blob: 700a27bc8c257e920714359ceb168d7c6d7d6055 [file] [log] [blame]
// SPDX-License-Identifier: GPL-2.0-or-later
/* Handle fileserver selection and rotation.
*
* Copyright (C) 2017 Red Hat, Inc. All Rights Reserved.
* Written by David Howells (dhowells@redhat.com)
*/
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/fs.h>
#include <linux/sched.h>
#include <linux/delay.h>
#include <linux/sched/signal.h>
#include "internal.h"
#include "afs_fs.h"
#include "protocol_uae.h"
void afs_clear_server_states(struct afs_operation *op)
{
unsigned int i;
if (op->server_states) {
for (i = 0; i < op->server_list->nr_servers; i++)
afs_put_endpoint_state(op->server_states[i].endpoint_state,
afs_estate_trace_put_server_state);
kfree(op->server_states);
}
}
/*
* Begin iteration through a server list, starting with the vnode's last used
* server if possible, or the last recorded good server if not.
*/
static bool afs_start_fs_iteration(struct afs_operation *op,
struct afs_vnode *vnode)
{
struct afs_server *server;
void *cb_server;
int i;
trace_afs_rotate(op, afs_rotate_trace_start, 0);
read_lock(&op->volume->servers_lock);
op->server_list = afs_get_serverlist(
rcu_dereference_protected(op->volume->servers,
lockdep_is_held(&op->volume->servers_lock)));
read_unlock(&op->volume->servers_lock);
op->server_states = kcalloc(op->server_list->nr_servers, sizeof(op->server_states[0]),
GFP_KERNEL);
if (!op->server_states) {
afs_op_nomem(op);
trace_afs_rotate(op, afs_rotate_trace_nomem, 0);
return false;
}
rcu_read_lock();
for (i = 0; i < op->server_list->nr_servers; i++) {
struct afs_endpoint_state *estate;
struct afs_server_state *s = &op->server_states[i];
server = op->server_list->servers[i].server;
estate = rcu_dereference(server->endpoint_state);
s->endpoint_state = afs_get_endpoint_state(estate,
afs_estate_trace_get_server_state);
s->probe_seq = estate->probe_seq;
s->untried_addrs = (1UL << estate->addresses->nr_addrs) - 1;
init_waitqueue_entry(&s->probe_waiter, current);
afs_get_address_preferences(op->net, estate->addresses);
}
rcu_read_unlock();
op->untried_servers = (1UL << op->server_list->nr_servers) - 1;
op->server_index = -1;
cb_server = vnode->cb_server;
if (cb_server) {
/* See if the vnode's preferred record is still available */
for (i = 0; i < op->server_list->nr_servers; i++) {
server = op->server_list->servers[i].server;
if (server == cb_server) {
op->server_index = i;
goto found_interest;
}
}
/* If we have a lock outstanding on a server that's no longer
* serving this vnode, then we can't switch to another server
* and have to return an error.
*/
if (op->flags & AFS_OPERATION_CUR_ONLY) {
afs_op_set_error(op, -ESTALE);
trace_afs_rotate(op, afs_rotate_trace_stale_lock, 0);
return false;
}
/* Note that the callback promise is effectively broken */
write_seqlock(&vnode->cb_lock);
ASSERTCMP(cb_server, ==, vnode->cb_server);
vnode->cb_server = NULL;
if (atomic64_xchg(&vnode->cb_expires_at, AFS_NO_CB_PROMISE) != AFS_NO_CB_PROMISE)
vnode->cb_break++;
write_sequnlock(&vnode->cb_lock);
}
found_interest:
return true;
}
/*
* Post volume busy note.
*/
static void afs_busy(struct afs_operation *op, u32 abort_code)
{
const char *m;
switch (abort_code) {
case VOFFLINE: m = "offline"; break;
case VRESTARTING: m = "restarting"; break;
case VSALVAGING: m = "being salvaged"; break;
default: m = "busy"; break;
}
pr_notice("kAFS: Volume %llu '%s' on server %pU is %s\n",
op->volume->vid, op->volume->name, &op->server->uuid, m);
}
/*
* Sleep and retry the operation to the same fileserver.
*/
static bool afs_sleep_and_retry(struct afs_operation *op)
{
trace_afs_rotate(op, afs_rotate_trace_busy_sleep, 0);
if (!(op->flags & AFS_OPERATION_UNINTR)) {
msleep_interruptible(1000);
if (signal_pending(current)) {
afs_op_set_error(op, -ERESTARTSYS);
return false;
}
} else {
msleep(1000);
}
return true;
}
/*
* Select the fileserver to use. May be called multiple times to rotate
* through the fileservers.
*/
bool afs_select_fileserver(struct afs_operation *op)
{
struct afs_addr_list *alist;
struct afs_server *server;
struct afs_vnode *vnode = op->file[0].vnode;
unsigned long set, failed;
s32 abort_code = op->call_abort_code;
int best_prio = 0;
int error = op->call_error, addr_index, i, j;
op->nr_iterations++;
_enter("OP=%x+%x,%llx,%u{%lx},%u{%lx},%d,%d",
op->debug_id, op->nr_iterations, op->volume->vid,
op->server_index, op->untried_servers,
op->addr_index, op->addr_tried,
error, abort_code);
if (op->flags & AFS_OPERATION_STOP) {
trace_afs_rotate(op, afs_rotate_trace_stopped, 0);
_leave(" = f [stopped]");
return false;
}
if (op->nr_iterations == 0)
goto start;
WRITE_ONCE(op->estate->addresses->addrs[op->addr_index].last_error, error);
trace_afs_rotate(op, afs_rotate_trace_iter, op->call_error);
/* Evaluate the result of the previous operation, if there was one. */
switch (op->call_error) {
case 0:
clear_bit(AFS_SE_VOLUME_OFFLINE,
&op->server_list->servers[op->server_index].flags);
clear_bit(AFS_SE_VOLUME_BUSY,
&op->server_list->servers[op->server_index].flags);
op->cumul_error.responded = true;
/* We succeeded, but we may need to redo the op from another
* server if we're looking at a set of RO volumes where some of
* the servers have not yet been brought up to date lest we
* regress the data. We only switch to the new version once
* >=50% of the servers are updated.
*/
error = afs_update_volume_state(op);
if (error != 0) {
if (error == 1) {
afs_sleep_and_retry(op);
goto restart_from_beginning;
}
afs_op_set_error(op, error);
goto failed;
}
fallthrough;
default:
/* Success or local failure. Stop. */
afs_op_set_error(op, error);
op->flags |= AFS_OPERATION_STOP;
trace_afs_rotate(op, afs_rotate_trace_stop, error);
_leave(" = f [okay/local %d]", error);
return false;
case -ECONNABORTED:
/* The far side rejected the operation on some grounds. This
* might involve the server being busy or the volume having been moved.
*
* Note that various V* errors should not be sent to a cache manager
* by a fileserver as they should be translated to more modern UAE*
* errors instead. IBM AFS and OpenAFS fileservers, however, do leak
* these abort codes.
*/
trace_afs_rotate(op, afs_rotate_trace_aborted, abort_code);
op->cumul_error.responded = true;
switch (abort_code) {
case VNOVOL:
/* This fileserver doesn't know about the volume.
* - May indicate that the VL is wrong - retry once and compare
* the results.
* - May indicate that the fileserver couldn't attach to the vol.
* - The volume might have been temporarily removed so that it can
* be replaced by a volume restore. "vos" might have ended one
* transaction and has yet to create the next.
* - The volume might not be blessed or might not be in-service
* (administrative action).
*/
if (op->flags & AFS_OPERATION_VNOVOL) {
afs_op_accumulate_error(op, -EREMOTEIO, abort_code);
goto next_server;
}
write_lock(&op->volume->servers_lock);
op->server_list->vnovol_mask |= 1 << op->server_index;
write_unlock(&op->volume->servers_lock);
set_bit(AFS_VOLUME_NEEDS_UPDATE, &op->volume->flags);
error = afs_check_volume_status(op->volume, op);
if (error < 0) {
afs_op_set_error(op, error);
goto failed;
}
if (test_bit(AFS_VOLUME_DELETED, &op->volume->flags)) {
afs_op_set_error(op, -ENOMEDIUM);
goto failed;
}
/* If the server list didn't change, then assume that
* it's the fileserver having trouble.
*/
if (rcu_access_pointer(op->volume->servers) == op->server_list) {
afs_op_accumulate_error(op, -EREMOTEIO, abort_code);
goto next_server;
}
/* Try again */
op->flags |= AFS_OPERATION_VNOVOL;
_leave(" = t [vnovol]");
return true;
case VVOLEXISTS:
case VONLINE:
/* These should not be returned from the fileserver. */
pr_warn("Fileserver returned unexpected abort %d\n",
abort_code);
afs_op_accumulate_error(op, -EREMOTEIO, abort_code);
goto next_server;
case VNOSERVICE:
/* Prior to AFS 3.2 VNOSERVICE was returned from the fileserver
* if the volume was neither in-service nor administratively
* blessed. All usage was replaced by VNOVOL because AFS 3.1 and
* earlier cache managers did not handle VNOSERVICE and assumed
* it was the client OSes errno 105.
*
* Starting with OpenAFS 1.4.8 VNOSERVICE was repurposed as the
* fileserver idle dead time error which was sent in place of
* RX_CALL_TIMEOUT (-3). The error was intended to be sent if the
* fileserver took too long to send a reply to the client.
* RX_CALL_TIMEOUT would have caused the cache manager to mark the
* server down whereas VNOSERVICE since AFS 3.2 would cause cache
* manager to temporarily (up to 15 minutes) mark the volume
* instance as unusable.
*
* The idle dead logic resulted in cache inconsistency since a
* state changing call that the cache manager assumed was dead
* could still be processed to completion by the fileserver. This
* logic was removed in OpenAFS 1.8.0 and VNOSERVICE is no longer
* returned. However, many 1.4.8 through 1.6.24 fileservers are
* still in existence.
*
* AuriStorFS fileservers have never returned VNOSERVICE.
*
* VNOSERVICE should be treated as an alias for RX_CALL_TIMEOUT.
*/
case RX_CALL_TIMEOUT:
afs_op_accumulate_error(op, -ETIMEDOUT, abort_code);
goto next_server;
case VSALVAGING: /* This error should not be leaked to cache managers
* but is from OpenAFS demand attach fileservers.
* It should be treated as an alias for VOFFLINE.
*/
case VSALVAGE: /* VSALVAGE should be treated as a synonym of VOFFLINE */
case VOFFLINE:
/* The volume is in use by the volserver or another volume utility
* for an operation that might alter the contents. The volume is
* expected to come back but it might take a long time (could be
* days).
*/
if (!test_and_set_bit(AFS_SE_VOLUME_OFFLINE,
&op->server_list->servers[op->server_index].flags)) {
afs_busy(op, abort_code);
clear_bit(AFS_SE_VOLUME_BUSY,
&op->server_list->servers[op->server_index].flags);
}
if (op->flags & AFS_OPERATION_NO_VSLEEP) {
afs_op_set_error(op, -EADV);
goto failed;
}
goto busy;
case VRESTARTING: /* The fileserver is either shutting down or starting up. */
case VBUSY:
/* The volume is in use by the volserver or another volume
* utility for an operation that is not expected to alter the
* contents of the volume. VBUSY does not need to be returned
* for a ROVOL or BACKVOL bound to an ITBusy volserver
* transaction. The fileserver is permitted to continue serving
* content from ROVOLs and BACKVOLs during an ITBusy transaction
* because the content will not change. However, many fileserver
* releases do return VBUSY for ROVOL and BACKVOL instances under
* many circumstances.
*
* Retry after going round all the servers unless we have a file
* lock we need to maintain.
*/
if (op->flags & AFS_OPERATION_NO_VSLEEP) {
afs_op_set_error(op, -EBUSY);
goto failed;
}
if (!test_and_set_bit(AFS_SE_VOLUME_BUSY,
&op->server_list->servers[op->server_index].flags)) {
afs_busy(op, abort_code);
clear_bit(AFS_SE_VOLUME_OFFLINE,
&op->server_list->servers[op->server_index].flags);
}
busy:
if (op->flags & AFS_OPERATION_CUR_ONLY) {
if (!afs_sleep_and_retry(op))
goto failed;
/* Retry with same server & address */
_leave(" = t [vbusy]");
return true;
}
op->flags |= AFS_OPERATION_VBUSY;
goto next_server;
case VMOVED:
/* The volume migrated to another server. We consider
* consider all locks and callbacks broken and request
* an update from the VLDB.
*
* We also limit the number of VMOVED hops we will
* honour, just in case someone sets up a loop.
*/
if (op->flags & AFS_OPERATION_VMOVED) {
afs_op_set_error(op, -EREMOTEIO);
goto failed;
}
op->flags |= AFS_OPERATION_VMOVED;
set_bit(AFS_VOLUME_WAIT, &op->volume->flags);
set_bit(AFS_VOLUME_NEEDS_UPDATE, &op->volume->flags);
error = afs_check_volume_status(op->volume, op);
if (error < 0) {
afs_op_set_error(op, error);
goto failed;
}
/* If the server list didn't change, then the VLDB is
* out of sync with the fileservers. This is hopefully
* a temporary condition, however, so we don't want to
* permanently block access to the file.
*
* TODO: Try other fileservers if we can.
*
* TODO: Retry a few times with sleeps.
*/
if (rcu_access_pointer(op->volume->servers) == op->server_list) {
afs_op_accumulate_error(op, -ENOMEDIUM, abort_code);
goto failed;
}
goto restart_from_beginning;
case UAEIO:
case VIO:
afs_op_accumulate_error(op, -EREMOTEIO, abort_code);
if (op->volume->type != AFSVL_RWVOL)
goto next_server;
goto failed;
case VDISKFULL:
case UAENOSPC:
/* The partition is full. Only applies to RWVOLs.
* Translate locally and return ENOSPC.
* No replicas to failover to.
*/
afs_op_set_error(op, -ENOSPC);
goto failed_but_online;
case VOVERQUOTA:
case UAEDQUOT:
/* Volume is full. Only applies to RWVOLs.
* Translate locally and return EDQUOT.
* No replicas to failover to.
*/
afs_op_set_error(op, -EDQUOT);
goto failed_but_online;
default:
afs_op_accumulate_error(op, error, abort_code);
failed_but_online:
clear_bit(AFS_SE_VOLUME_OFFLINE,
&op->server_list->servers[op->server_index].flags);
clear_bit(AFS_SE_VOLUME_BUSY,
&op->server_list->servers[op->server_index].flags);
goto failed;
}
case -ETIMEDOUT:
case -ETIME:
if (afs_op_error(op) != -EDESTADDRREQ)
goto iterate_address;
fallthrough;
case -ERFKILL:
case -EADDRNOTAVAIL:
case -ENETUNREACH:
case -EHOSTUNREACH:
case -EHOSTDOWN:
case -ECONNREFUSED:
_debug("no conn");
afs_op_accumulate_error(op, error, 0);
goto iterate_address;
case -ENETRESET:
pr_warn("kAFS: Peer reset %s (op=%x)\n",
op->type ? op->type->name : "???", op->debug_id);
fallthrough;
case -ECONNRESET:
_debug("call reset");
afs_op_set_error(op, error);
goto failed;
}
restart_from_beginning:
trace_afs_rotate(op, afs_rotate_trace_restart, 0);
_debug("restart");
op->estate = NULL;
op->server = NULL;
afs_clear_server_states(op);
op->server_states = NULL;
afs_put_serverlist(op->net, op->server_list);
op->server_list = NULL;
start:
_debug("start");
ASSERTCMP(op->estate, ==, NULL);
/* See if we need to do an update of the volume record. Note that the
* volume may have moved or even have been deleted.
*/
error = afs_check_volume_status(op->volume, op);
trace_afs_rotate(op, afs_rotate_trace_check_vol_status, error);
if (error < 0) {
afs_op_set_error(op, error);
goto failed;
}
if (!afs_start_fs_iteration(op, vnode))
goto failed;
_debug("__ VOL %llx __", op->volume->vid);
pick_server:
_debug("pick [%lx]", op->untried_servers);
ASSERTCMP(op->estate, ==, NULL);
error = afs_wait_for_fs_probes(op, op->server_states,
!(op->flags & AFS_OPERATION_UNINTR));
switch (error) {
case 0: /* No untried responsive servers and no outstanding probes */
trace_afs_rotate(op, afs_rotate_trace_probe_none, 0);
goto no_more_servers;
case 1: /* Got a response */
trace_afs_rotate(op, afs_rotate_trace_probe_response, 0);
break;
case 2: /* Probe data superseded */
trace_afs_rotate(op, afs_rotate_trace_probe_superseded, 0);
goto restart_from_beginning;
default:
trace_afs_rotate(op, afs_rotate_trace_probe_error, error);
afs_op_set_error(op, error);
goto failed;
}
/* Pick the untried server with the highest priority untried endpoint.
* If we have outstanding callbacks, we stick with the server we're
* already using if we can.
*/
if (op->server) {
_debug("server %u", op->server_index);
if (test_bit(op->server_index, &op->untried_servers))
goto selected_server;
op->server = NULL;
_debug("no server");
}
rcu_read_lock();
op->server_index = -1;
best_prio = -1;
for (i = 0; i < op->server_list->nr_servers; i++) {
struct afs_endpoint_state *es;
struct afs_server_entry *se = &op->server_list->servers[i];
struct afs_addr_list *sal;
struct afs_server *s = se->server;
if (!test_bit(i, &op->untried_servers) ||
test_bit(AFS_SE_EXCLUDED, &se->flags) ||
!test_bit(AFS_SERVER_FL_RESPONDING, &s->flags))
continue;
es = op->server_states->endpoint_state;
sal = es->addresses;
afs_get_address_preferences_rcu(op->net, sal);
for (j = 0; j < sal->nr_addrs; j++) {
if (!sal->addrs[j].peer)
continue;
if (sal->addrs[j].prio > best_prio) {
op->server_index = i;
best_prio = sal->addrs[j].prio;
}
}
}
rcu_read_unlock();
if (op->server_index == -1)
goto no_more_servers;
selected_server:
trace_afs_rotate(op, afs_rotate_trace_selected_server, best_prio);
_debug("use %d prio %u", op->server_index, best_prio);
__clear_bit(op->server_index, &op->untried_servers);
/* We're starting on a different fileserver from the list. We need to
* check it, create a callback intercept, find its address list and
* probe its capabilities before we use it.
*/
ASSERTCMP(op->estate, ==, NULL);
server = op->server_list->servers[op->server_index].server;
if (!afs_check_server_record(op, server, op->key))
goto failed;
_debug("USING SERVER: %pU", &server->uuid);
op->flags |= AFS_OPERATION_RETRY_SERVER;
op->server = server;
if (vnode->cb_server != server) {
vnode->cb_server = server;
vnode->cb_v_check = atomic_read(&vnode->volume->cb_v_break);
atomic64_set(&vnode->cb_expires_at, AFS_NO_CB_PROMISE);
}
retry_server:
op->addr_tried = 0;
op->addr_index = -1;
iterate_address:
/* Iterate over the current server's address list to try and find an
* address on which it will respond to us.
*/
op->estate = op->server_states[op->server_index].endpoint_state;
set = READ_ONCE(op->estate->responsive_set);
failed = READ_ONCE(op->estate->failed_set);
_debug("iterate ES=%x rs=%lx fs=%lx", op->estate->probe_seq, set, failed);
set &= ~(failed | op->addr_tried);
trace_afs_rotate(op, afs_rotate_trace_iterate_addr, set);
if (!set)
goto wait_for_more_probe_results;
alist = op->estate->addresses;
for (i = 0; i < alist->nr_addrs; i++) {
if (alist->addrs[i].prio > best_prio) {
addr_index = i;
best_prio = alist->addrs[i].prio;
}
}
addr_index = READ_ONCE(alist->preferred);
if (!test_bit(addr_index, &set))
addr_index = __ffs(set);
op->addr_index = addr_index;
set_bit(addr_index, &op->addr_tried);
op->volsync.creation = TIME64_MIN;
op->volsync.update = TIME64_MIN;
op->call_responded = false;
_debug("address [%u] %u/%u %pISp",
op->server_index, addr_index, alist->nr_addrs,
rxrpc_kernel_remote_addr(alist->addrs[op->addr_index].peer));
_leave(" = t");
return true;
wait_for_more_probe_results:
error = afs_wait_for_one_fs_probe(op->server, op->estate, op->addr_tried,
!(op->flags & AFS_OPERATION_UNINTR));
if (!error)
goto iterate_address;
/* We've now had a failure to respond on all of a server's addresses -
* immediately probe them again and consider retrying the server.
*/
trace_afs_rotate(op, afs_rotate_trace_probe_fileserver, 0);
afs_probe_fileserver(op->net, op->server);
if (op->flags & AFS_OPERATION_RETRY_SERVER) {
error = afs_wait_for_one_fs_probe(op->server, op->estate, op->addr_tried,
!(op->flags & AFS_OPERATION_UNINTR));
switch (error) {
case 0:
op->flags &= ~AFS_OPERATION_RETRY_SERVER;
trace_afs_rotate(op, afs_rotate_trace_retry_server, 0);
goto retry_server;
case -ERESTARTSYS:
afs_op_set_error(op, error);
goto failed;
case -ETIME:
case -EDESTADDRREQ:
goto next_server;
}
}
next_server:
trace_afs_rotate(op, afs_rotate_trace_next_server, 0);
_debug("next");
ASSERT(op->estate);
alist = op->estate->addresses;
if (op->call_responded &&
op->addr_index != READ_ONCE(alist->preferred) &&
test_bit(alist->preferred, &op->addr_tried))
WRITE_ONCE(alist->preferred, op->addr_index);
op->estate = NULL;
goto pick_server;
no_more_servers:
/* That's all the servers poked to no good effect. Try again if some
* of them were busy.
*/
trace_afs_rotate(op, afs_rotate_trace_no_more_servers, 0);
if (op->flags & AFS_OPERATION_VBUSY) {
afs_sleep_and_retry(op);
op->flags &= ~AFS_OPERATION_VBUSY;
goto restart_from_beginning;
}
rcu_read_lock();
for (i = 0; i < op->server_list->nr_servers; i++) {
struct afs_endpoint_state *estate;
estate = op->server_states->endpoint_state;
error = READ_ONCE(estate->error);
if (error < 0)
afs_op_accumulate_error(op, error, estate->abort_code);
}
rcu_read_unlock();
failed:
trace_afs_rotate(op, afs_rotate_trace_failed, 0);
op->flags |= AFS_OPERATION_STOP;
if (op->estate) {
alist = op->estate->addresses;
if (op->call_responded &&
op->addr_index != READ_ONCE(alist->preferred) &&
test_bit(alist->preferred, &op->addr_tried))
WRITE_ONCE(alist->preferred, op->addr_index);
op->estate = NULL;
}
_leave(" = f [failed %d]", afs_op_error(op));
return false;
}
/*
* Dump cursor state in the case of the error being EDESTADDRREQ.
*/
void afs_dump_edestaddrreq(const struct afs_operation *op)
{
static int count;
int i;
if (!IS_ENABLED(CONFIG_AFS_DEBUG_CURSOR) || count > 3)
return;
count++;
rcu_read_lock();
pr_notice("EDESTADDR occurred\n");
pr_notice("OP: cbb=%x cbb2=%x fl=%x err=%hd\n",
op->file[0].cb_break_before,
op->file[1].cb_break_before, op->flags, op->cumul_error.error);
pr_notice("OP: ut=%lx ix=%d ni=%u\n",
op->untried_servers, op->server_index, op->nr_iterations);
pr_notice("OP: call er=%d ac=%d r=%u\n",
op->call_error, op->call_abort_code, op->call_responded);
if (op->server_list) {
const struct afs_server_list *sl = op->server_list;
pr_notice("FC: SL nr=%u vnov=%hx\n",
sl->nr_servers, sl->vnovol_mask);
for (i = 0; i < sl->nr_servers; i++) {
const struct afs_server *s = sl->servers[i].server;
const struct afs_endpoint_state *e =
rcu_dereference(s->endpoint_state);
const struct afs_addr_list *a = e->addresses;
pr_notice("FC: server fl=%lx av=%u %pU\n",
s->flags, s->addr_version, &s->uuid);
pr_notice("FC: - pq=%x R=%lx F=%lx\n",
e->probe_seq, e->responsive_set, e->failed_set);
if (a) {
pr_notice("FC: - av=%u nr=%u/%u/%u pr=%u\n",
a->version,
a->nr_ipv4, a->nr_addrs, a->max_addrs,
a->preferred);
if (a == e->addresses)
pr_notice("FC: - current\n");
}
}
}
pr_notice("AC: t=%lx ax=%d\n", op->addr_tried, op->addr_index);
rcu_read_unlock();
}