From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:35811) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1WCQ2X-0003UZ-3u for qemu-devel@nongnu.org; Sun, 09 Feb 2014 03:47:05 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1WCQ2S-00019I-QN for qemu-devel@nongnu.org; Sun, 09 Feb 2014 03:47:01 -0500 Received: from mx1.redhat.com ([209.132.183.28]:2425) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1WCQ2S-00019C-HN for qemu-devel@nongnu.org; Sun, 09 Feb 2014 03:46:56 -0500 From: Kevin Wolf Date: Sun, 9 Feb 2014 09:46:23 +0100 Message-Id: <1391935590-12264-12-git-send-email-kwolf@redhat.com> In-Reply-To: <1391935590-12264-1-git-send-email-kwolf@redhat.com> References: <1391935590-12264-1-git-send-email-kwolf@redhat.com> Subject: [Qemu-devel] [PULL 11/18] qcow2: check for NULL l2meta List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: anthony@codemonkey.ws Cc: kwolf@redhat.com, qemu-devel@nongnu.org From: Hu Tao In the case of a metadata preallocation with a large cluster size, qcow2_alloc_cluster_offset() can allocate nothing and returns a NULL l2meta. This patch checks for it and link2 l2 with only valid l2meta. Replace 9 and 512 with BDRV_SECTOR_BITS, BDRV_SECTOR_SIZE respectively while at the function. Signed-off-by: Hu Tao Reviewed-by: Max Reitz Reviewed-by: Benoit Canet Signed-off-by: Kevin Wolf --- block/qcow2.c | 31 ++++++++++++++++--------------- 1 file changed, 16 insertions(+), 15 deletions(-) diff --git a/block/qcow2.c b/block/qcow2.c index a274d5f..0b4335c 100644 --- a/block/qcow2.c +++ b/block/qcow2.c @@ -1404,34 +1404,34 @@ static int preallocate(BlockDriverState *bs) int ret; QCowL2Meta *meta; - nb_sectors = bdrv_getlength(bs) >> 9; + nb_sectors = bdrv_getlength(bs) >> BDRV_SECTOR_BITS; offset = 0; while (nb_sectors) { - num = MIN(nb_sectors, INT_MAX >> 9); + num = MIN(nb_sectors, INT_MAX >> BDRV_SECTOR_BITS); ret = qcow2_alloc_cluster_offset(bs, offset, &num, &host_offset, &meta); if (ret < 0) { return ret; } - ret = qcow2_alloc_cluster_link_l2(bs, meta); - if (ret < 0) { - qcow2_free_any_clusters(bs, meta->alloc_offset, meta->nb_clusters, - QCOW2_DISCARD_NEVER); - return ret; - } - - /* There are no dependent requests, but we need to remove our request - * from the list of in-flight requests */ if (meta != NULL) { + ret = qcow2_alloc_cluster_link_l2(bs, meta); + if (ret < 0) { + qcow2_free_any_clusters(bs, meta->alloc_offset, + meta->nb_clusters, QCOW2_DISCARD_NEVER); + return ret; + } + + /* There are no dependent requests, but we need to remove our + * request from the list of in-flight requests */ QLIST_REMOVE(meta, next_in_flight); } /* TODO Preallocate data if requested */ nb_sectors -= num; - offset += num << 9; + offset += num << BDRV_SECTOR_BITS; } /* @@ -1440,9 +1440,10 @@ static int preallocate(BlockDriverState *bs) * EOF). Extend the image to the last allocated sector. */ if (host_offset != 0) { - uint8_t buf[512]; - memset(buf, 0, 512); - ret = bdrv_write(bs->file, (host_offset >> 9) + num - 1, buf, 1); + uint8_t buf[BDRV_SECTOR_SIZE]; + memset(buf, 0, BDRV_SECTOR_SIZE); + ret = bdrv_write(bs->file, (host_offset >> BDRV_SECTOR_BITS) + num - 1, + buf, 1); if (ret < 0) { return ret; } -- 1.8.1.4