linux-kernel - [PATCH 07/28] ceph: avoid false positive maybe-uninitialized warning

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Date:   Tue, 18 Oct 2016 00:08:54 +0200
From:   Arnd Bergmann <arnd@...db.de>
To:     "Yan, Zheng" <zyan@...hat.com>, Sage Weil <sage@...hat.com>,
        Ilya Dryomov <idryomov@...il.com>
Cc:     Linus Torvalds <torvalds@...ux-foundation.org>,
        linux-kernel@...r.kernel.org, Arnd Bergmann <arnd@...db.de>,
        Michal Hocko <mhocko@...e.com>,
        "Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Nikolay Borisov <n.borisov.lkml@...il.com>,
        ceph-devel@...r.kernel.org
Subject: [PATCH 07/28] ceph: avoid false positive maybe-uninitialized warning

A recent rework removed the initialization of the local 'root'
variable that is returned from ceph_real_mount:

fs/ceph/super.c: In function 'ceph_mount':
fs/ceph/super.c:1016:38: error: 'root' may be used uninitialized in this function [-Werror=maybe-uninitialized]

It's not obvious to me what the correct fix is, so this just
returns the saved root as we did before.

Fixes: ce2728aaa82b ("ceph: avoid accessing / when mounting a subpath")
Signed-off-by: Arnd Bergmann <arnd@...db.de>
Cc: "Yan, Zheng" <zyan@...hat.com>
---
 fs/ceph/super.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/fs/ceph/super.c b/fs/ceph/super.c
index a29ffce..79a4be8 100644
--- a/fs/ceph/super.c
+++ b/fs/ceph/super.c
@@ -821,7 +821,8 @@ static struct dentry *ceph_real_mount(struct ceph_fs_client *fsc)
 	dout("mount start %p\n", fsc);
 	mutex_lock(&fsc->client->mount_mutex);
 
-	if (!fsc->sb->s_root) {
+	root = dget(fsc->sb->s_root);
+	if (!root) {
 		const char *path;
 		err = __ceph_open_session(fsc->client, started);
 		if (err < 0)
-- 
2.9.0