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authorLaurent Vivier <Laurent.Vivier@bull.net>2008-04-29 01:02:46 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2008-04-29 08:06:23 -0700
commit48cf6061b30205b29b306bf9bc22dd6f0b091461 (patch)
treebba7827177587a17160c29392651aa27aa7f98fd /include/linux/nbd.h
parent8c4dd6068221cd1d0d90490ace80eb4344914a8c (diff)
downloadop-kernel-dev-48cf6061b30205b29b306bf9bc22dd6f0b091461.zip
op-kernel-dev-48cf6061b30205b29b306bf9bc22dd6f0b091461.tar.gz
NBD: allow nbd to be used locally
This patch allows Network Block Device to be mounted locally (nbd-client to nbd-server over 127.0.0.1). It creates a kthread to avoid the deadlock described in NBD tools documentation. So, if nbd-client hangs waiting for pages, the kblockd thread can continue its work and free pages. I have tested the patch to verify that it avoids the hang that always occurs when writing to a localhost nbd connection. I have also tested to verify that no performance degradation results from the additional thread and queue. Patch originally from Laurent Vivier. Signed-off-by: Paul Clements <paul.clements@steeleye.com> Signed-off-by: Laurent Vivier <Laurent.Vivier@bull.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include/linux/nbd.h')
-rw-r--r--include/linux/nbd.h4
1 files changed, 3 insertions, 1 deletions
diff --git a/include/linux/nbd.h b/include/linux/nbd.h
index 9865720..6907551 100644
--- a/include/linux/nbd.h
+++ b/include/linux/nbd.h
@@ -56,9 +56,11 @@ struct nbd_device {
int magic;
spinlock_t queue_lock;
- struct list_head queue_head;/* Requests are added here... */
+ struct list_head queue_head; /* Requests waiting result */
struct request *active_req;
wait_queue_head_t active_wq;
+ struct list_head waiting_queue; /* Requests to be sent */
+ wait_queue_head_t waiting_wq;
struct mutex tx_lock;
struct gendisk *disk;
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