Merge tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-tracegrafted

Pull tracing fixes from Steven Rostedt:

 - Fix error output of boot instance creation failure

   Currently if a boot instance creation fails, instead of printing out
   the name of the instance that failed, it prints "(null)". That is
   because it prints "cur_str" that had already been processed by
   strsep(). Print the saved name instead.

   While at it, print the error code of the failure.

 - Fix use-after-free for same named historgrams

   Histograms can be named so that they can be used in multiple events.
   But if the named histogram has a variable attached, the second event
   that uses the named histogram which duplicates it and needs to free
   the original after duplication leaves the old variable in place and
   still visible. If another histogram uses than variable, it will use
   the stale one which will try to reference the freed duplicate
   histogram and crash the kernel.

   Free the duplicate variables along with the duplicated histogram
   data.

 - Check return value of kthread_run() in event self test

   The events self tests uses a kthread for testing but does not check
   if it succeeded in creating a kthread. If the kthread creation were
   to fail, the code will still try to call kthread_stop() on the error
   returned.

 - Fix race between reading trace_pipe and updating subbuffer size

   If a user is reading the trace_pipe file at the same time they update
   the ring buffer sub-buffer size, can cause the trace_pipe read to
   read stale data. Add trace_access_lock() around updating the ring
   buffer sub-buffer size.

 - Fix eventfs_inode on failure path in creation of the events directory

   In the creation of the "events" directory, if after allocating the
   eventfs_inode a failure is detected, it calls cleanup_ei() which
   calls free_ei(). The free_ei() will test if eventfs_inode being freed
   has no children. It is a bug if it does. But on the failure case of
   the creation of the "events" directory, the children lists have not
   yet been initialized and the free will trigger a warning because
   list_empty() on an uninitialized list returns false.

   Move the initialization into init_ei() where it makes more sense and
   makes sure that a created eventfs_inode has its lists initialized
   upon creation.

 - Check return value of kthread_run() in ftrace direct sample code

   The sample code that shows how to use the ftrace direct calls does
   not test the return of kthread_run() to see if it succeeds. Return a
   failure if the kthread_run() doesn't succeed.

 - Clear user events state on fork in case of alloc failure

   On fork, the child gets a pointer to the parent's user events state.
   It makes a copy of it then updates the child's pointer to it. But if
   the allocation fails, the duplication function leaves the child with
   a pointer to its parent's descriptor. When the child cleans up its
   data, it will free the parent's descriptor while the parent is still
   using it.

   In the duplication function, set the child's user_event_mm to NULL
   before testing if the allocation succeeded, and when it exits it will
   not free the parent's descriptor.

 - Fix retry exhaustion in simple ring buffer reader swap

   simple_ring_buffer_swap_reader_page() starts with retry set to 8 and
   post-decrements it only after a failed link replacement. On the final
   attempt, a successful replacement leaves retry at zero, while a
   failed replacement leaves it at -1.

   But the check for success expects the retry value to be non-zero and
   exits with an error on zero. This is the opposite result. Fix it.

 - Fail nicely when the remote swap_reader_page() returns an error

   Currently, if the swap_reader_page() of a remote buffer fails, it
   triggers a WARN_ON_ONCE() and continues normally. Instead, have it
   exit with an error and a pr_warn() print instead of a full WARNING.

* tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  ring-buffer: Stop remote reader update when page swap fails
  tracing: Fix retry exhaustion in simple ring buffer reader swap
  tracing/user_events: Clear copied tracing state before fork duplication
  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-multi-modify
  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-modify
  eventfs: Initialize ei->children and ei->list in init_ei()
  tracing: Fix use-after-free in trace_pipe read on sub-buffer order change
  tracing: Fix crash passing ERR_PTR to kthread_stop()
  tracing: Fix use-after-free with same-name named triggers
  tracing: Fix logged instance name on creation failure

1 files changed, 665 insertions, 0 deletions

diff --git a/fs/nilfs2/dir.c b/fs/nilfs2/dir.c
new file mode 100644
index 000000000..8b53802b6
--- /dev/null
+++ b/fs/nilfs2/dir.c
@@ -0,0 +1,665 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * NILFS directory entry operations
+ *
+ * Copyright (C) 2005-2008 Nippon Telegraph and Telephone Corporation.
+ *
+ * Modified for NILFS by Amagai Yoshiji.
+ */
+/*
+ *  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 <linux/pagemap.h>
+#include <linux/filelock.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;
+}
+
+/*
+ * 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)
+{
+	u64 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 folio *folio, unsigned int from,
+			       unsigned int to)
+{
+	loff_t pos = folio_pos(folio) + from;
+
+	return __block_write_begin(folio, pos, to - from, nilfs_get_block);
+}
+
+static void nilfs_commit_chunk(struct folio *folio,
+		struct address_space *mapping, size_t from, size_t to)
+{
+	struct inode *dir = mapping->host;
+	loff_t pos = folio_pos(folio) + from;
+	size_t copied, len = to - from;
+	unsigned int nr_dirty;
+	int err;
+
+	nr_dirty = nilfs_page_count_clean_buffers(folio, from, to);
+	copied = block_write_end(pos, len, len, folio);
+	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 */
+	folio_unlock(folio);
+}
+
+static bool nilfs_check_folio(struct folio *folio, char *kaddr)
+{
+	struct inode *dir = folio->mapping->host;
+	struct super_block *sb = dir->i_sb;
+	unsigned int chunk_size = nilfs_chunk_size(dir);
+	size_t offs, rec_len;
+	size_t limit = folio_size(folio);
+	struct nilfs_dir_entry *p;
+	char *error;
+
+	if (dir->i_size < folio_pos(folio) + limit) {
+		limit = dir->i_size - folio_pos(folio);
+		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 (unlikely(p->inode &&
+			     NILFS_PRIVATE_INODE(le64_to_cpu(p->inode))))
+			goto Einumber;
+	}
+	if (offs != limit)
+		goto Eend;
+out:
+	folio_set_checked(folio);
+	return true;
+
+	/* Too bad, we had an error */
+
+Ebadsize:
+	nilfs_error(sb,
+		    "size of directory #%llu 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 = "disallowed inode number";
+bad_entry:
+	nilfs_error(sb,
+		    "bad entry in directory #%llu: %s - offset=%lu, inode=%llu, rec_len=%zd, name_len=%d",
+		    dir->i_ino, error, (folio->index << PAGE_SHIFT) + offs,
+		    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 #%llu spans the page boundary offset=%lu, inode=%llu",
+		    dir->i_ino, (folio->index << PAGE_SHIFT) + offs,
+		    le64_to_cpu(p->inode));
+fail:
+	return false;
+}
+
+static void *nilfs_get_folio(struct inode *dir, unsigned long n,
+		struct folio **foliop)
+{
+	struct address_space *mapping = dir->i_mapping;
+	struct folio *folio = read_mapping_folio(mapping, n, NULL);
+	void *kaddr;
+
+	if (IS_ERR(folio))
+		return folio;
+
+	kaddr = kmap_local_folio(folio, 0);
+	if (unlikely(!folio_test_checked(folio))) {
+		if (!nilfs_check_folio(folio, kaddr))
+			goto fail;
+	}
+
+	*foliop = folio;
+	return kaddr;
+
+fail:
+	folio_release_kmap(folio, kaddr);
+	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 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 folio *folio;
+
+		kaddr = nilfs_get_folio(inode, n, &folio);
+		if (IS_ERR(kaddr)) {
+			nilfs_error(sb, "bad page in #%llu", inode->i_ino);
+			ctx->pos += PAGE_SIZE - offset;
+			return -EIO;
+		}
+		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");
+				folio_release_kmap(folio, kaddr);
+				return -EIO;
+			}
+			if (de->inode) {
+				unsigned char t;
+
+				t = fs_ftype_to_dtype(de->file_type);
+
+				if (!dir_emit(ctx, de->name, de->name_len,
+						le64_to_cpu(de->inode), t)) {
+					folio_release_kmap(folio, kaddr);
+					return 0;
+				}
+			}
+			ctx->pos += nilfs_rec_len_from_disk(de->rec_len);
+		}
+		folio_release_kmap(folio, kaddr);
+	}
+	return 0;
+}
+
+/*
+ * nilfs_find_entry()
+ *
+ * Finds an entry in the specified directory with the wanted name. It
+ * returns the folio in which the entry was found, and the entry itself.
+ * The folio is mapped and unlocked.  When the caller is finished with
+ * the entry, it should call folio_release_kmap().
+ *
+ * On failure, returns an error pointer and the caller should ignore foliop.
+ */
+struct nilfs_dir_entry *nilfs_find_entry(struct inode *dir,
+		const struct qstr *qstr, struct folio **foliop)
+{
+	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 nilfs_inode_info *ei = NILFS_I(dir);
+	struct nilfs_dir_entry *de;
+
+	if (npages == 0)
+		goto out;
+
+	start = ei->i_dir_start_lookup;
+	if (start >= npages)
+		start = 0;
+	n = start;
+	do {
+		char *kaddr = nilfs_get_folio(dir, n, foliop);
+
+		if (IS_ERR(kaddr))
+			return ERR_CAST(kaddr);
+
+		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");
+				folio_release_kmap(*foliop, kaddr);
+				goto out;
+			}
+			if (nilfs_match(namelen, name, de))
+				goto found;
+			de = nilfs_next_entry(de);
+		}
+		folio_release_kmap(*foliop, kaddr);
+
+		if (++n >= npages)
+			n = 0;
+		/* next folio is past the blocks we've got */
+		if (unlikely(n > (dir->i_blocks >> (PAGE_SHIFT - 9)))) {
+			nilfs_error(dir->i_sb,
+			       "dir %llu 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 ERR_PTR(-ENOENT);
+
+found:
+	ei->i_dir_start_lookup = n;
+	return de;
+}
+
+struct nilfs_dir_entry *nilfs_dotdot(struct inode *dir, struct folio **foliop)
+{
+	struct folio *folio;
+	struct nilfs_dir_entry *de, *next_de;
+	size_t limit;
+	char *msg;
+
+	de = nilfs_get_folio(dir, 0, &folio);
+	if (IS_ERR(de))
+		return NULL;
+
+	limit = nilfs_last_byte(dir, 0);  /* is a multiple of chunk size */
+	if (unlikely(!limit || le64_to_cpu(de->inode) != dir->i_ino ||
+		     !nilfs_match(1, ".", de))) {
+		msg = "missing '.'";
+		goto fail;
+	}
+
+	next_de = nilfs_next_entry(de);
+	/*
+	 * If "next_de" has not reached the end of the chunk, there is
+	 * at least one more record.  Check whether it matches "..".
+	 */
+	if (unlikely((char *)next_de == (char *)de + nilfs_chunk_size(dir) ||
+		     !nilfs_match(2, "..", next_de))) {
+		msg = "missing '..'";
+		goto fail;
+	}
+	*foliop = folio;
+	return next_de;
+
+fail:
+	nilfs_error(dir->i_sb, "directory #%llu %s", dir->i_ino, msg);
+	folio_release_kmap(folio, de);
+	return NULL;
+}
+
+int nilfs_inode_by_name(struct inode *dir, const struct qstr *qstr, u64 *ino)
+{
+	struct nilfs_dir_entry *de;
+	struct folio *folio;
+
+	de = nilfs_find_entry(dir, qstr, &folio);
+	if (IS_ERR(de))
+		return PTR_ERR(de);
+
+	*ino = le64_to_cpu(de->inode);
+	folio_release_kmap(folio, de);
+	return 0;
+}
+
+int nilfs_set_link(struct inode *dir, struct nilfs_dir_entry *de,
+		    struct folio *folio, struct inode *inode)
+{
+	size_t from = offset_in_folio(folio, de);
+	size_t to = from + nilfs_rec_len_from_disk(de->rec_len);
+	struct address_space *mapping = folio->mapping;
+	int err;
+
+	folio_lock(folio);
+	err = nilfs_prepare_chunk(folio, from, to);
+	if (unlikely(err)) {
+		folio_unlock(folio);
+		return err;
+	}
+	de->inode = cpu_to_le64(inode->i_ino);
+	de->file_type = fs_umode_to_ftype(inode->i_mode);
+	nilfs_commit_chunk(folio, mapping, from, to);
+	inode_set_mtime_to_ts(dir, inode_set_ctime_current(dir));
+	return 0;
+}
+
+/*
+ *	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 folio *folio = NULL;
+	struct nilfs_dir_entry *de;
+	unsigned long npages = dir_pages(dir);
+	unsigned long n;
+	size_t from, to;
+	int err;
+
+	/*
+	 * We take care of directory expansion in the same loop.
+	 * This code plays outside i_size, so it locks the folio
+	 * to protect that region.
+	 */
+	for (n = 0; n <= npages; n++) {
+		char *kaddr = nilfs_get_folio(dir, n, &folio);
+		char *dir_end;
+
+		if (IS_ERR(kaddr))
+			return PTR_ERR(kaddr);
+		folio_lock(folio);
+		dir_end = kaddr + nilfs_last_byte(dir, n);
+		de = (struct nilfs_dir_entry *)kaddr;
+		kaddr += folio_size(folio) - 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);
+		}
+		folio_unlock(folio);
+		folio_release_kmap(folio, kaddr);
+	}
+	BUG();
+	return -EINVAL;
+
+got_it:
+	from = offset_in_folio(folio, de);
+	to = from + rec_len;
+	err = nilfs_prepare_chunk(folio, 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);
+	de->file_type = fs_umode_to_ftype(inode->i_mode);
+	nilfs_commit_chunk(folio, folio->mapping, from, to);
+	inode_set_mtime_to_ts(dir, inode_set_ctime_current(dir));
+	nilfs_mark_inode_dirty(dir);
+	/* OFFSET_CACHE */
+out_put:
+	folio_release_kmap(folio, de);
+	return err;
+out_unlock:
+	folio_unlock(folio);
+	goto out_put;
+}
+
+/*
+ * nilfs_delete_entry deletes a directory entry by merging it with the
+ * previous entry. Folio is up-to-date.
+ */
+int nilfs_delete_entry(struct nilfs_dir_entry *dir, struct folio *folio)
+{
+	struct address_space *mapping = folio->mapping;
+	struct inode *inode = mapping->host;
+	char *kaddr = (char *)((unsigned long)dir & ~(folio_size(folio) - 1));
+	size_t 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 - kaddr;
+	folio_lock(folio);
+	err = nilfs_prepare_chunk(folio, from, to);
+	if (unlikely(err)) {
+		folio_unlock(folio);
+		goto out;
+	}
+	if (pde)
+		pde->rec_len = nilfs_rec_len_to_disk(to - from);
+	dir->inode = 0;
+	nilfs_commit_chunk(folio, mapping, from, to);
+	inode_set_mtime_to_ts(inode, inode_set_ctime_current(inode));
+out:
+	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 folio *folio = filemap_grab_folio(mapping, 0);
+	unsigned int chunk_size = nilfs_chunk_size(inode);
+	struct nilfs_dir_entry *de;
+	int err;
+	void *kaddr;
+
+	if (IS_ERR(folio))
+		return PTR_ERR(folio);
+
+	err = nilfs_prepare_chunk(folio, 0, chunk_size);
+	if (unlikely(err)) {
+		folio_unlock(folio);
+		goto fail;
+	}
+	kaddr = kmap_local_folio(folio, 0);
+	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);
+	de->file_type = fs_umode_to_ftype(inode->i_mode);
+
+	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);
+	de->file_type = fs_umode_to_ftype(inode->i_mode);
+	kunmap_local(kaddr);
+	nilfs_commit_chunk(folio, mapping, 0, chunk_size);
+fail:
+	folio_put(folio);
+	return err;
+}
+
+/*
+ * routine to check that the specified directory is empty (for rmdir)
+ */
+int nilfs_empty_dir(struct inode *inode)
+{
+	struct folio *folio = NULL;
+	char *kaddr;
+	unsigned long i, npages = dir_pages(inode);
+
+	for (i = 0; i < npages; i++) {
+		struct nilfs_dir_entry *de;
+
+		kaddr = nilfs_get_folio(inode, i, &folio);
+		if (IS_ERR(kaddr))
+			return 0;
+
+		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);
+		}
+		folio_release_kmap(folio, kaddr);
+	}
+	return 1;
+
+not_empty:
+	folio_release_kmap(folio, kaddr);
+	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,
+	.setlease	= generic_setlease,
+};