3.12-stable review patch. If anyone has any objections, please let me know.
------------------
From: NeilBrown <neilb@xxxxxxx>
commit 8313b8e57f55b15e5b7f7fc5d1630bbf686a9a97 upstream.
If an array is started degraded, and then the missing device
is found it can be re-added and a minimal bitmap-based recovery
will bring it fully up-to-date.
If the array is read-only a recovery would not be allowed.
But also if the array is read-only and the missing device was
present very recently, then there could be no need for any
recovery at all, so we simply include the device in the read-only
array without any recovery.
However... if the missing device was removed a little longer ago
it could be missing some updates, but if a bitmap is present it will
be conditionally accepted pending a bitmap-based update. We don't
currently detect this case properly and will include that old
device into the read-only array with no recovery even though it really
needs a recovery.
This patch keeps track of whether a bitmap-based-recovery is really
needed or not in the new Bitmap_sync rdev flag. If that is set,
then the device will not be added to a read-only array.
Cc: Andrei Warkentin <andreiw@xxxxxxxxxx>
Fixes: d70ed2e4fafdbef0800e73942482bb075c21578b
Signed-off-by: NeilBrown <neilb@xxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/md/md.c | 18 +++++++++++++++---
drivers/md/md.h | 3 +++
2 files changed, 18 insertions(+), 3 deletions(-)
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -1119,6 +1119,7 @@ static int super_90_validate(struct mdde
rdev->raid_disk = -1;
clear_bit(Faulty, &rdev->flags);
clear_bit(In_sync, &rdev->flags);
+ clear_bit(Bitmap_sync, &rdev->flags);
clear_bit(WriteMostly, &rdev->flags);
if (mddev->raid_disks == 0) {
@@ -1197,6 +1198,8 @@ static int super_90_validate(struct mdde
*/
if (ev1 < mddev->bitmap->events_cleared)
return 0;
+ if (ev1 < mddev->events)
+ set_bit(Bitmap_sync, &rdev->flags);
} else {
if (ev1 < mddev->events)
/* just a hot-add of a new device, leave raid_disk at -1 */
@@ -1605,6 +1608,7 @@ static int super_1_validate(struct mddev
rdev->raid_disk = -1;
clear_bit(Faulty, &rdev->flags);
clear_bit(In_sync, &rdev->flags);
+ clear_bit(Bitmap_sync, &rdev->flags);
clear_bit(WriteMostly, &rdev->flags);
if (mddev->raid_disks == 0) {
@@ -1687,6 +1691,8 @@ static int super_1_validate(struct mddev
*/
if (ev1 < mddev->bitmap->events_cleared)
return 0;
+ if (ev1 < mddev->events)
+ set_bit(Bitmap_sync, &rdev->flags);
} else {
if (ev1 < mddev->events)
/* just a hot-add of a new device, leave raid_disk at -1 */
@@ -2830,6 +2836,7 @@ slot_store(struct md_rdev *rdev, const c
else
rdev->saved_raid_disk = -1;
clear_bit(In_sync, &rdev->flags);
+ clear_bit(Bitmap_sync, &rdev->flags);
err = rdev->mddev->pers->
hot_add_disk(rdev->mddev, rdev);
if (err) {
@@ -5773,6 +5780,7 @@ static int add_new_disk(struct mddev * m
info->raid_disk < mddev->raid_disks) {
rdev->raid_disk = info->raid_disk;
set_bit(In_sync, &rdev->flags);
+ clear_bit(Bitmap_sync, &rdev->flags);
} else
rdev->raid_disk = -1;
} else
@@ -7731,7 +7739,8 @@ static int remove_and_add_spares(struct
if (test_bit(Faulty, &rdev->flags))
continue;
if (mddev->ro &&
- rdev->saved_raid_disk < 0)
+ ! (rdev->saved_raid_disk >= 0 &&
+ !test_bit(Bitmap_sync, &rdev->flags)))
continue;
rdev->recovery_offset = 0;
@@ -7812,9 +7821,12 @@ void md_check_recovery(struct mddev *mdd
* As we only add devices that are already in-sync,
* we can activate the spares immediately.
*/
- clear_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
remove_and_add_spares(mddev, NULL);
- mddev->pers->spare_active(mddev);
+ /* There is no thread, but we need to call
+ * ->spare_active and clear saved_raid_disk
+ */
+ md_reap_sync_thread(mddev);
+ clear_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
goto unlock;
}
--- a/drivers/md/md.h
+++ b/drivers/md/md.h
@@ -129,6 +129,9 @@ struct md_rdev {
enum flag_bits {
Faulty, /* device is known to have a fault */
In_sync, /* device is in_sync with rest of array */
+ Bitmap_sync, /* ..actually, not quite In_sync. Need a
+ * bitmap-based recovery to get fully in sync
+ */
Unmerged, /* device is being added to array and should
* be considerred for bvec_merge_fn but not
* yet for actual IO
--
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