linux-kernel - [PATCH 2/2] ext4: improve mount/remount error handling

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Message-id: <1375445027-25024-2-git-send-email-p.sarna@partner.samsung.com>
Date:	Fri, 02 Aug 2013 14:03:47 +0200
From:	Piotr Sarna <p.sarna@...tner.samsung.com>
To:	tytso@....edu
Cc:	adilger.kernel@...ger.ca, linux-kernel@...r.kernel.org,
	linux-ext4@...r.kernel.org, b.zolnierkie@...sung.com,
	Piotr Sarna <p.sarna@...tner.samsung.com>,
	Kyungmin Park <kyungmin.park@...sung.com>
Subject: [PATCH 2/2] ext4: improve mount/remount error handling

Commit 5688978 ("ext4: improve handling of conflicting mount options")
introduced incorrect messages shown while choosing wrong mount options.

Firstly, both cases of incorrect mount options, "data=journal,delalloc"
and "data=journal,dioread_nolock" result in the same error message.

Secondly, the problem above isn't solved for remount option: the mismatched
parameter is simply ignored. Moreover, ext4_msg states that remount
with options "data=journal,delalloc" succeeded, which is not true.

To fix it up, I added a simple check after parse_options() call to ensure
that data=journal and delalloc/dioread_nolock parameters are not present
at the same time.

Signed-off-by: Piotr Sarna <p.sarna@...tner.samsung.com>
Acked-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@...sung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@...sung.com>
---
 fs/ext4/super.c |   17 ++++++++++++++++-
 1 file changed, 16 insertions(+), 1 deletion(-)

diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index 10f9bb0..ab0b23b 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -3452,7 +3452,7 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent)
 		}
 		if (test_opt(sb, DIOREAD_NOLOCK)) {
 			ext4_msg(sb, KERN_ERR, "can't mount with "
-				 "both data=journal and delalloc");
+				 "both data=journal and dioread_nolock");
 			goto failed_mount;
 		}
 		if (test_opt(sb, DELALLOC))
@@ -4653,6 +4653,21 @@ static int ext4_remount(struct super_block *sb, int *flags, char *data)
 		goto restore_opts;
 	}
 
+	if (test_opt(sb, DATA_FLAGS) == EXT4_MOUNT_JOURNAL_DATA) {
+		if (test_opt2(sb, EXPLICIT_DELALLOC)) {
+			ext4_msg(sb, KERN_ERR, "can't mount with "
+				 "both data=journal and delalloc");
+			err = -EINVAL;
+			goto restore_opts;
+		}
+		if (test_opt(sb, DIOREAD_NOLOCK)) {
+			ext4_msg(sb, KERN_ERR, "can't mount with "
+				 "both data=journal and dioread_nolock");
+			err = -EINVAL;
+			goto restore_opts;
+		}
+	}
+
 	if (sbi->s_mount_flags & EXT4_MF_FS_ABORTED)
 		ext4_abort(sb, "Abort forced by user");
 
-- 
1.7.9.5

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