[newlib-cygwin/cygwin-3_4-branch] Cygwin: fsync: Fix EINVAL for block device.

[newlib-cygwin/cygwin-3_4-branch] Cygwin: fsync: Fix EINVAL for block device.

[Takashi Yano]

https://sourceware.org/git/gitweb.cgi?p=newlib-cygwin.git;h=17ad18afc62ceefe01273e4c2fff9114275ab909

commit 17ad18afc62ceefe01273e4c2fff9114275ab909
Author: Takashi Yano <takashi.yano@nifty.ne.jp>
Date:   Sat Jan 21 21:33:03 2023 +0900

    Cygwin: fsync: Fix EINVAL for block device.
    
    The commit af8a7c13b516 has a problem that fsync returns EINVAL for
    block device. This patch treats block devices as a special case.
    https://cygwin.com/pipermail/cygwin/2023-January/252916.html
    
    Fixes: af8a7c13b516 ("Cygwin: fsync: Return EINVAL for special files.")
    Reported-by: Yano Ray <yanorei@hotmail.co.jp>
    Reviewed-by: Corinna Vinschen <corinna@vinschen.de>
    Signed-off-by: Takashi Yano <takashi.yano@nifty.ne.jp>

Diff:
---
 winsup/cygwin/fhandler/base.cc | 3 ++-
 winsup/cygwin/release/3.4.6    | 5 +++++
 2 files changed, 7 insertions(+), 1 deletion(-)

diff --git a/winsup/cygwin/fhandler/base.cc b/winsup/cygwin/fhandler/base.cc
index b2738cf20..9b49ec7b9 100644
--- a/winsup/cygwin/fhandler/base.cc
+++ b/winsup/cygwin/fhandler/base.cc
@@ -1728,7 +1728,8 @@ fhandler_base::utimens (const struct timespec *tvp)
 int
 fhandler_base::fsync ()
 {
-  if (!get_handle () || nohandle () || pc.isspecial ())
+  if (!get_handle () || nohandle ()
+      || (pc.isspecial () && !S_ISBLK (pc.dev.mode ())))
     {
       set_errno (EINVAL);
       return -1;
diff --git a/winsup/cygwin/release/3.4.6 b/winsup/cygwin/release/3.4.6
new file mode 100644
index 000000000..c1476ff46
--- /dev/null
+++ b/winsup/cygwin/release/3.4.6
@@ -0,0 +1,5 @@
+Bug Fixes
+---------
+
+Fix a problem that fsync returns EINVAL for block device.
+Addresses: https://cygwin.com/pipermail/cygwin/2023-January/252916.html