| Message ID | 1344613185-12308-6-git-send-email-wdongxu@linux.vnet.ibm.com |
|---|---|
| State | New |
| Headers | show |
On Fri, Aug 10, 2012 at 11:39:44PM +0800, Dong Xu Wang wrote: > add-cow file format core code. It use block-cache.c as cache code. > > Signed-off-by: Dong Xu Wang <wdongxu@linux.vnet.ibm.com> > --- > block/Makefile.objs | 1 + > block/add-cow.c | 613 +++++++++++++++++++++++++++++++++++++++++++++++++++ > block/add-cow.h | 85 +++++++ > block_int.h | 2 + > 4 files changed, 701 insertions(+), 0 deletions(-) > 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 23bdfc8..7ed5051 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 > 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 > block-obj-y += block-cache.o > block-obj-y += parallels.o nbd.o blkdebug.o sheepdog.o blkverify.o > block-obj-y += stream.o > diff --git a/block/add-cow.c b/block/add-cow.c > new file mode 100644 > index 0000000..d4711d5 > --- /dev/null > +++ b/block/add-cow.c > @@ -0,0 +1,613 @@ > +/* > + * 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 image_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"); > + BDRVAddCowState s; > + int ret; > + > + 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; > + } else if (!strcmp(options->name, BLOCK_OPT_IMAGE_FORMAT)) { > + image_format = options->value.s; > + } > + options++; > + } > + > + if (backing_filename) { > + header.backing_filename_offset = sizeof(header) > + + sizeof(s.backing_file_format) + sizeof(s.image_file_format); > + 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.image_filename_offset = > + sizeof(header) + sizeof(s.backing_file_format) > + + sizeof(s.image_file_format) + header.backing_filename_size; > + header.image_filename_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_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 ? strlen(backing_fmt) : 0); > + if (ret < 0) { > + bdrv_delete(bs); > + return ret; > + } > + > + ret = bdrv_pwrite(bs, sizeof(le_header) + sizeof(s.backing_file_format), > + image_format ? image_format : "raw", > + image_format ? strlen(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, 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; > + 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_All_ALLOCATED) == 0) { > + ret = bdrv_read_string(bs->file, sizeof(s->header), > + sizeof(s->backing_file_format) - 1, s->backing_file_format, > + sizeof(s->backing_file_format)); > + if (ret < 0) { > + goto fail; > + } > + } > + > + ret = bdrv_read_string(bs->file, > + sizeof(s->header) + sizeof(s->image_file_format), > + sizeof(s->image_file_format) - 1, 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; > + } > + > + 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; > + s->bitmap_cache = > + block_cache_create(bs, ADD_COW_CACHE_SIZE, ADD_COW_CACHE_ENTRY_SIZE); > + > + qemu_co_mutex_init(&s->lock); > + return 0; > +fail: > + if (s->bitmap_cache) { > + block_cache_destroy(bs, s->bitmap_cache, BLOCK_TABLE_BITMAP); > + } > + return ret; > +} > + > +static void add_cow_close(BlockDriverState *bs) > +{ > + BDRVAddCowState *s = bs->opaque; > + block_cache_destroy(bs, s->bitmap_cache, BLOCK_TABLE_BITMAP); > + bdrv_delete(s->image_hd); > +} > + > +static bool is_allocated(BlockDriverState *bs, int64_t sector_num) > +{ > + BDRVAddCowState *s = bs->opaque; > + BlockCache *c = s->bitmap_cache; > + int64_t cluster_num = sector_num / SECTORS_PER_CLUSTER; > + uint8_t *table = NULL; > + uint64_t offset = ADD_COW_PAGE_SIZE * s->header.header_pages_size > + + (offset_in_bitmap(sector_num) & (~(c->entry_size - 1))); > + int ret = block_cache_get(bs, s->bitmap_cache, offset, > + (void **)&table, BLOCK_TABLE_BITMAP, ADD_COW_CACHE_ENTRY_SIZE); > + > + 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 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 n, 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, &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); > + 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, > + 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; > + BlockCache *c = s->bitmap_cache; > + int ret = 0, i; > + QEMUIOVector hd_qiov; > + uint8_t *table; > + uint64_t offset; > + > + 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); alignment ^ or even at ^ if you prefer and have done in some places, just need to be consistent about it for better readability. > + > + 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)) { Why do we avoid a COW when writing to the first sector of a cluster? > + 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++) { > + offset = ADD_COW_PAGE_SIZE * s->header.header_pages_size > + + (offset_in_bitmap(i * SECTORS_PER_CLUSTER) & (~(c->entry_size - 1))); > + ret = block_cache_get(bs, s->bitmap_cache, offset, > + (void **)&table, BLOCK_TABLE_BITMAP, ADD_COW_CACHE_ENTRY_SIZE); > + if (ret < 0) { > + goto fail; > + } > + if ((table[i / 8] & (1 << (i % 8))) == 0) { > + table[i / 8] |= (1 << (i % 8)); > + block_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; > + bitmap_size = (bitmap_size + ADD_COW_CACHE_ENTRY_SIZE - 1) > + & (~(ADD_COW_CACHE_ENTRY_SIZE - 1)); > + > + 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 = block_cache_flush(bs, s->bitmap_cache, BLOCK_TABLE_BITMAP, > + ADD_COW_CACHE_ENTRY_SIZE); > + 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..f058376 > --- /dev/null > +++ b/block/add-cow.h > @@ -0,0 +1,85 @@ > +/* > + * 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 > +#include "block-cache.h" > + > +enum { > + ADD_COW_F_All_ALLOCATED = 0X01, Please use "ADD_COW_F_ALL_ALLOCATED" (all caps) was searching your patch for how this was used and was scratching my head when I wasn't seeing any matches :) > + ADD_COW_FEATURE_MASK = 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; You should avoid using packed structures for image format headers. Instead, I would either: a) re-order the fields so that 32/64-bit fields, respectively, fall on 32/64-bit boundaries (in your case, for instance, moving header_pages_size above features) like qed/qcow2 do, or b) read/write the fields individually rather than reading/writing directly into/from the header struct. The safest route is b). Adds a few lines of code, but you won't have to re-work things (or worry about introducing bugs) later if you were to add, say, a 32-bit value, and then a 64-bit value later. > + > +typedef struct BDRVAddCowState { > + BlockDriverState *image_hd; > + CoMutex lock; > + int cluster_size; > + BlockCache *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; > +} > + > +BlockCache *add_cow_cache_create(BlockDriverState *bs, int num_tables); > +int add_cow_cache_destroy(BlockDriverState *bs, BlockCache *c); > +void add_cow_cache_entry_mark_dirty(BlockCache *c, void *table); > +int add_cow_cache_get(BlockDriverState *bs, BlockCache *c, uint64_t offset, > + void **table); > +int add_cow_cache_flush(BlockDriverState *bs, BlockCache *c); > +#endif > diff --git a/block_int.h b/block_int.h > index 6c1d9ca..67954ec 100644 > --- a/block_int.h > +++ b/block_int.h > @@ -53,6 +53,8 @@ > #define BLOCK_OPT_SUBFMT "subformat" > #define BLOCK_OPT_COMPAT_LEVEL "compat" > #define BLOCK_OPT_LAZY_REFCOUNTS "lazy_refcounts" > +#define BLOCK_OPT_IMAGE_FILE "image_file" > +#define BLOCK_OPT_IMAGE_FORMAT "image_format" > > typedef struct BdrvTrackedRequest BdrvTrackedRequest; > > -- > 1.7.1 > >
On Fri, Sep 7, 2012 at 4:19 AM, Michael Roth <mdroth@linux.vnet.ibm.com> wrote: > On Fri, Aug 10, 2012 at 11:39:44PM +0800, Dong Xu Wang wrote: >> add-cow file format core code. It use block-cache.c as cache code. >> >> Signed-off-by: Dong Xu Wang <wdongxu@linux.vnet.ibm.com> >> --- >> block/Makefile.objs | 1 + >> block/add-cow.c | 613 +++++++++++++++++++++++++++++++++++++++++++++++++++ >> block/add-cow.h | 85 +++++++ >> block_int.h | 2 + >> 4 files changed, 701 insertions(+), 0 deletions(-) >> 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 23bdfc8..7ed5051 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 >> 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 >> block-obj-y += block-cache.o >> block-obj-y += parallels.o nbd.o blkdebug.o sheepdog.o blkverify.o >> block-obj-y += stream.o >> diff --git a/block/add-cow.c b/block/add-cow.c >> new file mode 100644 >> index 0000000..d4711d5 >> --- /dev/null >> +++ b/block/add-cow.c >> @@ -0,0 +1,613 @@ >> +/* >> + * 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 image_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"); >> + BDRVAddCowState s; >> + int ret; >> + >> + 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; >> + } else if (!strcmp(options->name, BLOCK_OPT_IMAGE_FORMAT)) { >> + image_format = options->value.s; >> + } >> + options++; >> + } >> + >> + if (backing_filename) { >> + header.backing_filename_offset = sizeof(header) >> + + sizeof(s.backing_file_format) + sizeof(s.image_file_format); >> + 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.image_filename_offset = >> + sizeof(header) + sizeof(s.backing_file_format) >> + + sizeof(s.image_file_format) + header.backing_filename_size; >> + header.image_filename_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_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 ? strlen(backing_fmt) : 0); >> + if (ret < 0) { >> + bdrv_delete(bs); >> + return ret; >> + } >> + >> + ret = bdrv_pwrite(bs, sizeof(le_header) + sizeof(s.backing_file_format), >> + image_format ? image_format : "raw", >> + image_format ? strlen(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, 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; >> + 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_All_ALLOCATED) == 0) { >> + ret = bdrv_read_string(bs->file, sizeof(s->header), >> + sizeof(s->backing_file_format) - 1, s->backing_file_format, >> + sizeof(s->backing_file_format)); >> + if (ret < 0) { >> + goto fail; >> + } >> + } >> + >> + ret = bdrv_read_string(bs->file, >> + sizeof(s->header) + sizeof(s->image_file_format), >> + sizeof(s->image_file_format) - 1, 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; >> + } >> + >> + 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; >> + s->bitmap_cache = >> + block_cache_create(bs, ADD_COW_CACHE_SIZE, ADD_COW_CACHE_ENTRY_SIZE); >> + >> + qemu_co_mutex_init(&s->lock); >> + return 0; >> +fail: >> + if (s->bitmap_cache) { >> + block_cache_destroy(bs, s->bitmap_cache, BLOCK_TABLE_BITMAP); >> + } >> + return ret; >> +} >> + >> +static void add_cow_close(BlockDriverState *bs) >> +{ >> + BDRVAddCowState *s = bs->opaque; >> + block_cache_destroy(bs, s->bitmap_cache, BLOCK_TABLE_BITMAP); >> + bdrv_delete(s->image_hd); >> +} >> + >> +static bool is_allocated(BlockDriverState *bs, int64_t sector_num) >> +{ >> + BDRVAddCowState *s = bs->opaque; >> + BlockCache *c = s->bitmap_cache; >> + int64_t cluster_num = sector_num / SECTORS_PER_CLUSTER; >> + uint8_t *table = NULL; >> + uint64_t offset = ADD_COW_PAGE_SIZE * s->header.header_pages_size >> + + (offset_in_bitmap(sector_num) & (~(c->entry_size - 1))); >> + int ret = block_cache_get(bs, s->bitmap_cache, offset, >> + (void **)&table, BLOCK_TABLE_BITMAP, ADD_COW_CACHE_ENTRY_SIZE); >> + >> + 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 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 n, 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, &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); >> + 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, >> + 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; >> + BlockCache *c = s->bitmap_cache; >> + int ret = 0, i; >> + QEMUIOVector hd_qiov; >> + uint8_t *table; >> + uint64_t offset; >> + >> + 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); > > alignment ^ > > or even at ^ if you prefer and have done in some places, just need to be > consistent about it for better readability. > >> + >> + 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)) { > > Why do we avoid a COW when writing to the first sector of a cluster? Because if it is the first sector, we need not use copy_sector, we write it directly would be enough, it starts at the begening of one cluster. > >> + 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++) { >> + offset = ADD_COW_PAGE_SIZE * s->header.header_pages_size >> + + (offset_in_bitmap(i * SECTORS_PER_CLUSTER) & (~(c->entry_size - 1))); >> + ret = block_cache_get(bs, s->bitmap_cache, offset, >> + (void **)&table, BLOCK_TABLE_BITMAP, ADD_COW_CACHE_ENTRY_SIZE); >> + if (ret < 0) { >> + goto fail; >> + } >> + if ((table[i / 8] & (1 << (i % 8))) == 0) { >> + table[i / 8] |= (1 << (i % 8)); >> + block_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; >> + bitmap_size = (bitmap_size + ADD_COW_CACHE_ENTRY_SIZE - 1) >> + & (~(ADD_COW_CACHE_ENTRY_SIZE - 1)); >> + >> + 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 = block_cache_flush(bs, s->bitmap_cache, BLOCK_TABLE_BITMAP, >> + ADD_COW_CACHE_ENTRY_SIZE); >> + 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..f058376 >> --- /dev/null >> +++ b/block/add-cow.h >> @@ -0,0 +1,85 @@ >> +/* >> + * 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 >> +#include "block-cache.h" >> + >> +enum { >> + ADD_COW_F_All_ALLOCATED = 0X01, > > Please use "ADD_COW_F_ALL_ALLOCATED" (all caps) Okay. > > was searching your patch for how this was used and was scratching my > head when I wasn't seeing any matches :) It wil be used such as: qemu-img create -f add-cow -o image_file=t.raw t.add-cow while we need not read from backing_file any more. > >> + ADD_COW_FEATURE_MASK = 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; > > You should avoid using packed structures for image format headers. > Instead, I would either: > > a) re-order the fields so that 32/64-bit fields, respectively, fall on > 32/64-bit boundaries (in your case, for instance, moving header_pages_size > above features) like qed/qcow2 do, or > > b) read/write the fields individually rather than reading/writing directly > into/from the header struct. > > The safest route is b). Adds a few lines of code, but you won't have to > re-work things (or worry about introducing bugs) later if you were to add, > say, a 32-bit value, and then a 64-bit value later. While, Kevin's suggestion is using PACKED, so .. > >> + >> +typedef struct BDRVAddCowState { >> + BlockDriverState *image_hd; >> + CoMutex lock; >> + int cluster_size; >> + BlockCache *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; >> +} >> + >> +BlockCache *add_cow_cache_create(BlockDriverState *bs, int num_tables); >> +int add_cow_cache_destroy(BlockDriverState *bs, BlockCache *c); >> +void add_cow_cache_entry_mark_dirty(BlockCache *c, void *table); >> +int add_cow_cache_get(BlockDriverState *bs, BlockCache *c, uint64_t offset, >> + void **table); >> +int add_cow_cache_flush(BlockDriverState *bs, BlockCache *c); >> +#endif >> diff --git a/block_int.h b/block_int.h >> index 6c1d9ca..67954ec 100644 >> --- a/block_int.h >> +++ b/block_int.h >> @@ -53,6 +53,8 @@ >> #define BLOCK_OPT_SUBFMT "subformat" >> #define BLOCK_OPT_COMPAT_LEVEL "compat" >> #define BLOCK_OPT_LAZY_REFCOUNTS "lazy_refcounts" >> +#define BLOCK_OPT_IMAGE_FILE "image_file" >> +#define BLOCK_OPT_IMAGE_FORMAT "image_format" >> >> typedef struct BdrvTrackedRequest BdrvTrackedRequest; >> >> -- >> 1.7.1 >> >> >
Am 10.08.2012 17:39, schrieb Dong Xu Wang: > add-cow file format core code. It use block-cache.c as cache code. > > Signed-off-by: Dong Xu Wang <wdongxu@linux.vnet.ibm.com> > --- > block/Makefile.objs | 1 + > block/add-cow.c | 613 +++++++++++++++++++++++++++++++++++++++++++++++++++ > block/add-cow.h | 85 +++++++ > block_int.h | 2 + > 4 files changed, 701 insertions(+), 0 deletions(-) > 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 23bdfc8..7ed5051 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 > 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 > block-obj-y += block-cache.o > block-obj-y += parallels.o nbd.o blkdebug.o sheepdog.o blkverify.o > block-obj-y += stream.o > diff --git a/block/add-cow.c b/block/add-cow.c > new file mode 100644 > index 0000000..d4711d5 > --- /dev/null > +++ b/block/add-cow.c > @@ -0,0 +1,613 @@ > +/* > + * 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 image_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"); > + BDRVAddCowState s; > + int ret; > + > + 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; > + } else if (!strcmp(options->name, BLOCK_OPT_IMAGE_FORMAT)) { > + image_format = options->value.s; > + } > + options++; > + } > + > + if (backing_filename) { > + header.backing_filename_offset = sizeof(header) > + + sizeof(s.backing_file_format) + sizeof(s.image_file_format); > + 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.image_filename_offset = > + sizeof(header) + sizeof(s.backing_file_format) > + + sizeof(s.image_file_format) + header.backing_filename_size; > + header.image_filename_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_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 ? strlen(backing_fmt) : 0); The spec requires zero padding, which you don't do here. > + if (ret < 0) { > + bdrv_delete(bs); > + return ret; > + } > + > + ret = bdrv_pwrite(bs, sizeof(le_header) + sizeof(s.backing_file_format), > + image_format ? image_format : "raw", > + image_format ? strlen(image_format) : sizeof("raw")); And here. > + 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, 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; > + 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)) { if (ret < 0) would be more consistent with the rest of the code. > + goto fail; > + } > + > + add_cow_header_le_to_cpu(&le_header, &s->header); > + > + if (le64_to_cpu(s->header.magic) != ADD_COW_MAGIC) { Isn't this one endianess conversion too much? s->header is already LE. Did you test add-cow on a big endian host? > + 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); This message is a bit terse, most users will be confused with an error message that only consists of a hex number. Maybe better "Feature flags: %" PRIx64. > + qerror_report(QERR_UNKNOWN_BLOCK_FORMAT_FEATURE, > + bs->device_name, "add-cow", buf); > + return -ENOTSUP; > + } > + > + if ((s->header.features & ADD_COW_F_All_ALLOCATED) == 0) { > + ret = bdrv_read_string(bs->file, sizeof(s->header), > + sizeof(s->backing_file_format) - 1, s->backing_file_format, > + sizeof(s->backing_file_format)); > + if (ret < 0) { > + goto fail; > + } > + } Would be great if this was not only read into memory, but actually used... It must end up in bs->backing_format in order take effect. > + > + ret = bdrv_read_string(bs->file, > + sizeof(s->header) + sizeof(s->image_file_format), > + sizeof(s->image_file_format) - 1, s->image_file_format, > + sizeof(s->image_file_format)); > + if (ret < 0) { > + goto fail; > + } This one is unused, too. > + > + 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); image_drv is always NULL. > + 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; > + s->bitmap_cache = > + block_cache_create(bs, ADD_COW_CACHE_SIZE, ADD_COW_CACHE_ENTRY_SIZE); > + > + qemu_co_mutex_init(&s->lock); > + return 0; > +fail: > + if (s->bitmap_cache) { > + block_cache_destroy(bs, s->bitmap_cache, BLOCK_TABLE_BITMAP); > + } > + return ret; > +} > + > +static void add_cow_close(BlockDriverState *bs) > +{ > + BDRVAddCowState *s = bs->opaque; > + block_cache_destroy(bs, s->bitmap_cache, BLOCK_TABLE_BITMAP); > + bdrv_delete(s->image_hd); > +} > + > +static bool is_allocated(BlockDriverState *bs, int64_t sector_num) > +{ > + BDRVAddCowState *s = bs->opaque; > + BlockCache *c = s->bitmap_cache; > + int64_t cluster_num = sector_num / SECTORS_PER_CLUSTER; > + uint8_t *table = NULL; > + uint64_t offset = ADD_COW_PAGE_SIZE * s->header.header_pages_size > + + (offset_in_bitmap(sector_num) & (~(c->entry_size - 1))); > + int ret = block_cache_get(bs, s->bitmap_cache, offset, > + (void **)&table, BLOCK_TABLE_BITMAP, ADD_COW_CACHE_ENTRY_SIZE); No matching block_cache_put? > + > + 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; Why - 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 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 n, 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, &n)) { > + cur_nr_sectors = n; One of n and cur_nr_sectors is redundant. > + 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); > + 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, > + 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; > + BlockCache *c = s->bitmap_cache; > + int ret = 0, i; > + QEMUIOVector hd_qiov; > + uint8_t *table; > + uint64_t offset; > + > + 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++) { > + offset = ADD_COW_PAGE_SIZE * s->header.header_pages_size > + + (offset_in_bitmap(i * SECTORS_PER_CLUSTER) & (~(c->entry_size - 1))); The maths in this loop looks a bit confusing, but I think it's correct. > + ret = block_cache_get(bs, s->bitmap_cache, offset, > + (void **)&table, BLOCK_TABLE_BITMAP, ADD_COW_CACHE_ENTRY_SIZE); > + if (ret < 0) { > + goto fail; > + } > + if ((table[i / 8] & (1 << (i % 8))) == 0) { > + table[i / 8] |= (1 << (i % 8)); > + block_cache_entry_mark_dirty(s->bitmap_cache, table); > + } Missing block_cache_put again? > + } > + } > + 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; > + bitmap_size = (bitmap_size + ADD_COW_CACHE_ENTRY_SIZE - 1) > + & (~(ADD_COW_CACHE_ENTRY_SIZE - 1)); > + > + ret = bdrv_truncate(bs->file, bitmap_pos + bitmap_size); > + if (ret < 0) { > + return ret; > + } > + return 0; > +} So you don't truncate s->image_file? Does this work? > + > +static coroutine_fn int add_cow_co_flush(BlockDriverState *bs) > +{ > + BDRVAddCowState *s = bs->opaque; > + int ret; > + > + qemu_co_mutex_lock(&s->lock); > + ret = block_cache_flush(bs, s->bitmap_cache, BLOCK_TABLE_BITMAP, > + ADD_COW_CACHE_ENTRY_SIZE); > + qemu_co_mutex_unlock(&s->lock); > + return ret; > +} What about flushing s->image_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_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..f058376 > --- /dev/null > +++ b/block/add-cow.h > @@ -0,0 +1,85 @@ > +/* > + * 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 > +#include "block-cache.h" > + > +enum { > + ADD_COW_F_All_ALLOCATED = 0X01, > + ADD_COW_FEATURE_MASK = 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; Why aren't backing/image_file_format part of the header here? They are in the spec. It would also simplify some offset calculation code. > + > +typedef struct BDRVAddCowState { > + BlockDriverState *image_hd; > + CoMutex lock; > + int cluster_size; > + BlockCache *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; > +} > + > +BlockCache *add_cow_cache_create(BlockDriverState *bs, int num_tables); > +int add_cow_cache_destroy(BlockDriverState *bs, BlockCache *c); > +void add_cow_cache_entry_mark_dirty(BlockCache *c, void *table); > +int add_cow_cache_get(BlockDriverState *bs, BlockCache *c, uint64_t offset, > + void **table); > +int add_cow_cache_flush(BlockDriverState *bs, BlockCache *c); These functions don't really exist any more, do they? Kevin
Am 10.09.2012 04:25, schrieb Dong Xu Wang: > On Fri, Sep 7, 2012 at 4:19 AM, Michael Roth <mdroth@linux.vnet.ibm.com> wrote: >> On Fri, Aug 10, 2012 at 11:39:44PM +0800, Dong Xu Wang wrote: >>> +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; >> >> You should avoid using packed structures for image format headers. >> Instead, I would either: >> >> a) re-order the fields so that 32/64-bit fields, respectively, fall on >> 32/64-bit boundaries (in your case, for instance, moving header_pages_size >> above features) like qed/qcow2 do, or >> >> b) read/write the fields individually rather than reading/writing directly >> into/from the header struct. >> >> The safest route is b). Adds a few lines of code, but you won't have to >> re-work things (or worry about introducing bugs) later if you were to add, >> say, a 32-bit value, and then a 64-bit value later. > > While, Kevin's suggestion is using PACKED, so .. Yes, I think QEMU_PACKED is fine, and it's the safest version. It would be nice to additionally do Michael's option a) if you like, but I don't think the header is accessed too often, so the optimisation isn't that important. Kevin
On Tue, Sep 11, 2012 at 5:40 PM, Kevin Wolf <kwolf@redhat.com> wrote: > Am 10.08.2012 17:39, schrieb Dong Xu Wang: >> add-cow file format core code. It use block-cache.c as cache code. >> >> Signed-off-by: Dong Xu Wang <wdongxu@linux.vnet.ibm.com> >> --- >> block/Makefile.objs | 1 + >> block/add-cow.c | 613 +++++++++++++++++++++++++++++++++++++++++++++++++++ >> block/add-cow.h | 85 +++++++ >> block_int.h | 2 + >> 4 files changed, 701 insertions(+), 0 deletions(-) >> 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 23bdfc8..7ed5051 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 >> 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 >> block-obj-y += block-cache.o >> block-obj-y += parallels.o nbd.o blkdebug.o sheepdog.o blkverify.o >> block-obj-y += stream.o >> diff --git a/block/add-cow.c b/block/add-cow.c >> new file mode 100644 >> index 0000000..d4711d5 >> --- /dev/null >> +++ b/block/add-cow.c >> @@ -0,0 +1,613 @@ >> +/* >> + * 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 image_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"); >> + BDRVAddCowState s; >> + int ret; >> + >> + 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; >> + } else if (!strcmp(options->name, BLOCK_OPT_IMAGE_FORMAT)) { >> + image_format = options->value.s; >> + } >> + options++; >> + } >> + >> + if (backing_filename) { >> + header.backing_filename_offset = sizeof(header) >> + + sizeof(s.backing_file_format) + sizeof(s.image_file_format); >> + 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.image_filename_offset = >> + sizeof(header) + sizeof(s.backing_file_format) >> + + sizeof(s.image_file_format) + header.backing_filename_size; >> + header.image_filename_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_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 ? strlen(backing_fmt) : 0); > > The spec requires zero padding, which you don't do here. Okay. > >> + if (ret < 0) { >> + bdrv_delete(bs); >> + return ret; >> + } >> + >> + ret = bdrv_pwrite(bs, sizeof(le_header) + sizeof(s.backing_file_format), >> + image_format ? image_format : "raw", >> + image_format ? strlen(image_format) : sizeof("raw")); > > And here. Okay. > >> + 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, 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; >> + 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)) { > > if (ret < 0) would be more consistent with the rest of the code. > Okay. >> + goto fail; >> + } >> + >> + add_cow_header_le_to_cpu(&le_header, &s->header); >> + >> + if (le64_to_cpu(s->header.magic) != ADD_COW_MAGIC) { > > Isn't this one endianess conversion too much? s->header is already LE. > > Did you test add-cow on a big endian host? My fault, will correct it in next version. > >> + 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); > > This message is a bit terse, most users will be confused with an error > message that only consists of a hex number. Maybe better "Feature flags: > %" PRIx64. > Okay. >> + qerror_report(QERR_UNKNOWN_BLOCK_FORMAT_FEATURE, >> + bs->device_name, "add-cow", buf); >> + return -ENOTSUP; >> + } >> + >> + if ((s->header.features & ADD_COW_F_All_ALLOCATED) == 0) { >> + ret = bdrv_read_string(bs->file, sizeof(s->header), >> + sizeof(s->backing_file_format) - 1, s->backing_file_format, >> + sizeof(s->backing_file_format)); >> + if (ret < 0) { >> + goto fail; >> + } >> + } > > Would be great if this was not only read into memory, but actually > used... It must end up in bs->backing_format in order take effect. > >> + >> + ret = bdrv_read_string(bs->file, >> + sizeof(s->header) + sizeof(s->image_file_format), >> + sizeof(s->image_file_format) - 1, s->image_file_format, >> + sizeof(s->image_file_format)); >> + if (ret < 0) { >> + goto fail; >> + } > > This one is unused, too. > Okay. >> + >> + 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); > > image_drv is always NULL. > >> + 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; >> + s->bitmap_cache = >> + block_cache_create(bs, ADD_COW_CACHE_SIZE, ADD_COW_CACHE_ENTRY_SIZE); >> + >> + qemu_co_mutex_init(&s->lock); >> + return 0; >> +fail: >> + if (s->bitmap_cache) { >> + block_cache_destroy(bs, s->bitmap_cache, BLOCK_TABLE_BITMAP); >> + } >> + return ret; >> +} >> + >> +static void add_cow_close(BlockDriverState *bs) >> +{ >> + BDRVAddCowState *s = bs->opaque; >> + block_cache_destroy(bs, s->bitmap_cache, BLOCK_TABLE_BITMAP); >> + bdrv_delete(s->image_hd); >> +} >> + >> +static bool is_allocated(BlockDriverState *bs, int64_t sector_num) >> +{ >> + BDRVAddCowState *s = bs->opaque; >> + BlockCache *c = s->bitmap_cache; >> + int64_t cluster_num = sector_num / SECTORS_PER_CLUSTER; >> + uint8_t *table = NULL; >> + uint64_t offset = ADD_COW_PAGE_SIZE * s->header.header_pages_size >> + + (offset_in_bitmap(sector_num) & (~(c->entry_size - 1))); >> + int ret = block_cache_get(bs, s->bitmap_cache, offset, >> + (void **)&table, BLOCK_TABLE_BITMAP, ADD_COW_CACHE_ENTRY_SIZE); > > No matching block_cache_put? > >> + >> + 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; > > Why - 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 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 n, 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, &n)) { >> + cur_nr_sectors = n; > > One of n and cur_nr_sectors is redundant. Okay. > >> + 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); >> + 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, >> + 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; >> + BlockCache *c = s->bitmap_cache; >> + int ret = 0, i; >> + QEMUIOVector hd_qiov; >> + uint8_t *table; >> + uint64_t offset; >> + >> + 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++) { >> + offset = ADD_COW_PAGE_SIZE * s->header.header_pages_size >> + + (offset_in_bitmap(i * SECTORS_PER_CLUSTER) & (~(c->entry_size - 1))); > > The maths in this loop looks a bit confusing, but I think it's correct. > >> + ret = block_cache_get(bs, s->bitmap_cache, offset, >> + (void **)&table, BLOCK_TABLE_BITMAP, ADD_COW_CACHE_ENTRY_SIZE); >> + if (ret < 0) { >> + goto fail; >> + } >> + if ((table[i / 8] & (1 << (i % 8))) == 0) { >> + table[i / 8] |= (1 << (i % 8)); >> + block_cache_entry_mark_dirty(s->bitmap_cache, table); >> + } > > Missing block_cache_put again? > >> + } >> + } >> + 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; >> + bitmap_size = (bitmap_size + ADD_COW_CACHE_ENTRY_SIZE - 1) >> + & (~(ADD_COW_CACHE_ENTRY_SIZE - 1)); >> + >> + ret = bdrv_truncate(bs->file, bitmap_pos + bitmap_size); >> + if (ret < 0) { >> + return ret; >> + } >> + return 0; >> +} > > So you don't truncate s->image_file? Does this work? s->image_file should be truncated? Image file can have a larger virtual size than backing_file, my understanding is we should not truncate image file. > >> + >> +static coroutine_fn int add_cow_co_flush(BlockDriverState *bs) >> +{ >> + BDRVAddCowState *s = bs->opaque; >> + int ret; >> + >> + qemu_co_mutex_lock(&s->lock); >> + ret = block_cache_flush(bs, s->bitmap_cache, BLOCK_TABLE_BITMAP, >> + ADD_COW_CACHE_ENTRY_SIZE); >> + qemu_co_mutex_unlock(&s->lock); >> + return ret; >> +} > > What about flushing s->image_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_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..f058376 >> --- /dev/null >> +++ b/block/add-cow.h >> @@ -0,0 +1,85 @@ >> +/* >> + * 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 >> +#include "block-cache.h" >> + >> +enum { >> + ADD_COW_F_All_ALLOCATED = 0X01, >> + ADD_COW_FEATURE_MASK = 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; > > Why aren't backing/image_file_format part of the header here? They are > in the spec. It would also simplify some offset calculation code. > Anthony said "It's far better to shrink the size of the header and use an offset/len pointer to the backing file string. Limiting backing files to 1023 is unacceptable" http://lists.gnu.org/archive/html/qemu-devel/2012-05/msg04110.html So I use offset and length instead of using string directly. >> + >> +typedef struct BDRVAddCowState { >> + BlockDriverState *image_hd; >> + CoMutex lock; >> + int cluster_size; >> + BlockCache *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; >> +} >> + >> +BlockCache *add_cow_cache_create(BlockDriverState *bs, int num_tables); >> +int add_cow_cache_destroy(BlockDriverState *bs, BlockCache *c); >> +void add_cow_cache_entry_mark_dirty(BlockCache *c, void *table); >> +int add_cow_cache_get(BlockDriverState *bs, BlockCache *c, uint64_t offset, >> + void **table); >> +int add_cow_cache_flush(BlockDriverState *bs, BlockCache *c); > > These functions don't really exist any more, do they? Right, sorry. > > Kevin > Thank you, Kevin.
Am 12.09.2012 09:28, schrieb Dong Xu Wang: >>> +static bool is_allocated(BlockDriverState *bs, int64_t sector_num) >>> +{ >>> + BDRVAddCowState *s = bs->opaque; >>> + BlockCache *c = s->bitmap_cache; >>> + int64_t cluster_num = sector_num / SECTORS_PER_CLUSTER; >>> + uint8_t *table = NULL; >>> + uint64_t offset = ADD_COW_PAGE_SIZE * s->header.header_pages_size >>> + + (offset_in_bitmap(sector_num) & (~(c->entry_size - 1))); >>> + int ret = block_cache_get(bs, s->bitmap_cache, offset, >>> + (void **)&table, BLOCK_TABLE_BITMAP, ADD_COW_CACHE_ENTRY_SIZE); >> >> No matching block_cache_put? >> >>> + >>> + 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; >> >> Why - 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 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; >>> + bitmap_size = (bitmap_size + ADD_COW_CACHE_ENTRY_SIZE - 1) >>> + & (~(ADD_COW_CACHE_ENTRY_SIZE - 1)); >>> + >>> + ret = bdrv_truncate(bs->file, bitmap_pos + bitmap_size); >>> + if (ret < 0) { >>> + return ret; >>> + } >>> + return 0; >>> +} >> >> So you don't truncate s->image_file? Does this work? > > s->image_file should be truncated? Image file can have a larger virtual size > than backing_file, my understanding is we should not truncate image file. I'm talking about s->image_hd, not bs->backing_hd. You are right that the backing file should not be changed. But the associated raw image should be resized, shouldn't it? >>> +static coroutine_fn int add_cow_co_flush(BlockDriverState *bs) >>> +{ >>> + BDRVAddCowState *s = bs->opaque; >>> + int ret; >>> + >>> + qemu_co_mutex_lock(&s->lock); >>> + ret = block_cache_flush(bs, s->bitmap_cache, BLOCK_TABLE_BITMAP, >>> + ADD_COW_CACHE_ENTRY_SIZE); >>> + qemu_co_mutex_unlock(&s->lock); >>> + return ret; >>> +} >> >> What about flushing s->image_file? >>> +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; >> >> Why aren't backing/image_file_format part of the header here? They are >> in the spec. It would also simplify some offset calculation code. >> > > Anthony said "It's far better to shrink the size of the header and use > an offset/len > pointer to the backing file string. Limiting backing files to 1023 is > unacceptable" > > http://lists.gnu.org/archive/html/qemu-devel/2012-05/msg04110.html > > So I use offset and length instead of using string directly. I'm talking about the format, not the path. Kevin
diff --git a/block/Makefile.objs b/block/Makefile.objs index 23bdfc8..7ed5051 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 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 block-obj-y += block-cache.o block-obj-y += parallels.o nbd.o blkdebug.o sheepdog.o blkverify.o block-obj-y += stream.o diff --git a/block/add-cow.c b/block/add-cow.c new file mode 100644 index 0000000..d4711d5 --- /dev/null +++ b/block/add-cow.c @@ -0,0 +1,613 @@ +/* + * 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 image_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"); + BDRVAddCowState s; + int ret; + + 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; + } else if (!strcmp(options->name, BLOCK_OPT_IMAGE_FORMAT)) { + image_format = options->value.s; + } + options++; + } + + if (backing_filename) { + header.backing_filename_offset = sizeof(header) + + sizeof(s.backing_file_format) + sizeof(s.image_file_format); + 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.image_filename_offset = + sizeof(header) + sizeof(s.backing_file_format) + + sizeof(s.image_file_format) + header.backing_filename_size; + header.image_filename_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_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 ? strlen(backing_fmt) : 0); + if (ret < 0) { + bdrv_delete(bs); + return ret; + } + + ret = bdrv_pwrite(bs, sizeof(le_header) + sizeof(s.backing_file_format), + image_format ? image_format : "raw", + image_format ? strlen(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, 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; + 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_All_ALLOCATED) == 0) { + ret = bdrv_read_string(bs->file, sizeof(s->header), + sizeof(s->backing_file_format) - 1, s->backing_file_format, + sizeof(s->backing_file_format)); + if (ret < 0) { + goto fail; + } + } + + ret = bdrv_read_string(bs->file, + sizeof(s->header) + sizeof(s->image_file_format), + sizeof(s->image_file_format) - 1, 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; + } + + 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; + s->bitmap_cache = + block_cache_create(bs, ADD_COW_CACHE_SIZE, ADD_COW_CACHE_ENTRY_SIZE); + + qemu_co_mutex_init(&s->lock); + return 0; +fail: + if (s->bitmap_cache) { + block_cache_destroy(bs, s->bitmap_cache, BLOCK_TABLE_BITMAP); + } + return ret; +} + +static void add_cow_close(BlockDriverState *bs) +{ + BDRVAddCowState *s = bs->opaque; + block_cache_destroy(bs, s->bitmap_cache, BLOCK_TABLE_BITMAP); + bdrv_delete(s->image_hd); +} + +static bool is_allocated(BlockDriverState *bs, int64_t sector_num) +{ + BDRVAddCowState *s = bs->opaque; + BlockCache *c = s->bitmap_cache; + int64_t cluster_num = sector_num / SECTORS_PER_CLUSTER; + uint8_t *table = NULL; + uint64_t offset = ADD_COW_PAGE_SIZE * s->header.header_pages_size + + (offset_in_bitmap(sector_num) & (~(c->entry_size - 1))); + int ret = block_cache_get(bs, s->bitmap_cache, offset, + (void **)&table, BLOCK_TABLE_BITMAP, ADD_COW_CACHE_ENTRY_SIZE); + + 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 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 n, 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, &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); + 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, + 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; + BlockCache *c = s->bitmap_cache; + int ret = 0, i; + QEMUIOVector hd_qiov; + uint8_t *table; + uint64_t offset; + + 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++) { + offset = ADD_COW_PAGE_SIZE * s->header.header_pages_size + + (offset_in_bitmap(i * SECTORS_PER_CLUSTER) & (~(c->entry_size - 1))); + ret = block_cache_get(bs, s->bitmap_cache, offset, + (void **)&table, BLOCK_TABLE_BITMAP, ADD_COW_CACHE_ENTRY_SIZE); + if (ret < 0) { + goto fail; + } + if ((table[i / 8] & (1 << (i % 8))) == 0) { + table[i / 8] |= (1 << (i % 8)); + block_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; + bitmap_size = (bitmap_size + ADD_COW_CACHE_ENTRY_SIZE - 1) + & (~(ADD_COW_CACHE_ENTRY_SIZE - 1)); + + 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 = block_cache_flush(bs, s->bitmap_cache, BLOCK_TABLE_BITMAP, + ADD_COW_CACHE_ENTRY_SIZE); + 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..f058376 --- /dev/null +++ b/block/add-cow.h @@ -0,0 +1,85 @@ +/* + * 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 +#include "block-cache.h" + +enum { + ADD_COW_F_All_ALLOCATED = 0X01, + ADD_COW_FEATURE_MASK = 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 BDRVAddCowState { + BlockDriverState *image_hd; + CoMutex lock; + int cluster_size; + BlockCache *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; +} + +BlockCache *add_cow_cache_create(BlockDriverState *bs, int num_tables); +int add_cow_cache_destroy(BlockDriverState *bs, BlockCache *c); +void add_cow_cache_entry_mark_dirty(BlockCache *c, void *table); +int add_cow_cache_get(BlockDriverState *bs, BlockCache *c, uint64_t offset, + void **table); +int add_cow_cache_flush(BlockDriverState *bs, BlockCache *c); +#endif diff --git a/block_int.h b/block_int.h index 6c1d9ca..67954ec 100644 --- a/block_int.h +++ b/block_int.h @@ -53,6 +53,8 @@ #define BLOCK_OPT_SUBFMT "subformat" #define BLOCK_OPT_COMPAT_LEVEL "compat" #define BLOCK_OPT_LAZY_REFCOUNTS "lazy_refcounts" +#define BLOCK_OPT_IMAGE_FILE "image_file" +#define BLOCK_OPT_IMAGE_FORMAT "image_format" typedef struct BdrvTrackedRequest BdrvTrackedRequest;
add-cow file format core code. It use block-cache.c as cache code. Signed-off-by: Dong Xu Wang <wdongxu@linux.vnet.ibm.com> --- block/Makefile.objs | 1 + block/add-cow.c | 613 +++++++++++++++++++++++++++++++++++++++++++++++++++ block/add-cow.h | 85 +++++++ block_int.h | 2 + 4 files changed, 701 insertions(+), 0 deletions(-) create mode 100644 block/add-cow.c create mode 100644 block/add-cow.h