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

/*
 * OMFS (as used by RIO Karma) directory operations.
 * Copyright (C) 2005 Bob Copeland <me@bobcopeland.com>
 * 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 block = clus_to_blk(OMFS_SB(dir->i_sb), dir->i_ino);
	int bucket = omfs_hash(name, namelen, nbuckets);

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

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 = sb_bread(dir->i_sb,
			clus_to_blk(OMFS_SB(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);
	int block = clus_to_blk(sbi, inode->i_ino);
	struct buffer_head *bh;
	struct omfs_inode *oi;

	bh = sb_bread(sb, block);
	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 = sb_bread(dir->i_sb, clus_to_blk(OMFS_SB(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 = sb_bread(dir->i_sb,
			clus_to_blk(OMFS_SB(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 = sb_bread(inode->i_sb, clus_to_blk(OMFS_SB(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 = sb_bread(dir->i_sb, clus_to_blk(OMFS_SB(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;
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 = sb_bread(dir->i_sb, clus_to_blk(OMFS_SB(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;
}

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

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 <me@bobcopeland.com>
	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;
	28	int block = clus_to_blk(OMFS_SB(dir->i_sb), dir->i_ino);
	29	int bucket = omfs_hash(name, namelen, nbuckets);
	30
	31	ofs = OMFS_DIR_START + bucket 8;
	32	return sb_bread(dir->i_sb, block);
	33	}
	34
	35	static struct buffer_head omfs_scan_list(struct inode dir, u64 block,
	36	const char *name, int namelen,
	37	u64 *prev_block)
	38	{
	39	struct buffer_head *bh;
	40	struct omfs_inode *oi;
	41	int err = -ENOENT;
	42	*prev_block = ~0;
	43
	44	while (block != ~0) {
	45	bh = sb_bread(dir->i_sb,
	46	clus_to_blk(OMFS_SB(dir->i_sb), block));
	47	if (!bh) {
	48	err = -EIO;
	49	goto err;
	50	}
	51
	52	oi = (struct omfs_inode *) bh->b_data;
	53	if (omfs_is_bad(OMFS_SB(dir->i_sb), &oi->i_head, block)) {
	54	brelse(bh);
	55	goto err;
	56	}
	57
	58	if (strncmp(oi->i_name, name, namelen) == 0)
	59	return bh;
	60
	61	*prev_block = block;
	62	block = be64_to_cpu(oi->i_sibling);
	63	brelse(bh);
	64	}
65	err:
66	return ERR_PTR(err);
67	}
68
69	static struct buffer_head omfs_find_entry(struct inode dir,
70	const char *name, int namelen)
71	{
72	struct buffer_head *bh;
73	int ofs;
74	u64 block, dummy;
75
76	bh = omfs_get_bucket(dir, name, namelen, &ofs);
77	if (!bh)
78	return ERR_PTR(-EIO);
79
80	block = be64_to_cpu(((__be64 ) &bh->b_data[ofs]));
81	brelse(bh);
82
83	return omfs_scan_list(dir, block, name, namelen, &dummy);
84	}
85
86	int omfs_make_empty(struct inode inode, struct super_block sb)
87	{
88	struct omfs_sb_info *sbi = OMFS_SB(sb);
89	int block = clus_to_blk(sbi, inode->i_ino);
90	struct buffer_head *bh;
91	struct omfs_inode *oi;
92
93	bh = sb_bread(sb, block);
94	if (!bh)
95	return -ENOMEM;
96
97	memset(bh->b_data, 0, sizeof(struct omfs_inode));
98
99	if (inode->i_mode & S_IFDIR) {
100	memset(&bh->b_data[OMFS_DIR_START], 0xff,
101	sbi->s_sys_blocksize - OMFS_DIR_START);
102	} else
103	omfs_make_empty_table(bh, OMFS_EXTENT_START);
104
105	oi = (struct omfs_inode *) bh->b_data;
106	oi->i_head.h_self = cpu_to_be64(inode->i_ino);
d406f66d	107	oi->i_sibling = ~cpu_to_be64(0ULL);
a3ab7155 BC	108
	109	mark_buffer_dirty(bh);
	110	brelse(bh);
	111	return 0;
	112	}
	113
	114	static int omfs_add_link(struct dentry dentry, struct inode inode)
	115	{
	116	struct inode *dir = dentry->d_parent->d_inode;
	117	const char *name = dentry->d_name.name;
	118	int namelen = dentry->d_name.len;
	119	struct omfs_inode *oi;
	120	struct buffer_head *bh;
	121	u64 block;
	122	__be64 *entry;
	123	int ofs;
	124
	125	/* just prepend to head of queue in proper bucket */
	126	bh = omfs_get_bucket(dir, name, namelen, &ofs);
	127	if (!bh)
	128	goto out;
	129
	130	entry = (__be64 *) &bh->b_data[ofs];
	131	block = be64_to_cpu(*entry);
	132	*entry = cpu_to_be64(inode->i_ino);
	133	mark_buffer_dirty(bh);
	134	brelse(bh);
	135
	136	/* now set the sibling and parent pointers on the new inode */
	137	bh = sb_bread(dir->i_sb, clus_to_blk(OMFS_SB(dir->i_sb), inode->i_ino));
	138	if (!bh)
	139	goto out;
	140
	141	oi = (struct omfs_inode *) bh->b_data;
	142	memcpy(oi->i_name, name, namelen);
	143	memset(oi->i_name + namelen, 0, OMFS_NAMELEN - namelen);
	144	oi->i_sibling = cpu_to_be64(block);
	145	oi->i_parent = cpu_to_be64(dir->i_ino);
	146	mark_buffer_dirty(bh);
	147	brelse(bh);
	148
	149	dir->i_ctime = CURRENT_TIME_SEC;
	150
	151	/* mark affected inodes dirty to rebuild checksums */
	152	mark_inode_dirty(dir);
	153	mark_inode_dirty(inode);
	154	return 0;
	155	out:
	156	return -ENOMEM;
	157	}
	158
	159	static int omfs_delete_entry(struct dentry *dentry)
	160	{
	161	struct inode *dir = dentry->d_parent->d_inode;
	162	struct inode *dirty;
	163	const char *name = dentry->d_name.name;
	164	int namelen = dentry->d_name.len;
	165	struct omfs_inode *oi;
	166	struct buffer_head bh, bh2;
	167	__be64 *entry, next;
	168	u64 block, prev;
	169	int ofs;
	170	int err = -ENOMEM;
	171
172	/* delete the proper node in the bucket's linked list */
173	bh = omfs_get_bucket(dir, name, namelen, &ofs);
174	if (!bh)
175	goto out;
176
177	entry = (__be64 *) &bh->b_data[ofs];
178	block = be64_to_cpu(*entry);
179
180	bh2 = omfs_scan_list(dir, block, name, namelen, &prev);
181	if (IS_ERR(bh2)) {
182	err = PTR_ERR(bh2);
183	goto out_free_bh;
184	}
185
186	oi = (struct omfs_inode *) bh2->b_data;
187	next = oi->i_sibling;
188	brelse(bh2);
189
190	if (prev != ~0) {
191	/* found in middle of list, get list ptr */
192	brelse(bh);
193	bh = sb_bread(dir->i_sb,
194	clus_to_blk(OMFS_SB(dir->i_sb), prev));
195	if (!bh)
196	goto out;
197
198	oi = (struct omfs_inode *) bh->b_data;
199	entry = &oi->i_sibling;
200	}
201
202	*entry = next;
203	mark_buffer_dirty(bh);
204
205	if (prev != ~0) {
206	dirty = omfs_iget(dir->i_sb, prev);
207	if (!IS_ERR(dirty)) {
208	mark_inode_dirty(dirty);
209	iput(dirty);
210	}
211	}
212
213	err = 0;
214	out_free_bh:
215	brelse(bh);
216	out:
217	return err;
218	}
219
220	static int omfs_dir_is_empty(struct inode *inode)
221	{
222	int nbuckets = (inode->i_size - OMFS_DIR_START) / 8;
223	struct buffer_head *bh;
224	u64 *ptr;
225	int i;
226
227	bh = sb_bread(inode->i_sb, clus_to_blk(OMFS_SB(inode->i_sb),
228	inode->i_ino));
229
230	if (!bh)
231	return 0;
232
233	ptr = (u64 *) &bh->b_data[OMFS_DIR_START];
234
235	for (i = 0; i < nbuckets; i++, ptr++)
236	if (*ptr != ~0)
237	break;
238
239	brelse(bh);
240	return *ptr != ~0;
241	}
242
243	static int omfs_unlink(struct inode dir, struct dentry dentry)
244	{
245	int ret;
246	struct inode *inode = dentry->d_inode;
247
248	ret = omfs_delete_entry(dentry);
249	if (ret)
250	goto end_unlink;
251
252	inode_dec_link_count(inode);
253	mark_inode_dirty(dir);
254
255	end_unlink:
256	return ret;
257	}
258
259	static int omfs_rmdir(struct inode dir, struct dentry dentry)
260	{
261	int err = -ENOTEMPTY;
262	struct inode *inode = dentry->d_inode;
263
264	if (omfs_dir_is_empty(inode)) {
265	err = omfs_unlink(dir, dentry);
266	if (!err)
267	inode_dec_link_count(inode);
268	}
269	return err;
270	}
271
272	static int omfs_add_node(struct inode dir, struct dentry dentry, int mode)
273	{
274	int err;
275	struct inode *inode = omfs_new_inode(dir, mode);
276
277	if (IS_ERR(inode))
278	return PTR_ERR(inode);
279
280	err = omfs_make_empty(inode, dir->i_sb);
281	if (err)
282	goto out_free_inode;
283
284	err = omfs_add_link(dentry, inode);
285	if (err)
286	goto out_free_inode;
287
288	d_instantiate(dentry, inode);
289	return 0;
290
291	out_free_inode:
292	iput(inode);
293	return err;
294	}
295
296	static int omfs_mkdir(struct inode dir, struct dentry dentry, int mode)
297	{
298	return omfs_add_node(dir, dentry, mode \| S_IFDIR);
299	}
300
301	static int omfs_create(struct inode dir, struct dentry dentry, int mode,
302	struct nameidata *nd)
303	{
304	return omfs_add_node(dir, dentry, mode \| S_IFREG);
305	}
306
307	static struct dentry omfs_lookup(struct inode dir, struct dentry *dentry,
308	struct nameidata *nd)
309	{
310	struct buffer_head *bh;
311	struct inode *inode = NULL;
312
313	if (dentry->d_name.len > OMFS_NAMELEN)
314	return ERR_PTR(-ENAMETOOLONG);
315
316	bh = omfs_find_entry(dir, dentry->d_name.name, dentry->d_name.len);
317	if (!IS_ERR(bh)) {
318	struct omfs_inode oi = (struct omfs_inode )bh->b_data;
319	ino_t ino = be64_to_cpu(oi->i_head.h_self);
320	brelse(bh);
321	inode = omfs_iget(dir->i_sb, ino);
322	if (IS_ERR(inode))
323	return ERR_CAST(inode);
324	}
325	d_add(dentry, inode);
326	return NULL;
327	}
328
329	/* sanity check block's self pointer */
330	int omfs_is_bad(struct omfs_sb_info sbi, struct omfs_header header,
331	u64 fsblock)
332	{
333	int is_bad;
334	u64 ino = be64_to_cpu(header->h_self);
335	is_bad = ((ino != fsblock) \|\| (ino < sbi->s_root_ino) \|\|
336	(ino > sbi->s_num_blocks));
337
338	if (is_bad)
339	printk(KERN_WARNING "omfs: bad hash chain detected\n");
340
341	return is_bad;
342	}
343
344	static int omfs_fill_chain(struct file filp, void dirent, filldir_t filldir,
345	u64 fsblock, int hindex)
346	{
347	struct inode *dir = filp->f_dentry->d_inode;
348	struct buffer_head *bh;
349	struct omfs_inode *oi;
350	u64 self;
351	int res = 0;
352	unsigned char d_type;
353
354	/* follow chain in this bucket */
355	while (fsblock != ~0) {
356	bh = sb_bread(dir->i_sb, clus_to_blk(OMFS_SB(dir->i_sb),
357	fsblock));
358	if (!bh)
359	goto out;
360
361	oi = (struct omfs_inode *) bh->b_data;
362	if (omfs_is_bad(OMFS_SB(dir->i_sb), &oi->i_head, fsblock)) {
363	brelse(bh);
364	goto out;
365	}
366
367	self = fsblock;
368	fsblock = be64_to_cpu(oi->i_sibling);
369
370	/* skip visited nodes */
371	if (hindex) {
372	hindex--;
373	brelse(bh);
374	continue;
375	}
376
377	d_type = (oi->i_type == OMFS_DIR) ? DT_DIR : DT_REG;
378
379	res = filldir(dirent, oi->i_name, strnlen(oi->i_name,
380	OMFS_NAMELEN), filp->f_pos, self, d_type);
381	if (res == 0)
382	filp->f_pos++;
383	brelse(bh);
384	}
385	out:
386	return res;
387	}
388
389	static int omfs_rename(struct inode old_dir, struct dentry old_dentry,
390	struct inode new_dir, struct dentry new_dentry)
391	{
392	struct inode *new_inode = new_dentry->d_inode;
393	struct inode *old_inode = old_dentry->d_inode;
394	struct buffer_head *bh;
395	int is_dir;
396	int err;
397
398	is_dir = S_ISDIR(old_inode->i_mode);
399
400	if (new_inode) {
401	/* overwriting existing file/dir */
402	err = -ENOTEMPTY;
403	if (is_dir && !omfs_dir_is_empty(new_inode))
404	goto out;
405
406	err = -ENOENT;
407	bh = omfs_find_entry(new_dir, new_dentry->d_name.name,
408	new_dentry->d_name.len);
409	if (IS_ERR(bh))
410	goto out;
411	brelse(bh);
412
413	err = omfs_unlink(new_dir, new_dentry);
414	if (err)
415	goto out;
416	}
417
418	/* since omfs locates files by name, we need to unlink _before_
419	* adding the new link or we won't find the old one */
420	inode_inc_link_count(old_inode);
421	err = omfs_unlink(old_dir, old_dentry);
422	if (err) {
423	inode_dec_link_count(old_inode);
424	goto out;
425	}
426
427	err = omfs_add_link(new_dentry, old_inode);
428	if (err)
429	goto out;
430
431	old_inode->i_ctime = CURRENT_TIME_SEC;
432	out:
433	return err;
434	}
435
436	static int omfs_readdir(struct file filp, void dirent, filldir_t filldir)
437	{
438	struct inode *dir = filp->f_dentry->d_inode;
439	struct buffer_head *bh;
440	loff_t offset, res;
441	unsigned int hchain, hindex;
442	int nbuckets;
443	u64 fsblock;
444	int ret = -EINVAL;
445
446	if (filp->f_pos >> 32)
447	goto success;
448
449	switch ((unsigned long) filp->f_pos) {
450	case 0:
451	if (filldir(dirent, ".", 1, 0, dir->i_ino, DT_DIR) < 0)
452	goto success;
453	filp->f_pos++;
454	/* fall through */
455	case 1:
456	if (filldir(dirent, "..", 2, 1,
457	parent_ino(filp->f_dentry), DT_DIR) < 0)
458	goto success;
459	filp->f_pos = 1 << 20;
460	/* fall through */
461	}
462
463	nbuckets = (dir->i_size - OMFS_DIR_START) / 8;
464
465	/* high 12 bits store bucket + 1 and low 20 bits store hash index */
466	hchain = (filp->f_pos >> 20) - 1;
467	hindex = filp->f_pos & 0xfffff;
468
469	bh = sb_bread(dir->i_sb, clus_to_blk(OMFS_SB(dir->i_sb), dir->i_ino));
470	if (!bh)
471	goto out;
472
473	offset = OMFS_DIR_START + hchain * 8;
474
475	for (; hchain < nbuckets; hchain++, offset += 8) {
476	fsblock = be64_to_cpu(((__be64 ) &bh->b_data[offset]));
477
478	res = omfs_fill_chain(filp, dirent, filldir, fsblock, hindex);
479	hindex = 0;
480	if (res < 0)
481	break;
482
483	filp->f_pos = (hchain+2) << 20;
484	}
485	brelse(bh);
486	success:
487	ret = 0;
488	out:
489	return ret;
490	}
491
492	struct inode_operations omfs_dir_inops = {
493	.lookup = omfs_lookup,
494	.mkdir = omfs_mkdir,
495	.rename = omfs_rename,
496	.create = omfs_create,
497	.unlink = omfs_unlink,
498	.rmdir = omfs_rmdir,
499	};
500
501	struct file_operations omfs_dir_operations = {
502	.read = generic_read_dir,
503	.readdir = omfs_readdir,
3222a3e5	504	.llseek = generic_file_llseek,
a3ab7155	505	};