1 files changed, 513 insertions, 0 deletions

diff --git a/fs/umsdos/inode.c b/fs/umsdos/inode.c
new file mode 100644
index 000000000..40f7feb68
--- /dev/null
+++ b/fs/umsdos/inode.c
@@ -0,0 +1,513 @@
+/*
+ *  linux/fs/umsdos/inode.c
+ *
+ *	Written 1993 by Jacques Gelinas 
+ *	Inspired from linux/fs/msdos/... by Werner Almesberger
+ *
+ */
+
+#include <linux/fs.h>
+#include <linux/msdos_fs.h>
+#include <linux/kernel.h>
+#include <linux/sched.h>
+#include <linux/errno.h>
+#include <asm/segment.h>
+#include <linux/string.h>
+#include <linux/ctype.h>
+#include <linux/stat.h>
+#include <linux/umsdos_fs.h>
+
+#ifdef MODULE
+	#include <linux/module.h>
+	#include "../../tools/version.h"
+#endif
+
+struct inode *pseudo_root=NULL;		/* Useful to simulate the pseudo DOS */
+									/* directory. See UMSDOS_readdir_x() */
+
+/* #Specification: convention / PRINTK Printk and printk
+	Here is the convention for the use of printk inside fs/umsdos
+
+	printk carry important message (error or status).
+	Printk is for debugging (it is a macro defined at the beginning of
+		   most source.
+	PRINTK is a nulled Printk macro.
+
+	This convention makes the source easier to read, and Printk easier
+	to shut off.
+*/
+#define PRINTK(x)
+#define Printk(x) printk x
+
+
+void UMSDOS_put_inode(struct inode *inode)
+{
+	PRINTK (("put inode %x owner %x pos %d dir %x\n",inode
+		,inode->u.umsdos_i.i_emd_owner,inode->u.umsdos_i.pos
+		,inode->u.umsdos_i.i_emd_dir));
+	msdos_put_inode(inode);
+}
+
+
+void UMSDOS_put_super(struct super_block *sb)
+{
+	msdos_put_super(sb);
+	#ifdef MODULE
+		MOD_DEC_USE_COUNT;
+	#endif
+}
+
+
+void UMSDOS_statfs(struct super_block *sb,struct statfs *buf)
+{
+	msdos_statfs(sb,buf);
+}
+
+
+/*
+	Call msdos_lookup, but set back the original msdos function table.
+	Return 0 if ok, or a negative error code if not.
+*/
+int umsdos_real_lookup (
+	struct inode *dir,
+	const char *name,
+	int len,
+	struct inode **result)	/* Will hold inode of the file, if successful */
+{
+	int ret;
+	dir->i_count++;
+	ret = msdos_lookup (dir,name,len,result);
+	return ret;
+}
+/*
+	Complete the setup of an directory inode.
+	First, it completes the function pointers, then
+	it locates the EMD file. If the EMD is there, then plug the
+	umsdos function table. If not, use the msdos one.
+*/
+void umsdos_setup_dir_inode (struct inode *inode)
+{
+	inode->u.umsdos_i.i_emd_dir = 0;
+	{
+		struct inode *emd_dir = umsdos_emd_dir_lookup (inode,0);
+		extern struct inode_operations umsdos_rdir_inode_operations;
+		inode->i_op = emd_dir != NULL
+			? &umsdos_dir_inode_operations
+			: &umsdos_rdir_inode_operations;
+		iput (emd_dir);
+	}
+}
+/*
+	Add some info into an inode so it can find its owner quickly
+*/
+void umsdos_set_dirinfo(
+	struct inode *inode,
+	struct inode *dir,
+	off_t f_pos)
+{
+	struct inode *emd_owner = umsdos_emd_dir_lookup(dir,1);
+	inode->u.umsdos_i.i_dir_owner = dir->i_ino;
+	inode->u.umsdos_i.i_emd_owner = emd_owner->i_ino;
+	iput (emd_owner);
+	inode->u.umsdos_i.pos = f_pos;
+}
+/*
+	Tells if an Umsdos inode has been "patched" once.
+	Return != 0 if so.
+*/
+int umsdos_isinit (struct inode *inode)
+{
+#if	1
+	return inode->u.umsdos_i.i_emd_owner != 0;
+#elif 0
+	return inode->i_atime != 0;
+#else
+	return inode->i_count > 1;
+#endif
+}
+/*
+	Connect the proper tables in the inode and add some info.
+*/
+void umsdos_patch_inode (
+	struct inode *inode,
+	struct inode *dir,		/* May be NULL */
+	off_t f_pos)
+{
+	/*
+		This function is called very early to setup the inode, somewhat
+		too early (called by UMSDOS_read_inode). At this point, we can't
+		do to much, such as lookup up EMD files and so on. This causes
+		confusion in the kernel. This is why some initialisation
+		will be done when dir != NULL only.
+
+		UMSDOS do run piggy back on top of msdos fs. It looks like something
+		is missing in the VFS to accommodate stacked fs. Still unclear what
+		(quite honestly).
+
+		Well, maybe one! A new entry "may_unmount" which would allow
+		the stacked fs to allocate some inode permanently and release
+		them at the end. Doing that now introduce a problem. unmount
+		always fail because some inodes are in use.
+	*/
+	if (!umsdos_isinit(inode)){
+		inode->u.umsdos_i.i_emd_dir = 0;
+		if (S_ISREG(inode->i_mode)){
+			static char is_init = 0;
+			if (!is_init){
+				/*
+					I don't want to change the msdos file system code
+					so I get the address of some subroutine dynamically
+					once.
+				*/
+				umsdos_file_inode_operations.bmap = inode->i_op->bmap;
+				inode->i_op = &umsdos_file_inode_operations;
+				is_init = 1;
+			}
+			inode->i_op = &umsdos_file_inode_operations;
+		}else if (S_ISDIR(inode->i_mode)){
+			if (dir != NULL){
+				umsdos_setup_dir_inode(inode);
+			}
+		}else if (S_ISLNK(inode->i_mode)){
+			inode->i_op = &umsdos_symlink_inode_operations;
+		}else if (S_ISCHR(inode->i_mode)){
+			inode->i_op = &chrdev_inode_operations;
+		}else if (S_ISBLK(inode->i_mode)){
+			inode->i_op = &blkdev_inode_operations;
+		}else if (S_ISFIFO(inode->i_mode)){
+			init_fifo(inode);
+		}
+		if (dir != NULL){
+			/* #Specification: inode / umsdos info
+				The first time an inode is seen (inode->i_count == 1),
+				the inode number of the EMD file which control this inode
+				is tagged to this inode. It allows operation such
+				as notify_change to be handled.
+			*/
+			/*
+				This is done last because it also control the
+				status of umsdos_isinit()
+			*/
+			umsdos_set_dirinfo (inode,dir,f_pos);
+		}
+	}else if (dir != NULL){
+		/*
+			Test to see if the info is maintained.
+			This should be removed when the file system will be proven.
+		*/
+		struct inode *emd_owner = umsdos_emd_dir_lookup(dir,1);
+		iput (emd_owner);
+		if (emd_owner->i_ino != inode->u.umsdos_i.i_emd_owner){
+			printk ("UMSDOS: *** EMD_OWNER ??? *** ino = %ld %ld <> %ld "
+				,inode->i_ino,emd_owner->i_ino,inode->u.umsdos_i.i_emd_owner);
+		}
+	}
+}
+/*
+	Get the inode of the directory which owns this inode.
+	Return 0 if ok, -EIO if error.
+*/
+int umsdos_get_dirowner(
+	struct inode *inode,
+	struct inode **result)	/* Hold NULL if any error */
+							/* else, the inode of the directory */
+{
+	int ret = -EIO;
+	unsigned long ino = inode->u.umsdos_i.i_dir_owner;
+	*result = NULL;
+	if (ino == 0){
+		printk ("UMSDOS: umsdos_get_dirowner ino == 0\n");
+	}else{
+		struct inode *dir = *result = iget(inode->i_sb,ino);
+		if (dir != NULL){
+			umsdos_patch_inode (dir,NULL,0);
+			ret = 0;
+		}
+	}
+	return ret;
+}
+/*
+	Load an inode from disk.
+*/
+void UMSDOS_read_inode(struct inode *inode)
+{
+	PRINTK (("read inode %x ino = %d ",inode,inode->i_ino));
+	msdos_read_inode(inode);
+	PRINTK (("ino = %d %d\n",inode->i_ino,inode->i_count));
+	if (S_ISDIR(inode->i_mode)
+		&& (inode->u.umsdos_i.u.dir_info.creating != 0
+			|| inode->u.umsdos_i.u.dir_info.looking != 0
+			|| inode->u.umsdos_i.u.dir_info.p != NULL)){
+		Printk (("read inode %d %d %p\n"
+			,inode->u.umsdos_i.u.dir_info.creating
+			,inode->u.umsdos_i.u.dir_info.looking
+			,inode->u.umsdos_i.u.dir_info.p));
+	}
+	/* #Specification: Inode / post initialisation
+		To completely initialise an inode, we need access to the owner
+		directory, so we can locate more info in the EMD file. This is
+		not available the first time the inode is access, we use
+		a value in the inode to tell if it has been finally initialised.
+
+		At first, we have tried testing i_count but it was causing
+		problem. It is possible that two or more process use the
+		newly accessed inode. While the first one block during
+		the initialisation (probably while reading the EMD file), the
+		others believe all is well because i_count > 1. They go banana
+		with a broken inode. See umsdos_lookup_patch and umsdos_patch_inode.
+	*/
+	umsdos_patch_inode(inode,NULL,0);
+}
+
+/*
+	Update the disk with the inode content
+*/
+void UMSDOS_write_inode(struct inode *inode)
+{
+	struct iattr newattrs;
+
+	PRINTK (("UMSDOS_write_inode emd %d\n",inode->u.umsdos_i.i_emd_owner));
+	msdos_write_inode(inode);
+	newattrs.ia_mtime = inode->i_mtime;
+	newattrs.ia_atime = inode->i_atime;
+	newattrs.ia_ctime = inode->i_ctime;
+	newattrs.ia_valid = ATTR_MTIME | ATTR_ATIME | ATTR_CTIME;
+	/*
+		UMSDOS_notify_change is convenient to call here
+		to update the EMD entry associated with this inode.
+		But it has the side effect to re"dirt" the inode.
+	*/
+	UMSDOS_notify_change (inode, &newattrs);
+	inode->i_dirt = 0;
+}
+
+int UMSDOS_notify_change(struct inode *inode, struct iattr *attr)
+{
+	int ret = 0;
+
+	if ((ret = inode_change_ok(inode, attr)) != 0) 
+		return ret;
+
+	if (inode->i_nlink > 0){
+		/* #Specification: notify_change / i_nlink > 0
+			notify change is only done for inode with nlink > 0. An inode
+			with nlink == 0 is no longer associated with any entry in
+			the EMD file, so there is nothing to update.
+		*/
+		unsigned long i_emd_owner = inode->u.umsdos_i.i_emd_owner;
+		if (inode == inode->i_sb->s_mounted){
+			/* #Specification: root inode / attributes
+				I don't know yet how this should work. Normally
+				the attributes (permissions bits, owner, times) of
+				a directory are stored in the EMD file of its parent.
+
+				One thing we could do is store the attributes of the root
+				inode in its own EMD file. A simple entry named "." could
+				be used for this special case. It would be read once
+				when the file system is mounted and update in
+				UMSDOS_notify_change() (right here).
+
+				I am not sure of the behavior of the root inode for
+				a real UNIX file system. For now, this is a nop.
+			*/
+		}else if (i_emd_owner != 0xffffffff && i_emd_owner != 0){
+			/* This inode is not a EMD file nor an inode used internally
+				by MSDOS, so we can update its status.
+				See emd.c
+			*/
+			struct inode *emd_owner = iget (inode->i_sb,i_emd_owner);
+			PRINTK (("notify change %p ",inode));
+			if (emd_owner == NULL){
+				printk ("UMSDOS: emd_owner = NULL ???");
+				ret = -EPERM;
+			}else{
+				struct file filp;
+				struct umsdos_dirent entry;
+				filp.f_pos = inode->u.umsdos_i.pos;
+				filp.f_reada = 0;
+				PRINTK (("pos = %d ",filp.f_pos));
+				/* Read only the start of the entry since we don't touch */
+				/* the name */
+				ret = umsdos_emd_dir_read (emd_owner,&filp,(char*)&entry
+					,UMSDOS_REC_SIZE);
+				if (ret == 0){
+					if (attr->ia_valid & ATTR_UID) 
+						entry.uid = attr->ia_uid;
+					if (attr->ia_valid & ATTR_GID) 
+						entry.gid = attr->ia_gid;
+					if (attr->ia_valid & ATTR_MODE) 
+						entry.mode = attr->ia_mode;
+					if (attr->ia_valid & ATTR_ATIME) 
+						entry.atime = attr->ia_atime;
+					if (attr->ia_valid & ATTR_MTIME) 
+						entry.mtime = attr->ia_mtime;
+					if (attr->ia_valid & ATTR_CTIME) 
+						entry.ctime = attr->ia_ctime;
+
+					entry.nlink = inode->i_nlink;
+					filp.f_pos = inode->u.umsdos_i.pos;
+					ret = umsdos_emd_dir_write (emd_owner,&filp,(char*)&entry
+						,UMSDOS_REC_SIZE);
+
+					PRINTK (("notify pos %d ret %d nlink %d "
+						,inode->u.umsdos_i.pos
+						,ret,entry.nlink));
+					/* #Specification: notify_change / msdos fs
+						notify_change operation are done only on the
+						EMD file. The msdos fs is not even called.
+					*/
+				}
+				iput (emd_owner);
+			}
+			PRINTK (("\n"));
+		}
+	}
+	if (ret == 0) 
+		inode_setattr(inode, attr);
+	return ret;
+}
+
+/* #Specification: function name / convention
+	A simple convention for function name has been used in
+	the UMSDOS file system. First all function use the prefix
+	umsdos_ to avoid name clash with other part of the kernel.
+
+	And standard VFS entry point use the prefix UMSDOS (upper case)
+	so it's easier to tell them apart.
+*/
+
+static struct super_operations umsdos_sops = { 
+	UMSDOS_read_inode,
+	UMSDOS_notify_change,
+	UMSDOS_write_inode,
+	UMSDOS_put_inode,
+	UMSDOS_put_super,
+	NULL, /* added in 0.96c */
+	UMSDOS_statfs,
+	NULL
+};
+
+/*
+	Read the super block of an Extended MS-DOS FS.
+*/
+struct super_block *UMSDOS_read_super(
+	struct super_block *s,
+	void *data,
+	int silent)
+{
+	/* #Specification: mount / options
+		Umsdos run on top of msdos. Currently, it supports no
+		mount option, but happily pass all option received to
+		the msdos driver. I am not sure if all msdos mount option
+		make sense with Umsdos. Here are at least those who
+		are useful.
+			uid=
+			gid=
+
+		These options affect the operation of umsdos in directories
+		which do not have an EMD file. They behave like normal
+		msdos directory, with all limitation of msdos.
+	*/
+	struct super_block *sb = msdos_read_super(s,data,silent);
+	printk ("UMSDOS Alpha 0.5a (compatibility level %d.%d, fast msdos)\n"
+		,UMSDOS_VERSION,UMSDOS_RELEASE);
+	if (sb != NULL){
+		sb->s_op = &umsdos_sops;
+		PRINTK (("umsdos_read_super %p\n",sb->s_mounted));
+		umsdos_setup_dir_inode (sb->s_mounted);
+		PRINTK (("End umsdos_read_super\n"));
+		if (s == super_blocks){
+			/* #Specification: pseudo root / mount
+				When a umsdos fs is mounted, a special handling is done
+				if it is the root partition. We check for the presence
+				of the file /linux/etc/init or /linux/etc/rc.
+				If one is there, we do a chroot("/linux").
+
+				We check both because (see init/main.c) the kernel
+				try to exec init at different place and if it fails
+				it tries /bin/sh /etc/rc. To be consistent with
+				init/main.c, many more test would have to be done
+				to locate init. Any complain ?
+
+				The chroot is done manually in init/main.c but the
+				info (the inode) is located at mount time and store
+				in a global variable (pseudo_root) which is used at
+				different place in the umsdos driver. There is no
+				need to store this variable elsewhere because it
+				will always be one, not one per mount.
+
+				This feature allows the installation
+				of a linux system within a DOS system in a subdirectory.
+	
+				A user may install its linux stuff in c:\linux
+				avoiding any clash with existing DOS file and subdirectory.
+				When linux boots, it hides this fact, showing a normal
+				root directory with /etc /bin /tmp ...
+
+				The word "linux" is hardcoded in /usr/include/linux/umsdos_fs.h
+				in the macro UMSDOS_PSDROOT_NAME.
+			*/
+
+			struct inode *pseudo;
+			Printk (("Mounting root\n"));
+			if (umsdos_real_lookup (sb->s_mounted,UMSDOS_PSDROOT_NAME
+					,UMSDOS_PSDROOT_LEN,&pseudo)==0
+				&& S_ISDIR(pseudo->i_mode)){
+				struct inode *etc = NULL;
+				struct inode *rc = NULL;
+				Printk (("/%s is there\n",UMSDOS_PSDROOT_NAME));
+				if (umsdos_real_lookup (pseudo,"etc",3,&etc)==0
+					&& S_ISDIR(etc->i_mode)){
+					struct inode *init;
+					Printk (("/%s/etc is there\n",UMSDOS_PSDROOT_NAME));
+					if ((umsdos_real_lookup (etc,"init",4,&init)==0
+							&& S_ISREG(init->i_mode))
+						|| (umsdos_real_lookup (etc,"rc",2,&rc)==0
+							&& S_ISREG(rc->i_mode))){
+						umsdos_setup_dir_inode (pseudo);
+						Printk (("Activating pseudo root /%s\n",UMSDOS_PSDROOT_NAME));
+						pseudo_root = pseudo;
+						pseudo->i_count++;
+						pseudo = NULL;
+					}
+					iput (init);
+					iput (rc);
+				}
+				iput (etc);
+			}
+			iput (pseudo);
+		}
+		#ifdef MODULE
+			MOD_INC_USE_COUNT;
+		#endif
+	}
+	return sb;
+}
+
+
+#ifdef MODULE
+
+char kernel_version[] = UTS_RELEASE;
+
+static struct file_system_type umsdos_fs_type = {
+	UMSDOS_read_super, "umsdos", 1, NULL
+};
+
+int init_module(void)
+{
+	register_filesystem(&umsdos_fs_type);
+	return 0;
+}
+
+void cleanup_module(void)
+{
+	if (MOD_IN_USE)
+		printk("Umsdos: file system in use, remove delayed\n");
+	else
+	{
+		unregister_filesystem(&umsdos_fs_type);
+	}
+}
+
+#endif
+