inode(4)

NAME

inode − format of an inode

SYNOPSIS

#include <sys/types.h>
#include <sys/ino.h>

DESCRIPTION

An inode for a plain file or directory in a file system has the following structure as it appears on a disk block, defined in <sys/ino.h>.

struct      dinode {
    u_short di_mode;        /* mode and type of file */
    short   di_nlink;       /* number of links to file */
    short   di_uid_lsb;     /* owner’s user id */
    short   di_gid_lsb;     /* owner’s group id */
    quad    di_size;        /* number of bytes in file */
    time_t di_atime;       /* time last accessed */
    long    di_atspare;
    time_t di_mtime;       /* time last modified */
    long    di_mtspare;
    time_t di_ctime;       /* time of last file status change */
    long    di_ctspare;
    daddr_t di_db[NDADDR]; /* disk block addresses */
    daddr_t di_ib[NIADDR]; /* indirect blocks */
    long    di_flags;       /* status */
    long    di_blocks;      /* blocks actually held */
    long    di_gen;         /* file generation number */
    short   di_uid_msb;     /* owner’s user id (top 16 bits) */
    short   di_gid_msb;     /* owner’s group id (top 16 bits) */
    long    di_spare[2];    /* reserved, currently unused */
    ino_t   di_contin;      /* continuation inode number */
};

A continuation inode contains a file’s optional access control list (ACL) entries, and has the following structure as it appears on a disk block:

struct       cinode {
    u_short ci_mode;        /* mode and type of file */
    short   ci_nlink;       /* number of links to file */
                            /* optional ACL entries */
    struct acl_entry_internal_lsb ci_acl_lsb[NOPTENTRIES];
                            /* least sig bytes of ACL uids/gids */
    struct acl_entry_internal_msb ci_acl_msb[NOPTENTRIES];
                            /* most sig bytes of ACL uids/gids */
    char    ci_spare[3];    /* reserved, currently unused */
    long    ci_ciflags;     /* status */
};

For the meaning of the defined types u_short, quad, daddr_t, and time_t, see types(5).

Continuation inodes are distinguished from other inodes by their file type. See <sys/inode.h> for the definition of these values.

See <sys/inode.h> for the definition of inode structures for special files, pipes, or FIFOs.

WARNINGS

Kernel internal structures may change from release to release without warning. Applications directly relying on these structures are not supported.

AUTHOR

AT&T, the University of California, Berkeley, and HP.

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