Set the inconsistent bit on load instead of rejecting such bitmaps. There is no way to un-set it; the only option is to delete it.
Obvervations: - bitmap loading does not need to update the header for in_use bitmaps. - inconsistent bitmaps don't need to have their data loaded; they're glorified corruption sentinels. - bitmap saving does not need to save inconsistent bitmaps back to disk. - bitmap reopening DOES need to drop the readonly flag from inconsistent bitmaps to allow reopening of qcow2 files with non-qemu-owned bitmaps being eventually flushed back to disk. Signed-off-by: John Snow <js...@redhat.com> --- block/qcow2-bitmap.c | 77 +++++++++++++++++++++++--------------------- 1 file changed, 40 insertions(+), 37 deletions(-) diff --git a/block/qcow2-bitmap.c b/block/qcow2-bitmap.c index 3ee524da4b..d1cc11da88 100644 --- a/block/qcow2-bitmap.c +++ b/block/qcow2-bitmap.c @@ -343,9 +343,15 @@ static BdrvDirtyBitmap *load_bitmap(BlockDriverState *bs, uint32_t granularity; BdrvDirtyBitmap *bitmap = NULL; + granularity = 1U << bm->granularity_bits; + bitmap = bdrv_create_dirty_bitmap(bs, granularity, bm->name, errp); + if (bitmap == NULL) { + goto fail; + } + if (bm->flags & BME_FLAG_IN_USE) { - error_setg(errp, "Bitmap '%s' is in use", bm->name); - goto fail; + /* Data is unusable, skip loading it */ + return bitmap; } ret = bitmap_table_load(bs, &bm->table, &bitmap_table); @@ -356,12 +362,6 @@ static BdrvDirtyBitmap *load_bitmap(BlockDriverState *bs, goto fail; } - granularity = 1U << bm->granularity_bits; - bitmap = bdrv_create_dirty_bitmap(bs, granularity, bm->name, errp); - if (bitmap == NULL) { - goto fail; - } - ret = load_bitmap_data(bs, bitmap_table, bm->table.size, bitmap); if (ret < 0) { error_setg_errno(errp, -ret, "Could not read bitmap '%s' from image", @@ -949,6 +949,7 @@ bool qcow2_load_dirty_bitmaps(BlockDriverState *bs, Error **errp) Qcow2Bitmap *bm; GSList *created_dirty_bitmaps = NULL; bool header_updated = false; + bool needs_update = false; if (s->nb_bitmaps == 0) { /* No bitmaps - nothing to do */ @@ -962,23 +963,27 @@ bool qcow2_load_dirty_bitmaps(BlockDriverState *bs, Error **errp) } QSIMPLEQ_FOREACH(bm, bm_list, entry) { - if (!(bm->flags & BME_FLAG_IN_USE)) { - BdrvDirtyBitmap *bitmap = load_bitmap(bs, bm, errp); - if (bitmap == NULL) { - goto fail; - } + BdrvDirtyBitmap *bitmap = load_bitmap(bs, bm, errp); + if (bitmap == NULL) { + goto fail; + } - if (!(bm->flags & BME_FLAG_AUTO)) { - bdrv_disable_dirty_bitmap(bitmap); - } - bdrv_dirty_bitmap_set_persistance(bitmap, true); + if (bm->flags & BME_FLAG_IN_USE) { + bdrv_dirty_bitmap_set_inconsistent(bitmap); + } else { + /* NB: updated flags only get written if can_write(bs) is true. */ bm->flags |= BME_FLAG_IN_USE; - created_dirty_bitmaps = - g_slist_append(created_dirty_bitmaps, bitmap); + needs_update = true; } + if (!(bm->flags & BME_FLAG_AUTO)) { + bdrv_disable_dirty_bitmap(bitmap); + } + bdrv_dirty_bitmap_set_persistance(bitmap, true); + created_dirty_bitmaps = + g_slist_append(created_dirty_bitmaps, bitmap); } - if (created_dirty_bitmaps != NULL) { + if (needs_update) { if (can_write(bs)) { /* in_use flags must be updated */ int ret = update_ext_header_and_dir_in_place(bs, bm_list); @@ -1112,23 +1117,21 @@ int qcow2_reopen_bitmaps_rw_hint(BlockDriverState *bs, bool *header_updated, } QSIMPLEQ_FOREACH(bm, bm_list, entry) { - if (!(bm->flags & BME_FLAG_IN_USE)) { - BdrvDirtyBitmap *bitmap = bdrv_find_dirty_bitmap(bs, bm->name); - if (bitmap == NULL) { - continue; - } - - if (!bdrv_dirty_bitmap_readonly(bitmap)) { - error_setg(errp, "Bitmap %s is not readonly but not marked" - "'IN_USE' in the image. Something went wrong," - "all the bitmaps may be corrupted", bm->name); - ret = -EINVAL; - goto out; - } + BdrvDirtyBitmap *bitmap = bdrv_find_dirty_bitmap(bs, bm->name); + if (bitmap == NULL) { + continue; + } - bm->flags |= BME_FLAG_IN_USE; - ro_dirty_bitmaps = g_slist_append(ro_dirty_bitmaps, bitmap); + if (!bdrv_dirty_bitmap_readonly(bitmap)) { + error_setg(errp, "Bitmap %s was loaded prior to rw-reopen, but was " + "not marked as readonly. This is a bug, something went " + "wrong. All of the bitmaps may be corrupted", bm->name); + ret = -EINVAL; + goto out; } + + bm->flags |= BME_FLAG_IN_USE; + ro_dirty_bitmaps = g_slist_append(ro_dirty_bitmaps, bitmap); } if (ro_dirty_bitmaps != NULL) { @@ -1424,8 +1427,8 @@ void qcow2_store_persistent_dirty_bitmaps(BlockDriverState *bs, Error **errp) Qcow2Bitmap *bm; if (!bdrv_dirty_bitmap_get_persistance(bitmap) || - bdrv_dirty_bitmap_readonly(bitmap)) - { + bdrv_dirty_bitmap_readonly(bitmap) || + bdrv_dirty_bitmap_inconsistent(bitmap)) { continue; } -- 2.17.2