From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:36605) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1d8pAF-0001yP-0P for qemu-devel@nongnu.org; Thu, 11 May 2017 10:34:00 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1d8pAB-00075g-2S for qemu-devel@nongnu.org; Thu, 11 May 2017 10:33:59 -0400 From: Kevin Wolf Date: Thu, 11 May 2017 16:32:27 +0200 Message-Id: <1494513181-7900-25-git-send-email-kwolf@redhat.com> In-Reply-To: <1494513181-7900-1-git-send-email-kwolf@redhat.com> References: <1494513181-7900-1-git-send-email-kwolf@redhat.com> Subject: [Qemu-devel] [PULL 24/58] qcow2: Fix preallocation size formula List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-block@nongnu.org Cc: kwolf@redhat.com, stefanha@redhat.com, qemu-devel@nongnu.org From: Max Reitz When calculating the number of reftable entries, we should actually use the number of refblocks and not (wrongly[1]) re-calculate it. [1] "Wrongly" means: Dividing the number of clusters by the number of entries per refblock and rounding down instead of up. Reported-by: Eric Blake Signed-off-by: Max Reitz Reviewed-by: Eric Blake Signed-off-by: Kevin Wolf --- block/qcow2.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) diff --git a/block/qcow2.c b/block/qcow2.c index 1c26977..8caf800 100644 --- a/block/qcow2.c +++ b/block/qcow2.c @@ -2139,7 +2139,7 @@ static int qcow2_create2(const char *filename, int64_t total_size, * too, as long as the bulk is allocated here). Therefore, using * floating point arithmetic is fine. */ int64_t meta_size = 0; - uint64_t nreftablee, nrefblocke, nl1e, nl2e; + uint64_t nreftablee, nrefblocke, nl1e, nl2e, refblock_count; int64_t aligned_total_size = align_offset(total_size, cluster_size); int refblock_bits, refblock_size; /* refcount entry size in bytes */ @@ -2182,11 +2182,12 @@ static int qcow2_create2(const char *filename, int64_t total_size, nrefblocke = (aligned_total_size + meta_size + cluster_size) / (cluster_size - rces - rces * sizeof(uint64_t) / cluster_size); - meta_size += DIV_ROUND_UP(nrefblocke, refblock_size) * cluster_size; + refblock_count = DIV_ROUND_UP(nrefblocke, refblock_size); + meta_size += refblock_count * cluster_size; /* total size of refcount tables */ - nreftablee = nrefblocke / refblock_size; - nreftablee = align_offset(nreftablee, cluster_size / sizeof(uint64_t)); + nreftablee = align_offset(refblock_count, + cluster_size / sizeof(uint64_t)); meta_size += nreftablee * sizeof(uint64_t); qemu_opt_set_number(opts, BLOCK_OPT_SIZE, -- 1.8.3.1