[ 3.8.y.z extended stable ] Patch "ext4: fix mount/remount error messages for incompatible mount options" has been added to staging queue

[Kamal Mostafa]

This is a note to let you know that I have just added a patch titled

    ext4: fix mount/remount error messages for incompatible mount options

to the linux-3.8.y-queue branch of the 3.8.y.z extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.8.y-queue

This patch is scheduled to be released in version 3.8.13.7.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.8.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

------

>From 0fd5ac3300f9139816058270d627cc5c61ff4c0b Mon Sep 17 00:00:00 2001
From: Piotr Sarna <p.sarna at partner.samsung.com>
Date: Thu, 8 Aug 2013 23:02:24 -0400
Subject: ext4: fix mount/remount error messages for incompatible mount options

commit 6ae6514b33f941d3386da0dfbe2942766eab1577 upstream.

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

First of all, 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 at partner.samsung.com>
Acked-by: Bartlomiej Zolnierkiewicz <b.zolnierkie at samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park at samsung.com>
Signed-off-by: "Theodore Ts'o" <tytso at mit.edu>
Signed-off-by: Kamal Mostafa <kamal at canonical.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 1e4b5926..b83f75d 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -3440,7 +3440,7 @@ 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))
@@ -4618,6 +4618,21 @@ 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");

--
1.8.1.2