root/fs/minix/file.c

/* */

DEFINITIONS

1. minix_file_write

   1 /*
   2  *  linux/fs/minix/file.c
   3  *
   4  *  Copyright (C) 1991, 1992 Linus Torvalds
   5  *
   6  *  minix regular file handling primitives
   7  */
   8 
   9 #include <linux/sched.h>
  10 #include <linux/minix_fs.h>
  11 #include <linux/kernel.h>
  12 #include <linux/errno.h>
  13 #include <linux/fcntl.h>
  14 #include <linux/stat.h>
  15 #include <linux/locks.h>
  16 #include <linux/mm.h>
  17 #include <linux/pagemap.h>
  18 
  19 #include <asm/segment.h>
  20 #include <asm/system.h>
  21 
  22 #define NBUF    32
  23 
  24 #define MIN(a,b) (((a)<(b))?(a):(b))
  25 #define MAX(a,b) (((a)>(b))?(a):(b))
  26 
  27 #include <linux/fs.h>
  28 #include <linux/minix_fs.h>
  29 
  30 static int minix_file_write(struct inode *, struct file *, const char *, int);
  31 
  32 /*
  33  * We have mostly NULL's here: the current defaults are ok for
  34  * the minix filesystem.
  35  */
  36 static struct file_operations minix_file_operations = {
  37         NULL,                   /* lseek - default */
  38         generic_file_read,      /* read */
  39         minix_file_write,       /* write */
  40         NULL,                   /* readdir - bad */
  41         NULL,                   /* select - default */
  42         NULL,                   /* ioctl - default */
  43         generic_file_mmap,      /* mmap */
  44         NULL,                   /* no special open is needed */
  45         NULL,                   /* release */
  46         minix_sync_file         /* fsync */
  47 };
  48 
  49 struct inode_operations minix_file_inode_operations = {
  50         &minix_file_operations, /* default file operations */
  51         NULL,                   /* create */
  52         NULL,                   /* lookup */
  53         NULL,                   /* link */
  54         NULL,                   /* unlink */
  55         NULL,                   /* symlink */
  56         NULL,                   /* mkdir */
  57         NULL,                   /* rmdir */
  58         NULL,                   /* mknod */
  59         NULL,                   /* rename */
  60         NULL,                   /* readlink */
  61         NULL,                   /* follow_link */
  62         generic_readpage,       /* readpage */
  63         NULL,                   /* writepage */
  64         minix_bmap,             /* bmap */
  65         minix_truncate,         /* truncate */
  66         NULL                    /* permission */
  67 };
  68 
  69 static int minix_file_write(struct inode * inode, struct file * filp, const char * buf, int count)
     /*  */
  70 {
  71         off_t pos;
  72         int written,c;
  73         struct buffer_head * bh;
  74         char * p;
  75 
  76         if (!inode) {
  77                 printk("minix_file_write: inode = NULL\n");
  78                 return -EINVAL;
  79         }
  80         if (!S_ISREG(inode->i_mode)) {
  81                 printk("minix_file_write: mode = %07o\n",inode->i_mode);
  82                 return -EINVAL;
  83         }
  84         if (filp->f_flags & O_APPEND)
  85                 pos = inode->i_size;
  86         else
  87                 pos = filp->f_pos;
  88         written = 0;
  89         while (written < count) {
  90                 bh = minix_getblk(inode,pos/BLOCK_SIZE,1);
  91                 if (!bh) {
  92                         if (!written)
  93                                 written = -ENOSPC;
  94                         break;
  95                 }
  96                 c = BLOCK_SIZE - (pos % BLOCK_SIZE);
  97                 if (c > count-written)
  98                         c = count-written;
  99                 if (c != BLOCK_SIZE && !buffer_uptodate(bh)) {
 100                         ll_rw_block(READ, 1, &bh);
 101                         wait_on_buffer(bh);
 102                         if (!buffer_uptodate(bh)) {
 103                                 brelse(bh);
 104                                 if (!written)
 105                                         written = -EIO;
 106                                 break;
 107                         }
 108                 }
 109                 p = (pos % BLOCK_SIZE) + bh->b_data;
 110                 memcpy_fromfs(p,buf,c);
 111                 update_vm_cache(inode, pos, p, c);
 112                 mark_buffer_uptodate(bh, 1);
 113                 mark_buffer_dirty(bh, 0);
 114                 brelse(bh);
 115                 pos += c;
 116                 written += c;
 117                 buf += c;
 118         }
 119         if (pos > inode->i_size)
 120                 inode->i_size = pos;
 121         inode->i_mtime = inode->i_ctime = CURRENT_TIME;
 122         filp->f_pos = pos;
 123         inode->i_dirt = 1;
 124         return written;
 125 }

/* */