[net-next-2.6.git] / fs / minix / dir.c

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

#include "minix.h"
#include <linux/buffer_head.h>
#include <linux/highmem.h>
#include <linux/smp_lock.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 = {
	.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;

	lock_kernel();

	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;
	unlock_kernel();
	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;
	unsigned len = minix_sb(inode->i_sb)->s_dirsize;
	int err;

	lock_page(page);
	err = __minix_write_begin(NULL, mapping, pos, len,
					AOP_FLAG_UNINTERRUPTIBLE, &page, NULL);
	if (err == 0) {
		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) {
		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) {
		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 LT	13	#include <linux/highmem.h>
1da177e4 LT	14	#include <linux/smp_lock.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 LT	19
	20	static int minix_readdir(struct file , void , filldir_t);
	21
4b6f5d20	22	const struct file_operations minix_dir_operations = {
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 LT	104
	105	lock_kernel();
	106
	107	pos = (pos + chunk_size-1) & ~(chunk_size-1);
	108	if (pos >= inode->i_size)
	109	goto done;
	110
	111	for ( ; n < npages; n++, offset = 0) {
	112	char p, kaddr, *limit;
	113	struct page *page = dir_get_page(inode, n);
	114
	115	if (IS_ERR(page))
	116	continue;
	117	kaddr = (char *)page_address(page);
	118	p = kaddr+offset;
	119	limit = kaddr + minix_last_byte(inode, n) - chunk_size;
939b00df AB	120	for ( ; p <= limit; p = minix_next_entry(p, sbi)) {
	121	if (sbi->s_version == MINIX_V3) {
	122	minix3_dirent de3 = (minix3_dirent )p;
	123	name = de3->name;
	124	inumber = de3->inode;
	125	} else {
	126	minix_dirent de = (minix_dirent )p;
	127	name = de->name;
	128	inumber = de->inode;
	129	}
	130	if (inumber) {
1da177e4	131	int over;
1da177e4	132
939b00df	133	unsigned l = strnlen(name, sbi->s_namelen);
1da177e4	134	offset = p - kaddr;
939b00df AB	135	over = filldir(dirent, name, l,
	136	(n << PAGE_CACHE_SHIFT) \| offset,
	137	inumber, DT_UNKNOWN);
1da177e4 LT	138	if (over) {
	139	dir_put_page(page);
	140	goto done;
	141	}
	142	}
	143	}
	144	dir_put_page(page);
	145	}
	146
	147	done:
	148	filp->f_pos = (n << PAGE_CACHE_SHIFT) \| offset;
	149	unlock_kernel();
	150	return 0;
	151	}
	152
	153	static inline int namecompare(int len, int maxlen,
	154	const char * name, const char * buffer)
	155	{
	156	if (len < maxlen && buffer[len])
	157	return 0;
	158	return !memcmp(name, buffer, len);
	159	}
	160
	161	/*
	162	* minix_find_entry()
	163	*
	164	* finds an entry in the specified directory with the wanted name. It
	165	* returns the cache buffer in which the entry was found, and the entry
	166	* itself (as a parameter - res_dir). It does NOT read the inode of the
	167	* entry - you'll have to do that yourself if you want to.
	168	*/
	169	minix_dirent minix_find_entry(struct dentry dentry, struct page **res_page)
	170	{
	171	const char * name = dentry->d_name.name;
	172	int namelen = dentry->d_name.len;
	173	struct inode * dir = dentry->d_parent->d_inode;
	174	struct super_block * sb = dir->i_sb;
	175	struct minix_sb_info * sbi = minix_sb(sb);
	176	unsigned long n;
	177	unsigned long npages = dir_pages(dir);
	178	struct page *page = NULL;
939b00df	179	char *p;
1da177e4	180
939b00df AB	181	char *namx;
939b00df AB	182	__u32 inumber;
1da177e4 LT	183	*res_page = NULL;
	184
	185	for (n = 0; n < npages; n++) {
939b00df AB	186	char kaddr, limit;
939b00df AB	187
1da177e4 LT	188	page = dir_get_page(dir, n);
	189	if (IS_ERR(page))
	190	continue;
	191
	192	kaddr = (char*)page_address(page);
939b00df AB	193	limit = kaddr + minix_last_byte(dir, n) - sbi->s_dirsize;
	194	for (p = kaddr; p <= limit; p = minix_next_entry(p, sbi)) {
	195	if (sbi->s_version == MINIX_V3) {
	196	minix3_dirent de3 = (minix3_dirent )p;
	197	namx = de3->name;
	198	inumber = de3->inode;
	199	} else {
	200	minix_dirent de = (minix_dirent )p;
	201	namx = de->name;
	202	inumber = de->inode;
	203	}
	204	if (!inumber)
1da177e4	205	continue;
939b00df	206	if (namecompare(namelen, sbi->s_namelen, name, namx))
1da177e4 LT	207	goto found;
	208	}
	209	dir_put_page(page);
	210	}
	211	return NULL;
	212
	213	found:
	214	*res_page = page;
939b00df	215	return (minix_dirent *)p;
1da177e4 LT	216	}
	217
	218	int minix_add_link(struct dentry dentry, struct inode inode)
	219	{
	220	struct inode *dir = dentry->d_parent->d_inode;
	221	const char * name = dentry->d_name.name;
	222	int namelen = dentry->d_name.len;
	223	struct super_block * sb = dir->i_sb;
	224	struct minix_sb_info * sbi = minix_sb(sb);
	225	struct page *page = NULL;
1da177e4 LT	226	unsigned long npages = dir_pages(dir);
1da177e4 LT	227	unsigned long n;
939b00df AB	228	char kaddr, p;
	229	minix_dirent *de;
	230	minix3_dirent *de3;
4a66af9e	231	loff_t pos;
1da177e4	232	int err;
939b00df AB	233	char *namx = NULL;
939b00df AB	234	__u32 inumber;
1da177e4 LT	235
	236	/*
	237	* We take care of directory expansion in the same loop
	238	* This code plays outside i_size, so it locks the page
	239	* to protect that region.
	240	*/
	241	for (n = 0; n <= npages; n++) {
939b00df	242	char limit, dir_end;
1da177e4 LT	243
	244	page = dir_get_page(dir, n);
	245	err = PTR_ERR(page);
	246	if (IS_ERR(page))
	247	goto out;
	248	lock_page(page);
	249	kaddr = (char*)page_address(page);
	250	dir_end = kaddr + minix_last_byte(dir, n);
939b00df AB	251	limit = kaddr + PAGE_CACHE_SIZE - sbi->s_dirsize;
	252	for (p = kaddr; p <= limit; p = minix_next_entry(p, sbi)) {
	253	de = (minix_dirent *)p;
	254	de3 = (minix3_dirent *)p;
	255	if (sbi->s_version == MINIX_V3) {
	256	namx = de3->name;
	257	inumber = de3->inode;
	258	} else {
	259	namx = de->name;
	260	inumber = de->inode;
	261	}
	262	if (p == dir_end) {
1da177e4	263	/* We hit i_size */
939b00df AB	264	if (sbi->s_version == MINIX_V3)
	265	de3->inode = 0;
	266	else
	267	de->inode = 0;
1da177e4 LT	268	goto got_it;
1da177e4 LT	269	}
939b00df	270	if (!inumber)
1da177e4 LT	271	goto got_it;
1da177e4 LT	272	err = -EEXIST;
939b00df	273	if (namecompare(namelen, sbi->s_namelen, name, namx))
1da177e4	274	goto out_unlock;
1da177e4 LT	275	}
	276	unlock_page(page);
	277	dir_put_page(page);
	278	}
	279	BUG();
	280	return -EINVAL;
	281
	282	got_it:
d6b54841	283	pos = page_offset(page) + p - (char *)page_address(page);
4a66af9e NP	284	err = __minix_write_begin(NULL, page->mapping, pos, sbi->s_dirsize,
4a66af9e NP	285	AOP_FLAG_UNINTERRUPTIBLE, &page, NULL);
1da177e4 LT	286	if (err)
1da177e4 LT	287	goto out_unlock;
939b00df AB	288	memcpy (namx, name, namelen);
	289	if (sbi->s_version == MINIX_V3) {
	290	memset (namx + namelen, 0, sbi->s_dirsize - namelen - 4);
	291	de3->inode = inode->i_ino;
	292	} else {
	293	memset (namx + namelen, 0, sbi->s_dirsize - namelen - 2);
	294	de->inode = inode->i_ino;
	295	}
4a66af9e	296	err = dir_commit_chunk(page, pos, sbi->s_dirsize);
1da177e4 LT	297	dir->i_mtime = dir->i_ctime = CURRENT_TIME_SEC;
	298	mark_inode_dirty(dir);
	299	out_put:
	300	dir_put_page(page);
	301	out:
	302	return err;
	303	out_unlock:
	304	unlock_page(page);
	305	goto out_put;
	306	}
	307
	308	int minix_delete_entry(struct minix_dir_entry de, struct page page)
	309	{
	310	struct address_space *mapping = page->mapping;
	311	struct inode inode = (struct inode)mapping->host;
	312	char *kaddr = page_address(page);
4a66af9e NP	313	loff_t pos = page_offset(page) + (char*)de - kaddr;
4a66af9e NP	314	unsigned len = minix_sb(inode->i_sb)->s_dirsize;
1da177e4 LT	315	int err;
	316
	317	lock_page(page);
4a66af9e NP	318	err = __minix_write_begin(NULL, mapping, pos, len,
4a66af9e NP	319	AOP_FLAG_UNINTERRUPTIBLE, &page, NULL);
1da177e4 LT	320	if (err == 0) {
1da177e4 LT	321	de->inode = 0;
4a66af9e	322	err = dir_commit_chunk(page, pos, len);
1da177e4 LT	323	} else {
	324	unlock_page(page);
	325	}
	326	dir_put_page(page);
	327	inode->i_ctime = inode->i_mtime = CURRENT_TIME_SEC;
	328	mark_inode_dirty(inode);
	329	return err;
	330	}
	331
	332	int minix_make_empty(struct inode inode, struct inode dir)
	333	{
	334	struct address_space *mapping = inode->i_mapping;
	335	struct page *page = grab_cache_page(mapping, 0);
939b00df	336	struct minix_sb_info *sbi = minix_sb(inode->i_sb);
1da177e4 LT	337	char *kaddr;
	338	int err;
	339
	340	if (!page)
	341	return -ENOMEM;
4a66af9e NP	342	err = __minix_write_begin(NULL, mapping, 0, 2 * sbi->s_dirsize,
4a66af9e NP	343	AOP_FLAG_UNINTERRUPTIBLE, &page, NULL);
1da177e4 LT	344	if (err) {
	345	unlock_page(page);
	346	goto fail;
	347	}
	348
	349	kaddr = kmap_atomic(page, KM_USER0);
	350	memset(kaddr, 0, PAGE_CACHE_SIZE);
	351
939b00df AB	352	if (sbi->s_version == MINIX_V3) {
	353	minix3_dirent de3 = (minix3_dirent )kaddr;
	354
	355	de3->inode = inode->i_ino;
	356	strcpy(de3->name, ".");
	357	de3 = minix_next_entry(de3, sbi);
	358	de3->inode = dir->i_ino;
	359	strcpy(de3->name, "..");
	360	} else {
	361	minix_dirent de = (minix_dirent )kaddr;
	362
	363	de->inode = inode->i_ino;
	364	strcpy(de->name, ".");
	365	de = minix_next_entry(de, sbi);
	366	de->inode = dir->i_ino;
	367	strcpy(de->name, "..");
	368	}
1da177e4 LT	369	kunmap_atomic(kaddr, KM_USER0);
	370
	371	err = dir_commit_chunk(page, 0, 2 * sbi->s_dirsize);
	372	fail:
	373	page_cache_release(page);
	374	return err;
	375	}
	376
	377	/*
	378	* routine to check that the specified directory is empty (for rmdir)
	379	*/
	380	int minix_empty_dir(struct inode * inode)
	381	{
	382	struct page *page = NULL;
	383	unsigned long i, npages = dir_pages(inode);
	384	struct minix_sb_info *sbi = minix_sb(inode->i_sb);
939b00df AB	385	char *name;
939b00df AB	386	__u32 inumber;
1da177e4 LT	387
1da177e4 LT	388	for (i = 0; i < npages; i++) {
939b00df	389	char p, kaddr, *limit;
1da177e4	390
939b00df	391	page = dir_get_page(inode, i);
1da177e4 LT	392	if (IS_ERR(page))
	393	continue;
	394
	395	kaddr = (char *)page_address(page);
939b00df AB	396	limit = kaddr + minix_last_byte(inode, i) - sbi->s_dirsize;
	397	for (p = kaddr; p <= limit; p = minix_next_entry(p, sbi)) {
	398	if (sbi->s_version == MINIX_V3) {
	399	minix3_dirent de3 = (minix3_dirent )p;
	400	name = de3->name;
	401	inumber = de3->inode;
	402	} else {
	403	minix_dirent de = (minix_dirent )p;
	404	name = de->name;
	405	inumber = de->inode;
	406	}
1da177e4	407
939b00df	408	if (inumber != 0) {
1da177e4	409	/* check for . and .. */
939b00df	410	if (name[0] != '.')
1da177e4	411	goto not_empty;
939b00df AB	412	if (!name[1]) {
939b00df AB	413	if (inumber != inode->i_ino)
1da177e4	414	goto not_empty;
939b00df	415	} else if (name[1] != '.')
1da177e4	416	goto not_empty;
939b00df	417	else if (name[2])
1da177e4 LT	418	goto not_empty;
1da177e4 LT	419	}
1da177e4 LT	420	}
	421	dir_put_page(page);
	422	}
	423	return 1;
	424
	425	not_empty:
	426	dir_put_page(page);
	427	return 0;
	428	}
	429
	430	/* Releases the page */
	431	void minix_set_link(struct minix_dir_entry de, struct page page,
	432	struct inode *inode)
	433	{
4a66af9e NP	434	struct address_space *mapping = page->mapping;
4a66af9e NP	435	struct inode *dir = mapping->host;
1da177e4	436	struct minix_sb_info *sbi = minix_sb(dir->i_sb);
4a66af9e NP	437	loff_t pos = page_offset(page) +
4a66af9e NP	438	(char )de-(char)page_address(page);
1da177e4 LT	439	int err;
	440
	441	lock_page(page);
4a66af9e NP	442
	443	err = __minix_write_begin(NULL, mapping, pos, sbi->s_dirsize,
	444	AOP_FLAG_UNINTERRUPTIBLE, &page, NULL);
1da177e4 LT	445	if (err == 0) {
1da177e4 LT	446	de->inode = inode->i_ino;
4a66af9e	447	err = dir_commit_chunk(page, pos, sbi->s_dirsize);
1da177e4 LT	448	} else {
	449	unlock_page(page);
	450	}
	451	dir_put_page(page);
	452	dir->i_mtime = dir->i_ctime = CURRENT_TIME_SEC;
	453	mark_inode_dirty(dir);
	454	}
	455
	456	struct minix_dir_entry * minix_dotdot (struct inode dir, struct page *p)
	457	{
	458	struct page *page = dir_get_page(dir, 0);
	459	struct minix_sb_info *sbi = minix_sb(dir->i_sb);
	460	struct minix_dir_entry *de = NULL;
	461
	462	if (!IS_ERR(page)) {
	463	de = minix_next_entry(page_address(page), sbi);
	464	*p = page;
	465	}
	466	return de;
	467	}
	468
	469	ino_t minix_inode_by_name(struct dentry *dentry)
	470	{
	471	struct page *page;
	472	struct minix_dir_entry *de = minix_find_entry(dentry, &page);
	473	ino_t res = 0;
	474
	475	if (de) {
	476	res = de->inode;
	477	dir_put_page(page);
	478	}
	479	return res;
	480	}