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
>
> 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;
> }
>
> --
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