From fe16c7ddf82b25e54cb76936a4cdf6bf9327ece5 Mon Sep 17 00:00:00 2001 From: Max Reitz Date: Thu, 30 Jul 2020 14:02:33 +0200 Subject: [PATCH] qcow2: Release read-only bitmaps when inactivated During migration, we release all bitmaps after storing them on disk, as long as they are (1) stored on disk, (2) not read-only, and (3) consistent. (2) seems arbitrary, though. The reason we do not release them is because we do not write them, as there is no need to; and then we just forget about all bitmaps that we have not written to the file. However, read-only persistent bitmaps are still in the file and in sync with their in-memory representation, so we may as well release them just like any R/W bitmap that we have updated. It leads to actual problems, too: After migration, letting the source continue may result in an error if there were any bitmaps on read-only nodes (such as backing images), because those have not been released by bdrv_inactive_all(), but bdrv_invalidate_cache_all() attempts to reload them (which fails, because they are still present in memory). Signed-off-by: Max Reitz Message-Id: <20200730120234.49288-2-mreitz@redhat.com> Tested-by: Peter Krempa Reviewed-by: Eric Blake Signed-off-by: Eric Blake --- block/qcow2-bitmap.c | 23 +++++++++++++++++++---- 1 file changed, 19 insertions(+), 4 deletions(-) diff --git a/block/qcow2-bitmap.c b/block/qcow2-bitmap.c index 1f38806ca6..8c34b2aef7 100644 --- a/block/qcow2-bitmap.c +++ b/block/qcow2-bitmap.c @@ -1562,11 +1562,22 @@ void qcow2_store_persistent_dirty_bitmaps(BlockDriverState *bs, Qcow2Bitmap *bm; if (!bdrv_dirty_bitmap_get_persistence(bitmap) || - bdrv_dirty_bitmap_readonly(bitmap) || bdrv_dirty_bitmap_inconsistent(bitmap)) { continue; } + if (bdrv_dirty_bitmap_readonly(bitmap)) { + /* + * Store the bitmap in the associated Qcow2Bitmap so it + * can be released later + */ + bm = find_bitmap_by_name(bm_list, name); + if (bm) { + bm->dirty_bitmap = bitmap; + } + continue; + } + need_write = true; if (check_constraints_on_bitmap(bs, name, granularity, errp) < 0) { @@ -1618,7 +1629,9 @@ void qcow2_store_persistent_dirty_bitmaps(BlockDriverState *bs, /* allocate clusters and store bitmaps */ QSIMPLEQ_FOREACH(bm, bm_list, entry) { - if (bm->dirty_bitmap == NULL) { + BdrvDirtyBitmap *bitmap = bm->dirty_bitmap; + + if (bitmap == NULL || bdrv_dirty_bitmap_readonly(bitmap)) { continue; } @@ -1641,6 +1654,7 @@ void qcow2_store_persistent_dirty_bitmaps(BlockDriverState *bs, g_free(tb); } +success: if (release_stored) { QSIMPLEQ_FOREACH(bm, bm_list, entry) { if (bm->dirty_bitmap == NULL) { @@ -1651,13 +1665,14 @@ void qcow2_store_persistent_dirty_bitmaps(BlockDriverState *bs, } } -success: bitmap_list_free(bm_list); return; fail: QSIMPLEQ_FOREACH(bm, bm_list, entry) { - if (bm->dirty_bitmap == NULL || bm->table.offset == 0) { + if (bm->dirty_bitmap == NULL || bm->table.offset == 0 || + bdrv_dirty_bitmap_readonly(bm->dirty_bitmap)) + { continue; }