fs/ext2/file.c

/* */
This source file includes following definitions.
ext2_file_write
ext2_release_file
   1 /*
   2  *  linux/fs/ext2/file.c
   3  *
   4  * Copyright (C) 1992, 1993, 1994, 1995
   5  * Remy Card (card@masi.ibp.fr)
   6  * Laboratoire MASI - Institut Blaise Pascal
   7  * Universite Pierre et Marie Curie (Paris VI)
   8  *
   9  *  from
  10  *
  11  *  linux/fs/minix/file.c
  12  *
  13  *  Copyright (C) 1991, 1992  Linus Torvalds
  14  *
  15  *  ext2 fs regular file handling primitives
  16  */
  17 
  18 #include <asm/segment.h>
  19 #include <asm/system.h>
  20 
  21 #include <linux/errno.h>
  22 #include <linux/fs.h>
  23 #include <linux/ext2_fs.h>
  24 #include <linux/fcntl.h>
  25 #include <linux/sched.h>
  26 #include <linux/stat.h>
  27 #include <linux/locks.h>
  28 #include <linux/mm.h>
  29 #include <linux/pagemap.h>
  30 
  31 #define NBUF    32
  32 
  33 #define MIN(a,b) (((a)<(b))?(a):(b))
  34 #define MAX(a,b) (((a)>(b))?(a):(b))
  35 
  36 #include <linux/fs.h>
  37 #include <linux/ext2_fs.h>
  38 
  39 static int ext2_file_write (struct inode *, struct file *, const char *, int);
  40 static void ext2_release_file (struct inode *, struct file *);
  41 
  42 /*
  43  * We have mostly NULL's here: the current defaults are ok for
  44  * the ext2 filesystem.
  45  */
  46 static struct file_operations ext2_file_operations = {
  47         NULL,                   /* lseek - default */
  48         generic_file_read,      /* read */
  49         ext2_file_write,        /* write */
  50         NULL,                   /* readdir - bad */
  51         NULL,                   /* select - default */
  52         ext2_ioctl,             /* ioctl */
  53         generic_mmap,           /* mmap */
  54         NULL,                   /* no special open is needed */
  55         ext2_release_file,      /* release */
  56         ext2_sync_file,         /* fsync */
  57         NULL,                   /* fasync */
  58         NULL,                   /* check_media_change */
  59         NULL                    /* revalidate */
  60 };
  61 
  62 struct inode_operations ext2_file_inode_operations = {
  63         &ext2_file_operations,/* default file operations */
  64         NULL,                   /* create */
  65         NULL,                   /* lookup */
  66         NULL,                   /* link */
  67         NULL,                   /* unlink */
  68         NULL,                   /* symlink */
  69         NULL,                   /* mkdir */
  70         NULL,                   /* rmdir */
  71         NULL,                   /* mknod */
  72         NULL,                   /* rename */
  73         NULL,                   /* readlink */
  74         NULL,                   /* follow_link */
  75         generic_readpage,       /* readpage */
  76         NULL,                   /* writepage */
  77         ext2_bmap,              /* bmap */
  78         ext2_truncate,          /* truncate */
  79         ext2_permission,        /* permission */
  80         NULL                    /* smap */
  81 };
  82 
  83 static int ext2_file_write (struct inode * inode, struct file * filp,
     /*  */
  84                             const char * buf, int count)
  85 {
  86         const loff_t two_gb = 2147483647;
  87         loff_t pos;
  88         off_t pos2;
  89         long block;
  90         int offset;
  91         int written, c;
  92         struct buffer_head * bh, *bufferlist[NBUF];
  93         struct super_block * sb;
  94         int err;
  95         int i,buffercount,write_error;
  96 
  97         write_error = buffercount = 0;
  98         if (!inode) {
  99                 printk("ext2_file_write: inode = NULL\n");
 100                 return -EINVAL;
 101         }
 102         sb = inode->i_sb;
 103         if (sb->s_flags & MS_RDONLY)
 104                 /*
 105                  * This fs has been automatically remounted ro because of errors
 106                  */
 107                 return -ENOSPC;
 108 
 109         if (!S_ISREG(inode->i_mode)) {
 110                 ext2_warning (sb, "ext2_file_write", "mode = %07o",
 111                               inode->i_mode);
 112                 return -EINVAL;
 113         }
 114         if (filp->f_flags & O_APPEND)
 115                 pos = inode->i_size;
 116         else
 117                 pos = filp->f_pos;
 118         pos2 = (off_t) pos;
 119         /*
 120          * If a file has been opened in synchronous mode, we have to ensure
 121          * that meta-data will also be written synchronously.  Thus, we
 122          * set the i_osync field.  This field is tested by the allocation
 123          * routines.
 124          */
 125         if (filp->f_flags & O_SYNC)
 126                 inode->u.ext2_i.i_osync++;
 127         block = pos2 >> EXT2_BLOCK_SIZE_BITS(sb);
 128         offset = pos2 & (sb->s_blocksize - 1);
 129         c = sb->s_blocksize - offset;
 130         written = 0;
 131         while (count > 0) {
 132                 if (pos > two_gb) {
 133                         if (!written)
 134                                 written = -EFBIG;
 135                         break;
 136                 }
 137                 bh = ext2_getblk (inode, block, 1, &err);
 138                 if (!bh) {
 139                         if (!written)
 140                                 written = err;
 141                         break;
 142                 }
 143                 count -= c;
 144                 if (count < 0)
 145                         c += count;
 146                 if (c != sb->s_blocksize && !buffer_uptodate(bh)) {
 147                         ll_rw_block (READ, 1, &bh);
 148                         wait_on_buffer (bh);
 149                         if (!buffer_uptodate(bh)) {
 150                                 brelse (bh);
 151                                 if (!written)
 152                                         written = -EIO;
 153                                 break;
 154                         }
 155                 }
 156                 memcpy_fromfs (bh->b_data + offset, buf, c);
 157                 update_vm_cache(inode, pos, bh->b_data + offset, c);
 158                 pos2 += c;
 159                 pos += c;
 160                 written += c;
 161                 buf += c;
 162                 mark_buffer_uptodate(bh, 1);
 163                 mark_buffer_dirty(bh, 0);
 164                 if (filp->f_flags & O_SYNC)
 165                         bufferlist[buffercount++] = bh;
 166                 else
 167                         brelse(bh);
 168                 if (buffercount == NBUF){
 169                         ll_rw_block(WRITE, buffercount, bufferlist);
 170                         for(i=0; i<buffercount; i++){
 171                                 wait_on_buffer(bufferlist[i]);
 172                                 if (!buffer_uptodate(bufferlist[i]))
 173                                         write_error=1;
 174                                 brelse(bufferlist[i]);
 175                         }
 176                         buffercount=0;
 177                 }
 178                 if(write_error)
 179                         break;
 180                 block++;
 181                 offset = 0;
 182                 c = sb->s_blocksize;
 183         }
 184         if ( buffercount ){
 185                 ll_rw_block(WRITE, buffercount, bufferlist);
 186                 for(i=0; i<buffercount; i++){
 187                         wait_on_buffer(bufferlist[i]);
 188                         if (!buffer_uptodate(bufferlist[i]))
 189                                 write_error=1;
 190                         brelse(bufferlist[i]);
 191                 }
 192         }               
 193         if (pos > inode->i_size)
 194                 inode->i_size = pos;
 195         if (filp->f_flags & O_SYNC)
 196                 inode->u.ext2_i.i_osync--;
 197         inode->i_ctime = inode->i_mtime = CURRENT_TIME;
 198         filp->f_pos = pos;
 199         inode->i_dirt = 1;
 200         return written;
 201 }
 202 
 203 /*
 204  * Called when a inode is released. Note that this is different
 205  * from ext2_open: open gets called at every open, but release
 206  * gets called only when /all/ the files are closed.
 207  */
 208 static void ext2_release_file (struct inode * inode, struct file * filp)
     /*  */
 209 {
 210         if (filp->f_mode & 2)
 211                 ext2_discard_prealloc (inode);
 212 }
/* */
root/fs/ext2/file.c

DEFINITIONS
