Make remote file locks more robust

* lisp/net/tramp.el (tramp-handle-write-region):
* lisp/net/tramp-adb.el (tramp-adb-handle-write-region):
* lisp/net/tramp-smb.el (tramp-smb-handle-write-region):
* lisp/net/tramp-sshfs.el (tramp-sshfs-handle-write-region):
Make file locks more robust.

* test/lisp/net/tramp-tests.el (tramp-test39-make-lock-file-name):
Rename and extend.

1 files changed, 3 insertions, 3 deletions

diff --git a/lisp/net/tramp-smb.el b/lisp/net/tramp-smb.el
index 4008c25d3af..4e4f5548e20 100644
--- a/lisp/net/tramp-smb.el
+++ b/lisp/net/tramp-smb.el
@@ -1589,14 +1589,14 @@ errors for shares like \"C$/\", which are common in Microsoft Windows."
 		     (format "File %s exists; overwrite anyway? " filename)))))
       (tramp-error v 'file-already-exists filename))
 
-    (let (file-locked
+    (let ((file-locked (eq (file-locked-p lockname) t))
 	  (curbuf (current-buffer))
 	  (tmpfile (tramp-compat-make-temp-file filename)))
 
       ;; Lock file.
       (when (and (not (auto-save-file-name-p (file-name-nondirectory filename)))
 		 (file-remote-p lockname)
-		 (not (eq (file-locked-p lockname) t)))
+		 (not file-locked))
 	(setq file-locked t)
 	;; `lock-file' exists since Emacs 28.1.
 	(tramp-compat-funcall 'lock-file lockname))
@@ -1635,7 +1635,7 @@ errors for shares like \"C$/\", which are common in Microsoft Windows."
 	     (current-time))))
 
       ;; Unlock file.
-      (when (and file-locked (eq (file-locked-p lockname) t))
+      (when file-locked
 	;; `unlock-file' exists since Emacs 28.1.
 	(tramp-compat-funcall 'unlock-file lockname))