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authorStefan Hajnoczi <stefanha@linux.vnet.ibm.com>2011-11-14 12:44:19 +0000
committerKevin Wolf <kwolf@redhat.com>2011-12-05 14:51:36 +0100
commit376ae3f1cb5a08f53c9425bfaf90b3f70ab240f1 (patch)
treef66c28d20b2756d4768551c711b5697ac8bfaf5a
parent05c4af54c670f5143bd4ac5d79aa1ef53a9f31ca (diff)
downloadqemu-arm-376ae3f1cb5a08f53c9425bfaf90b3f70ab240f1.tar.gz
block: add .bdrv_co_is_allocated()
This patch adds the .bdrv_co_is_allocated() interface which is identical to .bdrv_is_allocated() but runs in coroutine context. Running in coroutine context implies that other coroutines might be performing I/O at the same time. Therefore it must be safe to run while the following BlockDriver functions are in-flight: .bdrv_co_readv() .bdrv_co_writev() .bdrv_co_flush() .bdrv_co_is_allocated() The new .bdrv_co_is_allocated() interface is useful because it can be used when a VM is running, whereas .bdrv_is_allocated() is a synchronous interface that does not cope with parallel requests. Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
-rw-r--r--block.c37
-rw-r--r--block_int.h2
2 files changed, 39 insertions, 0 deletions
diff --git a/block.c b/block.c
index 0d5bee0653..611c429be9 100644
--- a/block.c
+++ b/block.c
@@ -1887,6 +1887,26 @@ int bdrv_has_zero_init(BlockDriverState *bs)
return 1;
}
+typedef struct BdrvCoIsAllocatedData {
+ BlockDriverState *bs;
+ int64_t sector_num;
+ int nb_sectors;
+ int *pnum;
+ int ret;
+ bool done;
+} BdrvCoIsAllocatedData;
+
+/* Coroutine wrapper for bdrv_is_allocated() */
+static void coroutine_fn bdrv_is_allocated_co_entry(void *opaque)
+{
+ BdrvCoIsAllocatedData *data = opaque;
+ BlockDriverState *bs = data->bs;
+
+ data->ret = bs->drv->bdrv_co_is_allocated(bs, data->sector_num,
+ data->nb_sectors, data->pnum);
+ data->done = true;
+}
+
/*
* Returns true iff the specified sector is present in the disk image. Drivers
* not implementing the functionality are assumed to not support backing files,
@@ -1902,6 +1922,23 @@ int bdrv_is_allocated(BlockDriverState *bs, int64_t sector_num, int nb_sectors,
int *pnum)
{
int64_t n;
+ if (bs->drv->bdrv_co_is_allocated) {
+ Coroutine *co;
+ BdrvCoIsAllocatedData data = {
+ .bs = bs,
+ .sector_num = sector_num,
+ .nb_sectors = nb_sectors,
+ .pnum = pnum,
+ .done = false,
+ };
+
+ co = qemu_coroutine_create(bdrv_is_allocated_co_entry);
+ qemu_coroutine_enter(co, &data);
+ while (!data.done) {
+ qemu_aio_wait();
+ }
+ return data.ret;
+ }
if (!bs->drv->bdrv_is_allocated) {
if (sector_num >= bs->total_sectors) {
*pnum = 0;
diff --git a/block_int.h b/block_int.h
index e2799e4f6b..d5b5457d90 100644
--- a/block_int.h
+++ b/block_int.h
@@ -103,6 +103,8 @@ struct BlockDriver {
int64_t sector_num, int nb_sectors, QEMUIOVector *qiov);
int coroutine_fn (*bdrv_co_discard)(BlockDriverState *bs,
int64_t sector_num, int nb_sectors);
+ int coroutine_fn (*bdrv_co_is_allocated)(BlockDriverState *bs,
+ int64_t sector_num, int nb_sectors, int *pnum);
/*
* Invalidate any cached meta-data.