On Tue, Sep 20, 2022 at 09:35:13AM +0200, Pavel Reichl wrote:
> Helper that creates files of specified size using falloc if supported,
> otherwise pwrite is used.
>
> Signed-off-by: Pavel Reichl <preichl@xxxxxxxxxx>
> ---
> common/rc | 13 +++++++++++++
> tests/generic/694 | 2 +-
> 2 files changed, 14 insertions(+), 1 deletion(-)
>
> diff --git a/common/rc b/common/rc
> index a25cbcd0..77866582 100644
> --- a/common/rc
> +++ b/common/rc
> @@ -4925,6 +4925,19 @@ hexdump()
> _fail "Use _hexdump(), please!"
> }
>
> +# Helper to write a file containing specified number of bytes using
> +# falloc if supported, otherwise use pwrite
> +_create_sizedfile()
> +{
> + length=$1
> + file=$2
> +
> + $XFS_IO_PROG -F -fc "falloc 0 $length" $file 2>&1 | grep -q "Operation not supported"
> + if [ $? -eq 0 ]; then
> + $XFS_IO_PROG -F -fc "pwrite -W 0 $length" $file >/dev/null
> + fi
> +}
I think about it more, above code might ignore a failed falloc, if it's not failed
by "Operation not supported" but really fails, this function won't print or return
any valid things.
So how about we write it like below (for reference only):
# Try to create a file which inode->i_blocks = $length (maybe a little bigger
# than expect)
_create_file_sized()
{
local length=$1
local file=$2
local tmp=`mktemp -u`
local ret=0
$XFS_IO_PROG -ft -c "falloc 0 $length" $file >$tmp.out 2>&1
ret=$?
if (grep -Eq "Operation not supported|command .* not found" $tmp.out);then
# fallocate isn't supported, fallback to general buffer write
$XFS_IO_PROG -ft -c "pwrite 0 $length" $file >$tmp.out 2>&1
ret=$?
fi
[ $ret -ne 0 ] && cat $tmp.out
rm -f $tmp.out
return $ret
}
Even though, I think this function might still not good, feel free to tell me if
anyone has better idea/suggestion about how to get a file with specified
inode->i_blocks.
Thanks,
Zorro
> +
> init_rc
>
> ################################################################################
> diff --git a/tests/generic/694 b/tests/generic/694
> index dfd988df..64c3dd9a 100755
> --- a/tests/generic/694
> +++ b/tests/generic/694
> @@ -30,7 +30,7 @@ junk_dir=$TEST_DIR/$seq
> junk_file=$junk_dir/junk
> mkdir -p $junk_dir
>
> -$XFS_IO_PROG -f -c "pwrite -W 0 4G" $junk_file > /dev/null
> +_create_sizedfile 4G $junk_file
>
> iblocks=`stat -c '%b' $junk_file`
>
> --
> 2.37.3
>
