On Tue, 8 Apr 2025 19:44:47 +0800 Gao Xiang <hsiang...@linux.alibaba.com> wrote:
> I'm unsure why they aren't 2 bytes in size only in arm-linux-gnueabi. IIRC one of the arm ABI aligns structures on 32 bit boundaries. > > Reported-by: kernel test robot <l...@intel.com> > Closes: https://lore.kernel.org/r/202504051202.ds7qiknj-...@intel.com > Fixes: 61ba89b57905 ("erofs: add 48-bit block addressing on-disk support") > Fixes: efb2aef569b3 ("erofs: add encoded extent on-disk definition") > Signed-off-by: Gao Xiang <hsiang...@linux.alibaba.com> > --- > fs/erofs/erofs_fs.h | 8 ++++---- > 1 file changed, 4 insertions(+), 4 deletions(-) > > diff --git a/fs/erofs/erofs_fs.h b/fs/erofs/erofs_fs.h > index 61a5ee11f187..94bf636776b0 100644 > --- a/fs/erofs/erofs_fs.h > +++ b/fs/erofs/erofs_fs.h > @@ -56,7 +56,7 @@ struct erofs_super_block { > union { > __le16 rootnid_2b; /* nid of root directory */ > __le16 blocks_hi; /* (48BIT on) blocks count MSB */ > - } rb; > + } __packed rb; > __le64 inos; /* total valid ino # (== f_files - f_favail) */ > __le64 epoch; /* base seconds used for compact inodes */ > __le32 fixed_nsec; /* fixed nanoseconds for compact inodes */ > @@ -148,7 +148,7 @@ union erofs_inode_i_nb { > __le16 nlink; /* if EROFS_I_NLINK_1_BIT is unset */ > __le16 blocks_hi; /* total blocks count MSB */ > __le16 startblk_hi; /* starting block number MSB */ > -}; > +} __packed; That shouldn't be necessary and will kill performance on some systems. The 'packed' on the member should be enough to reduce the size. I'd add a compile assert (of some form) on the size of the structure. David > > /* 32-byte reduced form of an ondisk inode */ > struct erofs_inode_compact { > @@ -369,9 +369,9 @@ struct z_erofs_map_header { > * bit 7 : pack the whole file into packed inode > */ > __u8 h_clusterbits; > - }; > + } __packed; > __le16 h_extents_hi; /* extent count MSB */ > - }; > + } __packed; Ditto > }; > > enum {
