fs/nilfs2/namei.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0+
 /*
  * NILFS pathname lookup operations.
  *
  * Copyright (C) 2005-2008 Nippon Telegraph and Telephone Corporation.
  *
  * Modified for NILFS by Amagai Yoshiji and Ryusuke Konishi.
  */
 /*
  *  linux/fs/ext2/namei.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/namei.c
  *
  *  Copyright (C) 1991, 1992  Linus Torvalds
  *
  *  Big-endian to little-endian byte-swapping/bitmaps by
  *        David S. Miller (davem@caip.rutgers.edu), 1995
  */

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

 #define NILFS_FID_SIZE_NON_CONNECTABLE \
 	(offsetof(struct nilfs_fid, parent_gen) / 4)
 #define NILFS_FID_SIZE_CONNECTABLE	(sizeof(struct nilfs_fid) / 4)

 static inline int nilfs_add_nondir(struct dentry *dentry, struct inode *inode)
 {
 	int err = nilfs_add_link(dentry, inode);

 	if (!err) {
 		d_instantiate_new(dentry, inode);
 		return 0;
 	}
 	inode_dec_link_count(inode);
 	unlock_new_inode(inode);
 	iput(inode);
 	return err;
 }

 /*
  * Methods themselves.
  */

 static struct dentry *
 nilfs_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags)
 {
 	struct inode *inode;
 	ino_t ino;
 	int res;

 	if (dentry->d_name.len > NILFS_NAME_LEN)
 		return ERR_PTR(-ENAMETOOLONG);

 	res = nilfs_inode_by_name(dir, &dentry->d_name, &ino);
 	if (res) {
 		if (res != -ENOENT)
 			return ERR_PTR(res);
 		inode = NULL;
 	} else {
 		inode = nilfs_iget(dir->i_sb, NILFS_I(dir)->i_root, ino);
 	}

 	return d_splice_alias(inode, dentry);
 }

 /*
  * By the time this is called, we already have created
  * the directory cache entry for the new file, but it
  * is so far negative - it has no inode.
  *
  * If the create succeeds, we fill in the inode information
  * with d_instantiate().
  */
 static int nilfs_create(struct mnt_idmap *idmap, struct inode *dir,
 			struct dentry *dentry, umode_t mode, bool excl)
 {
 	struct inode *inode;
 	struct nilfs_transaction_info ti;
 	int err;

 	err = nilfs_transaction_begin(dir->i_sb, &ti, 1);
 	if (err)
 		return err;
 	inode = nilfs_new_inode(dir, mode);
 	err = PTR_ERR(inode);
 	if (!IS_ERR(inode)) {
 		inode->i_op = &nilfs_file_inode_operations;
 		inode->i_fop = &nilfs_file_operations;
 		inode->i_mapping->a_ops = &nilfs_aops;
 		nilfs_mark_inode_dirty(inode);
 		err = nilfs_add_nondir(dentry, inode);
 	}
 	if (!err)
 		err = nilfs_transaction_commit(dir->i_sb);
 	else
 		nilfs_transaction_abort(dir->i_sb);

 	return err;
 }

 static int
 nilfs_mknod(struct mnt_idmap *idmap, struct inode *dir,
 	    struct dentry *dentry, umode_t mode, dev_t rdev)
 {
 	struct inode *inode;
 	struct nilfs_transaction_info ti;
 	int err;

 	err = nilfs_transaction_begin(dir->i_sb, &ti, 1);
 	if (err)
 		return err;
 	inode = nilfs_new_inode(dir, mode);
 	err = PTR_ERR(inode);
 	if (!IS_ERR(inode)) {
 		init_special_inode(inode, inode->i_mode, rdev);
 		nilfs_mark_inode_dirty(inode);
 		err = nilfs_add_nondir(dentry, inode);
 	}
 	if (!err)
 		err = nilfs_transaction_commit(dir->i_sb);
 	else
 		nilfs_transaction_abort(dir->i_sb);

 	return err;
 }

 static int nilfs_symlink(struct mnt_idmap *idmap, struct inode *dir,
 			 struct dentry *dentry, const char *symname)
 {
 	struct nilfs_transaction_info ti;
 	struct super_block *sb = dir->i_sb;
 	unsigned int l = strlen(symname) + 1;
 	struct inode *inode;
 	int err;

 	if (l > sb->s_blocksize)
 		return -ENAMETOOLONG;

 	err = nilfs_transaction_begin(dir->i_sb, &ti, 1);
 	if (err)
 		return err;

 	inode = nilfs_new_inode(dir, S_IFLNK | 0777);
 	err = PTR_ERR(inode);
 	if (IS_ERR(inode))
 		goto out;

 	/* slow symlink */
 	inode->i_op = &nilfs_symlink_inode_operations;
 	inode_nohighmem(inode);
 	mapping_set_gfp_mask(inode->i_mapping,
 			     mapping_gfp_constraint(inode->i_mapping,
 						    ~__GFP_FS));
 	inode->i_mapping->a_ops = &nilfs_aops;
 	err = page_symlink(inode, symname, l);
 	if (err)
 		goto out_fail;

 	/* mark_inode_dirty(inode); */
 	/* page_symlink() do this */

 	err = nilfs_add_nondir(dentry, inode);
 out:
 	if (!err)
 		err = nilfs_transaction_commit(dir->i_sb);
 	else
 		nilfs_transaction_abort(dir->i_sb);

 	return err;

 out_fail:
 	drop_nlink(inode);
 	nilfs_mark_inode_dirty(inode);
 	unlock_new_inode(inode);
 	iput(inode);
 	goto out;
 }

 static int nilfs_link(struct dentry *old_dentry, struct inode *dir,
 		      struct dentry *dentry)
 {
 	struct inode *inode = d_inode(old_dentry);
 	struct nilfs_transaction_info ti;
 	int err;

 	err = nilfs_transaction_begin(dir->i_sb, &ti, 1);
 	if (err)
 		return err;

 	inode_set_ctime_current(inode);
 	inode_inc_link_count(inode);
 	ihold(inode);

 	err = nilfs_add_link(dentry, inode);
 	if (!err) {
 		d_instantiate(dentry, inode);
 		err = nilfs_transaction_commit(dir->i_sb);
 	} else {
 		inode_dec_link_count(inode);
 		iput(inode);
 		nilfs_transaction_abort(dir->i_sb);
 	}

 	return err;
 }

 static int nilfs_mkdir(struct mnt_idmap *idmap, struct inode *dir,
 		       struct dentry *dentry, umode_t mode)
 {
 	struct inode *inode;
 	struct nilfs_transaction_info ti;
 	int err;

 	err = nilfs_transaction_begin(dir->i_sb, &ti, 1);
 	if (err)
 		return err;

 	inc_nlink(dir);

 	inode = nilfs_new_inode(dir, S_IFDIR | mode);
 	err = PTR_ERR(inode);
 	if (IS_ERR(inode))
 		goto out_dir;

 	inode->i_op = &nilfs_dir_inode_operations;
 	inode->i_fop = &nilfs_dir_operations;
 	inode->i_mapping->a_ops = &nilfs_aops;

 	inc_nlink(inode);

 	err = nilfs_make_empty(inode, dir);
 	if (err)
 		goto out_fail;

 	err = nilfs_add_link(dentry, inode);
 	if (err)
 		goto out_fail;

 	nilfs_mark_inode_dirty(inode);
 	d_instantiate_new(dentry, inode);
 out:
 	if (!err)
 		err = nilfs_transaction_commit(dir->i_sb);
 	else
 		nilfs_transaction_abort(dir->i_sb);

 	return err;

 out_fail:
 	drop_nlink(inode);
 	drop_nlink(inode);
 	nilfs_mark_inode_dirty(inode);
 	unlock_new_inode(inode);
 	iput(inode);
 out_dir:
 	drop_nlink(dir);
 	nilfs_mark_inode_dirty(dir);
 	goto out;
 }

 static int nilfs_do_unlink(struct inode *dir, struct dentry *dentry)
 {
 	struct inode *inode;
 	struct nilfs_dir_entry *de;
 	struct folio *folio;
 	int err;

 	de = nilfs_find_entry(dir, &dentry->d_name, &folio);
 	if (IS_ERR(de)) {
 		err = PTR_ERR(de);
 		goto out;
 	}

 	inode = d_inode(dentry);
 	err = -EIO;
 	if (le64_to_cpu(de->inode) != inode->i_ino)
 		goto out;

 	if (!inode->i_nlink) {
 		nilfs_warn(inode->i_sb,
 			   "deleting nonexistent file (ino=%lu), %d",
 			   inode->i_ino, inode->i_nlink);
 		set_nlink(inode, 1);
 	}
 	err = nilfs_delete_entry(de, folio);
 	folio_release_kmap(folio, de);
 	if (err)
 		goto out;

 	inode_set_ctime_to_ts(inode, inode_get_ctime(dir));
 	drop_nlink(inode);
 	err = 0;
 out:
 	return err;
 }

 static int nilfs_unlink(struct inode *dir, struct dentry *dentry)
 {
 	struct nilfs_transaction_info ti;
 	int err;

 	err = nilfs_transaction_begin(dir->i_sb, &ti, 0);
 	if (err)
 		return err;

 	err = nilfs_do_unlink(dir, dentry);

 	if (!err) {
 		nilfs_mark_inode_dirty(dir);
 		nilfs_mark_inode_dirty(d_inode(dentry));
 		err = nilfs_transaction_commit(dir->i_sb);
 	} else
 		nilfs_transaction_abort(dir->i_sb);

 	return err;
 }

 static int nilfs_rmdir(struct inode *dir, struct dentry *dentry)
 {
 	struct inode *inode = d_inode(dentry);
 	struct nilfs_transaction_info ti;
 	int err;

 	err = nilfs_transaction_begin(dir->i_sb, &ti, 0);
 	if (err)
 		return err;

 	err = -ENOTEMPTY;
 	if (nilfs_empty_dir(inode)) {
 		err = nilfs_do_unlink(dir, dentry);
 		if (!err) {
 			inode->i_size = 0;
 			drop_nlink(inode);
 			nilfs_mark_inode_dirty(inode);
 			drop_nlink(dir);
 			nilfs_mark_inode_dirty(dir);
 		}
 	}
 	if (!err)
 		err = nilfs_transaction_commit(dir->i_sb);
 	else
 		nilfs_transaction_abort(dir->i_sb);

 	return err;
 }

 static int nilfs_rename(struct mnt_idmap *idmap,
 			struct inode *old_dir, struct dentry *old_dentry,
 			struct inode *new_dir, struct dentry *new_dentry,
 			unsigned int flags)
 {
 	struct inode *old_inode = d_inode(old_dentry);
 	struct inode *new_inode = d_inode(new_dentry);
 	struct folio *dir_folio = NULL;
 	struct nilfs_dir_entry *dir_de = NULL;
 	struct folio *old_folio;
 	struct nilfs_dir_entry *old_de;
 	struct nilfs_transaction_info ti;
 	int err;

 	if (flags & ~RENAME_NOREPLACE)
 		return -EINVAL;

 	err = nilfs_transaction_begin(old_dir->i_sb, &ti, 1);
 	if (unlikely(err))
 		return err;

 	old_de = nilfs_find_entry(old_dir, &old_dentry->d_name, &old_folio);
 	if (IS_ERR(old_de)) {
 		err = PTR_ERR(old_de);
 		goto out;
 	}

 	if (S_ISDIR(old_inode->i_mode)) {
 		err = -EIO;
 		dir_de = nilfs_dotdot(old_inode, &dir_folio);
 		if (!dir_de)
 			goto out_old;
 	}

 	if (new_inode) {
 		struct folio *new_folio;
 		struct nilfs_dir_entry *new_de;

 		err = -ENOTEMPTY;
 		if (dir_de && !nilfs_empty_dir(new_inode))
 			goto out_dir;

 		new_de = nilfs_find_entry(new_dir, &new_dentry->d_name,
 					  &new_folio);
 		if (IS_ERR(new_de)) {
 			err = PTR_ERR(new_de);
 			goto out_dir;
 		}
 		nilfs_set_link(new_dir, new_de, new_folio, old_inode);
 		folio_release_kmap(new_folio, new_de);
 		nilfs_mark_inode_dirty(new_dir);
 		inode_set_ctime_current(new_inode);
 		if (dir_de)
 			drop_nlink(new_inode);
 		drop_nlink(new_inode);
 		nilfs_mark_inode_dirty(new_inode);
 	} else {
 		err = nilfs_add_link(new_dentry, old_inode);
 		if (err)
 			goto out_dir;
 		if (dir_de) {
 			inc_nlink(new_dir);
 			nilfs_mark_inode_dirty(new_dir);
 		}
 	}

 	/*
 	 * Like most other Unix systems, set the ctime for inodes on a
 	 * rename.
 	 */
 	inode_set_ctime_current(old_inode);

 	nilfs_delete_entry(old_de, old_folio);

 	if (dir_de) {
 		nilfs_set_link(old_inode, dir_de, dir_folio, new_dir);
 		folio_release_kmap(dir_folio, dir_de);
 		drop_nlink(old_dir);
 	}
 	folio_release_kmap(old_folio, old_de);

 	nilfs_mark_inode_dirty(old_dir);
 	nilfs_mark_inode_dirty(old_inode);

 	err = nilfs_transaction_commit(old_dir->i_sb);
 	return err;

 out_dir:
 	if (dir_de)
 		folio_release_kmap(dir_folio, dir_de);
 out_old:
 	folio_release_kmap(old_folio, old_de);
 out:
 	nilfs_transaction_abort(old_dir->i_sb);
 	return err;
 }

 /*
  * Export operations
  */
 static struct dentry *nilfs_get_parent(struct dentry *child)
 {
 	ino_t ino;
 	int res;
 	struct nilfs_root *root;

 	res = nilfs_inode_by_name(d_inode(child), &dotdot_name, &ino);
 	if (res)
 		return ERR_PTR(res);

 	root = NILFS_I(d_inode(child))->i_root;

 	return d_obtain_alias(nilfs_iget(child->d_sb, root, ino));
 }

 static struct dentry *nilfs_get_dentry(struct super_block *sb, u64 cno,
 				       u64 ino, u32 gen)
 {
 	struct nilfs_root *root;
 	struct inode *inode;

 	if (ino < NILFS_FIRST_INO(sb) && ino != NILFS_ROOT_INO)
 		return ERR_PTR(-ESTALE);

 	root = nilfs_lookup_root(sb->s_fs_info, cno);
 	if (!root)
 		return ERR_PTR(-ESTALE);

 	inode = nilfs_iget(sb, root, ino);
 	nilfs_put_root(root);

 	if (IS_ERR(inode))
 		return ERR_CAST(inode);
 	if (gen && inode->i_generation != gen) {
 		iput(inode);
 		return ERR_PTR(-ESTALE);
 	}
 	return d_obtain_alias(inode);
 }

 static struct dentry *nilfs_fh_to_dentry(struct super_block *sb, struct fid *fh,
 					 int fh_len, int fh_type)
 {
 	struct nilfs_fid *fid = (struct nilfs_fid *)fh;

 	if (fh_len < NILFS_FID_SIZE_NON_CONNECTABLE ||
 	    (fh_type != FILEID_NILFS_WITH_PARENT &&
 	     fh_type != FILEID_NILFS_WITHOUT_PARENT))
 		return NULL;

 	return nilfs_get_dentry(sb, fid->cno, fid->ino, fid->gen);
 }

 static struct dentry *nilfs_fh_to_parent(struct super_block *sb, struct fid *fh,
 					 int fh_len, int fh_type)
 {
 	struct nilfs_fid *fid = (struct nilfs_fid *)fh;

 	if (fh_len < NILFS_FID_SIZE_CONNECTABLE ||
 	    fh_type != FILEID_NILFS_WITH_PARENT)
 		return NULL;

 	return nilfs_get_dentry(sb, fid->cno, fid->parent_ino, fid->parent_gen);
 }

 static int nilfs_encode_fh(struct inode *inode, __u32 *fh, int *lenp,
 			   struct inode *parent)
 {
 	struct nilfs_fid *fid = (struct nilfs_fid *)fh;
 	struct nilfs_root *root = NILFS_I(inode)->i_root;
 	int type;

 	if (parent && *lenp < NILFS_FID_SIZE_CONNECTABLE) {
 		*lenp = NILFS_FID_SIZE_CONNECTABLE;
 		return FILEID_INVALID;
 	}
 	if (*lenp < NILFS_FID_SIZE_NON_CONNECTABLE) {
 		*lenp = NILFS_FID_SIZE_NON_CONNECTABLE;
 		return FILEID_INVALID;
 	}

 	fid->cno = root->cno;
 	fid->ino = inode->i_ino;
 	fid->gen = inode->i_generation;

 	if (parent) {
 		fid->parent_ino = parent->i_ino;
 		fid->parent_gen = parent->i_generation;
 		type = FILEID_NILFS_WITH_PARENT;
 		*lenp = NILFS_FID_SIZE_CONNECTABLE;
 	} else {
 		type = FILEID_NILFS_WITHOUT_PARENT;
 		*lenp = NILFS_FID_SIZE_NON_CONNECTABLE;
 	}

 	return type;
 }

 const struct inode_operations nilfs_dir_inode_operations = {
 	.create		= nilfs_create,
 	.lookup		= nilfs_lookup,
 	.link		= nilfs_link,
 	.unlink		= nilfs_unlink,
 	.symlink	= nilfs_symlink,
 	.mkdir		= nilfs_mkdir,
 	.rmdir		= nilfs_rmdir,
 	.mknod		= nilfs_mknod,
 	.rename		= nilfs_rename,
 	.setattr	= nilfs_setattr,
 	.permission	= nilfs_permission,
 	.fiemap		= nilfs_fiemap,
 	.fileattr_get	= nilfs_fileattr_get,
 	.fileattr_set	= nilfs_fileattr_set,
 };

 const struct inode_operations nilfs_special_inode_operations = {
 	.setattr	= nilfs_setattr,
 	.permission	= nilfs_permission,
 };

 const struct inode_operations nilfs_symlink_inode_operations = {
 	.get_link	= page_get_link,
 	.permission     = nilfs_permission,
 };

 const struct export_operations nilfs_export_ops = {
 	.encode_fh = nilfs_encode_fh,
 	.fh_to_dentry = nilfs_fh_to_dentry,
 	.fh_to_parent = nilfs_fh_to_parent,
 	.get_parent = nilfs_get_parent,
 };
	// SPDX-License-Identifier: GPL-2.0+
	/*
	* NILFS pathname lookup operations.
	*
	* Copyright (C) 2005-2008 Nippon Telegraph and Telephone Corporation.
	*
	* Modified for NILFS by Amagai Yoshiji and Ryusuke Konishi.
	*/
	/*
	* linux/fs/ext2/namei.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/namei.c
	*
	* Copyright (C) 1991, 1992 Linus Torvalds
	*
	* Big-endian to little-endian byte-swapping/bitmaps by
	* David S. Miller (davem@caip.rutgers.edu), 1995
	*/

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

	#define NILFS_FID_SIZE_NON_CONNECTABLE \
	(offsetof(struct nilfs_fid, parent_gen) / 4)
	#define NILFS_FID_SIZE_CONNECTABLE (sizeof(struct nilfs_fid) / 4)

	static inline int nilfs_add_nondir(struct dentry dentry, struct inode inode)
	{
	int err = nilfs_add_link(dentry, inode);

	if (!err) {
	d_instantiate_new(dentry, inode);
	return 0;
	}
	inode_dec_link_count(inode);
	unlock_new_inode(inode);
	iput(inode);
	return err;
	}

	/*
	* Methods themselves.
	*/

	static struct dentry *
	nilfs_lookup(struct inode dir, struct dentry dentry, unsigned int flags)
	{
	struct inode *inode;
	ino_t ino;
	int res;

	if (dentry->d_name.len > NILFS_NAME_LEN)
	return ERR_PTR(-ENAMETOOLONG);

	res = nilfs_inode_by_name(dir, &dentry->d_name, &ino);
	if (res) {
	if (res != -ENOENT)
	return ERR_PTR(res);
	inode = NULL;
	} else {
	inode = nilfs_iget(dir->i_sb, NILFS_I(dir)->i_root, ino);
	}

	return d_splice_alias(inode, dentry);
	}

	/*
	* By the time this is called, we already have created
	* the directory cache entry for the new file, but it
	* is so far negative - it has no inode.
	*
	* If the create succeeds, we fill in the inode information
	* with d_instantiate().
	*/
	static int nilfs_create(struct mnt_idmap idmap, struct inode dir,
	struct dentry *dentry, umode_t mode, bool excl)
	{
	struct inode *inode;
	struct nilfs_transaction_info ti;
	int err;

	err = nilfs_transaction_begin(dir->i_sb, &ti, 1);
	if (err)
	return err;
	inode = nilfs_new_inode(dir, mode);
	err = PTR_ERR(inode);
	if (!IS_ERR(inode)) {
	inode->i_op = &nilfs_file_inode_operations;
	inode->i_fop = &nilfs_file_operations;
	inode->i_mapping->a_ops = &nilfs_aops;
	nilfs_mark_inode_dirty(inode);
	err = nilfs_add_nondir(dentry, inode);
	}
	if (!err)
	err = nilfs_transaction_commit(dir->i_sb);
	else
	nilfs_transaction_abort(dir->i_sb);

	return err;
	}

	static int
	nilfs_mknod(struct mnt_idmap idmap, struct inode dir,
	struct dentry *dentry, umode_t mode, dev_t rdev)
	{
	struct inode *inode;
	struct nilfs_transaction_info ti;
	int err;

	err = nilfs_transaction_begin(dir->i_sb, &ti, 1);
	if (err)
	return err;
	inode = nilfs_new_inode(dir, mode);
	err = PTR_ERR(inode);
	if (!IS_ERR(inode)) {
	init_special_inode(inode, inode->i_mode, rdev);
	nilfs_mark_inode_dirty(inode);
	err = nilfs_add_nondir(dentry, inode);
	}
	if (!err)
	err = nilfs_transaction_commit(dir->i_sb);
	else
	nilfs_transaction_abort(dir->i_sb);

	return err;
	}

	static int nilfs_symlink(struct mnt_idmap idmap, struct inode dir,
	struct dentry dentry, const char symname)
	{
	struct nilfs_transaction_info ti;
	struct super_block *sb = dir->i_sb;
	unsigned int l = strlen(symname) + 1;
	struct inode *inode;
	int err;

	if (l > sb->s_blocksize)
	return -ENAMETOOLONG;

	err = nilfs_transaction_begin(dir->i_sb, &ti, 1);
	if (err)
	return err;

	inode = nilfs_new_inode(dir, S_IFLNK \| 0777);
	err = PTR_ERR(inode);
	if (IS_ERR(inode))
	goto out;

	/* slow symlink */
	inode->i_op = &nilfs_symlink_inode_operations;
	inode_nohighmem(inode);
	mapping_set_gfp_mask(inode->i_mapping,
	mapping_gfp_constraint(inode->i_mapping,
	~__GFP_FS));
	inode->i_mapping->a_ops = &nilfs_aops;
	err = page_symlink(inode, symname, l);
	if (err)
	goto out_fail;

	/* mark_inode_dirty(inode); */
	/* page_symlink() do this */

	err = nilfs_add_nondir(dentry, inode);
	out:
	if (!err)
	err = nilfs_transaction_commit(dir->i_sb);
	else
	nilfs_transaction_abort(dir->i_sb);

	return err;

	out_fail:
	drop_nlink(inode);
	nilfs_mark_inode_dirty(inode);
	unlock_new_inode(inode);
	iput(inode);
	goto out;
	}

	static int nilfs_link(struct dentry old_dentry, struct inode dir,
	struct dentry *dentry)
	{
	struct inode *inode = d_inode(old_dentry);
	struct nilfs_transaction_info ti;
	int err;

	err = nilfs_transaction_begin(dir->i_sb, &ti, 1);
	if (err)
	return err;

	inode_set_ctime_current(inode);
	inode_inc_link_count(inode);
	ihold(inode);

	err = nilfs_add_link(dentry, inode);
	if (!err) {
	d_instantiate(dentry, inode);
	err = nilfs_transaction_commit(dir->i_sb);
	} else {
	inode_dec_link_count(inode);
	iput(inode);
	nilfs_transaction_abort(dir->i_sb);
	}

	return err;
	}

	static int nilfs_mkdir(struct mnt_idmap idmap, struct inode dir,
	struct dentry *dentry, umode_t mode)
	{
	struct inode *inode;
	struct nilfs_transaction_info ti;
	int err;

	err = nilfs_transaction_begin(dir->i_sb, &ti, 1);
	if (err)
	return err;

	inc_nlink(dir);

	inode = nilfs_new_inode(dir, S_IFDIR \| mode);
	err = PTR_ERR(inode);
	if (IS_ERR(inode))
	goto out_dir;

	inode->i_op = &nilfs_dir_inode_operations;
	inode->i_fop = &nilfs_dir_operations;
	inode->i_mapping->a_ops = &nilfs_aops;

	inc_nlink(inode);

	err = nilfs_make_empty(inode, dir);
	if (err)
	goto out_fail;

	err = nilfs_add_link(dentry, inode);
	if (err)
	goto out_fail;

	nilfs_mark_inode_dirty(inode);
	d_instantiate_new(dentry, inode);
	out:
	if (!err)
	err = nilfs_transaction_commit(dir->i_sb);
	else
	nilfs_transaction_abort(dir->i_sb);

	return err;

	out_fail:
	drop_nlink(inode);
	drop_nlink(inode);
	nilfs_mark_inode_dirty(inode);
	unlock_new_inode(inode);
	iput(inode);
	out_dir:
	drop_nlink(dir);
	nilfs_mark_inode_dirty(dir);
	goto out;
	}

	static int nilfs_do_unlink(struct inode dir, struct dentry dentry)
	{
	struct inode *inode;
	struct nilfs_dir_entry *de;
	struct folio *folio;
	int err;

	de = nilfs_find_entry(dir, &dentry->d_name, &folio);
	if (IS_ERR(de)) {
	err = PTR_ERR(de);
	goto out;
	}

	inode = d_inode(dentry);
	err = -EIO;
	if (le64_to_cpu(de->inode) != inode->i_ino)
	goto out;

	if (!inode->i_nlink) {
	nilfs_warn(inode->i_sb,
	"deleting nonexistent file (ino=%lu), %d",
	inode->i_ino, inode->i_nlink);
	set_nlink(inode, 1);
	}
	err = nilfs_delete_entry(de, folio);
	folio_release_kmap(folio, de);
	if (err)
	goto out;

	inode_set_ctime_to_ts(inode, inode_get_ctime(dir));
	drop_nlink(inode);
	err = 0;
	out:
	return err;
	}

	static int nilfs_unlink(struct inode dir, struct dentry dentry)
	{
	struct nilfs_transaction_info ti;
	int err;

	err = nilfs_transaction_begin(dir->i_sb, &ti, 0);
	if (err)
	return err;

	err = nilfs_do_unlink(dir, dentry);

	if (!err) {
	nilfs_mark_inode_dirty(dir);
	nilfs_mark_inode_dirty(d_inode(dentry));
	err = nilfs_transaction_commit(dir->i_sb);
	} else
	nilfs_transaction_abort(dir->i_sb);

	return err;
	}

	static int nilfs_rmdir(struct inode dir, struct dentry dentry)
	{
	struct inode *inode = d_inode(dentry);
	struct nilfs_transaction_info ti;
	int err;

	err = nilfs_transaction_begin(dir->i_sb, &ti, 0);
	if (err)
	return err;

	err = -ENOTEMPTY;
	if (nilfs_empty_dir(inode)) {
	err = nilfs_do_unlink(dir, dentry);
	if (!err) {
	inode->i_size = 0;
	drop_nlink(inode);
	nilfs_mark_inode_dirty(inode);
	drop_nlink(dir);
	nilfs_mark_inode_dirty(dir);
	}
	}
	if (!err)
	err = nilfs_transaction_commit(dir->i_sb);
	else
	nilfs_transaction_abort(dir->i_sb);

	return err;
	}

	static int nilfs_rename(struct mnt_idmap *idmap,
	struct inode old_dir, struct dentry old_dentry,
	struct inode new_dir, struct dentry new_dentry,
	unsigned int flags)
	{
	struct inode *old_inode = d_inode(old_dentry);
	struct inode *new_inode = d_inode(new_dentry);
	struct folio *dir_folio = NULL;
	struct nilfs_dir_entry *dir_de = NULL;
	struct folio *old_folio;
	struct nilfs_dir_entry *old_de;
	struct nilfs_transaction_info ti;
	int err;

	if (flags & ~RENAME_NOREPLACE)
	return -EINVAL;

	err = nilfs_transaction_begin(old_dir->i_sb, &ti, 1);
	if (unlikely(err))
	return err;

	old_de = nilfs_find_entry(old_dir, &old_dentry->d_name, &old_folio);
	if (IS_ERR(old_de)) {
	err = PTR_ERR(old_de);
	goto out;
	}

	if (S_ISDIR(old_inode->i_mode)) {
	err = -EIO;
	dir_de = nilfs_dotdot(old_inode, &dir_folio);
	if (!dir_de)
	goto out_old;
	}

	if (new_inode) {
	struct folio *new_folio;
	struct nilfs_dir_entry *new_de;

	err = -ENOTEMPTY;
	if (dir_de && !nilfs_empty_dir(new_inode))
	goto out_dir;

	new_de = nilfs_find_entry(new_dir, &new_dentry->d_name,
	&new_folio);
	if (IS_ERR(new_de)) {
	err = PTR_ERR(new_de);
	goto out_dir;
	}
	nilfs_set_link(new_dir, new_de, new_folio, old_inode);
	folio_release_kmap(new_folio, new_de);
	nilfs_mark_inode_dirty(new_dir);
	inode_set_ctime_current(new_inode);
	if (dir_de)
	drop_nlink(new_inode);
	drop_nlink(new_inode);
	nilfs_mark_inode_dirty(new_inode);
	} else {
	err = nilfs_add_link(new_dentry, old_inode);
	if (err)
	goto out_dir;
	if (dir_de) {
	inc_nlink(new_dir);
	nilfs_mark_inode_dirty(new_dir);
	}
	}

	/*
	* Like most other Unix systems, set the ctime for inodes on a
	* rename.
	*/
	inode_set_ctime_current(old_inode);

	nilfs_delete_entry(old_de, old_folio);

	if (dir_de) {
	nilfs_set_link(old_inode, dir_de, dir_folio, new_dir);
	folio_release_kmap(dir_folio, dir_de);
	drop_nlink(old_dir);
	}
	folio_release_kmap(old_folio, old_de);

	nilfs_mark_inode_dirty(old_dir);
	nilfs_mark_inode_dirty(old_inode);

	err = nilfs_transaction_commit(old_dir->i_sb);
	return err;

	out_dir:
	if (dir_de)
	folio_release_kmap(dir_folio, dir_de);
	out_old:
	folio_release_kmap(old_folio, old_de);
	out:
	nilfs_transaction_abort(old_dir->i_sb);
	return err;
	}

	/*
	* Export operations
	*/
	static struct dentry nilfs_get_parent(struct dentry child)
	{
	ino_t ino;
	int res;
	struct nilfs_root *root;

	res = nilfs_inode_by_name(d_inode(child), &dotdot_name, &ino);
	if (res)
	return ERR_PTR(res);

	root = NILFS_I(d_inode(child))->i_root;

	return d_obtain_alias(nilfs_iget(child->d_sb, root, ino));
	}

	static struct dentry nilfs_get_dentry(struct super_block sb, u64 cno,
	u64 ino, u32 gen)
	{
	struct nilfs_root *root;
	struct inode *inode;

	if (ino < NILFS_FIRST_INO(sb) && ino != NILFS_ROOT_INO)
	return ERR_PTR(-ESTALE);

	root = nilfs_lookup_root(sb->s_fs_info, cno);
	if (!root)
	return ERR_PTR(-ESTALE);

	inode = nilfs_iget(sb, root, ino);
	nilfs_put_root(root);

	if (IS_ERR(inode))
	return ERR_CAST(inode);
	if (gen && inode->i_generation != gen) {
	iput(inode);
	return ERR_PTR(-ESTALE);
	}
	return d_obtain_alias(inode);
	}

	static struct dentry nilfs_fh_to_dentry(struct super_block sb, struct fid *fh,
	int fh_len, int fh_type)
	{
	struct nilfs_fid fid = (struct nilfs_fid )fh;

	if (fh_len < NILFS_FID_SIZE_NON_CONNECTABLE \|\|
	(fh_type != FILEID_NILFS_WITH_PARENT &&
	fh_type != FILEID_NILFS_WITHOUT_PARENT))
	return NULL;

	return nilfs_get_dentry(sb, fid->cno, fid->ino, fid->gen);
	}

	static struct dentry nilfs_fh_to_parent(struct super_block sb, struct fid *fh,
	int fh_len, int fh_type)
	{
	struct nilfs_fid fid = (struct nilfs_fid )fh;

	if (fh_len < NILFS_FID_SIZE_CONNECTABLE \|\|
	fh_type != FILEID_NILFS_WITH_PARENT)
	return NULL;

	return nilfs_get_dentry(sb, fid->cno, fid->parent_ino, fid->parent_gen);
	}

	static int nilfs_encode_fh(struct inode inode, __u32 fh, int *lenp,
	struct inode *parent)
	{
	struct nilfs_fid fid = (struct nilfs_fid )fh;
	struct nilfs_root *root = NILFS_I(inode)->i_root;
	int type;

	if (parent && *lenp < NILFS_FID_SIZE_CONNECTABLE) {
	*lenp = NILFS_FID_SIZE_CONNECTABLE;
	return FILEID_INVALID;
	}
	if (*lenp < NILFS_FID_SIZE_NON_CONNECTABLE) {
	*lenp = NILFS_FID_SIZE_NON_CONNECTABLE;
	return FILEID_INVALID;
	}

	fid->cno = root->cno;
	fid->ino = inode->i_ino;
	fid->gen = inode->i_generation;

	if (parent) {
	fid->parent_ino = parent->i_ino;
	fid->parent_gen = parent->i_generation;
	type = FILEID_NILFS_WITH_PARENT;
	*lenp = NILFS_FID_SIZE_CONNECTABLE;
	} else {
	type = FILEID_NILFS_WITHOUT_PARENT;
	*lenp = NILFS_FID_SIZE_NON_CONNECTABLE;
	}

	return type;
	}

	const struct inode_operations nilfs_dir_inode_operations = {
	.create = nilfs_create,
	.lookup = nilfs_lookup,
	.link = nilfs_link,
	.unlink = nilfs_unlink,
	.symlink = nilfs_symlink,
	.mkdir = nilfs_mkdir,
	.rmdir = nilfs_rmdir,
	.mknod = nilfs_mknod,
	.rename = nilfs_rename,
	.setattr = nilfs_setattr,
	.permission = nilfs_permission,
	.fiemap = nilfs_fiemap,
	.fileattr_get = nilfs_fileattr_get,
	.fileattr_set = nilfs_fileattr_set,
	};

	const struct inode_operations nilfs_special_inode_operations = {
	.setattr = nilfs_setattr,
	.permission = nilfs_permission,
	};

	const struct inode_operations nilfs_symlink_inode_operations = {
	.get_link = page_get_link,
	.permission = nilfs_permission,
	};

	const struct export_operations nilfs_export_ops = {
	.encode_fh = nilfs_encode_fh,
	.fh_to_dentry = nilfs_fh_to_dentry,
	.fh_to_parent = nilfs_fh_to_parent,
	.get_parent = nilfs_get_parent,
	};