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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 cvf_format *cvf_formats[MAX_CVF_FORMATS]={NULL,NULL,NULL};
int cvf_format_use_count[MAX_CVF_FORMATS]={0,0,0};
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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