The padding at the end of struct ext4_tune_sb_params is architecture
specific and in particular is different between x86-32 and x86-64,
since the __u64 member only enforces struct alignment on the latter.
This shows up as a new warning when test-building the headers with
-Wpadded:
include/linux/ext4.h:144:1: error: padding struct size to alignment boundary with 4 bytes [-Werror=padded]
All members inside the structure are naturally aligned, so the only
difference here is the amount of padding at the end. Make the padding
explicit, to have a consistent sizeof(struct ext4_tune_sb_params) of
232 on all architectures and avoid adding compat ioctl handling for
EXT4_IOC_GET_TUNE_SB_PARAM/EXT4_IOC_SET_TUNE_SB_PARAM.
This is an ABI break on x86-32 but hopefully this can go into 6.18.y early
enough as a fixup so no actual users will be affected. Alternatively, the
kernel could handle the ioctl commands for both sizes (232 and 228 bytes)
on all architectures.
Fixes: 04a91570ac ("ext4: implemet new ioctls to set and get superblock parameters")
Signed-off-by: Arnd Bergmann <[email protected]>
Reviewed-by: Jan Kara <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Theodore Ts'o <[email protected]>
Cc: [email protected]
Implement the EXT4_IOC_GET_TUNE_SB_PARAM and
EXT4_IOC_SET_TUNE_SB_PARAM ioctls, which allow certains superblock
parameters to be set while the file system is mounted, without needing
write access to the block device.
Reviewed-by: Darrick J. Wong <[email protected]>
Reviewed-by: Jan Kara <[email protected]>
Signed-off-by: Theodore Ts'o <[email protected]>
Message-ID: <[email protected]>
Signed-off-by: Theodore Ts'o <[email protected]>
Arnd Bergmann