Re: [PATCH V2] xfstests: make 275 pass

[Liu Bo <liubo2009@cn.fujitsu.com>]

On 01/05/2012 04:54 AM, Eric Sandeen wrote:
> Ok, this is a significant rework of 275, which made too many
> assumptions about details of space usage and failed on several
> filesystems (it passed on xfs, but only by accident).
> 
> This new version tries to leave about 256k free, then tries
> a single 1M IO, and fails only if 0 bytes are written.
> 
> It also sends a lot more to $seq.full for debugging on failure
> and fixes a few other stylistic things.
> 
> Signed-off-by: Eric Sandeen <sandeen@redhat.com>
> ---
> 
> diff --git a/275 b/275
> index 214262e..8f521f8 100755
> --- a/275
> +++ b/275
> @@ -1,8 +1,8 @@
>  #! /bin/bash
>  # FS QA Test No. 275
>  #
> -# The posix write test. when write size is larger than disk free size,
> -# should write as more as possible
> +# The posix write test.  When write size is larger than disk free size,
> +# should write as much as possible until ENOSPC.
>  #
>  #-----------------------------------------------------------------------
>  # Copyright (c) 2011-2012 Fujitsu, Inc.  All Rights Reserved.
> @@ -30,13 +30,12 @@ echo "QA output created by $seq"
>  
>  here=`pwd`
>  tmp=/tmp/$$
> -status=0    # success is the default!
> +status=1    # failure is the default!
>  trap "_cleanup; exit \$status" 0 1 2 3 15
>  
>  _cleanup()
>  {
>  	cd /
> -	rm -f $SCRATCH_MNT/* $tmp.*
>  	_scratch_unmount
>  }
>  
> @@ -49,7 +48,7 @@ _supported_os IRIX Linux
>  _require_scratch
>  
>  echo "------------------------------"
> -echo "write lack test"
> +echo "write until ENOSPC test"
>  echo "------------------------------"
>  
>  rm -f $seq.full
> @@ -59,31 +58,38 @@ _scratch_mkfs_sized $((1 * 1024 * 1024 * 1024)) >>$seq.full 2>&1
>  _scratch_mount
>  
>  rm -rf $SCRATCH_MNT/*
> -cd $SCRATCH_MNT
>  
> -dd if=/dev/zero of=tmp1 bs=4K count=1 >/dev/null 2>&1
> -if [ $? -ne 0 ]
> -then
> -	echo "create file err"
> -	status=1
> -	exit
> -fi
> +dd if=/dev/zero of=$SCRATCH_MNT/tmp1 bs=256K count=1 >>$seq.full 2>&1
> +[ $? -ne 0 ] && _fail "Error creating file"
>  
> -dd if=/dev/zero of=tmp2 bs=1M >/dev/null 2>&1
> -dd if=/dev/zero of=tmp3 bs=4K >/dev/null 2>&1
> +# Attempt to completely fill fs
> +dd if=/dev/zero of=$SCRATCH_MNT/tmp2 bs=1M >>$seq.full 2>&1
>  sync
> +dd if=/dev/zero of=$SCRATCH_MNT/tmp3 bs=4K >>$seq.full 2>&1
> +sync
> +# Last effort, use O_SYNC
> +dd if=/dev/zero of=$SCRATCH_MNT/tmp4 bs=4K oflag=sync >>$seq.full 2>&1
> +# Save space usage info to the full file
> +echo "Pre rm space:" >> $seq.full
> +df $SCRATCH_MNT >>$seq.full 2>&1
>  
> -rm -f tmp1
> +# Should leave approx 256k free
> +rm -f $SCRATCH_MNT/tmp1
>  sync
> +echo "Post rm space:" >> $seq.full
> +df $SCRATCH_MNT >>$seq.full 2>&1
> +_freespace=`df -k $SCRATCH_MNT | tail -n 1 | awk '{print $4}'`
> +[ $_freespace -gt 1024 ] && _fail "could not sufficiently fill filesystem"
> +

I doubt this cause btrfs has a mixed data+meta mode, which means data and metadata can
share space, but this mode is only enabled when the filesystem size is less than 1G.

We can apply the below to avoid it:
-_scratch_mkfs_sized $((1 * 1024 * 1024 * 1024)) >>$seq.full 2>&1
+_scratch_mkfs_sized $((2 * 1024 * 1024 * 1024)) >>$seq.full 2>&1


> +# Try a write larger than available space
> +dd if=/dev/zero of=$SCRATCH_MNT/tmp1 bs=1M count=1 >>$seq.full 2>&1
> +echo "Bytes written until ENOSPC:" >>$seq.full
> +du $SCRATCH_MNT/tmp1 >>$seq.full
>  
> -dd if=/dev/zero of=tmp1 bs=8K count=1 >/dev/null 2>&1
> -_filesize=`du tmp1 | awk '{print $1}'`
> -if [ $_filesize -ne 4 ]
> -then
> -	echo "write file err"
> -	status=1
> -	exit
> -fi
> +# And at least some of it should succeed.
> +_filesize=`du $SCRATCH_MNT/tmp1 | awk '{print $1}'`
> +[ $_filesize -eq 0 ] && _fail "write file err: Partial write until enospc failed; wrote 0 bytes."
>  

And btrfs will check free space first and then decide if it should allocate blocks, so a partial write
will fail anyway.


Other parts looks good to me :)

thanks,
liubo

>  echo "done"
> +status=0
>  exit
> diff --git a/275.out b/275.out
> index 30af43c..69b9d52 100644
> --- a/275.out
> +++ b/275.out
> @@ -1,5 +1,5 @@
>  QA output created by 275
>  ------------------------------
> -write lack test
> +write until ENOSPC test
>  ------------------------------
>  done
> 
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