Import of Linus's Linux 1.1.68

1 files changed, 848 insertions, 0 deletions

diff --git a/fs/xiafs/namei.c b/fs/xiafs/namei.c
new file mode 100644
index 000000000..0532b1754
--- /dev/null
+++ b/fs/xiafs/namei.c
@@ -0,0 +1,848 @@
+/*
+ *  Linux/fs/xiafs/namei.c
+ *
+ *  Copyright (C) Q. Frank Xia, 1993.
+ *  
+ *  Based on Linus' minix/namei.c
+ *  Copyright (C) Linus Torvalds, 1991, 1992.
+ * 
+ *  This software may be redistributed per Linux Copyright.
+ */
+
+#include <linux/sched.h>
+#include <linux/xia_fs.h>
+#include <linux/kernel.h>
+#include <linux/string.h>
+#include <linux/stat.h>
+#include <linux/fcntl.h>
+#include <linux/errno.h>
+#include <asm/segment.h>
+
+#include "xiafs_mac.h"
+
+#define RNDUP4(x)	((3+(u_long)(x)) & ~3)
+/*
+ * ok, we cannot use strncmp, as the name is not in our data space.
+ * Thus we'll have to use xiafs_match. No big problem. Match also makes
+ * some sanity tests.
+ *
+ * NOTE! unlike strncmp, xiafs_match returns 1 for success, 0 for failure.
+ */
+static int xiafs_match(int len, const char * name, struct xiafs_direct * dep)
+{
+    int i;
+
+    if (!dep || !dep->d_ino || len > _XIAFS_NAME_LEN)
+        return 0;
+    /* "" means "." ---> so paths like "/usr/lib//libc.a" work */
+    if (!len && (dep->d_name[0]=='.') && (dep->d_name[1]=='\0'))
+        return 1;
+    if (len != dep->d_name_len)
+        return 0;
+    for (i=0; i < len; i++)
+        if (*name++ != dep->d_name[i])
+	    return 0;
+    return 1;
+}
+
+/*
+ *	xiafs_find_entry()
+ *
+ * finds an entry in the specified directory with the wanted name. It
+ * returns the cache buffer in which the entry was found, and the entry
+ * itself (as a parameter - res_dir). It does NOT read the inode of the
+ * entry - you'll have to do that yourself if you want to.
+ */
+static struct buffer_head * 
+xiafs_find_entry(struct inode * inode, const char * name, int namelen, 
+	       struct xiafs_direct ** res_dir, struct xiafs_direct ** res_pre)
+{
+    int i, zones, pos;
+    struct buffer_head * bh;
+    struct xiafs_direct * dep, * dep_pre;
+
+    *res_dir = NULL;
+    if (!inode)
+        return NULL;
+    if (namelen > _XIAFS_NAME_LEN)
+        return NULL;
+
+    if (inode->i_size & (XIAFS_ZSIZE(inode->i_sb) - 1)) {
+        printk("XIA-FS: bad dir size (%s %d)\n", WHERE_ERR);
+	return NULL;
+    }
+    zones=inode->i_size >> XIAFS_ZSIZE_BITS(inode->i_sb);
+    for (i=0; i < zones; i++ ) {
+        bh = xiafs_bread(inode, i, 0);
+	if (!bh)
+	    continue;
+	dep_pre=dep=(struct xiafs_direct *)bh->b_data;
+	if (!i && (dep->d_rec_len != 12 || !dep->d_ino || 
+		   dep->d_name_len != 1 || strcmp(dep->d_name, "."))) {
+	    printk("XIA-FS: bad directory (%s %d)\n", WHERE_ERR);
+	    brelse(bh);
+	    return NULL;
+	}
+	pos = 0;
+	while ( pos < XIAFS_ZSIZE(inode->i_sb) ) {
+	    if (dep->d_ino > inode->i_sb->u.xiafs_sb.s_ninodes ||
+		dep->d_rec_len < 12 || 
+		dep->d_rec_len+(char *)dep > bh->b_data+XIAFS_ZSIZE(inode->i_sb) ||
+		dep->d_name_len + 8 > dep->d_rec_len || dep->d_name_len <= 0 ||
+		dep->d_name[dep->d_name_len] ) {
+	        brelse(bh);
+		return NULL;
+	    }
+	    if (xiafs_match(namelen, name, dep)) {
+	        *res_dir=dep;
+		if (res_pre) 
+		    *res_pre=dep_pre;
+		return bh;
+	    }
+	    pos += dep->d_rec_len;
+	    dep_pre=dep;
+	    dep=(struct xiafs_direct *)(bh->b_data + pos);
+	}
+	brelse(bh);
+	if (pos > XIAFS_ZSIZE(inode->i_sb)) {
+	    printk("XIA-FS: bad directory (%s %d)\n", WHERE_ERR);
+	    return NULL;
+	}
+    }
+    return NULL;
+}
+
+int xiafs_lookup(struct inode * dir, const char * name, int len,
+	       struct inode ** result)
+{
+    int ino;
+    struct xiafs_direct * dep;
+    struct buffer_head * bh;
+
+    *result = NULL;
+    if (!dir)
+        return -ENOENT;
+    if (!S_ISDIR(dir->i_mode)) {
+        iput(dir);
+	return -ENOENT;
+    }
+    if (!(bh = xiafs_find_entry(dir, name, len, &dep, NULL))) {
+        iput(dir);
+	return -ENOENT;
+    }
+    ino = dep->d_ino;
+    brelse(bh);
+    if (!(*result = iget(dir->i_sb, ino))) {
+        iput(dir);
+	return -EACCES;
+    }
+    iput(dir);
+    return 0;
+}
+
+/*
+ *	xiafs_add_entry()
+ *
+ * adds a file entry to the specified directory, using the same
+ * semantics as xiafs_find_entry(). It returns NULL if it failed.
+ *
+ * NOTE!! The inode part of 'de' is left at 0 - which means you
+ * may not sleep between calling this and putting something into
+ * the entry, as someone else might have used it while you slept.
+ */
+static struct buffer_head * xiafs_add_entry(struct inode * dir,
+	const char * name, int namelen, struct xiafs_direct ** res_dir, 
+	struct xiafs_direct ** res_pre)
+{
+    int i, pos, offset;
+    struct buffer_head * bh;
+    struct xiafs_direct * de, * de_pre;
+
+    *res_dir = NULL;
+    if (!dir || !namelen || namelen > _XIAFS_NAME_LEN)
+        return NULL;
+
+    if (dir->i_size & (XIAFS_ZSIZE(dir->i_sb) - 1)) {
+        printk("XIA-FS: bad dir size (%s %d)\n", WHERE_ERR);
+	return NULL;
+    }
+    pos=0;
+    for ( ; ; ) {
+        bh =  xiafs_bread(dir, pos >> XIAFS_ZSIZE_BITS(dir->i_sb), pos ? 1:0);
+	if (!bh)
+	    return NULL;
+	de_pre=de=(struct xiafs_direct *)bh->b_data;
+	if (!pos) {
+	    if (de->d_rec_len != 12 || !de->d_ino || de->d_name_len != 1 ||
+		strcmp(de->d_name, ".")) {
+	        printk("XIA-FS: bad directory (%s %d)\n", WHERE_ERR);
+		brelse(bh);
+		return NULL;
+	    }
+	    offset = 12;
+	    de_pre=de=(struct xiafs_direct *)(bh->b_data+12);
+	} else
+	    offset = 0;
+	while (offset < XIAFS_ZSIZE(dir->i_sb)) {
+	    if (pos >= dir->i_size) {
+	        de->d_ino=0;
+		de->d_name_len=0;
+		de->d_name[0]=0;
+		de->d_rec_len=XIAFS_ZSIZE(dir->i_sb);
+		dir->i_size += XIAFS_ZSIZE(dir->i_sb);
+		dir->i_dirt = 1;
+	    } else {
+	        if (de->d_ino > dir->i_sb->u.xiafs_sb.s_ninodes ||
+		    de->d_rec_len < 12 || 
+		    (char *)de+de->d_rec_len > bh->b_data+XIAFS_ZSIZE(dir->i_sb) ||
+		    de->d_name_len + 8 > de->d_rec_len ||
+		    de->d_name[de->d_name_len]) {
+		    printk("XIA-FS: bad directory entry (%s %d)\n", WHERE_ERR);
+		    brelse(bh);
+		    return NULL;
+		}
+		if (de->d_ino &&
+		    RNDUP4(de->d_name_len)+RNDUP4(namelen)+16<=de->d_rec_len) {
+		    i=RNDUP4(de->d_name_len)+8;
+		    de_pre=de;
+		    de=(struct xiafs_direct *)(i+(u_char *)de_pre);
+		    de->d_ino=0;
+		    de->d_rec_len=de_pre->d_rec_len-i;
+		    de_pre->d_rec_len=i;
+		}
+	    }
+	    if (!de->d_ino && RNDUP4(namelen)+8 <= de->d_rec_len) {
+		/*
+		 * XXX all times should be set by caller upon successful
+		 * completion.
+		 */
+	        dir->i_ctime = dir->i_mtime = CURRENT_TIME;
+		dir->i_dirt = 1;
+		memcpy(de->d_name, name, namelen);
+		de->d_name[namelen]=0;
+		de->d_name_len=namelen;
+		mark_buffer_dirty(bh, 1);
+		*res_dir = de;
+		if (res_pre)
+		    *res_pre = de_pre;
+		return bh;
+	    }
+	    offset+=de->d_rec_len;
+	    de_pre=de;
+	    de=(struct xiafs_direct *)(bh->b_data+offset);
+	}
+	brelse(bh);
+	if (offset > XIAFS_ZSIZE(dir->i_sb)) {
+	    printk("XIA-FS: bad directory (%s %d)\n", WHERE_ERR);
+	    return NULL;
+	}
+	pos+=XIAFS_ZSIZE(dir->i_sb);
+    }
+    return NULL;
+}
+
+int xiafs_create(struct inode * dir, const char * name, int len, int mode,
+	struct inode ** result)
+{
+    struct inode * inode;
+    struct buffer_head * bh;
+    struct xiafs_direct * de;
+
+    *result = NULL;
+    if (!dir)
+        return -ENOENT;
+    inode = xiafs_new_inode(dir);
+    if (!inode) {
+        iput(dir);
+	return -ENOSPC;
+    }
+    inode->i_op = &xiafs_file_inode_operations;
+    inode->i_mode = mode;
+    inode->i_dirt = 1;
+    bh = xiafs_add_entry(dir, name, len, &de, NULL);
+    if (!bh) {
+        inode->i_nlink--;
+	inode->i_dirt = 1;
+	iput(inode);
+	iput(dir);
+	return -ENOSPC;
+    }
+    de->d_ino = inode->i_ino;
+    mark_buffer_dirty(bh, 1);
+    brelse(bh);
+    iput(dir);
+    *result = inode;
+    return 0;
+}
+
+int xiafs_mknod(struct inode *dir, const char *name, int len, int mode, int rdev)
+{
+    struct inode * inode;
+    struct buffer_head * bh;
+    struct xiafs_direct * de;
+
+    if (!dir)
+        return -ENOENT;
+    bh = xiafs_find_entry(dir,name,len,&de, NULL);
+    if (bh) {
+        brelse(bh);
+	iput(dir);
+	return -EEXIST;
+    }
+    inode = xiafs_new_inode(dir);
+    if (!inode) {
+        iput(dir);
+	return -ENOSPC;
+    }
+    inode->i_uid = current->fsuid;
+    inode->i_mode = mode;
+    inode->i_op = NULL;
+    if (S_ISREG(inode->i_mode))
+        inode->i_op = &xiafs_file_inode_operations;
+    else if (S_ISDIR(inode->i_mode)) {
+        inode->i_op = &xiafs_dir_inode_operations;
+	if (dir->i_mode & S_ISGID)
+	    inode->i_mode |= S_ISGID;
+    }
+    else if (S_ISLNK(inode->i_mode))
+        inode->i_op = &xiafs_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 (S_ISBLK(mode) || S_ISCHR(mode))
+        inode->i_rdev = rdev;
+    inode->i_atime = inode->i_ctime = inode->i_atime = CURRENT_TIME;
+    inode->i_dirt = 1;
+    bh = xiafs_add_entry(dir, name, len, &de, NULL);
+    if (!bh) {
+        inode->i_nlink--;
+	inode->i_dirt = 1;
+	iput(inode);
+	iput(dir);
+	return -ENOSPC;
+    }
+    de->d_ino = inode->i_ino;
+    mark_buffer_dirty(bh, 1);
+    brelse(bh);
+    iput(dir);
+    iput(inode);
+    return 0;
+}
+
+int xiafs_mkdir(struct inode * dir, const char * name, int len, int mode)
+{
+    struct inode * inode;
+    struct buffer_head * bh, *dir_block;
+    struct xiafs_direct * de;
+	
+    bh = xiafs_find_entry(dir,name,len,&de, NULL);
+    if (bh) {
+        brelse(bh);
+	iput(dir);
+	return -EEXIST;
+    }
+    if (dir->i_nlink > 64000) {
+        iput(dir);
+        return -EMLINK;
+    }
+    inode = xiafs_new_inode(dir);
+    if (!inode) {
+        iput(dir);
+	return -ENOSPC;
+    }
+    inode->i_op = &xiafs_dir_inode_operations;
+    inode->i_size = XIAFS_ZSIZE(dir->i_sb);
+    inode->i_atime = inode->i_ctime = inode->i_mtime = CURRENT_TIME;
+    dir_block = xiafs_bread(inode,0,1);
+    if (!dir_block) {
+        iput(dir);
+	inode->i_nlink--;
+	inode->i_dirt = 1;
+	iput(inode);
+	return -ENOSPC;
+    }
+    de = (struct xiafs_direct *) dir_block->b_data;
+    de->d_ino=inode->i_ino;
+    strcpy(de->d_name,".");
+    de->d_name_len=1;
+    de->d_rec_len=12;
+    de =(struct xiafs_direct *)(12 + dir_block->b_data);
+    de->d_ino = dir->i_ino;
+    strcpy(de->d_name,"..");
+    de->d_name_len=2;
+    de->d_rec_len=XIAFS_ZSIZE(dir->i_sb)-12;
+    inode->i_nlink = 2;
+    mark_buffer_dirty(dir_block, 1);
+    brelse(dir_block);
+    inode->i_mode = S_IFDIR | (mode & S_IRWXUGO & ~current->fs->umask);
+    if (dir->i_mode & S_ISGID)
+        inode->i_mode |= S_ISGID;
+    inode->i_dirt = 1;
+    bh = xiafs_add_entry(dir, name, len, &de, NULL);
+    if (!bh) {
+        iput(dir);
+	inode->i_nlink=0;
+	iput(inode);
+	return -ENOSPC;
+    }
+    de->d_ino = inode->i_ino;
+    mark_buffer_dirty(bh, 1);
+    dir->i_nlink++;
+    dir->i_dirt = 1;
+    iput(dir);
+    iput(inode);
+    brelse(bh);
+    return 0;
+}
+
+/*
+ * routine to check that the specified directory is empty (for rmdir)
+ */
+static int empty_dir(struct inode * inode)
+{
+    int i, zones, offset;
+    struct buffer_head * bh;
+    struct xiafs_direct * de;
+
+    if (inode->i_size & (XIAFS_ZSIZE(inode->i_sb)-1) ) {
+        printk("XIA-FS: bad directory (%s %d)\n", WHERE_ERR);
+	return 1;
+    }
+
+    zones=inode->i_size >> XIAFS_ZSIZE_BITS(inode->i_sb);
+    for (i=0; i < zones; i++) {
+        bh =  xiafs_bread(inode, i, 0);
+	if (!i) {
+	    if (!bh) {
+	        printk("XIA-FS: bad directory (%s %d)\n", WHERE_ERR);
+		return 1;
+	    }
+	    de=(struct xiafs_direct *)bh->b_data;
+	    if (de->d_ino != inode->i_ino || strcmp(".", de->d_name) ||
+		    de->d_rec_len != 12 ) {
+	        printk("XIA-FS: bad directory (%s %d)\n", WHERE_ERR);
+		brelse(bh);
+		return 1;	 
+	    }
+	    de=(struct xiafs_direct *)(12 + bh->b_data);
+	    if (!de->d_ino || strcmp("..", de->d_name)) {
+	    	printk("XIA-FS: bad directory (%s %d)\n", WHERE_ERR);
+		brelse(bh);
+		return 1;
+	    }
+	    offset=de->d_rec_len+12;
+	}
+	else
+	    offset = 0;
+	if (!bh)
+	    continue;
+	while (offset < XIAFS_ZSIZE(inode->i_sb)) {
+	    de=(struct xiafs_direct *)(bh->b_data+offset);
+	    if (de->d_ino > inode->i_sb->u.xiafs_sb.s_ninodes ||
+		de->d_rec_len < 12 || 
+		(char *)de+de->d_rec_len > bh->b_data+XIAFS_ZSIZE(inode->i_sb) ||
+		de->d_name_len + 8 > de->d_rec_len ||
+		de->d_name[de->d_name_len]) {
+	        printk("XIA-FS: bad directory (%s %d)\n", WHERE_ERR);
+		brelse(bh);
+		return 1;
+	    }
+	    if (de->d_ino) {
+	        brelse(bh);
+		return 0;
+	    }
+	    offset+=de->d_rec_len;
+	}
+	brelse(bh);
+    }
+    return 1;
+}
+
+static void xiafs_rm_entry(struct xiafs_direct *de, struct xiafs_direct * de_pre)
+{
+    if (de==de_pre) {
+        de->d_ino=0;
+	return;
+    }
+    while (de_pre->d_rec_len+(u_char *)de_pre < (u_char *)de) {
+        if (de_pre->d_rec_len < 12) {
+	    printk("XIA-FS: bad directory entry (%s %d)\n", WHERE_ERR);
+	    return;
+	}
+        de_pre=(struct xiafs_direct *)(de_pre->d_rec_len+(u_char *)de_pre);
+    }
+    if (de_pre->d_rec_len+(u_char *)de_pre > (u_char *)de) {
+        printk("XIA-FS: bad directory entry (%s %d)\n", WHERE_ERR);
+	return;
+    }
+    de_pre->d_rec_len+=de->d_rec_len;
+}
+
+int xiafs_rmdir(struct inode * dir, const char * name, int len)
+{
+    int retval;
+    struct inode * inode;
+    struct buffer_head * bh;
+    struct xiafs_direct * de, * de_pre;
+
+    inode = NULL;
+    bh = xiafs_find_entry(dir, name, len, &de, &de_pre);
+    retval = -ENOENT;
+    if (!bh)
+        goto end_rmdir;
+    retval = -EPERM;
+    if (!(inode = iget(dir->i_sb, de->d_ino)))
+        goto end_rmdir;
+    if ((dir->i_mode & S_ISVTX) && !fsuser() &&
+            current->fsuid != inode->i_uid &&
+            current->fsuid != dir->i_uid)
+        goto end_rmdir;
+    if (inode->i_dev != dir->i_dev)
+        goto end_rmdir;
+    if (inode == dir)	/* we may not delete ".", but "../dir" is ok */
+        goto end_rmdir;
+    if (!S_ISDIR(inode->i_mode)) {
+        retval = -ENOTDIR;
+	goto end_rmdir;
+    }
+    if (!empty_dir(inode)) {
+        retval = -ENOTEMPTY;
+	goto end_rmdir;
+    }
+    if (inode->i_count > 1) {
+        retval = -EBUSY;
+	goto end_rmdir;
+    }
+    if (inode->i_nlink != 2)
+        printk("XIA-FS: empty directory has nlink!=2 (%s %d)\n", WHERE_ERR);
+    xiafs_rm_entry(de, de_pre);
+    mark_buffer_dirty(bh, 1);
+    inode->i_nlink=0;
+    inode->i_dirt=1;
+    dir->i_nlink--;
+    inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME;
+    dir->i_dirt=1;
+    retval = 0;
+end_rmdir:
+    iput(dir);
+    iput(inode);
+    brelse(bh);
+    return retval;
+}
+
+int xiafs_unlink(struct inode * dir, const char * name, int len)
+{
+    int retval;
+    struct inode * inode;
+    struct buffer_head * bh;
+    struct xiafs_direct * de, * de_pre;
+
+repeat:
+    retval = -ENOENT;
+    inode = NULL;
+    bh = xiafs_find_entry(dir, name, len, &de, &de_pre);
+    if (!bh)
+        goto end_unlink;
+    if (!(inode = iget(dir->i_sb, de->d_ino)))
+        goto end_unlink;
+    retval = -EPERM;
+    if (S_ISDIR(inode->i_mode))
+        goto end_unlink;
+    if (de->d_ino != inode->i_ino) {
+        iput(inode);
+	brelse(bh);
+	current->counter = 0;
+	schedule();
+	goto repeat;
+    }
+    if ((dir->i_mode & S_ISVTX) && !fsuser() &&
+	    current->fsuid != inode->i_uid &&
+	    current->fsuid != dir->i_uid)
+        goto end_unlink;
+    if (!inode->i_nlink) {
+        printk("XIA-FS: Deleting nonexistent file (%s %d)\n", WHERE_ERR);
+	inode->i_nlink=1;
+    }
+    xiafs_rm_entry(de, de_pre);
+    mark_buffer_dirty(bh, 1);
+    inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME;
+    dir->i_dirt = 1;
+    inode->i_nlink--;
+    inode->i_dirt = 1;
+    retval = 0;
+end_unlink:
+    brelse(bh);
+    iput(inode);
+    iput(dir);
+    return retval;
+}
+
+int xiafs_symlink(struct inode * dir, const char * name, 
+		int len, const char * symname)
+{
+    struct xiafs_direct * de;
+    struct inode * inode = NULL;
+    struct buffer_head * bh = NULL, * name_block = NULL;
+    int i;
+    char c;
+
+    bh = xiafs_find_entry(dir,name,len, &de, NULL);
+    if (bh) {
+	brelse(bh);
+	iput(dir);
+	return -EEXIST;
+    }
+    if (!(inode = xiafs_new_inode(dir))) {
+        iput(dir);
+	return -ENOSPC;
+    }
+    inode->i_mode = S_IFLNK | S_IRWXUGO;
+    inode->i_op = &xiafs_symlink_inode_operations;
+    name_block = xiafs_bread(inode,0,1);
+    if (!name_block) {
+        iput(dir);
+	inode->i_nlink--;
+	inode->i_dirt = 1;
+	iput(inode);
+	return -ENOSPC;
+    }
+    for (i = 0; i < BLOCK_SIZE-1 && (c=*symname++); i++)
+        name_block->b_data[i] = c;
+    name_block->b_data[i] = 0;
+    mark_buffer_dirty(name_block, 1);
+    brelse(name_block);
+    inode->i_size = i;
+    inode->i_dirt = 1;
+    bh = xiafs_add_entry(dir, name, len, &de, NULL);
+    if (!bh) {
+        inode->i_nlink--;
+	inode->i_dirt = 1;
+	iput(inode);
+	iput(dir);
+	return -ENOSPC;
+    }
+    de->d_ino = inode->i_ino;
+    mark_buffer_dirty(bh, 1);
+    brelse(bh);
+    iput(dir);
+    iput(inode);
+    return 0;
+}
+
+int xiafs_link(struct inode * oldinode, struct inode * dir, 
+	     const char * name, int len)
+{
+    struct xiafs_direct * de;
+    struct buffer_head * bh;
+
+    if (S_ISDIR(oldinode->i_mode)) {
+        iput(oldinode);
+	iput(dir);
+	return -EPERM;
+    }
+    if (oldinode->i_nlink > 64000) {
+        iput(oldinode);
+	iput(dir);
+	return -EMLINK;
+    }
+    bh = xiafs_find_entry(dir, name, len, &de, NULL);
+    if (bh) {
+        brelse(bh);
+	iput(dir);
+	iput(oldinode);
+	return -EEXIST;
+    }
+    bh = xiafs_add_entry(dir, name, len, &de, NULL);
+    if (!bh) {
+        iput(dir);
+	iput(oldinode);
+	return -ENOSPC;
+    }
+    de->d_ino = oldinode->i_ino;
+    mark_buffer_dirty(bh, 1);
+    brelse(bh);
+    iput(dir);
+    oldinode->i_nlink++;
+    oldinode->i_ctime = CURRENT_TIME;
+    oldinode->i_dirt = 1;
+    iput(oldinode);
+    return 0;
+}
+
+static int subdir(struct inode * new_inode, struct inode * old_inode)
+{
+    int ino;
+    int result;
+
+    new_inode->i_count++;
+    result = 0;
+    for (;;) {
+        if (new_inode == old_inode) {
+	    result = 1;
+	    break;
+	}
+	if (new_inode->i_dev != old_inode->i_dev)
+	    break;
+	ino = new_inode->i_ino;
+	if (xiafs_lookup(new_inode,"..",2,&new_inode))
+	    break;
+	if (new_inode->i_ino == ino)
+	    break;
+    }
+    iput(new_inode);
+    return result;
+}
+
+#define PARENT_INO(buffer) \
+    (((struct xiafs_direct *) ((u_char *)(buffer) + 12))->d_ino)
+
+/*
+ * rename uses retry to avoid race-conditions: at least they should be minimal.
+ * it tries to allocate all the blocks, then sanity-checks, and if the sanity-
+ * checks fail, it tries to restart itself again. Very practical - no changes
+ * are done until we know everything works ok.. and then all the changes can be
+ * done in one fell swoop when we have claimed all the buffers needed.
+ *
+ * Anybody can rename anything with this: the permission checks are left to the
+ * higher-level routines.
+ */
+static int do_xiafs_rename(struct inode * old_dir, const char * old_name, 
+			 int old_len, struct inode * new_dir, 
+			 const char * new_name, int new_len)
+{
+    struct inode * old_inode, * new_inode;
+    struct buffer_head * old_bh, * new_bh, * dir_bh;
+    struct xiafs_direct * old_de, * old_de_pre, * new_de, * new_de_pre;
+    int retval;
+
+try_again:
+    old_inode = new_inode = NULL;
+    old_bh = new_bh = dir_bh = NULL;
+    old_bh = xiafs_find_entry(old_dir, old_name, old_len, &old_de, &old_de_pre);
+    retval = -ENOENT;
+    if (!old_bh)
+        goto end_rename;
+    old_inode = __iget(old_dir->i_sb, old_de->d_ino, 0); /* don't cross mnt-points */
+    if (!old_inode)
+        goto end_rename;
+    retval = -EPERM;
+    if ((old_dir->i_mode & S_ISVTX) && 
+	    current->fsuid != old_inode->i_uid &&
+	    current->fsuid != old_dir->i_uid && !fsuser())
+        goto end_rename;
+    new_bh = xiafs_find_entry(new_dir, new_name, new_len, &new_de, NULL);
+    if (new_bh) {
+        new_inode = __iget(new_dir->i_sb, new_de->d_ino, 0);
+	if (!new_inode) {
+	    brelse(new_bh);
+	    new_bh = NULL;
+	}
+    }
+    if (new_inode == old_inode) {
+        retval = 0;
+	goto end_rename;
+    }
+    if (new_inode && S_ISDIR(new_inode->i_mode)) {
+        retval = -EEXIST;
+	goto end_rename;
+    }
+    retval = -EPERM;
+    if (new_inode && (new_dir->i_mode & S_ISVTX) && 
+	    current->fsuid != new_inode->i_uid &&
+ 	    current->fsuid != new_dir->i_uid && !fsuser())
+        goto end_rename;
+    if (S_ISDIR(old_inode->i_mode)) {
+        retval = -EEXIST;
+	if (new_bh)
+	    goto end_rename;
+	retval = -EACCES;
+	if (!permission(old_inode, MAY_WRITE))
+	    goto end_rename;
+	retval = -EINVAL;
+	if (subdir(new_dir, old_inode))
+	    goto end_rename;
+	retval = -EIO;
+	dir_bh = xiafs_bread(old_inode,0,0);
+	if (!dir_bh)
+	    goto end_rename;
+	if (PARENT_INO(dir_bh->b_data) != old_dir->i_ino)
+	    goto end_rename;
+	retval = -EMLINK;
+	if (new_dir->i_nlink > 64000)
+	    goto end_rename;
+    }
+    if (!new_bh)
+        new_bh = xiafs_add_entry(new_dir, new_name, new_len, &new_de, &new_de_pre);
+    retval = -ENOSPC;
+    if (!new_bh) 
+        goto end_rename;
+    /* sanity checking */
+    if ( (new_inode && (new_de->d_ino != new_inode->i_ino))
+	    || (new_de->d_ino && !new_inode)
+	    || (old_de->d_ino != old_inode->i_ino)) {
+        xiafs_rm_entry(new_de, new_de_pre);
+        brelse(old_bh);
+	brelse(new_bh);
+	brelse(dir_bh);
+	iput(old_inode);
+	iput(new_inode);
+	current->counter=0;
+	schedule();
+	goto try_again;
+    }
+    xiafs_rm_entry(old_de, old_de_pre);
+    new_de->d_ino = old_inode->i_ino;
+    if (new_inode) {
+        new_inode->i_nlink--;
+	new_inode->i_dirt = 1;
+    }
+    mark_buffer_dirty(old_bh, 1);
+    mark_buffer_dirty(new_bh, 1);
+    if (dir_bh) {
+        PARENT_INO(dir_bh->b_data) = new_dir->i_ino;
+	mark_buffer_dirty(dir_bh, 1);
+	old_dir->i_nlink--;
+	new_dir->i_nlink++;
+	old_dir->i_dirt = 1;
+	new_dir->i_dirt = 1;
+    }
+    retval = 0;
+end_rename:
+    brelse(dir_bh);
+    brelse(old_bh);
+    brelse(new_bh);
+    iput(old_inode);
+    iput(new_inode);
+    iput(old_dir);
+    iput(new_dir);
+    return retval;
+}
+
+/*
+ * Ok, rename also locks out other renames, as they can change the parent of
+ * a directory, and we don't want any races. Other races are checked for by
+ * "do_rename()", which restarts if there are inconsistencies.
+ *
+ * Note that there is no race between different filesystems: it's only within
+ * the same device that races occur: many renames can happen at once, as long
+ * as they are on different partitions.
+ */
+int xiafs_rename(struct inode * old_dir, const char * old_name, int old_len,
+	struct inode * new_dir, const char * new_name, int new_len)
+{
+    static struct wait_queue * wait = NULL;
+    static int lock = 0;
+    int result;
+
+    while (lock)
+        sleep_on(&wait);
+    lock = 1;
+    result = do_xiafs_rename(old_dir, old_name, old_len,
+			   new_dir, new_name, new_len);
+    lock = 0;
+    wake_up(&wait);
+    return result;
+}