Hi, Dave Chinner

Thanks for suggest.

* From: Dave Chinner [mailto:[email protected]]
> Subject: Re: [PATCH 2/2] Fix warning of "Usage: _is_block_dev dev"
> 
> On Mon, Feb 16, 2015 at 02:50:40PM +0800, Zhaolei wrote:
> > From: Zhao Lei <[email protected]>
> >
> > _is_block_dev() will show above warning when "$dev" is not exist.
> > It happened when the program check $TEST_DEV with blank $SCRATCH_DEV
> > which is optional.
> >
> > Changelog v1->v2:
> >  Rewrite _is_block_dev() to make caller code simple.
> >  Suggested by: Dave Chinner <[email protected]>
> 
> You haven't implemented what I suggested.
> 
> > Signed-off-by: Zhao Lei <[email protected]>
> > ---
> >  common/rc | 63
> > ++++++++++++++++++++++++++++++++++-----------------------------
> >  1 file changed, 34 insertions(+), 29 deletions(-)
> >
> > diff --git a/common/rc b/common/rc
> > index 76522d4..c5f6953 100644
> > --- a/common/rc
> > +++ b/common/rc
> > @@ -947,12 +947,11 @@ _fs_options()
> >
> >  # returns device number if a file is a block device  #
> > -_is_block_dev()
> > +_dev_type()
> >  {
> >      if [ $# -ne 1 ]
> >      then
> > -   echo "Usage: _is_block_dev dev" 1>&2
> > -   exit 1
> > +        return
> >      fi
> >
> >      _dev=$1
> 
> This will only output something if the device is a block device.
> It's not a generic function. it still only returns a major:minor device 
> number if
> the device is a block device. Most callers do not use this value.
> 
> # Returns:
> #     -1 if no argument passed
> #     0 if filename is not a block device
> #     1 if filename is a block device.
> _is_block_dev()
> {
>       if [ $# -ne 1 ]; then
>               return -1;
>       fi
> 
>       if [ -b $1 ]; then
>               return 1;
>       fi
>       return 0;
> }
> 
Maybe better to return 0 if it is block dev,
to avoid following code in caller:
_is_block_dev "$dev"
if [ "$?" != 1 ] ...

Will send v3.

Thanks
Zhaolei

> 
> > @@ -965,6 +964,25 @@ _is_block_dev()
> >      fi
> >  }
> >
> > +_is_block_dev()
> > +{
> > +    _dev_type=`_dev_type "$1"`
> > +    if [ -z "$_dev_type" ]; then
> > +   return 1
> > +    fi
> > +
> > +    _not_same_dev_type=`_dev_type "$2"`
> > +    if [ -z "$_not_same_dev_type" ]; then
> > +   return 0
> > +    fi
> > +
> > +    if [ "$_dev_type" = "$_not_same_dev_type" ]; then
> > +   return 1
> > +    fi
> > +
> > +    return 0
> > +}
> 
> This function is testing if two devices are the same device.
> 
> # Returns:
> #     0 if the devices are not the same
> #     1 if the devices are the same.
> __same_block_dev()
> {
>       if [ $# -ne 2 ]; then
>               return 0;
>       fi
> 
>       if [ ! -b $1 -o ! -b $2 ]; then
>               return 0;
>       fi
> 
>       if [ `stat -c %t,%T $1` != `stat -c %t,%T $2` ]; then
>               return 0;
>       fi
>       return 1;
> }
> 
> > +
> >  # Do a command, log it to $seqres.full, optionally test return status
> > # and die if command fails. If called with one argument _do executes
> > the  # command, logs it, and returns its exit status. With two
> > arguments _do @@ -1095,19 +1113,14 @@ _require_scratch_nocheck()
> >             fi
> >             ;;
> >     *)
> > -            if [ -z "$SCRATCH_DEV" -o "`_is_block_dev $SCRATCH_DEV`" = "" ]
> > -            then
> > -                _notrun "this test requires a valid \$SCRATCH_DEV"
> > -            fi
> > -            if [ "`_is_block_dev $SCRATCH_DEV`" = "`_is_block_dev
> $TEST_DEV`" ]
> > -            then
> > -                _notrun "this test requires a valid \$SCRATCH_DEV"
> > -            fi
> > +           if ! _is_block_dev "$SCRATCH_DEV" "$TEST_DEV"; then
> > +               _notrun "this test requires a valid \$SCRATCH_DEV"
> > +           fi
> 
> This doesn't make sense when you read it - the two checks are logically
> separate, self documenting checks and should stay that way. i.e.  the two
> checks are "if (!_is_block_dev $SCRATCH_DEV) _notrun..." and "if
> (_same_block_dev $TEST_DEV $SCRATCH_DEV) _notrun ...."
> 
> >             if [ ! -d "$SCRATCH_MNT" ]
> >             then
> > -                _notrun "this test requires a valid \$SCRATCH_MNT"
> > +               _notrun "this test requires a valid \$SCRATCH_MNT"
> >             fi
> > -            ;;
> > +           ;;
> >      esac
> >
> >      # mounted?
> > @@ -1167,19 +1180,14 @@ _require_test()
> >             fi
> >             ;;
> >     *)
> > -            if [ -z "$TEST_DEV" -o "`_is_block_dev $TEST_DEV`" = "" ]
> > -            then
> > -                _notrun "this test requires a valid \$TEST_DEV"
> > -            fi
> > -            if [ "`_is_block_dev $SCRATCH_DEV`" = "`_is_block_dev
> $TEST_DEV`" ]
> > -            then
> > -                _notrun "this test requires a valid \$TEST_DEV"
> > -            fi
> > +           if ! _is_block_dev "$TEST_DEV" "$SCRATCH_DEV"; then
> > +               _notrun "this test requires a valid \$TEST_DEV"
> > +           fi
> 
> Same, but this time for $TEST_DEV
> 
> >             if [ ! -d "$TEST_DIR" ]
> >             then
> > -                _notrun "this test requires a valid \$TEST_DIR"
> > +               _notrun "this test requires a valid \$TEST_DIR"
> >             fi
> > -            ;;
> > +           ;;
> >      esac
> >
> >      # mounted?
> > @@ -1288,7 +1296,7 @@ _require_block_device()
> >     echo "Usage: _require_block_device <dev>" 1>&2
> >     exit 1
> >      fi
> > -    if [ "`_is_block_dev $1`" == "" ]; then
> > +    if ! _is_block_dev "$1"; then
> >     _notrun "require $1 to be valid block disk"
> 
> Please keep the code using the if [ ]; then syntax.
> >      fi
> >  }
> > @@ -2236,11 +2244,8 @@ _require_scratch_dev_pool()
> >     esac
> >
> >     for i in $SCRATCH_DEV_POOL; do
> > -           if [ "`_is_block_dev $i`" = "" ]; then
> > -                   _notrun "this test requires valid block disk $i"
> > -           fi
> > -           if [ "`_is_block_dev $i`" = "`_is_block_dev $TEST_DEV`" ]; then
> > -                   _notrun "$i is part of TEST_DEV, this test requires 
> > unique disks"
> > +           if ! _is_block_dev "$i" "$TEST_DEV"; then
> > +                   _notrun "$i is not valid valid block disk, or part of 
> > TEST_DEV, this
> test requires unique valid disks"
> 
> And that error message is too long. Seperate tests tell us exactly what the
> error is, not make us guess which of many errors it could have been.
> 
> Cheers,
> 
> Dave.
> --
> Dave Chinner
> [email protected]


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