This is a note to let you know that I've just added the patch titled
rbd: don't hold spinlock during messenger flush
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:
0033-rbd-don-t-hold-spinlock-during-messenger-flush.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 <[email protected]> know about it.
>From 6d7e495a8347311ddf5f1785c94ce71627b3efe0 Mon Sep 17 00:00:00 2001
From: Alex Elder <[email protected]>
Date: Wed, 4 Apr 2012 13:35:44 -0500
Subject: rbd: don't hold spinlock during messenger flush
From: Alex Elder <[email protected]>
(cherry picked from commit cd9d9f5df6098c50726200d4185e9e8da32785b3)
A recent change made changes to the rbd_client_list be protected by
a spinlock. Unfortunately in rbd_put_client(), the lock is taken
before possibly dropping the last reference to an rbd_client, and on
the last reference that eventually calls flush_workqueue() which can
sleep.
The problem was flagged by a debug spinlock warning:
BUG: spinlock wrong CPU on CPU#3, rbd/27814
The solution is to move the spinlock acquisition and release inside
rbd_client_release(), which is the spot where it's really needed for
protecting the removal of the rbd_client from the client list.
Signed-off-by: Alex Elder <[email protected]>
Reviewed-by: Sage Weil <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
drivers/block/rbd.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
--- a/drivers/block/rbd.c
+++ b/drivers/block/rbd.c
@@ -450,7 +450,9 @@ static void rbd_client_release(struct kr
struct rbd_client *rbdc = container_of(kref, struct rbd_client, kref);
dout("rbd_release_client %p\n", rbdc);
+ spin_lock(&rbd_client_list_lock);
list_del(&rbdc->node);
+ spin_unlock(&rbd_client_list_lock);
ceph_destroy_client(rbdc->client);
kfree(rbdc->rbd_opts);
@@ -463,9 +465,7 @@ static void rbd_client_release(struct kr
*/
static void rbd_put_client(struct rbd_device *rbd_dev)
{
- spin_lock(&rbd_client_list_lock);
kref_put(&rbd_dev->rbd_client->kref, rbd_client_release);
- spin_unlock(&rbd_client_list_lock);
rbd_dev->rbd_client = NULL;
}
Patches currently in stable-queue which might be from [email protected] are
queue-3.4/0033-rbd-don-t-hold-spinlock-during-messenger-flush.patch
queue-3.4/0006-ceph-osd_client-fix-endianness-bug-in-osd_req_encode.patch
queue-3.4/0034-rbd-protect-read-of-snapshot-sequence-number.patch
queue-3.4/0035-rbd-store-snapshot-id-instead-of-index.patch
--
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