This is a note to let you know that I've just added the patch titled
virtio-blk: Don't free ida when disk is in use
to the 3.4-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:
virtio-blk-don-t-free-ida-when-disk-is-in-use.patch
and it can be found in the queue-3.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 63dddb4936fa86057e7f94a0bd10cb8ac25bc7f3 Mon Sep 17 00:00:00 2001
From: Alexander Graf <agraf@xxxxxxx>
Date: Wed, 2 Jan 2013 15:37:17 +1030
Subject: virtio-blk: Don't free ida when disk is in use
From: Alexander Graf <agraf@xxxxxxx>
commit f4953fe6c4aeada2d5cafd78aa97587a46d2d8f9 upstream.
When a file system is mounted on a virtio-blk disk, we then remove it
and then reattach it, the reattached disk gets the same disk name and
ids as the hot removed one.
This leads to very nasty effects - mostly rendering the newly attached
device completely unusable.
Trying what happens when I do the same thing with a USB device, I saw
that the sd node simply doesn't get free'd when a device gets forcefully
removed.
Imitate the same behavior for vd devices. This way broken vd devices
simply are never free'd and newly attached ones keep working just fine.
Signed-off-by: Alexander Graf <agraf@xxxxxxx>
Signed-off-by: Rusty Russell <rusty@xxxxxxxxxxxxxxx>
Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
Cc: Yijing Wang <wangyijing@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/block/virtio_blk.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)
--- a/drivers/block/virtio_blk.c
+++ b/drivers/block/virtio_blk.c
@@ -573,6 +573,7 @@ static void __devexit virtblk_remove(str
{
struct virtio_blk *vblk = vdev->priv;
int index = vblk->index;
+ int refc;
/* Prevent config work handler from accessing the device. */
mutex_lock(&vblk->config_lock);
@@ -587,11 +588,15 @@ static void __devexit virtblk_remove(str
flush_work(&vblk->config_work);
+ refc = atomic_read(&disk_to_dev(vblk->disk)->kobj.kref.refcount);
put_disk(vblk->disk);
mempool_destroy(vblk->pool);
vdev->config->del_vqs(vdev);
kfree(vblk);
- ida_simple_remove(&vd_index_ida, index);
+
+ /* Only free device id if we don't have any users */
+ if (refc == 1)
+ ida_simple_remove(&vd_index_ida, index);
}
#ifdef CONFIG_PM
Patches currently in stable-queue which might be from agraf@xxxxxxx are
queue-3.4/virtio-blk-don-t-free-ida-when-disk-is-in-use.patch
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