linux-kernel - Re: [PATCH 1/4] vfs: ignore error on forced remount

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Message-ID: <87hb5y4gl2.fsf@tucsk.pomaz.szeredi.hu>
Date:	Wed, 03 Aug 2011 18:15:05 +0200
From:	Miklos Szeredi <miklos@...redi.hu>
To:	Christoph Hellwig <hch@...radead.org>
Cc:	viro@...IV.linux.org.uk, linux-fsdevel@...r.kernel.org,
	linux-kernel@...r.kernel.org, jack@...e.cz,
	akpm@...ux-foundation.org, toshi.okajima@...fujitsu.com
Subject: Re: [PATCH 1/4] vfs: ignore error on forced remount

Christoph Hellwig <hch@...radead.org> writes:

> On Wed, Aug 03, 2011 at 12:48:38PM +0200, Miklos Szeredi wrote:
>> From: Miklos Szeredi <mszeredi@...e.cz>
>> 
>> On emergency remount we want to force MS_RDONLY on the super block
>> even if ->remount_fs() failed for some reason.
>
> Eww, dangerous territory.  At the very least we should log something
> in the kernel log for thise case.

Like this?

Thanks,
Miklos
----

Subject: vfs: ignore error on forced remount

From: Miklos Szeredi <mszeredi@...e.cz>

On emergency remount we want to force MS_RDONLY on the super block
even if ->remount_fs() failed for some reason.

Signed-off-by: Miklos Szeredi <mszeredi@...e.cz>
---
 fs/super.c |    9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

Index: linux-2.6/fs/super.c
===================================================================
--- linux-2.6.orig/fs/super.c	2011-08-03 16:54:26.000000000 +0200
+++ linux-2.6/fs/super.c	2011-08-03 17:11:56.000000000 +0200
@@ -727,8 +727,13 @@ int do_remount_sb(struct super_block *sb
 
 	if (sb->s_op->remount_fs) {
 		retval = sb->s_op->remount_fs(sb, &flags, data);
-		if (retval)
-			return retval;
+		if (retval) {
+			if(!force)
+				return retval;
+			/* If forced remount, go ahead despite any errors */
+			WARN(1, "forced remount of a %s fs returned %i\n",
+			     sb->s_type->name, retval);
+		}
 	}
 	sb->s_flags = (sb->s_flags & ~MS_RMT_MASK) | (flags & MS_RMT_MASK);
 
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