From patchwork Wed Jun 13 14:36:26 2012 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Robert Wang X-Patchwork-Id: 164701 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 A2CD8B7024 for ; Thu, 14 Jun 2012 00:38:01 +1000 (EST) Received: from localhost ([::1]:41172 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Seohr-0006bP-Hh for incoming@patchwork.ozlabs.org; Wed, 13 Jun 2012 10:37:59 -0400 Received: from eggs.gnu.org ([208.118.235.92]:35417) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Seoh8-0004qe-Rh for qemu-devel@nongnu.org; Wed, 13 Jun 2012 10:37:22 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Seoh0-0001um-Qv for qemu-devel@nongnu.org; Wed, 13 Jun 2012 10:37:14 -0400 Received: from mail-pz0-f45.google.com ([209.85.210.45]:50041) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Seoh0-0001rj-Dc for qemu-devel@nongnu.org; Wed, 13 Jun 2012 10:37:06 -0400 Received: by mail-pz0-f45.google.com with SMTP id n2so62418dad.4 for ; Wed, 13 Jun 2012 07:37:05 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=sender:from:to:cc:subject:date:message-id:x-mailer:in-reply-to :references; bh=FgUBNyR6+ulCyjN9zEvwLVuBScZjThiF92+2QfE8fFU=; b=ppQyrE939Pp34FDqphaeG2lNu90ZO4ZJsMIa/cBwiAM2hhJM16fN1IzVumzjwKVRBW YTpNiaDv7OXqmp1YmbPkngspOMP0kxbCMhLrHsYSY1lBj0JbPpVKaQ168BL7TYetpdRh pt9XXMY2fdUJp/aCv68A/KYvqeQFTQaCb1VA9QWhd2UBTAVwf8/H0Zk7G4e8KykfYUZM e6gYCXpFKc3AuhcHf4cp5uIQb2itIEeipviu+LXsHy64hO4uzen7uhgdL2Wu6KdqEogg TIWZ1E6FJseTnxmARPmlaA/2BJCx4qMxRb7DD1Zzg613cW0Q1pCfo0d2UAUQB+WTzgMt 0J0A== Received: by 10.68.231.8 with SMTP id tc8mr48786615pbc.140.1339598225275; Wed, 13 Jun 2012 07:37:05 -0700 (PDT) Received: from localhost.localdomain ([202.108.130.138]) by mx.google.com with ESMTPS id tj4sm5945250pbc.33.2012.06.13.07.37.02 (version=TLSv1/SSLv3 cipher=OTHER); Wed, 13 Jun 2012 07:37:04 -0700 (PDT) From: Dong Xu Wang To: qemu-devel@nongnu.org Date: Wed, 13 Jun 2012 22:36:26 +0800 Message-Id: <1339598189-17933-3-git-send-email-wdongxu@linux.vnet.ibm.com> X-Mailer: git-send-email 1.7.1 In-Reply-To: <1339598189-17933-1-git-send-email-wdongxu@linux.vnet.ibm.com> References: <1339598189-17933-1-git-send-email-wdongxu@linux.vnet.ibm.com> X-detected-operating-system: by eggs.gnu.org: Genre and OS details not recognized. X-Received-From: 209.85.210.45 Cc: kwolf@redhat.com, Dong Xu Wang Subject: [Qemu-devel] [PATCH 3/6] add-cow file format 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 is the implementation code for add-cow file format. Because image_file might be very huge, then we can't read entire bitmap into memory, we must use a cache. Since qcow-cache.c has implemted cache code, we can create our cache code based on it. Signed-off-by: Dong Xu Wang --- block/Makefile.objs | 1 + block/add-cow-cache.c | 218 ++++++++++++++++++++++ block/add-cow.c | 488 +++++++++++++++++++++++++++++++++++++++++++++++++ block/add-cow.h | 95 ++++++++++ block_int.h | 1 + 5 files changed, 803 insertions(+), 0 deletions(-) create mode 100644 block/add-cow-cache.c create mode 100644 block/add-cow.c create mode 100644 block/add-cow.h diff --git a/block/Makefile.objs b/block/Makefile.objs index b5754d3..357a3b1 100644 --- a/block/Makefile.objs +++ b/block/Makefile.objs @@ -2,6 +2,7 @@ block-obj-y += raw.o cow.o qcow.o vdi.o vmdk.o cloop.o dmg.o bochs.o vpc.o vvfat block-obj-y += qcow2.o qcow2-refcount.o qcow2-cluster.o qcow2-snapshot.o qcow2-cache.o block-obj-y += qed.o qed-gencb.o qed-l2-cache.o qed-table.o qed-cluster.o block-obj-y += qed-check.o +block-obj-y += add-cow.o add-cow-cache.o block-obj-y += parallels.o nbd.o blkdebug.o sheepdog.o blkverify.o block-obj-y += stream.o block-obj-$(CONFIG_WIN32) += raw-win32.o diff --git a/block/add-cow-cache.c b/block/add-cow-cache.c new file mode 100644 index 0000000..b4b1546 --- /dev/null +++ b/block/add-cow-cache.c @@ -0,0 +1,218 @@ +/* + * Cache For QEMU ADD-COW Disk Format + * + * Copyright IBM, Corp. 2012 + * + * Authors: + * Dong Xu Wang + * + * This file is based on qcow2-cache.c, see its copyrights below: + * + * L2/refcount table cache for the QCOW2 format + * + * Copyright (c) 2010 Kevin Wolf + * + * Permission is hereby granted, free of charge, to any person obtaining a copy + * of this software and associated documentation files (the "Software"), to deal + * in the Software without restriction, including without limitation the rights + * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell + * copies of the Software, and to permit persons to whom the Software is + * furnished to do so, subject to the following conditions: + * + * The above copyright notice and this permission notice shall be included in + * all copies or substantial portions of the Software. + * + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL + * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, + * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN + * THE SOFTWARE. + */ + +#include "block_int.h" +#include "qemu-common.h" +#include "add-cow.h" + +AddCowCache *add_cow_cache_create(BlockDriverState *bs, int num_tables, + bool writethrough) +{ + AddCowCache *c; + int i; + + c = g_malloc0(sizeof(*c)); + c->size = num_tables; + c->entries = g_malloc0(sizeof(*c->entries) * num_tables); + c->writethrough = writethrough; + c->entry_size = ADD_COW_CACHE_ENTRY_SIZE; + + for (i = 0; i < c->size; i++) { + c->entries[i].table = qemu_blockalign(bs, c->entry_size); + c->entries[i].offset = -1; + } + + return c; +} + +int add_cow_cache_destroy(BlockDriverState *bs, AddCowCache *c) +{ + int i; + + for (i = 0; i < c->size; i++) { + qemu_vfree(c->entries[i].table); + } + + g_free(c->entries); + g_free(c); + + return 0; +} + +static int add_cow_cache_entry_flush(BlockDriverState *bs, + AddCowCache *c, + int i) +{ + BDRVAddCowState *s = bs->opaque; + int ret = 0; + + if (!c->entries[i].dirty || -1 == c->entries[i].offset) { + return ret; + } + + ret = bdrv_pwrite(bs->file, + ADD_COW_BITMAP_POS + c->entries[i].offset, + c->entries[i].table, + MIN(c->entry_size, s->bitmap_size - c->entries[i].offset)); + if (ret < 0) { + return ret; + } + + c->entries[i].dirty = false; + + return 0; +} + +int add_cow_cache_flush(BlockDriverState *bs, AddCowCache *c) +{ + BDRVAddCowState *s = bs->opaque; + int result = 0; + int ret; + int i; + + ret = bdrv_flush(s->image_hd); + if (ret < 0) { + return result; + } + + for (i = 0; i < c->size; i++) { + ret = add_cow_cache_entry_flush(bs, c, i); + if (ret < 0 && result != -ENOSPC) { + result = ret; + } + } + + if (result == 0) { + ret = bdrv_flush(bs->file); + if (ret < 0) { + result = ret; + } + } + + return result; +} + +static int add_cow_cache_find_entry_to_replace(AddCowCache *c) +{ + int i; + int min_count = INT_MAX; + int min_index = -1; + + + for (i = 0; i < c->size; i++) { + if (c->entries[i].cache_hits < min_count) { + min_index = i; + min_count = c->entries[i].cache_hits; + } + + c->entries[i].cache_hits /= 2; + } + + if (min_index == -1) { + abort(); + } + return min_index; +} + +static int add_cow_cache_do_get(BlockDriverState *bs, AddCowCache *c, + uint64_t offset, void **table) +{ + int i, ret; + + for (i = 0; i < c->size; i++) { + if (c->entries[i].offset == offset) { + goto found; + } + } + + i = add_cow_cache_find_entry_to_replace(c); + if (i < 0) { + return i; + } + + ret = add_cow_cache_entry_flush(bs, c, i); + if (ret < 0) { + return ret; + } + c->entries[i].offset = -1; + ret = bdrv_pread(bs->file, ADD_COW_BITMAP_POS + offset, + c->entries[i].table, c->entry_size); + if (ret < 0) { + return ret; + } + + c->entries[i].cache_hits = 32; + c->entries[i].offset = offset; + +found: + c->entries[i].cache_hits++; + *table = c->entries[i].table; + + return 0; +} + +int add_cow_cache_get(BlockDriverState *bs, AddCowCache *c, uint64_t sector_num, + void **table) +{ + /* each byte in bitmap indicates 8 * SECTORS_PER_CLUSTER clusters */ + uint64_t offset = offset_in_bitmap(sector_num) & (~(c->entry_size - 1)); + return add_cow_cache_do_get(bs, c, offset, table); +} + +void add_cow_cache_entry_mark_dirty(AddCowCache *c, void *table) +{ + int i; + + for (i = 0; i < c->size; i++) { + if (c->entries[i].table == table) { + goto found; + } + } + abort(); + +found: + c->entries[i].dirty = true; +} + +bool add_cow_cache_set_writethrough(BlockDriverState *bs, AddCowCache *c, + bool enable) +{ + bool old = c->writethrough; + + if (!old && enable) { + add_cow_cache_flush(bs, c); + } + + c->writethrough = enable; + return old; +} diff --git a/block/add-cow.c b/block/add-cow.c new file mode 100644 index 0000000..f8bc299 --- /dev/null +++ b/block/add-cow.c @@ -0,0 +1,488 @@ +/* + * QEMU ADD-COW Disk Format + * + * Copyright IBM, Corp. 2012 + * + * Authors: + * Dong Xu Wang + * + * This work is licensed under the terms of the GNU LGPL, version 2 or later. + * See the COPYING.LIB file in the top-level directory. + * + */ + +#include "qemu-common.h" +#include "block_int.h" +#include "module.h" +#include "add-cow.h" + +static int add_cow_probe(const uint8_t *buf, int buf_size, const char *filename) +{ + const AddCowHeader *header = (const AddCowHeader *)buf; + + if (le64_to_cpu(header->magic) == ADD_COW_MAGIC && + le32_to_cpu(header->version) == ADD_COW_VERSION) { + return 100; + } else { + return 0; + } +} + +static int add_cow_create(const char *filename, QEMUOptionParameter *options) +{ + AddCowHeader header; + int64_t image_len = 0; + const char *backing_filename = NULL; + const char *backing_fmt = NULL; + const char *image_filename = NULL; + int ret; + BlockDriverState *bs, *image_bs = NULL; + BlockDriver *drv = bdrv_find_format("add-cow"); + + while (options && options->name) { + if (!strcmp(options->name, BLOCK_OPT_SIZE)) { + image_len = options->value.n; + } else if (!strcmp(options->name, BLOCK_OPT_BACKING_FILE)) { + backing_filename = options->value.s; + } else if (!strcmp(options->name, BLOCK_OPT_BACKING_FMT)) { + backing_fmt = options->value.s; + } else if (!strcmp(options->name, BLOCK_OPT_IMAGE_FILE)) { + image_filename = options->value.s; + } + options++; + } + memset(&header, 0, sizeof(header)); + header.magic = cpu_to_le64(ADD_COW_MAGIC); + header.version = cpu_to_le32(ADD_COW_VERSION); + header.features = cpu_to_le64(ADD_COW_F_BACKING_FILE); + + if (backing_filename) { + header.features |= ADD_COW_F_BACKING_FILE; + header.backing_filename_offset = sizeof(header); + header.backing_filename_size = strlen(backing_filename); + + if (backing_fmt && strcmp(backing_fmt, "raw") == 0) { + header.features |= ADD_COW_F_BACKING_FORMAT_NO_PROBE; + pstrcpy(bs->backing_format, sizeof(bs->backing_format), "raw"); + } + } else { + error_report("backing_file should be given."); + return -EINVAL; + } + + if (image_filename) { + header.image_filename_offset = + sizeof(header) + header.backing_filename_size; + header.image_filename_size = strlen(image_filename); + } else { + error_report("image_file should be given."); + return -EINVAL; + } + + if (header.image_filename_offset + header.image_filename_size > ADD_COW_BITMAP_POS) { + error_report("image_file name or backing_file name too long."); + return -ENOSPC; + } + + ret = bdrv_file_open(&image_bs, image_filename, BDRV_O_RDWR + | BDRV_O_CACHE_WB); + if (ret < 0) { + return ret; + } + bdrv_delete(image_bs); + + ret = bdrv_create_file(filename, NULL); + if (ret < 0) { + return ret; + } + + ret = bdrv_file_open(&bs, filename, BDRV_O_RDWR); + if (ret < 0) { + return ret; + } + + ret = bdrv_pwrite(bs, 0, &header, sizeof(header)); + if (ret < 0) { + bdrv_delete(bs); + return ret; + } + + ret = bdrv_pwrite(bs, + header.backing_filename_offset, + backing_filename, + header.backing_filename_size); + if (ret < 0) { + bdrv_delete(bs); + return ret; + } + + ret = bdrv_pwrite(bs, + header.image_filename_offset, + image_filename, + header.image_filename_size); + if (ret < 0) { + bdrv_delete(bs); + return ret; + } + + ret = bdrv_open(bs, filename, BDRV_O_RDWR | BDRV_O_NO_FLUSH, drv); + if (ret < 0) { + bdrv_delete(bs); + return ret; + } + + ret = bdrv_truncate(bs, image_len); + bdrv_delete(bs); + return ret; +} + +static int add_cow_open(BlockDriverState *bs, int flags) +{ + char image_filename[ADD_COW_FILE_LEN]; + char tmp_name[ADD_COW_FILE_LEN]; + BlockDriver *image_drv = NULL; + int ret; + bool writethrough; + int sector_per_byte; + BDRVAddCowState *s = bs->opaque; + uint64_t features; + + ret = bdrv_pread(bs->file, 0, &s->header, sizeof(s->header)); + if (ret != sizeof(s->header)) { + goto fail; + } + + if (le64_to_cpu(s->header.magic) != ADD_COW_MAGIC) { + ret = -EINVAL; + goto fail; + } + if (le32_to_cpu(s->header.version) != ADD_COW_VERSION) { + char version[64]; + snprintf(version, sizeof(version), "ADD-COW version %d", + le32_to_cpu(s->header.version)); + qerror_report(QERR_UNKNOWN_BLOCK_FORMAT_FEATURE, + bs->device_name, "add-cow", version); + ret = -ENOTSUP; + goto fail; + } + features = le64_to_cpu(s->header.features); + if (features & ~ADD_COW_FEATURE_MASK) { + char buf[64]; + snprintf(buf, sizeof(buf), "%" PRIx64, + s->header.features & ~ADD_COW_FEATURE_MASK); + qerror_report(QERR_UNKNOWN_BLOCK_FORMAT_FEATURE, + bs->device_name, "add-cow", buf); + return -ENOTSUP; + } + if ((features & ADD_COW_F_BACKING_FILE) == 0) { + /* Now, only with backing_file is supported */ + ret = -ENOTSUP; + goto fail; + } + ret = bdrv_read_string(bs->file, s->header.backing_filename_offset, + s->header.backing_filename_size, bs->backing_file, + sizeof(bs->backing_file)); + if (ret < 0) { + goto fail; + } + ret = bdrv_read_string(bs->file, s->header.image_filename_offset, + s->header.image_filename_size, tmp_name, + sizeof(tmp_name)); + if (ret < 0) { + goto fail; + } + s->image_hd = bdrv_new(""); + if (path_has_protocol(image_filename)) { + pstrcpy(image_filename, sizeof(image_filename), tmp_name); + } else { + path_combine(image_filename, sizeof(image_filename), + bs->filename, tmp_name); + } + ret = bdrv_open(s->image_hd, image_filename, flags, image_drv); + if (ret < 0) { + bdrv_delete(s->image_hd); + goto fail; + } + bs->total_sectors = bdrv_getlength(s->image_hd) >> 9; + s->cluster_size = ADD_COW_CLUSTER_SIZE; + sector_per_byte = SECTORS_PER_CLUSTER * 8; + s->bitmap_size = + (bs->total_sectors + sector_per_byte - 1) / sector_per_byte; + writethrough = ((flags & BDRV_O_CACHE_WB) == 0); + s->bitmap_cache = + add_cow_cache_create(bs, ADD_COW_CACHE_SIZE, writethrough); + + qemu_co_mutex_init(&s->lock); + return 0; +fail: + if (s->bitmap_cache) { + add_cow_cache_destroy(bs, s->bitmap_cache); + } + return ret; +} + +static void add_cow_close(BlockDriverState *bs) +{ + BDRVAddCowState *s = bs->opaque; + add_cow_cache_destroy(bs, s->bitmap_cache); + bdrv_delete(s->image_hd); +} + +static bool is_allocated(BlockDriverState *bs, int64_t sector_num) +{ + BDRVAddCowState *s = bs->opaque; + int64_t cluster_num = sector_num / SECTORS_PER_CLUSTER; + uint8_t *table = NULL; + int ret = add_cow_cache_get(bs, s->bitmap_cache, + sector_num, (void **)&table); + + if (ret < 0) { + return ret; + } + return table[cluster_num / 8 % ADD_COW_CACHE_ENTRY_SIZE] + & (1 << (cluster_num % 8)); +} + +static coroutine_fn int add_cow_is_allocated(BlockDriverState *bs, + int64_t sector_num, int nb_sectors, int *num_same) +{ + int changed; + + if (nb_sectors == 0) { + *num_same = 0; + return 0; + } + changed = is_allocated(bs, sector_num); + + for (*num_same = 1; *num_same < nb_sectors; (*num_same)++) { + if (is_allocated(bs, sector_num + *num_same) != changed) { + break; + } + } + return changed; +} + +static coroutine_fn int add_cow_co_readv(BlockDriverState *bs, + int64_t sector_num, int remaining_sectors, QEMUIOVector *qiov) +{ + BDRVAddCowState *s = bs->opaque; + int cur_nr_sectors; + uint64_t bytes_done = 0; + QEMUIOVector hd_qiov; + int n, ret = 0; + + qemu_iovec_init(&hd_qiov, qiov->niov); + qemu_co_mutex_lock(&s->lock); + while (remaining_sectors != 0) { + cur_nr_sectors = remaining_sectors; + if (add_cow_is_allocated(bs, sector_num, cur_nr_sectors, &n)) { + cur_nr_sectors = n; + qemu_iovec_reset(&hd_qiov); + qemu_iovec_copy(&hd_qiov, qiov, bytes_done, + cur_nr_sectors * BDRV_SECTOR_SIZE); + qemu_co_mutex_unlock(&s->lock); + ret = bdrv_co_readv(s->image_hd, sector_num, n, &hd_qiov); + qemu_co_mutex_lock(&s->lock); + if (ret < 0) { + goto fail; + } + } else { + cur_nr_sectors = n; + if (bs->backing_hd) { + qemu_iovec_reset(&hd_qiov); + qemu_iovec_copy(&hd_qiov, qiov, bytes_done, + cur_nr_sectors * BDRV_SECTOR_SIZE); + qemu_co_mutex_unlock(&s->lock); + ret = bdrv_co_readv(bs->backing_hd, sector_num, + n, &hd_qiov); + qemu_co_mutex_lock(&s->lock); + if (ret < 0) { + goto fail; + } + } else { + qemu_iovec_memset(&hd_qiov, 0, + BDRV_SECTOR_SIZE * cur_nr_sectors); + } + } + remaining_sectors -= cur_nr_sectors; + sector_num += cur_nr_sectors; + bytes_done += cur_nr_sectors * BDRV_SECTOR_SIZE; + } +fail: + qemu_co_mutex_unlock(&s->lock); + qemu_iovec_destroy(&hd_qiov); + return ret; +} + +static int coroutine_fn copy_sectors(BlockDriverState *bs, + int n_start, int n_end) +{ + BDRVAddCowState *s = bs->opaque; + QEMUIOVector qiov; + struct iovec iov; + int n, ret; + + n = n_end - n_start; + if (n <= 0) { + return 0; + } + + iov.iov_len = n * BDRV_SECTOR_SIZE; + iov.iov_base = qemu_blockalign(bs, iov.iov_len); + + qemu_iovec_init_external(&qiov, &iov, 1); + + ret = bdrv_co_readv(bs->backing_hd, n_start, n, &qiov); + if (ret < 0) { + goto out; + } + ret = bdrv_co_writev(s->image_hd, n_start, n, &qiov); + if (ret < 0) { + goto out; + } + + ret = 0; +out: + qemu_vfree(iov.iov_base); + return ret; +} + +static coroutine_fn int add_cow_co_writev(BlockDriverState *bs, + int64_t sector_num, int remaining_sectors, QEMUIOVector *qiov) +{ + BDRVAddCowState *s = bs->opaque; + int ret = 0, i; + QEMUIOVector hd_qiov; + uint8_t *table; + bool changed = false; + + qemu_co_mutex_lock(&s->lock); + qemu_iovec_init(&hd_qiov, qiov->niov); + ret = bdrv_co_writev(s->image_hd, + sector_num, + remaining_sectors, qiov); + + if (ret < 0) { + goto fail; + } + /* Copy content of unmodified sectors */ + if (!is_cluster_head(sector_num) && !is_allocated(bs, sector_num)) { + ret = copy_sectors(bs, sector_num & ~(SECTORS_PER_CLUSTER - 1), + sector_num); + if (ret < 0) { + goto fail; + } + } + + if (!is_cluster_tail(sector_num + remaining_sectors - 1) + && !is_allocated(bs, sector_num + remaining_sectors - 1)) { + ret = copy_sectors(bs, sector_num + remaining_sectors, + ((sector_num + remaining_sectors) | (SECTORS_PER_CLUSTER - 1)) + 1); + if (ret < 0) { + goto fail; + } + } + + for (i = sector_num / SECTORS_PER_CLUSTER; + i <= (sector_num + remaining_sectors - 1) / SECTORS_PER_CLUSTER; + i++) { + ret = add_cow_cache_get(bs, s->bitmap_cache, + i * SECTORS_PER_CLUSTER, (void **)&table); + if (ret < 0) { + return ret; + } + if ((table[i / 8] & (1 << (i % 8))) == 0) { + table[i / 8] |= (1 << (i % 8)); + changed = true; + add_cow_cache_entry_mark_dirty(s->bitmap_cache, table); + } + + } + ret = 0; +fail: + if (changed) { + ret = add_cow_cache_flush(bs, s->bitmap_cache); + } + qemu_co_mutex_unlock(&s->lock); + qemu_iovec_destroy(&hd_qiov); + return ret; +} + +static int bdrv_add_cow_truncate(BlockDriverState *bs, int64_t size) +{ + BDRVAddCowState *s = bs->opaque; + int sector_per_byte = SECTORS_PER_CLUSTER * 8; + int ret; + int64_t bitmap_size = + (size / BDRV_SECTOR_SIZE + sector_per_byte - 1) / sector_per_byte; + + ret = bdrv_truncate(bs->file, + ADD_COW_BITMAP_POS + bitmap_size); + if (ret < 0) { + return ret; + } + bdrv_truncate(s->image_hd, size); + return 0; +} + +static coroutine_fn int add_cow_co_flush(BlockDriverState *bs) +{ + BDRVAddCowState *s = bs->opaque; + int ret; + + qemu_co_mutex_lock(&s->lock); + ret = add_cow_cache_flush(bs, s->bitmap_cache); + qemu_co_mutex_unlock(&s->lock); + if (ret < 0) { + return ret; + } + + return bdrv_co_flush(bs->file); +} + +static QEMUOptionParameter add_cow_create_options[] = { + { + .name = BLOCK_OPT_SIZE, + .type = OPT_SIZE, + .help = "Virtual disk size" + }, + { + .name = BLOCK_OPT_BACKING_FILE, + .type = OPT_STRING, + .help = "File name of a base image" + }, + { + .name = BLOCK_OPT_IMAGE_FILE, + .type = OPT_STRING, + .help = "File name of a image file" + }, + { + .name = BLOCK_OPT_BACKING_FMT, + .type = OPT_STRING, + .help = "Image format of the base image" + }, + { NULL } +}; + +static BlockDriver bdrv_add_cow = { + .format_name = "add-cow", + .instance_size = sizeof(BDRVAddCowState), + .bdrv_probe = add_cow_probe, + .bdrv_open = add_cow_open, + .bdrv_close = add_cow_close, + .bdrv_create = add_cow_create, + .bdrv_co_readv = add_cow_co_readv, + .bdrv_co_writev = add_cow_co_writev, + .bdrv_truncate = bdrv_add_cow_truncate, + .bdrv_co_is_allocated = add_cow_is_allocated, + + .create_options = add_cow_create_options, + .bdrv_co_flush_to_disk = add_cow_co_flush, +}; + +static void bdrv_add_cow_init(void) +{ + bdrv_register(&bdrv_add_cow); +} + +block_init(bdrv_add_cow_init); diff --git a/block/add-cow.h b/block/add-cow.h new file mode 100644 index 0000000..f83f8e7 --- /dev/null +++ b/block/add-cow.h @@ -0,0 +1,95 @@ +/* + * QEMU ADD-COW Disk Format + * + * Copyright IBM, Corp. 2012 + * + * Authors: + * Dong Xu Wang + * + * This work is licensed under the terms of the GNU LGPL, version 2 or later. + * See the COPYING.LIB file in the top-level directory. + * + */ + +#ifndef BLOCK_ADD_COW_H +#define BLOCK_ADD_COW_H + +enum { + ADD_COW_F_BACKING_FILE = 0x01, + ADD_COW_F_BACKING_FORMAT_NO_PROBE = 0x02, + ADD_COW_FEATURE_MASK = ADD_COW_F_BACKING_FILE | + ADD_COW_F_BACKING_FORMAT_NO_PROBE, + + ADD_COW_MAGIC = (((uint64_t)'A' << 56) | ((uint64_t)'D' << 48) | \ + ((uint64_t)'D' << 40) | ((uint64_t)'_' << 32) | \ + ((uint64_t)'C' << 24) | ((uint64_t)'O' << 16) | \ + ((uint64_t)'W' << 8) | 0xFF), + ADD_COW_VERSION = 1, + ADD_COW_FILE_LEN = 1024, + ADD_COW_CACHE_SIZE = 16, + ADD_COW_CACHE_ENTRY_SIZE = 65536, + ADD_COW_CLUSTER_SIZE = 65536, + SECTORS_PER_CLUSTER = (ADD_COW_CLUSTER_SIZE / BDRV_SECTOR_SIZE), + ADD_COW_BITMAP_POS = 4096 +}; + +typedef struct AddCowHeader { + uint64_t magic; + uint32_t version; + uint32_t backing_filename_offset; + uint32_t backing_filename_size; + uint32_t image_filename_offset; + uint32_t image_filename_size; + uint64_t features; +} QEMU_PACKED AddCowHeader; + +typedef struct AddCowCachedTable { + void *table; + int64_t offset; + bool dirty; + int cache_hits; +} AddCowCachedTable; + +typedef struct AddCowCache { + AddCowCachedTable *entries; + int entry_size; + int size; + bool writethrough; +} AddCowCache; + +typedef struct BDRVAddCowState { + BlockDriverState *image_hd; + CoMutex lock; + int cluster_size; + AddCowCache *bitmap_cache; + uint64_t bitmap_size; + AddCowHeader header; +} BDRVAddCowState; + +/* Convert sector_num to offset in bitmap */ +static inline int64_t offset_in_bitmap(int64_t sector_num) +{ + int64_t cluster_num = sector_num / SECTORS_PER_CLUSTER; + return cluster_num / 8; +} + +static inline bool is_cluster_head(int64_t sector_num) +{ + return sector_num % SECTORS_PER_CLUSTER == 0; +} + +static inline bool is_cluster_tail(int64_t sector_num) +{ + return (sector_num + 1) % SECTORS_PER_CLUSTER == 0; +} + +AddCowCache *add_cow_cache_create(BlockDriverState *bs, int num_tables, + bool writethrough); +int add_cow_cache_destroy(BlockDriverState *bs, AddCowCache *c); +void add_cow_cache_entry_mark_dirty(AddCowCache *c, void *table); +int add_cow_cache_get(BlockDriverState *bs, AddCowCache *c, uint64_t offset, + void **table); +int add_cow_cache_flush(BlockDriverState *bs, AddCowCache *c); +bool add_cow_cache_set_writethrough(BlockDriverState *bs, AddCowCache *c, + bool enable); +#endif diff --git a/block_int.h b/block_int.h index 3d4abc6..a0be58c 100644 --- a/block_int.h +++ b/block_int.h @@ -51,6 +51,7 @@ #define BLOCK_OPT_PREALLOC "preallocation" #define BLOCK_OPT_SUBFMT "subformat" #define BLOCK_OPT_COMPAT_LEVEL "compat" +#define BLOCK_OPT_IMAGE_FILE "image_file" typedef struct BdrvTrackedRequest BdrvTrackedRequest;