On Fri, 25 May 2012 15:06:41 +0200 Lukasz Dorau <lukasz.dorau@xxxxxxxxx>
wrote:
> We do not check the return value of sysfs_get_ll() now. It is wrong.
> If reading of the sysfs "degraded" key does not succeed,
> the "new_degraded" variable will not be initiated
> and accidentally it can have the value of "degraded" variable.
> In that case the change of degradation will not be checked.
>
> It happens if mdadm is compiled with gcc's "-fstack-protector" option
> when one tries to stop a volume under reshape (e.g. OLCE).
> Reshape seems to be finished then (metadata is in normal/clean state)
> but it is not finished, it is broken and data are corrupted.
>
> Now we always check the return value of sysfs_get_ll().
> Even if reading of the sysfs "degraded" key does not succeed
> (rv == -1) the change of degradation will be checked.
>
> Signed-off-by: Lukasz Dorau <lukasz.dorau@xxxxxxxxx>
> ---
> super-intel.c | 6 ++++--
> 1 files changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/super-intel.c b/super-intel.c
> index 6c87e20..07ab9ae 100644
> --- a/super-intel.c
> +++ b/super-intel.c
> @@ -10370,8 +10370,10 @@ int check_degradation_change(struct mdinfo *info,
> int degraded)
> {
> unsigned long long new_degraded;
> - sysfs_get_ll(info, NULL, "degraded", &new_degraded);
> - if (new_degraded != (unsigned long long)degraded) {
> + int rv;
> +
> + rv = sysfs_get_ll(info, NULL, "degraded", &new_degraded);
> + if ((rv == -1) || (new_degraded != (unsigned long long)degraded)) {
> /* check each device to ensure it is still working */
> struct mdinfo *sd;
> new_degraded = 0;
applied, thanks.
NeilBrown
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