From: NeilBrown Date: Thu, 9 Dec 2010 05:36:28 +0000 (+1100) Subject: md: fix bug with re-adding of partially recovered device. X-Git-Url: http://git.lede-project.org./?a=commitdiff_plain;h=1a855a0606653d2d82506281e2c686bacb4b2f45;p=openwrt%2Fstaging%2Fblogic.git md: fix bug with re-adding of partially recovered device. With v0.90 metadata, a hot-spare does not become a full member of the array until recovery is complete. So if we re-add such a device to the array, we know that all of it is as up-to-date as the event count would suggest, and so it a bitmap-based recovery is possible. However with v1.x metadata, the hot-spare immediately becomes a full member of the array, but it record how much of the device has been recovered. If the array is stopped and re-assembled recovery starts from this point. When such a device is hot-added to an array we currently lose the 'how much is recovered' information and incorrectly included it as a full in-sync member (after bitmap-based fixup). This is wrong and unsafe and could corrupt data. So be more careful about setting saved_raid_disk - which is what guides the re-adding of devices back into an array. The new code matches the code in slot_store which does a similar thing, which is encouraging. This is suitable for any -stable kernel. Reported-by: "Dailey, Nate" Cc: stable@kernel.org Signed-off-by: NeilBrown --- diff --git a/drivers/md/md.c b/drivers/md/md.c index d66aaeddf95d..b757da175180 100644 --- a/drivers/md/md.c +++ b/drivers/md/md.c @@ -5159,7 +5159,7 @@ static int add_new_disk(mddev_t * mddev, mdu_disk_info_t *info) PTR_ERR(rdev)); return PTR_ERR(rdev); } - /* set save_raid_disk if appropriate */ + /* set saved_raid_disk if appropriate */ if (!mddev->persistent) { if (info->state & (1<raid_disk < mddev->raid_disks) @@ -5169,7 +5169,10 @@ static int add_new_disk(mddev_t * mddev, mdu_disk_info_t *info) } else super_types[mddev->major_version]. validate_super(mddev, rdev); - rdev->saved_raid_disk = rdev->raid_disk; + if (test_bit(In_sync, &rdev->flags)) + rdev->saved_raid_disk = rdev->raid_disk; + else + rdev->saved_raid_disk = -1; clear_bit(In_sync, &rdev->flags); /* just to be sure */ if (info->state & (1<