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[/] [or1k/] [trunk/] [uclinux/] [uClinux-2.0.x/] [fs/] [xiafs/] [file.c] - Blame information for rev 1765

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Line No. Rev Author Line
1 199 simons
/*
2
 *  linux/fs/xiafs/file.c
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 *
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 *  Copyright (C) Q. Frank Xia, 1993.
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 *
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 *  Based on Linus' minix/file.c
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 *  Copyright (C) Linus Torvalds, 1991, 1992.
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 *
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 *  This software may be redistributed per Linux Copyright.
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 */
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#include <linux/sched.h>
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#include <linux/fs.h>
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#include <linux/xia_fs.h>
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#include <linux/kernel.h>
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#include <linux/errno.h>
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#include <linux/fcntl.h>
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#include <linux/stat.h>
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#include <linux/locks.h>
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#include <linux/pagemap.h>
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#include <asm/segment.h>
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#include <asm/system.h>
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#include "xiafs_mac.h"
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#define NBUF    32
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#define MIN(a,b) (((a)<(b))?(a):(b))
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#define MAX(a,b) (((a)>(b))?(a):(b))
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static int xiafs_file_read(struct inode *, struct file *, char *, int);
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static int xiafs_file_write(struct inode *, struct file *, const char *, int);
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/*
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 * We have mostly NULL's here: the current defaults are ok for
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 * the xiafs filesystem.
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 */
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static struct file_operations xiafs_file_operations = {
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    NULL,                       /* lseek - default */
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    xiafs_file_read,            /* read */
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    xiafs_file_write,           /* write */
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    NULL,                       /* readdir - bad */
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    NULL,                       /* select - default */
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    NULL,                       /* ioctl - default */
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    generic_file_mmap,          /* mmap */
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    NULL,                       /* no special open is needed */
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    NULL,                       /* release */
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    xiafs_sync_file             /* fsync */
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};
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struct inode_operations xiafs_file_inode_operations = {
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    &xiafs_file_operations,     /* default file operations */
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    NULL,                       /* create */
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    NULL,                       /* lookup */
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    NULL,                       /* link */
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    NULL,                       /* unlink */
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    NULL,                       /* symlink */
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    NULL,                       /* mkdir */
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    NULL,                       /* rmdir */
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    NULL,                       /* mknod */
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    NULL,                       /* rename */
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    NULL,                       /* readlink */
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    NULL,                       /* follow_link */
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    generic_readpage,           /* readpage */
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    NULL,                       /* writepage */
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    xiafs_bmap,                 /* bmap */
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    xiafs_truncate,             /* truncate */
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    NULL                        /* permission */
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};
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static int
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xiafs_file_read(struct inode * inode, struct file * filp, char * buf, int count)
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{
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    int read, left, chars;
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    int zone_nr, zones, f_zones, offset;
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    int bhrequest, uptodate;
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    struct buffer_head ** bhb, ** bhe;
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    struct buffer_head * bhreq[NBUF];
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    struct buffer_head * buflist[NBUF];
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    if (!inode) {
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        printk("XIA-FS: inode = NULL (%s %d)\n", WHERE_ERR);
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        return -EINVAL;
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    }
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    if (!S_ISREG(inode->i_mode)) {
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        printk("XIA-FS: mode != regular (%s %d)\n", WHERE_ERR);
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        return -EINVAL;
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    }
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    offset = filp->f_pos;
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    left = inode->i_size - offset;
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    if (left > count)
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        left = count;
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    if (left <= 0)
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        return 0;
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    read = 0;
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    zone_nr = offset >> XIAFS_ZSIZE_BITS(inode->i_sb);
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    offset &= XIAFS_ZSIZE(inode->i_sb) -1 ;
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    f_zones =(inode->i_size+XIAFS_ZSIZE(inode->i_sb)-1)>>XIAFS_ZSIZE_BITS(inode->i_sb);
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    zones = (left+offset+XIAFS_ZSIZE(inode->i_sb)-1) >> XIAFS_ZSIZE_BITS(inode->i_sb);
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    bhb = bhe = buflist;
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    if (filp->f_reada) {
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        if(zones < read_ahead[MAJOR(inode->i_dev)] >> (1+XIAFS_ZSHIFT(inode->i_sb)))
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          zones = read_ahead[MAJOR(inode->i_dev)] >> (1+XIAFS_ZSHIFT(inode->i_sb));
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        if (zone_nr + zones > f_zones)
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            zones = f_zones - zone_nr;
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    }
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    /* We do this in a two stage process.  We first try to request
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       as many blocks as we can, then we wait for the first one to
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       complete, and then we try to wrap up as many as are actually
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       done.  This routine is rather generic, in that it can be used
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       in a filesystem by substituting the appropriate function in
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       for getblk.
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       This routine is optimized to make maximum use of the various
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       buffers and caches. */
118
 
119
    do {
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        bhrequest = 0;
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        uptodate = 1;
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        while (zones--) {
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            *bhb = xiafs_getblk(inode, zone_nr++, 0);
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            if (*bhb && !buffer_uptodate(*bhb)) {
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                uptodate = 0;
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                bhreq[bhrequest++] = *bhb;
127
            }
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129
            if (++bhb == &buflist[NBUF])
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                bhb = buflist;
131
 
132
            /* If the block we have on hand is uptodate, go ahead
133
               and complete processing. */
134
            if (uptodate)
135
                break;
136
            if (bhb == bhe)
137
                break;
138
        }
139
 
140
        /* Now request them all */
141
        if (bhrequest)
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            ll_rw_block(READ, bhrequest, bhreq);
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144
        do { /* Finish off all I/O that has actually completed */
145
            if (*bhe) {
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                wait_on_buffer(*bhe);
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                if (!buffer_uptodate(*bhe)) {   /* read error? */
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                    brelse(*bhe);
149
                    if (++bhe == &buflist[NBUF])
150
                      bhe = buflist;
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                    left = 0;
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                    break;
153
                }
154
            }
155
            if (left < XIAFS_ZSIZE(inode->i_sb) - offset)
156
                chars = left;
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            else
158
                chars = XIAFS_ZSIZE(inode->i_sb) - offset;
159
            filp->f_pos += chars;
160
            left -= chars;
161
            read += chars;
162
            if (*bhe) {
163
                memcpy_tofs(buf,offset+(*bhe)->b_data,chars);
164
                brelse(*bhe);
165
                buf += chars;
166
            } else {
167
                while (chars-->0)
168
                    put_user(0,buf++);
169
            }
170
            offset = 0;
171
            if (++bhe == &buflist[NBUF])
172
                bhe = buflist;
173
        } while (left > 0 && bhe != bhb && (!*bhe || !buffer_locked(*bhe)));
174
    } while (left > 0);
175
 
176
/* Release the read-ahead blocks */
177
    while (bhe != bhb) {
178
        brelse(*bhe);
179
        if (++bhe == &buflist[NBUF])
180
            bhe = buflist;
181
    };
182
    if (!read)
183
        return -EIO;
184
    filp->f_reada = 1;
185
    if (!IS_RDONLY (inode)) {
186
        inode->i_atime = CURRENT_TIME;
187
        inode->i_dirt = 1;
188
    }
189
    return read;
190
}
191
 
192
static int
193
xiafs_file_write(struct inode * inode, struct file * filp, const char * buf, int count)
194
{
195
    off_t pos;
196
    int written, c;
197
    struct buffer_head * bh;
198
    char * cp;
199
 
200
    if (!inode) {
201
        printk("XIA-FS: inode = NULL (%s %d)\n", WHERE_ERR);
202
        return -EINVAL;
203
    }
204
    if (!S_ISREG(inode->i_mode)) {
205
        printk("XIA-FS: mode != regular (%s %d)\n", WHERE_ERR);
206
        return -EINVAL;
207
    }
208
/*
209
 * ok, append may not work when many processes are writing at the same time
210
 * but so what. That way leads to madness anyway.
211
 */
212
    if (filp->f_flags & O_APPEND)
213
        pos = inode->i_size;
214
    else
215
        pos = filp->f_pos;
216
    written = 0;
217
    while (written < count) {
218
        bh = xiafs_getblk(inode, pos >> XIAFS_ZSIZE_BITS(inode->i_sb), 1);
219
        if (!bh) {
220
            if (!written)
221
                written = -ENOSPC;
222
            break;
223
        }
224
        c = XIAFS_ZSIZE(inode->i_sb) - (pos & (XIAFS_ZSIZE(inode->i_sb) - 1));
225
        if (c > count-written)
226
            c = count-written;
227
        if (c != XIAFS_ZSIZE(inode->i_sb) && !buffer_uptodate(bh)) {
228
            ll_rw_block(READ, 1, &bh);
229
            wait_on_buffer(bh);
230
            if (!buffer_uptodate(bh)) {
231
                brelse(bh);
232
                if (!written)
233
                    written = -EIO;
234
                break;
235
            }
236
        }
237
        cp = (pos & (XIAFS_ZSIZE(inode->i_sb)-1)) + bh->b_data;
238
        memcpy_fromfs(cp,buf,c);
239
        update_vm_cache(inode,pos,cp,c);
240
        pos += c;
241
        if (pos > inode->i_size) {
242
            inode->i_size = pos;
243
            inode->i_dirt = 1;
244
        }
245
        written += c;
246
        buf += c;
247
        mark_buffer_uptodate(bh, 1);
248
        mark_buffer_dirty(bh, 0);
249
        brelse(bh);
250
    }
251
    inode->i_mtime = inode->i_ctime = CURRENT_TIME;
252
    filp->f_pos = pos;
253
    inode->i_dirt = 1;
254
 
255
    return written;
256
}

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