mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-08-27 03:10:12 +00:00
![Gustavo A. R. Silva](/assets/img/avatar_default.png)
Replace the existing /* fall through */ comments and its variants with the new pseudo-keyword macro fallthrough[1]. Also, remove unnecessary fall-through markings when it is the case. [1] https://www.kernel.org/doc/html/v5.7/process/deprecated.html?highlight=fallthrough#implicit-switch-case-fall-through Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
513 lines
13 KiB
C
513 lines
13 KiB
C
// 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"
|
|
|
|
/*
|
|
* 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;
|
|
|
|
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->untried = (1UL << op->server_list->nr_servers) - 1;
|
|
op->index = READ_ONCE(op->server_list->preferred);
|
|
|
|
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->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) {
|
|
op->error = -ESTALE;
|
|
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 (test_and_clear_bit(AFS_VNODE_CB_PROMISED, &vnode->flags))
|
|
vnode->cb_break++;
|
|
write_sequnlock(&vnode->cb_lock);
|
|
}
|
|
|
|
found_interest:
|
|
return true;
|
|
}
|
|
|
|
/*
|
|
* Post volume busy note.
|
|
*/
|
|
static void afs_busy(struct afs_volume *volume, 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' is %s\n", volume->vid, volume->name, m);
|
|
}
|
|
|
|
/*
|
|
* Sleep and retry the operation to the same fileserver.
|
|
*/
|
|
static bool afs_sleep_and_retry(struct afs_operation *op)
|
|
{
|
|
if (!(op->flags & AFS_OPERATION_UNINTR)) {
|
|
msleep_interruptible(1000);
|
|
if (signal_pending(current)) {
|
|
op->error = -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;
|
|
struct afs_error e;
|
|
u32 rtt;
|
|
int error = op->ac.error, i;
|
|
|
|
_enter("%lx[%d],%lx[%d],%d,%d",
|
|
op->untried, op->index,
|
|
op->ac.tried, op->ac.index,
|
|
error, op->ac.abort_code);
|
|
|
|
if (op->flags & AFS_OPERATION_STOP) {
|
|
_leave(" = f [stopped]");
|
|
return false;
|
|
}
|
|
|
|
op->nr_iterations++;
|
|
|
|
/* Evaluate the result of the previous operation, if there was one. */
|
|
switch (error) {
|
|
case SHRT_MAX:
|
|
goto start;
|
|
|
|
case 0:
|
|
default:
|
|
/* Success or local failure. Stop. */
|
|
op->error = error;
|
|
op->flags |= AFS_OPERATION_STOP;
|
|
_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.
|
|
*/
|
|
switch (op->ac.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.
|
|
*/
|
|
if (op->flags & AFS_OPERATION_VNOVOL) {
|
|
op->error = -EREMOTEIO;
|
|
goto next_server;
|
|
}
|
|
|
|
write_lock(&op->volume->servers_lock);
|
|
op->server_list->vnovol_mask |= 1 << op->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)
|
|
goto failed_set_error;
|
|
|
|
if (test_bit(AFS_VOLUME_DELETED, &op->volume->flags)) {
|
|
op->error = -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) {
|
|
op->error = -EREMOTEIO;
|
|
goto next_server;
|
|
}
|
|
|
|
/* Try again */
|
|
op->flags |= AFS_OPERATION_VNOVOL;
|
|
_leave(" = t [vnovol]");
|
|
return true;
|
|
|
|
case VSALVAGE: /* TODO: Should this return an error or iterate? */
|
|
case VVOLEXISTS:
|
|
case VNOSERVICE:
|
|
case VONLINE:
|
|
case VDISKFULL:
|
|
case VOVERQUOTA:
|
|
op->error = afs_abort_to_error(op->ac.abort_code);
|
|
goto next_server;
|
|
|
|
case VOFFLINE:
|
|
if (!test_and_set_bit(AFS_VOLUME_OFFLINE, &op->volume->flags)) {
|
|
afs_busy(op->volume, op->ac.abort_code);
|
|
clear_bit(AFS_VOLUME_BUSY, &op->volume->flags);
|
|
}
|
|
if (op->flags & AFS_OPERATION_NO_VSLEEP) {
|
|
op->error = -EADV;
|
|
goto failed;
|
|
}
|
|
if (op->flags & AFS_OPERATION_CUR_ONLY) {
|
|
op->error = -ESTALE;
|
|
goto failed;
|
|
}
|
|
goto busy;
|
|
|
|
case VSALVAGING:
|
|
case VRESTARTING:
|
|
case VBUSY:
|
|
/* Retry after going round all the servers unless we
|
|
* have a file lock we need to maintain.
|
|
*/
|
|
if (op->flags & AFS_OPERATION_NO_VSLEEP) {
|
|
op->error = -EBUSY;
|
|
goto failed;
|
|
}
|
|
if (!test_and_set_bit(AFS_VOLUME_BUSY, &op->volume->flags)) {
|
|
afs_busy(op->volume, op->ac.abort_code);
|
|
clear_bit(AFS_VOLUME_OFFLINE, &op->volume->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) {
|
|
op->error = -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)
|
|
goto failed_set_error;
|
|
|
|
/* 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) {
|
|
op->error = -ENOMEDIUM;
|
|
goto failed;
|
|
}
|
|
|
|
goto restart_from_beginning;
|
|
|
|
default:
|
|
clear_bit(AFS_VOLUME_OFFLINE, &op->volume->flags);
|
|
clear_bit(AFS_VOLUME_BUSY, &op->volume->flags);
|
|
op->error = afs_abort_to_error(op->ac.abort_code);
|
|
goto failed;
|
|
}
|
|
|
|
case -ETIMEDOUT:
|
|
case -ETIME:
|
|
if (op->error != -EDESTADDRREQ)
|
|
goto iterate_address;
|
|
fallthrough;
|
|
case -ERFKILL:
|
|
case -EADDRNOTAVAIL:
|
|
case -ENETUNREACH:
|
|
case -EHOSTUNREACH:
|
|
case -EHOSTDOWN:
|
|
case -ECONNREFUSED:
|
|
_debug("no conn");
|
|
op->error = error;
|
|
goto iterate_address;
|
|
|
|
case -ECONNRESET:
|
|
_debug("call reset");
|
|
op->error = error;
|
|
goto failed;
|
|
}
|
|
|
|
restart_from_beginning:
|
|
_debug("restart");
|
|
afs_end_cursor(&op->ac);
|
|
op->server = NULL;
|
|
afs_put_serverlist(op->net, op->server_list);
|
|
op->server_list = NULL;
|
|
start:
|
|
_debug("start");
|
|
/* 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);
|
|
if (error < 0)
|
|
goto failed_set_error;
|
|
|
|
if (!afs_start_fs_iteration(op, vnode))
|
|
goto failed;
|
|
|
|
_debug("__ VOL %llx __", op->volume->vid);
|
|
|
|
pick_server:
|
|
_debug("pick [%lx]", op->untried);
|
|
|
|
error = afs_wait_for_fs_probes(op->server_list, op->untried);
|
|
if (error < 0)
|
|
goto failed_set_error;
|
|
|
|
/* Pick the untried server with the lowest RTT. If we have outstanding
|
|
* callbacks, we stick with the server we're already using if we can.
|
|
*/
|
|
if (op->server) {
|
|
_debug("server %u", op->index);
|
|
if (test_bit(op->index, &op->untried))
|
|
goto selected_server;
|
|
op->server = NULL;
|
|
_debug("no server");
|
|
}
|
|
|
|
op->index = -1;
|
|
rtt = U32_MAX;
|
|
for (i = 0; i < op->server_list->nr_servers; i++) {
|
|
struct afs_server *s = op->server_list->servers[i].server;
|
|
|
|
if (!test_bit(i, &op->untried) ||
|
|
!test_bit(AFS_SERVER_FL_RESPONDING, &s->flags))
|
|
continue;
|
|
if (s->probe.rtt < rtt) {
|
|
op->index = i;
|
|
rtt = s->probe.rtt;
|
|
}
|
|
}
|
|
|
|
if (op->index == -1)
|
|
goto no_more_servers;
|
|
|
|
selected_server:
|
|
_debug("use %d", op->index);
|
|
__clear_bit(op->index, &op->untried);
|
|
|
|
/* 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->ac.alist, ==, NULL);
|
|
server = op->server_list->servers[op->index].server;
|
|
|
|
if (!afs_check_server_record(op, server))
|
|
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_s_break = server->cb_s_break;
|
|
vnode->cb_v_break = vnode->volume->cb_v_break;
|
|
clear_bit(AFS_VNODE_CB_PROMISED, &vnode->flags);
|
|
}
|
|
|
|
read_lock(&server->fs_lock);
|
|
alist = rcu_dereference_protected(server->addresses,
|
|
lockdep_is_held(&server->fs_lock));
|
|
afs_get_addrlist(alist);
|
|
read_unlock(&server->fs_lock);
|
|
|
|
retry_server:
|
|
memset(&op->ac, 0, sizeof(op->ac));
|
|
|
|
if (!op->ac.alist)
|
|
op->ac.alist = alist;
|
|
else
|
|
afs_put_addrlist(alist);
|
|
|
|
op->ac.index = -1;
|
|
|
|
iterate_address:
|
|
ASSERT(op->ac.alist);
|
|
/* 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(&op->ac))
|
|
goto out_of_addresses;
|
|
|
|
_debug("address [%u] %u/%u %pISp",
|
|
op->index, op->ac.index, op->ac.alist->nr_addrs,
|
|
&op->ac.alist->addrs[op->ac.index].transport);
|
|
|
|
_leave(" = t");
|
|
return true;
|
|
|
|
out_of_addresses:
|
|
/* We've now had a failure to respond on all of a server's addresses -
|
|
* immediately probe them again and consider retrying the server.
|
|
*/
|
|
afs_probe_fileserver(op->net, op->server);
|
|
if (op->flags & AFS_OPERATION_RETRY_SERVER) {
|
|
alist = op->ac.alist;
|
|
error = afs_wait_for_one_fs_probe(
|
|
op->server, !(op->flags & AFS_OPERATION_UNINTR));
|
|
switch (error) {
|
|
case 0:
|
|
op->flags &= ~AFS_OPERATION_RETRY_SERVER;
|
|
goto retry_server;
|
|
case -ERESTARTSYS:
|
|
goto failed_set_error;
|
|
case -ETIME:
|
|
case -EDESTADDRREQ:
|
|
goto next_server;
|
|
}
|
|
}
|
|
|
|
next_server:
|
|
_debug("next");
|
|
afs_end_cursor(&op->ac);
|
|
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 (op->flags & AFS_OPERATION_VBUSY)
|
|
goto restart_from_beginning;
|
|
|
|
e.error = -EDESTADDRREQ;
|
|
e.responded = false;
|
|
for (i = 0; i < op->server_list->nr_servers; i++) {
|
|
struct afs_server *s = op->server_list->servers[i].server;
|
|
|
|
afs_prioritise_error(&e, READ_ONCE(s->probe.error),
|
|
s->probe.abort_code);
|
|
}
|
|
|
|
error = e.error;
|
|
|
|
failed_set_error:
|
|
op->error = error;
|
|
failed:
|
|
op->flags |= AFS_OPERATION_STOP;
|
|
afs_end_cursor(&op->ac);
|
|
_leave(" = f [failed %d]", op->error);
|
|
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("FC: cbb=%x cbb2=%x fl=%x err=%hd\n",
|
|
op->file[0].cb_break_before,
|
|
op->file[1].cb_break_before, op->flags, op->error);
|
|
pr_notice("FC: ut=%lx ix=%d ni=%u\n",
|
|
op->untried, op->index, op->nr_iterations);
|
|
|
|
if (op->server_list) {
|
|
const struct afs_server_list *sl = op->server_list;
|
|
pr_notice("FC: SL nr=%u pr=%u vnov=%hx\n",
|
|
sl->nr_servers, sl->preferred, sl->vnovol_mask);
|
|
for (i = 0; i < sl->nr_servers; i++) {
|
|
const struct afs_server *s = sl->servers[i].server;
|
|
pr_notice("FC: server fl=%lx av=%u %pU\n",
|
|
s->flags, s->addr_version, &s->uuid);
|
|
if (s->addresses) {
|
|
const struct afs_addr_list *a =
|
|
rcu_dereference(s->addresses);
|
|
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);
|
|
pr_notice("FC: - R=%lx F=%lx\n",
|
|
a->responded, a->failed);
|
|
if (a == op->ac.alist)
|
|
pr_notice("FC: - current\n");
|
|
}
|
|
}
|
|
}
|
|
|
|
pr_notice("AC: t=%lx ax=%u ac=%d er=%d r=%u ni=%u\n",
|
|
op->ac.tried, op->ac.index, op->ac.abort_code, op->ac.error,
|
|
op->ac.responded, op->ac.nr_iterations);
|
|
rcu_read_unlock();
|
|
}
|