add-cow file format core code. It use block-cache.c as cache code.
It lacks of snapshot_blkdev support.
v18->v19:
1) add aio parallel write support.
2) fix flush method.
v17-v18:
1) use error_report, not fprintf.
2) remove version field from header.
3) header_size is MAX(cluster_size, 4096).
4) introduce s->cluster_sectors.
5) use BLKDBG_L2_LOAD/UPDATE.
v16->v17:
1) Use stringify.
v15->v16:
1) Judge if opts is null in add_cow_create function.
Signed-off-by: Dong Xu Wang <wdon...@linux.vnet.ibm.com>
---
block/Makefile.objs | 1 +
block/add-cow.c | 824 ++++++++++++++++++++++++++++++++++++++++++++++
include/block/block_int.h | 2 +
3 files changed, 827 insertions(+)
create mode 100644 block/add-cow.c
diff --git a/block/Makefile.objs b/block/Makefile.objs
index 69e5584..7f56d71 100644
--- a/block/Makefile.objs
+++ b/block/Makefile.objs
@@ -1,6 +1,7 @@
block-obj-y += raw.o cow.o qcow.o vdi.o vmdk.o cloop.o dmg.o bochs.o vpc.o
vvfat.o
block-obj-y += qcow2.o qcow2-refcount.o qcow2-cluster.o qcow2-snapshot.o
block-obj-y += block-cache.o
+block-obj-y += add-cow.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 += vhdx.o
diff --git a/block/add-cow.c b/block/add-cow.c
new file mode 100644
index 0000000..af766543
--- /dev/null
+++ b/block/add-cow.c
@@ -0,0 +1,824 @@
+/*
+ * QEMU ADD-COW Disk Format
+ *
+ * Copyright IBM, Corp. 2012
+ *
+ * Authors:
+ * Dong Xu Wang <wdon...@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/block_int.h"
+#include "qemu/module.h"
+#include "block/block-cache.h"
+
+#define ACOW_CLUSTER_SIZE 65536
+
+typedef struct AddCowMeta {
+ uint64_t start_sector;
+ int remaining_sectors;
+ CoQueue dependent_requests;
+ struct AddCowMeta *next;
+
+ QLIST_ENTRY(AddCowMeta) next_in_flight;
+} AddCowMeta;
+
+enum {
+ /* compat_features bit */
+ ACOW_F_ALL_ALLOCATED = 0X01,
+
+ /* none feature bit used now */
+ ACOW_FEATURE_MASK = 0,
+
+ ACOW_MAGIC = 'A' | 'C' << 8 | 'O' << 16 | 'W' << 24,
+ ACOW_CACHE_SIZE = 16,
+ DEFAULT_HEADER_SIZE = 4096,
+ MIN_CLUSTER_BITS = 12,
+ MAX_CLUSTER_BITS = 21,
+};
+
+typedef struct AddCowHeader {
+ uint32_t magic;
+
+ uint32_t backing_offset;
+ uint32_t backing_size;
+ uint32_t image_offset;
+ uint32_t image_size;
+
+ uint32_t cluster_bits;
+ uint64_t features;
+ uint64_t compat_features;
+ uint32_t header_size;
+
+ char backing_fmt[16];
+ char image_fmt[16];
+} QEMU_PACKED AddCowHeader;
+
+typedef struct BDRVAddCowState {
+ BlockDriverState *image_hd;
+ CoMutex lock;
+ int cluster_size;
+ int cluster_sectors;
+ BlockCache *bitmap_cache;
+ uint64_t bitmap_size;
+ AddCowHeader header;
+ char backing_fmt[16];
+ char image_fmt[16];
+ BlockCache *image_hd_cache;
+ QLIST_HEAD(AddCowAlloc, AddCowMeta) cluster_allocs;
+} BDRVAddCowState;
+
+/* Convert sector_num to offset in bitmap */
+static inline int64_t offset_in_bitmap(int64_t sector_num,
+ int64_t cluster_sectors)
+{
+ int64_t cluster_num = sector_num / cluster_sectors;
+ return cluster_num / 8;
+}
+
+static inline bool is_cluster_head(int64_t sector_num,
+ int64_t cluster_sectors)
+{
+ return sector_num % cluster_sectors == 0;
+}
+
+static inline bool is_cluster_tail(int64_t sector_num,
+ int64_t cluster_sectors)
+{
+ return (sector_num + 1) % cluster_sectors == 0;
+}
+
+static void add_cow_header_le_to_cpu(const AddCowHeader *le, AddCowHeader *cpu)
+{
+ cpu->magic = le32_to_cpu(le->magic);
+
+ cpu->backing_offset = le32_to_cpu(le->backing_offset);
+ cpu->backing_size = le32_to_cpu(le->backing_size);
+ cpu->image_offset = le32_to_cpu(le->image_offset);
+ cpu->image_size = le32_to_cpu(le->image_size);
+
+ cpu->cluster_bits = le32_to_cpu(le->cluster_bits);
+ cpu->features = le64_to_cpu(le->features);
+ cpu->compat_features = le64_to_cpu(le->compat_features);
+ cpu->header_size = le32_to_cpu(le->header_size);
+
+ memcpy(cpu->backing_fmt, le->backing_fmt, sizeof(cpu->backing_fmt));
+ memcpy(cpu->image_fmt, le->image_fmt, sizeof(cpu->image_fmt));
+}
+
+static void add_cow_header_cpu_to_le(const AddCowHeader *cpu, AddCowHeader *le)
+{
+ le->magic = cpu_to_le32(cpu->magic);
+
+ le->backing_offset = cpu_to_le32(cpu->backing_offset);
+ le->backing_size = cpu_to_le32(cpu->backing_size);
+ le->image_offset = cpu_to_le32(cpu->image_offset);
+ le->image_size = cpu_to_le32(cpu->image_size);
+
+ le->cluster_bits = cpu_to_le32(cpu->cluster_bits);
+ le->features = cpu_to_le64(cpu->features);
+ le->compat_features = cpu_to_le64(cpu->compat_features);
+ le->header_size = cpu_to_le32(cpu->header_size);
+ memcpy(le->backing_fmt, cpu->backing_fmt, sizeof(le->backing_fmt));
+ memcpy(le->image_fmt, cpu->image_fmt, sizeof(le->image_fmt));
+}
+
+static int add_cow_probe(const uint8_t *buf, int buf_size, const char
*filename)
+{
+ const AddCowHeader *header = (const AddCowHeader *)buf;
+
+ if (buf_size < sizeof(*header)) {
+ return 0;
+ }
+ if (le32_to_cpu(header->magic) == ACOW_MAGIC) {
+ return 100;
+ }
+ return 0;
+}
+
+static int add_cow_create(const char *filename, QemuOpts *opts)
+{
+ AddCowHeader header = {
+ .magic = ACOW_MAGIC,
+ .features = 0,
+ .compat_features = 0,
+ };
+ AddCowHeader le_header;
+ int64_t image_len = 0;
+ const char *backing_filename = NULL, *backing_fmt = NULL;
+ const char *image_filename = NULL, *image_format = NULL;
+ size_t cluster_size = ACOW_CLUSTER_SIZE;
+ BlockDriverState *bs, *backing_bs;
+ BlockDriver *drv = bdrv_find_format("add-cow");
+ int ret;
+
+ image_len = qemu_opt_get_size_del(opts, BLOCK_OPT_SIZE, 0);
+ backing_filename = qemu_opt_get_del(opts, BLOCK_OPT_BACKING_FILE);
+ backing_fmt = qemu_opt_get_del(opts, BLOCK_OPT_BACKING_FMT);
+ image_filename = qemu_opt_get_del(opts, BLOCK_OPT_IMAGE_FILE);
+ image_format = qemu_opt_get_del(opts, BLOCK_OPT_IMAGE_FMT);
+ cluster_size = qemu_opt_get_size_del(opts, BLOCK_OPT_CLUSTER_SIZE,
+ ACOW_CLUSTER_SIZE);
+
+ header.cluster_bits = ffs(cluster_size) - 1;
+ if (header.cluster_bits < MIN_CLUSTER_BITS ||
+ header.cluster_bits > MAX_CLUSTER_BITS ||
+ (1 << header.cluster_bits) != cluster_size) {
+ error_report(
+ "Cluster size must be a power of two between %d and %dk",
+ 1 << MIN_CLUSTER_BITS, 1 << (MAX_CLUSTER_BITS - 10));
+ return -EINVAL;
+ }
+
+ header.header_size = MAX(cluster_size, DEFAULT_HEADER_SIZE);
+ if (backing_filename) {
+ header.backing_offset = sizeof(header);
+ header.backing_size = strlen(backing_filename);
+
+ if (!backing_fmt) {
+ backing_bs = bdrv_new("image");
+ ret = bdrv_open(backing_bs, backing_filename, NULL,
+ BDRV_O_RDWR | BDRV_O_CACHE_WB, NULL);
+ if (ret < 0) {
+ bdrv_delete(backing_bs);
+ return ret;
+ }
+ backing_fmt = bdrv_get_format_name(backing_bs);
+ bdrv_delete(backing_bs);
+ }
+ } else {
+ header.compat_features |= ACOW_F_ALL_ALLOCATED;
+ }
+
+ if (image_filename) {
+ header.image_offset = sizeof(header) + header.backing_size;
+ header.image_size = strlen(image_filename);
+ } else {
+ error_report("Error: 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_offset + header.image_size > header.header_size) {
+ error_report("image_file name or backing_file name too long.");
+ return -ENOSPC;
+ }
+
+ ret = bdrv_file_open(&bs, image_filename, NULL, 0);
+ if (ret < 0) {
+ return ret;
+ }
+ bdrv_close(bs);
+
+ ret = bdrv_create_file(filename, NULL);
+ if (ret < 0) {
+ return ret;
+ }
+
+ ret = bdrv_file_open(&bs, filename, NULL, BDRV_O_RDWR);
+ if (ret < 0) {
+ return ret;
+ }
+ assert(strlen(backing_fmt ? backing_fmt : "") <
sizeof(header.backing_fmt));
+ strncpy(header.backing_fmt, backing_fmt ? backing_fmt : "",
+ sizeof(header.backing_fmt));
+ assert(strlen(image_format ? image_format : "raw")
+ < sizeof(header.image_fmt));
+ strncpy(header.image_fmt, image_format ? image_format : "raw",
+ sizeof(header.image_fmt));
+ 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, header.image_offset, image_filename,
+ header.image_size);
+ if (ret < 0) {
+ bdrv_delete(bs);
+ return ret;
+ }
+
+ if (backing_filename) {
+ ret = bdrv_pwrite(bs, header.backing_offset, backing_filename,
+ header.backing_size);
+ if (ret < 0) {
+ bdrv_delete(bs);
+ return ret;
+ }
+ }
+ bdrv_close(bs);
+
+ ret = bdrv_open(bs, filename, NULL, 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, QDict *options, int flags)
+{
+ char image_filename[PATH_MAX];
+ char tmp_name[PATH_MAX];
+ int ret;
+ int sector_per_byte;
+ BDRVAddCowState *s = bs->opaque;
+ AddCowHeader le_header;
+ char backing_filename[PATH_MAX];
+
+ ret = bdrv_pread(bs->file, 0, &le_header, sizeof(le_header));
+ if (ret < 0) {
+ goto fail;
+ }
+
+ add_cow_header_le_to_cpu(&le_header, &s->header);
+
+ if (s->header.magic != ACOW_MAGIC) {
+ ret = -EINVAL;
+ goto fail;
+ }
+
+ if (s->header.features & ~ACOW_FEATURE_MASK) {
+ char buf[64];
+ snprintf(buf, sizeof(buf), "Feature Flags: %" PRIx64,
+ s->header.features & ~ACOW_FEATURE_MASK);
+ qerror_report(QERR_UNKNOWN_BLOCK_FORMAT_FEATURE,
+ bs->device_name, "add-cow", buf);
+ return -ENOTSUP;
+ }
+
+ if ((s->header.compat_features & ACOW_F_ALL_ALLOCATED) == 0) {
+ snprintf(bs->backing_format, sizeof(bs->backing_format),
+ "%s", s->header.backing_fmt);
+ }
+
+ if (s->header.cluster_bits < MIN_CLUSTER_BITS ||
+ s->header.cluster_bits > MAX_CLUSTER_BITS) {
+ ret = -EINVAL;
+ goto fail;
+ }
+
+ s->cluster_size = 1 << s->header.cluster_bits;
+ if (s->header.header_size != MAX(s->cluster_size, DEFAULT_HEADER_SIZE)) {
+ char buf[64];
+ snprintf(buf, sizeof(buf), "Header size: %u",
+ s->header.header_size);
+ qerror_report(QERR_UNKNOWN_BLOCK_FORMAT_FEATURE,
+ bs->device_name, "add-cow", buf);
+ return -ENOTSUP;
+ }
+
+ if ((s->header.compat_features & ACOW_F_ALL_ALLOCATED) == 0) {
+ ret = bdrv_read_string(bs->file, s->header.backing_offset,
+ s->header.backing_size,
+ bs->backing_file,
+ sizeof(bs->backing_file));
+ if (ret < 0) {
+ goto fail;
+ }
+ }
+
+ ret = bdrv_read_string(bs->file, s->header.image_offset,
+ s->header.image_size, tmp_name,
+ sizeof(tmp_name));
+ if (ret < 0) {
+ goto fail;
+ }
+
+ if (path_has_protocol(tmp_name)) {
+ pstrcpy(image_filename, sizeof(image_filename), tmp_name);
+ } else {
+ path_combine(image_filename, sizeof(image_filename),
+ bs->filename, tmp_name);
+ }
+ bdrv_get_full_backing_filename(bs, backing_filename,
+ sizeof(backing_filename));
+ if (!strcmp(backing_filename, image_filename)) {
+ error_report("Error: backing file and image file are same: %s\n",
+ backing_filename);
+ ret = EINVAL;
+ goto fail;
+ }
+ s->image_hd = bdrv_new("");
+ ret = bdrv_open(s->image_hd, image_filename, NULL, flags,
+ bdrv_find_format(s->header.image_fmt));
+ if (ret < 0) {
+ bdrv_delete(s->image_hd);
+ goto fail;
+ }
+
+ bs->total_sectors = bdrv_getlength(s->image_hd) / BDRV_SECTOR_SIZE;
+ s->cluster_sectors = s->cluster_size / BDRV_SECTOR_SIZE;
+ sector_per_byte = s->cluster_sectors * 8;
+ s->bitmap_size =
+ (bs->total_sectors + sector_per_byte - 1) / sector_per_byte;
+ s->bitmap_cache = block_cache_create(bs, ACOW_CACHE_SIZE,
+ s->cluster_size,
+ BLOCK_TABLE_BITMAP);
+ s->image_hd_cache = block_cache_create(s->image_hd, 0, 0, 0);
+ block_cache_depends_on_flush(s->image_hd_cache);
+ qemu_co_mutex_init(&s->lock);
+ QLIST_INIT(&s->cluster_allocs);
+ return 0;
+fail:
+ return ret;
+}
+
+static void add_cow_close(BlockDriverState *bs)
+{
+ BDRVAddCowState *s = bs->opaque;
+ if (s->bitmap_cache) {
+ block_cache_destroy(bs, s->bitmap_cache);
+ }
+ if (s->image_hd_cache) {
+ block_cache_destroy(s->image_hd, s->image_hd_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 / s->cluster_sectors;
+ uint8_t *table = NULL;
+ bool val = false;
+ int ret;
+
+ uint64_t offset = s->header.header_size +
+ (offset_in_bitmap(sector_num, s->cluster_sectors)
+ & (~(s->cluster_size - 1)));
+ ret = block_cache_get(bs, s->bitmap_cache, offset, (void **)&table);
+ if (ret < 0) {
+ return ret;
+ }
+
+ val = table[cluster_num / 8 % s->cluster_size] & (1 << (cluster_num % 8));
+ ret = block_cache_put(bs, s->bitmap_cache, (void **)&table);
+ if (ret < 0) {
+ return ret;
+ }
+ return val;
+}
+
+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.compat_features & ACOW_F_ALL_ALLOCATED) {
+ *num_same = nb_sectors;
+ 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 int add_cow_backing_read(BlockDriverState *bs, QEMUIOVector *qiov,
+ int64_t sector_num, int nb_sectors)
+{
+ int n1;
+ if ((sector_num + nb_sectors) <= bs->total_sectors) {
+ return nb_sectors;
+ }
+ if (sector_num >= bs->total_sectors) {
+ n1 = 0;
+ } else {
+ n1 = bs->total_sectors - sector_num;
+ }
+
+ qemu_iovec_memset(qiov, BDRV_SECTOR_SIZE * n1,
+ 0, BDRV_SECTOR_SIZE * (nb_sectors - n1));
+
+ return n1;
+}
+
+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 n1, 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,
+ &cur_nr_sectors)) {
+ 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,
+ cur_nr_sectors, &hd_qiov);
+ qemu_co_mutex_lock(&s->lock);
+ if (ret < 0) {
+ goto fail;
+ }
+ } else {
+ if (bs->backing_hd) {
+ qemu_iovec_reset(&hd_qiov);
+ qemu_iovec_concat(&hd_qiov, qiov, bytes_done,
+ cur_nr_sectors * BDRV_SECTOR_SIZE);
+ n1 = add_cow_backing_read(bs->backing_hd, &hd_qiov,
+ sector_num, cur_nr_sectors);
+ if (n1 > 0) {
+ qemu_co_mutex_unlock(&s->lock);
+ ret = bdrv_co_readv(bs->backing_hd, sector_num,
+ cur_nr_sectors, &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 int handle_dependencies(BlockDriverState *bs, uint64_t sector_num,
+ int remaining_sectors)
+{
+ BDRVAddCowState *s = bs->opaque;
+ AddCowMeta *old_alloc;
+ QLIST_FOREACH(old_alloc, &s->cluster_allocs, next_in_flight) {
+ uint64_t start = sector_num;
+ uint64_t end = sector_num + remaining_sectors;
+ uint64_t old_start = old_alloc->start_sector;
+ uint64_t old_end =
+ old_alloc->start_sector + old_alloc->remaining_sectors;
+ if (end <= old_start || start >= old_end) {
+ /* No intersection */
+ } else {
+ qemu_co_mutex_unlock(&s->lock);
+ qemu_co_queue_wait(&old_alloc->dependent_requests);
+ qemu_co_mutex_lock(&s->lock);
+ return -EAGAIN;
+ }
+ }
+ return 0;
+}
+
+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;
+ uint64_t offset;
+ int mask = s->cluster_sectors - 1;
+ int cluster_mask = s->cluster_size - 1;
+ AddCowMeta *meta = NULL;
+
+ if (remaining_sectors == 0) {
+ return ret;
+ }
+ qemu_iovec_init(&hd_qiov, qiov->niov);
+
+ qemu_co_mutex_lock(&s->lock);
+
+ meta = g_malloc0(sizeof(*meta));
+again:
+ *meta = (AddCowMeta) {
+ .next = QLIST_FIRST(&s->cluster_allocs),
+ .start_sector = sector_num,
+ .remaining_sectors = remaining_sectors,
+ };
+ if (handle_dependencies(bs, sector_num, remaining_sectors) == -EAGAIN) {
+ goto again;
+ }
+ qemu_co_queue_init(&meta->dependent_requests);
+ QLIST_INSERT_HEAD(&s->cluster_allocs, meta, next_in_flight);
+ ret = bdrv_co_writev(s->image_hd, sector_num, remaining_sectors, qiov);
+
+ if (ret == 0 && !s->image_hd->enable_write_cache) {
+ ret = bdrv_co_flush(s->image_hd);
+ }
+ if (ret < 0) {
+ goto fail;
+ }
+ if ((s->header.compat_features & ACOW_F_ALL_ALLOCATED) == 0) {
+ /* Copy content of unmodified sectors */
+ if (!is_cluster_head(sector_num, s->cluster_sectors)
+ && !is_allocated(bs, sector_num)) {
+ ret = copy_sectors(bs, sector_num & ~mask, sector_num);
+ if (ret < 0) {
+ goto fail;
+ }
+ }
+
+ if (!is_cluster_tail(sector_num + remaining_sectors - 1,
+ s->cluster_sectors)
+ && !is_allocated(bs, sector_num + remaining_sectors - 1)) {
+ ret = copy_sectors(bs, sector_num + remaining_sectors,
+ ((sector_num + remaining_sectors) | mask) + 1);
+ if (ret < 0) {
+ goto fail;
+ }
+ }
+
+ for (i = sector_num / s->cluster_sectors;
+ i <= (sector_num + remaining_sectors - 1) / s->cluster_sectors;
+ i++) {
+ offset = s->header.header_size
+ + (offset_in_bitmap(i * s->cluster_sectors,
+ s->cluster_sectors) & (~cluster_mask));
+ ret = block_cache_get(bs, s->bitmap_cache, offset, (void
**)&table);
+ if (ret < 0) {
+ goto fail;
+ }
+
+ block_cache_set_dependency_two_bs(bs, s->bitmap_cache,
+ s->image_hd, s->image_hd_cache);
+ if (!(table[(i / 8) & (s->cluster_size - 1)] & (1 << (i % 8)))) {
+ table[(i / 8) & (s->cluster_size - 1)] |= (1 << (i % 8));
+ block_cache_entry_mark_dirty(s->bitmap_cache, table);
+ }
+
+ ret = block_cache_put(bs, s->bitmap_cache, (void **) &table);
+ if (ret < 0) {
+ goto fail;
+ }
+ }
+ }
+ ret = 0;
+fail:
+ while (meta != NULL) {
+ AddCowMeta *next;
+
+ if (meta->remaining_sectors != 0) {
+ QLIST_REMOVE(meta, next_in_flight);
+ }
+ qemu_co_queue_restart_all(&meta->dependent_requests);
+
+ next = meta->next;
+ g_free(meta);
+ meta = next;
+ }
+
+ 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 = s->cluster_sectors * 8;
+ int ret;
+ int64_t bitmap_size =
+ (size / BDRV_SECTOR_SIZE + sector_per_byte - 1) / sector_per_byte;
+ bitmap_size = (bitmap_size + s->cluster_size - 1)
+ & (~(s->cluster_size - 1));
+
+ ret = bdrv_truncate(bs->file, s->header.header_size + bitmap_size);
+ if (ret < 0) {
+ return ret;
+ }
+
+ ret = bdrv_truncate(s->image_hd, size);
+ if (ret < 0) {
+ return ret;
+ }
+ return 0;
+}
+
+static int add_cow_reopen_prepare(BDRVReopenState *state,
+ BlockReopenQueue *queue, Error **errp)
+{
+ BDRVAddCowState *s;
+ int ret = -1;
+
+ assert(state != NULL);
+ assert(state->bs != NULL);
+
+ if (queue == NULL) {
+ error_set(errp, ERROR_CLASS_GENERIC_ERROR,
+ "No reopen queue for add-cow");
+ goto exit;
+ }
+
+ s = state->bs->opaque;
+
+ assert(s != NULL);
+
+
+ bdrv_reopen_queue(queue, s->image_hd, state->flags);
+ ret = 0;
+
+exit:
+ return ret;
+}
+
+
+static coroutine_fn int add_cow_co_flush(BlockDriverState *bs)
+{
+ BDRVAddCowState *s = bs->opaque;
+ int ret = 0;
+
+ qemu_co_mutex_lock(&s->lock);
+ if (s->image_hd_cache) {
+ ret = block_cache_flush(s->image_hd, s->image_hd_cache);
+ if (ret < 0) {
+ qemu_co_mutex_unlock(&s->lock);
+ return ret;
+ }
+ }
+ if (s->bitmap_cache) {
+ ret = block_cache_flush(bs, s->bitmap_cache);
+ }
+ qemu_co_mutex_unlock(&s->lock);
+ return ret;
+}
+
+static int add_cow_get_info(BlockDriverState *bs, BlockDriverInfo *bdi)
+{
+ BDRVAddCowState *s = bs->opaque;
+ bdi->cluster_size = s->cluster_size;
+ return 0;
+}
+
+static QemuOptsList add_cow_create_opts = {
+ .name = "add-cow-create-opts",
+ .head = QTAILQ_HEAD_INITIALIZER(add_cow_create_opts.head),
+ .desc = {
+ {
+ .name = BLOCK_OPT_SIZE,
+ .type = QEMU_OPT_SIZE,
+ .help = "Virtual disk size"
+ },
+ {
+ .name = BLOCK_OPT_BACKING_FILE,
+ .type = QEMU_OPT_STRING,
+ .help = "File name of a base image"
+ },
+ {
+ .name = BLOCK_OPT_BACKING_FMT,
+ .type = QEMU_OPT_STRING,
+ .help = "Image format of the base image"
+ },
+ {
+ .name = BLOCK_OPT_IMAGE_FILE,
+ .type = QEMU_OPT_STRING,
+ .help = "File name of a image file"
+ },
+ {
+ .name = BLOCK_OPT_IMAGE_FMT,
+ .type = QEMU_OPT_STRING,
+ .help = "Image format of the image file"
+ },
+ {
+ .name = BLOCK_OPT_CLUSTER_SIZE,
+ .type = QEMU_OPT_SIZE,
+ .help = "add-cow cluster size",
+ .def_value_str = stringify(ACOW_CLUSTER_SIZE)
+ },
+ { /* end of list */ }
+ }
+};
+
+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,
+ .bdrv_reopen_prepare = add_cow_reopen_prepare,
+ .bdrv_get_info = add_cow_get_info,
+
+ .bdrv_create_opts = &add_cow_create_opts,
+ .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/include/block/block_int.h b/include/block/block_int.h
index 09bf260..3cbfa84 100644
--- a/include/block/block_int.h
+++ b/include/block/block_int.h
@@ -58,6 +58,8 @@
#define BLOCK_OPT_COMPAT_LEVEL "compat"
#define BLOCK_OPT_LAZY_REFCOUNTS "lazy_refcounts"
#define BLOCK_OPT_ADAPTER_TYPE "adapter_type"
+#define BLOCK_OPT_IMAGE_FILE "image_file"
+#define BLOCK_OPT_IMAGE_FMT "image_fmt"
typedef struct BdrvTrackedRequest {
BlockDriverState *bs;
--
1.7.11.7
