On 09/25/2017 10:23 AM, Vladimir Sementsov-Ogievskiy wrote: > 25.09.2017 17:55, 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 > > nothing is skipped in this version
So much for me squashing in a change. If the maintainer is willing (Kevin, is this going through your tree?), we can reword that to: "...pass the size just determined by a successful resize, or to reuse the size given to the original truncate operation when refresh_total_sectors() was not able to confirm the actual size (the two sizes can potentially differ according to rounding constraints), 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> > > Reviewed-by: Vladimir Sementsov-Ogievskiy <vsement...@virtuozzo.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) { > > -- Eric Blake, Principal Software Engineer Red Hat, Inc. +1-919-301-3266 Virtualization: qemu.org | libvirt.org
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