug_id, ret, afs_io_error_vl_probe_fail);
goto out;
case -ECONNRESET: /* Responded, but call expired. */
case -ERFKILL:
@@ -72,7 +95,7 @@ void afs_vlserver_probe_result(struct afs_call *call)
server->probe.error == -ETIMEDOUT ||
server->probe.error == -ETIME))
server->probe.error = ret;
- afs_io_error(call, afs_io_error_vl_probe_fail);
+ trace_afs_io_error(call->debug_id, ret, afs_io_error_vl_probe_fail);
goto out;
}
@@ -95,22 +118,22 @@ void afs_vlserver_probe_result(struct afs_call *call)
if (rxrpc_kernel_get_srtt(call->net->socket, call->rxcall, &rtt_us) &&
rtt_us < server->probe.rtt) {
server->probe.rtt = rtt_us;
+ server->rtt = rtt_us;
alist->preferred = index;
- have_result = true;
}
smp_wmb(); /* Set rtt before responded. */
server->probe.flags |= AFS_VLSERVER_PROBE_RESPONDED;
set_bit(AFS_VLSERVER_FL_PROBED, &server->flags);
+ set_bit(AFS_VLSERVER_FL_RESPONDING, &server->flags);
+ have_result = true;
out:
spin_unlock(&server->probe_lock);
_debug("probe [%u][%u] %pISpc rtt=%u ret=%d",
server_index, index, &alist->addrs[index].transport, rtt_us, ret);
- have_result |= afs_vl_probe_done(server);
- if (have_result)
- wake_up_all(&server->probe_wq);
+ afs_done_one_vl_probe(server, have_result);
}
/*
@@ -148,11 +171,10 @@ static bool afs_do_probe_vlserver(struct afs_net *net,
in_progress = true;
} else {
afs_prioritise_error(_e, PTR_ERR(call), ac.abort_code);
+ afs_done_one_vl_probe(server, false);
}
}
- if (!in_progress)
- afs_vl_probe_done(server);
return in_progress;
}
@@ -190,7 +212,7 @@ int afs_wait_for_vl_probes(struct afs_vlserver_list *vllist,
{
struct wait_queue_entry *waits;
struct afs_vlserver *server;
- unsigned int rtt = UINT_MAX;
+ unsigned int rtt = UINT_MAX, rtt_s;
bool have_responders = false;
int pref = -1, i;
@@ -246,10 +268,11 @@ int afs_wait_for_vl_probes(struct afs_vlserver_list *vllist,
for (i = 0; i < vllist->nr_servers; i++) {
if (test_bit(i, &untried)) {
server = vllist->servers[i].server;
- if ((server->probe.flags & AFS_VLSERVER_PROBE_RESPONDED) &&
- server->probe.rtt < rtt) {
+ rtt_s = READ_ONCE(server->rtt);
+ if (test_bit(AFS_VLSERVER_FL_RESPONDING, &server->flags) &&
+ rtt_s < rtt) {
pref = i;
- rtt = server->probe.rtt;
+ rtt = rtt_s;
}
remove_wait_queue(&server->probe_wq, &waits[i]);
diff --git a/fs/afs/vl_rotate.c b/fs/afs/vl_rotate.c
index ed2609e82695..ab2beb4ba20e 100644
--- a/fs/afs/vl_rotate.c
+++ b/fs/afs/vl_rotate.c
@@ -193,7 +193,7 @@ bool afs_select_vlserver(struct afs_vl_cursor *vc)
struct afs_vlserver *s = vc->server_list->servers[i].server;
if (!test_bit(i, &vc->untried) ||
- !(s->probe.flags & AFS_VLSERVER_PROBE_RESPONDED))
+ !test_bit(AFS_VLSERVER_FL_RESPONDING, &s->flags))
continue;
if (s->probe.rtt < rtt) {
vc->index = i;
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