{
memset(req, 0, sizeof(*req));
INIT_LIST_HEAD(&req->list);
+ INIT_LIST_HEAD(&req->intr_entry);
init_waitqueue_head(&req->waitq);
atomic_set(&req->count, 1);
}
sigprocmask(SIG_SETMASK, oldset, NULL);
}
-/*
- * Reset request, so that it can be reused
- *
- * The caller must be _very_ careful to make sure, that it is holding
- * the only reference to req
- */
-void fuse_reset_request(struct fuse_req *req)
-{
- BUG_ON(atomic_read(&req->count) != 1);
- fuse_request_init(req);
-}
-
static void __fuse_get_request(struct fuse_req *req)
{
atomic_inc(&req->count);
atomic_dec(&req->count);
}
+static void fuse_req_init_context(struct fuse_req *req)
+{
+ req->in.h.uid = current->fsuid;
+ req->in.h.gid = current->fsgid;
+ req->in.h.pid = current->pid;
+}
+
struct fuse_req *fuse_get_req(struct fuse_conn *fc)
{
struct fuse_req *req;
if (intr)
goto out;
+ err = -ENOTCONN;
+ if (!fc->connected)
+ goto out;
+
req = fuse_request_alloc();
err = -ENOMEM;
if (!req)
goto out;
- req->in.h.uid = current->fsuid;
- req->in.h.gid = current->fsgid;
- req->in.h.pid = current->pid;
+ fuse_req_init_context(req);
req->waiting = 1;
return req;
return ERR_PTR(err);
}
-void fuse_put_request(struct fuse_conn *fc, struct fuse_req *req)
+/*
+ * Return request in fuse_file->reserved_req. However that may
+ * currently be in use. If that is the case, wait for it to become
+ * available.
+ */
+static struct fuse_req *get_reserved_req(struct fuse_conn *fc,
+ struct file *file)
{
- if (atomic_dec_and_test(&req->count)) {
- if (req->waiting)
- atomic_dec(&fc->num_waiting);
- fuse_request_free(req);
- }
+ struct fuse_req *req = NULL;
+ struct fuse_file *ff = file->private_data;
+
+ do {
+ wait_event(fc->blocked_waitq, ff->reserved_req);
+ spin_lock(&fc->lock);
+ if (ff->reserved_req) {
+ req = ff->reserved_req;
+ ff->reserved_req = NULL;
+ get_file(file);
+ req->stolen_file = file;
+ }
+ spin_unlock(&fc->lock);
+ } while (!req);
+
+ return req;
}
/*
- * Called with sbput_sem held for read (request_end) or write
- * (fuse_put_super). By the time fuse_put_super() is finished, all
- * inodes belonging to background requests must be released, so the
- * iputs have to be done within the locked region.
+ * Put stolen request back into fuse_file->reserved_req
*/
-void fuse_release_background(struct fuse_conn *fc, struct fuse_req *req)
+static void put_reserved_req(struct fuse_conn *fc, struct fuse_req *req)
{
- iput(req->inode);
- iput(req->inode2);
+ struct file *file = req->stolen_file;
+ struct fuse_file *ff = file->private_data;
+
spin_lock(&fc->lock);
- list_del(&req->bg_entry);
- if (fc->num_background == FUSE_MAX_BACKGROUND) {
- fc->blocked = 0;
- wake_up_all(&fc->blocked_waitq);
- }
- fc->num_background--;
+ fuse_request_init(req);
+ BUG_ON(ff->reserved_req);
+ ff->reserved_req = req;
+ wake_up(&fc->blocked_waitq);
spin_unlock(&fc->lock);
+ fput(file);
}
/*
- * This function is called when a request is finished. Either a reply
- * has arrived or it was interrupted (and not yet sent) or some error
- * occurred during communication with userspace, or the device file
- * was closed. In case of a background request the reference to the
- * stored objects are released. The requester thread is woken up (if
- * still waiting), the 'end' callback is called if given, else the
- * reference to the request is released
+ * Gets a requests for a file operation, always succeeds
*
- * Releasing extra reference for foreground requests must be done
- * within the same locked region as setting state to finished. This
- * is because fuse_reset_request() may be called after request is
- * finished and it must be the sole possessor. If request is
- * interrupted and put in the background, it will return with an error
- * and hence never be reset and reused.
+ * This is used for sending the FLUSH request, which must get to
+ * userspace, due to POSIX locks which may need to be unlocked.
*
- * Called with fc->lock, unlocks it
+ * If allocation fails due to OOM, use the reserved request in
+ * fuse_file.
+ *
+ * This is very unlikely to deadlock accidentally, since the
+ * filesystem should not have it's own file open. If deadlock is
+ * intentional, it can still be broken by "aborting" the filesystem.
*/
-static void request_end(struct fuse_conn *fc, struct fuse_req *req)
+struct fuse_req *fuse_get_req_nofail(struct fuse_conn *fc, struct file *file)
{
- list_del(&req->list);
- req->state = FUSE_REQ_FINISHED;
- if (!req->background) {
- spin_unlock(&fc->lock);
- wake_up(&req->waitq);
- fuse_put_request(fc, req);
- } else {
- void (*end) (struct fuse_conn *, struct fuse_req *) = req->end;
- req->end = NULL;
- spin_unlock(&fc->lock);
- down_read(&fc->sbput_sem);
- if (fc->mounted)
- fuse_release_background(fc, req);
- up_read(&fc->sbput_sem);
+ struct fuse_req *req;
- /* fput must go outside sbput_sem, otherwise it can deadlock */
- if (req->file)
- fput(req->file);
+ atomic_inc(&fc->num_waiting);
+ wait_event(fc->blocked_waitq, !fc->blocked);
+ req = fuse_request_alloc();
+ if (!req)
+ req = get_reserved_req(fc, file);
- if (end)
- end(fc, req);
+ fuse_req_init_context(req);
+ req->waiting = 1;
+ return req;
+}
+
+void fuse_put_request(struct fuse_conn *fc, struct fuse_req *req)
+{
+ if (atomic_dec_and_test(&req->count)) {
+ if (req->waiting)
+ atomic_dec(&fc->num_waiting);
+
+ if (req->stolen_file)
+ put_reserved_req(fc, req);
else
- fuse_put_request(fc, req);
+ fuse_request_free(req);
}
}
/*
- * Unfortunately request interruption not just solves the deadlock
- * problem, it causes problems too. These stem from the fact, that an
- * interrupted request is continued to be processed in userspace,
- * while all the locks and object references (inode and file) held
- * during the operation are released.
- *
- * To release the locks is exactly why there's a need to interrupt the
- * request, so there's not a lot that can be done about this, except
- * introduce additional locking in userspace.
- *
- * More important is to keep inode and file references until userspace
- * has replied, otherwise FORGET and RELEASE could be sent while the
- * inode/file is still used by the filesystem.
- *
- * For this reason the concept of "background" request is introduced.
- * An interrupted request is backgrounded if it has been already sent
- * to userspace. Backgrounding involves getting an extra reference to
- * inode(s) or file used in the request, and adding the request to
- * fc->background list. When a reply is received for a background
- * request, the object references are released, and the request is
- * removed from the list. If the filesystem is unmounted while there
- * are still background requests, the list is walked and references
- * are released as if a reply was received.
+ * This function is called when a request is finished. Either a reply
+ * has arrived or it was aborted (and not yet sent) or some error
+ * occurred during communication with userspace, or the device file
+ * was closed. The requester thread is woken up (if still waiting),
+ * the 'end' callback is called if given, else the reference to the
+ * request is released
*
- * There's one more use for a background request. The RELEASE message is
- * always sent as background, since it doesn't return an error or
- * data.
+ * Called with fc->lock, unlocks it
*/
-static void background_request(struct fuse_conn *fc, struct fuse_req *req)
-{
- req->background = 1;
- list_add(&req->bg_entry, &fc->background);
- fc->num_background++;
- if (fc->num_background == FUSE_MAX_BACKGROUND)
- fc->blocked = 1;
- if (req->inode)
- req->inode = igrab(req->inode);
- if (req->inode2)
- req->inode2 = igrab(req->inode2);
+static void request_end(struct fuse_conn *fc, struct fuse_req *req)
+{
+ void (*end) (struct fuse_conn *, struct fuse_req *) = req->end;
+ req->end = NULL;
+ list_del(&req->list);
+ list_del(&req->intr_entry);
+ req->state = FUSE_REQ_FINISHED;
+ if (req->background) {
+ if (fc->num_background == FUSE_MAX_BACKGROUND) {
+ fc->blocked = 0;
+ wake_up_all(&fc->blocked_waitq);
+ }
+ fc->num_background--;
+ }
+ spin_unlock(&fc->lock);
+ dput(req->dentry);
+ mntput(req->vfsmount);
if (req->file)
- get_file(req->file);
+ fput(req->file);
+ wake_up(&req->waitq);
+ if (end)
+ end(fc, req);
+ else
+ fuse_put_request(fc, req);
}
-/* Called with fc->lock held. Releases, and then reacquires it. */
-static void request_wait_answer(struct fuse_conn *fc, struct fuse_req *req)
+static void wait_answer_interruptible(struct fuse_conn *fc,
+ struct fuse_req *req)
{
- sigset_t oldset;
+ if (signal_pending(current))
+ return;
spin_unlock(&fc->lock);
- block_sigs(&oldset);
wait_event_interruptible(req->waitq, req->state == FUSE_REQ_FINISHED);
- restore_sigs(&oldset);
spin_lock(&fc->lock);
- if (req->state == FUSE_REQ_FINISHED && !req->interrupted)
- return;
+}
+
+static void queue_interrupt(struct fuse_conn *fc, struct fuse_req *req)
+{
+ list_add_tail(&req->intr_entry, &fc->interrupts);
+ wake_up(&fc->waitq);
+ kill_fasync(&fc->fasync, SIGIO, POLL_IN);
+}
+
+/* Called with fc->lock held. Releases, and then reacquires it. */
+static void request_wait_answer(struct fuse_conn *fc, struct fuse_req *req)
+{
+ if (!fc->no_interrupt) {
+ /* Any signal may interrupt this */
+ wait_answer_interruptible(fc, req);
+
+ if (req->aborted)
+ goto aborted;
+ if (req->state == FUSE_REQ_FINISHED)
+ return;
- if (!req->interrupted) {
- req->out.h.error = -EINTR;
req->interrupted = 1;
+ if (req->state == FUSE_REQ_SENT)
+ queue_interrupt(fc, req);
+ }
+
+ if (req->force) {
+ spin_unlock(&fc->lock);
+ wait_event(req->waitq, req->state == FUSE_REQ_FINISHED);
+ spin_lock(&fc->lock);
+ } else {
+ sigset_t oldset;
+
+ /* Only fatal signals may interrupt this */
+ block_sigs(&oldset);
+ wait_answer_interruptible(fc, req);
+ restore_sigs(&oldset);
}
+
+ if (req->aborted)
+ goto aborted;
+ if (req->state == FUSE_REQ_FINISHED)
+ return;
+
+ req->out.h.error = -EINTR;
+ req->aborted = 1;
+
+ aborted:
if (req->locked) {
/* This is uninterruptible sleep, because data is
being copied to/from the buffers of req. During
if (req->state == FUSE_REQ_PENDING) {
list_del(&req->list);
__fuse_put_request(req);
- } else if (req->state == FUSE_REQ_SENT)
- background_request(fc, req);
+ } else if (req->state == FUSE_REQ_SENT) {
+ spin_unlock(&fc->lock);
+ wait_event(req->waitq, req->state == FUSE_REQ_FINISHED);
+ spin_lock(&fc->lock);
+ }
}
static unsigned len_args(unsigned numargs, struct fuse_arg *args)
return nbytes;
}
+static u64 fuse_get_unique(struct fuse_conn *fc)
+ {
+ fc->reqctr++;
+ /* zero is special */
+ if (fc->reqctr == 0)
+ fc->reqctr = 1;
+
+ return fc->reqctr;
+}
+
static void queue_request(struct fuse_conn *fc, struct fuse_req *req)
{
- fc->reqctr++;
- /* zero is special */
- if (fc->reqctr == 0)
- fc->reqctr = 1;
- req->in.h.unique = fc->reqctr;
+ req->in.h.unique = fuse_get_unique(fc);
req->in.h.len = sizeof(struct fuse_in_header) +
len_args(req->in.numargs, (struct fuse_arg *) req->in.args);
list_add_tail(&req->list, &fc->pending);
kill_fasync(&fc->fasync, SIGIO, POLL_IN);
}
-/*
- * This can only be interrupted by a SIGKILL
- */
void request_send(struct fuse_conn *fc, struct fuse_req *req)
{
req->isreply = 1;
static void request_send_nowait(struct fuse_conn *fc, struct fuse_req *req)
{
spin_lock(&fc->lock);
- background_request(fc, req);
if (fc->connected) {
+ req->background = 1;
+ fc->num_background++;
+ if (fc->num_background == FUSE_MAX_BACKGROUND)
+ fc->blocked = 1;
+
queue_request(fc, req);
spin_unlock(&fc->lock);
} else {
/*
* Lock the request. Up to the next unlock_request() there mustn't be
* anything that could cause a page-fault. If the request was already
- * interrupted bail out.
+ * aborted bail out.
*/
static int lock_request(struct fuse_conn *fc, struct fuse_req *req)
{
int err = 0;
if (req) {
spin_lock(&fc->lock);
- if (req->interrupted)
+ if (req->aborted)
err = -ENOENT;
else
req->locked = 1;
}
/*
- * Unlock request. If it was interrupted during being locked, the
+ * Unlock request. If it was aborted during being locked, the
* requester thread is currently waiting for it to be unlocked, so
* wake it up.
*/
if (req) {
spin_lock(&fc->lock);
req->locked = 0;
- if (req->interrupted)
+ if (req->aborted)
wake_up(&req->waitq);
spin_unlock(&fc->lock);
}
return err;
}
+static int request_pending(struct fuse_conn *fc)
+{
+ return !list_empty(&fc->pending) || !list_empty(&fc->interrupts);
+}
+
/* Wait until a request is available on the pending list */
static void request_wait(struct fuse_conn *fc)
{
DECLARE_WAITQUEUE(wait, current);
add_wait_queue_exclusive(&fc->waitq, &wait);
- while (fc->connected && list_empty(&fc->pending)) {
+ while (fc->connected && !request_pending(fc)) {
set_current_state(TASK_INTERRUPTIBLE);
if (signal_pending(current))
break;
remove_wait_queue(&fc->waitq, &wait);
}
+/*
+ * Transfer an interrupt request to userspace
+ *
+ * Unlike other requests this is assembled on demand, without a need
+ * to allocate a separate fuse_req structure.
+ *
+ * Called with fc->lock held, releases it
+ */
+static int fuse_read_interrupt(struct fuse_conn *fc, struct fuse_req *req,
+ const struct iovec *iov, unsigned long nr_segs)
+{
+ struct fuse_copy_state cs;
+ struct fuse_in_header ih;
+ struct fuse_interrupt_in arg;
+ unsigned reqsize = sizeof(ih) + sizeof(arg);
+ int err;
+
+ list_del_init(&req->intr_entry);
+ req->intr_unique = fuse_get_unique(fc);
+ memset(&ih, 0, sizeof(ih));
+ memset(&arg, 0, sizeof(arg));
+ ih.len = reqsize;
+ ih.opcode = FUSE_INTERRUPT;
+ ih.unique = req->intr_unique;
+ arg.unique = req->in.h.unique;
+
+ spin_unlock(&fc->lock);
+ if (iov_length(iov, nr_segs) < reqsize)
+ return -EINVAL;
+
+ fuse_copy_init(&cs, fc, 1, NULL, iov, nr_segs);
+ err = fuse_copy_one(&cs, &ih, sizeof(ih));
+ if (!err)
+ err = fuse_copy_one(&cs, &arg, sizeof(arg));
+ fuse_copy_finish(&cs);
+
+ return err ? err : reqsize;
+}
+
/*
* Read a single request into the userspace filesystem's buffer. This
* function waits until a request is available, then removes it from
* the pending list and copies request data to userspace buffer. If
- * no reply is needed (FORGET) or request has been interrupted or
- * there was an error during the copying then it's finished by calling
+ * no reply is needed (FORGET) or request has been aborted or there
+ * was an error during the copying then it's finished by calling
* request_end(). Otherwise add it to the processing list, and set
* the 'sent' flag.
*/
spin_lock(&fc->lock);
err = -EAGAIN;
if ((file->f_flags & O_NONBLOCK) && fc->connected &&
- list_empty(&fc->pending))
+ !request_pending(fc))
goto err_unlock;
request_wait(fc);
if (!fc->connected)
goto err_unlock;
err = -ERESTARTSYS;
- if (list_empty(&fc->pending))
+ if (!request_pending(fc))
goto err_unlock;
+ if (!list_empty(&fc->interrupts)) {
+ req = list_entry(fc->interrupts.next, struct fuse_req,
+ intr_entry);
+ return fuse_read_interrupt(fc, req, iov, nr_segs);
+ }
+
req = list_entry(fc->pending.next, struct fuse_req, list);
req->state = FUSE_REQ_READING;
list_move(&req->list, &fc->io);
fuse_copy_finish(&cs);
spin_lock(&fc->lock);
req->locked = 0;
- if (!err && req->interrupted)
+ if (!err && req->aborted)
err = -ENOENT;
if (err) {
- if (!req->interrupted)
+ if (!req->aborted)
req->out.h.error = -EIO;
request_end(fc, req);
return err;
else {
req->state = FUSE_REQ_SENT;
list_move_tail(&req->list, &fc->processing);
+ if (req->interrupted)
+ queue_interrupt(fc, req);
spin_unlock(&fc->lock);
}
return reqsize;
list_for_each(entry, &fc->processing) {
struct fuse_req *req;
req = list_entry(entry, struct fuse_req, list);
- if (req->in.h.unique == unique)
+ if (req->in.h.unique == unique || req->intr_unique == unique)
return req;
}
return NULL;
goto err_unlock;
req = request_find(fc, oh.unique);
- err = -EINVAL;
if (!req)
goto err_unlock;
- if (req->interrupted) {
+ if (req->aborted) {
spin_unlock(&fc->lock);
fuse_copy_finish(&cs);
spin_lock(&fc->lock);
request_end(fc, req);
return -ENOENT;
}
+ /* Is it an interrupt reply? */
+ if (req->intr_unique == oh.unique) {
+ err = -EINVAL;
+ if (nbytes != sizeof(struct fuse_out_header))
+ goto err_unlock;
+
+ if (oh.error == -ENOSYS)
+ fc->no_interrupt = 1;
+ else if (oh.error == -EAGAIN)
+ queue_interrupt(fc, req);
+
+ spin_unlock(&fc->lock);
+ fuse_copy_finish(&cs);
+ return nbytes;
+ }
+
+ req->state = FUSE_REQ_WRITING;
list_move(&req->list, &fc->io);
req->out.h = oh;
req->locked = 1;
spin_lock(&fc->lock);
req->locked = 0;
if (!err) {
- if (req->interrupted)
+ if (req->aborted)
err = -ENOENT;
- } else if (!req->interrupted)
+ } else if (!req->aborted)
req->out.h.error = -EIO;
request_end(fc, req);
spin_lock(&fc->lock);
if (!fc->connected)
mask = POLLERR;
- else if (!list_empty(&fc->pending))
+ else if (request_pending(fc))
mask |= POLLIN | POLLRDNORM;
spin_unlock(&fc->lock);
/*
* Abort requests under I/O
*
- * The requests are set to interrupted and finished, and the request
+ * The requests are set to aborted and finished, and the request
* waiter is woken up. This will make request_wait_answer() wait
* until the request is unlocked and then return.
*
list_entry(fc->io.next, struct fuse_req, list);
void (*end) (struct fuse_conn *, struct fuse_req *) = req->end;
- req->interrupted = 1;
+ req->aborted = 1;
req->out.h.error = -ECONNABORTED;
req->state = FUSE_REQ_FINISHED;
list_del_init(&req->list);
* onto the pending list is prevented by req->connected being false.
*
* Progression of requests under I/O to the processing list is
- * prevented by the req->interrupted flag being true for these
- * requests. For this reason requests on the io list must be aborted
- * first.
+ * prevented by the req->aborted flag being true for these requests.
+ * For this reason requests on the io list must be aborted first.
*/
void fuse_abort_conn(struct fuse_conn *fc)
{
spin_lock(&fc->lock);
if (fc->connected) {
fc->connected = 0;
+ fc->blocked = 0;
end_io_requests(fc);
end_requests(fc, &fc->pending);
end_requests(fc, &fc->processing);
wake_up_all(&fc->waitq);
+ wake_up_all(&fc->blocked_waitq);
kill_fasync(&fc->fasync, SIGIO, POLL_IN);
}
spin_unlock(&fc->lock);
end_requests(fc, &fc->processing);
spin_unlock(&fc->lock);
fasync_helper(-1, file, 0, &fc->fasync);
- kobject_put(&fc->kobj);
+ fuse_conn_put(fc);
}
return 0;
git://git.onelab.eu / linux-2.6.git / blobdiff