[linux.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_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_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 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_SEC;
	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_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);

	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 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_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,
1b061d92	25	.fsync = generic_file_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);
49837a80	75	if (!IS_ERR(page))
1da177e4	76	kmap(page);
1da177e4	77	return page;
1da177e4 LT	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;
dcf258ae	88	struct inode *inode = filp->f_path.dentry->d_inode;
1da177e4 LT	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;
939b00df AB	95	char *name;
939b00df AB	96	__u32 inumber;
1da177e4	97
1da177e4 LT	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;
939b00df AB	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) {
1da177e4	122	int over;
1da177e4	123
939b00df	124	unsigned l = strnlen(name, sbi->s_namelen);
1da177e4	125	offset = p - kaddr;
939b00df AB	126	over = filldir(dirent, name, l,
	127	(n << PAGE_CACHE_SHIFT) \| offset,
	128	inumber, DT_UNKNOWN);
1da177e4 LT	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;
1da177e4 LT	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;
939b00df	169	char *p;
1da177e4	170
939b00df AB	171	char *namx;
939b00df AB	172	__u32 inumber;
1da177e4 LT	173	*res_page = NULL;
	174
	175	for (n = 0; n < npages; n++) {
939b00df AB	176	char kaddr, limit;
939b00df AB	177
1da177e4 LT	178	page = dir_get_page(dir, n);
	179	if (IS_ERR(page))
	180	continue;
	181
	182	kaddr = (char*)page_address(page);
939b00df AB	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)
1da177e4	195	continue;
939b00df	196	if (namecompare(namelen, sbi->s_namelen, name, namx))
1da177e4 LT	197	goto found;
	198	}
	199	dir_put_page(page);
	200	}
	201	return NULL;
	202
	203	found:
	204	*res_page = page;
939b00df	205	return (minix_dirent *)p;
1da177e4 LT	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;
1da177e4 LT	216	unsigned long npages = dir_pages(dir);
1da177e4 LT	217	unsigned long n;
939b00df AB	218	char kaddr, p;
	219	minix_dirent *de;
	220	minix3_dirent *de3;
4a66af9e	221	loff_t pos;
1da177e4	222	int err;
939b00df AB	223	char *namx = NULL;
939b00df AB	224	__u32 inumber;
1da177e4 LT	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++) {
939b00df	232	char limit, dir_end;
1da177e4 LT	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);
939b00df AB	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) {
1da177e4	253	/* We hit i_size */
939b00df AB	254	if (sbi->s_version == MINIX_V3)
	255	de3->inode = 0;
	256	else
	257	de->inode = 0;
1da177e4 LT	258	goto got_it;
1da177e4 LT	259	}
939b00df	260	if (!inumber)
1da177e4 LT	261	goto got_it;
1da177e4 LT	262	err = -EEXIST;
939b00df	263	if (namecompare(namelen, sbi->s_namelen, name, namx))
1da177e4	264	goto out_unlock;
1da177e4 LT	265	}
	266	unlock_page(page);
	267	dir_put_page(page);
	268	}
	269	BUG();
	270	return -EINVAL;
	271
	272	got_it:
d6b54841	273	pos = page_offset(page) + p - (char *)page_address(page);
f4e420dc	274	err = minix_prepare_chunk(page, pos, sbi->s_dirsize);
1da177e4 LT	275	if (err)
1da177e4 LT	276	goto out_unlock;
939b00df AB	277	memcpy (namx, name, namelen);
	278	if (sbi->s_version == MINIX_V3) {
	279	memset (namx + namelen, 0, sbi->s_dirsize - namelen - 4);
	280	de3->inode = inode->i_ino;
	281	} else {
	282	memset (namx + namelen, 0, sbi->s_dirsize - namelen - 2);
	283	de->inode = inode->i_ino;
	284	}
4a66af9e	285	err = dir_commit_chunk(page, pos, sbi->s_dirsize);
1da177e4 LT	286	dir->i_mtime = dir->i_ctime = CURRENT_TIME_SEC;
	287	mark_inode_dirty(dir);
	288	out_put:
	289	dir_put_page(page);
	290	out:
	291	return err;
	292	out_unlock:
	293	unlock_page(page);
	294	goto out_put;
	295	}
	296
	297	int minix_delete_entry(struct minix_dir_entry de, struct page page)
	298	{
f4e420dc	299	struct inode *inode = page->mapping->host;
1da177e4	300	char *kaddr = page_address(page);
4a66af9e	301	loff_t pos = page_offset(page) + (char*)de - kaddr;
9f6c1333 DG	302	struct minix_sb_info *sbi = minix_sb(inode->i_sb);
9f6c1333 DG	303	unsigned len = sbi->s_dirsize;
1da177e4 LT	304	int err;
	305
	306	lock_page(page);
f4e420dc	307	err = minix_prepare_chunk(page, pos, len);
1da177e4	308	if (err == 0) {
9f6c1333 DG	309	if (sbi->s_version == MINIX_V3)
	310	((minix3_dirent *) de)->inode = 0;
	311	else
	312	de->inode = 0;
4a66af9e	313	err = dir_commit_chunk(page, pos, len);
1da177e4 LT	314	} else {
	315	unlock_page(page);
	316	}
	317	dir_put_page(page);
	318	inode->i_ctime = inode->i_mtime = CURRENT_TIME_SEC;
	319	mark_inode_dirty(inode);
	320	return err;
	321	}
	322
	323	int minix_make_empty(struct inode inode, struct inode dir)
	324	{
f4e420dc	325	struct page *page = grab_cache_page(inode->i_mapping, 0);
939b00df	326	struct minix_sb_info *sbi = minix_sb(inode->i_sb);
1da177e4 LT	327	char *kaddr;
	328	int err;
	329
	330	if (!page)
	331	return -ENOMEM;
f4e420dc	332	err = minix_prepare_chunk(page, 0, 2 * sbi->s_dirsize);
1da177e4 LT	333	if (err) {
	334	unlock_page(page);
	335	goto fail;
	336	}
	337
27a6d5c7	338	kaddr = kmap_atomic(page);
1da177e4 LT	339	memset(kaddr, 0, PAGE_CACHE_SIZE);
1da177e4 LT	340
939b00df AB	341	if (sbi->s_version == MINIX_V3) {
	342	minix3_dirent de3 = (minix3_dirent )kaddr;
	343
	344	de3->inode = inode->i_ino;
	345	strcpy(de3->name, ".");
	346	de3 = minix_next_entry(de3, sbi);
	347	de3->inode = dir->i_ino;
	348	strcpy(de3->name, "..");
	349	} else {
	350	minix_dirent de = (minix_dirent )kaddr;
	351
	352	de->inode = inode->i_ino;
	353	strcpy(de->name, ".");
	354	de = minix_next_entry(de, sbi);
	355	de->inode = dir->i_ino;
	356	strcpy(de->name, "..");
	357	}
27a6d5c7	358	kunmap_atomic(kaddr);
1da177e4 LT	359
	360	err = dir_commit_chunk(page, 0, 2 * sbi->s_dirsize);
	361	fail:
	362	page_cache_release(page);
	363	return err;
	364	}
	365
	366	/*
	367	* routine to check that the specified directory is empty (for rmdir)
	368	*/
	369	int minix_empty_dir(struct inode * inode)
	370	{
	371	struct page *page = NULL;
	372	unsigned long i, npages = dir_pages(inode);
	373	struct minix_sb_info *sbi = minix_sb(inode->i_sb);
939b00df AB	374	char *name;
939b00df AB	375	__u32 inumber;
1da177e4 LT	376
1da177e4 LT	377	for (i = 0; i < npages; i++) {
939b00df	378	char p, kaddr, *limit;
1da177e4	379
939b00df	380	page = dir_get_page(inode, i);
1da177e4 LT	381	if (IS_ERR(page))
	382	continue;
	383
	384	kaddr = (char *)page_address(page);
939b00df AB	385	limit = kaddr + minix_last_byte(inode, i) - sbi->s_dirsize;
	386	for (p = kaddr; p <= limit; p = minix_next_entry(p, sbi)) {
	387	if (sbi->s_version == MINIX_V3) {
	388	minix3_dirent de3 = (minix3_dirent )p;
	389	name = de3->name;
	390	inumber = de3->inode;
	391	} else {
	392	minix_dirent de = (minix_dirent )p;
	393	name = de->name;
	394	inumber = de->inode;
	395	}
1da177e4	396
939b00df	397	if (inumber != 0) {
1da177e4	398	/* check for . and .. */
939b00df	399	if (name[0] != '.')
1da177e4	400	goto not_empty;
939b00df AB	401	if (!name[1]) {
939b00df AB	402	if (inumber != inode->i_ino)
1da177e4	403	goto not_empty;
939b00df	404	} else if (name[1] != '.')
1da177e4	405	goto not_empty;
939b00df	406	else if (name[2])
1da177e4 LT	407	goto not_empty;
1da177e4 LT	408	}
1da177e4 LT	409	}
	410	dir_put_page(page);
	411	}
	412	return 1;
	413
	414	not_empty:
	415	dir_put_page(page);
	416	return 0;
	417	}
	418
	419	/* Releases the page */
	420	void minix_set_link(struct minix_dir_entry de, struct page page,
	421	struct inode *inode)
	422	{
f4e420dc	423	struct inode *dir = page->mapping->host;
1da177e4	424	struct minix_sb_info *sbi = minix_sb(dir->i_sb);
4a66af9e NP	425	loff_t pos = page_offset(page) +
4a66af9e NP	426	(char )de-(char)page_address(page);
1da177e4 LT	427	int err;
	428
	429	lock_page(page);
4a66af9e	430
f4e420dc	431	err = minix_prepare_chunk(page, pos, sbi->s_dirsize);
1da177e4	432	if (err == 0) {
9f6c1333 DG	433	if (sbi->s_version == MINIX_V3)
	434	((minix3_dirent *) de)->inode = inode->i_ino;
	435	else
	436	de->inode = inode->i_ino;
4a66af9e	437	err = dir_commit_chunk(page, pos, sbi->s_dirsize);
1da177e4 LT	438	} else {
	439	unlock_page(page);
	440	}
	441	dir_put_page(page);
	442	dir->i_mtime = dir->i_ctime = CURRENT_TIME_SEC;
	443	mark_inode_dirty(dir);
	444	}
	445
	446	struct minix_dir_entry * minix_dotdot (struct inode dir, struct page *p)
	447	{
	448	struct page *page = dir_get_page(dir, 0);
	449	struct minix_sb_info *sbi = minix_sb(dir->i_sb);
	450	struct minix_dir_entry *de = NULL;
	451
	452	if (!IS_ERR(page)) {
	453	de = minix_next_entry(page_address(page), sbi);
	454	*p = page;
	455	}
	456	return de;
	457	}
	458
	459	ino_t minix_inode_by_name(struct dentry *dentry)
	460	{
	461	struct page *page;
	462	struct minix_dir_entry *de = minix_find_entry(dentry, &page);
	463	ino_t res = 0;
	464
	465	if (de) {
9f6c1333 DG	466	struct address_space *mapping = page->mapping;
	467	struct inode *inode = mapping->host;
	468	struct minix_sb_info *sbi = minix_sb(inode->i_sb);
	469
	470	if (sbi->s_version == MINIX_V3)
	471	res = ((minix3_dirent *) de)->inode;
	472	else
	473	res = de->inode;
1da177e4 LT	474	dir_put_page(page);
	475	}
	476	return res;
	477	}