From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43) id 1LPx2c-0002HW-R9 for qemu-devel@nongnu.org; Thu, 22 Jan 2009 05:44:07 -0500 Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43) id 1LPx2a-0002En-9a for qemu-devel@nongnu.org; Thu, 22 Jan 2009 05:44:04 -0500 Received: from [199.232.76.173] (port=37242 helo=monty-python.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1LPx2Z-0002Ef-GJ for qemu-devel@nongnu.org; Thu, 22 Jan 2009 05:44:03 -0500 Received: from mx2.redhat.com ([66.187.237.31]:58655) by monty-python.gnu.org with esmtp (Exim 4.60) (envelope-from ) id 1LPx2Y-0000pG-S8 for qemu-devel@nongnu.org; Thu, 22 Jan 2009 05:44:03 -0500 Received: from int-mx2.corp.redhat.com (int-mx2.corp.redhat.com [172.16.27.26]) by mx2.redhat.com (8.13.8/8.13.8) with ESMTP id n0MAi2YJ014805 for ; Thu, 22 Jan 2009 05:44:02 -0500 From: Uri Lublin Date: Thu, 22 Jan 2009 12:43:51 +0200 Message-Id: <1232621035-4951-2-git-send-email-uril@redhat.com> In-Reply-To: <1232621035-4951-1-git-send-email-uril@redhat.com> References: <1232621035-4951-1-git-send-email-uril@redhat.com> Subject: [Qemu-devel] [PATCH 1/5 v2] block-qcow2: keep highest allocated byte Reply-To: qemu-devel@nongnu.org List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: Uri Lublin We want to know the highest written offset for qcow2 images. This gives a pretty good (and easy to calculate) estimation to how much more allocation can be done for the block device. It can be usefull for allocating more diskspace for that image (if possible, e.g. lvm) before we run out-of-disk-space Signed-off-by: Uri Lublin --- block-qcow2.c | 34 ++++++++++++++++++++++++++++++++++ 1 files changed, 34 insertions(+), 0 deletions(-) diff --git a/block-qcow2.c b/block-qcow2.c index d4556ef..e016e8f 100644 --- a/block-qcow2.c +++ b/block-qcow2.c @@ -143,6 +143,9 @@ typedef struct BDRVQcowState { uint32_t crypt_method_header; AES_KEY aes_encrypt_key; AES_KEY aes_decrypt_key; + + int64_t highest_alloc; /* highest cluester allocated (in clusters) */ + uint64_t snapshots_offset; int snapshots_size; int nb_snapshots; @@ -170,6 +173,8 @@ static void free_clusters(BlockDriverState *bs, #ifdef DEBUG_ALLOC static void check_refcounts(BlockDriverState *bs); #endif +static void scan_refcount(BlockDriverState *bs, int64_t *high); + static int qcow_probe(const uint8_t *buf, int buf_size, const char *filename) { @@ -278,6 +283,8 @@ static int qcow_open(BlockDriverState *bs, const char *filename, int flags) if (refcount_init(bs) < 0) goto fail; + scan_refcount(bs, &s->highest_alloc); + /* read the backing file name */ if (header.backing_file_offset != 0) { len = header.backing_file_size; @@ -2206,6 +2213,29 @@ static int load_refcount_block(BlockDriverState *bs, return 0; } +static void scan_refcount(BlockDriverState *bs, int64_t *high) +{ + BDRVQcowState *s = bs->opaque; + int64_t refcnt_index, cluster_index, cluster_end, h = 0; + + for (refcnt_index=0; refcnt_index < s->refcount_table_size; refcnt_index++){ + if (s->refcount_table[refcnt_index] == 0) { + continue; + } + cluster_index = refcnt_index << (s->cluster_bits - REFCOUNT_SHIFT); + cluster_end = (refcnt_index + 1) << (s->cluster_bits - REFCOUNT_SHIFT); + for ( ; cluster_index < cluster_end; cluster_index++) { + if (get_refcount(bs, cluster_index) == 0) + /* do nothing -- reserved for free counting */; + else + h = cluster_index; + } + } + + if (high) + *high = (h+1); +} + static int get_refcount(BlockDriverState *bs, int64_t cluster_index) { BDRVQcowState *s = bs->opaque; @@ -2246,6 +2276,10 @@ retry: size, (s->free_cluster_index - nb_clusters) << s->cluster_bits); #endif + + if (s->highest_alloc < s->free_cluster_index) + s->highest_alloc = s->free_cluster_index; + return (s->free_cluster_index - nb_clusters) << s->cluster_bits; } -- 1.6.0.6