Re: [PATCH] exfat: fix random stack corruption after get_block

[Yuezhang.Mo@xxxxxxxx]

+                       /*
+                        * No buffer_head is allocated.
+                        * (1) bmap: It's enough to fill bh_result without I/O.
+                        * (2) read: The unwritten part should be filled with 0
+                        *           If a folio does not have any buffers,
+                        *           let's returns -EAGAIN to fallback to
+                        *           per-bh IO like block_read_full_folio().
+                        */
+                       if (!folio_buffers(bh_result->b_folio)) {
+                               err = -EAGAIN;
+                               goto done;
+                       }

bh_result is set as mapped by map_bh(), should we need to clear it if return an error?

+
+                       BUG_ON(size > sb->s_blocksize);

This check is equivalent to the following condition and is not necessary.

                } else if (iblock == valid_blks &&
                           (ei->valid_size & (sb->s_blocksize - 1))) {