From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:49854) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XpGa7-0007VU-JZ for qemu-devel@nongnu.org; Fri, 14 Nov 2014 08:06:37 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1XpGa1-0003HH-Fv for qemu-devel@nongnu.org; Fri, 14 Nov 2014 08:06:31 -0500 Received: from mx1.redhat.com ([209.132.183.28]:52631) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XpGa1-0003H2-8l for qemu-devel@nongnu.org; Fri, 14 Nov 2014 08:06:25 -0500 From: Max Reitz Date: Fri, 14 Nov 2014 14:05:54 +0100 Message-Id: <1415970374-16811-2-git-send-email-mreitz@redhat.com> In-Reply-To: <1415970374-16811-1-git-send-email-mreitz@redhat.com> References: <1415970374-16811-1-git-send-email-mreitz@redhat.com> Subject: [Qemu-devel] [PATCH v2 01/21] qcow2: Add two new fields to BDRVQcowState List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: Kevin Wolf , Peter Lieven , Stefan Hajnoczi , Max Reitz Add two new fields regarding refcount information (the bit width of every entry and the maximum refcount value) to the BDRVQcowState. Signed-off-by: Max Reitz Reviewed-by: Eric Blake --- block/qcow2-refcount.c | 2 +- block/qcow2.c | 9 +++++++++ block/qcow2.h | 2 ++ 3 files changed, 12 insertions(+), 1 deletion(-) diff --git a/block/qcow2-refcount.c b/block/qcow2-refcount.c index 9afdb40..6016211 100644 --- a/block/qcow2-refcount.c +++ b/block/qcow2-refcount.c @@ -584,7 +584,7 @@ static int QEMU_WARN_UNUSED_RESULT update_refcount(BlockDriverState *bs, refcount = be16_to_cpu(refcount_block[block_index]); refcount += addend; - if (refcount < 0 || refcount > 0xffff) { + if (refcount < 0 || refcount > s->refcount_max) { ret = -EINVAL; goto fail; } diff --git a/block/qcow2.c b/block/qcow2.c index d120494..f57aff9 100644 --- a/block/qcow2.c +++ b/block/qcow2.c @@ -684,6 +684,15 @@ static int qcow2_open(BlockDriverState *bs, QDict *options, int flags, goto fail; } s->refcount_order = header.refcount_order; + s->refcount_bits = 1 << s->refcount_order; + if (s->refcount_order < 6) { + s->refcount_max = (UINT64_C(1) << s->refcount_bits) - 1; + } else { + /* The above shift would overflow with s->refcount_bits == 64; + * furthermore, we do not want to use UINT64_MAX because refcounts will + * be passed around in int64_ts (negative values for -errno) */ + s->refcount_max = INT64_MAX; + } if (header.crypt_method > QCOW_CRYPT_AES) { error_setg(errp, "Unsupported encryption method: %" PRIu32, diff --git a/block/qcow2.h b/block/qcow2.h index 6e39a1b..4d8c902 100644 --- a/block/qcow2.h +++ b/block/qcow2.h @@ -258,6 +258,8 @@ typedef struct BDRVQcowState { int qcow_version; bool use_lazy_refcounts; int refcount_order; + int refcount_bits; + uint64_t refcount_max; bool discard_passthrough[QCOW2_DISCARD_MAX]; -- 1.9.3