inode.h

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/* Inode table.  This table holds inodes that are currently in use.  In some
 * cases they have been opened by an open() or creat() system call, in other
 * cases the file system itself needs the inode for one reason or another,
 * such as to search a directory for a path name.
 * The first part of the struct holds fields that are present on the
 * disk; the second part holds fields not present on the disk.
 * The disk inode part is also declared in "type.h" as 'd1_inode' for V1
 * file systems and 'd2_inode' for V2 file systems.
 */

EXTERN struct inode {
  mode_t i_mode;                /* file type, protection, etc. */
  nlink_t i_nlinks;             /* how many links to this file */
  uid_t i_uid;                  /* user id of the file's owner */
  gid_t i_gid;                  /* group number */
  off_t i_size;                 /* current file size in bytes */
  time_t i_atime;               /* time of last access (V2 only) */
  time_t i_mtime;               /* when was file data last changed */
  time_t i_ctime;               /* when was inode itself changed (V2 only)*/
  zone_t i_zone[V2_NR_TZONES]; /* zone numbers for direct, ind, and dbl ind */
  
  /* The following items are not present on the disk. */
  dev_t i_dev;                  /* which device is the inode on */
  ino_t i_num;                  /* inode number on its (minor) device */
  int i_count;                  /* # times inode used; 0 means slot is free */
  int i_ndzones;                /* # direct zones (Vx_NR_DZONES) */
  int i_nindirs;                /* # indirect zones per indirect block */
  struct super_block *i_sp;     /* pointer to super block for inode's device */
  char i_dirt;                  /* CLEAN or DIRTY */
  char i_pipe;                  /* set to I_PIPE if pipe */
  char i_mount;                 /* this bit is set if file mounted on */
  char i_seek;                  /* set on LSEEK, cleared on READ/WRITE */
  char i_update;                /* the ATIME, CTIME, and MTIME bits are here */
} inode[NR_INODES];

#define NIL_INODE (struct inode *) 0    /* indicates absence of inode slot */

/* Field values.  Note that CLEAN and DIRTY are defined in "const.h" */
#define NO_PIPE            0    /* i_pipe is NO_PIPE if inode is not a pipe */
#define I_PIPE             1    /* i_pipe is I_PIPE if inode is a pipe */
#define NO_MOUNT           0    /* i_mount is NO_MOUNT if file not mounted on*/
#define I_MOUNT            1    /* i_mount is I_MOUNT if file mounted on */
#define NO_SEEK            0    /* i_seek = NO_SEEK if last op was not SEEK */
#define ISEEK              1    /* i_seek = ISEEK if last op was SEEK */

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