SMB2 and allocation size

[Andreas Schneider]

Hi,

my gitlab runner for MIT KRB5 failed when running the samba3.smb2.session test 
with the following error:

Exception: Exception: ../../source4/torture/smb2/session.c:85: (&io1)-
>out.alloc_size was 1048576 (0x100000), expected 0 (0x0): out.alloc_size 
incorrect

I've tracked it down to a difference in vfswrap_get_alloc_size().

On the docker image an empty file gets 8 blocks:

$ touch foo && stat foo
  File: foo
  Size: 0         	Blocks: 8          IO Block: 4096   regular empty file
Device: 809h/2057d	Inode: 1593246     Links: 1
Access: (0644/-rw-r--r--)  Uid: (    0/    root)   Gid: (    0/    root)
Access: 2018-11-30 11:12:16.000000000 +0000
Modify: 2018-11-30 11:12:16.000000000 +0000
Change: 2018-11-30 11:12:16.000000000 +0000
 Birth: -

Then this is rounded up by smb_roundup() at the end of 
vfswrap_get_alloc_size().



On my system locally with btrfs this is:

$ touch foo && stat foo
  File: foo
  Size: 0               Blocks: 0          IO Block: 4096   regular empty file
Device: fd02h/64770d    Inode: 135018551   Links: 1
Access: (0600/-rw-------)  Uid: ( 1000/     asn)   Gid: ( 1000/     asn)
Access: 2018-11-30 12:19:25.891655519 +0100
Modify: 2018-11-30 12:19:25.891655519 +0100
Change: 2018-11-30 12:19:25.891655519 +0100
 Birth: -


As vfswrap_get_alloc_size() states to handle sparse files, I think this is the 
reason for the roundup. Attached is a patch to address this in the torture 
test. I'm not sure if this should be addressed differently.


Please check the attached file and review it.


Thanks,


	Andreas


-- 
Andreas Schneider                      asn at samba.org
Samba Team                             www.samba.org
GPG-ID:     8DFF53E18F2ABC8D8F3C92237EE0FC4DCC014E3D
-------------- next part --------------
A non-text attachment was scrubbed...
Name: 0001-s4-torture-Check-if-the-size-is-the-SMB-roundup-size.patch
Type: text/x-patch
Size: 1993 bytes
Desc: not available
URL: <http://lists.samba.org/pipermail/samba-technical/attachments/20181130/0a463693/0001-s4-torture-Check-if-the-size-is-the-SMB-roundup-size.bin>