From: Fam Zheng <famz@redhat.com>
Date: Tue, 10 Jul 2018 06:31:20 +0000 (+0800)
Subject: block: Fix handling of image enlarging write
X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=7f8f03ef6d5c82fee1c22be06fc9de4a16ad7059;p=qemu.git

block: Fix handling of image enlarging write

Two problems exist when a write request that enlarges the image (i.e.
write beyond EOF) finishes:

1) parent is not notified about size change;
2) dirty bitmap is not resized although we try to set the dirty bits;

Fix them just like how bdrv_co_truncate works.

Reported-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Fam Zheng <famz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
---

diff --git a/block/io.c b/block/io.c
index 313fe0776c..c88b2b48d7 100644
--- a/block/io.c
+++ b/block/io.c
@@ -40,6 +40,7 @@
 
 static AioWait drain_all_aio_wait;
 
+static void bdrv_parent_cb_resize(BlockDriverState *bs);
 static int coroutine_fn bdrv_co_do_pwrite_zeroes(BlockDriverState *bs,
     int64_t offset, int bytes, BdrvRequestFlags flags);
 
@@ -1621,13 +1622,16 @@ bdrv_co_write_req_finish(BdrvChild *child, int64_t offset, uint64_t bytes,
     BlockDriverState *bs = child->bs;
 
     atomic_inc(&bs->write_gen);
-    bdrv_set_dirty(bs, offset, bytes);
 
     stat64_max(&bs->wr_highest_offset, offset + bytes);
 
-    if (ret == 0) {
-        bs->total_sectors = MAX(bs->total_sectors, end_sector);
+    if (ret == 0 &&
+        end_sector > bs->total_sectors) {
+        bs->total_sectors = end_sector;
+        bdrv_parent_cb_resize(bs);
+        bdrv_dirty_bitmap_truncate(bs, end_sector << BDRV_SECTOR_BITS);
     }
+    bdrv_set_dirty(bs, offset, bytes);
 }
 
 /*