Handle last-coding-system-used in Tramp for all backends

* lisp/net/tramp.el (tramp-skeleton-write-region):
Handle `last-coding-system-used'.
(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):
Set `coding-system-used'.  (Bug#65022)

* lisp/net/tramp-sh.el (tramp-sh-handle-write-region):
Move `last-coding-system-used' handling to
`tramp-skeleton-write-region'.

lisp/net/tramp-adb.el

@@ -552,6 +552,8 @@ Emacs dired can't find files."
 	  (set-file-modes tmpfile (logior (or (file-modes tmpfile) 0) #o0600)))
 	(let (create-lockfiles)
           (write-region start end tmpfile append 'no-message))
+	;; Now, `last-coding-system-used' has the right value.  Remember it.
+	(setq coding-system-used last-coding-system-used)
 	(with-tramp-progress-reporter
 	    v 3 (format-message
 		 "Moving tmp file `%s' to `%s'" tmpfile filename)

lisp/net/tramp-sh.el

@@ -3446,15 +3446,6 @@ implementation will be used."
 
 	(let* ((modes (tramp-default-file-modes
 		       filename (and (eq mustbenew 'excl) 'nofollow)))
-	       ;; We use this to save the value of
-	       ;; `last-coding-system-used' after writing the tmp
-	       ;; file.  At the end of the function, we set
-	       ;; `last-coding-system-used' to this saved value.  This
-	       ;; way, any intermediary coding systems used while
-	       ;; talking to the remote shell or suchlike won't hose
-	       ;; this variable.  This approach was snarfed from
-	       ;; ange-ftp.el.
-	       coding-system-used
 	       ;; Write region into a tmp file.  This isn't really
 	       ;; needed if we use an encoding function, but currently
 	       ;; we use it always because this makes the logic
@@ -3484,11 +3475,11 @@ implementation will be used."
 	      ((error quit)
 	       (setq tramp-temp-buffer-file-name nil)
 	       (delete-file tmpfile)
-	       (signal (car err) (cdr err))))
+	       (signal (car err) (cdr err)))))
 
-	    ;; Now, `last-coding-system-used' has the right value.
-	    ;; Remember it.
-	    (setq coding-system-used last-coding-system-used))
+	  ;; Now, `last-coding-system-used' has the right value.
+	  ;; Remember it.
+	  (setq coding-system-used last-coding-system-used)
 
 	  ;; The permissions of the temporary file should be set.  If
 	  ;; FILENAME does not exist (eq modes nil) it has been
@@ -3618,11 +3609,7 @@ implementation will be used."
 	       v 'file-error
 	       (concat "Method `%s' should specify both encoding and "
 		       "decoding command or an scp program")
-	       method))))
-
-	  ;; Make `last-coding-system-used' have the right value.
-	  (when coding-system-used
-	    (setq last-coding-system-used coding-system-used)))))))
+	       method)))))))))
 
 (defvar tramp-vc-registered-file-names nil
   "List used to collect file names, which are checked during `vc-registered'.")

lisp/net/tramp-smb.el

@@ -1628,6 +1628,8 @@ VEC or USER, or if there is no home directory, return nil."
       ;; `set-visited-file-modtime' ourselves later on.
       (let (create-lockfiles)
         (write-region start end tmpfile append 'no-message))
+      ;; Now, `last-coding-system-used' has the right value.  Remember it.
+      (setq coding-system-used last-coding-system-used)
 
       (with-tramp-progress-reporter
 	  v 3 (format "Moving tmp file %s to %s" tmpfile filename)

lisp/net/tramp-sshfs.el

@@ -379,7 +379,9 @@ arguments to pass to the OPERATION."
   (tramp-skeleton-write-region start end filename append visit lockname mustbenew
     (let (create-lockfiles)
       (write-region
-       start end (tramp-fuse-local-file-name filename) append 'nomessage))))
+       start end (tramp-fuse-local-file-name filename) append 'nomessage))
+    ;; Now, `last-coding-system-used' has the right value.  Remember it.
+    (setq coding-system-used last-coding-system-used)))
 
 
 ;; File name conversions.

lisp/net/tramp.el

@@ -3719,14 +3719,22 @@ BODY is the backend specific code."
   ;; VISIT, for example `jka-compr-handler'.  We must respect this.
   ;; See Bug#55166.
   `(let* ((filename (expand-file-name ,filename))
-	 (lockname (file-truename (or ,lockname filename)))
-	 (handler (and (stringp ,visit)
-		       (let ((inhibit-file-name-handlers
-			      `(tramp-file-name-handler
-				tramp-crypt-file-name-handler
-				. inhibit-file-name-handlers))
-			     (inhibit-file-name-operation 'write-region))
-			 (find-file-name-handler ,visit 'write-region)))))
+	  (lockname (file-truename (or ,lockname filename)))
+	  (handler (and (stringp ,visit)
+			(let ((inhibit-file-name-handlers
+			       `(tramp-file-name-handler
+				 tramp-crypt-file-name-handler
+				 . inhibit-file-name-handlers))
+			      (inhibit-file-name-operation 'write-region))
+			  (find-file-name-handler ,visit 'write-region))))
+	  ;; We use this to save the value of
+	  ;; `last-coding-system-used' after writing the tmp file.  At
+	  ;; the end of the function, we set `last-coding-system-used'
+	  ;; to this saved value.  This way, any intermediary coding
+	  ;; systems used while talking to the remote shell or
+	  ;; suchlike won't hose this variable.  This approach was
+	  ;; snarfed from ange-ftp.el.
+	  coding-system-used)
      (with-parsed-tramp-file-name filename nil
        (if handler
 	   (progn
@@ -3773,9 +3781,7 @@ BODY is the backend specific code."
 	   ;; likely that it is needed shortly after `write-region'.
 	   (tramp-set-file-property v localname "file-exists-p" t)
 
-	   ;; We must protect `last-coding-system-used', now we have
-	   ;; set it to its correct value.
-	   (let (last-coding-system-used (need-chown t))
+	   (let ((need-chown t))
 	     ;; Set file modification time.
 	     (when (or (eq ,visit t) (stringp ,visit))
 	       (when-let ((file-attr (file-attributes filename 'integer)))
@@ -3794,7 +3800,7 @@ BODY is the backend specific code."
                (tramp-set-file-uid-gid filename uid gid))
 
 	     ;; Set extended attributes.  We ignore possible errors,
-	     ;; because ACL strings could be incompatible.
+	     ;; because ACL strings or SELinux contexts could be incompatible.
 	     (when attributes
 	       (ignore-errors
 		 (set-file-extended-attributes filename attributes)))
@@ -3813,7 +3819,11 @@ BODY is the backend specific code."
 	     (when (and (null noninteractive)
 			(or (eq ,visit t) (string-or-null-p ,visit)))
 	       (tramp-message v 0 "Wrote %s" filename))
-	     (run-hooks 'tramp-handle-write-region-hook)))))))
+	     (run-hooks 'tramp-handle-write-region-hook))))
+
+       ;; Make `last-coding-system-used' have the right value.
+       (when coding-system-used
+	 (setq last-coding-system-used coding-system-used)))))
 
 ;;; Common file name handler functions for different backends:
 
@@ -5420,6 +5430,8 @@ of."
       ;; `set-visited-file-modtime' ourselves later on.
       (let (create-lockfiles)
         (write-region start end tmpfile append 'no-message))
+      ;; Now, `last-coding-system-used' has the right value.  Remember it.
+      (setq coding-system-used last-coding-system-used)
       (condition-case nil
 	  (rename-file tmpfile filename 'ok-if-already-exists)
 	(error