Merge tag 'nfsd-6.2-1' of git://git.kernel.org/pub/scm/linux/kernel/git/cel/linux

Pull more nfsd updates from Chuck Lever:
 "This contains a number of crasher fixes that were not ready for the
  initial pull request last week.

  In particular, Jeff's patch attempts to address reference count
  underflows in NFSD's filecache, which have been very difficult to
  track down because there is no reliable reproducer.

  Common failure modes:
      https://bugzilla.kernel.org/show_bug.cgi?id=216691#c11
      https://bugzilla.kernel.org/show_bug.cgi?id=216674#c6
      https://bugzilla.redhat.com/show_bug.cgi?id=2138605

  The race windows were found by inspection and the clean-ups appear
  sensible and pass regression testing, so we include them here in the
  hope that they address the problem. However we remain vigilant because
  we don't have 100% certainty yet that the problem is fully addressed.

  Summary:

   - Address numerous reports of refcount underflows in NFSD's filecache

   - Address a UAF in callback setup error handling

   - Address a UAF during server-to-server copy"

* tag 'nfsd-6.2-1' of git://git.kernel.org/pub/scm/linux/kernel/git/cel/linux:
  NFSD: fix use-after-free in __nfs42_ssc_open()
  nfsd: under NFSv4.1, fix double svc_xprt_put on rpc_create failure
  nfsd: rework refcounting in filecache

1 files changed, 5 insertions, 15 deletions

diff --git a/fs/nfsd/nfs4proc.c b/fs/nfsd/nfs4proc.c
index 73ed32ad23a2..bd880d55f565 100644
--- a/fs/nfsd/nfs4proc.c
+++ b/fs/nfsd/nfs4proc.c
@@ -1461,13 +1461,6 @@ out_err:
 	return status;
 }
 
-static void
-nfsd4_interssc_disconnect(struct vfsmount *ss_mnt)
-{
-	nfs_do_sb_deactive(ss_mnt->mnt_sb);
-	mntput(ss_mnt);
-}
-
 /*
  * Verify COPY destination stateid.
  *
@@ -1570,11 +1563,6 @@ nfsd4_cleanup_inter_ssc(struct vfsmount *ss_mnt, struct file *filp,
 {
 }
 
-static void
-nfsd4_interssc_disconnect(struct vfsmount *ss_mnt)
-{
-}
-
 static struct file *nfs42_ssc_open(struct vfsmount *ss_mnt,
 				   struct nfs_fh *src_fh,
 				   nfs4_stateid *stateid)
@@ -1770,7 +1758,7 @@ static int nfsd4_do_async_copy(void *data)
 			default:
 				nfserr = nfserr_offload_denied;
 			}
-			nfsd4_interssc_disconnect(copy->ss_mnt);
+			/* ss_mnt will be unmounted by the laundromat */
 			goto do_callback;
 		}
 		nfserr = nfsd4_do_copy(copy, filp, copy->nf_dst->nf_file,
@@ -1851,8 +1839,10 @@ out_err:
 	if (async_copy)
 		cleanup_async_copy(async_copy);
 	status = nfserrno(-ENOMEM);
-	if (nfsd4_ssc_is_inter(copy))
-		nfsd4_interssc_disconnect(copy->ss_mnt);
+	/*
+	 * source's vfsmount of inter-copy will be unmounted
+	 * by the laundromat
+	 */
 	goto out;
 }