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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org,
        Aliaksei Karaliou <akaraliou.dev@gmail.com>,
        "Darrick J. Wong" <darrick.wong@oracle.com>,
        Sasha Levin <alexander.levin@microsoft.com>
Subject: [PATCH 4.4 21/34] xfs: quota: check result of register_shrinker()
Date:   Fri,  2 Mar 2018 09:51:17 +0100
Message-Id: <20180302084437.376910757@linuxfoundation.org>
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4.4-stable review patch.  If anyone has any objections, please let me know.

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

From: Aliaksei Karaliou <akaraliou.dev@gmail.com>


[ Upstream commit 3a3882ff26fbdbaf5f7e13f6a0bccfbf7121041d ]

xfs_qm_init_quotainfo() does not check result of register_shrinker()
which was tagged as __must_check recently, reported by sparse.

Signed-off-by: Aliaksei Karaliou <akaraliou.dev@gmail.com>
[darrick: move xfs_qm_destroy_quotainos nearer xfs_qm_init_quotainos]
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>

Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 fs/xfs/xfs_qm.c |   45 +++++++++++++++++++++++++++++----------------
 1 file changed, 29 insertions(+), 16 deletions(-)

--- a/fs/xfs/xfs_qm.c
+++ b/fs/xfs/xfs_qm.c
@@ -47,7 +47,7 @@
 STATIC int	xfs_qm_init_quotainos(xfs_mount_t *);
 STATIC int	xfs_qm_init_quotainfo(xfs_mount_t *);
 
-
+STATIC void	xfs_qm_destroy_quotainos(xfs_quotainfo_t *qi);
 STATIC void	xfs_qm_dqfree_one(struct xfs_dquot *dqp);
 /*
  * We use the batch lookup interface to iterate over the dquots as it
@@ -660,9 +660,17 @@ xfs_qm_init_quotainfo(
 	qinf->qi_shrinker.scan_objects = xfs_qm_shrink_scan;
 	qinf->qi_shrinker.seeks = DEFAULT_SEEKS;
 	qinf->qi_shrinker.flags = SHRINKER_NUMA_AWARE;
-	register_shrinker(&qinf->qi_shrinker);
+
+	error = register_shrinker(&qinf->qi_shrinker);
+	if (error)
+		goto out_free_inos;
+
 	return 0;
 
+out_free_inos:
+	mutex_destroy(&qinf->qi_quotaofflock);
+	mutex_destroy(&qinf->qi_tree_lock);
+	xfs_qm_destroy_quotainos(qinf);
 out_free_lru:
 	list_lru_destroy(&qinf->qi_lru);
 out_free_qinf:
@@ -671,7 +679,6 @@ out_free_qinf:
 	return error;
 }
 
-
 /*
  * Gets called when unmounting a filesystem or when all quotas get
  * turned off.
@@ -688,19 +695,7 @@ xfs_qm_destroy_quotainfo(
 
 	unregister_shrinker(&qi->qi_shrinker);
 	list_lru_destroy(&qi->qi_lru);
-
-	if (qi->qi_uquotaip) {
-		IRELE(qi->qi_uquotaip);
-		qi->qi_uquotaip = NULL; /* paranoia */
-	}
-	if (qi->qi_gquotaip) {
-		IRELE(qi->qi_gquotaip);
-		qi->qi_gquotaip = NULL;
-	}
-	if (qi->qi_pquotaip) {
-		IRELE(qi->qi_pquotaip);
-		qi->qi_pquotaip = NULL;
-	}
+	xfs_qm_destroy_quotainos(qi);
 	mutex_destroy(&qi->qi_tree_lock);
 	mutex_destroy(&qi->qi_quotaofflock);
 	kmem_free(qi);
@@ -1563,6 +1558,24 @@ error_rele:
 }
 
 STATIC void
+xfs_qm_destroy_quotainos(
+	xfs_quotainfo_t	*qi)
+{
+	if (qi->qi_uquotaip) {
+		IRELE(qi->qi_uquotaip);
+		qi->qi_uquotaip = NULL; /* paranoia */
+	}
+	if (qi->qi_gquotaip) {
+		IRELE(qi->qi_gquotaip);
+		qi->qi_gquotaip = NULL;
+	}
+	if (qi->qi_pquotaip) {
+		IRELE(qi->qi_pquotaip);
+		qi->qi_pquotaip = NULL;
+	}
+}
+
+STATIC void
 xfs_qm_dqfree_one(
 	struct xfs_dquot	*dqp)
 {