diff options
Diffstat (limited to 'block')
| -rw-r--r-- | block/raw-posix.c | 37 |
1 files changed, 37 insertions, 0 deletions
diff --git a/block/raw-posix.c b/block/raw-posix.c index 7f3f47d699..b3feed611b 100644 --- a/block/raw-posix.c +++ b/block/raw-posix.c @@ -334,6 +334,22 @@ static int raw_open_common(BlockDriverState *bs, QDict *options, if (S_ISREG(st.st_mode)) { s->discard_zeroes = true; } + if (S_ISBLK(st.st_mode)) { +#ifdef BLKDISCARDZEROES + unsigned int arg; + if (ioctl(s->fd, BLKDISCARDZEROES, &arg) == 0 && arg) { + s->discard_zeroes = true; + } +#endif +#ifdef __linux__ + /* On Linux 3.10, BLKDISCARD leaves stale data in the page cache. Do + * not rely on the contents of discarded blocks unless using O_DIRECT. + */ + if (!(bs->open_flags & BDRV_O_NOCACHE)) { + s->discard_zeroes = false; + } +#endif + } #ifdef CONFIG_XFS if (platform_test_xfs_fd(s->fd)) { @@ -1586,6 +1602,26 @@ static coroutine_fn BlockDriverAIOCB *hdev_aio_discard(BlockDriverState *bs, cb, opaque, QEMU_AIO_DISCARD|QEMU_AIO_BLKDEV); } +static coroutine_fn int hdev_co_write_zeroes(BlockDriverState *bs, + int64_t sector_num, int nb_sectors, BdrvRequestFlags flags) +{ + BDRVRawState *s = bs->opaque; + int rc; + + rc = fd_open(bs); + if (rc < 0) { + return rc; + } + if (!(flags & BDRV_REQ_MAY_UNMAP)) { + return -ENOTSUP; + } + if (!s->discard_zeroes) { + return -ENOTSUP; + } + return paio_submit_co(bs, s->fd, sector_num, NULL, nb_sectors, + QEMU_AIO_DISCARD|QEMU_AIO_BLKDEV); +} + static int hdev_create(const char *filename, QEMUOptionParameter *options, Error **errp) { @@ -1638,6 +1674,7 @@ static BlockDriver bdrv_host_device = { .bdrv_reopen_abort = raw_reopen_abort, .bdrv_create = hdev_create, .create_options = raw_create_options, + .bdrv_co_write_zeroes = hdev_co_write_zeroes, .bdrv_aio_readv = raw_aio_readv, .bdrv_aio_writev = raw_aio_writev, |