[Yaffs] Hard Link problem

[Yong Kwan Park]

Hi all,

I had a problem related with hard link in yaffs2.

A problem occured in the following two deleted objects.

yaffs_Object  obj1
      variantType = YAFFS_OBJECT_TYPE_HARDLINK
      objectId = 6036
      variant.hardLinkVariant.equivalentObjectId = 6010
      deleted = 1

yaffs_Object  obj2
       variantType = YAFFS_OBJECT_TYPE_HARDLINK
       objectId = 5816
       variant.hardLinkVariant.equivalentObjectId = 6036
       deleted = 1

An error took place in the function yaffs_ScanBackwards.

Line 4896

case YAFFS_OBJECT_TYPE_HARDLINK:

       in->variant.hardLinkVariant.equivalentObjectId =

             oh->equivalentObjectId;

       in->hardLinks.next =

             (struct list_head *) hardList;

       hardList = in;

       break;



Obj1 was the first object to be executed in the previous code.

Therefore, obj1->hardLinks.next = NULL;

Because hardList was initialized to NULL in line 4432.



This makes an error in the following code.



Line 4953

if (in) {

        /* Add the hardlink pointers */

        hl->variant.hardLinkVariant.equivalentObject = in;

        list_add(&hl->hardLinks, &in->hardLinks);

} else {

        /* Todo Need to report/handle this better.

          * Got a problem... hardlink to a non-existant object

          */

         hl->variant.hardLinkVariant.equivalentObject = NULL;

         INIT_LIST_HEAD(&hl->hardLinks);



}



In line 4956, there is list_add(&hl->hardLinks, &in->hardLinks).

In this case, "in" can be obj1 and "hl" can be obj2.

But obj1->hardLinks.next was initialized to NULL in line 4899.

So NULL pointer is referenced in list_add.



This problem was caused because a deleted hard link referred to

the other deleted hard link.

The other reason is that deleted hard links were set up.



I solved this problem like this.



4897,4901c4897,4904

<                       in->variant.hardLinkVariant.equivalentObjectId =

<                           oh->equivalentObjectId;

<                       in->hardLinks.next =

<                           (struct list_head *) hardList;

<                       hardList = in;

---

>                       if (in->deleted == 0)

>                       {

>                           in->variant.hardLinkVariant.equivalentObjectId =

>                               oh->equivalentObjectId;

>                           in->hardLinks.next =

>                               (struct list_head *) hardList;

>                           hardList = in;

>                       }



Is it necessary to set up hard links about deleted hard links files?
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