bcachefs: Fix additional misalignment in journal space calculations

Additional fix on top of

f54b2a80d0df bcachefs: Fix misaligned bucket check in journal space calculations

Make sure that when we calculate space for the next entry it's not
misaligned: we need to round_down() to filesystem block size in multiple
places (next entry size calculation as well as total space available).

Reported-by: Ondřej Kraus <[e-mail]>
Signed-off-by: Kent Overstreet <[e-mail]>

fs/bcachefs/journal_reclaim.c

···
 		return (struct journal_space) { 0, 0 };
 
 	/*
+	 * It's possible for bucket size to be misaligned w.r.t. the filesystem
+	 * block size:
+	 */
+	min_bucket_size = round_down(min_bucket_size, block_sectors(c));
+
+	/*
 	 * We sorted largest to smallest, and we want the smallest out of the
 	 * @nr_devs_want largest devices:
 	 */