NFSD: Initialize struct nfsd4_copy earlier

[ Upstream commit 63fab04cbd0f96191b6e5beedc3b643b01c15889 ]

Ensure the refcount and async_copies fields are initialized early.
cleanup_async_copy() will reference these fields if an error occurs
in nfsd4_copy(). If they are not correctly initialized, at the very
least, a refcount underflow occurs.

Reported-by: Olga Kornievskaia <okorniev@redhat.com>
Fixes: aadc3bbea163 ("NFSD: Limit the number of concurrent async COPY operations")
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Tested-by: Olga Kornievskaia <okorniev@redhat.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/fs/nfsd/nfs4proc.c b/fs/nfsd/nfs4proc.c
index 54f43501fed98b7646ed9d241d6863ba5f82fab5..6267a41092ae32500e12e5efcbc7e75212475059 100644 (file)
--- a/fs/nfsd/nfs4proc.c
+++ b/fs/nfsd/nfs4proc.c
@@ -1787,14 +1787,14 @@ nfsd4_copy(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
                if (!async_copy)
                        goto out_err;
                async_copy->cp_nn = nn;
+               INIT_LIST_HEAD(&async_copy->copies);
+               refcount_set(&async_copy->refcount, 1);
                /* Arbitrary cap on number of pending async copy operations */
                if (atomic_inc_return(&nn->pending_async_copies) >
                                (int)rqstp->rq_pool->sp_nrthreads) {
                        atomic_dec(&nn->pending_async_copies);
                        goto out_err;
                }
-               INIT_LIST_HEAD(&async_copy->copies);
-               refcount_set(&async_copy->refcount, 1);
                async_copy->cp_src = kmalloc(sizeof(*async_copy->cp_src), GFP_KERNEL);
                if (!async_copy->cp_src)
                        goto out_err;