befs: add check for ag_shift in superblock

ag_shift and blocks_per_ag contain the same information in different ways, same as block_shift and block_size do. It is worth checking this two are consistent, but since blocks_per_ag isn't documented as mandatory to use some implementations of befs don't enforce this, so making it non-fatal if they don't match and just having it as a warning. Signed-off-by: Luis de Bethencourt <[email protected]> Signed-off-by: Salah Triki <[email protected]>
DespairFactor · Oct 8, 2016 · bbe1bd0 · bbe1bd0
1 parent d1a8c70
commit bbe1bd0
Showing 1 changed file with 7 additions and 0 deletions.
diff --git a/fs/befs/super.c b/fs/befs/super.c
@@ -103,6 +103,13 @@ befs_check_sb(struct super_block *sb)
  return BEFS_ERR;
  }
 
+
+ /* ag_shift also encodes the same information as blocks_per_ag in a
+ * different way, non-fatal consistency check
+ */
+ if ((1 << befs_sb->ag_shift) != befs_sb->blocks_per_ag)
+ befs_error(sb, "ag_shift disagrees with blocks_per_ag.");
+
  if (befs_sb->log_start != befs_sb->log_end || befs_sb->flags == BEFS_DIRTY) {
  befs_error(sb, "Filesystem not clean! There are blocks in the "
  "journal. You must boot into BeOS and mount this volume "