Re: [PATCH 1/3] FIX: Do not allow for multiple reshape_array() execution during reshape_container() call

[NeilBrown <neilb@suse.de>]

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On Tue, 13 Dec 2011 11:12:10 +0100 Adam Kwolek <adam.kwolek@intel.com> wrote:

> It can happen during reshape restart that reshape_array() can exit without
> error (e.g. Grow.c:1915) and reshape is not moved to next array.
> reshape_array() is called again for the same device.
> Do not allow for such execution and check if last reshaped array is not
> the current one.
> This patch can be treat not as solution, but it allows for such errors
> detection.
> 
> Signed-off-by: Adam Kwolek <adam.kwolek@intel.com>

Hi Adam.
 I'm afraid I understand the problem that requires this patch.
Could you please outline how it can happen that "reshape_array() can exit
without error (e.g. Grow.c:1915) and reshape is not moved to next array."

Also the comment in the code seems to be incomplete.  Could you complete it
please?
Thanks.

The other 2 patches in the series are fine.

Thanks,
NeilBrown

> ---
> 
>  Grow.c |   12 ++++++++++++
>  1 files changed, 12 insertions(+), 0 deletions(-)
> 
> diff --git a/Grow.c b/Grow.c
> index 184a973..1828f83 100644
> --- a/Grow.c
> +++ b/Grow.c
> @@ -2462,6 +2462,7 @@ int reshape_container(char *container, char *devname,
>  {
>  	struct mdinfo *cc = NULL;
>  	int rv = restart;
> +	int last_devnum = -1;
>  
>  	/* component_size is not meaningful for a container,
>  	 * so pass '-1' meaning 'no change'
> @@ -2546,6 +2547,17 @@ int reshape_container(char *container, char *devname,
>  		if (!adev)
>  			adev = content->text_version;
>  
> +		if (last_devnum == mdstat->devnum) {
> +			/* do not allow for reentry reshape_array()
> +			 * for the same device. It can happen when resahpe_array
This one.  Should there be more to this sentence?

NB


> +			 */
> +			printf(Name ": Multiple reshape execution detected for "
> +			       "device  %s.", adev);
> +			close(fd);
> +			break;
> +		}
> +		last_devnum = mdstat->devnum;
> +
>  		sysfs_init(content, fd, mdstat->devnum);
>  
>  		rv = reshape_array(container, fd, adev, st,


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