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-rw-r--r--block/cow.c433
1 files changed, 0 insertions, 433 deletions
diff --git a/block/cow.c b/block/cow.c
deleted file mode 100644
index c3769fe03b..0000000000
--- a/block/cow.c
+++ /dev/null
@@ -1,433 +0,0 @@
-/*
- * Block driver for the COW format
- *
- * Copyright (c) 2004 Fabrice Bellard
- *
- * Permission is hereby granted, free of charge, to any person obtaining a copy
- * of this software and associated documentation files (the "Software"), to deal
- * in the Software without restriction, including without limitation the rights
- * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
- * copies of the Software, and to permit persons to whom the Software is
- * furnished to do so, subject to the following conditions:
- *
- * The above copyright notice and this permission notice shall be included in
- * all copies or substantial portions of the Software.
- *
- * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
- * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
- * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
- * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
- * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
- * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
- * THE SOFTWARE.
- */
-#include "qemu-common.h"
-#include "block/block_int.h"
-#include "qemu/module.h"
-
-/**************************************************************/
-/* COW block driver using file system holes */
-
-/* user mode linux compatible COW file */
-#define COW_MAGIC 0x4f4f4f4d /* MOOO */
-#define COW_VERSION 2
-
-struct cow_header_v2 {
- uint32_t magic;
- uint32_t version;
- char backing_file[1024];
- int32_t mtime;
- uint64_t size;
- uint32_t sectorsize;
-};
-
-typedef struct BDRVCowState {
- CoMutex lock;
- int64_t cow_sectors_offset;
-} BDRVCowState;
-
-static int cow_probe(const uint8_t *buf, int buf_size, const char *filename)
-{
- const struct cow_header_v2 *cow_header = (const void *)buf;
-
- if (buf_size >= sizeof(struct cow_header_v2) &&
- be32_to_cpu(cow_header->magic) == COW_MAGIC &&
- be32_to_cpu(cow_header->version) == COW_VERSION)
- return 100;
- else
- return 0;
-}
-
-static int cow_open(BlockDriverState *bs, QDict *options, int flags,
- Error **errp)
-{
- BDRVCowState *s = bs->opaque;
- struct cow_header_v2 cow_header;
- int bitmap_size;
- int64_t size;
- int ret;
-
- /* see if it is a cow image */
- ret = bdrv_pread(bs->file, 0, &cow_header, sizeof(cow_header));
- if (ret < 0) {
- goto fail;
- }
-
- if (be32_to_cpu(cow_header.magic) != COW_MAGIC) {
- error_setg(errp, "Image not in COW format");
- ret = -EINVAL;
- goto fail;
- }
-
- if (be32_to_cpu(cow_header.version) != COW_VERSION) {
- char version[64];
- snprintf(version, sizeof(version),
- "COW version %" PRIu32, cow_header.version);
- error_set(errp, QERR_UNKNOWN_BLOCK_FORMAT_FEATURE,
- bs->device_name, "cow", version);
- ret = -ENOTSUP;
- goto fail;
- }
-
- /* cow image found */
- size = be64_to_cpu(cow_header.size);
- bs->total_sectors = size / 512;
-
- pstrcpy(bs->backing_file, sizeof(bs->backing_file),
- cow_header.backing_file);
-
- bitmap_size = ((bs->total_sectors + 7) >> 3) + sizeof(cow_header);
- s->cow_sectors_offset = (bitmap_size + 511) & ~511;
- qemu_co_mutex_init(&s->lock);
- return 0;
- fail:
- return ret;
-}
-
-static inline void cow_set_bits(uint8_t *bitmap, int start, int64_t nb_sectors)
-{
- int64_t bitnum = start, last = start + nb_sectors;
- while (bitnum < last) {
- if ((bitnum & 7) == 0 && bitnum + 8 <= last) {
- bitmap[bitnum / 8] = 0xFF;
- bitnum += 8;
- continue;
- }
- bitmap[bitnum/8] |= (1 << (bitnum % 8));
- bitnum++;
- }
-}
-
-#define BITS_PER_BITMAP_SECTOR (512 * 8)
-
-/* Cannot use bitmap.c on big-endian machines. */
-static int cow_test_bit(int64_t bitnum, const uint8_t *bitmap)
-{
- return (bitmap[bitnum / 8] & (1 << (bitnum & 7))) != 0;
-}
-
-static int cow_find_streak(const uint8_t *bitmap, int value, int start, int nb_sectors)
-{
- int streak_value = value ? 0xFF : 0;
- int last = MIN(start + nb_sectors, BITS_PER_BITMAP_SECTOR);
- int bitnum = start;
- while (bitnum < last) {
- if ((bitnum & 7) == 0 && bitmap[bitnum / 8] == streak_value) {
- bitnum += 8;
- continue;
- }
- if (cow_test_bit(bitnum, bitmap) == value) {
- bitnum++;
- continue;
- }
- break;
- }
- return MIN(bitnum, last) - start;
-}
-
-/* Return true if first block has been changed (ie. current version is
- * in COW file). Set the number of continuous blocks for which that
- * is true. */
-static int coroutine_fn cow_co_is_allocated(BlockDriverState *bs,
- int64_t sector_num, int nb_sectors, int *num_same)
-{
- int64_t bitnum = sector_num + sizeof(struct cow_header_v2) * 8;
- uint64_t offset = (bitnum / 8) & -BDRV_SECTOR_SIZE;
- bool first = true;
- int changed = 0, same = 0;
-
- do {
- int ret;
- uint8_t bitmap[BDRV_SECTOR_SIZE];
-
- bitnum &= BITS_PER_BITMAP_SECTOR - 1;
- int sector_bits = MIN(nb_sectors, BITS_PER_BITMAP_SECTOR - bitnum);
-
- ret = bdrv_pread(bs->file, offset, &bitmap, sizeof(bitmap));
- if (ret < 0) {
- return ret;
- }
-
- if (first) {
- changed = cow_test_bit(bitnum, bitmap);
- first = false;
- }
-
- same += cow_find_streak(bitmap, changed, bitnum, nb_sectors);
-
- bitnum += sector_bits;
- nb_sectors -= sector_bits;
- offset += BDRV_SECTOR_SIZE;
- } while (nb_sectors);
-
- *num_same = same;
- return changed;
-}
-
-static int64_t coroutine_fn cow_co_get_block_status(BlockDriverState *bs,
- int64_t sector_num, int nb_sectors, int *num_same)
-{
- BDRVCowState *s = bs->opaque;
- int ret = cow_co_is_allocated(bs, sector_num, nb_sectors, num_same);
- int64_t offset = s->cow_sectors_offset + (sector_num << BDRV_SECTOR_BITS);
- if (ret < 0) {
- return ret;
- }
- return (ret ? BDRV_BLOCK_DATA : 0) | offset | BDRV_BLOCK_OFFSET_VALID;
-}
-
-static int cow_update_bitmap(BlockDriverState *bs, int64_t sector_num,
- int nb_sectors)
-{
- int64_t bitnum = sector_num + sizeof(struct cow_header_v2) * 8;
- uint64_t offset = (bitnum / 8) & -BDRV_SECTOR_SIZE;
- bool first = true;
- int sector_bits;
-
- for ( ; nb_sectors;
- bitnum += sector_bits,
- nb_sectors -= sector_bits,
- offset += BDRV_SECTOR_SIZE) {
- int ret, set;
- uint8_t bitmap[BDRV_SECTOR_SIZE];
-
- bitnum &= BITS_PER_BITMAP_SECTOR - 1;
- sector_bits = MIN(nb_sectors, BITS_PER_BITMAP_SECTOR - bitnum);
-
- ret = bdrv_pread(bs->file, offset, &bitmap, sizeof(bitmap));
- if (ret < 0) {
- return ret;
- }
-
- /* Skip over any already set bits */
- set = cow_find_streak(bitmap, 1, bitnum, sector_bits);
- bitnum += set;
- sector_bits -= set;
- nb_sectors -= set;
- if (!sector_bits) {
- continue;
- }
-
- if (first) {
- ret = bdrv_flush(bs->file);
- if (ret < 0) {
- return ret;
- }
- first = false;
- }
-
- cow_set_bits(bitmap, bitnum, sector_bits);
-
- ret = bdrv_pwrite(bs->file, offset, &bitmap, sizeof(bitmap));
- if (ret < 0) {
- return ret;
- }
- }
-
- return 0;
-}
-
-static int coroutine_fn cow_read(BlockDriverState *bs, int64_t sector_num,
- uint8_t *buf, int nb_sectors)
-{
- BDRVCowState *s = bs->opaque;
- int ret, n;
-
- while (nb_sectors > 0) {
- ret = cow_co_is_allocated(bs, sector_num, nb_sectors, &n);
- if (ret < 0) {
- return ret;
- }
- if (ret) {
- ret = bdrv_pread(bs->file,
- s->cow_sectors_offset + sector_num * 512,
- buf, n * 512);
- if (ret < 0) {
- return ret;
- }
- } else {
- if (bs->backing_hd) {
- /* read from the base image */
- ret = bdrv_read(bs->backing_hd, sector_num, buf, n);
- if (ret < 0) {
- return ret;
- }
- } else {
- memset(buf, 0, n * 512);
- }
- }
- nb_sectors -= n;
- sector_num += n;
- buf += n * 512;
- }
- return 0;
-}
-
-static coroutine_fn int cow_co_read(BlockDriverState *bs, int64_t sector_num,
- uint8_t *buf, int nb_sectors)
-{
- int ret;
- BDRVCowState *s = bs->opaque;
- qemu_co_mutex_lock(&s->lock);
- ret = cow_read(bs, sector_num, buf, nb_sectors);
- qemu_co_mutex_unlock(&s->lock);
- return ret;
-}
-
-static int cow_write(BlockDriverState *bs, int64_t sector_num,
- const uint8_t *buf, int nb_sectors)
-{
- BDRVCowState *s = bs->opaque;
- int ret;
-
- ret = bdrv_pwrite(bs->file, s->cow_sectors_offset + sector_num * 512,
- buf, nb_sectors * 512);
- if (ret < 0) {
- return ret;
- }
-
- return cow_update_bitmap(bs, sector_num, nb_sectors);
-}
-
-static coroutine_fn int cow_co_write(BlockDriverState *bs, int64_t sector_num,
- const uint8_t *buf, int nb_sectors)
-{
- int ret;
- BDRVCowState *s = bs->opaque;
- qemu_co_mutex_lock(&s->lock);
- ret = cow_write(bs, sector_num, buf, nb_sectors);
- qemu_co_mutex_unlock(&s->lock);
- return ret;
-}
-
-static void cow_close(BlockDriverState *bs)
-{
-}
-
-static int cow_create(const char *filename, QemuOpts *opts, Error **errp)
-{
- struct cow_header_v2 cow_header;
- struct stat st;
- int64_t image_sectors = 0;
- char *image_filename = NULL;
- Error *local_err = NULL;
- int ret;
- BlockDriverState *cow_bs = NULL;
-
- /* Read out options */
- image_sectors = DIV_ROUND_UP(qemu_opt_get_size_del(opts, BLOCK_OPT_SIZE, 0),
- BDRV_SECTOR_SIZE);
- image_filename = qemu_opt_get_del(opts, BLOCK_OPT_BACKING_FILE);
-
- ret = bdrv_create_file(filename, opts, &local_err);
- if (ret < 0) {
- error_propagate(errp, local_err);
- goto exit;
- }
-
- ret = bdrv_open(&cow_bs, filename, NULL, NULL,
- BDRV_O_RDWR | BDRV_O_PROTOCOL, NULL, &local_err);
- if (ret < 0) {
- error_propagate(errp, local_err);
- goto exit;
- }
-
- memset(&cow_header, 0, sizeof(cow_header));
- cow_header.magic = cpu_to_be32(COW_MAGIC);
- cow_header.version = cpu_to_be32(COW_VERSION);
- if (image_filename) {
- /* Note: if no file, we put a dummy mtime */
- cow_header.mtime = cpu_to_be32(0);
-
- if (stat(image_filename, &st) != 0) {
- goto mtime_fail;
- }
- cow_header.mtime = cpu_to_be32(st.st_mtime);
- mtime_fail:
- pstrcpy(cow_header.backing_file, sizeof(cow_header.backing_file),
- image_filename);
- }
- cow_header.sectorsize = cpu_to_be32(512);
- cow_header.size = cpu_to_be64(image_sectors * 512);
- ret = bdrv_pwrite(cow_bs, 0, &cow_header, sizeof(cow_header));
- if (ret < 0) {
- goto exit;
- }
-
- /* resize to include at least all the bitmap */
- ret = bdrv_truncate(cow_bs,
- sizeof(cow_header) + ((image_sectors + 7) >> 3));
- if (ret < 0) {
- goto exit;
- }
-
-exit:
- g_free(image_filename);
- if (cow_bs) {
- bdrv_unref(cow_bs);
- }
- return ret;
-}
-
-static QemuOptsList cow_create_opts = {
- .name = "cow-create-opts",
- .head = QTAILQ_HEAD_INITIALIZER(cow_create_opts.head),
- .desc = {
- {
- .name = BLOCK_OPT_SIZE,
- .type = QEMU_OPT_SIZE,
- .help = "Virtual disk size"
- },
- {
- .name = BLOCK_OPT_BACKING_FILE,
- .type = QEMU_OPT_STRING,
- .help = "File name of a base image"
- },
- { /* end of list */ }
- }
-};
-
-static BlockDriver bdrv_cow = {
- .format_name = "cow",
- .instance_size = sizeof(BDRVCowState),
-
- .bdrv_probe = cow_probe,
- .bdrv_open = cow_open,
- .bdrv_close = cow_close,
- .bdrv_create = cow_create,
- .bdrv_has_zero_init = bdrv_has_zero_init_1,
- .supports_backing = true,
-
- .bdrv_read = cow_co_read,
- .bdrv_write = cow_co_write,
- .bdrv_co_get_block_status = cow_co_get_block_status,
-
- .create_opts = &cow_create_opts,
-};
-
-static void bdrv_cow_init(void)
-{
- bdrv_register(&bdrv_cow);
-}
-
-block_init(bdrv_cow_init);
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