Merge tag 'fuse-update-5.1' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuse

Pull fuse updates from Miklos Szeredi:
 "Scalability and performance improvements, as well as minor bug fixes
  and cleanups"

* tag 'fuse-update-5.1' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuse: (25 commits)
  fuse: cache readdir calls if filesystem opts out of opendir
  fuse: support clients that don't implement 'opendir'
  fuse: lift bad inode checks into callers
  fuse: multiplex cached/direct_io file operations
  fuse add copy_file_range to direct io fops
  fuse: use iov_iter based generic splice helpers
  fuse: Switch to using async direct IO for FOPEN_DIRECT_IO
  fuse: use atomic64_t for khctr
  fuse: clean up aborted
  fuse: Protect ff->reserved_req via corresponding fi->lock
  fuse: Protect fi->nlookup with fi->lock
  fuse: Introduce fi->lock to protect write related fields
  fuse: Convert fc->attr_version into atomic64_t
  fuse: Add fuse_inode argument to fuse_prepare_release()
  fuse: Verify userspace asks to requeue interrupt that we really sent
  fuse: Do some refactoring in fuse_dev_do_write()
  fuse: Wake up req->waitq of only if not background
  fuse: Optimize request_end() by not taking fiq->waitq.lock
  fuse: Kill fasync only if interrupt is queued in queue_interrupt()
  fuse: Remove stale comment in end_requests()
  ...

1 files changed, 191 insertions, 151 deletions

diff --git a/fs/fuse/file.c b/fs/fuse/file.c
index a59c16bd90ac..06096b60f1df 100644
--- a/fs/fuse/file.c
+++ b/fs/fuse/file.c
@@ -19,8 +19,6 @@
 #include <linux/falloc.h>
 #include <linux/uio.h>
 
-static const struct file_operations fuse_direct_io_file_operations;
-
 static int fuse_send_open(struct fuse_conn *fc, u64 nodeid, struct file *file,
 			  int opcode, struct fuse_open_out *outargp)
 {
@@ -64,9 +62,7 @@ struct fuse_file *fuse_file_alloc(struct fuse_conn *fc)
 	RB_CLEAR_NODE(&ff->polled_node);
 	init_waitqueue_head(&ff->poll_wait);
 
-	spin_lock(&fc->lock);
-	ff->kh = ++fc->khctr;
-	spin_unlock(&fc->lock);
+	ff->kh = atomic64_inc_return(&fc->khctr);
 
 	return ff;
 }
@@ -94,7 +90,7 @@ 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;
 
-		if (ff->fc->no_open && !isdir) {
+		if (isdir ? ff->fc->no_opendir : ff->fc->no_open) {
 			/*
 			 * Drop the release request when client does not
 			 * implement 'open'
@@ -128,8 +124,9 @@ int fuse_do_open(struct fuse_conn *fc, u64 nodeid, struct file *file,
 		return -ENOMEM;
 
 	ff->fh = 0;
-	ff->open_flags = FOPEN_KEEP_CACHE; /* Default for no-open */
-	if (!fc->no_open || isdir) {
+	/* Default for no-open */
+	ff->open_flags = FOPEN_KEEP_CACHE | (isdir ? FOPEN_CACHE_DIR : 0);
+	if (isdir ? !fc->no_opendir : !fc->no_open) {
 		struct fuse_open_out outarg;
 		int err;
 
@@ -138,11 +135,14 @@ int fuse_do_open(struct fuse_conn *fc, u64 nodeid, struct file *file,
 			ff->fh = outarg.fh;
 			ff->open_flags = outarg.open_flags;
 
-		} else if (err != -ENOSYS || isdir) {
+		} else if (err != -ENOSYS) {
 			fuse_file_free(ff);
 			return err;
 		} else {
-			fc->no_open = 1;
+			if (isdir)
+				fc->no_opendir = 1;
+			else
+				fc->no_open = 1;
 		}
 	}
 
@@ -159,17 +159,16 @@ EXPORT_SYMBOL_GPL(fuse_do_open);
 static void fuse_link_write_file(struct file *file)
 {
 	struct inode *inode = file_inode(file);
-	struct fuse_conn *fc = get_fuse_conn(inode);
 	struct fuse_inode *fi = get_fuse_inode(inode);
 	struct fuse_file *ff = file->private_data;
 	/*
 	 * file may be written through mmap, so chain it onto the
 	 * inodes's write_file list
 	 */
-	spin_lock(&fc->lock);
+	spin_lock(&fi->lock);
 	if (list_empty(&ff->write_entry))
 		list_add(&ff->write_entry, &fi->write_files);
-	spin_unlock(&fc->lock);
+	spin_unlock(&fi->lock);
 }
 
 void fuse_finish_open(struct inode *inode, struct file *file)
@@ -177,8 +176,6 @@ void fuse_finish_open(struct inode *inode, struct file *file)
 	struct fuse_file *ff = file->private_data;
 	struct fuse_conn *fc = get_fuse_conn(inode);
 
-	if (ff->open_flags & FOPEN_DIRECT_IO)
-		file->f_op = &fuse_direct_io_file_operations;
 	if (!(ff->open_flags & FOPEN_KEEP_CACHE))
 		invalidate_inode_pages2(inode->i_mapping);
 	if (ff->open_flags & FOPEN_NONSEEKABLE)
@@ -186,10 +183,10 @@ void fuse_finish_open(struct inode *inode, struct file *file)
 	if (fc->atomic_o_trunc && (file->f_flags & O_TRUNC)) {
 		struct fuse_inode *fi = get_fuse_inode(inode);
 
-		spin_lock(&fc->lock);
-		fi->attr_version = ++fc->attr_version;
+		spin_lock(&fi->lock);
+		fi->attr_version = atomic64_inc_return(&fc->attr_version);
 		i_size_write(inode, 0);
-		spin_unlock(&fc->lock);
+		spin_unlock(&fi->lock);
 		fuse_invalidate_attr(inode);
 		if (fc->writeback_cache)
 			file_update_time(file);
@@ -224,14 +221,20 @@ int fuse_open_common(struct inode *inode, struct file *file, bool isdir)
 	return err;
 }
 
-static void fuse_prepare_release(struct fuse_file *ff, int flags, int opcode)
+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;
 
+	/* Inode is NULL on error path of fuse_create_open() */
+	if (likely(fi)) {
+		spin_lock(&fi->lock);
+		list_del(&ff->write_entry);
+		spin_unlock(&fi->lock);
+	}
 	spin_lock(&fc->lock);
-	list_del(&ff->write_entry);
 	if (!RB_EMPTY_NODE(&ff->polled_node))
 		rb_erase(&ff->polled_node, &fc->polled_files);
 	spin_unlock(&fc->lock);
@@ -249,11 +252,12 @@ static void fuse_prepare_release(struct fuse_file *ff, int flags, int opcode)
 
 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;
 	int opcode = isdir ? FUSE_RELEASEDIR : FUSE_RELEASE;
 
-	fuse_prepare_release(ff, file->f_flags, opcode);
+	fuse_prepare_release(fi, ff, file->f_flags, opcode);
 
 	if (ff->flock) {
 		struct fuse_release_in *inarg = &req->misc.release.in;
@@ -295,10 +299,10 @@ static int fuse_release(struct inode *inode, struct file *file)
 	return 0;
 }
 
-void fuse_sync_release(struct fuse_file *ff, int flags)
+void fuse_sync_release(struct fuse_inode *fi, struct fuse_file *ff, int flags)
 {
 	WARN_ON(refcount_read(&ff->count) > 1);
-	fuse_prepare_release(ff, flags, FUSE_RELEASE);
+	fuse_prepare_release(fi, ff, flags, FUSE_RELEASE);
 	/*
 	 * iput(NULL) is a no-op and since the refcount is 1 and everything's
 	 * synchronous, we are fine with not doing igrab() here"
@@ -329,33 +333,39 @@ u64 fuse_lock_owner_id(struct fuse_conn *fc, fl_owner_t id)
 	return (u64) v0 + ((u64) v1 << 32);
 }
 
-/*
- * Check if any page in a range is under writeback
- *
- * This is currently done by walking the list of writepage requests
- * for the inode, which can be pretty inefficient.
- */
-static bool fuse_range_is_writeback(struct inode *inode, pgoff_t idx_from,
-				   pgoff_t idx_to)
+static struct fuse_req *fuse_find_writeback(struct fuse_inode *fi,
+					    pgoff_t idx_from, pgoff_t idx_to)
 {
-	struct fuse_conn *fc = get_fuse_conn(inode);
-	struct fuse_inode *fi = get_fuse_inode(inode);
 	struct fuse_req *req;
-	bool found = false;
 
-	spin_lock(&fc->lock);
 	list_for_each_entry(req, &fi->writepages, writepages_entry) {
 		pgoff_t curr_index;
 
-		BUG_ON(req->inode != inode);
+		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 &&
 		    curr_index <= idx_to) {
-			found = true;
-			break;
+			return req;
 		}
 	}
-	spin_unlock(&fc->lock);
+	return NULL;
+}
+
+/*
+ * Check if any page in a range is under writeback
+ *
+ * This is currently done by walking the list of writepage requests
+ * for the inode, which can be pretty inefficient.
+ */
+static bool fuse_range_is_writeback(struct inode *inode, pgoff_t idx_from,
+				   pgoff_t idx_to)
+{
+	struct fuse_inode *fi = get_fuse_inode(inode);
+	bool found;
+
+	spin_lock(&fi->lock);
+	found = fuse_find_writeback(fi, idx_from, idx_to);
+	spin_unlock(&fi->lock);
 
 	return found;
 }
@@ -598,9 +608,9 @@ static void fuse_aio_complete(struct fuse_io_priv *io, int err, ssize_t pos)
 			struct fuse_conn *fc = get_fuse_conn(inode);
 			struct fuse_inode *fi = get_fuse_inode(inode);
 
-			spin_lock(&fc->lock);
-			fi->attr_version = ++fc->attr_version;
-			spin_unlock(&fc->lock);
+			spin_lock(&fi->lock);
+			fi->attr_version = atomic64_inc_return(&fc->attr_version);
+			spin_unlock(&fi->lock);
 		}
 
 		io->iocb->ki_complete(io->iocb, res, 0);
@@ -675,13 +685,13 @@ static void fuse_read_update_size(struct inode *inode, loff_t size,
 	struct fuse_conn *fc = get_fuse_conn(inode);
 	struct fuse_inode *fi = get_fuse_inode(inode);
 
-	spin_lock(&fc->lock);
+	spin_lock(&fi->lock);
 	if (attr_ver == fi->attr_version && size < inode->i_size &&
 	    !test_bit(FUSE_I_SIZE_UNSTABLE, &fi->state)) {
-		fi->attr_version = ++fc->attr_version;
+		fi->attr_version = atomic64_inc_return(&fc->attr_version);
 		i_size_write(inode, size);
 	}
-	spin_unlock(&fc->lock);
+	spin_unlock(&fi->lock);
 }
 
 static void fuse_short_read(struct fuse_req *req, struct inode *inode,
@@ -919,7 +929,7 @@ out:
 	return err;
 }
 
-static ssize_t fuse_file_read_iter(struct kiocb *iocb, struct iov_iter *to)
+static ssize_t fuse_cache_read_iter(struct kiocb *iocb, struct iov_iter *to)
 {
 	struct inode *inode = iocb->ki_filp->f_mapping->host;
 	struct fuse_conn *fc = get_fuse_conn(inode);
@@ -996,13 +1006,13 @@ bool fuse_write_update_size(struct inode *inode, loff_t pos)
 	struct fuse_inode *fi = get_fuse_inode(inode);
 	bool ret = false;
 
-	spin_lock(&fc->lock);
-	fi->attr_version = ++fc->attr_version;
+	spin_lock(&fi->lock);
+	fi->attr_version = atomic64_inc_return(&fc->attr_version);
 	if (pos > inode->i_size) {
 		i_size_write(inode, pos);
 		ret = true;
 	}
-	spin_unlock(&fc->lock);
+	spin_unlock(&fi->lock);
 
 	return ret;
 }
@@ -1125,9 +1135,6 @@ static ssize_t fuse_perform_write(struct kiocb *iocb,
 	int err = 0;
 	ssize_t res = 0;
 
-	if (is_bad_inode(inode))
-		return -EIO;
-
 	if (inode->i_size < pos + iov_iter_count(ii))
 		set_bit(FUSE_I_SIZE_UNSTABLE, &fi->state);
 
@@ -1173,7 +1180,7 @@ static ssize_t fuse_perform_write(struct kiocb *iocb,
 	return res > 0 ? res : err;
 }
 
-static ssize_t fuse_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
+static ssize_t fuse_cache_write_iter(struct kiocb *iocb, struct iov_iter *from)
 {
 	struct file *file = iocb->ki_filp;
 	struct address_space *mapping = file->f_mapping;
@@ -1416,9 +1423,6 @@ static ssize_t __fuse_direct_read(struct fuse_io_priv *io,
 	ssize_t res;
 	struct inode *inode = file_inode(io->iocb->ki_filp);
 
-	if (is_bad_inode(inode))
-		return -EIO;
-
 	res = fuse_direct_io(io, iter, ppos, 0);
 
 	fuse_invalidate_atime(inode);
@@ -1426,10 +1430,21 @@ static ssize_t __fuse_direct_read(struct fuse_io_priv *io,
 	return res;
 }
 
+static ssize_t fuse_direct_IO(struct kiocb *iocb, struct iov_iter *iter);
+
 static ssize_t fuse_direct_read_iter(struct kiocb *iocb, struct iov_iter *to)
 {
-	struct fuse_io_priv io = FUSE_IO_PRIV_SYNC(iocb);
-	return __fuse_direct_read(&io, to, &iocb->ki_pos);
+	ssize_t res;
+
+	if (!is_sync_kiocb(iocb) && iocb->ki_flags & IOCB_DIRECT) {
+		res = fuse_direct_IO(iocb, to);
+	} else {
+		struct fuse_io_priv io = FUSE_IO_PRIV_SYNC(iocb);
+
+		res = __fuse_direct_read(&io, to, &iocb->ki_pos);
+	}
+
+	return res;
 }
 
 static ssize_t fuse_direct_write_iter(struct kiocb *iocb, struct iov_iter *from)
@@ -1438,14 +1453,17 @@ static ssize_t fuse_direct_write_iter(struct kiocb *iocb, struct iov_iter *from)
 	struct fuse_io_priv io = FUSE_IO_PRIV_SYNC(iocb);
 	ssize_t res;
 
-	if (is_bad_inode(inode))
-		return -EIO;
-
 	/* Don't allow parallel writes to the same file */
 	inode_lock(inode);
 	res = generic_write_checks(iocb, from);
-	if (res > 0)
-		res = fuse_direct_io(&io, from, &iocb->ki_pos, FUSE_DIO_WRITE);
+	if (res > 0) {
+		if (!is_sync_kiocb(iocb) && iocb->ki_flags & IOCB_DIRECT) {
+			res = fuse_direct_IO(iocb, from);
+		} else {
+			res = fuse_direct_io(&io, from, &iocb->ki_pos,
+					     FUSE_DIO_WRITE);
+		}
+	}
 	fuse_invalidate_attr(inode);
 	if (res > 0)
 		fuse_write_update_size(inode, iocb->ki_pos);
@@ -1454,6 +1472,34 @@ static ssize_t fuse_direct_write_iter(struct kiocb *iocb, struct iov_iter *from)
 	return res;
 }
 
+static ssize_t fuse_file_read_iter(struct kiocb *iocb, struct iov_iter *to)
+{
+	struct file *file = iocb->ki_filp;
+	struct fuse_file *ff = file->private_data;
+
+	if (is_bad_inode(file_inode(file)))
+		return -EIO;
+
+	if (!(ff->open_flags & FOPEN_DIRECT_IO))
+		return fuse_cache_read_iter(iocb, to);
+	else
+		return fuse_direct_read_iter(iocb, to);
+}
+
+static ssize_t fuse_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
+{
+	struct file *file = iocb->ki_filp;
+	struct fuse_file *ff = file->private_data;
+
+	if (is_bad_inode(file_inode(file)))
+		return -EIO;
+
+	if (!(ff->open_flags & FOPEN_DIRECT_IO))
+		return fuse_cache_write_iter(iocb, from);
+	else
+		return fuse_direct_write_iter(iocb, from);
+}
+
 static void fuse_writepage_free(struct fuse_conn *fc, struct fuse_req *req)
 {
 	int i;
@@ -1481,20 +1527,18 @@ static void fuse_writepage_finish(struct fuse_conn *fc, struct fuse_req *req)
 	wake_up(&fi->page_waitq);
 }
 
-/* Called under fc->lock, may release and reacquire it */
+/* 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)
-__releases(fc->lock)
-__acquires(fc->lock)
+__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;
 
-	if (!fc->connected)
-		goto out_free;
-
 	if (inarg->offset + data_size <= size) {
 		inarg->size = data_size;
 	} else if (inarg->offset < size) {
@@ -1505,28 +1549,40 @@ __acquires(fc->lock)
 	}
 
 	req->in.args[1].size = inarg->size;
-	fi->writectr++;
 	queued = fuse_request_queue_background(fc, req);
-	WARN_ON(!queued);
+	/* Fails on broken connection only */
+	if (unlikely(!queued))
+		goto out_free;
+
+	fi->writectr++;
 	return;
 
  out_free:
 	fuse_writepage_finish(fc, req);
-	spin_unlock(&fc->lock);
+	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);
+	}
+
 	fuse_writepage_free(fc, req);
 	fuse_put_request(fc, req);
-	spin_lock(&fc->lock);
+	spin_lock(&fi->lock);
 }
 
 /*
  * If fi->writectr is positive (no truncate or fsync going on) send
  * all queued writepage requests.
  *
- * Called with fc->lock
+ * Called with fi->lock
  */
 void fuse_flush_writepages(struct inode *inode)
-__releases(fc->lock)
-__acquires(fc->lock)
+__releases(fi->lock)
+__acquires(fi->lock)
 {
 	struct fuse_conn *fc = get_fuse_conn(inode);
 	struct fuse_inode *fi = get_fuse_inode(inode);
@@ -1546,7 +1602,7 @@ static void fuse_writepage_end(struct fuse_conn *fc, struct fuse_req *req)
 	struct fuse_inode *fi = get_fuse_inode(inode);
 
 	mapping_set_error(inode->i_mapping, req->out.h.error);
-	spin_lock(&fc->lock);
+	spin_lock(&fi->lock);
 	while (req->misc.write.next) {
 		struct fuse_conn *fc = get_fuse_conn(inode);
 		struct fuse_write_in *inarg = &req->misc.write.in;
@@ -1583,7 +1639,7 @@ static void fuse_writepage_end(struct fuse_conn *fc, struct fuse_req *req)
 	}
 	fi->writectr--;
 	fuse_writepage_finish(fc, req);
-	spin_unlock(&fc->lock);
+	spin_unlock(&fi->lock);
 	fuse_writepage_free(fc, req);
 }
 
@@ -1592,13 +1648,13 @@ static struct fuse_file *__fuse_write_file_get(struct fuse_conn *fc,
 {
 	struct fuse_file *ff = NULL;
 
-	spin_lock(&fc->lock);
+	spin_lock(&fi->lock);
 	if (!list_empty(&fi->write_files)) {
 		ff = list_entry(fi->write_files.next, struct fuse_file,
 				write_entry);
 		fuse_file_get(ff);
 	}
-	spin_unlock(&fc->lock);
+	spin_unlock(&fi->lock);
 
 	return ff;
 }
@@ -1669,11 +1725,11 @@ static int fuse_writepage_locked(struct page *page)
 	inc_wb_stat(&inode_to_bdi(inode)->wb, WB_WRITEBACK);
 	inc_node_page_state(tmp_page, NR_WRITEBACK_TEMP);
 
-	spin_lock(&fc->lock);
+	spin_lock(&fi->lock);
 	list_add(&req->writepages_entry, &fi->writepages);
 	list_add_tail(&req->list, &fi->queued_writes);
 	fuse_flush_writepages(inode);
-	spin_unlock(&fc->lock);
+	spin_unlock(&fi->lock);
 
 	end_page_writeback(page);
 
@@ -1722,21 +1778,27 @@ static void fuse_writepages_send(struct fuse_fill_wb_data *data)
 {
 	struct fuse_req *req = data->req;
 	struct inode *inode = data->inode;
-	struct fuse_conn *fc = get_fuse_conn(inode);
 	struct fuse_inode *fi = get_fuse_inode(inode);
 	int num_pages = req->num_pages;
 	int i;
 
 	req->ff = fuse_file_get(data->ff);
-	spin_lock(&fc->lock);
+	spin_lock(&fi->lock);
 	list_add_tail(&req->list, &fi->queued_writes);
 	fuse_flush_writepages(inode);
-	spin_unlock(&fc->lock);
+	spin_unlock(&fi->lock);
 
 	for (i = 0; i < num_pages; i++)
 		end_page_writeback(data->orig_pages[i]);
 }
 
+/*
+ * First recheck under fi->lock if the offending offset is still under
+ * writeback.  If yes, then iterate auxiliary write requests, to see if there's
+ * one already added for a page at this offset.  If there's none, then insert
+ * 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,
 				     struct page *page)
 {
@@ -1744,57 +1806,50 @@ static bool fuse_writepage_in_flight(struct fuse_req *new_req,
 	struct fuse_inode *fi = get_fuse_inode(new_req->inode);
 	struct fuse_req *tmp;
 	struct fuse_req *old_req;
-	bool found = false;
-	pgoff_t curr_index;
 
-	BUG_ON(new_req->num_pages != 0);
+	WARN_ON(new_req->num_pages != 0);
 
-	spin_lock(&fc->lock);
+	spin_lock(&fi->lock);
 	list_del(&new_req->writepages_entry);
-	list_for_each_entry(old_req, &fi->writepages, writepages_entry) {
-		BUG_ON(old_req->inode != new_req->inode);
-		curr_index = old_req->misc.write.in.offset >> PAGE_SHIFT;
-		if (curr_index <= page->index &&
-		    page->index < curr_index + old_req->num_pages) {
-			found = true;
-			break;
-		}
-	}
-	if (!found) {
+	old_req = fuse_find_writeback(fi, page->index, page->index);
+	if (!old_req) {
 		list_add(&new_req->writepages_entry, &fi->writepages);
-		goto out_unlock;
+		spin_unlock(&fi->lock);
+		return false;
 	}
 
 	new_req->num_pages = 1;
-	for (tmp = old_req; tmp != NULL; tmp = tmp->misc.write.next) {
-		BUG_ON(tmp->inode != new_req->inode);
+	for (tmp = old_req->misc.write.next; tmp; tmp = tmp->misc.write.next) {
+		pgoff_t curr_index;
+
+		WARN_ON(tmp->inode != new_req->inode);
 		curr_index = tmp->misc.write.in.offset >> PAGE_SHIFT;
-		if (tmp->num_pages == 1 &&
-		    curr_index == page->index) {
-			old_req = tmp;
+		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]);
+			break;
 		}
 	}
 
-	if (old_req->num_pages == 1 && test_bit(FR_PENDING, &old_req->flags)) {
-		struct backing_dev_info *bdi = inode_to_bdi(page->mapping->host);
+	if (!tmp) {
+		new_req->misc.write.next = old_req->misc.write.next;
+		old_req->misc.write.next = new_req;
+	}
+
+	spin_unlock(&fi->lock);
 
-		copy_highpage(old_req->pages[0], page);
-		spin_unlock(&fc->lock);
+	if (tmp) {
+		struct backing_dev_info *bdi = inode_to_bdi(new_req->inode);
 
 		dec_wb_stat(&bdi->wb, WB_WRITEBACK);
 		dec_node_page_state(new_req->pages[0], NR_WRITEBACK_TEMP);
 		wb_writeout_inc(&bdi->wb);
 		fuse_writepage_free(fc, new_req);
 		fuse_request_free(new_req);
-		goto out;
-	} else {
-		new_req->misc.write.next = old_req->misc.write.next;
-		old_req->misc.write.next = new_req;
 	}
-out_unlock:
-	spin_unlock(&fc->lock);
-out:
-	return found;
+
+	return true;
 }
 
 static int fuse_writepages_fill(struct page *page,
@@ -1803,6 +1858,7 @@ static int fuse_writepages_fill(struct page *page,
 	struct fuse_fill_wb_data *data = _data;
 	struct fuse_req *req = data->req;
 	struct inode *inode = data->inode;
+	struct fuse_inode *fi = get_fuse_inode(inode);
 	struct fuse_conn *fc = get_fuse_conn(inode);
 	struct page *tmp_page;
 	bool is_writeback;
@@ -1873,9 +1929,9 @@ static int fuse_writepages_fill(struct page *page,
 		req->end = fuse_writepage_end;
 		req->inode = inode;
 
-		spin_lock(&fc->lock);
+		spin_lock(&fi->lock);
 		list_add(&req->writepages_entry, &fi->writepages);
-		spin_unlock(&fc->lock);
+		spin_unlock(&fi->lock);
 
 		data->req = req;
 	}
@@ -1898,12 +1954,12 @@ static int fuse_writepages_fill(struct page *page,
 	data->orig_pages[req->num_pages] = page;
 
 	/*
-	 * Protected by fc->lock against concurrent access by
+	 * Protected by fi->lock against concurrent access by
 	 * fuse_page_is_writeback().
 	 */
-	spin_lock(&fc->lock);
+	spin_lock(&fi->lock);
 	req->num_pages++;
-	spin_unlock(&fc->lock);
+	spin_unlock(&fi->lock);
 
 out_unlock:
 	unlock_page(page);
@@ -2087,6 +2143,18 @@ static const struct vm_operations_struct fuse_file_vm_ops = {
 
 static int fuse_file_mmap(struct file *file, struct vm_area_struct *vma)
 {
+	struct fuse_file *ff = file->private_data;
+
+	if (ff->open_flags & FOPEN_DIRECT_IO) {
+		/* Can't provide the coherency needed for MAP_SHARED */
+		if (vma->vm_flags & VM_MAYSHARE)
+			return -ENODEV;
+
+		invalidate_inode_pages2(file->f_mapping);
+
+		return generic_file_mmap(file, vma);
+	}
+
 	if ((vma->vm_flags & VM_SHARED) && (vma->vm_flags & VM_MAYWRITE))
 		fuse_link_write_file(file);
 
@@ -2095,17 +2163,6 @@ static int fuse_file_mmap(struct file *file, struct vm_area_struct *vma)
 	return 0;
 }
 
-static int fuse_direct_mmap(struct file *file, struct vm_area_struct *vma)
-{
-	/* Can't provide the coherency needed for MAP_SHARED */
-	if (vma->vm_flags & VM_MAYSHARE)
-		return -ENODEV;
-
-	invalidate_inode_pages2(file->f_mapping);
-
-	return generic_file_mmap(file, vma);
-}
-
 static int convert_fuse_file_lock(struct fuse_conn *fc,
 				  const struct fuse_file_lock *ffl,
 				  struct file_lock *fl)
@@ -3114,6 +3171,7 @@ static const struct file_operations fuse_file_operations = {
 	.lock		= fuse_file_lock,
 	.flock		= fuse_file_flock,
 	.splice_read	= generic_file_splice_read,
+	.splice_write	= iter_file_splice_write,
 	.unlocked_ioctl	= fuse_file_ioctl,
 	.compat_ioctl	= fuse_file_compat_ioctl,
 	.poll		= fuse_file_poll,
@@ -3121,24 +3179,6 @@ static const struct file_operations fuse_file_operations = {
 	.copy_file_range = fuse_copy_file_range,
 };
 
-static const struct file_operations fuse_direct_io_file_operations = {
-	.llseek		= fuse_file_llseek,
-	.read_iter	= fuse_direct_read_iter,
-	.write_iter	= fuse_direct_write_iter,
-	.mmap		= fuse_direct_mmap,
-	.open		= fuse_open,
-	.flush		= fuse_flush,
-	.release	= fuse_release,
-	.fsync		= fuse_fsync,
-	.lock		= fuse_file_lock,
-	.flock		= fuse_file_flock,
-	.unlocked_ioctl	= fuse_file_ioctl,
-	.compat_ioctl	= fuse_file_compat_ioctl,
-	.poll		= fuse_file_poll,
-	.fallocate	= fuse_file_fallocate,
-	/* no splice_read */
-};
-
 static const struct address_space_operations fuse_file_aops  = {
 	.readpage	= fuse_readpage,
 	.writepage	= fuse_writepage,