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Re: [Qemu-devel] [PATCH v2 20/20] scsi-disk: correctly implement WRITE S
From: |
Stefan Hajnoczi |
Subject: |
Re: [Qemu-devel] [PATCH v2 20/20] scsi-disk: correctly implement WRITE SAME |
Date: |
Wed, 20 Nov 2013 15:18:23 +0100 |
User-agent: |
Mutt/1.5.21 (2010-09-15) |
On Tue, Nov 19, 2013 at 06:07:43PM +0100, Paolo Bonzini wrote:
> +static void scsi_disk_emulate_write_same(SCSIDiskReq *r, uint8_t *inbuf)
> +{
> + SCSIRequest *req = &r->req;
> + SCSIDiskState *s = DO_UPCAST(SCSIDiskState, qdev, req->dev);
> + uint32_t nb_sectors = scsi_data_cdb_length(r->req.cmd.buf);
> + WriteSameCBData *data;
> + uint8_t *buf;
> + int i;
> +
> + /* Fail if PBDATA=1 or LBDATA=1 or ANCHOR=1. */
> + if (nb_sectors == 0 || (req->cmd.buf[1] & 0x16)) {
> + scsi_check_condition(r, SENSE_CODE(INVALID_FIELD));
> + return;
> + }
> +
> + if (bdrv_is_read_only(s->qdev.conf.bs)) {
> + scsi_check_condition(r, SENSE_CODE(WRITE_PROTECTED));
> + return;
> + }
> + if (!check_lba_range(s, r->req.cmd.lba, nb_sectors)) {
> + scsi_check_condition(r, SENSE_CODE(LBA_OUT_OF_RANGE));
> + return;
> + }
> +
> + if (buffer_is_zero(inbuf, s->qdev.blocksize)) {
Where is inbuf's size checked? It must be s->qdev.blocksize for this
code to be correct.
> + int flags = (req->cmd.buf[1] & 0x8) ? BDRV_REQ_MAY_UNMAP : 0;
> +
> + /* The request is used as the AIO opaque value, so add a ref. */
> + scsi_req_ref(&r->req);
> + bdrv_acct_start(s->qdev.conf.bs, &r->acct, nb_sectors *
> s->qdev.blocksize,
> + BDRV_ACCT_WRITE);
> + r->req.aiocb = bdrv_aio_write_zeroes(s->qdev.conf.bs,
> + r->req.cmd.lba *
> (s->qdev.blocksize / 512),
> + nb_sectors * (s->qdev.blocksize
> / 512),
> + flags, scsi_aio_complete, r);
> + return;
> + }
> +
> + data = g_new0(WriteSameCBData, 1);
> + data->r = r;
> + data->sector = r->req.cmd.lba * (s->qdev.blocksize / 512);
> + data->nb_sectors = nb_sectors * (s->qdev.blocksize / 512);
> + data->iov.iov_len = MIN(data->nb_sectors * 512, SCSI_WRITE_SAME_MAX);
> + data->iov.iov_base = buf = g_malloc(data->iov.iov_len);
qemu_blockalign() so the buffer is aligned for O_DIRECT.
- [Qemu-devel] [PATCH v2 14/20] raw-posix: implement write_zeroes with MAY_UNMAP for files, (continued)
- [Qemu-devel] [PATCH v2 14/20] raw-posix: implement write_zeroes with MAY_UNMAP for files, Paolo Bonzini, 2013/11/19
- [Qemu-devel] [PATCH v2 15/20] raw-posix: implement write_zeroes with MAY_UNMAP for block devices, Paolo Bonzini, 2013/11/19
- [Qemu-devel] [PATCH v2 16/20] raw-posix: add support for write_zeroes on XFS and block devices, Paolo Bonzini, 2013/11/19
- [Qemu-devel] [PATCH v2 17/20] qemu-iotests: 033 is fast, Paolo Bonzini, 2013/11/19
- [Qemu-devel] [PATCH v2 18/20] scsi-disk: catch write protection errors in UNMAP, Paolo Bonzini, 2013/11/19
- [Qemu-devel] [PATCH v2 19/20] scsi-disk: reject ANCHOR=1 for UNMAP and WRITE SAME commands, Paolo Bonzini, 2013/11/19
- [Qemu-devel] [PATCH v2 20/20] scsi-disk: correctly implement WRITE SAME, Paolo Bonzini, 2013/11/19