Non-deleted directories (Was Re: reiser4 (ccreg40)...)

[Edward Shishkin <edward.shishkin@gmail.com>]

On 09/11/2014 07:16 PM, Edward Shishkin wrote:
>
> On 09/10/2014 11:39 PM, Ivan Shapovalov wrote:
>

[...]

>>>> 3a. I can reproduce the "directory not empty" bug :) Interestingly, 
>>>> it is
>>>> always the same directory under the aforementioned huge hierarchy. 
>>>> (I've
>>>> done the unpack-remove cycle a few times.)
>>> I've made a conclusion that this is caused by unexpected disappearing
>>> of a record, which represents a directory entry in the directory item
>>> (currently directory items are managed by cde ITEM plugin, aka 
>>> "compound
>>> directory entries"). In the error path (ENOENT) the size of the 
>>> directory is
>>> not decremented, which makes the directory undeletable. I still 
>>> don't know
>>> who kills the entries. Special debugging info is needed to find/fix it.
>> What kind of information is needed?
>
>
> We need to find all places, where the records are created / killed
> and insert a hook, which prints such events for the entry which
> unexpectedly disappears. This will get us a chance to find the culprit.
> I have to say: this is not a big fun...


Ughhh, parse_cut (node40.c) is the culprit.
If region to cut contains objects with non-unique keys (the case of
hash collisions), then this function evaluates the cut mode incorrectly.

I think that this bug has been introduced implicitly ~11 years ago
after the design change in reiser4 (introducing non-unique keys).

I'll provide the fixup later..

Edward.