sys/src/cmd/disk/kfs/dentry.c

   1 #include        "all.h"
   2
   3 Dentry*
   4 getdir(Iobuf *p, int slot)
   5 {
   6         Dentry *d;
   7
   8         if(!p)
   9                 return 0;
  10         d = (Dentry*)p->iobuf + slot%DIRPERBUF;
  11         return d;
  12 }
  13
  14 void
  15 accessdir(Iobuf *p, Dentry *d, int f)
  16 {
  17         long t;
  18
  19         if(p && !isro(p->dev)) {
  20                 if(!(f & (FWRITE|FWSTAT)) && noatime)
  21                         return;
  22                 t = time(nil);
  23                 if(f & (FREAD|FWRITE|FWSTAT)){
  24                         d->atime = t;
  25                         p->flags |= Bmod;
  26                 }
  27                 if(f & FWRITE) {
  28                         d->mtime = t;
  29                         d->qid.version++;
  30                         p->flags |= Bmod;
  31                 }
  32         }
  33 }
  34
  35 void
  36 dbufread(Iobuf *p, Dentry *d, long a)
  37 {
  38         USED(p, d, a);
  39 }
  40
  41 long
  42 rel2abs(Iobuf *p, Dentry *d, long a, int tag, int putb)
  43 {
  44         long addr, qpath;
  45         Device dev;
  46
  47         if(a < 0) {
  48                 print("dnodebuf: neg\n");
  49                 return 0;
  50         }
  51         qpath = d->qid.path;
  52         dev = p->dev;
  53         if(a < NDBLOCK) {
  54                 addr = d->dblock[a];
  55                 if(!addr && tag) {
  56                         addr = balloc(dev, tag, qpath);
  57                         d->dblock[a] = addr;
  58                         p->flags |= Bmod|Bimm;
  59                 }
  60                 if(putb)
  61                         putbuf(p);
  62                 return addr;
  63         }
  64         a -= NDBLOCK;
  65         if(a < INDPERBUF) {
  66                 addr = d->iblock;
  67                 if(!addr && tag) {
  68                         addr = balloc(dev, Tind1, qpath);
  69                         d->iblock = addr;
  70                         p->flags |= Bmod|Bimm;
  71                 }
  72                 if(putb)
  73                         putbuf(p);
  74                 addr = indfetch(p, d, addr, a, Tind1, tag);
  75                 return addr;
  76         }
  77         a -= INDPERBUF;
  78         if(a < INDPERBUF2) {
  79                 addr = d->diblock;
  80                 if(!addr && tag) {
  81                         addr = balloc(dev, Tind2, qpath);
  82                         d->diblock = addr;
  83                         p->flags |= Bmod|Bimm;
  84                 }
  85                 if(putb)
  86                         putbuf(p);
  87                 addr = indfetch(p, d, addr, a/INDPERBUF, Tind2, Tind1);
  88                 addr = indfetch(p, d, addr, a%INDPERBUF, Tind1, tag);
  89                 return addr;
  90         }
  91         if(putb)
  92                 putbuf(p);
  93         print("dnodebuf: trip indirect\n");
  94         return 0;
  95 }
  96
  97 Iobuf*
  98 dnodebuf(Iobuf *p, Dentry *d, long a, int tag)
  99 {
 100         long addr;
 101
 102         addr = rel2abs(p, d, a, tag, 0);
 103         if(addr)
 104                 return getbuf(p->dev, addr, Bread);
 105         return 0;
 106 }
 107
 108 /*
 109  * same as dnodebuf but it calls putpuf(p)
 110  * to reduce interference.
 111  */
 112 Iobuf*
 113 dnodebuf1(Iobuf *p, Dentry *d, long a, int tag)
 114 {
 115         long addr;
 116         Device dev;
 117
 118         dev = p->dev;
 119         addr = rel2abs(p, d, a, tag, 1);
 120         if(addr)
 121                 return getbuf(dev, addr, Bread);
 122         return 0;
 123
 124 }
 125
 126 long
 127 indfetch(Iobuf *p, Dentry *d, long addr, long a, int itag, int tag)
 128 {
 129         Iobuf *bp;
 130
 131         if(!addr)
 132                 return 0;
 133         bp = getbuf(p->dev, addr, Bread);
 134         if(!bp || checktag(bp, itag, d->qid.path)) {
 135                 if(!bp) {
 136                         print("ind fetch bp = 0\n");
 137                         return 0;
 138                 }
 139                 print("ind fetch tag\n");
 140                 putbuf(bp);
 141                 return 0;
 142         }
 143         addr = ((long*)bp->iobuf)[a];
 144         if(!addr && tag) {
 145                 addr = balloc(p->dev, tag, d->qid.path);
 146                 if(addr) {
 147                         ((long*)bp->iobuf)[a] = addr;
 148                         bp->flags |= Bmod;
 149                         if(localfs || tag == Tdir)
 150                                 bp->flags |= Bimm;
 151                         settag(bp, itag, d->qid.path);
 152                 }
 153         }
 154         putbuf(bp);
 155         return addr;
 156 }
 157
 158 void
 159 dtrunc(Iobuf *p, Dentry *d)
 160 {
 161         int i;
 162
 163         bfree(p->dev, d->diblock, 2);
 164         d->diblock = 0;
 165         bfree(p->dev, d->iblock, 1);
 166         d->iblock = 0;
 167         for(i=NDBLOCK-1; i>=0; i--) {
 168                 bfree(p->dev, d->dblock[i], 0);
 169                 d->dblock[i] = 0;
 170         }
 171         d->size = 0;
 172         p->flags |= Bmod|Bimm;
 173         accessdir(p, d, FWRITE);
 174 }