Merge tag 'fuse-update-5.4' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuse

Pull fuse updates from Miklos Szeredi:

 - Continue separating the transport (user/kernel communication) and the
   filesystem layers of fuse. Getting rid of most layering violations
   will allow for easier cleanup and optimization later on.

 - Prepare for the addition of the virtio-fs filesystem. The actual
   filesystem will be introduced by a separate pull request.

 - Convert to new mount API.

 - Various fixes, optimizations and cleanups.

* tag 'fuse-update-5.4' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuse: (55 commits)
  fuse: Make fuse_args_to_req static
  fuse: fix memleak in cuse_channel_open
  fuse: fix beyond-end-of-page access in fuse_parse_cache()
  fuse: unexport fuse_put_request
  fuse: kmemcg account fs data
  fuse: on 64-bit store time in d_fsdata directly
  fuse: fix missing unlock_page in fuse_writepage()
  fuse: reserve byteswapped init opcodes
  fuse: allow skipping control interface and forced unmount
  fuse: dissociate DESTROY from fuseblk
  fuse: delete dentry if timeout is zero
  fuse: separate fuse device allocation and installation in fuse_conn
  fuse: add fuse_iqueue_ops callbacks
  fuse: extract fuse_fill_super_common()
  fuse: export fuse_dequeue_forget() function
  fuse: export fuse_get_unique()
  fuse: export fuse_send_init_request()
  fuse: export fuse_len_args()
  fuse: export fuse_end_request()
  fuse: fix request limit
  ...

fs/fs_context.c

@@ -504,7 +504,6 @@ void put_fs_context(struct fs_context *fc)
 	put_net(fc->net_ns);
 	put_user_ns(fc->user_ns);
 	put_cred(fc->cred);
-	kfree(fc->subtype);
 	put_fc_log(fc);
 	put_filesystem(fc->fs_type);
 	kfree(fc->source);
@@ -571,17 +570,6 @@ static int legacy_parse_param(struct fs_context *fc, struct fs_parameter *param)
 		return 0;
 	}
 
-	if ((fc->fs_type->fs_flags & FS_HAS_SUBTYPE) &&
-	    strcmp(param->key, "subtype") == 0) {
-		if (param->type != fs_value_is_string)
-			return invalf(fc, "VFS: Legacy: Non-string subtype");
-		if (fc->subtype)
-			return invalf(fc, "VFS: Legacy: Multiple subtype");
-		fc->subtype = param->string;
-		param->string = NULL;
-		return 0;
-	}
-
 	if (ctx->param_type == LEGACY_FS_MONOLITHIC_PARAMS)
 		return invalf(fc, "VFS: Legacy: Can't mix monolithic and individual options");
 
@@ -738,8 +726,6 @@ void vfs_clean_context(struct fs_context *fc)
 	fc->s_fs_info = NULL;
 	fc->sb_flags = 0;
 	security_free_mnt_opts(&fc->security);
-	kfree(fc->subtype);
-	fc->subtype = NULL;
 	kfree(fc->source);
 	fc->source = NULL;
 

fs/fuse/cuse.c

@@ -142,11 +142,10 @@ static int cuse_open(struct inode *inode, struct file *file)
 
 static int cuse_release(struct inode *inode, struct file *file)
 {
-	struct fuse_inode *fi = get_fuse_inode(inode);
 	struct fuse_file *ff = file->private_data;
 	struct fuse_conn *fc = ff->fc;
 
-	fuse_sync_release(fi, ff, file->f_flags);
+	fuse_sync_release(NULL, ff, file->f_flags);
 	fuse_conn_put(fc);
 
 	return 0;
@@ -299,6 +298,14 @@ static void cuse_gendev_release(struct device *dev)
 	kfree(dev);
 }
 
+struct cuse_init_args {
+	struct fuse_args_pages ap;
+	struct cuse_init_in in;
+	struct cuse_init_out out;
+	struct page *page;
+	struct fuse_page_desc desc;
+};
+
 /**
  * cuse_process_init_reply - finish initializing CUSE channel
  *
@@ -306,21 +313,22 @@ static void cuse_gendev_release(struct device *dev)
  * required data structures for it.  Please read the comment at the
  * top of this file for high level overview.
  */
-static void cuse_process_init_reply(struct fuse_conn *fc, struct fuse_req *req)
+static void cuse_process_init_reply(struct fuse_conn *fc,
+				    struct fuse_args *args, int error)
 {
+	struct cuse_init_args *ia = container_of(args, typeof(*ia), ap.args);
+	struct fuse_args_pages *ap = &ia->ap;
 	struct cuse_conn *cc = fc_to_cc(fc), *pos;
-	struct cuse_init_out *arg = req->out.args[0].value;
-	struct page *page = req->pages[0];
+	struct cuse_init_out *arg = &ia->out;
+	struct page *page = ap->pages[0];
 	struct cuse_devinfo devinfo = { };
 	struct device *dev;
 	struct cdev *cdev;
 	dev_t devt;
 	int rc, i;
 
-	if (req->out.h.error ||
-	    arg->major != FUSE_KERNEL_VERSION || arg->minor < 11) {
+	if (error || arg->major != FUSE_KERNEL_VERSION || arg->minor < 11)
 		goto err;
-	}
 
 	fc->minor = arg->minor;
 	fc->max_read = max_t(unsigned, arg->max_read, 4096);
@@ -329,7 +337,7 @@ static void cuse_process_init_reply(struct fuse_conn *fc, struct fuse_req *req)
 	/* parse init reply */
 	cc->unrestricted_ioctl = arg->flags & CUSE_UNRESTRICTED_IOCTL;
 
-	rc = cuse_parse_devinfo(page_address(page), req->out.args[1].size,
+	rc = cuse_parse_devinfo(page_address(page), ap->args.out_args[1].size,
 				&devinfo);
 	if (rc)
 		goto err;
@@ -396,7 +404,7 @@ static void cuse_process_init_reply(struct fuse_conn *fc, struct fuse_req *req)
 	dev_set_uevent_suppress(dev, 0);
 	kobject_uevent(&dev->kobj, KOBJ_ADD);
 out:
-	kfree(arg);
+	kfree(ia);
 	__free_page(page);
 	return;
 
@@ -415,55 +423,49 @@ static void cuse_process_init_reply(struct fuse_conn *fc, struct fuse_req *req)
 static int cuse_send_init(struct cuse_conn *cc)
 {
 	int rc;
-	struct fuse_req *req;
 	struct page *page;
 	struct fuse_conn *fc = &cc->fc;
-	struct cuse_init_in *arg;
-	void *outarg;
+	struct cuse_init_args *ia;
+	struct fuse_args_pages *ap;
 
 	BUILD_BUG_ON(CUSE_INIT_INFO_MAX > PAGE_SIZE);
 
-	req = fuse_get_req_for_background(fc, 1);
-	if (IS_ERR(req)) {
-		rc = PTR_ERR(req);
-		goto err;
-	}
-
 	rc = -ENOMEM;
 	page = alloc_page(GFP_KERNEL | __GFP_ZERO);
 	if (!page)
-		goto err_put_req;
+		goto err;
 
-	outarg = kzalloc(sizeof(struct cuse_init_out), GFP_KERNEL);
-	if (!outarg)
+	ia = kzalloc(sizeof(*ia), GFP_KERNEL);
+	if (!ia)
 		goto err_free_page;
 
-	arg = &req->misc.cuse_init_in;
-	arg->major = FUSE_KERNEL_VERSION;
-	arg->minor = FUSE_KERNEL_MINOR_VERSION;
-	arg->flags |= CUSE_UNRESTRICTED_IOCTL;
-	req->in.h.opcode = CUSE_INIT;
-	req->in.numargs = 1;
-	req->in.args[0].size = sizeof(struct cuse_init_in);
-	req->in.args[0].value = arg;
-	req->out.numargs = 2;
-	req->out.args[0].size = sizeof(struct cuse_init_out);
-	req->out.args[0].value = outarg;
-	req->out.args[1].size = CUSE_INIT_INFO_MAX;
-	req->out.argvar = 1;
-	req->out.argpages = 1;
-	req->pages[0] = page;
-	req->page_descs[0].length = req->out.args[1].size;
-	req->num_pages = 1;
-	req->end = cuse_process_init_reply;
-	fuse_request_send_background(fc, req);
-
-	return 0;
-
+	ap = &ia->ap;
+	ia->in.major = FUSE_KERNEL_VERSION;
+	ia->in.minor = FUSE_KERNEL_MINOR_VERSION;
+	ia->in.flags |= CUSE_UNRESTRICTED_IOCTL;
+	ap->args.opcode = CUSE_INIT;
+	ap->args.in_numargs = 1;
+	ap->args.in_args[0].size = sizeof(ia->in);
+	ap->args.in_args[0].value = &ia->in;
+	ap->args.out_numargs = 2;
+	ap->args.out_args[0].size = sizeof(ia->out);
+	ap->args.out_args[0].value = &ia->out;
+	ap->args.out_args[1].size = CUSE_INIT_INFO_MAX;
+	ap->args.out_argvar = 1;
+	ap->args.out_pages = 1;
+	ap->num_pages = 1;
+	ap->pages = &ia->page;
+	ap->descs = &ia->desc;
+	ia->page = page;
+	ia->desc.length = ap->args.out_args[1].size;
+	ap->args.end = cuse_process_init_reply;
+
+	rc = fuse_simple_background(fc, &ap->args, GFP_KERNEL);
+	if (rc) {
+		kfree(ia);
 err_free_page:
-	__free_page(page);
-err_put_req:
-	fuse_put_request(fc, req);
+		__free_page(page);
+	}
 err:
 	return rc;
 }
@@ -504,9 +506,9 @@ static int cuse_channel_open(struct inode *inode, struct file *file)
 	 * Limit the cuse channel to requests that can
 	 * be represented in file->f_cred->user_ns.
 	 */
-	fuse_conn_init(&cc->fc, file->f_cred->user_ns);
+	fuse_conn_init(&cc->fc, file->f_cred->user_ns, &fuse_dev_fiq_ops, NULL);
 
-	fud = fuse_dev_alloc(&cc->fc);
+	fud = fuse_dev_alloc_install(&cc->fc);
 	if (!fud) {
 		kfree(cc);
 		return -ENOMEM;
@@ -519,6 +521,7 @@ static int cuse_channel_open(struct inode *inode, struct file *file)
 	rc = cuse_send_init(cc);
 	if (rc) {
 		fuse_dev_free(fud);
+		fuse_conn_put(&cc->fc);
 		return rc;
 	}
 	file->private_data = fud;

fs/fuse/dev.c

@@ -40,107 +40,30 @@ static struct fuse_dev *fuse_get_dev(struct file *file)
 	return READ_ONCE(file->private_data);
 }
 
-static void fuse_request_init(struct fuse_req *req, struct page **pages,
-			      struct fuse_page_desc *page_descs,
-			      unsigned npages)
+static void fuse_request_init(struct fuse_req *req)
 {
 	INIT_LIST_HEAD(&req->list);
 	INIT_LIST_HEAD(&req->intr_entry);
 	init_waitqueue_head(&req->waitq);
 	refcount_set(&req->count, 1);
-	req->pages = pages;
-	req->page_descs = page_descs;
-	req->max_pages = npages;
 	__set_bit(FR_PENDING, &req->flags);
 }
 
-static struct page **fuse_req_pages_alloc(unsigned int npages, gfp_t flags,
-					  struct fuse_page_desc **desc)
-{
-	struct page **pages;
-
-	pages = kzalloc(npages * (sizeof(struct page *) +
-				  sizeof(struct fuse_page_desc)), flags);
-	*desc = (void *) pages + npages * sizeof(struct page *);
-
-	return pages;
-}
-
-static struct fuse_req *__fuse_request_alloc(unsigned npages, gfp_t flags)
+static struct fuse_req *fuse_request_alloc(gfp_t flags)
 {
 	struct fuse_req *req = kmem_cache_zalloc(fuse_req_cachep, flags);
-	if (req) {
-		struct page **pages = NULL;
-		struct fuse_page_desc *page_descs = NULL;
-
-		WARN_ON(npages > FUSE_MAX_MAX_PAGES);
-		if (npages > FUSE_REQ_INLINE_PAGES) {
-			pages = fuse_req_pages_alloc(npages, flags,
-						     &page_descs);
-			if (!pages) {
-				kmem_cache_free(fuse_req_cachep, req);
-				return NULL;
-			}
-		} else if (npages) {
-			pages = req->inline_pages;
-			page_descs = req->inline_page_descs;
-		}
+	if (req)
+		fuse_request_init(req);
 
-		fuse_request_init(req, pages, page_descs, npages);
-	}
 	return req;
 }
 
-struct fuse_req *fuse_request_alloc(unsigned npages)
-{
-	return __fuse_request_alloc(npages, GFP_KERNEL);
-}
-EXPORT_SYMBOL_GPL(fuse_request_alloc);
-
-struct fuse_req *fuse_request_alloc_nofs(unsigned npages)
-{
-	return __fuse_request_alloc(npages, GFP_NOFS);
-}
-
-static void fuse_req_pages_free(struct fuse_req *req)
-{
-	if (req->pages != req->inline_pages)
-		kfree(req->pages);
-}
-
-bool fuse_req_realloc_pages(struct fuse_conn *fc, struct fuse_req *req,
-			    gfp_t flags)
-{
-	struct page **pages;
-	struct fuse_page_desc *page_descs;
-	unsigned int npages = min_t(unsigned int,
-				    max_t(unsigned int, req->max_pages * 2,
-					  FUSE_DEFAULT_MAX_PAGES_PER_REQ),
-				    fc->max_pages);
-	WARN_ON(npages <= req->max_pages);
-
-	pages = fuse_req_pages_alloc(npages, flags, &page_descs);
-	if (!pages)
-		return false;
-
-	memcpy(pages, req->pages, sizeof(struct page *) * req->max_pages);
-	memcpy(page_descs, req->page_descs,
-	       sizeof(struct fuse_page_desc) * req->max_pages);
-	fuse_req_pages_free(req);
-	req->pages = pages;
-	req->page_descs = page_descs;
-	req->max_pages = npages;
-
-	return true;
-}
-
-void fuse_request_free(struct fuse_req *req)
+static void fuse_request_free(struct fuse_req *req)
 {
-	fuse_req_pages_free(req);
 	kmem_cache_free(fuse_req_cachep, req);
 }
 
-void __fuse_get_request(struct fuse_req *req)
+static void __fuse_get_request(struct fuse_req *req)
 {
 	refcount_inc(&req->count);
 }
@@ -177,8 +100,9 @@ static void fuse_drop_waiting(struct fuse_conn *fc)
 	}
 }
 
-static struct fuse_req *__fuse_get_req(struct fuse_conn *fc, unsigned npages,
-				       bool for_background)
+static void fuse_put_request(struct fuse_conn *fc, struct fuse_req *req);
+
+static struct fuse_req *fuse_get_req(struct fuse_conn *fc, bool for_background)
 {
 	struct fuse_req *req;
 	int err;
@@ -201,7 +125,7 @@ static struct fuse_req *__fuse_get_req(struct fuse_conn *fc, unsigned npages,
 	if (fc->conn_error)
 		goto out;
 
-	req = fuse_request_alloc(npages);
+	req = fuse_request_alloc(GFP_KERNEL);
 	err = -ENOMEM;
 	if (!req) {
 		if (for_background)
@@ -229,101 +153,7 @@ static struct fuse_req *__fuse_get_req(struct fuse_conn *fc, unsigned npages,
 	return ERR_PTR(err);
 }
 
-struct fuse_req *fuse_get_req(struct fuse_conn *fc, unsigned npages)
-{
-	return __fuse_get_req(fc, npages, false);
-}
-EXPORT_SYMBOL_GPL(fuse_get_req);
-
-struct fuse_req *fuse_get_req_for_background(struct fuse_conn *fc,
-					     unsigned npages)
-{
-	return __fuse_get_req(fc, npages, true);
-}
-EXPORT_SYMBOL_GPL(fuse_get_req_for_background);
-
-/*
- * 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)
-{
-	struct fuse_req *req = NULL;
-	struct fuse_inode *fi = get_fuse_inode(file_inode(file));
-	struct fuse_file *ff = file->private_data;
-
-	do {
-		wait_event(fc->reserved_req_waitq, ff->reserved_req);
-		spin_lock(&fi->lock);
-		if (ff->reserved_req) {
-			req = ff->reserved_req;
-			ff->reserved_req = NULL;
-			req->stolen_file = get_file(file);
-		}
-		spin_unlock(&fi->lock);
-	} while (!req);
-
-	return req;
-}
-
-/*
- * Put stolen request back into fuse_file->reserved_req
- */
-static void put_reserved_req(struct fuse_conn *fc, struct fuse_req *req)
-{
-	struct file *file = req->stolen_file;
-	struct fuse_inode *fi = get_fuse_inode(file_inode(file));
-	struct fuse_file *ff = file->private_data;
-
-	WARN_ON(req->max_pages);
-	spin_lock(&fi->lock);
-	memset(req, 0, sizeof(*req));
-	fuse_request_init(req, NULL, NULL, 0);
-	BUG_ON(ff->reserved_req);
-	ff->reserved_req = req;
-	wake_up_all(&fc->reserved_req_waitq);
-	spin_unlock(&fi->lock);
-	fput(file);
-}
-
-/*
- * Gets a requests for a file operation, always succeeds
- *
- * This is used for sending the FLUSH request, which must get to
- * userspace, due to POSIX locks which may need to be unlocked.
- *
- * 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.
- */
-struct fuse_req *fuse_get_req_nofail_nopages(struct fuse_conn *fc,
-					     struct file *file)
-{
-	struct fuse_req *req;
-
-	atomic_inc(&fc->num_waiting);
-	wait_event(fc->blocked_waitq, fc->initialized);
-	/* Matches smp_wmb() in fuse_set_initialized() */
-	smp_rmb();
-	req = fuse_request_alloc(0);
-	if (!req)
-		req = get_reserved_req(fc, file);
-
-	req->in.h.uid = from_kuid_munged(fc->user_ns, current_fsuid());
-	req->in.h.gid = from_kgid_munged(fc->user_ns, current_fsgid());
-	req->in.h.pid = pid_nr_ns(task_pid(current), fc->pid_ns);
-
-	__set_bit(FR_WAITING, &req->flags);
-	__clear_bit(FR_BACKGROUND, &req->flags);
-	return req;
-}
-
-void fuse_put_request(struct fuse_conn *fc, struct fuse_req *req)
+static void fuse_put_request(struct fuse_conn *fc, struct fuse_req *req)
 {
 	if (refcount_dec_and_test(&req->count)) {
 		if (test_bit(FR_BACKGROUND, &req->flags)) {
@@ -342,15 +172,11 @@ void fuse_put_request(struct fuse_conn *fc, struct fuse_req *req)
 			fuse_drop_waiting(fc);
 		}
 
-		if (req->stolen_file)
-			put_reserved_req(fc, req);
-		else
-			fuse_request_free(req);
+		fuse_request_free(req);
 	}
 }
-EXPORT_SYMBOL_GPL(fuse_put_request);
 
-static unsigned len_args(unsigned numargs, struct fuse_arg *args)
+unsigned int fuse_len_args(unsigned int numargs, struct fuse_arg *args)
 {
 	unsigned nbytes = 0;
 	unsigned i;
@@ -360,25 +186,47 @@ static unsigned len_args(unsigned numargs, struct fuse_arg *args)
 
 	return nbytes;
 }
+EXPORT_SYMBOL_GPL(fuse_len_args);
 
-static u64 fuse_get_unique(struct fuse_iqueue *fiq)
+u64 fuse_get_unique(struct fuse_iqueue *fiq)
 {
 	fiq->reqctr += FUSE_REQ_ID_STEP;
 	return fiq->reqctr;
 }
+EXPORT_SYMBOL_GPL(fuse_get_unique);
 
 static unsigned int fuse_req_hash(u64 unique)
 {
 	return hash_long(unique & ~FUSE_INT_REQ_BIT, FUSE_PQ_HASH_BITS);
 }
 
-static void queue_request(struct fuse_iqueue *fiq, struct fuse_req *req)
+/**
+ * A new request is available, wake fiq->waitq
+ */
+static void fuse_dev_wake_and_unlock(struct fuse_iqueue *fiq)
+__releases(fiq->lock)
+{
+	wake_up(&fiq->waitq);
+	kill_fasync(&fiq->fasync, SIGIO, POLL_IN);
+	spin_unlock(&fiq->lock);
+}
+
+const struct fuse_iqueue_ops fuse_dev_fiq_ops = {
+	.wake_forget_and_unlock		= fuse_dev_wake_and_unlock,
+	.wake_interrupt_and_unlock	= fuse_dev_wake_and_unlock,
+	.wake_pending_and_unlock	= fuse_dev_wake_and_unlock,
+};
+EXPORT_SYMBOL_GPL(fuse_dev_fiq_ops);
+
+static void queue_request_and_unlock(struct fuse_iqueue *fiq,
+				     struct fuse_req *req)
+__releases(fiq->lock)
 {
 	req->in.h.len = sizeof(struct fuse_in_header) +
-		len_args(req->in.numargs, (struct fuse_arg *) req->in.args);
+		fuse_len_args(req->args->in_numargs,
+			      (struct fuse_arg *) req->args->in_args);
 	list_add_tail(&req->list, &fiq->pending);
-	wake_up_locked(&fiq->waitq);
-	kill_fasync(&fiq->fasync, SIGIO, POLL_IN);
+	fiq->ops->wake_pending_and_unlock(fiq);
 }
 
 void fuse_queue_forget(struct fuse_conn *fc, struct fuse_forget_link *forget,
@@ -389,16 +237,15 @@ void fuse_queue_forget(struct fuse_conn *fc, struct fuse_forget_link *forget,
 	forget->forget_one.nodeid = nodeid;
 	forget->forget_one.nlookup = nlookup;
 
-	spin_lock(&fiq->waitq.lock);
+	spin_lock(&fiq->lock);
 	if (fiq->connected) {
 		fiq->forget_list_tail->next = forget;
 		fiq->forget_list_tail = forget;
-		wake_up_locked(&fiq->waitq);
-		kill_fasync(&fiq->fasync, SIGIO, POLL_IN);
+		fiq->ops->wake_forget_and_unlock(fiq);
 	} else {
 		kfree(forget);
+		spin_unlock(&fiq->lock);
 	}
-	spin_unlock(&fiq->waitq.lock);
 }
 
 static void flush_bg_queue(struct fuse_conn *fc)
@@ -412,10 +259,9 @@ static void flush_bg_queue(struct fuse_conn *fc)
 		req = list_first_entry(&fc->bg_queue, struct fuse_req, list);
 		list_del(&req->list);
 		fc->active_background++;
-		spin_lock(&fiq->waitq.lock);
+		spin_lock(&fiq->lock);
 		req->in.h.unique = fuse_get_unique(fiq);
-		queue_request(fiq, req);
-		spin_unlock(&fiq->waitq.lock);
+		queue_request_and_unlock(fiq, req);
 	}
 }
 
@@ -427,9 +273,10 @@ static void flush_bg_queue(struct fuse_conn *fc)
  * the 'end' callback is called if given, else the reference to the
  * request is released
  */
-static void request_end(struct fuse_conn *fc, struct fuse_req *req)
+void fuse_request_end(struct fuse_conn *fc, struct fuse_req *req)
 {
 	struct fuse_iqueue *fiq = &fc->iq;
+	bool async = req->args->end;
 
 	if (test_and_set_bit(FR_FINISHED, &req->flags))
 		goto put_request;
@@ -439,9 +286,9 @@ static void request_end(struct fuse_conn *fc, struct fuse_req *req)
 	 * smp_mb() from queue_interrupt().
 	 */
 	if (!list_empty(&req->intr_entry)) {
-		spin_lock(&fiq->waitq.lock);
+		spin_lock(&fiq->lock);
 		list_del_init(&req->intr_entry);
-		spin_unlock(&fiq->waitq.lock);
+		spin_unlock(&fiq->lock);
 	}
 	WARN_ON(test_bit(FR_PENDING, &req->flags));
 	WARN_ON(test_bit(FR_SENT, &req->flags));
@@ -475,18 +322,19 @@ static void request_end(struct fuse_conn *fc, struct fuse_req *req)
 		wake_up(&req->waitq);
 	}
 
-	if (req->end)
-		req->end(fc, req);
+	if (async)
+		req->args->end(fc, req->args, req->out.h.error);
 put_request:
 	fuse_put_request(fc, req);
 }
+EXPORT_SYMBOL_GPL(fuse_request_end);
 
 static int queue_interrupt(struct fuse_iqueue *fiq, struct fuse_req *req)
 {
-	spin_lock(&fiq->waitq.lock);
+	spin_lock(&fiq->lock);
 	/* Check for we've sent request to interrupt this req */
 	if (unlikely(!test_bit(FR_INTERRUPTED, &req->flags))) {
-		spin_unlock(&fiq->waitq.lock);
+		spin_unlock(&fiq->lock);
 		return -EINVAL;
 	}
 
@@ -499,13 +347,13 @@ static int queue_interrupt(struct fuse_iqueue *fiq, struct fuse_req *req)
 		smp_mb();
 		if (test_bit(FR_FINISHED, &req->flags)) {
 			list_del_init(&req->intr_entry);
-			spin_unlock(&fiq->waitq.lock);
+			spin_unlock(&fiq->lock);
 			return 0;
 		}
-		wake_up_locked(&fiq->waitq);
-		kill_fasync(&fiq->fasync, SIGIO, POLL_IN);
+		fiq->ops->wake_interrupt_and_unlock(fiq);
+	} else {
+		spin_unlock(&fiq->lock);
 	}
-	spin_unlock(&fiq->waitq.lock);
 	return 0;
 }
 
@@ -535,16 +383,16 @@ static void request_wait_answer(struct fuse_conn *fc, struct fuse_req *req)
 		if (!err)
 			return;
 
-		spin_lock(&fiq->waitq.lock);
+		spin_lock(&fiq->lock);
 		/* Request is not yet in userspace, bail out */
 		if (test_bit(FR_PENDING, &req->flags)) {
 			list_del(&req->list);
-			spin_unlock(&fiq->waitq.lock);
+			spin_unlock(&fiq->lock);
 			__fuse_put_request(req);
 			req->out.h.error = -EINTR;
 			return;
 		}
-		spin_unlock(&fiq->waitq.lock);
+		spin_unlock(&fiq->lock);
 	}
 
 	/*
@@ -559,101 +407,110 @@ static void __fuse_request_send(struct fuse_conn *fc, struct fuse_req *req)
 	struct fuse_iqueue *fiq = &fc->iq;
 
 	BUG_ON(test_bit(FR_BACKGROUND, &req->flags));
-	spin_lock(&fiq->waitq.lock);
+	spin_lock(&fiq->lock);
 	if (!fiq->connected) {
-		spin_unlock(&fiq->waitq.lock);
+		spin_unlock(&fiq->lock);
 		req->out.h.error = -ENOTCONN;
 	} else {
 		req->in.h.unique = fuse_get_unique(fiq);
-		queue_request(fiq, req);
 		/* acquire extra reference, since request is still needed
-		   after request_end() */
+		   after fuse_request_end() */
 		__fuse_get_request(req);
-		spin_unlock(&fiq->waitq.lock);
+		queue_request_and_unlock(fiq, req);
 
 		request_wait_answer(fc, req);
-		/* Pairs with smp_wmb() in request_end() */
+		/* Pairs with smp_wmb() in fuse_request_end() */
 		smp_rmb();
 	}
 }
 
-void fuse_request_send(struct fuse_conn *fc, struct fuse_req *req)
-{
-	__set_bit(FR_ISREPLY, &req->flags);
-	if (!test_bit(FR_WAITING, &req->flags)) {
-		__set_bit(FR_WAITING, &req->flags);
-		atomic_inc(&fc->num_waiting);
-	}
-	__fuse_request_send(fc, req);
-}
-EXPORT_SYMBOL_GPL(fuse_request_send);
-
 static void fuse_adjust_compat(struct fuse_conn *fc, struct fuse_args *args)
 {
-	if (fc->minor < 4 && args->in.h.opcode == FUSE_STATFS)
-		args->out.args[0].size = FUSE_COMPAT_STATFS_SIZE;
+	if (fc->minor < 4 && args->opcode == FUSE_STATFS)
+		args->out_args[0].size = FUSE_COMPAT_STATFS_SIZE;
 
 	if (fc->minor < 9) {
-		switch (args->in.h.opcode) {
+		switch (args->opcode) {
 		case FUSE_LOOKUP:
 		case FUSE_CREATE:
 		case FUSE_MKNOD:
 		case FUSE_MKDIR:
 		case FUSE_SYMLINK:
 		case FUSE_LINK:
-			args->out.args[0].size = FUSE_COMPAT_ENTRY_OUT_SIZE;
+			args->out_args[0].size = FUSE_COMPAT_ENTRY_OUT_SIZE;
 			break;
 		case FUSE_GETATTR:
 		case FUSE_SETATTR:
-			args->out.args[0].size = FUSE_COMPAT_ATTR_OUT_SIZE;
+			args->out_args[0].size = FUSE_COMPAT_ATTR_OUT_SIZE;
 			break;
 		}
 	}
 	if (fc->minor < 12) {
-		switch (args->in.h.opcode) {
+		switch (args->opcode) {
 		case FUSE_CREATE:
-			args->in.args[0].size = sizeof(struct fuse_open_in);
+			args->in_args[0].size = sizeof(struct fuse_open_in);
 			break;
 		case FUSE_MKNOD:
-			args->in.args[0].size = FUSE_COMPAT_MKNOD_IN_SIZE;
+			args->in_args[0].size = FUSE_COMPAT_MKNOD_IN_SIZE;
 			break;
 		}
 	}
 }
 
+static void fuse_force_creds(struct fuse_conn *fc, struct fuse_req *req)
+{
+	req->in.h.uid = from_kuid_munged(fc->user_ns, current_fsuid());
+	req->in.h.gid = from_kgid_munged(fc->user_ns, current_fsgid());
+	req->in.h.pid = pid_nr_ns(task_pid(current), fc->pid_ns);
+}
+
+static void fuse_args_to_req(struct fuse_req *req, struct fuse_args *args)
+{
+	req->in.h.opcode = args->opcode;
+	req->in.h.nodeid = args->nodeid;
+	req->args = args;
+}
+
 ssize_t fuse_simple_request(struct fuse_conn *fc, struct fuse_args *args)
 {
 	struct fuse_req *req;
 	ssize_t ret;
 
-	req = fuse_get_req(fc, 0);
-	if (IS_ERR(req))
-		return PTR_ERR(req);
+	if (args->force) {
+		atomic_inc(&fc->num_waiting);
+		req = fuse_request_alloc(GFP_KERNEL | __GFP_NOFAIL);
+
+		if (!args->nocreds)
+			fuse_force_creds(fc, req);
+
+		__set_bit(FR_WAITING, &req->flags);
+		__set_bit(FR_FORCE, &req->flags);
+	} else {
+		WARN_ON(args->nocreds);
+		req = fuse_get_req(fc, false);
+		if (IS_ERR(req))
+			return PTR_ERR(req);
+	}
 
 	/* Needs to be done after fuse_get_req() so that fc->minor is valid */
 	fuse_adjust_compat(fc, args);
+	fuse_args_to_req(req, args);
 
-	req->in.h.opcode = args->in.h.opcode;
-	req->in.h.nodeid = args->in.h.nodeid;
-	req->in.numargs = args->in.numargs;
-	memcpy(req->in.args, args->in.args,
-	       args->in.numargs * sizeof(struct fuse_in_arg));
-	req->out.argvar = args->out.argvar;
-	req->out.numargs = args->out.numargs;
-	memcpy(req->out.args, args->out.args,
-	       args->out.numargs * sizeof(struct fuse_arg));
-	fuse_request_send(fc, req);
+	if (!args->noreply)
+		__set_bit(FR_ISREPLY, &req->flags);
+	__fuse_request_send(fc, req);
 	ret = req->out.h.error;
-	if (!ret && args->out.argvar) {
-		BUG_ON(args->out.numargs != 1);
-		ret = req->out.args[0].size;
+	if (!ret && args->out_argvar) {
+		BUG_ON(args->out_numargs == 0);
+		ret = args->out_args[args->out_numargs - 1].size;
 	}
 	fuse_put_request(fc, req);
 
 	return ret;
 }
 
-bool fuse_request_queue_background(struct fuse_conn *fc, struct fuse_req *req)
+static bool fuse_request_queue_background(struct fuse_conn *fc,
+					  struct fuse_req *req)
 {
 	bool queued = false;
 
@@ -681,56 +538,63 @@ bool fuse_request_queue_background(struct fuse_conn *fc, struct fuse_req *req)
 	return queued;
 }
 
-void fuse_request_send_background(struct fuse_conn *fc, struct fuse_req *req)
+int fuse_simple_background(struct fuse_conn *fc, struct fuse_args *args,
+			    gfp_t gfp_flags)
 {
-	WARN_ON(!req->end);
+	struct fuse_req *req;
+
+	if (args->force) {
+		WARN_ON(!args->nocreds);
+		req = fuse_request_alloc(gfp_flags);
+		if (!req)
+			return -ENOMEM;
+		__set_bit(FR_BACKGROUND, &req->flags);
+	} else {
+		WARN_ON(args->nocreds);
+		req = fuse_get_req(fc, true);
+		if (IS_ERR(req))
+			return PTR_ERR(req);
+	}
+
+	fuse_args_to_req(req, args);
+
 	if (!fuse_request_queue_background(fc, req)) {
-		req->out.h.error = -ENOTCONN;
-		req->end(fc, req);
 		fuse_put_request(fc, req);
+		return -ENOTCONN;
 	}
+
+	return 0;
 }
-EXPORT_SYMBOL_GPL(fuse_request_send_background);
+EXPORT_SYMBOL_GPL(fuse_simple_background);
 
-static int fuse_request_send_notify_reply(struct fuse_conn *fc,
-					  struct fuse_req *req, u64 unique)
+static int fuse_simple_notify_reply(struct fuse_conn *fc,
+				    struct fuse_args *args, u64 unique)
 {
-	int err = -ENODEV;
+	struct fuse_req *req;
 	struct fuse_iqueue *fiq = &fc->iq;
+	int err = 0;
+
+	req = fuse_get_req(fc, false);
+	if (IS_ERR(req))
+		return PTR_ERR(req);
 
 	__clear_bit(FR_ISREPLY, &req->flags);
 	req->in.h.unique = unique;
-	spin_lock(&fiq->waitq.lock);
+
+	fuse_args_to_req(req, args);
+
+	spin_lock(&fiq->lock);
 	if (fiq->connected) {
-		queue_request(fiq, req);
-		err = 0;
+		queue_request_and_unlock(fiq, req);
+	} else {
+		err = -ENODEV;
+		spin_unlock(&fiq->lock);
+		fuse_put_request(fc, req);
 	}
-	spin_unlock(&fiq->waitq.lock);
 
 	return err;
 }
 
-void fuse_force_forget(struct file *file, u64 nodeid)
-{
-	struct inode *inode = file_inode(file);
-	struct fuse_conn *fc = get_fuse_conn(inode);
-	struct fuse_req *req;
-	struct fuse_forget_in inarg;
-
-	memset(&inarg, 0, sizeof(inarg));
-	inarg.nlookup = 1;
-	req = fuse_get_req_nofail_nopages(fc, file);
-	req->in.h.opcode = FUSE_FORGET;
-	req->in.h.nodeid = nodeid;
-	req->in.numargs = 1;
-	req->in.args[0].size = sizeof(inarg);
-	req->in.args[0].value = &inarg;
-	__clear_bit(FR_ISREPLY, &req->flags);
-	__fuse_request_send(fc, req);
-	/* ignore errors */
-	fuse_put_request(fc, req);
-}
-
 /*
  * 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
@@ -1084,14 +948,15 @@ static int fuse_copy_pages(struct fuse_copy_state *cs, unsigned nbytes,
 {
 	unsigned i;
 	struct fuse_req *req = cs->req;
+	struct fuse_args_pages *ap = container_of(req->args, typeof(*ap), args);
+
 
-	for (i = 0; i < req->num_pages && (nbytes || zeroing); i++) {
+	for (i = 0; i < ap->num_pages && (nbytes || zeroing); i++) {
 		int err;
-		unsigned offset = req->page_descs[i].offset;
-		unsigned count = min(nbytes, req->page_descs[i].length);
+		unsigned int offset = ap->descs[i].offset;
+		unsigned int count = min(nbytes, ap->descs[i].length);
 
-		err = fuse_copy_page(cs, &req->pages[i], offset, count,
-				     zeroing);
+		err = fuse_copy_page(cs, &ap->pages[i], offset, count, zeroing);
 		if (err)
 			return err;
 
@@ -1149,12 +1014,12 @@ static int request_pending(struct fuse_iqueue *fiq)
  * Unlike other requests this is assembled on demand, without a need
  * to allocate a separate fuse_req structure.
  *
- * Called with fiq->waitq.lock held, releases it
+ * Called with fiq->lock held, releases it
  */
 static int fuse_read_interrupt(struct fuse_iqueue *fiq,
 			       struct fuse_copy_state *cs,
 			       size_t nbytes, struct fuse_req *req)
-__releases(fiq->waitq.lock)
+__releases(fiq->lock)
 {
 	struct fuse_in_header ih;
 	struct fuse_interrupt_in arg;
@@ -1169,7 +1034,7 @@ __releases(fiq->waitq.lock)
 	ih.unique = (req->in.h.unique | FUSE_INT_REQ_BIT);
 	arg.unique = req->in.h.unique;
 
-	spin_unlock(&fiq->waitq.lock);
+	spin_unlock(&fiq->lock);
 	if (nbytes < reqsize)
 		return -EINVAL;
 
@@ -1181,9 +1046,9 @@ __releases(fiq->waitq.lock)
 	return err ? err : reqsize;
 }
 
-static struct fuse_forget_link *dequeue_forget(struct fuse_iqueue *fiq,
-					       unsigned max,
-					       unsigned *countp)
+struct fuse_forget_link *fuse_dequeue_forget(struct fuse_iqueue *fiq,
+					     unsigned int max,
+					     unsigned int *countp)
 {
 	struct fuse_forget_link *head = fiq->forget_list_head.next;
 	struct fuse_forget_link **newhead = &head;
@@ -1202,14 +1067,15 @@ static struct fuse_forget_link *dequeue_forget(struct fuse_iqueue *fiq,
 
 	return head;
 }
+EXPORT_SYMBOL(fuse_dequeue_forget);
 
 static int fuse_read_single_forget(struct fuse_iqueue *fiq,
 				   struct fuse_copy_state *cs,
 				   size_t nbytes)
-__releases(fiq->waitq.lock)
+__releases(fiq->lock)
 {
 	int err;
-	struct fuse_forget_link *forget = dequeue_forget(fiq, 1, NULL);
+	struct fuse_forget_link *forget = fuse_dequeue_forget(fiq, 1, NULL);
 	struct fuse_forget_in arg = {
 		.nlookup = forget->forget_one.nlookup,
 	};
@@ -1220,7 +1086,7 @@ __releases(fiq->waitq.lock)
 		.len = sizeof(ih) + sizeof(arg),
 	};
 
-	spin_unlock(&fiq->waitq.lock);
+	spin_unlock(&fiq->lock);
 	kfree(forget);
 	if (nbytes < ih.len)
 		return -EINVAL;
@@ -1238,7 +1104,7 @@ __releases(fiq->waitq.lock)
 
 static int fuse_read_batch_forget(struct fuse_iqueue *fiq,
 				   struct fuse_copy_state *cs, size_t nbytes)
-__releases(fiq->waitq.lock)
+__releases(fiq->lock)
 {
 	int err;
 	unsigned max_forgets;
@@ -1252,13 +1118,13 @@ __releases(fiq->waitq.lock)
 	};
 
 	if (nbytes < ih.len) {
-		spin_unlock(&fiq->waitq.lock);
+		spin_unlock(&fiq->lock);
 		return -EINVAL;
 	}
 
 	max_forgets = (nbytes - ih.len) / sizeof(struct fuse_forget_one);
-	head = dequeue_forget(fiq, max_forgets, &count);
-	spin_unlock(&fiq->waitq.lock);
+	head = fuse_dequeue_forget(fiq, max_forgets, &count);
+	spin_unlock(&fiq->lock);
 
 	arg.count = count;
 	ih.len += count * sizeof(struct fuse_forget_one);
@@ -1288,7 +1154,7 @@ __releases(fiq->waitq.lock)
 static int fuse_read_forget(struct fuse_conn *fc, struct fuse_iqueue *fiq,
 			    struct fuse_copy_state *cs,
 			    size_t nbytes)
-__releases(fiq->waitq.lock)
+__releases(fiq->lock)
 {
 	if (fc->minor < 16 || fiq->forget_list_head.next->next == NULL)
 		return fuse_read_single_forget(fiq, cs, nbytes);
@@ -1302,7 +1168,7 @@ __releases(fiq->waitq.lock)
  * the pending list and copies request data to userspace buffer.  If
  * 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
+ * fuse_request_end().  Otherwise add it to the processing list, and set
  * the 'sent' flag.
  */
 static ssize_t fuse_dev_do_read(struct fuse_dev *fud, struct file *file,
@@ -1313,21 +1179,42 @@ static ssize_t fuse_dev_do_read(struct fuse_dev *fud, struct file *file,
 	struct fuse_iqueue *fiq = &fc->iq;
 	struct fuse_pqueue *fpq = &fud->pq;
 	struct fuse_req *req;
-	struct fuse_in *in;
+	struct fuse_args *args;
 	unsigned reqsize;
 	unsigned int hash;
 
+	/*
+	 * Require sane minimum read buffer - that has capacity for fixed part
+	 * of any request header + negotiated max_write room for data.
+	 *
+	 * Historically libfuse reserves 4K for fixed header room, but e.g.
+	 * GlusterFS reserves only 80 bytes
+	 *
+	 *	= `sizeof(fuse_in_header) + sizeof(fuse_write_in)`
+	 *
+	 * which is the absolute minimum any sane filesystem should be using
+	 * for header room.
+	 */
+	if (nbytes < max_t(size_t, FUSE_MIN_READ_BUFFER,
+			   sizeof(struct fuse_in_header) +
+			   sizeof(struct fuse_write_in) +
+			   fc->max_write))
+		return -EINVAL;
+
  restart:
-	spin_lock(&fiq->waitq.lock);
-	err = -EAGAIN;
-	if ((file->f_flags & O_NONBLOCK) && fiq->connected &&
-	    !request_pending(fiq))
-		goto err_unlock;
+	for (;;) {
+		spin_lock(&fiq->lock);
+		if (!fiq->connected || request_pending(fiq))
+			break;
+		spin_unlock(&fiq->lock);
 
-	err = wait_event_interruptible_exclusive_locked(fiq->waitq,
+		if (file->f_flags & O_NONBLOCK)
+			return -EAGAIN;
+		err = wait_event_interruptible_exclusive(fiq->waitq,
 				!fiq->connected || request_pending(fiq));
-	if (err)
-		goto err_unlock;
+		if (err)
+			return err;
+	}
 
 	if (!fiq->connected) {
 		err = fc->aborted ? -ECONNABORTED : -ENODEV;
@@ -1351,28 +1238,28 @@ static ssize_t fuse_dev_do_read(struct fuse_dev *fud, struct file *file,
 	req = list_entry(fiq->pending.next, struct fuse_req, list);
 	clear_bit(FR_PENDING, &req->flags);
 	list_del_init(&req->list);
-	spin_unlock(&fiq->waitq.lock);
+	spin_unlock(&fiq->lock);
 
-	in = &req->in;
-	reqsize = in->h.len;
+	args = req->args;
+	reqsize = req->in.h.len;
 
 	/* If request is too large, reply with an error and restart the read */
 	if (nbytes < reqsize) {
 		req->out.h.error = -EIO;
 		/* SETXATTR is special, since it may contain too large data */
-		if (in->h.opcode == FUSE_SETXATTR)
+		if (args->opcode == FUSE_SETXATTR)
 			req->out.h.error = -E2BIG;
-		request_end(fc, req);
+		fuse_request_end(fc, req);
 		goto restart;
 	}
 	spin_lock(&fpq->lock);
 	list_add(&req->list, &fpq->io);
 	spin_unlock(&fpq->lock);
 	cs->req = req;
-	err = fuse_copy_one(cs, &in->h, sizeof(in->h));
+	err = fuse_copy_one(cs, &req->in.h, sizeof(req->in.h));
 	if (!err)
-		err = fuse_copy_args(cs, in->numargs, in->argpages,
-				     (struct fuse_arg *) in->args, 0);
+		err = fuse_copy_args(cs, args->in_numargs, args->in_pages,
+				     (struct fuse_arg *) args->in_args, 0);
 	fuse_copy_finish(cs);
 	spin_lock(&fpq->lock);
 	clear_bit(FR_LOCKED, &req->flags);
@@ -1405,11 +1292,11 @@ static ssize_t fuse_dev_do_read(struct fuse_dev *fud, struct file *file,
 	if (!test_bit(FR_PRIVATE, &req->flags))
 		list_del_init(&req->list);
 	spin_unlock(&fpq->lock);
-	request_end(fc, req);
+	fuse_request_end(fc, req);
 	return err;
 
  err_unlock:
-	spin_unlock(&fiq->waitq.lock);
+	spin_unlock(&fiq->lock);
 	return err;
 }
 
@@ -1728,9 +1615,19 @@ static int fuse_notify_store(struct fuse_conn *fc, unsigned int size,
 	return err;
 }
 
-static void fuse_retrieve_end(struct fuse_conn *fc, struct fuse_req *req)
+struct fuse_retrieve_args {
+	struct fuse_args_pages ap;
+	struct fuse_notify_retrieve_in inarg;
+};
+
+static void fuse_retrieve_end(struct fuse_conn *fc, struct fuse_args *args,
+			      int error)
 {
-	release_pages(req->pages, req->num_pages);
+	struct fuse_retrieve_args *ra =
+		container_of(args, typeof(*ra), ap.args);
+
+	release_pages(ra->ap.pages, ra->ap.num_pages);
+	kfree(ra);
 }
 
 static int fuse_retrieve(struct fuse_conn *fc, struct inode *inode,
@@ -1738,13 +1635,16 @@ static int fuse_retrieve(struct fuse_conn *fc, struct inode *inode,
 {
 	int err;
 	struct address_space *mapping = inode->i_mapping;
-	struct fuse_req *req;
 	pgoff_t index;
 	loff_t file_size;
 	unsigned int num;
 	unsigned int offset;
 	size_t total_len = 0;
 	unsigned int num_pages;
+	struct fuse_retrieve_args *ra;
+	size_t args_size = sizeof(*ra);
+	struct fuse_args_pages *ap;
+	struct fuse_args *args;
 
 	offset = outarg->offset & ~PAGE_MASK;
 	file_size = i_size_read(inode);
@@ -1758,19 +1658,26 @@ static int fuse_retrieve(struct fuse_conn *fc, struct inode *inode,
 	num_pages = (num + offset + PAGE_SIZE - 1) >> PAGE_SHIFT;
 	num_pages = min(num_pages, fc->max_pages);
 
-	req = fuse_get_req(fc, num_pages);
-	if (IS_ERR(req))
-		return PTR_ERR(req);
+	args_size += num_pages * (sizeof(ap->pages[0]) + sizeof(ap->descs[0]));
 
-	req->in.h.opcode = FUSE_NOTIFY_REPLY;
-	req->in.h.nodeid = outarg->nodeid;
-	req->in.numargs = 2;
-	req->in.argpages = 1;
-	req->end = fuse_retrieve_end;
+	ra = kzalloc(args_size, GFP_KERNEL);
+	if (!ra)
+		return -ENOMEM;
+
+	ap = &ra->ap;
+	ap->pages = (void *) (ra + 1);
+	ap->descs = (void *) (ap->pages + num_pages);
+
+	args = &ap->args;
+	args->nodeid = outarg->nodeid;
+	args->opcode = FUSE_NOTIFY_REPLY;
+	args->in_numargs = 2;
+	args->in_pages = true;
+	args->end = fuse_retrieve_end;
 
 	index = outarg->offset >> PAGE_SHIFT;
 
-	while (num && req->num_pages < num_pages) {
+	while (num && ap->num_pages < num_pages) {
 		struct page *page;
 		unsigned int this_num;
 
@@ -1779,27 +1686,25 @@ static int fuse_retrieve(struct fuse_conn *fc, struct inode *inode,
 			break;
 
 		this_num = min_t(unsigned, num, PAGE_SIZE - offset);
-		req->pages[req->num_pages] = page;
-		req->page_descs[req->num_pages].offset = offset;
-		req->page_descs[req->num_pages].length = this_num;
-		req->num_pages++;
+		ap->pages[ap->num_pages] = page;
+		ap->descs[ap->num_pages].offset = offset;
+		ap->descs[ap->num_pages].length = this_num;
+		ap->num_pages++;
 
 		offset = 0;
 		num -= this_num;
 		total_len += this_num;
 		index++;
 	}
-	req->misc.retrieve_in.offset = outarg->offset;
-	req->misc.retrieve_in.size = total_len;
-	req->in.args[0].size = sizeof(req->misc.retrieve_in);
-	req->in.args[0].value = &req->misc.retrieve_in;
-	req->in.args[1].size = total_len;
+	ra->inarg.offset = outarg->offset;
+	ra->inarg.size = total_len;
+	args->in_args[0].size = sizeof(ra->inarg);
+	args->in_args[0].value = &ra->inarg;
+	args->in_args[1].size = total_len;
 
-	err = fuse_request_send_notify_reply(fc, req, outarg->notify_unique);
-	if (err) {
-		fuse_retrieve_end(fc, req);
-		fuse_put_request(fc, req);
-	}
+	err = fuse_simple_notify_reply(fc, args, outarg->notify_unique);
+	if (err)
+		fuse_retrieve_end(fc, args, err);
 
 	return err;
 }
@@ -1885,27 +1790,25 @@ static struct fuse_req *request_find(struct fuse_pqueue *fpq, u64 unique)
 	return NULL;
 }
 
-static int copy_out_args(struct fuse_copy_state *cs, struct fuse_out *out,
+static int copy_out_args(struct fuse_copy_state *cs, struct fuse_args *args,
 			 unsigned nbytes)
 {
 	unsigned reqsize = sizeof(struct fuse_out_header);
 
-	if (out->h.error)
-		return nbytes != reqsize ? -EINVAL : 0;
-
-	reqsize += len_args(out->numargs, out->args);
+	reqsize += fuse_len_args(args->out_numargs, args->out_args);
 
-	if (reqsize < nbytes || (reqsize > nbytes && !out->argvar))
+	if (reqsize < nbytes || (reqsize > nbytes && !args->out_argvar))
 		return -EINVAL;
 	else if (reqsize > nbytes) {
-		struct fuse_arg *lastarg = &out->args[out->numargs-1];
+		struct fuse_arg *lastarg = &args->out_args[args->out_numargs-1];
 		unsigned diffsize = reqsize - nbytes;
+
 		if (diffsize > lastarg->size)
 			return -EINVAL;
 		lastarg->size -= diffsize;
 	}
-	return fuse_copy_args(cs, out->numargs, out->argpages, out->args,
-			      out->page_zeroing);
+	return fuse_copy_args(cs, args->out_numargs, args->out_pages,
+			      args->out_args, args->page_zeroing);
 }
 
 /*
@@ -1913,7 +1816,7 @@ static int copy_out_args(struct fuse_copy_state *cs, struct fuse_out *out,
  * the write buffer.  The request is then searched on the processing
  * list by the unique ID found in the header.  If found, then remove
  * it from the list and copy the rest of the buffer to the request.
- * The request is finished by calling request_end()
+ * The request is finished by calling fuse_request_end().
  */
 static ssize_t fuse_dev_do_write(struct fuse_dev *fud,
 				 struct fuse_copy_state *cs, size_t nbytes)
@@ -1984,10 +1887,13 @@ static ssize_t fuse_dev_do_write(struct fuse_dev *fud,
 	set_bit(FR_LOCKED, &req->flags);
 	spin_unlock(&fpq->lock);
 	cs->req = req;
-	if (!req->out.page_replace)
+	if (!req->args->page_replace)
 		cs->move_pages = 0;
 
-	err = copy_out_args(cs, &req->out, nbytes);
+	if (oh.error)
+		err = nbytes != sizeof(oh) ? -EINVAL : 0;
+	else
+		err = copy_out_args(cs, req->args, nbytes);
 	fuse_copy_finish(cs);
 
 	spin_lock(&fpq->lock);
@@ -2000,7 +1906,7 @@ static ssize_t fuse_dev_do_write(struct fuse_dev *fud,
 		list_del_init(&req->list);
 	spin_unlock(&fpq->lock);
 
-	request_end(fc, req);
+	fuse_request_end(fc, req);
 out:
 	return err ? err : nbytes;
 
@@ -2121,12 +2027,12 @@ static __poll_t fuse_dev_poll(struct file *file, poll_table *wait)
 	fiq = &fud->fc->iq;
 	poll_wait(file, &fiq->waitq, wait);
 
-	spin_lock(&fiq->waitq.lock);
+	spin_lock(&fiq->lock);
 	if (!fiq->connected)
 		mask = EPOLLERR;
 	else if (request_pending(fiq))
 		mask |= EPOLLIN | EPOLLRDNORM;
-	spin_unlock(&fiq->waitq.lock);
+	spin_unlock(&fiq->lock);
 
 	return mask;
 }
@@ -2140,7 +2046,7 @@ static void end_requests(struct fuse_conn *fc, struct list_head *head)
 		req->out.h.error = -ECONNABORTED;
 		clear_bit(FR_SENT, &req->flags);
 		list_del_init(&req->list);
-		request_end(fc, req);
+		fuse_request_end(fc, req);
 	}
 }
 
@@ -2221,15 +2127,15 @@ void fuse_abort_conn(struct fuse_conn *fc)
 		flush_bg_queue(fc);
 		spin_unlock(&fc->bg_lock);
 
-		spin_lock(&fiq->waitq.lock);
+		spin_lock(&fiq->lock);
 		fiq->connected = 0;
 		list_for_each_entry(req, &fiq->pending, list)
 			clear_bit(FR_PENDING, &req->flags);
 		list_splice_tail_init(&fiq->pending, &to_end);
 		while (forget_pending(fiq))
-			kfree(dequeue_forget(fiq, 1, NULL));
-		wake_up_all_locked(&fiq->waitq);
-		spin_unlock(&fiq->waitq.lock);
+			kfree(fuse_dequeue_forget(fiq, 1, NULL));
+		wake_up_all(&fiq->waitq);
+		spin_unlock(&fiq->lock);
 		kill_fasync(&fiq->fasync, SIGIO, POLL_IN);
 		end_polls(fc);
 		wake_up_all(&fc->blocked_waitq);
@@ -2296,7 +2202,7 @@ static int fuse_device_clone(struct fuse_conn *fc, struct file *new)
 	if (new->private_data)
 		return -EINVAL;
 
-	fud = fuse_dev_alloc(fc);
+	fud = fuse_dev_alloc_install(fc);
 	if (!fud)
 		return -ENOMEM;
 

fs/fuse/dir.c

@@ -24,20 +24,54 @@ static void fuse_advise_use_readdirplus(struct inode *dir)
 	set_bit(FUSE_I_ADVISE_RDPLUS, &fi->state);
 }
 
+#if BITS_PER_LONG >= 64
+static inline void __fuse_dentry_settime(struct dentry *entry, u64 time)
+{
+	entry->d_fsdata = (void *) time;
+}
+
+static inline u64 fuse_dentry_time(const struct dentry *entry)
+{
+	return (u64)entry->d_fsdata;
+}
+
+#else
 union fuse_dentry {
 	u64 time;
 	struct rcu_head rcu;
 };
 
-static inline void fuse_dentry_settime(struct dentry *entry, u64 time)
+static inline void __fuse_dentry_settime(struct dentry *dentry, u64 time)
 {
-	((union fuse_dentry *) entry->d_fsdata)->time = time;
+	((union fuse_dentry *) dentry->d_fsdata)->time = time;
 }
 
-static inline u64 fuse_dentry_time(struct dentry *entry)
+static inline u64 fuse_dentry_time(const struct dentry *entry)
 {
 	return ((union fuse_dentry *) entry->d_fsdata)->time;
 }
+#endif
+
+static void fuse_dentry_settime(struct dentry *dentry, u64 time)
+{
+	struct fuse_conn *fc = get_fuse_conn_super(dentry->d_sb);
+	bool delete = !time && fc->delete_stale;
+	/*
+	 * Mess with DCACHE_OP_DELETE because dput() will be faster without it.
+	 * Don't care about races, either way it's just an optimization
+	 */
+	if ((!delete && (dentry->d_flags & DCACHE_OP_DELETE)) ||
+	    (delete && !(dentry->d_flags & DCACHE_OP_DELETE))) {
+		spin_lock(&dentry->d_lock);
+		if (!delete)
+			dentry->d_flags &= ~DCACHE_OP_DELETE;
+		else
+			dentry->d_flags |= DCACHE_OP_DELETE;
+		spin_unlock(&dentry->d_lock);
+	}
+
+	__fuse_dentry_settime(dentry, time);
+}
 
 /*
  * FUSE caches dentries and attributes with separate timeout.  The
@@ -139,14 +173,14 @@ static void fuse_lookup_init(struct fuse_conn *fc, struct fuse_args *args,
 			     struct fuse_entry_out *outarg)
 {
 	memset(outarg, 0, sizeof(struct fuse_entry_out));
-	args->in.h.opcode = FUSE_LOOKUP;
-	args->in.h.nodeid = nodeid;
-	args->in.numargs = 1;
-	args->in.args[0].size = name->len + 1;
-	args->in.args[0].value = name->name;
-	args->out.numargs = 1;
-	args->out.args[0].size = sizeof(struct fuse_entry_out);
-	args->out.args[0].value = outarg;
+	args->opcode = FUSE_LOOKUP;
+	args->nodeid = nodeid;
+	args->in_numargs = 1;
+	args->in_args[0].size = name->len + 1;
+	args->in_args[0].value = name->name;
+	args->out_numargs = 1;
+	args->out_args[0].size = sizeof(struct fuse_entry_out);
+	args->out_args[0].value = outarg;
 }
 
 /*
@@ -242,9 +276,11 @@ static int fuse_dentry_revalidate(struct dentry *entry, unsigned int flags)
 	goto out;
 }
 
+#if BITS_PER_LONG < 64
 static int fuse_dentry_init(struct dentry *dentry)
 {
-	dentry->d_fsdata = kzalloc(sizeof(union fuse_dentry), GFP_KERNEL);
+	dentry->d_fsdata = kzalloc(sizeof(union fuse_dentry),
+				   GFP_KERNEL_ACCOUNT | __GFP_RECLAIMABLE);
 
 	return dentry->d_fsdata ? 0 : -ENOMEM;
 }
@@ -254,16 +290,27 @@ static void fuse_dentry_release(struct dentry *dentry)
 
 	kfree_rcu(fd, rcu);
 }
+#endif
+
+static int fuse_dentry_delete(const struct dentry *dentry)
+{
+	return time_before64(fuse_dentry_time(dentry), get_jiffies_64());
+}
 
 const struct dentry_operations fuse_dentry_operations = {
 	.d_revalidate	= fuse_dentry_revalidate,
+	.d_delete	= fuse_dentry_delete,
+#if BITS_PER_LONG < 64
 	.d_init		= fuse_dentry_init,
 	.d_release	= fuse_dentry_release,
+#endif
 };
 
 const struct dentry_operations fuse_root_dentry_operations = {
+#if BITS_PER_LONG < 64
 	.d_init		= fuse_dentry_init,
 	.d_release	= fuse_dentry_release,
+#endif
 };
 
 int fuse_valid_type(int m)
@@ -410,18 +457,18 @@ static int fuse_create_open(struct inode *dir, struct dentry *entry,
 	inarg.flags = flags;
 	inarg.mode = mode;
 	inarg.umask = current_umask();
-	args.in.h.opcode = FUSE_CREATE;
-	args.in.h.nodeid = get_node_id(dir);
-	args.in.numargs = 2;
-	args.in.args[0].size = sizeof(inarg);
-	args.in.args[0].value = &inarg;
-	args.in.args[1].size = entry->d_name.len + 1;
-	args.in.args[1].value = entry->d_name.name;
-	args.out.numargs = 2;
-	args.out.args[0].size = sizeof(outentry);
-	args.out.args[0].value = &outentry;
-	args.out.args[1].size = sizeof(outopen);
-	args.out.args[1].value = &outopen;
+	args.opcode = FUSE_CREATE;
+	args.nodeid = get_node_id(dir);
+	args.in_numargs = 2;
+	args.in_args[0].size = sizeof(inarg);
+	args.in_args[0].value = &inarg;
+	args.in_args[1].size = entry->d_name.len + 1;
+	args.in_args[1].value = entry->d_name.name;
+	args.out_numargs = 2;
+	args.out_args[0].size = sizeof(outentry);
+	args.out_args[0].value = &outentry;
+	args.out_args[1].size = sizeof(outopen);
+	args.out_args[1].value = &outopen;
 	err = fuse_simple_request(fc, &args);
 	if (err)
 		goto out_free_ff;
@@ -526,10 +573,10 @@ static int create_new_entry(struct fuse_conn *fc, struct fuse_args *args,
 		return -ENOMEM;
 
 	memset(&outarg, 0, sizeof(outarg));
-	args->in.h.nodeid = get_node_id(dir);
-	args->out.numargs = 1;
-	args->out.args[0].size = sizeof(outarg);
-	args->out.args[0].value = &outarg;
+	args->nodeid = get_node_id(dir);
+	args->out_numargs = 1;
+	args->out_args[0].size = sizeof(outarg);
+	args->out_args[0].value = &outarg;
 	err = fuse_simple_request(fc, args);
 	if (err)
 		goto out_put_forget_req;
@@ -582,12 +629,12 @@ static int fuse_mknod(struct inode *dir, struct dentry *entry, umode_t mode,
 	inarg.mode = mode;
 	inarg.rdev = new_encode_dev(rdev);
 	inarg.umask = current_umask();
-	args.in.h.opcode = FUSE_MKNOD;
-	args.in.numargs = 2;
-	args.in.args[0].size = sizeof(inarg);
-	args.in.args[0].value = &inarg;
-	args.in.args[1].size = entry->d_name.len + 1;
-	args.in.args[1].value = entry->d_name.name;
+	args.opcode = FUSE_MKNOD;
+	args.in_numargs = 2;
+	args.in_args[0].size = sizeof(inarg);
+	args.in_args[0].value = &inarg;
+	args.in_args[1].size = entry->d_name.len + 1;
+	args.in_args[1].value = entry->d_name.name;
 	return create_new_entry(fc, &args, dir, entry, mode);
 }
 
@@ -609,12 +656,12 @@ static int fuse_mkdir(struct inode *dir, struct dentry *entry, umode_t mode)
 	memset(&inarg, 0, sizeof(inarg));
 	inarg.mode = mode;
 	inarg.umask = current_umask();
-	args.in.h.opcode = FUSE_MKDIR;
-	args.in.numargs = 2;
-	args.in.args[0].size = sizeof(inarg);
-	args.in.args[0].value = &inarg;
-	args.in.args[1].size = entry->d_name.len + 1;
-	args.in.args[1].value = entry->d_name.name;
+	args.opcode = FUSE_MKDIR;
+	args.in_numargs = 2;
+	args.in_args[0].size = sizeof(inarg);
+	args.in_args[0].value = &inarg;
+	args.in_args[1].size = entry->d_name.len + 1;
+	args.in_args[1].value = entry->d_name.name;
 	return create_new_entry(fc, &args, dir, entry, S_IFDIR);
 }
 
@@ -625,12 +672,12 @@ static int fuse_symlink(struct inode *dir, struct dentry *entry,
 	unsigned len = strlen(link) + 1;
 	FUSE_ARGS(args);
 
-	args.in.h.opcode = FUSE_SYMLINK;
-	args.in.numargs = 2;
-	args.in.args[0].size = entry->d_name.len + 1;
-	args.in.args[0].value = entry->d_name.name;
-	args.in.args[1].size = len;
-	args.in.args[1].value = link;
+	args.opcode = FUSE_SYMLINK;
+	args.in_numargs = 2;
+	args.in_args[0].size = entry->d_name.len + 1;
+	args.in_args[0].value = entry->d_name.name;
+	args.in_args[1].size = len;
+	args.in_args[1].value = link;
 	return create_new_entry(fc, &args, dir, entry, S_IFLNK);
 }
 
@@ -648,11 +695,11 @@ static int fuse_unlink(struct inode *dir, struct dentry *entry)
 	struct fuse_conn *fc = get_fuse_conn(dir);
 	FUSE_ARGS(args);
 
-	args.in.h.opcode = FUSE_UNLINK;
-	args.in.h.nodeid = get_node_id(dir);
-	args.in.numargs = 1;
-	args.in.args[0].size = entry->d_name.len + 1;
-	args.in.args[0].value = entry->d_name.name;
+	args.opcode = FUSE_UNLINK;
+	args.nodeid = get_node_id(dir);
+	args.in_numargs = 1;
+	args.in_args[0].size = entry->d_name.len + 1;
+	args.in_args[0].value = entry->d_name.name;
 	err = fuse_simple_request(fc, &args);
 	if (!err) {
 		struct inode *inode = d_inode(entry);
@@ -684,11 +731,11 @@ static int fuse_rmdir(struct inode *dir, struct dentry *entry)
 	struct fuse_conn *fc = get_fuse_conn(dir);
 	FUSE_ARGS(args);
 
-	args.in.h.opcode = FUSE_RMDIR;
-	args.in.h.nodeid = get_node_id(dir);
-	args.in.numargs = 1;
-	args.in.args[0].size = entry->d_name.len + 1;
-	args.in.args[0].value = entry->d_name.name;
+	args.opcode = FUSE_RMDIR;
+	args.nodeid = get_node_id(dir);
+	args.in_numargs = 1;
+	args.in_args[0].size = entry->d_name.len + 1;
+	args.in_args[0].value = entry->d_name.name;
 	err = fuse_simple_request(fc, &args);
 	if (!err) {
 		clear_nlink(d_inode(entry));
@@ -711,15 +758,15 @@ static int fuse_rename_common(struct inode *olddir, struct dentry *oldent,
 	memset(&inarg, 0, argsize);
 	inarg.newdir = get_node_id(newdir);
 	inarg.flags = flags;
-	args.in.h.opcode = opcode;
-	args.in.h.nodeid = get_node_id(olddir);
-	args.in.numargs = 3;
-	args.in.args[0].size = argsize;
-	args.in.args[0].value = &inarg;
-	args.in.args[1].size = oldent->d_name.len + 1;
-	args.in.args[1].value = oldent->d_name.name;
-	args.in.args[2].size = newent->d_name.len + 1;
-	args.in.args[2].value = newent->d_name.name;
+	args.opcode = opcode;
+	args.nodeid = get_node_id(olddir);
+	args.in_numargs = 3;
+	args.in_args[0].size = argsize;
+	args.in_args[0].value = &inarg;
+	args.in_args[1].size = oldent->d_name.len + 1;
+	args.in_args[1].value = oldent->d_name.name;
+	args.in_args[2].size = newent->d_name.len + 1;
+	args.in_args[2].value = newent->d_name.name;
 	err = fuse_simple_request(fc, &args);
 	if (!err) {
 		/* ctime changes */
@@ -796,12 +843,12 @@ static int fuse_link(struct dentry *entry, struct inode *newdir,
 
 	memset(&inarg, 0, sizeof(inarg));
 	inarg.oldnodeid = get_node_id(inode);
-	args.in.h.opcode = FUSE_LINK;
-	args.in.numargs = 2;
-	args.in.args[0].size = sizeof(inarg);
-	args.in.args[0].value = &inarg;
-	args.in.args[1].size = newent->d_name.len + 1;
-	args.in.args[1].value = newent->d_name.name;
+	args.opcode = FUSE_LINK;
+	args.in_numargs = 2;
+	args.in_args[0].size = sizeof(inarg);
+	args.in_args[0].value = &inarg;
+	args.in_args[1].size = newent->d_name.len + 1;
+	args.in_args[1].value = newent->d_name.name;
 	err = create_new_entry(fc, &args, newdir, newent, inode->i_mode);
 	/* Contrary to "normal" filesystems it can happen that link
 	   makes two "logical" inodes point to the same "physical"
@@ -884,14 +931,14 @@ static int fuse_do_getattr(struct inode *inode, struct kstat *stat,
 		inarg.getattr_flags |= FUSE_GETATTR_FH;
 		inarg.fh = ff->fh;
 	}
-	args.in.h.opcode = FUSE_GETATTR;
-	args.in.h.nodeid = get_node_id(inode);
-	args.in.numargs = 1;
-	args.in.args[0].size = sizeof(inarg);
-	args.in.args[0].value = &inarg;
-	args.out.numargs = 1;
-	args.out.args[0].size = sizeof(outarg);
-	args.out.args[0].value = &outarg;
+	args.opcode = FUSE_GETATTR;
+	args.nodeid = get_node_id(inode);
+	args.in_numargs = 1;
+	args.in_args[0].size = sizeof(inarg);
+	args.in_args[0].value = &inarg;
+	args.out_numargs = 1;
+	args.out_args[0].size = sizeof(outarg);
+	args.out_args[0].value = &outarg;
 	err = fuse_simple_request(fc, &args);
 	if (!err) {
 		if ((inode->i_mode ^ outarg.attr.mode) & S_IFMT) {
@@ -1056,11 +1103,11 @@ static int fuse_access(struct inode *inode, int mask)
 
 	memset(&inarg, 0, sizeof(inarg));
 	inarg.mask = mask & (MAY_READ | MAY_WRITE | MAY_EXEC);
-	args.in.h.opcode = FUSE_ACCESS;
-	args.in.h.nodeid = get_node_id(inode);
-	args.in.numargs = 1;
-	args.in.args[0].size = sizeof(inarg);
-	args.in.args[0].value = &inarg;
+	args.opcode = FUSE_ACCESS;
+	args.nodeid = get_node_id(inode);
+	args.in_numargs = 1;
+	args.in_args[0].size = sizeof(inarg);
+	args.in_args[0].value = &inarg;
 	err = fuse_simple_request(fc, &args);
 	if (err == -ENOSYS) {
 		fc->no_access = 1;
@@ -1152,38 +1199,36 @@ static int fuse_permission(struct inode *inode, int mask)
 static int fuse_readlink_page(struct inode *inode, struct page *page)
 {
 	struct fuse_conn *fc = get_fuse_conn(inode);
-	struct fuse_req *req;
-	int err;
+	struct fuse_page_desc desc = { .length = PAGE_SIZE - 1 };
+	struct fuse_args_pages ap = {
+		.num_pages = 1,
+		.pages = &page,
+		.descs = &desc,
+	};
+	char *link;
+	ssize_t res;
+
+	ap.args.opcode = FUSE_READLINK;
+	ap.args.nodeid = get_node_id(inode);
+	ap.args.out_pages = true;
+	ap.args.out_argvar = true;
+	ap.args.page_zeroing = true;
+	ap.args.out_numargs = 1;
+	ap.args.out_args[0].size = desc.length;
+	res = fuse_simple_request(fc, &ap.args);
 
-	req = fuse_get_req(fc, 1);
-	if (IS_ERR(req))
-		return PTR_ERR(req);
-
-	req->out.page_zeroing = 1;
-	req->out.argpages = 1;
-	req->num_pages = 1;
-	req->pages[0] = page;
-	req->page_descs[0].length = PAGE_SIZE - 1;
-	req->in.h.opcode = FUSE_READLINK;
-	req->in.h.nodeid = get_node_id(inode);
-	req->out.argvar = 1;
-	req->out.numargs = 1;
-	req->out.args[0].size = PAGE_SIZE - 1;
-	fuse_request_send(fc, req);
-	err = req->out.h.error;
+	fuse_invalidate_atime(inode);
 
-	if (!err) {
-		char *link = page_address(page);
-		size_t len = req->out.args[0].size;
+	if (res < 0)
+		return res;
 
-		BUG_ON(len >= PAGE_SIZE);
-		link[len] = '\0';
-	}
+	if (WARN_ON(res >= PAGE_SIZE))
+		return -EIO;
 
-	fuse_put_request(fc, req);
-	fuse_invalidate_atime(inode);
+	link = page_address(page);
+	link[res] = '\0';
 
-	return err;
+	return 0;
 }
 
 static const char *fuse_get_link(struct dentry *dentry, struct inode *inode,
@@ -1383,14 +1428,14 @@ static void fuse_setattr_fill(struct fuse_conn *fc, struct fuse_args *args,
 			      struct fuse_setattr_in *inarg_p,
 			      struct fuse_attr_out *outarg_p)
 {
-	args->in.h.opcode = FUSE_SETATTR;
-	args->in.h.nodeid = get_node_id(inode);
-	args->in.numargs = 1;
-	args->in.args[0].size = sizeof(*inarg_p);
-	args->in.args[0].value = inarg_p;
-	args->out.numargs = 1;
-	args->out.args[0].size = sizeof(*outarg_p);
-	args->out.args[0].value = outarg_p;
+	args->opcode = FUSE_SETATTR;
+	args->nodeid = get_node_id(inode);
+	args->in_numargs = 1;
+	args->in_args[0].size = sizeof(*inarg_p);
+	args->in_args[0].value = inarg_p;
+	args->out_numargs = 1;
+	args->out_args[0].size = sizeof(*outarg_p);
+	args->out_args[0].value = outarg_p;
 }
 
 /*

fs/fuse/file.c

@@ -19,6 +19,18 @@
 #include <linux/falloc.h>
 #include <linux/uio.h>
 
+static struct page **fuse_pages_alloc(unsigned int npages, gfp_t flags,
+				      struct fuse_page_desc **desc)
+{
+	struct page **pages;
+
+	pages = kzalloc(npages * (sizeof(struct page *) +
+				  sizeof(struct fuse_page_desc)), flags);
+	*desc = (void *) (pages + npages);
+
+	return pages;
+}
+
 static int fuse_send_open(struct fuse_conn *fc, u64 nodeid, struct file *file,
 			  int opcode, struct fuse_open_out *outargp)
 {
@@ -29,29 +41,36 @@ static int fuse_send_open(struct fuse_conn *fc, u64 nodeid, struct file *file,
 	inarg.flags = file->f_flags & ~(O_CREAT | O_EXCL | O_NOCTTY);
 	if (!fc->atomic_o_trunc)
 		inarg.flags &= ~O_TRUNC;
-	args.in.h.opcode = opcode;
-	args.in.h.nodeid = nodeid;
-	args.in.numargs = 1;
-	args.in.args[0].size = sizeof(inarg);
-	args.in.args[0].value = &inarg;
-	args.out.numargs = 1;
-	args.out.args[0].size = sizeof(*outargp);
-	args.out.args[0].value = outargp;
+	args.opcode = opcode;
+	args.nodeid = nodeid;
+	args.in_numargs = 1;
+	args.in_args[0].size = sizeof(inarg);
+	args.in_args[0].value = &inarg;
+	args.out_numargs = 1;
+	args.out_args[0].size = sizeof(*outargp);
+	args.out_args[0].value = outargp;
 
 	return fuse_simple_request(fc, &args);
 }
 
+struct fuse_release_args {
+	struct fuse_args args;
+	struct fuse_release_in inarg;
+	struct inode *inode;
+};
+
 struct fuse_file *fuse_file_alloc(struct fuse_conn *fc)
 {
 	struct fuse_file *ff;
 
-	ff = kzalloc(sizeof(struct fuse_file), GFP_KERNEL);
+	ff = kzalloc(sizeof(struct fuse_file), GFP_KERNEL_ACCOUNT);
 	if (unlikely(!ff))
 		return NULL;
 
 	ff->fc = fc;
-	ff->reserved_req = fuse_request_alloc(0);
-	if (unlikely(!ff->reserved_req)) {
+	ff->release_args = kzalloc(sizeof(*ff->release_args),
+				   GFP_KERNEL_ACCOUNT);
+	if (!ff->release_args) {
 		kfree(ff);
 		return NULL;
 	}
@@ -69,7 +88,7 @@ struct fuse_file *fuse_file_alloc(struct fuse_conn *fc)
 
 void fuse_file_free(struct fuse_file *ff)
 {
-	fuse_request_free(ff->reserved_req);
+	kfree(ff->release_args);
 	mutex_destroy(&ff->readdir.lock);
 	kfree(ff);
 }
@@ -80,34 +99,31 @@ static struct fuse_file *fuse_file_get(struct fuse_file *ff)
 	return ff;
 }
 
-static void fuse_release_end(struct fuse_conn *fc, struct fuse_req *req)
+static void fuse_release_end(struct fuse_conn *fc, struct fuse_args *args,
+			     int error)
 {
-	iput(req->misc.release.inode);
+	struct fuse_release_args *ra = container_of(args, typeof(*ra), args);
+
+	iput(ra->inode);
+	kfree(ra);
 }
 
 static void fuse_file_put(struct fuse_file *ff, bool sync, bool isdir)
 {
 	if (refcount_dec_and_test(&ff->count)) {
-		struct fuse_req *req = ff->reserved_req;
+		struct fuse_args *args = &ff->release_args->args;
 
 		if (isdir ? ff->fc->no_opendir : ff->fc->no_open) {
-			/*
-			 * Drop the release request when client does not
-			 * implement 'open'
-			 */
-			__clear_bit(FR_BACKGROUND, &req->flags);
-			iput(req->misc.release.inode);
-			fuse_put_request(ff->fc, req);
+			/* Do nothing when client does not implement 'open' */
+			fuse_release_end(ff->fc, args, 0);
 		} else if (sync) {
-			__set_bit(FR_FORCE, &req->flags);
-			__clear_bit(FR_BACKGROUND, &req->flags);
-			fuse_request_send(ff->fc, req);
-			iput(req->misc.release.inode);
-			fuse_put_request(ff->fc, req);
+			fuse_simple_request(ff->fc, args);
+			fuse_release_end(ff->fc, args, 0);
 		} else {
-			req->end = fuse_release_end;
-			__set_bit(FR_BACKGROUND, &req->flags);
-			fuse_request_send_background(ff->fc, req);
+			args->end = fuse_release_end;
+			if (fuse_simple_background(ff->fc, args,
+						   GFP_KERNEL | __GFP_NOFAIL))
+				fuse_release_end(ff->fc, args, -ENOTCONN);
 		}
 		kfree(ff);
 	}
@@ -227,8 +243,7 @@ static void fuse_prepare_release(struct fuse_inode *fi, struct fuse_file *ff,
 				 int flags, int opcode)
 {
 	struct fuse_conn *fc = ff->fc;
-	struct fuse_req *req = ff->reserved_req;
-	struct fuse_release_in *inarg = &req->misc.release.in;
+	struct fuse_release_args *ra = ff->release_args;
 
 	/* Inode is NULL on error path of fuse_create_open() */
 	if (likely(fi)) {
@@ -243,32 +258,33 @@ static void fuse_prepare_release(struct fuse_inode *fi, struct fuse_file *ff,
 
 	wake_up_interruptible_all(&ff->poll_wait);
 
-	inarg->fh = ff->fh;
-	inarg->flags = flags;
-	req->in.h.opcode = opcode;
-	req->in.h.nodeid = ff->nodeid;
-	req->in.numargs = 1;
-	req->in.args[0].size = sizeof(struct fuse_release_in);
-	req->in.args[0].value = inarg;
+	ra->inarg.fh = ff->fh;
+	ra->inarg.flags = flags;
+	ra->args.in_numargs = 1;
+	ra->args.in_args[0].size = sizeof(struct fuse_release_in);
+	ra->args.in_args[0].value = &ra->inarg;
+	ra->args.opcode = opcode;
+	ra->args.nodeid = ff->nodeid;
+	ra->args.force = true;
+	ra->args.nocreds = true;
 }
 
 void fuse_release_common(struct file *file, bool isdir)
 {
 	struct fuse_inode *fi = get_fuse_inode(file_inode(file));
 	struct fuse_file *ff = file->private_data;
-	struct fuse_req *req = ff->reserved_req;
+	struct fuse_release_args *ra = ff->release_args;
 	int opcode = isdir ? FUSE_RELEASEDIR : FUSE_RELEASE;
 
 	fuse_prepare_release(fi, ff, file->f_flags, opcode);
 
 	if (ff->flock) {
-		struct fuse_release_in *inarg = &req->misc.release.in;
-		inarg->release_flags |= FUSE_RELEASE_FLOCK_UNLOCK;
-		inarg->lock_owner = fuse_lock_owner_id(ff->fc,
-						       (fl_owner_t) file);
+		ra->inarg.release_flags |= FUSE_RELEASE_FLOCK_UNLOCK;
+		ra->inarg.lock_owner = fuse_lock_owner_id(ff->fc,
+							  (fl_owner_t) file);
 	}
 	/* Hold inode until release is finished */
-	req->misc.release.inode = igrab(file_inode(file));
+	ra->inode = igrab(file_inode(file));
 
 	/*
 	 * Normally this will send the RELEASE request, however if
@@ -279,7 +295,7 @@ void fuse_release_common(struct file *file, bool isdir)
 	 * synchronous RELEASE is allowed (and desirable) in this case
 	 * because the server can be trusted not to screw up.
 	 */
-	fuse_file_put(ff, ff->fc->destroy_req != NULL, isdir);
+	fuse_file_put(ff, ff->fc->destroy, isdir);
 }
 
 static int fuse_open(struct inode *inode, struct file *file)
@@ -335,19 +351,27 @@ u64 fuse_lock_owner_id(struct fuse_conn *fc, fl_owner_t id)
 	return (u64) v0 + ((u64) v1 << 32);
 }
 
-static struct fuse_req *fuse_find_writeback(struct fuse_inode *fi,
+struct fuse_writepage_args {
+	struct fuse_io_args ia;
+	struct list_head writepages_entry;
+	struct list_head queue_entry;
+	struct fuse_writepage_args *next;
+	struct inode *inode;
+};
+
+static struct fuse_writepage_args *fuse_find_writeback(struct fuse_inode *fi,
 					    pgoff_t idx_from, pgoff_t idx_to)
 {
-	struct fuse_req *req;
+	struct fuse_writepage_args *wpa;
 
-	list_for_each_entry(req, &fi->writepages, writepages_entry) {
+	list_for_each_entry(wpa, &fi->writepages, writepages_entry) {
 		pgoff_t curr_index;
 
-		WARN_ON(get_fuse_inode(req->inode) != fi);
-		curr_index = req->misc.write.in.offset >> PAGE_SHIFT;
-		if (idx_from < curr_index + req->num_pages &&
+		WARN_ON(get_fuse_inode(wpa->inode) != fi);
+		curr_index = wpa->ia.write.in.offset >> PAGE_SHIFT;
+		if (idx_from < curr_index + wpa->ia.ap.num_pages &&
 		    curr_index <= idx_to) {
-			return req;
+			return wpa;
 		}
 	}
 	return NULL;
@@ -383,12 +407,11 @@ static inline bool fuse_page_is_writeback(struct inode *inode, pgoff_t index)
  * Since fuse doesn't rely on the VM writeback tracking, this has to
  * use some other means.
  */
-static int fuse_wait_on_page_writeback(struct inode *inode, pgoff_t index)
+static void fuse_wait_on_page_writeback(struct inode *inode, pgoff_t index)
 {
 	struct fuse_inode *fi = get_fuse_inode(inode);
 
 	wait_event(fi->page_waitq, !fuse_page_is_writeback(inode, index));
-	return 0;
 }
 
 /*
@@ -411,8 +434,8 @@ static int fuse_flush(struct file *file, fl_owner_t id)
 	struct inode *inode = file_inode(file);
 	struct fuse_conn *fc = get_fuse_conn(inode);
 	struct fuse_file *ff = file->private_data;
-	struct fuse_req *req;
 	struct fuse_flush_in inarg;
+	FUSE_ARGS(args);
 	int err;
 
 	if (is_bad_inode(inode))
@@ -433,19 +456,17 @@ static int fuse_flush(struct file *file, fl_owner_t id)
 	if (err)
 		return err;
 
-	req = fuse_get_req_nofail_nopages(fc, file);
 	memset(&inarg, 0, sizeof(inarg));
 	inarg.fh = ff->fh;
 	inarg.lock_owner = fuse_lock_owner_id(fc, id);
-	req->in.h.opcode = FUSE_FLUSH;
-	req->in.h.nodeid = get_node_id(inode);
-	req->in.numargs = 1;
-	req->in.args[0].size = sizeof(inarg);
-	req->in.args[0].value = &inarg;
-	__set_bit(FR_FORCE, &req->flags);
-	fuse_request_send(fc, req);
-	err = req->out.h.error;
-	fuse_put_request(fc, req);
+	args.opcode = FUSE_FLUSH;
+	args.nodeid = get_node_id(inode);
+	args.in_numargs = 1;
+	args.in_args[0].size = sizeof(inarg);
+	args.in_args[0].value = &inarg;
+	args.force = true;
+
+	err = fuse_simple_request(fc, &args);
 	if (err == -ENOSYS) {
 		fc->no_flush = 1;
 		err = 0;
@@ -465,11 +486,11 @@ int fuse_fsync_common(struct file *file, loff_t start, loff_t end,
 	memset(&inarg, 0, sizeof(inarg));
 	inarg.fh = ff->fh;
 	inarg.fsync_flags = datasync ? FUSE_FSYNC_FDATASYNC : 0;
-	args.in.h.opcode = opcode;
-	args.in.h.nodeid = get_node_id(inode);
-	args.in.numargs = 1;
-	args.in.args[0].size = sizeof(inarg);
-	args.in.args[0].value = &inarg;
+	args.opcode = opcode;
+	args.nodeid = get_node_id(inode);
+	args.in_numargs = 1;
+	args.in_args[0].size = sizeof(inarg);
+	args.in_args[0].value = &inarg;
 	return fuse_simple_request(fc, &args);
 }
 
@@ -523,35 +544,35 @@ static int fuse_fsync(struct file *file, loff_t start, loff_t end,
 	return err;
 }
 
-void fuse_read_fill(struct fuse_req *req, struct file *file, loff_t pos,
-		    size_t count, int opcode)
+void fuse_read_args_fill(struct fuse_io_args *ia, struct file *file, loff_t pos,
+			 size_t count, int opcode)
 {
-	struct fuse_read_in *inarg = &req->misc.read.in;
 	struct fuse_file *ff = file->private_data;
+	struct fuse_args *args = &ia->ap.args;
 
-	inarg->fh = ff->fh;
-	inarg->offset = pos;
-	inarg->size = count;
-	inarg->flags = file->f_flags;
-	req->in.h.opcode = opcode;
-	req->in.h.nodeid = ff->nodeid;
-	req->in.numargs = 1;
-	req->in.args[0].size = sizeof(struct fuse_read_in);
-	req->in.args[0].value = inarg;
-	req->out.argvar = 1;
-	req->out.numargs = 1;
-	req->out.args[0].size = count;
+	ia->read.in.fh = ff->fh;
+	ia->read.in.offset = pos;
+	ia->read.in.size = count;
+	ia->read.in.flags = file->f_flags;
+	args->opcode = opcode;
+	args->nodeid = ff->nodeid;
+	args->in_numargs = 1;
+	args->in_args[0].size = sizeof(ia->read.in);
+	args->in_args[0].value = &ia->read.in;
+	args->out_argvar = true;
+	args->out_numargs = 1;
+	args->out_args[0].size = count;
 }
 
-static void fuse_release_user_pages(struct fuse_req *req, bool should_dirty)
+static void fuse_release_user_pages(struct fuse_args_pages *ap,
+				    bool should_dirty)
 {
-	unsigned i;
+	unsigned int i;
 
-	for (i = 0; i < req->num_pages; i++) {
-		struct page *page = req->pages[i];
+	for (i = 0; i < ap->num_pages; i++) {
 		if (should_dirty)
-			set_page_dirty_lock(page);
-		put_page(page);
+			set_page_dirty_lock(ap->pages[i]);
+		put_page(ap->pages[i]);
 	}
 }
 
@@ -621,64 +642,94 @@ static void fuse_aio_complete(struct fuse_io_priv *io, int err, ssize_t pos)
 	kref_put(&io->refcnt, fuse_io_release);
 }
 
-static void fuse_aio_complete_req(struct fuse_conn *fc, struct fuse_req *req)
+static struct fuse_io_args *fuse_io_alloc(struct fuse_io_priv *io,
+					  unsigned int npages)
+{
+	struct fuse_io_args *ia;
+
+	ia = kzalloc(sizeof(*ia), GFP_KERNEL);
+	if (ia) {
+		ia->io = io;
+		ia->ap.pages = fuse_pages_alloc(npages, GFP_KERNEL,
+						&ia->ap.descs);
+		if (!ia->ap.pages) {
+			kfree(ia);
+			ia = NULL;
+		}
+	}
+	return ia;
+}
+
+static void fuse_io_free(struct fuse_io_args *ia)
+{
+	kfree(ia->ap.pages);
+	kfree(ia);
+}
+
+static void fuse_aio_complete_req(struct fuse_conn *fc, struct fuse_args *args,
+				  int err)
 {
-	struct fuse_io_priv *io = req->io;
+	struct fuse_io_args *ia = container_of(args, typeof(*ia), ap.args);
+	struct fuse_io_priv *io = ia->io;
 	ssize_t pos = -1;
 
-	fuse_release_user_pages(req, io->should_dirty);
+	fuse_release_user_pages(&ia->ap, io->should_dirty);
 
-	if (io->write) {
-		if (req->misc.write.in.size != req->misc.write.out.size)
-			pos = req->misc.write.in.offset - io->offset +
-				req->misc.write.out.size;
+	if (err) {
+		/* Nothing */
+	} else if (io->write) {
+		if (ia->write.out.size > ia->write.in.size) {
+			err = -EIO;
+		} else if (ia->write.in.size != ia->write.out.size) {
+			pos = ia->write.in.offset - io->offset +
+				ia->write.out.size;
+		}
 	} else {
-		if (req->misc.read.in.size != req->out.args[0].size)
-			pos = req->misc.read.in.offset - io->offset +
-				req->out.args[0].size;
+		u32 outsize = args->out_args[0].size;
+
+		if (ia->read.in.size != outsize)
+			pos = ia->read.in.offset - io->offset + outsize;
 	}
 
-	fuse_aio_complete(io, req->out.h.error, pos);
+	fuse_aio_complete(io, err, pos);
+	fuse_io_free(ia);
 }
 
-static size_t fuse_async_req_send(struct fuse_conn *fc, struct fuse_req *req,
-		size_t num_bytes, struct fuse_io_priv *io)
+static ssize_t fuse_async_req_send(struct fuse_conn *fc,
+				   struct fuse_io_args *ia, size_t num_bytes)
 {
+	ssize_t err;
+	struct fuse_io_priv *io = ia->io;
+
 	spin_lock(&io->lock);
 	kref_get(&io->refcnt);
 	io->size += num_bytes;
 	io->reqs++;
 	spin_unlock(&io->lock);
 
-	req->io = io;
-	req->end = fuse_aio_complete_req;
+	ia->ap.args.end = fuse_aio_complete_req;
+	err = fuse_simple_background(fc, &ia->ap.args, GFP_KERNEL);
 
-	__fuse_get_request(req);
-	fuse_request_send_background(fc, req);
-
-	return num_bytes;
+	return err ?: num_bytes;
 }
 
-static size_t fuse_send_read(struct fuse_req *req, struct fuse_io_priv *io,
-			     loff_t pos, size_t count, fl_owner_t owner)
+static ssize_t fuse_send_read(struct fuse_io_args *ia, loff_t pos, size_t count,
+			      fl_owner_t owner)
 {
-	struct file *file = io->iocb->ki_filp;
+	struct file *file = ia->io->iocb->ki_filp;
 	struct fuse_file *ff = file->private_data;
 	struct fuse_conn *fc = ff->fc;
 
-	fuse_read_fill(req, file, pos, count, FUSE_READ);
+	fuse_read_args_fill(ia, file, pos, count, FUSE_READ);
 	if (owner != NULL) {
-		struct fuse_read_in *inarg = &req->misc.read.in;
-
-		inarg->read_flags |= FUSE_READ_LOCKOWNER;
-		inarg->lock_owner = fuse_lock_owner_id(fc, owner);
+		ia->read.in.read_flags |= FUSE_READ_LOCKOWNER;
+		ia->read.in.lock_owner = fuse_lock_owner_id(fc, owner);
 	}
 
-	if (io->async)
-		return fuse_async_req_send(fc, req, count, io);
+	if (ia->io->async)
+		return fuse_async_req_send(fc, ia, count);
 
-	fuse_request_send(fc, req);
-	return req->out.args[0].size;
+	return fuse_simple_request(fc, &ia->ap.args);
 }
 
 static void fuse_read_update_size(struct inode *inode, loff_t size,
@@ -696,10 +747,9 @@ static void fuse_read_update_size(struct inode *inode, loff_t size,
 	spin_unlock(&fi->lock);
 }
 
-static void fuse_short_read(struct fuse_req *req, struct inode *inode,
-			    u64 attr_ver)
+static void fuse_short_read(struct inode *inode, u64 attr_ver, size_t num_read,
+			    struct fuse_args_pages *ap)
 {
-	size_t num_read = req->out.args[0].size;
 	struct fuse_conn *fc = get_fuse_conn(inode);
 
 	if (fc->writeback_cache) {
@@ -712,28 +762,31 @@ static void fuse_short_read(struct fuse_req *req, struct inode *inode,
 		int start_idx = num_read >> PAGE_SHIFT;
 		size_t off = num_read & (PAGE_SIZE - 1);
 
-		for (i = start_idx; i < req->num_pages; i++) {
-			zero_user_segment(req->pages[i], off, PAGE_SIZE);
+		for (i = start_idx; i < ap->num_pages; i++) {
+			zero_user_segment(ap->pages[i], off, PAGE_SIZE);
 			off = 0;
 		}
 	} else {
-		loff_t pos = page_offset(req->pages[0]) + num_read;
+		loff_t pos = page_offset(ap->pages[0]) + num_read;
 		fuse_read_update_size(inode, pos, attr_ver);
 	}
 }
 
 static int fuse_do_readpage(struct file *file, struct page *page)
 {
-	struct kiocb iocb;
-	struct fuse_io_priv io;
 	struct inode *inode = page->mapping->host;
 	struct fuse_conn *fc = get_fuse_conn(inode);
-	struct fuse_req *req;
-	size_t num_read;
 	loff_t pos = page_offset(page);
-	size_t count = PAGE_SIZE;
+	struct fuse_page_desc desc = { .length = PAGE_SIZE };
+	struct fuse_io_args ia = {
+		.ap.args.page_zeroing = true,
+		.ap.args.out_pages = true,
+		.ap.num_pages = 1,
+		.ap.pages = &page,
+		.ap.descs = &desc,
+	};
+	ssize_t res;
 	u64 attr_ver;
-	int err;
 
 	/*
 	 * Page writeback can extend beyond the lifetime of the
@@ -742,35 +795,21 @@ static int fuse_do_readpage(struct file *file, struct page *page)
 	 */
 	fuse_wait_on_page_writeback(inode, page->index);
 
-	req = fuse_get_req(fc, 1);
-	if (IS_ERR(req))
-		return PTR_ERR(req);
-
 	attr_ver = fuse_get_attr_version(fc);
 
-	req->out.page_zeroing = 1;
-	req->out.argpages = 1;
-	req->num_pages = 1;
-	req->pages[0] = page;
-	req->page_descs[0].length = count;
-	init_sync_kiocb(&iocb, file);
-	io = (struct fuse_io_priv) FUSE_IO_PRIV_SYNC(&iocb);
-	num_read = fuse_send_read(req, &io, pos, count, NULL);
-	err = req->out.h.error;
-
-	if (!err) {
-		/*
-		 * Short read means EOF.  If file size is larger, truncate it
-		 */
-		if (num_read < count)
-			fuse_short_read(req, inode, attr_ver);
-
-		SetPageUptodate(page);
-	}
+	fuse_read_args_fill(&ia, file, pos, desc.length, FUSE_READ);
+	res = fuse_simple_request(fc, &ia.ap.args);
+	if (res < 0)
+		return res;
+	/*
+	 * Short read means EOF.  If file size is larger, truncate it
+	 */
+	if (res < desc.length)
+		fuse_short_read(inode, attr_ver, res, &ia.ap);
 
-	fuse_put_request(fc, req);
+	SetPageUptodate(page);
 
-	return err;
+	return 0;
 }
 
 static int fuse_readpage(struct file *file, struct page *page)
@@ -789,15 +828,18 @@ static int fuse_readpage(struct file *file, struct page *page)
 	return err;
 }
 
-static void fuse_readpages_end(struct fuse_conn *fc, struct fuse_req *req)
+static void fuse_readpages_end(struct fuse_conn *fc, struct fuse_args *args,
+			       int err)
 {
 	int i;
-	size_t count = req->misc.read.in.size;
-	size_t num_read = req->out.args[0].size;
+	struct fuse_io_args *ia = container_of(args, typeof(*ia), ap.args);
+	struct fuse_args_pages *ap = &ia->ap;
+	size_t count = ia->read.in.size;
+	size_t num_read = args->out_args[0].size;
 	struct address_space *mapping = NULL;
 
-	for (i = 0; mapping == NULL && i < req->num_pages; i++)
-		mapping = req->pages[i]->mapping;
+	for (i = 0; mapping == NULL && i < ap->num_pages; i++)
+		mapping = ap->pages[i]->mapping;
 
 	if (mapping) {
 		struct inode *inode = mapping->host;
@@ -805,93 +847,97 @@ static void fuse_readpages_end(struct fuse_conn *fc, struct fuse_req *req)
 		/*
 		 * Short read means EOF. If file size is larger, truncate it
 		 */
-		if (!req->out.h.error && num_read < count)
-			fuse_short_read(req, inode, req->misc.read.attr_ver);
+		if (!err && num_read < count)
+			fuse_short_read(inode, ia->read.attr_ver, num_read, ap);
 
 		fuse_invalidate_atime(inode);
 	}
 
-	for (i = 0; i < req->num_pages; i++) {
-		struct page *page = req->pages[i];
-		if (!req->out.h.error)
+	for (i = 0; i < ap->num_pages; i++) {
+		struct page *page = ap->pages[i];
+
+		if (!err)
 			SetPageUptodate(page);
 		else
 			SetPageError(page);
 		unlock_page(page);
 		put_page(page);
 	}
-	if (req->ff)
-		fuse_file_put(req->ff, false, false);
+	if (ia->ff)
+		fuse_file_put(ia->ff, false, false);
+
+	fuse_io_free(ia);
 }
 
-static void fuse_send_readpages(struct fuse_req *req, struct file *file)
+static void fuse_send_readpages(struct fuse_io_args *ia, struct file *file)
 {
 	struct fuse_file *ff = file->private_data;
 	struct fuse_conn *fc = ff->fc;
-	loff_t pos = page_offset(req->pages[0]);
-	size_t count = req->num_pages << PAGE_SHIFT;
-
-	req->out.argpages = 1;
-	req->out.page_zeroing = 1;
-	req->out.page_replace = 1;
-	fuse_read_fill(req, file, pos, count, FUSE_READ);
-	req->misc.read.attr_ver = fuse_get_attr_version(fc);
+	struct fuse_args_pages *ap = &ia->ap;
+	loff_t pos = page_offset(ap->pages[0]);
+	size_t count = ap->num_pages << PAGE_SHIFT;
+	int err;
+
+	ap->args.out_pages = true;
+	ap->args.page_zeroing = true;
+	ap->args.page_replace = true;
+	fuse_read_args_fill(ia, file, pos, count, FUSE_READ);
+	ia->read.attr_ver = fuse_get_attr_version(fc);
 	if (fc->async_read) {
-		req->ff = fuse_file_get(ff);
-		req->end = fuse_readpages_end;
-		fuse_request_send_background(fc, req);
+		ia->ff = fuse_file_get(ff);
+		ap->args.end = fuse_readpages_end;
+		err = fuse_simple_background(fc, &ap->args, GFP_KERNEL);
+		if (!err)
+			return;
 	} else {
-		fuse_request_send(fc, req);
-		fuse_readpages_end(fc, req);
-		fuse_put_request(fc, req);
+		err = fuse_simple_request(fc, &ap->args);
 	}
+	fuse_readpages_end(fc, &ap->args, err);
 }
 
 struct fuse_fill_data {
-	struct fuse_req *req;
+	struct fuse_io_args *ia;
 	struct file *file;
 	struct inode *inode;
-	unsigned nr_pages;
+	unsigned int nr_pages;
+	unsigned int max_pages;
 };
 
 static int fuse_readpages_fill(void *_data, struct page *page)
 {
 	struct fuse_fill_data *data = _data;
-	struct fuse_req *req = data->req;
+	struct fuse_io_args *ia = data->ia;
+	struct fuse_args_pages *ap = &ia->ap;
 	struct inode *inode = data->inode;
 	struct fuse_conn *fc = get_fuse_conn(inode);
 
 	fuse_wait_on_page_writeback(inode, page->index);
 
-	if (req->num_pages &&
-	    (req->num_pages == fc->max_pages ||
-	     (req->num_pages + 1) * PAGE_SIZE > fc->max_read ||
-	     req->pages[req->num_pages - 1]->index + 1 != page->index)) {
-		unsigned int nr_alloc = min_t(unsigned int, data->nr_pages,
-					      fc->max_pages);
-		fuse_send_readpages(req, data->file);
-		if (fc->async_read)
-			req = fuse_get_req_for_background(fc, nr_alloc);
-		else
-			req = fuse_get_req(fc, nr_alloc);
-
-		data->req = req;
-		if (IS_ERR(req)) {
+	if (ap->num_pages &&
+	    (ap->num_pages == fc->max_pages ||
+	     (ap->num_pages + 1) * PAGE_SIZE > fc->max_read ||
+	     ap->pages[ap->num_pages - 1]->index + 1 != page->index)) {
+		data->max_pages = min_t(unsigned int, data->nr_pages,
+					fc->max_pages);
+		fuse_send_readpages(ia, data->file);
+		data->ia = ia = fuse_io_alloc(NULL, data->max_pages);
+		if (!ia) {
 			unlock_page(page);
-			return PTR_ERR(req);
+			return -ENOMEM;
 		}
+		ap = &ia->ap;
 	}
 
-	if (WARN_ON(req->num_pages >= req->max_pages)) {
+	if (WARN_ON(ap->num_pages >= data->max_pages)) {
 		unlock_page(page);
-		fuse_put_request(fc, req);
+		fuse_io_free(ia);
 		return -EIO;
 	}
 
 	get_page(page);
-	req->pages[req->num_pages] = page;
-	req->page_descs[req->num_pages].length = PAGE_SIZE;
-	req->num_pages++;
+	ap->pages[ap->num_pages] = page;
+	ap->descs[ap->num_pages].length = PAGE_SIZE;
+	ap->num_pages++;
 	data->nr_pages--;
 	return 0;
 }
@@ -903,7 +949,6 @@ static int fuse_readpages(struct file *file, struct address_space *mapping,
 	struct fuse_conn *fc = get_fuse_conn(inode);
 	struct fuse_fill_data data;
 	int err;
-	unsigned int nr_alloc = min_t(unsigned int, nr_pages, fc->max_pages);
 
 	err = -EIO;
 	if (is_bad_inode(inode))
@@ -911,21 +956,20 @@ static int fuse_readpages(struct file *file, struct address_space *mapping,
 
 	data.file = file;
 	data.inode = inode;
-	if (fc->async_read)
-		data.req = fuse_get_req_for_background(fc, nr_alloc);
-	else
-		data.req = fuse_get_req(fc, nr_alloc);
 	data.nr_pages = nr_pages;
-	err = PTR_ERR(data.req);
-	if (IS_ERR(data.req))
+	data.max_pages = min_t(unsigned int, nr_pages, fc->max_pages);
+;
+	data.ia = fuse_io_alloc(NULL, data.max_pages);
+	err = -ENOMEM;
+	if (!data.ia)
 		goto out;
 
 	err = read_cache_pages(mapping, pages, fuse_readpages_fill, &data);
 	if (!err) {
-		if (data.req->num_pages)
-			fuse_send_readpages(data.req, file);
+		if (data.ia->ap.num_pages)
+			fuse_send_readpages(data.ia, file);
 		else
-			fuse_put_request(fc, data.req);
+			fuse_io_free(data.ia);
 	}
 out:
 	return err;
@@ -952,54 +996,65 @@ static ssize_t fuse_cache_read_iter(struct kiocb *iocb, struct iov_iter *to)
 	return generic_file_read_iter(iocb, to);
 }
 
-static void fuse_write_fill(struct fuse_req *req, struct fuse_file *ff,
-			    loff_t pos, size_t count)
+static void fuse_write_args_fill(struct fuse_io_args *ia, struct fuse_file *ff,
+				 loff_t pos, size_t count)
 {
-	struct fuse_write_in *inarg = &req->misc.write.in;
-	struct fuse_write_out *outarg = &req->misc.write.out;
+	struct fuse_args *args = &ia->ap.args;
 
-	inarg->fh = ff->fh;
-	inarg->offset = pos;
-	inarg->size = count;
-	req->in.h.opcode = FUSE_WRITE;
-	req->in.h.nodeid = ff->nodeid;
-	req->in.numargs = 2;
+	ia->write.in.fh = ff->fh;
+	ia->write.in.offset = pos;
+	ia->write.in.size = count;
+	args->opcode = FUSE_WRITE;
+	args->nodeid = ff->nodeid;
+	args->in_numargs = 2;
 	if (ff->fc->minor < 9)
-		req->in.args[0].size = FUSE_COMPAT_WRITE_IN_SIZE;
+		args->in_args[0].size = FUSE_COMPAT_WRITE_IN_SIZE;
 	else
-		req->in.args[0].size = sizeof(struct fuse_write_in);
-	req->in.args[0].value = inarg;
-	req->in.args[1].size = count;
-	req->out.numargs = 1;
-	req->out.args[0].size = sizeof(struct fuse_write_out);
-	req->out.args[0].value = outarg;
+		args->in_args[0].size = sizeof(ia->write.in);
+	args->in_args[0].value = &ia->write.in;
+	args->in_args[1].size = count;
+	args->out_numargs = 1;
+	args->out_args[0].size = sizeof(ia->write.out);
+	args->out_args[0].value = &ia->write.out;
 }
 
-static size_t fuse_send_write(struct fuse_req *req, struct fuse_io_priv *io,
-			      loff_t pos, size_t count, fl_owner_t owner)
+static unsigned int fuse_write_flags(struct kiocb *iocb)
 {
-	struct kiocb *iocb = io->iocb;
+	unsigned int flags = iocb->ki_filp->f_flags;
+
+	if (iocb->ki_flags & IOCB_DSYNC)
+		flags |= O_DSYNC;
+	if (iocb->ki_flags & IOCB_SYNC)
+		flags |= O_SYNC;
+
+	return flags;
+}
+
+static ssize_t fuse_send_write(struct fuse_io_args *ia, loff_t pos,
+			       size_t count, fl_owner_t owner)
+{
+	struct kiocb *iocb = ia->io->iocb;
 	struct file *file = iocb->ki_filp;
 	struct fuse_file *ff = file->private_data;
 	struct fuse_conn *fc = ff->fc;
-	struct fuse_write_in *inarg = &req->misc.write.in;
+	struct fuse_write_in *inarg = &ia->write.in;
+	ssize_t err;
 
-	fuse_write_fill(req, ff, pos, count);
-	inarg->flags = file->f_flags;
-	if (iocb->ki_flags & IOCB_DSYNC)
-		inarg->flags |= O_DSYNC;
-	if (iocb->ki_flags & IOCB_SYNC)
-		inarg->flags |= O_SYNC;
+	fuse_write_args_fill(ia, ff, pos, count);
+	inarg->flags = fuse_write_flags(iocb);
 	if (owner != NULL) {
 		inarg->write_flags |= FUSE_WRITE_LOCKOWNER;
 		inarg->lock_owner = fuse_lock_owner_id(fc, owner);
 	}
 
-	if (io->async)
-		return fuse_async_req_send(fc, req, count, io);
+	if (ia->io->async)
+		return fuse_async_req_send(fc, ia, count);
+
+	err = fuse_simple_request(fc, &ia->ap.args);
+	if (!err && ia->write.out.size > count)
+		err = -EIO;
 
-	fuse_request_send(fc, req);
-	return req->misc.write.out.size;
+	return err ?: ia->write.out.size;
 }
 
 bool fuse_write_update_size(struct inode *inode, loff_t pos)
@@ -1019,26 +1074,31 @@ bool fuse_write_update_size(struct inode *inode, loff_t pos)
 	return ret;
 }
 
-static size_t fuse_send_write_pages(struct fuse_req *req, struct kiocb *iocb,
-				    struct inode *inode, loff_t pos,
-				    size_t count)
+static ssize_t fuse_send_write_pages(struct fuse_io_args *ia,
+				     struct kiocb *iocb, struct inode *inode,
+				     loff_t pos, size_t count)
 {
-	size_t res;
-	unsigned offset;
-	unsigned i;
-	struct fuse_io_priv io = FUSE_IO_PRIV_SYNC(iocb);
+	struct fuse_args_pages *ap = &ia->ap;
+	struct file *file = iocb->ki_filp;
+	struct fuse_file *ff = file->private_data;
+	struct fuse_conn *fc = ff->fc;
+	unsigned int offset, i;
+	int err;
 
-	for (i = 0; i < req->num_pages; i++)
-		fuse_wait_on_page_writeback(inode, req->pages[i]->index);
+	for (i = 0; i < ap->num_pages; i++)
+		fuse_wait_on_page_writeback(inode, ap->pages[i]->index);
 
-	res = fuse_send_write(req, &io, pos, count, NULL);
+	fuse_write_args_fill(ia, ff, pos, count);
+	ia->write.in.flags = fuse_write_flags(iocb);
 
-	offset = req->page_descs[0].offset;
-	count = res;
-	for (i = 0; i < req->num_pages; i++) {
-		struct page *page = req->pages[i];
+	err = fuse_simple_request(fc, &ap->args);
 
-		if (!req->out.h.error && !offset && count >= PAGE_SIZE)
+	offset = ap->descs[0].offset;
+	count = ia->write.out.size;
+	for (i = 0; i < ap->num_pages; i++) {
+		struct page *page = ap->pages[i];
+
+		if (!err && !offset && count >= PAGE_SIZE)
 			SetPageUptodate(page);
 
 		if (count > PAGE_SIZE - offset)
@@ -1051,20 +1111,21 @@ static size_t fuse_send_write_pages(struct fuse_req *req, struct kiocb *iocb,
 		put_page(page);
 	}
 
-	return res;
+	return err;
 }
 
-static ssize_t fuse_fill_write_pages(struct fuse_req *req,
-			       struct address_space *mapping,
-			       struct iov_iter *ii, loff_t pos)
+static ssize_t fuse_fill_write_pages(struct fuse_args_pages *ap,
+				     struct address_space *mapping,
+				     struct iov_iter *ii, loff_t pos,
+				     unsigned int max_pages)
 {
 	struct fuse_conn *fc = get_fuse_conn(mapping->host);
 	unsigned offset = pos & (PAGE_SIZE - 1);
 	size_t count = 0;
 	int err;
 
-	req->in.argpages = 1;
-	req->page_descs[0].offset = offset;
+	ap->args.in_pages = true;
+	ap->descs[0].offset = offset;
 
 	do {
 		size_t tmp;
@@ -1100,9 +1161,9 @@ static ssize_t fuse_fill_write_pages(struct fuse_req *req,
 		}
 
 		err = 0;
-		req->pages[req->num_pages] = page;
-		req->page_descs[req->num_pages].length = tmp;
-		req->num_pages++;
+		ap->pages[ap->num_pages] = page;
+		ap->descs[ap->num_pages].length = tmp;
+		ap->num_pages++;
 
 		count += tmp;
 		pos += tmp;
@@ -1113,7 +1174,7 @@ static ssize_t fuse_fill_write_pages(struct fuse_req *req,
 		if (!fc->big_writes)
 			break;
 	} while (iov_iter_count(ii) && count < fc->max_write &&
-		 req->num_pages < req->max_pages && offset == 0);
+		 ap->num_pages < max_pages && offset == 0);
 
 	return count > 0 ? count : err;
 }
@@ -1141,27 +1202,27 @@ static ssize_t fuse_perform_write(struct kiocb *iocb,
 		set_bit(FUSE_I_SIZE_UNSTABLE, &fi->state);
 
 	do {
-		struct fuse_req *req;
 		ssize_t count;
+		struct fuse_io_args ia = {};
+		struct fuse_args_pages *ap = &ia.ap;
 		unsigned int nr_pages = fuse_wr_pages(pos, iov_iter_count(ii),
 						      fc->max_pages);
 
-		req = fuse_get_req(fc, nr_pages);
-		if (IS_ERR(req)) {
-			err = PTR_ERR(req);
+		ap->pages = fuse_pages_alloc(nr_pages, GFP_KERNEL, &ap->descs);
+		if (!ap->pages) {
+			err = -ENOMEM;
 			break;
 		}
 
-		count = fuse_fill_write_pages(req, mapping, ii, pos);
+		count = fuse_fill_write_pages(ap, mapping, ii, pos, nr_pages);
 		if (count <= 0) {
 			err = count;
 		} else {
-			size_t num_written;
-
-			num_written = fuse_send_write_pages(req, iocb, inode,
-							    pos, count);
-			err = req->out.h.error;
+			err = fuse_send_write_pages(&ia, iocb, inode,
+						    pos, count);
 			if (!err) {
+				size_t num_written = ia.write.out.size;
+
 				res += num_written;
 				pos += num_written;
 
@@ -1170,7 +1231,7 @@ static ssize_t fuse_perform_write(struct kiocb *iocb,
 					err = -EIO;
 			}
 		}
-		fuse_put_request(fc, req);
+		kfree(ap->pages);
 	} while (!err && iov_iter_count(ii));
 
 	if (res > 0)
@@ -1258,14 +1319,14 @@ static ssize_t fuse_cache_write_iter(struct kiocb *iocb, struct iov_iter *from)
 	return written ? written : err;
 }
 
-static inline void fuse_page_descs_length_init(struct fuse_req *req,
-		unsigned index, unsigned nr_pages)
+static inline void fuse_page_descs_length_init(struct fuse_page_desc *descs,
+					       unsigned int index,
+					       unsigned int nr_pages)
 {
 	int i;
 
 	for (i = index; i < index + nr_pages; i++)
-		req->page_descs[i].length = PAGE_SIZE -
-			req->page_descs[i].offset;
+		descs[i].length = PAGE_SIZE - descs[i].offset;
 }
 
 static inline unsigned long fuse_get_user_addr(const struct iov_iter *ii)
@@ -1279,8 +1340,9 @@ static inline size_t fuse_get_frag_size(const struct iov_iter *ii,
 	return min(iov_iter_single_seg_count(ii), max_size);
 }
 
-static int fuse_get_user_pages(struct fuse_req *req, struct iov_iter *ii,
-			       size_t *nbytesp, int write)
+static int fuse_get_user_pages(struct fuse_args_pages *ap, struct iov_iter *ii,
+			       size_t *nbytesp, int write,
+			       unsigned int max_pages)
 {
 	size_t nbytes = 0;  /* # bytes already packed in req */
 	ssize_t ret = 0;
@@ -1291,21 +1353,21 @@ static int fuse_get_user_pages(struct fuse_req *req, struct iov_iter *ii,
 		size_t frag_size = fuse_get_frag_size(ii, *nbytesp);
 
 		if (write)
-			req->in.args[1].value = (void *) user_addr;
+			ap->args.in_args[1].value = (void *) user_addr;
 		else
-			req->out.args[0].value = (void *) user_addr;
+			ap->args.out_args[0].value = (void *) user_addr;
 
 		iov_iter_advance(ii, frag_size);
 		*nbytesp = frag_size;
 		return 0;
 	}
 
-	while (nbytes < *nbytesp && req->num_pages < req->max_pages) {
+	while (nbytes < *nbytesp && ap->num_pages < max_pages) {
 		unsigned npages;
 		size_t start;
-		ret = iov_iter_get_pages(ii, &req->pages[req->num_pages],
+		ret = iov_iter_get_pages(ii, &ap->pages[ap->num_pages],
 					*nbytesp - nbytes,
-					req->max_pages - req->num_pages,
+					max_pages - ap->num_pages,
 					&start);
 		if (ret < 0)
 			break;
@@ -1316,18 +1378,18 @@ static int fuse_get_user_pages(struct fuse_req *req, struct iov_iter *ii,
 		ret += start;
 		npages = (ret + PAGE_SIZE - 1) / PAGE_SIZE;
 
-		req->page_descs[req->num_pages].offset = start;
-		fuse_page_descs_length_init(req, req->num_pages, npages);
+		ap->descs[ap->num_pages].offset = start;
+		fuse_page_descs_length_init(ap->descs, ap->num_pages, npages);
 
-		req->num_pages += npages;
-		req->page_descs[req->num_pages - 1].length -=
+		ap->num_pages += npages;
+		ap->descs[ap->num_pages - 1].length -=
 			(PAGE_SIZE - ret) & (PAGE_SIZE - 1);
 	}
 
 	if (write)
-		req->in.argpages = 1;
+		ap->args.in_pages = 1;
 	else
-		req->out.argpages = 1;
+		ap->args.out_pages = 1;
 
 	*nbytesp = nbytes;
 
@@ -1349,17 +1411,16 @@ ssize_t fuse_direct_io(struct fuse_io_priv *io, struct iov_iter *iter,
 	pgoff_t idx_from = pos >> PAGE_SHIFT;
 	pgoff_t idx_to = (pos + count - 1) >> PAGE_SHIFT;
 	ssize_t res = 0;
-	struct fuse_req *req;
 	int err = 0;
+	struct fuse_io_args *ia;
+	unsigned int max_pages;
 
-	if (io->async)
-		req = fuse_get_req_for_background(fc, iov_iter_npages(iter,
-								fc->max_pages));
-	else
-		req = fuse_get_req(fc, iov_iter_npages(iter, fc->max_pages));
-	if (IS_ERR(req))
-		return PTR_ERR(req);
+	max_pages = iov_iter_npages(iter, fc->max_pages);
+	ia = fuse_io_alloc(io, max_pages);
+	if (!ia)
+		return -ENOMEM;
 
+	ia->io = io;
 	if (!cuse && fuse_range_is_writeback(inode, idx_from, idx_to)) {
 		if (!write)
 			inode_lock(inode);
@@ -1370,54 +1431,49 @@ ssize_t fuse_direct_io(struct fuse_io_priv *io, struct iov_iter *iter,
 
 	io->should_dirty = !write && iter_is_iovec(iter);
 	while (count) {
-		size_t nres;
+		ssize_t nres;
 		fl_owner_t owner = current->files;
 		size_t nbytes = min(count, nmax);
-		err = fuse_get_user_pages(req, iter, &nbytes, write);
+
+		err = fuse_get_user_pages(&ia->ap, iter, &nbytes, write,
+					  max_pages);
 		if (err && !nbytes)
 			break;
 
 		if (write) {
-			if (!capable(CAP_FSETID)) {
-				struct fuse_write_in *inarg;
+			if (!capable(CAP_FSETID))
+				ia->write.in.write_flags |= FUSE_WRITE_KILL_PRIV;
 
-				inarg = &req->misc.write.in;
-				inarg->write_flags |= FUSE_WRITE_KILL_PRIV;
-			}
-			nres = fuse_send_write(req, io, pos, nbytes, owner);
+			nres = fuse_send_write(ia, pos, nbytes, owner);
 		} else {
-			nres = fuse_send_read(req, io, pos, nbytes, owner);
+			nres = fuse_send_read(ia, pos, nbytes, owner);
 		}
 
-		if (!io->async)
-			fuse_release_user_pages(req, io->should_dirty);
-		if (req->out.h.error) {
-			err = req->out.h.error;
-			break;
-		} else if (nres > nbytes) {
-			res = 0;
-			err = -EIO;
+		if (!io->async || nres < 0) {
+			fuse_release_user_pages(&ia->ap, io->should_dirty);
+			fuse_io_free(ia);
+		}
+		ia = NULL;
+		if (nres < 0) {
+			err = nres;
 			break;
 		}
+		WARN_ON(nres > nbytes);
+
 		count -= nres;
 		res += nres;
 		pos += nres;
 		if (nres != nbytes)
 			break;
 		if (count) {
-			fuse_put_request(fc, req);
-			if (io->async)
-				req = fuse_get_req_for_background(fc,
-					iov_iter_npages(iter, fc->max_pages));
-			else
-				req = fuse_get_req(fc, iov_iter_npages(iter,
-								fc->max_pages));
-			if (IS_ERR(req))
+			max_pages = iov_iter_npages(iter, fc->max_pages);
+			ia = fuse_io_alloc(io, max_pages);
+			if (!ia)
 				break;
 		}
 	}
-	if (!IS_ERR(req))
-		fuse_put_request(fc, req);
+	if (ia)
+		fuse_io_free(ia);
 	if (res > 0)
 		*ppos = pos;
 
@@ -1509,45 +1565,53 @@ static ssize_t fuse_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
 		return fuse_direct_write_iter(iocb, from);
 }
 
-static void fuse_writepage_free(struct fuse_conn *fc, struct fuse_req *req)
+static void fuse_writepage_free(struct fuse_writepage_args *wpa)
 {
+	struct fuse_args_pages *ap = &wpa->ia.ap;
 	int i;
 
-	for (i = 0; i < req->num_pages; i++)
-		__free_page(req->pages[i]);
+	for (i = 0; i < ap->num_pages; i++)
+		__free_page(ap->pages[i]);
+
+	if (wpa->ia.ff)
+		fuse_file_put(wpa->ia.ff, false, false);
 
-	if (req->ff)
-		fuse_file_put(req->ff, false, false);
+	kfree(ap->pages);
+	kfree(wpa);
 }
 
-static void fuse_writepage_finish(struct fuse_conn *fc, struct fuse_req *req)
+static void fuse_writepage_finish(struct fuse_conn *fc,
+				  struct fuse_writepage_args *wpa)
 {
-	struct inode *inode = req->inode;
+	struct fuse_args_pages *ap = &wpa->ia.ap;
+	struct inode *inode = wpa->inode;
 	struct fuse_inode *fi = get_fuse_inode(inode);
 	struct backing_dev_info *bdi = inode_to_bdi(inode);
 	int i;
 
-	list_del(&req->writepages_entry);
-	for (i = 0; i < req->num_pages; i++) {
+	list_del(&wpa->writepages_entry);
+	for (i = 0; i < ap->num_pages; i++) {
 		dec_wb_stat(&bdi->wb, WB_WRITEBACK);
-		dec_node_page_state(req->pages[i], NR_WRITEBACK_TEMP);
+		dec_node_page_state(ap->pages[i], NR_WRITEBACK_TEMP);
 		wb_writeout_inc(&bdi->wb);
 	}
 	wake_up(&fi->page_waitq);
 }
 
 /* Called under fi->lock, may release and reacquire it */
-static void fuse_send_writepage(struct fuse_conn *fc, struct fuse_req *req,
-				loff_t size)
+static void fuse_send_writepage(struct fuse_conn *fc,
+				struct fuse_writepage_args *wpa, loff_t size)
 __releases(fi->lock)
 __acquires(fi->lock)
 {
-	struct fuse_req *aux, *next;
-	struct fuse_inode *fi = get_fuse_inode(req->inode);
-	struct fuse_write_in *inarg = &req->misc.write.in;
-	__u64 data_size = req->num_pages * PAGE_SIZE;
-	bool queued;
+	struct fuse_writepage_args *aux, *next;
+	struct fuse_inode *fi = get_fuse_inode(wpa->inode);
+	struct fuse_write_in *inarg = &wpa->ia.write.in;
+	struct fuse_args *args = &wpa->ia.ap.args;
+	__u64 data_size = wpa->ia.ap.num_pages * PAGE_SIZE;
+	int err;
 
+	fi->writectr++;
 	if (inarg->offset + data_size <= size) {
 		inarg->size = data_size;
 	} else if (inarg->offset < size) {
@@ -1557,29 +1621,36 @@ __acquires(fi->lock)
 		goto out_free;
 	}
 
-	req->in.args[1].size = inarg->size;
-	queued = fuse_request_queue_background(fc, req);
+	args->in_args[1].size = inarg->size;
+	args->force = true;
+	args->nocreds = true;
+
+	err = fuse_simple_background(fc, args, GFP_ATOMIC);
+	if (err == -ENOMEM) {
+		spin_unlock(&fi->lock);
+		err = fuse_simple_background(fc, args, GFP_NOFS | __GFP_NOFAIL);
+		spin_lock(&fi->lock);
+	}
+
 	/* Fails on broken connection only */
-	if (unlikely(!queued))
+	if (unlikely(err))
 		goto out_free;
 
-	fi->writectr++;
 	return;
 
  out_free:
-	fuse_writepage_finish(fc, req);
+	fi->writectr--;
+	fuse_writepage_finish(fc, wpa);
 	spin_unlock(&fi->lock);
 
 	/* After fuse_writepage_finish() aux request list is private */
-	for (aux = req->misc.write.next; aux; aux = next) {
-		next = aux->misc.write.next;
-		aux->misc.write.next = NULL;
-		fuse_writepage_free(fc, aux);
-		fuse_put_request(fc, aux);
+	for (aux = wpa->next; aux; aux = next) {
+		next = aux->next;
+		aux->next = NULL;
+		fuse_writepage_free(aux);
 	}
 
-	fuse_writepage_free(fc, req);
-	fuse_put_request(fc, req);
+	fuse_writepage_free(wpa);
 	spin_lock(&fi->lock);
 }
 
@@ -1596,29 +1667,34 @@ __acquires(fi->lock)
 	struct fuse_conn *fc = get_fuse_conn(inode);
 	struct fuse_inode *fi = get_fuse_inode(inode);
 	loff_t crop = i_size_read(inode);
-	struct fuse_req *req;
+	struct fuse_writepage_args *wpa;
 
 	while (fi->writectr >= 0 && !list_empty(&fi->queued_writes)) {
-		req = list_entry(fi->queued_writes.next, struct fuse_req, list);
-		list_del_init(&req->list);
-		fuse_send_writepage(fc, req, crop);
+		wpa = list_entry(fi->queued_writes.next,
+				 struct fuse_writepage_args, queue_entry);
+		list_del_init(&wpa->queue_entry);
+		fuse_send_writepage(fc, wpa, crop);
 	}
 }
 
-static void fuse_writepage_end(struct fuse_conn *fc, struct fuse_req *req)
+static void fuse_writepage_end(struct fuse_conn *fc, struct fuse_args *args,
+			       int error)
 {
-	struct inode *inode = req->inode;
+	struct fuse_writepage_args *wpa =
+		container_of(args, typeof(*wpa), ia.ap.args);
+	struct inode *inode = wpa->inode;
 	struct fuse_inode *fi = get_fuse_inode(inode);
 
-	mapping_set_error(inode->i_mapping, req->out.h.error);
+	mapping_set_error(inode->i_mapping, error);
 	spin_lock(&fi->lock);
-	while (req->misc.write.next) {
+	while (wpa->next) {
 		struct fuse_conn *fc = get_fuse_conn(inode);
-		struct fuse_write_in *inarg = &req->misc.write.in;
-		struct fuse_req *next = req->misc.write.next;
-		req->misc.write.next = next->misc.write.next;
-		next->misc.write.next = NULL;
-		next->ff = fuse_file_get(req->ff);
+		struct fuse_write_in *inarg = &wpa->ia.write.in;
+		struct fuse_writepage_args *next = wpa->next;
+
+		wpa->next = next->next;
+		next->next = NULL;
+		next->ia.ff = fuse_file_get(wpa->ia.ff);
 		list_add(&next->writepages_entry, &fi->writepages);
 
 		/*
@@ -1647,9 +1723,9 @@ static void fuse_writepage_end(struct fuse_conn *fc, struct fuse_req *req)
 		fuse_send_writepage(fc, next, inarg->offset + inarg->size);
 	}
 	fi->writectr--;
-	fuse_writepage_finish(fc, req);
+	fuse_writepage_finish(fc, wpa);
 	spin_unlock(&fi->lock);
-	fuse_writepage_free(fc, req);
+	fuse_writepage_free(wpa);
 }
 
 static struct fuse_file *__fuse_write_file_get(struct fuse_conn *fc,
@@ -1691,52 +1767,71 @@ int fuse_write_inode(struct inode *inode, struct writeback_control *wbc)
 	return err;
 }
 
+static struct fuse_writepage_args *fuse_writepage_args_alloc(void)
+{
+	struct fuse_writepage_args *wpa;
+	struct fuse_args_pages *ap;
+
+	wpa = kzalloc(sizeof(*wpa), GFP_NOFS);
+	if (wpa) {
+		ap = &wpa->ia.ap;
+		ap->num_pages = 0;
+		ap->pages = fuse_pages_alloc(1, GFP_NOFS, &ap->descs);
+		if (!ap->pages) {
+			kfree(wpa);
+			wpa = NULL;
+		}
+	}
+	return wpa;
+
+}
+
 static int fuse_writepage_locked(struct page *page)
 {
 	struct address_space *mapping = page->mapping;
 	struct inode *inode = mapping->host;
 	struct fuse_conn *fc = get_fuse_conn(inode);
 	struct fuse_inode *fi = get_fuse_inode(inode);
-	struct fuse_req *req;
+	struct fuse_writepage_args *wpa;
+	struct fuse_args_pages *ap;
 	struct page *tmp_page;
 	int error = -ENOMEM;
 
 	set_page_writeback(page);
 
-	req = fuse_request_alloc_nofs(1);
-	if (!req)
+	wpa = fuse_writepage_args_alloc();
+	if (!wpa)
 		goto err;
+	ap = &wpa->ia.ap;
 
-	/* writeback always goes to bg_queue */
-	__set_bit(FR_BACKGROUND, &req->flags);
 	tmp_page = alloc_page(GFP_NOFS | __GFP_HIGHMEM);
 	if (!tmp_page)
 		goto err_free;
 
 	error = -EIO;
-	req->ff = fuse_write_file_get(fc, fi);
-	if (!req->ff)
+	wpa->ia.ff = fuse_write_file_get(fc, fi);
+	if (!wpa->ia.ff)
 		goto err_nofile;
 
-	fuse_write_fill(req, req->ff, page_offset(page), 0);
+	fuse_write_args_fill(&wpa->ia, wpa->ia.ff, page_offset(page), 0);
 
 	copy_highpage(tmp_page, page);
-	req->misc.write.in.write_flags |= FUSE_WRITE_CACHE;
-	req->misc.write.next = NULL;
-	req->in.argpages = 1;
-	req->num_pages = 1;
-	req->pages[0] = tmp_page;
-	req->page_descs[0].offset = 0;
-	req->page_descs[0].length = PAGE_SIZE;
-	req->end = fuse_writepage_end;
-	req->inode = inode;
+	wpa->ia.write.in.write_flags |= FUSE_WRITE_CACHE;
+	wpa->next = NULL;
+	ap->args.in_pages = true;
+	ap->num_pages = 1;
+	ap->pages[0] = tmp_page;
+	ap->descs[0].offset = 0;
+	ap->descs[0].length = PAGE_SIZE;
+	ap->args.end = fuse_writepage_end;
+	wpa->inode = inode;
 
 	inc_wb_stat(&inode_to_bdi(inode)->wb, WB_WRITEBACK);
 	inc_node_page_state(tmp_page, NR_WRITEBACK_TEMP);
 
 	spin_lock(&fi->lock);
-	list_add(&req->writepages_entry, &fi->writepages);
-	list_add_tail(&req->list, &fi->queued_writes);
+	list_add(&wpa->writepages_entry, &fi->writepages);
+	list_add_tail(&wpa->queue_entry, &fi->queued_writes);
 	fuse_flush_writepages(inode);
 	spin_unlock(&fi->lock);
 
@@ -1747,7 +1842,7 @@ static int fuse_writepage_locked(struct page *page)
 err_nofile:
 	__free_page(tmp_page);
 err_free:
-	fuse_request_free(req);
+	kfree(wpa);
 err:
 	mapping_set_error(page->mapping, error);
 	end_page_writeback(page);
@@ -1767,6 +1862,7 @@ static int fuse_writepage(struct page *page, struct writeback_control *wbc)
 		WARN_ON(wbc->sync_mode == WB_SYNC_ALL);
 
 		redirty_page_for_writepage(wbc, page);
+		unlock_page(page);
 		return 0;
 	}
 
@@ -1777,23 +1873,50 @@ static int fuse_writepage(struct page *page, struct writeback_control *wbc)
 }
 
 struct fuse_fill_wb_data {
-	struct fuse_req *req;
+	struct fuse_writepage_args *wpa;
 	struct fuse_file *ff;
 	struct inode *inode;
 	struct page **orig_pages;
+	unsigned int max_pages;
 };
 
+static bool fuse_pages_realloc(struct fuse_fill_wb_data *data)
+{
+	struct fuse_args_pages *ap = &data->wpa->ia.ap;
+	struct fuse_conn *fc = get_fuse_conn(data->inode);
+	struct page **pages;
+	struct fuse_page_desc *descs;
+	unsigned int npages = min_t(unsigned int,
+				    max_t(unsigned int, data->max_pages * 2,
+					  FUSE_DEFAULT_MAX_PAGES_PER_REQ),
+				    fc->max_pages);
+	WARN_ON(npages <= data->max_pages);
+
+	pages = fuse_pages_alloc(npages, GFP_NOFS, &descs);
+	if (!pages)
+		return false;
+
+	memcpy(pages, ap->pages, sizeof(struct page *) * ap->num_pages);
+	memcpy(descs, ap->descs, sizeof(struct fuse_page_desc) * ap->num_pages);
+	kfree(ap->pages);
+	ap->pages = pages;
+	ap->descs = descs;
+	data->max_pages = npages;
+
+	return true;
+}
+
 static void fuse_writepages_send(struct fuse_fill_wb_data *data)
 {
-	struct fuse_req *req = data->req;
+	struct fuse_writepage_args *wpa = data->wpa;
 	struct inode *inode = data->inode;
 	struct fuse_inode *fi = get_fuse_inode(inode);
-	int num_pages = req->num_pages;
+	int num_pages = wpa->ia.ap.num_pages;
 	int i;
 
-	req->ff = fuse_file_get(data->ff);
+	wpa->ia.ff = fuse_file_get(data->ff);
 	spin_lock(&fi->lock);
-	list_add_tail(&req->list, &fi->queued_writes);
+	list_add_tail(&wpa->queue_entry, &fi->queued_writes);
 	fuse_flush_writepages(inode);
 	spin_unlock(&fi->lock);
 
@@ -1808,54 +1931,52 @@ static void fuse_writepages_send(struct fuse_fill_wb_data *data)
  * this new request onto the auxiliary list, otherwise reuse the existing one by
  * copying the new page contents over to the old temporary page.
  */
-static bool fuse_writepage_in_flight(struct fuse_req *new_req,
+static bool fuse_writepage_in_flight(struct fuse_writepage_args *new_wpa,
 				     struct page *page)
 {
-	struct fuse_conn *fc = get_fuse_conn(new_req->inode);
-	struct fuse_inode *fi = get_fuse_inode(new_req->inode);
-	struct fuse_req *tmp;
-	struct fuse_req *old_req;
+	struct fuse_inode *fi = get_fuse_inode(new_wpa->inode);
+	struct fuse_writepage_args *tmp;
+	struct fuse_writepage_args *old_wpa;
+	struct fuse_args_pages *new_ap = &new_wpa->ia.ap;
 
-	WARN_ON(new_req->num_pages != 0);
+	WARN_ON(new_ap->num_pages != 0);
 
 	spin_lock(&fi->lock);
-	list_del(&new_req->writepages_entry);
-	old_req = fuse_find_writeback(fi, page->index, page->index);
-	if (!old_req) {
-		list_add(&new_req->writepages_entry, &fi->writepages);
+	list_del(&new_wpa->writepages_entry);
+	old_wpa = fuse_find_writeback(fi, page->index, page->index);
+	if (!old_wpa) {
+		list_add(&new_wpa->writepages_entry, &fi->writepages);
 		spin_unlock(&fi->lock);
 		return false;
 	}
 
-	new_req->num_pages = 1;
-	for (tmp = old_req->misc.write.next; tmp; tmp = tmp->misc.write.next) {
+	new_ap->num_pages = 1;
+	for (tmp = old_wpa->next; tmp; tmp = tmp->next) {
 		pgoff_t curr_index;
 
-		WARN_ON(tmp->inode != new_req->inode);
-		curr_index = tmp->misc.write.in.offset >> PAGE_SHIFT;
+		WARN_ON(tmp->inode != new_wpa->inode);
+		curr_index = tmp->ia.write.in.offset >> PAGE_SHIFT;
 		if (curr_index == page->index) {
-			WARN_ON(tmp->num_pages != 1);
-			WARN_ON(!test_bit(FR_PENDING, &tmp->flags));
-			swap(tmp->pages[0], new_req->pages[0]);
+			WARN_ON(tmp->ia.ap.num_pages != 1);
+			swap(tmp->ia.ap.pages[0], new_ap->pages[0]);
 			break;
 		}
 	}
 
 	if (!tmp) {
-		new_req->misc.write.next = old_req->misc.write.next;
-		old_req->misc.write.next = new_req;
+		new_wpa->next = old_wpa->next;
+		old_wpa->next = new_wpa;
 	}
 
 	spin_unlock(&fi->lock);
 
 	if (tmp) {
-		struct backing_dev_info *bdi = inode_to_bdi(new_req->inode);
+		struct backing_dev_info *bdi = inode_to_bdi(new_wpa->inode);
 
 		dec_wb_stat(&bdi->wb, WB_WRITEBACK);
-		dec_node_page_state(new_req->pages[0], NR_WRITEBACK_TEMP);
+		dec_node_page_state(new_ap->pages[0], NR_WRITEBACK_TEMP);
 		wb_writeout_inc(&bdi->wb);
-		fuse_writepage_free(fc, new_req);
-		fuse_request_free(new_req);
+		fuse_writepage_free(new_wpa);
 	}
 
 	return true;
@@ -1865,7 +1986,8 @@ static int fuse_writepages_fill(struct page *page,
 		struct writeback_control *wbc, void *_data)
 {
 	struct fuse_fill_wb_data *data = _data;
-	struct fuse_req *req = data->req;
+	struct fuse_writepage_args *wpa = data->wpa;
+	struct fuse_args_pages *ap = &wpa->ia.ap;
 	struct inode *inode = data->inode;
 	struct fuse_inode *fi = get_fuse_inode(inode);
 	struct fuse_conn *fc = get_fuse_conn(inode);
@@ -1888,16 +2010,16 @@ static int fuse_writepages_fill(struct page *page,
 	 */
 	is_writeback = fuse_page_is_writeback(inode, page->index);
 
-	if (req && req->num_pages &&
-	    (is_writeback || req->num_pages == fc->max_pages ||
-	     (req->num_pages + 1) * PAGE_SIZE > fc->max_write ||
-	     data->orig_pages[req->num_pages - 1]->index + 1 != page->index)) {
+	if (wpa && ap->num_pages &&
+	    (is_writeback || ap->num_pages == fc->max_pages ||
+	     (ap->num_pages + 1) * PAGE_SIZE > fc->max_write ||
+	     data->orig_pages[ap->num_pages - 1]->index + 1 != page->index)) {
 		fuse_writepages_send(data);
-		data->req = NULL;
-	} else if (req && req->num_pages == req->max_pages) {
-		if (!fuse_req_realloc_pages(fc, req, GFP_NOFS)) {
+		data->wpa = NULL;
+	} else if (wpa && ap->num_pages == data->max_pages) {
+		if (!fuse_pages_realloc(data)) {
 			fuse_writepages_send(data);
-			req = data->req = NULL;
+			data->wpa = NULL;
 		}
 	}
 
@@ -1915,59 +2037,60 @@ static int fuse_writepages_fill(struct page *page,
 	 * This is ensured by holding the page lock in page_mkwrite() while
 	 * checking fuse_page_is_writeback().  We already hold the page lock
 	 * since clear_page_dirty_for_io() and keep it held until we add the
-	 * request to the fi->writepages list and increment req->num_pages.
+	 * request to the fi->writepages list and increment ap->num_pages.
 	 * After this fuse_page_is_writeback() will indicate that the page is
 	 * under writeback, so we can release the page lock.
 	 */
-	if (data->req == NULL) {
+	if (data->wpa == NULL) {
 		struct fuse_inode *fi = get_fuse_inode(inode);
 
 		err = -ENOMEM;
-		req = fuse_request_alloc_nofs(FUSE_REQ_INLINE_PAGES);
-		if (!req) {
+		wpa = fuse_writepage_args_alloc();
+		if (!wpa) {
 			__free_page(tmp_page);
 			goto out_unlock;
 		}
+		data->max_pages = 1;
 
-		fuse_write_fill(req, data->ff, page_offset(page), 0);
-		req->misc.write.in.write_flags |= FUSE_WRITE_CACHE;
-		req->misc.write.next = NULL;
-		req->in.argpages = 1;
-		__set_bit(FR_BACKGROUND, &req->flags);
-		req->num_pages = 0;
-		req->end = fuse_writepage_end;
-		req->inode = inode;
+		ap = &wpa->ia.ap;
+		fuse_write_args_fill(&wpa->ia, data->ff, page_offset(page), 0);
+		wpa->ia.write.in.write_flags |= FUSE_WRITE_CACHE;
+		wpa->next = NULL;
+		ap->args.in_pages = true;
+		ap->args.end = fuse_writepage_end;
+		ap->num_pages = 0;
+		wpa->inode = inode;
 
 		spin_lock(&fi->lock);
-		list_add(&req->writepages_entry, &fi->writepages);
+		list_add(&wpa->writepages_entry, &fi->writepages);
 		spin_unlock(&fi->lock);
 
-		data->req = req;
+		data->wpa = wpa;
 	}
 	set_page_writeback(page);
 
 	copy_highpage(tmp_page, page);
-	req->pages[req->num_pages] = tmp_page;
-	req->page_descs[req->num_pages].offset = 0;
-	req->page_descs[req->num_pages].length = PAGE_SIZE;
+	ap->pages[ap->num_pages] = tmp_page;
+	ap->descs[ap->num_pages].offset = 0;
+	ap->descs[ap->num_pages].length = PAGE_SIZE;
 
 	inc_wb_stat(&inode_to_bdi(inode)->wb, WB_WRITEBACK);
 	inc_node_page_state(tmp_page, NR_WRITEBACK_TEMP);
 
 	err = 0;
-	if (is_writeback && fuse_writepage_in_flight(req, page)) {
+	if (is_writeback && fuse_writepage_in_flight(wpa, page)) {
 		end_page_writeback(page);
-		data->req = NULL;
+		data->wpa = NULL;
 		goto out_unlock;
 	}
-	data->orig_pages[req->num_pages] = page;
+	data->orig_pages[ap->num_pages] = page;
 
 	/*
 	 * Protected by fi->lock against concurrent access by
 	 * fuse_page_is_writeback().
 	 */
 	spin_lock(&fi->lock);
-	req->num_pages++;
+	ap->num_pages++;
 	spin_unlock(&fi->lock);
 
 out_unlock:
@@ -1989,7 +2112,7 @@ static int fuse_writepages(struct address_space *mapping,
 		goto out;
 
 	data.inode = inode;
-	data.req = NULL;
+	data.wpa = NULL;
 	data.ff = NULL;
 
 	err = -ENOMEM;
@@ -2000,9 +2123,9 @@ static int fuse_writepages(struct address_space *mapping,
 		goto out;
 
 	err = write_cache_pages(mapping, wbc, fuse_writepages_fill, &data);
-	if (data.req) {
+	if (data.wpa) {
 		/* Ignore errors if we can write at least one page */
-		BUG_ON(!data.req->num_pages);
+		WARN_ON(!data.wpa->ia.ap.num_pages);
 		fuse_writepages_send(&data);
 		err = 0;
 	}
@@ -2222,11 +2345,11 @@ static void fuse_lk_fill(struct fuse_args *args, struct file *file,
 	inarg->lk.pid = pid;
 	if (flock)
 		inarg->lk_flags |= FUSE_LK_FLOCK;
-	args->in.h.opcode = opcode;
-	args->in.h.nodeid = get_node_id(inode);
-	args->in.numargs = 1;
-	args->in.args[0].size = sizeof(*inarg);
-	args->in.args[0].value = inarg;
+	args->opcode = opcode;
+	args->nodeid = get_node_id(inode);
+	args->in_numargs = 1;
+	args->in_args[0].size = sizeof(*inarg);
+	args->in_args[0].value = inarg;
 }
 
 static int fuse_getlk(struct file *file, struct file_lock *fl)
@@ -2239,9 +2362,9 @@ static int fuse_getlk(struct file *file, struct file_lock *fl)
 	int err;
 
 	fuse_lk_fill(&args, file, fl, FUSE_GETLK, 0, 0, &inarg);
-	args.out.numargs = 1;
-	args.out.args[0].size = sizeof(outarg);
-	args.out.args[0].value = &outarg;
+	args.out_numargs = 1;
+	args.out_args[0].size = sizeof(outarg);
+	args.out_args[0].value = &outarg;
 	err = fuse_simple_request(fc, &args);
 	if (!err)
 		err = convert_fuse_file_lock(fc, &outarg.lk, fl);
@@ -2336,14 +2459,14 @@ static sector_t fuse_bmap(struct address_space *mapping, sector_t block)
 	memset(&inarg, 0, sizeof(inarg));
 	inarg.block = block;
 	inarg.blocksize = inode->i_sb->s_blocksize;
-	args.in.h.opcode = FUSE_BMAP;
-	args.in.h.nodeid = get_node_id(inode);
-	args.in.numargs = 1;
-	args.in.args[0].size = sizeof(inarg);
-	args.in.args[0].value = &inarg;
-	args.out.numargs = 1;
-	args.out.args[0].size = sizeof(outarg);
-	args.out.args[0].value = &outarg;
+	args.opcode = FUSE_BMAP;
+	args.nodeid = get_node_id(inode);
+	args.in_numargs = 1;
+	args.in_args[0].size = sizeof(inarg);
+	args.in_args[0].value = &inarg;
+	args.out_numargs = 1;
+	args.out_args[0].size = sizeof(outarg);
+	args.out_args[0].value = &outarg;
 	err = fuse_simple_request(fc, &args);
 	if (err == -ENOSYS)
 		fc->no_bmap = 1;
@@ -2368,14 +2491,14 @@ static loff_t fuse_lseek(struct file *file, loff_t offset, int whence)
 	if (fc->no_lseek)
 		goto fallback;
 
-	args.in.h.opcode = FUSE_LSEEK;
-	args.in.h.nodeid = ff->nodeid;
-	args.in.numargs = 1;
-	args.in.args[0].size = sizeof(inarg);
-	args.in.args[0].value = &inarg;
-	args.out.numargs = 1;
-	args.out.args[0].size = sizeof(outarg);
-	args.out.args[0].value = &outarg;
+	args.opcode = FUSE_LSEEK;
+	args.nodeid = ff->nodeid;
+	args.in_numargs = 1;
+	args.in_args[0].size = sizeof(inarg);
+	args.in_args[0].value = &inarg;
+	args.out_numargs = 1;
+	args.out_args[0].size = sizeof(outarg);
+	args.out_args[0].value = &outarg;
 	err = fuse_simple_request(fc, &args);
 	if (err) {
 		if (err == -ENOSYS) {
@@ -2573,14 +2696,14 @@ long fuse_do_ioctl(struct file *file, unsigned int cmd, unsigned long arg,
 		.flags = flags
 	};
 	struct fuse_ioctl_out outarg;
-	struct fuse_req *req = NULL;
-	struct page **pages = NULL;
 	struct iovec *iov_page = NULL;
 	struct iovec *in_iov = NULL, *out_iov = NULL;
-	unsigned int in_iovs = 0, out_iovs = 0, num_pages = 0, max_pages;
-	size_t in_size, out_size, transferred, c;
+	unsigned int in_iovs = 0, out_iovs = 0, max_pages;
+	size_t in_size, out_size, c;
+	ssize_t transferred;
 	int err, i;
 	struct iov_iter ii;
+	struct fuse_args_pages ap = {};
 
 #if BITS_PER_LONG == 32
 	inarg.flags |= FUSE_IOCTL_32BIT;
@@ -2598,11 +2721,13 @@ long fuse_do_ioctl(struct file *file, unsigned int cmd, unsigned long arg,
 	BUILD_BUG_ON(sizeof(struct fuse_ioctl_iovec) * FUSE_IOCTL_MAX_IOV > PAGE_SIZE);
 
 	err = -ENOMEM;
-	pages = kcalloc(fc->max_pages, sizeof(pages[0]), GFP_KERNEL);
+	ap.pages = fuse_pages_alloc(fc->max_pages, GFP_KERNEL, &ap.descs);
 	iov_page = (struct iovec *) __get_free_page(GFP_KERNEL);
-	if (!pages || !iov_page)
+	if (!ap.pages || !iov_page)
 		goto out;
 
+	fuse_page_descs_length_init(ap.descs, 0, fc->max_pages);
+
 	/*
 	 * If restricted, initialize IO parameters as encoded in @cmd.
 	 * RETRY from server is not allowed.
@@ -2639,56 +2764,44 @@ long fuse_do_ioctl(struct file *file, unsigned int cmd, unsigned long arg,
 	err = -ENOMEM;
 	if (max_pages > fc->max_pages)
 		goto out;
-	while (num_pages < max_pages) {
-		pages[num_pages] = alloc_page(GFP_KERNEL | __GFP_HIGHMEM);
-		if (!pages[num_pages])
+	while (ap.num_pages < max_pages) {
+		ap.pages[ap.num_pages] = alloc_page(GFP_KERNEL | __GFP_HIGHMEM);
+		if (!ap.pages[ap.num_pages])
 			goto out;
-		num_pages++;
+		ap.num_pages++;
 	}
 
-	req = fuse_get_req(fc, num_pages);
-	if (IS_ERR(req)) {
-		err = PTR_ERR(req);
-		req = NULL;
-		goto out;
-	}
-	memcpy(req->pages, pages, sizeof(req->pages[0]) * num_pages);
-	req->num_pages = num_pages;
-	fuse_page_descs_length_init(req, 0, req->num_pages);
 
 	/* okay, let's send it to the client */
-	req->in.h.opcode = FUSE_IOCTL;
-	req->in.h.nodeid = ff->nodeid;
-	req->in.numargs = 1;
-	req->in.args[0].size = sizeof(inarg);
-	req->in.args[0].value = &inarg;
+	ap.args.opcode = FUSE_IOCTL;
+	ap.args.nodeid = ff->nodeid;
+	ap.args.in_numargs = 1;
+	ap.args.in_args[0].size = sizeof(inarg);
+	ap.args.in_args[0].value = &inarg;
 	if (in_size) {
-		req->in.numargs++;
-		req->in.args[1].size = in_size;
-		req->in.argpages = 1;
+		ap.args.in_numargs++;
+		ap.args.in_args[1].size = in_size;
+		ap.args.in_pages = true;
 
 		err = -EFAULT;
 		iov_iter_init(&ii, WRITE, in_iov, in_iovs, in_size);
-		for (i = 0; iov_iter_count(&ii) && !WARN_ON(i >= num_pages); i++) {
-			c = copy_page_from_iter(pages[i], 0, PAGE_SIZE, &ii);
+		for (i = 0; iov_iter_count(&ii) && !WARN_ON(i >= ap.num_pages); i++) {
+			c = copy_page_from_iter(ap.pages[i], 0, PAGE_SIZE, &ii);
 			if (c != PAGE_SIZE && iov_iter_count(&ii))
 				goto out;
 		}
 	}
 
-	req->out.numargs = 2;
-	req->out.args[0].size = sizeof(outarg);
-	req->out.args[0].value = &outarg;
-	req->out.args[1].size = out_size;
-	req->out.argpages = 1;
-	req->out.argvar = 1;
+	ap.args.out_numargs = 2;
+	ap.args.out_args[0].size = sizeof(outarg);
+	ap.args.out_args[0].value = &outarg;
+	ap.args.out_args[1].size = out_size;
+	ap.args.out_pages = true;
+	ap.args.out_argvar = true;
 
-	fuse_request_send(fc, req);
-	err = req->out.h.error;
-	transferred = req->out.args[1].size;
-	fuse_put_request(fc, req);
-	req = NULL;
-	if (err)
+	transferred = fuse_simple_request(fc, &ap.args);
+	err = transferred;
+	if (transferred < 0)
 		goto out;
 
 	/* did it ask for retry? */
@@ -2713,7 +2826,7 @@ long fuse_do_ioctl(struct file *file, unsigned int cmd, unsigned long arg,
 		    in_iovs + out_iovs > FUSE_IOCTL_MAX_IOV)
 			goto out;
 
-		vaddr = kmap_atomic(pages[0]);
+		vaddr = kmap_atomic(ap.pages[0]);
 		err = fuse_copy_ioctl_iovec(fc, iov_page, vaddr,
 					    transferred, in_iovs + out_iovs,
 					    (flags & FUSE_IOCTL_COMPAT) != 0);
@@ -2741,19 +2854,17 @@ long fuse_do_ioctl(struct file *file, unsigned int cmd, unsigned long arg,
 
 	err = -EFAULT;
 	iov_iter_init(&ii, READ, out_iov, out_iovs, transferred);
-	for (i = 0; iov_iter_count(&ii) && !WARN_ON(i >= num_pages); i++) {
-		c = copy_page_to_iter(pages[i], 0, PAGE_SIZE, &ii);
+	for (i = 0; iov_iter_count(&ii) && !WARN_ON(i >= ap.num_pages); i++) {
+		c = copy_page_to_iter(ap.pages[i], 0, PAGE_SIZE, &ii);
 		if (c != PAGE_SIZE && iov_iter_count(&ii))
 			goto out;
 	}
 	err = 0;
  out:
-	if (req)
-		fuse_put_request(fc, req);
 	free_page((unsigned long) iov_page);
-	while (num_pages)
-		__free_page(pages[--num_pages]);
-	kfree(pages);
+	while (ap.num_pages)
+		__free_page(ap.pages[--ap.num_pages]);
+	kfree(ap.pages);
 
 	return err ? err : outarg.result;
 }
@@ -2861,14 +2972,14 @@ __poll_t fuse_file_poll(struct file *file, poll_table *wait)
 		fuse_register_polled_file(fc, ff);
 	}
 
-	args.in.h.opcode = FUSE_POLL;
-	args.in.h.nodeid = ff->nodeid;
-	args.in.numargs = 1;
-	args.in.args[0].size = sizeof(inarg);
-	args.in.args[0].value = &inarg;
-	args.out.numargs = 1;
-	args.out.args[0].size = sizeof(outarg);
-	args.out.args[0].value = &outarg;
+	args.opcode = FUSE_POLL;
+	args.nodeid = ff->nodeid;
+	args.in_numargs = 1;
+	args.in_args[0].size = sizeof(inarg);
+	args.in_args[0].value = &inarg;
+	args.out_numargs = 1;
+	args.out_args[0].size = sizeof(outarg);
+	args.out_args[0].value = &outarg;
 	err = fuse_simple_request(fc, &args);
 
 	if (!err)
@@ -3076,11 +3187,11 @@ static long fuse_file_fallocate(struct file *file, int mode, loff_t offset,
 	if (!(mode & FALLOC_FL_KEEP_SIZE))
 		set_bit(FUSE_I_SIZE_UNSTABLE, &fi->state);
 
-	args.in.h.opcode = FUSE_FALLOCATE;
-	args.in.h.nodeid = ff->nodeid;
-	args.in.numargs = 1;
-	args.in.args[0].size = sizeof(inarg);
-	args.in.args[0].value = &inarg;
+	args.opcode = FUSE_FALLOCATE;
+	args.nodeid = ff->nodeid;
+	args.in_numargs = 1;
+	args.in_args[0].size = sizeof(inarg);
+	args.in_args[0].value = &inarg;
 	err = fuse_simple_request(fc, &args);
 	if (err == -ENOSYS) {
 		fc->no_fallocate = 1;
@@ -3168,14 +3279,14 @@ static ssize_t __fuse_copy_file_range(struct file *file_in, loff_t pos_in,
 	if (is_unstable)
 		set_bit(FUSE_I_SIZE_UNSTABLE, &fi_out->state);
 
-	args.in.h.opcode = FUSE_COPY_FILE_RANGE;
-	args.in.h.nodeid = ff_in->nodeid;
-	args.in.numargs = 1;
-	args.in.args[0].size = sizeof(inarg);
-	args.in.args[0].value = &inarg;
-	args.out.numargs = 1;
-	args.out.args[0].size = sizeof(outarg);
-	args.out.args[0].value = &outarg;
+	args.opcode = FUSE_COPY_FILE_RANGE;
+	args.nodeid = ff_in->nodeid;
+	args.in_numargs = 1;
+	args.in_args[0].size = sizeof(inarg);
+	args.in_args[0].value = &inarg;
+	args.out_numargs = 1;
+	args.out_args[0].size = sizeof(outarg);
+	args.out_args[0].value = &outarg;
 	err = fuse_simple_request(fc, &args);
 	if (err == -ENOSYS) {
 		fc->no_copy_file_range = 1;

fs/fuse/fuse_i.h

@@ -47,9 +47,6 @@
 /** Number of dentries for each connection in the control filesystem */
 #define FUSE_CTL_NUM_DENTRIES 5
 
-/** Number of page pointers embedded in fuse_req */
-#define FUSE_REQ_INLINE_PAGES 1
-
 /** List of active connections */
 extern struct list_head fuse_conn_list;
 
@@ -164,17 +161,15 @@ enum {
 };
 
 struct fuse_conn;
+struct fuse_release_args;
 
 /** FUSE specific file data */
 struct fuse_file {
 	/** Fuse connection for this file */
 	struct fuse_conn *fc;
 
-	/*
-	 * Request reserved for flush and release.
-	 * Modified under relative fuse_inode::lock.
-	 */
-	struct fuse_req *reserved_req;
+	/* Argument space reserved for release */
+	struct fuse_release_args *release_args;
 
 	/** Kernel file handle guaranteed to be unique */
 	u64 kh;
@@ -229,57 +224,12 @@ struct fuse_in_arg {
 	const void *value;
 };
 
-/** The request input */
-struct fuse_in {
-	/** The request header */
-	struct fuse_in_header h;
-
-	/** True if the data for the last argument is in req->pages */
-	unsigned argpages:1;
-
-	/** Number of arguments */
-	unsigned numargs;
-
-	/** Array of arguments */
-	struct fuse_in_arg args[3];
-};
-
 /** One output argument of a request */
 struct fuse_arg {
 	unsigned size;
 	void *value;
 };
 
-/** The request output */
-struct fuse_out {
-	/** Header returned from userspace */
-	struct fuse_out_header h;
-
-	/*
-	 * The following bitfields are not changed during the request
-	 * processing
-	 */
-
-	/** Last argument is variable length (can be shorter than
-	    arg->size) */
-	unsigned argvar:1;
-
-	/** Last argument is a list of pages to copy data to */
-	unsigned argpages:1;
-
-	/** Zero partially or not copied pages */
-	unsigned page_zeroing:1;
-
-	/** Pages may be replaced with new ones */
-	unsigned page_replace:1;
-
-	/** Number or arguments */
-	unsigned numargs;
-
-	/** Array of arguments */
-	struct fuse_arg args[2];
-};
-
 /** FUSE page descriptor */
 struct fuse_page_desc {
 	unsigned int length;
@@ -287,20 +237,28 @@ struct fuse_page_desc {
 };
 
 struct fuse_args {
-	struct {
-		struct {
-			uint32_t opcode;
-			uint64_t nodeid;
-		} h;
-		unsigned numargs;
-		struct fuse_in_arg args[3];
+	uint64_t nodeid;
+	uint32_t opcode;
+	unsigned short in_numargs;
+	unsigned short out_numargs;
+	bool force:1;
+	bool noreply:1;
+	bool nocreds:1;
+	bool in_pages:1;
+	bool out_pages:1;
+	bool out_argvar:1;
+	bool page_zeroing:1;
+	bool page_replace:1;
+	struct fuse_in_arg in_args[3];
+	struct fuse_arg out_args[2];
+	void (*end)(struct fuse_conn *fc, struct fuse_args *args, int error);
+};
 
-	} in;
-	struct {
-		unsigned argvar:1;
-		unsigned numargs;
-		struct fuse_arg args[2];
-	} out;
+struct fuse_args_pages {
+	struct fuse_args args;
+	struct page **pages;
+	struct fuse_page_desc *descs;
+	unsigned int num_pages;
 };
 
 #define FUSE_ARGS(args) struct fuse_args args = {}
@@ -373,83 +331,70 @@ struct fuse_req {
 	/** Entry on the interrupts list  */
 	struct list_head intr_entry;
 
+	/* Input/output arguments */
+	struct fuse_args *args;
+
 	/** refcount */
 	refcount_t count;
 
 	/* Request flags, updated with test/set/clear_bit() */
 	unsigned long flags;
 
-	/** The request input */
-	struct fuse_in in;
+	/* The request input header */
+	struct {
+		struct fuse_in_header h;
+	} in;
 
-	/** The request output */
-	struct fuse_out out;
+	/* The request output header */
+	struct {
+		struct fuse_out_header h;
+	} out;
 
 	/** Used to wake up the task waiting for completion of request*/
 	wait_queue_head_t waitq;
 
-	/** Data for asynchronous requests */
-	union {
-		struct {
-			struct fuse_release_in in;
-			struct inode *inode;
-		} release;
-		struct fuse_init_in init_in;
-		struct fuse_init_out init_out;
-		struct cuse_init_in cuse_init_in;
-		struct {
-			struct fuse_read_in in;
-			u64 attr_ver;
-		} read;
-		struct {
-			struct fuse_write_in in;
-			struct fuse_write_out out;
-			struct fuse_req *next;
-		} write;
-		struct fuse_notify_retrieve_in retrieve_in;
-	} misc;
-
-	/** page vector */
-	struct page **pages;
-
-	/** page-descriptor vector */
-	struct fuse_page_desc *page_descs;
-
-	/** size of the 'pages' array */
-	unsigned max_pages;
-
-	/** inline page vector */
-	struct page *inline_pages[FUSE_REQ_INLINE_PAGES];
-
-	/** inline page-descriptor vector */
-	struct fuse_page_desc inline_page_descs[FUSE_REQ_INLINE_PAGES];
-
-	/** number of pages in vector */
-	unsigned num_pages;
-
-	/** File used in the request (or NULL) */
-	struct fuse_file *ff;
-
-	/** Inode used in the request or NULL */
-	struct inode *inode;
+};
 
-	/** AIO control block */
-	struct fuse_io_priv *io;
+struct fuse_iqueue;
 
-	/** Link on fi->writepages */
-	struct list_head writepages_entry;
+/**
+ * Input queue callbacks
+ *
+ * Input queue signalling is device-specific.  For example, the /dev/fuse file
+ * uses fiq->waitq and fasync to wake processes that are waiting on queue
+ * readiness.  These callbacks allow other device types to respond to input
+ * queue activity.
+ */
+struct fuse_iqueue_ops {
+	/**
+	 * Signal that a forget has been queued
+	 */
+	void (*wake_forget_and_unlock)(struct fuse_iqueue *fiq)
+		__releases(fiq->lock);
 
-	/** Request completion callback */
-	void (*end)(struct fuse_conn *, struct fuse_req *);
+	/**
+	 * Signal that an INTERRUPT request has been queued
+	 */
+	void (*wake_interrupt_and_unlock)(struct fuse_iqueue *fiq)
+		__releases(fiq->lock);
 
-	/** Request is stolen from fuse_file->reserved_req */
-	struct file *stolen_file;
+	/**
+	 * Signal that a request has been queued
+	 */
+	void (*wake_pending_and_unlock)(struct fuse_iqueue *fiq)
+		__releases(fiq->lock);
 };
 
+/** /dev/fuse input queue operations */
+extern const struct fuse_iqueue_ops fuse_dev_fiq_ops;
+
 struct fuse_iqueue {
 	/** Connection established */
 	unsigned connected;
 
+	/** Lock protecting accesses to members of this structure */
+	spinlock_t lock;
+
 	/** Readers of the connection are waiting on this */
 	wait_queue_head_t waitq;
 
@@ -471,6 +416,12 @@ struct fuse_iqueue {
 
 	/** O_ASYNC requests */
 	struct fasync_struct *fasync;
+
+	/** Device-specific callbacks */
+	const struct fuse_iqueue_ops *ops;
+
+	/** Device-specific state */
+	void *priv;
 };
 
 #define FUSE_PQ_HASH_BITS 8
@@ -504,6 +455,29 @@ struct fuse_dev {
 	struct list_head entry;
 };
 
+struct fuse_fs_context {
+	int fd;
+	unsigned int rootmode;
+	kuid_t user_id;
+	kgid_t group_id;
+	bool is_bdev:1;
+	bool fd_present:1;
+	bool rootmode_present:1;
+	bool user_id_present:1;
+	bool group_id_present:1;
+	bool default_permissions:1;
+	bool allow_other:1;
+	bool destroy:1;
+	bool no_control:1;
+	bool no_force_umount:1;
+	unsigned int max_read;
+	unsigned int blksize;
+	const char *subtype;
+
+	/* fuse_dev pointer to fill in, should contain NULL on entry */
+	void **fudptr;
+};
+
 /**
  * A Fuse connection.
  *
@@ -584,9 +558,6 @@ struct fuse_conn {
 	/** waitq for blocked connection */
 	wait_queue_head_t blocked_waitq;
 
-	/** waitq for reserved requests */
-	wait_queue_head_t reserved_req_waitq;
-
 	/** Connection established, cleared on umount, connection
 	    abort and device release */
 	unsigned connected;
@@ -721,6 +692,18 @@ struct fuse_conn {
 	/** Does the filesystem support copy_file_range? */
 	unsigned no_copy_file_range:1;
 
+	/* Send DESTROY request */
+	unsigned int destroy:1;
+
+	/* Delete dentries that have gone stale */
+	unsigned int delete_stale:1;
+
+	/** Do not create entry in fusectl fs */
+	unsigned int no_control:1;
+
+	/** Do not allow MNT_FORCE umount */
+	unsigned int no_force_umount:1;
+
 	/** The number of requests waiting for completion */
 	atomic_t num_waiting;
 
@@ -742,9 +725,6 @@ struct fuse_conn {
 	/** Key for lock owner ID scrambling */
 	u32 scramble_key[4];
 
-	/** Reserved request for the DESTROY message */
-	struct fuse_req *destroy_req;
-
 	/** Version counter for attribute changes */
 	atomic64_t attr_version;
 
@@ -820,14 +800,32 @@ void fuse_queue_forget(struct fuse_conn *fc, struct fuse_forget_link *forget,
 
 struct fuse_forget_link *fuse_alloc_forget(void);
 
-/* Used by READDIRPLUS */
-void fuse_force_forget(struct file *file, u64 nodeid);
+struct fuse_forget_link *fuse_dequeue_forget(struct fuse_iqueue *fiq,
+					     unsigned int max,
+					     unsigned int *countp);
 
-/**
+/*
  * Initialize READ or READDIR request
  */
-void fuse_read_fill(struct fuse_req *req, struct file *file,
-		    loff_t pos, size_t count, int opcode);
+struct fuse_io_args {
+	union {
+		struct {
+			struct fuse_read_in in;
+			u64 attr_ver;
+		} read;
+		struct {
+			struct fuse_write_in in;
+			struct fuse_write_out out;
+		} write;
+	};
+	struct fuse_args_pages ap;
+	struct fuse_io_priv *io;
+	struct fuse_file *ff;
+};
+
+void fuse_read_args_fill(struct fuse_io_args *ia, struct file *file, loff_t pos,
+			 size_t count, int opcode);
+
 
 /**
  * Send OPEN or OPENDIR request
@@ -899,62 +897,17 @@ void fuse_dev_cleanup(void);
 int fuse_ctl_init(void);
 void __exit fuse_ctl_cleanup(void);
 
-/**
- * Allocate a request
- */
-struct fuse_req *fuse_request_alloc(unsigned npages);
-
-struct fuse_req *fuse_request_alloc_nofs(unsigned npages);
-
-bool fuse_req_realloc_pages(struct fuse_conn *fc, struct fuse_req *req,
-			    gfp_t flags);
-
-
-/**
- * Free a request
- */
-void fuse_request_free(struct fuse_req *req);
-
-/**
- * Get a request, may fail with -ENOMEM,
- * caller should specify # elements in req->pages[] explicitly
- */
-struct fuse_req *fuse_get_req(struct fuse_conn *fc, unsigned npages);
-struct fuse_req *fuse_get_req_for_background(struct fuse_conn *fc,
-					     unsigned npages);
-
-/*
- * Increment reference count on request
- */
-void __fuse_get_request(struct fuse_req *req);
-
-/**
- * Gets a requests for a file operation, always succeeds
- */
-struct fuse_req *fuse_get_req_nofail_nopages(struct fuse_conn *fc,
-					     struct file *file);
-
-/**
- * Decrement reference count of a request.  If count goes to zero free
- * the request.
- */
-void fuse_put_request(struct fuse_conn *fc, struct fuse_req *req);
-
-/**
- * Send a request (synchronous)
- */
-void fuse_request_send(struct fuse_conn *fc, struct fuse_req *req);
-
 /**
  * Simple request sending that does request allocation and freeing
  */
 ssize_t fuse_simple_request(struct fuse_conn *fc, struct fuse_args *args);
+int fuse_simple_background(struct fuse_conn *fc, struct fuse_args *args,
+			   gfp_t gfp_flags);
 
 /**
- * Send a request in the background
+ * End a finished request
  */
-void fuse_request_send_background(struct fuse_conn *fc, struct fuse_req *req);
-bool fuse_request_queue_background(struct fuse_conn *fc, struct fuse_req *req);
+void fuse_request_end(struct fuse_conn *fc, struct fuse_req *req);
 
 /* Abort all requests */
 void fuse_abort_conn(struct fuse_conn *fc);
@@ -980,15 +933,33 @@ struct fuse_conn *fuse_conn_get(struct fuse_conn *fc);
 /**
  * Initialize fuse_conn
  */
-void fuse_conn_init(struct fuse_conn *fc, struct user_namespace *user_ns);
+void fuse_conn_init(struct fuse_conn *fc, struct user_namespace *user_ns,
+		    const struct fuse_iqueue_ops *fiq_ops, void *fiq_priv);
 
 /**
  * Release reference to fuse_conn
  */
 void fuse_conn_put(struct fuse_conn *fc);
 
-struct fuse_dev *fuse_dev_alloc(struct fuse_conn *fc);
+struct fuse_dev *fuse_dev_alloc_install(struct fuse_conn *fc);
+struct fuse_dev *fuse_dev_alloc(void);
+void fuse_dev_install(struct fuse_dev *fud, struct fuse_conn *fc);
 void fuse_dev_free(struct fuse_dev *fud);
+void fuse_send_init(struct fuse_conn *fc);
+
+/**
+ * Fill in superblock and initialize fuse connection
+ * @sb: partially-initialized superblock to fill in
+ * @ctx: mount context
+ */
+int fuse_fill_super_common(struct super_block *sb, struct fuse_fs_context *ctx);
+
+/**
+ * Disassociate fuse connection from superblock and kill the superblock
+ *
+ * Calls kill_anon_super(), do not use with bdev mounts.
+ */
+void fuse_kill_sb_anon(struct super_block *sb);
 
 /**
  * Add connection to control filesystem
@@ -1093,4 +1064,15 @@ int fuse_set_acl(struct inode *inode, struct posix_acl *acl, int type);
 /* readdir.c */
 int fuse_readdir(struct file *file, struct dir_context *ctx);
 
+/**
+ * Return the number of bytes in an arguments list
+ */
+unsigned int fuse_len_args(unsigned int numargs, struct fuse_arg *args);
+
+/**
+ * Get the next unique ID for a request
+ */
+u64 fuse_get_unique(struct fuse_iqueue *fiq);
+void fuse_free_conn(struct fuse_conn *fc);
+
 #endif /* _FS_FUSE_I_H */

fs/fuse/inode.c

@@ -15,7 +15,8 @@
 #include <linux/init.h>
 #include <linux/module.h>
 #include <linux/moduleparam.h>
-#include <linux/parser.h>
+#include <linux/fs_context.h>
+#include <linux/fs_parser.h>
 #include <linux/statfs.h>
 #include <linux/random.h>
 #include <linux/sched.h>
@@ -59,24 +60,13 @@ MODULE_PARM_DESC(max_user_congthresh,
 /** Congestion starts at 75% of maximum */
 #define FUSE_DEFAULT_CONGESTION_THRESHOLD (FUSE_DEFAULT_MAX_BACKGROUND * 3 / 4)
 
-struct fuse_mount_data {
-	int fd;
-	unsigned rootmode;
-	kuid_t user_id;
-	kgid_t group_id;
-	unsigned fd_present:1;
-	unsigned rootmode_present:1;
-	unsigned user_id_present:1;
-	unsigned group_id_present:1;
-	unsigned default_permissions:1;
-	unsigned allow_other:1;
-	unsigned max_read;
-	unsigned blksize;
-};
+#ifdef CONFIG_BLOCK
+static struct file_system_type fuseblk_fs_type;
+#endif
 
 struct fuse_forget_link *fuse_alloc_forget(void)
 {
-	return kzalloc(sizeof(struct fuse_forget_link), GFP_KERNEL);
+	return kzalloc(sizeof(struct fuse_forget_link), GFP_KERNEL_ACCOUNT);
 }
 
 static struct inode *fuse_alloc_inode(struct super_block *sb)
@@ -374,19 +364,21 @@ void fuse_unlock_inode(struct inode *inode, bool locked)
 
 static void fuse_umount_begin(struct super_block *sb)
 {
-	fuse_abort_conn(get_fuse_conn_super(sb));
+	struct fuse_conn *fc = get_fuse_conn_super(sb);
+
+	if (!fc->no_force_umount)
+		fuse_abort_conn(fc);
 }
 
 static void fuse_send_destroy(struct fuse_conn *fc)
 {
-	struct fuse_req *req = fc->destroy_req;
-	if (req && fc->conn_init) {
-		fc->destroy_req = NULL;
-		req->in.h.opcode = FUSE_DESTROY;
-		__set_bit(FR_FORCE, &req->flags);
-		__clear_bit(FR_BACKGROUND, &req->flags);
-		fuse_request_send(fc, req);
-		fuse_put_request(fc, req);
+	if (fc->conn_init) {
+		FUSE_ARGS(args);
+
+		args.opcode = FUSE_DESTROY;
+		args.force = true;
+		args.nocreds = true;
+		fuse_simple_request(fc, &args);
 	}
 }
 
@@ -430,12 +422,12 @@ static int fuse_statfs(struct dentry *dentry, struct kstatfs *buf)
 	}
 
 	memset(&outarg, 0, sizeof(outarg));
-	args.in.numargs = 0;
-	args.in.h.opcode = FUSE_STATFS;
-	args.in.h.nodeid = get_node_id(d_inode(dentry));
-	args.out.numargs = 1;
-	args.out.args[0].size = sizeof(outarg);
-	args.out.args[0].value = &outarg;
+	args.in_numargs = 0;
+	args.opcode = FUSE_STATFS;
+	args.nodeid = get_node_id(d_inode(dentry));
+	args.out_numargs = 1;
+	args.out_args[0].size = sizeof(outarg);
+	args.out_args[0].value = &outarg;
 	err = fuse_simple_request(fc, &args);
 	if (!err)
 		convert_fuse_statfs(buf, &outarg.st);
@@ -443,6 +435,8 @@ static int fuse_statfs(struct dentry *dentry, struct kstatfs *buf)
 }
 
 enum {
+	OPT_SOURCE,
+	OPT_SUBTYPE,
 	OPT_FD,
 	OPT_ROOTMODE,
 	OPT_USER_ID,
@@ -454,111 +448,109 @@ enum {
 	OPT_ERR
 };
 
-static const match_table_t tokens = {
-	{OPT_FD,			"fd=%u"},
-	{OPT_ROOTMODE,			"rootmode=%o"},
-	{OPT_USER_ID,			"user_id=%u"},
-	{OPT_GROUP_ID,			"group_id=%u"},
-	{OPT_DEFAULT_PERMISSIONS,	"default_permissions"},
-	{OPT_ALLOW_OTHER,		"allow_other"},
-	{OPT_MAX_READ,			"max_read=%u"},
-	{OPT_BLKSIZE,			"blksize=%u"},
-	{OPT_ERR,			NULL}
+static const struct fs_parameter_spec fuse_param_specs[] = {
+	fsparam_string	("source",		OPT_SOURCE),
+	fsparam_u32	("fd",			OPT_FD),
+	fsparam_u32oct	("rootmode",		OPT_ROOTMODE),
+	fsparam_u32	("user_id",		OPT_USER_ID),
+	fsparam_u32	("group_id",		OPT_GROUP_ID),
+	fsparam_flag	("default_permissions",	OPT_DEFAULT_PERMISSIONS),
+	fsparam_flag	("allow_other",		OPT_ALLOW_OTHER),
+	fsparam_u32	("max_read",		OPT_MAX_READ),
+	fsparam_u32	("blksize",		OPT_BLKSIZE),
+	fsparam_string	("subtype",		OPT_SUBTYPE),
+	{}
+};
+
+static const struct fs_parameter_description fuse_fs_parameters = {
+	.name		= "fuse",
+	.specs		= fuse_param_specs,
 };
 
-static int fuse_match_uint(substring_t *s, unsigned int *res)
+static int fuse_parse_param(struct fs_context *fc, struct fs_parameter *param)
 {
-	int err = -ENOMEM;
-	char *buf = match_strdup(s);
-	if (buf) {
-		err = kstrtouint(buf, 10, res);
-		kfree(buf);
+	struct fs_parse_result result;
+	struct fuse_fs_context *ctx = fc->fs_private;
+	int opt;
+
+	opt = fs_parse(fc, &fuse_fs_parameters, param, &result);
+	if (opt < 0)
+		return opt;
+
+	switch (opt) {
+	case OPT_SOURCE:
+		if (fc->source)
+			return invalf(fc, "fuse: Multiple sources specified");
+		fc->source = param->string;
+		param->string = NULL;
+		break;
+
+	case OPT_SUBTYPE:
+		if (ctx->subtype)
+			return invalf(fc, "fuse: Multiple subtypes specified");
+		ctx->subtype = param->string;
+		param->string = NULL;
+		return 0;
+
+	case OPT_FD:
+		ctx->fd = result.uint_32;
+		ctx->fd_present = 1;
+		break;
+
+	case OPT_ROOTMODE:
+		if (!fuse_valid_type(result.uint_32))
+			return invalf(fc, "fuse: Invalid rootmode");
+		ctx->rootmode = result.uint_32;
+		ctx->rootmode_present = 1;
+		break;
+
+	case OPT_USER_ID:
+		ctx->user_id = make_kuid(fc->user_ns, result.uint_32);
+		if (!uid_valid(ctx->user_id))
+			return invalf(fc, "fuse: Invalid user_id");
+		ctx->user_id_present = 1;
+		break;
+
+	case OPT_GROUP_ID:
+		ctx->group_id = make_kgid(fc->user_ns, result.uint_32);
+		if (!gid_valid(ctx->group_id))
+			return invalf(fc, "fuse: Invalid group_id");
+		ctx->group_id_present = 1;
+		break;
+
+	case OPT_DEFAULT_PERMISSIONS:
+		ctx->default_permissions = 1;
+		break;
+
+	case OPT_ALLOW_OTHER:
+		ctx->allow_other = 1;
+		break;
+
+	case OPT_MAX_READ:
+		ctx->max_read = result.uint_32;
+		break;
+
+	case OPT_BLKSIZE:
+		if (!ctx->is_bdev)
+			return invalf(fc, "fuse: blksize only supported for fuseblk");
+		ctx->blksize = result.uint_32;
+		break;
+
+	default:
+		return -EINVAL;
 	}
-	return err;
+
+	return 0;
 }
 
-static int parse_fuse_opt(char *opt, struct fuse_mount_data *d, int is_bdev,
-			  struct user_namespace *user_ns)
+static void fuse_free_fc(struct fs_context *fc)
 {
-	char *p;
-	memset(d, 0, sizeof(struct fuse_mount_data));
-	d->max_read = ~0;
-	d->blksize = FUSE_DEFAULT_BLKSIZE;
-
-	while ((p = strsep(&opt, ",")) != NULL) {
-		int token;
-		int value;
-		unsigned uv;
-		substring_t args[MAX_OPT_ARGS];
-		if (!*p)
-			continue;
-
-		token = match_token(p, tokens, args);
-		switch (token) {
-		case OPT_FD:
-			if (match_int(&args[0], &value))
-				return 0;
-			d->fd = value;
-			d->fd_present = 1;
-			break;
-
-		case OPT_ROOTMODE:
-			if (match_octal(&args[0], &value))
-				return 0;
-			if (!fuse_valid_type(value))
-				return 0;
-			d->rootmode = value;
-			d->rootmode_present = 1;
-			break;
-
-		case OPT_USER_ID:
-			if (fuse_match_uint(&args[0], &uv))
-				return 0;
-			d->user_id = make_kuid(user_ns, uv);
-			if (!uid_valid(d->user_id))
-				return 0;
-			d->user_id_present = 1;
-			break;
-
-		case OPT_GROUP_ID:
-			if (fuse_match_uint(&args[0], &uv))
-				return 0;
-			d->group_id = make_kgid(user_ns, uv);
-			if (!gid_valid(d->group_id))
-				return 0;
-			d->group_id_present = 1;
-			break;
-
-		case OPT_DEFAULT_PERMISSIONS:
-			d->default_permissions = 1;
-			break;
-
-		case OPT_ALLOW_OTHER:
-			d->allow_other = 1;
-			break;
-
-		case OPT_MAX_READ:
-			if (match_int(&args[0], &value))
-				return 0;
-			d->max_read = value;
-			break;
-
-		case OPT_BLKSIZE:
-			if (!is_bdev || match_int(&args[0], &value))
-				return 0;
-			d->blksize = value;
-			break;
-
-		default:
-			return 0;
-		}
-	}
+	struct fuse_fs_context *ctx = fc->fs_private;
 
-	if (!d->fd_present || !d->rootmode_present ||
-	    !d->user_id_present || !d->group_id_present)
-		return 0;
-
-	return 1;
+	if (ctx) {
+		kfree(ctx->subtype);
+		kfree(ctx);
+	}
 }
 
 static int fuse_show_options(struct seq_file *m, struct dentry *root)
@@ -579,14 +571,19 @@ static int fuse_show_options(struct seq_file *m, struct dentry *root)
 	return 0;
 }
 
-static void fuse_iqueue_init(struct fuse_iqueue *fiq)
+static void fuse_iqueue_init(struct fuse_iqueue *fiq,
+			     const struct fuse_iqueue_ops *ops,
+			     void *priv)
 {
 	memset(fiq, 0, sizeof(struct fuse_iqueue));
+	spin_lock_init(&fiq->lock);
 	init_waitqueue_head(&fiq->waitq);
 	INIT_LIST_HEAD(&fiq->pending);
 	INIT_LIST_HEAD(&fiq->interrupts);
 	fiq->forget_list_tail = &fiq->forget_list_head;
 	fiq->connected = 1;
+	fiq->ops = ops;
+	fiq->priv = priv;
 }
 
 static void fuse_pqueue_init(struct fuse_pqueue *fpq)
@@ -600,7 +597,8 @@ static void fuse_pqueue_init(struct fuse_pqueue *fpq)
 	fpq->connected = 1;
 }
 
-void fuse_conn_init(struct fuse_conn *fc, struct user_namespace *user_ns)
+void fuse_conn_init(struct fuse_conn *fc, struct user_namespace *user_ns,
+		    const struct fuse_iqueue_ops *fiq_ops, void *fiq_priv)
 {
 	memset(fc, 0, sizeof(*fc));
 	spin_lock_init(&fc->lock);
@@ -609,8 +607,7 @@ void fuse_conn_init(struct fuse_conn *fc, struct user_namespace *user_ns)
 	refcount_set(&fc->count, 1);
 	atomic_set(&fc->dev_count, 1);
 	init_waitqueue_head(&fc->blocked_waitq);
-	init_waitqueue_head(&fc->reserved_req_waitq);
-	fuse_iqueue_init(&fc->iq);
+	fuse_iqueue_init(&fc->iq, fiq_ops, fiq_priv);
 	INIT_LIST_HEAD(&fc->bg_queue);
 	INIT_LIST_HEAD(&fc->entry);
 	INIT_LIST_HEAD(&fc->devices);
@@ -633,8 +630,6 @@ EXPORT_SYMBOL_GPL(fuse_conn_init);
 void fuse_conn_put(struct fuse_conn *fc)
 {
 	if (refcount_dec_and_test(&fc->count)) {
-		if (fc->destroy_req)
-			fuse_request_free(fc->destroy_req);
 		put_pid_ns(fc->pid_ns);
 		put_user_ns(fc->user_ns);
 		fc->release(fc);
@@ -822,9 +817,12 @@ static const struct super_operations fuse_super_operations = {
 
 static void sanitize_global_limit(unsigned *limit)
 {
+	/*
+	 * The default maximum number of async requests is calculated to consume
+	 * 1/2^13 of the total memory, assuming 392 bytes per request.
+	 */
 	if (*limit == 0)
-		*limit = ((totalram_pages() << PAGE_SHIFT) >> 13) /
-			 sizeof(struct fuse_req);
+		*limit = ((totalram_pages() << PAGE_SHIFT) >> 13) / 392;
 
 	if (*limit >= 1 << 16)
 		*limit = (1 << 16) - 1;
@@ -870,11 +868,19 @@ static void process_init_limits(struct fuse_conn *fc, struct fuse_init_out *arg)
 	spin_unlock(&fc->bg_lock);
 }
 
-static void process_init_reply(struct fuse_conn *fc, struct fuse_req *req)
+struct fuse_init_args {
+	struct fuse_args args;
+	struct fuse_init_in in;
+	struct fuse_init_out out;
+};
+
+static void process_init_reply(struct fuse_conn *fc, struct fuse_args *args,
+			       int error)
 {
-	struct fuse_init_out *arg = &req->misc.init_out;
+	struct fuse_init_args *ia = container_of(args, typeof(*ia), args);
+	struct fuse_init_out *arg = &ia->out;
 
-	if (req->out.h.error || arg->major != FUSE_KERNEL_VERSION)
+	if (error || arg->major != FUSE_KERNEL_VERSION)
 		fc->conn_error = 1;
 	else {
 		unsigned long ra_pages;
@@ -951,18 +957,23 @@ static void process_init_reply(struct fuse_conn *fc, struct fuse_req *req)
 		fc->max_write = max_t(unsigned, 4096, fc->max_write);
 		fc->conn_init = 1;
 	}
+	kfree(ia);
+
 	fuse_set_initialized(fc);
 	wake_up_all(&fc->blocked_waitq);
 }
 
-static void fuse_send_init(struct fuse_conn *fc, struct fuse_req *req)
+void fuse_send_init(struct fuse_conn *fc)
 {
-	struct fuse_init_in *arg = &req->misc.init_in;
+	struct fuse_init_args *ia;
+
+	ia = kzalloc(sizeof(*ia), GFP_KERNEL | __GFP_NOFAIL);
 
-	arg->major = FUSE_KERNEL_VERSION;
-	arg->minor = FUSE_KERNEL_MINOR_VERSION;
-	arg->max_readahead = fc->sb->s_bdi->ra_pages * PAGE_SIZE;
-	arg->flags |= FUSE_ASYNC_READ | FUSE_POSIX_LOCKS | FUSE_ATOMIC_O_TRUNC |
+	ia->in.major = FUSE_KERNEL_VERSION;
+	ia->in.minor = FUSE_KERNEL_MINOR_VERSION;
+	ia->in.max_readahead = fc->sb->s_bdi->ra_pages * PAGE_SIZE;
+	ia->in.flags |=
+		FUSE_ASYNC_READ | FUSE_POSIX_LOCKS | FUSE_ATOMIC_O_TRUNC |
 		FUSE_EXPORT_SUPPORT | FUSE_BIG_WRITES | FUSE_DONT_MASK |
 		FUSE_SPLICE_WRITE | FUSE_SPLICE_MOVE | FUSE_SPLICE_READ |
 		FUSE_FLOCK_LOCKS | FUSE_HAS_IOCTL_DIR | FUSE_AUTO_INVAL_DATA |
@@ -971,26 +982,32 @@ static void fuse_send_init(struct fuse_conn *fc, struct fuse_req *req)
 		FUSE_PARALLEL_DIROPS | FUSE_HANDLE_KILLPRIV | FUSE_POSIX_ACL |
 		FUSE_ABORT_ERROR | FUSE_MAX_PAGES | FUSE_CACHE_SYMLINKS |
 		FUSE_NO_OPENDIR_SUPPORT | FUSE_EXPLICIT_INVAL_DATA;
-	req->in.h.opcode = FUSE_INIT;
-	req->in.numargs = 1;
-	req->in.args[0].size = sizeof(*arg);
-	req->in.args[0].value = arg;
-	req->out.numargs = 1;
+	ia->args.opcode = FUSE_INIT;
+	ia->args.in_numargs = 1;
+	ia->args.in_args[0].size = sizeof(ia->in);
+	ia->args.in_args[0].value = &ia->in;
+	ia->args.out_numargs = 1;
 	/* Variable length argument used for backward compatibility
 	   with interface version < 7.5.  Rest of init_out is zeroed
 	   by do_get_request(), so a short reply is not a problem */
-	req->out.argvar = 1;
-	req->out.args[0].size = sizeof(struct fuse_init_out);
-	req->out.args[0].value = &req->misc.init_out;
-	req->end = process_init_reply;
-	fuse_request_send_background(fc, req);
+	ia->args.out_argvar = 1;
+	ia->args.out_args[0].size = sizeof(ia->out);
+	ia->args.out_args[0].value = &ia->out;
+	ia->args.force = true;
+	ia->args.nocreds = true;
+	ia->args.end = process_init_reply;
+
+	if (fuse_simple_background(fc, &ia->args, GFP_KERNEL) != 0)
+		process_init_reply(fc, &ia->args, -ENOTCONN);
 }
+EXPORT_SYMBOL_GPL(fuse_send_init);
 
-static void fuse_free_conn(struct fuse_conn *fc)
+void fuse_free_conn(struct fuse_conn *fc)
 {
 	WARN_ON(!list_empty(&fc->devices));
 	kfree_rcu(fc, rcu);
 }
+EXPORT_SYMBOL_GPL(fuse_free_conn);
 
 static int fuse_bdi_init(struct fuse_conn *fc, struct super_block *sb)
 {
@@ -1032,7 +1049,7 @@ static int fuse_bdi_init(struct fuse_conn *fc, struct super_block *sb)
 	return 0;
 }
 
-struct fuse_dev *fuse_dev_alloc(struct fuse_conn *fc)
+struct fuse_dev *fuse_dev_alloc(void)
 {
 	struct fuse_dev *fud;
 	struct list_head *pq;
@@ -1048,16 +1065,33 @@ struct fuse_dev *fuse_dev_alloc(struct fuse_conn *fc)
 	}
 
 	fud->pq.processing = pq;
-	fud->fc = fuse_conn_get(fc);
 	fuse_pqueue_init(&fud->pq);
 
+	return fud;
+}
+EXPORT_SYMBOL_GPL(fuse_dev_alloc);
+
+void fuse_dev_install(struct fuse_dev *fud, struct fuse_conn *fc)
+{
+	fud->fc = fuse_conn_get(fc);
 	spin_lock(&fc->lock);
 	list_add_tail(&fud->entry, &fc->devices);
 	spin_unlock(&fc->lock);
+}
+EXPORT_SYMBOL_GPL(fuse_dev_install);
 
+struct fuse_dev *fuse_dev_alloc_install(struct fuse_conn *fc)
+{
+	struct fuse_dev *fud;
+
+	fud = fuse_dev_alloc();
+	if (!fud)
+		return NULL;
+
+	fuse_dev_install(fud, fc);
 	return fud;
 }
-EXPORT_SYMBOL_GPL(fuse_dev_alloc);
+EXPORT_SYMBOL_GPL(fuse_dev_alloc_install);
 
 void fuse_dev_free(struct fuse_dev *fud)
 {
@@ -1075,17 +1109,13 @@ void fuse_dev_free(struct fuse_dev *fud)
 }
 EXPORT_SYMBOL_GPL(fuse_dev_free);
 
-static int fuse_fill_super(struct super_block *sb, void *data, int silent)
+int fuse_fill_super_common(struct super_block *sb, struct fuse_fs_context *ctx)
 {
 	struct fuse_dev *fud;
-	struct fuse_conn *fc;
+	struct fuse_conn *fc = get_fuse_conn_super(sb);
 	struct inode *root;
-	struct fuse_mount_data d;
-	struct file *file;
 	struct dentry *root_dentry;
-	struct fuse_req *init_req;
 	int err;
-	int is_bdev = sb->s_bdev != NULL;
 
 	err = -EINVAL;
 	if (sb->s_flags & SB_MANDLOCK)
@@ -1093,19 +1123,19 @@ static int fuse_fill_super(struct super_block *sb, void *data, int silent)
 
 	sb->s_flags &= ~(SB_NOSEC | SB_I_VERSION);
 
-	if (!parse_fuse_opt(data, &d, is_bdev, sb->s_user_ns))
-		goto err;
-
-	if (is_bdev) {
+	if (ctx->is_bdev) {
 #ifdef CONFIG_BLOCK
 		err = -EINVAL;
-		if (!sb_set_blocksize(sb, d.blksize))
+		if (!sb_set_blocksize(sb, ctx->blksize))
 			goto err;
 #endif
 	} else {
 		sb->s_blocksize = PAGE_SIZE;
 		sb->s_blocksize_bits = PAGE_SHIFT;
 	}
+
+	sb->s_subtype = ctx->subtype;
+	ctx->subtype = NULL;
 	sb->s_magic = FUSE_SUPER_MAGIC;
 	sb->s_op = &fuse_super_operations;
 	sb->s_xattr = fuse_xattr_handlers;
@@ -1116,19 +1146,6 @@ static int fuse_fill_super(struct super_block *sb, void *data, int silent)
 	if (sb->s_user_ns != &init_user_ns)
 		sb->s_iflags |= SB_I_UNTRUSTED_MOUNTER;
 
-	file = fget(d.fd);
-	err = -EINVAL;
-	if (!file)
-		goto err;
-
-	/*
-	 * Require mount to happen from the same user namespace which
-	 * opened /dev/fuse to prevent potential attacks.
-	 */
-	if (file->f_op != &fuse_dev_operations ||
-	    file->f_cred->user_ns != sb->s_user_ns)
-		goto err_fput;
-
 	/*
 	 * If we are not in the initial user namespace posix
 	 * acls must be translated.
@@ -1136,17 +1153,9 @@ static int fuse_fill_super(struct super_block *sb, void *data, int silent)
 	if (sb->s_user_ns != &init_user_ns)
 		sb->s_xattr = fuse_no_acl_xattr_handlers;
 
-	fc = kmalloc(sizeof(*fc), GFP_KERNEL);
-	err = -ENOMEM;
-	if (!fc)
-		goto err_fput;
-
-	fuse_conn_init(fc, sb->s_user_ns);
-	fc->release = fuse_free_conn;
-
-	fud = fuse_dev_alloc(fc);
+	fud = fuse_dev_alloc_install(fc);
 	if (!fud)
-		goto err_put_conn;
+		goto err;
 
 	fc->dev = sb->s_dev;
 	fc->sb = sb;
@@ -1159,17 +1168,17 @@ static int fuse_fill_super(struct super_block *sb, void *data, int silent)
 		fc->dont_mask = 1;
 	sb->s_flags |= SB_POSIXACL;
 
-	fc->default_permissions = d.default_permissions;
-	fc->allow_other = d.allow_other;
-	fc->user_id = d.user_id;
-	fc->group_id = d.group_id;
-	fc->max_read = max_t(unsigned, 4096, d.max_read);
-
-	/* Used by get_root_inode() */
-	sb->s_fs_info = fc;
+	fc->default_permissions = ctx->default_permissions;
+	fc->allow_other = ctx->allow_other;
+	fc->user_id = ctx->user_id;
+	fc->group_id = ctx->group_id;
+	fc->max_read = max_t(unsigned, 4096, ctx->max_read);
+	fc->destroy = ctx->destroy;
+	fc->no_control = ctx->no_control;
+	fc->no_force_umount = ctx->no_force_umount;
 
 	err = -ENOMEM;
-	root = fuse_get_root_inode(sb, d.rootmode);
+	root = fuse_get_root_inode(sb, ctx->rootmode);
 	sb->s_d_op = &fuse_root_dentry_operations;
 	root_dentry = d_make_root(root);
 	if (!root_dentry)
@@ -1177,20 +1186,9 @@ static int fuse_fill_super(struct super_block *sb, void *data, int silent)
 	/* Root dentry doesn't have .d_revalidate */
 	sb->s_d_op = &fuse_dentry_operations;
 
-	init_req = fuse_request_alloc(0);
-	if (!init_req)
-		goto err_put_root;
-	__set_bit(FR_BACKGROUND, &init_req->flags);
-
-	if (is_bdev) {
-		fc->destroy_req = fuse_request_alloc(0);
-		if (!fc->destroy_req)
-			goto err_free_init_req;
-	}
-
 	mutex_lock(&fuse_mutex);
 	err = -EINVAL;
-	if (file->private_data)
+	if (*ctx->fudptr)
 		goto err_unlock;
 
 	err = fuse_ctl_add_conn(fc);
@@ -1199,27 +1197,62 @@ static int fuse_fill_super(struct super_block *sb, void *data, int silent)
 
 	list_add_tail(&fc->entry, &fuse_conn_list);
 	sb->s_root = root_dentry;
-	file->private_data = fud;
+	*ctx->fudptr = fud;
 	mutex_unlock(&fuse_mutex);
+	return 0;
+
+ err_unlock:
+	mutex_unlock(&fuse_mutex);
+	dput(root_dentry);
+ err_dev_free:
+	fuse_dev_free(fud);
+ err:
+	return err;
+}
+EXPORT_SYMBOL_GPL(fuse_fill_super_common);
+
+static int fuse_fill_super(struct super_block *sb, struct fs_context *fsc)
+{
+	struct fuse_fs_context *ctx = fsc->fs_private;
+	struct file *file;
+	int err;
+	struct fuse_conn *fc;
+
+	err = -EINVAL;
+	file = fget(ctx->fd);
+	if (!file)
+		goto err;
+
+	/*
+	 * Require mount to happen from the same user namespace which
+	 * opened /dev/fuse to prevent potential attacks.
+	 */
+	if ((file->f_op != &fuse_dev_operations) ||
+	    (file->f_cred->user_ns != sb->s_user_ns))
+		goto err_fput;
+	ctx->fudptr = &file->private_data;
+
+	fc = kmalloc(sizeof(*fc), GFP_KERNEL);
+	err = -ENOMEM;
+	if (!fc)
+		goto err_fput;
+
+	fuse_conn_init(fc, sb->s_user_ns, &fuse_dev_fiq_ops, NULL);
+	fc->release = fuse_free_conn;
+	sb->s_fs_info = fc;
+
+	err = fuse_fill_super_common(sb, ctx);
+	if (err)
+		goto err_put_conn;
 	/*
 	 * atomic_dec_and_test() in fput() provides the necessary
 	 * memory barrier for file->private_data to be visible on all
 	 * CPUs after this
 	 */
 	fput(file);
-
-	fuse_send_init(fc, init_req);
-
+	fuse_send_init(get_fuse_conn_super(sb));
 	return 0;
 
- err_unlock:
-	mutex_unlock(&fuse_mutex);
- err_free_init_req:
-	fuse_request_free(init_req);
- err_put_root:
-	dput(root_dentry);
- err_dev_free:
-	fuse_dev_free(fud);
  err_put_conn:
 	fuse_conn_put(fc);
 	sb->s_fs_info = NULL;
@@ -1229,11 +1262,52 @@ static int fuse_fill_super(struct super_block *sb, void *data, int silent)
 	return err;
 }
 
-static struct dentry *fuse_mount(struct file_system_type *fs_type,
-		       int flags, const char *dev_name,
-		       void *raw_data)
+static int fuse_get_tree(struct fs_context *fc)
+{
+	struct fuse_fs_context *ctx = fc->fs_private;
+
+	if (!ctx->fd_present || !ctx->rootmode_present ||
+	    !ctx->user_id_present || !ctx->group_id_present)
+		return -EINVAL;
+
+#ifdef CONFIG_BLOCK
+	if (ctx->is_bdev)
+		return get_tree_bdev(fc, fuse_fill_super);
+#endif
+
+	return get_tree_nodev(fc, fuse_fill_super);
+}
+
+static const struct fs_context_operations fuse_context_ops = {
+	.free		= fuse_free_fc,
+	.parse_param	= fuse_parse_param,
+	.get_tree	= fuse_get_tree,
+};
+
+/*
+ * Set up the filesystem mount context.
+ */
+static int fuse_init_fs_context(struct fs_context *fc)
 {
-	return mount_nodev(fs_type, flags, raw_data, fuse_fill_super);
+	struct fuse_fs_context *ctx;
+
+	ctx = kzalloc(sizeof(struct fuse_fs_context), GFP_KERNEL);
+	if (!ctx)
+		return -ENOMEM;
+
+	ctx->max_read = ~0;
+	ctx->blksize = FUSE_DEFAULT_BLKSIZE;
+
+#ifdef CONFIG_BLOCK
+	if (fc->fs_type == &fuseblk_fs_type) {
+		ctx->is_bdev = true;
+		ctx->destroy = true;
+	}
+#endif
+
+	fc->fs_private = ctx;
+	fc->ops = &fuse_context_ops;
+	return 0;
 }
 
 static void fuse_sb_destroy(struct super_block *sb)
@@ -1241,7 +1315,8 @@ static void fuse_sb_destroy(struct super_block *sb)
 	struct fuse_conn *fc = get_fuse_conn_super(sb);
 
 	if (fc) {
-		fuse_send_destroy(fc);
+		if (fc->destroy)
+			fuse_send_destroy(fc);
 
 		fuse_abort_conn(fc);
 		fuse_wait_aborted(fc);
@@ -1252,29 +1327,24 @@ static void fuse_sb_destroy(struct super_block *sb)
 	}
 }
 
-static void fuse_kill_sb_anon(struct super_block *sb)
+void fuse_kill_sb_anon(struct super_block *sb)
 {
 	fuse_sb_destroy(sb);
 	kill_anon_super(sb);
 }
+EXPORT_SYMBOL_GPL(fuse_kill_sb_anon);
 
 static struct file_system_type fuse_fs_type = {
 	.owner		= THIS_MODULE,
 	.name		= "fuse",
 	.fs_flags	= FS_HAS_SUBTYPE | FS_USERNS_MOUNT,
-	.mount		= fuse_mount,
+	.init_fs_context = fuse_init_fs_context,
+	.parameters	= &fuse_fs_parameters,
 	.kill_sb	= fuse_kill_sb_anon,
 };
 MODULE_ALIAS_FS("fuse");
 
 #ifdef CONFIG_BLOCK
-static struct dentry *fuse_mount_blk(struct file_system_type *fs_type,
-			   int flags, const char *dev_name,
-			   void *raw_data)
-{
-	return mount_bdev(fs_type, flags, dev_name, raw_data, fuse_fill_super);
-}
-
 static void fuse_kill_sb_blk(struct super_block *sb)
 {
 	fuse_sb_destroy(sb);
@@ -1284,7 +1354,8 @@ static void fuse_kill_sb_blk(struct super_block *sb)
 static struct file_system_type fuseblk_fs_type = {
 	.owner		= THIS_MODULE,
 	.name		= "fuseblk",
-	.mount		= fuse_mount_blk,
+	.init_fs_context = fuse_init_fs_context,
+	.parameters	= &fuse_fs_parameters,
 	.kill_sb	= fuse_kill_sb_blk,
 	.fs_flags	= FS_REQUIRES_DEV | FS_HAS_SUBTYPE,
 };

fs/fuse/readdir.c

@@ -249,6 +249,27 @@ static int fuse_direntplus_link(struct file *file,
 	return 0;
 }
 
+static void fuse_force_forget(struct file *file, u64 nodeid)
+{
+	struct inode *inode = file_inode(file);
+	struct fuse_conn *fc = get_fuse_conn(inode);
+	struct fuse_forget_in inarg;
+	FUSE_ARGS(args);
+
+	memset(&inarg, 0, sizeof(inarg));
+	inarg.nlookup = 1;
+	args.opcode = FUSE_FORGET;
+	args.nodeid = nodeid;
+	args.in_numargs = 1;
+	args.in_args[0].size = sizeof(inarg);
+	args.in_args[0].value = &inarg;
+	args.force = true;
+	args.noreply = true;
+
+	fuse_simple_request(fc, &args);
+	/* ignore errors */
+}
+
 static int parse_dirplusfile(char *buf, size_t nbytes, struct file *file,
 			     struct dir_context *ctx, u64 attr_version)
 {
@@ -295,62 +316,55 @@ static int parse_dirplusfile(char *buf, size_t nbytes, struct file *file,
 
 static int fuse_readdir_uncached(struct file *file, struct dir_context *ctx)
 {
-	int plus, err;
-	size_t nbytes;
+	int plus;
+	ssize_t res;
 	struct page *page;
 	struct inode *inode = file_inode(file);
 	struct fuse_conn *fc = get_fuse_conn(inode);
-	struct fuse_req *req;
+	struct fuse_io_args ia = {};
+	struct fuse_args_pages *ap = &ia.ap;
+	struct fuse_page_desc desc = { .length = PAGE_SIZE };
 	u64 attr_version = 0;
 	bool locked;
 
-	req = fuse_get_req(fc, 1);
-	if (IS_ERR(req))
-		return PTR_ERR(req);
-
 	page = alloc_page(GFP_KERNEL);
-	if (!page) {
-		fuse_put_request(fc, req);
+	if (!page)
 		return -ENOMEM;
-	}
 
 	plus = fuse_use_readdirplus(inode, ctx);
-	req->out.argpages = 1;
-	req->num_pages = 1;
-	req->pages[0] = page;
-	req->page_descs[0].length = PAGE_SIZE;
+	ap->args.out_pages = 1;
+	ap->num_pages = 1;
+	ap->pages = &page;
+	ap->descs = &desc;
 	if (plus) {
 		attr_version = fuse_get_attr_version(fc);
-		fuse_read_fill(req, file, ctx->pos, PAGE_SIZE,
-			       FUSE_READDIRPLUS);
+		fuse_read_args_fill(&ia, file, ctx->pos, PAGE_SIZE,
+				    FUSE_READDIRPLUS);
 	} else {
-		fuse_read_fill(req, file, ctx->pos, PAGE_SIZE,
-			       FUSE_READDIR);
+		fuse_read_args_fill(&ia, file, ctx->pos, PAGE_SIZE,
+				    FUSE_READDIR);
 	}
 	locked = fuse_lock_inode(inode);
-	fuse_request_send(fc, req);
+	res = fuse_simple_request(fc, &ap->args);
 	fuse_unlock_inode(inode, locked);
-	nbytes = req->out.args[0].size;
-	err = req->out.h.error;
-	fuse_put_request(fc, req);
-	if (!err) {
-		if (!nbytes) {
+	if (res >= 0) {
+		if (!res) {
 			struct fuse_file *ff = file->private_data;
 
 			if (ff->open_flags & FOPEN_CACHE_DIR)
 				fuse_readdir_cache_end(file, ctx->pos);
 		} else if (plus) {
-			err = parse_dirplusfile(page_address(page), nbytes,
+			res = parse_dirplusfile(page_address(page), res,
 						file, ctx, attr_version);
 		} else {
-			err = parse_dirfile(page_address(page), nbytes, file,
+			res = parse_dirfile(page_address(page), res, file,
 					    ctx);
 		}
 	}
 
 	__free_page(page);
 	fuse_invalidate_atime(inode);
-	return err;
+	return res;
 }
 
 enum fuse_parse_result {
@@ -372,11 +386,13 @@ static enum fuse_parse_result fuse_parse_cache(struct fuse_file *ff,
 	for (;;) {
 		struct fuse_dirent *dirent = addr + offset;
 		unsigned int nbytes = size - offset;
-		size_t reclen = FUSE_DIRENT_SIZE(dirent);
+		size_t reclen;
 
 		if (nbytes < FUSE_NAME_OFFSET || !dirent->namelen)
 			break;
 
+		reclen = FUSE_DIRENT_SIZE(dirent); /* derefs ->namelen */
+
 		if (WARN_ON(dirent->namelen > FUSE_NAME_MAX))
 			return FOUND_ERR;
 		if (WARN_ON(reclen > nbytes))

fs/fuse/xattr.c

@@ -25,15 +25,15 @@ int fuse_setxattr(struct inode *inode, const char *name, const void *value,
 	memset(&inarg, 0, sizeof(inarg));
 	inarg.size = size;
 	inarg.flags = flags;
-	args.in.h.opcode = FUSE_SETXATTR;
-	args.in.h.nodeid = get_node_id(inode);
-	args.in.numargs = 3;
-	args.in.args[0].size = sizeof(inarg);
-	args.in.args[0].value = &inarg;
-	args.in.args[1].size = strlen(name) + 1;
-	args.in.args[1].value = name;
-	args.in.args[2].size = size;
-	args.in.args[2].value = value;
+	args.opcode = FUSE_SETXATTR;
+	args.nodeid = get_node_id(inode);
+	args.in_numargs = 3;
+	args.in_args[0].size = sizeof(inarg);
+	args.in_args[0].value = &inarg;
+	args.in_args[1].size = strlen(name) + 1;
+	args.in_args[1].value = name;
+	args.in_args[2].size = size;
+	args.in_args[2].value = value;
 	err = fuse_simple_request(fc, &args);
 	if (err == -ENOSYS) {
 		fc->no_setxattr = 1;
@@ -60,22 +60,22 @@ ssize_t fuse_getxattr(struct inode *inode, const char *name, void *value,
 
 	memset(&inarg, 0, sizeof(inarg));
 	inarg.size = size;
-	args.in.h.opcode = FUSE_GETXATTR;
-	args.in.h.nodeid = get_node_id(inode);
-	args.in.numargs = 2;
-	args.in.args[0].size = sizeof(inarg);
-	args.in.args[0].value = &inarg;
-	args.in.args[1].size = strlen(name) + 1;
-	args.in.args[1].value = name;
+	args.opcode = FUSE_GETXATTR;
+	args.nodeid = get_node_id(inode);
+	args.in_numargs = 2;
+	args.in_args[0].size = sizeof(inarg);
+	args.in_args[0].value = &inarg;
+	args.in_args[1].size = strlen(name) + 1;
+	args.in_args[1].value = name;
 	/* This is really two different operations rolled into one */
-	args.out.numargs = 1;
+	args.out_numargs = 1;
 	if (size) {
-		args.out.argvar = 1;
-		args.out.args[0].size = size;
-		args.out.args[0].value = value;
+		args.out_argvar = true;
+		args.out_args[0].size = size;
+		args.out_args[0].value = value;
 	} else {
-		args.out.args[0].size = sizeof(outarg);
-		args.out.args[0].value = &outarg;
+		args.out_args[0].size = sizeof(outarg);
+		args.out_args[0].value = &outarg;
 	}
 	ret = fuse_simple_request(fc, &args);
 	if (!ret && !size)
@@ -121,20 +121,20 @@ ssize_t fuse_listxattr(struct dentry *entry, char *list, size_t size)
 
 	memset(&inarg, 0, sizeof(inarg));
 	inarg.size = size;
-	args.in.h.opcode = FUSE_LISTXATTR;
-	args.in.h.nodeid = get_node_id(inode);
-	args.in.numargs = 1;
-	args.in.args[0].size = sizeof(inarg);
-	args.in.args[0].value = &inarg;
+	args.opcode = FUSE_LISTXATTR;
+	args.nodeid = get_node_id(inode);
+	args.in_numargs = 1;
+	args.in_args[0].size = sizeof(inarg);
+	args.in_args[0].value = &inarg;
 	/* This is really two different operations rolled into one */
-	args.out.numargs = 1;
+	args.out_numargs = 1;
 	if (size) {
-		args.out.argvar = 1;
-		args.out.args[0].size = size;
-		args.out.args[0].value = list;
+		args.out_argvar = true;
+		args.out_args[0].size = size;
+		args.out_args[0].value = list;
 	} else {
-		args.out.args[0].size = sizeof(outarg);
-		args.out.args[0].value = &outarg;
+		args.out_args[0].size = sizeof(outarg);
+		args.out_args[0].value = &outarg;
 	}
 	ret = fuse_simple_request(fc, &args);
 	if (!ret && !size)
@@ -157,11 +157,11 @@ int fuse_removexattr(struct inode *inode, const char *name)
 	if (fc->no_removexattr)
 		return -EOPNOTSUPP;
 
-	args.in.h.opcode = FUSE_REMOVEXATTR;
-	args.in.h.nodeid = get_node_id(inode);
-	args.in.numargs = 1;
-	args.in.args[0].size = strlen(name) + 1;
-	args.in.args[0].value = name;
+	args.opcode = FUSE_REMOVEXATTR;
+	args.nodeid = get_node_id(inode);
+	args.in_numargs = 1;
+	args.in_args[0].size = strlen(name) + 1;
+	args.in_args[0].value = name;
 	err = fuse_simple_request(fc, &args);
 	if (err == -ENOSYS) {
 		fc->no_removexattr = 1;

fs/namespace.c

@@ -2802,8 +2802,6 @@ static int do_new_mount(struct path *path, const char *fstype, int sb_flags,
 				put_filesystem(type);
 				return -EINVAL;
 			}
-		} else {
-			subtype = "";
 		}
 	}
 

fs/proc_namespace.c

@@ -88,7 +88,7 @@ static inline void mangle(struct seq_file *m, const char *s)
 static void show_type(struct seq_file *m, struct super_block *sb)
 {
 	mangle(m, sb->s_type->name);
-	if (sb->s_subtype && sb->s_subtype[0]) {
+	if (sb->s_subtype) {
 		seq_putc(m, '.');
 		mangle(m, sb->s_subtype);
 	}

fs/super.c

@@ -1555,11 +1555,6 @@ int vfs_get_tree(struct fs_context *fc)
 	sb = fc->root->d_sb;
 	WARN_ON(!sb->s_bdi);
 
-	if (fc->subtype && !sb->s_subtype) {
-		sb->s_subtype = fc->subtype;
-		fc->subtype = NULL;
-	}
-
 	/*
 	 * Write barrier is for super_cache_count(). We place it before setting
 	 * SB_BORN as the data dependency between the two functions is the

include/linux/fs_context.h

@@ -95,7 +95,6 @@ struct fs_context {
 	const struct cred	*cred;		/* The mounter's credentials */
 	struct fc_log		*log;		/* Logging buffer */
 	const char		*source;	/* The source name (eg. dev path) */
-	const char		*subtype;	/* The subtype to set on the superblock */
 	void			*security;	/* Linux S&M options */
 	void			*s_fs_info;	/* Proposed s_fs_info */
 	unsigned int		sb_flags;	/* Proposed superblock flags (SB_*) */

include/uapi/linux/fuse.h

@@ -425,6 +425,10 @@ enum fuse_opcode {
 
 	/* CUSE specific operations */
 	CUSE_INIT		= 4096,
+
+	/* Reserved opcodes: helpful to detect structure endian-ness */
+	CUSE_INIT_BSWAP_RESERVED	= 1048576,	/* CUSE_INIT << 8 */
+	FUSE_INIT_BSWAP_RESERVED	= 436207616,	/* FUSE_INIT << 24 */
 };
 
 enum fuse_notify_code {