From patchwork Tue Jul 31 16:51:47 2012 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Robert Wang X-Patchwork-Id: 174291 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 1F5992C009B for ; Wed, 1 Aug 2012 03:21:10 +1000 (EST) Received: from localhost ([::1]:36721 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1SwFhH-0003vm-Pd for incoming@patchwork.ozlabs.org; Tue, 31 Jul 2012 12:53:27 -0400 Received: from eggs.gnu.org ([208.118.235.92]:35370) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1SwFgP-0001fY-Rj for qemu-devel@nongnu.org; Tue, 31 Jul 2012 12:52:36 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1SwFgM-0004Kx-NO for qemu-devel@nongnu.org; Tue, 31 Jul 2012 12:52:33 -0400 Received: from mail-gg0-f173.google.com ([209.85.161.173]:42547) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1SwFgM-0004Kc-8u for qemu-devel@nongnu.org; Tue, 31 Jul 2012 12:52:30 -0400 Received: by ggnp1 with SMTP id p1so6076801ggn.4 for ; Tue, 31 Jul 2012 09:52:29 -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=zNVwb40smce1v8Afa6twaAQLVlQiVQyeGLtxVuAaabA=; b=MoBfzsHya6+EbU1iBcXY1aMn2SJZsFWisa+gGRbT/ESfPQpBv7WGRwsVOrpTkdju9v rx7mY5oSqGYzpVnJltbDUjOfBdU5obhmeNTNA+CxGIOtT3DTxQRg8lC8APdaNHS6lwq7 bXsMbu1ANw2mmOavJaKRrKRtcVIyL8SrtZ7VLl2asGQEiDB8t1u4uqubPuQ3I4j2mKM4 PETBNgKgucisuj7GpbftMjlVYE0GCx/0ao2dRSgoThvnjwT64Hodi5j51gSF2wSIBQi3 GCgYPskS+cK1rOkdGnER1sODoUURN2jpfJh3D+G3ZeUAXSpR2aVuJHqBYl3dP4hG7bMm 3Rrw== Received: by 10.50.6.163 with SMTP id c3mr2567324iga.35.1343753549231; Tue, 31 Jul 2012 09:52:29 -0700 (PDT) Received: from localhost.localdomain ([202.108.130.138]) by mx.google.com with ESMTPS id uq6sm3025753igb.14.2012.07.31.09.52.26 (version=TLSv1/SSLv3 cipher=OTHER); Tue, 31 Jul 2012 09:52:28 -0700 (PDT) From: Dong Xu Wang To: qemu-devel@nongnu.org Date: Wed, 1 Aug 2012 00:51:47 +0800 Message-Id: <1343753510-24661-3-git-send-email-wdongxu@linux.vnet.ibm.com> X-Mailer: git-send-email 1.7.1 In-Reply-To: <1343753510-24661-1-git-send-email-wdongxu@linux.vnet.ibm.com> References: <1343753510-24661-1-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: 209.85.161.173 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 | 206 +++++++++++++++++ block/add-cow.c | 599 +++++++++++++++++++++++++++++++++++++++++++++++++ block/add-cow.h | 101 +++++++++ block_int.h | 2 + 5 files changed, 909 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..5d5e8a4 --- /dev/null +++ b/block/add-cow-cache.c @@ -0,0 +1,206 @@ +/* + * 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) +{ + AddCowCache *c; + int i; + + c = g_malloc0(sizeof(*c)); + c->size = num_tables; + c->entries = g_malloc0(sizeof(*c->entries) * num_tables); + 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_PAGE_SIZE * s->header.header_pages_size + 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; + BDRVAddCowState *s = bs->opaque; + + 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, + s->header.header_pages_size * ADD_COW_PAGE_SIZE + 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; +} diff --git a/block/add-cow.c b/block/add-cow.c new file mode 100644 index 0000000..5f6b708 --- /dev/null +++ b/block/add-cow.c @@ -0,0 +1,599 @@ +/* + * 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 void add_cow_header_le_to_cpu(const AddCowHeader *le, AddCowHeader *cpu) +{ + cpu->magic = le64_to_cpu(le->magic); + cpu->version = le32_to_cpu(le->version); + + cpu->backing_filename_offset = le32_to_cpu(le->backing_filename_offset); + cpu->backing_filename_size = le32_to_cpu(le->backing_filename_size); + + cpu->image_filename_offset = le32_to_cpu(le->image_filename_offset); + cpu->image_filename_size = le32_to_cpu(le->image_filename_size); + + cpu->features = le64_to_cpu(le->features); + cpu->optional_features = le64_to_cpu(le->optional_features); + cpu->header_pages_size = le32_to_cpu(le->header_pages_size); +} + +static void add_cow_header_cpu_to_le(const AddCowHeader *cpu, AddCowHeader *le) +{ + le->magic = cpu_to_le64(cpu->magic); + le->version = cpu_to_le32(cpu->version); + + le->backing_filename_offset = cpu_to_le32(cpu->backing_filename_offset); + le->backing_filename_size = cpu_to_le32(cpu->backing_filename_size); + + le->image_filename_offset = cpu_to_le32(cpu->image_filename_offset); + le->image_filename_size = cpu_to_le32(cpu->image_filename_size); + + le->features = cpu_to_le64(cpu->features); + le->optional_features = cpu_to_le64(cpu->optional_features); + le->header_pages_size = cpu_to_le32(cpu->header_pages_size); +} + +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 = { + .magic = ADD_COW_MAGIC, + .version = ADD_COW_VERSION, + .features = 0, + .optional_features = 0, + .header_pages_size = ADD_COW_DEFAULT_PAGE_SIZE, + }; + AddCowHeader le_header; + int64_t backing_len = 0; + const char *backing_filename = NULL; + const char *backing_fmt = NULL; + const char *image_filename = NULL; + const char *image_format = NULL; + BlockDriverState *bs, *image_bs = NULL, *backing_bs = NULL; + BlockDriver *drv = bdrv_find_format("add-cow"); + int ret; + + while (options && options->name) { + if (!strcmp(options->name, BLOCK_OPT_SIZE)) { + backing_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; + } else if (!strcmp(options->name, BLOCK_OPT_IMAGE_FORMAT)) { + image_format = options->value.s; + } + options++; + } + + if (backing_filename) { + header.features |= ADD_COW_F_BACKING_FILE; + header.backing_filename_offset = sizeof(header) + 16 * 2; + header.backing_filename_size = strlen(backing_filename); + + if (!backing_fmt) { + backing_bs = bdrv_new("image"); + ret = bdrv_open(backing_bs, backing_filename, BDRV_O_RDWR + | BDRV_O_CACHE_WB, NULL); + if (ret < 0) { + return ret; + } + backing_fmt = bdrv_get_format_name(backing_bs); + bdrv_delete(backing_bs); + } + } else { + header.features |= ADD_COW_F_All_ALLOCATED; + } + + if (image_filename) { + header.features |= ADD_COW_F_IMAGE_FILE; + header.image_filename_offset = + sizeof(header) + 16 * 2 + header.backing_filename_size; + header.image_filename_size = strlen(image_filename); + } else { + error_report("image_file should be given."); + return -EINVAL; + } + + if (backing_filename && !strcmp(backing_filename, image_filename)) { + error_report("Error: Trying to create an image with the " + "same backing file name as the image file name"); + return -EINVAL; + } + + if (!strcmp(filename, image_filename)) { + error_report("Error: Trying to create an image with the " + "same filename as the image file name"); + return -EINVAL; + } + + if (header.image_filename_offset + header.image_filename_size + > ADD_COW_PAGE_SIZE * ADD_COW_DEFAULT_PAGE_SIZE) { + error_report("image_file name or backing_file name too long."); + return -ENOSPC; + } + + ret = bdrv_file_open(&image_bs, image_filename, BDRV_O_RDWR); + 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; + } + add_cow_header_cpu_to_le(&header, &le_header); + ret = bdrv_pwrite(bs, 0, &le_header, sizeof(le_header)); + if (ret < 0) { + bdrv_delete(bs); + return ret; + } + + ret = bdrv_pwrite(bs, sizeof(le_header), backing_fmt ? backing_fmt : "", + backing_fmt ? sizeof(backing_fmt) : 0); + if (ret < 0) { + bdrv_delete(bs); + return ret; + } + + ret = bdrv_pwrite(bs, sizeof(le_header) + 16, + image_format ? image_format : "raw", + image_format ? sizeof(image_format) : sizeof("raw")); + if (ret < 0) { + bdrv_delete(bs); + return ret; + } + + if (backing_filename) { + 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, backing_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; + BlockDriverState *backing_bs = NULL; + int ret; + int sector_per_byte; + BDRVAddCowState *s = bs->opaque; + AddCowHeader le_header; + + ret = bdrv_pread(bs->file, 0, &le_header, sizeof(le_header)); + if (ret != sizeof(s->header)) { + goto fail; + } + + add_cow_header_le_to_cpu(&le_header, &s->header); + + if (le64_to_cpu(s->header.magic) != ADD_COW_MAGIC) { + ret = -EINVAL; + goto fail; + } + + if (s->header.version != ADD_COW_VERSION) { + char version[64]; + snprintf(version, sizeof(version), "ADD-COW version %d", + s->header.version); + qerror_report(QERR_UNKNOWN_BLOCK_FORMAT_FEATURE, + bs->device_name, "add-cow", version); + ret = -ENOTSUP; + goto fail; + } + + if (s->header.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 ((s->header.features & ADD_COW_F_IMAGE_FILE) == 0) { + ret = -ENOTSUP; + goto fail; + } + + if ((s->header.features & ADD_COW_F_All_ALLOCATED) == 0) { + ret = bdrv_read_string(bs->file, sizeof(s->header), + 15, s->backing_file_format, + sizeof(s->backing_file_format)); + if (ret < 0) { + goto fail; + } + } + + ret = bdrv_read_string(bs->file, sizeof(s->header) + 16, + 15, s->image_file_format, + sizeof(s->image_file_format)); + if (ret < 0) { + goto fail; + } + + if ((s->header.features & ADD_COW_F_All_ALLOCATED) == 0) { + 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; + } + + if (s->header.features & ADD_COW_F_All_ALLOCATED) { + bs->total_sectors = bdrv_getlength(s->image_hd) >> 9; + } else { + backing_bs = bdrv_new("image"); + ret = bdrv_open(backing_bs, bs->backing_file, BDRV_O_RDWR + | BDRV_O_CACHE_WB, NULL); + if (ret < 0) { + return ret; + } + bs->total_sectors = bdrv_getlength(backing_bs) >> 9; + bdrv_delete(backing_bs); + } + + 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; + s->bitmap_cache = + add_cow_cache_create(bs, ADD_COW_CACHE_SIZE); + + 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) +{ + BDRVAddCowState *s = bs->opaque; + int changed; + + if (nb_sectors == 0) { + *num_same = 0; + return 0; + } + + if (s->header.features & ADD_COW_F_All_ALLOCATED) { + *num_same = nb_sectors - 1; + return 1; + } + 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_concat(&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_concat(&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, 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; + + 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; + } + if ((s->header.features & ADD_COW_F_All_ALLOCATED) == 0) { + /* 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) { + goto fail; + } + if ((table[i / 8] & (1 << (i % 8))) == 0) { + table[i / 8] |= (1 << (i % 8)); + add_cow_cache_entry_mark_dirty(s->bitmap_cache, table); + } + } + } + ret = 0; +fail: + 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; + uint32_t bitmap_pos = s->header.header_pages_size * ADD_COW_PAGE_SIZE; + int64_t bitmap_size = + (size / BDRV_SECTOR_SIZE + sector_per_byte - 1) / sector_per_byte; + + ret = bdrv_truncate(bs->file, bitmap_pos + bitmap_size); + if (ret < 0) { + return ret; + } + 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); + return ret; +} + +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_BACKING_FMT, + .type = OPT_STRING, + .help = "Image format of the base image" + }, + { + .name = BLOCK_OPT_IMAGE_FILE, + .type = OPT_STRING, + .help = "File name of a image file" + }, + { + .name = BLOCK_OPT_IMAGE_FORMAT, + .type = OPT_STRING, + .help = "Image format of the image file" + }, + { 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_os = 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..738249c --- /dev/null +++ b/block/add-cow.h @@ -0,0 +1,101 @@ +/* + * 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_IMAGE_FILE = 0x02, + ADD_COW_F_All_ALLOCATED = 0X04, + ADD_COW_FEATURE_MASK = ADD_COW_F_BACKING_FILE | \ + ADD_COW_F_IMAGE_FILE | \ + ADD_COW_F_All_ALLOCATED, + + 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_PAGE_SIZE = 4096, + ADD_COW_DEFAULT_PAGE_SIZE = 1 +}; + +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; + uint64_t optional_features; + uint32_t header_pages_size; +} 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; +} AddCowCache; + +typedef struct BDRVAddCowState { + BlockDriverState *image_hd; + CoMutex lock; + int cluster_size; + AddCowCache *bitmap_cache; + uint64_t bitmap_size; + AddCowHeader header; + char backing_file_format[16]; + char image_file_format[16]; +} 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); +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); +#endif diff --git a/block_int.h b/block_int.h index d72317f..8f8bb2b 100644 --- a/block_int.h +++ b/block_int.h @@ -51,6 +51,8 @@ #define BLOCK_OPT_PREALLOC "preallocation" #define BLOCK_OPT_SUBFMT "subformat" #define BLOCK_OPT_COMPAT_LEVEL "compat" +#define BLOCK_OPT_IMAGE_FILE "image_file" +#define BLOCK_OPT_IMAGE_FORMAT "image_format" typedef struct BdrvTrackedRequest BdrvTrackedRequest;