From c00716beb30ba996bd6fdfd5f41bb07e4414144f Mon Sep 17 00:00:00 2001 From: Eric Blake Date: Fri, 7 Jul 2017 07:44:58 -0500 Subject: block: Minimize raw use of bds->total_sectors bdrv_is_allocated_above() was relying on intermediate->total_sectors, which is a field that can have stale contents depending on the value of intermediate->has_variable_length. An audit shows that we are safe (we were first calling through bdrv_co_get_block_status() which in turn calls bdrv_nb_sectors() and therefore just refreshed the current length), but it's nicer to favor our accessor functions to avoid having to repeat such an audit, even if it means refresh_total_sectors() is called more frequently. Suggested-by: John Snow Signed-off-by: Eric Blake Reviewed-by: Manos Pitsidianakis Reviewed-by: Jeff Cody Reviewed-by: John Snow Signed-off-by: Kevin Wolf --- block/io.c | 14 ++++++-------- 1 file changed, 6 insertions(+), 8 deletions(-) (limited to 'block/io.c') diff --git a/block/io.c b/block/io.c index 6656d7fe3e..aad7fd30a4 100644 --- a/block/io.c +++ b/block/io.c @@ -1947,6 +1947,7 @@ int bdrv_is_allocated_above(BlockDriverState *top, intermediate = top; while (intermediate && intermediate != base) { int64_t pnum_inter; + int64_t size_inter; int psectors_inter; ret = bdrv_is_allocated(intermediate, sector_num * BDRV_SECTOR_SIZE, @@ -1962,15 +1963,12 @@ int bdrv_is_allocated_above(BlockDriverState *top, return 1; } - /* - * [sector_num, nb_sectors] is unallocated on top but intermediate - * might have - * - * [sector_num+x, nr_sectors] allocated. - */ + size_inter = bdrv_nb_sectors(intermediate); + if (size_inter < 0) { + return size_inter; + } if (n > psectors_inter && - (intermediate == top || - sector_num + psectors_inter < intermediate->total_sectors)) { + (intermediate == top || sector_num + psectors_inter < size_inter)) { n = psectors_inter; } -- cgit v1.2.1