From aac17948a7ce01fb60b9ee6cf902967a47b3ce26 Mon Sep 17 00:00:00 2001
From: Richard Weinberger <richard@nod.at>
Date: Wed, 17 Jan 2018 19:12:42 +0100
Subject: [PATCH] ubifs: Check ubifs_wbuf_sync() return code
Git-commit: aac17948a7ce01fb60b9ee6cf902967a47b3ce26
Patch-mainline: v4.17-rc1
References: bsc#1052766

If ubifs_wbuf_sync() fails we must not write a master node with the
dirty marker cleared.
Otherwise it is possible that in case of an IO error while syncing we
mark the filesystem as clean and UBIFS refuses to recover upon next
mount.

Cc: <stable@vger.kernel.org>
Fixes: 1e51764a3c2a ("UBIFS: add new flash file system")
Signed-off-by: Richard Weinberger <richard@nod.at>
Acked-by: Jan Kara <jack@suse.cz>

---
 fs/ubifs/super.c | 14 ++++++++++----
 1 file changed, 10 insertions(+), 4 deletions(-)

diff --git a/fs/ubifs/super.c b/fs/ubifs/super.c
index b16ef162344a..6c397a389105 100644
--- a/fs/ubifs/super.c
+++ b/fs/ubifs/super.c
@@ -1737,8 +1737,11 @@ static void ubifs_remount_ro(struct ubifs_info *c)
 
 	dbg_save_space_info(c);
 
-	for (i = 0; i < c->jhead_cnt; i++)
-		ubifs_wbuf_sync(&c->jheads[i].wbuf);
+	for (i = 0; i < c->jhead_cnt; i++) {
+		err = ubifs_wbuf_sync(&c->jheads[i].wbuf);
+		if (err)
+			ubifs_ro_mode(c, err);
+	}
 
 	c->mst_node->flags &= ~cpu_to_le32(UBIFS_MST_DIRTY);
 	c->mst_node->flags |= cpu_to_le32(UBIFS_MST_NO_ORPHS);
@@ -1804,8 +1807,11 @@ static void ubifs_put_super(struct super_block *sb)
 			int err;
 
 			/* Synchronize write-buffers */
-			for (i = 0; i < c->jhead_cnt; i++)
-				ubifs_wbuf_sync(&c->jheads[i].wbuf);
+			for (i = 0; i < c->jhead_cnt; i++) {
+				err = ubifs_wbuf_sync(&c->jheads[i].wbuf);
+				if (err)
+					ubifs_ro_mode(c, err);
+			}
 
 			/*
 			 * We are being cleanly unmounted which means the
-- 
2.13.6