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/*
* CVF extensions for fat-based filesystems
*
* written 1997,1998 by Frank Gockel <gockel@sent13.uni-duisburg.de>
*
* please do not remove the next line, dmsdos needs it for verifying patches
* CVF-FAT-VERSION-ID: 1.2.0
*
*/
#include<linux/sched.h>
#include<linux/fs.h>
#include<linux/msdos_fs.h>
#include<linux/msdos_fs_sb.h>
#include<linux/string.h>
#include<linux/fat_cvf.h>
#include<linux/config.h>
#ifdef CONFIG_KMOD
#include<linux/kmod.h>
#endif
#define MAX_CVF_FORMATS 3
struct buffer_head *default_fat_bread(struct super_block *,int);
struct buffer_head *default_fat_getblk(struct super_block *, int);
void default_fat_brelse(struct super_block *, struct buffer_head *);
void default_fat_mark_buffer_dirty (struct super_block *, struct buffer_head *);
void default_fat_set_uptodate (struct super_block *, struct buffer_head *,int);
int default_fat_is_uptodate(struct super_block *, struct buffer_head *);
int default_fat_access(struct super_block *sb,int nr,int new_value);
void default_fat_ll_rw_block (struct super_block *sb, int opr, int nbreq,
struct buffer_head *bh[32]);
int default_fat_bmap(struct inode *inode,int block);
ssize_t default_fat_file_write(struct file *filp, const char *buf,
size_t count, loff_t *ppos);
struct cvf_format default_cvf = {
cvf_version: 0, /* version - who cares? */
cvf_version_text: "plain",
flags: 0, /* flags - who cares? */
cvf_bread: default_fat_bread,
cvf_getblk: default_fat_getblk,
cvf_brelse: default_fat_brelse,
cvf_mark_buffer_dirty: default_fat_mark_buffer_dirty,
cvf_set_uptodate: default_fat_set_uptodate,
cvf_is_uptodate: default_fat_is_uptodate,
cvf_ll_rw_block: default_fat_ll_rw_block,
fat_access: default_fat_access,
cvf_bmap: default_fat_bmap,
cvf_file_read: generic_file_read,
cvf_file_write: default_fat_file_write,
};
struct cvf_format *cvf_formats[MAX_CVF_FORMATS];
int cvf_format_use_count[MAX_CVF_FORMATS];
int register_cvf_format(struct cvf_format*cvf_format)
{ int i,j;
for(i=0;i<MAX_CVF_FORMATS;++i)
{ if(cvf_formats[i]==NULL)
{ /* free slot found, now check version */
for(j=0;j<MAX_CVF_FORMATS;++j)
{ if(cvf_formats[j])
{ if(cvf_formats[j]->cvf_version==cvf_format->cvf_version)
{ printk("register_cvf_format: version %d already registered\n",
cvf_format->cvf_version);
return -1;
}
}
}
cvf_formats[i]=cvf_format;
cvf_format_use_count[i]=0;
printk("CVF format %s (version id %d) successfully registered.\n",
cvf_format->cvf_version_text,cvf_format->cvf_version);
return 0;
}
}
printk("register_cvf_format: too many formats\n");
return -1;
}
int unregister_cvf_format(struct cvf_format*cvf_format)
{ int i;
for(i=0;i<MAX_CVF_FORMATS;++i)
{ if(cvf_formats[i])
{ if(cvf_formats[i]->cvf_version==cvf_format->cvf_version)
{ if(cvf_format_use_count[i])
{ printk("unregister_cvf_format: format %d in use, cannot remove!\n",
cvf_formats[i]->cvf_version);
return -1;
}
printk("CVF format %s (version id %d) successfully unregistered.\n",
cvf_formats[i]->cvf_version_text,cvf_formats[i]->cvf_version);
cvf_formats[i]=NULL;
return 0;
}
}
}
printk("unregister_cvf_format: format %d is not registered\n",
cvf_format->cvf_version);
return -1;
}
void dec_cvf_format_use_count_by_version(int version)
{ int i;
for(i=0;i<MAX_CVF_FORMATS;++i)
{ if(cvf_formats[i])
{ if(cvf_formats[i]->cvf_version==version)
{ --cvf_format_use_count[i];
if(cvf_format_use_count[i]<0)
{ cvf_format_use_count[i]=0;
printk(KERN_EMERG "FAT FS/CVF: This is a bug in cvf_version_use_count\n");
}
return;
}
}
}
printk("dec_cvf_format_use_count_by_version: version %d not found ???\n",
version);
}
int detect_cvf(struct super_block*sb,char*force)
{ int i;
int found=0;
int found_i=-1;
if(force)
if(strcmp(force,"autoload")==0)
{
#ifdef CONFIG_KMOD
request_module("cvf_autoload");
force=NULL;
#else
printk("cannot autoload CVF modules: kmod support is not compiled into kernel\n");
return -1;
#endif
}
#ifdef CONFIG_KMOD
if(force)
if(*force)
request_module(force);
#endif
if(force)
{ if(*force)
{ for(i=0;i<MAX_CVF_FORMATS;++i)
{ if(cvf_formats[i])
{ if(!strcmp(cvf_formats[i]->cvf_version_text,force))
return i;
}
}
printk("CVF format %s unknown (module not loaded?)\n",force);
return -1;
}
}
for(i=0;i<MAX_CVF_FORMATS;++i)
{ if(cvf_formats[i])
{ if(cvf_formats[i]->detect_cvf(sb))
{ ++found;
found_i=i;
}
}
}
if(found==1)return found_i;
if(found>1)printk("CVF detection ambiguous, please use cvf_format=xxx option\n");
return -1;
}
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