static int
xiafs_file_read(struct inode * inode, struct file * filp, char * buf, int count)
{
int read, left, chars;
int zone_nr, zones, f_zones, offset;
int bhrequest, uptodate;
struct buffer_head ** bhb, ** bhe;
struct buffer_head * bhreq[NBUF];
struct buffer_head * buflist[NBUF];
if (!inode) {
printk("XIA-FS: inode = NULL (%s %d)\n", WHERE_ERR);
return -EINVAL;
}
if (!S_ISREG(inode->i_mode)) {
printk("XIA-FS: mode != regular (%s %d)\n", WHERE_ERR);
return -EINVAL;
}
offset = filp->f_pos;
left = inode->i_size - offset;
if (left > count)
left = count;
if (left <= 0)
return 0;
read = 0;
zone_nr = offset >> XIAFS_ZSIZE_BITS(inode->i_sb);
offset &= XIAFS_ZSIZE(inode->i_sb) -1 ;
f_zones =(inode->i_size+XIAFS_ZSIZE(inode->i_sb)-1)>>XIAFS_ZSIZE_BITS(inode->i_sb);
zones = (left+offset+XIAFS_ZSIZE(inode->i_sb)-1) >> XIAFS_ZSIZE_BITS(inode->i_sb);
bhb = bhe = buflist;
if (filp->f_reada) {
zones += read_ahead[MAJOR(inode->i_dev)] >> (1+XIAFS_ZSHIFT(inode->i_sb));
if (zone_nr + zones > f_zones)
zones = f_zones - zone_nr;
}
static int
xiafs_file_read(struct inode * inode, struct file * filp, char * buf, int count)
{
int read, left, chars;
int zone_nr, zones, f_zones, offset;
int bhrequest, uptodate;
struct buffer_head ** bhb, ** bhe;
struct buffer_head * bhreq[NBUF];
struct buffer_head * buflist[NBUF];
if (!inode) {
printk("XIA-FS: inode = NULL (%s %d)\n", WHERE_ERR);
return -EINVAL;
}
if (!S_ISREG(inode->i_mode)) {
printk("XIA-FS: mode != regular (%s %d)\n", WHERE_ERR);
return -EINVAL;
}
offset = filp->f_pos;
left = inode->i_size - offset;
if (left > count)
left = count;
if (left <= 0)
return 0;
read = 0;
zone_nr = offset >> XIAFS_ZSIZE_BITS(inode->i_sb);
offset &= XIAFS_ZSIZE(inode->i_sb) -1 ;
f_zones =(inode->i_size+XIAFS_ZSIZE(inode->i_sb)-1)>>XIAFS_ZSIZE_BITS(inode->i_sb);
zones = (left+offset+XIAFS_ZSIZE(inode->i_sb)-1) >> XIAFS_ZSIZE_BITS(inode->i_sb);
bhb = bhe = buflist;
if (filp->f_reada) {
if(zones < read_ahead[MAJOR(inode->i_dev)] >> (1+XIAFS_ZSHIFT(inode->i_sb)))
zones = read_ahead[MAJOR(inode->i_dev)] >> (1+XIAFS_ZSHIFT(inode->i_sb));
if (zone_nr + zones > f_zones)
zones = f_zones - zone_nr;
}
/* We do this in a two stage process. We first try and request
as many blocks as we can, then we wait for the first one to
complete, and then we try and wrap up as many as are actually
done. This routine is rather generic, in that it can be used
in a filesystem by substituting the appropriate function in
for getblk.
This routine is optimized to make maximum use of the various
buffers and caches. */
do {
bhrequest = 0;
uptodate = 1;
while (zones--) {
*bhb = xiafs_getblk(inode, zone_nr++, 0);
if (*bhb && !(*bhb)->b_uptodate) {
uptodate = 0;
bhreq[bhrequest++] = *bhb;
}
if (++bhb == &buflist[NBUF])
bhb = buflist;
/* If the block we have on hand is uptodate, go ahead
and complete processing. */
if (uptodate)
break;
if (bhb == bhe)
break;
}
/* Now request them all */
if (bhrequest)
ll_rw_block(READ, bhrequest, bhreq);
do { /* Finish off all I/O that has actually completed */
if (*bhe) {
wait_on_buffer(*bhe);
if (!(*bhe)->b_uptodate) { /* read error? */
brelse(*bhe);
if (++bhe == &buflist[NBUF])
bhe = buflist;
left = 0;
break;
}
}
if (left < XIAFS_ZSIZE(inode->i_sb) - offset)
chars = left;
else
chars = XIAFS_ZSIZE(inode->i_sb) - offset;
filp->f_pos += chars;
left -= chars;
read += chars;
if (*bhe) {
memcpy_tofs(buf,offset+(*bhe)->b_data,chars);
brelse(*bhe);
buf += chars;
} else {
while (chars-->0)
put_fs_byte(0,buf++);
}
offset = 0;
if (++bhe == &buflist[NBUF])
bhe = buflist;
} while (left > 0 && bhe != bhb && (!*bhe || !(*bhe)->b_lock));
} while (left > 0);
/* Release the read-ahead blocks */
while (bhe != bhb) {
brelse(*bhe);
if (++bhe == &buflist[NBUF])
bhe = buflist;
};
if (!read)
return -EIO;
filp->f_reada = 1;
if (!IS_RDONLY (inode)) {
inode->i_atime = CURRENT_TIME;
inode->i_dirt = 1;
}
return read;
}
