Cygwin: open: only fix file attributes when trying to create file

Only try to fix the cached DOS attributes if the caller actually
tried to create the file.  Otherwise the fixup code is called even
in cases where we open the file with minimal query access bits and
NtQueryInformationFile() could fail with STATUS_ACCESS_DENIED and
the new cached DOS attributes are wrong again.

Fixes: 37c49de ("Cygwin: open: only fix up cached DOS file attributes for on-disk files")
Signed-off-by: Corinna Vinschen <[email protected]>

(cherry picked from commit c86c08e0ab41ba8d181876a4bdcfa4cd62264827)

Author: github-cygwin

winsup/cygwin/fhandler/base.cc

@@ -720,9 +720,9 @@ fhandler_base::open (int flags, mode_t mode)
 	goto done;
    }
 
-  if (get_device () == FH_FS)
+  if (get_device () == FH_FS && (flags & O_CREAT))
     {
-      /* Fix up file attributes, they are desperately needed later.
+      /* Fix up file attributes if we just made an attempt to create the file.
 
 	 Originally we only did that in the FILE_CREATED case below, but that's
 	 insufficient:

winsup/cygwin/release/3.6.4

@@ -25,3 +25,6 @@ Fixes:
 - Fix potential crashing a process PID by accessing /proc/PID/maps
   in parallel.
   Addresses: https://cygwin.com/pipermail/cygwin/2025-May/258198.html
+
+- Fix ACL operations on directories.
+  Addresses: https://cygwin.com/pipermail/cygwin/2025-July/258433.html