From 3df32196519d1556b8851b610ca1aa68c5b673d3 Mon Sep 17 00:00:00 2001
From: Dmitry Monakhov <dmonakhov@openvz.org>
Date: Tue, 28 May 2013 13:19:01 +0400
Subject: ext3: Fix fsync error handling after filesystem abort.

If filesystem was aborted we will return success
due to (sb->s_flags & MS_RDONLY) which is incorrect and
results in data loss.
In order to handle fs abort correctly we have to check
fs state once we discover that it is in MS_RDONLY state

Test case: http://patchwork.ozlabs.org/patch/244297/
Changes from V1:
 - fix spelling
 - fix smp_rmb()/debug order

Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org>
Signed-off-by: Jan Kara <jack@suse.cz>
---
 fs/ext3/super.c | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

(limited to 'fs/ext3/super.c')

diff --git a/fs/ext3/super.c b/fs/ext3/super.c
index 6356665a74bb..c47f14750722 100644
--- a/fs/ext3/super.c
+++ b/fs/ext3/super.c
@@ -174,6 +174,11 @@ static void ext3_handle_error(struct super_block *sb)
 	if (test_opt (sb, ERRORS_RO)) {
 		ext3_msg(sb, KERN_CRIT,
 			"error: remounting filesystem read-only");
+		/*
+		 * Make sure updated value of ->s_mount_state will be visible
+		 * before ->s_flags update.
+		 */
+		smp_wmb();
 		sb->s_flags |= MS_RDONLY;
 	}
 	ext3_commit_super(sb, es, 1);
@@ -291,8 +296,14 @@ void ext3_abort(struct super_block *sb, const char *function,
 	ext3_msg(sb, KERN_CRIT,
 		"error: remounting filesystem read-only");
 	EXT3_SB(sb)->s_mount_state |= EXT3_ERROR_FS;
-	sb->s_flags |= MS_RDONLY;
 	set_opt(EXT3_SB(sb)->s_mount_opt, ABORT);
+	/*
+	 * Make sure updated value of ->s_mount_state will be visible
+	 * before ->s_flags update.
+	 */
+	smp_wmb();
+	sb->s_flags |= MS_RDONLY;
+
 	if (EXT3_SB(sb)->s_journal)
 		journal_abort(EXT3_SB(sb)->s_journal, -EIO);
 }
-- 
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