[net-next-2.6.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 *, void *, filldir_t);

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

static inline void dir_put_page(struct page *page)
{
	kunmap(page);
	page_cache_release(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_CACHE_SIZE;

	if (page_nr == (inode->i_size >> PAGE_CACHE_SHIFT))
		last_byte = inode->i_size & (PAGE_CACHE_SIZE - 1);
	return last_byte;
}

static inline unsigned long dir_pages(struct inode *inode)
{
	return (inode->i_size+PAGE_CACHE_SIZE-1)>>PAGE_CACHE_SHIFT;
}

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, 1);
	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 * filp, void * dirent, filldir_t filldir)
{
	unsigned long pos = filp->f_pos;
	struct inode *inode = filp->f_path.dentry->d_inode;
	struct super_block *sb = inode->i_sb;
	unsigned offset = pos & ~PAGE_CACHE_MASK;
	unsigned long n = pos >> PAGE_CACHE_SHIFT;
	unsigned long npages = dir_pages(inode);
	struct minix_sb_info *sbi = minix_sb(sb);
	unsigned chunk_size = sbi->s_dirsize;
	char *name;
	__u32 inumber;

	pos = (pos + chunk_size-1) & ~(chunk_size-1);
	if (pos >= inode->i_size)
		goto done;

	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)) {
			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) {
				int over;

				unsigned l = strnlen(name, sbi->s_namelen);
				offset = p - kaddr;
				over = filldir(dirent, name, l,
					(n << PAGE_CACHE_SHIFT) | offset,
					inumber, DT_UNKNOWN);
				if (over) {
					dir_put_page(page);
					goto done;
				}
			}
		}
		dir_put_page(page);
	}

done:
	filp->f_pos = (n << PAGE_CACHE_SHIFT) | offset;
	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 = dentry->d_parent->d_inode;
	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 = dentry->d_parent->d_inode;
	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_CACHE_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_write_begin(NULL, page->mapping, pos, sbi->s_dirsize,
					AOP_FLAG_UNINTERRUPTIBLE, &page, NULL);
	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_SEC;
	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 address_space *mapping = page->mapping;
	struct inode *inode = (struct inode*)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_write_begin(NULL, mapping, pos, len,
					AOP_FLAG_UNINTERRUPTIBLE, &page, NULL);
	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_SEC;
	mark_inode_dirty(inode);
	return err;
}

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

	if (!page)
		return -ENOMEM;
	err = __minix_write_begin(NULL, mapping, 0, 2 * sbi->s_dirsize,
					AOP_FLAG_UNINTERRUPTIBLE, &page, NULL);
	if (err) {
		unlock_page(page);
		goto fail;
	}

	kaddr = kmap_atomic(page, KM_USER0);
	memset(kaddr, 0, PAGE_CACHE_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, KM_USER0);

	err = dir_commit_chunk(page, 0, 2 * sbi->s_dirsize);
fail:
	page_cache_release(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 address_space *mapping = page->mapping;
	struct inode *dir = 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_write_begin(NULL, mapping, pos, sbi->s_dirsize,
					AOP_FLAG_UNINTERRUPTIBLE, &page, NULL);
	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_SEC;
	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
	1	/*
	2	* linux/fs/minix/dir.c
	3	*
	4	* Copyright (C) 1991, 1992 Linus Torvalds
	5	*
	6	* minix directory handling functions
	7	*
	8	* Updated to filesystem version 3 by Daniel Aragones
	9	*/
	10
	11	#include "minix.h"
	12	#include <linux/buffer_head.h>
	13	#include <linux/highmem.h>
	14	#include <linux/swap.h>
	15
	16	typedef struct minix_dir_entry minix_dirent;
	17	typedef struct minix3_dir_entry minix3_dirent;
	18
	19	static int minix_readdir(struct file , void , filldir_t);
	20
	21	const struct file_operations minix_dir_operations = {
	22	.llseek = generic_file_llseek,
	23	.read = generic_read_dir,
	24	.readdir = minix_readdir,
	25	.fsync = generic_file_fsync,
	26	};
	27
	28	static inline void dir_put_page(struct page *page)
	29	{
	30	kunmap(page);
	31	page_cache_release(page);
	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	{
	41	unsigned last_byte = PAGE_CACHE_SIZE;
	42
	43	if (page_nr == (inode->i_size >> PAGE_CACHE_SHIFT))
	44	last_byte = inode->i_size & (PAGE_CACHE_SIZE - 1);
	45	return last_byte;
	46	}
	47
	48	static inline unsigned long dir_pages(struct inode *inode)
	49	{
	50	return (inode->i_size+PAGE_CACHE_SIZE-1)>>PAGE_CACHE_SHIFT;
	51	}
	52
	53	static int dir_commit_chunk(struct page *page, loff_t pos, unsigned len)
	54	{
	55	struct address_space *mapping = page->mapping;
	56	struct inode *dir = mapping->host;
	57	int err = 0;
	58	block_write_end(NULL, mapping, pos, len, len, page, NULL);
	59
	60	if (pos+len > dir->i_size) {
	61	i_size_write(dir, pos+len);
	62	mark_inode_dirty(dir);
	63	}
	64	if (IS_DIRSYNC(dir))
	65	err = write_one_page(page, 1);
	66	else
	67	unlock_page(page);
	68	return err;
	69	}
	70
	71	static struct page * dir_get_page(struct inode *dir, unsigned long n)
	72	{
	73	struct address_space *mapping = dir->i_mapping;
	74	struct page *page = read_mapping_page(mapping, n, NULL);
	75	if (!IS_ERR(page))
	76	kmap(page);
	77	return page;
	78	}
	79
	80	static inline void minix_next_entry(void de, struct minix_sb_info *sbi)
	81	{
	82	return (void)((char)de + sbi->s_dirsize);
	83	}
	84
	85	static int minix_readdir(struct file * filp, void * dirent, filldir_t filldir)
	86	{
	87	unsigned long pos = filp->f_pos;
	88	struct inode *inode = filp->f_path.dentry->d_inode;
	89	struct super_block *sb = inode->i_sb;
	90	unsigned offset = pos & ~PAGE_CACHE_MASK;
	91	unsigned long n = pos >> PAGE_CACHE_SHIFT;
	92	unsigned long npages = dir_pages(inode);
	93	struct minix_sb_info *sbi = minix_sb(sb);
	94	unsigned chunk_size = sbi->s_dirsize;
	95	char *name;
	96	__u32 inumber;
	97
	98	pos = (pos + chunk_size-1) & ~(chunk_size-1);
	99	if (pos >= inode->i_size)
	100	goto done;
	101
	102	for ( ; n < npages; n++, offset = 0) {
	103	char p, kaddr, *limit;
	104	struct page *page = dir_get_page(inode, n);
	105
	106	if (IS_ERR(page))
	107	continue;
	108	kaddr = (char *)page_address(page);
	109	p = kaddr+offset;
	110	limit = kaddr + minix_last_byte(inode, n) - chunk_size;
	111	for ( ; p <= limit; p = minix_next_entry(p, sbi)) {
	112	if (sbi->s_version == MINIX_V3) {
	113	minix3_dirent de3 = (minix3_dirent )p;
	114	name = de3->name;
	115	inumber = de3->inode;
	116	} else {
	117	minix_dirent de = (minix_dirent )p;
	118	name = de->name;
	119	inumber = de->inode;
	120	}
	121	if (inumber) {
	122	int over;
	123
	124	unsigned l = strnlen(name, sbi->s_namelen);
	125	offset = p - kaddr;
	126	over = filldir(dirent, name, l,
	127	(n << PAGE_CACHE_SHIFT) \| offset,
	128	inumber, DT_UNKNOWN);
	129	if (over) {
	130	dir_put_page(page);
	131	goto done;
	132	}
	133	}
	134	}
	135	dir_put_page(page);
	136	}
	137
	138	done:
	139	filp->f_pos = (n << PAGE_CACHE_SHIFT) \| offset;
	140	return 0;
	141	}
	142
	143	static inline int namecompare(int len, int maxlen,
	144	const char * name, const char * buffer)
	145	{
	146	if (len < maxlen && buffer[len])
	147	return 0;
	148	return !memcmp(name, buffer, len);
	149	}
	150
	151	/*
	152	* minix_find_entry()
	153	*
	154	* finds an entry in the specified directory with the wanted name. It
	155	* returns the cache buffer in which the entry was found, and the entry
	156	* itself (as a parameter - res_dir). It does NOT read the inode of the
	157	* entry - you'll have to do that yourself if you want to.
	158	*/
	159	minix_dirent minix_find_entry(struct dentry dentry, struct page **res_page)
	160	{
	161	const char * name = dentry->d_name.name;
	162	int namelen = dentry->d_name.len;
	163	struct inode * dir = dentry->d_parent->d_inode;
	164	struct super_block * sb = dir->i_sb;
	165	struct minix_sb_info * sbi = minix_sb(sb);
	166	unsigned long n;
	167	unsigned long npages = dir_pages(dir);
	168	struct page *page = NULL;
	169	char *p;
	170
	171	char *namx;
	172	__u32 inumber;
	173	*res_page = NULL;
	174
	175	for (n = 0; n < npages; n++) {
	176	char kaddr, limit;
	177
	178	page = dir_get_page(dir, n);
	179	if (IS_ERR(page))
	180	continue;
	181
	182	kaddr = (char*)page_address(page);
	183	limit = kaddr + minix_last_byte(dir, n) - sbi->s_dirsize;
	184	for (p = kaddr; p <= limit; p = minix_next_entry(p, sbi)) {
	185	if (sbi->s_version == MINIX_V3) {
	186	minix3_dirent de3 = (minix3_dirent )p;
	187	namx = de3->name;
	188	inumber = de3->inode;
	189	} else {
	190	minix_dirent de = (minix_dirent )p;
	191	namx = de->name;
	192	inumber = de->inode;
	193	}
	194	if (!inumber)
	195	continue;
	196	if (namecompare(namelen, sbi->s_namelen, name, namx))
	197	goto found;
	198	}
	199	dir_put_page(page);
	200	}
	201	return NULL;
	202
	203	found:
	204	*res_page = page;
	205	return (minix_dirent *)p;
	206	}
	207
	208	int minix_add_link(struct dentry dentry, struct inode inode)
	209	{
	210	struct inode *dir = dentry->d_parent->d_inode;
	211	const char * name = dentry->d_name.name;
	212	int namelen = dentry->d_name.len;
	213	struct super_block * sb = dir->i_sb;
	214	struct minix_sb_info * sbi = minix_sb(sb);
	215	struct page *page = NULL;
	216	unsigned long npages = dir_pages(dir);
	217	unsigned long n;
	218	char kaddr, p;
	219	minix_dirent *de;
	220	minix3_dirent *de3;
	221	loff_t pos;
	222	int err;
	223	char *namx = NULL;
	224	__u32 inumber;
	225
	226	/*
	227	* We take care of directory expansion in the same loop
	228	* This code plays outside i_size, so it locks the page
	229	* to protect that region.
	230	*/
	231	for (n = 0; n <= npages; n++) {
	232	char limit, dir_end;
	233
	234	page = dir_get_page(dir, n);
	235	err = PTR_ERR(page);
	236	if (IS_ERR(page))
	237	goto out;
	238	lock_page(page);
	239	kaddr = (char*)page_address(page);
	240	dir_end = kaddr + minix_last_byte(dir, n);
	241	limit = kaddr + PAGE_CACHE_SIZE - sbi->s_dirsize;
	242	for (p = kaddr; p <= limit; p = minix_next_entry(p, sbi)) {
	243	de = (minix_dirent *)p;
	244	de3 = (minix3_dirent *)p;
	245	if (sbi->s_version == MINIX_V3) {
	246	namx = de3->name;
	247	inumber = de3->inode;
	248	} else {
	249	namx = de->name;
	250	inumber = de->inode;
	251	}
	252	if (p == dir_end) {
	253	/* We hit i_size */
	254	if (sbi->s_version == MINIX_V3)
	255	de3->inode = 0;
	256	else
	257	de->inode = 0;
	258	goto got_it;
	259	}
	260	if (!inumber)
	261	goto got_it;
	262	err = -EEXIST;
	263	if (namecompare(namelen, sbi->s_namelen, name, namx))
	264	goto out_unlock;
	265	}
	266	unlock_page(page);
	267	dir_put_page(page);
	268	}
	269	BUG();
	270	return -EINVAL;
	271
	272	got_it:
	273	pos = page_offset(page) + p - (char *)page_address(page);
	274	err = __minix_write_begin(NULL, page->mapping, pos, sbi->s_dirsize,
	275	AOP_FLAG_UNINTERRUPTIBLE, &page, NULL);
	276	if (err)
	277	goto out_unlock;
	278	memcpy (namx, name, namelen);
	279	if (sbi->s_version == MINIX_V3) {
	280	memset (namx + namelen, 0, sbi->s_dirsize - namelen - 4);
	281	de3->inode = inode->i_ino;
	282	} else {
	283	memset (namx + namelen, 0, sbi->s_dirsize - namelen - 2);
	284	de->inode = inode->i_ino;
	285	}
	286	err = dir_commit_chunk(page, pos, sbi->s_dirsize);
	287	dir->i_mtime = dir->i_ctime = CURRENT_TIME_SEC;
	288	mark_inode_dirty(dir);
	289	out_put:
	290	dir_put_page(page);
	291	out:
	292	return err;
	293	out_unlock:
	294	unlock_page(page);
	295	goto out_put;
	296	}
	297
	298	int minix_delete_entry(struct minix_dir_entry de, struct page page)
	299	{
	300	struct address_space *mapping = page->mapping;
	301	struct inode inode = (struct inode)mapping->host;
	302	char *kaddr = page_address(page);
	303	loff_t pos = page_offset(page) + (char*)de - kaddr;
	304	struct minix_sb_info *sbi = minix_sb(inode->i_sb);
	305	unsigned len = sbi->s_dirsize;
	306	int err;
	307
	308	lock_page(page);
	309	err = __minix_write_begin(NULL, mapping, pos, len,
	310	AOP_FLAG_UNINTERRUPTIBLE, &page, NULL);
	311	if (err == 0) {
	312	if (sbi->s_version == MINIX_V3)
	313	((minix3_dirent *) de)->inode = 0;
	314	else
	315	de->inode = 0;
	316	err = dir_commit_chunk(page, pos, len);
	317	} else {
	318	unlock_page(page);
	319	}
	320	dir_put_page(page);
	321	inode->i_ctime = inode->i_mtime = CURRENT_TIME_SEC;
	322	mark_inode_dirty(inode);
	323	return err;
	324	}
	325
	326	int minix_make_empty(struct inode inode, struct inode dir)
	327	{
	328	struct address_space *mapping = inode->i_mapping;
	329	struct page *page = grab_cache_page(mapping, 0);
	330	struct minix_sb_info *sbi = minix_sb(inode->i_sb);
	331	char *kaddr;
	332	int err;
	333
	334	if (!page)
	335	return -ENOMEM;
	336	err = __minix_write_begin(NULL, mapping, 0, 2 * sbi->s_dirsize,
	337	AOP_FLAG_UNINTERRUPTIBLE, &page, NULL);
	338	if (err) {
	339	unlock_page(page);
	340	goto fail;
	341	}
	342
	343	kaddr = kmap_atomic(page, KM_USER0);
	344	memset(kaddr, 0, PAGE_CACHE_SIZE);
	345
	346	if (sbi->s_version == MINIX_V3) {
	347	minix3_dirent de3 = (minix3_dirent )kaddr;
	348
	349	de3->inode = inode->i_ino;
	350	strcpy(de3->name, ".");
	351	de3 = minix_next_entry(de3, sbi);
	352	de3->inode = dir->i_ino;
	353	strcpy(de3->name, "..");
	354	} else {
	355	minix_dirent de = (minix_dirent )kaddr;
	356
	357	de->inode = inode->i_ino;
	358	strcpy(de->name, ".");
	359	de = minix_next_entry(de, sbi);
	360	de->inode = dir->i_ino;
	361	strcpy(de->name, "..");
	362	}
	363	kunmap_atomic(kaddr, KM_USER0);
	364
	365	err = dir_commit_chunk(page, 0, 2 * sbi->s_dirsize);
	366	fail:
	367	page_cache_release(page);
	368	return err;
	369	}
	370
	371	/*
	372	* routine to check that the specified directory is empty (for rmdir)
	373	*/
	374	int minix_empty_dir(struct inode * inode)
	375	{
	376	struct page *page = NULL;
	377	unsigned long i, npages = dir_pages(inode);
	378	struct minix_sb_info *sbi = minix_sb(inode->i_sb);
	379	char *name;
	380	__u32 inumber;
	381
	382	for (i = 0; i < npages; i++) {
	383	char p, kaddr, *limit;
	384
	385	page = dir_get_page(inode, i);
	386	if (IS_ERR(page))
	387	continue;
	388
	389	kaddr = (char *)page_address(page);
	390	limit = kaddr + minix_last_byte(inode, i) - sbi->s_dirsize;
	391	for (p = kaddr; p <= limit; p = minix_next_entry(p, sbi)) {
	392	if (sbi->s_version == MINIX_V3) {
	393	minix3_dirent de3 = (minix3_dirent )p;
	394	name = de3->name;
	395	inumber = de3->inode;
	396	} else {
	397	minix_dirent de = (minix_dirent )p;
	398	name = de->name;
	399	inumber = de->inode;
	400	}
	401
	402	if (inumber != 0) {
	403	/* check for . and .. */
	404	if (name[0] != '.')
	405	goto not_empty;
	406	if (!name[1]) {
	407	if (inumber != inode->i_ino)
	408	goto not_empty;
	409	} else if (name[1] != '.')
	410	goto not_empty;
	411	else if (name[2])
	412	goto not_empty;
	413	}
	414	}
	415	dir_put_page(page);
	416	}
	417	return 1;
	418
	419	not_empty:
	420	dir_put_page(page);
	421	return 0;
	422	}
	423
	424	/* Releases the page */
	425	void minix_set_link(struct minix_dir_entry de, struct page page,
	426	struct inode *inode)
	427	{
	428	struct address_space *mapping = page->mapping;
	429	struct inode *dir = mapping->host;
	430	struct minix_sb_info *sbi = minix_sb(dir->i_sb);
	431	loff_t pos = page_offset(page) +
	432	(char )de-(char)page_address(page);
	433	int err;
	434
	435	lock_page(page);
	436
	437	err = __minix_write_begin(NULL, mapping, pos, sbi->s_dirsize,
	438	AOP_FLAG_UNINTERRUPTIBLE, &page, NULL);
	439	if (err == 0) {
	440	if (sbi->s_version == MINIX_V3)
	441	((minix3_dirent *) de)->inode = inode->i_ino;
	442	else
	443	de->inode = inode->i_ino;
	444	err = dir_commit_chunk(page, pos, sbi->s_dirsize);
	445	} else {
	446	unlock_page(page);
	447	}
	448	dir_put_page(page);
	449	dir->i_mtime = dir->i_ctime = CURRENT_TIME_SEC;
	450	mark_inode_dirty(dir);
	451	}
	452
	453	struct minix_dir_entry * minix_dotdot (struct inode dir, struct page *p)
	454	{
	455	struct page *page = dir_get_page(dir, 0);
	456	struct minix_sb_info *sbi = minix_sb(dir->i_sb);
	457	struct minix_dir_entry *de = NULL;
	458
	459	if (!IS_ERR(page)) {
	460	de = minix_next_entry(page_address(page), sbi);
	461	*p = page;
	462	}
	463	return de;
	464	}
	465
	466	ino_t minix_inode_by_name(struct dentry *dentry)
	467	{
	468	struct page *page;
	469	struct minix_dir_entry *de = minix_find_entry(dentry, &page);
	470	ino_t res = 0;
	471
	472	if (de) {
	473	struct address_space *mapping = page->mapping;
	474	struct inode *inode = mapping->host;
	475	struct minix_sb_info *sbi = minix_sb(inode->i_sb);
	476
	477	if (sbi->s_version == MINIX_V3)
	478	res = ((minix3_dirent *) de)->inode;
	479	else
	480	res = de->inode;
	481	dir_put_page(page);
	482	}
	483	return res;
	484	}