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

// SPDX-License-Identifier: GPL-2.0
/*
 *  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
b2441318	1	// SPDX-License-Identifier: GPL-2.0
1da177e4 LT	2	/*
	3	* linux/fs/minix/dir.c
	4	*
	5	* Copyright (C) 1991, 1992 Linus Torvalds
	6	*
	7	* minix directory handling functions
939b00df AB	8	*
939b00df AB	9	* Updated to filesystem version 3 by Daniel Aragones
1da177e4 LT	10	*/
	11
	12	#include "minix.h"
4a66af9e	13	#include <linux/buffer_head.h>
1da177e4	14	#include <linux/highmem.h>
4a66af9e	15	#include <linux/swap.h>
1da177e4 LT	16
1da177e4 LT	17	typedef struct minix_dir_entry minix_dirent;
939b00df	18	typedef struct minix3_dir_entry minix3_dirent;
1da177e4	19
80886298	20	static int minix_readdir(struct file , struct dir_context );
1da177e4	21
4b6f5d20	22	const struct file_operations minix_dir_operations = {
cc46759a	23	.llseek = generic_file_llseek,
1da177e4	24	.read = generic_read_dir,
3b0a3c1a	25	.iterate_shared = minix_readdir,
1b061d92	26	.fsync = generic_file_fsync,
1da177e4 LT	27	};
	28
	29	static inline void dir_put_page(struct page *page)
	30	{
	31	kunmap(page);
09cbfeaf	32	put_page(page);
1da177e4 LT	33	}
	34
	35	/*
	36	* Return the offset into page `page_nr' of the last valid
	37	* byte in that page, plus one.
	38	*/
	39	static unsigned
	40	minix_last_byte(struct inode *inode, unsigned long page_nr)
	41	{
09cbfeaf	42	unsigned last_byte = PAGE_SIZE;
1da177e4	43
09cbfeaf KS	44	if (page_nr == (inode->i_size >> PAGE_SHIFT))
09cbfeaf KS	45	last_byte = inode->i_size & (PAGE_SIZE - 1);
1da177e4 LT	46	return last_byte;
	47	}
	48
4a66af9e	49	static int dir_commit_chunk(struct page *page, loff_t pos, unsigned len)
1da177e4	50	{
4a66af9e NP	51	struct address_space *mapping = page->mapping;
4a66af9e NP	52	struct inode *dir = mapping->host;
1da177e4	53	int err = 0;
4a66af9e NP	54	block_write_end(NULL, mapping, pos, len, len, page, NULL);
	55
	56	if (pos+len > dir->i_size) {
	57	i_size_write(dir, pos+len);
	58	mark_inode_dirty(dir);
	59	}
1da177e4	60	if (IS_DIRSYNC(dir))
2b69c828	61	err = write_one_page(page);
1da177e4 LT	62	else
	63	unlock_page(page);
	64	return err;
	65	}
	66
	67	static struct page * dir_get_page(struct inode *dir, unsigned long n)
	68	{
	69	struct address_space *mapping = dir->i_mapping;
090d2b18	70	struct page *page = read_mapping_page(mapping, n, NULL);
49837a80	71	if (!IS_ERR(page))
1da177e4	72	kmap(page);
1da177e4	73	return page;
1da177e4 LT	74	}
	75
	76	static inline void minix_next_entry(void de, struct minix_sb_info *sbi)
	77	{
	78	return (void)((char)de + sbi->s_dirsize);
	79	}
	80
80886298	81	static int minix_readdir(struct file file, struct dir_context ctx)
1da177e4	82	{
80886298	83	struct inode *inode = file_inode(file);
1da177e4	84	struct super_block *sb = inode->i_sb;
1da177e4 LT	85	struct minix_sb_info *sbi = minix_sb(sb);
1da177e4 LT	86	unsigned chunk_size = sbi->s_dirsize;
80886298 AV	87	unsigned long npages = dir_pages(inode);
	88	unsigned long pos = ctx->pos;
	89	unsigned offset;
	90	unsigned long n;
1da177e4	91
642b704c	92	ctx->pos = pos = ALIGN(pos, chunk_size);
1da177e4	93	if (pos >= inode->i_size)
80886298 AV	94	return 0;
80886298 AV	95
09cbfeaf KS	96	offset = pos & ~PAGE_MASK;
09cbfeaf KS	97	n = pos >> PAGE_SHIFT;
1da177e4 LT	98
	99	for ( ; n < npages; n++, offset = 0) {
	100	char p, kaddr, *limit;
	101	struct page *page = dir_get_page(inode, n);
	102
	103	if (IS_ERR(page))
	104	continue;
	105	kaddr = (char *)page_address(page);
	106	p = kaddr+offset;
	107	limit = kaddr + minix_last_byte(inode, n) - chunk_size;
939b00df	108	for ( ; p <= limit; p = minix_next_entry(p, sbi)) {
80886298 AV	109	const char *name;
80886298 AV	110	__u32 inumber;
939b00df AB	111	if (sbi->s_version == MINIX_V3) {
	112	minix3_dirent de3 = (minix3_dirent )p;
	113	name = de3->name;
	114	inumber = de3->inode;
	115	} else {
	116	minix_dirent de = (minix_dirent )p;
	117	name = de->name;
	118	inumber = de->inode;
	119	}
	120	if (inumber) {
939b00df	121	unsigned l = strnlen(name, sbi->s_namelen);
80886298 AV	122	if (!dir_emit(ctx, name, l,
80886298 AV	123	inumber, DT_UNKNOWN)) {
1da177e4	124	dir_put_page(page);
80886298	125	return 0;
1da177e4 LT	126	}
1da177e4 LT	127	}
80886298	128	ctx->pos += chunk_size;
1da177e4 LT	129	}
	130	dir_put_page(page);
	131	}
1da177e4 LT	132	return 0;
	133	}
	134
	135	static inline int namecompare(int len, int maxlen,
	136	const char * name, const char * buffer)
	137	{
	138	if (len < maxlen && buffer[len])
	139	return 0;
	140	return !memcmp(name, buffer, len);
	141	}
	142
	143	/*
	144	* minix_find_entry()
	145	*
	146	* finds an entry in the specified directory with the wanted name. It
	147	* returns the cache buffer in which the entry was found, and the entry
	148	* itself (as a parameter - res_dir). It does NOT read the inode of the
	149	* entry - you'll have to do that yourself if you want to.
	150	*/
	151	minix_dirent minix_find_entry(struct dentry dentry, struct page **res_page)
	152	{
	153	const char * name = dentry->d_name.name;
	154	int namelen = dentry->d_name.len;
2b0143b5	155	struct inode * dir = d_inode(dentry->d_parent);
1da177e4 LT	156	struct super_block * sb = dir->i_sb;
	157	struct minix_sb_info * sbi = minix_sb(sb);
	158	unsigned long n;
	159	unsigned long npages = dir_pages(dir);
	160	struct page *page = NULL;
939b00df	161	char *p;
1da177e4	162
939b00df AB	163	char *namx;
939b00df AB	164	__u32 inumber;
1da177e4 LT	165	*res_page = NULL;
	166
	167	for (n = 0; n < npages; n++) {
939b00df AB	168	char kaddr, limit;
939b00df AB	169
1da177e4 LT	170	page = dir_get_page(dir, n);
	171	if (IS_ERR(page))
	172	continue;
	173
	174	kaddr = (char*)page_address(page);
939b00df AB	175	limit = kaddr + minix_last_byte(dir, n) - sbi->s_dirsize;
	176	for (p = kaddr; p <= limit; p = minix_next_entry(p, sbi)) {
	177	if (sbi->s_version == MINIX_V3) {
	178	minix3_dirent de3 = (minix3_dirent )p;
	179	namx = de3->name;
	180	inumber = de3->inode;
	181	} else {
	182	minix_dirent de = (minix_dirent )p;
	183	namx = de->name;
	184	inumber = de->inode;
	185	}
	186	if (!inumber)
1da177e4	187	continue;
939b00df	188	if (namecompare(namelen, sbi->s_namelen, name, namx))
1da177e4 LT	189	goto found;
	190	}
	191	dir_put_page(page);
	192	}
	193	return NULL;
	194
	195	found:
	196	*res_page = page;
939b00df	197	return (minix_dirent *)p;
1da177e4 LT	198	}
	199
	200	int minix_add_link(struct dentry dentry, struct inode inode)
	201	{
2b0143b5	202	struct inode *dir = d_inode(dentry->d_parent);
1da177e4 LT	203	const char * name = dentry->d_name.name;
	204	int namelen = dentry->d_name.len;
	205	struct super_block * sb = dir->i_sb;
	206	struct minix_sb_info * sbi = minix_sb(sb);
	207	struct page *page = NULL;
1da177e4 LT	208	unsigned long npages = dir_pages(dir);
1da177e4 LT	209	unsigned long n;
939b00df AB	210	char kaddr, p;
	211	minix_dirent *de;
	212	minix3_dirent *de3;
4a66af9e	213	loff_t pos;
1da177e4	214	int err;
939b00df AB	215	char *namx = NULL;
939b00df AB	216	__u32 inumber;
1da177e4 LT	217
	218	/*
	219	* We take care of directory expansion in the same loop
	220	* This code plays outside i_size, so it locks the page
	221	* to protect that region.
	222	*/
	223	for (n = 0; n <= npages; n++) {
939b00df	224	char limit, dir_end;
1da177e4 LT	225
	226	page = dir_get_page(dir, n);
	227	err = PTR_ERR(page);
	228	if (IS_ERR(page))
	229	goto out;
	230	lock_page(page);
	231	kaddr = (char*)page_address(page);
	232	dir_end = kaddr + minix_last_byte(dir, n);
09cbfeaf	233	limit = kaddr + PAGE_SIZE - sbi->s_dirsize;
939b00df AB	234	for (p = kaddr; p <= limit; p = minix_next_entry(p, sbi)) {
	235	de = (minix_dirent *)p;
	236	de3 = (minix3_dirent *)p;
	237	if (sbi->s_version == MINIX_V3) {
	238	namx = de3->name;
	239	inumber = de3->inode;
	240	} else {
	241	namx = de->name;
	242	inumber = de->inode;
	243	}
	244	if (p == dir_end) {
1da177e4	245	/* We hit i_size */
939b00df AB	246	if (sbi->s_version == MINIX_V3)
	247	de3->inode = 0;
	248	else
	249	de->inode = 0;
1da177e4 LT	250	goto got_it;
1da177e4 LT	251	}
939b00df	252	if (!inumber)
1da177e4 LT	253	goto got_it;
1da177e4 LT	254	err = -EEXIST;
939b00df	255	if (namecompare(namelen, sbi->s_namelen, name, namx))
1da177e4	256	goto out_unlock;
1da177e4 LT	257	}
	258	unlock_page(page);
	259	dir_put_page(page);
	260	}
	261	BUG();
	262	return -EINVAL;
	263
	264	got_it:
d6b54841	265	pos = page_offset(page) + p - (char *)page_address(page);
f4e420dc	266	err = minix_prepare_chunk(page, pos, sbi->s_dirsize);
1da177e4 LT	267	if (err)
1da177e4 LT	268	goto out_unlock;
939b00df AB	269	memcpy (namx, name, namelen);
	270	if (sbi->s_version == MINIX_V3) {
	271	memset (namx + namelen, 0, sbi->s_dirsize - namelen - 4);
	272	de3->inode = inode->i_ino;
	273	} else {
	274	memset (namx + namelen, 0, sbi->s_dirsize - namelen - 2);
	275	de->inode = inode->i_ino;
	276	}
4a66af9e	277	err = dir_commit_chunk(page, pos, sbi->s_dirsize);
02027d42	278	dir->i_mtime = dir->i_ctime = current_time(dir);
1da177e4 LT	279	mark_inode_dirty(dir);
	280	out_put:
	281	dir_put_page(page);
	282	out:
	283	return err;
	284	out_unlock:
	285	unlock_page(page);
	286	goto out_put;
	287	}
	288
	289	int minix_delete_entry(struct minix_dir_entry de, struct page page)
	290	{
f4e420dc	291	struct inode *inode = page->mapping->host;
1da177e4	292	char *kaddr = page_address(page);
4a66af9e	293	loff_t pos = page_offset(page) + (char*)de - kaddr;
9f6c1333 DG	294	struct minix_sb_info *sbi = minix_sb(inode->i_sb);
9f6c1333 DG	295	unsigned len = sbi->s_dirsize;
1da177e4 LT	296	int err;
	297
	298	lock_page(page);
f4e420dc	299	err = minix_prepare_chunk(page, pos, len);
1da177e4	300	if (err == 0) {
9f6c1333 DG	301	if (sbi->s_version == MINIX_V3)
	302	((minix3_dirent *) de)->inode = 0;
	303	else
	304	de->inode = 0;
4a66af9e	305	err = dir_commit_chunk(page, pos, len);
1da177e4 LT	306	} else {
	307	unlock_page(page);
	308	}
	309	dir_put_page(page);
02027d42	310	inode->i_ctime = inode->i_mtime = current_time(inode);
1da177e4 LT	311	mark_inode_dirty(inode);
	312	return err;
	313	}
	314
	315	int minix_make_empty(struct inode inode, struct inode dir)
	316	{
f4e420dc	317	struct page *page = grab_cache_page(inode->i_mapping, 0);
939b00df	318	struct minix_sb_info *sbi = minix_sb(inode->i_sb);
1da177e4 LT	319	char *kaddr;
	320	int err;
	321
	322	if (!page)
	323	return -ENOMEM;
f4e420dc	324	err = minix_prepare_chunk(page, 0, 2 * sbi->s_dirsize);
1da177e4 LT	325	if (err) {
	326	unlock_page(page);
	327	goto fail;
	328	}
	329
27a6d5c7	330	kaddr = kmap_atomic(page);
09cbfeaf	331	memset(kaddr, 0, PAGE_SIZE);
1da177e4	332
939b00df AB	333	if (sbi->s_version == MINIX_V3) {
	334	minix3_dirent de3 = (minix3_dirent )kaddr;
	335
	336	de3->inode = inode->i_ino;
	337	strcpy(de3->name, ".");
	338	de3 = minix_next_entry(de3, sbi);
	339	de3->inode = dir->i_ino;
	340	strcpy(de3->name, "..");
	341	} else {
	342	minix_dirent de = (minix_dirent )kaddr;
	343
	344	de->inode = inode->i_ino;
	345	strcpy(de->name, ".");
	346	de = minix_next_entry(de, sbi);
	347	de->inode = dir->i_ino;
	348	strcpy(de->name, "..");
	349	}
27a6d5c7	350	kunmap_atomic(kaddr);
1da177e4 LT	351
	352	err = dir_commit_chunk(page, 0, 2 * sbi->s_dirsize);
	353	fail:
09cbfeaf	354	put_page(page);
1da177e4 LT	355	return err;
	356	}
	357
	358	/*
	359	* routine to check that the specified directory is empty (for rmdir)
	360	*/
	361	int minix_empty_dir(struct inode * inode)
	362	{
	363	struct page *page = NULL;
	364	unsigned long i, npages = dir_pages(inode);
	365	struct minix_sb_info *sbi = minix_sb(inode->i_sb);
939b00df AB	366	char *name;
939b00df AB	367	__u32 inumber;
1da177e4 LT	368
1da177e4 LT	369	for (i = 0; i < npages; i++) {
939b00df	370	char p, kaddr, *limit;
1da177e4	371
939b00df	372	page = dir_get_page(inode, i);
1da177e4 LT	373	if (IS_ERR(page))
	374	continue;
	375
	376	kaddr = (char *)page_address(page);
939b00df AB	377	limit = kaddr + minix_last_byte(inode, i) - sbi->s_dirsize;
	378	for (p = kaddr; p <= limit; p = minix_next_entry(p, sbi)) {
	379	if (sbi->s_version == MINIX_V3) {
	380	minix3_dirent de3 = (minix3_dirent )p;
	381	name = de3->name;
	382	inumber = de3->inode;
	383	} else {
	384	minix_dirent de = (minix_dirent )p;
	385	name = de->name;
	386	inumber = de->inode;
	387	}
1da177e4	388
939b00df	389	if (inumber != 0) {
1da177e4	390	/* check for . and .. */
939b00df	391	if (name[0] != '.')
1da177e4	392	goto not_empty;
939b00df AB	393	if (!name[1]) {
939b00df AB	394	if (inumber != inode->i_ino)
1da177e4	395	goto not_empty;
939b00df	396	} else if (name[1] != '.')
1da177e4	397	goto not_empty;
939b00df	398	else if (name[2])
1da177e4 LT	399	goto not_empty;
1da177e4 LT	400	}
1da177e4 LT	401	}
	402	dir_put_page(page);
	403	}
	404	return 1;
	405
	406	not_empty:
	407	dir_put_page(page);
	408	return 0;
	409	}
	410
	411	/* Releases the page */
	412	void minix_set_link(struct minix_dir_entry de, struct page page,
	413	struct inode *inode)
	414	{
f4e420dc	415	struct inode *dir = page->mapping->host;
1da177e4	416	struct minix_sb_info *sbi = minix_sb(dir->i_sb);
4a66af9e NP	417	loff_t pos = page_offset(page) +
4a66af9e NP	418	(char )de-(char)page_address(page);
1da177e4 LT	419	int err;
	420
	421	lock_page(page);
4a66af9e	422
f4e420dc	423	err = minix_prepare_chunk(page, pos, sbi->s_dirsize);
1da177e4	424	if (err == 0) {
9f6c1333 DG	425	if (sbi->s_version == MINIX_V3)
	426	((minix3_dirent *) de)->inode = inode->i_ino;
	427	else
	428	de->inode = inode->i_ino;
4a66af9e	429	err = dir_commit_chunk(page, pos, sbi->s_dirsize);
1da177e4 LT	430	} else {
	431	unlock_page(page);
	432	}
	433	dir_put_page(page);
02027d42	434	dir->i_mtime = dir->i_ctime = current_time(dir);
1da177e4 LT	435	mark_inode_dirty(dir);
	436	}
	437
	438	struct minix_dir_entry * minix_dotdot (struct inode dir, struct page *p)
	439	{
	440	struct page *page = dir_get_page(dir, 0);
	441	struct minix_sb_info *sbi = minix_sb(dir->i_sb);
	442	struct minix_dir_entry *de = NULL;
	443
	444	if (!IS_ERR(page)) {
	445	de = minix_next_entry(page_address(page), sbi);
	446	*p = page;
	447	}
	448	return de;
	449	}
	450
	451	ino_t minix_inode_by_name(struct dentry *dentry)
	452	{
	453	struct page *page;
	454	struct minix_dir_entry *de = minix_find_entry(dentry, &page);
	455	ino_t res = 0;
	456
	457	if (de) {
9f6c1333 DG	458	struct address_space *mapping = page->mapping;
	459	struct inode *inode = mapping->host;
	460	struct minix_sb_info *sbi = minix_sb(inode->i_sb);
	461
	462	if (sbi->s_version == MINIX_V3)
	463	res = ((minix3_dirent *) de)->inode;
	464	else
	465	res = de->inode;
1da177e4 LT	466	dir_put_page(page);
	467	}
	468	return res;
	469	}