From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:43836) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Vqr1i-0007Dp-U7 for qemu-devel@nongnu.org; Wed, 11 Dec 2013 16:09:09 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Vqr1X-0000fs-VQ for qemu-devel@nongnu.org; Wed, 11 Dec 2013 16:09:02 -0500 Received: from mx1.redhat.com ([209.132.183.28]:28650) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Vqr1X-0000ff-MX for qemu-devel@nongnu.org; Wed, 11 Dec 2013 16:08:51 -0500 From: Kevin Wolf Date: Wed, 11 Dec 2013 22:08:07 +0100 Message-Id: <1386796109-15264-1-git-send-email-kwolf@redhat.com> Subject: [Qemu-devel] [PATCH 00/22] block: Support for 512b-on-4k emulation List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: kwolf@redhat.com, pbonzini@redhat.com, pl@kamp.de, stefanha@redhat.com This patch series adds code to the block layer that allows performing I/O requests in smaller granularities than required by the host backend (most importantly, O_DIRECT restrictions). It achieves this for reads by rounding the request to host-side block boundary, and for writes by performing a read-modify-write cycle (and serialising requests touching the same block so that the RMW doesn't write back stale data). Originally I intended to reuse a lot of code from Paolo's previous patch series, however as I tried to integrate pread/pwrite, which already do a very similar thing (except for considering concurrency), and because I wanted to implement zero-copy, most of this series ended up being new code. Zero-copy is possible in a common case because while XFS defauls to a 4k sector size and therefore 4k on-disk O_DIRECT alignment for 512E disks, it still only has a 512 byte memory alignment requirement. (Unfortunately the XFS_IOC_DIOINFO ioctl claims 4k even for memory, but we know that the value is wrong and can probe it.) Changes since RFC: - Moved opt_mem_alignment into BlockLimits [Paolo] - Changed BlockLimits in turn to work a bit more like the .bdrv_opt_mem_align() callback of the RFC; allows updating the BlockLimits later when the chain changes or bdrv_reopen() toggles O_DIRECT - Fixed a typo in a commit message [Eric] Kevin Wolf (20): block: Move initialisation of BlockLimits to bdrv_refresh_limits() block: Inherit opt_transfer_length block: Update BlockLimits when they might have changed qemu_memalign: Allow small alignments block: Detect unaligned length in bdrv_qiov_is_aligned() block: Don't use guest sector size for qemu_blockalign() block: Introduce bdrv_aligned_preadv() block: Introduce bdrv_co_do_preadv() block: Introduce bdrv_aligned_pwritev() block: write: Handle COR dependency after I/O throttling block: Introduce bdrv_co_do_pwritev() block: Switch BdrvTrackedRequest to byte granularity block: Allow waiting for overlapping requests between begin/end block: Make zero-after-EOF work with larger alignment block: Generalise and optimise COR serialisation block: Make overlap range for serialisation dynamic block: Align requests in bdrv_co_do_pwritev() block: Change coroutine wrapper to byte granularity block: Make bdrv_pread() a bdrv_prwv_co() wrapper block: Make bdrv_pwrite() a bdrv_prwv_co() wrapper Paolo Bonzini (2): block: rename buffer_alignment to guest_block_size raw: Probe required direct I/O alignment block.c | 602 +++++++++++++++++++++++++++++++--------------- block/backup.c | 7 +- block/iscsi.c | 87 ++++--- block/qcow2.c | 11 +- block/qed.c | 11 +- block/raw-posix.c | 102 ++++++-- block/raw-win32.c | 41 ++++ block/stream.c | 2 + block/vmdk.c | 22 +- hw/block/virtio-blk.c | 2 +- hw/ide/core.c | 2 +- hw/scsi/scsi-disk.c | 2 +- hw/scsi/scsi-generic.c | 2 +- include/block/block.h | 6 +- include/block/block_int.h | 25 +- util/oslib-posix.c | 5 + 16 files changed, 666 insertions(+), 263 deletions(-) -- 1.8.1.4