netfs: Fix netfs_page_mkwrite() to flush conflicting data, not wait

Fix netfs_page_mkwrite() to use filemap_fdatawrite_range(), not
filemap_fdatawait_range() to flush conflicting data.

Fixes: 102a7e2 ("netfs: Allow buffered shared-writeable mmap through netfs_page_mkwrite()")
Signed-off-by: David Howells <dhowells@redhat.com>
Link: https://lore.kernel.org/r/614300.1719228243@warthog.procyon.org.uk
cc: Matthew Wilcox <willy@infradead.org>
cc: Jeff Layton <jlayton@kernel.org>
cc: netfs@lists.linux.dev
cc: v9fs@lists.linux.dev
cc: linux-afs@lists.infradead.org
cc: linux-cifs@vger.kernel.org
cc: linux-mm@kvack.org
cc: linux-fsdevel@vger.kernel.org
Signed-off-by: Christian Brauner <brauner@kernel.org>

Author: dhowells

fs/netfs/buffered_write.c

@@ -555,9 +555,9 @@ vm_fault_t netfs_page_mkwrite(struct vm_fault *vmf, struct netfs_group *netfs_gr
 	group = netfs_folio_group(folio);
 	if (group != netfs_group && group != NETFS_FOLIO_COPY_TO_CACHE) {
 		folio_unlock(folio);
-		err = filemap_fdatawait_range(mapping,
-					      folio_pos(folio),
-					      folio_pos(folio) + folio_size(folio));
+		err = filemap_fdatawrite_range(mapping,
+					       folio_pos(folio),
+					       folio_pos(folio) + folio_size(folio));
 		switch (err) {
 		case 0:
 			ret = VM_FAULT_RETRY;