/*
* Check if we have a valid request.
* Returns
* 1 if the request should continue.
* In this case we can return an autofs_wait_queue entry if one is
* found or NULL to idicate a new wait needs to be created.
* 0 or a negative errno if the request shouldn't continue.
*/
static int validate_request(struct autofs_wait_queue **wait,
struct autofs_sb_info *sbi,
struct qstr *qstr,
struct dentry*dentry, enum autofs_notify notify)
{
struct autofs_wait_queue *wq;
struct autofs_info *ino;
/* Wait in progress, continue; */
wq = autofs4_find_wait(sbi, qstr);
if (wq) {
*wait = wq;
return 1;
}
*wait = NULL;
/* If we don't yet have any info this is a new request */
ino = autofs4_dentry_ino(dentry);
if (!ino)
return 1;
/*
* If we've been asked to wait on an existing expire (NFY_NONE)
* but there is no wait in the queue ...
*/
if (notify == NFY_NONE) {
/*
* Either we've betean the pending expire to post it's
* wait or it finished while we waited on the mutex.
* So we need to wait till either, the wait appears
* or the expire finishes.
*/
while (ino->flags & AUTOFS_INF_EXPIRING) {
mutex_unlock(&sbi->wq_mutex);
schedule_timeout_interruptible(HZ/10);
if (mutex_lock_interruptible(&sbi->wq_mutex))
return -EINTR;
wq = autofs4_find_wait(sbi, qstr);
if (wq) {
*wait = wq;
return 1;
}
}
/*
* Not ideal but the status has already gone. Of the two
* cases where we wait on NFY_NONE neither depend on the
* return status of the wait.
*/
return 0;
}
/*
* If we've been asked to trigger a mount and the request
* completed while we waited on the mutex ...
*/
if (notify == NFY_MOUNT) {
/*
* If the dentry was successfully mounted while we slept
* on the wait queue mutex we can return success. If it
* isn't mounted (doesn't have submounts for the case of
* a multi-mount with no mount at it's base) we can
* continue on and create a new request.
*/
if (have_submounts(dentry))
return 0;
}
return 1;
}
int autofs4_wait(struct autofs_sb_info *sbi, struct dentry *dentry,
enum autofs_notify notify)
{
struct autofs_info *ino;
struct autofs_wait_queue *wq;
char *name;
unsigned int len = 0;
unsigned int hash = 0;
int status, type;
/* In catatonic mode, we don't wait for nobody */
if (sbi->catatonic)
return -ENOENT;
name = kmalloc(NAME_MAX + 1, GFP_KERNEL);
if (!name)
return -ENOMEM;
/* If this is a direct mount request create a dummy name */
if (IS_ROOT(tx_cache_get_dentry(dentry)) && (sbi->type & AUTOFS_TYPE_DIRECT))
len = sprintf(name, "%p", dentry);
else {
len = autofs4_getpath(sbi, dentry, &name);
if (!len) {
kfree(name);
return -ENOENT;
}
}
hash = full_name_hash(name, len);
if (mutex_lock_interruptible(&sbi->wq_mutex)) {
kfree(name);
return -EINTR;
}
wq = autofs4_find_wait(sbi, name, hash, len);
ino = autofs4_dentry_ino(dentry);
if (!wq && ino && notify == NFY_NONE) {
/*
* Either we've betean the pending expire to post it's
* wait or it finished while we waited on the mutex.
* So we need to wait till either, the wait appears
* or the expire finishes.
*/
while (ino->flags & AUTOFS_INF_EXPIRING) {
mutex_unlock(&sbi->wq_mutex);
schedule_timeout_interruptible(HZ/10);
if (mutex_lock_interruptible(&sbi->wq_mutex)) {
kfree(name);
return -EINTR;
}
wq = autofs4_find_wait(sbi, name, hash, len);
if (wq)
break;
}
/*
* Not ideal but the status has already gone. Of the two
* cases where we wait on NFY_NONE neither depend on the
* return status of the wait.
*/
if (!wq) {
kfree(name);
mutex_unlock(&sbi->wq_mutex);
return 0;
}
}
if (!wq) {
/* Create a new wait queue */
wq = kmalloc(sizeof(struct autofs_wait_queue),GFP_KERNEL);
if (!wq) {
kfree(name);
mutex_unlock(&sbi->wq_mutex);
return -ENOMEM;
}
wq->wait_queue_token = autofs4_next_wait_queue;
if (++autofs4_next_wait_queue == 0)
autofs4_next_wait_queue = 1;
wq->next = sbi->queues;
sbi->queues = wq;
init_waitqueue_head(&wq->queue);
wq->hash = hash;
wq->name = name;
wq->len = len;
wq->dev = autofs4_get_dev(sbi);
wq->ino = autofs4_get_ino(sbi);
wq->uid = current->uid;
wq->gid = current->gid;
wq->pid = current->pid;
wq->tgid = current->tgid;
wq->status = -EINTR; /* Status return if interrupted */
atomic_set(&wq->wait_ctr, 2);
mutex_unlock(&sbi->wq_mutex);
if (sbi->version < 5) {
if (notify == NFY_MOUNT)
type = autofs_ptype_missing;
else
type = autofs_ptype_expire_multi;
} else {
if (notify == NFY_MOUNT)
type = (sbi->type & AUTOFS_TYPE_DIRECT) ?
autofs_ptype_missing_direct :
autofs_ptype_missing_indirect;
else
type = (sbi->type & AUTOFS_TYPE_DIRECT) ?
autofs_ptype_expire_direct :
autofs_ptype_expire_indirect;
}
DPRINTK("new wait id = 0x%08lx, name = %.*s, nfy=%d\n",
(unsigned long) wq->wait_queue_token, wq->len, wq->name, notify);
/* autofs4_notify_daemon() may block */
autofs4_notify_daemon(sbi, wq, type);
} else {
atomic_inc(&wq->wait_ctr);
mutex_unlock(&sbi->wq_mutex);
kfree(name);
DPRINTK("existing wait id = 0x%08lx, name = %.*s, nfy=%d",
(unsigned long) wq->wait_queue_token, wq->len, wq->name, notify);
}
/* wq->name is NULL if and only if the lock is already released */
if (sbi->catatonic) {
/* We might have slept, so check again for catatonic mode */
wq->status = -ENOENT;
kfree(wq->name);
wq->name = NULL;
}
if (wq->name) {
/* Block all but "shutdown" signals while waiting */
sigset_t oldset;
unsigned long irqflags;
spin_lock_irqsave(¤t->sighand->siglock, irqflags);
oldset = current->blocked;
siginitsetinv(¤t->blocked, SHUTDOWN_SIGS & ~oldset.sig[0]);
recalc_sigpending();
spin_unlock_irqrestore(¤t->sighand->siglock, irqflags);
wait_event_interruptible(wq->queue, wq->name == NULL);
spin_lock_irqsave(¤t->sighand->siglock, irqflags);
current->blocked = oldset;
recalc_sigpending();
spin_unlock_irqrestore(¤t->sighand->siglock, irqflags);
} else {
DPRINTK("skipped sleeping");
}
status = wq->status;
/* Are we the last process to need status? */
if (atomic_dec_and_test(&wq->wait_ctr))
kfree(wq);
return status;
}
