On 2025/11/17 13:32, Heming Zhao wrote:
> On Tue, Nov 11, 2025 at 12:01:19PM +0900, Gustavo A. R. Silva wrote:
>> -Wflex-array-member-not-at-end was introduced in GCC-14, and we are
>> getting ready to enable it, globally.
>>
>> Use the new TRAILING_OVERLAP() helper to fix the following warning:
>>
>> fs/ocfs2/xattr.c:52:41: warning: structure containing a flexible array
>> member is not at the end of another structure
>> [-Wflex-array-member-not-at-end]
>>
>> This helper creates a union between a flexible-array member (FAM) and a
>> set of MEMBERS that would otherwise follow it.
>>
>> This overlays the trailing MEMBER struct ocfs2_extent_rec er; onto the
>> FAM struct ocfs2_xattr_value_root::xr_list.l_recs[], while keeping the
>> FAM and the start of MEMBER aligned.
>>
>> The static_assert() ensures this alignment remains, and it's
>> intentionally placed inmediately after the related structure --no
>> blank line in between.
>>
>> Signed-off-by: Gustavo A. R. Silva <[email protected]>
>
> LGTM.
> Reviewed-by: Heming Zhao <[email protected]>
>
Acked-by: Joseph Qi <[email protected]>
>> ---
>> fs/ocfs2/xattr.c | 8 ++++++--
>> 1 file changed, 6 insertions(+), 2 deletions(-)
>>
>> diff --git a/fs/ocfs2/xattr.c b/fs/ocfs2/xattr.c
>> index d70a20d29e3e..09069defd7e1 100644
>> --- a/fs/ocfs2/xattr.c
>> +++ b/fs/ocfs2/xattr.c
>> @@ -49,9 +49,13 @@
>> #include "ocfs2_trace.h"
>>
>> struct ocfs2_xattr_def_value_root {
>> - struct ocfs2_xattr_value_root xv;
>> - struct ocfs2_extent_rec er;
>> + /* Must be last as it ends in a flexible-array member. */
>> + TRAILING_OVERLAP(struct ocfs2_xattr_value_root, xv, xr_list.l_recs,
>> + struct ocfs2_extent_rec er;
>> + );
>> };
>> +static_assert(offsetof(struct ocfs2_xattr_def_value_root,
>> xv.xr_list.l_recs) ==
>> + offsetof(struct ocfs2_xattr_def_value_root, er));
>>
>> struct ocfs2_xattr_bucket {
>> /* The inode these xattrs are associated with */
>> --
>> 2.43.0
>>
>>
