[newlib-cygwin/cygwin-3_5-branch] Cygwin: lockf: Fix adding a new lock over multiple locks

[Takashi Yano]

https://sourceware.org/git/gitweb.cgi?p=newlib-cygwin.git;h=b76735a5719375cf9d33d63612092ff8516e99a0

commit b76735a5719375cf9d33d63612092ff8516e99a0
Author: Takashi Yano <takashi.yano@nifty.ne.jp>
Date:   Sun Oct 20 00:59:51 2024 +0900

    Cygwin: lockf: Fix adding a new lock over multiple locks
    
    Previously, adding a new lock by lockf() over multiple existing locks
    failed. This is due to a bug that lf_setlock() tries to create a lock
    that has already been created. This patch fixes the issue.
    
    Addresses: https://cygwin.com/pipermail/cygwin/2024-October/256528.html
    Fixes: a998dd705576 ("* flock.cc: Implement all advisory file locking here.")
    Reported-by: Christian Franke <Christian.Franke@t-online.de>
    Reviewed-by: Corinna Vinschen <corinna@vinschen.de>
    Signed-off-by: Takashi Yano <takashi.yano@nifty.ne.jp>

Diff:
---
 winsup/cygwin/flock.cc      | 7 ++++---
 winsup/cygwin/release/3.5.5 | 4 ++++
 2 files changed, 8 insertions(+), 3 deletions(-)

diff --git a/winsup/cygwin/flock.cc b/winsup/cygwin/flock.cc
index 0f1efa01d..5550b3a5b 100644
--- a/winsup/cygwin/flock.cc
+++ b/winsup/cygwin/flock.cc
@@ -1454,13 +1454,14 @@ lf_setlock (lockf_t *lock, inode_t *node, lockf_t **clean, HANDLE fhdl)
 	  /*
 	   * Add the new lock before overlap.
 	   */
-	  if (needtolink) {
+	  if (needtolink)
+	    {
 	      *prev = lock;
 	      lock->lf_next = overlap;
-	  }
+	      lock->create_lock_obj ();
+	    }
 	  overlap->lf_start = lock->lf_end + 1;
 	  lf_wakelock (overlap, fhdl);
-	  lock->create_lock_obj ();
 	  overlap->create_lock_obj ();
 	  break;
 	}
diff --git a/winsup/cygwin/release/3.5.5 b/winsup/cygwin/release/3.5.5
index bcc2c661b..ca96edf04 100644
--- a/winsup/cygwin/release/3.5.5
+++ b/winsup/cygwin/release/3.5.5
@@ -12,3 +12,7 @@ Fixes:
   Addresses: https://sourceware.org/pipermail/cygwin/2024-September/256468.html
 
 - Fix timer_delete() return value which always indicated failure.
+
+- Fix lockf() error which occurs when adding a new lock over multiple
+  locks.
+  Addresses: https://cygwin.com/pipermail/cygwin/2024-October/256528.html