minix/fs/mfs/stadir.c

   1 #include "fs.h"
   2 #include <string.h>
   3 #include <sys/stat.h>
   4 #include <sys/statvfs.h>
   5 #include "inode.h"
   6 #include "super.h"
   7
   8 /*===========================================================================*
   9  *                              estimate_blocks                              *
  10  *===========================================================================*/
  11 static blkcnt_t estimate_blocks(struct inode *rip)
  12 {
  13 /* Return the number of 512-byte blocks used by this file. This includes space
  14  * used by data zones and indirect blocks (actually also zones). Reading in all
  15  * indirect blocks is too costly for a stat call, so we disregard holes and
  16  * return a conservative estimation.
  17  */
  18   blkcnt_t zones, sindirs, dindirs, nr_indirs, sq_indirs;
  19   unsigned int zone_size;
  20
  21   /* Compute the number of zones used by the file. */
  22   zone_size = rip->i_sp->s_block_size << rip->i_sp->s_log_zone_size;
  23
  24   zones = (blkcnt_t) ((rip->i_size + zone_size - 1) / zone_size);
  25
  26   /* Compute the number of indirect blocks needed for that zone count. */
  27   nr_indirs = (blkcnt_t) rip->i_nindirs;
  28   sq_indirs = nr_indirs * nr_indirs;
  29
  30   sindirs = (zones - (blkcnt_t) rip->i_ndzones + nr_indirs - 1) / nr_indirs;
  31   dindirs = (sindirs - 1 + sq_indirs - 1) / sq_indirs;
  32
  33   /* Return the number of 512-byte blocks corresponding to the number of data
  34    * zones and indirect blocks.
  35    */
  36   return (zones + sindirs + dindirs) * (blkcnt_t) (zone_size / 512);
  37 }
  38
  39
  40 /*===========================================================================*
  41  *                             fs_stat                                       *
  42  *===========================================================================*/
  43 int fs_stat(ino_t ino_nr, struct stat *statbuf)
  44 {
  45   struct inode *rip;
  46   mode_t mo;
  47   int s;
  48
  49   if ((rip = get_inode(fs_dev, ino_nr)) == NULL)
  50         return(EINVAL);
  51
  52   /* Update the atime, ctime, and mtime fields in the inode, if need be. */
  53   if (rip->i_update) update_times(rip);
  54
  55   /* Fill in the statbuf struct. */
  56   mo = rip->i_mode & I_TYPE;
  57
  58   /* true iff special */
  59   s = (mo == I_CHAR_SPECIAL || mo == I_BLOCK_SPECIAL);
  60
  61   statbuf->st_mode = (mode_t) rip->i_mode;
  62   statbuf->st_nlink = (nlink_t) rip->i_nlinks;
  63   statbuf->st_uid = rip->i_uid;
  64   statbuf->st_gid = rip->i_gid;
  65   statbuf->st_rdev = (s ? (dev_t)rip->i_zone[0] : NO_DEV);
  66   statbuf->st_size = rip->i_size;
  67   statbuf->st_atime = rip->i_atime;
  68   statbuf->st_mtime = rip->i_mtime;
  69   statbuf->st_ctime = rip->i_ctime;
  70   statbuf->st_blksize = lmfs_fs_block_size();
  71   statbuf->st_blocks = estimate_blocks(rip);
  72
  73   put_inode(rip);               /* release the inode */
  74
  75   return(OK);
  76 }
  77
  78
  79 /*===========================================================================*
  80  *                              fs_statvfs                                   *
  81  *===========================================================================*/
  82 int fs_statvfs(struct statvfs *st)
  83 {
  84   struct super_block *sp;
  85   int scale;
  86
  87   sp = &superblock;
  88
  89   scale = sp->s_log_zone_size;
  90
  91   st->f_blocks = sp->s_zones;
  92   st->f_bfree = sp->s_zones - used_zones;
  93   st->f_bavail = st->f_bfree;
  94
  95   st->f_bsize = sp->s_block_size << scale;
  96   st->f_frsize = sp->s_block_size;
  97   st->f_iosize = st->f_frsize;
  98   st->f_files = sp->s_ninodes;
  99   st->f_ffree = count_free_bits(sp, IMAP);
 100   st->f_favail = st->f_ffree;
 101   st->f_namemax = MFS_DIRSIZ;
 102
 103   return(OK);
 104 }