From: Lukas Czerner Subject: Re: [PATCH v2] ext4: ext4_fill_super shouldn't return 0 on corruption Date: Tue, 16 Nov 2010 13:56:31 +0100 (CET) Message-ID: References: <20101115214831.GA18195@tux1.beaverton.ibm.com> <4CE1AC38.9040201@redhat.com> <20101115230346.GB18195@tux1.beaverton.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: "Darrick J. Wong" Return-path: Received: from mx1.redhat.com ([209.132.183.28]:64576 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756285Ab0KPM4t (ORCPT ); Tue, 16 Nov 2010 07:56:49 -0500 In-Reply-To: <20101115230346.GB18195@tux1.beaverton.ibm.com> Sender: linux-ext4-owner@vger.kernel.org List-ID: 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(). 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; }