Initial import

1 files changed, 730 insertions, 0 deletions

diff --git a/fs/ext2/dir.c b/fs/ext2/dir.c
new file mode 100644
index 000000000..796b491e6
--- /dev/null
+++ b/fs/ext2/dir.c
@@ -0,0 +1,730 @@
+/*
+ *  linux/fs/ext2/dir.c
+ *
+ * Copyright (C) 1992, 1993, 1994, 1995
+ * Remy Card (card@masi.ibp.fr)
+ * 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 (davem@caip.rutgers.edu), 1995
+ *
+ * All code that works with directory layout had been switched to pagecache
+ * and moved here. AV
+ */
+
+#include "ext2.h"
+#include <linux/buffer_head.h>
+#include <linux/pagemap.h>
+#include <linux/swap.h>
+
+typedef struct ext2_dir_entry_2 ext2_dirent;
+
+/*
+ * Tests against MAX_REC_LEN etc were put in place for 64k block
+ * sizes; if that is not possible on this arch, we can skip
+ * those tests and speed things up.
+ */
+static inline unsigned ext2_rec_len_from_disk(__le16 dlen)
+{
+	unsigned len = le16_to_cpu(dlen);
+
+#if (PAGE_CACHE_SIZE >= 65536)
+	if (len == EXT2_MAX_REC_LEN)
+		return 1 << 16;
+#endif
+	return len;
+}
+
+static inline __le16 ext2_rec_len_to_disk(unsigned len)
+{
+#if (PAGE_CACHE_SIZE >= 65536)
+	if (len == (1 << 16))
+		return cpu_to_le16(EXT2_MAX_REC_LEN);
+	else
+		BUG_ON(len > (1 << 16));
+#endif
+	return cpu_to_le16(len);
+}
+
+/*
+ * ext2 uses block-sized chunks. Arguably, sector-sized ones would be
+ * more robust, but we have what we have
+ */
+static inline unsigned ext2_chunk_size(struct inode *inode)
+{
+	return inode->i_sb->s_blocksize;
+}
+
+static inline void ext2_put_page(struct page *page)
+{
+	kunmap(page);
+	page_cache_release(page);
+}
+
+static inline unsigned long dir_pages(struct inode *inode)
+{
+	return (inode->i_size+PAGE_CACHE_SIZE-1)>>PAGE_CACHE_SHIFT;
+}
+
+/*
+ * Return the offset into page `page_nr' of the last valid
+ * byte in that page, plus one.
+ */
+static unsigned
+ext2_last_byte(struct inode *inode, unsigned long page_nr)
+{
+	unsigned last_byte = inode->i_size;
+
+	last_byte -= page_nr << PAGE_CACHE_SHIFT;
+	if (last_byte > PAGE_CACHE_SIZE)
+		last_byte = PAGE_CACHE_SIZE;
+	return last_byte;
+}
+
+static int ext2_commit_chunk(struct page *page, loff_t pos, unsigned len)
+{
+	struct address_space *mapping = page->mapping;
+	struct inode *dir = mapping->host;
+	int err = 0;
+
+	dir->i_version++;
+	block_write_end(NULL, mapping, pos, len, len, page, NULL);
+
+	if (pos+len > dir->i_size) {
+		i_size_write(dir, pos+len);
+		mark_inode_dirty(dir);
+	}
+
+	if (IS_DIRSYNC(dir)) {
+		err = write_one_page(page, 1);
+		if (!err)
+			err = sync_inode_metadata(dir, 1);
+	} else {
+		unlock_page(page);
+	}
+
+	return err;
+}
+
+static void ext2_check_page(struct page *page, int quiet)
+{
+	struct inode *dir = page->mapping->host;
+	struct super_block *sb = dir->i_sb;
+	unsigned chunk_size = ext2_chunk_size(dir);
+	char *kaddr = page_address(page);
+	u32 max_inumber = le32_to_cpu(EXT2_SB(sb)->s_es->s_inodes_count);
+	unsigned offs, rec_len;
+	unsigned limit = PAGE_CACHE_SIZE;
+	ext2_dirent *p;
+	char *error;
+
+	if ((dir->i_size >> PAGE_CACHE_SHIFT) == page->index) {
+		limit = dir->i_size & ~PAGE_CACHE_MASK;
+		if (limit & (chunk_size - 1))
+			goto Ebadsize;
+		if (!limit)
+			goto out;
+	}
+	for (offs = 0; offs <= limit - EXT2_DIR_REC_LEN(1); offs += rec_len) {
+		p = (ext2_dirent *)(kaddr + offs);
+		rec_len = ext2_rec_len_from_disk(p->rec_len);
+
+		if (unlikely(rec_len < EXT2_DIR_REC_LEN(1)))
+			goto Eshort;
+		if (unlikely(rec_len & 3))
+			goto Ealign;
+		if (unlikely(rec_len < EXT2_DIR_REC_LEN(p->name_len)))
+			goto Enamelen;
+		if (unlikely(((offs + rec_len - 1) ^ offs) & ~(chunk_size-1)))
+			goto Espan;
+		if (unlikely(le32_to_cpu(p->inode) > max_inumber))
+			goto Einumber;
+	}
+	if (offs != limit)
+		goto Eend;
+out:
+	SetPageChecked(page);
+	return;
+
+	/* Too bad, we had an error */
+
+Ebadsize:
+	if (!quiet)
+		ext2_error(sb, __func__,
+			"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";
+	goto bad_entry;
+Einumber:
+	error = "inode out of bounds";
+bad_entry:
+	if (!quiet)
+		ext2_error(sb, __func__, "bad entry in directory #%lu: : %s - "
+			"offset=%lu, inode=%lu, rec_len=%d, name_len=%d",
+			dir->i_ino, error, (page->index<<PAGE_CACHE_SHIFT)+offs,
+			(unsigned long) le32_to_cpu(p->inode),
+			rec_len, p->name_len);
+	goto fail;
+Eend:
+	if (!quiet) {
+		p = (ext2_dirent *)(kaddr + offs);
+		ext2_error(sb, "ext2_check_page",
+			"entry in directory #%lu spans the page boundary"
+			"offset=%lu, inode=%lu",
+			dir->i_ino, (page->index<<PAGE_CACHE_SHIFT)+offs,
+			(unsigned long) le32_to_cpu(p->inode));
+	}
+fail:
+	SetPageChecked(page);
+	SetPageError(page);
+}
+
+static struct page * ext2_get_page(struct inode *dir, unsigned long n,
+				   int quiet)
+{
+	struct address_space *mapping = dir->i_mapping;
+	struct page *page = read_mapping_page(mapping, n, NULL);
+	if (!IS_ERR(page)) {
+		kmap(page);
+		if (!PageChecked(page))
+			ext2_check_page(page, quiet);
+		if (PageError(page))
+			goto fail;
+	}
+	return page;
+
+fail:
+	ext2_put_page(page);
+	return ERR_PTR(-EIO);
+}
+
+/*
+ * NOTE! unlike strncmp, ext2_match returns 1 for success, 0 for failure.
+ *
+ * len <= EXT2_NAME_LEN and de != NULL are guaranteed by caller.
+ */
+static inline int ext2_match (int len, const char * const name,
+					struct ext2_dir_entry_2 * 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 inline ext2_dirent *ext2_next_entry(ext2_dirent *p)
+{
+	return (ext2_dirent *)((char *)p +
+			ext2_rec_len_from_disk(p->rec_len));
+}
+
+static inline unsigned 
+ext2_validate_entry(char *base, unsigned offset, unsigned mask)
+{
+	ext2_dirent *de = (ext2_dirent*)(base + offset);
+	ext2_dirent *p = (ext2_dirent*)(base + (offset&mask));
+	while ((char*)p < (char*)de) {
+		if (p->rec_len == 0)
+			break;
+		p = ext2_next_entry(p);
+	}
+	return (char *)p - base;
+}
+
+static unsigned char ext2_filetype_table[EXT2_FT_MAX] = {
+	[EXT2_FT_UNKNOWN]	= DT_UNKNOWN,
+	[EXT2_FT_REG_FILE]	= DT_REG,
+	[EXT2_FT_DIR]		= DT_DIR,
+	[EXT2_FT_CHRDEV]	= DT_CHR,
+	[EXT2_FT_BLKDEV]	= DT_BLK,
+	[EXT2_FT_FIFO]		= DT_FIFO,
+	[EXT2_FT_SOCK]		= DT_SOCK,
+	[EXT2_FT_SYMLINK]	= DT_LNK,
+};
+
+#define S_SHIFT 12
+static unsigned char ext2_type_by_mode[S_IFMT >> S_SHIFT] = {
+	[S_IFREG >> S_SHIFT]	= EXT2_FT_REG_FILE,
+	[S_IFDIR >> S_SHIFT]	= EXT2_FT_DIR,
+	[S_IFCHR >> S_SHIFT]	= EXT2_FT_CHRDEV,
+	[S_IFBLK >> S_SHIFT]	= EXT2_FT_BLKDEV,
+	[S_IFIFO >> S_SHIFT]	= EXT2_FT_FIFO,
+	[S_IFSOCK >> S_SHIFT]	= EXT2_FT_SOCK,
+	[S_IFLNK >> S_SHIFT]	= EXT2_FT_SYMLINK,
+};
+
+static inline void ext2_set_de_type(ext2_dirent *de, struct inode *inode)
+{
+	umode_t mode = inode->i_mode;
+	if (EXT2_HAS_INCOMPAT_FEATURE(inode->i_sb, EXT2_FEATURE_INCOMPAT_FILETYPE))
+		de->file_type = ext2_type_by_mode[(mode & S_IFMT)>>S_SHIFT];
+	else
+		de->file_type = 0;
+}
+
+static int
+ext2_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_CACHE_MASK;
+	unsigned long n = pos >> PAGE_CACHE_SHIFT;
+	unsigned long npages = dir_pages(inode);
+	unsigned chunk_mask = ~(ext2_chunk_size(inode)-1);
+	unsigned char *types = NULL;
+	int need_revalidate = file->f_version != inode->i_version;
+
+	if (pos > inode->i_size - EXT2_DIR_REC_LEN(1))
+		return 0;
+
+	if (EXT2_HAS_INCOMPAT_FEATURE(sb, EXT2_FEATURE_INCOMPAT_FILETYPE))
+		types = ext2_filetype_table;
+
+	for ( ; n < npages; n++, offset = 0) {
+		char *kaddr, *limit;
+		ext2_dirent *de;
+		struct page *page = ext2_get_page(inode, n, 0);
+
+		if (IS_ERR(page)) {
+			ext2_error(sb, __func__,
+				   "bad page in #%lu",
+				   inode->i_ino);
+			ctx->pos += PAGE_CACHE_SIZE - offset;
+			return PTR_ERR(page);
+		}
+		kaddr = page_address(page);
+		if (unlikely(need_revalidate)) {
+			if (offset) {
+				offset = ext2_validate_entry(kaddr, offset, chunk_mask);
+				ctx->pos = (n<<PAGE_CACHE_SHIFT) + offset;
+			}
+			file->f_version = inode->i_version;
+			need_revalidate = 0;
+		}
+		de = (ext2_dirent *)(kaddr+offset);
+		limit = kaddr + ext2_last_byte(inode, n) - EXT2_DIR_REC_LEN(1);
+		for ( ;(char*)de <= limit; de = ext2_next_entry(de)) {
+			if (de->rec_len == 0) {
+				ext2_error(sb, __func__,
+					"zero-length directory entry");
+				ext2_put_page(page);
+				return -EIO;
+			}
+			if (de->inode) {
+				unsigned char d_type = DT_UNKNOWN;
+
+				if (types && de->file_type < EXT2_FT_MAX)
+					d_type = types[de->file_type];
+
+				if (!dir_emit(ctx, de->name, de->name_len,
+						le32_to_cpu(de->inode),
+						d_type)) {
+					ext2_put_page(page);
+					return 0;
+				}
+			}
+			ctx->pos += ext2_rec_len_from_disk(de->rec_len);
+		}
+		ext2_put_page(page);
+	}
+	return 0;
+}
+
+/*
+ *	ext2_find_entry()
+ *
+ * finds an entry in the specified directory with the wanted name. It
+ * returns the page in which the entry was found (as a parameter - res_page),
+ * and the entry itself. Page is returned mapped and unlocked.
+ * Entry is guaranteed to be valid.
+ */
+struct ext2_dir_entry_2 *ext2_find_entry (struct inode * dir,
+			struct qstr *child, struct page ** res_page)
+{
+	const char *name = child->name;
+	int namelen = child->len;
+	unsigned reclen = EXT2_DIR_REC_LEN(namelen);
+	unsigned long start, n;
+	unsigned long npages = dir_pages(dir);
+	struct page *page = NULL;
+	struct ext2_inode_info *ei = EXT2_I(dir);
+	ext2_dirent * de;
+	int dir_has_error = 0;
+
+	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 = ext2_get_page(dir, n, dir_has_error);
+		if (!IS_ERR(page)) {
+			kaddr = page_address(page);
+			de = (ext2_dirent *) kaddr;
+			kaddr += ext2_last_byte(dir, n) - reclen;
+			while ((char *) de <= kaddr) {
+				if (de->rec_len == 0) {
+					ext2_error(dir->i_sb, __func__,
+						"zero-length directory entry");
+					ext2_put_page(page);
+					goto out;
+				}
+				if (ext2_match (namelen, name, de))
+					goto found;
+				de = ext2_next_entry(de);
+			}
+			ext2_put_page(page);
+		} else
+			dir_has_error = 1;
+
+		if (++n >= npages)
+			n = 0;
+		/* next page is past the blocks we've got */
+		if (unlikely(n > (dir->i_blocks >> (PAGE_CACHE_SHIFT - 9)))) {
+			ext2_error(dir->i_sb, __func__,
+				"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 ext2_dir_entry_2 * ext2_dotdot (struct inode *dir, struct page **p)
+{
+	struct page *page = ext2_get_page(dir, 0, 0);
+	ext2_dirent *de = NULL;
+
+	if (!IS_ERR(page)) {
+		de = ext2_next_entry((ext2_dirent *) page_address(page));
+		*p = page;
+	}
+	return de;
+}
+
+ino_t ext2_inode_by_name(struct inode *dir, struct qstr *child)
+{
+	ino_t res = 0;
+	struct ext2_dir_entry_2 *de;
+	struct page *page;
+	
+	de = ext2_find_entry (dir, child, &page);
+	if (de) {
+		res = le32_to_cpu(de->inode);
+		ext2_put_page(page);
+	}
+	return res;
+}
+
+static int ext2_prepare_chunk(struct page *page, loff_t pos, unsigned len)
+{
+	return __block_write_begin(page, pos, len, ext2_get_block);
+}
+
+/* Releases the page */
+void ext2_set_link(struct inode *dir, struct ext2_dir_entry_2 *de,
+		   struct page *page, struct inode *inode, int update_times)
+{
+	loff_t pos = page_offset(page) +
+			(char *) de - (char *) page_address(page);
+	unsigned len = ext2_rec_len_from_disk(de->rec_len);
+	int err;
+
+	lock_page(page);
+	err = ext2_prepare_chunk(page, pos, len);
+	BUG_ON(err);
+	de->inode = cpu_to_le32(inode->i_ino);
+	ext2_set_de_type(de, inode);
+	err = ext2_commit_chunk(page, pos, len);
+	ext2_put_page(page);
+	if (update_times)
+		dir->i_mtime = dir->i_ctime = CURRENT_TIME_SEC;
+	EXT2_I(dir)->i_flags &= ~EXT2_BTREE_FL;
+	mark_inode_dirty(dir);
+}
+
+/*
+ *	Parent is locked.
+ */
+int ext2_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;
+	unsigned chunk_size = ext2_chunk_size(dir);
+	unsigned reclen = EXT2_DIR_REC_LEN(namelen);
+	unsigned short rec_len, name_len;
+	struct page *page = NULL;
+	ext2_dirent * de;
+	unsigned long npages = dir_pages(dir);
+	unsigned long n;
+	char *kaddr;
+	loff_t pos;
+	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 = ext2_get_page(dir, n, 0);
+		err = PTR_ERR(page);
+		if (IS_ERR(page))
+			goto out;
+		lock_page(page);
+		kaddr = page_address(page);
+		dir_end = kaddr + ext2_last_byte(dir, n);
+		de = (ext2_dirent *)kaddr;
+		kaddr += PAGE_CACHE_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 = ext2_rec_len_to_disk(chunk_size);
+				de->inode = 0;
+				goto got_it;
+			}
+			if (de->rec_len == 0) {
+				ext2_error(dir->i_sb, __func__,
+					"zero-length directory entry");
+				err = -EIO;
+				goto out_unlock;
+			}
+			err = -EEXIST;
+			if (ext2_match (namelen, name, de))
+				goto out_unlock;
+			name_len = EXT2_DIR_REC_LEN(de->name_len);
+			rec_len = ext2_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 = (ext2_dirent *) ((char *) de + rec_len);
+		}
+		unlock_page(page);
+		ext2_put_page(page);
+	}
+	BUG();
+	return -EINVAL;
+
+got_it:
+	pos = page_offset(page) +
+		(char*)de - (char*)page_address(page);
+	err = ext2_prepare_chunk(page, pos, rec_len);
+	if (err)
+		goto out_unlock;
+	if (de->inode) {
+		ext2_dirent *de1 = (ext2_dirent *) ((char *) de + name_len);
+		de1->rec_len = ext2_rec_len_to_disk(rec_len - name_len);
+		de->rec_len = ext2_rec_len_to_disk(name_len);
+		de = de1;
+	}
+	de->name_len = namelen;
+	memcpy(de->name, name, namelen);
+	de->inode = cpu_to_le32(inode->i_ino);
+	ext2_set_de_type (de, inode);
+	err = ext2_commit_chunk(page, pos, rec_len);
+	dir->i_mtime = dir->i_ctime = CURRENT_TIME_SEC;
+	EXT2_I(dir)->i_flags &= ~EXT2_BTREE_FL;
+	mark_inode_dirty(dir);
+	/* OFFSET_CACHE */
+out_put:
+	ext2_put_page(page);
+out:
+	return err;
+out_unlock:
+	unlock_page(page);
+	goto out_put;
+}
+
+/*
+ * ext2_delete_entry deletes a directory entry by merging it with the
+ * previous entry. Page is up-to-date. Releases the page.
+ */
+int ext2_delete_entry (struct ext2_dir_entry_2 * dir, struct page * page )
+{
+	struct inode *inode = page->mapping->host;
+	char *kaddr = page_address(page);
+	unsigned from = ((char*)dir - kaddr) & ~(ext2_chunk_size(inode)-1);
+	unsigned to = ((char *)dir - kaddr) +
+				ext2_rec_len_from_disk(dir->rec_len);
+	loff_t pos;
+	ext2_dirent * pde = NULL;
+	ext2_dirent * de = (ext2_dirent *) (kaddr + from);
+	int err;
+
+	while ((char*)de < (char*)dir) {
+		if (de->rec_len == 0) {
+			ext2_error(inode->i_sb, __func__,
+				"zero-length directory entry");
+			err = -EIO;
+			goto out;
+		}
+		pde = de;
+		de = ext2_next_entry(de);
+	}
+	if (pde)
+		from = (char*)pde - (char*)page_address(page);
+	pos = page_offset(page) + from;
+	lock_page(page);
+	err = ext2_prepare_chunk(page, pos, to - from);
+	BUG_ON(err);
+	if (pde)
+		pde->rec_len = ext2_rec_len_to_disk(to - from);
+	dir->inode = 0;
+	err = ext2_commit_chunk(page, pos, to - from);
+	inode->i_ctime = inode->i_mtime = CURRENT_TIME_SEC;
+	EXT2_I(inode)->i_flags &= ~EXT2_BTREE_FL;
+	mark_inode_dirty(inode);
+out:
+	ext2_put_page(page);
+	return err;
+}
+
+/*
+ * Set the first fragment of directory.
+ */
+int ext2_make_empty(struct inode *inode, struct inode *parent)
+{
+	struct page *page = grab_cache_page(inode->i_mapping, 0);
+	unsigned chunk_size = ext2_chunk_size(inode);
+	struct ext2_dir_entry_2 * de;
+	int err;
+	void *kaddr;
+
+	if (!page)
+		return -ENOMEM;
+
+	err = ext2_prepare_chunk(page, 0, chunk_size);
+	if (err) {
+		unlock_page(page);
+		goto fail;
+	}
+	kaddr = kmap_atomic(page);
+	memset(kaddr, 0, chunk_size);
+	de = (struct ext2_dir_entry_2 *)kaddr;
+	de->name_len = 1;
+	de->rec_len = ext2_rec_len_to_disk(EXT2_DIR_REC_LEN(1));
+	memcpy (de->name, ".\0\0", 4);
+	de->inode = cpu_to_le32(inode->i_ino);
+	ext2_set_de_type (de, inode);
+
+	de = (struct ext2_dir_entry_2 *)(kaddr + EXT2_DIR_REC_LEN(1));
+	de->name_len = 2;
+	de->rec_len = ext2_rec_len_to_disk(chunk_size - EXT2_DIR_REC_LEN(1));
+	de->inode = cpu_to_le32(parent->i_ino);
+	memcpy (de->name, "..\0", 4);
+	ext2_set_de_type (de, inode);
+	kunmap_atomic(kaddr);
+	err = ext2_commit_chunk(page, 0, chunk_size);
+fail:
+	page_cache_release(page);
+	return err;
+}
+
+/*
+ * routine to check that the specified directory is empty (for rmdir)
+ */
+int ext2_empty_dir (struct inode * inode)
+{
+	struct page *page = NULL;
+	unsigned long i, npages = dir_pages(inode);
+	int dir_has_error = 0;
+
+	for (i = 0; i < npages; i++) {
+		char *kaddr;
+		ext2_dirent * de;
+		page = ext2_get_page(inode, i, dir_has_error);
+
+		if (IS_ERR(page)) {
+			dir_has_error = 1;
+			continue;
+		}
+
+		kaddr = page_address(page);
+		de = (ext2_dirent *)kaddr;
+		kaddr += ext2_last_byte(inode, i) - EXT2_DIR_REC_LEN(1);
+
+		while ((char *)de <= kaddr) {
+			if (de->rec_len == 0) {
+				ext2_error(inode->i_sb, __func__,
+					"zero-length directory entry");
+				printk("kaddr=%p, de=%p\n", 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_le32(inode->i_ino))
+						goto not_empty;
+				} else if (de->name[1] != '.')
+					goto not_empty;
+			}
+			de = ext2_next_entry(de);
+		}
+		ext2_put_page(page);
+	}
+	return 1;
+
+not_empty:
+	ext2_put_page(page);
+	return 0;
+}
+
+const struct file_operations ext2_dir_operations = {
+	.llseek		= generic_file_llseek,
+	.read		= generic_read_dir,
+	.iterate	= ext2_readdir,
+	.unlocked_ioctl = ext2_ioctl,
+#ifdef CONFIG_COMPAT
+	.compat_ioctl	= ext2_compat_ioctl,
+#endif
+	.fsync		= ext2_fsync,
+};