cifs: Call close synchronously during unlink/rename/lease break.

During unlink/rename/lease break, deferred work for close is
scheduled immediately but in an asynchronous manner which might
lead to race with actual(unlink/rename) commands.

This change will schedule close synchronously which will avoid
the race conditions with other commands.

Signed-off-by: Rohith Surabattula <rohiths@microsoft.com>
Reviewed-by: Shyam Prasad N <sprasad@microsoft.com>
Cc: stable@vger.kernel.org # 5.13
Signed-off-by: Steve French <stfrench@microsoft.com>

1 files changed, 17 insertions, 18 deletions

diff --git a/fs/cifs/file.c b/fs/cifs/file.c
index 0a72840a88f1..bb98fbdd22a9 100644
--- a/fs/cifs/file.c
+++ b/fs/cifs/file.c
@@ -4848,34 +4848,33 @@ void cifs_oplock_break(struct work_struct *work)
 
 oplock_break_ack:
 	/*
-	 * releasing stale oplock after recent reconnect of smb session using
-	 * a now incorrect file handle is not a data integrity issue but do
-	 * not bother sending an oplock release if session to server still is
-	 * disconnected since oplock already released by the server
-	 */
-	if (!cfile->oplock_break_cancelled) {
-		rc = tcon->ses->server->ops->oplock_response(tcon, &cfile->fid,
-							     cinode);
-		cifs_dbg(FYI, "Oplock release rc = %d\n", rc);
-	}
-	/*
 	 * When oplock break is received and there are no active
 	 * file handles but cached, then schedule deferred close immediately.
 	 * So, new open will not use cached handle.
 	 */
 	spin_lock(&CIFS_I(inode)->deferred_lock);
 	is_deferred = cifs_is_deferred_close(cfile, &dclose);
+	spin_unlock(&CIFS_I(inode)->deferred_lock);
 	if (is_deferred &&
 	    cfile->deferred_close_scheduled &&
 	    delayed_work_pending(&cfile->deferred)) {
-		/*
-		 * If there is no pending work, mod_delayed_work queues new work.
-		 * So, Increase the ref count to avoid use-after-free.
-		 */
-		if (!mod_delayed_work(deferredclose_wq, &cfile->deferred, 0))
-			cifsFileInfo_get(cfile);
+		if (cancel_delayed_work(&cfile->deferred)) {
+			_cifsFileInfo_put(cfile, false, false);
+			goto oplock_break_done;
+		}
 	}
-	spin_unlock(&CIFS_I(inode)->deferred_lock);
+	/*
+	 * releasing stale oplock after recent reconnect of smb session using
+	 * a now incorrect file handle is not a data integrity issue but do
+	 * not bother sending an oplock release if session to server still is
+	 * disconnected since oplock already released by the server
+	 */
+	if (!cfile->oplock_break_cancelled) {
+		rc = tcon->ses->server->ops->oplock_response(tcon, &cfile->fid,
+							     cinode);
+		cifs_dbg(FYI, "Oplock release rc = %d\n", rc);
+	}
+oplock_break_done:
 	_cifsFileInfo_put(cfile, false /* do not wait for ourself */, false);
 	cifs_done_oplock_break(cinode);
 }