From 81ae4595abc28cfb7936d81cf767f837cb9de878 Mon Sep 17 00:00:00 2001
From: Jeffrey Cody <jcody@redhat.com>
Date: Wed, 21 Mar 2012 21:54:52 +0100
Subject: [PATCH 25/55] block: add request tracking
RH-Author: Jeffrey Cody <jcody@redhat.com>
Message-id: <9ee6323d7fd898bdbe01f87e6ea20578317dacf3.1332362400.git.jcody@redhat.com>
Patchwork-id: 38875
O-Subject: [RHEL6.3 qemu-kvm PATCH v8 25/54] block: add request tracking
Bugzilla: 582475
RH-Acked-by: Paolo Bonzini <pbonzini@redhat.com>
RH-Acked-by: Marcelo Tosatti <mtosatti@redhat.com>
RH-Acked-by: Kevin Wolf <kwolf@redhat.com>
From: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
The block layer does not know about pending requests. This information
is necessary for copy-on-read since overlapping requests must be
serialized to prevent races that corrupt the image.
The BlockDriverState gets a new tracked_request list field which
contains all pending requests. Each request is a BdrvTrackedRequest
record with sector_num, nb_sectors, and is_write fields.
Note that request tracking is always enabled but hopefully this extra
work is so small that it doesn't justify adding an enable/disable flag.
Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
(cherry picked from commit dbffbdcfff69431b622866ac5ea78df74fdc02d4)
Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
Signed-off-by: Jeff Cody <jcody@redhat.com>
---
block.c | 48 +++++++++++++++++++++++++++++++++++++++++++++++-
block_int.h | 4 ++++
2 files changed, 51 insertions(+), 1 deletions(-)
Signed-off-by: Michal Novotny <minovotn@redhat.com>
---
block.c | 48 +++++++++++++++++++++++++++++++++++++++++++++++-
block_int.h | 4 ++++
2 files changed, 51 insertions(+), 1 deletions(-)
diff --git a/block.c b/block.c
index fdbfbd5..50d80fe 100644
--- a/block.c
+++ b/block.c
@@ -1076,6 +1076,42 @@ ro_cleanup:
return ret;
}
+struct BdrvTrackedRequest {
+ BlockDriverState *bs;
+ int64_t sector_num;
+ int nb_sectors;
+ bool is_write;
+ QLIST_ENTRY(BdrvTrackedRequest) list;
+};
+
+/**
+ * Remove an active request from the tracked requests list
+ *
+ * This function should be called when a tracked request is completing.
+ */
+static void tracked_request_end(BdrvTrackedRequest *req)
+{
+ QLIST_REMOVE(req, list);
+}
+
+/**
+ * Add an active request to the tracked requests list
+ */
+static void tracked_request_begin(BdrvTrackedRequest *req,
+ BlockDriverState *bs,
+ int64_t sector_num,
+ int nb_sectors, bool is_write)
+{
+ *req = (BdrvTrackedRequest){
+ .bs = bs,
+ .sector_num = sector_num,
+ .nb_sectors = nb_sectors,
+ .is_write = is_write,
+ };
+
+ QLIST_INSERT_HEAD(&bs->tracked_requests, req, list);
+}
+
/*
* Return values:
* 0 - success
@@ -1349,6 +1385,8 @@ static int coroutine_fn bdrv_co_do_readv(BlockDriverState *bs,
int64_t sector_num, int nb_sectors, QEMUIOVector *qiov)
{
BlockDriver *drv = bs->drv;
+ BdrvTrackedRequest req;
+ int ret;
if (!drv) {
return -ENOMEDIUM;
@@ -1357,7 +1395,10 @@ static int coroutine_fn bdrv_co_do_readv(BlockDriverState *bs,
return -EIO;
}
- return drv->bdrv_co_readv(bs, sector_num, nb_sectors, qiov);
+ tracked_request_begin(&req, bs, sector_num, nb_sectors, false);
+ ret = drv->bdrv_co_readv(bs, sector_num, nb_sectors, qiov);
+ tracked_request_end(&req);
+ return ret;
}
int coroutine_fn bdrv_co_readv(BlockDriverState *bs, int64_t sector_num,
@@ -1375,6 +1416,7 @@ static int coroutine_fn bdrv_co_do_writev(BlockDriverState *bs,
int64_t sector_num, int nb_sectors, QEMUIOVector *qiov)
{
BlockDriver *drv = bs->drv;
+ BdrvTrackedRequest req;
int ret;
if (!bs->drv) {
@@ -1387,6 +1429,8 @@ static int coroutine_fn bdrv_co_do_writev(BlockDriverState *bs,
return -EIO;
}
+ tracked_request_begin(&req, bs, sector_num, nb_sectors, true);
+
ret = drv->bdrv_co_writev(bs, sector_num, nb_sectors, qiov);
if (bs->dirty_bitmap) {
@@ -1397,6 +1441,8 @@ static int coroutine_fn bdrv_co_do_writev(BlockDriverState *bs,
bs->wr_highest_sector = sector_num + nb_sectors - 1;
}
+ tracked_request_end(&req);
+
return ret;
}
diff --git a/block_int.h b/block_int.h
index 7655876..f3cd33a 100644
--- a/block_int.h
+++ b/block_int.h
@@ -42,6 +42,8 @@
#define BLOCK_OPT_TABLE_SIZE "table_size"
#define BLOCK_OPT_PREALLOC "preallocation"
+typedef struct BdrvTrackedRequest BdrvTrackedRequest;
+
typedef struct AIOPool {
void (*cancel)(BlockDriverAIOCB *acb);
int aiocb_size;
@@ -211,6 +213,8 @@ struct BlockDriverState {
int in_use; /* users other than guest access, eg. block migration */
QTAILQ_ENTRY(BlockDriverState) list;
void *private;
+
+ QLIST_HEAD(, BdrvTrackedRequest) tracked_requests;
};
struct BlockDriverAIOCB {
--
1.7.7.6