The io_pattern style functions have the following loop:
  for i in `seq 1 $count`; do
      echo ... $(( start + i * step )) ...
  done
Offsets are 1-based so start=1024, step=512, count=4 yields:
1536, 2048, 2560, 3072
Normally we expect:
1024, 1536, 2048, 2560
Most tests ignore this detail, which means that they perform I/O to a
slightly different range than expected by the test author.
Later on things got less innocent and tests started trying to compensate
for the 1-based indexing.  This included negative start values in test
024 and my own attempt with count-1 in test 028!
The end result is that tests that use io_pattern are hard to reason
about and don't work the way you'd expect.  It's time to clean this mess
up.
This patch switches io_pattern to 0-based offsets.  This requires
adjusting the golden outputs since I/O ranges are now shifted and output
differs.
Verifying these output diffs is easy, however.  Each diff hunk moves one
I/O from beyond the end of the pattern range to the beginning.
Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
		
	
		
			
				
	
	
		
			126 lines
		
	
	
		
			4.2 KiB
		
	
	
	
		
			Bash
		
	
	
		
			Executable File
		
	
	
	
	
			
		
		
	
	
			126 lines
		
	
	
		
			4.2 KiB
		
	
	
	
		
			Bash
		
	
	
		
			Executable File
		
	
	
	
	
| #!/bin/bash
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| #
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| # Rebasing COW images
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| #
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| # Copyright (C) 2009 Red Hat, Inc.
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| #
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| # This program is free software; you can redistribute it and/or modify
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| # it under the terms of the GNU General Public License as published by
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| # the Free Software Foundation; either version 2 of the License, or
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| # (at your option) any later version.
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| #
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| # This program is distributed in the hope that it will be useful,
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| # but WITHOUT ANY WARRANTY; without even the implied warranty of
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| # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
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| # GNU General Public License for more details.
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| #
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| # You should have received a copy of the GNU General Public License
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| # along with this program.  If not, see <http://www.gnu.org/licenses/>.
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| #
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| 
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| # creator
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| owner=kwolf@redhat.com
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| 
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| seq=`basename $0`
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| echo "QA output created by $seq"
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| 
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| here=`pwd`
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| tmp=/tmp/$$
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| status=1	# failure is the default!
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| 
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| _cleanup()
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| {
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| 	_cleanup_test_img
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| 	rm -f $TEST_DIR/t.$IMGFMT.base_old
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| 	rm -f $TEST_DIR/t.$IMGFMT.base_new
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| }
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| trap "_cleanup; exit \$status" 0 1 2 3 15
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| 
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| # get standard environment, filters and checks
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| . ./common.rc
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| . ./common.filter
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| . ./common.pattern
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| 
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| # Currently only qcow2 and qed support rebasing
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| _supported_fmt qcow2 qed
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| _supported_proto generic
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| _supported_os Linux
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| 
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| CLUSTER_SIZE=65536
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| 
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| # Cluster allocations to be tested:
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| #
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| # Backing (old) 11  --  11  --  11  --  11  --
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| # Backing (new) 22  22  --  --  22  22  --  --
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| # COW image     33  33  33  33  --  --  --  --
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| #
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| # The pattern is written twice to have both an alloc -> non-alloc and a
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| # non-alloc -> alloc transition in the COW image.
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| 
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| echo "Creating backing file"
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| echo
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| 
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| _make_test_img 1G
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| io_pattern writev 0 $CLUSTER_SIZE $((2 * CLUSTER_SIZE)) 8 0x11
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| mv $TEST_IMG $TEST_IMG.base_old
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| 
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| echo "Creating new backing file"
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| echo
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| 
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| _make_test_img 1G
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| io_pattern writev 0 $((2 * CLUSTER_SIZE)) $((4 * CLUSTER_SIZE)) 4 0x22
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| mv $TEST_IMG $TEST_IMG.base_new
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| 
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| echo "Creating COW image"
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| echo
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| 
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| _make_test_img -b $TEST_IMG.base_old 1G
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| io_pattern writev 0 $((4 * CLUSTER_SIZE)) 0 1 0x33
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| io_pattern writev $((8 * CLUSTER_SIZE)) $((4 * CLUSTER_SIZE)) 0 1 0x33
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| 
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| echo "Read before the rebase to make sure everything is set up correctly"
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| echo
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| io_pattern readv $((0 * CLUSTER_SIZE)) $CLUSTER_SIZE 0 1 0x33
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| io_pattern readv $((1 * CLUSTER_SIZE)) $CLUSTER_SIZE 0 1 0x33
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| io_pattern readv $((2 * CLUSTER_SIZE)) $CLUSTER_SIZE 0 1 0x33
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| io_pattern readv $((3 * CLUSTER_SIZE)) $CLUSTER_SIZE 0 1 0x33
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| io_pattern readv $((4 * CLUSTER_SIZE)) $CLUSTER_SIZE 0 1 0x11
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| io_pattern readv $((5 * CLUSTER_SIZE)) $CLUSTER_SIZE 0 1 0x00
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| io_pattern readv $((6 * CLUSTER_SIZE)) $CLUSTER_SIZE 0 1 0x11
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| io_pattern readv $((7 * CLUSTER_SIZE)) $CLUSTER_SIZE 0 1 0x00
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| io_pattern readv $((8 * CLUSTER_SIZE)) $CLUSTER_SIZE 0 1 0x33
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| io_pattern readv $((9 * CLUSTER_SIZE)) $CLUSTER_SIZE 0 1 0x33
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| io_pattern readv $((10 * CLUSTER_SIZE)) $CLUSTER_SIZE 0 1 0x33
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| io_pattern readv $((11 * CLUSTER_SIZE)) $CLUSTER_SIZE 0 1 0x33
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| io_pattern readv $((12 * CLUSTER_SIZE)) $CLUSTER_SIZE 0 1 0x11
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| io_pattern readv $((13 * CLUSTER_SIZE)) $CLUSTER_SIZE 0 1 0x00
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| io_pattern readv $((14 * CLUSTER_SIZE)) $CLUSTER_SIZE 0 1 0x11
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| io_pattern readv $((15 * CLUSTER_SIZE)) $CLUSTER_SIZE 0 1 0x00
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| 
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| echo
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| echo Rebase and test again
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| echo
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| $QEMU_IMG rebase -b $TEST_IMG.base_new $TEST_IMG
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| io_pattern readv $((0 * CLUSTER_SIZE)) $CLUSTER_SIZE 0 1 0x33
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| io_pattern readv $((1 * CLUSTER_SIZE)) $CLUSTER_SIZE 0 1 0x33
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| io_pattern readv $((2 * CLUSTER_SIZE)) $CLUSTER_SIZE 0 1 0x33
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| io_pattern readv $((3 * CLUSTER_SIZE)) $CLUSTER_SIZE 0 1 0x33
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| io_pattern readv $((4 * CLUSTER_SIZE)) $CLUSTER_SIZE 0 1 0x11
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| io_pattern readv $((5 * CLUSTER_SIZE)) $CLUSTER_SIZE 0 1 0x00
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| io_pattern readv $((6 * CLUSTER_SIZE)) $CLUSTER_SIZE 0 1 0x11
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| io_pattern readv $((7 * CLUSTER_SIZE)) $CLUSTER_SIZE 0 1 0x00
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| io_pattern readv $((8 * CLUSTER_SIZE)) $CLUSTER_SIZE 0 1 0x33
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| io_pattern readv $((9 * CLUSTER_SIZE)) $CLUSTER_SIZE 0 1 0x33
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| io_pattern readv $((10 * CLUSTER_SIZE)) $CLUSTER_SIZE 0 1 0x33
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| io_pattern readv $((11 * CLUSTER_SIZE)) $CLUSTER_SIZE 0 1 0x33
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| io_pattern readv $((12 * CLUSTER_SIZE)) $CLUSTER_SIZE 0 1 0x11
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| io_pattern readv $((13 * CLUSTER_SIZE)) $CLUSTER_SIZE 0 1 0x00
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| io_pattern readv $((14 * CLUSTER_SIZE)) $CLUSTER_SIZE 0 1 0x11
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| io_pattern readv $((15 * CLUSTER_SIZE)) $CLUSTER_SIZE 0 1 0x00
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| 
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| 
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| # success, all done
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| echo "*** done"
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| rm -f $seq.full
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| status=0
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