pNFS: Don't clear the layout return info if there are segments to return

In pnfs_clear_layoutreturn_info, ensure that we don't clear the layout
return info if there are new segments queued for return due to, for
instance, a race between a LAYOUTRETURN and a failed I/O attempt.
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

fs/nfs/pnfs.c

@@ -322,9 +322,15 @@ pnfs_set_plh_return_info(struct pnfs_layout_hdr *lo, enum pnfs_iomode iomode,
 static void
 pnfs_clear_layoutreturn_info(struct pnfs_layout_hdr *lo)
 {
+	struct pnfs_layout_segment *lseg;
 	lo->plh_return_iomode = 0;
 	lo->plh_return_seq = 0;
 	clear_bit(NFS_LAYOUT_RETURN_REQUESTED, &lo->plh_flags);
+	list_for_each_entry(lseg, &lo->plh_segs, pls_list) {
+		if (!test_bit(NFS_LSEG_LAYOUTRETURN, &lseg->pls_flags))
+			continue;
+		pnfs_set_plh_return_info(lo, lseg->pls_range.iomode, 0);
+	}
 }
 
 static void pnfs_clear_layoutreturn_waitbit(struct pnfs_layout_hdr *lo)
@@ -367,9 +373,9 @@ pnfs_mark_layout_stateid_invalid(struct pnfs_layout_hdr *lo,
 	struct pnfs_layout_segment *lseg, *next;
 
 	set_bit(NFS_LAYOUT_INVALID_STID, &lo->plh_flags);
-	pnfs_clear_layoutreturn_info(lo);
 	list_for_each_entry_safe(lseg, next, &lo->plh_segs, pls_list)
 		pnfs_clear_lseg_state(lseg, lseg_list);
+	pnfs_clear_layoutreturn_info(lo);
 	pnfs_free_returned_lsegs(lo, lseg_list, &range, 0);
 	if (test_bit(NFS_LAYOUT_RETURN, &lo->plh_flags) &&
 	    !test_and_set_bit(NFS_LAYOUT_RETURN_LOCK, &lo->plh_flags))