dx_readdir_hash_collision_fix.patch

   1 ext4: Fix ext4_dx_readdir hash collision handling
   2
   3 This fixes a bug where readdir() would return a directory entry twice
   4 if there was a hash collision in an hash tree indexed directory.
   5
   6 Signed-off-by: Eugene Dashevsky <eugene@ibrix.com>
   7 Signed-off-by: Mike Snitzer <msnitzer@ibrix.com>
   8 Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
   9 ---
  10 diff --git a/fs/ext4/dir.c b/fs/ext4/dir.c
  11 index 05346fb..2f95937 100644
  12 --- a/fs/ext4/dir.c
  13 +++ b/fs/ext4/dir.c
  14 @@ -412,7 +412,7 @@ static int call_filldir(struct file * filp, void * dirent,
  15                                 get_dtype(sb, fname->file_type));
  16                 if (error) {
  17                         filp->f_pos = curr_pos;
  18 -                       info->extra_fname = fname->next;
  19 +                       info->extra_fname = fname;
  20                         return error;
  21                 }
  22                 fname = fname->next;
  23 @@ -451,11 +451,21 @@ static int ext4_dx_readdir(struct file * filp,
  24          * If there are any leftover names on the hash collision
  25          * chain, return them first.
  26          */
  27 -       if (info->extra_fname &&
  28 -           call_filldir(filp, dirent, filldir, info->extra_fname))
  29 -               goto finished;
  30 -
  31 -       if (!info->curr_node)
  32 +       if (info->extra_fname) {
  33 +               if (call_filldir(filp, dirent, filldir, info->extra_fname))
  34 +                       goto finished;
  35 +
  36 +               info->extra_fname = NULL;
  37 +               info->curr_node = rb_next(info->curr_node);
  38 +               if (!info->curr_node) {
  39 +                       if (info->next_hash == ~0) {
  40 +                               filp->f_pos = EXT4_HTREE_EOF;
  41 +                               goto finished;
  42 +                       }
  43 +                       info->curr_hash = info->next_hash;
  44 +                       info->curr_minor_hash = 0;
  45 +               }
  46 +       } else if (!info->curr_node)
  47                 info->curr_node = rb_first(&info->root);
  48
  49         while (1) {