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-rw-r--r--block/iscsi.c42
1 files changed, 42 insertions, 0 deletions
diff --git a/block/iscsi.c b/block/iscsi.c
index 233f46285c..3485d622ec 100644
--- a/block/iscsi.c
+++ b/block/iscsi.c
@@ -1219,6 +1219,40 @@ static void iscsi_attach_aio_context(BlockDriverState *bs,
qemu_clock_get_ms(QEMU_CLOCK_REALTIME) + NOP_INTERVAL);
}
+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>
@@ -1339,6 +1373,14 @@ 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);