Corinna Vinschen wrote: .
No, it's not. There's a major difference between mount points and symlinks, which is, mount points are handled inside the kernel, while symlinks are filesystem objects. Reparse points are very certainly filesystem objects. And bind mounts in Cygwin are handled in the "kernel" as well. We can't add reparse points to the mount table on the fly.
--- Windows Internals V5, p965 A reparse point is a block of up to 16kb of application defined reparse data and a 32-bit repase tag that are stored in the $REPARSE_POINT attribute of a file or directory. Whenever an application creates or deletes a reparse point, NTFS updates the \$Extend\$Reparse metadata file, in which NTFS stores\ entries that identify the file record numbers of files and directories that contain reparse points. Storing the records in a central location enables NTFS to provide interfaces for applications to enumerate all a volumes reparse points, **such** as **mount* *points**. The $Extend$Reparse file uses the general indexing facility of NTFS by collating the file's entries (in an index named $R) by reparse point tags. ----- On p669, mounts are covered -- the bottom paragraph says mount points are reparse points that store a volume name as the reparse data. Theoretically, there should be a cental resource that would enable you to know all the reparse points that are associated with mountpoints that wouldn't have to be added "on the fly", but could be added to /etc/fstab on cygwin-initialization. To further the case for linkd being a type of mount: I created 2 links to C:\Users -- one with linkd, the other with mklink /d: C:\tmp\test>dir Volume in drive C is System Disk Volume Serial Number is E889-68E4 Directory of C:\tmp\test 04/08/2014 10:35 PM <DIR> . 04/08/2014 10:35 PM <DIR> .. 04/08/2014 10:35 PM <SYMLINKD> foo [C:\Users] 04/08/2014 10:33 PM <JUNCTION> Users [C:\Users] ---------- Using the fsutil reparsepoint query we can look at the two objects:
fsutil reparsepoint query foo
Reparse Tag Value : 0xa000000c Tag value: Microsoft Tag value: Name Surrogate Tag value: Symbolic Link Reparse Data Length: 0x00000034 Reparse Data: 0000: 10 00 18 00 00 00 10 00 00 00 00 00 43 00 3a 00 ............C.:. 0010: 5c 00 55 00 73 00 65 00 72 00 73 00 5c 00 3f 00 \.U.s.e.r.s.\.?. 0020: 3f 00 5c 00 43 00 3a 00 5c 00 55 00 73 00 65 00 ?.\.C.:.\.U.s.e. 0030: 72 00 73 00 r.s. ---- Foo is a Symbolic Link. ---
fsutil reparsepoint query Users
Reparse Tag Value : 0xa0000003 Tag value: Microsoft Tag value: Name Surrogate Tag value: Mount Point Substitue Name offset: 0 Substitue Name length: 24 Print Name offset: 26 Print Name Length: 16 Substitute Name: \??\C:\Users Print Name: C:\Users Reparse Data Length: 0x00000034 Reparse Data: 0000: 00 00 18 00 1a 00 10 00 5c 00 3f 00 3f 00 5c 00 ........\.?.?.\. 0010: 43 00 3a 00 5c 00 55 00 73 00 65 00 72 00 73 00 C.:.\.U.s.e.r.s. 0020: 00 00 43 00 3a 00 5c 00 55 00 73 00 65 00 72 00 ..C.:.\.U.s.e.r. 0030: 73 00 00 00 s... ---- But the one created with 'linkd' is called a Mount Point. Does that help clarify the differences between linkd and mountvol vs. reparse points created by 'mklink'? -- Problem reports: http://cygwin.com/problems.html FAQ: http://cygwin.com/faq/ Documentation: http://cygwin.com/docs.html Unsubscribe info: http://cygwin.com/ml/#unsubscribe-simple
