| From aefb371f30ba9467a19e739c96e47629d7f46849 Mon Sep 17 00:00:00 2001 |
| From: NeilBrown <neilb@suse.de> |
| Date: Thu, 9 Dec 2010 16:36:28 +1100 |
| Subject: [PATCH] md: fix bug with re-adding of partially recovered device. |
| |
| commit 1a855a0606653d2d82506281e2c686bacb4b2f45 upstream. |
| |
| 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" <Nate.Dailey@stratus.com> |
| Signed-off-by: NeilBrown <neilb@suse.de> |
| Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> |
| |
| diff --git a/drivers/md/md.c b/drivers/md/md.c |
| index 92dbef5..cf511de 100644 |
| --- a/drivers/md/md.c |
| +++ b/drivers/md/md.c |
| @@ -5008,7 +5008,7 @@ 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<<MD_DISK_SYNC) && |
| info->raid_disk < mddev->raid_disks) |
| @@ -5018,7 +5018,10 @@ 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<<MD_DISK_WRITEMOSTLY)) |
| -- |
| 1.7.4.4 |
| |
