Re: [PATCH v3 1/2] generic/020: adjust max_attrval_size for ceph

[David Disseldorp <ddiss@suse.de>]

On Mon, 13 Jun 2022 12:31:41 +0100, Luís Henriques wrote:

> CephFS doesn't have a maximum xattr size.  Instead, it imposes a maximum
> size for the full set of xattrs names+values, which by default is 64K.
> 
> This patch fixes the max_attrval_size for ceph so that it is takes into
> account any already existing attrs in the file.
> 
> Signed-off-by: Luís Henriques <lhenriques@suse.de>
> ---
>  tests/generic/020 | 33 +++++++++++++++++++++++++--------
>  1 file changed, 25 insertions(+), 8 deletions(-)
> 
> diff --git a/tests/generic/020 b/tests/generic/020
> index d8648e96286e..b91bca34dcd4 100755
> --- a/tests/generic/020
> +++ b/tests/generic/020
> @@ -51,13 +51,9 @@ _attr_list()
>      fi
>  }
>  
> -# set fs-specific max_attrs and max_attrval_size values. The parameter
> -# @max_attrval_namelen is required for filesystems which take into account attr
> -# name lengths (including namespace prefix) when determining limits.
> +# set fs-specific max_attrs
>  _attr_get_max()
>  {
> -	local max_attrval_namelen="$1"
> -
>  	# set maximum total attr space based on fs type
>  	case "$FSTYP" in
>  	xfs|udf|pvfs2|9p|ceph|nfs)
> @@ -112,6 +108,16 @@ _attr_get_max()
>  		# overhead
>  		let max_attrs=$BLOCK_SIZE/40
>  	esac
> +}
> +
> +# set fs-specific max_attrval_size values. The parameter @max_attrval_namelen is
> +# required for filesystems which take into account attr name lengths (including
> +# namespace prefix) when determining limits; parameter @filename is required for
> +# filesystems that need to take into account already existing attrs.
> +_attr_get_maxval_size()
> +{
> +	local max_attrval_namelen="$1"
> +	local filename="$2"
>  
>  	# Set max attr value size in bytes based on fs type
>  	case "$FSTYP" in
> @@ -128,7 +134,7 @@ _attr_get_max()
>  	pvfs2)
>  		max_attrval_size=8192
>  		;;
> -	xfs|udf|9p|ceph)
> +	xfs|udf|9p)
>  		max_attrval_size=65536
>  		;;
>  	bcachefs)
> @@ -139,6 +145,15 @@ _attr_get_max()
>  		# the underlying filesystem, so just use the lowest value above.
>  		max_attrval_size=1024
>  		;;
> +	ceph)
> +		# CephFS does not have a maximum value for attributes.  Instead,
> +		# it imposes a maximum size for the full set of xattrs
> +		# names+values, which by default is 64K.  Compute the maximum
> +		# taking into account the already existing attributes
> +		max_attrval_size=$(getfattr --dump -e hex $filename 2>/dev/null | \
> +			awk -F "=0x" '/^user/ {len += length($1) + length($2) / 2} END {print len}')
> +		max_attrval_size=$((65536 - $max_attrval_size - $max_attrval_namelen))
> +		;;
>  	*)
>  		# Assume max ~1 block of attrs
>  		BLOCK_SIZE=`_get_block_size $TEST_DIR`
> @@ -181,8 +196,7 @@ echo "*** remove attribute"
>  _attr -r fish $testfile
>  _attr_list $testfile
>  
> -max_attrval_name="long_attr"	# add 5 for "user." prefix
> -_attr_get_max "$(( 5 + ${#max_attrval_name} ))"
> +_attr_get_max
>  
>  echo "*** add lots of attributes"
>  v=0
> @@ -226,6 +240,9 @@ done
>  _attr_list $testfile
>  
>  echo "*** really long value"
> +max_attrval_name="long_attr"	# add 5 for "user." prefix
> +_attr_get_maxval_size "$(( 5 + ${#max_attrval_name} ))" "$testfile"
> +
>  dd if=/dev/zero bs=1 count=$max_attrval_size 2>/dev/null \
>      | _attr -s "$max_attrval_name" $testfile >/dev/null
>  

Looks good.
Reviewed-by: David Disseldorp <ddiss@suse.de>