[mirror_ubuntu-artful-kernel.git] / fs / minix / dir.c

/*
 *  linux/fs/minix/dir.c
 *
 *  Copyright (C) 1991, 1992 Linus Torvalds
 *
 *  minix directory handling functions
 *
 *  Updated to filesystem version 3 by Daniel Aragones
 */

#include "minix.h"
#include <linux/buffer_head.h>
#include <linux/highmem.h>
#include <linux/swap.h>

typedef struct minix_dir_entry minix_dirent;
typedef struct minix3_dir_entry minix3_dirent;

static int minix_readdir(struct file *, struct dir_context *);

const struct file_operations minix_dir_operations = {
	.llseek		= generic_file_llseek,
	.read		= generic_read_dir,
	.iterate_shared	= minix_readdir,
	.fsync		= generic_file_fsync,
};

static inline void dir_put_page(struct page *page)
{
	kunmap(page);
	put_page(page);
}

/*
 * Return the offset into page `page_nr' of the last valid
 * byte in that page, plus one.
 */
static unsigned
minix_last_byte(struct inode *inode, unsigned long page_nr)
{
	unsigned last_byte = PAGE_SIZE;

	if (page_nr == (inode->i_size >> PAGE_SHIFT))
		last_byte = inode->i_size & (PAGE_SIZE - 1);
	return last_byte;
}

static int dir_commit_chunk(struct page *page, loff_t pos, unsigned len)
{
	struct address_space *mapping = page->mapping;
	struct inode *dir = mapping->host;
	int err = 0;
	block_write_end(NULL, mapping, pos, len, len, page, NULL);

	if (pos+len > dir->i_size) {
		i_size_write(dir, pos+len);
		mark_inode_dirty(dir);
	}
	if (IS_DIRSYNC(dir))
		err = write_one_page(page);
	else
		unlock_page(page);
	return err;
}

static struct page * dir_get_page(struct inode *dir, unsigned long n)
{
	struct address_space *mapping = dir->i_mapping;
	struct page *page = read_mapping_page(mapping, n, NULL);
	if (!IS_ERR(page))
		kmap(page);
	return page;
}

static inline void *minix_next_entry(void *de, struct minix_sb_info *sbi)
{
	return (void*)((char*)de + sbi->s_dirsize);
}

static int minix_readdir(struct file *file, struct dir_context *ctx)
{
	struct inode *inode = file_inode(file);
	struct super_block *sb = inode->i_sb;
	struct minix_sb_info *sbi = minix_sb(sb);
	unsigned chunk_size = sbi->s_dirsize;
	unsigned long npages = dir_pages(inode);
	unsigned long pos = ctx->pos;
	unsigned offset;
	unsigned long n;

	ctx->pos = pos = ALIGN(pos, chunk_size);
	if (pos >= inode->i_size)
		return 0;

	offset = pos & ~PAGE_MASK;
	n = pos >> PAGE_SHIFT;

	for ( ; n < npages; n++, offset = 0) {
		char *p, *kaddr, *limit;
		struct page *page = dir_get_page(inode, n);

		if (IS_ERR(page))
			continue;
		kaddr = (char *)page_address(page);
		p = kaddr+offset;
		limit = kaddr + minix_last_byte(inode, n) - chunk_size;
		for ( ; p <= limit; p = minix_next_entry(p, sbi)) {
			const char *name;
			__u32 inumber;
			if (sbi->s_version == MINIX_V3) {
				minix3_dirent *de3 = (minix3_dirent *)p;
				name = de3->name;
				inumber = de3->inode;
	 		} else {
				minix_dirent *de = (minix_dirent *)p;
				name = de->name;
				inumber = de->inode;
			}
			if (inumber) {
				unsigned l = strnlen(name, sbi->s_namelen);
				if (!dir_emit(ctx, name, l,
					      inumber, DT_UNKNOWN)) {
					dir_put_page(page);
					return 0;
				}
			}
			ctx->pos += chunk_size;
		}
		dir_put_page(page);
	}
	return 0;
}

static inline int namecompare(int len, int maxlen,
	const char * name, const char * buffer)
{
	if (len < maxlen && buffer[len])
		return 0;
	return !memcmp(name, buffer, len);
}

/*
 *	minix_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.
 */
minix_dirent *minix_find_entry(struct dentry *dentry, struct page **res_page)
{
	const char * name = dentry->d_name.name;
	int namelen = dentry->d_name.len;
	struct inode * dir = d_inode(dentry->d_parent);
	struct super_block * sb = dir->i_sb;
	struct minix_sb_info * sbi = minix_sb(sb);
	unsigned long n;
	unsigned long npages = dir_pages(dir);
	struct page *page = NULL;
	char *p;

	char *namx;
	__u32 inumber;
	*res_page = NULL;

	for (n = 0; n < npages; n++) {
		char *kaddr, *limit;

		page = dir_get_page(dir, n);
		if (IS_ERR(page))
			continue;

		kaddr = (char*)page_address(page);
		limit = kaddr + minix_last_byte(dir, n) - sbi->s_dirsize;
		for (p = kaddr; p <= limit; p = minix_next_entry(p, sbi)) {
			if (sbi->s_version == MINIX_V3) {
				minix3_dirent *de3 = (minix3_dirent *)p;
				namx = de3->name;
				inumber = de3->inode;
 			} else {
				minix_dirent *de = (minix_dirent *)p;
				namx = de->name;
				inumber = de->inode;
			}
			if (!inumber)
				continue;
			if (namecompare(namelen, sbi->s_namelen, name, namx))
				goto found;
		}
		dir_put_page(page);
	}
	return NULL;

found:
	*res_page = page;
	return (minix_dirent *)p;
}

int minix_add_link(struct dentry *dentry, struct inode *inode)
{
	struct inode *dir = d_inode(dentry->d_parent);
	const char * name = dentry->d_name.name;
	int namelen = dentry->d_name.len;
	struct super_block * sb = dir->i_sb;
	struct minix_sb_info * sbi = minix_sb(sb);
	struct page *page = NULL;
	unsigned long npages = dir_pages(dir);
	unsigned long n;
	char *kaddr, *p;
	minix_dirent *de;
	minix3_dirent *de3;
	loff_t pos;
	int err;
	char *namx = NULL;
	__u32 inumber;

	/*
	 * We take care of directory expansion in the same loop
	 * This code plays outside i_size, so it locks the page
	 * to protect that region.
	 */
	for (n = 0; n <= npages; n++) {
		char *limit, *dir_end;

		page = dir_get_page(dir, n);
		err = PTR_ERR(page);
		if (IS_ERR(page))
			goto out;
		lock_page(page);
		kaddr = (char*)page_address(page);
		dir_end = kaddr + minix_last_byte(dir, n);
		limit = kaddr + PAGE_SIZE - sbi->s_dirsize;
		for (p = kaddr; p <= limit; p = minix_next_entry(p, sbi)) {
			de = (minix_dirent *)p;
			de3 = (minix3_dirent *)p;
			if (sbi->s_version == MINIX_V3) {
				namx = de3->name;
				inumber = de3->inode;
		 	} else {
  				namx = de->name;
				inumber = de->inode;
			}
			if (p == dir_end) {
				/* We hit i_size */
				if (sbi->s_version == MINIX_V3)
					de3->inode = 0;
		 		else
					de->inode = 0;
				goto got_it;
			}
			if (!inumber)
				goto got_it;
			err = -EEXIST;
			if (namecompare(namelen, sbi->s_namelen, name, namx))
				goto out_unlock;
		}
		unlock_page(page);
		dir_put_page(page);
	}
	BUG();
	return -EINVAL;

got_it:
	pos = page_offset(page) + p - (char *)page_address(page);
	err = minix_prepare_chunk(page, pos, sbi->s_dirsize);
	if (err)
		goto out_unlock;
	memcpy (namx, name, namelen);
	if (sbi->s_version == MINIX_V3) {
		memset (namx + namelen, 0, sbi->s_dirsize - namelen - 4);
		de3->inode = inode->i_ino;
	} else {
		memset (namx + namelen, 0, sbi->s_dirsize - namelen - 2);
		de->inode = inode->i_ino;
	}
	err = dir_commit_chunk(page, pos, sbi->s_dirsize);
	dir->i_mtime = dir->i_ctime = current_time(dir);
	mark_inode_dirty(dir);
out_put:
	dir_put_page(page);
out:
	return err;
out_unlock:
	unlock_page(page);
	goto out_put;
}

int minix_delete_entry(struct minix_dir_entry *de, struct page *page)
{
	struct inode *inode = page->mapping->host;
	char *kaddr = page_address(page);
	loff_t pos = page_offset(page) + (char*)de - kaddr;
	struct minix_sb_info *sbi = minix_sb(inode->i_sb);
	unsigned len = sbi->s_dirsize;
	int err;

	lock_page(page);
	err = minix_prepare_chunk(page, pos, len);
	if (err == 0) {
		if (sbi->s_version == MINIX_V3)
			((minix3_dirent *) de)->inode = 0;
		else
			de->inode = 0;
		err = dir_commit_chunk(page, pos, len);
	} else {
		unlock_page(page);
	}
	dir_put_page(page);
	inode->i_ctime = inode->i_mtime = current_time(inode);
	mark_inode_dirty(inode);
	return err;
}

int minix_make_empty(struct inode *inode, struct inode *dir)
{
	struct page *page = grab_cache_page(inode->i_mapping, 0);
	struct minix_sb_info *sbi = minix_sb(inode->i_sb);
	char *kaddr;
	int err;

	if (!page)
		return -ENOMEM;
	err = minix_prepare_chunk(page, 0, 2 * sbi->s_dirsize);
	if (err) {
		unlock_page(page);
		goto fail;
	}

	kaddr = kmap_atomic(page);
	memset(kaddr, 0, PAGE_SIZE);

	if (sbi->s_version == MINIX_V3) {
		minix3_dirent *de3 = (minix3_dirent *)kaddr;

		de3->inode = inode->i_ino;
		strcpy(de3->name, ".");
		de3 = minix_next_entry(de3, sbi);
		de3->inode = dir->i_ino;
		strcpy(de3->name, "..");
	} else {
		minix_dirent *de = (minix_dirent *)kaddr;

		de->inode = inode->i_ino;
		strcpy(de->name, ".");
		de = minix_next_entry(de, sbi);
		de->inode = dir->i_ino;
		strcpy(de->name, "..");
	}
	kunmap_atomic(kaddr);

	err = dir_commit_chunk(page, 0, 2 * sbi->s_dirsize);
fail:
	put_page(page);
	return err;
}

/*
 * routine to check that the specified directory is empty (for rmdir)
 */
int minix_empty_dir(struct inode * inode)
{
	struct page *page = NULL;
	unsigned long i, npages = dir_pages(inode);
	struct minix_sb_info *sbi = minix_sb(inode->i_sb);
	char *name;
	__u32 inumber;

	for (i = 0; i < npages; i++) {
		char *p, *kaddr, *limit;

		page = dir_get_page(inode, i);
		if (IS_ERR(page))
			continue;

		kaddr = (char *)page_address(page);
		limit = kaddr + minix_last_byte(inode, i) - sbi->s_dirsize;
		for (p = kaddr; p <= limit; p = minix_next_entry(p, sbi)) {
			if (sbi->s_version == MINIX_V3) {
				minix3_dirent *de3 = (minix3_dirent *)p;
				name = de3->name;
				inumber = de3->inode;
			} else {
				minix_dirent *de = (minix_dirent *)p;
				name = de->name;
				inumber = de->inode;
			}

			if (inumber != 0) {
				/* check for . and .. */
				if (name[0] != '.')
					goto not_empty;
				if (!name[1]) {
					if (inumber != inode->i_ino)
						goto not_empty;
				} else if (name[1] != '.')
					goto not_empty;
				else if (name[2])
					goto not_empty;
			}
		}
		dir_put_page(page);
	}
	return 1;

not_empty:
	dir_put_page(page);
	return 0;
}

/* Releases the page */
void minix_set_link(struct minix_dir_entry *de, struct page *page,
	struct inode *inode)
{
	struct inode *dir = page->mapping->host;
	struct minix_sb_info *sbi = minix_sb(dir->i_sb);
	loff_t pos = page_offset(page) +
			(char *)de-(char*)page_address(page);
	int err;

	lock_page(page);

	err = minix_prepare_chunk(page, pos, sbi->s_dirsize);
	if (err == 0) {
		if (sbi->s_version == MINIX_V3)
			((minix3_dirent *) de)->inode = inode->i_ino;
		else
			de->inode = inode->i_ino;
		err = dir_commit_chunk(page, pos, sbi->s_dirsize);
	} else {
		unlock_page(page);
	}
	dir_put_page(page);
	dir->i_mtime = dir->i_ctime = current_time(dir);
	mark_inode_dirty(dir);
}

struct minix_dir_entry * minix_dotdot (struct inode *dir, struct page **p)
{
	struct page *page = dir_get_page(dir, 0);
	struct minix_sb_info *sbi = minix_sb(dir->i_sb);
	struct minix_dir_entry *de = NULL;

	if (!IS_ERR(page)) {
		de = minix_next_entry(page_address(page), sbi);
		*p = page;
	}
	return de;
}

ino_t minix_inode_by_name(struct dentry *dentry)
{
	struct page *page;
	struct minix_dir_entry *de = minix_find_entry(dentry, &page);
	ino_t res = 0;

	if (de) {
		struct address_space *mapping = page->mapping;
		struct inode *inode = mapping->host;
		struct minix_sb_info *sbi = minix_sb(inode->i_sb);

		if (sbi->s_version == MINIX_V3)
			res = ((minix3_dirent *) de)->inode;
		else
			res = de->inode;
		dir_put_page(page);
	}
	return res;
}
Commit	Line	Data
1da177e4 LT	1	/*
	2	* linux/fs/minix/dir.c
	3	*
	4	* Copyright (C) 1991, 1992 Linus Torvalds
	5	*
	6	* minix directory handling functions
939b00df AB	7	*
939b00df AB	8	* Updated to filesystem version 3 by Daniel Aragones
1da177e4 LT	9	*/
	10
	11	#include "minix.h"
4a66af9e	12	#include <linux/buffer_head.h>
1da177e4	13	#include <linux/highmem.h>
4a66af9e	14	#include <linux/swap.h>
1da177e4 LT	15
1da177e4 LT	16	typedef struct minix_dir_entry minix_dirent;
939b00df	17	typedef struct minix3_dir_entry minix3_dirent;
1da177e4	18
80886298	19	static int minix_readdir(struct file , struct dir_context );
1da177e4	20
4b6f5d20	21	const struct file_operations minix_dir_operations = {
cc46759a	22	.llseek = generic_file_llseek,
1da177e4	23	.read = generic_read_dir,
3b0a3c1a	24	.iterate_shared = minix_readdir,
1b061d92	25	.fsync = generic_file_fsync,
1da177e4 LT	26	};
	27
	28	static inline void dir_put_page(struct page *page)
	29	{
	30	kunmap(page);
09cbfeaf	31	put_page(page);
1da177e4 LT	32	}
	33
	34	/*
	35	* Return the offset into page `page_nr' of the last valid
	36	* byte in that page, plus one.
	37	*/
	38	static unsigned
	39	minix_last_byte(struct inode *inode, unsigned long page_nr)
	40	{
09cbfeaf	41	unsigned last_byte = PAGE_SIZE;
1da177e4	42
09cbfeaf KS	43	if (page_nr == (inode->i_size >> PAGE_SHIFT))
09cbfeaf KS	44	last_byte = inode->i_size & (PAGE_SIZE - 1);
1da177e4 LT	45	return last_byte;
	46	}
	47
4a66af9e	48	static int dir_commit_chunk(struct page *page, loff_t pos, unsigned len)
1da177e4	49	{
4a66af9e NP	50	struct address_space *mapping = page->mapping;
4a66af9e NP	51	struct inode *dir = mapping->host;
1da177e4	52	int err = 0;
4a66af9e NP	53	block_write_end(NULL, mapping, pos, len, len, page, NULL);
	54
	55	if (pos+len > dir->i_size) {
	56	i_size_write(dir, pos+len);
	57	mark_inode_dirty(dir);
	58	}
1da177e4	59	if (IS_DIRSYNC(dir))
2b69c828	60	err = write_one_page(page);
1da177e4 LT	61	else
	62	unlock_page(page);
	63	return err;
	64	}
	65
	66	static struct page * dir_get_page(struct inode *dir, unsigned long n)
	67	{
	68	struct address_space *mapping = dir->i_mapping;
090d2b18	69	struct page *page = read_mapping_page(mapping, n, NULL);
49837a80	70	if (!IS_ERR(page))
1da177e4	71	kmap(page);
1da177e4	72	return page;
1da177e4 LT	73	}
	74
	75	static inline void minix_next_entry(void de, struct minix_sb_info *sbi)
	76	{
	77	return (void)((char)de + sbi->s_dirsize);
	78	}
	79
80886298	80	static int minix_readdir(struct file file, struct dir_context ctx)
1da177e4	81	{
80886298	82	struct inode *inode = file_inode(file);
1da177e4	83	struct super_block *sb = inode->i_sb;
1da177e4 LT	84	struct minix_sb_info *sbi = minix_sb(sb);
1da177e4 LT	85	unsigned chunk_size = sbi->s_dirsize;
80886298 AV	86	unsigned long npages = dir_pages(inode);
	87	unsigned long pos = ctx->pos;
	88	unsigned offset;
	89	unsigned long n;
1da177e4	90
642b704c	91	ctx->pos = pos = ALIGN(pos, chunk_size);
1da177e4	92	if (pos >= inode->i_size)
80886298 AV	93	return 0;
80886298 AV	94
09cbfeaf KS	95	offset = pos & ~PAGE_MASK;
09cbfeaf KS	96	n = pos >> PAGE_SHIFT;
1da177e4 LT	97
	98	for ( ; n < npages; n++, offset = 0) {
	99	char p, kaddr, *limit;
	100	struct page *page = dir_get_page(inode, n);
	101
	102	if (IS_ERR(page))
	103	continue;
	104	kaddr = (char *)page_address(page);
	105	p = kaddr+offset;
	106	limit = kaddr + minix_last_byte(inode, n) - chunk_size;
939b00df	107	for ( ; p <= limit; p = minix_next_entry(p, sbi)) {
80886298 AV	108	const char *name;
80886298 AV	109	__u32 inumber;
939b00df AB	110	if (sbi->s_version == MINIX_V3) {
	111	minix3_dirent de3 = (minix3_dirent )p;
	112	name = de3->name;
	113	inumber = de3->inode;
	114	} else {
	115	minix_dirent de = (minix_dirent )p;
	116	name = de->name;
	117	inumber = de->inode;
	118	}
	119	if (inumber) {
939b00df	120	unsigned l = strnlen(name, sbi->s_namelen);
80886298 AV	121	if (!dir_emit(ctx, name, l,
80886298 AV	122	inumber, DT_UNKNOWN)) {
1da177e4	123	dir_put_page(page);
80886298	124	return 0;
1da177e4 LT	125	}
1da177e4 LT	126	}
80886298	127	ctx->pos += chunk_size;
1da177e4 LT	128	}
	129	dir_put_page(page);
	130	}
1da177e4 LT	131	return 0;
	132	}
	133
	134	static inline int namecompare(int len, int maxlen,
	135	const char * name, const char * buffer)
	136	{
	137	if (len < maxlen && buffer[len])
	138	return 0;
	139	return !memcmp(name, buffer, len);
	140	}
	141
	142	/*
	143	* minix_find_entry()
	144	*
	145	* finds an entry in the specified directory with the wanted name. It
	146	* returns the cache buffer in which the entry was found, and the entry
	147	* itself (as a parameter - res_dir). It does NOT read the inode of the
	148	* entry - you'll have to do that yourself if you want to.
	149	*/
	150	minix_dirent minix_find_entry(struct dentry dentry, struct page **res_page)
	151	{
	152	const char * name = dentry->d_name.name;
	153	int namelen = dentry->d_name.len;
2b0143b5	154	struct inode * dir = d_inode(dentry->d_parent);
1da177e4 LT	155	struct super_block * sb = dir->i_sb;
	156	struct minix_sb_info * sbi = minix_sb(sb);
	157	unsigned long n;
	158	unsigned long npages = dir_pages(dir);
	159	struct page *page = NULL;
939b00df	160	char *p;
1da177e4	161
939b00df AB	162	char *namx;
939b00df AB	163	__u32 inumber;
1da177e4 LT	164	*res_page = NULL;
	165
	166	for (n = 0; n < npages; n++) {
939b00df AB	167	char kaddr, limit;
939b00df AB	168
1da177e4 LT	169	page = dir_get_page(dir, n);
	170	if (IS_ERR(page))
	171	continue;
	172
	173	kaddr = (char*)page_address(page);
939b00df AB	174	limit = kaddr + minix_last_byte(dir, n) - sbi->s_dirsize;
	175	for (p = kaddr; p <= limit; p = minix_next_entry(p, sbi)) {
	176	if (sbi->s_version == MINIX_V3) {
	177	minix3_dirent de3 = (minix3_dirent )p;
	178	namx = de3->name;
	179	inumber = de3->inode;
	180	} else {
	181	minix_dirent de = (minix_dirent )p;
	182	namx = de->name;
	183	inumber = de->inode;
	184	}
	185	if (!inumber)
1da177e4	186	continue;
939b00df	187	if (namecompare(namelen, sbi->s_namelen, name, namx))
1da177e4 LT	188	goto found;
	189	}
	190	dir_put_page(page);
	191	}
	192	return NULL;
	193
	194	found:
	195	*res_page = page;
939b00df	196	return (minix_dirent *)p;
1da177e4 LT	197	}
	198
	199	int minix_add_link(struct dentry dentry, struct inode inode)
	200	{
2b0143b5	201	struct inode *dir = d_inode(dentry->d_parent);
1da177e4 LT	202	const char * name = dentry->d_name.name;
	203	int namelen = dentry->d_name.len;
	204	struct super_block * sb = dir->i_sb;
	205	struct minix_sb_info * sbi = minix_sb(sb);
	206	struct page *page = NULL;
1da177e4 LT	207	unsigned long npages = dir_pages(dir);
1da177e4 LT	208	unsigned long n;
939b00df AB	209	char kaddr, p;
	210	minix_dirent *de;
	211	minix3_dirent *de3;
4a66af9e	212	loff_t pos;
1da177e4	213	int err;
939b00df AB	214	char *namx = NULL;
939b00df AB	215	__u32 inumber;
1da177e4 LT	216
	217	/*
	218	* We take care of directory expansion in the same loop
	219	* This code plays outside i_size, so it locks the page
	220	* to protect that region.
	221	*/
	222	for (n = 0; n <= npages; n++) {
939b00df	223	char limit, dir_end;
1da177e4 LT	224
	225	page = dir_get_page(dir, n);
	226	err = PTR_ERR(page);
	227	if (IS_ERR(page))
	228	goto out;
	229	lock_page(page);
	230	kaddr = (char*)page_address(page);
	231	dir_end = kaddr + minix_last_byte(dir, n);
09cbfeaf	232	limit = kaddr + PAGE_SIZE - sbi->s_dirsize;
939b00df AB	233	for (p = kaddr; p <= limit; p = minix_next_entry(p, sbi)) {
	234	de = (minix_dirent *)p;
	235	de3 = (minix3_dirent *)p;
	236	if (sbi->s_version == MINIX_V3) {
	237	namx = de3->name;
	238	inumber = de3->inode;
	239	} else {
	240	namx = de->name;
	241	inumber = de->inode;
	242	}
	243	if (p == dir_end) {
1da177e4	244	/* We hit i_size */
939b00df AB	245	if (sbi->s_version == MINIX_V3)
	246	de3->inode = 0;
	247	else
	248	de->inode = 0;
1da177e4 LT	249	goto got_it;
1da177e4 LT	250	}
939b00df	251	if (!inumber)
1da177e4 LT	252	goto got_it;
1da177e4 LT	253	err = -EEXIST;
939b00df	254	if (namecompare(namelen, sbi->s_namelen, name, namx))
1da177e4	255	goto out_unlock;
1da177e4 LT	256	}
	257	unlock_page(page);
	258	dir_put_page(page);
	259	}
	260	BUG();
	261	return -EINVAL;
	262
	263	got_it:
d6b54841	264	pos = page_offset(page) + p - (char *)page_address(page);
f4e420dc	265	err = minix_prepare_chunk(page, pos, sbi->s_dirsize);
1da177e4 LT	266	if (err)
1da177e4 LT	267	goto out_unlock;
939b00df AB	268	memcpy (namx, name, namelen);
	269	if (sbi->s_version == MINIX_V3) {
	270	memset (namx + namelen, 0, sbi->s_dirsize - namelen - 4);
	271	de3->inode = inode->i_ino;
	272	} else {
	273	memset (namx + namelen, 0, sbi->s_dirsize - namelen - 2);
	274	de->inode = inode->i_ino;
	275	}
4a66af9e	276	err = dir_commit_chunk(page, pos, sbi->s_dirsize);
02027d42	277	dir->i_mtime = dir->i_ctime = current_time(dir);
1da177e4 LT	278	mark_inode_dirty(dir);
	279	out_put:
	280	dir_put_page(page);
	281	out:
	282	return err;
	283	out_unlock:
	284	unlock_page(page);
	285	goto out_put;
	286	}
	287
	288	int minix_delete_entry(struct minix_dir_entry de, struct page page)
	289	{
f4e420dc	290	struct inode *inode = page->mapping->host;
1da177e4	291	char *kaddr = page_address(page);
4a66af9e	292	loff_t pos = page_offset(page) + (char*)de - kaddr;
9f6c1333 DG	293	struct minix_sb_info *sbi = minix_sb(inode->i_sb);
9f6c1333 DG	294	unsigned len = sbi->s_dirsize;
1da177e4 LT	295	int err;
	296
	297	lock_page(page);
f4e420dc	298	err = minix_prepare_chunk(page, pos, len);
1da177e4	299	if (err == 0) {
9f6c1333 DG	300	if (sbi->s_version == MINIX_V3)
	301	((minix3_dirent *) de)->inode = 0;
	302	else
	303	de->inode = 0;
4a66af9e	304	err = dir_commit_chunk(page, pos, len);
1da177e4 LT	305	} else {
	306	unlock_page(page);
	307	}
	308	dir_put_page(page);
02027d42	309	inode->i_ctime = inode->i_mtime = current_time(inode);
1da177e4 LT	310	mark_inode_dirty(inode);
	311	return err;
	312	}
	313
	314	int minix_make_empty(struct inode inode, struct inode dir)
	315	{
f4e420dc	316	struct page *page = grab_cache_page(inode->i_mapping, 0);
939b00df	317	struct minix_sb_info *sbi = minix_sb(inode->i_sb);
1da177e4 LT	318	char *kaddr;
	319	int err;
	320
	321	if (!page)
	322	return -ENOMEM;
f4e420dc	323	err = minix_prepare_chunk(page, 0, 2 * sbi->s_dirsize);
1da177e4 LT	324	if (err) {
	325	unlock_page(page);
	326	goto fail;
	327	}
	328
27a6d5c7	329	kaddr = kmap_atomic(page);
09cbfeaf	330	memset(kaddr, 0, PAGE_SIZE);
1da177e4	331
939b00df AB	332	if (sbi->s_version == MINIX_V3) {
	333	minix3_dirent de3 = (minix3_dirent )kaddr;
	334
	335	de3->inode = inode->i_ino;
	336	strcpy(de3->name, ".");
	337	de3 = minix_next_entry(de3, sbi);
	338	de3->inode = dir->i_ino;
	339	strcpy(de3->name, "..");
	340	} else {
	341	minix_dirent de = (minix_dirent )kaddr;
	342
	343	de->inode = inode->i_ino;
	344	strcpy(de->name, ".");
	345	de = minix_next_entry(de, sbi);
	346	de->inode = dir->i_ino;
	347	strcpy(de->name, "..");
	348	}
27a6d5c7	349	kunmap_atomic(kaddr);
1da177e4 LT	350
	351	err = dir_commit_chunk(page, 0, 2 * sbi->s_dirsize);
	352	fail:
09cbfeaf	353	put_page(page);
1da177e4 LT	354	return err;
	355	}
	356
	357	/*
	358	* routine to check that the specified directory is empty (for rmdir)
	359	*/
	360	int minix_empty_dir(struct inode * inode)
	361	{
	362	struct page *page = NULL;
	363	unsigned long i, npages = dir_pages(inode);
	364	struct minix_sb_info *sbi = minix_sb(inode->i_sb);
939b00df AB	365	char *name;
939b00df AB	366	__u32 inumber;
1da177e4 LT	367
1da177e4 LT	368	for (i = 0; i < npages; i++) {
939b00df	369	char p, kaddr, *limit;
1da177e4	370
939b00df	371	page = dir_get_page(inode, i);
1da177e4 LT	372	if (IS_ERR(page))
	373	continue;
	374
	375	kaddr = (char *)page_address(page);
939b00df AB	376	limit = kaddr + minix_last_byte(inode, i) - sbi->s_dirsize;
	377	for (p = kaddr; p <= limit; p = minix_next_entry(p, sbi)) {
	378	if (sbi->s_version == MINIX_V3) {
	379	minix3_dirent de3 = (minix3_dirent )p;
	380	name = de3->name;
	381	inumber = de3->inode;
	382	} else {
	383	minix_dirent de = (minix_dirent )p;
	384	name = de->name;
	385	inumber = de->inode;
	386	}
1da177e4	387
939b00df	388	if (inumber != 0) {
1da177e4	389	/* check for . and .. */
939b00df	390	if (name[0] != '.')
1da177e4	391	goto not_empty;
939b00df AB	392	if (!name[1]) {
939b00df AB	393	if (inumber != inode->i_ino)
1da177e4	394	goto not_empty;
939b00df	395	} else if (name[1] != '.')
1da177e4	396	goto not_empty;
939b00df	397	else if (name[2])
1da177e4 LT	398	goto not_empty;
1da177e4 LT	399	}
1da177e4 LT	400	}
	401	dir_put_page(page);
	402	}
	403	return 1;
	404
	405	not_empty:
	406	dir_put_page(page);
	407	return 0;
	408	}
	409
	410	/* Releases the page */
	411	void minix_set_link(struct minix_dir_entry de, struct page page,
	412	struct inode *inode)
	413	{
f4e420dc	414	struct inode *dir = page->mapping->host;
1da177e4	415	struct minix_sb_info *sbi = minix_sb(dir->i_sb);
4a66af9e NP	416	loff_t pos = page_offset(page) +
4a66af9e NP	417	(char )de-(char)page_address(page);
1da177e4 LT	418	int err;
	419
	420	lock_page(page);
4a66af9e	421
f4e420dc	422	err = minix_prepare_chunk(page, pos, sbi->s_dirsize);
1da177e4	423	if (err == 0) {
9f6c1333 DG	424	if (sbi->s_version == MINIX_V3)
	425	((minix3_dirent *) de)->inode = inode->i_ino;
	426	else
	427	de->inode = inode->i_ino;
4a66af9e	428	err = dir_commit_chunk(page, pos, sbi->s_dirsize);
1da177e4 LT	429	} else {
	430	unlock_page(page);
	431	}
	432	dir_put_page(page);
02027d42	433	dir->i_mtime = dir->i_ctime = current_time(dir);
1da177e4 LT	434	mark_inode_dirty(dir);
	435	}
	436
	437	struct minix_dir_entry * minix_dotdot (struct inode dir, struct page *p)
	438	{
	439	struct page *page = dir_get_page(dir, 0);
	440	struct minix_sb_info *sbi = minix_sb(dir->i_sb);
	441	struct minix_dir_entry *de = NULL;
	442
	443	if (!IS_ERR(page)) {
	444	de = minix_next_entry(page_address(page), sbi);
	445	*p = page;
	446	}
	447	return de;
	448	}
	449
	450	ino_t minix_inode_by_name(struct dentry *dentry)
	451	{
	452	struct page *page;
	453	struct minix_dir_entry *de = minix_find_entry(dentry, &page);
	454	ino_t res = 0;
	455
	456	if (de) {
9f6c1333 DG	457	struct address_space *mapping = page->mapping;
	458	struct inode *inode = mapping->host;
	459	struct minix_sb_info *sbi = minix_sb(inode->i_sb);
	460
	461	if (sbi->s_version == MINIX_V3)
	462	res = ((minix3_dirent *) de)->inode;
	463	else
	464	res = de->inode;
1da177e4 LT	465	dir_put_page(page);
	466	}
	467	return res;
	468	}