Re: [PATCH] fs: bound mount propagation fix

From: Roman Borisov
Date: Wed Apr 20 2011 - 07:49:29 EST


On 04/20/2011 01:04 AM, ext Andrew Morton wrote:
On Fri, 1 Apr 2011 18:48:20 +0400
Roman Borisov<ext-roman.borisov@xxxxxxxxx> wrote:

I think MS_SILENT shouldn't be cleared anywhere. I suppose the bug is in
MS_SHARED options checking. Please see the patch below.

Fixed MS_SHARED, MS_SLAVE, MS_UNBINDABLE option handling;
Existing options check doesn't allow to have any options combinations
because of integer comparison (not bitwise).


(when fixing a bug, please include a *complete* description of that bug
in the changelog. It should include a description of the user-visible
misbehaviour and a description of the coding error).


The vfs code is pretty confusing about whether `type' is supposed to be
a scalar or a bitfield.

flags_to_propagation_type() has that is_power_of-two() check in there
to reject more-than-one-bit-set.


Thanks for comment.
I tested the patch on too old kernel which doesn't contain is_power_of_2 checking in do_change_type.
I'll post patch_v2 recently.

--
Roman
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