return 0;
}
-static int cow_open(BlockDriverState *bs, QDict *options, int flags)
+static int cow_open(BlockDriverState *bs, QDict *options, int flags,
+ Error **errp)
{
BDRVCowState *s = bs->opaque;
struct cow_header_v2 cow_header;
}
if (be32_to_cpu(cow_header.magic) != COW_MAGIC) {
- ret = -EMEDIUMTYPE;
+ error_setg(errp, "Image not in COW format");
+ ret = -EINVAL;
goto fail;
}
char version[64];
snprintf(version, sizeof(version),
"COW version %d", cow_header.version);
- qerror_report(QERR_UNKNOWN_BLOCK_FORMAT_FEATURE,
+ error_set(errp, QERR_UNKNOWN_BLOCK_FORMAT_FEATURE,
bs->device_name, "cow", version);
ret = -ENOTSUP;
goto fail;
return ret;
}
-/*
- * 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)
+static inline void cow_set_bits(uint8_t *bitmap, int start, int64_t nb_sectors)
{
- 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;
+ 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++;
}
+}
- bitmap |= (1 << (bitnum % 8));
+#define BITS_PER_BITMAP_SECTOR (512 * 8)
- ret = bdrv_pwrite_sync(bs->file, offset, &bitmap, sizeof(bitmap));
- if (ret < 0) {
- return ret;
- }
- return 0;
+/* 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 inline int is_bit_set(BlockDriverState *bs, int64_t bitnum)
+static int cow_find_streak(const uint8_t *bitmap, int value, int start, int nb_sectors)
{
- 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;
+ 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 !!(bitmap & (1 << (bitnum % 8)));
+ return MIN(bitnum, last) - start;
}
/* Return true if first block has been changed (ie. current version is
static int coroutine_fn cow_co_is_allocated(BlockDriverState *bs,
int64_t sector_num, int nb_sectors, int *num_same)
{
- int changed;
+ 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;
- if (nb_sectors == 0) {
- *num_same = nb_sectors;
- return 0;
- }
+ do {
+ int ret;
+ uint8_t bitmap[BDRV_SECTOR_SIZE];
- changed = is_bit_set(bs, sector_num);
- if (changed < 0) {
- return 0; /* XXX: how to return I/O errors? */
- }
+ bitnum &= BITS_PER_BITMAP_SECTOR - 1;
+ int sector_bits = MIN(nb_sectors, BITS_PER_BITMAP_SECTOR - bitnum);
- for (*num_same = 1; *num_same < nb_sectors; (*num_same)++) {
- if (is_bit_set(bs, sector_num + *num_same) != changed)
- break;
- }
+ 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)
{
- int error = 0;
- int i;
+ 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;
+ }
- for (i = 0; i < nb_sectors; i++) {
- error = cow_set_bit(bs, sector_num + i);
- if (error) {
- break;
+ 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 error;
+ return 0;
}
static int coroutine_fn cow_read(BlockDriverState *bs, int64_t sector_num,
int ret, n;
while (nb_sectors > 0) {
- if (bdrv_co_is_allocated(bs, sector_num, nb_sectors, &n)) {
+ 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);
{
}
-static int cow_create(const char *filename, QEMUOptionParameter *options)
+static int cow_create(const char *filename, QEMUOptionParameter *options,
+ Error **errp)
{
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;
options++;
}
- ret = bdrv_create_file(filename, options);
+ ret = bdrv_create_file(filename, options, &local_err);
if (ret < 0) {
+ error_propagate(errp, local_err);
return ret;
}
- ret = bdrv_file_open(&cow_bs, filename, NULL, BDRV_O_RDWR);
+ cow_bs = NULL;
+ 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);
return ret;
}
}
exit:
- bdrv_delete(cow_bs);
+ bdrv_unref(cow_bs);
return ret;
}
.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_is_allocated = cow_co_is_allocated,
+ .bdrv_co_get_block_status = cow_co_get_block_status,
.create_options = cow_create_options,
};
projects / qemu.git / blobdiff