From: Adam McCoy <adam@forsedomani.com>
Date: Wed, 13 May 2020 11:53:30 +0000 (+0000)
Subject: cifs: fix leaked reference on requeued write
X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=a48137996063d22ffba77e077425f49873856ca5;p=linux.git

cifs: fix leaked reference on requeued write

Failed async writes that are requeued may not clean up a refcount
on the file, which can result in a leaked open. This scenario arises
very reliably when using persistent handles and a reconnect occurs
while writing.

cifs_writev_requeue only releases the reference if the write fails
(rc != 0). The server->ops->async_writev operation will take its own
reference, so the initial reference can always be released.

Signed-off-by: Adam McCoy <adam@forsedomani.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
CC: Stable <stable@vger.kernel.org>
Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com>
---

diff --git a/fs/cifs/cifssmb.c b/fs/cifs/cifssmb.c
index 182b864b3075b..5014a82391ff9 100644
--- a/fs/cifs/cifssmb.c
+++ b/fs/cifs/cifssmb.c
@@ -2152,8 +2152,8 @@ cifs_writev_requeue(struct cifs_writedata *wdata)
 			}
 		}
 
+		kref_put(&wdata2->refcount, cifs_writedata_release);
 		if (rc) {
-			kref_put(&wdata2->refcount, cifs_writedata_release);
 			if (is_retryable_error(rc))
 				continue;
 			i += nr_pages;