fuse: move initialization of fuse_file to fuse_writepages() instead of in callback

Prior to this change, data->ff is checked and if not initialized then
initialized in the fuse_writepages_fill() callback, which gets called
for every dirty page in the address space mapping.

This logic is better placed in the main fuse_writepages() caller where
data.ff is initialized before walking the dirty pages.

No functional changes added.
Signed-off-by: Joanne Koong <joannelkoong@gmail.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>

fs/fuse/file.c

@@ -2263,13 +2263,6 @@ static int fuse_writepages_fill(struct folio *folio,
 	struct page *tmp_page;
 	int err;
 
-	if (!data->ff) {
-		err = -EIO;
-		data->ff = fuse_write_file_get(fi);
-		if (!data->ff)
-			goto out_unlock;
-	}
-
 	if (wpa && fuse_writepage_need_send(fc, &folio->page, ap, data)) {
 		fuse_writepages_send(data);
 		data->wpa = NULL;
@@ -2348,13 +2341,13 @@ static int fuse_writepages(struct address_space *mapping,
 			   struct writeback_control *wbc)
 {
 	struct inode *inode = mapping->host;
+	struct fuse_inode *fi = get_fuse_inode(inode);
 	struct fuse_conn *fc = get_fuse_conn(inode);
 	struct fuse_fill_wb_data data;
 	int err;
 
-	err = -EIO;
 	if (fuse_is_bad(inode))
-		goto out;
+		return -EIO;
 
 	if (wbc->sync_mode == WB_SYNC_NONE &&
 	    fc->num_background >= fc->congestion_threshold)
@@ -2362,7 +2355,9 @@ static int fuse_writepages(struct address_space *mapping,
 
 	data.inode = inode;
 	data.wpa = NULL;
-	data.ff = NULL;
+	data.ff = fuse_write_file_get(fi);
+	if (!data.ff)
+		return -EIO;
 
 	err = -ENOMEM;
 	data.orig_pages = kcalloc(fc->max_pages,
@@ -2376,11 +2371,10 @@ static int fuse_writepages(struct address_space *mapping,
 		WARN_ON(!data.wpa->ia.ap.num_pages);
 		fuse_writepages_send(&data);
 	}
-	if (data.ff)
-		fuse_file_put(data.ff, false);
 
 	kfree(data.orig_pages);
 out:
+	fuse_file_put(data.ff, false);
 	return err;
 }