Re: [PATCH 2/2] fuse: remove tmp folio for writebacks and internal rb tree

[Shakeel Butt <shakeel.butt@linux.dev>]

On Fri, Oct 11, 2024 at 03:34:34PM GMT, Joanne Koong wrote:
> Currently, we allocate and copy data to a temporary folio when
> handling writeback in order to mitigate the following deadlock scenario
> that may arise if reclaim waits on writeback to complete:
> * single-threaded FUSE server is in the middle of handling a request
>   that needs a memory allocation
> * memory allocation triggers direct reclaim
> * direct reclaim waits on a folio under writeback
> * the FUSE server can't write back the folio since it's stuck in
>   direct reclaim
> 
> To work around this, we allocate a temporary folio and copy over the
> original folio to the temporary folio so that writeback can be
> immediately cleared on the original folio. This additionally requires us
> to maintain an internal rb tree to keep track of writeback state on the
> temporary folios.
> 
> This change sets the address space operations flag
> ASOP_NO_RECLAIM_IN_WRITEBACK so that FUSE folios are not reclaimed and

I couldn't find where ASOP_NO_RECLAIM_IN_WRITEBACK is being set for
fuse.

> waited on while in writeback, and removes the temporary folio +
> extra copying and the internal rb tree.
> 
> fio benchmarks --
> (using averages observed from 10 runs, throwing away outliers)
> 
> Setup:
> sudo mount -t tmpfs -o size=30G tmpfs ~/tmp_mount
>  ./libfuse/build/example/passthrough_ll -o writeback -o max_threads=4 -o source=~/tmp_mount ~/fuse_mount
> 
> fio --name=writeback --ioengine=sync --rw=write --bs={1k,4k,1M} --size=2G
> --numjobs=2 --ramp_time=30 --group_reporting=1 --directory=/root/fuse_mount
> 
>         bs =  1k          4k            1M
> Before  351 MiB/s     1818 MiB/s     1851 MiB/s
> After   341 MiB/s     2246 MiB/s     2685 MiB/s
> % diff        -3%          23%         45%
> 
> Signed-off-by: Joanne Koong <joannelkoong@gmail.com>
> ---
>  fs/fuse/file.c | 321 +++++--------------------------------------------
>  1 file changed, 27 insertions(+), 294 deletions(-)
> 
> diff --git a/fs/fuse/file.c b/fs/fuse/file.c
> index 4304e44f32e6..9fee9f3062db 100644
> --- a/fs/fuse/file.c
> +++ b/fs/fuse/file.c
> @@ -415,74 +415,11 @@ u64 fuse_lock_owner_id(struct fuse_conn *fc, fl_owner_t id)
>  
>  struct fuse_writepage_args {
>  	struct fuse_io_args ia;
> -	struct rb_node writepages_entry;
>  	struct list_head queue_entry;
> -	struct fuse_writepage_args *next;
>  	struct inode *inode;
>  	struct fuse_sync_bucket *bucket;
>  };
>  
> -static struct fuse_writepage_args *fuse_find_writeback(struct fuse_inode *fi,
> -					    pgoff_t idx_from, pgoff_t idx_to)
> -{
> -	struct rb_node *n;
> -
> -	n = fi->writepages.rb_node;
> -
> -	while (n) {
> -		struct fuse_writepage_args *wpa;
> -		pgoff_t curr_index;
> -
> -		wpa = rb_entry(n, struct fuse_writepage_args, writepages_entry);
> -		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)
> -			n = n->rb_right;
> -		else if (idx_to < curr_index)
> -			n = n->rb_left;
> -		else
> -			return wpa;
> -	}
> -	return NULL;
> -}
> -
> -/*
> - * Check if any page in a range is under writeback
> - */
> -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;
> -
> -	if (RB_EMPTY_ROOT(&fi->writepages))
> -		return false;
> -
> -	spin_lock(&fi->lock);
> -	found = fuse_find_writeback(fi, idx_from, idx_to);
> -	spin_unlock(&fi->lock);
> -
> -	return found;
> -}
> -
> -static inline bool fuse_page_is_writeback(struct inode *inode, pgoff_t index)
> -{
> -	return fuse_range_is_writeback(inode, index, index);
> -}
> -
> -/*
> - * Wait for page writeback to be completed.
> - *
> - * Since fuse doesn't rely on the VM writeback tracking, this has to
> - * use some other means.
> - */
> -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));
> -}
> -
>  /*
>   * Wait for all pending writepages on the inode to finish.
>   *
> @@ -876,7 +813,7 @@ static int fuse_do_readpage(struct file *file, struct page *page)
>  	 * page-cache page, so make sure we read a properly synced
>  	 * page.
>  	 */
> -	fuse_wait_on_page_writeback(inode, page->index);
> +	folio_wait_writeback(page_folio(page));
>  
>  	attr_ver = fuse_get_attr_version(fm->fc);
>  
> @@ -1024,8 +961,7 @@ static void fuse_readahead(struct readahead_control *rac)
>  		ap = &ia->ap;
>  		nr_pages = __readahead_batch(rac, ap->pages, nr_pages);
>  		for (i = 0; i < nr_pages; i++) {
> -			fuse_wait_on_page_writeback(inode,
> -						    readahead_index(rac) + i);
> +			folio_wait_writeback(page_folio(ap->pages[i]));
>  			ap->descs[i].length = PAGE_SIZE;
>  		}
>  		ap->num_pages = nr_pages;
> @@ -1147,7 +1083,7 @@ static ssize_t fuse_send_write_pages(struct fuse_io_args *ia,
>  	int err;
>  
>  	for (i = 0; i < ap->num_pages; i++)
> -		fuse_wait_on_page_writeback(inode, ap->pages[i]->index);
> +		folio_wait_writeback(page_folio(ap->pages[i]));
>  
>  	fuse_write_args_fill(ia, ff, pos, count);
>  	ia->write.in.flags = fuse_write_flags(iocb);
> @@ -1583,7 +1519,7 @@ ssize_t fuse_direct_io(struct fuse_io_priv *io, struct iov_iter *iter,
>  			return res;
>  		}
>  	}
> -	if (!cuse && fuse_range_is_writeback(inode, idx_from, idx_to)) {
> +	if (!cuse && filemap_range_has_writeback(mapping, pos, (pos + count - 1))) {
>  		if (!write)
>  			inode_lock(inode);
>  		fuse_sync_writes(inode);
> @@ -1780,13 +1716,17 @@ static ssize_t fuse_splice_write(struct pipe_inode_info *pipe, struct file *out,
>  static void fuse_writepage_free(struct fuse_writepage_args *wpa)
>  {
>  	struct fuse_args_pages *ap = &wpa->ia.ap;
> +	struct folio *folio;
>  	int i;
>  
>  	if (wpa->bucket)
>  		fuse_sync_bucket_dec(wpa->bucket);
>  
> -	for (i = 0; i < ap->num_pages; i++)
> -		__free_page(ap->pages[i]);
> +	for (i = 0; i < ap->num_pages; i++) {
> +		folio = page_folio(ap->pages[i]);
> +		folio_end_writeback(folio);
> +		folio_put(folio);
> +	}
>  
>  	fuse_file_put(wpa->ia.ff, false);
>  
> @@ -1799,7 +1739,7 @@ static void fuse_writepage_finish_stat(struct inode *inode, struct page *page)
>  	struct backing_dev_info *bdi = inode_to_bdi(inode);
>  
>  	dec_wb_stat(&bdi->wb, WB_WRITEBACK);
> -	dec_node_page_state(page, NR_WRITEBACK_TEMP);
> +	dec_node_page_state(page, NR_WRITEBACK);
>  	wb_writeout_inc(&bdi->wb);
>  }
>  
> @@ -1822,7 +1762,6 @@ static void fuse_send_writepage(struct fuse_mount *fm,
>  __releases(fi->lock)
>  __acquires(fi->lock)
>  {
> -	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;
> @@ -1858,18 +1797,8 @@ __acquires(fi->lock)
>  
>   out_free:
>  	fi->writectr--;
> -	rb_erase(&wpa->writepages_entry, &fi->writepages);
>  	fuse_writepage_finish(wpa);
>  	spin_unlock(&fi->lock);
> -
> -	/* After rb_erase() aux request list is private */
> -	for (aux = wpa->next; aux; aux = next) {
> -		next = aux->next;
> -		aux->next = NULL;
> -		fuse_writepage_finish_stat(aux->inode, aux->ia.ap.pages[0]);
> -		fuse_writepage_free(aux);
> -	}
> -
>  	fuse_writepage_free(wpa);
>  	spin_lock(&fi->lock);
>  }
> @@ -1897,43 +1826,6 @@ __acquires(fi->lock)
>  	}
>  }
>  
> -static struct fuse_writepage_args *fuse_insert_writeback(struct rb_root *root,
> -						struct fuse_writepage_args *wpa)
> -{
> -	pgoff_t idx_from = wpa->ia.write.in.offset >> PAGE_SHIFT;
> -	pgoff_t idx_to = idx_from + wpa->ia.ap.num_pages - 1;
> -	struct rb_node **p = &root->rb_node;
> -	struct rb_node  *parent = NULL;
> -
> -	WARN_ON(!wpa->ia.ap.num_pages);
> -	while (*p) {
> -		struct fuse_writepage_args *curr;
> -		pgoff_t curr_index;
> -
> -		parent = *p;
> -		curr = rb_entry(parent, struct fuse_writepage_args,
> -				writepages_entry);
> -		WARN_ON(curr->inode != wpa->inode);
> -		curr_index = curr->ia.write.in.offset >> PAGE_SHIFT;
> -
> -		if (idx_from >= curr_index + curr->ia.ap.num_pages)
> -			p = &(*p)->rb_right;
> -		else if (idx_to < curr_index)
> -			p = &(*p)->rb_left;
> -		else
> -			return curr;
> -	}
> -
> -	rb_link_node(&wpa->writepages_entry, parent, p);
> -	rb_insert_color(&wpa->writepages_entry, root);
> -	return NULL;
> -}
> -
> -static void tree_insert(struct rb_root *root, struct fuse_writepage_args *wpa)
> -{
> -	WARN_ON(fuse_insert_writeback(root, wpa));
> -}
> -
>  static void fuse_writepage_end(struct fuse_mount *fm, struct fuse_args *args,
>  			       int error)
>  {
> @@ -1953,41 +1845,6 @@ static void fuse_writepage_end(struct fuse_mount *fm, struct fuse_args *args,
>  	if (!fc->writeback_cache)
>  		fuse_invalidate_attr_mask(inode, FUSE_STATX_MODIFY);
>  	spin_lock(&fi->lock);
> -	rb_erase(&wpa->writepages_entry, &fi->writepages);
> -	while (wpa->next) {
> -		struct fuse_mount *fm = get_fuse_mount(inode);
> -		struct fuse_write_in *inarg = &wpa->ia.write.in;
> -		struct fuse_writepage_args *next = wpa->next;
> -
> -		wpa->next = next->next;
> -		next->next = NULL;
> -		tree_insert(&fi->writepages, next);
> -
> -		/*
> -		 * Skip fuse_flush_writepages() to make it easy to crop requests
> -		 * based on primary request size.
> -		 *
> -		 * 1st case (trivial): there are no concurrent activities using
> -		 * fuse_set/release_nowrite.  Then we're on safe side because
> -		 * fuse_flush_writepages() would call fuse_send_writepage()
> -		 * anyway.
> -		 *
> -		 * 2nd case: someone called fuse_set_nowrite and it is waiting
> -		 * now for completion of all in-flight requests.  This happens
> -		 * rarely and no more than once per page, so this should be
> -		 * okay.
> -		 *
> -		 * 3rd case: someone (e.g. fuse_do_setattr()) is in the middle
> -		 * of fuse_set_nowrite..fuse_release_nowrite section.  The fact
> -		 * that fuse_set_nowrite returned implies that all in-flight
> -		 * requests were completed along with all of their secondary
> -		 * requests.  Further primary requests are blocked by negative
> -		 * writectr.  Hence there cannot be any in-flight requests and
> -		 * no invocations of fuse_writepage_end() while we're in
> -		 * fuse_set_nowrite..fuse_release_nowrite section.
> -		 */
> -		fuse_send_writepage(fm, next, inarg->offset + inarg->size);
> -	}
>  	fi->writectr--;
>  	fuse_writepage_finish(wpa);
>  	spin_unlock(&fi->lock);
> @@ -2074,19 +1931,18 @@ static void fuse_writepage_add_to_bucket(struct fuse_conn *fc,
>  }
>  
>  static void fuse_writepage_args_page_fill(struct fuse_writepage_args *wpa, struct folio *folio,
> -					  struct folio *tmp_folio, uint32_t page_index)
> +					  uint32_t page_index)
>  {
>  	struct inode *inode = folio->mapping->host;
>  	struct fuse_args_pages *ap = &wpa->ia.ap;
>  
> -	folio_copy(tmp_folio, folio);
> -
> -	ap->pages[page_index] = &tmp_folio->page;
> +	folio_get(folio);
> +	ap->pages[page_index] = &folio->page;
>  	ap->descs[page_index].offset = 0;
>  	ap->descs[page_index].length = PAGE_SIZE;
>  
>  	inc_wb_stat(&inode_to_bdi(inode)->wb, WB_WRITEBACK);
> -	inc_node_page_state(&tmp_folio->page, NR_WRITEBACK_TEMP);
> +	inc_node_page_state(&folio->page, NR_WRITEBACK);
>  }
>  
>  static struct fuse_writepage_args *fuse_writepage_args_setup(struct folio *folio,
> @@ -2121,18 +1977,12 @@ static int fuse_writepage_locked(struct folio *folio)
>  	struct fuse_inode *fi = get_fuse_inode(inode);
>  	struct fuse_writepage_args *wpa;
>  	struct fuse_args_pages *ap;
> -	struct folio *tmp_folio;
>  	struct fuse_file *ff;
> -	int error = -ENOMEM;
> -
> -	tmp_folio = folio_alloc(GFP_NOFS | __GFP_HIGHMEM, 0);
> -	if (!tmp_folio)
> -		goto err;
> +	int error = -EIO;
>  
> -	error = -EIO;
>  	ff = fuse_write_file_get(fi);
>  	if (!ff)
> -		goto err_nofile;
> +		goto err;
>  
>  	wpa = fuse_writepage_args_setup(folio, ff);
>  	error = -ENOMEM;
> @@ -2143,22 +1993,17 @@ static int fuse_writepage_locked(struct folio *folio)
>  	ap->num_pages = 1;
>  
>  	folio_start_writeback(folio);
> -	fuse_writepage_args_page_fill(wpa, folio, tmp_folio, 0);
> +	fuse_writepage_args_page_fill(wpa, folio, 0);
>  
>  	spin_lock(&fi->lock);
> -	tree_insert(&fi->writepages, wpa);
>  	list_add_tail(&wpa->queue_entry, &fi->queued_writes);
>  	fuse_flush_writepages(inode);
>  	spin_unlock(&fi->lock);
>  
> -	folio_end_writeback(folio);
> -
>  	return 0;
>  
>  err_writepage_args:
>  	fuse_file_put(ff, false);
> -err_nofile:
> -	folio_put(tmp_folio);
>  err:
>  	mapping_set_error(folio->mapping, error);
>  	return error;
> @@ -2168,7 +2013,6 @@ struct fuse_fill_wb_data {
>  	struct fuse_writepage_args *wpa;
>  	struct fuse_file *ff;
>  	struct inode *inode;
> -	struct page **orig_pages;
>  	unsigned int max_pages;
>  };
>  
> @@ -2203,68 +2047,11 @@ static void fuse_writepages_send(struct fuse_fill_wb_data *data)
>  	struct fuse_writepage_args *wpa = data->wpa;
>  	struct inode *inode = data->inode;
>  	struct fuse_inode *fi = get_fuse_inode(inode);
> -	int num_pages = wpa->ia.ap.num_pages;
> -	int i;
>  
>  	spin_lock(&fi->lock);
>  	list_add_tail(&wpa->queue_entry, &fi->queued_writes);
>  	fuse_flush_writepages(inode);
>  	spin_unlock(&fi->lock);
> -
> -	for (i = 0; i < num_pages; i++)
> -		end_page_writeback(data->orig_pages[i]);
> -}
> -
> -/*
> - * Check under fi->lock if the page is under writeback, and insert it onto the
> - * rb_tree if not. Otherwise 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
> - * swapping the new temp page with the old one.
> - */
> -static bool fuse_writepage_add(struct fuse_writepage_args *new_wpa,
> -			       struct page *page)
> -{
> -	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_ap->num_pages != 0);
> -	new_ap->num_pages = 1;
> -
> -	spin_lock(&fi->lock);
> -	old_wpa = fuse_insert_writeback(&fi->writepages, new_wpa);
> -	if (!old_wpa) {
> -		spin_unlock(&fi->lock);
> -		return true;
> -	}
> -
> -	for (tmp = old_wpa->next; tmp; tmp = tmp->next) {
> -		pgoff_t curr_index;
> -
> -		WARN_ON(tmp->inode != new_wpa->inode);
> -		curr_index = tmp->ia.write.in.offset >> PAGE_SHIFT;
> -		if (curr_index == page->index) {
> -			WARN_ON(tmp->ia.ap.num_pages != 1);
> -			swap(tmp->ia.ap.pages[0], new_ap->pages[0]);
> -			break;
> -		}
> -	}
> -
> -	if (!tmp) {
> -		new_wpa->next = old_wpa->next;
> -		old_wpa->next = new_wpa;
> -	}
> -
> -	spin_unlock(&fi->lock);
> -
> -	if (tmp) {
> -		fuse_writepage_finish_stat(new_wpa->inode, new_ap->pages[0]);
> -		fuse_writepage_free(new_wpa);
> -	}
> -
> -	return false;
>  }
>  
>  static bool fuse_writepage_need_send(struct fuse_conn *fc, struct page *page,
> @@ -2273,15 +2060,6 @@ static bool fuse_writepage_need_send(struct fuse_conn *fc, struct page *page,
>  {
>  	WARN_ON(!ap->num_pages);
>  
> -	/*
> -	 * Being under writeback is unlikely but possible.  For example direct
> -	 * read to an mmaped fuse file will set the page dirty twice; once when
> -	 * the pages are faulted with get_user_pages(), and then after the read
> -	 * completed.
> -	 */
> -	if (fuse_page_is_writeback(data->inode, page->index))
> -		return true;
> -
>  	/* Reached max pages */
>  	if (ap->num_pages == fc->max_pages)
>  		return true;
> @@ -2291,7 +2069,7 @@ static bool fuse_writepage_need_send(struct fuse_conn *fc, struct page *page,
>  		return true;
>  
>  	/* Discontinuity */
> -	if (data->orig_pages[ap->num_pages - 1]->index + 1 != page->index)
> +	if (ap->pages[ap->num_pages - 1]->index + 1 != page->index)
>  		return true;
>  
>  	/* Need to grow the pages array?  If so, did the expansion fail? */
> @@ -2308,9 +2086,7 @@ static int fuse_writepages_fill(struct folio *folio,
>  	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);
> -	struct folio *tmp_folio;
>  	int err;
>  
>  	if (wpa && fuse_writepage_need_send(fc, &folio->page, ap, data)) {
> @@ -2318,54 +2094,23 @@ static int fuse_writepages_fill(struct folio *folio,
>  		data->wpa = NULL;
>  	}
>  
> -	err = -ENOMEM;
> -	tmp_folio = folio_alloc(GFP_NOFS | __GFP_HIGHMEM, 0);
> -	if (!tmp_folio)
> -		goto out_unlock;
> -
> -	/*
> -	 * The page must not be redirtied until the writeout is completed
> -	 * (i.e. userspace has sent a reply to the write request).  Otherwise
> -	 * there could be more than one temporary page instance for each real
> -	 * 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 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->wpa == NULL) {
>  		err = -ENOMEM;
>  		wpa = fuse_writepage_args_setup(folio, data->ff);
> -		if (!wpa) {
> -			folio_put(tmp_folio);
> +		if (!wpa)
>  			goto out_unlock;
> -		}
>  		fuse_file_get(wpa->ia.ff);
>  		data->max_pages = 1;
>  		ap = &wpa->ia.ap;
>  	}
>  	folio_start_writeback(folio);
>  
> -	fuse_writepage_args_page_fill(wpa, folio, tmp_folio, ap->num_pages);
> -	data->orig_pages[ap->num_pages] = &folio->page;
> +	fuse_writepage_args_page_fill(wpa, folio, ap->num_pages);
>  
>  	err = 0;
> -	if (data->wpa) {
> -		/*
> -		 * Protected by fi->lock against concurrent access by
> -		 * fuse_page_is_writeback().
> -		 */
> -		spin_lock(&fi->lock);
> -		ap->num_pages++;
> -		spin_unlock(&fi->lock);
> -	} else if (fuse_writepage_add(wpa, &folio->page)) {
> +	ap->num_pages++;
> +	if (!data->wpa)
>  		data->wpa = wpa;
> -	} else {
> -		folio_end_writeback(folio);
> -	}
>  out_unlock:
>  	folio_unlock(folio);
>  
> @@ -2394,21 +2139,12 @@ static int fuse_writepages(struct address_space *mapping,
>  	if (!data.ff)
>  		return -EIO;
>  
> -	err = -ENOMEM;
> -	data.orig_pages = kcalloc(fc->max_pages,
> -				  sizeof(struct page *),
> -				  GFP_NOFS);
> -	if (!data.orig_pages)
> -		goto out;
> -
>  	err = write_cache_pages(mapping, wbc, fuse_writepages_fill, &data);
>  	if (data.wpa) {
>  		WARN_ON(!data.wpa->ia.ap.num_pages);
>  		fuse_writepages_send(&data);
>  	}
>  
> -	kfree(data.orig_pages);
> -out:
>  	fuse_file_put(data.ff, false);
>  	return err;
>  }
> @@ -2433,7 +2169,7 @@ static int fuse_write_begin(struct file *file, struct address_space *mapping,
>  	if (IS_ERR(folio))
>  		goto error;
>  
> -	fuse_wait_on_page_writeback(mapping->host, folio->index);
> +	folio_wait_writeback(folio);
>  
>  	if (folio_test_uptodate(folio) || len >= folio_size(folio))
>  		goto success;
> @@ -2497,13 +2233,11 @@ static int fuse_launder_folio(struct folio *folio)
>  {
>  	int err = 0;
>  	if (folio_clear_dirty_for_io(folio)) {
> -		struct inode *inode = folio->mapping->host;
> -
>  		/* Serialize with pending writeback for the same page */
> -		fuse_wait_on_page_writeback(inode, folio->index);
> +		folio_wait_writeback(folio);
>  		err = fuse_writepage_locked(folio);
>  		if (!err)
> -			fuse_wait_on_page_writeback(inode, folio->index);
> +			folio_wait_writeback(folio);
>  	}
>  	return err;
>  }
> @@ -2547,7 +2281,7 @@ static vm_fault_t fuse_page_mkwrite(struct vm_fault *vmf)
>  		return VM_FAULT_NOPAGE;
>  	}
>  
> -	fuse_wait_on_page_writeback(inode, page->index);
> +	folio_wait_writeback(page_folio(page));
>  	return VM_FAULT_LOCKED;
>  }
>  
> @@ -3375,7 +3109,6 @@ void fuse_init_file_inode(struct inode *inode, unsigned int flags)
>  	fi->iocachectr = 0;
>  	init_waitqueue_head(&fi->page_waitq);
>  	init_waitqueue_head(&fi->direct_io_waitq);
> -	fi->writepages = RB_ROOT;
>  
>  	if (IS_ENABLED(CONFIG_FUSE_DAX))
>  		fuse_dax_inode_init(inode, flags);
> -- 
> 2.43.5
>