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Commit 989782dc authored by David Howells's avatar David Howells
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afs: Overhaul cell database management 

Overhaul the way that the in-kernel AFS client keeps track of cells in the
following manner:

 (1) Cells are now held in an rbtree to make walking them quicker and RCU
     managed (though this is probably overkill).

 (2) Cells now have a manager work item that:

     (A) Looks after fetching and refreshing the VL server list.

     (B) Manages cell record lifetime, including initialising and
     	 destruction.

     (B) Manages cell record caching whereby threads are kept around for a
     	 certain time after last use and then destroyed.

     (C) Manages the FS-Cache index cookie for a cell.  It is not permitted
     	 for a cookie to be in use twice, so we have to be careful to not
     	 allow a new cell record to exist at the same time as an old record
     	 of the same name.

 (3) Each AFS network namespace is given a manager work item that manages
     the cells within it, maintaining a single timer to prod cells into
     updating their DNS records.

     This uses the reduce_timer() facility to make the timer expire at the
     soonest timed event that needs happening.

 (4) When a module is being unloaded, cells and cell managers are now
     counted out using dec_after_work() to make sure the module text is
     pinned until after the data structures have been cleaned up.

 (5) Each cell's VL server list is now protected by a seqlock rather than a
     semaphore.
Signed-off-by: default avatarDavid Howells <dhowells@redhat.com>
parent be080a6f
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Showing with 704 additions and 317 deletions
fs/afs/cell.c
View file @ 989782dc
/* AFS cell and server record management
*
* Copyright (C) 2002 Red Hat, Inc. All Rights Reserved.
* Copyright (C) 2002, 2017 Red Hat, Inc. All Rights Reserved.
* Written by David Howells (dhowells@redhat.com)
*
* This program is free software; you can redistribute it and/or
......@@ -19,128 +19,194 @@
#include <keys/rxrpc-type.h>
#include "internal.h"
unsigned __read_mostly afs_cell_gc_delay = 10;
static void afs_manage_cell(struct work_struct *);
static void afs_dec_cells_outstanding(struct afs_net *net)
{
if (atomic_dec_and_test(&net->cells_outstanding))
wake_up_atomic_t(&net->cells_outstanding);
}
/*
* allocate a cell record and fill in its name, VL server address list and
* allocate an anonymous key
* Set the cell timer to fire after a given delay, assuming it's not already
* set for an earlier time.
*/
static struct afs_cell *afs_cell_alloc(struct afs_net *net,
const char *name, unsigned namelen,
char *vllist)
static void afs_set_cell_timer(struct afs_net *net, time64_t delay)
{
struct afs_cell *cell;
struct key *key;
char keyname[4 + AFS_MAXCELLNAME + 1], *cp, *dp, *next;
char *dvllist = NULL, *_vllist = NULL;
char delimiter = ':';
int ret, i;
if (net->live) {
atomic_inc(&net->cells_outstanding);
if (timer_reduce(&net->cells_timer, jiffies + delay * HZ))
afs_dec_cells_outstanding(net);
}
}
/*
* Look up and get an activation reference on a cell record under RCU
* conditions. The caller must hold the RCU read lock.
*/
struct afs_cell *afs_lookup_cell_rcu(struct afs_net *net,
const char *name, unsigned int namesz)
{
struct afs_cell *cell = NULL;
struct rb_node *p;
int n, seq = 0, ret = 0;
_enter("%*.*s", namesz, namesz, name);
if (name && namesz == 0)
return ERR_PTR(-EINVAL);
if (namesz > AFS_MAXCELLNAME)
return ERR_PTR(-ENAMETOOLONG);
do {
/* Unfortunately, rbtree walking doesn't give reliable results
* under just the RCU read lock, so we have to check for
* changes.
*/
if (cell)
afs_put_cell(net, cell);
cell = NULL;
ret = -ENOENT;
read_seqbegin_or_lock(&net->cells_lock, &seq);
if (!name) {
cell = rcu_dereference_raw(net->ws_cell);
if (cell) {
afs_get_cell(cell);
continue;
}
ret = -EDESTADDRREQ;
continue;
}
p = rcu_dereference_raw(net->cells.rb_node);
while (p) {
cell = rb_entry(p, struct afs_cell, net_node);
n = strncasecmp(cell->name, name,
min_t(size_t, cell->name_len, namesz));
if (n == 0)
n = cell->name_len - namesz;
if (n < 0) {
p = rcu_dereference_raw(p->rb_left);
} else if (n > 0) {
p = rcu_dereference_raw(p->rb_right);
} else {
if (atomic_inc_not_zero(&cell->usage)) {
ret = 0;
break;
}
/* We want to repeat the search, this time with
* the lock properly locked.
*/
}
cell = NULL;
}
} while (need_seqretry(&net->cells_lock, seq));
_enter("%*.*s,%s", namelen, namelen, name ?: "", vllist);
done_seqretry(&net->cells_lock, seq);
BUG_ON(!name); /* TODO: want to look up "this cell" in the cache */
return ret == 0 ? cell : ERR_PTR(ret);
}
/*
* Set up a cell record and fill in its name, VL server address list and
* allocate an anonymous key
*/
static struct afs_cell *afs_alloc_cell(struct afs_net *net,
const char *name, unsigned int namelen,
const char *vllist)
{
struct afs_cell *cell;
int i, ret;
ASSERT(name);
if (namelen == 0)
return ERR_PTR(-EINVAL);
if (namelen > AFS_MAXCELLNAME) {
_leave(" = -ENAMETOOLONG");
return ERR_PTR(-ENAMETOOLONG);
}
/* allocate and initialise a cell record */
cell = kzalloc(sizeof(struct afs_cell) + namelen + 1, GFP_KERNEL);
_enter("%*.*s,%s", namelen, namelen, name, vllist);
cell = kzalloc(sizeof(struct afs_cell), GFP_KERNEL);
if (!cell) {
_leave(" = -ENOMEM");
return ERR_PTR(-ENOMEM);
}
memcpy(cell->name, name, namelen);
cell->name[namelen] = 0;
atomic_set(&cell->usage, 1);
INIT_LIST_HEAD(&cell->link);
cell->net = net;
cell->name_len = namelen;
for (i = 0; i < namelen; i++)
cell->name[i] = tolower(name[i]);
atomic_set(&cell->usage, 2);
INIT_WORK(&cell->manager, afs_manage_cell);
rwlock_init(&cell->servers_lock);
INIT_LIST_HEAD(&cell->servers);
init_rwsem(&cell->vl_sem);
INIT_LIST_HEAD(&cell->vl_list);
spin_lock_init(&cell->vl_lock);
seqlock_init(&cell->vl_addrs_lock);
cell->flags = (1 << AFS_CELL_FL_NOT_READY);
for (i = 0; i < AFS_CELL_MAX_ADDRS; i++) {
struct sockaddr_rxrpc *srx = &cell->vl_addrs[i];
srx->srx_family = AF_RXRPC;
srx->srx_service = VL_SERVICE;
srx->transport_type = SOCK_DGRAM;
srx->transport.sin.sin_port = htons(AFS_VL_PORT);
}
/* if the ip address is invalid, try dns query */
if (!vllist || strlen(vllist) < 7) {
ret = dns_query("afsdb", name, namelen, "ipv4", &dvllist, NULL);
if (ret < 0) {
if (ret == -ENODATA || ret == -EAGAIN || ret == -ENOKEY)
/* translate these errors into something
* userspace might understand */
ret = -EDESTADDRREQ;
_leave(" = %d", ret);
return ERR_PTR(ret);
srx->transport.sin6.sin6_family = AF_INET6;
srx->transport.sin6.sin6_port = htons(AFS_VL_PORT);
}
_vllist = dvllist;
/* change the delimiter for user-space reply */
delimiter = ',';
/* Fill in the VL server list if we were given a list of addresses to
* use.
*/
if (vllist) {
char delim = ':';
} else {
if (strchr(vllist, ',') || !strchr(vllist, '.'))
delimiter = ',';
_vllist = vllist;
}
delim = ',';
/* fill in the VL server list from the rest of the string */
do {
struct sockaddr_rxrpc *srx = &cell->vl_addrs[cell->vl_naddrs];
const char *end;
next = strchr(_vllist, delimiter);
if (next)
*next++ = 0;
if (in4_pton(_vllist, -1, (u8 *)&srx->transport.sin6.sin6_addr.s6_addr32[3],
-1, &end)) {
if (in4_pton(vllist, -1,
(u8 *)&srx->transport.sin6.sin6_addr.s6_addr32[3],
delim, &vllist)) {
srx->transport_len = sizeof(struct sockaddr_in6);
srx->transport.sin6.sin6_family = AF_INET6;
srx->transport.sin6.sin6_flowinfo = 0;
srx->transport.sin6.sin6_scope_id = 0;
srx->transport.sin6.sin6_addr.s6_addr32[0] = 0;
srx->transport.sin6.sin6_addr.s6_addr32[1] = 0;
srx->transport.sin6.sin6_addr.s6_addr32[2] = htonl(0xffff);
} else if (in6_pton(_vllist, -1, srx->transport.sin6.sin6_addr.s6_addr,
-1, &end)) {
} else if (in6_pton(vllist, -1,
srx->transport.sin6.sin6_addr.s6_addr,
delim, &vllist)) {
srx->transport_len = sizeof(struct sockaddr_in6);
srx->transport.sin6.sin6_family = AF_INET6;
srx->transport.sin6.sin6_flowinfo = 0;
srx->transport.sin6.sin6_scope_id = 0;
} else {
goto bad_address;
}
} while (cell->vl_naddrs++,
cell->vl_naddrs < AFS_CELL_MAX_ADDRS && (_vllist = next));
cell->vl_naddrs++;
if (!*vllist)
break;
vllist++;
/* create a key to represent an anonymous user */
memcpy(keyname, "afs@", 4);
dp = keyname + 4;
cp = cell->name;
do {
*dp++ = toupper(*cp);
} while (*cp++);
} while (cell->vl_naddrs < AFS_CELL_MAX_ADDRS && vllist);
key = rxrpc_get_null_key(keyname);
if (IS_ERR(key)) {
_debug("no key");
ret = PTR_ERR(key);
goto error;
/* Disable DNS refresh for manually-specified cells */
cell->dns_expiry = TIME64_MAX;
} else {
/* We're going to need to 'refresh' this cell's VL server list
* from the DNS before we can use it.
*/
cell->dns_expiry = S64_MIN;
}
cell->anonymous_key = key;
_debug("anon key %p{%x}",
cell->anonymous_key, key_serial(cell->anonymous_key));
_leave(" = %p", cell);
return cell;
......@@ -148,92 +214,129 @@ static struct afs_cell *afs_cell_alloc(struct afs_net *net,
bad_address:
printk(KERN_ERR "kAFS: bad VL server IP address\n");
ret = -EINVAL;
error:
key_put(cell->anonymous_key);
kfree(dvllist);
kfree(cell);
_leave(" = %d", ret);
return ERR_PTR(ret);
}
/*
* afs_cell_crate() - create a cell record
* afs_lookup_cell - Look up or create a cell record.
* @net: The network namespace
* @name: is the name of the cell.
* @namsesz: is the strlen of the cell name.
* @vllist: is a colon separated list of IP addresses in "a.b.c.d" format.
* @retref: is T to return the cell reference when the cell exists.
* @name: The name of the cell.
* @namesz: The strlen of the cell name.
* @vllist: A colon/comma separated list of numeric IP addresses or NULL.
* @excl: T if an error should be given if the cell name already exists.
*
* Look up a cell record by name and query the DNS for VL server addresses if
* needed. Note that that actual DNS query is punted off to the manager thread
* so that this function can return immediately if interrupted whilst allowing
* cell records to be shared even if not yet fully constructed.
*/
struct afs_cell *afs_cell_create(struct afs_net *net,
const char *name, unsigned namesz,
char *vllist, bool retref)
struct afs_cell *afs_lookup_cell(struct afs_net *net,
const char *name, unsigned int namesz,
const char *vllist, bool excl)
{
struct afs_cell *cell;
int ret;
_enter("%*.*s,%s", namesz, namesz, name ?: "", vllist);
struct afs_cell *cell, *candidate, *cursor;
struct rb_node *parent, **pp;
int ret, n;
_enter("%s,%s", name, vllist);
if (!excl) {
rcu_read_lock();
cell = afs_lookup_cell_rcu(net, name, namesz);
rcu_read_unlock();
if (!IS_ERR(cell)) {
if (excl) {
afs_put_cell(net, cell);
return ERR_PTR(-EEXIST);
}
goto wait_for_cell;
}
}
down_write(&net->cells_sem);
read_lock(&net->cells_lock);
list_for_each_entry(cell, &net->cells, link) {
if (strncasecmp(cell->name, name, namesz) == 0)
goto duplicate_name;
/* Assume we're probably going to create a cell and preallocate and
* mostly set up a candidate record. We can then use this to stash the
* name, the net namespace and VL server addresses.
*
* We also want to do this before we hold any locks as it may involve
* upcalling to userspace to make DNS queries.
*/
candidate = afs_alloc_cell(net, name, namesz, vllist);
if (IS_ERR(candidate)) {
_leave(" = %ld", PTR_ERR(candidate));
return candidate;
}
read_unlock(&net->cells_lock);
cell = afs_cell_alloc(net, name, namesz, vllist);
if (IS_ERR(cell)) {
_leave(" = %ld", PTR_ERR(cell));
up_write(&net->cells_sem);
return cell;
/* Find the insertion point and check to see if someone else added a
* cell whilst we were allocating.
*/
write_seqlock(&net->cells_lock);
pp = &net->cells.rb_node;
parent = NULL;
while (*pp) {
parent = *pp;
cursor = rb_entry(parent, struct afs_cell, net_node);
n = strncasecmp(cursor->name, name,
min_t(size_t, cursor->name_len, namesz));
if (n == 0)
n = cursor->name_len - namesz;
if (n < 0)
pp = &(*pp)->rb_left;
else if (n > 0)
pp = &(*pp)->rb_right;
else
goto cell_already_exists;
}
/* add a proc directory for this cell */
ret = afs_proc_cell_setup(net, cell);
if (ret < 0)
goto error;
cell = candidate;
candidate = NULL;
rb_link_node_rcu(&cell->net_node, parent, pp);
rb_insert_color(&cell->net_node, &net->cells);
atomic_inc(&net->cells_outstanding);
write_sequnlock(&net->cells_lock);
#ifdef CONFIG_AFS_FSCACHE
/* put it up for caching (this never returns an error) */
cell->cache = fscache_acquire_cookie(afs_cache_netfs.primary_index,
&afs_cell_cache_index_def,
cell, true);
#endif
queue_work(afs_wq, &cell->manager);
/* add to the cell lists */
write_lock(&net->cells_lock);
list_add_tail(&cell->link, &net->cells);
write_unlock(&net->cells_lock);
wait_for_cell:
_debug("wait_for_cell");
ret = wait_on_bit(&cell->flags, AFS_CELL_FL_NOT_READY, TASK_INTERRUPTIBLE);
smp_rmb();
down_write(&net->proc_cells_sem);
list_add_tail(&cell->proc_link, &net->proc_cells);
up_write(&net->proc_cells_sem);
up_write(&net->cells_sem);
switch (READ_ONCE(cell->state)) {
case AFS_CELL_FAILED:
ret = cell->error;
goto error;
default:
_debug("weird %u %d", cell->state, cell->error);
goto error;
case AFS_CELL_ACTIVE:
break;
}
_leave(" = %p", cell);
_leave(" = %p [cell]", cell);
return cell;
cell_already_exists:
_debug("cell exists");
cell = cursor;
if (excl) {
ret = -EEXIST;
} else {
ASSERTCMP(atomic_read(&cursor->usage), >=, 1);
afs_get_cell(cursor);
ret = 0;
}
write_sequnlock(&net->cells_lock);
kfree(candidate);
if (ret == 0)
goto wait_for_cell;
error:
up_write(&net->cells_sem);
key_put(cell->anonymous_key);
kfree(cell);
_leave(" = %d", ret);
afs_put_cell(net, cell);
_leave(" = %d [error]", ret);
return ERR_PTR(ret);
duplicate_name:
if (retref && !IS_ERR(cell))
afs_get_cell(cell);
read_unlock(&net->cells_lock);
up_write(&net->cells_sem);
if (retref) {
_leave(" = %p", cell);
return cell;
}
_leave(" = -EEXIST");
return ERR_PTR(-EEXIST);
}
/*
......@@ -241,10 +344,11 @@ struct afs_cell *afs_cell_create(struct afs_net *net,
* - can be called with a module parameter string
* - can be called from a write to /proc/fs/afs/rootcell
*/
int afs_cell_init(struct afs_net *net, char *rootcell)
int afs_cell_init(struct afs_net *net, const char *rootcell)
{
struct afs_cell *old_root, *new_root;
char *cp;
const char *cp, *vllist;
size_t len;
_enter("");
......@@ -257,223 +361,471 @@ int afs_cell_init(struct afs_net *net, char *rootcell)
}
cp = strchr(rootcell, ':');
if (!cp)
if (!cp) {
_debug("kAFS: no VL server IP addresses specified");
else
*cp++ = 0;
vllist = NULL;
len = strlen(rootcell);
} else {
vllist = cp + 1;
len = cp - rootcell;
}
/* allocate a cell record for the root cell */
new_root = afs_cell_create(net, rootcell, strlen(rootcell), cp, false);
new_root = afs_lookup_cell(net, rootcell, len, vllist, false);
if (IS_ERR(new_root)) {
_leave(" = %ld", PTR_ERR(new_root));
return PTR_ERR(new_root);
}
set_bit(AFS_CELL_FL_NO_GC, &new_root->flags);
afs_get_cell(new_root);
/* install the new cell */
write_lock(&net->cells_lock);
write_seqlock(&net->cells_lock);
old_root = net->ws_cell;
net->ws_cell = new_root;
write_unlock(&net->cells_lock);
afs_put_cell(net, old_root);
write_sequnlock(&net->cells_lock);
afs_put_cell(net, old_root);
_leave(" = 0");
return 0;
}
/*
* lookup a cell record
* Update a cell's VL server address list from the DNS.
*/
struct afs_cell *afs_cell_lookup(struct afs_net *net,
const char *name, unsigned namesz,
bool dns_cell)
static void afs_update_cell(struct afs_cell *cell)
{
struct afs_cell *cell;
time64_t now, expiry;
char *vllist = NULL;
int ret;
_enter("\"%*.*s\",", namesz, namesz, name ?: "");
_enter("%s", cell->name);
ret = dns_query("afsdb", cell->name, cell->name_len,
"ipv4", &vllist, &expiry);
_debug("query %d", ret);
switch (ret) {
case 0 ... INT_MAX:
clear_bit(AFS_CELL_FL_DNS_FAIL, &cell->flags);
clear_bit(AFS_CELL_FL_NOT_FOUND, &cell->flags);
goto parse_dns_data;
case -ENODATA:
clear_bit(AFS_CELL_FL_DNS_FAIL, &cell->flags);
set_bit(AFS_CELL_FL_NOT_FOUND, &cell->flags);
cell->dns_expiry = ktime_get_real_seconds() + 61;
cell->error = -EDESTADDRREQ;
goto out;
case -EAGAIN:
case -ECONNREFUSED:
default:
/* Unable to query DNS. */
set_bit(AFS_CELL_FL_DNS_FAIL, &cell->flags);
cell->dns_expiry = ktime_get_real_seconds() + 10;
cell->error = -EDESTADDRREQ;
goto out;
}
down_read(&net->cells_sem);
read_lock(&net->cells_lock);
parse_dns_data:
write_seqlock(&cell->vl_addrs_lock);
if (name) {
/* if the cell was named, look for it in the cell record list */
list_for_each_entry(cell, &net->cells, link) {
if (strncmp(cell->name, name, namesz) == 0) {
afs_get_cell(cell);
goto found;
}
}
cell = ERR_PTR(-ENOENT);
if (dns_cell)
goto create_cell;
found:
;
} else {
cell = net->ws_cell;
if (!cell) {
/* this should not happen unless user tries to mount
* when root cell is not set. Return an impossibly
* bizarre errno to alert the user. Things like
* ENOENT might be "more appropriate" but they happen
* for other reasons.
*/
cell = ERR_PTR(-EDESTADDRREQ);
} else {
afs_get_cell(cell);
}
ret = -EINVAL;
do {
struct sockaddr_rxrpc *srx = &cell->vl_addrs[cell->vl_naddrs];
if (in4_pton(vllist, -1,
(u8 *)&srx->transport.sin6.sin6_addr.s6_addr32[3],
',', (const char **)&vllist)) {
srx->transport_len = sizeof(struct sockaddr_in6);
srx->transport.sin6.sin6_addr.s6_addr32[0] = 0;
srx->transport.sin6.sin6_addr.s6_addr32[1] = 0;
srx->transport.sin6.sin6_addr.s6_addr32[2] = htonl(0xffff);
} else if (in6_pton(vllist, -1,
srx->transport.sin6.sin6_addr.s6_addr,
',', (const char **)&vllist)) {
srx->transport_len = sizeof(struct sockaddr_in6);
srx->transport.sin6.sin6_family = AF_INET6;
} else {
goto bad_address;
}
read_unlock(&net->cells_lock);
up_read(&net->cells_sem);
_leave(" = %p", cell);
return cell;
cell->vl_naddrs++;
if (!*vllist)
break;
vllist++;
create_cell:
read_unlock(&net->cells_lock);
up_read(&net->cells_sem);
} while (cell->vl_naddrs < AFS_CELL_MAX_ADDRS);
cell = afs_cell_create(net, name, namesz, NULL, true);
if (cell->vl_naddrs < AFS_CELL_MAX_ADDRS)
memset(cell->vl_addrs + cell->vl_naddrs, 0,
(AFS_CELL_MAX_ADDRS - cell->vl_naddrs) * sizeof(cell->vl_addrs[0]));
_leave(" = %p", cell);
return cell;
now = ktime_get_real_seconds();
cell->dns_expiry = expiry;
afs_set_cell_timer(cell->net, expiry - now);
bad_address:
write_sequnlock(&cell->vl_addrs_lock);
out:
_leave("");
}
#if 0
/*
* try and get a cell record
* Destroy a cell record
*/
struct afs_cell *afs_get_cell_maybe(struct afs_cell *cell)
static void afs_cell_destroy(struct rcu_head *rcu)
{
write_lock(&net->cells_lock);
struct afs_cell *cell = container_of(rcu, struct afs_cell, rcu);
if (cell && !list_empty(&cell->link))
afs_get_cell(cell);
else
cell = NULL;
_enter("%p{%s}", cell, cell->name);
write_unlock(&net->cells_lock);
return cell;
ASSERTCMP(atomic_read(&cell->usage), ==, 0);
key_put(cell->anonymous_key);
kfree(cell);
_leave(" [destroyed]");
}
#endif /* 0 */
/*
* destroy a cell record
* Queue the cell manager.
*/
void afs_put_cell(struct afs_net *net, struct afs_cell *cell)
static void afs_queue_cell_manager(struct afs_net *net)
{
if (!cell)
return;
int outstanding = atomic_inc_return(&net->cells_outstanding);
_enter("%p{%d,%s}", cell, atomic_read(&cell->usage), cell->name);
_enter("%d", outstanding);
ASSERTCMP(atomic_read(&cell->usage), >, 0);
if (!queue_work(afs_wq, &net->cells_manager))
afs_dec_cells_outstanding(net);
}
/* to prevent a race, the decrement and the dequeue must be effectively
* atomic */
write_lock(&net->cells_lock);
/*
* Cell management timer. We have an increment on cells_outstanding that we
* need to pass along to the work item.
*/
void afs_cells_timer(struct timer_list *timer)
{
struct afs_net *net = container_of(timer, struct afs_net, cells_timer);
if (likely(!atomic_dec_and_test(&cell->usage))) {
write_unlock(&net->cells_lock);
_leave("");
_enter("");
if (!queue_work(afs_wq, &net->cells_manager))
afs_dec_cells_outstanding(net);
}
/*
* Drop a reference on a cell record.
*/
void afs_put_cell(struct afs_net *net, struct afs_cell *cell)
{
time64_t now, expire_delay;
if (!cell)
return;
}
ASSERT(list_empty(&cell->servers));
ASSERT(list_empty(&cell->vl_list));
_enter("%s", cell->name);
wake_up(&net->cells_freeable_wq);
now = ktime_get_real_seconds();
cell->last_inactive = now;
expire_delay = 0;
if (!test_bit(AFS_CELL_FL_DNS_FAIL, &cell->flags) &&
!test_bit(AFS_CELL_FL_NOT_FOUND, &cell->flags))
expire_delay = afs_cell_gc_delay;
write_unlock(&net->cells_lock);
if (atomic_dec_return(&cell->usage) > 1)
return;
_leave(" [unused]");
/* 'cell' may now be garbage collected. */
afs_set_cell_timer(net, expire_delay);
}
/*
* destroy a cell record
* - must be called with the net->cells_sem write-locked
* - cell->link should have been broken by the caller
* Allocate a key to use as a placeholder for anonymous user security.
*/
static void afs_cell_destroy(struct afs_net *net, struct afs_cell *cell)
static int afs_alloc_anon_key(struct afs_cell *cell)
{
_enter("%p{%d,%s}", cell, atomic_read(&cell->usage), cell->name);
struct key *key;
char keyname[4 + AFS_MAXCELLNAME + 1], *cp, *dp;
ASSERTCMP(atomic_read(&cell->usage), >=, 0);
ASSERT(list_empty(&cell->link));
/* Create a key to represent an anonymous user. */
memcpy(keyname, "afs@", 4);
dp = keyname + 4;
cp = cell->name;
do {
*dp++ = tolower(*cp);
} while (*cp++);
/* wait for everyone to stop using the cell */
if (atomic_read(&cell->usage) > 0) {
DECLARE_WAITQUEUE(myself, current);
key = rxrpc_get_null_key(keyname);
if (IS_ERR(key))
return PTR_ERR(key);
_debug("wait for cell %s", cell->name);
set_current_state(TASK_UNINTERRUPTIBLE);
add_wait_queue(&net->cells_freeable_wq, &myself);
cell->anonymous_key = key;
while (atomic_read(&cell->usage) > 0) {
schedule();
set_current_state(TASK_UNINTERRUPTIBLE);
}
_debug("anon key %p{%x}",
cell->anonymous_key, key_serial(cell->anonymous_key));
return 0;
}
remove_wait_queue(&net->cells_freeable_wq, &myself);
set_current_state(TASK_RUNNING);
/*
* Activate a cell.
*/
static int afs_activate_cell(struct afs_net *net, struct afs_cell *cell)
{
int ret;
if (!cell->anonymous_key) {
ret = afs_alloc_anon_key(cell);
if (ret < 0)
return ret;
}
_debug("cell dead");
ASSERTCMP(atomic_read(&cell->usage), ==, 0);
ASSERT(list_empty(&cell->servers));
ASSERT(list_empty(&cell->vl_list));
#ifdef CONFIG_AFS_FSCACHE
cell->cache = fscache_acquire_cookie(afs_cache_netfs.primary_index,
&afs_cell_cache_index_def,
cell, true);
#endif
ret = afs_proc_cell_setup(net, cell);
if (ret < 0)
return ret;
spin_lock(&net->proc_cells_lock);
list_add_tail(&cell->proc_link, &net->proc_cells);
spin_unlock(&net->proc_cells_lock);
return 0;
}
/*
* Deactivate a cell.
*/
static void afs_deactivate_cell(struct afs_net *net, struct afs_cell *cell)
{
_enter("%s", cell->name);
afs_proc_cell_remove(net, cell);
down_write(&net->proc_cells_sem);
spin_lock(&net->proc_cells_lock);
list_del_init(&cell->proc_link);
up_write(&net->proc_cells_sem);
spin_unlock(&net->proc_cells_lock);
#ifdef CONFIG_AFS_FSCACHE
fscache_relinquish_cookie(cell->cache, 0);
cell->cache = NULL;
#endif
key_put(cell->anonymous_key);
kfree(cell);
_leave(" [destroyed]");
_leave("");
}
/*
* purge in-memory cell database on module unload or afs_init() failure
* - the timeout daemon is stopped before calling this
* Manage a cell record, initialising and destroying it, maintaining its DNS
* records.
*/
void afs_cell_purge(struct afs_net *net)
static void afs_manage_cell(struct work_struct *work)
{
struct afs_cell *cell;
struct afs_cell *cell = container_of(work, struct afs_cell, manager);
struct afs_net *net = cell->net;
bool deleted;
int ret, usage;
_enter("%s", cell->name);
again:
_debug("state %u", cell->state);
switch (cell->state) {
case AFS_CELL_INACTIVE:
case AFS_CELL_FAILED:
write_seqlock(&net->cells_lock);
usage = 1;
deleted = atomic_try_cmpxchg_relaxed(&cell->usage, &usage, 0);
if (deleted)
rb_erase(&cell->net_node, &net->cells);
write_sequnlock(&net->cells_lock);
if (deleted)
goto final_destruction;
if (cell->state == AFS_CELL_FAILED)
goto done;
cell->state = AFS_CELL_UNSET;
goto again;
case AFS_CELL_UNSET:
cell->state = AFS_CELL_ACTIVATING;
goto again;
case AFS_CELL_ACTIVATING:
ret = afs_activate_cell(net, cell);
if (ret < 0)
goto activation_failed;
cell->state = AFS_CELL_ACTIVE;
smp_wmb();
clear_bit(AFS_CELL_FL_NOT_READY, &cell->flags);
wake_up_bit(&cell->flags, AFS_CELL_FL_NOT_READY);
goto again;
case AFS_CELL_ACTIVE:
if (atomic_read(&cell->usage) > 1) {
time64_t now = ktime_get_real_seconds();
if (cell->dns_expiry <= now && net->live)
afs_update_cell(cell);
goto done;
}
cell->state = AFS_CELL_DEACTIVATING;
goto again;
case AFS_CELL_DEACTIVATING:
set_bit(AFS_CELL_FL_NOT_READY, &cell->flags);
if (atomic_read(&cell->usage) > 1)
goto reverse_deactivation;
afs_deactivate_cell(net, cell);
cell->state = AFS_CELL_INACTIVE;
goto again;
default:
break;
}
_debug("bad state %u", cell->state);
BUG(); /* Unhandled state */
activation_failed:
cell->error = ret;
afs_deactivate_cell(net, cell);
cell->state = AFS_CELL_FAILED;
smp_wmb();
if (test_and_clear_bit(AFS_CELL_FL_NOT_READY, &cell->flags))
wake_up_bit(&cell->flags, AFS_CELL_FL_NOT_READY);
goto again;
reverse_deactivation:
cell->state = AFS_CELL_ACTIVE;
smp_wmb();
clear_bit(AFS_CELL_FL_NOT_READY, &cell->flags);
wake_up_bit(&cell->flags, AFS_CELL_FL_NOT_READY);
_leave(" [deact->act]");
return;
done:
_leave(" [done %u]", cell->state);
return;
final_destruction:
call_rcu(&cell->rcu, afs_cell_destroy);
afs_dec_cells_outstanding(net);
_leave(" [destruct %d]", atomic_read(&net->cells_outstanding));
}
/*
* Manage the records of cells known to a network namespace. This includes
* updating the DNS records and garbage collecting unused cells that were
* automatically added.
*
* Note that constructed cell records may only be removed from net->cells by
* this work item, so it is safe for this work item to stash a cursor pointing
* into the tree and then return to caller (provided it skips cells that are
* still under construction).
*
* Note also that we were given an increment on net->cells_outstanding by
* whoever queued us that we need to deal with before returning.
*/
void afs_manage_cells(struct work_struct *work)
{
struct afs_net *net = container_of(work, struct afs_net, cells_manager);
struct rb_node *cursor;
time64_t now = ktime_get_real_seconds(), next_manage = TIME64_MAX;
bool purging = !net->live;
_enter("");
afs_put_cell(net, net->ws_cell);
/* Trawl the cell database looking for cells that have expired from
* lack of use and cells whose DNS results have expired and dispatch
* their managers.
*/
read_seqlock_excl(&net->cells_lock);
down_write(&net->cells_sem);
for (cursor = rb_first(&net->cells); cursor; cursor = rb_next(cursor)) {
struct afs_cell *cell =
rb_entry(cursor, struct afs_cell, net_node);
unsigned usage;
bool sched_cell = false;
while (!list_empty(&net->cells)) {
cell = NULL;
usage = atomic_read(&cell->usage);
_debug("manage %s %u", cell->name, usage);
/* remove the next cell from the front of the list */
write_lock(&net->cells_lock);
ASSERTCMP(usage, >=, 1);
if (!list_empty(&net->cells)) {
cell = list_entry(net->cells.next,
struct afs_cell, link);
list_del_init(&cell->link);
if (purging) {
if (test_and_clear_bit(AFS_CELL_FL_NO_GC, &cell->flags))
usage = atomic_dec_return(&cell->usage);
ASSERTCMP(usage, ==, 1);
}
write_unlock(&net->cells_lock);
if (usage == 1) {
time64_t expire_at = cell->last_inactive;
if (cell) {
_debug("PURGING CELL %s (%d)",
cell->name, atomic_read(&cell->usage));
if (!test_bit(AFS_CELL_FL_DNS_FAIL, &cell->flags) &&
!test_bit(AFS_CELL_FL_NOT_FOUND, &cell->flags))
expire_at += afs_cell_gc_delay;
if (purging || expire_at <= now)
sched_cell = true;
else if (expire_at < next_manage)
next_manage = expire_at;
}
/* now the cell should be left with no references */
afs_cell_destroy(net, cell);
if (!purging) {
if (cell->dns_expiry <= now)
sched_cell = true;
else if (cell->dns_expiry <= next_manage)
next_manage = cell->dns_expiry;
}
if (sched_cell)
queue_work(afs_wq, &cell->manager);
}
up_write(&net->cells_sem);
read_sequnlock_excl(&net->cells_lock);
/* Update the timer on the way out. We have to pass an increment on
* cells_outstanding in the namespace that we are in to the timer or
* the work scheduler.
*/
if (!purging && next_manage < TIME64_MAX) {
now = ktime_get_real_seconds();
if (next_manage - now <= 0) {
if (queue_work(afs_wq, &net->cells_manager))
atomic_inc(&net->cells_outstanding);
} else {
afs_set_cell_timer(net, next_manage - now);
}
}
afs_dec_cells_outstanding(net);
_leave(" [%d]", atomic_read(&net->cells_outstanding));
}
/*
* Purge in-memory cell database.
*/
void afs_cell_purge(struct afs_net *net)
{
struct afs_cell *ws;
_enter("");
write_seqlock(&net->cells_lock);
ws = net->ws_cell;
net->ws_cell = NULL;
write_sequnlock(&net->cells_lock);
afs_put_cell(net, ws);
_debug("del timer");
if (del_timer_sync(&net->cells_timer))
atomic_dec(&net->cells_outstanding);
_debug("kick mgr");
afs_queue_cell_manager(net);
_debug("wait");
wait_on_atomic_t(&net->cells_outstanding, atomic_t_wait,
TASK_UNINTERRUPTIBLE);
_leave("");
}
fs/afs/internal.h
View file @ 989782dc
......@@ -207,13 +207,14 @@ struct afs_net {
atomic_t nr_superblocks;
/* Cell database */
struct list_head cells;
struct rb_root cells;
struct afs_cell *ws_cell;
rwlock_t cells_lock;
struct rw_semaphore cells_sem;
wait_queue_head_t cells_freeable_wq;
struct work_struct cells_manager;
struct timer_list cells_timer;
atomic_t cells_outstanding;
seqlock_t cells_lock;
struct rw_semaphore proc_cells_sem;
spinlock_t proc_cells_lock;
struct list_head proc_cells;
/* Volume location database */
......@@ -242,14 +243,26 @@ struct afs_net {
extern struct afs_net __afs_net;// Dummy AFS network namespace; TODO: replace with real netns
enum afs_cell_state {
AFS_CELL_UNSET,
AFS_CELL_ACTIVATING,
AFS_CELL_ACTIVE,
AFS_CELL_DEACTIVATING,
AFS_CELL_INACTIVE,
AFS_CELL_FAILED,
};
/*
* AFS cell record
*/
struct afs_cell {
atomic_t usage;
struct list_head link; /* main cell list link */
struct afs_net *net; /* The network namespace */
union {
struct rcu_head rcu;
struct rb_node net_node; /* Node in net->cells */
};
struct afs_net *net;
struct key *anonymous_key; /* anonymous user key for this cell */
struct work_struct manager; /* Manager for init/deinit/dns */
struct list_head proc_link; /* /proc cell list link */
#ifdef CONFIG_AFS_FSCACHE
struct fscache_cookie *cache; /* caching cookie */
......@@ -262,12 +275,26 @@ struct afs_cell {
/* volume location record management */
struct rw_semaphore vl_sem; /* volume management serialisation semaphore */
struct list_head vl_list; /* cell's active VL record list */
time64_t dns_expiry; /* Time AFSDB/SRV record expires */
time64_t last_inactive; /* Time of last drop of usage count */
atomic_t usage;
unsigned long flags;
#define AFS_CELL_FL_NOT_READY 0 /* The cell record is not ready for use */
#define AFS_CELL_FL_NO_GC 1 /* The cell was added manually, don't auto-gc */
#define AFS_CELL_FL_NOT_FOUND 2 /* Permanent DNS error */
#define AFS_CELL_FL_DNS_FAIL 3 /* Failed to access DNS */
enum afs_cell_state state;
short error;
spinlock_t vl_lock; /* vl_list lock */
/* VLDB server list. */
seqlock_t vl_addrs_lock;
unsigned short vl_naddrs; /* number of VL servers in addr list */
unsigned short vl_curr_svix; /* current server index */
struct sockaddr_rxrpc vl_addrs[AFS_CELL_MAX_ADDRS]; /* cell VL server addresses */
char name[0]; /* cell name - must go last */
u8 name_len; /* Length of name */
char name[64 + 1]; /* Cell name, case-flattened and NUL-padded */
};
/*
......@@ -494,17 +521,20 @@ static inline struct afs_cb_interest *afs_get_cb_interest(struct afs_cb_interest
/*
* cell.c
*/
static inline struct afs_cell *afs_get_cell(struct afs_cell *cell)
static inline struct afs_cell *afs_get_cell(struct afs_cell *cell)
{
if (cell)
atomic_inc(&cell->usage);
return cell;
}
extern int afs_cell_init(struct afs_net *, char *);
extern struct afs_cell *afs_cell_create(struct afs_net *, const char *, unsigned, char *, bool);
extern struct afs_cell *afs_cell_lookup(struct afs_net *, const char *, unsigned, bool);
extern struct afs_cell *afs_grab_cell(struct afs_cell *);
extern int afs_cell_init(struct afs_net *, const char *);
extern struct afs_cell *afs_lookup_cell_rcu(struct afs_net *, const char *, unsigned);
extern struct afs_cell *afs_lookup_cell(struct afs_net *, const char *, unsigned,
const char *, bool);
extern void afs_put_cell(struct afs_net *, struct afs_cell *);
extern void afs_manage_cells(struct work_struct *);
extern void afs_cells_timer(struct timer_list *);
extern void __net_exit afs_cell_purge(struct afs_net *);
/*
......
fs/afs/main.c
View file @ 989782dc
......@@ -46,12 +46,15 @@ static int __net_init afs_net_init(struct afs_net *net)
INIT_WORK(&net->charge_preallocation_work, afs_charge_preallocation);
mutex_init(&net->socket_mutex);
INIT_LIST_HEAD(&net->cells);
rwlock_init(&net->cells_lock);
init_rwsem(&net->cells_sem);
init_waitqueue_head(&net->cells_freeable_wq);
init_rwsem(&net->proc_cells_sem);
net->cells = RB_ROOT;
seqlock_init(&net->cells_lock);
INIT_WORK(&net->cells_manager, afs_manage_cells);
timer_setup(&net->cells_timer, afs_cells_timer, 0);
spin_lock_init(&net->proc_cells_lock);
INIT_LIST_HEAD(&net->proc_cells);
INIT_LIST_HEAD(&net->vl_updates);
INIT_LIST_HEAD(&net->vl_graveyard);
INIT_DELAYED_WORK(&net->vl_reaper, afs_vlocation_reaper);
......@@ -83,11 +86,14 @@ static int __net_init afs_net_init(struct afs_net *net)
return 0;
error_open_socket:
net->live = false;
afs_vlocation_purge(net);
afs_cell_purge(net);
error_cell_init:
net->live = false;
afs_proc_cleanup(net);
error_proc:
net->live = false;
return ret;
}
......
fs/afs/proc.c
View file @ 989782dc
......@@ -186,7 +186,7 @@ static void *afs_proc_cells_start(struct seq_file *m, loff_t *_pos)
{
struct afs_net *net = afs_seq2net(m);
down_read(&net->proc_cells_sem);
rcu_read_lock();
return seq_list_start_head(&net->proc_cells, *_pos);
}
......@@ -205,9 +205,7 @@ static void *afs_proc_cells_next(struct seq_file *m, void *v, loff_t *pos)
*/
static void afs_proc_cells_stop(struct seq_file *m, void *v)
{
struct afs_net *net = afs_seq2net(m);
up_read(&net->proc_cells_sem);
rcu_read_unlock();
}
/*
......@@ -225,8 +223,7 @@ static int afs_proc_cells_show(struct seq_file *m, void *v)
}
/* display one cell per line on subsequent lines */
seq_printf(m, "%3d %s\n",
atomic_read(&cell->usage), cell->name);
seq_printf(m, "%3u %s\n", atomic_read(&cell->usage), cell->name);
return 0;
}
......@@ -279,13 +276,13 @@ static ssize_t afs_proc_cells_write(struct file *file, const char __user *buf,
if (strcmp(kbuf, "add") == 0) {
struct afs_cell *cell;
cell = afs_cell_create(net, name, strlen(name), args, false);
cell = afs_lookup_cell(net, name, strlen(name), args, true);
if (IS_ERR(cell)) {
ret = PTR_ERR(cell);
goto done;
}
afs_put_cell(net, cell);
set_bit(AFS_CELL_FL_NO_GC, &cell->flags);
printk("kAFS: Added new cell '%s'\n", name);
} else {
goto inval;
......@@ -354,7 +351,7 @@ int afs_proc_cell_setup(struct afs_net *net, struct afs_cell *cell)
{
struct proc_dir_entry *dir;
_enter("%p{%s}", cell, cell->name);
_enter("%p{%s},%p", cell, cell->name, net->proc_afs);
dir = proc_mkdir(cell->name, net->proc_afs);
if (!dir)
......
fs/afs/super.c
View file @ 989782dc
......@@ -200,10 +200,11 @@ static int afs_parse_options(struct afs_mount_params *params,
token = match_token(p, afs_options_list, args);
switch (token) {
case afs_opt_cell:
cell = afs_cell_lookup(params->net,
rcu_read_lock();
cell = afs_lookup_cell_rcu(params->net,
args[0].from,
args[0].to - args[0].from,
false);
args[0].to - args[0].from);
rcu_read_unlock();
if (IS_ERR(cell))
return PTR_ERR(cell);
afs_put_cell(params->net, params->cell);
......@@ -308,7 +309,8 @@ static int afs_parse_device_name(struct afs_mount_params *params,
/* lookup the cell record */
if (cellname || !params->cell) {
cell = afs_cell_lookup(params->net, cellname, cellnamesz, true);
cell = afs_lookup_cell(params->net, cellname, cellnamesz,
NULL, false);
if (IS_ERR(cell)) {
printk(KERN_ERR "kAFS: unable to lookup cell '%*.*s'\n",
cellnamesz, cellnamesz, cellname ?: "");
......
fs/afs/xattr.c
View file @ 989782dc
......@@ -45,7 +45,7 @@ static int afs_xattr_get_cell(const struct xattr_handler *handler,
struct afs_cell *cell = vnode->volume->cell;
size_t namelen;
namelen = strlen(cell->name);
namelen = cell->name_len;
if (size == 0)
return namelen;
if (namelen > size)
......
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