This is a note to let you know that I've just added the patch titled
md: fix bug with re-adding of partially recovered device.
to the 2.6.36-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
md-fix-bug-with-re-adding-of-partially-recovered-device.patch
and it can be found in the queue-2.6.36 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <[email protected]> know about it.
>From 1a855a0606653d2d82506281e2c686bacb4b2f45 Mon Sep 17 00:00:00 2001
From: NeilBrown <[email protected]>
Date: Thu, 9 Dec 2010 16:36:28 +1100
Subject: md: fix bug with re-adding of partially recovered device.
From: NeilBrown <[email protected]>
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" <[email protected]>
Signed-off-by: NeilBrown <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
drivers/md/md.c | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -5150,7 +5150,7 @@ static int add_new_disk(mddev_t * mddev,
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)
@@ -5160,7 +5160,10 @@ static int add_new_disk(mddev_t * mddev,
} 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))
Patches currently in stable-queue which might be from [email protected] are
queue-2.6.36/md-protect-against-null-reference-when-waiting-to-start-a-raid10.patch
queue-2.6.36/md-fix-bug-with-re-adding-of-partially-recovered-device.patch
queue-2.6.36/nfsd-fix-possible-bug_on-firing-in-set_change_info.patch
queue-2.6.36/sunrpc-prevent-use-after-free-on-clearing-xpt_busy.patch
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