ext4: correct the start block of counting reserved clusters

commit 40ea983 upstream.

When big allocate feature is enabled, we need to count and update
reserved clusters before removing a delayed only extent_status entry.
{init|count|get}_rsvd() have already done this, but the start block
number of this counting isn't correct in the following case.

  lblk            end
   |               |
   v               v
          -------------------------
          |                       | orig_es
          -------------------------
                   ^              ^
      len1 is 0    |     len2     |

If the start block of the orig_es entry founded is bigger than lblk, we
passed lblk as start block to count_rsvd(), but the length is correct,
finally, the range to be counted is offset. This patch fix this by
passing the start blocks to 'orig_es->lblk + len1'.

Signed-off-by: Zhang Yi <yi.zhang@huawei.com>
Cc: stable@kernel.org
Link: https://lore.kernel.org/r/20230824092619.1327976-2-yi.zhang@huaweicloud.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

fs/ext4/extents_status.c

@@ -1431,8 +1431,8 @@ static int __es_remove_extent(struct inode *inode, ext4_lblk_t lblk,
 			}
 		}
 		if (count_reserved)
-			count_rsvd(inode, lblk, orig_es.es_len - len1 - len2,
-				   &orig_es, &rc);
+			count_rsvd(inode, orig_es.es_lblk + len1,
+				   orig_es.es_len - len1 - len2, &orig_es, &rc);
 		goto out_get_reserved;
 	}