* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
-#ifndef _WIN32
#include "qemu-common.h"
-#include "block_int.h"
-#include "module.h"
-#include <sys/mman.h>
+#include "block/block_int.h"
+#include "qemu/module.h"
/**************************************************************/
/* COW block driver using file system holes */
};
typedef struct BDRVCowState {
- int fd;
- uint8_t *cow_bitmap; /* if non NULL, COW mappings are used first */
- uint8_t *cow_bitmap_addr; /* mmap address of cow_bitmap */
- int cow_bitmap_size;
+ CoMutex lock;
int64_t cow_sectors_offset;
} BDRVCowState;
return 0;
}
-static int cow_open(BlockDriverState *bs, const char *filename, int flags)
+static int cow_open(BlockDriverState *bs, QDict *options, int flags,
+ Error **errp)
{
BDRVCowState *s = bs->opaque;
- int fd;
struct cow_header_v2 cow_header;
+ int bitmap_size;
int64_t size;
+ int ret;
- fd = open(filename, O_RDWR | O_BINARY | O_LARGEFILE);
- if (fd < 0) {
- fd = open(filename, O_RDONLY | O_BINARY | O_LARGEFILE);
- if (fd < 0)
- return -1;
- }
- s->fd = fd;
/* see if it is a cow image */
- if (pread(fd, &cow_header, sizeof(cow_header), 0) != sizeof(cow_header)) {
+ 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) {
+ ret = -EMEDIUMTYPE;
goto fail;
}
- if (be32_to_cpu(cow_header.magic) != COW_MAGIC ||
- be32_to_cpu(cow_header.version) != COW_VERSION) {
+ if (be32_to_cpu(cow_header.version) != COW_VERSION) {
+ char version[64];
+ snprintf(version, sizeof(version),
+ "COW version %d", cow_header.version);
+ qerror_report(QERR_UNKNOWN_BLOCK_FORMAT_FEATURE,
+ bs->device_name, "cow", version);
+ ret = -ENOTSUP;
goto fail;
}
pstrcpy(bs->backing_file, sizeof(bs->backing_file),
cow_header.backing_file);
- /* mmap the bitmap */
- s->cow_bitmap_size = ((bs->total_sectors + 7) >> 3) + sizeof(cow_header);
- s->cow_bitmap_addr = (void *)mmap(get_mmap_addr(s->cow_bitmap_size),
- s->cow_bitmap_size,
- PROT_READ | PROT_WRITE,
- MAP_SHARED, s->fd, 0);
- if (s->cow_bitmap_addr == MAP_FAILED)
- goto fail;
- s->cow_bitmap = s->cow_bitmap_addr + sizeof(cow_header);
- s->cow_sectors_offset = (s->cow_bitmap_size + 511) & ~511;
+ 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:
- close(fd);
- return -1;
+ return ret;
}
-static inline void cow_set_bit(uint8_t *bitmap, int64_t bitnum)
+/*
+ * XXX(hch): right now these functions are extremely inefficient.
+ * We should just read the whole bitmap we'll need in one go instead.
+ */
+static inline int cow_set_bit(BlockDriverState *bs, int64_t bitnum, bool *first)
{
- bitmap[bitnum / 8] |= (1 << (bitnum%8));
+ uint64_t offset = sizeof(struct cow_header_v2) + bitnum / 8;
+ uint8_t bitmap;
+ int ret;
+
+ ret = bdrv_pread(bs->file, offset, &bitmap, sizeof(bitmap));
+ if (ret < 0) {
+ return ret;
+ }
+
+ if (bitmap & (1 << (bitnum % 8))) {
+ return 0;
+ }
+
+ if (*first) {
+ ret = bdrv_flush(bs->file);
+ if (ret < 0) {
+ return ret;
+ }
+ *first = false;
+ }
+
+ bitmap |= (1 << (bitnum % 8));
+
+ ret = bdrv_pwrite(bs->file, offset, &bitmap, sizeof(bitmap));
+ if (ret < 0) {
+ return ret;
+ }
+ return 0;
}
-static inline int is_bit_set(const uint8_t *bitmap, int64_t 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%8)));
+ 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 inline int is_changed(uint8_t *bitmap,
- int64_t sector_num, int nb_sectors,
- int *num_same)
+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;
+ uint8_t bitmap[BDRV_SECTOR_SIZE];
+ int ret;
int changed;
- if (!bitmap || nb_sectors == 0) {
- *num_same = nb_sectors;
- return 0;
- }
-
- changed = is_bit_set(bitmap, sector_num);
- for (*num_same = 1; *num_same < nb_sectors; (*num_same)++) {
- if (is_bit_set(bitmap, sector_num + *num_same) != changed)
- break;
+ ret = bdrv_pread(bs->file, offset, &bitmap, sizeof(bitmap));
+ if (ret < 0) {
+ return ret;
}
+ bitnum &= BITS_PER_BITMAP_SECTOR - 1;
+ changed = cow_test_bit(bitnum, bitmap);
+ *num_same = cow_find_streak(bitmap, changed, bitnum, nb_sectors);
return changed;
}
-static int cow_is_allocated(BlockDriverState *bs, int64_t sector_num,
- int nb_sectors, int *pnum)
+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;
- return is_changed(s->cow_bitmap, sector_num, nb_sectors, pnum);
+ 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)
+{
+ int error = 0;
+ int i;
+ bool first = true;
+
+ for (i = 0; i < nb_sectors; i++) {
+ error = cow_set_bit(bs, sector_num + i, &first);
+ if (error) {
+ break;
+ }
+ }
+
+ return error;
}
-static int cow_read(BlockDriverState *bs, int64_t sector_num,
- uint8_t *buf, int nb_sectors)
+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) {
- if (is_changed(s->cow_bitmap, sector_num, nb_sectors, &n)) {
- ret = pread(s->fd, buf, n * 512,
- s->cow_sectors_offset + sector_num * 512);
- if (ret != n * 512)
- return -1;
+ 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 -1;
+ if (ret < 0) {
+ return ret;
+ }
} else {
- memset(buf, 0, n * 512);
- }
+ memset(buf, 0, n * 512);
+ }
}
nb_sectors -= n;
sector_num += n;
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, i;
-
- ret = pwrite(s->fd, buf, nb_sectors * 512,
- s->cow_sectors_offset + sector_num * 512);
- if (ret != nb_sectors * 512)
- return -1;
- for (i = 0; i < nb_sectors; i++)
- cow_set_bit(s->cow_bitmap, sector_num + i);
- return 0;
+ 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 void cow_close(BlockDriverState *bs)
+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;
- munmap((void *)s->cow_bitmap_addr, s->cow_bitmap_size);
- close(s->fd);
+ 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, QEMUOptionParameter *options)
+static int cow_create(const char *filename, QEMUOptionParameter *options,
+ Error **errp)
{
- int fd, cow_fd;
struct cow_header_v2 cow_header;
struct stat st;
int64_t image_sectors = 0;
const char *image_filename = NULL;
+ Error *local_err = NULL;
int ret;
+ BlockDriverState *cow_bs;
/* Read out options */
while (options && options->name) {
options++;
}
- cow_fd = open(filename, O_WRONLY | O_CREAT | O_TRUNC | O_BINARY,
- 0644);
- if (cow_fd < 0)
- return -errno;
+ ret = bdrv_create_file(filename, options);
+ if (ret < 0) {
+ return ret;
+ }
+
+ ret = bdrv_file_open(&cow_bs, filename, NULL, BDRV_O_RDWR, &local_err);
+ if (ret < 0) {
+ qerror_report_err(local_err);
+ error_free(local_err);
+ return ret;
+ }
+
memset(&cow_header, 0, sizeof(cow_header));
cow_header.magic = cpu_to_be32(COW_MAGIC);
cow_header.version = cpu_to_be32(COW_VERSION);
/* Note: if no file, we put a dummy mtime */
cow_header.mtime = cpu_to_be32(0);
- fd = open(image_filename, O_RDONLY | O_BINARY);
- if (fd < 0) {
- close(cow_fd);
+ if (stat(image_filename, &st) != 0) {
goto mtime_fail;
}
- if (fstat(fd, &st) != 0) {
- close(fd);
- goto mtime_fail;
- }
- close(fd);
cow_header.mtime = cpu_to_be32(st.st_mtime);
mtime_fail:
pstrcpy(cow_header.backing_file, sizeof(cow_header.backing_file),
}
cow_header.sectorsize = cpu_to_be32(512);
cow_header.size = cpu_to_be64(image_sectors * 512);
- ret = qemu_write_full(cow_fd, &cow_header, sizeof(cow_header));
- if (ret != sizeof(cow_header)) {
- ret = -errno;
+ 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 = ftruncate(cow_fd, sizeof(cow_header) + ((image_sectors + 7) >> 3));
- if (ret) {
- ret = -errno;
+ ret = bdrv_truncate(cow_bs,
+ sizeof(cow_header) + ((image_sectors + 7) >> 3));
+ if (ret < 0) {
goto exit;
}
exit:
- close(cow_fd);
+ bdrv_unref(cow_bs);
return ret;
}
-static void cow_flush(BlockDriverState *bs)
-{
- BDRVCowState *s = bs->opaque;
- qemu_fdatasync(s->fd);
-}
-
static QEMUOptionParameter cow_create_options[] = {
{
.name = BLOCK_OPT_SIZE,
};
static BlockDriver bdrv_cow = {
- .format_name = "cow",
- .instance_size = sizeof(BDRVCowState),
- .bdrv_probe = cow_probe,
- .bdrv_file_open = cow_open,
- .bdrv_read = cow_read,
- .bdrv_write = cow_write,
- .bdrv_close = cow_close,
- .bdrv_create = cow_create,
- .bdrv_flush = cow_flush,
- .bdrv_is_allocated = cow_is_allocated,
+ .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,
+
+ .bdrv_read = cow_co_read,
+ .bdrv_write = cow_co_write,
+ .bdrv_co_get_block_status = cow_co_get_block_status,
.create_options = cow_create_options,
};
}
block_init(bdrv_cow_init);
-#endif
projects / mirror_qemu.git / blobdiff