queue-5.15/nfsd-only-call-fh_unlock-once-in-nfsd_link.patch

   1 From 325495c4b028a5326191f2ee000299fdec104e2f Mon Sep 17 00:00:00 2001
   2 From: Sasha Levin <sashal@kernel.org>
   3 Date: Tue, 26 Jul 2022 16:45:30 +1000
   4 Subject: NFSD: only call fh_unlock() once in nfsd_link()
   5
   6 From: NeilBrown <neilb@suse.de>
   7
   8 [ Upstream commit e18bcb33bc5b69bccc2b532075aa00bb49cc01c5 ]
   9
  10 On non-error paths, nfsd_link() calls fh_unlock() twice.  This is safe
  11 because fh_unlock() records that the unlock has been done and doesn't
  12 repeat it.
  13 However it makes the code a little confusing and interferes with changes
  14 that are planned for directory locking.
  15
  16 So rearrange the code to ensure fh_unlock() is called exactly once if
  17 fh_lock() was called.
  18
  19 Reviewed-by: Jeff Layton <jlayton@kernel.org>
  20 Signed-off-by: NeilBrown <neilb@suse.de>
  21 Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
  22 ---
  23  fs/nfsd/vfs.c | 19 ++++++++++---------
  24  1 file changed, 10 insertions(+), 9 deletions(-)
  25
  26 diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c
  27 index 4b1304fe718fd..ac716ced1fd5f 100644
  28 --- a/fs/nfsd/vfs.c
  29 +++ b/fs/nfsd/vfs.c
  30 @@ -1542,9 +1542,10 @@ nfsd_link(struct svc_rqst *rqstp, struct svc_fh *ffhp,
  31         dirp = d_inode(ddir);
  32
  33         dnew = lookup_one_len(name, ddir, len);
  34 -       host_err = PTR_ERR(dnew);
  35 -       if (IS_ERR(dnew))
  36 -               goto out_nfserr;
  37 +       if (IS_ERR(dnew)) {
  38 +               err = nfserrno(PTR_ERR(dnew));
  39 +               goto out_unlock;
  40 +       }
  41
  42         dold = tfhp->fh_dentry;
  43
  44 @@ -1563,17 +1564,17 @@ nfsd_link(struct svc_rqst *rqstp, struct svc_fh *ffhp,
  45                 else
  46                         err = nfserrno(host_err);
  47         }
  48 -out_dput:
  49         dput(dnew);
  50 -out_unlock:
  51 -       fh_unlock(ffhp);
  52 +out_drop_write:
  53         fh_drop_write(tfhp);
  54  out:
  55         return err;
  56
  57 -out_nfserr:
  58 -       err = nfserrno(host_err);
  59 -       goto out_unlock;
  60 +out_dput:
  61 +       dput(dnew);
  62 +out_unlock:
  63 +       fh_unlock(ffhp);
  64 +       goto out_drop_write;
  65  }
  66
  67  static void
  68 --
  69 2.43.0
  70