From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:59593) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XjTLS-0004BN-61 for qemu-devel@nongnu.org; Wed, 29 Oct 2014 09:31:32 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1XjTLL-0002iJ-UR for qemu-devel@nongnu.org; Wed, 29 Oct 2014 09:31:26 -0400 Received: from mx1.redhat.com ([209.132.183.28]:44917) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XjTLL-0002iB-MF for qemu-devel@nongnu.org; Wed, 29 Oct 2014 09:31:19 -0400 Message-ID: <5450EC1A.9020502@redhat.com> Date: Wed, 29 Oct 2014 14:31:06 +0100 From: Paolo Bonzini MIME-Version: 1.0 References: <1414588414-633-1-git-send-email-famz@redhat.com> In-Reply-To: <1414588414-633-1-git-send-email-famz@redhat.com> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH] iscsi: Refuse to open as writable if the LUN is write protected List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Fam Zheng , qemu-devel@nongnu.org Cc: Kevin Wolf , Peter Lieven , Stefan Hajnoczi , Ronnie Sahlberg On 10/29/2014 02:13 PM, Fam Zheng wrote: > Before, when a write protected iSCSI target is attached as scsi-disk > with BDRV_O_RDWR, we report it as writable, while in fact all writes > will fail. > > One way to improve this is to report write protect flag as true to > guest, but a even better way is to refuse using a write protected LUN to > guest. > > Target write protect flag is checked with a mode sense query. > > Signed-off-by: Fam Zheng > --- > block/iscsi.c | 30 ++++++++++++++++++++++++++++++ > 1 file changed, 30 insertions(+) > > diff --git a/block/iscsi.c b/block/iscsi.c > index 233f462..c154928 100644 > --- a/block/iscsi.c > +++ b/block/iscsi.c > @@ -1339,6 +1339,36 @@ static int iscsi_open(BlockDriverState *bs, QDict *options, int flags, > scsi_free_scsi_task(task); > task = NULL; > > + /* Check the write protect flag of the LUN if we want to write */ > + if (flags & BDRV_O_RDWR) { > + struct scsi_mode_sense *ms; > + > + task = iscsi_modesense6_sync(iscsilun->iscsi, iscsilun->lun, > + 1, SCSI_MODESENSE_PC_CURRENT, > + 0x3F, > + 0, 255); > + > + if (task == NULL) { > + error_setg(errp, "Failed to send MODE_SENSE10 command: %s\n", This is MODE SENSE(6). Fixed and applied. Paolo > + iscsi_get_error(iscsilun->iscsi)); > + ret = -EINVAL; > + goto out; > + } > + > + if (task->status != SCSI_STATUS_GOOD) { > + error_setg(errp, "MODE_SENSE10 failed: %s\n", > + iscsi_get_error(iscsi)); > + ret = -EINVAL; > + goto out; > + } > + ms = scsi_datain_unmarshall(task); > + if (ms->device_specific_parameter & 0x80) { > + error_setg(errp, "Cannot open a write protected LUN as read-write"); > + ret = -EPERM; > + goto out; > + } > + } > + > iscsi_readcapacity_sync(iscsilun, &local_err); > if (local_err != NULL) { > error_propagate(errp, local_err); >