75 lines
		
	
	
		
			3.0 KiB
		
	
	
	
		
			Diff
		
	
	
	
	
	
			
		
		
	
	
			75 lines
		
	
	
		
			3.0 KiB
		
	
	
	
		
			Diff
		
	
	
	
	
	
| From c2d0ba193251782ce258dff254b00848bfc3de5a Mon Sep 17 00:00:00 2001
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| From: John Snow <jsnow@redhat.com>
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| Date: Wed, 18 Jul 2018 22:54:43 +0200
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| Subject: [PATCH 225/268] dirty-bitmap: fix double lock on bitmap enabling
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| 
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| RH-Author: John Snow <jsnow@redhat.com>
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| Message-id: <20180718225511.14878-8-jsnow@redhat.com>
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| Patchwork-id: 81403
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| O-Subject: [RHEL-7.6 qemu-kvm-rhev PATCH 07/35] dirty-bitmap: fix double lock on bitmap enabling
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| Bugzilla: 1207657
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| RH-Acked-by: Eric Blake <eblake@redhat.com>
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| RH-Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
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| RH-Acked-by: Fam Zheng <famz@redhat.com>
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| 
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| From: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
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| 
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| Bitmap lock/unlock were added to bdrv_enable_dirty_bitmap in
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| 8b1402ce80d, but some places were not updated correspondingly, which
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| leads to trying to take this lock twice, which is dead-lock. Fix this.
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| 
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| Actually, iotest 199 (about dirty bitmap postcopy migration) is broken
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| now, and this fixes it.
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| 
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| Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
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| Message-id: 20180625165745.25259-3-vsementsov@virtuozzo.com
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| Signed-off-by: John Snow <jsnow@redhat.com>
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| (cherry picked from commit 58f72b965e9e1820d246329461216c4d13140122)
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| Signed-off-by: John Snow <jsnow@redhat.com>
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| Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>
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| ---
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|  block/dirty-bitmap.c           | 3 ++-
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|  migration/block-dirty-bitmap.c | 4 ++--
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|  2 files changed, 4 insertions(+), 3 deletions(-)
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| 
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| diff --git a/block/dirty-bitmap.c b/block/dirty-bitmap.c
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| index 4d6ae8b..f580c1a 100644
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| --- a/block/dirty-bitmap.c
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| +++ b/block/dirty-bitmap.c
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| @@ -259,8 +259,9 @@ void bdrv_enable_dirty_bitmap_locked(BdrvDirtyBitmap *bitmap)
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|  /* Called with BQL taken. */
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|  void bdrv_dirty_bitmap_enable_successor(BdrvDirtyBitmap *bitmap)
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|  {
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| +    assert(bitmap->mutex == bitmap->successor->mutex);
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|      qemu_mutex_lock(bitmap->mutex);
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| -    bdrv_enable_dirty_bitmap(bitmap->successor);
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| +    bdrv_enable_dirty_bitmap_locked(bitmap->successor);
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|      qemu_mutex_unlock(bitmap->mutex);
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|  }
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|  
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| diff --git a/migration/block-dirty-bitmap.c b/migration/block-dirty-bitmap.c
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| index dd04f10..abba0b6 100644
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| --- a/migration/block-dirty-bitmap.c
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| +++ b/migration/block-dirty-bitmap.c
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| @@ -511,7 +511,7 @@ void dirty_bitmap_mig_before_vm_start(void)
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|          DirtyBitmapLoadBitmapState *b = item->data;
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|  
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|          if (b->migrated) {
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| -            bdrv_enable_dirty_bitmap(b->bitmap);
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| +            bdrv_enable_dirty_bitmap_locked(b->bitmap);
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|          } else {
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|              bdrv_dirty_bitmap_enable_successor(b->bitmap);
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|          }
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| @@ -547,7 +547,7 @@ static void dirty_bitmap_load_complete(QEMUFile *f, DirtyBitmapLoadState *s)
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|          if (enabled_bitmaps == NULL) {
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|              /* in postcopy */
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|              bdrv_reclaim_dirty_bitmap_locked(s->bs, s->bitmap, &error_abort);
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| -            bdrv_enable_dirty_bitmap(s->bitmap);
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| +            bdrv_enable_dirty_bitmap_locked(s->bitmap);
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|          } else {
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|              /* target not started, successor must be empty */
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|              int64_t count = bdrv_get_dirty_count(s->bitmap);
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| -- 
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| 1.8.3.1
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| 
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