block: Update BlockLimits when they might have changed

When reopening with different flags, or when backing files disappear
from the chain, the limits may change. Make sure they get updated in
these cases.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Wenchao Xia <xiawenc@linux.vnet.ibm.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Benoît Canet <benoit@irqsave.net>

3 files changed, 7 insertions, 1 deletions

diff --git a/block.c b/block.c
index 8a6692719a..9d0cfc46da 100644
--- a/block.c
+++ b/block.c
@@ -483,7 +483,7 @@ int bdrv_create_file(const char* filename, QEMUOptionParameter *options,
     return ret;
 }
 
-static int bdrv_refresh_limits(BlockDriverState *bs)
+int bdrv_refresh_limits(BlockDriverState *bs)
 {
     BlockDriver *drv = bs->drv;
 
@@ -1607,6 +1607,8 @@ void bdrv_reopen_commit(BDRVReopenState *reopen_state)
     reopen_state->bs->enable_write_cache = !!(reopen_state->flags &
                                               BDRV_O_CACHE_WB);
     reopen_state->bs->read_only = !(reopen_state->flags & BDRV_O_RDWR);
+
+    bdrv_refresh_limits(reopen_state->bs);
 }
 
 /*
@@ -2441,6 +2443,7 @@ int bdrv_drop_intermediate(BlockDriverState *active, BlockDriverState *top,
     }
     new_top_bs->backing_hd = base_bs;
 
+    bdrv_refresh_limits(new_top_bs);
 
     QSIMPLEQ_FOREACH_SAFE(intermediate_state, &states_to_delete, entry, next) {
         /* so that bdrv_close() does not recursively close the chain */
diff --git a/block/stream.c b/block/stream.c
index 46bec7d379..dd0b4ac3d2 100644
--- a/block/stream.c
+++ b/block/stream.c
@@ -75,6 +75,8 @@ static void close_unused_images(BlockDriverState *top, BlockDriverState *base,
         unused->backing_hd = NULL;
         bdrv_unref(unused);
     }
+
+    bdrv_refresh_limits(top);
 }
 
 static void coroutine_fn stream_run(void *opaque)
diff --git a/include/block/block.h b/include/block/block.h
index 59d9f12ce4..00a8790660 100644
--- a/include/block/block.h
+++ b/include/block/block.h
@@ -253,6 +253,7 @@ int bdrv_truncate(BlockDriverState *bs, int64_t offset);
 int64_t bdrv_getlength(BlockDriverState *bs);
 int64_t bdrv_get_allocated_file_size(BlockDriverState *bs);
 void bdrv_get_geometry(BlockDriverState *bs, uint64_t *nb_sectors_ptr);
+int bdrv_refresh_limits(BlockDriverState *bs);
 int bdrv_commit(BlockDriverState *bs);
 int bdrv_commit_all(void);
 int bdrv_change_backing_file(BlockDriverState *bs,