tree c0b00050760fd58d3ebfd624b1ffbfb0ec38df96
parent 6f06f45a18edfcdadaf7364b160d0a97360b2455
author Eric Sandeen <sandeen@redhat.com> 1755885356 -0500
committer Greg Kroah-Hartman <gregkh@linuxfoundation.org> 1756992391 +0200

xfs: do not propagate ENODATA disk errors into xattr code

commit ae668cd567a6a7622bc813ee0bb61c42bed61ba7 upstream.

ENODATA (aka ENOATTR) has a very specific meaning in the xfs xattr code;
namely, that the requested attribute name could not be found.

However, a medium error from disk may also return ENODATA. At best,
this medium error may escape to userspace as "attribute not found"
when in fact it's an IO (disk) error.

At worst, we may oops in xfs_attr_leaf_get() when we do:

	error = xfs_attr_leaf_hasname(args, &bp);
	if (error == -ENOATTR)  {
		xfs_trans_brelse(args->trans, bp);
		return error;
	}

because an ENODATA/ENOATTR error from disk leaves us with a null bp,
and the xfs_trans_brelse will then null-deref it.

As discussed on the list, we really need to modify the lower level
IO functions to trap all disk errors and ensure that we don't let
unique errors like this leak up into higher xfs functions - many
like this should be remapped to EIO.

However, this patch directly addresses a reported bug in the xattr
code, and should be safe to backport to stable kernels. A larger-scope
patch to handle more unique errors at lower levels can follow later.

(Note, prior to 07120f1abdff we did not oops, but we did return the
wrong error code to userspace.)

Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Fixes: 07120f1abdff ("xfs: Add xfs_has_attr and subroutines")
Cc: stable@vger.kernel.org # v5.9+
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Carlos Maiolino <cem@kernel.org>
[ Adjust context: removed metadata health tracking calls ]
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>