[linux.git] / fs / nilfs2 / dir.c

/*
 * dir.c - NILFS directory entry operations
 *
 * Copyright (C) 2005-2008 Nippon Telegraph and Telephone Corporation.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * Modified for NILFS by Amagai Yoshiji.
 */
/*
 *  linux/fs/ext2/dir.c
 *
 * Copyright (C) 1992, 1993, 1994, 1995
 * Remy Card ([email protected])
 * Laboratoire MASI - Institut Blaise Pascal
 * Universite Pierre et Marie Curie (Paris VI)
 *
 *  from
 *
 *  linux/fs/minix/dir.c
 *
 *  Copyright (C) 1991, 1992  Linus Torvalds
 *
 *  ext2 directory handling functions
 *
 *  Big-endian to little-endian byte-swapping/bitmaps by
 *        David S. Miller ([email protected]), 1995
 *
 * All code that works with directory layout had been switched to pagecache
 * and moved here. AV
 */

#include <linux/pagemap.h>
#include "nilfs.h"
#include "page.h"

static inline unsigned int nilfs_rec_len_from_disk(__le16 dlen)
{
	unsigned int len = le16_to_cpu(dlen);

#if (PAGE_SIZE >= 65536)
	if (len == NILFS_MAX_REC_LEN)
		return 1 << 16;
#endif
	return len;
}

static inline __le16 nilfs_rec_len_to_disk(unsigned int len)
{
#if (PAGE_SIZE >= 65536)
	if (len == (1 << 16))
		return cpu_to_le16(NILFS_MAX_REC_LEN);

	BUG_ON(len > (1 << 16));
#endif
	return cpu_to_le16(len);
}

/*
 * nilfs uses block-sized chunks. Arguably, sector-sized ones would be
 * more robust, but we have what we have
 */
static inline unsigned int nilfs_chunk_size(struct inode *inode)
{
	return inode->i_sb->s_blocksize;
}

static inline void nilfs_put_page(struct page *page)
{
	kunmap(page);
	put_page(page);
}

/*
 * Return the offset into page `page_nr' of the last valid
 * byte in that page, plus one.
 */
static unsigned int nilfs_last_byte(struct inode *inode, unsigned long page_nr)
{
	unsigned int last_byte = inode->i_size;

	last_byte -= page_nr << PAGE_SHIFT;
	if (last_byte > PAGE_SIZE)
		last_byte = PAGE_SIZE;
	return last_byte;
}

static int nilfs_prepare_chunk(struct page *page, unsigned int from,
			       unsigned int to)
{
	loff_t pos = page_offset(page) + from;

	return __block_write_begin(page, pos, to - from, nilfs_get_block);
}

static void nilfs_commit_chunk(struct page *page,
			       struct address_space *mapping,
			       unsigned int from, unsigned int to)
{
	struct inode *dir = mapping->host;
	loff_t pos = page_offset(page) + from;
	unsigned int len = to - from;
	unsigned int nr_dirty, copied;
	int err;

	nr_dirty = nilfs_page_count_clean_buffers(page, from, to);
	copied = block_write_end(NULL, mapping, pos, len, len, page, NULL);
	if (pos + copied > dir->i_size)
		i_size_write(dir, pos + copied);
	if (IS_DIRSYNC(dir))
		nilfs_set_transaction_flag(NILFS_TI_SYNC);
	err = nilfs_set_file_dirty(dir, nr_dirty);
	WARN_ON(err); /* do not happen */
	unlock_page(page);
}

static bool nilfs_check_page(struct page *page)
{
	struct inode *dir = page->mapping->host;
	struct super_block *sb = dir->i_sb;
	unsigned int chunk_size = nilfs_chunk_size(dir);
	char *kaddr = page_address(page);
	unsigned int offs, rec_len;
	unsigned int limit = PAGE_SIZE;
	struct nilfs_dir_entry *p;
	char *error;

	if ((dir->i_size >> PAGE_SHIFT) == page->index) {
		limit = dir->i_size & ~PAGE_MASK;
		if (limit & (chunk_size - 1))
			goto Ebadsize;
		if (!limit)
			goto out;
	}
	for (offs = 0; offs <= limit - NILFS_DIR_REC_LEN(1); offs += rec_len) {
		p = (struct nilfs_dir_entry *)(kaddr + offs);
		rec_len = nilfs_rec_len_from_disk(p->rec_len);

		if (rec_len < NILFS_DIR_REC_LEN(1))
			goto Eshort;
		if (rec_len & 3)
			goto Ealign;
		if (rec_len < NILFS_DIR_REC_LEN(p->name_len))
			goto Enamelen;
		if (((offs + rec_len - 1) ^ offs) & ~(chunk_size-1))
			goto Espan;
	}
	if (offs != limit)
		goto Eend;
out:
	SetPageChecked(page);
	return true;

	/* Too bad, we had an error */

Ebadsize:
	nilfs_error(sb,
		    "size of directory #%lu is not a multiple of chunk size",
		    dir->i_ino);
	goto fail;
Eshort:
	error = "rec_len is smaller than minimal";
	goto bad_entry;
Ealign:
	error = "unaligned directory entry";
	goto bad_entry;
Enamelen:
	error = "rec_len is too small for name_len";
	goto bad_entry;
Espan:
	error = "directory entry across blocks";
bad_entry:
	nilfs_error(sb,
		    "bad entry in directory #%lu: %s - offset=%lu, inode=%lu, rec_len=%d, name_len=%d",
		    dir->i_ino, error, (page->index << PAGE_SHIFT) + offs,
		    (unsigned long)le64_to_cpu(p->inode),
		    rec_len, p->name_len);
	goto fail;
Eend:
	p = (struct nilfs_dir_entry *)(kaddr + offs);
	nilfs_error(sb,
		    "entry in directory #%lu spans the page boundary offset=%lu, inode=%lu",
		    dir->i_ino, (page->index << PAGE_SHIFT) + offs,
		    (unsigned long)le64_to_cpu(p->inode));
fail:
	SetPageError(page);
	return false;
}

static struct page *nilfs_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 (unlikely(!PageChecked(page))) {
			if (PageError(page) || !nilfs_check_page(page))
				goto fail;
		}
	}
	return page;

fail:
	nilfs_put_page(page);
	return ERR_PTR(-EIO);
}

/*
 * NOTE! unlike strncmp, nilfs_match returns 1 for success, 0 for failure.
 *
 * len <= NILFS_NAME_LEN and de != NULL are guaranteed by caller.
 */
static int
nilfs_match(int len, const unsigned char *name, struct nilfs_dir_entry *de)
{
	if (len != de->name_len)
		return 0;
	if (!de->inode)
		return 0;
	return !memcmp(name, de->name, len);
}

/*
 * p is at least 6 bytes before the end of page
 */
static struct nilfs_dir_entry *nilfs_next_entry(struct nilfs_dir_entry *p)
{
	return (struct nilfs_dir_entry *)((char *)p +
					  nilfs_rec_len_from_disk(p->rec_len));
}

static unsigned char
nilfs_filetype_table[NILFS_FT_MAX] = {
	[NILFS_FT_UNKNOWN]	= DT_UNKNOWN,
	[NILFS_FT_REG_FILE]	= DT_REG,
	[NILFS_FT_DIR]		= DT_DIR,
	[NILFS_FT_CHRDEV]	= DT_CHR,
	[NILFS_FT_BLKDEV]	= DT_BLK,
	[NILFS_FT_FIFO]		= DT_FIFO,
	[NILFS_FT_SOCK]		= DT_SOCK,
	[NILFS_FT_SYMLINK]	= DT_LNK,
};

#define S_SHIFT 12
static unsigned char
nilfs_type_by_mode[S_IFMT >> S_SHIFT] = {
	[S_IFREG >> S_SHIFT]	= NILFS_FT_REG_FILE,
	[S_IFDIR >> S_SHIFT]	= NILFS_FT_DIR,
	[S_IFCHR >> S_SHIFT]	= NILFS_FT_CHRDEV,
	[S_IFBLK >> S_SHIFT]	= NILFS_FT_BLKDEV,
	[S_IFIFO >> S_SHIFT]	= NILFS_FT_FIFO,
	[S_IFSOCK >> S_SHIFT]	= NILFS_FT_SOCK,
	[S_IFLNK >> S_SHIFT]	= NILFS_FT_SYMLINK,
};

static void nilfs_set_de_type(struct nilfs_dir_entry *de, struct inode *inode)
{
	umode_t mode = inode->i_mode;

	de->file_type = nilfs_type_by_mode[(mode & S_IFMT)>>S_SHIFT];
}

static int nilfs_readdir(struct file *file, struct dir_context *ctx)
{
	loff_t pos = ctx->pos;
	struct inode *inode = file_inode(file);
	struct super_block *sb = inode->i_sb;
	unsigned int offset = pos & ~PAGE_MASK;
	unsigned long n = pos >> PAGE_SHIFT;
	unsigned long npages = dir_pages(inode);

	if (pos > inode->i_size - NILFS_DIR_REC_LEN(1))
		return 0;

	for ( ; n < npages; n++, offset = 0) {
		char *kaddr, *limit;
		struct nilfs_dir_entry *de;
		struct page *page = nilfs_get_page(inode, n);

		if (IS_ERR(page)) {
			nilfs_error(sb, "bad page in #%lu", inode->i_ino);
			ctx->pos += PAGE_SIZE - offset;
			return -EIO;
		}
		kaddr = page_address(page);
		de = (struct nilfs_dir_entry *)(kaddr + offset);
		limit = kaddr + nilfs_last_byte(inode, n) -
			NILFS_DIR_REC_LEN(1);
		for ( ; (char *)de <= limit; de = nilfs_next_entry(de)) {
			if (de->rec_len == 0) {
				nilfs_error(sb, "zero-length directory entry");
				nilfs_put_page(page);
				return -EIO;
			}
			if (de->inode) {
				unsigned char t;

				if (de->file_type < NILFS_FT_MAX)
					t = nilfs_filetype_table[de->file_type];
				else
					t = DT_UNKNOWN;

				if (!dir_emit(ctx, de->name, de->name_len,
						le64_to_cpu(de->inode), t)) {
					nilfs_put_page(page);
					return 0;
				}
			}
			ctx->pos += nilfs_rec_len_from_disk(de->rec_len);
		}
		nilfs_put_page(page);
	}
	return 0;
}

/*
 *	nilfs_find_entry()
 *
 * finds an entry in the specified directory with the wanted name. It
 * returns the page in which the entry was found, and the entry itself
 * (as a parameter - res_dir). Page is returned mapped and unlocked.
 * Entry is guaranteed to be valid.
 */
struct nilfs_dir_entry *
nilfs_find_entry(struct inode *dir, const struct qstr *qstr,
		 struct page **res_page)
{
	const unsigned char *name = qstr->name;
	int namelen = qstr->len;
	unsigned int reclen = NILFS_DIR_REC_LEN(namelen);
	unsigned long start, n;
	unsigned long npages = dir_pages(dir);
	struct page *page = NULL;
	struct nilfs_inode_info *ei = NILFS_I(dir);
	struct nilfs_dir_entry *de;

	if (npages == 0)
		goto out;

	/* OFFSET_CACHE */
	*res_page = NULL;

	start = ei->i_dir_start_lookup;
	if (start >= npages)
		start = 0;
	n = start;
	do {
		char *kaddr;

		page = nilfs_get_page(dir, n);
		if (!IS_ERR(page)) {
			kaddr = page_address(page);
			de = (struct nilfs_dir_entry *)kaddr;
			kaddr += nilfs_last_byte(dir, n) - reclen;
			while ((char *) de <= kaddr) {
				if (de->rec_len == 0) {
					nilfs_error(dir->i_sb,
						"zero-length directory entry");
					nilfs_put_page(page);
					goto out;
				}
				if (nilfs_match(namelen, name, de))
					goto found;
				de = nilfs_next_entry(de);
			}
			nilfs_put_page(page);
		}
		if (++n >= npages)
			n = 0;
		/* next page is past the blocks we've got */
		if (unlikely(n > (dir->i_blocks >> (PAGE_SHIFT - 9)))) {
			nilfs_error(dir->i_sb,
			       "dir %lu size %lld exceeds block count %llu",
			       dir->i_ino, dir->i_size,
			       (unsigned long long)dir->i_blocks);
			goto out;
		}
	} while (n != start);
out:
	return NULL;

found:
	*res_page = page;
	ei->i_dir_start_lookup = n;
	return de;
}

struct nilfs_dir_entry *nilfs_dotdot(struct inode *dir, struct page **p)
{
	struct page *page = nilfs_get_page(dir, 0);
	struct nilfs_dir_entry *de = NULL;

	if (!IS_ERR(page)) {
		de = nilfs_next_entry(
			(struct nilfs_dir_entry *)page_address(page));
		*p = page;
	}
	return de;
}

ino_t nilfs_inode_by_name(struct inode *dir, const struct qstr *qstr)
{
	ino_t res = 0;
	struct nilfs_dir_entry *de;
	struct page *page;

	de = nilfs_find_entry(dir, qstr, &page);
	if (de) {
		res = le64_to_cpu(de->inode);
		kunmap(page);
		put_page(page);
	}
	return res;
}

/* Releases the page */
void nilfs_set_link(struct inode *dir, struct nilfs_dir_entry *de,
		    struct page *page, struct inode *inode)
{
	unsigned int from = (char *)de - (char *)page_address(page);
	unsigned int to = from + nilfs_rec_len_from_disk(de->rec_len);
	struct address_space *mapping = page->mapping;
	int err;

	lock_page(page);
	err = nilfs_prepare_chunk(page, from, to);
	BUG_ON(err);
	de->inode = cpu_to_le64(inode->i_ino);
	nilfs_set_de_type(de, inode);
	nilfs_commit_chunk(page, mapping, from, to);
	nilfs_put_page(page);
	dir->i_mtime = dir->i_ctime = CURRENT_TIME;
}

/*
 *	Parent is locked.
 */
int nilfs_add_link(struct dentry *dentry, struct inode *inode)
{
	struct inode *dir = d_inode(dentry->d_parent);
	const unsigned char *name = dentry->d_name.name;
	int namelen = dentry->d_name.len;
	unsigned int chunk_size = nilfs_chunk_size(dir);
	unsigned int reclen = NILFS_DIR_REC_LEN(namelen);
	unsigned short rec_len, name_len;
	struct page *page = NULL;
	struct nilfs_dir_entry *de;
	unsigned long npages = dir_pages(dir);
	unsigned long n;
	char *kaddr;
	unsigned int from, to;
	int err;

	/*
	 * 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 *dir_end;

		page = nilfs_get_page(dir, n);
		err = PTR_ERR(page);
		if (IS_ERR(page))
			goto out;
		lock_page(page);
		kaddr = page_address(page);
		dir_end = kaddr + nilfs_last_byte(dir, n);
		de = (struct nilfs_dir_entry *)kaddr;
		kaddr += PAGE_SIZE - reclen;
		while ((char *)de <= kaddr) {
			if ((char *)de == dir_end) {
				/* We hit i_size */
				name_len = 0;
				rec_len = chunk_size;
				de->rec_len = nilfs_rec_len_to_disk(chunk_size);
				de->inode = 0;
				goto got_it;
			}
			if (de->rec_len == 0) {
				nilfs_error(dir->i_sb,
					    "zero-length directory entry");
				err = -EIO;
				goto out_unlock;
			}
			err = -EEXIST;
			if (nilfs_match(namelen, name, de))
				goto out_unlock;
			name_len = NILFS_DIR_REC_LEN(de->name_len);
			rec_len = nilfs_rec_len_from_disk(de->rec_len);
			if (!de->inode && rec_len >= reclen)
				goto got_it;
			if (rec_len >= name_len + reclen)
				goto got_it;
			de = (struct nilfs_dir_entry *)((char *)de + rec_len);
		}
		unlock_page(page);
		nilfs_put_page(page);
	}
	BUG();
	return -EINVAL;

got_it:
	from = (char *)de - (char *)page_address(page);
	to = from + rec_len;
	err = nilfs_prepare_chunk(page, from, to);
	if (err)
		goto out_unlock;
	if (de->inode) {
		struct nilfs_dir_entry *de1;

		de1 = (struct nilfs_dir_entry *)((char *)de + name_len);
		de1->rec_len = nilfs_rec_len_to_disk(rec_len - name_len);
		de->rec_len = nilfs_rec_len_to_disk(name_len);
		de = de1;
	}
	de->name_len = namelen;
	memcpy(de->name, name, namelen);
	de->inode = cpu_to_le64(inode->i_ino);
	nilfs_set_de_type(de, inode);
	nilfs_commit_chunk(page, page->mapping, from, to);
	dir->i_mtime = dir->i_ctime = CURRENT_TIME;
	nilfs_mark_inode_dirty(dir);
	/* OFFSET_CACHE */
out_put:
	nilfs_put_page(page);
out:
	return err;
out_unlock:
	unlock_page(page);
	goto out_put;
}

/*
 * nilfs_delete_entry deletes a directory entry by merging it with the
 * previous entry. Page is up-to-date. Releases the page.
 */
int nilfs_delete_entry(struct nilfs_dir_entry *dir, struct page *page)
{
	struct address_space *mapping = page->mapping;
	struct inode *inode = mapping->host;
	char *kaddr = page_address(page);
	unsigned int from, to;
	struct nilfs_dir_entry *de, *pde = NULL;
	int err;

	from = ((char *)dir - kaddr) & ~(nilfs_chunk_size(inode) - 1);
	to = ((char *)dir - kaddr) + nilfs_rec_len_from_disk(dir->rec_len);
	de = (struct nilfs_dir_entry *)(kaddr + from);

	while ((char *)de < (char *)dir) {
		if (de->rec_len == 0) {
			nilfs_error(inode->i_sb,
				    "zero-length directory entry");
			err = -EIO;
			goto out;
		}
		pde = de;
		de = nilfs_next_entry(de);
	}
	if (pde)
		from = (char *)pde - (char *)page_address(page);
	lock_page(page);
	err = nilfs_prepare_chunk(page, from, to);
	BUG_ON(err);
	if (pde)
		pde->rec_len = nilfs_rec_len_to_disk(to - from);
	dir->inode = 0;
	nilfs_commit_chunk(page, mapping, from, to);
	inode->i_ctime = inode->i_mtime = CURRENT_TIME;
out:
	nilfs_put_page(page);
	return err;
}

/*
 * Set the first fragment of directory.
 */
int nilfs_make_empty(struct inode *inode, struct inode *parent)
{
	struct address_space *mapping = inode->i_mapping;
	struct page *page = grab_cache_page(mapping, 0);
	unsigned int chunk_size = nilfs_chunk_size(inode);
	struct nilfs_dir_entry *de;
	int err;
	void *kaddr;

	if (!page)
		return -ENOMEM;

	err = nilfs_prepare_chunk(page, 0, chunk_size);
	if (unlikely(err)) {
		unlock_page(page);
		goto fail;
	}
	kaddr = kmap_atomic(page);
	memset(kaddr, 0, chunk_size);
	de = (struct nilfs_dir_entry *)kaddr;
	de->name_len = 1;
	de->rec_len = nilfs_rec_len_to_disk(NILFS_DIR_REC_LEN(1));
	memcpy(de->name, ".\0\0", 4);
	de->inode = cpu_to_le64(inode->i_ino);
	nilfs_set_de_type(de, inode);

	de = (struct nilfs_dir_entry *)(kaddr + NILFS_DIR_REC_LEN(1));
	de->name_len = 2;
	de->rec_len = nilfs_rec_len_to_disk(chunk_size - NILFS_DIR_REC_LEN(1));
	de->inode = cpu_to_le64(parent->i_ino);
	memcpy(de->name, "..\0", 4);
	nilfs_set_de_type(de, inode);
	kunmap_atomic(kaddr);
	nilfs_commit_chunk(page, mapping, 0, chunk_size);
fail:
	put_page(page);
	return err;
}

/*
 * routine to check that the specified directory is empty (for rmdir)
 */
int nilfs_empty_dir(struct inode *inode)
{
	struct page *page = NULL;
	unsigned long i, npages = dir_pages(inode);

	for (i = 0; i < npages; i++) {
		char *kaddr;
		struct nilfs_dir_entry *de;

		page = nilfs_get_page(inode, i);
		if (IS_ERR(page))
			continue;

		kaddr = page_address(page);
		de = (struct nilfs_dir_entry *)kaddr;
		kaddr += nilfs_last_byte(inode, i) - NILFS_DIR_REC_LEN(1);

		while ((char *)de <= kaddr) {
			if (de->rec_len == 0) {
				nilfs_error(inode->i_sb,
					    "zero-length directory entry (kaddr=%p, de=%p)",
					    kaddr, de);
				goto not_empty;
			}
			if (de->inode != 0) {
				/* check for . and .. */
				if (de->name[0] != '.')
					goto not_empty;
				if (de->name_len > 2)
					goto not_empty;
				if (de->name_len < 2) {
					if (de->inode !=
					    cpu_to_le64(inode->i_ino))
						goto not_empty;
				} else if (de->name[1] != '.')
					goto not_empty;
			}
			de = nilfs_next_entry(de);
		}
		nilfs_put_page(page);
	}
	return 1;

not_empty:
	nilfs_put_page(page);
	return 0;
}

const struct file_operations nilfs_dir_operations = {
	.llseek		= generic_file_llseek,
	.read		= generic_read_dir,
	.iterate_shared	= nilfs_readdir,
	.unlocked_ioctl	= nilfs_ioctl,
#ifdef CONFIG_COMPAT
	.compat_ioctl	= nilfs_compat_ioctl,
#endif	/* CONFIG_COMPAT */
	.fsync		= nilfs_sync_file,

};
Commit	Line	Data
2ba466d7 YA	1	/*
	2	* dir.c - NILFS directory entry operations
	3	*
	4	* Copyright (C) 2005-2008 Nippon Telegraph and Telephone Corporation.
	5	*
	6	* This program is free software; you can redistribute it and/or modify
	7	* it under the terms of the GNU General Public License as published by
	8	* the Free Software Foundation; either version 2 of the License, or
	9	* (at your option) any later version.
	10	*
	11	* This program is distributed in the hope that it will be useful,
	12	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	13	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	14	* GNU General Public License for more details.
	15	*
4b420ab4	16	* Modified for NILFS by Amagai Yoshiji.
2ba466d7 YA	17	*/
	18	/*
	19	* linux/fs/ext2/dir.c
	20	*
	21	* Copyright (C) 1992, 1993, 1994, 1995
	22	* Remy Card ([email protected])
	23	* Laboratoire MASI - Institut Blaise Pascal
	24	* Universite Pierre et Marie Curie (Paris VI)
	25	*
	26	* from
	27	*
	28	* linux/fs/minix/dir.c
	29	*
	30	* Copyright (C) 1991, 1992 Linus Torvalds
	31	*
	32	* ext2 directory handling functions
	33	*
	34	* Big-endian to little-endian byte-swapping/bitmaps by
	35	* David S. Miller ([email protected]), 1995
	36	*
	37	* All code that works with directory layout had been switched to pagecache
	38	* and moved here. AV
	39	*/
	40
	41	#include <linux/pagemap.h>
2ba466d7 YA	42	#include "nilfs.h"
	43	#include "page.h"
	44
e63e88bc RK	45	static inline unsigned int nilfs_rec_len_from_disk(__le16 dlen)
	46	{
	47	unsigned int len = le16_to_cpu(dlen);
	48
	49	#if (PAGE_SIZE >= 65536)
	50	if (len == NILFS_MAX_REC_LEN)
	51	return 1 << 16;
	52	#endif
	53	return len;
	54	}
	55
	56	static inline __le16 nilfs_rec_len_to_disk(unsigned int len)
	57	{
	58	#if (PAGE_SIZE >= 65536)
	59	if (len == (1 << 16))
	60	return cpu_to_le16(NILFS_MAX_REC_LEN);
	61
	62	BUG_ON(len > (1 << 16));
	63	#endif
	64	return cpu_to_le16(len);
	65	}
	66
2ba466d7 YA	67	/*
	68	* nilfs uses block-sized chunks. Arguably, sector-sized ones would be
	69	* more robust, but we have what we have
	70	*/
0c6c44cb	71	static inline unsigned int nilfs_chunk_size(struct inode *inode)
2ba466d7 YA	72	{
	73	return inode->i_sb->s_blocksize;
	74	}
	75
	76	static inline void nilfs_put_page(struct page *page)
	77	{
	78	kunmap(page);
09cbfeaf	79	put_page(page);
2ba466d7 YA	80	}
2ba466d7 YA	81
2ba466d7 YA	82	/*
	83	* Return the offset into page `page_nr' of the last valid
	84	* byte in that page, plus one.
	85	*/
0c6c44cb	86	static unsigned int nilfs_last_byte(struct inode *inode, unsigned long page_nr)
2ba466d7	87	{
0c6c44cb	88	unsigned int last_byte = inode->i_size;
2ba466d7	89
09cbfeaf KS	90	last_byte -= page_nr << PAGE_SHIFT;
	91	if (last_byte > PAGE_SIZE)
	92	last_byte = PAGE_SIZE;
2ba466d7 YA	93	return last_byte;
	94	}
	95
0c6c44cb RK	96	static int nilfs_prepare_chunk(struct page *page, unsigned int from,
0c6c44cb RK	97	unsigned int to)
2ba466d7 YA	98	{
2ba466d7 YA	99	loff_t pos = page_offset(page) + from;
4ad364ca	100
6e1db88d	101	return __block_write_begin(page, pos, to - from, nilfs_get_block);
2ba466d7 YA	102	}
2ba466d7 YA	103
2093abf9 JS	104	static void nilfs_commit_chunk(struct page *page,
2093abf9 JS	105	struct address_space *mapping,
0c6c44cb	106	unsigned int from, unsigned int to)
2ba466d7 YA	107	{
2ba466d7 YA	108	struct inode *dir = mapping->host;
2ba466d7	109	loff_t pos = page_offset(page) + from;
0c6c44cb RK	110	unsigned int len = to - from;
0c6c44cb RK	111	unsigned int nr_dirty, copied;
2ba466d7 YA	112	int err;
	113
	114	nr_dirty = nilfs_page_count_clean_buffers(page, from, to);
	115	copied = block_write_end(NULL, mapping, pos, len, len, page, NULL);
58d55471	116	if (pos + copied > dir->i_size)
2ba466d7	117	i_size_write(dir, pos + copied);
2ba466d7 YA	118	if (IS_DIRSYNC(dir))
2ba466d7 YA	119	nilfs_set_transaction_flag(NILFS_TI_SYNC);
bcbc8c64	120	err = nilfs_set_file_dirty(dir, nr_dirty);
2093abf9	121	WARN_ON(err); /* do not happen */
2ba466d7	122	unlock_page(page);
2ba466d7 YA	123	}
2ba466d7 YA	124
be5b82db	125	static bool nilfs_check_page(struct page *page)
2ba466d7 YA	126	{
	127	struct inode *dir = page->mapping->host;
	128	struct super_block *sb = dir->i_sb;
0c6c44cb	129	unsigned int chunk_size = nilfs_chunk_size(dir);
2ba466d7	130	char *kaddr = page_address(page);
0c6c44cb RK	131	unsigned int offs, rec_len;
0c6c44cb RK	132	unsigned int limit = PAGE_SIZE;
2ba466d7 YA	133	struct nilfs_dir_entry *p;
	134	char *error;
	135
09cbfeaf KS	136	if ((dir->i_size >> PAGE_SHIFT) == page->index) {
09cbfeaf KS	137	limit = dir->i_size & ~PAGE_MASK;
2ba466d7 YA	138	if (limit & (chunk_size - 1))
	139	goto Ebadsize;
	140	if (!limit)
	141	goto out;
	142	}
	143	for (offs = 0; offs <= limit - NILFS_DIR_REC_LEN(1); offs += rec_len) {
	144	p = (struct nilfs_dir_entry *)(kaddr + offs);
6cda9fa2	145	rec_len = nilfs_rec_len_from_disk(p->rec_len);
2ba466d7 YA	146
	147	if (rec_len < NILFS_DIR_REC_LEN(1))
	148	goto Eshort;
	149	if (rec_len & 3)
	150	goto Ealign;
	151	if (rec_len < NILFS_DIR_REC_LEN(p->name_len))
	152	goto Enamelen;
	153	if (((offs + rec_len - 1) ^ offs) & ~(chunk_size-1))
	154	goto Espan;
	155	}
	156	if (offs != limit)
	157	goto Eend;
	158	out:
	159	SetPageChecked(page);
be5b82db	160	return true;
2ba466d7 YA	161
	162	/* Too bad, we had an error */
	163
	164	Ebadsize:
cae3d4ca	165	nilfs_error(sb,
2ba466d7	166	"size of directory #%lu is not a multiple of chunk size",
cae3d4ca	167	dir->i_ino);
2ba466d7 YA	168	goto fail;
	169	Eshort:
	170	error = "rec_len is smaller than minimal";
	171	goto bad_entry;
	172	Ealign:
	173	error = "unaligned directory entry";
	174	goto bad_entry;
	175	Enamelen:
	176	error = "rec_len is too small for name_len";
	177	goto bad_entry;
	178	Espan:
	179	error = "directory entry across blocks";
	180	bad_entry:
cae3d4ca RK	181	nilfs_error(sb,
	182	"bad entry in directory #%lu: %s - offset=%lu, inode=%lu, rec_len=%d, name_len=%d",
	183	dir->i_ino, error, (page->index << PAGE_SHIFT) + offs,
	184	(unsigned long)le64_to_cpu(p->inode),
2ba466d7 YA	185	rec_len, p->name_len);
	186	goto fail;
	187	Eend:
	188	p = (struct nilfs_dir_entry *)(kaddr + offs);
cae3d4ca RK	189	nilfs_error(sb,
	190	"entry in directory #%lu spans the page boundary offset=%lu, inode=%lu",
	191	dir->i_ino, (page->index << PAGE_SHIFT) + offs,
	192	(unsigned long)le64_to_cpu(p->inode));
2ba466d7	193	fail:
2ba466d7	194	SetPageError(page);
be5b82db	195	return false;
2ba466d7 YA	196	}
	197
	198	static struct page nilfs_get_page(struct inode dir, unsigned long n)
	199	{
	200	struct address_space *mapping = dir->i_mapping;
c28e69d9 RK	201	struct page *page = read_mapping_page(mapping, n, NULL);
c28e69d9 RK	202
2ba466d7	203	if (!IS_ERR(page)) {
2ba466d7	204	kmap(page);
be5b82db AV	205	if (unlikely(!PageChecked(page))) {
	206	if (PageError(page) \|\| !nilfs_check_page(page))
	207	goto fail;
	208	}
2ba466d7 YA	209	}
	210	return page;
	211
	212	fail:
	213	nilfs_put_page(page);
	214	return ERR_PTR(-EIO);
	215	}
	216
	217	/*
	218	* NOTE! unlike strncmp, nilfs_match returns 1 for success, 0 for failure.
	219	*
	220	* len <= NILFS_NAME_LEN and de != NULL are guaranteed by caller.
	221	*/
	222	static int
072f98b4	223	nilfs_match(int len, const unsigned char name, struct nilfs_dir_entry de)
2ba466d7 YA	224	{
	225	if (len != de->name_len)
	226	return 0;
	227	if (!de->inode)
	228	return 0;
	229	return !memcmp(name, de->name, len);
	230	}
	231
	232	/*
	233	* p is at least 6 bytes before the end of page
	234	*/
	235	static struct nilfs_dir_entry nilfs_next_entry(struct nilfs_dir_entry p)
	236	{
6cda9fa2 RK	237	return (struct nilfs_dir_entry )((char )p +
6cda9fa2 RK	238	nilfs_rec_len_from_disk(p->rec_len));
2ba466d7 YA	239	}
	240
	241	static unsigned char
	242	nilfs_filetype_table[NILFS_FT_MAX] = {
	243	[NILFS_FT_UNKNOWN] = DT_UNKNOWN,
	244	[NILFS_FT_REG_FILE] = DT_REG,
	245	[NILFS_FT_DIR] = DT_DIR,
	246	[NILFS_FT_CHRDEV] = DT_CHR,
	247	[NILFS_FT_BLKDEV] = DT_BLK,
	248	[NILFS_FT_FIFO] = DT_FIFO,
	249	[NILFS_FT_SOCK] = DT_SOCK,
	250	[NILFS_FT_SYMLINK] = DT_LNK,
	251	};
	252
	253	#define S_SHIFT 12
	254	static unsigned char
	255	nilfs_type_by_mode[S_IFMT >> S_SHIFT] = {
	256	[S_IFREG >> S_SHIFT] = NILFS_FT_REG_FILE,
	257	[S_IFDIR >> S_SHIFT] = NILFS_FT_DIR,
	258	[S_IFCHR >> S_SHIFT] = NILFS_FT_CHRDEV,
	259	[S_IFBLK >> S_SHIFT] = NILFS_FT_BLKDEV,
	260	[S_IFIFO >> S_SHIFT] = NILFS_FT_FIFO,
	261	[S_IFSOCK >> S_SHIFT] = NILFS_FT_SOCK,
	262	[S_IFLNK >> S_SHIFT] = NILFS_FT_SYMLINK,
	263	};
	264
	265	static void nilfs_set_de_type(struct nilfs_dir_entry de, struct inode inode)
	266	{
c6e49e3f	267	umode_t mode = inode->i_mode;
2ba466d7 YA	268
	269	de->file_type = nilfs_type_by_mode[(mode & S_IFMT)>>S_SHIFT];
	270	}
	271
1616abe8	272	static int nilfs_readdir(struct file file, struct dir_context ctx)
2ba466d7	273	{
1616abe8 AV	274	loff_t pos = ctx->pos;
1616abe8 AV	275	struct inode *inode = file_inode(file);
2ba466d7	276	struct super_block *sb = inode->i_sb;
09cbfeaf KS	277	unsigned int offset = pos & ~PAGE_MASK;
09cbfeaf KS	278	unsigned long n = pos >> PAGE_SHIFT;
2ba466d7	279	unsigned long npages = dir_pages(inode);
2ba466d7 YA	280
2ba466d7 YA	281	if (pos > inode->i_size - NILFS_DIR_REC_LEN(1))
1616abe8	282	return 0;
2ba466d7 YA	283
	284	for ( ; n < npages; n++, offset = 0) {
	285	char kaddr, limit;
	286	struct nilfs_dir_entry *de;
	287	struct page *page = nilfs_get_page(inode, n);
	288
	289	if (IS_ERR(page)) {
cae3d4ca	290	nilfs_error(sb, "bad page in #%lu", inode->i_ino);
09cbfeaf	291	ctx->pos += PAGE_SIZE - offset;
1616abe8	292	return -EIO;
2ba466d7 YA	293	}
	294	kaddr = page_address(page);
	295	de = (struct nilfs_dir_entry *)(kaddr + offset);
	296	limit = kaddr + nilfs_last_byte(inode, n) -
	297	NILFS_DIR_REC_LEN(1);
	298	for ( ; (char *)de <= limit; de = nilfs_next_entry(de)) {
	299	if (de->rec_len == 0) {
cae3d4ca	300	nilfs_error(sb, "zero-length directory entry");
2ba466d7	301	nilfs_put_page(page);
1616abe8	302	return -EIO;
2ba466d7 YA	303	}
2ba466d7 YA	304	if (de->inode) {
1616abe8	305	unsigned char t;
2ba466d7	306
1616abe8 AV	307	if (de->file_type < NILFS_FT_MAX)
	308	t = nilfs_filetype_table[de->file_type];
	309	else
	310	t = DT_UNKNOWN;
2ba466d7	311
1616abe8 AV	312	if (!dir_emit(ctx, de->name, de->name_len,
1616abe8 AV	313	le64_to_cpu(de->inode), t)) {
2ba466d7	314	nilfs_put_page(page);
1616abe8	315	return 0;
2ba466d7 YA	316	}
2ba466d7 YA	317	}
1616abe8	318	ctx->pos += nilfs_rec_len_from_disk(de->rec_len);
2ba466d7 YA	319	}
	320	nilfs_put_page(page);
	321	}
1616abe8	322	return 0;
2ba466d7 YA	323	}
	324
	325	/*
	326	* nilfs_find_entry()
	327	*
	328	* finds an entry in the specified directory with the wanted name. It
	329	* returns the page in which the entry was found, and the entry itself
	330	* (as a parameter - res_dir). Page is returned mapped and unlocked.
	331	* Entry is guaranteed to be valid.
	332	*/
	333	struct nilfs_dir_entry *
0319003d	334	nilfs_find_entry(struct inode dir, const struct qstr qstr,
2ba466d7 YA	335	struct page **res_page)
2ba466d7 YA	336	{
0319003d AV	337	const unsigned char *name = qstr->name;
0319003d AV	338	int namelen = qstr->len;
0c6c44cb	339	unsigned int reclen = NILFS_DIR_REC_LEN(namelen);
2ba466d7 YA	340	unsigned long start, n;
	341	unsigned long npages = dir_pages(dir);
	342	struct page *page = NULL;
	343	struct nilfs_inode_info *ei = NILFS_I(dir);
	344	struct nilfs_dir_entry *de;
	345
	346	if (npages == 0)
	347	goto out;
	348
	349	/* OFFSET_CACHE */
	350	*res_page = NULL;
	351
	352	start = ei->i_dir_start_lookup;
	353	if (start >= npages)
	354	start = 0;
	355	n = start;
	356	do {
	357	char *kaddr;
4ad364ca	358
2ba466d7 YA	359	page = nilfs_get_page(dir, n);
	360	if (!IS_ERR(page)) {
	361	kaddr = page_address(page);
	362	de = (struct nilfs_dir_entry *)kaddr;
	363	kaddr += nilfs_last_byte(dir, n) - reclen;
	364	while ((char *) de <= kaddr) {
	365	if (de->rec_len == 0) {
cae3d4ca	366	nilfs_error(dir->i_sb,
2ba466d7 YA	367	"zero-length directory entry");
	368	nilfs_put_page(page);
	369	goto out;
	370	}
	371	if (nilfs_match(namelen, name, de))
	372	goto found;
	373	de = nilfs_next_entry(de);
	374	}
	375	nilfs_put_page(page);
	376	}
	377	if (++n >= npages)
	378	n = 0;
	379	/* next page is past the blocks we've got */
09cbfeaf	380	if (unlikely(n > (dir->i_blocks >> (PAGE_SHIFT - 9)))) {
cae3d4ca	381	nilfs_error(dir->i_sb,
1621562b	382	"dir %lu size %lld exceeds block count %llu",
2ba466d7 YA	383	dir->i_ino, dir->i_size,
	384	(unsigned long long)dir->i_blocks);
	385	goto out;
	386	}
	387	} while (n != start);
	388	out:
	389	return NULL;
	390
	391	found:
	392	*res_page = page;
	393	ei->i_dir_start_lookup = n;
	394	return de;
	395	}
	396
	397	struct nilfs_dir_entry nilfs_dotdot(struct inode dir, struct page **p)
	398	{
	399	struct page *page = nilfs_get_page(dir, 0);
	400	struct nilfs_dir_entry *de = NULL;
	401
	402	if (!IS_ERR(page)) {
	403	de = nilfs_next_entry(
	404	(struct nilfs_dir_entry *)page_address(page));
	405	*p = page;
	406	}
	407	return de;
	408	}
	409
0319003d	410	ino_t nilfs_inode_by_name(struct inode dir, const struct qstr qstr)
2ba466d7 YA	411	{
	412	ino_t res = 0;
	413	struct nilfs_dir_entry *de;
	414	struct page *page;
	415
0319003d	416	de = nilfs_find_entry(dir, qstr, &page);
2ba466d7 YA	417	if (de) {
	418	res = le64_to_cpu(de->inode);
	419	kunmap(page);
09cbfeaf	420	put_page(page);
2ba466d7 YA	421	}
	422	return res;
	423	}
	424
	425	/* Releases the page */
	426	void nilfs_set_link(struct inode dir, struct nilfs_dir_entry de,
	427	struct page page, struct inode inode)
	428	{
0c6c44cb RK	429	unsigned int from = (char )de - (char )page_address(page);
0c6c44cb RK	430	unsigned int to = from + nilfs_rec_len_from_disk(de->rec_len);
2ba466d7 YA	431	struct address_space *mapping = page->mapping;
	432	int err;
	433
	434	lock_page(page);
f4e420dc	435	err = nilfs_prepare_chunk(page, from, to);
2ba466d7 YA	436	BUG_ON(err);
	437	de->inode = cpu_to_le64(inode->i_ino);
	438	nilfs_set_de_type(de, inode);
2093abf9	439	nilfs_commit_chunk(page, mapping, from, to);
2ba466d7 YA	440	nilfs_put_page(page);
2ba466d7 YA	441	dir->i_mtime = dir->i_ctime = CURRENT_TIME;
2ba466d7 YA	442	}
	443
	444	/*
	445	* Parent is locked.
	446	*/
	447	int nilfs_add_link(struct dentry dentry, struct inode inode)
	448	{
2b0143b5	449	struct inode *dir = d_inode(dentry->d_parent);
072f98b4	450	const unsigned char *name = dentry->d_name.name;
2ba466d7	451	int namelen = dentry->d_name.len;
0c6c44cb RK	452	unsigned int chunk_size = nilfs_chunk_size(dir);
0c6c44cb RK	453	unsigned int reclen = NILFS_DIR_REC_LEN(namelen);
2ba466d7 YA	454	unsigned short rec_len, name_len;
	455	struct page *page = NULL;
	456	struct nilfs_dir_entry *de;
	457	unsigned long npages = dir_pages(dir);
	458	unsigned long n;
	459	char *kaddr;
0c6c44cb	460	unsigned int from, to;
2ba466d7 YA	461	int err;
	462
	463	/*
	464	* We take care of directory expansion in the same loop.
	465	* This code plays outside i_size, so it locks the page
	466	* to protect that region.
	467	*/
	468	for (n = 0; n <= npages; n++) {
	469	char *dir_end;
	470
	471	page = nilfs_get_page(dir, n);
	472	err = PTR_ERR(page);
	473	if (IS_ERR(page))
	474	goto out;
	475	lock_page(page);
	476	kaddr = page_address(page);
	477	dir_end = kaddr + nilfs_last_byte(dir, n);
	478	de = (struct nilfs_dir_entry *)kaddr;
09cbfeaf	479	kaddr += PAGE_SIZE - reclen;
2ba466d7 YA	480	while ((char *)de <= kaddr) {
	481	if ((char *)de == dir_end) {
	482	/* We hit i_size */
	483	name_len = 0;
	484	rec_len = chunk_size;
6cda9fa2	485	de->rec_len = nilfs_rec_len_to_disk(chunk_size);
2ba466d7 YA	486	de->inode = 0;
	487	goto got_it;
	488	}
	489	if (de->rec_len == 0) {
cae3d4ca	490	nilfs_error(dir->i_sb,
2ba466d7 YA	491	"zero-length directory entry");
	492	err = -EIO;
	493	goto out_unlock;
	494	}
	495	err = -EEXIST;
	496	if (nilfs_match(namelen, name, de))
	497	goto out_unlock;
	498	name_len = NILFS_DIR_REC_LEN(de->name_len);
6cda9fa2	499	rec_len = nilfs_rec_len_from_disk(de->rec_len);
2ba466d7 YA	500	if (!de->inode && rec_len >= reclen)
	501	goto got_it;
	502	if (rec_len >= name_len + reclen)
	503	goto got_it;
	504	de = (struct nilfs_dir_entry )((char )de + rec_len);
	505	}
	506	unlock_page(page);
	507	nilfs_put_page(page);
	508	}
	509	BUG();
	510	return -EINVAL;
	511
	512	got_it:
	513	from = (char )de - (char )page_address(page);
	514	to = from + rec_len;
f4e420dc	515	err = nilfs_prepare_chunk(page, from, to);
2ba466d7 YA	516	if (err)
	517	goto out_unlock;
	518	if (de->inode) {
	519	struct nilfs_dir_entry *de1;
	520
	521	de1 = (struct nilfs_dir_entry )((char )de + name_len);
6cda9fa2 RK	522	de1->rec_len = nilfs_rec_len_to_disk(rec_len - name_len);
6cda9fa2 RK	523	de->rec_len = nilfs_rec_len_to_disk(name_len);
2ba466d7 YA	524	de = de1;
	525	}
	526	de->name_len = namelen;
	527	memcpy(de->name, name, namelen);
	528	de->inode = cpu_to_le64(inode->i_ino);
	529	nilfs_set_de_type(de, inode);
2093abf9	530	nilfs_commit_chunk(page, page->mapping, from, to);
2ba466d7	531	dir->i_mtime = dir->i_ctime = CURRENT_TIME;
abdb318b	532	nilfs_mark_inode_dirty(dir);
2ba466d7 YA	533	/* OFFSET_CACHE */
	534	out_put:
	535	nilfs_put_page(page);
	536	out:
	537	return err;
	538	out_unlock:
	539	unlock_page(page);
	540	goto out_put;
	541	}
	542
	543	/*
	544	* nilfs_delete_entry deletes a directory entry by merging it with the
	545	* previous entry. Page is up-to-date. Releases the page.
	546	*/
	547	int nilfs_delete_entry(struct nilfs_dir_entry dir, struct page page)
	548	{
	549	struct address_space *mapping = page->mapping;
	550	struct inode *inode = mapping->host;
	551	char *kaddr = page_address(page);
0c6c44cb RK	552	unsigned int from, to;
0c6c44cb RK	553	struct nilfs_dir_entry de, pde = NULL;
2ba466d7 YA	554	int err;
2ba466d7 YA	555
0c6c44cb RK	556	from = ((char *)dir - kaddr) & ~(nilfs_chunk_size(inode) - 1);
	557	to = ((char *)dir - kaddr) + nilfs_rec_len_from_disk(dir->rec_len);
	558	de = (struct nilfs_dir_entry *)(kaddr + from);
	559
2ba466d7 YA	560	while ((char )de < (char )dir) {
2ba466d7 YA	561	if (de->rec_len == 0) {
cae3d4ca	562	nilfs_error(inode->i_sb,
2ba466d7 YA	563	"zero-length directory entry");
	564	err = -EIO;
	565	goto out;
	566	}
	567	pde = de;
	568	de = nilfs_next_entry(de);
	569	}
	570	if (pde)
	571	from = (char )pde - (char )page_address(page);
	572	lock_page(page);
f4e420dc	573	err = nilfs_prepare_chunk(page, from, to);
2ba466d7 YA	574	BUG_ON(err);
2ba466d7 YA	575	if (pde)
6cda9fa2	576	pde->rec_len = nilfs_rec_len_to_disk(to - from);
2ba466d7	577	dir->inode = 0;
2093abf9	578	nilfs_commit_chunk(page, mapping, from, to);
2ba466d7	579	inode->i_ctime = inode->i_mtime = CURRENT_TIME;
2ba466d7 YA	580	out:
	581	nilfs_put_page(page);
	582	return err;
	583	}
	584
	585	/*
	586	* Set the first fragment of directory.
	587	*/
	588	int nilfs_make_empty(struct inode inode, struct inode parent)
	589	{
	590	struct address_space *mapping = inode->i_mapping;
	591	struct page *page = grab_cache_page(mapping, 0);
0c6c44cb	592	unsigned int chunk_size = nilfs_chunk_size(inode);
2ba466d7 YA	593	struct nilfs_dir_entry *de;
	594	int err;
	595	void *kaddr;
	596
	597	if (!page)
	598	return -ENOMEM;
	599
f4e420dc	600	err = nilfs_prepare_chunk(page, 0, chunk_size);
2ba466d7 YA	601	if (unlikely(err)) {
	602	unlock_page(page);
	603	goto fail;
	604	}
7b9c0976	605	kaddr = kmap_atomic(page);
2ba466d7 YA	606	memset(kaddr, 0, chunk_size);
	607	de = (struct nilfs_dir_entry *)kaddr;
	608	de->name_len = 1;
6cda9fa2	609	de->rec_len = nilfs_rec_len_to_disk(NILFS_DIR_REC_LEN(1));
2ba466d7 YA	610	memcpy(de->name, ".\0\0", 4);
	611	de->inode = cpu_to_le64(inode->i_ino);
	612	nilfs_set_de_type(de, inode);
	613
	614	de = (struct nilfs_dir_entry *)(kaddr + NILFS_DIR_REC_LEN(1));
	615	de->name_len = 2;
6cda9fa2	616	de->rec_len = nilfs_rec_len_to_disk(chunk_size - NILFS_DIR_REC_LEN(1));
2ba466d7 YA	617	de->inode = cpu_to_le64(parent->i_ino);
	618	memcpy(de->name, "..\0", 4);
	619	nilfs_set_de_type(de, inode);
7b9c0976	620	kunmap_atomic(kaddr);
2093abf9	621	nilfs_commit_chunk(page, mapping, 0, chunk_size);
2ba466d7	622	fail:
09cbfeaf	623	put_page(page);
2ba466d7 YA	624	return err;
	625	}
	626
	627	/*
	628	* routine to check that the specified directory is empty (for rmdir)
	629	*/
	630	int nilfs_empty_dir(struct inode *inode)
	631	{
	632	struct page *page = NULL;
	633	unsigned long i, npages = dir_pages(inode);
	634
	635	for (i = 0; i < npages; i++) {
	636	char *kaddr;
	637	struct nilfs_dir_entry *de;
	638
	639	page = nilfs_get_page(inode, i);
	640	if (IS_ERR(page))
	641	continue;
	642
	643	kaddr = page_address(page);
	644	de = (struct nilfs_dir_entry *)kaddr;
	645	kaddr += nilfs_last_byte(inode, i) - NILFS_DIR_REC_LEN(1);
	646
	647	while ((char *)de <= kaddr) {
	648	if (de->rec_len == 0) {
cae3d4ca	649	nilfs_error(inode->i_sb,
06f4abf6 RK	650	"zero-length directory entry (kaddr=%p, de=%p)",
06f4abf6 RK	651	kaddr, de);
2ba466d7 YA	652	goto not_empty;
	653	}
	654	if (de->inode != 0) {
	655	/* check for . and .. */
	656	if (de->name[0] != '.')
	657	goto not_empty;
	658	if (de->name_len > 2)
	659	goto not_empty;
	660	if (de->name_len < 2) {
	661	if (de->inode !=
	662	cpu_to_le64(inode->i_ino))
	663	goto not_empty;
	664	} else if (de->name[1] != '.')
	665	goto not_empty;
	666	}
	667	de = nilfs_next_entry(de);
	668	}
	669	nilfs_put_page(page);
	670	}
	671	return 1;
	672
	673	not_empty:
	674	nilfs_put_page(page);
	675	return 0;
	676	}
	677
828c0950	678	const struct file_operations nilfs_dir_operations = {
2ba466d7 YA	679	.llseek = generic_file_llseek,
2ba466d7 YA	680	.read = generic_read_dir,
c51da20c	681	.iterate_shared = nilfs_readdir,
7a946193	682	.unlocked_ioctl = nilfs_ioctl,
2ba466d7	683	#ifdef CONFIG_COMPAT
828b1c50	684	.compat_ioctl = nilfs_compat_ioctl,
2ba466d7 YA	685	#endif /* CONFIG_COMPAT */
	686	.fsync = nilfs_sync_file,
	687
	688	};