sys/src/cmd/ext2srv/xfile.c

   1 #include <u.h>
   2 #include <libc.h>
   3 #include <fcall.h>
   4 #include <thread.h>
   5 #include <9p.h>
   6 #include "dat.h"
   7 #include "fns.h"
   8
   9
  10 static Xfs      *xhead;
  11 static Xfile *freelist;
  12 static Lock     xlock, freelock;
  13
  14 int     client;
  15
  16 Xfs *
  17 getxfs(char *name)
  18 {
  19         int fd;
  20         Dir *dir;
  21         Xfs *xf, *fxf;
  22
  23         if(name==0 || name[0]==0)
  24                 name = deffile;
  25         if(name == 0){
  26                 errno = Enofilsys;
  27                 return 0;
  28         }
  29         fd = open(name, rdonly ? OREAD : ORDWR);
  30         if(fd < 0){
  31                 errno = Enonexist;
  32                 return 0;
  33         }
  34         if((dir = dirfstat(fd)) == 0){
  35                 errno = Eio;
  36                 close(fd);
  37                 return 0;
  38         }
  39         lock(&xlock);
  40         for(fxf=0, xf=xhead; xf; xf=xf->next){
  41                 if(xf->ref == 0){
  42                         if(fxf == 0)
  43                                 fxf = xf;
  44                         continue;
  45                 }
  46                 if(xf->qid.path != dir->qid.path || xf->qid.vers != dir->qid.vers)
  47                         continue;
  48                 if(strcmp(xf->name, name) != 0 || xf->dev < 0)
  49                         continue;
  50                 chat("incref \"%s\", dev=%d...", xf->name, xf->dev);
  51                 ++xf->ref;
  52                 unlock(&xlock);
  53                 close(fd);
  54                 free(dir);
  55                 return xf;
  56         }
  57         if(fxf==0){
  58                 fxf = malloc(sizeof(Xfs));
  59                 if(fxf==0){
  60                         unlock(&xlock);
  61                         close(fd);
  62                         free(dir);
  63                         errno = Enomem;
  64                         return 0;
  65                 }
  66                 fxf->next = xhead;
  67                 xhead = fxf;
  68         }
  69         chat("alloc \"%s\", dev=%d...", name, fd);
  70         fxf->name = strdup(name);
  71         fxf->ref = 1;
  72         fxf->qid = dir->qid;
  73         fxf->dev = fd;
  74         fxf->fmt = 0;
  75         fxf->ptr = 0;
  76         free(dir);
  77         if( ext2fs(fxf)<0 ){
  78                 xhead = fxf->next;
  79                 free(fxf);
  80                 unlock(&xlock);
  81                 return 0;
  82         }
  83         unlock(&xlock);
  84         return fxf;
  85 }
  86
  87 void
  88 refxfs(Xfs *xf, int delta)
  89 {
  90         lock(&xlock);
  91         xf->ref += delta;
  92         if(xf->ref == 0){
  93                 /*mchat("free \"%s\", dev=%d...", xf->name, xf->dev);
  94                 dumpbuf();*/
  95                 CleanSuper(xf);
  96                 syncbuf();
  97                 free(xf->name);
  98                 purgebuf(xf);
  99                 if(xf->dev >= 0){
 100                         close(xf->dev);
 101                         xf->dev = -1;
 102                 }
 103         }
 104         unlock(&xlock);
 105 }
 106
 107 Xfile *
 108 xfile(Fid *fid, int flag)
 109 {
 110         Xfile *f;
 111
 112         f = (Xfile*)fid->aux;
 113         switch(flag){
 114         default:
 115                 panic("xfile");
 116         case Asis:
 117                 return (f && f->xf && f->xf->dev < 0) ? 0 : f;
 118         case Clean:
 119                 if (f) chat("Clean and fid->aux already exists\n");
 120                 break;
 121         case Clunk:
 122                 if(f){
 123                         clean(f);
 124                         lock(&freelock);
 125                         f->next = freelist;
 126                         freelist = f;
 127                         unlock(&freelock);
 128                         fid->aux = 0;
 129                 }
 130                 return 0;
 131         }
 132         if(f)
 133                 return clean(f);
 134         lock(&freelock);
 135         if(f = freelist){       /* assign = */
 136                 freelist = f->next;
 137                 unlock(&freelock);
 138         } else {
 139                 unlock(&freelock);
 140                 f = malloc(sizeof(Xfile));
 141         }
 142         fid->aux = f;
 143         f->fid = fid->fid;
 144         f->client = client;
 145         f->xf = 0;
 146         f->ptr = 0;
 147         f->root = 0;
 148         return f;
 149 }
 150 Xfile *
 151 clean(Xfile *f)
 152 {
 153         if(f->xf && f->root){
 154                 refxfs(f->xf, -1);
 155                 f->xf = 0;
 156         }
 157         f->xf = 0;
 158         f->root = 0;
 159         f->dirindex = 0;
 160         return f;
 161 }