From patchwork Wed Mar 6 14:48:43 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jeff Cody X-Patchwork-Id: 225515 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from lists.gnu.org (lists.gnu.org [208.118.235.17]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (Client did not present a certificate) by ozlabs.org (Postfix) with ESMTPS id 0FB352C037B for ; Thu, 7 Mar 2013 01:49:38 +1100 (EST) Received: from localhost ([::1]:40247 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1UDFey-0003wg-83 for incoming@patchwork.ozlabs.org; Wed, 06 Mar 2013 09:49:36 -0500 Received: from eggs.gnu.org ([208.118.235.92]:54189) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1UDFeI-0003fZ-CS for qemu-devel@nongnu.org; Wed, 06 Mar 2013 09:49:01 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1UDFeB-0002ha-8E for qemu-devel@nongnu.org; Wed, 06 Mar 2013 09:48:54 -0500 Received: from mx1.redhat.com ([209.132.183.28]:24081) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1UDFeB-0002hW-0Q for qemu-devel@nongnu.org; Wed, 06 Mar 2013 09:48:47 -0500 Received: from int-mx10.intmail.prod.int.phx2.redhat.com (int-mx10.intmail.prod.int.phx2.redhat.com [10.5.11.23]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id r26Emkuh006747 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK); Wed, 6 Mar 2013 09:48:46 -0500 Received: from localhost (ovpn-112-42.phx2.redhat.com [10.3.112.42]) by int-mx10.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id r26EmiOD004875 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES128-SHA bits=128 verify=NO); Wed, 6 Mar 2013 09:48:45 -0500 From: Jeff Cody To: qemu-devel@nongnu.org Date: Wed, 6 Mar 2013 09:48:43 -0500 Message-Id: <7aabf75e26ea1d60102fd0e1adfcd104aa3689c8.1362580930.git.jcody@redhat.com> In-Reply-To: References: X-Scanned-By: MIMEDefang 2.68 on 10.5.11.23 X-detected-operating-system: by eggs.gnu.org: GNU/Linux 3.x X-Received-From: 209.132.183.28 Cc: kwolf@redhat.com, sw@weilnetz.de, stefanha@redhat.com Subject: [Qemu-devel] [PATCH 7/7] block: add write support for VHDX images X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org This adds in write support for VHDX images. This supports writing to both dynamic and fixed VHDX images. Differencing images are still unsupported. Signed-off-by: Jeff Cody --- block/vhdx.c | 144 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++- 1 file changed, 142 insertions(+), 2 deletions(-) diff --git a/block/vhdx.c b/block/vhdx.c index 13d1e7f..316a5d8 100644 --- a/block/vhdx.c +++ b/block/vhdx.c @@ -165,6 +165,7 @@ typedef struct BDRVVHDXState { vhdx_bat_entry *bat; uint64_t bat_offset; + bool first_visible_write; ms_guid session_guid; @@ -782,6 +783,7 @@ static int vhdx_open(BlockDriverState *bs, int flags) int i; s->bat = NULL; + s->first_visible_write = true; qemu_co_mutex_init(&s->lock); @@ -829,7 +831,7 @@ static int vhdx_open(BlockDriverState *bs, int flags) vhdx_update_headers(bs, s, false); } - /* TODO: differencing files, write */ + /* TODO: differencing files */ return 0; fail: @@ -958,12 +960,150 @@ exit: return ret; } +/* + * Allocate a new payload block at the end of the file. + * + * Allocation will happen at 1MB alignment inside the file + * + * Returns the file offset start of the new payload block + */ +static int vhdx_allocate_block(BlockDriverState *bs, BDRVVHDXState *s, + uint64_t *new_offset) +{ + *new_offset = bdrv_getlength(bs->file); + + /* per the spec, the address for a block is in units of 1MB */ + if (*new_offset % (1024*1024)) { + *new_offset = ((*new_offset >> 20) + 1) << 20; /* round up to 1MB */ + } + return bdrv_truncate(bs->file, *new_offset + s->block_size); +} + +/* + * Update the BAT tablet entry with the new file offset, and the new entry + * state */ +static int vhdx_update_bat_table_entry(BlockDriverState *bs, BDRVVHDXState *s, + vhdx_sector_info *sinfo, int state) +{ + uint64_t bat_tmp; + uint64_t bat_entry_offset; + + /* The BAT entry is a uint64, with 44 bits for the file offset in units of + * 1MB, and 3 bits for the block state. */ + s->bat[sinfo->bat_idx] = ((sinfo->file_offset>>20) << + VHDX_BAT_FILE_OFF_BITS); + + s->bat[sinfo->bat_idx] |= state & VHDX_BAT_STATE_BIT_MASK; + bat_tmp = cpu_to_le64(s->bat[sinfo->bat_idx]); + bat_entry_offset = s->bat_offset + sinfo->bat_idx * sizeof(vhdx_bat_entry); + + return bdrv_pwrite_sync(bs->file, bat_entry_offset, &bat_tmp, + sizeof(vhdx_bat_entry)); +} static coroutine_fn int vhdx_co_writev(BlockDriverState *bs, int64_t sector_num, int nb_sectors, QEMUIOVector *qiov) { - return -ENOTSUP; + int ret = -ENOTSUP; + BDRVVHDXState *s = bs->opaque; + vhdx_sector_info sinfo; + uint64_t bytes_done = 0; + QEMUIOVector hd_qiov; + + qemu_iovec_init(&hd_qiov, qiov->niov); + + qemu_co_mutex_lock(&s->lock); + + /* Per the spec, on the first write of guest-visible data to the file the + * data write guid must be updated in the header */ + if (s->first_visible_write) { + s->first_visible_write = false; + vhdx_update_headers(bs, s, true); + } + + while (nb_sectors > 0) { + if (s->params.data_bits & VHDX_PARAMS_HAS_PARENT) { + /* not supported yet */ + ret = -ENOTSUP; + goto exit; + } else { + vhdx_block_translate(s, sector_num, nb_sectors, &sinfo); + + qemu_iovec_reset(&hd_qiov); + qemu_iovec_concat(&hd_qiov, qiov, bytes_done, sinfo.bytes_avail); + /* check the payload block state */ + switch (s->bat[sinfo.bat_idx] & VHDX_BAT_STATE_BIT_MASK) { + case PAYLOAD_BLOCK_ZERO: + /* in this case, we need to preserve zero writes for + * data that is not part of this write, so we must pad + * the rest of the buffer to zeroes */ + + /* if we are on a posix system with ftruncate() that extends + * a file, then it is zero-filled for us. On Win32, the raw + * layer uses SetFilePointer and SetFileEnd, which does not + * zero fill AFAIK */ + + /* TODO: queue another write of zero buffers if the host OS does + * not zero-fill on file extension */ + + /* fall through */ + case PAYLOAD_BLOCK_NOT_PRESENT: /* fall through */ + case PAYLOAD_BLOCK_UNMAPPED: /* fall through */ + case PAYLOAD_BLOCK_UNDEFINED: /* fall through */ + ret = vhdx_allocate_block(bs, s, &sinfo.file_offset); + if (ret < 0) { + goto exit; + } + /* once we support differencing files, this may also be + * partially present */ + /* update block state to the newly specified state */ + ret = vhdx_update_bat_table_entry(bs, s, &sinfo, + PAYLOAD_BLOCK_FULL_PRESENT); + if (ret < 0) { + goto exit; + } + /* since we just allocated a block, file_offset is the + * beginning of the payload block. It needs to be the + * write address, which includes the offset into the block */ + sinfo.file_offset += sinfo.block_offset; + /* fall through */ + case PAYLOAD_BLOCK_FULL_PRESENT: + /* if the file offset address is in the header zone, + * there is a problem */ + if (sinfo.file_offset < (1024*1024)) { + ret = -EFAULT; + goto exit; + } + /* block exists, so we can just overwrite it */ + qemu_co_mutex_unlock(&s->lock); + ret = bdrv_co_writev(bs->file, + sinfo.file_offset>>BDRV_SECTOR_BITS, + sinfo.sectors_avail, &hd_qiov); + qemu_co_mutex_lock(&s->lock); + if (ret < 0) { + goto exit; + } + break; + case PAYLOAD_BLOCK_PARTIALLY_PRESENT: + /* we don't yet support difference files, fall through + * to error */ + default: + ret = -EIO; + goto exit; + break; + } + + nb_sectors -= sinfo.sectors_avail; + sector_num += sinfo.sectors_avail; + bytes_done += sinfo.bytes_avail; + + } + } + +exit: + qemu_co_mutex_unlock(&s->lock); + return ret; }