gfs2: Fix duplicate should_fault_in_pages() call

In gfs2_file_buffered_write(), we currently jump from the second call of
function should_fault_in_pages() to above the first call, so
should_fault_in_pages() is getting called twice in a row, causing it to
accidentally fall back to single-page writes rather than trying the more
efficient multi-page writes first.

Fix that by moving the retry label to the correct place, behind the
first call to should_fault_in_pages().

Fixes: e1fa9ea ("gfs2: Stop using glock holder auto-demotion for now")
Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>

Author: AstralBob

fs/gfs2/file.c

@@ -1033,8 +1033,8 @@ static ssize_t gfs2_file_buffered_write(struct kiocb *iocb,
 	}
 
 	gfs2_holder_init(ip->i_gl, LM_ST_EXCLUSIVE, 0, gh);
-retry:
 	if (should_fault_in_pages(from, iocb, &prev_count, &window_size)) {
+retry:
 		window_size -= fault_in_iov_iter_readable(from, window_size);
 		if (!window_size) {
 			ret = -EFAULT;