From: "Darrick J. Wong" Subject: Re: [PATCH v2] ext4: ext4_fill_super shouldn't return 0 on corruption Date: Tue, 16 Nov 2010 14:55:38 -0800 Message-ID: <20101116225538.GC18195@tux1.beaverton.ibm.com> References: <20101115214831.GA18195@tux1.beaverton.ibm.com> <4CE1AC38.9040201@redhat.com> <20101115230346.GB18195@tux1.beaverton.ibm.com> Reply-To: djwong@us.ibm.com Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Eric Sandeen , "Theodore Ts'o" , "Patrick J. LoPresti" , linux-kernel , linux-ext4 , Mingming Cao To: Lukas Czerner Return-path: Received: from e9.ny.us.ibm.com ([32.97.182.139]:55417 "EHLO e9.ny.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755444Ab0KPWzk (ORCPT ); Tue, 16 Nov 2010 17:55:40 -0500 Content-Disposition: inline In-Reply-To: Sender: linux-ext4-owner@vger.kernel.org List-ID: On Tue, Nov 16, 2010 at 01:56:31PM +0100, Lukas Czerner wrote: > On Mon, 15 Nov 2010, Darrick J. Wong wrote: > > > At the start of ext4_fill_super, ret is set to -EINVAL, and any failure path > > out of that function returns ret. However, the generic_check_addressable > > clause sets ret = 0 (if it passes), which means that a subsequent failure (e.g. > > a group checksum error) returns 0 even though the mount should fail. This > > causes vfs_kern_mount in turn to think that the mount succeeded, leading to an > > oops. > > > > A simple fix is to avoid using ret for the generic_check_addressable check, > > which was last changed in commit 30ca22c70e3ef0a96ff84de69cd7e8561b416cb2. > > > > v2: Return -EFBIG in the error case, per Eric Sandeen's suggestion. > > > > Signed-off-by: Darrick J. Wong > > --- > > > > fs/ext4/super.c | 6 +++--- > > 1 files changed, 3 insertions(+), 3 deletions(-) > > > > diff --git a/fs/ext4/super.c b/fs/ext4/super.c > > index 40131b7..120c034 100644 > > --- a/fs/ext4/super.c > > +++ b/fs/ext4/super.c > > @@ -3257,13 +3257,13 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent) > > * Test whether we have more sectors than will fit in sector_t, > > * and whether the max offset is addressable by the page cache. > > */ > > - ret = generic_check_addressable(sb->s_blocksize_bits, > > - ext4_blocks_count(es)); > > - if (ret) { > > + if (generic_check_addressable(sb->s_blocksize_bits, > > + ext4_blocks_count(es))) { > > ext4_msg(sb, KERN_ERR, "filesystem" > > " too large to mount safely on this system"); > > if (sizeof(sector_t) < 8) > > ext4_msg(sb, KERN_WARNING, "CONFIG_LBDAF not enabled"); > > + ret = -EFBIG; > > goto failed_mount; > > } > > > > -- > > To unsubscribe from this list: send the line "unsubscribe linux-ext4" in > > the body of a message to majordomo@vger.kernel.org > > More majordomo info at http://vger.kernel.org/majordomo-info.html > > > > Hi, > > the untested diff below seems like a more general solution to me, > since it allows to return the actual error from > generic_check_addressable(). It seems to work ok for me, so: Acked-by: Darrick J. Wong I will make the same change to ext3. --D > > Thanks. > > -Lukas > > > diff --git a/fs/ext4/super.c b/fs/ext4/super.c > index 61182fe..3d89b72 100644 > --- a/fs/ext4/super.c > +++ b/fs/ext4/super.c > @@ -3268,13 +3268,14 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent) > * Test whether we have more sectors than will fit in sector_t, > * and whether the max offset is addressable by the page cache. > */ > - ret = generic_check_addressable(sb->s_blocksize_bits, > + err = generic_check_addressable(sb->s_blocksize_bits, > ext4_blocks_count(es)); > - if (ret) { > + if (err) { > ext4_msg(sb, KERN_ERR, "filesystem" > " too large to mount safely on this system"); > if (sizeof(sector_t) < 8) > ext4_msg(sb, KERN_WARNING, "CONFIG_LBDAF not enabled"); > + ret = err; > goto failed_mount; > } > > -- > To unsubscribe from this list: send the line "unsubscribe linux-ext4" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html