Re: [PATCH 0/2] vvfat: fix two crashes.

[Programmingkid]

> On May 25, 2021, at 2:05 AM, Vladimir Sementsov-Ogievskiy 
> <vsementsov@virtuozzo.com> wrote:
> 
> 24.05.2021 20:33, Programmingkid wrote:
>>> On May 24, 2021, at 12:56 PM, Vladimir Sementsov-Ogievskiy 
>>> <vsementsov@virtuozzo.com> wrote:
>>> 
>>> 24.05.2021 19:06, Programmingkid wrote:
>>>>> On May 24, 2021, at 11:55 AM, Vladimir Sementsov-Ogievskiy 
>>>>> <vsementsov@virtuozzo.com> wrote:
>>>>> 
>>>>> 24.05.2021 18:41, Programmingkid wrote:
>>>>>>> On May 24, 2021, at 6:12 AM, Vladimir Sementsov-Ogievskiy 
>>>>>>> <vsementsov@virtuozzo.com> wrote:
>>>>>>> 
>>>>>>> Hi!
>>>>>>> 
>>>>>>> As reported by Programmingkid, command
>>>>>>> 
>>>>>>> qemu-system-ppc -usb -device usb-storage,drive=fat16 -drive 
>>>>>>> file=fat:rw:fat-type=16:"<path of a host 
>>>>>>> folder>",id=fat16,format=raw,if=none
>>>>>>> 
>>>>>>> crashes.
>>>>>>> 
>>>>>>> I tested it with qemu-system-x86_64 and it reproduces for me. I even
>>>>>>> kept "<path of a host folder>" as is :).
>>>>>>> 
>>>>>>> So, here are two fixes.
>>>>>>> 
>>>>>>> Vladimir Sementsov-Ogievskiy (2):
>>>>>>>  block/vvfat: child_vvfat_qcow: add .get_parent_aio_context, fix crash
>>>>>>>  block/vvfat: fix vvfat_child_perm crash
>>>>>>> 
>>>>>>> include/block/block.h | 1 +
>>>>>>> block.c               | 4 ++--
>>>>>>> block/vvfat.c         | 8 +++-----
>>>>>>> 3 files changed, 6 insertions(+), 7 deletions(-)
>>>>>>> 
>>>>>>> -- 
>>>>>>> 2.29.2
>>>>>> I applied both of your patches to the most recent git commit today and 
>>>>>> they worked. I was able to share files from the host on the guest.
>>>>>> Thank you.
>>>>>> Reviewed-by: John Arbuckle <programmingkidx@gmail.com>
>>>>> 
>>>>> Thanks for testing! Didn't you mean "Tested-by: "? Or if you both 
>>>>> reviewed and tested, having both marks makes sense.
>>>> Yes, you are right. It should be: Tested-by: John Arbuckle 
>>>> <programmingkidx@gmail.com>
>>>>> 
>>>>> Hmm, also, I think "Reported-by" in first patch should be fixed to your 
>>>>> real name too for consistency.
>>>> That should be fine but it isn't important.
>>>> On a related topic would you know if it is possible to use fat32 instead 
>>>> of fat16 for host folder sharing? I did try replacing the text fat16 with 
>>>> fat32 but it didn't appear to work.
>>> 
>>> No, I don't know..
>>> 
>>> Moreover, my quick look at the code of vvfat, this fixed bug (which is 
>>> obviously not covered by tests), and also status of block/vvfat in 
>>> MAINTAINERS file "Odd Fixes", all this leads to advice "don't use it if 
>>> possible". May be Kevin can add something about it, he is maintainer..
>>> 
>>> Could you use for example NFS or Samba, or sshfs to share folders? Or you 
>>> need exactly to make a host folder available in guest vm as usb drive?
>> I do actually need it for some of my VM's. It makes sharing of folder 
>> between the host and guest so easy.
> 
> Probably virtio-fs is modern way for such thing:
> 
> https://virtio-fs.gitlab.io/

Thank you for this.