expand NEED_ALIGN for chunked items

some whackarse ARM platforms on specific glibc/gcc (new?) versions trip
SIGBUS while reading the header chunk for a split item.

the header chunk is unfortunate magic: It lives in ITEM_data() at a random
offset, is zero sized, and only exists to simplify code around finding the
orignial slab class, and linking/relinking subchunks to an item.

there's no fix to this which isn't a lot of code. I need to refactor chunked
items, and attempted to do so, but couldn't come up with something I liked
quickly enough.

This change pads the first chunk if alignment is necessary, which wastes
bytes and a little CPU, but I'm not going to worry a ton for these obscure
platforms.

this works with rebalancing because in the case of ITEM_CHUNKED header, it
treats the item size as the size of the class it resides in, and memcpy's the
item during recovery.

all other cases were changes from ITEM_data to a new ITEM_schunk() inline
function that is created when NEED_ALIGN is set, else it's equal to ITEM_data
still.

1 files changed, 1 insertions, 1 deletions

diff --git a/storage.c b/storage.c
index d0fee98..45554cf 100644
--- a/storage.c
+++ b/storage.c
@@ -62,7 +62,7 @@ static int storage_write(void *storage, const int clsid, const int item_age) {
                 // TODO: should be in items.c
                 if (it->it_flags & ITEM_CHUNKED) {
                     // Need to loop through the item and copy
-                    item_chunk *sch = (item_chunk *) ITEM_data(it);
+                    item_chunk *sch = (item_chunk *) ITEM_schunk(it);
                     int remain = orig_ntotal;
                     int copied = 0;
                     // copy original header