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

// SPDX-License-Identifier: GPL-2.0-only
/*
 * OMFS (as used by RIO Karma) directory operations.
 * Copyright (C) 2005 Bob Copeland <me@bobcopeland.com>
 */

#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 (S_ISDIR(inode->i_mode)) {
		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 = d_inode(dentry->d_parent);
	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(dir);

	/* 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 = d_inode(dentry->d_parent);
	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_remove(struct inode *dir, struct dentry *dentry)
{
	struct inode *inode = d_inode(dentry);
	int ret;


	if (S_ISDIR(inode->i_mode) &&
	    !omfs_dir_is_empty(inode))
		return -ENOTEMPTY;

	ret = omfs_delete_entry(dentry);
	if (ret)
		return ret;
	
	clear_nlink(inode);
	mark_inode_dirty(inode);
	mark_inode_dirty(dir);
	return 0;
}

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

static int omfs_create(struct user_namespace *mnt_userns, struct inode *dir,
		       struct dentry *dentry, umode_t mode, bool excl)
{
	return omfs_add_node(dir, dentry, mode | S_IFREG);
}

static struct dentry *omfs_lookup(struct inode *dir, struct dentry *dentry,
				  unsigned int flags)
{
	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);
	} else if (bh != ERR_PTR(-ENOENT)) {
		inode = ERR_CAST(bh);
	}
	return d_splice_alias(inode, dentry);
}

/* 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 bool omfs_fill_chain(struct inode *dir, struct dir_context *ctx,
		u64 fsblock, int hindex)
{
	/* follow chain in this bucket */
	while (fsblock != ~0) {
		struct buffer_head *bh = omfs_bread(dir->i_sb, fsblock);
		struct omfs_inode *oi;
		u64 self;
		unsigned char d_type;

		if (!bh)
			return true;

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

		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;

		if (!dir_emit(ctx, oi->i_name,
			      strnlen(oi->i_name, OMFS_NAMELEN),
			      self, d_type)) {
			brelse(bh);
			return false;
		}
		brelse(bh);
		ctx->pos++;
	}
	return true;
}

static int omfs_rename(struct user_namespace *mnt_userns, struct inode *old_dir,
		       struct dentry *old_dentry, struct inode *new_dir,
		       struct dentry *new_dentry, unsigned int flags)
{
	struct inode *new_inode = d_inode(new_dentry);
	struct inode *old_inode = d_inode(old_dentry);
	int err;

	if (flags & ~RENAME_NOREPLACE)
		return -EINVAL;

	if (new_inode) {
		/* overwriting existing file/dir */
		err = omfs_remove(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 */
	err = omfs_delete_entry(old_dentry);
	if (err)
		goto out;

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

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

static int omfs_readdir(struct file *file, struct dir_context *ctx)
{
	struct inode *dir = file_inode(file);
	struct buffer_head *bh;
	__be64 *p;
	unsigned int hchain, hindex;
	int nbuckets;

	if (ctx->pos >> 32)
		return -EINVAL;

	if (ctx->pos < 1 << 20) {
		if (!dir_emit_dots(file, ctx))
			return 0;
		ctx->pos = 1 << 20;
	}

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

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

	bh = omfs_bread(dir->i_sb, dir->i_ino);
	if (!bh)
		return -EINVAL;

	p = (__be64 *)(bh->b_data + OMFS_DIR_START) + hchain;

	for (; hchain < nbuckets; hchain++) {
		__u64 fsblock = be64_to_cpu(*p++);
		if (!omfs_fill_chain(dir, ctx, fsblock, hindex))
			break;
		hindex = 0;
		ctx->pos = (hchain+2) << 20;
	}
	brelse(bh);
	return 0;
}

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

const struct file_operations omfs_dir_operations = {
	.read = generic_read_dir,
	.iterate_shared = omfs_readdir,
	.llseek = generic_file_llseek,
};
Commit	Line	Data
59bd9ded	1	// SPDX-License-Identifier: GPL-2.0-only
a3ab7155 BC	2	/*
	3	* OMFS (as used by RIO Karma) directory operations.
	4	* Copyright (C) 2005 Bob Copeland <me@bobcopeland.com>
a3ab7155 BC	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
41c96486	96	if (S_ISDIR(inode->i_mode)) {
a3ab7155 BC	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	{
2b0143b5	113	struct inode *dir = d_inode(dentry->d_parent);
a3ab7155 BC	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
02027d42	146	dir->i_ctime = current_time(dir);
a3ab7155 BC	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	{
2b0143b5	158	struct inode *dir = d_inode(dentry->d_parent);
a3ab7155 BC	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
d932805b	238	static int omfs_remove(struct inode dir, struct dentry dentry)
a3ab7155	239	{
2b0143b5	240	struct inode *inode = d_inode(dentry);
d932805b AV	241	int ret;
d932805b AV	242
79bf7c73	243
8aaa0f54 SW	244	if (S_ISDIR(inode->i_mode) &&
	245	!omfs_dir_is_empty(inode))
	246	return -ENOTEMPTY;
a3ab7155 BC	247
	248	ret = omfs_delete_entry(dentry);
	249	if (ret)
d932805b AV	250	return ret;
	251
	252	clear_nlink(inode);
	253	mark_inode_dirty(inode);
a3ab7155	254	mark_inode_dirty(dir);
d932805b	255	return 0;
a3ab7155 BC	256	}
a3ab7155 BC	257
587228be	258	static int omfs_add_node(struct inode dir, struct dentry dentry, umode_t mode)
a3ab7155 BC	259	{
	260	int err;
	261	struct inode *inode = omfs_new_inode(dir, mode);
	262
	263	if (IS_ERR(inode))
	264	return PTR_ERR(inode);
	265
	266	err = omfs_make_empty(inode, dir->i_sb);
	267	if (err)
	268	goto out_free_inode;
	269
	270	err = omfs_add_link(dentry, inode);
	271	if (err)
	272	goto out_free_inode;
	273
	274	d_instantiate(dentry, inode);
	275	return 0;
	276
	277	out_free_inode:
	278	iput(inode);
	279	return err;
	280	}
	281
549c7297 CB	282	static int omfs_mkdir(struct user_namespace mnt_userns, struct inode dir,
549c7297 CB	283	struct dentry *dentry, umode_t mode)
a3ab7155 BC	284	{
	285	return omfs_add_node(dir, dentry, mode \| S_IFDIR);
	286	}
	287
549c7297 CB	288	static int omfs_create(struct user_namespace mnt_userns, struct inode dir,
549c7297 CB	289	struct dentry *dentry, umode_t mode, bool excl)
a3ab7155 BC	290	{
	291	return omfs_add_node(dir, dentry, mode \| S_IFREG);
	292	}
	293
	294	static struct dentry omfs_lookup(struct inode dir, struct dentry *dentry,
00cd8dd3	295	unsigned int flags)
a3ab7155 BC	296	{
	297	struct buffer_head *bh;
	298	struct inode *inode = NULL;
	299
	300	if (dentry->d_name.len > OMFS_NAMELEN)
	301	return ERR_PTR(-ENAMETOOLONG);
	302
	303	bh = omfs_find_entry(dir, dentry->d_name.name, dentry->d_name.len);
	304	if (!IS_ERR(bh)) {
	305	struct omfs_inode oi = (struct omfs_inode )bh->b_data;
	306	ino_t ino = be64_to_cpu(oi->i_head.h_self);
	307	brelse(bh);
	308	inode = omfs_iget(dir->i_sb, ino);
18fbbfc2 AV	309	} else if (bh != ERR_PTR(-ENOENT)) {
18fbbfc2 AV	310	inode = ERR_CAST(bh);
a3ab7155	311	}
18fbbfc2	312	return d_splice_alias(inode, dentry);
a3ab7155 BC	313	}
	314
	315	/* sanity check block's self pointer */
	316	int omfs_is_bad(struct omfs_sb_info sbi, struct omfs_header header,
	317	u64 fsblock)
	318	{
	319	int is_bad;
	320	u64 ino = be64_to_cpu(header->h_self);
	321	is_bad = ((ino != fsblock) \|\| (ino < sbi->s_root_ino) \|\|
	322	(ino > sbi->s_num_blocks));
	323
	324	if (is_bad)
	325	printk(KERN_WARNING "omfs: bad hash chain detected\n");
	326
	327	return is_bad;
	328	}
	329
9fd4d059	330	static bool omfs_fill_chain(struct inode dir, struct dir_context ctx,
a3ab7155 BC	331	u64 fsblock, int hindex)
a3ab7155 BC	332	{
a3ab7155 BC	333	/* follow chain in this bucket */
a3ab7155 BC	334	while (fsblock != ~0) {
9fd4d059 AV	335	struct buffer_head *bh = omfs_bread(dir->i_sb, fsblock);
	336	struct omfs_inode *oi;
	337	u64 self;
	338	unsigned char d_type;
	339
a3ab7155	340	if (!bh)
9fd4d059	341	return true;
a3ab7155 BC	342
	343	oi = (struct omfs_inode *) bh->b_data;
	344	if (omfs_is_bad(OMFS_SB(dir->i_sb), &oi->i_head, fsblock)) {
	345	brelse(bh);
9fd4d059	346	return true;
a3ab7155 BC	347	}
	348
	349	self = fsblock;
	350	fsblock = be64_to_cpu(oi->i_sibling);
	351
	352	/* skip visited nodes */
	353	if (hindex) {
	354	hindex--;
	355	brelse(bh);
	356	continue;
	357	}
	358
	359	d_type = (oi->i_type == OMFS_DIR) ? DT_DIR : DT_REG;
	360
9fd4d059 AV	361	if (!dir_emit(ctx, oi->i_name,
	362	strnlen(oi->i_name, OMFS_NAMELEN),
	363	self, d_type)) {
	364	brelse(bh);
	365	return false;
	366	}
a3ab7155	367	brelse(bh);
9fd4d059	368	ctx->pos++;
a3ab7155	369	}
9fd4d059	370	return true;
a3ab7155 BC	371	}
a3ab7155 BC	372
549c7297 CB	373	static int omfs_rename(struct user_namespace mnt_userns, struct inode old_dir,
	374	struct dentry old_dentry, struct inode new_dir,
	375	struct dentry *new_dentry, unsigned int flags)
a3ab7155	376	{
2b0143b5 DH	377	struct inode *new_inode = d_inode(new_dentry);
2b0143b5 DH	378	struct inode *old_inode = d_inode(old_dentry);
a3ab7155 BC	379	int err;
a3ab7155 BC	380
f03b8ad8 MS	381	if (flags & ~RENAME_NOREPLACE)
	382	return -EINVAL;
	383
a3ab7155 BC	384	if (new_inode) {
a3ab7155 BC	385	/* overwriting existing file/dir */
d932805b	386	err = omfs_remove(new_dir, new_dentry);
a3ab7155 BC	387	if (err)
	388	goto out;
	389	}
	390
	391	/* since omfs locates files by name, we need to unlink _before_
	392	* adding the new link or we won't find the old one */
cdb26496 AV	393	err = omfs_delete_entry(old_dentry);
cdb26496 AV	394	if (err)
a3ab7155	395	goto out;
a3ab7155	396
cdb26496	397	mark_inode_dirty(old_dir);
a3ab7155 BC	398	err = omfs_add_link(new_dentry, old_inode);
	399	if (err)
	400	goto out;
	401
02027d42	402	old_inode->i_ctime = current_time(old_inode);
013e4f4a	403	mark_inode_dirty(old_inode);
a3ab7155 BC	404	out:
	405	return err;
	406	}
	407
9fd4d059	408	static int omfs_readdir(struct file file, struct dir_context ctx)
a3ab7155	409	{
9fd4d059	410	struct inode *dir = file_inode(file);
a3ab7155	411	struct buffer_head *bh;
9fd4d059	412	__be64 *p;
a3ab7155 BC	413	unsigned int hchain, hindex;
a3ab7155 BC	414	int nbuckets;
9fd4d059 AV	415
	416	if (ctx->pos >> 32)
	417	return -EINVAL;
	418
	419	if (ctx->pos < 1 << 20) {
	420	if (!dir_emit_dots(file, ctx))
	421	return 0;
	422	ctx->pos = 1 << 20;
a3ab7155 BC	423	}
	424
	425	nbuckets = (dir->i_size - OMFS_DIR_START) / 8;
	426
	427	/* high 12 bits store bucket + 1 and low 20 bits store hash index */
9fd4d059 AV	428	hchain = (ctx->pos >> 20) - 1;
9fd4d059 AV	429	hindex = ctx->pos & 0xfffff;
a3ab7155	430
f068272c	431	bh = omfs_bread(dir->i_sb, dir->i_ino);
a3ab7155	432	if (!bh)
9fd4d059	433	return -EINVAL;
a3ab7155	434
9fd4d059	435	p = (__be64 *)(bh->b_data + OMFS_DIR_START) + hchain;
a3ab7155	436
9fd4d059 AV	437	for (; hchain < nbuckets; hchain++) {
	438	__u64 fsblock = be64_to_cpu(*p++);
	439	if (!omfs_fill_chain(dir, ctx, fsblock, hindex))
a3ab7155	440	break;
9fd4d059 AV	441	hindex = 0;
9fd4d059 AV	442	ctx->pos = (hchain+2) << 20;
a3ab7155 BC	443	}
a3ab7155 BC	444	brelse(bh);
9fd4d059	445	return 0;
a3ab7155 BC	446	}
a3ab7155 BC	447
6e1d5dcc	448	const struct inode_operations omfs_dir_inops = {
a3ab7155 BC	449	.lookup = omfs_lookup,
	450	.mkdir = omfs_mkdir,
	451	.rename = omfs_rename,
	452	.create = omfs_create,
d932805b AV	453	.unlink = omfs_remove,
d932805b AV	454	.rmdir = omfs_remove,
a3ab7155 BC	455	};
a3ab7155 BC	456
828c0950	457	const struct file_operations omfs_dir_operations = {
a3ab7155	458	.read = generic_read_dir,
c51da20c	459	.iterate_shared = omfs_readdir,
3222a3e5	460	.llseek = generic_file_llseek,
a3ab7155	461	};