On Mon, 09/25 09:55, Eric Blake wrote: > 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 <ebl...@redhat.com> > > --- > 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) { > -- > 2.13.5 >
Reviewed-by: Fam Zheng <f...@redhat.com>