diff options
| -rw-r--r-- | block.c | 37 | ||||
| -rw-r--r-- | include/block/block.h | 1 |
2 files changed, 38 insertions, 0 deletions
@@ -2399,6 +2399,43 @@ int bdrv_write_zeroes(BlockDriverState *bs, int64_t sector_num, BDRV_REQ_ZERO_WRITE | flags); } +/* + * Completely zero out a block device with the help of bdrv_write_zeroes. + * The operation is sped up by checking the block status and only writing + * zeroes to the device if they currently do not return zeroes. Optional + * flags are passed through to bdrv_write_zeroes (e.g. BDRV_REQ_MAY_UNMAP). + * + * Returns < 0 on error, 0 on success. For error codes see bdrv_write(). + */ +int bdrv_make_zero(BlockDriverState *bs, BdrvRequestFlags flags) +{ + int64_t target_size = bdrv_getlength(bs) / BDRV_SECTOR_SIZE; + int64_t ret, nb_sectors, sector_num = 0; + int n; + + for (;;) { + nb_sectors = target_size - sector_num; + if (nb_sectors <= 0) { + return 0; + } + if (nb_sectors > INT_MAX) { + nb_sectors = INT_MAX; + } + ret = bdrv_get_block_status(bs, sector_num, nb_sectors, &n); + if (ret & BDRV_BLOCK_ZERO) { + sector_num += n; + continue; + } + ret = bdrv_write_zeroes(bs, sector_num, n, flags); + if (ret < 0) { + error_report("error writing zeroes at sector %" PRId64 ": %s", + sector_num, strerror(-ret)); + return ret; + } + sector_num += n; + } +} + int bdrv_pread(BlockDriverState *bs, int64_t offset, void *buf, int count1) { diff --git a/include/block/block.h b/include/block/block.h index 803c5caceb..4d9e67c7eb 100644 --- a/include/block/block.h +++ b/include/block/block.h @@ -216,6 +216,7 @@ int bdrv_write(BlockDriverState *bs, int64_t sector_num, const uint8_t *buf, int nb_sectors); int bdrv_write_zeroes(BlockDriverState *bs, int64_t sector_num, int nb_sectors, BdrvRequestFlags flags); +int bdrv_make_zero(BlockDriverState *bs, BdrvRequestFlags flags); int bdrv_writev(BlockDriverState *bs, int64_t sector_num, QEMUIOVector *qiov); int bdrv_pread(BlockDriverState *bs, int64_t offset, void *buf, int count); |