Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
From:   Stephen Brennan <stephen.s.brennan@oracle.com>
To:     Alexander Viro <viro@zeniv.linux.org.uk>
Cc:     Stephen Brennan <stephen.s.brennan@oracle.com>,
        linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH 2/3] namei: Standardize callers of filename_lookup()
Date:   Wed,  1 Sep 2021 10:51:42 -0700
Message-Id: <20210901175144.121048-3-stephen.s.brennan@oracle.com>
In-Reply-To: <20210901175144.121048-1-stephen.s.brennan@oracle.com>
References: <20210901175144.121048-1-stephen.s.brennan@oracle.com>
Content-Transfer-Encoding: 8bit
Content-Type: text/plain
MIME-Version: 1.0
X-MS-Exchange-MessageSentRepresentingType: 1
Received: from localhost (148.87.23.10) by SJ0PR05CA0131.namprd05.prod.outlook.com (2603:10b6:a03:33d::16) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.4478.11 via Frontend Transport; Wed, 1 Sep 2021 17:51:50 +0000
X-MS-PublicTrafficType: Email
X-MS-Office365-Filtering-Correlation-Id: 0e585880-2035-432d-5dbd-08d96d712d3f
X-MS-TrafficTypeDiagnostic: CH2PR10MB3863:
X-MS-Exchange-Transport-Forked: True
X-Microsoft-Antispam-PRVS: <CH2PR10MB386321F44049CEFD85D5A110DBCD9@CH2PR10MB3863.namprd10.prod.outlook.com>
X-MS-Oob-TLC-OOBClassifiers: OLM:3968;
X-MS-Exchange-SenderADCheck: 1
X-MS-Exchange-AntiSpam-Relay: 0
X-Microsoft-Antispam: BCL:0;
X-Microsoft-Antispam-Message-Info: =?us-ascii?Q?8unfbx/Tg6vStpT2nT6UqK/0dnbYoAKfBjnxPEWylze6EahTMcGOhIBlNkf+?=
 =?us-ascii?Q?UMfIqSB5BP234z33B2E7kHKz9c9j1syGS/xpjGRGnYPLfsJrjIn5V9LL7Qs6?=
 =?us-ascii?Q?30mLYiRukY2+KJOIthBypNE8Skd6uTrIWZKrZ1V/6biwNfWpVZugCOkT1Kd/?=
 =?us-ascii?Q?vWW62R7AsRB1trq0JQ72lVjUjfuIXjc/OILoHrLv4iKUvmqH+2uebmRhOOm1?=
 =?us-ascii?Q?kTzLnZYn2mk5yNe3FADc/EGU92V56yGLdEmFndo0ypOxuaUV2XRbdTQtp8mt?=
 =?us-ascii?Q?Mg+VEQnihBNlVfZoreb3p4jdn4lbAJXNJneiky2idQdp7/vO11nYIIm3f0ya?=
 =?us-ascii?Q?y4cmUNGXkV+j1Gwss146Z7XJ/o1Ykqg3DZOiBxngpKlciBEaceh1Dm+J+Mn3?=
 =?us-ascii?Q?FqeGQxVLQgLNdXrDhWToD3hVWBMusPXb/KtX3RBpOPLVDojXox+r084Faobo?=
 =?us-ascii?Q?z5Nw7Ofhr2HnirDVyhADpQP0XPS+OUS8DWNyh0Pa1xUguiRoGaQp0InRc5sb?=
 =?us-ascii?Q?UTzUE+QJjrpDXFd9RMwOvdK1Lys0tjsozf6zs3dQ5ER9i/QO2Mh9kd/iTMP/?=
 =?us-ascii?Q?xJ5oJEvKhug+OAdvobanQy/AeKmp0xD9tYjGbd9SuO8YCknau5udK/aywS5z?=
 =?us-ascii?Q?sAnCGKftM1pyU3q5SPJmZ0Dwrim1j07TW7zuzveCif+lIysEdzhsVwRYfJuk?=
 =?us-ascii?Q?zZNa+5g6rU8FUxxPgupGgVwPseVTxhgPhMwVIMJ6i4KNXIr06hTNpLUfriAc?=
 =?us-ascii?Q?HnhD6bJMlQ1R6b2Z97+/BCT7ASHLbleljNZ++4NYEtyjQr9kmg9BN80ATwJw?=
 =?us-ascii?Q?ZHN6d+TGin4LuhlgC/+CrjL4iNRL7YLmOszOQ+vgNsdeU171E9ijeQNFKcM6?=
 =?us-ascii?Q?XkhwGD48TB57vSKMU6vos6FMC6xv2Hfm9MhzDSCBVx0i5BTrI2DXIBJlCRTd?=
 =?us-ascii?Q?0beD/BIGzdCIrznpVa1fjX2ODnOHimMjvOXLFUNn9x1ebKlaq6tICxhvRJbz?=
 =?us-ascii?Q?L1IU3gb0EMe35boeSh/U+KvZ4PiV0uvZX06bUirFcQES7rwkZhsAPW2tb9eQ?=
 =?us-ascii?Q?BzeVxVE4a++iPSszieMtyNCk+TL2jsUYQWNeVOzYq7oAup61k8g=3D?=
X-Forefront-Antispam-Report: CIP:255.255.255.255;CTRY:;LANG:en;SCL:5;SRV:;IPV:NLI;SFV:SPM;H:CH2PR10MB4166.namprd10.prod.outlook.com;PTR:;CAT:OSPM;SFS:(39860400002)(136003)(376002)(346002)(366004)(396003)(5660300002)(316002)(4326008)(38350700002)(38100700002)(6486002)(66946007)(66476007)(66556008)(83380400001)(86362001)(8936002)(478600001)(36756003)(103116003)(8676002)(6666004)(6496006)(2906002)(52116002)(2616005)(956004)(966005)(26005)(1076003)(186003)(6916009)(23200700001);DIR:OUT;SFP:1501;
X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1
X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?ZE2Se5kMwYomcGABi7zNvJY8f6RkSdbZusE7mtRjQAjtzEHsRkHRMzVFJeJM?=
 =?us-ascii?Q?aBdLhamQxyhslyTnMWkAeQ8pKWcb5CxxJiGBJMceq7etf6yN/aYOXnh6Xqco?=
 =?us-ascii?Q?IskOwQdaP8K/wTWwlhLv337cEemfNR4qZaQb9MajQ3N1GSA3UMs76H3Tw6EJ?=
 =?us-ascii?Q?FnORLPXwuVENtdABVjzRukHRanPfoR4lU2HWLUQIckRcAnoDxzjpeX8ZvptC?=
 =?us-ascii?Q?D3j9KQ6Pj7TpxFzWfjM8LvfrNSE+kgneEJnahcCCtkFzW5xZnsLT9hgfjICl?=
 =?us-ascii?Q?0gcWGjUEkRUnXd6IilmDkSEy40U90twObRV++TZt/h7bW6zNXRIL+mpWGyRr?=
 =?us-ascii?Q?9KcatquMOk8K0c0rfrwdhdzioL43sKdYfQMN5zUMKLbmEyCC/J/3AMvhBP2n?=
 =?us-ascii?Q?11NKze5akjelb2zqWv/KXu9Q2IMgm1AEXbfWJyZ/kfg5x0CrOw4oZyt/ShIA?=
 =?us-ascii?Q?orNMO953ar9VXCy8s6y6mEyFSfrxk+v5ctcOEGA7eeDuvvh1TKPPQIJWN+vV?=
 =?us-ascii?Q?ZwEsgBIGeS/fq/fs/qH9j5ielOXrDCdMs6/kbAN0skktYhLDefPJtKZ3tKwu?=
 =?us-ascii?Q?wqyfTjGpIYGQIbhM1WA7gkDNUTrBIFP8dFDJMHam0S73KiW+yp6Jw3G3fe58?=
 =?us-ascii?Q?HVKDL4gGZIl/LoiiwjmPQyRZF5e+Weai74nn4Z6Q66Lnn1NtB/L1zxhQAa1Q?=
 =?us-ascii?Q?TRdFrnz9Atddi8kLSs6OLGH8ChzkV6WbdcLh2O9qTCcGk3PWwi3JKBOlbyIa?=
 =?us-ascii?Q?hjVPCBQmwv/gehBW9bJVRiWwSz4dlE90eBN3rvO8vRJsf2Z2KdXolVr7veX5?=
 =?us-ascii?Q?DxhbCGv2tUYAAhp5EF+tC8XiWy8Wi4X1u6qyK3ft/LtJ95g2QHWhhPzMyBjl?=
 =?us-ascii?Q?eUNDU0H1H2kPM/uJnGp4e0UCLVxiVmKsy0W+LHcR89X1zfCIKon+Tjqt1lB2?=
 =?us-ascii?Q?vPY2wOIvsMKjN5oBf6sYsjbdAvjQ4eFYjd/4eILx34DaPnih923mKti4KM1D?=
 =?us-ascii?Q?G1Ia2ipnhUQqwB3DR/mR1pN0d4nRdSArMZ0GUiS6/8f+JEIItO+gOgZWMZ3I?=
 =?us-ascii?Q?uh3XoV4clL5FqtAn/zR66qYjqn0Bj7ocajwg/fRJffHvD0BbinK38ZM4LGb+?=
 =?us-ascii?Q?HRaOjWyz0j+qe65nNKQ2+GmtUfR907xQQN7SnNyjWIaTXzpY4zEV0mck2h6e?=
 =?us-ascii?Q?Eak/O254twMLiK6iSeSa9zbMqdzmx+97MwM7lJ/7PglIiRC10CMp7TzmPgXr?=
 =?us-ascii?Q?7zFf1Ndv2lOBuYCViVGw/KUAKjBRL3JWK9sb2b51IAe+pD6ng03tDetMIIBB?=
 =?us-ascii?Q?3U67q02PhRzVlFgcOyNTRXaz?=
X-OriginatorOrg: oracle.com
X-MS-Exchange-CrossTenant-Network-Message-Id: 0e585880-2035-432d-5dbd-08d96d712d3f
X-MS-Exchange-CrossTenant-AuthSource: CH2PR10MB4166.namprd10.prod.outlook.com
X-MS-Exchange-CrossTenant-AuthAs: Internal
X-MS-Exchange-CrossTenant-OriginalArrivalTime: 01 Sep 2021 17:51:50.9108
 (UTC)
X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted
X-MS-Exchange-CrossTenant-Id: 4e2c6054-71cb-48f1-bd6c-3a9705aca71b
X-MS-Exchange-CrossTenant-MailboxType: HOSTED
X-MS-Exchange-CrossTenant-UserPrincipalName: uMEqJlN1+ay8OyIkKFJxfM7q99oRMJDa6tjzI/QXSjjkkX8hVguZbVs6hnK2ybGW2K0QK+CPl/HXw1mqc4mEk3Oq3ifLlWND/C2P6NudLCc=
X-MS-Exchange-Transport-CrossTenantHeadersStamped: CH2PR10MB3863
X-Proofpoint-Virus-Version: vendor=nai engine=6300 definitions=10094 signatures=668682
X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 adultscore=0 bulkscore=0 malwarescore=0
 mlxlogscore=999 spamscore=0 phishscore=0 mlxscore=0 suspectscore=0
 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2108310000
 definitions=main-2109010102
X-Proofpoint-GUID: ErR0MIJ2nm1L5iDevcl87oEb5oeeK_Fz
X-Proofpoint-ORIG-GUID: ErR0MIJ2nm1L5iDevcl87oEb5oeeK_Fz
Precedence: bulk
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

filename_lookup() has two variants, one which drops the caller's
reference to filename (filename_lookup), and one which does
not (__filename_lookup). This can be confusing as it's unusual to drop a
caller's reference. Remove filename_lookup, rename __filename_lookup
to filename_lookup, and convert all callers. The cost is a few slightly
longer functions, but the clarity is greater.

Link: https://lore.kernel.org/linux-fsdevel/YS+dstZ3xfcLxhoB@zeniv-ca.linux.org.uk/
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Stephen Brennan <stephen.s.brennan@oracle.com>
---
 fs/fs_parser.c |  1 -
 fs/namei.c     | 41 ++++++++++++++++++++++++-----------------
 2 files changed, 24 insertions(+), 18 deletions(-)

diff --git a/fs/fs_parser.c b/fs/fs_parser.c
index 980d44fd3a36..3df07c0e32b3 100644
--- a/fs/fs_parser.c
+++ b/fs/fs_parser.c
@@ -165,7 +165,6 @@ int fs_lookup_param(struct fs_context *fc,
 		return invalf(fc, "%s: not usable as path", param->key);
 	}
 
-	f->refcnt++; /* filename_lookup() drops our ref. */
 	ret = filename_lookup(param->dirfd, f, flags, _path, NULL);
 	if (ret < 0) {
 		errorf(fc, "%s: Lookup failure for '%s'", param->key, f->name);
diff --git a/fs/namei.c b/fs/namei.c
index f2af301cc79f..76871b7f127a 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -2467,7 +2467,7 @@ static int path_lookupat(struct nameidata *nd, unsigned flags, struct path *path
 	return err;
 }
 
-static int __filename_lookup(int dfd, struct filename *name, unsigned flags,
+int filename_lookup(int dfd, struct filename *name, unsigned flags,
 		    struct path *path, struct path *root)
 {
 	int retval;
@@ -2488,15 +2488,6 @@ static int __filename_lookup(int dfd, struct filename *name, unsigned flags,
 	return retval;
 }
 
-int filename_lookup(int dfd, struct filename *name, unsigned flags,
-		    struct path *path, struct path *root)
-{
-	int retval = __filename_lookup(dfd, name, flags, path, root);
-
-	putname(name);
-	return retval;
-}
-
 /* Returns 0 and nd will be valid on success; Retuns error, otherwise. */
 static int path_parentat(struct nameidata *nd, unsigned flags,
 				struct path *parent)
@@ -2571,8 +2562,14 @@ struct dentry *kern_path_locked(const char *name, struct path *path)
 
 int kern_path(const char *name, unsigned int flags, struct path *path)
 {
-	return filename_lookup(AT_FDCWD, getname_kernel(name),
-			       flags, path, NULL);
+	struct filename *filename;
+	int ret;
+
+	filename = getname_kernel(name);
+	ret = filename_lookup(AT_FDCWD, filename, flags, path, NULL);
+	putname(filename);
+	return ret;
+
 }
 EXPORT_SYMBOL(kern_path);
 
@@ -2588,10 +2585,15 @@ int vfs_path_lookup(struct dentry *dentry, struct vfsmount *mnt,
 		    const char *name, unsigned int flags,
 		    struct path *path)
 {
+	struct filename *filename;
 	struct path root = {.mnt = mnt, .dentry = dentry};
+	int ret;
+
+	filename = getname_kernel(name);
 	/* the first argument of filename_lookup() is ignored with root */
-	return filename_lookup(AT_FDCWD, getname_kernel(name),
-			       flags , path, &root);
+	ret = filename_lookup(AT_FDCWD, filename, flags, path, &root);
+	putname(filename);
+	return ret;
 }
 EXPORT_SYMBOL(vfs_path_lookup);
 
@@ -2795,8 +2797,13 @@ int path_pts(struct path *path)
 int user_path_at_empty(int dfd, const char __user *name, unsigned flags,
 		 struct path *path, int *empty)
 {
-	return filename_lookup(dfd, getname_flags(name, flags, empty),
-			       flags, path, NULL);
+	struct filename *filename;
+	int ret;
+
+	filename = getname_flags(name, flags, empty);
+	ret = filename_lookup(dfd, filename, flags, path, NULL);
+	putname(filename);
+	return ret;
 }
 EXPORT_SYMBOL(user_path_at_empty);
 
@@ -4421,7 +4428,7 @@ int do_linkat(int olddfd, struct filename *old, int newdfd,
 	if (flags & AT_SYMLINK_FOLLOW)
 		how |= LOOKUP_FOLLOW;
 retry:
-	error = __filename_lookup(olddfd, old, how, &old_path, NULL);
+	error = filename_lookup(olddfd, old, how, &old_path, NULL);
 	if (error)
 		goto out_putnames;
 
-- 
2.30.2