| From 8f412efbb8bb57fde0f924a7ad084f1c536c4a0b Mon Sep 17 00:00:00 2001 |
| From: Fam Zheng <famz@redhat.com> |
| Date: Tue, 20 Jan 2015 03:42:13 +0100 |
| Subject: [PATCH 06/16] iscsi: Refuse to open as writable if the LUN is write |
| protected |
| |
| Message-id: <1421725333-27072-1-git-send-email-famz@redhat.com> |
| Patchwork-id: 63370 |
| O-Subject: [RHEL-7.2 qemu-kvm PATCH v2] iscsi: Refuse to open as writable if the LUN is write protected |
| Bugzilla: 1032412 |
| RH-Acked-by: Paolo Bonzini <pbonzini@redhat.com> |
| RH-Acked-by: Stefan Hajnoczi <stefanha@redhat.com> |
| RH-Acked-by: Kevin Wolf <kwolf@redhat.com> |
| |
| 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 <famz@redhat.com> |
| Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> |
| (cherry picked from commit c1d4096b0f033d0a52c542f0948403783c3682e9) |
| Signed-off-by: Fam Zheng <famz@redhat.com> |
| Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com> |
| |
| Conflicts: |
| block/iscsi.c |
| |
| Trivial context conflict: AioContext attach/detach functions are not |
| present in downstream. |
| |
| block/iscsi.c | 43 +++++++++++++++++++++++++++++++++++++++++++ |
| 1 file changed, 43 insertions(+) |
| |
| diff --git a/block/iscsi.c b/block/iscsi.c |
| index 4f42f29..3d61dd7 100644 |
| |
| |
| @@ -1290,6 +1290,41 @@ fail: |
| return NULL; |
| } |
| |
| + |
| +static bool iscsi_is_write_protected(IscsiLun *iscsilun) |
| +{ |
| + struct scsi_task *task; |
| + struct scsi_mode_sense *ms = NULL; |
| + bool wrprotected = false; |
| + |
| + task = iscsi_modesense6_sync(iscsilun->iscsi, iscsilun->lun, |
| + 1, SCSI_MODESENSE_PC_CURRENT, |
| + 0x3F, 0, 255); |
| + if (task == NULL) { |
| + error_report("iSCSI: Failed to send MODE_SENSE(6) command: %s", |
| + iscsi_get_error(iscsilun->iscsi)); |
| + goto out; |
| + } |
| + |
| + if (task->status != SCSI_STATUS_GOOD) { |
| + error_report("iSCSI: Failed MODE_SENSE(6), LUN assumed writable"); |
| + goto out; |
| + } |
| + ms = scsi_datain_unmarshall(task); |
| + if (!ms) { |
| + error_report("iSCSI: Failed to unmarshall MODE_SENSE(6) data: %s", |
| + iscsi_get_error(iscsilun->iscsi)); |
| + goto out; |
| + } |
| + wrprotected = ms->device_specific_parameter & 0x80; |
| + |
| +out: |
| + if (task) { |
| + scsi_free_scsi_task(task); |
| + } |
| + return wrprotected; |
| +} |
| + |
| /* |
| * We support iscsi url's on the form |
| * iscsi://[<username>%<password>@]<host>[:<port>]/<targetname>/<lun> |
| @@ -1405,6 +1440,14 @@ 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 (iscsilun->type == TYPE_DISK && (flags & BDRV_O_RDWR) && |
| + iscsi_is_write_protected(iscsilun)) { |
| + error_setg(errp, "Cannot open a write protected LUN as read-write"); |
| + ret = -EACCES; |
| + goto out; |
| + } |
| + |
| iscsi_readcapacity_sync(iscsilun, &local_err); |
| if (local_err != NULL) { |
| error_propagate(errp, local_err); |
| -- |
| 1.8.3.1 |
| |