qemu-devel.nongnu.org archive mirror
 help / color / mirror / Atom feed
* [Qemu-devel] [PATCH 1/1] mirror: do not increase offset during initial zero_or_discard phase
@ 2017-02-03 15:06 Denis V. Lunev
  2017-02-03 15:08 ` [Qemu-devel] [PATCH 1/1] mirror: do not increase offset during initial zero_or_discard phase - pls consider this as V3 patch Denis V. Lunev
  0 siblings, 1 reply; 6+ messages in thread
From: Denis V. Lunev @ 2017-02-03 15:06 UTC (permalink / raw)
  To: qemu-devel
  Cc: Anton Nefedov, Denis V . Lunev, Jeff Cody, Kevin Wolf, Max Reitz

From: Anton Nefedov <anton.nefedov@virtuozzo.com>

If explicit zeroing out before mirroring is required for the target image,
it moves the block job offset counter to EOF, then offset and len counters
count the image size twice. There is no harm but stats are confusing,
specifically the progress of the operation is always reported as 99% by
management tools.

The patch skips offset increase for the first "technical" pass over the
image. This should not cause any further harm.

Signed-off-by: Anton Nefedov <anton.nefedov@virtuozzo.com>
Signed-off-by: Denis V. Lunev <den@openvz.org>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
CC: Jeff Cody <jcody@redhat.com>
CC: Kevin Wolf <kwolf@redhat.com>
CC: Max Reitz <mreitz@redhat.com>
---
 block/mirror.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/block/mirror.c b/block/mirror.c
index 301ba92..688bc91 100644
--- a/block/mirror.c
+++ b/block/mirror.c
@@ -69,6 +69,7 @@ typedef struct MirrorBlockJob {
     bool waiting_for_io;
     int target_cluster_sectors;
     int max_iov;
+    bool init_pass;
 } MirrorBlockJob;
 
 typedef struct MirrorOp {
@@ -117,7 +118,9 @@ static void mirror_iteration_done(MirrorOp *op, int ret)
         if (s->cow_bitmap) {
             bitmap_set(s->cow_bitmap, chunk_num, nb_chunks);
         }
-        s->common.offset += (uint64_t)op->nb_sectors * BDRV_SECTOR_SIZE;
+        if (!s->init_pass) {
+            s->common.offset += (uint64_t)op->nb_sectors * BDRV_SECTOR_SIZE;
+        }
     }
 
     qemu_iovec_destroy(&op->qiov);
@@ -566,6 +569,7 @@ static int coroutine_fn mirror_dirty_init(MirrorBlockJob *s)
             return 0;
         }
 
+        s->init_pass = true;
         for (sector_num = 0; sector_num < end; ) {
             int nb_sectors = MIN(end - sector_num,
                 QEMU_ALIGN_DOWN(INT_MAX, s->granularity) >> BDRV_SECTOR_BITS);
@@ -573,6 +577,7 @@ static int coroutine_fn mirror_dirty_init(MirrorBlockJob *s)
             mirror_throttle(s);
 
             if (block_job_is_cancelled(&s->common)) {
+                s->init_pass = false;
                 return 0;
             }
 
@@ -587,6 +592,7 @@ static int coroutine_fn mirror_dirty_init(MirrorBlockJob *s)
         }
 
         mirror_wait_for_all_io(s);
+        s->init_pass = false;
     }
 
     /* First part, loop on the sectors and initialize the dirty bitmap.  */
-- 
2.7.4

^ permalink raw reply related	[flat|nested] 6+ messages in thread
end of thread, other threads:[~2017-02-13 22:19 UTC | newest]

Thread overview: 6+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2017-02-03 15:06 [Qemu-devel] [PATCH 1/1] mirror: do not increase offset during initial zero_or_discard phase Denis V. Lunev
2017-02-03 15:08 ` [Qemu-devel] [PATCH 1/1] mirror: do not increase offset during initial zero_or_discard phase - pls consider this as V3 patch Denis V. Lunev
2017-02-13  7:10   ` Denis V. Lunev
2017-02-13 17:16     ` Max Reitz
2017-02-13 19:13       ` Jeff Cody
2017-02-13 19:45         ` Denis V. Lunev

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).