get_object_id

[Björn JACKE]

Hi,

while taking a look at a msbackup sniff I found two FSCTLs we do 
not support jet. The applied patch at least adds them to ntioctl.h. :)
The one which should be quite easy to implement is the 
FSCTL_GET_OBJECT_ID, here used by the backup software to find 
hardlinks. The Object ID seems to be nothing more and nothing less 
than a combination of inode (file ID) and volume/filesystem ID (there 
also seems to be something like a domain ID, all zero here, no idea 
what this is). Creating a hardlink on ntfs also results in both files 
having the same OID. The file ID is a 64-bit identifier, so that we 
can easily just write our inode number into it. 128-bit filesystems 
with larger inode numbers are by definition not supported. 
Additionally to the file ID also a volume ID is supplied to make the 
whole identifier unique for the system.

First of all I wonder, how can we get a unique volume/filesystem ID to 
support this feature. Any idea?

Another thing is this: running "fsutil objectid query testbild.bmp" on 
a 2k/XP machine gives me this:

Objektkennung :        30e74d1d4deed911abf0000c293e2926
Anfangsvolumekennung : e4ca1fbd9db65949ac234dc315a0f953
Anfangsobjektkennung : 30e74d1d4deed911abf0000c293e2926
Domänenkennung :       00000000000000000000000000000000

In the sniff made between a w2k and an XP machine (see the sniffed 
packages attached) the file ID ("Objektkennung") starts with 31e7... 
instead of 30e7... A bug in fsutil ?


Bjoern
-------------- next part --------------
Index: include/ntioctl.h
===================================================================
--- include/ntioctl.h	(Revision 8059)
+++ include/ntioctl.h	(Arbeitskopie)
@@ -42,6 +42,7 @@
 #define FSCTL_REQUEST_FILTER_OPLOCK  0x0009008C
 #define FSCTL_FIND_FILES_BY_SID	     0x0009008F
 #define FSCTL_FILESYS_GET_STATISTICS 0x00090090
+#define FSCTL_GET_OBJECT_ID          0x0009009C
 #define FSCTL_SET_REPARSE_POINT      0x000900A4
 #define FSCTL_GET_REPARSE_POINT      0x000900A8
 #define FSCTL_DELETE_REPARSE_POINT   0x000900AC
@@ -53,6 +54,7 @@
 #define FSCTL_WRITE_RAW_ENCRYPTED    0x000900DF
 #define FSCTL_READ_RAW_ENCRYPTED     0x000900E3
 #define FSCTL_SIS_COPYFILE           0x00090100
+#define FSCTL_QUERY_ALLOCATED_RANGES 0x000940CF
 #define FSCTL_SIS_LINK_FILES         0x0009C104
 
 #define FSCTL_GET_SHADOW_COPY_DATA   0x00144064   /* KJC -- Shadow Copy information */
@@ -63,7 +65,6 @@
 #define FSCTL_GET_NTFS_FILE_RECORD
 #define FSCTL_ALLOW_EXTENDED_DASD_IO
 #define FSCTL_RECALL_FILE
-#define FSCTL_QUERY_ALLOCATED_RANGES
 
 #endif
 
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