linux-kernel - [PATCH 4.18 069/171] Revert "ceph: fix dentry leak in splice

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Date:   Mon, 19 Nov 2018 17:27:45 +0100
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, "Yan, Zheng" <zyan@...hat.com>,
        Ilya Dryomov <idryomov@...il.com>
Subject: [PATCH 4.18 069/171] Revert "ceph: fix dentry leak in splice_dentry()"

4.18-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Yan, Zheng <zyan@...hat.com>

commit efe328230dc01aa0b1269aad0b5fae73eea4677a upstream.

This reverts commit 8b8f53af1ed9df88a4c0fbfdf3db58f62060edf3.

splice_dentry() is used by three places. For two places, req->r_dentry
is passed to splice_dentry(). In the case of error, req->r_dentry does
not get updated. So splice_dentry() should not drop reference.

Cc: stable@...r.kernel.org # 4.18+
Signed-off-by: "Yan, Zheng" <zyan@...hat.com>
Signed-off-by: Ilya Dryomov <idryomov@...il.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 fs/ceph/inode.c |    8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

--- a/fs/ceph/inode.c
+++ b/fs/ceph/inode.c
@@ -1135,8 +1135,12 @@ static struct dentry *splice_dentry(stru
 	if (IS_ERR(realdn)) {
 		pr_err("splice_dentry error %ld %p inode %p ino %llx.%llx\n",
 		       PTR_ERR(realdn), dn, in, ceph_vinop(in));
-		dput(dn);
-		dn = realdn; /* note realdn contains the error */
+		dn = realdn;
+		/*
+		 * Caller should release 'dn' in the case of error.
+		 * If 'req->r_dentry' is passed to this function,
+		 * caller should leave 'req->r_dentry' untouched.
+		 */
 		goto out;
 	} else if (realdn) {
 		dout("dn %p (%d) spliced with %p (%d) "