/*
* handle writes to /proc/fs/afs/cells
* - to add cells: echo "add <cellname> <IP>[:<IP>][:<IP>]"
*/
static int afs_proc_cells_write(struct file *file, char *buf, size_t size)
{
struct seq_file *m = file->private_data;
struct afs_net *net = afs_seq2net(m);
char *name, *args;
int ret;
/* trim to first NL */
name = memchr(buf, '\n', size);
if (name)
*name = 0;
/* split into command, name and argslist */
name = strchr(buf, ' ');
if (!name)
goto inval;
do {
*name++ = 0;
} while(*name == ' ');
if (!*name)
goto inval;
args = strchr(name, ' ');
if (args) {
do {
*args++ = 0;
} while(*args == ' ');
if (!*args)
goto inval;
}
/* determine command to perform */
_debug("cmd=%s name=%s args=%s", buf, name, args);
if (strcmp(buf, "add") == 0) {
struct afs_cell *cell;
cell = afs_lookup_cell(net, name, strlen(name), args, true);
if (IS_ERR(cell)) {
ret = PTR_ERR(cell);
goto done;
}
if (test_and_set_bit(AFS_CELL_FL_NO_GC, &cell->flags))
afs_put_cell(net, cell);
} else {
goto inval;
}
ret = 0;
done:
_leave(" = %d", ret);
return ret;
inval:
ret = -EINVAL;
printk("kAFS: Invalid Command on /proc/fs/afs/cells file\n");
goto done;
}
static void afs_destroy_sbi(struct afs_super_info *as)
{
if (as) {
afs_put_volume(as->cell, as->volume);
afs_put_cell(afs_net(as->net_ns), as->cell);
put_net(as->net_ns);
kfree(as);
}
}
/*
* parse the mount options
* - this function has been shamelessly adapted from the ext3 fs which
* shamelessly adapted it from the msdos fs
*/
static int afs_parse_options(struct afs_mount_params *params,
char *options, const char **devname)
{
struct afs_cell *cell;
substring_t args[MAX_OPT_ARGS];
char *p;
int token;
_enter("%s", options);
options[PAGE_SIZE - 1] = 0;
while ((p = strsep(&options, ","))) {
if (!*p)
continue;
token = match_token(p, afs_options_list, args);
switch (token) {
case afs_opt_cell:
rcu_read_lock();
cell = afs_lookup_cell_rcu(params->net,
args[0].from,
args[0].to - args[0].from);
rcu_read_unlock();
if (IS_ERR(cell))
return PTR_ERR(cell);
afs_put_cell(params->net, params->cell);
params->cell = cell;
break;
case afs_opt_rwpath:
params->rwpath = true;
break;
case afs_opt_vol:
*devname = args[0].from;
break;
case afs_opt_autocell:
params->autocell = true;
break;
case afs_opt_dyn:
params->dyn_root = true;
break;
default:
printk(KERN_ERR "kAFS:"
" Unknown or invalid mount option: '%s'\n", p);
return -EINVAL;
}
}
_leave(" = 0");
return 0;
}
static void afs_free_fc(struct fs_context *fc)
{
struct afs_fs_context *ctx = fc->fs_private;
afs_destroy_sbi(fc->s_fs_info);
afs_put_volume(ctx->cell, ctx->volume);
afs_put_cell(ctx->net, ctx->cell);
key_put(ctx->key);
kfree(ctx);
}
/*
* set the root cell information
* - 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, const char *rootcell)
{
struct afs_cell *old_root, *new_root;
const char *cp, *vllist;
size_t len;
_enter("");
if (!rootcell) {
/* module is loaded with no parameters, or built statically.
* - in the future we might initialize cell DB here.
*/
_leave(" = 0 [no root]");
return 0;
}
cp = strchr(rootcell, ':');
if (!cp) {
_debug("kAFS: no VL server IP addresses specified");
vllist = NULL;
len = strlen(rootcell);
} else {
vllist = cp + 1;
len = cp - rootcell;
}
/* allocate a cell record for the root cell */
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);
}
if (!test_and_set_bit(AFS_CELL_FL_NO_GC, &new_root->flags))
afs_get_cell(new_root);
/* install the new cell */
write_seqlock(&net->cells_lock);
old_root = rcu_access_pointer(net->ws_cell);
rcu_assign_pointer(net->ws_cell, new_root);
write_sequnlock(&net->cells_lock);
afs_put_cell(net, old_root);
_leave(" = 0");
return 0;
}
/*
* Purge in-memory cell database.
*/
void afs_cell_purge(struct afs_net *net)
{
struct afs_cell *ws;
_enter("");
write_seqlock(&net->cells_lock);
ws = rcu_access_pointer(net->ws_cell);
RCU_INIT_POINTER(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_var_event(&net->cells_outstanding,
!atomic_read(&net->cells_outstanding));
_leave("");
}
/*
* Parse the source name to get cell name, volume name, volume type and R/W
* selector.
*
* This can be one of the following:
* "%[cell:]volume[.]" R/W volume
* "#[cell:]volume[.]" R/O or R/W volume (R/O parent),
* or R/W (R/W parent) volume
* "%[cell:]volume.readonly" R/O volume
* "#[cell:]volume.readonly" R/O volume
* "%[cell:]volume.backup" Backup volume
* "#[cell:]volume.backup" Backup volume
*/
static int afs_parse_source(struct fs_context *fc, struct fs_parameter *param)
{
struct afs_fs_context *ctx = fc->fs_private;
struct afs_cell *cell;
const char *cellname, *suffix, *name = param->string;
int cellnamesz;
_enter(",%s", name);
if (!name) {
printk(KERN_ERR "kAFS: no volume name specified\n");
return -EINVAL;
}
if ((name[0] != '%' && name[0] != '#') || !name[1]) {
/* To use dynroot, we don't want to have to provide a source */
if (strcmp(name, "none") == 0) {
ctx->no_cell = true;
return 0;
}
printk(KERN_ERR "kAFS: unparsable volume name\n");
return -EINVAL;
}
/* determine the type of volume we're looking for */
if (name[0] == '%') {
ctx->type = AFSVL_RWVOL;
ctx->force = true;
}
name++;
/* split the cell name out if there is one */
ctx->volname = strchr(name, ':');
if (ctx->volname) {
cellname = name;
cellnamesz = ctx->volname - name;
ctx->volname++;
} else {
ctx->volname = name;
cellname = NULL;
cellnamesz = 0;
}
/* the volume type is further affected by a possible suffix */
suffix = strrchr(ctx->volname, '.');
if (suffix) {
if (strcmp(suffix, ".readonly") == 0) {
ctx->type = AFSVL_ROVOL;
ctx->force = true;
} else if (strcmp(suffix, ".backup") == 0) {
ctx->type = AFSVL_BACKVOL;
ctx->force = true;
} else if (suffix[1] == 0) {
} else {
suffix = NULL;
}
}
ctx->volnamesz = suffix ?
suffix - ctx->volname : strlen(ctx->volname);
_debug("cell %*.*s [%p]",
cellnamesz, cellnamesz, cellname ?: "", ctx->cell);
/* lookup the cell record */
if (cellname) {
cell = afs_lookup_cell(ctx->net, cellname, cellnamesz,
NULL, false);
if (IS_ERR(cell)) {
pr_err("kAFS: unable to lookup cell '%*.*s'\n",
cellnamesz, cellnamesz, cellname ?: "");
return PTR_ERR(cell);
}
afs_put_cell(ctx->net, ctx->cell);
ctx->cell = cell;
}
_debug("CELL:%s [%p] VOLUME:%*.*s SUFFIX:%s TYPE:%d%s",
ctx->cell->name, ctx->cell,
ctx->volnamesz, ctx->volnamesz, ctx->volname,
suffix ?: "-", ctx->type, ctx->force ? " FORCE" : "");
fc->source = param->string;
param->string = NULL;
return 0;
}
/*
* parse a device name to get cell name, volume name, volume type and R/W
* selector
* - this can be one of the following:
* "%[cell:]volume[.]" R/W volume
* "#[cell:]volume[.]" R/O or R/W volume (rwpath=0),
* or R/W (rwpath=1) volume
* "%[cell:]volume.readonly" R/O volume
* "#[cell:]volume.readonly" R/O volume
* "%[cell:]volume.backup" Backup volume
* "#[cell:]volume.backup" Backup volume
*/
static int afs_parse_device_name(struct afs_mount_params *params,
const char *name)
{
struct afs_cell *cell;
const char *cellname, *suffix;
int cellnamesz;
_enter(",%s", name);
if (!name) {
printk(KERN_ERR "kAFS: no volume name specified\n");
return -EINVAL;
}
if ((name[0] != '%' && name[0] != '#') || !name[1]) {
printk(KERN_ERR "kAFS: unparsable volume name\n");
return -EINVAL;
}
/* determine the type of volume we're looking for */
params->type = AFSVL_ROVOL;
params->force = false;
if (params->rwpath || name[0] == '%') {
params->type = AFSVL_RWVOL;
params->force = true;
}
name++;
/* split the cell name out if there is one */
params->volname = strchr(name, ':');
if (params->volname) {
cellname = name;
cellnamesz = params->volname - name;
params->volname++;
} else {
params->volname = name;
cellname = NULL;
cellnamesz = 0;
}
/* the volume type is further affected by a possible suffix */
suffix = strrchr(params->volname, '.');
if (suffix) {
if (strcmp(suffix, ".readonly") == 0) {
params->type = AFSVL_ROVOL;
params->force = true;
} else if (strcmp(suffix, ".backup") == 0) {
params->type = AFSVL_BACKVOL;
params->force = true;
} else if (suffix[1] == 0) {
} else {
suffix = NULL;
}
}
params->volnamesz = suffix ?
suffix - params->volname : strlen(params->volname);
_debug("cell %*.*s [%p]",
cellnamesz, cellnamesz, cellname ?: "", params->cell);
/* lookup the cell record */
if (cellname || !params->cell) {
cell = afs_cell_lookup(cellname, cellnamesz, true);
if (IS_ERR(cell)) {
printk(KERN_ERR "kAFS: unable to lookup cell '%*.*s'\n",
cellnamesz, cellnamesz, cellname ?: "");
return PTR_ERR(cell);
}
afs_put_cell(params->cell);
params->cell = cell;
}
/*
* 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);
break;
}
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));
done_seqretry(&net->cells_lock, seq);
return ret == 0 ? cell : ERR_PTR(ret);
}
/*
* afs_lookup_cell - Look up or create a cell record.
* @net: The network namespace
* @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_lookup_cell(struct afs_net *net,
const char *name, unsigned int namesz,
const char *vllist, bool excl)
{
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))
goto wait_for_cell;
}
/* 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;
}
/* 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;
}
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);
queue_work(afs_wq, &cell->manager);
wait_for_cell:
_debug("wait_for_cell");
ret = wait_on_bit(&cell->flags, AFS_CELL_FL_NOT_READY, TASK_INTERRUPTIBLE);
smp_rmb();
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]", cell);
return cell;
cell_already_exists:
_debug("cell exists");
cell = cursor;
if (excl) {
ret = -EEXIST;
} else {
afs_get_cell(cursor);
ret = 0;
}
write_sequnlock(&net->cells_lock);
kfree(candidate);
if (ret == 0)
goto wait_for_cell;
goto error_noput;
error:
afs_put_cell(net, cell);
error_noput:
_leave(" = %d [error]", ret);
return ERR_PTR(ret);
}
