From 1b6cc579ded4f9d7923d9d59147512edd623f4c0 Mon Sep 17 00:00:00 2001 From: Eric Blake Date: Mon, 25 Sep 2017 09:55:11 -0500 Subject: [PATCH] dirty-bitmap: Avoid size query failure during truncate 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 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 Reviewed-by: Vladimir Sementsov-Ogievskiy Reviewed-by: John Snow Reviewed-by: Fam Zheng Signed-off-by: Kevin Wolf --- block.c | 16 +++++++++++----- block/dirty-bitmap.c | 6 +++--- include/block/dirty-bitmap.h | 2 +- 3 files changed, 15 insertions(+), 9 deletions(-) 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) { 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); -- 2.11.4.GIT