queue-4.9/ceph-ensure-d_name-stability-in-ceph_dentry_hash.patch

   1 From 76a495d666e5043ffc315695f8241f5e94a98849 Mon Sep 17 00:00:00 2001
   2 From: Jeff Layton <jlayton@kernel.org>
   3 Date: Wed, 17 Apr 2019 12:58:28 -0400
   4 Subject: ceph: ensure d_name stability in ceph_dentry_hash()
   5
   6 From: Jeff Layton <jlayton@kernel.org>
   7
   8 commit 76a495d666e5043ffc315695f8241f5e94a98849 upstream.
   9
  10 Take the d_lock here to ensure that d_name doesn't change.
  11
  12 Cc: stable@vger.kernel.org
  13 Signed-off-by: Jeff Layton <jlayton@kernel.org>
  14 Reviewed-by: "Yan, Zheng" <zyan@redhat.com>
  15 Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
  16 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
  17
  18 ---
  19  fs/ceph/dir.c |    6 +++++-
  20  1 file changed, 5 insertions(+), 1 deletion(-)
  21
  22 --- a/fs/ceph/dir.c
  23 +++ b/fs/ceph/dir.c
  24 @@ -1471,6 +1471,7 @@ void ceph_dentry_lru_del(struct dentry *
  25  unsigned ceph_dentry_hash(struct inode *dir, struct dentry *dn)
  26  {
  27         struct ceph_inode_info *dci = ceph_inode(dir);
  28 +       unsigned hash;
  29
  30         switch (dci->i_dir_layout.dl_dir_hash) {
  31         case 0: /* for backward compat */
  32 @@ -1478,8 +1479,11 @@ unsigned ceph_dentry_hash(struct inode *
  33                 return dn->d_name.hash;
  34
  35         default:
  36 -               return ceph_str_hash(dci->i_dir_layout.dl_dir_hash,
  37 +               spin_lock(&dn->d_lock);
  38 +               hash = ceph_str_hash(dci->i_dir_layout.dl_dir_hash,
  39                                      dn->d_name.name, dn->d_name.len);
  40 +               spin_unlock(&dn->d_lock);
  41 +               return hash;
  42         }
  43  }
  44