@@ -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
new file mode 100644
@@ -0,0 +1,206 @@
+/*
+ * Cache For QEMU ADD-COW Disk Format
+ *
+ * Copyright IBM, Corp. 2012
+ *
+ * Authors:
+ * Dong Xu Wang <wdongxu@linux.vnet.ibm.com>
+ *
+ * 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 <kwolf@redhat.com>
+ *
+ * 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;
+}
new file mode 100644
@@ -0,0 +1,599 @@
+/*
+ * QEMU ADD-COW Disk Format
+ *
+ * Copyright IBM, Corp. 2012
+ *
+ * Authors:
+ * Dong Xu Wang <wdongxu@linux.vnet.ibm.com>
+ *
+ * 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);
new file mode 100644
@@ -0,0 +1,101 @@
+/*
+ * QEMU ADD-COW Disk Format
+ *
+ * Copyright IBM, Corp. 2012
+ *
+ * Authors:
+ * Dong Xu Wang <wdongxu@linux.vnet.ibm.com>
+ *
+ * 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
@@ -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;
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 <wdongxu@linux.vnet.ibm.com> --- 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