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

/*
 * OMFS (as used by RIO Karma) directory operations.
 * Copyright (C) 2005 Bob Copeland <[email protected]>
 * Released under GPL v2.
 */

#include <linux/fs.h>
#include <linux/ctype.h>
#include <linux/buffer_head.h>
#include "omfs.h"

static int omfs_hash(const char *name, int namelen, int mod)
{
	int i, hash = 0;
	for (i = 0; i < namelen; i++)
		hash ^= tolower(name[i]) << (i % 24);
	return hash % mod;
}

/*
 * Finds the bucket for a given name and reads the containing block;
 * *ofs is set to the offset of the first list entry.
 */
static struct buffer_head *omfs_get_bucket(struct inode *dir,
		const char *name, int namelen, int *ofs)
{
	int nbuckets = (dir->i_size - OMFS_DIR_START)/8;
	int bucket = omfs_hash(name, namelen, nbuckets);

	*ofs = OMFS_DIR_START + bucket * 8;
	return omfs_bread(dir->i_sb, dir->i_ino);
}

static struct buffer_head *omfs_scan_list(struct inode *dir, u64 block,
				const char *name, int namelen,
				u64 *prev_block)
{
	struct buffer_head *bh;
	struct omfs_inode *oi;
	int err = -ENOENT;
	*prev_block = ~0;

	while (block != ~0) {
		bh = omfs_bread(dir->i_sb, block);
		if (!bh) {
			err = -EIO;
			goto err;
		}

		oi = (struct omfs_inode *) bh->b_data;
		if (omfs_is_bad(OMFS_SB(dir->i_sb), &oi->i_head, block)) {
			brelse(bh);
			goto err;
		}

		if (strncmp(oi->i_name, name, namelen) == 0)
			return bh;

		*prev_block = block;
		block = be64_to_cpu(oi->i_sibling);
		brelse(bh);
	}
err:
	return ERR_PTR(err);
}

static struct buffer_head *omfs_find_entry(struct inode *dir,
					   const char *name, int namelen)
{
	struct buffer_head *bh;
	int ofs;
	u64 block, dummy;

	bh = omfs_get_bucket(dir, name, namelen, &ofs);
	if (!bh)
		return ERR_PTR(-EIO);

	block = be64_to_cpu(*((__be64 *) &bh->b_data[ofs]));
	brelse(bh);

	return omfs_scan_list(dir, block, name, namelen, &dummy);
}

int omfs_make_empty(struct inode *inode, struct super_block *sb)
{
	struct omfs_sb_info *sbi = OMFS_SB(sb);
	struct buffer_head *bh;
	struct omfs_inode *oi;

	bh = omfs_bread(sb, inode->i_ino);
	if (!bh)
		return -ENOMEM;

	memset(bh->b_data, 0, sizeof(struct omfs_inode));

	if (inode->i_mode & S_IFDIR) {
		memset(&bh->b_data[OMFS_DIR_START], 0xff,
			sbi->s_sys_blocksize - OMFS_DIR_START);
	} else
		omfs_make_empty_table(bh, OMFS_EXTENT_START);

	oi = (struct omfs_inode *) bh->b_data;
	oi->i_head.h_self = cpu_to_be64(inode->i_ino);
	oi->i_sibling = ~cpu_to_be64(0ULL);

	mark_buffer_dirty(bh);
	brelse(bh);
	return 0;
}

static int omfs_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 omfs_inode *oi;
	struct buffer_head *bh;
	u64 block;
	__be64 *entry;
	int ofs;

	/* just prepend to head of queue in proper bucket */
	bh = omfs_get_bucket(dir, name, namelen, &ofs);
	if (!bh)
		goto out;

	entry = (__be64 *) &bh->b_data[ofs];
	block = be64_to_cpu(*entry);
	*entry = cpu_to_be64(inode->i_ino);
	mark_buffer_dirty(bh);
	brelse(bh);

	/* now set the sibling and parent pointers on the new inode */
	bh = omfs_bread(dir->i_sb, inode->i_ino);
	if (!bh)
		goto out;

	oi = (struct omfs_inode *) bh->b_data;
	memcpy(oi->i_name, name, namelen);
	memset(oi->i_name + namelen, 0, OMFS_NAMELEN - namelen);
	oi->i_sibling = cpu_to_be64(block);
	oi->i_parent = cpu_to_be64(dir->i_ino);
	mark_buffer_dirty(bh);
	brelse(bh);

	dir->i_ctime = CURRENT_TIME_SEC;

	/* mark affected inodes dirty to rebuild checksums */
	mark_inode_dirty(dir);
	mark_inode_dirty(inode);
	return 0;
out:
	return -ENOMEM;
}

static int omfs_delete_entry(struct dentry *dentry)
{
	struct inode *dir = dentry->d_parent->d_inode;
	struct inode *dirty;
	const char *name = dentry->d_name.name;
	int namelen = dentry->d_name.len;
	struct omfs_inode *oi;
	struct buffer_head *bh, *bh2;
	__be64 *entry, next;
	u64 block, prev;
	int ofs;
	int err = -ENOMEM;

	/* delete the proper node in the bucket's linked list */
	bh = omfs_get_bucket(dir, name, namelen, &ofs);
	if (!bh)
		goto out;

	entry = (__be64 *) &bh->b_data[ofs];
	block = be64_to_cpu(*entry);

	bh2 = omfs_scan_list(dir, block, name, namelen, &prev);
	if (IS_ERR(bh2)) {
		err = PTR_ERR(bh2);
		goto out_free_bh;
	}

	oi = (struct omfs_inode *) bh2->b_data;
	next = oi->i_sibling;
	brelse(bh2);

	if (prev != ~0) {
		/* found in middle of list, get list ptr */
		brelse(bh);
		bh = omfs_bread(dir->i_sb, prev);
		if (!bh)
			goto out;

		oi = (struct omfs_inode *) bh->b_data;
		entry = &oi->i_sibling;
	}

	*entry = next;
	mark_buffer_dirty(bh);

	if (prev != ~0) {
		dirty = omfs_iget(dir->i_sb, prev);
		if (!IS_ERR(dirty)) {
			mark_inode_dirty(dirty);
			iput(dirty);
		}
	}

	err = 0;
out_free_bh:
	brelse(bh);
out:
	return err;
}

static int omfs_dir_is_empty(struct inode *inode)
{
	int nbuckets = (inode->i_size - OMFS_DIR_START) / 8;
	struct buffer_head *bh;
	u64 *ptr;
	int i;

	bh = omfs_bread(inode->i_sb, inode->i_ino);

	if (!bh)
		return 0;

	ptr = (u64 *) &bh->b_data[OMFS_DIR_START];

	for (i = 0; i < nbuckets; i++, ptr++)
		if (*ptr != ~0)
			break;

	brelse(bh);
	return *ptr != ~0;
}

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

	ret = omfs_delete_entry(dentry);
	if (ret)
		goto end_unlink;

	inode_dec_link_count(inode);
	mark_inode_dirty(dir);

end_unlink:
	return ret;
}

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

	if (omfs_dir_is_empty(inode)) {
		err = omfs_unlink(dir, dentry);
		if (!err)
			inode_dec_link_count(inode);
	}
	return err;
}

static int omfs_add_node(struct inode *dir, struct dentry *dentry, int mode)
{
	int err;
	struct inode *inode = omfs_new_inode(dir, mode);

	if (IS_ERR(inode))
		return PTR_ERR(inode);

	err = omfs_make_empty(inode, dir->i_sb);
	if (err)
		goto out_free_inode;

	err = omfs_add_link(dentry, inode);
	if (err)
		goto out_free_inode;

	d_instantiate(dentry, inode);
	return 0;

out_free_inode:
	iput(inode);
	return err;
}

static int omfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
{
	return omfs_add_node(dir, dentry, mode | S_IFDIR);
}

static int omfs_create(struct inode *dir, struct dentry *dentry, int mode,
		struct nameidata *nd)
{
	return omfs_add_node(dir, dentry, mode | S_IFREG);
}

static struct dentry *omfs_lookup(struct inode *dir, struct dentry *dentry,
				  struct nameidata *nd)
{
	struct buffer_head *bh;
	struct inode *inode = NULL;

	if (dentry->d_name.len > OMFS_NAMELEN)
		return ERR_PTR(-ENAMETOOLONG);

	bh = omfs_find_entry(dir, dentry->d_name.name, dentry->d_name.len);
	if (!IS_ERR(bh)) {
		struct omfs_inode *oi = (struct omfs_inode *)bh->b_data;
		ino_t ino = be64_to_cpu(oi->i_head.h_self);
		brelse(bh);
		inode = omfs_iget(dir->i_sb, ino);
		if (IS_ERR(inode))
			return ERR_CAST(inode);
	}
	d_add(dentry, inode);
	return NULL;
}

/* sanity check block's self pointer */
int omfs_is_bad(struct omfs_sb_info *sbi, struct omfs_header *header,
	u64 fsblock)
{
	int is_bad;
	u64 ino = be64_to_cpu(header->h_self);
	is_bad = ((ino != fsblock) || (ino < sbi->s_root_ino) ||
		(ino > sbi->s_num_blocks));

	if (is_bad)
		printk(KERN_WARNING "omfs: bad hash chain detected\n");

	return is_bad;
}

static int omfs_fill_chain(struct file *filp, void *dirent, filldir_t filldir,
		u64 fsblock, int hindex)
{
	struct inode *dir = filp->f_dentry->d_inode;
	struct buffer_head *bh;
	struct omfs_inode *oi;
	u64 self;
	int res = 0;
	unsigned char d_type;

	/* follow chain in this bucket */
	while (fsblock != ~0) {
		bh = omfs_bread(dir->i_sb, fsblock);
		if (!bh)
			goto out;

		oi = (struct omfs_inode *) bh->b_data;
		if (omfs_is_bad(OMFS_SB(dir->i_sb), &oi->i_head, fsblock)) {
			brelse(bh);
			goto out;
		}

		self = fsblock;
		fsblock = be64_to_cpu(oi->i_sibling);

		/* skip visited nodes */
		if (hindex) {
			hindex--;
			brelse(bh);
			continue;
		}

		d_type = (oi->i_type == OMFS_DIR) ? DT_DIR : DT_REG;

		res = filldir(dirent, oi->i_name, strnlen(oi->i_name,
			OMFS_NAMELEN), filp->f_pos, self, d_type);
		if (res == 0)
			filp->f_pos++;
		brelse(bh);
	}
out:
	return res;
}

static int omfs_rename(struct inode *old_dir, struct dentry *old_dentry,
		struct inode *new_dir, struct dentry *new_dentry)
{
	struct inode *new_inode = new_dentry->d_inode;
	struct inode *old_inode = old_dentry->d_inode;
	struct buffer_head *bh;
	int is_dir;
	int err;

	is_dir = S_ISDIR(old_inode->i_mode);

	if (new_inode) {
		/* overwriting existing file/dir */
		err = -ENOTEMPTY;
		if (is_dir && !omfs_dir_is_empty(new_inode))
			goto out;

		err = -ENOENT;
		bh = omfs_find_entry(new_dir, new_dentry->d_name.name,
			new_dentry->d_name.len);
		if (IS_ERR(bh))
			goto out;
		brelse(bh);

		err = omfs_unlink(new_dir, new_dentry);
		if (err)
			goto out;
	}

	/* since omfs locates files by name, we need to unlink _before_
	 * adding the new link or we won't find the old one */
	inode_inc_link_count(old_inode);
	err = omfs_unlink(old_dir, old_dentry);
	if (err) {
		inode_dec_link_count(old_inode);
		goto out;
	}

	err = omfs_add_link(new_dentry, old_inode);
	if (err)
		goto out;

	old_inode->i_ctime = CURRENT_TIME_SEC;
	mark_inode_dirty(old_inode);
out:
	return err;
}

static int omfs_readdir(struct file *filp, void *dirent, filldir_t filldir)
{
	struct inode *dir = filp->f_dentry->d_inode;
	struct buffer_head *bh;
	loff_t offset, res;
	unsigned int hchain, hindex;
	int nbuckets;
	u64 fsblock;
	int ret = -EINVAL;

	if (filp->f_pos >> 32)
		goto success;

	switch ((unsigned long) filp->f_pos) {
	case 0:
		if (filldir(dirent, ".", 1, 0, dir->i_ino, DT_DIR) < 0)
			goto success;
		filp->f_pos++;
		/* fall through */
	case 1:
		if (filldir(dirent, "..", 2, 1,
		    parent_ino(filp->f_dentry), DT_DIR) < 0)
			goto success;
		filp->f_pos = 1 << 20;
		/* fall through */
	}

	nbuckets = (dir->i_size - OMFS_DIR_START) / 8;

	/* high 12 bits store bucket + 1 and low 20 bits store hash index */
	hchain = (filp->f_pos >> 20) - 1;
	hindex = filp->f_pos & 0xfffff;

	bh = omfs_bread(dir->i_sb, dir->i_ino);
	if (!bh)
		goto out;

	offset = OMFS_DIR_START + hchain * 8;

	for (; hchain < nbuckets; hchain++, offset += 8) {
		fsblock = be64_to_cpu(*((__be64 *) &bh->b_data[offset]));

		res = omfs_fill_chain(filp, dirent, filldir, fsblock, hindex);
		hindex = 0;
		if (res < 0)
			break;

		filp->f_pos = (hchain+2) << 20;
	}
	brelse(bh);
success:
	ret = 0;
out:
	return ret;
}

const struct inode_operations omfs_dir_inops = {
	.lookup = omfs_lookup,
	.mkdir = omfs_mkdir,
	.rename = omfs_rename,
	.create = omfs_create,
	.unlink = omfs_unlink,
	.rmdir = omfs_rmdir,
};

const struct file_operations omfs_dir_operations = {
	.read = generic_read_dir,
	.readdir = omfs_readdir,
	.llseek = generic_file_llseek,
};
Commit	Line	Data
a3ab7155 BC	1	/*
	2	* OMFS (as used by RIO Karma) directory operations.
	3	* Copyright (C) 2005 Bob Copeland <[email protected]>
	4	* Released under GPL v2.
	5	*/
	6
	7	#include <linux/fs.h>
	8	#include <linux/ctype.h>
	9	#include <linux/buffer_head.h>
	10	#include "omfs.h"
	11
	12	static int omfs_hash(const char *name, int namelen, int mod)
	13	{
	14	int i, hash = 0;
	15	for (i = 0; i < namelen; i++)
	16	hash ^= tolower(name[i]) << (i % 24);
	17	return hash % mod;
	18	}
	19
	20	/*
	21	* Finds the bucket for a given name and reads the containing block;
	22	* *ofs is set to the offset of the first list entry.
	23	*/
	24	static struct buffer_head omfs_get_bucket(struct inode dir,
	25	const char name, int namelen, int ofs)
	26	{
	27	int nbuckets = (dir->i_size - OMFS_DIR_START)/8;
a3ab7155 BC	28	int bucket = omfs_hash(name, namelen, nbuckets);
	29
	30	ofs = OMFS_DIR_START + bucket 8;
f068272c	31	return omfs_bread(dir->i_sb, dir->i_ino);
a3ab7155 BC	32	}
	33
	34	static struct buffer_head omfs_scan_list(struct inode dir, u64 block,
	35	const char *name, int namelen,
	36	u64 *prev_block)
	37	{
	38	struct buffer_head *bh;
	39	struct omfs_inode *oi;
	40	int err = -ENOENT;
	41	*prev_block = ~0;
	42
	43	while (block != ~0) {
f068272c	44	bh = omfs_bread(dir->i_sb, block);
a3ab7155 BC	45	if (!bh) {
	46	err = -EIO;
	47	goto err;
	48	}
	49
	50	oi = (struct omfs_inode *) bh->b_data;
	51	if (omfs_is_bad(OMFS_SB(dir->i_sb), &oi->i_head, block)) {
	52	brelse(bh);
	53	goto err;
	54	}
	55
	56	if (strncmp(oi->i_name, name, namelen) == 0)
	57	return bh;
	58
	59	*prev_block = block;
	60	block = be64_to_cpu(oi->i_sibling);
	61	brelse(bh);
	62	}
	63	err:
	64	return ERR_PTR(err);
	65	}
	66
	67	static struct buffer_head omfs_find_entry(struct inode dir,
	68	const char *name, int namelen)
	69	{
	70	struct buffer_head *bh;
	71	int ofs;
	72	u64 block, dummy;
	73
	74	bh = omfs_get_bucket(dir, name, namelen, &ofs);
	75	if (!bh)
	76	return ERR_PTR(-EIO);
	77
	78	block = be64_to_cpu(((__be64 ) &bh->b_data[ofs]));
	79	brelse(bh);
	80
	81	return omfs_scan_list(dir, block, name, namelen, &dummy);
	82	}
	83
	84	int omfs_make_empty(struct inode inode, struct super_block sb)
	85	{
	86	struct omfs_sb_info *sbi = OMFS_SB(sb);
a3ab7155 BC	87	struct buffer_head *bh;
	88	struct omfs_inode *oi;
	89
f068272c	90	bh = omfs_bread(sb, inode->i_ino);
a3ab7155 BC	91	if (!bh)
	92	return -ENOMEM;
	93
	94	memset(bh->b_data, 0, sizeof(struct omfs_inode));
	95
	96	if (inode->i_mode & S_IFDIR) {
	97	memset(&bh->b_data[OMFS_DIR_START], 0xff,
	98	sbi->s_sys_blocksize - OMFS_DIR_START);
	99	} else
	100	omfs_make_empty_table(bh, OMFS_EXTENT_START);
	101
	102	oi = (struct omfs_inode *) bh->b_data;
	103	oi->i_head.h_self = cpu_to_be64(inode->i_ino);
d406f66d	104	oi->i_sibling = ~cpu_to_be64(0ULL);
a3ab7155 BC	105
	106	mark_buffer_dirty(bh);
	107	brelse(bh);
	108	return 0;
	109	}
	110
	111	static int omfs_add_link(struct dentry dentry, struct inode inode)
	112	{
	113	struct inode *dir = dentry->d_parent->d_inode;
	114	const char *name = dentry->d_name.name;
	115	int namelen = dentry->d_name.len;
	116	struct omfs_inode *oi;
	117	struct buffer_head *bh;
	118	u64 block;
	119	__be64 *entry;
	120	int ofs;
	121
	122	/* just prepend to head of queue in proper bucket */
	123	bh = omfs_get_bucket(dir, name, namelen, &ofs);
	124	if (!bh)
	125	goto out;
	126
	127	entry = (__be64 *) &bh->b_data[ofs];
	128	block = be64_to_cpu(*entry);
	129	*entry = cpu_to_be64(inode->i_ino);
	130	mark_buffer_dirty(bh);
	131	brelse(bh);
	132
	133	/* now set the sibling and parent pointers on the new inode */
f068272c	134	bh = omfs_bread(dir->i_sb, inode->i_ino);
a3ab7155 BC	135	if (!bh)
	136	goto out;
	137
	138	oi = (struct omfs_inode *) bh->b_data;
	139	memcpy(oi->i_name, name, namelen);
	140	memset(oi->i_name + namelen, 0, OMFS_NAMELEN - namelen);
	141	oi->i_sibling = cpu_to_be64(block);
	142	oi->i_parent = cpu_to_be64(dir->i_ino);
	143	mark_buffer_dirty(bh);
	144	brelse(bh);
	145
	146	dir->i_ctime = CURRENT_TIME_SEC;
	147
	148	/* mark affected inodes dirty to rebuild checksums */
	149	mark_inode_dirty(dir);
	150	mark_inode_dirty(inode);
	151	return 0;
	152	out:
	153	return -ENOMEM;
	154	}
	155
	156	static int omfs_delete_entry(struct dentry *dentry)
	157	{
	158	struct inode *dir = dentry->d_parent->d_inode;
	159	struct inode *dirty;
	160	const char *name = dentry->d_name.name;
	161	int namelen = dentry->d_name.len;
	162	struct omfs_inode *oi;
	163	struct buffer_head bh, bh2;
	164	__be64 *entry, next;
	165	u64 block, prev;
	166	int ofs;
	167	int err = -ENOMEM;
	168
	169	/* delete the proper node in the bucket's linked list */
	170	bh = omfs_get_bucket(dir, name, namelen, &ofs);
	171	if (!bh)
	172	goto out;
	173
	174	entry = (__be64 *) &bh->b_data[ofs];
	175	block = be64_to_cpu(*entry);
	176
	177	bh2 = omfs_scan_list(dir, block, name, namelen, &prev);
	178	if (IS_ERR(bh2)) {
	179	err = PTR_ERR(bh2);
	180	goto out_free_bh;
	181	}
	182
	183	oi = (struct omfs_inode *) bh2->b_data;
	184	next = oi->i_sibling;
	185	brelse(bh2);
	186
	187	if (prev != ~0) {
	188	/* found in middle of list, get list ptr */
	189	brelse(bh);
f068272c	190	bh = omfs_bread(dir->i_sb, prev);
a3ab7155 BC	191	if (!bh)
	192	goto out;
	193
	194	oi = (struct omfs_inode *) bh->b_data;
	195	entry = &oi->i_sibling;
	196	}
	197
	198	*entry = next;
	199	mark_buffer_dirty(bh);
	200
	201	if (prev != ~0) {
	202	dirty = omfs_iget(dir->i_sb, prev);
	203	if (!IS_ERR(dirty)) {
	204	mark_inode_dirty(dirty);
	205	iput(dirty);
	206	}
	207	}
	208
	209	err = 0;
	210	out_free_bh:
	211	brelse(bh);
	212	out:
	213	return err;
	214	}
	215
	216	static int omfs_dir_is_empty(struct inode *inode)
	217	{
	218	int nbuckets = (inode->i_size - OMFS_DIR_START) / 8;
	219	struct buffer_head *bh;
	220	u64 *ptr;
	221	int i;
	222
f068272c	223	bh = omfs_bread(inode->i_sb, inode->i_ino);
a3ab7155 BC	224
	225	if (!bh)
	226	return 0;
	227
	228	ptr = (u64 *) &bh->b_data[OMFS_DIR_START];
	229
	230	for (i = 0; i < nbuckets; i++, ptr++)
	231	if (*ptr != ~0)
	232	break;
	233
	234	brelse(bh);
	235	return *ptr != ~0;
	236	}
	237
	238	static int omfs_unlink(struct inode dir, struct dentry dentry)
	239	{
	240	int ret;
	241	struct inode *inode = dentry->d_inode;
	242
	243	ret = omfs_delete_entry(dentry);
	244	if (ret)
	245	goto end_unlink;
	246
	247	inode_dec_link_count(inode);
	248	mark_inode_dirty(dir);
	249
	250	end_unlink:
	251	return ret;
	252	}
	253
	254	static int omfs_rmdir(struct inode dir, struct dentry dentry)
	255	{
	256	int err = -ENOTEMPTY;
	257	struct inode *inode = dentry->d_inode;
	258
	259	if (omfs_dir_is_empty(inode)) {
	260	err = omfs_unlink(dir, dentry);
	261	if (!err)
	262	inode_dec_link_count(inode);
	263	}
	264	return err;
	265	}
	266
	267	static int omfs_add_node(struct inode dir, struct dentry dentry, int mode)
	268	{
	269	int err;
	270	struct inode *inode = omfs_new_inode(dir, mode);
	271
	272	if (IS_ERR(inode))
	273	return PTR_ERR(inode);
	274
	275	err = omfs_make_empty(inode, dir->i_sb);
	276	if (err)
	277	goto out_free_inode;
	278
	279	err = omfs_add_link(dentry, inode);
	280	if (err)
	281	goto out_free_inode;
	282
	283	d_instantiate(dentry, inode);
	284	return 0;
	285
	286	out_free_inode:
	287	iput(inode);
288	return err;
289	}
290
291	static int omfs_mkdir(struct inode dir, struct dentry dentry, int mode)
292	{
293	return omfs_add_node(dir, dentry, mode \| S_IFDIR);
294	}
295
296	static int omfs_create(struct inode dir, struct dentry dentry, int mode,
297	struct nameidata *nd)
298	{
299	return omfs_add_node(dir, dentry, mode \| S_IFREG);
300	}
301
302	static struct dentry omfs_lookup(struct inode dir, struct dentry *dentry,
303	struct nameidata *nd)
304	{
305	struct buffer_head *bh;
306	struct inode *inode = NULL;
307
308	if (dentry->d_name.len > OMFS_NAMELEN)
309	return ERR_PTR(-ENAMETOOLONG);
310
311	bh = omfs_find_entry(dir, dentry->d_name.name, dentry->d_name.len);
312	if (!IS_ERR(bh)) {
313	struct omfs_inode oi = (struct omfs_inode )bh->b_data;
314	ino_t ino = be64_to_cpu(oi->i_head.h_self);
315	brelse(bh);
316	inode = omfs_iget(dir->i_sb, ino);
317	if (IS_ERR(inode))
318	return ERR_CAST(inode);
319	}
320	d_add(dentry, inode);
321	return NULL;
322	}
323
324	/* sanity check block's self pointer */
325	int omfs_is_bad(struct omfs_sb_info sbi, struct omfs_header header,
326	u64 fsblock)
327	{
328	int is_bad;
329	u64 ino = be64_to_cpu(header->h_self);
330	is_bad = ((ino != fsblock) \|\| (ino < sbi->s_root_ino) \|\|
331	(ino > sbi->s_num_blocks));
332
333	if (is_bad)
334	printk(KERN_WARNING "omfs: bad hash chain detected\n");
335
336	return is_bad;
337	}
338
339	static int omfs_fill_chain(struct file filp, void dirent, filldir_t filldir,
340	u64 fsblock, int hindex)
341	{
342	struct inode *dir = filp->f_dentry->d_inode;
343	struct buffer_head *bh;
344	struct omfs_inode *oi;
345	u64 self;
346	int res = 0;
347	unsigned char d_type;
348
349	/* follow chain in this bucket */
350	while (fsblock != ~0) {
f068272c	351	bh = omfs_bread(dir->i_sb, fsblock);
a3ab7155 BC	352	if (!bh)
	353	goto out;
	354
	355	oi = (struct omfs_inode *) bh->b_data;
	356	if (omfs_is_bad(OMFS_SB(dir->i_sb), &oi->i_head, fsblock)) {
	357	brelse(bh);
	358	goto out;
	359	}
	360
	361	self = fsblock;
	362	fsblock = be64_to_cpu(oi->i_sibling);
	363
	364	/* skip visited nodes */
	365	if (hindex) {
	366	hindex--;
	367	brelse(bh);
	368	continue;
	369	}
	370
	371	d_type = (oi->i_type == OMFS_DIR) ? DT_DIR : DT_REG;
	372
	373	res = filldir(dirent, oi->i_name, strnlen(oi->i_name,
	374	OMFS_NAMELEN), filp->f_pos, self, d_type);
	375	if (res == 0)
	376	filp->f_pos++;
	377	brelse(bh);
	378	}
	379	out:
	380	return res;
	381	}
	382
	383	static int omfs_rename(struct inode old_dir, struct dentry old_dentry,
	384	struct inode new_dir, struct dentry new_dentry)
	385	{
	386	struct inode *new_inode = new_dentry->d_inode;
	387	struct inode *old_inode = old_dentry->d_inode;
	388	struct buffer_head *bh;
	389	int is_dir;
	390	int err;
	391
	392	is_dir = S_ISDIR(old_inode->i_mode);
	393
	394	if (new_inode) {
	395	/* overwriting existing file/dir */
	396	err = -ENOTEMPTY;
	397	if (is_dir && !omfs_dir_is_empty(new_inode))
	398	goto out;
	399
	400	err = -ENOENT;
	401	bh = omfs_find_entry(new_dir, new_dentry->d_name.name,
	402	new_dentry->d_name.len);
	403	if (IS_ERR(bh))
	404	goto out;
	405	brelse(bh);
	406
	407	err = omfs_unlink(new_dir, new_dentry);
	408	if (err)
	409	goto out;
	410	}
	411
	412	/* since omfs locates files by name, we need to unlink _before_
	413	* adding the new link or we won't find the old one */
	414	inode_inc_link_count(old_inode);
	415	err = omfs_unlink(old_dir, old_dentry);
416	if (err) {
417	inode_dec_link_count(old_inode);
418	goto out;
419	}
420
421	err = omfs_add_link(new_dentry, old_inode);
422	if (err)
423	goto out;
424
425	old_inode->i_ctime = CURRENT_TIME_SEC;
013e4f4a	426	mark_inode_dirty(old_inode);
a3ab7155 BC	427	out:
	428	return err;
	429	}
	430
	431	static int omfs_readdir(struct file filp, void dirent, filldir_t filldir)
	432	{
	433	struct inode *dir = filp->f_dentry->d_inode;
	434	struct buffer_head *bh;
	435	loff_t offset, res;
	436	unsigned int hchain, hindex;
	437	int nbuckets;
	438	u64 fsblock;
	439	int ret = -EINVAL;
	440
	441	if (filp->f_pos >> 32)
	442	goto success;
	443
	444	switch ((unsigned long) filp->f_pos) {
	445	case 0:
	446	if (filldir(dirent, ".", 1, 0, dir->i_ino, DT_DIR) < 0)
	447	goto success;
	448	filp->f_pos++;
	449	/* fall through */
	450	case 1:
	451	if (filldir(dirent, "..", 2, 1,
	452	parent_ino(filp->f_dentry), DT_DIR) < 0)
	453	goto success;
	454	filp->f_pos = 1 << 20;
	455	/* fall through */
	456	}
	457
	458	nbuckets = (dir->i_size - OMFS_DIR_START) / 8;
	459
	460	/* high 12 bits store bucket + 1 and low 20 bits store hash index */
	461	hchain = (filp->f_pos >> 20) - 1;
	462	hindex = filp->f_pos & 0xfffff;
	463
f068272c	464	bh = omfs_bread(dir->i_sb, dir->i_ino);
a3ab7155 BC	465	if (!bh)
	466	goto out;
	467
	468	offset = OMFS_DIR_START + hchain * 8;
	469
	470	for (; hchain < nbuckets; hchain++, offset += 8) {
	471	fsblock = be64_to_cpu(((__be64 ) &bh->b_data[offset]));
	472
	473	res = omfs_fill_chain(filp, dirent, filldir, fsblock, hindex);
	474	hindex = 0;
	475	if (res < 0)
	476	break;
	477
	478	filp->f_pos = (hchain+2) << 20;
	479	}
	480	brelse(bh);
	481	success:
	482	ret = 0;
	483	out:
	484	return ret;
	485	}
	486
6e1d5dcc	487	const struct inode_operations omfs_dir_inops = {
a3ab7155 BC	488	.lookup = omfs_lookup,
	489	.mkdir = omfs_mkdir,
	490	.rename = omfs_rename,
	491	.create = omfs_create,
	492	.unlink = omfs_unlink,
	493	.rmdir = omfs_rmdir,
	494	};
	495
828c0950	496	const struct file_operations omfs_dir_operations = {
a3ab7155 BC	497	.read = generic_read_dir,
a3ab7155 BC	498	.readdir = omfs_readdir,
3222a3e5	499	.llseek = generic_file_llseek,
a3ab7155	500	};