1 files changed, 25 insertions, 16 deletions

diff --git a/drivers/staging/lustre/lustre/llite/file.c b/drivers/staging/lustre/lustre/llite/file.c
index 0accf2867055..2c8df434416c 100644
--- a/drivers/staging/lustre/lustre/llite/file.c
+++ b/drivers/staging/lustre/lustre/llite/file.c
@@ -972,9 +972,11 @@ ll_file_io_generic(const struct lu_env *env, struct vvp_io_args *args,
 {
 	struct ll_inode_info *lli = ll_i2info(file_inode(file));
 	struct ll_file_data  *fd  = LUSTRE_FPRIVATE(file);
+	struct vvp_io *vio = vvp_env_io(env);
 	struct range_lock range;
 	struct cl_io	 *io;
-	ssize_t	       result;
+	ssize_t result = 0;
+	int rc = 0;
 
 	CDEBUG(D_VFSTRACE, "file: %pD, type: %d ppos: %llu, count: %zu\n",
 	       file, iot, *ppos, count);
@@ -1006,16 +1008,15 @@ restart:
 			CDEBUG(D_VFSTRACE, "Range lock [%llu, %llu]\n",
 			       range.rl_node.in_extent.start,
 			       range.rl_node.in_extent.end);
-			result = range_lock(&lli->lli_write_tree,
-					    &range);
-			if (result < 0)
+			rc = range_lock(&lli->lli_write_tree, &range);
+			if (rc < 0)
 				goto out;
 
 			range_locked = true;
 		}
 		down_read(&lli->lli_trunc_sem);
 		ll_cl_add(file, env, io);
-		result = cl_io_loop(env, io);
+		rc = cl_io_loop(env, io);
 		ll_cl_remove(file, env);
 		up_read(&lli->lli_trunc_sem);
 		if (range_locked) {
@@ -1026,24 +1027,26 @@ restart:
 		}
 	} else {
 		/* cl_io_rw_init() handled IO */
-		result = io->ci_result;
+		rc = io->ci_result;
 	}
 
 	if (io->ci_nob > 0) {
 		result = io->ci_nob;
+		count -= io->ci_nob;
 		*ppos = io->u.ci_wr.wr.crw_pos;
+
+		/* prepare IO restart */
+		if (count > 0)
+			args->u.normal.via_iter = vio->vui_iter;
 	}
-	goto out;
 out:
 	cl_io_fini(env, io);
-	/* If any bit been read/written (result != 0), we just return
-	 * short read/write instead of restart io.
-	 */
-	if ((result == 0 || result == -ENODATA) && io->ci_need_restart) {
-		CDEBUG(D_VFSTRACE, "Restart %s on %pD from %lld, count:%zu\n",
+
+	if ((!rc || rc == -ENODATA) && count > 0 && io->ci_need_restart) {
+		CDEBUG(D_VFSTRACE, "%s: restart %s from %lld, count:%zu, result: %zd\n",
+		       file_dentry(file)->d_name.name,
 		       iot == CIT_READ ? "read" : "write",
-		       file, *ppos, count);
-		LASSERTF(io->ci_nob == 0, "%zd\n", io->ci_nob);
+		       *ppos, count, result);
 		goto restart;
 	}
 
@@ -1056,13 +1059,19 @@ out:
 			ll_stats_ops_tally(ll_i2sbi(file_inode(file)),
 					   LPROC_LL_WRITE_BYTES, result);
 			fd->fd_write_failed = false;
-		} else if (result != -ERESTARTSYS) {
+		} else if (!result && !rc) {
+			rc = io->ci_result;
+			if (rc < 0)
+				fd->fd_write_failed = true;
+			else
+				fd->fd_write_failed = false;
+		} else if (rc != -ERESTARTSYS) {
 			fd->fd_write_failed = true;
 		}
 	}
 	CDEBUG(D_VFSTRACE, "iot: %d, result: %zd\n", iot, result);
 
-	return result;
+	return result > 0 ? result : rc;
 }
 
 static ssize_t ll_file_read_iter(struct kiocb *iocb, struct iov_iter *to)