From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:41682) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1dEIX0-0008Tu-GE for qemu-devel@nongnu.org; Fri, 26 May 2017 12:56:07 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1dEIWz-0003jA-Go for qemu-devel@nongnu.org; Fri, 26 May 2017 12:56:06 -0400 From: Max Reitz Date: Fri, 26 May 2017 18:55:11 +0200 Message-Id: <20170526165518.7580-10-mreitz@redhat.com> In-Reply-To: <20170526165518.7580-1-mreitz@redhat.com> References: <20170526165518.7580-1-mreitz@redhat.com> Subject: [Qemu-devel] [PATCH v3 09/16] block/qcow2: Generalize preallocate() List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-block@nongnu.org Cc: qemu-devel@nongnu.org, Max Reitz , Kevin Wolf , Stefan Hajnoczi This patch adds two new parameters to the preallocate() function so we will be able to use it not just for preallocating a new image but also for preallocated image growth. The offset parameter allows the caller to specify a virtual offset from which to start preallocating. For newly created images this is always 0, but for preallocating growth this will be the old image length. The new_length parameter specifies the supposed new length of the image (basically the "end offset" for preallocation). During image truncation, bdrv_getlength() will return the old image length so we cannot rely on its return value then. Signed-off-by: Max Reitz --- block/qcow2.c | 17 ++++++++++++----- 1 file changed, 12 insertions(+), 5 deletions(-) diff --git a/block/qcow2.c b/block/qcow2.c index 3d4f36d..df953aa 100644 --- a/block/qcow2.c +++ b/block/qcow2.c @@ -2035,17 +2035,24 @@ static int qcow2_change_backing_file(BlockDriverState *bs, return qcow2_update_header(bs); } -static int preallocate(BlockDriverState *bs) +/** + * Preallocates metadata structures for data clusters between @offset (in the + * guest disk) and @new_length (which is thus generally the new guest disk + * size). + * + * Returns: 0 on success, -errno on failure. + */ +static int preallocate(BlockDriverState *bs, + uint64_t offset, uint64_t new_length) { uint64_t bytes; - uint64_t offset; uint64_t host_offset = 0; unsigned int cur_bytes; int ret; QCowL2Meta *meta; - bytes = bdrv_getlength(bs); - offset = 0; + assert(offset <= new_length); + bytes = new_length - offset; while (bytes) { cur_bytes = MIN(bytes, INT_MAX); @@ -2384,7 +2391,7 @@ static int qcow2_create2(const char *filename, int64_t total_size, if (prealloc != PREALLOC_MODE_OFF) { BDRVQcow2State *s = blk_bs(blk)->opaque; qemu_co_mutex_lock(&s->lock); - ret = preallocate(blk_bs(blk)); + ret = preallocate(blk_bs(blk), 0, total_size); qemu_co_mutex_unlock(&s->lock); if (ret < 0) { error_setg_errno(errp, -ret, "Could not preallocate metadata"); -- 2.9.4