Re: [PATCH] fix dir2 shortform structures on ARM old ABI

[Eric Sandeen <sandeen@xxxxxxxxxxx>]

Eric Sandeen wrote:

> I've helpfully provided structure layouts for the structures you mention
> in the attached files, for your diffing pleasure.  I think you'll find
> that it's not exactly as you described.

Ah hell the arm structs I attached were for oldabi.  It's what I get for
saving this fun work for late at night ;)

Attached are eabi structs; still only xfs_dir2_data_entry, xfs_dinode
and xfs_log_item seem to be affected by end-of-struct padding, of the
structures you mention.  And xfs_log_item isn't a disk structure...

which brings me back to, what specific failures do you see as a result
of end-of-struct padding on these structs?

-Eric

struct xfs_dir2_data_entry {
        __be64                     inumber;              /*     0     8 */
        __u8                       namelen;              /*     8     1 */
        __u8                       name[1];              /*     9     1 */
        __be16                     tag;                  /*    10     2 */

        /* size: 16, cachelines: 1 */
        /* padding: 4 */
        /* last cacheline: 16 bytes */
};
struct xfs_dinode {
        xfs_dinode_core_t          di_core;              /*     0    96 */
        /* --- cacheline 1 boundary (64 bytes) was 32 bytes ago --- */
        __be32                     di_next_unlinked;     /*    96     4 */
        union {
                xfs_bmdr_block_t   di_bmbt;              /*           4 */
                xfs_bmbt_rec_32_t  di_bmx[1];            /*          16 */
                xfs_dir2_sf_t      di_dir2sf;            /*          22 */
                char               di_c[1];              /*           1 */
                __be32             di_dev;               /*           4 */
                uuid_t             di_muuid;             /*          16 */
                char               di_symlink[1];        /*           1 */
        } di_u;                                          /*   100    24 */
        union {
                xfs_bmdr_block_t   di_abmbt;             /*           4 */
                xfs_bmbt_rec_32_t  di_abmx[1];           /*          16 */
                xfs_attr_shortform_t di_attrsf;          /*           8 */
        } di_a;                                          /*   124    16 */
        /* --- cacheline 2 boundary (128 bytes) was 12 bytes ago --- */

        /* size: 144, cachelines: 3 */
        /* padding: 4 */
        /* last cacheline: 16 bytes */
};
struct xfs_sb {
        __uint32_t                 sb_magicnum;          /*     0     4 */
        __uint32_t                 sb_blocksize;         /*     4     4 */
        xfs_drfsbno_t              sb_dblocks;           /*     8     8 */
        xfs_drfsbno_t              sb_rblocks;           /*    16     8 */
        xfs_drtbno_t               sb_rextents;          /*    24     8 */
        uuid_t                     sb_uuid;              /*    32    16 */
        xfs_dfsbno_t               sb_logstart;          /*    48     8 */
        xfs_ino_t                  sb_rootino;           /*    56     8 */
        /* --- cacheline 1 boundary (64 bytes) --- */
        xfs_ino_t                  sb_rbmino;            /*    64     8 */
        xfs_ino_t                  sb_rsumino;           /*    72     8 */
        xfs_agblock_t              sb_rextsize;          /*    80     4 */
        xfs_agblock_t              sb_agblocks;          /*    84     4 */
        xfs_agnumber_t             sb_agcount;           /*    88     4 */
        xfs_extlen_t               sb_rbmblocks;         /*    92     4 */
        xfs_extlen_t               sb_logblocks;         /*    96     4 */
        __uint16_t                 sb_versionnum;        /*   100     2 */
        __uint16_t                 sb_sectsize;          /*   102     2 */
        __uint16_t                 sb_inodesize;         /*   104     2 */
        __uint16_t                 sb_inopblock;         /*   106     2 */
        char                       sb_fname[12];         /*   108    12 */
        __uint8_t                  sb_blocklog;          /*   120     1 */
        __uint8_t                  sb_sectlog;           /*   121     1 */
        __uint8_t                  sb_inodelog;          /*   122     1 */
        __uint8_t                  sb_inopblog;          /*   123     1 */
        __uint8_t                  sb_agblklog;          /*   124     1 */
        __uint8_t                  sb_rextslog;          /*   125     1 */
        __uint8_t                  sb_inprogress;        /*   126     1 */
        __uint8_t                  sb_imax_pct;          /*   127     1 */
        /* --- cacheline 2 boundary (128 bytes) --- */
        __uint64_t                 sb_icount;            /*   128     8 */
        __uint64_t                 sb_ifree;             /*   136     8 */
        __uint64_t                 sb_fdblocks;          /*   144     8 */
        __uint64_t                 sb_frextents;         /*   152     8 */
        xfs_ino_t                  sb_uquotino;          /*   160     8 */
        xfs_ino_t                  sb_gquotino;          /*   168     8 */
        __uint16_t                 sb_qflags;            /*   176     2 */
        __uint8_t                  sb_flags;             /*   178     1 */
        __uint8_t                  sb_shared_vn;         /*   179     1 */
        xfs_extlen_t               sb_inoalignmt;        /*   180     4 */
        __uint32_t                 sb_unit;              /*   184     4 */
        __uint32_t                 sb_width;             /*   188     4 */
        /* --- cacheline 3 boundary (192 bytes) --- */
        __uint8_t                  sb_dirblklog;         /*   192     1 */
        __uint8_t                  sb_logsectlog;        /*   193     1 */
        __uint16_t                 sb_logsectsize;       /*   194     2 */
        __uint32_t                 sb_logsunit;          /*   196     4 */
        __uint32_t                 sb_features2;         /*   200     4 */
        __uint32_t                 sb_bad_features2;     /*   204     4 */

        /* size: 208, cachelines: 4 */
        /* last cacheline: 16 bytes */
};
struct xfs_dsb {
        __be32                     sb_magicnum;          /*     0     4 */
        __be32                     sb_blocksize;         /*     4     4 */
        __be64                     sb_dblocks;           /*     8     8 */
        __be64                     sb_rblocks;           /*    16     8 */
        __be64                     sb_rextents;          /*    24     8 */
        uuid_t                     sb_uuid;              /*    32    16 */
        __be64                     sb_logstart;          /*    48     8 */
        __be64                     sb_rootino;           /*    56     8 */
        /* --- cacheline 1 boundary (64 bytes) --- */
        __be64                     sb_rbmino;            /*    64     8 */
        __be64                     sb_rsumino;           /*    72     8 */
        __be32                     sb_rextsize;          /*    80     4 */
        __be32                     sb_agblocks;          /*    84     4 */
        __be32                     sb_agcount;           /*    88     4 */
        __be32                     sb_rbmblocks;         /*    92     4 */
        __be32                     sb_logblocks;         /*    96     4 */
        __be16                     sb_versionnum;        /*   100     2 */
        __be16                     sb_sectsize;          /*   102     2 */
        __be16                     sb_inodesize;         /*   104     2 */
        __be16                     sb_inopblock;         /*   106     2 */
        char                       sb_fname[12];         /*   108    12 */
        __u8                       sb_blocklog;          /*   120     1 */
        __u8                       sb_sectlog;           /*   121     1 */
        __u8                       sb_inodelog;          /*   122     1 */
        __u8                       sb_inopblog;          /*   123     1 */
        __u8                       sb_agblklog;          /*   124     1 */
        __u8                       sb_rextslog;          /*   125     1 */
        __u8                       sb_inprogress;        /*   126     1 */
        __u8                       sb_imax_pct;          /*   127     1 */
        /* --- cacheline 2 boundary (128 bytes) --- */
        __be64                     sb_icount;            /*   128     8 */
        __be64                     sb_ifree;             /*   136     8 */
        __be64                     sb_fdblocks;          /*   144     8 */
        __be64                     sb_frextents;         /*   152     8 */
        __be64                     sb_uquotino;          /*   160     8 */
        __be64                     sb_gquotino;          /*   168     8 */
        __be16                     sb_qflags;            /*   176     2 */
        __u8                       sb_flags;             /*   178     1 */
        __u8                       sb_shared_vn;         /*   179     1 */
        __be32                     sb_inoalignmt;        /*   180     4 */
        __be32                     sb_unit;              /*   184     4 */
        __be32                     sb_width;             /*   188     4 */
        /* --- cacheline 3 boundary (192 bytes) --- */
        __u8                       sb_dirblklog;         /*   192     1 */
        __u8                       sb_logsectlog;        /*   193     1 */
        __be16                     sb_logsectsize;       /*   194     2 */
        __be32                     sb_logsunit;          /*   196     4 */
        __be32                     sb_features2;         /*   200     4 */
        __be32                     sb_bad_features2;     /*   204     4 */

        /* size: 208, cachelines: 4 */
        /* last cacheline: 16 bytes */
};
struct xfs_log_item {
        xfs_ail_entry_t            li_ail;               /*     0     8 */
        xfs_lsn_t                  li_lsn;               /*     8     8 */
        struct xfs_log_item_desc * li_desc;              /*    16     4 */
        struct xfs_mount *         li_mountp;            /*    20     4 */
        uint                       li_type;              /*    24     4 */
        uint                       li_flags;             /*    28     4 */
        struct xfs_log_item *      li_bio_list;          /*    32     4 */
        void                       (*li_cb)(struct xfs_buf *, struct 
xfs_log_item *); /*    36     4 */
        struct xfs_item_ops *      li_ops;               /*    40     4 */

        /* size: 48, cachelines: 1 */
        /* padding: 4 */
        /* last cacheline: 48 bytes */
};