@@ -256,6 +256,45 @@ case "$FSTYP" in
xfs|udf|pvfs2|9p|ceph|nfs)
MAX_ATTRS=1000
;;
+ext2|ext3|ext4)
+ # For 4k blocksizes, most of the attributes have an attr_name of
+ # "attribute_NN" which is 12, and "value_NN" which is 8.
+ # But for larger block sizes, we start having extended attributes of the
+ # form "attribute_NNN" or "attribute_NNNN", and "value_NNN" and
+ # "value_NNNN", which causes the round(len(..), 4) to jump up by 4
+ # bytes. So round_up(len(attr_name, 4)) becomes 16 instead of 12, and
+ # round_up(len(value, 4)) becomes 12 instead of 8.
+ #
+ # For 64K blocksize the calculation becomes
+ # max_attrs = (block_size - 32) / (16 + 12 + 16)
+ # or
+ # max_attrs = (block_size - 32) / 44
+ #
+ # For 4K blocksize:-
+ # max_attrs = (block_size - 32) / (16 + 8 + 12)
+ # or
+ # max_attrs = (block_size - 32) / 36
+ #
+ # Note (for 4K bs) above are exact calculations for attrs of type
+ # attribute_NN with values of type value_NN.
+ # With above calculations, for 4k blocksize max_attrs becomes 112.
+ # This means we can have few attrs of type attribute_NNN with values of
+ # type value_NNN. To avoid/handle this we need to add extra 4 bytes of
+ # headroom.
+ #
+ # So for 4K, the calculations becomes:-
+ # max_attrs = (block_size - 32) / (16 + 8 + 12 + 4)
+ # or
+ # max_attrs = (block_size - 32) / 40
+ #
+ # Assume max ~1 block of attrs
+ BLOCK_SIZE=`_get_block_size $TEST_DIR`
+ if [ $BLOCK_SIZE -le 4096 ]; then
+ let MAX_ATTRS=$((($BLOCK_SIZE - 32) / (16 + 8 + 12 + 4)))
+ else
+ let MAX_ATTRS=$((($BLOCK_SIZE - 32) / (16 + 12 + 16 )))
+ fi
+ ;;
*)
# Assume max ~1 block of attrs
BLOCK_SIZE=`_get_block_size $TEST_DIR`
Test generic/020 fails for ext4 with 64K blocksize. This adds changes in common/attr for MAX_ATTRS calculations for ext2|ext3|ext4 along with comments explaining the calculations. Suggested-by: Theodore Ts'o <tytso@mit.edu> Signed-off-by: Ritesh Harjani <riteshh@linux.ibm.com> --- common/attr | 39 +++++++++++++++++++++++++++++++++++++++ 1 file changed, 39 insertions(+)