Merge tag 'nfs-for-4.13-2' of git://git.linux-nfs.org/projects/anna/linux-nfs

Pull NFS client bugfixes from Anna Schumaker:
 "Stable bugfix:
   - Fix error reporting regression

  Bugfixes:
   - Fix setting filelayout ds address race
   - Fix subtle access bug when using ACLs
   - Fix setting mnt3_counts array size
   - Fix a couple of pNFS commit races"

* tag 'nfs-for-4.13-2' of git://git.linux-nfs.org/projects/anna/linux-nfs:
  NFS/filelayout: Fix racy setting of fl->dsaddr in filelayout_check_deviceid()
  NFS: Be more careful about mapping file permissions
  NFS: Store the raw NFS access mask in the inode's access cache
  NFSv3: Convert nfs3_proc_access() to use nfs_access_set_mask()
  NFS: Refactor NFS access to kernel access mask calculation
  net/sunrpc/xprt_sock: fix regression in connection error reporting.
  nfs: count correct array for mnt3_counts array size
  Revert commit 722f0b891198 ("pNFS: Don't send COMMITs to the DSes if...")
  pNFS/flexfiles: Handle expired layout segments in ff_layout_initiate_commit()
  NFS: Fix another COMMIT race in pNFS
  NFS: Fix a COMMIT race in pNFS
  mount: copy the port field into the cloned nfs_server structure.
  NFS: Don't run wake_up_bit() when nobody is waiting...
  nfs: add export operations

1 files changed, 11 insertions, 2 deletions

diff --git a/fs/nfs/filelayout/filelayout.c b/fs/nfs/filelayout/filelayout.c
index 080fc6b..44c638b 100644
--- a/fs/nfs/filelayout/filelayout.c
+++ b/fs/nfs/filelayout/filelayout.c
@@ -542,6 +542,10 @@ filelayout_check_deviceid(struct pnfs_layout_hdr *lo,
 	struct nfs4_file_layout_dsaddr *dsaddr;
 	int status = -EINVAL;
 
+	/* Is the deviceid already set? If so, we're good. */
+	if (fl->dsaddr != NULL)
+		return 0;
+
 	/* find and reference the deviceid */
 	d = nfs4_find_get_deviceid(NFS_SERVER(lo->plh_inode), &fl->deviceid,
 			lo->plh_lc_cred, gfp_flags);
@@ -553,8 +557,6 @@ filelayout_check_deviceid(struct pnfs_layout_hdr *lo,
 	if (filelayout_test_devid_unavailable(&dsaddr->id_node))
 		goto out_put;
 
-	fl->dsaddr = dsaddr;
-
 	if (fl->first_stripe_index >= dsaddr->stripe_count) {
 		dprintk("%s Bad first_stripe_index %u\n",
 				__func__, fl->first_stripe_index);
@@ -570,6 +572,13 @@ filelayout_check_deviceid(struct pnfs_layout_hdr *lo,
 		goto out_put;
 	}
 	status = 0;
+
+	/*
+	 * Atomic compare and xchange to ensure we don't scribble
+	 * over a non-NULL pointer.
+	 */
+	if (cmpxchg(&fl->dsaddr, NULL, dsaddr) != NULL)
+		goto out_put;
 out:
 	return status;
 out_put: