From: Michal Privoznik <mprivozn@redhat.com>
Date: Fri, 1 Mar 2019 10:42:20 +0000 (+0100)
Subject: storage_backend_iscsi_direct: Simplify vol zeroing
X-Git-Tag: v5.2.0-rc1~144
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=f7b9d6f78bff158a929eb248b31c77f852c1c6f8;p=thirdparty%2Flibvirt.git

storage_backend_iscsi_direct: Simplify vol zeroing

So far we have two branches: either we zero BLOCK_PER_PACKET
(currently 128) block at once, or if we're close to the last block
then we zero out one block at the time. This is very suboptimal.
We know how many block are there left. Might as well just write
them all at once.

Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Pavel Hrdina <phrdina@redhat.com>
---

diff --git a/src/storage/storage_backend_iscsi_direct.c b/src/storage/storage_backend_iscsi_direct.c
index 6283a2836b..deb02a7173 100644
--- a/src/storage/storage_backend_iscsi_direct.c
+++ b/src/storage/storage_backend_iscsi_direct.c
@@ -638,21 +638,23 @@ virStorageBackendISCSIDirectVolWipeZero(virStorageVolDefPtr vol,
         return ret;
 
     while (lba < nb_block) {
-        if (nb_block - lba > block_size * BLOCK_PER_PACKET) {
+        const uint64_t to_write = MIN(nb_block - lba + 1, BLOCK_PER_PACKET);
 
-            if (!(task = iscsi_write16_sync(iscsi, lun, lba, data,
-                                            block_size * BLOCK_PER_PACKET,
-                                            block_size, 0, 0, 0, 0, 0)))
-                return -1;
-            scsi_free_scsi_task(task);
-            lba += BLOCK_PER_PACKET;
-        } else {
-            if (!(task = iscsi_write16_sync(iscsi, lun, lba, data, block_size,
-                                        block_size, 0, 0, 0, 0, 0)))
-                return -1;
+        task = iscsi_write16_sync(iscsi, lun, lba, data,
+                                  block_size * to_write,
+                                  block_size, 0, 0, 0, 0, 0);
+
+        if (!task ||
+            task->status != SCSI_STATUS_GOOD) {
+            virReportError(VIR_ERR_INTERNAL_ERROR,
+                           _("failed to write to LUN %d: %s"),
+                           lun, iscsi_get_error(iscsi));
             scsi_free_scsi_task(task);
-            lba++;
+            return -1;
         }
+
+        scsi_free_scsi_task(task);
+        lba += to_write;
     }
 
     return 0;