WebSVN - shark - Rev 24 - /shark/branches/xen/fs/msdos/msdos

/*
* Project: HARTIK (HA-rd R-eal TI-me K-ernel)
*
* Coordinators: Giorgio Buttazzo <giorgio@sssup.it>
* Gerardo Lamastra <gerardo@sssup.it>
*
* Authors : Massimiliano Giorgi <massy@hartik.sssup.it>
* (see authors.txt for full list of hartik's authors)
*
* ReTiS Lab (Scuola Superiore S.Anna - Pisa - Italy)
*
* http://www.sssup.it
* http://retis.sssup.it
* http://hartik.sssup.it
*/

/*
* Copyright (C) 1999 Massimiliano Giorgi
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
*/

/*
* CVS : $Id: msdos_i.c,v 1.2 2002-10-28 08:24:43 pj Exp $
*
* File: $File$
* Revision: $Revision: 1.2 $
* Last update: $Date: 2002-10-28 08:24:43 $
*/

#include <fs/types.h>
#include <fs/const.h>
#include <fs/stat.h>
#include <fs/assert.h>

#include "dcache.h"
#include "fs.h"
#include "msdos.h"
#include "msdos/msdos.h"

#include "debug.h"

/*
* local DEBUG
*/

#define DEBUG_ADDCLUSTER KERN_DEBUG
#undef DEBUG_ADDCLUSTER

#define DEBUG_ADDCLUSTER_EXTRA KERN_DEBUG
#undef DEBUG_ADDCLUSTER_EXTRA

/**/

#ifdef DEBUG_ADDCLUSTER
#define printd0(fmt,args...) \
if (debug_info) printk(DEBUG_ADDCLUSTER fmt,##args)
#else
#define printd0(fmt,args...)
#endif

#if defined(DEBUG_ADDCLUSTER)&&defined(DEBUG_ADDCLUSTER_EXTRA)
#define printd1(fmt,args...) \
if (debug_info) printk(DEBUG_ADDCLUSTER fmt,##args)
#else
#define printd1(fmt,args...)
#endif

/*
*
*/

static char *chr2str(char*s, int n)
{
static char str[13];
_assert(n<13);
memcpy(str,s,n);
str[n]='\0';
return str;
}

void msdos_dump_direntry(struct directoryentry *ptr)
{
printk(KERN_DEBUG "status : 0x%02x",(int)ptr->name[0]);
printk(KERN_DEBUG "filename : '%s'",chr2str(ptr->name,8));
printk(KERN_DEBUG "ext : '%s'",chr2str(ptr->ext,3));
printk(KERN_DEBUG "attribute : 0x%02x",ptr->attribute);
printk(KERN_DEBUG "cluster : %04x",ptr->cluster);
printk(KERN_DEBUG "size : %li",(long)ptr->size);
printk(KERN_DEBUG "time : %li",(long)ptr->time);
}

/* what is the logical sector of a cluster into the fat */
static __inline __uint32_t __cluster2lsect(struct super_block *sb,
__uint16_t cluster)
{
return MSDOS_SB(sb).lfat+((__uint32_t)cluster*2)/SECTORSIZE;
}

/* what is the offset of a cluster into the fat */
static __inline __uint32_t __cluster2offs(__uint16_t cluster)
{
return ((__uint32_t)cluster*2)%SECTORSIZE;
}

/**/

static __inline__ void __lock(struct super_block *sb,
dcache_t *buf[],
__uint32_t lsect)
{
_assert(buf[0]==NULL);
buf[0]=dcache_lock(sb->sb_dev,lsect);
}

static __inline__ void __unlock(struct super_block *sb,
dcache_t *buf[])
{
_assert(buf[0]!=NULL);
dcache_unlock(buf[0]);
buf[0]=NULL;
}

static __inline__ void __acquire(struct super_block *sb,
dcache_t *buf[],
__uint32_t lsect)
{
int i=0;
_assert(buf[0]==NULL);
_assert(MSDOS_SB(sb).nfat<=MAXFATS);
for (i=0;i<MSDOS_SB(sb).nfat;i++) {
buf[i]=dcache_acquire(sb->sb_dev,lsect);
_assert(buf[i]!=NULL);
lsect+=MSDOS_SB(sb).spf;
}
}

static __inline__ void __release(struct super_block *sb,
dcache_t *buf[])
{
int i;
_assert(buf[0]!=NULL);
for (i=MSDOS_SB(sb).nfat-1;i>=0;i--) {
_assert(buf[i]!=NULL);
dcache_release(buf[i]);
}
buf[0]=NULL;
}

static __inline__ __uint16_t __getcluster(struct super_block *sb,
dcache_t *buf[],
__uint16_t offs)
{
_assert(buf[0]!=NULL);
return *(__uint16_t*)(buf[0]->buffer+offs);
}

static __inline__ void __setcluster(struct super_block *sb,
dcache_t *buf[],
__uint16_t offs,
__uint16_t val)
{
int i;
_assert(buf[0]!=NULL);
for (i=0;i<MSDOS_SB(sb).nfat;i++) {
_assert(buf[i]!=NULL);
*(__uint16_t*)(buf[i]->buffer+offs)=val;
dcache_dirty(buf[i]);
dcache_skipwt(buf[i]);
}
}

/*
*
*/

__uint16_t msdos_nextcluster(struct super_block *sb, __uint16_t cluster)
{
dcache_t *buf[MAXFATS];
__uint32_t lsect;
__uint16_t offs;
__uint16_t ret;

buf[0]=NULL;
lsect=__cluster2lsect(sb,cluster);
offs=__cluster2offs(cluster);

__lock(sb,buf,lsect);
ret=__getcluster(sb,buf,offs);
__unlock(sb,buf);

return ret;
}

void msdos_freecluster(struct super_block *sb, __uint16_t cluster)
{
dcache_t *buf[MAXFATS];
__uint32_t lsect;
__uint16_t offs;

buf[0]=NULL;
lsect=__cluster2lsect(sb,cluster);
offs=__cluster2offs(cluster);

__acquire(sb,buf,lsect);

_assert(__getcluster(sb,buf,offs)!=FREECLUSTER);
__setcluster(sb,buf,offs,FREECLUSTER);

__release(sb,buf);
return;
}

void msdos_lastcluster(struct super_block *sb, __uint16_t cluster)
{
dcache_t *buf[MAXFATS];
__uint32_t lsect;
__uint16_t offs;

buf[0]=NULL;
lsect=__cluster2lsect(sb,cluster);
offs=__cluster2offs(cluster);

__acquire(sb,buf,lsect);

//_assert(__getcluster(sb,buf,offs)==FREECLUSTER);
_assert(__getcluster(sb,buf,offs)!=LASTCLUSTER);
__setcluster(sb,buf,offs,LASTCLUSTER);

__release(sb,buf);
return;
}

__uint16_t msdos_addcluster(struct super_block *sb, __uint16_t lacluster)
{
dcache_t *buf[MAXFATS];
__uint32_t lsect;
__uint16_t offs;
__uint32_t olsect;
__uint16_t cluster,stcluster;

printd0("msdos_addcluster START");

stcluster=cluster=MSDOS_SB(sb).stclust;
olsect=0;
buf[0]=NULL;

printd0("searching from cluster 0x%04lx",(long)stcluster);

for (;;) {
lsect=__cluster2lsect(sb,cluster);
offs=__cluster2offs(cluster);

if (lsect>=MSDOS_SB(sb).lroot) {
cluster=STARTCLUSTER;
lsect=__cluster2lsect(sb,cluster);
offs=__cluster2offs(cluster);
_assert(lsect<MSDOS_SB(sb).lroot);
}

if (lsect!=olsect) {
if (buf[0]!=NULL) __release(sb,buf);
__acquire(sb,buf,lsect);
printd1("read sector %li",(long)lsect);
olsect=lsect;
}

if (__getcluster(sb,buf,offs)==FREECLUSTER) {
printd0("cluster 0x%04lx (into FAT lsect: %li) added to 0x%04lx",
(long)cluster,(long)lsect,(long)lacluster);
MSDOS_SB(sb).stclust=cluster;
__setcluster(sb,buf,offs,LASTCLUSTER);

/* if lacluster is not a cluster we do NOT change the FAT table!*/
if (lacluster==NO_CLUSTER) break;
__release(sb,buf);

lsect=__cluster2lsect(sb,lacluster);
offs=__cluster2offs(lacluster);
__acquire(sb,buf,lsect);
_assert(__getcluster(sb,buf,offs)==LASTCLUSTER);
__setcluster(sb,buf,offs,cluster);
break;
}

cluster++;
if (cluster==stcluster) {
cluster=NO_CLUSTER;
break;
}
}

__release(sb,buf);
printd0("msdos_addcluster END");
return cluster;
}

void msdos_freeclusterchain(struct super_block *sb, __uint16_t cluster)
{
dcache_t *buf[MAXFATS];
__uint32_t lsect;
__uint16_t offs;
__uint32_t olsect;

buf[0]=NULL;
olsect=0;

for (;;) {
lsect=__cluster2lsect(sb,cluster);
offs=__cluster2offs(cluster);

if (lsect!=olsect) {
if (buf[0]!=NULL) __release(sb,buf);
__acquire(sb,buf,lsect);
olsect=lsect;
}

cluster=__getcluster(sb,buf,offs);
_assert(cluster!=FREECLUSTER);
__setcluster(sb,buf,offs,FREECLUSTER);

if (cluster==LASTCLUSTER) break;
}

__release(sb,buf);
return;
}

/*
*
*/

/* from FS specific filename into 'de' to the general filename into 'str' */
int msdos_formatname(struct directoryentry *de, struct qstr *str)
{
char *s=str->name;
char *ptr=de->name;
int i;

if (*ptr==0x05) *s++=0xed;
else *s++=*ptr++;
i=sizeof(de->name)-1;
while (i-->0) {
if (*ptr==' '||*ptr=='\0') break;
*s++=*ptr++;
}

if (de->ext[0]!=' '&&de->ext[0]!='\0') {
*s++='.';
ptr=de->ext;
i=sizeof(de->ext);
while (i-->0) {
if (*ptr==' '||*ptr=='\0') break;
*s++=*ptr++;
}
}

*s++='\0';

str->nameptr=NULL;
return 0;
}

/* all filename are traslated in upper case */
#define _up(x) (((x)>='a'&&(x)<='z')?(x)-'a'+'A':(x))

/* from the general filename into 'str' to FS specific filename into 'de' */
int msdos_deformatname(struct qstr *str,struct directoryentry *de)
{
char *s=QSTRNAME(str);
char *ptr=de->name;
int i;

memset(de->name,' ',sizeof(de->name));
memset(de->ext,' ',sizeof(de->ext));

i=0;
for (i=0;i<sizeof(de->name);i++,s++,ptr++) {
if (*s=='.'||*s=='\0') break;
*ptr=_up(*s);
}
if (*s=='\0') return 0;

while (*s!='.') {
if (*s=='\0') return 0;
s++;
}

ptr=de->ext;
s++;
for (i=0;i<sizeof(de->name);i++,s++,ptr++) {
if (*s=='.'||*s=='\0') break;
*ptr=_up(*s);
}

return 0;
}

static int msdos_dummy_truncate(struct inode *in, __off_t len)
{
return -1;
}

static int msdos_truncate(struct inode *in, __off_t len)
{
int numclusters;
int cl,pcl;

if (len>=in->i_st.st_size) return 0;

if (len==0) {
msdos_freeclusterchain(in->i_sb,MSDOS_I(in).scluster);
MSDOS_I(in).scluster=FREE_CLUSTER;
in->i_st.st_size=0;
in->i_dirty=1;
return 0;
}

numclusters=(len-1)/(MSDOS_SB(in->i_sb).spc*(long)SECTORSIZE)+1;

/* walk on cluster chain */
pcl=-1;
cl=MSDOS_I(in).scluster;
while (numclusters-->0) {
pcl=cl;
cl=msdos_nextcluster(in->i_sb,cl);
}
if (cl!=LASTCLUSTER) {
_assert(pcl!=-1);
msdos_lastcluster(in->i_sb,pcl);
msdos_freeclusterchain(in->i_sb,cl);
}

in->i_st.st_size=len;
in->i_dirty=1;
return 0;
}

/* msdos_create_inode() and msdos_lockup() are very similar */
/* they should be share code */

static struct inode *msdos_create_inode(struct inode *in, struct dentry *den)
{
struct inode *in2;
struct directoryentry *de;
dcache_t *buf;
__uint32_t lsect;
__uint16_t ldisk;
__uint16_t cluster,prevcluster;
int flagroot;
int spc;
int i,j;
int res;

/* for safety ;-) */
if (!__S_ISDIR(in->i_st.st_mode)) return NULL;

flagroot=(((in->i_st.st_ino&CLUSTER_MASK)>>CLUSTER_SHIFT)==ROOT_CLUSTER);
if (flagroot) {
cluster=SPECIAL_CLUSTER;
lsect=MSDOS_SB(in->i_sb).lroot;
spc=MSDOS_SB(in->i_sb).rootsect;
} else {
cluster=MSDOS_I(in).scluster;
lsect=msdos_cluster2sector(in,cluster);
_assert(lsect!=(__uint32_t)-1);
spc=MSDOS_SB(in->i_sb).spc;
}

printk1("msdos create inode: start directory scanning");

ldisk=in->i_sb->sb_dev;
/* for every cluster... */
for (;;) {

/* for every sectors... */
for (j=0;j<spc;j++,lsect++) {
buf=dcache_acquire(ldisk,lsect);

printk1("msdos create inode: logical sector %li",(long)lsect);

if (buf==NULL) {
printk1("msdos create inode: can't read sector");
return NULL;
}

/* for every directory entry... */
de=(struct directoryentry *)(buf->buffer);
for (i=0;i<SECTORSIZE/DIRENTRYSIZE;i++) {

if (msdos_isfreeentry(de+i)) {
printk1("msdos create inode: found free entry");

in2=catch_inode();
printk1("-------------------");
if (in2==NULL) {
printk1("msdos create inode: can't get free inode!");
dcache_release(buf);
return NULL;
}

in2->i_sb=in->i_sb;
in2->i_st.st_ino=CLUOFF2INODE(cluster,j*SECTORSIZE/DIRENTRYSIZE+i);
res=in2->i_sb->sb_op->init_inode(in2);
if (res!=0) {
printk1("msdos create inode: can't init inode!");
free_inode(in2);
dcache_release(buf);
return NULL;
}

msdos_markentrybusy(de+i);
msdos_deformatname(&den->d_name,de+i);
dcache_dirty(buf);

dcache_release(buf);
return in2;
}

} /* end directory entry loop */

dcache_release(buf);

printk1("msdos create inode: next sector");

} /* end sector loop */

if (flagroot) {
printk1("msdos create inode : no free slot (can't add one)");
return NULL;
}

cluster=msdos_nextcluster(in->i_sb,prevcluster=cluster);
if (cluster==LASTCLUSTER) {
printk1("msdos create inode: no free slot (try to add one)");

cluster=msdos_addcluster(in->i_sb,prevcluster);
if (cluster==NO_CLUSTER) {
printk1("msdos create inode: can't add cluster");
return NULL;
}

/* zeroing the new cluster */
lsect=msdos_cluster2sector(in,cluster);
_assert(lsect!=(__uint32_t)-1);
for (j=0;j<spc;j++,lsect++) {
buf=dcache_acquire(ldisk,lsect);
_assert(buf!=NULL);
memset(buf->buffer,0,SECTORSIZE);
dcache_dirty(buf);
dcache_release(buf);
}

printk1("msdos create inode: added cluster");

}
lsect=msdos_cluster2sector(in,cluster);
_assert(lsect!=(__uint32_t)-1);

printk1("msdos create inode: next cluster");

} /* end cluster loop */

}

static struct inode *msdos_lookup(struct inode *in, struct dentry *den)
{
struct inode *in2;
struct directoryentry *de;
struct qstr str;
dcache_t *buf;
__uint32_t lsect;
__uint16_t ldisk;
__uint16_t cluster;
int flagroot;
int spc;
int i,j;
int res;

printk1("msdos lookup: START for %s",QSTRNAME(&(den->d_name)));

/* for safety ;-) */
if (!__S_ISDIR(in->i_st.st_mode)) return NULL;

printk1("msdos lookup: is directory... ok");

flagroot=(((in->i_st.st_ino&CLUSTER_MASK)>>CLUSTER_SHIFT)==ROOT_CLUSTER);
if (flagroot) {
cluster=SPECIAL_CLUSTER;
lsect=MSDOS_SB(in->i_sb).lroot;
spc=MSDOS_SB(in->i_sb).rootsect;
} else {
cluster=MSDOS_I(in).scluster;
lsect=msdos_cluster2sector(in,cluster);
_assert(lsect!=(__uint32_t)-1);
spc=MSDOS_SB(in->i_sb).spc;
}

printk1("msdos lookup: start directory scanning");

ldisk=in->i_sb->sb_dev;
/* for every cluster... */
for (;;) {

/* for every sectors... */
for (j=0;j<spc;j++,lsect++) {
buf=dcache_lock(ldisk,lsect);

printk1("msdos lookup: logical sector %li",(long)lsect);

if (buf==NULL) {
printk1("msdos lookup: can't read sector");
return NULL;
}

/* for every directory entry... */
de=(struct directoryentry *)(buf->buffer);
for (i=0;i<SECTORSIZE/DIRENTRYSIZE;i++) {
if (msdos_islastentry(de+i)) {
/* last entry... not found! */
dcache_unlock(buf);
printk1("msdos lookup: NOT found");
return NULL;
}

/* if it' an invalid entry (not a regular file or directory entry) */
if (msdos_isunvalidentry(de+i)) continue;

/* extract name */
res=msdos_formatname(de+i,&str);
if (res!=0) {
dcache_unlock(buf);
printk1("msdos lookup: can't extract filename");
return NULL;
}

printk1e("msdos lookup: filename '%s'",QSTRNAME(&str));

/* compare name and if found... */
if (den->d_op->d_compare(den,&den->d_name,&str)==0) {

printk1("msdos lookup: found");
in2=catch_inode();
printk1("-------------------");

if (in2==NULL) {
printk1("msdos lookup: can't get free inode!");
dcache_unlock(buf);
return NULL;
}
in2->i_sb=in->i_sb;
in2->i_st.st_ino=CLUOFF2INODE(cluster,j*SECTORSIZE/DIRENTRYSIZE+i);
res=in2->i_sb->sb_op->read_inode(in2);
if (res!=0) {
printk1("msdos lookup: can't read inode!");
free_inode(in2);
dcache_unlock(buf);
return NULL;
}

dcache_unlock(buf);
return in2;
}

} /* end directory entry loop */

dcache_unlock(buf);
printk1("msdos lookup: next sector");

} /* end sector loop */

if (flagroot) {
printk1("msdos lookup: NOT found (no other entry into root dir)");
return NULL;
}

cluster=msdos_nextcluster(in->i_sb,cluster);
if (cluster==0||cluster>=0xfff0) {
printk1("msdos lookup: NOT found (end cluster)");
return NULL;
}
lsect=msdos_cluster2sector(in,cluster);
_assert(lsect!=(__uint32_t)-1);

printk1("msdos lookup: next cluster");

} /* end cluster loop */

}

static int msdos_dummy_unlink(struct dentry *d)
{
return EROFS;
}

static int msdos_unlink(struct dentry *d)
{
printkd("msdos_unlink: START");

/* only one dentry can own this inode... */
_assert(d->d_inode->i_dlink==1);

/* nothing to do */

/* update link count */
d->d_inode->i_st.st_nlink--;
_assert(d->d_inode->i_st.st_nlink==0);

printkd("msdos_unlink: END");
return 0;
}

static void msdos_destroy(struct inode *in)
{
msdos_truncate(in,0);
return;
}

/* ----------------- */

struct inode_operations msdos_inode_ro_operations={
&msdos_file_ro_operations,
msdos_create_inode,
msdos_lookup,
msdos_dummy_unlink,
msdos_destroy,
msdos_dummy_truncate
};

struct inode_operations msdos_inode_rw_operations={
&msdos_file_rw_operations,
msdos_create_inode,
msdos_lookup,
msdos_unlink,
msdos_destroy,
msdos_truncate
};

/*
*
* for inlines
*
*/

int msdos_islastentry(struct directoryentry *de)
{
return (*((de)->name)==LASTENTRYCHAR);
}

int msdos_isunvalidentry(struct directoryentry *de)
{
return (*((de)->name)==ERASEDENTRYCHAR)||
((de)->attribute&ATTR_VOLUME)||
(msdos_islastentry(de));
}

Subversion Repositories shark

(root)/shark/branches/xen/fs/msdos/msdos_i.c - Rev 24