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-Wflex-array-member-not-at-end was introduced in GCC-14, and we are getting ready to enable it, globally. So, in order to avoid ending up with a flexible-array member in the middle of other structs, we use the `struct_group_tagged()` helper to create a new tagged `struct posix_acl_hdr`. This structure groups together all the members of the flexible `struct posix_acl` except the flexible array. As a result, the array is effectively separated from the rest of the members without modifying the memory layout of the flexible structure. We then change the type of the middle struct member currently causing trouble from `struct posix_acl` to `struct posix_acl_hdr`. We also want to ensure that when new members need to be added to the flexible structure, they are always included within the newly created tagged struct. For this, we use `static_assert()`. This ensures that the memory layout for both the flexible structure and the new tagged struct is the same after any changes. This approach avoids having to implement `struct posix_acl_hdr` as a completely separate structure, thus preventing having to maintain two independent but basically identical structures, closing the door to potential bugs in the future. We also use `container_of()` whenever we need to retrieve a pointer to the flexible structure, through which we can access the flexible-array member, if necessary. So, with these changes, fix the following warning: fs/nfs_common/nfsacl.c:45:26: warning: structure containing a flexible array member is not at the end of another structure [-Wflex-array-member-not-at-end] Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org> Acked-by: Anna Schumaker <anna.schumaker@oracle.com> Acked-by: Jeff Layton <jlayton@kernel.org> Signed-off-by: Chuck Lever <chuck.lever@oracle.com>