On Tue, 16 Nov 2010, Darrick J. Wong wrote:
> 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 <djwong@xxxxxxxxxx>
> > > ---
> > >
> > > 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;
> > > }
> > >
> > > --
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> > >
> >
> > 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 <djwong@xxxxxxxxxx>
>
> I will make the same change to ext3.
>
> --D
Oh, so you want me to post it as a patch ? Ok, then I'll use the same
comment (hope it is ok).
Thanks!
-Lukas
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