[linux.git] / fs / sysv / namei.c

/*
 *  linux/fs/sysv/namei.c
 *
 *  minix/namei.c
 *  Copyright (C) 1991, 1992  Linus Torvalds
 *
 *  coh/namei.c
 *  Copyright (C) 1993  Pascal Haible, Bruno Haible
 *
 *  sysv/namei.c
 *  Copyright (C) 1993  Bruno Haible
 *  Copyright (C) 1997, 1998  Krzysztof G. Baranowski
 */

#include <linux/pagemap.h>
#include <linux/smp_lock.h>
#include "sysv.h"

static int add_nondir(struct dentry *dentry, struct inode *inode)
{
	int err = sysv_add_link(dentry, inode);
	if (!err) {
		d_instantiate(dentry, inode);
		return 0;
	}
	inode_dec_link_count(inode);
	iput(inode);
	return err;
}

static int sysv_hash(struct dentry *dentry, struct qstr *qstr)
{
	/* Truncate the name in place, avoids having to define a compare
	   function. */
	if (qstr->len > SYSV_NAMELEN) {
		qstr->len = SYSV_NAMELEN;
		qstr->hash = full_name_hash(qstr->name, qstr->len);
	}
	return 0;
}

struct dentry_operations sysv_dentry_operations = {
	.d_hash		= sysv_hash,
};

static struct dentry *sysv_lookup(struct inode * dir, struct dentry * dentry, struct nameidata *nd)
{
	struct inode * inode = NULL;
	ino_t ino;

	dentry->d_op = dir->i_sb->s_root->d_op;
	if (dentry->d_name.len > SYSV_NAMELEN)
		return ERR_PTR(-ENAMETOOLONG);
	ino = sysv_inode_by_name(dentry);

	if (ino) {
		inode = iget(dir->i_sb, ino);
		if (!inode)
			return ERR_PTR(-EACCES);
	}
	d_add(dentry, inode);
	return NULL;
}

static int sysv_mknod(struct inode * dir, struct dentry * dentry, int mode, dev_t rdev)
{
	struct inode * inode;
	int err;

	if (!old_valid_dev(rdev))
		return -EINVAL;

	inode = sysv_new_inode(dir, mode);
	err = PTR_ERR(inode);

	if (!IS_ERR(inode)) {
		sysv_set_inode(inode, rdev);
		mark_inode_dirty(inode);
		err = add_nondir(dentry, inode);
	}
	return err;
}

static int sysv_create(struct inode * dir, struct dentry * dentry, int mode, struct nameidata *nd)
{
	return sysv_mknod(dir, dentry, mode, 0);
}

static int sysv_symlink(struct inode * dir, struct dentry * dentry, 
	const char * symname)
{
	int err = -ENAMETOOLONG;
	int l = strlen(symname)+1;
	struct inode * inode;

	if (l > dir->i_sb->s_blocksize)
		goto out;

	inode = sysv_new_inode(dir, S_IFLNK|0777);
	err = PTR_ERR(inode);
	if (IS_ERR(inode))
		goto out;
	
	sysv_set_inode(inode, 0);
	err = page_symlink(inode, symname, l);
	if (err)
		goto out_fail;

	mark_inode_dirty(inode);
	err = add_nondir(dentry, inode);
out:
	return err;

out_fail:
	inode_dec_link_count(inode);
	iput(inode);
	goto out;
}

static int sysv_link(struct dentry * old_dentry, struct inode * dir, 
	struct dentry * dentry)
{
	struct inode *inode = old_dentry->d_inode;

	if (inode->i_nlink >= SYSV_SB(inode->i_sb)->s_link_max)
		return -EMLINK;

	inode->i_ctime = CURRENT_TIME_SEC;
	inode_inc_link_count(inode);
	atomic_inc(&inode->i_count);

	return add_nondir(dentry, inode);
}

static int sysv_mkdir(struct inode * dir, struct dentry *dentry, int mode)
{
	struct inode * inode;
	int err = -EMLINK;

	if (dir->i_nlink >= SYSV_SB(dir->i_sb)->s_link_max) 
		goto out;
	inode_inc_link_count(dir);

	inode = sysv_new_inode(dir, S_IFDIR|mode);
	err = PTR_ERR(inode);
	if (IS_ERR(inode))
		goto out_dir;

	sysv_set_inode(inode, 0);

	inode_inc_link_count(inode);

	err = sysv_make_empty(inode, dir);
	if (err)
		goto out_fail;

	err = sysv_add_link(dentry, inode);
	if (err)
		goto out_fail;

        d_instantiate(dentry, inode);
out:
	return err;

out_fail:
	inode_dec_link_count(inode);
	inode_dec_link_count(inode);
	iput(inode);
out_dir:
	inode_dec_link_count(dir);
	goto out;
}

static int sysv_unlink(struct inode * dir, struct dentry * dentry)
{
	struct inode * inode = dentry->d_inode;
	struct page * page;
	struct sysv_dir_entry * de;
	int err = -ENOENT;

	de = sysv_find_entry(dentry, &page);
	if (!de)
		goto out;

	err = sysv_delete_entry (de, page);
	if (err)
		goto out;

	inode->i_ctime = dir->i_ctime;
	inode_dec_link_count(inode);
out:
	return err;
}

static int sysv_rmdir(struct inode * dir, struct dentry * dentry)
{
	struct inode *inode = dentry->d_inode;
	int err = -ENOTEMPTY;

	if (sysv_empty_dir(inode)) {
		err = sysv_unlink(dir, dentry);
		if (!err) {
			inode->i_size = 0;
			inode_dec_link_count(inode);
			inode_dec_link_count(dir);
		}
	}
	return err;
}

/*
 * Anybody can rename anything with this: the permission checks are left to the
 * higher-level routines.
 */
static int sysv_rename(struct inode * old_dir, struct dentry * old_dentry,
		  struct inode * new_dir, struct dentry * new_dentry)
{
	struct inode * old_inode = old_dentry->d_inode;
	struct inode * new_inode = new_dentry->d_inode;
	struct page * dir_page = NULL;
	struct sysv_dir_entry * dir_de = NULL;
	struct page * old_page;
	struct sysv_dir_entry * old_de;
	int err = -ENOENT;

	old_de = sysv_find_entry(old_dentry, &old_page);
	if (!old_de)
		goto out;

	if (S_ISDIR(old_inode->i_mode)) {
		err = -EIO;
		dir_de = sysv_dotdot(old_inode, &dir_page);
		if (!dir_de)
			goto out_old;
	}

	if (new_inode) {
		struct page * new_page;
		struct sysv_dir_entry * new_de;

		err = -ENOTEMPTY;
		if (dir_de && !sysv_empty_dir(new_inode))
			goto out_dir;

		err = -ENOENT;
		new_de = sysv_find_entry(new_dentry, &new_page);
		if (!new_de)
			goto out_dir;
		inode_inc_link_count(old_inode);
		sysv_set_link(new_de, new_page, old_inode);
		new_inode->i_ctime = CURRENT_TIME_SEC;
		if (dir_de)
			drop_nlink(new_inode);
		inode_dec_link_count(new_inode);
	} else {
		if (dir_de) {
			err = -EMLINK;
			if (new_dir->i_nlink >= SYSV_SB(new_dir->i_sb)->s_link_max)
				goto out_dir;
		}
		inode_inc_link_count(old_inode);
		err = sysv_add_link(new_dentry, old_inode);
		if (err) {
			inode_dec_link_count(old_inode);
			goto out_dir;
		}
		if (dir_de)
			inode_inc_link_count(new_dir);
	}

	sysv_delete_entry(old_de, old_page);
	inode_dec_link_count(old_inode);

	if (dir_de) {
		sysv_set_link(dir_de, dir_page, new_dir);
		inode_dec_link_count(old_dir);
	}
	return 0;

out_dir:
	if (dir_de) {
		kunmap(dir_page);
		page_cache_release(dir_page);
	}
out_old:
	kunmap(old_page);
	page_cache_release(old_page);
out:
	return err;
}

/*
 * directories can handle most operations...
 */
struct inode_operations sysv_dir_inode_operations = {
	.create		= sysv_create,
	.lookup		= sysv_lookup,
	.link		= sysv_link,
	.unlink		= sysv_unlink,
	.symlink	= sysv_symlink,
	.mkdir		= sysv_mkdir,
	.rmdir		= sysv_rmdir,
	.mknod		= sysv_mknod,
	.rename		= sysv_rename,
	.getattr	= sysv_getattr,
};
Commit	Line	Data
1da177e4 LT	1	/*
	2	* linux/fs/sysv/namei.c
	3	*
	4	* minix/namei.c
	5	* Copyright (C) 1991, 1992 Linus Torvalds
	6	*
	7	* coh/namei.c
	8	* Copyright (C) 1993 Pascal Haible, Bruno Haible
	9	*
	10	* sysv/namei.c
	11	* Copyright (C) 1993 Bruno Haible
	12	* Copyright (C) 1997, 1998 Krzysztof G. Baranowski
	13	*/
	14
	15	#include <linux/pagemap.h>
	16	#include <linux/smp_lock.h>
	17	#include "sysv.h"
	18
1da177e4 LT	19	static int add_nondir(struct dentry dentry, struct inode inode)
	20	{
	21	int err = sysv_add_link(dentry, inode);
	22	if (!err) {
	23	d_instantiate(dentry, inode);
	24	return 0;
	25	}
4e907c3d	26	inode_dec_link_count(inode);
1da177e4 LT	27	iput(inode);
	28	return err;
	29	}
	30
	31	static int sysv_hash(struct dentry dentry, struct qstr qstr)
	32	{
	33	/* Truncate the name in place, avoids having to define a compare
	34	function. */
	35	if (qstr->len > SYSV_NAMELEN) {
	36	qstr->len = SYSV_NAMELEN;
	37	qstr->hash = full_name_hash(qstr->name, qstr->len);
	38	}
	39	return 0;
	40	}
	41
	42	struct dentry_operations sysv_dentry_operations = {
	43	.d_hash = sysv_hash,
	44	};
	45
	46	static struct dentry sysv_lookup(struct inode dir, struct dentry * dentry, struct nameidata *nd)
	47	{
	48	struct inode * inode = NULL;
	49	ino_t ino;
	50
	51	dentry->d_op = dir->i_sb->s_root->d_op;
	52	if (dentry->d_name.len > SYSV_NAMELEN)
	53	return ERR_PTR(-ENAMETOOLONG);
	54	ino = sysv_inode_by_name(dentry);
	55
	56	if (ino) {
	57	inode = iget(dir->i_sb, ino);
	58	if (!inode)
	59	return ERR_PTR(-EACCES);
	60	}
	61	d_add(dentry, inode);
	62	return NULL;
	63	}
	64
	65	static int sysv_mknod(struct inode * dir, struct dentry * dentry, int mode, dev_t rdev)
	66	{
	67	struct inode * inode;
	68	int err;
	69
	70	if (!old_valid_dev(rdev))
	71	return -EINVAL;
	72
	73	inode = sysv_new_inode(dir, mode);
	74	err = PTR_ERR(inode);
	75
	76	if (!IS_ERR(inode)) {
	77	sysv_set_inode(inode, rdev);
	78	mark_inode_dirty(inode);
	79	err = add_nondir(dentry, inode);
	80	}
	81	return err;
	82	}
	83
	84	static int sysv_create(struct inode * dir, struct dentry * dentry, int mode, struct nameidata *nd)
	85	{
	86	return sysv_mknod(dir, dentry, mode, 0);
	87	}
	88
	89	static int sysv_symlink(struct inode * dir, struct dentry * dentry,
	90	const char * symname)
91	{
92	int err = -ENAMETOOLONG;
93	int l = strlen(symname)+1;
94	struct inode * inode;
95
96	if (l > dir->i_sb->s_blocksize)
97	goto out;
98
99	inode = sysv_new_inode(dir, S_IFLNK\|0777);
100	err = PTR_ERR(inode);
101	if (IS_ERR(inode))
102	goto out;
103
104	sysv_set_inode(inode, 0);
105	err = page_symlink(inode, symname, l);
106	if (err)
107	goto out_fail;
108
109	mark_inode_dirty(inode);
110	err = add_nondir(dentry, inode);
111	out:
112	return err;
113
114	out_fail:
4e907c3d	115	inode_dec_link_count(inode);
1da177e4 LT	116	iput(inode);
	117	goto out;
	118	}
	119
	120	static int sysv_link(struct dentry * old_dentry, struct inode * dir,
	121	struct dentry * dentry)
	122	{
	123	struct inode *inode = old_dentry->d_inode;
	124
	125	if (inode->i_nlink >= SYSV_SB(inode->i_sb)->s_link_max)
	126	return -EMLINK;
	127
	128	inode->i_ctime = CURRENT_TIME_SEC;
4e907c3d	129	inode_inc_link_count(inode);
1da177e4 LT	130	atomic_inc(&inode->i_count);
	131
	132	return add_nondir(dentry, inode);
	133	}
	134
	135	static int sysv_mkdir(struct inode * dir, struct dentry *dentry, int mode)
	136	{
	137	struct inode * inode;
	138	int err = -EMLINK;
	139
	140	if (dir->i_nlink >= SYSV_SB(dir->i_sb)->s_link_max)
	141	goto out;
4e907c3d	142	inode_inc_link_count(dir);
1da177e4 LT	143
	144	inode = sysv_new_inode(dir, S_IFDIR\|mode);
	145	err = PTR_ERR(inode);
	146	if (IS_ERR(inode))
	147	goto out_dir;
	148
	149	sysv_set_inode(inode, 0);
	150
4e907c3d	151	inode_inc_link_count(inode);
1da177e4 LT	152
	153	err = sysv_make_empty(inode, dir);
	154	if (err)
	155	goto out_fail;
	156
	157	err = sysv_add_link(dentry, inode);
	158	if (err)
	159	goto out_fail;
	160
	161	d_instantiate(dentry, inode);
	162	out:
	163	return err;
	164
	165	out_fail:
4e907c3d AD	166	inode_dec_link_count(inode);
4e907c3d AD	167	inode_dec_link_count(inode);
1da177e4 LT	168	iput(inode);
1da177e4 LT	169	out_dir:
4e907c3d	170	inode_dec_link_count(dir);
1da177e4 LT	171	goto out;
	172	}
	173
	174	static int sysv_unlink(struct inode * dir, struct dentry * dentry)
	175	{
	176	struct inode * inode = dentry->d_inode;
	177	struct page * page;
	178	struct sysv_dir_entry * de;
	179	int err = -ENOENT;
	180
	181	de = sysv_find_entry(dentry, &page);
	182	if (!de)
	183	goto out;
	184
	185	err = sysv_delete_entry (de, page);
	186	if (err)
	187	goto out;
	188
	189	inode->i_ctime = dir->i_ctime;
4e907c3d	190	inode_dec_link_count(inode);
1da177e4 LT	191	out:
	192	return err;
	193	}
	194
	195	static int sysv_rmdir(struct inode * dir, struct dentry * dentry)
	196	{
	197	struct inode *inode = dentry->d_inode;
	198	int err = -ENOTEMPTY;
	199
	200	if (sysv_empty_dir(inode)) {
	201	err = sysv_unlink(dir, dentry);
	202	if (!err) {
	203	inode->i_size = 0;
4e907c3d AD	204	inode_dec_link_count(inode);
4e907c3d AD	205	inode_dec_link_count(dir);
1da177e4 LT	206	}
	207	}
	208	return err;
	209	}
	210
	211	/*
	212	* Anybody can rename anything with this: the permission checks are left to the
	213	* higher-level routines.
	214	*/
	215	static int sysv_rename(struct inode * old_dir, struct dentry * old_dentry,
	216	struct inode * new_dir, struct dentry * new_dentry)
	217	{
	218	struct inode * old_inode = old_dentry->d_inode;
	219	struct inode * new_inode = new_dentry->d_inode;
	220	struct page * dir_page = NULL;
	221	struct sysv_dir_entry * dir_de = NULL;
	222	struct page * old_page;
	223	struct sysv_dir_entry * old_de;
	224	int err = -ENOENT;
	225
	226	old_de = sysv_find_entry(old_dentry, &old_page);
	227	if (!old_de)
	228	goto out;
	229
	230	if (S_ISDIR(old_inode->i_mode)) {
	231	err = -EIO;
	232	dir_de = sysv_dotdot(old_inode, &dir_page);
	233	if (!dir_de)
	234	goto out_old;
	235	}
	236
	237	if (new_inode) {
	238	struct page * new_page;
	239	struct sysv_dir_entry * new_de;
	240
	241	err = -ENOTEMPTY;
	242	if (dir_de && !sysv_empty_dir(new_inode))
	243	goto out_dir;
	244
	245	err = -ENOENT;
	246	new_de = sysv_find_entry(new_dentry, &new_page);
	247	if (!new_de)
	248	goto out_dir;
4e907c3d	249	inode_inc_link_count(old_inode);
1da177e4 LT	250	sysv_set_link(new_de, new_page, old_inode);
	251	new_inode->i_ctime = CURRENT_TIME_SEC;
	252	if (dir_de)
9a53c3a7	253	drop_nlink(new_inode);
4e907c3d	254	inode_dec_link_count(new_inode);
1da177e4 LT	255	} else {
	256	if (dir_de) {
	257	err = -EMLINK;
	258	if (new_dir->i_nlink >= SYSV_SB(new_dir->i_sb)->s_link_max)
	259	goto out_dir;
	260	}
4e907c3d	261	inode_inc_link_count(old_inode);
1da177e4 LT	262	err = sysv_add_link(new_dentry, old_inode);
1da177e4 LT	263	if (err) {
4e907c3d	264	inode_dec_link_count(old_inode);
1da177e4 LT	265	goto out_dir;
	266	}
	267	if (dir_de)
4e907c3d	268	inode_inc_link_count(new_dir);
1da177e4 LT	269	}
	270
	271	sysv_delete_entry(old_de, old_page);
4e907c3d	272	inode_dec_link_count(old_inode);
1da177e4 LT	273
	274	if (dir_de) {
	275	sysv_set_link(dir_de, dir_page, new_dir);
4e907c3d	276	inode_dec_link_count(old_dir);
1da177e4 LT	277	}
	278	return 0;
	279
	280	out_dir:
	281	if (dir_de) {
	282	kunmap(dir_page);
	283	page_cache_release(dir_page);
	284	}
	285	out_old:
	286	kunmap(old_page);
	287	page_cache_release(old_page);
	288	out:
	289	return err;
	290	}
	291
	292	/*
	293	* directories can handle most operations...
	294	*/
	295	struct inode_operations sysv_dir_inode_operations = {
	296	.create = sysv_create,
	297	.lookup = sysv_lookup,
	298	.link = sysv_link,
	299	.unlink = sysv_unlink,
	300	.symlink = sysv_symlink,
	301	.mkdir = sysv_mkdir,
	302	.rmdir = sysv_rmdir,
	303	.mknod = sysv_mknod,
	304	.rename = sysv_rename,
	305	.getattr = sysv_getattr,
	306	};