[PULL 27/39] block: make bdrv_refresh_limits() to be a transaction action

[Kevin Wolf <kwolf@redhat.com>]

From: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>

To be used in further commit.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Message-Id: <20210428151804.439460-28-vsementsov@virtuozzo.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
---
 include/block/block.h |  3 ++-
 block.c               |  9 ++++-----
 block/io.c            | 31 +++++++++++++++++++++++++++++--
 3 files changed, 35 insertions(+), 8 deletions(-)

diff --git a/include/block/block.h b/include/block/block.h
index 85481a05c6..ad38259c91 100644
--- a/include/block/block.h
+++ b/include/block/block.h
@@ -9,6 +9,7 @@
 #include "block/dirty-bitmap.h"
 #include "block/blockjob.h"
 #include "qemu/hbitmap.h"
+#include "qemu/transactions.h"
 
 /*
  * generated_co_wrapper
@@ -421,7 +422,7 @@ int64_t bdrv_get_allocated_file_size(BlockDriverState *bs);
 BlockMeasureInfo *bdrv_measure(BlockDriver *drv, QemuOpts *opts,
                                BlockDriverState *in_bs, Error **errp);
 void bdrv_get_geometry(BlockDriverState *bs, uint64_t *nb_sectors_ptr);
-void bdrv_refresh_limits(BlockDriverState *bs, Error **errp);
+void bdrv_refresh_limits(BlockDriverState *bs, Transaction *tran, Error **errp);
 int bdrv_commit(BlockDriverState *bs);
 int bdrv_make_empty(BdrvChild *c, Error **errp);
 int bdrv_change_backing_file(BlockDriverState *bs, const char *backing_file,
diff --git a/block.c b/block.c
index 1dc14908ac..9922943793 100644
--- a/block.c
+++ b/block.c
@@ -49,7 +49,6 @@
 #include "qemu/timer.h"
 #include "qemu/cutils.h"
 #include "qemu/id.h"
-#include "qemu/transactions.h"
 #include "block/coroutines.h"
 
 #ifdef CONFIG_BSD
@@ -1577,7 +1576,7 @@ static int bdrv_open_driver(BlockDriverState *bs, BlockDriver *drv,
         return ret;
     }
 
-    bdrv_refresh_limits(bs, &local_err);
+    bdrv_refresh_limits(bs, NULL, &local_err);
     if (local_err) {
         error_propagate(errp, local_err);
         return -EINVAL;
@@ -3363,7 +3362,7 @@ int bdrv_set_backing_hd(BlockDriverState *bs, BlockDriverState *backing_hd,
     }
 
 out:
-    bdrv_refresh_limits(bs, NULL);
+    bdrv_refresh_limits(bs, NULL, NULL);
 
     return ret;
 }
@@ -4847,7 +4846,7 @@ static void bdrv_reopen_commit(BDRVReopenState *reopen_state)
         bdrv_set_backing_hd(bs, reopen_state->new_backing_bs, &error_abort);
     }
 
-    bdrv_refresh_limits(bs, NULL);
+    bdrv_refresh_limits(bs, NULL, NULL);
 }
 
 /*
@@ -5244,7 +5243,7 @@ int bdrv_append(BlockDriverState *bs_new, BlockDriverState *bs_top,
 out:
     tran_finalize(tran, ret);
 
-    bdrv_refresh_limits(bs_top, NULL);
+    bdrv_refresh_limits(bs_top, NULL, NULL);
 
     return ret;
 }
diff --git a/block/io.c b/block/io.c
index ca2dca3007..35b6c56efc 100644
--- a/block/io.c
+++ b/block/io.c
@@ -133,13 +133,40 @@ static void bdrv_merge_limits(BlockLimits *dst, const BlockLimits *src)
     dst->max_iov = MIN_NON_ZERO(dst->max_iov, src->max_iov);
 }
 
-void bdrv_refresh_limits(BlockDriverState *bs, Error **errp)
+typedef struct BdrvRefreshLimitsState {
+    BlockDriverState *bs;
+    BlockLimits old_bl;
+} BdrvRefreshLimitsState;
+
+static void bdrv_refresh_limits_abort(void *opaque)
+{
+    BdrvRefreshLimitsState *s = opaque;
+
+    s->bs->bl = s->old_bl;
+}
+
+static TransactionActionDrv bdrv_refresh_limits_drv = {
+    .abort = bdrv_refresh_limits_abort,
+    .clean = g_free,
+};
+
+/* @tran is allowed to be NULL, in this case no rollback is possible. */
+void bdrv_refresh_limits(BlockDriverState *bs, Transaction *tran, Error **errp)
 {
     ERRP_GUARD();
     BlockDriver *drv = bs->drv;
     BdrvChild *c;
     bool have_limits;
 
+    if (tran) {
+        BdrvRefreshLimitsState *s = g_new(BdrvRefreshLimitsState, 1);
+        *s = (BdrvRefreshLimitsState) {
+            .bs = bs,
+            .old_bl = bs->bl,
+        };
+        tran_add(tran, &bdrv_refresh_limits_drv, s);
+    }
+
     memset(&bs->bl, 0, sizeof(bs->bl));
 
     if (!drv) {
@@ -156,7 +183,7 @@ void bdrv_refresh_limits(BlockDriverState *bs, Error **errp)
     QLIST_FOREACH(c, &bs->children, next) {
         if (c->role & (BDRV_CHILD_DATA | BDRV_CHILD_FILTERED | BDRV_CHILD_COW))
         {
-            bdrv_refresh_limits(c->bs, errp);
+            bdrv_refresh_limits(c->bs, tran, errp);
             if (*errp) {
                 return;
             }
-- 
2.30.2