[linux.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 void dir_commit_chunk(struct page *page, loff_t pos, unsigned len)
{
	struct address_space *mapping = page->mapping;
	struct inode *dir = mapping->host;

	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);
	}
	unlock_page(page);
}

static int minix_handle_dirsync(struct inode *dir)
{
	int err;

	err = filemap_write_and_wait(dir->i_mapping);
	if (!err)
		err = sync_inode_metadata(dir, 1);
	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;
	}
	dir_commit_chunk(page, pos, sbi->s_dirsize);
	dir->i_mtime = inode_set_ctime_current(dir);
	mark_inode_dirty(dir);
	err = minix_handle_dirsync(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) {
		unlock_page(page);
		return err;
	}
	if (sbi->s_version == MINIX_V3)
		((minix3_dirent *)de)->inode = 0;
	else
		de->inode = 0;
	dir_commit_chunk(page, pos, len);
	inode->i_mtime = inode_set_ctime_current(inode);
	mark_inode_dirty(inode);
	return minix_handle_dirsync(inode);
}

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);

	dir_commit_chunk(page, 0, 2 * sbi->s_dirsize);
	err = minix_handle_dirsync(inode);
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 */
int 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) {
		unlock_page(page);
		return err;
	}
	if (sbi->s_version == MINIX_V3)
		((minix3_dirent *)de)->inode = inode->i_ino;
	else
		de->inode = inode->i_ino;
	dir_commit_chunk(page, pos, sbi->s_dirsize);
	dir->i_mtime = inode_set_ctime_current(dir);
	mark_inode_dirty(dir);
	return minix_handle_dirsync(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
f556e776	49	static void 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;
f556e776	53
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	}
f556e776 CH	60	unlock_page(page);
	61	}
	62
	63	static int minix_handle_dirsync(struct inode *dir)
	64	{
	65	int err;
	66
	67	err = filemap_write_and_wait(dir->i_mapping);
	68	if (!err)
	69	err = sync_inode_metadata(dir, 1);
1da177e4 LT	70	return err;
	71	}
	72
	73	static struct page * dir_get_page(struct inode *dir, unsigned long n)
	74	{
	75	struct address_space *mapping = dir->i_mapping;
090d2b18	76	struct page *page = read_mapping_page(mapping, n, NULL);
49837a80	77	if (!IS_ERR(page))
1da177e4	78	kmap(page);
1da177e4	79	return page;
1da177e4 LT	80	}
	81
	82	static inline void minix_next_entry(void de, struct minix_sb_info *sbi)
	83	{
	84	return (void)((char)de + sbi->s_dirsize);
	85	}
	86
80886298	87	static int minix_readdir(struct file file, struct dir_context ctx)
1da177e4	88	{
80886298	89	struct inode *inode = file_inode(file);
1da177e4	90	struct super_block *sb = inode->i_sb;
1da177e4 LT	91	struct minix_sb_info *sbi = minix_sb(sb);
1da177e4 LT	92	unsigned chunk_size = sbi->s_dirsize;
80886298 AV	93	unsigned long npages = dir_pages(inode);
	94	unsigned long pos = ctx->pos;
	95	unsigned offset;
	96	unsigned long n;
1da177e4	97
642b704c	98	ctx->pos = pos = ALIGN(pos, chunk_size);
1da177e4	99	if (pos >= inode->i_size)
80886298 AV	100	return 0;
80886298 AV	101
09cbfeaf KS	102	offset = pos & ~PAGE_MASK;
09cbfeaf KS	103	n = pos >> PAGE_SHIFT;
1da177e4 LT	104
	105	for ( ; n < npages; n++, offset = 0) {
	106	char p, kaddr, *limit;
	107	struct page *page = dir_get_page(inode, n);
	108
	109	if (IS_ERR(page))
	110	continue;
	111	kaddr = (char *)page_address(page);
	112	p = kaddr+offset;
	113	limit = kaddr + minix_last_byte(inode, n) - chunk_size;
939b00df	114	for ( ; p <= limit; p = minix_next_entry(p, sbi)) {
80886298 AV	115	const char *name;
80886298 AV	116	__u32 inumber;
939b00df AB	117	if (sbi->s_version == MINIX_V3) {
	118	minix3_dirent de3 = (minix3_dirent )p;
	119	name = de3->name;
	120	inumber = de3->inode;
	121	} else {
	122	minix_dirent de = (minix_dirent )p;
	123	name = de->name;
	124	inumber = de->inode;
	125	}
	126	if (inumber) {
939b00df	127	unsigned l = strnlen(name, sbi->s_namelen);
80886298 AV	128	if (!dir_emit(ctx, name, l,
80886298 AV	129	inumber, DT_UNKNOWN)) {
1da177e4	130	dir_put_page(page);
80886298	131	return 0;
1da177e4 LT	132	}
1da177e4 LT	133	}
80886298	134	ctx->pos += chunk_size;
1da177e4 LT	135	}
	136	dir_put_page(page);
	137	}
1da177e4 LT	138	return 0;
	139	}
	140
	141	static inline int namecompare(int len, int maxlen,
	142	const char * name, const char * buffer)
	143	{
	144	if (len < maxlen && buffer[len])
	145	return 0;
	146	return !memcmp(name, buffer, len);
	147	}
	148
	149	/*
	150	* minix_find_entry()
	151	*
	152	* finds an entry in the specified directory with the wanted name. It
	153	* returns the cache buffer in which the entry was found, and the entry
	154	* itself (as a parameter - res_dir). It does NOT read the inode of the
	155	* entry - you'll have to do that yourself if you want to.
	156	*/
	157	minix_dirent minix_find_entry(struct dentry dentry, struct page **res_page)
	158	{
	159	const char * name = dentry->d_name.name;
	160	int namelen = dentry->d_name.len;
2b0143b5	161	struct inode * dir = d_inode(dentry->d_parent);
1da177e4 LT	162	struct super_block * sb = dir->i_sb;
	163	struct minix_sb_info * sbi = minix_sb(sb);
	164	unsigned long n;
	165	unsigned long npages = dir_pages(dir);
	166	struct page *page = NULL;
939b00df	167	char *p;
1da177e4	168
939b00df AB	169	char *namx;
939b00df AB	170	__u32 inumber;
1da177e4 LT	171	*res_page = NULL;
	172
	173	for (n = 0; n < npages; n++) {
939b00df AB	174	char kaddr, limit;
939b00df AB	175
1da177e4 LT	176	page = dir_get_page(dir, n);
	177	if (IS_ERR(page))
	178	continue;
	179
	180	kaddr = (char*)page_address(page);
939b00df AB	181	limit = kaddr + minix_last_byte(dir, n) - sbi->s_dirsize;
	182	for (p = kaddr; p <= limit; p = minix_next_entry(p, sbi)) {
	183	if (sbi->s_version == MINIX_V3) {
	184	minix3_dirent de3 = (minix3_dirent )p;
	185	namx = de3->name;
	186	inumber = de3->inode;
	187	} else {
	188	minix_dirent de = (minix_dirent )p;
	189	namx = de->name;
	190	inumber = de->inode;
	191	}
	192	if (!inumber)
1da177e4	193	continue;
939b00df	194	if (namecompare(namelen, sbi->s_namelen, name, namx))
1da177e4 LT	195	goto found;
	196	}
	197	dir_put_page(page);
	198	}
	199	return NULL;
	200
	201	found:
	202	*res_page = page;
939b00df	203	return (minix_dirent *)p;
1da177e4 LT	204	}
	205
	206	int minix_add_link(struct dentry dentry, struct inode inode)
	207	{
2b0143b5	208	struct inode *dir = d_inode(dentry->d_parent);
1da177e4 LT	209	const char * name = dentry->d_name.name;
	210	int namelen = dentry->d_name.len;
	211	struct super_block * sb = dir->i_sb;
	212	struct minix_sb_info * sbi = minix_sb(sb);
	213	struct page *page = NULL;
1da177e4 LT	214	unsigned long npages = dir_pages(dir);
1da177e4 LT	215	unsigned long n;
939b00df AB	216	char kaddr, p;
	217	minix_dirent *de;
	218	minix3_dirent *de3;
4a66af9e	219	loff_t pos;
1da177e4	220	int err;
939b00df AB	221	char *namx = NULL;
939b00df AB	222	__u32 inumber;
1da177e4 LT	223
	224	/*
	225	* We take care of directory expansion in the same loop
	226	* This code plays outside i_size, so it locks the page
	227	* to protect that region.
	228	*/
	229	for (n = 0; n <= npages; n++) {
939b00df	230	char limit, dir_end;
1da177e4 LT	231
	232	page = dir_get_page(dir, n);
	233	err = PTR_ERR(page);
	234	if (IS_ERR(page))
	235	goto out;
	236	lock_page(page);
	237	kaddr = (char*)page_address(page);
	238	dir_end = kaddr + minix_last_byte(dir, n);
09cbfeaf	239	limit = kaddr + PAGE_SIZE - sbi->s_dirsize;
939b00df AB	240	for (p = kaddr; p <= limit; p = minix_next_entry(p, sbi)) {
	241	de = (minix_dirent *)p;
	242	de3 = (minix3_dirent *)p;
	243	if (sbi->s_version == MINIX_V3) {
	244	namx = de3->name;
	245	inumber = de3->inode;
	246	} else {
	247	namx = de->name;
	248	inumber = de->inode;
	249	}
	250	if (p == dir_end) {
1da177e4	251	/* We hit i_size */
939b00df AB	252	if (sbi->s_version == MINIX_V3)
	253	de3->inode = 0;
	254	else
	255	de->inode = 0;
1da177e4 LT	256	goto got_it;
1da177e4 LT	257	}
939b00df	258	if (!inumber)
1da177e4 LT	259	goto got_it;
1da177e4 LT	260	err = -EEXIST;
939b00df	261	if (namecompare(namelen, sbi->s_namelen, name, namx))
1da177e4	262	goto out_unlock;
1da177e4 LT	263	}
	264	unlock_page(page);
	265	dir_put_page(page);
	266	}
	267	BUG();
	268	return -EINVAL;
	269
	270	got_it:
d6b54841	271	pos = page_offset(page) + p - (char *)page_address(page);
f4e420dc	272	err = minix_prepare_chunk(page, pos, sbi->s_dirsize);
1da177e4 LT	273	if (err)
1da177e4 LT	274	goto out_unlock;
939b00df AB	275	memcpy (namx, name, namelen);
	276	if (sbi->s_version == MINIX_V3) {
	277	memset (namx + namelen, 0, sbi->s_dirsize - namelen - 4);
	278	de3->inode = inode->i_ino;
	279	} else {
	280	memset (namx + namelen, 0, sbi->s_dirsize - namelen - 2);
	281	de->inode = inode->i_ino;
	282	}
f556e776	283	dir_commit_chunk(page, pos, sbi->s_dirsize);
f7f43858	284	dir->i_mtime = inode_set_ctime_current(dir);
1da177e4	285	mark_inode_dirty(dir);
f556e776	286	err = minix_handle_dirsync(dir);
1da177e4 LT	287	out_put:
	288	dir_put_page(page);
	289	out:
	290	return err;
	291	out_unlock:
	292	unlock_page(page);
	293	goto out_put;
	294	}
	295
	296	int minix_delete_entry(struct minix_dir_entry de, struct page page)
	297	{
f4e420dc	298	struct inode *inode = page->mapping->host;
1da177e4	299	char *kaddr = page_address(page);
4a66af9e	300	loff_t pos = page_offset(page) + (char*)de - kaddr;
9f6c1333 DG	301	struct minix_sb_info *sbi = minix_sb(inode->i_sb);
9f6c1333 DG	302	unsigned len = sbi->s_dirsize;
1da177e4 LT	303	int err;
	304
	305	lock_page(page);
f4e420dc	306	err = minix_prepare_chunk(page, pos, len);
b61d15d5	307	if (err) {
1da177e4	308	unlock_page(page);
b61d15d5	309	return err;
1da177e4	310	}
b61d15d5 CH	311	if (sbi->s_version == MINIX_V3)
	312	((minix3_dirent *)de)->inode = 0;
	313	else
	314	de->inode = 0;
f556e776	315	dir_commit_chunk(page, pos, len);
f7f43858	316	inode->i_mtime = inode_set_ctime_current(inode);
1da177e4	317	mark_inode_dirty(inode);
f556e776	318	return minix_handle_dirsync(inode);
1da177e4 LT	319	}
	320
	321	int minix_make_empty(struct inode inode, struct inode dir)
	322	{
f4e420dc	323	struct page *page = grab_cache_page(inode->i_mapping, 0);
939b00df	324	struct minix_sb_info *sbi = minix_sb(inode->i_sb);
1da177e4 LT	325	char *kaddr;
	326	int err;
	327
	328	if (!page)
	329	return -ENOMEM;
f4e420dc	330	err = minix_prepare_chunk(page, 0, 2 * sbi->s_dirsize);
1da177e4 LT	331	if (err) {
	332	unlock_page(page);
	333	goto fail;
	334	}
	335
27a6d5c7	336	kaddr = kmap_atomic(page);
09cbfeaf	337	memset(kaddr, 0, PAGE_SIZE);
1da177e4	338
939b00df AB	339	if (sbi->s_version == MINIX_V3) {
	340	minix3_dirent de3 = (minix3_dirent )kaddr;
	341
	342	de3->inode = inode->i_ino;
	343	strcpy(de3->name, ".");
	344	de3 = minix_next_entry(de3, sbi);
	345	de3->inode = dir->i_ino;
	346	strcpy(de3->name, "..");
	347	} else {
	348	minix_dirent de = (minix_dirent )kaddr;
	349
	350	de->inode = inode->i_ino;
	351	strcpy(de->name, ".");
	352	de = minix_next_entry(de, sbi);
	353	de->inode = dir->i_ino;
	354	strcpy(de->name, "..");
	355	}
27a6d5c7	356	kunmap_atomic(kaddr);
1da177e4	357
f556e776 CH	358	dir_commit_chunk(page, 0, 2 * sbi->s_dirsize);
f556e776 CH	359	err = minix_handle_dirsync(inode);
1da177e4	360	fail:
09cbfeaf	361	put_page(page);
1da177e4 LT	362	return err;
	363	}
	364
	365	/*
	366	* routine to check that the specified directory is empty (for rmdir)
	367	*/
	368	int minix_empty_dir(struct inode * inode)
	369	{
	370	struct page *page = NULL;
	371	unsigned long i, npages = dir_pages(inode);
	372	struct minix_sb_info *sbi = minix_sb(inode->i_sb);
939b00df AB	373	char *name;
939b00df AB	374	__u32 inumber;
1da177e4 LT	375
1da177e4 LT	376	for (i = 0; i < npages; i++) {
939b00df	377	char p, kaddr, *limit;
1da177e4	378
939b00df	379	page = dir_get_page(inode, i);
1da177e4 LT	380	if (IS_ERR(page))
	381	continue;
	382
	383	kaddr = (char *)page_address(page);
939b00df AB	384	limit = kaddr + minix_last_byte(inode, i) - sbi->s_dirsize;
	385	for (p = kaddr; p <= limit; p = minix_next_entry(p, sbi)) {
	386	if (sbi->s_version == MINIX_V3) {
	387	minix3_dirent de3 = (minix3_dirent )p;
	388	name = de3->name;
	389	inumber = de3->inode;
	390	} else {
	391	minix_dirent de = (minix_dirent )p;
	392	name = de->name;
	393	inumber = de->inode;
	394	}
1da177e4	395
939b00df	396	if (inumber != 0) {
1da177e4	397	/* check for . and .. */
939b00df	398	if (name[0] != '.')
1da177e4	399	goto not_empty;
939b00df AB	400	if (!name[1]) {
939b00df AB	401	if (inumber != inode->i_ino)
1da177e4	402	goto not_empty;
939b00df	403	} else if (name[1] != '.')
1da177e4	404	goto not_empty;
939b00df	405	else if (name[2])
1da177e4 LT	406	goto not_empty;
1da177e4 LT	407	}
1da177e4 LT	408	}
	409	dir_put_page(page);
	410	}
	411	return 1;
	412
	413	not_empty:
	414	dir_put_page(page);
	415	return 0;
	416	}
	417
	418	/* Releases the page */
2d1a9d59 CH	419	int minix_set_link(struct minix_dir_entry de, struct page page,
2d1a9d59 CH	420	struct inode *inode)
1da177e4	421	{
f4e420dc	422	struct inode *dir = page->mapping->host;
1da177e4	423	struct minix_sb_info *sbi = minix_sb(dir->i_sb);
4a66af9e NP	424	loff_t pos = page_offset(page) +
4a66af9e NP	425	(char )de-(char)page_address(page);
1da177e4 LT	426	int err;
	427
	428	lock_page(page);
f4e420dc	429	err = minix_prepare_chunk(page, pos, sbi->s_dirsize);
2d1a9d59	430	if (err) {
1da177e4	431	unlock_page(page);
2d1a9d59	432	return err;
1da177e4	433	}
2d1a9d59 CH	434	if (sbi->s_version == MINIX_V3)
	435	((minix3_dirent *)de)->inode = inode->i_ino;
	436	else
	437	de->inode = inode->i_ino;
f556e776	438	dir_commit_chunk(page, pos, sbi->s_dirsize);
f7f43858	439	dir->i_mtime = inode_set_ctime_current(dir);
1da177e4	440	mark_inode_dirty(dir);
f556e776	441	return minix_handle_dirsync(dir);
1da177e4 LT	442	}
	443
	444	struct minix_dir_entry * minix_dotdot (struct inode dir, struct page *p)
	445	{
	446	struct page *page = dir_get_page(dir, 0);
	447	struct minix_sb_info *sbi = minix_sb(dir->i_sb);
	448	struct minix_dir_entry *de = NULL;
	449
	450	if (!IS_ERR(page)) {
	451	de = minix_next_entry(page_address(page), sbi);
	452	*p = page;
	453	}
	454	return de;
	455	}
	456
	457	ino_t minix_inode_by_name(struct dentry *dentry)
	458	{
	459	struct page *page;
	460	struct minix_dir_entry *de = minix_find_entry(dentry, &page);
	461	ino_t res = 0;
	462
	463	if (de) {
9f6c1333 DG	464	struct address_space *mapping = page->mapping;
	465	struct inode *inode = mapping->host;
	466	struct minix_sb_info *sbi = minix_sb(inode->i_sb);
	467
	468	if (sbi->s_version == MINIX_V3)
	469	res = ((minix3_dirent *) de)->inode;
	470	else
	471	res = de->inode;
1da177e4 LT	472	dir_put_page(page);
	473	}
	474	return res;
	475	}