[linux-2.6-block.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		= simple_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);
		if (!PageUptodate(page))
			goto fail;
	}
	return page;

fail:
	dir_put_page(page);
	return ERR_PTR(-EIO);
}

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
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 LT	18
	19	static int minix_readdir(struct file , void , filldir_t);
	20
4b6f5d20	21	const struct file_operations minix_dir_operations = {
cc46759a	22	.llseek = generic_file_llseek,
1da177e4 LT	23	.read = generic_read_dir,
1da177e4 LT	24	.readdir = minix_readdir,
0d7916d7	25	.fsync = simple_fsync,
1da177e4 LT	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
4a66af9e	53	static int dir_commit_chunk(struct page *page, loff_t pos, unsigned len)
1da177e4	54	{
4a66af9e NP	55	struct address_space *mapping = page->mapping;
4a66af9e NP	56	struct inode *dir = mapping->host;
1da177e4	57	int err = 0;
4a66af9e NP	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	}
1da177e4 LT	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;
090d2b18	74	struct page *page = read_mapping_page(mapping, n, NULL);
1da177e4	75	if (!IS_ERR(page)) {
1da177e4 LT	76	kmap(page);
	77	if (!PageUptodate(page))
	78	goto fail;
	79	}
	80	return page;
	81
	82	fail:
	83	dir_put_page(page);
	84	return ERR_PTR(-EIO);
	85	}
	86
	87	static inline void minix_next_entry(void de, struct minix_sb_info *sbi)
	88	{
	89	return (void)((char)de + sbi->s_dirsize);
	90	}
	91
	92	static int minix_readdir(struct file * filp, void * dirent, filldir_t filldir)
	93	{
	94	unsigned long pos = filp->f_pos;
dcf258ae	95	struct inode *inode = filp->f_path.dentry->d_inode;
1da177e4 LT	96	struct super_block *sb = inode->i_sb;
	97	unsigned offset = pos & ~PAGE_CACHE_MASK;
	98	unsigned long n = pos >> PAGE_CACHE_SHIFT;
	99	unsigned long npages = dir_pages(inode);
	100	struct minix_sb_info *sbi = minix_sb(sb);
	101	unsigned chunk_size = sbi->s_dirsize;
939b00df AB	102	char *name;
939b00df AB	103	__u32 inumber;
1da177e4	104
1da177e4 LT	105	pos = (pos + chunk_size-1) & ~(chunk_size-1);
	106	if (pos >= inode->i_size)
	107	goto done;
	108
	109	for ( ; n < npages; n++, offset = 0) {
	110	char p, kaddr, *limit;
	111	struct page *page = dir_get_page(inode, n);
	112
	113	if (IS_ERR(page))
	114	continue;
	115	kaddr = (char *)page_address(page);
	116	p = kaddr+offset;
	117	limit = kaddr + minix_last_byte(inode, n) - chunk_size;
939b00df AB	118	for ( ; p <= limit; p = minix_next_entry(p, sbi)) {
	119	if (sbi->s_version == MINIX_V3) {
	120	minix3_dirent de3 = (minix3_dirent )p;
	121	name = de3->name;
	122	inumber = de3->inode;
	123	} else {
	124	minix_dirent de = (minix_dirent )p;
	125	name = de->name;
	126	inumber = de->inode;
	127	}
	128	if (inumber) {
1da177e4	129	int over;
1da177e4	130
939b00df	131	unsigned l = strnlen(name, sbi->s_namelen);
1da177e4	132	offset = p - kaddr;
939b00df AB	133	over = filldir(dirent, name, l,
	134	(n << PAGE_CACHE_SHIFT) \| offset,
	135	inumber, DT_UNKNOWN);
1da177e4 LT	136	if (over) {
	137	dir_put_page(page);
	138	goto done;
	139	}
	140	}
	141	}
	142	dir_put_page(page);
	143	}
	144
	145	done:
	146	filp->f_pos = (n << PAGE_CACHE_SHIFT) \| offset;
1da177e4 LT	147	return 0;
	148	}
	149
	150	static inline int namecompare(int len, int maxlen,
	151	const char * name, const char * buffer)
	152	{
	153	if (len < maxlen && buffer[len])
	154	return 0;
	155	return !memcmp(name, buffer, len);
	156	}
	157
	158	/*
	159	* minix_find_entry()
	160	*
	161	* finds an entry in the specified directory with the wanted name. It
	162	* returns the cache buffer in which the entry was found, and the entry
	163	* itself (as a parameter - res_dir). It does NOT read the inode of the
	164	* entry - you'll have to do that yourself if you want to.
	165	*/
	166	minix_dirent minix_find_entry(struct dentry dentry, struct page **res_page)
	167	{
	168	const char * name = dentry->d_name.name;
	169	int namelen = dentry->d_name.len;
	170	struct inode * dir = dentry->d_parent->d_inode;
	171	struct super_block * sb = dir->i_sb;
	172	struct minix_sb_info * sbi = minix_sb(sb);
	173	unsigned long n;
	174	unsigned long npages = dir_pages(dir);
	175	struct page *page = NULL;
939b00df	176	char *p;
1da177e4	177
939b00df AB	178	char *namx;
939b00df AB	179	__u32 inumber;
1da177e4 LT	180	*res_page = NULL;
	181
	182	for (n = 0; n < npages; n++) {
939b00df AB	183	char kaddr, limit;
939b00df AB	184
1da177e4 LT	185	page = dir_get_page(dir, n);
	186	if (IS_ERR(page))
	187	continue;
	188
	189	kaddr = (char*)page_address(page);
939b00df AB	190	limit = kaddr + minix_last_byte(dir, n) - sbi->s_dirsize;
	191	for (p = kaddr; p <= limit; p = minix_next_entry(p, sbi)) {
	192	if (sbi->s_version == MINIX_V3) {
	193	minix3_dirent de3 = (minix3_dirent )p;
	194	namx = de3->name;
	195	inumber = de3->inode;
	196	} else {
	197	minix_dirent de = (minix_dirent )p;
	198	namx = de->name;
	199	inumber = de->inode;
	200	}
	201	if (!inumber)
1da177e4	202	continue;
939b00df	203	if (namecompare(namelen, sbi->s_namelen, name, namx))
1da177e4 LT	204	goto found;
	205	}
	206	dir_put_page(page);
	207	}
	208	return NULL;
	209
	210	found:
	211	*res_page = page;
939b00df	212	return (minix_dirent *)p;
1da177e4 LT	213	}
	214
	215	int minix_add_link(struct dentry dentry, struct inode inode)
	216	{
	217	struct inode *dir = dentry->d_parent->d_inode;
	218	const char * name = dentry->d_name.name;
	219	int namelen = dentry->d_name.len;
	220	struct super_block * sb = dir->i_sb;
	221	struct minix_sb_info * sbi = minix_sb(sb);
	222	struct page *page = NULL;
1da177e4 LT	223	unsigned long npages = dir_pages(dir);
1da177e4 LT	224	unsigned long n;
939b00df AB	225	char kaddr, p;
	226	minix_dirent *de;
	227	minix3_dirent *de3;
4a66af9e	228	loff_t pos;
1da177e4	229	int err;
939b00df AB	230	char *namx = NULL;
939b00df AB	231	__u32 inumber;
1da177e4 LT	232
	233	/*
	234	* We take care of directory expansion in the same loop
	235	* This code plays outside i_size, so it locks the page
	236	* to protect that region.
	237	*/
	238	for (n = 0; n <= npages; n++) {
939b00df	239	char limit, dir_end;
1da177e4 LT	240
	241	page = dir_get_page(dir, n);
	242	err = PTR_ERR(page);
	243	if (IS_ERR(page))
	244	goto out;
	245	lock_page(page);
	246	kaddr = (char*)page_address(page);
	247	dir_end = kaddr + minix_last_byte(dir, n);
939b00df AB	248	limit = kaddr + PAGE_CACHE_SIZE - sbi->s_dirsize;
	249	for (p = kaddr; p <= limit; p = minix_next_entry(p, sbi)) {
	250	de = (minix_dirent *)p;
	251	de3 = (minix3_dirent *)p;
	252	if (sbi->s_version == MINIX_V3) {
	253	namx = de3->name;
	254	inumber = de3->inode;
	255	} else {
	256	namx = de->name;
	257	inumber = de->inode;
	258	}
	259	if (p == dir_end) {
1da177e4	260	/* We hit i_size */
939b00df AB	261	if (sbi->s_version == MINIX_V3)
	262	de3->inode = 0;
	263	else
	264	de->inode = 0;
1da177e4 LT	265	goto got_it;
1da177e4 LT	266	}
939b00df	267	if (!inumber)
1da177e4 LT	268	goto got_it;
1da177e4 LT	269	err = -EEXIST;
939b00df	270	if (namecompare(namelen, sbi->s_namelen, name, namx))
1da177e4	271	goto out_unlock;
1da177e4 LT	272	}
	273	unlock_page(page);
	274	dir_put_page(page);
	275	}
	276	BUG();
	277	return -EINVAL;
	278
	279	got_it:
d6b54841	280	pos = page_offset(page) + p - (char *)page_address(page);
4a66af9e NP	281	err = __minix_write_begin(NULL, page->mapping, pos, sbi->s_dirsize,
4a66af9e NP	282	AOP_FLAG_UNINTERRUPTIBLE, &page, NULL);
1da177e4 LT	283	if (err)
1da177e4 LT	284	goto out_unlock;
939b00df AB	285	memcpy (namx, name, namelen);
	286	if (sbi->s_version == MINIX_V3) {
	287	memset (namx + namelen, 0, sbi->s_dirsize - namelen - 4);
	288	de3->inode = inode->i_ino;
	289	} else {
	290	memset (namx + namelen, 0, sbi->s_dirsize - namelen - 2);
	291	de->inode = inode->i_ino;
	292	}
4a66af9e	293	err = dir_commit_chunk(page, pos, sbi->s_dirsize);
1da177e4 LT	294	dir->i_mtime = dir->i_ctime = CURRENT_TIME_SEC;
	295	mark_inode_dirty(dir);
	296	out_put:
	297	dir_put_page(page);
	298	out:
	299	return err;
	300	out_unlock:
	301	unlock_page(page);
	302	goto out_put;
	303	}
	304
	305	int minix_delete_entry(struct minix_dir_entry de, struct page page)
	306	{
	307	struct address_space *mapping = page->mapping;
	308	struct inode inode = (struct inode)mapping->host;
	309	char *kaddr = page_address(page);
4a66af9e	310	loff_t pos = page_offset(page) + (char*)de - kaddr;
9f6c1333 DG	311	struct minix_sb_info *sbi = minix_sb(inode->i_sb);
9f6c1333 DG	312	unsigned len = sbi->s_dirsize;
1da177e4 LT	313	int err;
	314
	315	lock_page(page);
4a66af9e NP	316	err = __minix_write_begin(NULL, mapping, pos, len,
4a66af9e NP	317	AOP_FLAG_UNINTERRUPTIBLE, &page, NULL);
1da177e4	318	if (err == 0) {
9f6c1333 DG	319	if (sbi->s_version == MINIX_V3)
	320	((minix3_dirent *) de)->inode = 0;
	321	else
	322	de->inode = 0;
4a66af9e	323	err = dir_commit_chunk(page, pos, len);
1da177e4 LT	324	} else {
	325	unlock_page(page);
	326	}
	327	dir_put_page(page);
	328	inode->i_ctime = inode->i_mtime = CURRENT_TIME_SEC;
	329	mark_inode_dirty(inode);
	330	return err;
	331	}
	332
	333	int minix_make_empty(struct inode inode, struct inode dir)
	334	{
	335	struct address_space *mapping = inode->i_mapping;
	336	struct page *page = grab_cache_page(mapping, 0);
939b00df	337	struct minix_sb_info *sbi = minix_sb(inode->i_sb);
1da177e4 LT	338	char *kaddr;
	339	int err;
	340
	341	if (!page)
	342	return -ENOMEM;
4a66af9e NP	343	err = __minix_write_begin(NULL, mapping, 0, 2 * sbi->s_dirsize,
4a66af9e NP	344	AOP_FLAG_UNINTERRUPTIBLE, &page, NULL);
1da177e4 LT	345	if (err) {
	346	unlock_page(page);
	347	goto fail;
	348	}
	349
	350	kaddr = kmap_atomic(page, KM_USER0);
	351	memset(kaddr, 0, PAGE_CACHE_SIZE);
	352
939b00df AB	353	if (sbi->s_version == MINIX_V3) {
	354	minix3_dirent de3 = (minix3_dirent )kaddr;
	355
	356	de3->inode = inode->i_ino;
	357	strcpy(de3->name, ".");
	358	de3 = minix_next_entry(de3, sbi);
	359	de3->inode = dir->i_ino;
	360	strcpy(de3->name, "..");
	361	} else {
	362	minix_dirent de = (minix_dirent )kaddr;
	363
	364	de->inode = inode->i_ino;
	365	strcpy(de->name, ".");
	366	de = minix_next_entry(de, sbi);
	367	de->inode = dir->i_ino;
	368	strcpy(de->name, "..");
	369	}
1da177e4 LT	370	kunmap_atomic(kaddr, KM_USER0);
	371
	372	err = dir_commit_chunk(page, 0, 2 * sbi->s_dirsize);
	373	fail:
	374	page_cache_release(page);
	375	return err;
	376	}
	377
	378	/*
	379	* routine to check that the specified directory is empty (for rmdir)
	380	*/
	381	int minix_empty_dir(struct inode * inode)
	382	{
	383	struct page *page = NULL;
	384	unsigned long i, npages = dir_pages(inode);
	385	struct minix_sb_info *sbi = minix_sb(inode->i_sb);
939b00df AB	386	char *name;
939b00df AB	387	__u32 inumber;
1da177e4 LT	388
1da177e4 LT	389	for (i = 0; i < npages; i++) {
939b00df	390	char p, kaddr, *limit;
1da177e4	391
939b00df	392	page = dir_get_page(inode, i);
1da177e4 LT	393	if (IS_ERR(page))
	394	continue;
	395
	396	kaddr = (char *)page_address(page);
939b00df AB	397	limit = kaddr + minix_last_byte(inode, i) - sbi->s_dirsize;
	398	for (p = kaddr; p <= limit; p = minix_next_entry(p, sbi)) {
	399	if (sbi->s_version == MINIX_V3) {
	400	minix3_dirent de3 = (minix3_dirent )p;
	401	name = de3->name;
	402	inumber = de3->inode;
	403	} else {
	404	minix_dirent de = (minix_dirent )p;
	405	name = de->name;
	406	inumber = de->inode;
	407	}
1da177e4	408
939b00df	409	if (inumber != 0) {
1da177e4	410	/* check for . and .. */
939b00df	411	if (name[0] != '.')
1da177e4	412	goto not_empty;
939b00df AB	413	if (!name[1]) {
939b00df AB	414	if (inumber != inode->i_ino)
1da177e4	415	goto not_empty;
939b00df	416	} else if (name[1] != '.')
1da177e4	417	goto not_empty;
939b00df	418	else if (name[2])
1da177e4 LT	419	goto not_empty;
1da177e4 LT	420	}
1da177e4 LT	421	}
	422	dir_put_page(page);
	423	}
	424	return 1;
	425
	426	not_empty:
	427	dir_put_page(page);
	428	return 0;
	429	}
	430
	431	/* Releases the page */
	432	void minix_set_link(struct minix_dir_entry de, struct page page,
	433	struct inode *inode)
	434	{
4a66af9e NP	435	struct address_space *mapping = page->mapping;
4a66af9e NP	436	struct inode *dir = mapping->host;
1da177e4	437	struct minix_sb_info *sbi = minix_sb(dir->i_sb);
4a66af9e NP	438	loff_t pos = page_offset(page) +
4a66af9e NP	439	(char )de-(char)page_address(page);
1da177e4 LT	440	int err;
	441
	442	lock_page(page);
4a66af9e NP	443
	444	err = __minix_write_begin(NULL, mapping, pos, sbi->s_dirsize,
	445	AOP_FLAG_UNINTERRUPTIBLE, &page, NULL);
1da177e4	446	if (err == 0) {
9f6c1333 DG	447	if (sbi->s_version == MINIX_V3)
	448	((minix3_dirent *) de)->inode = inode->i_ino;
	449	else
	450	de->inode = inode->i_ino;
4a66af9e	451	err = dir_commit_chunk(page, pos, sbi->s_dirsize);
1da177e4 LT	452	} else {
	453	unlock_page(page);
	454	}
	455	dir_put_page(page);
	456	dir->i_mtime = dir->i_ctime = CURRENT_TIME_SEC;
	457	mark_inode_dirty(dir);
	458	}
	459
	460	struct minix_dir_entry * minix_dotdot (struct inode dir, struct page *p)
	461	{
	462	struct page *page = dir_get_page(dir, 0);
	463	struct minix_sb_info *sbi = minix_sb(dir->i_sb);
	464	struct minix_dir_entry *de = NULL;
	465
	466	if (!IS_ERR(page)) {
	467	de = minix_next_entry(page_address(page), sbi);
	468	*p = page;
	469	}
	470	return de;
	471	}
	472
	473	ino_t minix_inode_by_name(struct dentry *dentry)
	474	{
	475	struct page *page;
	476	struct minix_dir_entry *de = minix_find_entry(dentry, &page);
	477	ino_t res = 0;
	478
	479	if (de) {
9f6c1333 DG	480	struct address_space *mapping = page->mapping;
	481	struct inode *inode = mapping->host;
	482	struct minix_sb_info *sbi = minix_sb(inode->i_sb);
	483
	484	if (sbi->s_version == MINIX_V3)
	485	res = ((minix3_dirent *) de)->inode;
	486	else
	487	res = de->inode;
1da177e4 LT	488	dir_put_page(page);
	489	}
	490	return res;
	491	}