[linux.git] / fs / minix / dir.c

// SPDX-License-Identifier: GPL-2.0
/*
 *  linux/fs/minix/dir.c
 *
 *  Copyright (C) 1991, 1992 Linus Torvalds
 *
 *  minix directory handling functions
 *
 *  Updated to filesystem version 3 by Daniel Aragones
 */

#include "minix.h"
#include <linux/buffer_head.h>
#include <linux/highmem.h>
#include <linux/swap.h>

typedef struct minix_dir_entry minix_dirent;
typedef struct minix3_dir_entry minix3_dirent;

static int minix_readdir(struct file *, struct dir_context *);

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

/*
 * Return the offset into page `page_nr' of the last valid
 * byte in that page, plus one.
 */
static unsigned
minix_last_byte(struct inode *inode, unsigned long page_nr)
{
	unsigned last_byte = PAGE_SIZE;

	if (page_nr == (inode->i_size >> PAGE_SHIFT))
		last_byte = inode->i_size & (PAGE_SIZE - 1);
	return last_byte;
}

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

	block_write_end(NULL, mapping, pos, len, len, page, NULL);

	if (pos+len > dir->i_size) {
		i_size_write(dir, pos+len);
		mark_inode_dirty(dir);
	}
	unlock_page(page);
}

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

	err = filemap_write_and_wait(dir->i_mapping);
	if (!err)
		err = sync_inode_metadata(dir, 1);
	return err;
}

static void *dir_get_page(struct inode *dir, unsigned long n, struct page **p)
{
	struct address_space *mapping = dir->i_mapping;
	struct page *page = read_mapping_page(mapping, n, NULL);
	if (IS_ERR(page))
		return ERR_CAST(page);
	*p = page;
	return kmap_local_page(page);
}

static inline void *minix_next_entry(void *de, struct minix_sb_info *sbi)
{
	return (void*)((char*)de + sbi->s_dirsize);
}

static int minix_readdir(struct file *file, struct dir_context *ctx)
{
	struct inode *inode = file_inode(file);
	struct super_block *sb = inode->i_sb;
	struct minix_sb_info *sbi = minix_sb(sb);
	unsigned chunk_size = sbi->s_dirsize;
	unsigned long npages = dir_pages(inode);
	unsigned long pos = ctx->pos;
	unsigned offset;
	unsigned long n;

	ctx->pos = pos = ALIGN(pos, chunk_size);
	if (pos >= inode->i_size)
		return 0;

	offset = pos & ~PAGE_MASK;
	n = pos >> PAGE_SHIFT;

	for ( ; n < npages; n++, offset = 0) {
		char *p, *kaddr, *limit;
		struct page *page;

		kaddr = dir_get_page(inode, n, &page);
		if (IS_ERR(kaddr))
			continue;
		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)) {
					unmap_and_put_page(page, p);
					return 0;
				}
			}
			ctx->pos += chunk_size;
		}
		unmap_and_put_page(page, kaddr);
	}
	return 0;
}

static inline int namecompare(int len, int maxlen,
	const char * name, const char * buffer)
{
	if (len < maxlen && buffer[len])
		return 0;
	return !memcmp(name, buffer, len);
}

/*
 *	minix_find_entry()
 *
 * finds an entry in the specified directory with the wanted name. It
 * returns the cache buffer in which the entry was found, and the entry
 * itself (as a parameter - res_dir). It does NOT read the inode of the
 * entry - you'll have to do that yourself if you want to.
 */
minix_dirent *minix_find_entry(struct dentry *dentry, struct page **res_page)
{
	const char * name = dentry->d_name.name;
	int namelen = dentry->d_name.len;
	struct inode * dir = d_inode(dentry->d_parent);
	struct super_block * sb = dir->i_sb;
	struct minix_sb_info * sbi = minix_sb(sb);
	unsigned long n;
	unsigned long npages = dir_pages(dir);
	struct page *page = NULL;
	char *p;

	char *namx;
	__u32 inumber;
	*res_page = NULL;

	for (n = 0; n < npages; n++) {
		char *kaddr, *limit;

		kaddr = dir_get_page(dir, n, &page);
		if (IS_ERR(kaddr))
			continue;

		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;
		}
		unmap_and_put_page(page, kaddr);
	}
	return NULL;

found:
	*res_page = page;
	return (minix_dirent *)p;
}

int minix_add_link(struct dentry *dentry, struct inode *inode)
{
	struct inode *dir = d_inode(dentry->d_parent);
	const char * name = dentry->d_name.name;
	int namelen = dentry->d_name.len;
	struct super_block * sb = dir->i_sb;
	struct minix_sb_info * sbi = minix_sb(sb);
	struct page *page = NULL;
	unsigned long npages = dir_pages(dir);
	unsigned long n;
	char *kaddr, *p;
	minix_dirent *de;
	minix3_dirent *de3;
	loff_t pos;
	int err;
	char *namx = NULL;
	__u32 inumber;

	/*
	 * We take care of directory expansion in the same loop
	 * This code plays outside i_size, so it locks the page
	 * to protect that region.
	 */
	for (n = 0; n <= npages; n++) {
		char *limit, *dir_end;

		kaddr = dir_get_page(dir, n, &page);
		if (IS_ERR(kaddr))
			return PTR_ERR(kaddr);
		lock_page(page);
		dir_end = kaddr + minix_last_byte(dir, n);
		limit = kaddr + PAGE_SIZE - sbi->s_dirsize;
		for (p = kaddr; p <= limit; p = minix_next_entry(p, sbi)) {
			de = (minix_dirent *)p;
			de3 = (minix3_dirent *)p;
			if (sbi->s_version == MINIX_V3) {
				namx = de3->name;
				inumber = de3->inode;
		 	} else {
  				namx = de->name;
				inumber = de->inode;
			}
			if (p == dir_end) {
				/* We hit i_size */
				if (sbi->s_version == MINIX_V3)
					de3->inode = 0;
		 		else
					de->inode = 0;
				goto got_it;
			}
			if (!inumber)
				goto got_it;
			err = -EEXIST;
			if (namecompare(namelen, sbi->s_namelen, name, namx))
				goto out_unlock;
		}
		unlock_page(page);
		unmap_and_put_page(page, kaddr);
	}
	BUG();
	return -EINVAL;

got_it:
	pos = page_offset(page) + offset_in_page(p);
	err = minix_prepare_chunk(page, pos, sbi->s_dirsize);
	if (err)
		goto out_unlock;
	memcpy (namx, name, namelen);
	if (sbi->s_version == MINIX_V3) {
		memset (namx + namelen, 0, sbi->s_dirsize - namelen - 4);
		de3->inode = inode->i_ino;
	} else {
		memset (namx + namelen, 0, sbi->s_dirsize - namelen - 2);
		de->inode = inode->i_ino;
	}
	dir_commit_chunk(page, pos, sbi->s_dirsize);
	inode_set_mtime_to_ts(dir, inode_set_ctime_current(dir));
	mark_inode_dirty(dir);
	err = minix_handle_dirsync(dir);
out_put:
	unmap_and_put_page(page, kaddr);
	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;
	loff_t pos = page_offset(page) + offset_in_page(de);
	struct minix_sb_info *sbi = minix_sb(inode->i_sb);
	unsigned len = sbi->s_dirsize;
	int err;

	lock_page(page);
	err = minix_prepare_chunk(page, pos, len);
	if (err) {
		unlock_page(page);
		return err;
	}
	if (sbi->s_version == MINIX_V3)
		((minix3_dirent *)de)->inode = 0;
	else
		de->inode = 0;
	dir_commit_chunk(page, pos, len);
	inode_set_mtime_to_ts(inode, inode_set_ctime_current(inode));
	mark_inode_dirty(inode);
	return minix_handle_dirsync(inode);
}

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

	if (!page)
		return -ENOMEM;
	err = minix_prepare_chunk(page, 0, 2 * sbi->s_dirsize);
	if (err) {
		unlock_page(page);
		goto fail;
	}

	kaddr = kmap_local_page(page);
	memset(kaddr, 0, PAGE_SIZE);

	if (sbi->s_version == MINIX_V3) {
		minix3_dirent *de3 = (minix3_dirent *)kaddr;

		de3->inode = inode->i_ino;
		strcpy(de3->name, ".");
		de3 = minix_next_entry(de3, sbi);
		de3->inode = dir->i_ino;
		strcpy(de3->name, "..");
	} else {
		minix_dirent *de = (minix_dirent *)kaddr;

		de->inode = inode->i_ino;
		strcpy(de->name, ".");
		de = minix_next_entry(de, sbi);
		de->inode = dir->i_ino;
		strcpy(de->name, "..");
	}
	kunmap_local(kaddr);

	dir_commit_chunk(page, 0, 2 * sbi->s_dirsize);
	err = minix_handle_dirsync(inode);
fail:
	put_page(page);
	return err;
}

/*
 * routine to check that the specified directory is empty (for rmdir)
 */
int minix_empty_dir(struct inode * inode)
{
	struct page *page = NULL;
	unsigned long i, npages = dir_pages(inode);
	struct minix_sb_info *sbi = minix_sb(inode->i_sb);
	char *name, *kaddr;
	__u32 inumber;

	for (i = 0; i < npages; i++) {
		char *p, *limit;

		kaddr = dir_get_page(inode, i, &page);
		if (IS_ERR(kaddr))
			continue;

		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;
			}
		}
		unmap_and_put_page(page, kaddr);
	}
	return 1;

not_empty:
	unmap_and_put_page(page, kaddr);
	return 0;
}

/* Releases the page */
int minix_set_link(struct minix_dir_entry *de, struct page *page,
		struct inode *inode)
{
	struct inode *dir = page->mapping->host;
	struct minix_sb_info *sbi = minix_sb(dir->i_sb);
	loff_t pos = page_offset(page) + offset_in_page(de);
	int err;

	lock_page(page);
	err = minix_prepare_chunk(page, pos, sbi->s_dirsize);
	if (err) {
		unlock_page(page);
		return err;
	}
	if (sbi->s_version == MINIX_V3)
		((minix3_dirent *)de)->inode = inode->i_ino;
	else
		de->inode = inode->i_ino;
	dir_commit_chunk(page, pos, sbi->s_dirsize);
	inode_set_mtime_to_ts(dir, inode_set_ctime_current(dir));
	mark_inode_dirty(dir);
	return minix_handle_dirsync(dir);
}

struct minix_dir_entry * minix_dotdot (struct inode *dir, struct page **p)
{
	struct minix_sb_info *sbi = minix_sb(dir->i_sb);
	struct minix_dir_entry *de = dir_get_page(dir, 0, p);

	if (!IS_ERR(de))
		return minix_next_entry(de, sbi);
	return NULL;
}

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;
		unmap_and_put_page(page, de);
	}
	return res;
}
Commit	Line	Data
b2441318	1	// SPDX-License-Identifier: GPL-2.0
1da177e4 LT	2	/*
	3	* linux/fs/minix/dir.c
	4	*
	5	* Copyright (C) 1991, 1992 Linus Torvalds
	6	*
	7	* minix directory handling functions
939b00df AB	8	*
939b00df AB	9	* Updated to filesystem version 3 by Daniel Aragones
1da177e4 LT	10	*/
	11
	12	#include "minix.h"
4a66af9e	13	#include <linux/buffer_head.h>
1da177e4	14	#include <linux/highmem.h>
4a66af9e	15	#include <linux/swap.h>
1da177e4 LT	16
1da177e4 LT	17	typedef struct minix_dir_entry minix_dirent;
939b00df	18	typedef struct minix3_dir_entry minix3_dirent;
1da177e4	19
80886298	20	static int minix_readdir(struct file , struct dir_context );
1da177e4	21
4b6f5d20	22	const struct file_operations minix_dir_operations = {
cc46759a	23	.llseek = generic_file_llseek,
1da177e4	24	.read = generic_read_dir,
3b0a3c1a	25	.iterate_shared = minix_readdir,
1b061d92	26	.fsync = generic_file_fsync,
1da177e4 LT	27	};
1da177e4 LT	28
1da177e4 LT	29	/*
	30	* Return the offset into page `page_nr' of the last valid
	31	* byte in that page, plus one.
	32	*/
	33	static unsigned
	34	minix_last_byte(struct inode *inode, unsigned long page_nr)
	35	{
09cbfeaf	36	unsigned last_byte = PAGE_SIZE;
1da177e4	37
09cbfeaf KS	38	if (page_nr == (inode->i_size >> PAGE_SHIFT))
09cbfeaf KS	39	last_byte = inode->i_size & (PAGE_SIZE - 1);
1da177e4 LT	40	return last_byte;
	41	}
	42
f556e776	43	static void dir_commit_chunk(struct page *page, loff_t pos, unsigned len)
1da177e4	44	{
4a66af9e NP	45	struct address_space *mapping = page->mapping;
4a66af9e NP	46	struct inode *dir = mapping->host;
f556e776	47
4a66af9e NP	48	block_write_end(NULL, mapping, pos, len, len, page, NULL);
	49
	50	if (pos+len > dir->i_size) {
	51	i_size_write(dir, pos+len);
	52	mark_inode_dirty(dir);
	53	}
f556e776 CH	54	unlock_page(page);
	55	}
	56
	57	static int minix_handle_dirsync(struct inode *dir)
	58	{
	59	int err;
	60
	61	err = filemap_write_and_wait(dir->i_mapping);
	62	if (!err)
	63	err = sync_inode_metadata(dir, 1);
1da177e4 LT	64	return err;
	65	}
	66
ee0d27c9	67	static void dir_get_page(struct inode dir, unsigned long n, struct page **p)
1da177e4 LT	68	{
1da177e4 LT	69	struct address_space *mapping = dir->i_mapping;
090d2b18	70	struct page *page = read_mapping_page(mapping, n, NULL);
ee0d27c9 AV	71	if (IS_ERR(page))
ee0d27c9 AV	72	return ERR_CAST(page);
ee0d27c9	73	*p = page;
41e9a7fa	74	return kmap_local_page(page);
1da177e4 LT	75	}
	76
	77	static inline void minix_next_entry(void de, struct minix_sb_info *sbi)
	78	{
	79	return (void)((char)de + sbi->s_dirsize);
	80	}
	81
80886298	82	static int minix_readdir(struct file file, struct dir_context ctx)
1da177e4	83	{
80886298	84	struct inode *inode = file_inode(file);
1da177e4	85	struct super_block *sb = inode->i_sb;
1da177e4 LT	86	struct minix_sb_info *sbi = minix_sb(sb);
1da177e4 LT	87	unsigned chunk_size = sbi->s_dirsize;
80886298 AV	88	unsigned long npages = dir_pages(inode);
	89	unsigned long pos = ctx->pos;
	90	unsigned offset;
	91	unsigned long n;
1da177e4	92
642b704c	93	ctx->pos = pos = ALIGN(pos, chunk_size);
1da177e4	94	if (pos >= inode->i_size)
80886298 AV	95	return 0;
80886298 AV	96
09cbfeaf KS	97	offset = pos & ~PAGE_MASK;
09cbfeaf KS	98	n = pos >> PAGE_SHIFT;
1da177e4 LT	99
	100	for ( ; n < npages; n++, offset = 0) {
	101	char p, kaddr, *limit;
ee0d27c9	102	struct page *page;
1da177e4	103
ee0d27c9 AV	104	kaddr = dir_get_page(inode, n, &page);
ee0d27c9 AV	105	if (IS_ERR(kaddr))
1da177e4	106	continue;
1da177e4 LT	107	p = kaddr+offset;
1da177e4 LT	108	limit = kaddr + minix_last_byte(inode, n) - chunk_size;
939b00df	109	for ( ; p <= limit; p = minix_next_entry(p, sbi)) {
80886298 AV	110	const char *name;
80886298 AV	111	__u32 inumber;
939b00df AB	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) {
939b00df	122	unsigned l = strnlen(name, sbi->s_namelen);
80886298 AV	123	if (!dir_emit(ctx, name, l,
80886298 AV	124	inumber, DT_UNKNOWN)) {
41e9a7fa	125	unmap_and_put_page(page, p);
80886298	126	return 0;
1da177e4 LT	127	}
1da177e4 LT	128	}
80886298	129	ctx->pos += chunk_size;
1da177e4	130	}
41e9a7fa	131	unmap_and_put_page(page, kaddr);
1da177e4	132	}
1da177e4 LT	133	return 0;
	134	}
	135
	136	static inline int namecompare(int len, int maxlen,
	137	const char * name, const char * buffer)
	138	{
	139	if (len < maxlen && buffer[len])
	140	return 0;
	141	return !memcmp(name, buffer, len);
	142	}
	143
	144	/*
	145	* minix_find_entry()
	146	*
	147	* finds an entry in the specified directory with the wanted name. It
	148	* returns the cache buffer in which the entry was found, and the entry
	149	* itself (as a parameter - res_dir). It does NOT read the inode of the
	150	* entry - you'll have to do that yourself if you want to.
	151	*/
	152	minix_dirent minix_find_entry(struct dentry dentry, struct page **res_page)
	153	{
	154	const char * name = dentry->d_name.name;
	155	int namelen = dentry->d_name.len;
2b0143b5	156	struct inode * dir = d_inode(dentry->d_parent);
1da177e4 LT	157	struct super_block * sb = dir->i_sb;
	158	struct minix_sb_info * sbi = minix_sb(sb);
	159	unsigned long n;
	160	unsigned long npages = dir_pages(dir);
	161	struct page *page = NULL;
939b00df	162	char *p;
1da177e4	163
939b00df AB	164	char *namx;
939b00df AB	165	__u32 inumber;
1da177e4 LT	166	*res_page = NULL;
	167
	168	for (n = 0; n < npages; n++) {
939b00df AB	169	char kaddr, limit;
939b00df AB	170
ee0d27c9 AV	171	kaddr = dir_get_page(dir, n, &page);
ee0d27c9 AV	172	if (IS_ERR(kaddr))
1da177e4 LT	173	continue;
1da177e4 LT	174
939b00df AB	175	limit = kaddr + minix_last_byte(dir, n) - sbi->s_dirsize;
	176	for (p = kaddr; p <= limit; p = minix_next_entry(p, sbi)) {
	177	if (sbi->s_version == MINIX_V3) {
	178	minix3_dirent de3 = (minix3_dirent )p;
	179	namx = de3->name;
	180	inumber = de3->inode;
	181	} else {
	182	minix_dirent de = (minix_dirent )p;
	183	namx = de->name;
	184	inumber = de->inode;
	185	}
	186	if (!inumber)
1da177e4	187	continue;
939b00df	188	if (namecompare(namelen, sbi->s_namelen, name, namx))
1da177e4 LT	189	goto found;
1da177e4 LT	190	}
41e9a7fa	191	unmap_and_put_page(page, kaddr);
1da177e4 LT	192	}
	193	return NULL;
	194
	195	found:
	196	*res_page = page;
939b00df	197	return (minix_dirent *)p;
1da177e4 LT	198	}
	199
	200	int minix_add_link(struct dentry dentry, struct inode inode)
	201	{
2b0143b5	202	struct inode *dir = d_inode(dentry->d_parent);
1da177e4 LT	203	const char * name = dentry->d_name.name;
	204	int namelen = dentry->d_name.len;
	205	struct super_block * sb = dir->i_sb;
	206	struct minix_sb_info * sbi = minix_sb(sb);
	207	struct page *page = NULL;
1da177e4 LT	208	unsigned long npages = dir_pages(dir);
1da177e4 LT	209	unsigned long n;
939b00df AB	210	char kaddr, p;
	211	minix_dirent *de;
	212	minix3_dirent *de3;
4a66af9e	213	loff_t pos;
1da177e4	214	int err;
939b00df AB	215	char *namx = NULL;
939b00df AB	216	__u32 inumber;
1da177e4 LT	217
	218	/*
	219	* We take care of directory expansion in the same loop
	220	* This code plays outside i_size, so it locks the page
	221	* to protect that region.
	222	*/
	223	for (n = 0; n <= npages; n++) {
939b00df	224	char limit, dir_end;
1da177e4	225
ee0d27c9 AV	226	kaddr = dir_get_page(dir, n, &page);
	227	if (IS_ERR(kaddr))
	228	return PTR_ERR(kaddr);
1da177e4	229	lock_page(page);
1da177e4	230	dir_end = kaddr + minix_last_byte(dir, n);
09cbfeaf	231	limit = kaddr + PAGE_SIZE - sbi->s_dirsize;
939b00df AB	232	for (p = kaddr; p <= limit; p = minix_next_entry(p, sbi)) {
	233	de = (minix_dirent *)p;
	234	de3 = (minix3_dirent *)p;
	235	if (sbi->s_version == MINIX_V3) {
	236	namx = de3->name;
	237	inumber = de3->inode;
	238	} else {
	239	namx = de->name;
	240	inumber = de->inode;
	241	}
	242	if (p == dir_end) {
1da177e4	243	/* We hit i_size */
939b00df AB	244	if (sbi->s_version == MINIX_V3)
	245	de3->inode = 0;
	246	else
	247	de->inode = 0;
1da177e4 LT	248	goto got_it;
1da177e4 LT	249	}
939b00df	250	if (!inumber)
1da177e4 LT	251	goto got_it;
1da177e4 LT	252	err = -EEXIST;
939b00df	253	if (namecompare(namelen, sbi->s_namelen, name, namx))
1da177e4	254	goto out_unlock;
1da177e4 LT	255	}
1da177e4 LT	256	unlock_page(page);
41e9a7fa	257	unmap_and_put_page(page, kaddr);
1da177e4 LT	258	}
	259	BUG();
	260	return -EINVAL;
	261
	262	got_it:
4812509e	263	pos = page_offset(page) + offset_in_page(p);
f4e420dc	264	err = minix_prepare_chunk(page, pos, sbi->s_dirsize);
1da177e4 LT	265	if (err)
1da177e4 LT	266	goto out_unlock;
939b00df AB	267	memcpy (namx, name, namelen);
	268	if (sbi->s_version == MINIX_V3) {
	269	memset (namx + namelen, 0, sbi->s_dirsize - namelen - 4);
	270	de3->inode = inode->i_ino;
	271	} else {
	272	memset (namx + namelen, 0, sbi->s_dirsize - namelen - 2);
	273	de->inode = inode->i_ino;
	274	}
f556e776	275	dir_commit_chunk(page, pos, sbi->s_dirsize);
06475f4b	276	inode_set_mtime_to_ts(dir, inode_set_ctime_current(dir));
1da177e4	277	mark_inode_dirty(dir);
f556e776	278	err = minix_handle_dirsync(dir);
1da177e4	279	out_put:
41e9a7fa	280	unmap_and_put_page(page, kaddr);
1da177e4 LT	281	return err;
	282	out_unlock:
	283	unlock_page(page);
	284	goto out_put;
	285	}
	286
	287	int minix_delete_entry(struct minix_dir_entry de, struct page page)
	288	{
f4e420dc	289	struct inode *inode = page->mapping->host;
4812509e	290	loff_t pos = page_offset(page) + offset_in_page(de);
9f6c1333 DG	291	struct minix_sb_info *sbi = minix_sb(inode->i_sb);
9f6c1333 DG	292	unsigned len = sbi->s_dirsize;
1da177e4 LT	293	int err;
	294
	295	lock_page(page);
f4e420dc	296	err = minix_prepare_chunk(page, pos, len);
b61d15d5	297	if (err) {
1da177e4	298	unlock_page(page);
b61d15d5	299	return err;
1da177e4	300	}
b61d15d5 CH	301	if (sbi->s_version == MINIX_V3)
	302	((minix3_dirent *)de)->inode = 0;
	303	else
	304	de->inode = 0;
f556e776	305	dir_commit_chunk(page, pos, len);
06475f4b	306	inode_set_mtime_to_ts(inode, inode_set_ctime_current(inode));
1da177e4	307	mark_inode_dirty(inode);
f556e776	308	return minix_handle_dirsync(inode);
1da177e4 LT	309	}
	310
	311	int minix_make_empty(struct inode inode, struct inode dir)
	312	{
f4e420dc	313	struct page *page = grab_cache_page(inode->i_mapping, 0);
939b00df	314	struct minix_sb_info *sbi = minix_sb(inode->i_sb);
1da177e4 LT	315	char *kaddr;
	316	int err;
	317
	318	if (!page)
	319	return -ENOMEM;
f4e420dc	320	err = minix_prepare_chunk(page, 0, 2 * sbi->s_dirsize);
1da177e4 LT	321	if (err) {
	322	unlock_page(page);
	323	goto fail;
	324	}
	325
41e9a7fa	326	kaddr = kmap_local_page(page);
09cbfeaf	327	memset(kaddr, 0, PAGE_SIZE);
1da177e4	328
939b00df AB	329	if (sbi->s_version == MINIX_V3) {
	330	minix3_dirent de3 = (minix3_dirent )kaddr;
	331
	332	de3->inode = inode->i_ino;
	333	strcpy(de3->name, ".");
	334	de3 = minix_next_entry(de3, sbi);
	335	de3->inode = dir->i_ino;
	336	strcpy(de3->name, "..");
	337	} else {
	338	minix_dirent de = (minix_dirent )kaddr;
	339
	340	de->inode = inode->i_ino;
	341	strcpy(de->name, ".");
	342	de = minix_next_entry(de, sbi);
	343	de->inode = dir->i_ino;
	344	strcpy(de->name, "..");
	345	}
41e9a7fa	346	kunmap_local(kaddr);
1da177e4	347
f556e776 CH	348	dir_commit_chunk(page, 0, 2 * sbi->s_dirsize);
f556e776 CH	349	err = minix_handle_dirsync(inode);
1da177e4	350	fail:
09cbfeaf	351	put_page(page);
1da177e4 LT	352	return err;
	353	}
	354
	355	/*
	356	* routine to check that the specified directory is empty (for rmdir)
	357	*/
	358	int minix_empty_dir(struct inode * inode)
	359	{
	360	struct page *page = NULL;
	361	unsigned long i, npages = dir_pages(inode);
	362	struct minix_sb_info *sbi = minix_sb(inode->i_sb);
41e9a7fa	363	char name, kaddr;
939b00df	364	__u32 inumber;
1da177e4 LT	365
1da177e4 LT	366	for (i = 0; i < npages; i++) {
41e9a7fa	367	char p, limit;
1da177e4	368
ee0d27c9 AV	369	kaddr = dir_get_page(inode, i, &page);
ee0d27c9 AV	370	if (IS_ERR(kaddr))
1da177e4 LT	371	continue;
1da177e4 LT	372
939b00df AB	373	limit = kaddr + minix_last_byte(inode, i) - sbi->s_dirsize;
	374	for (p = kaddr; p <= limit; p = minix_next_entry(p, sbi)) {
	375	if (sbi->s_version == MINIX_V3) {
	376	minix3_dirent de3 = (minix3_dirent )p;
	377	name = de3->name;
	378	inumber = de3->inode;
	379	} else {
	380	minix_dirent de = (minix_dirent )p;
	381	name = de->name;
	382	inumber = de->inode;
	383	}
1da177e4	384
939b00df	385	if (inumber != 0) {
1da177e4	386	/* check for . and .. */
939b00df	387	if (name[0] != '.')
1da177e4	388	goto not_empty;
939b00df AB	389	if (!name[1]) {
939b00df AB	390	if (inumber != inode->i_ino)
1da177e4	391	goto not_empty;
939b00df	392	} else if (name[1] != '.')
1da177e4	393	goto not_empty;
939b00df	394	else if (name[2])
1da177e4 LT	395	goto not_empty;
1da177e4 LT	396	}
1da177e4	397	}
41e9a7fa	398	unmap_and_put_page(page, kaddr);
1da177e4 LT	399	}
	400	return 1;
	401
	402	not_empty:
41e9a7fa	403	unmap_and_put_page(page, kaddr);
1da177e4 LT	404	return 0;
	405	}
	406
	407	/* Releases the page */
2d1a9d59 CH	408	int minix_set_link(struct minix_dir_entry de, struct page page,
2d1a9d59 CH	409	struct inode *inode)
1da177e4	410	{
f4e420dc	411	struct inode *dir = page->mapping->host;
1da177e4	412	struct minix_sb_info *sbi = minix_sb(dir->i_sb);
4812509e	413	loff_t pos = page_offset(page) + offset_in_page(de);
1da177e4 LT	414	int err;
	415
	416	lock_page(page);
f4e420dc	417	err = minix_prepare_chunk(page, pos, sbi->s_dirsize);
2d1a9d59	418	if (err) {
1da177e4	419	unlock_page(page);
2d1a9d59	420	return err;
1da177e4	421	}
2d1a9d59 CH	422	if (sbi->s_version == MINIX_V3)
	423	((minix3_dirent *)de)->inode = inode->i_ino;
	424	else
	425	de->inode = inode->i_ino;
f556e776	426	dir_commit_chunk(page, pos, sbi->s_dirsize);
06475f4b	427	inode_set_mtime_to_ts(dir, inode_set_ctime_current(dir));
1da177e4	428	mark_inode_dirty(dir);
f556e776	429	return minix_handle_dirsync(dir);
1da177e4 LT	430	}
	431
	432	struct minix_dir_entry * minix_dotdot (struct inode dir, struct page *p)
	433	{
1da177e4	434	struct minix_sb_info *sbi = minix_sb(dir->i_sb);
ee0d27c9	435	struct minix_dir_entry *de = dir_get_page(dir, 0, p);
1da177e4	436
ee0d27c9 AV	437	if (!IS_ERR(de))
	438	return minix_next_entry(de, sbi);
	439	return NULL;
1da177e4 LT	440	}
	441
	442	ino_t minix_inode_by_name(struct dentry *dentry)
	443	{
	444	struct page *page;
	445	struct minix_dir_entry *de = minix_find_entry(dentry, &page);
	446	ino_t res = 0;
	447
	448	if (de) {
9f6c1333 DG	449	struct address_space *mapping = page->mapping;
	450	struct inode *inode = mapping->host;
	451	struct minix_sb_info *sbi = minix_sb(inode->i_sb);
	452
	453	if (sbi->s_version == MINIX_V3)
	454	res = ((minix3_dirent *) de)->inode;
	455	else
	456	res = de->inode;
41e9a7fa	457	unmap_and_put_page(page, de);
1da177e4 LT	458	}
	459	return res;
	460	}