We've previously fixed several places where we failed to account
for possible errors from bdrv_nb_sectors(). Fix another one by
making bdrv_dirty_bitmap_truncate() take the new size from the
caller instead of querying itself; then adjust the sole caller
bdrv_truncate() to pass the size just determined by a successful
resize, or to skip the bitmap resize on failure, thus avoiding
sizing the bitmaps to -1. This also fixes a bug where not all
failure paths in bdrv_truncate() would set errp.
Note that bdrv_truncate() is still a bit awkward. We may want
to revisit it later and clean up things to better guarantee that
a resize attempt either fails cleanly up front, or cannot fail
after guest-visible changes have been made (if temporary changes
are made, then they need to be cleanly rolled back). But that
is a task for another day; for now, the goal is the bare minimum
fix to ensure that just bdrv_dirty_bitmap_truncate() cannot fail.
Signed-off-by: Eric Blake <address@hidden>
---
v10: always resize bitmap as before [John], enhance commit message to
point out errp bugfix [Vladimir]
v9: skip only bdrv_dirty_bitmap_truncate on error [Fam]
v8: retitle and rework to avoid possibility of secondary failure [John]
v7: new patch [Kevin]
---
include/block/dirty-bitmap.h | 2 +-
block.c | 16 +++++++++++-----
block/dirty-bitmap.c | 6 +++---
3 files changed, 15 insertions(+), 9 deletions(-)
diff --git a/include/block/dirty-bitmap.h b/include/block/dirty-bitmap.h
index 8fd842eac9..7a27590047 100644
--- a/include/block/dirty-bitmap.h
+++ b/include/block/dirty-bitmap.h
@@ -83,7 +83,7 @@ int64_t bdrv_dirty_iter_next(BdrvDirtyBitmapIter *iter);
void bdrv_set_dirty_iter(BdrvDirtyBitmapIter *hbi, int64_t sector_num);
int64_t bdrv_get_dirty_count(BdrvDirtyBitmap *bitmap);
int64_t bdrv_get_meta_dirty_count(BdrvDirtyBitmap *bitmap);
-void bdrv_dirty_bitmap_truncate(BlockDriverState *bs);
+void bdrv_dirty_bitmap_truncate(BlockDriverState *bs, int64_t bytes);
bool bdrv_dirty_bitmap_readonly(const BdrvDirtyBitmap *bitmap);
bool bdrv_has_readonly_bitmaps(BlockDriverState *bs);
bool bdrv_dirty_bitmap_get_autoload(const BdrvDirtyBitmap *bitmap);
diff --git a/block.c b/block.c
index 528cda7b2c..ef5af81f66 100644
--- a/block.c
+++ b/block.c
@@ -3545,12 +3545,18 @@ int bdrv_truncate(BdrvChild *child, int64_t offset,
PreallocMode prealloc,
assert(!(bs->open_flags & BDRV_O_INACTIVE));
ret = drv->bdrv_truncate(bs, offset, prealloc, errp);
- if (ret == 0) {
- ret = refresh_total_sectors(bs, offset >> BDRV_SECTOR_BITS);
- bdrv_dirty_bitmap_truncate(bs);
- bdrv_parent_cb_resize(bs);
- atomic_inc(&bs->write_gen);
+ if (ret < 0) {
+ return ret;
}
+ ret = refresh_total_sectors(bs, offset >> BDRV_SECTOR_BITS);
+ if (ret < 0) {
+ error_setg_errno(errp, -ret, "Could not refresh total sector count");
+ } else {
+ offset = bs->total_sectors * BDRV_SECTOR_SIZE;
+ }
+ bdrv_dirty_bitmap_truncate(bs, offset);
+ bdrv_parent_cb_resize(bs);
+ atomic_inc(&bs->write_gen);
return ret;
}
diff --git a/block/dirty-bitmap.c b/block/dirty-bitmap.c
index 42a55e4a4b..ee164fb518 100644
--- a/block/dirty-bitmap.c
+++ b/block/dirty-bitmap.c
@@ -1,7 +1,7 @@
/*
* Block Dirty Bitmap
*
- * Copyright (c) 2016 Red Hat. Inc
+ * Copyright (c) 2016-2017 Red Hat. Inc
*
* Permission is hereby granted, free of charge, to any person obtaining a
copy
* of this software and associated documentation files (the "Software"), to
deal
@@ -302,10 +302,10 @@ BdrvDirtyBitmap
*bdrv_reclaim_dirty_bitmap(BlockDriverState *bs,
* Truncates _all_ bitmaps attached to a BDS.
* Called with BQL taken.
*/
-void bdrv_dirty_bitmap_truncate(BlockDriverState *bs)
+void bdrv_dirty_bitmap_truncate(BlockDriverState *bs, int64_t bytes)
{
BdrvDirtyBitmap *bitmap;
- uint64_t size = bdrv_nb_sectors(bs);
+ int64_t size = DIV_ROUND_UP(bytes, BDRV_SECTOR_SIZE);
bdrv_dirty_bitmaps_lock(bs);
QLIST_FOREACH(bitmap, &bs->dirty_bitmaps, list) {