Re: fstat st_size on open files on Parallels filesystem is wrong

[Jonathan Lennox <lennox@cs.columbia.edu>]

On Monday, November 2 2015, "Corinna Vinschen" wrote to "cygwin@cygwin.com" saying:

> On Nov  2 08:08, Jonathan Lennox wrote:
> > On Monday, November 2 2015, "Corinna Vinschen" wrote to "cygwin@cygwin.com" saying:
> > 
> > > On Nov  2 04:38, Jonathan Lennox wrote:
> > > > Unfortunately, when I do "Run As Administrator" on MinTTY, the Mac drives
> > > > (/cygdrive/z and /cygdrive/y) don't show up. I don't know why that is.  So I
> > > > can't test hard links as administrator.
> > > 
> > > That's a security feature of UAC.  You can change that in the registry.
> > > As administrator:
> > > 
> > >   regtool -d set /HKEY_LOCAL_MACHINE/SOFTWARE/Microsoft/Windows/CurrentVersion/Policies/System/EnableLinkedConnections 1
> > > 
> > > Then reboot.
> > 
> > Didn't work:
> > 
> > $ ls /cygdrive/
> > c  d  e
> > 
> > $ regtool get /HKEY_LOCAL_MACHINE/SOFTWARE/Microsoft/Windows/CurrentVersion/Policies/System/EnableLinkedConnections
> > 
>  ^^^?
> 
> That should print "1"
> 
> EnableLinkedConnections is a DWORD value and should be set to 1.

Yes, sorry, it does print 1. Copy & Paste error.

Given "cyg Simple"'s comment, I guess I need to recreate the mapped drives as
the Administrator user?

> > > I added support for this filesystem (called prlfs in mount output) and
> > > without hardlink support for now.  I uploaded a new developer snapshot
> > > to https://cygwin.com/snapshots/ Please give it a try.
> > 
> > No, still seeing the failure in the snapshot:
> > 
> > $ ./stat-size-test.exe /cygdrive/y/foo ~/foo
> > /cygdrive/y/foo: fstat: st_size=0
> > /cygdrive/y/foo: stat: st_size=12
> > /home/jonathan/foo: fstat: st_size=12
> > /home/jonathan/foo: stat: st_size=12
> 
> Weird.  There should be no FileNetworkOpenInformation call anymore for
> Netapp and the PrlSF filesystem.
> 
> Does Cygwin correctly recognize the FS?  What does `mount' print?  It
> should print `type prlfs'.

$ mount
C:/cygwin64/bin on /usr/bin type ntfs (binary,auto)
C:/cygwin64/lib on /usr/lib type ntfs (binary,auto)
C:/cygwin64 on / type ntfs (binary,auto)
C: on /cygdrive/c type ntfs (binary,posix=0,user,noumount,auto)
D: on /cygdrive/d type iso9660 (binary,posix=0,user,noumount,auto)
E: on /cygdrive/e type iso9660 (binary,posix=0,user,noumount,auto)
U: on /cygdrive/u type prlsf (binary,posix=0,user,noumount,auto)
V: on /cygdrive/v type prlsf (binary,posix=0,user,noumount,auto)
W: on /cygdrive/w type prlsf (binary,posix=0,user,noumount,auto)
X: on /cygdrive/x type prlsf (binary,posix=0,user,noumount,auto)
Y: on /cygdrive/y type prlsf (binary,posix=0,user,noumount,auto)
Z: on /cygdrive/z type prlsf (binary,posix=0,user,noumount,auto)


> Can you please once again call `/usr/lib/csih/getVolInfo.exe Z:' and
> `/usr/lib/csih/getVolInfo.exe Y:' and paste the output here?  I'm not
> quite sure because the original getVolInfo call returned a filesystem
> type of "PrlSF", not "PrlFS" as I had expected.  Cygwin now checks for
> "PrlSF".
> 

$ /usr/lib/csih/getVolInfo.exe /cygdrive/z
Device Type        : 7
Characteristics    : 10
Volume Name        : <Shared Folders>
Serial Number      : 0
Max Filenamelength : 255
Filesystemname     : <PrlSF>
Flags              : 3
  FILE_CASE_SENSITIVE_SEARCH  : TRUE
  FILE_CASE_PRESERVED_NAMES   : TRUE
  FILE_UNICODE_ON_DISK        : FALSE
  FILE_PERSISTENT_ACLS        : FALSE
  FILE_FILE_COMPRESSION       : FALSE
  FILE_VOLUME_QUOTAS          : FALSE
  FILE_SUPPORTS_SPARSE_FILES  : FALSE
  FILE_SUPPORTS_REPARSE_POINTS: FALSE
  FILE_SUPPORTS_REMOTE_STORAGE: FALSE
  FILE_VOLUME_IS_COMPRESSED   : FALSE
  FILE_SUPPORTS_OBJECT_IDS    : FALSE
  FILE_SUPPORTS_ENCRYPTION    : FALSE
  FILE_NAMED_STREAMS          : FALSE
  FILE_READ_ONLY_VOLUME       : FALSE
  FILE_SEQUENTIAL_WRITE_ONCE  : FALSE
  FILE_SUPPORTS_TRANSACTIONS  : FALSE

$ /usr/lib/csih/getVolInfo.exe /cygdrive/y
Device Type        : 7
Characteristics    : 10
Volume Name        : <Shared Folders>
Serial Number      : 0
Max Filenamelength : 255
Filesystemname     : <PrlSF>
Flags              : 3
  FILE_CASE_SENSITIVE_SEARCH  : TRUE
  FILE_CASE_PRESERVED_NAMES   : TRUE
  FILE_UNICODE_ON_DISK        : FALSE
  FILE_PERSISTENT_ACLS        : FALSE
  FILE_FILE_COMPRESSION       : FALSE
  FILE_VOLUME_QUOTAS          : FALSE
  FILE_SUPPORTS_SPARSE_FILES  : FALSE
  FILE_SUPPORTS_REPARSE_POINTS: FALSE
  FILE_SUPPORTS_REMOTE_STORAGE: FALSE
  FILE_VOLUME_IS_COMPRESSED   : FALSE
  FILE_SUPPORTS_OBJECT_IDS    : FALSE
  FILE_SUPPORTS_ENCRYPTION    : FALSE
  FILE_NAMED_STREAMS          : FALSE
  FILE_READ_ONLY_VOLUME       : FALSE
  FILE_SEQUENTIAL_WRITE_ONCE  : FALSE
  FILE_SUPPORTS_TRANSACTIONS  : FALSE

(Note that the literal "/usr/lib/csih/getVolInfo.exe Z:" printed
"NtOpenFile(\??\C:\cygwin64\home\jonathan\Z:) failed, c0000033", so I assume
that's not what you want.)

-- 
Jonathan Lennox
lennox@cs.columbia.edu

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