[libvirt] [PULL v3 04/19] block/qcow2: proper locking on bitmap add/remove paths
John Snow
jsnow at redhat.com
Thu Oct 17 21:54:21 UTC 2019
From: Vladimir Sementsov-Ogievskiy <vsementsov at virtuozzo.com>
qmp_block_dirty_bitmap_add and do_block_dirty_bitmap_remove do acquire
aio context since 0a6c86d024c52b. But this is not enough: we also must
lock qcow2 mutex when access in-image metadata. Especially it concerns
freeing qcow2 clusters.
To achieve this, move qcow2_can_store_new_dirty_bitmap and
qcow2_remove_persistent_dirty_bitmap to coroutine context.
Since we work in coroutines in correct aio context, we don't need
context acquiring in blockdev.c anymore, drop it.
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov at virtuozzo.com>
Reviewed-by: John Snow <jsnow at redhat.com>
Message-id: 20190920082543.23444-4-vsementsov at virtuozzo.com
Signed-off-by: John Snow <jsnow at redhat.com>
---
block/qcow2.h | 11 ++--
include/block/block_int.h | 10 ++--
block/dirty-bitmap.c | 102 +++++++++++++++++++++++++++++++++++---
block/qcow2-bitmap.c | 24 ++++++---
block/qcow2.c | 5 +-
blockdev.c | 27 +++-------
6 files changed, 131 insertions(+), 48 deletions(-)
diff --git a/block/qcow2.h b/block/qcow2.h
index 08b4c15dc4..0f3d9b088e 100644
--- a/block/qcow2.h
+++ b/block/qcow2.h
@@ -746,12 +746,13 @@ int qcow2_reopen_bitmaps_rw(BlockDriverState *bs, Error **errp);
int qcow2_truncate_bitmaps_check(BlockDriverState *bs, Error **errp);
void qcow2_store_persistent_dirty_bitmaps(BlockDriverState *bs, Error **errp);
int qcow2_reopen_bitmaps_ro(BlockDriverState *bs, Error **errp);
-bool qcow2_can_store_new_dirty_bitmap(BlockDriverState *bs,
- const char *name,
- uint32_t granularity,
- Error **errp);
-int qcow2_remove_persistent_dirty_bitmap(BlockDriverState *bs, const char *name,
+bool qcow2_co_can_store_new_dirty_bitmap(BlockDriverState *bs,
+ const char *name,
+ uint32_t granularity,
Error **errp);
+int qcow2_co_remove_persistent_dirty_bitmap(BlockDriverState *bs,
+ const char *name,
+ Error **errp);
ssize_t coroutine_fn
qcow2_co_compress(BlockDriverState *bs, void *dest, size_t dest_size,
diff --git a/include/block/block_int.h b/include/block/block_int.h
index 6b511dd889..32fb493cbb 100644
--- a/include/block/block_int.h
+++ b/include/block/block_int.h
@@ -553,13 +553,13 @@ struct BlockDriver {
* field of BlockDirtyBitmap's in case of success.
*/
int (*bdrv_reopen_bitmaps_rw)(BlockDriverState *bs, Error **errp);
- bool (*bdrv_can_store_new_dirty_bitmap)(BlockDriverState *bs,
- const char *name,
- uint32_t granularity,
- Error **errp);
- int (*bdrv_remove_persistent_dirty_bitmap)(BlockDriverState *bs,
+ bool (*bdrv_co_can_store_new_dirty_bitmap)(BlockDriverState *bs,
const char *name,
+ uint32_t granularity,
Error **errp);
+ int (*bdrv_co_remove_persistent_dirty_bitmap)(BlockDriverState *bs,
+ const char *name,
+ Error **errp);
/**
* Register/unregister a buffer for I/O. For example, when the driver is
diff --git a/block/dirty-bitmap.c b/block/dirty-bitmap.c
index d1ae2e1922..03e0872b97 100644
--- a/block/dirty-bitmap.c
+++ b/block/dirty-bitmap.c
@@ -26,6 +26,7 @@
#include "trace.h"
#include "block/block_int.h"
#include "block/blockjob.h"
+#include "qemu/main-loop.h"
struct BdrvDirtyBitmap {
QemuMutex *mutex;
@@ -455,18 +456,59 @@ void bdrv_release_named_dirty_bitmaps(BlockDriverState *bs)
* not fail.
* This function doesn't release corresponding BdrvDirtyBitmap.
*/
+static int coroutine_fn
+bdrv_co_remove_persistent_dirty_bitmap(BlockDriverState *bs, const char *name,
+ Error **errp)
+{
+ if (bs->drv && bs->drv->bdrv_co_remove_persistent_dirty_bitmap) {
+ return bs->drv->bdrv_co_remove_persistent_dirty_bitmap(bs, name, errp);
+ }
+
+ return 0;
+}
+
+typedef struct BdrvRemovePersistentDirtyBitmapCo {
+ BlockDriverState *bs;
+ const char *name;
+ Error **errp;
+ int ret;
+} BdrvRemovePersistentDirtyBitmapCo;
+
+static void coroutine_fn
+bdrv_co_remove_persistent_dirty_bitmap_entry(void *opaque)
+{
+ BdrvRemovePersistentDirtyBitmapCo *s = opaque;
+
+ s->ret = bdrv_co_remove_persistent_dirty_bitmap(s->bs, s->name, s->errp);
+ aio_wait_kick();
+}
+
int bdrv_remove_persistent_dirty_bitmap(BlockDriverState *bs, const char *name,
Error **errp)
{
- if (bs->drv && bs->drv->bdrv_remove_persistent_dirty_bitmap) {
- return bs->drv->bdrv_remove_persistent_dirty_bitmap(bs, name, errp);
+ if (qemu_in_coroutine()) {
+ return bdrv_co_remove_persistent_dirty_bitmap(bs, name, errp);
+ } else {
+ Coroutine *co;
+ BdrvRemovePersistentDirtyBitmapCo s = {
+ .bs = bs,
+ .name = name,
+ .errp = errp,
+ .ret = -EINPROGRESS,
+ };
+
+ co = qemu_coroutine_create(bdrv_co_remove_persistent_dirty_bitmap_entry,
+ &s);
+ bdrv_coroutine_enter(bs, co);
+ BDRV_POLL_WHILE(bs, s.ret == -EINPROGRESS);
+
+ return s.ret;
}
-
- return 0;
}
-bool bdrv_can_store_new_dirty_bitmap(BlockDriverState *bs, const char *name,
- uint32_t granularity, Error **errp)
+static bool coroutine_fn
+bdrv_co_can_store_new_dirty_bitmap(BlockDriverState *bs, const char *name,
+ uint32_t granularity, Error **errp)
{
BlockDriver *drv = bs->drv;
@@ -477,14 +519,58 @@ bool bdrv_can_store_new_dirty_bitmap(BlockDriverState *bs, const char *name,
return false;
}
- if (!drv->bdrv_can_store_new_dirty_bitmap) {
+ if (!drv->bdrv_co_can_store_new_dirty_bitmap) {
error_setg_errno(errp, ENOTSUP,
"Can't store persistent bitmaps to %s",
bdrv_get_device_or_node_name(bs));
return false;
}
- return drv->bdrv_can_store_new_dirty_bitmap(bs, name, granularity, errp);
+ return drv->bdrv_co_can_store_new_dirty_bitmap(bs, name, granularity, errp);
+}
+
+typedef struct BdrvCanStoreNewDirtyBitmapCo {
+ BlockDriverState *bs;
+ const char *name;
+ uint32_t granularity;
+ Error **errp;
+ bool ret;
+
+ bool in_progress;
+} BdrvCanStoreNewDirtyBitmapCo;
+
+static void coroutine_fn bdrv_co_can_store_new_dirty_bitmap_entry(void *opaque)
+{
+ BdrvCanStoreNewDirtyBitmapCo *s = opaque;
+
+ s->ret = bdrv_co_can_store_new_dirty_bitmap(s->bs, s->name, s->granularity,
+ s->errp);
+ s->in_progress = false;
+ aio_wait_kick();
+}
+
+bool bdrv_can_store_new_dirty_bitmap(BlockDriverState *bs, const char *name,
+ uint32_t granularity, Error **errp)
+{
+ if (qemu_in_coroutine()) {
+ return bdrv_co_can_store_new_dirty_bitmap(bs, name, granularity, errp);
+ } else {
+ Coroutine *co;
+ BdrvCanStoreNewDirtyBitmapCo s = {
+ .bs = bs,
+ .name = name,
+ .granularity = granularity,
+ .errp = errp,
+ .in_progress = true,
+ };
+
+ co = qemu_coroutine_create(bdrv_co_can_store_new_dirty_bitmap_entry,
+ &s);
+ bdrv_coroutine_enter(bs, co);
+ BDRV_POLL_WHILE(bs, s.in_progress);
+
+ return s.ret;
+ }
}
void bdrv_disable_dirty_bitmap(BdrvDirtyBitmap *bitmap)
diff --git a/block/qcow2-bitmap.c b/block/qcow2-bitmap.c
index 9821c1628f..644837eb03 100644
--- a/block/qcow2-bitmap.c
+++ b/block/qcow2-bitmap.c
@@ -1404,12 +1404,13 @@ static Qcow2Bitmap *find_bitmap_by_name(Qcow2BitmapList *bm_list,
return NULL;
}
-int qcow2_remove_persistent_dirty_bitmap(BlockDriverState *bs, const char *name,
- Error **errp)
+int coroutine_fn qcow2_co_remove_persistent_dirty_bitmap(BlockDriverState *bs,
+ const char *name,
+ Error **errp)
{
int ret;
BDRVQcow2State *s = bs->opaque;
- Qcow2Bitmap *bm;
+ Qcow2Bitmap *bm = NULL;
Qcow2BitmapList *bm_list;
if (s->nb_bitmaps == 0) {
@@ -1418,10 +1419,13 @@ int qcow2_remove_persistent_dirty_bitmap(BlockDriverState *bs, const char *name,
return 0;
}
+ qemu_co_mutex_lock(&s->lock);
+
bm_list = bitmap_list_load(bs, s->bitmap_directory_offset,
s->bitmap_directory_size, errp);
if (bm_list == NULL) {
- return -EIO;
+ ret = -EIO;
+ goto out;
}
bm = find_bitmap_by_name(bm_list, name);
@@ -1441,6 +1445,8 @@ int qcow2_remove_persistent_dirty_bitmap(BlockDriverState *bs, const char *name,
free_bitmap_clusters(bs, &bm->table);
out:
+ qemu_co_mutex_unlock(&s->lock);
+
bitmap_free(bm);
bitmap_list_free(bm_list);
@@ -1615,10 +1621,10 @@ int qcow2_reopen_bitmaps_ro(BlockDriverState *bs, Error **errp)
return 0;
}
-bool qcow2_can_store_new_dirty_bitmap(BlockDriverState *bs,
- const char *name,
- uint32_t granularity,
- Error **errp)
+bool coroutine_fn qcow2_co_can_store_new_dirty_bitmap(BlockDriverState *bs,
+ const char *name,
+ uint32_t granularity,
+ Error **errp)
{
BDRVQcow2State *s = bs->opaque;
bool found;
@@ -1655,8 +1661,10 @@ bool qcow2_can_store_new_dirty_bitmap(BlockDriverState *bs,
goto fail;
}
+ qemu_co_mutex_lock(&s->lock);
bm_list = bitmap_list_load(bs, s->bitmap_directory_offset,
s->bitmap_directory_size, errp);
+ qemu_co_mutex_unlock(&s->lock);
if (bm_list == NULL) {
goto fail;
}
diff --git a/block/qcow2.c b/block/qcow2.c
index 7961c05783..7062eccaee 100644
--- a/block/qcow2.c
+++ b/block/qcow2.c
@@ -5407,8 +5407,9 @@ BlockDriver bdrv_qcow2 = {
.bdrv_attach_aio_context = qcow2_attach_aio_context,
.bdrv_reopen_bitmaps_rw = qcow2_reopen_bitmaps_rw,
- .bdrv_can_store_new_dirty_bitmap = qcow2_can_store_new_dirty_bitmap,
- .bdrv_remove_persistent_dirty_bitmap = qcow2_remove_persistent_dirty_bitmap,
+ .bdrv_co_can_store_new_dirty_bitmap = qcow2_co_can_store_new_dirty_bitmap,
+ .bdrv_co_remove_persistent_dirty_bitmap =
+ qcow2_co_remove_persistent_dirty_bitmap,
};
static void bdrv_qcow2_init(void)
diff --git a/blockdev.c b/blockdev.c
index a45458a60a..7e12919724 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -2898,16 +2898,10 @@ void qmp_block_dirty_bitmap_add(const char *node, const char *name,
disabled = false;
}
- if (persistent) {
- AioContext *aio_context = bdrv_get_aio_context(bs);
- bool ok;
-
- aio_context_acquire(aio_context);
- ok = bdrv_can_store_new_dirty_bitmap(bs, name, granularity, errp);
- aio_context_release(aio_context);
- if (!ok) {
- return;
- }
+ if (persistent &&
+ !bdrv_can_store_new_dirty_bitmap(bs, name, granularity, errp))
+ {
+ return;
}
bitmap = bdrv_create_dirty_bitmap(bs, granularity, name, errp);
@@ -2939,17 +2933,10 @@ static BdrvDirtyBitmap *do_block_dirty_bitmap_remove(
return NULL;
}
- if (bdrv_dirty_bitmap_get_persistence(bitmap)) {
- int ret;
- AioContext *aio_context = bdrv_get_aio_context(bs);
-
- aio_context_acquire(aio_context);
- ret = bdrv_remove_persistent_dirty_bitmap(bs, name, errp);
- aio_context_release(aio_context);
-
- if (ret < 0) {
+ if (bdrv_dirty_bitmap_get_persistence(bitmap) &&
+ bdrv_remove_persistent_dirty_bitmap(bs, name, errp) < 0)
+ {
return NULL;
- }
}
if (release) {
--
2.21.0
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