From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:47344) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XjVxg-0001CK-4x for qemu-devel@nongnu.org; Wed, 29 Oct 2014 12:19:13 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1XjVxW-0001KZ-02 for qemu-devel@nongnu.org; Wed, 29 Oct 2014 12:19:04 -0400 Received: from mx-v6.kamp.de ([2a02:248:0:51::16]:50735 helo=mx01.kamp.de) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XjVxV-0001KB-Kw for qemu-devel@nongnu.org; Wed, 29 Oct 2014 12:18:53 -0400 Message-ID: <54511367.8010703@kamp.de> Date: Wed, 29 Oct 2014 17:18:47 +0100 From: Peter Lieven MIME-Version: 1.0 References: <1414588414-633-1-git-send-email-famz@redhat.com> <5450EC1A.9020502@redhat.com> In-Reply-To: <5450EC1A.9020502@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: Paolo Bonzini , Fam Zheng , qemu-devel@nongnu.org Cc: Kevin Wolf , Stefan Hajnoczi , Ronnie Sahlberg Am 29.10.2014 um 14:31 schrieb Paolo Bonzini: > > 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); scsi_datain_unmarshall may fail. You need to check for NULL here. Peter >> + 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); >>