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From: Adam McCoy <adam@forsedomani.com>
To: linux-cifs@vger.kernel.org
Cc: Adam McCoy <adam@forsedomani.com>
Subject: [PATCH] cifs: fix leaked reference on requeued write
Date: Wed, 13 May 2020 11:53:30 +0000	[thread overview]
Message-ID: <20200513115330.5187-1-adam@forsedomani.com> (raw)

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>
---
 fs/cifs/cifssmb.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/cifs/cifssmb.c b/fs/cifs/cifssmb.c
index 182b864b3075..5014a82391ff 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;
-- 
2.17.1


             reply	other threads:[~2020-05-13 11:54 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-05-13 11:53 Adam McCoy [this message]
2020-05-13 19:14 ` [PATCH] cifs: fix leaked reference on requeued write Steve French
2020-05-13 21:04   ` Steve French
2020-05-14  1:17     ` Adam McCoy
2020-05-14 22:13       ` Pavel Shilovsky

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