On Sun, 2 Dec 2012 13:10:33 +0100 Torsten Kaiser
[off-list ref] wrote:

On Tue, Nov 27, 2012 at 8:08 AM, Torsten Kaiser
[off-list ref] wrote:

quoted

On Tue, Nov 27, 2012 at 2:05 AM, NeilBrown [off-list ref] wrote:

quoted

Can you test to see if this fixes it?

Patch applied, I will try to get it stuck again.
I don't have a reliable reproducers, but if the problem persists I
will definitly report back here.

With this patch I was not able to recreate the hang. Lacking an 100%
way of recreating this, I can't be completely sure of the fix, but as
you understood from the code how this hang could happen, I'm quite
confident that the fix is working.

(As I do not use the raid10 personality only patching raid1.c was
sufficient for me, I didn't test the version that also patched
raid10.c as its not even compiled on my kernel.)

Thanks for the fix!

And thanks for testing!
Linus doesn't seem to have pulled in the fix yet, but hopefully it will be in
3.7.

NeilBrown

Torsten

quoted

quoted

diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c
index 636bae0..a0f7309 100644
--- a/drivers/md/raid1.c
+++ b/drivers/md/raid1.c

@@ -963,7 +963,7 @@ static void raid1_unplug(struct blk_plug_cb *cb, bool from_schedule)
        struct r1conf *conf = mddev->private;
        struct bio *bio;

-       if (from_schedule) {
+       if (from_schedule || current->bio_list) {
                spin_lock_irq(&conf->device_lock);
                bio_list_merge(&conf->pending_bio_list, &plug->pending);
                conf->pending_count += plug->pending_cnt;