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199 |
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/*
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* linux/fs/umsdos/rdir.c
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*
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* Written 1994 by Jacques Gelinas
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*
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* Extended MS-DOS directory pure MS-DOS handling functions
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* (For directory without EMD file).
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*/
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#include <linux/sched.h>
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#include <linux/fs.h>
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#include <linux/msdos_fs.h>
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#include <linux/errno.h>
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#include <linux/stat.h>
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#include <linux/limits.h>
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#include <linux/umsdos_fs.h>
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#include <linux/malloc.h>
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#include <asm/segment.h>
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#define PRINTK(x)
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#define Printk(x) printk x
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extern struct inode *pseudo_root;
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struct RDIR_FILLDIR {
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void *dirbuf;
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filldir_t filldir;
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int real_root;
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};
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static int rdir_filldir(
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void * buf,
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const char * name,
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int name_len,
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off_t offset,
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ino_t ino)
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{
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int ret = 0;
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struct RDIR_FILLDIR *d = (struct RDIR_FILLDIR*) buf;
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if (d->real_root){
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/* real root of a pseudo_rooted partition */
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if (name_len != UMSDOS_PSDROOT_LEN
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|| memcmp(name,UMSDOS_PSDROOT_NAME,UMSDOS_PSDROOT_LEN)!=0){
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/* So it is not the /linux directory */
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if (name_len == 2
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&& name[0] == '.'
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&& name[1] == '.'){
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/* Make sure the .. entry points back to the pseudo_root */
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ino = pseudo_root->i_ino;
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}
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ret = d->filldir (d->dirbuf,name,name_len,offset,ino);
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}
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}else{
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/* Any DOS directory */
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ret = d->filldir (d->dirbuf,name,name_len,offset,ino);
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}
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return ret;
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}
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static int UMSDOS_rreaddir (
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struct inode *dir,
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struct file *filp,
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void *dirbuf,
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filldir_t filldir)
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{
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struct RDIR_FILLDIR bufk;
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bufk.filldir = filldir;
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bufk.dirbuf = dirbuf;
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bufk.real_root = pseudo_root != NULL
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&& dir == dir->i_sb->s_mounted
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&& dir == pseudo_root->i_sb->s_mounted;
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return fat_readdir(dir,filp,&bufk,rdir_filldir);
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}
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/*
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Lookup into a non promoted directory.
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If the result is a directory, make sure we find out if it is
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a promoted one or not (calling umsdos_setup_dir_inode(inode)).
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*/
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int umsdos_rlookup_x(
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struct inode *dir,
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const char *name,
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int len,
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struct inode **result, /* Will hold inode of the file, if successful */
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int nopseudo) /* Don't care about pseudo root mode */
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/* so locating "linux" will work */
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{
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int ret;
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if (pseudo_root != NULL
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&& len == 2
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&& name[0] == '.'
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&& name[1] == '.'
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&& dir == dir->i_sb->s_mounted
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&& dir == pseudo_root->i_sb->s_mounted){
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*result = pseudo_root;
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pseudo_root->i_count++;
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ret = 0;
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/* #Specification: pseudo root / DOS/..
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In the real root directory (c:\), the directory ..
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is the pseudo root (c:\linux).
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*/
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}else{
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ret = umsdos_real_lookup (dir,name,len,result);
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if (ret == 0){
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struct inode *inode = *result;
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if (inode == pseudo_root && !nopseudo){
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/* #Specification: pseudo root / DOS/linux
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Even in the real root directory (c:\), the directory
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/linux won't show
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*/
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ret = -ENOENT;
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iput (pseudo_root);
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*result = NULL;
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}else if (S_ISDIR(inode->i_mode)){
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/* We must place the proper function table */
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/* depending if this is a MsDOS directory or an UMSDOS directory */
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umsdos_setup_dir_inode(inode);
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}
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}
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}
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iput (dir);
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return ret;
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}
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int UMSDOS_rlookup(
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struct inode *dir,
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const char *name,
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int len,
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struct inode **result) /* Will hold inode of the file, if successful */
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{
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return umsdos_rlookup_x(dir,name,len,result,0);
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}
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static int UMSDOS_rrmdir (
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struct inode *dir,
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const char *name,
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int len)
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{
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/* #Specification: dual mode / rmdir in a DOS directory
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In a DOS (not EMD in it) directory, we use a reverse strategy
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compared with an Umsdos directory. We assume that a subdirectory
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of a DOS directory is also a DOS directory. This is not always
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true (umssync may be used anywhere), but make sense.
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So we call msdos_rmdir() directly. If it failed with a -ENOTEMPTY
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then we check if it is a Umsdos directory. We check if it is
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really empty (only . .. and --linux-.--- in it). If it is true
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we remove the EMD and do a msdos_rmdir() again.
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In a Umsdos directory, we assume all subdirectory are also
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Umsdos directory, so we check the EMD file first.
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*/
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int ret;
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if (umsdos_is_pseudodos(dir,name,len)){
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/* #Specification: pseudo root / rmdir /DOS
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The pseudo sub-directory /DOS can't be removed!
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This is done even if the pseudo root is not a Umsdos
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directory anymore (very unlikely), but an accident (under
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MsDOS) is always possible.
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EPERM is returned.
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*/
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ret = -EPERM;
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}else{
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umsdos_lockcreate (dir);
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dir->i_count++;
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ret = msdos_rmdir (dir,name,len);
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if (ret == -ENOTEMPTY){
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struct inode *sdir;
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dir->i_count++;
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ret = UMSDOS_rlookup (dir,name,len,&sdir);
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PRINTK (("rrmdir lookup %d ",ret));
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if (ret == 0){
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int empty;
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if ((empty = umsdos_isempty (sdir)) != 0){
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PRINTK (("isempty %d i_count %ld ",empty,sdir->i_count));
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if (empty == 2){
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/*
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Not a Umsdos directory, so the previous msdos_rmdir
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was not lying :-)
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*/
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ret = -ENOTEMPTY;
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}else if (empty == 1){
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/* We have to removed the EMD file */
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ret = msdos_unlink(sdir,UMSDOS_EMD_FILE
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,UMSDOS_EMD_NAMELEN);
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sdir = NULL;
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if (ret == 0){
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dir->i_count++;
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ret = msdos_rmdir (dir,name,len);
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}
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}
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}else{
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ret = -ENOTEMPTY;
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}
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iput (sdir);
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}
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}
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umsdos_unlockcreate (dir);
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}
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iput (dir);
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return ret;
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}
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/* #Specification: dual mode / introduction
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One goal of UMSDOS is to allow a practical and simple coexistence
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between MsDOS and Linux in a single partition. Using the EMD file
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in each directory, UMSDOS add Unix semantics and capabilities to
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normal DOS file system. To help and simplify coexistence, here is
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the logic related to the EMD file.
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If it is missing, then the directory is managed by the MsDOS driver.
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The names are limited to DOS limits (8.3). No links, no device special
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and pipe and so on.
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If it is there, it is the directory. If it is there but empty, then
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the directory looks empty. The utility umssync allows synchronisation
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of the real DOS directory and the EMD.
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Whenever umssync is applied to a directory without EMD, one is
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created on the fly. The directory is promoted to full unix semantic.
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Of course, the ls command will show exactly the same content as before
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the umssync session.
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It is believed that the user/admin will promote directories to unix
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semantic as needed.
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The strategy to implement this is to use two function table (struct
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inode_operations). One for true UMSDOS directory and one for directory
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with missing EMD.
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Functions related to the DOS semantic (but aware of UMSDOS) generally
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have a "r" prefix (r for real) such as UMSDOS_rlookup, to differentiate
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from the one with full UMSDOS semantic.
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*/
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static struct file_operations umsdos_rdir_operations = {
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NULL, /* lseek - default */
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UMSDOS_dir_read, /* read */
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NULL, /* write - bad */
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UMSDOS_rreaddir, /* readdir */
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NULL, /* select - default */
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UMSDOS_ioctl_dir, /* ioctl - default */
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NULL, /* mmap */
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NULL, /* no special open code */
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NULL, /* no special release code */
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NULL /* fsync */
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};
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struct inode_operations umsdos_rdir_inode_operations = {
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&umsdos_rdir_operations, /* default directory file-ops */
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msdos_create, /* create */
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UMSDOS_rlookup, /* lookup */
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NULL, /* link */
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msdos_unlink, /* unlink */
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NULL, /* symlink */
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msdos_mkdir, /* mkdir */
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UMSDOS_rrmdir, /* rmdir */
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NULL, /* mknod */
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msdos_rename, /* rename */
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NULL, /* readlink */
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NULL, /* follow_link */
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NULL, /* readpage */
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NULL, /* writepage */
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NULL, /* bmap */
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NULL, /* truncate */
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NULL /* permission */
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};
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