On my Windows server I mounted multiple NTFS volumes within the same share and played around until I was able to create directories with the same fileid number. ``` PS C:\SHARE> fsutil file queryFileID SUBDS/foo File ID is 0x00000000000000000001000000000026 PS C:\SHARE> fsutil file queryFileID .\SUBDS3\TESTFOLDER\ File ID is 0x00000000000000000001000000000026 ``` The Linux SMB client then grants these two directories the same devid / inode pair. ``` root@truenas[/tmpcifs]# stat SUBDS/foo File: SUBDS/foo Size: 0 Blocks: 0 IO Block: 1048576 directory Device: 5eh/94d Inode: 281474976710694 Links: 2 Access: (0755/drwxr-xr-x) Uid: ( 0/ root) Gid: ( 0/ root) Access: 2023-03-01 13:13:42.425159200 -0800 Modify: 2023-03-01 13:13:42.425159200 -0800 Change: 2023-03-01 13:13:42.425159200 -0800 Birth: 2023-02-22 10:49:37.331907600 -0800 root@truenas[/tmpcifs]# stat SUBDS3/TESTFOLDER File: SUBDS3/TESTFOLDER Size: 0 Blocks: 0 IO Block: 1048576 directory Device: 5eh/94d Inode: 281474976710694 Links: 2 Access: (0755/drwxr-xr-x) Uid: ( 0/ root) Gid: ( 0/ root) Access: 2023-03-01 12:25:56.283589300 -0800 Modify: 2023-03-01 12:25:56.268165700 -0800 Change: 2023-03-01 12:25:56.268165700 -0800 Birth: 2023-03-01 11:48:09.617084100 -0800 ``` Windows identifies mounted volumes via reparse point: https://learn.microsoft.com/en-us/windows/win32/fileio/determining-whether-a-directory-is-a-volume-mount-point This is also clearly visible in packet captures. Andrew
