[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 *, struct dir_context *);

const struct file_operations minix_dir_operations = {
	.llseek		= generic_file_llseek,
	.read		= generic_read_dir,
	.iterate	= 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 *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_CACHE_MASK;
	n = pos >> PAGE_CACHE_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 = 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	18
80886298	19	static int minix_readdir(struct file , struct dir_context );
1da177e4	20
4b6f5d20	21	const struct file_operations minix_dir_operations = {
cc46759a	22	.llseek = generic_file_llseek,
1da177e4	23	.read = generic_read_dir,
80886298	24	.iterate = 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
80886298	85	static int minix_readdir(struct file file, struct dir_context ctx)
1da177e4	86	{
80886298	87	struct inode *inode = file_inode(file);
1da177e4	88	struct super_block *sb = inode->i_sb;
1da177e4 LT	89	struct minix_sb_info *sbi = minix_sb(sb);
1da177e4 LT	90	unsigned chunk_size = sbi->s_dirsize;
80886298 AV	91	unsigned long npages = dir_pages(inode);
	92	unsigned long pos = ctx->pos;
	93	unsigned offset;
	94	unsigned long n;
1da177e4	95
642b704c	96	ctx->pos = pos = ALIGN(pos, chunk_size);
1da177e4	97	if (pos >= inode->i_size)
80886298 AV	98	return 0;
	99
	100	offset = pos & ~PAGE_CACHE_MASK;
	101	n = pos >> PAGE_CACHE_SHIFT;
1da177e4 LT	102
	103	for ( ; n < npages; n++, offset = 0) {
	104	char p, kaddr, *limit;
	105	struct page *page = dir_get_page(inode, n);
	106
	107	if (IS_ERR(page))
	108	continue;
	109	kaddr = (char *)page_address(page);
	110	p = kaddr+offset;
	111	limit = kaddr + minix_last_byte(inode, n) - chunk_size;
939b00df	112	for ( ; p <= limit; p = minix_next_entry(p, sbi)) {
80886298 AV	113	const char *name;
80886298 AV	114	__u32 inumber;
939b00df AB	115	if (sbi->s_version == MINIX_V3) {
	116	minix3_dirent de3 = (minix3_dirent )p;
	117	name = de3->name;
	118	inumber = de3->inode;
	119	} else {
	120	minix_dirent de = (minix_dirent )p;
	121	name = de->name;
	122	inumber = de->inode;
	123	}
	124	if (inumber) {
939b00df	125	unsigned l = strnlen(name, sbi->s_namelen);
80886298 AV	126	if (!dir_emit(ctx, name, l,
80886298 AV	127	inumber, DT_UNKNOWN)) {
1da177e4	128	dir_put_page(page);
80886298	129	return 0;
1da177e4 LT	130	}
1da177e4 LT	131	}
80886298	132	ctx->pos += chunk_size;
1da177e4 LT	133	}
	134	dir_put_page(page);
	135	}
1da177e4 LT	136	return 0;
	137	}
	138
	139	static inline int namecompare(int len, int maxlen,
	140	const char * name, const char * buffer)
	141	{
	142	if (len < maxlen && buffer[len])
	143	return 0;
	144	return !memcmp(name, buffer, len);
	145	}
	146
	147	/*
	148	* minix_find_entry()
	149	*
	150	* finds an entry in the specified directory with the wanted name. It
	151	* returns the cache buffer in which the entry was found, and the entry
	152	* itself (as a parameter - res_dir). It does NOT read the inode of the
	153	* entry - you'll have to do that yourself if you want to.
	154	*/
	155	minix_dirent minix_find_entry(struct dentry dentry, struct page **res_page)
	156	{
	157	const char * name = dentry->d_name.name;
	158	int namelen = dentry->d_name.len;
	159	struct inode * dir = dentry->d_parent->d_inode;
	160	struct super_block * sb = dir->i_sb;
	161	struct minix_sb_info * sbi = minix_sb(sb);
	162	unsigned long n;
	163	unsigned long npages = dir_pages(dir);
	164	struct page *page = NULL;
939b00df	165	char *p;
1da177e4	166
939b00df AB	167	char *namx;
939b00df AB	168	__u32 inumber;
1da177e4 LT	169	*res_page = NULL;
	170
	171	for (n = 0; n < npages; n++) {
939b00df AB	172	char kaddr, limit;
939b00df AB	173
1da177e4 LT	174	page = dir_get_page(dir, n);
	175	if (IS_ERR(page))
	176	continue;
	177
	178	kaddr = (char*)page_address(page);
939b00df AB	179	limit = kaddr + minix_last_byte(dir, n) - sbi->s_dirsize;
	180	for (p = kaddr; p <= limit; p = minix_next_entry(p, sbi)) {
	181	if (sbi->s_version == MINIX_V3) {
	182	minix3_dirent de3 = (minix3_dirent )p;
	183	namx = de3->name;
	184	inumber = de3->inode;
	185	} else {
	186	minix_dirent de = (minix_dirent )p;
	187	namx = de->name;
	188	inumber = de->inode;
	189	}
	190	if (!inumber)
1da177e4	191	continue;
939b00df	192	if (namecompare(namelen, sbi->s_namelen, name, namx))
1da177e4 LT	193	goto found;
	194	}
	195	dir_put_page(page);
	196	}
	197	return NULL;
	198
	199	found:
	200	*res_page = page;
939b00df	201	return (minix_dirent *)p;
1da177e4 LT	202	}
	203
	204	int minix_add_link(struct dentry dentry, struct inode inode)
	205	{
	206	struct inode *dir = dentry->d_parent->d_inode;
	207	const char * name = dentry->d_name.name;
	208	int namelen = dentry->d_name.len;
	209	struct super_block * sb = dir->i_sb;
	210	struct minix_sb_info * sbi = minix_sb(sb);
	211	struct page *page = NULL;
1da177e4 LT	212	unsigned long npages = dir_pages(dir);
1da177e4 LT	213	unsigned long n;
939b00df AB	214	char kaddr, p;
	215	minix_dirent *de;
	216	minix3_dirent *de3;
4a66af9e	217	loff_t pos;
1da177e4	218	int err;
939b00df AB	219	char *namx = NULL;
939b00df AB	220	__u32 inumber;
1da177e4 LT	221
	222	/*
	223	* We take care of directory expansion in the same loop
	224	* This code plays outside i_size, so it locks the page
	225	* to protect that region.
	226	*/
	227	for (n = 0; n <= npages; n++) {
939b00df	228	char limit, dir_end;
1da177e4 LT	229
	230	page = dir_get_page(dir, n);
	231	err = PTR_ERR(page);
	232	if (IS_ERR(page))
	233	goto out;
	234	lock_page(page);
	235	kaddr = (char*)page_address(page);
	236	dir_end = kaddr + minix_last_byte(dir, n);
939b00df AB	237	limit = kaddr + PAGE_CACHE_SIZE - sbi->s_dirsize;
	238	for (p = kaddr; p <= limit; p = minix_next_entry(p, sbi)) {
	239	de = (minix_dirent *)p;
	240	de3 = (minix3_dirent *)p;
	241	if (sbi->s_version == MINIX_V3) {
	242	namx = de3->name;
	243	inumber = de3->inode;
	244	} else {
	245	namx = de->name;
	246	inumber = de->inode;
	247	}
	248	if (p == dir_end) {
1da177e4	249	/* We hit i_size */
939b00df AB	250	if (sbi->s_version == MINIX_V3)
	251	de3->inode = 0;
	252	else
	253	de->inode = 0;
1da177e4 LT	254	goto got_it;
1da177e4 LT	255	}
939b00df	256	if (!inumber)
1da177e4 LT	257	goto got_it;
1da177e4 LT	258	err = -EEXIST;
939b00df	259	if (namecompare(namelen, sbi->s_namelen, name, namx))
1da177e4	260	goto out_unlock;
1da177e4 LT	261	}
	262	unlock_page(page);
	263	dir_put_page(page);
	264	}
	265	BUG();
	266	return -EINVAL;
	267
	268	got_it:
d6b54841	269	pos = page_offset(page) + p - (char *)page_address(page);
f4e420dc	270	err = minix_prepare_chunk(page, pos, sbi->s_dirsize);
1da177e4 LT	271	if (err)
1da177e4 LT	272	goto out_unlock;
939b00df AB	273	memcpy (namx, name, namelen);
	274	if (sbi->s_version == MINIX_V3) {
	275	memset (namx + namelen, 0, sbi->s_dirsize - namelen - 4);
	276	de3->inode = inode->i_ino;
	277	} else {
	278	memset (namx + namelen, 0, sbi->s_dirsize - namelen - 2);
	279	de->inode = inode->i_ino;
	280	}
4a66af9e	281	err = dir_commit_chunk(page, pos, sbi->s_dirsize);
1da177e4 LT	282	dir->i_mtime = dir->i_ctime = CURRENT_TIME_SEC;
	283	mark_inode_dirty(dir);
	284	out_put:
	285	dir_put_page(page);
	286	out:
	287	return err;
	288	out_unlock:
	289	unlock_page(page);
	290	goto out_put;
	291	}
	292
	293	int minix_delete_entry(struct minix_dir_entry de, struct page page)
	294	{
f4e420dc	295	struct inode *inode = page->mapping->host;
1da177e4	296	char *kaddr = page_address(page);
4a66af9e	297	loff_t pos = page_offset(page) + (char*)de - kaddr;
9f6c1333 DG	298	struct minix_sb_info *sbi = minix_sb(inode->i_sb);
9f6c1333 DG	299	unsigned len = sbi->s_dirsize;
1da177e4 LT	300	int err;
	301
	302	lock_page(page);
f4e420dc	303	err = minix_prepare_chunk(page, pos, len);
1da177e4	304	if (err == 0) {
9f6c1333 DG	305	if (sbi->s_version == MINIX_V3)
	306	((minix3_dirent *) de)->inode = 0;
	307	else
	308	de->inode = 0;
4a66af9e	309	err = dir_commit_chunk(page, pos, len);
1da177e4 LT	310	} else {
	311	unlock_page(page);
	312	}
	313	dir_put_page(page);
	314	inode->i_ctime = inode->i_mtime = CURRENT_TIME_SEC;
	315	mark_inode_dirty(inode);
	316	return err;
	317	}
	318
	319	int minix_make_empty(struct inode inode, struct inode dir)
	320	{
f4e420dc	321	struct page *page = grab_cache_page(inode->i_mapping, 0);
939b00df	322	struct minix_sb_info *sbi = minix_sb(inode->i_sb);
1da177e4 LT	323	char *kaddr;
	324	int err;
	325
	326	if (!page)
	327	return -ENOMEM;
f4e420dc	328	err = minix_prepare_chunk(page, 0, 2 * sbi->s_dirsize);
1da177e4 LT	329	if (err) {
	330	unlock_page(page);
	331	goto fail;
	332	}
	333
27a6d5c7	334	kaddr = kmap_atomic(page);
1da177e4 LT	335	memset(kaddr, 0, PAGE_CACHE_SIZE);
1da177e4 LT	336
939b00df AB	337	if (sbi->s_version == MINIX_V3) {
	338	minix3_dirent de3 = (minix3_dirent )kaddr;
	339
	340	de3->inode = inode->i_ino;
	341	strcpy(de3->name, ".");
	342	de3 = minix_next_entry(de3, sbi);
	343	de3->inode = dir->i_ino;
	344	strcpy(de3->name, "..");
	345	} else {
	346	minix_dirent de = (minix_dirent )kaddr;
	347
	348	de->inode = inode->i_ino;
	349	strcpy(de->name, ".");
	350	de = minix_next_entry(de, sbi);
	351	de->inode = dir->i_ino;
	352	strcpy(de->name, "..");
	353	}
27a6d5c7	354	kunmap_atomic(kaddr);
1da177e4 LT	355
	356	err = dir_commit_chunk(page, 0, 2 * sbi->s_dirsize);
	357	fail:
	358	page_cache_release(page);
	359	return err;
	360	}
	361
	362	/*
	363	* routine to check that the specified directory is empty (for rmdir)
	364	*/
	365	int minix_empty_dir(struct inode * inode)
	366	{
	367	struct page *page = NULL;
	368	unsigned long i, npages = dir_pages(inode);
	369	struct minix_sb_info *sbi = minix_sb(inode->i_sb);
939b00df AB	370	char *name;
939b00df AB	371	__u32 inumber;
1da177e4 LT	372
1da177e4 LT	373	for (i = 0; i < npages; i++) {
939b00df	374	char p, kaddr, *limit;
1da177e4	375
939b00df	376	page = dir_get_page(inode, i);
1da177e4 LT	377	if (IS_ERR(page))
	378	continue;
	379
	380	kaddr = (char *)page_address(page);
939b00df AB	381	limit = kaddr + minix_last_byte(inode, i) - sbi->s_dirsize;
	382	for (p = kaddr; p <= limit; p = minix_next_entry(p, sbi)) {
	383	if (sbi->s_version == MINIX_V3) {
	384	minix3_dirent de3 = (minix3_dirent )p;
	385	name = de3->name;
	386	inumber = de3->inode;
	387	} else {
	388	minix_dirent de = (minix_dirent )p;
	389	name = de->name;
	390	inumber = de->inode;
	391	}
1da177e4	392
939b00df	393	if (inumber != 0) {
1da177e4	394	/* check for . and .. */
939b00df	395	if (name[0] != '.')
1da177e4	396	goto not_empty;
939b00df AB	397	if (!name[1]) {
939b00df AB	398	if (inumber != inode->i_ino)
1da177e4	399	goto not_empty;
939b00df	400	} else if (name[1] != '.')
1da177e4	401	goto not_empty;
939b00df	402	else if (name[2])
1da177e4 LT	403	goto not_empty;
1da177e4 LT	404	}
1da177e4 LT	405	}
	406	dir_put_page(page);
	407	}
	408	return 1;
	409
	410	not_empty:
	411	dir_put_page(page);
	412	return 0;
	413	}
	414
	415	/* Releases the page */
	416	void minix_set_link(struct minix_dir_entry de, struct page page,
	417	struct inode *inode)
	418	{
f4e420dc	419	struct inode *dir = page->mapping->host;
1da177e4	420	struct minix_sb_info *sbi = minix_sb(dir->i_sb);
4a66af9e NP	421	loff_t pos = page_offset(page) +
4a66af9e NP	422	(char )de-(char)page_address(page);
1da177e4 LT	423	int err;
	424
	425	lock_page(page);
4a66af9e	426
f4e420dc	427	err = minix_prepare_chunk(page, pos, sbi->s_dirsize);
1da177e4	428	if (err == 0) {
9f6c1333 DG	429	if (sbi->s_version == MINIX_V3)
	430	((minix3_dirent *) de)->inode = inode->i_ino;
	431	else
	432	de->inode = inode->i_ino;
4a66af9e	433	err = dir_commit_chunk(page, pos, sbi->s_dirsize);
1da177e4 LT	434	} else {
	435	unlock_page(page);
	436	}
	437	dir_put_page(page);
	438	dir->i_mtime = dir->i_ctime = CURRENT_TIME_SEC;
	439	mark_inode_dirty(dir);
	440	}
	441
	442	struct minix_dir_entry * minix_dotdot (struct inode dir, struct page *p)
	443	{
	444	struct page *page = dir_get_page(dir, 0);
	445	struct minix_sb_info *sbi = minix_sb(dir->i_sb);
	446	struct minix_dir_entry *de = NULL;
	447
	448	if (!IS_ERR(page)) {
	449	de = minix_next_entry(page_address(page), sbi);
	450	*p = page;
	451	}
	452	return de;
	453	}
	454
	455	ino_t minix_inode_by_name(struct dentry *dentry)
	456	{
	457	struct page *page;
	458	struct minix_dir_entry *de = minix_find_entry(dentry, &page);
	459	ino_t res = 0;
	460
	461	if (de) {
9f6c1333 DG	462	struct address_space *mapping = page->mapping;
	463	struct inode *inode = mapping->host;
	464	struct minix_sb_info *sbi = minix_sb(inode->i_sb);
	465
	466	if (sbi->s_version == MINIX_V3)
	467	res = ((minix3_dirent *) de)->inode;
	468	else
	469	res = de->inode;
1da177e4 LT	470	dir_put_page(page);
	471	}
	472	return res;
	473	}