From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:59645) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1VoyPO-0007Ti-Kx for qemu-devel@nongnu.org; Fri, 06 Dec 2013 11:37:48 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1VoyPI-0003Pc-Ku for qemu-devel@nongnu.org; Fri, 06 Dec 2013 11:37:42 -0500 Received: from mx1.redhat.com ([209.132.183.28]:37395) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1VoyPI-0003PU-Cd for qemu-devel@nongnu.org; Fri, 06 Dec 2013 11:37:36 -0500 From: Stefan Hajnoczi Date: Fri, 6 Dec 2013 17:36:16 +0100 Message-Id: <1386347807-27359-18-git-send-email-stefanha@redhat.com> In-Reply-To: <1386347807-27359-1-git-send-email-stefanha@redhat.com> References: <1386347807-27359-1-git-send-email-stefanha@redhat.com> Subject: [Qemu-devel] [PULL 17/48] raw-posix: implement write_zeroes with MAY_UNMAP for block devices List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: Paolo Bonzini , Stefan Hajnoczi , Anthony Liguori From: Paolo Bonzini See the next commit for the description of the Linux kernel problem that is worked around in raw_open_common. Signed-off-by: Paolo Bonzini Signed-off-by: Stefan Hajnoczi --- block/raw-posix.c | 37 +++++++++++++++++++++++++++++++++++++ 1 file changed, 37 insertions(+) diff --git a/block/raw-posix.c b/block/raw-posix.c index 7f3f47d..b3feed6 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, -- 1.8.4.2