4.4-stable review patch. If anyone has any objections, please let me know.
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From: Shaohua Li shli@fb.com
[ Upstream commit d595567dc4f0c1d90685ec1e2e296e2cad2643ac ]
If we change the number of array's device after device is removed from array, then add the device back to array, we can see that device is added as active role instead of spare which we expected.
Please see the below link for details: https://marc.info/?l=linux-raid&m=153736982015076&w=2
This is caused by that we prefer to use device's previous role which is recorded by saved_raid_disk, but we should respect the new number of conf->raid_disks since it could be changed after device is removed.
Reported-by: Gioh Kim gi-oh.kim@profitbricks.com Tested-by: Gioh Kim gi-oh.kim@profitbricks.com Acked-by: Guoqing Jiang gqjiang@suse.com Signed-off-by: Shaohua Li shli@fb.com Signed-off-by: Sasha Levin sashal@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/md/md.c | 4 ++++ 1 file changed, 4 insertions(+)
--- a/drivers/md/md.c +++ b/drivers/md/md.c @@ -1670,6 +1670,10 @@ static int super_1_validate(struct mddev } else set_bit(In_sync, &rdev->flags); rdev->raid_disk = role; + if (role >= mddev->raid_disks) { + rdev->saved_raid_disk = -1; + rdev->raid_disk = -1; + } break; } if (sb->devflags & WriteMostly1)