patch-2.1.79 linux/fs/fat/cvf.c

• Lines: 121
• Date: Thu Jan 8 14:02:41 1998
• Orig file: v2.1.78/linux/fs/fat/cvf.c
• Orig date: Wed Dec 31 16:00:00 1969

diff -u --recursive --new-file v2.1.78/linux/fs/fat/cvf.c linux/fs/fat/cvf.c
@@ -0,0 +1,120 @@
+/*
+ * CVF extensions for fat-based filesystems
+ *
+ * written 1997,1998 by Frank Gockel <gockel@sent13.uni-duisburg.de>
+ *
+ */
+ 
+#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>
+
+#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(*force)
+    { for(i=0;i<MAX_CVF_FORMATS;++i)
+      { if(cvf_formats[i])
+        { if(!strcmp(cvf_formats[i]->cvf_version_text,force))
+            return i;
+        }
+      }
+    }
+  }
+
+  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, use cvf_format=xxx option\n"); 
+  return -1;
+}