fs/ext2/namei.c - kernel/msm - Gitiles

 /*
  * linux/fs/ext2/namei.c
  *
  * Rewrite to pagecache. Almost all code had been changed, so blame me
  * if the things go wrong. Please, send bug reports to
  * viro@parcelfarce.linux.theplanet.co.uk
  *
  * Stuff here is basically a glue between the VFS and generic UNIXish
  * filesystem that keeps everything in pagecache. All knowledge of the
  * directory layout is in fs/ext2/dir.c - it turned out to be easily separatable
  * and it's easier to debug that way. In principle we might want to
  * generalize that a bit and turn it into a library. Or not.
  *
  * The only non-static object here is ext2_dir_inode_operations.
  *
  * TODO: get rid of kmap() use, add readahead.
  *
  * 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 "ext2.h"
 #include "xattr.h"
 #include "acl.h"
 #include "xip.h"

 static inline int ext2_add_nondir(struct dentry *dentry, struct inode *inode)
 {
 	int err = ext2_add_link(dentry, inode);
 	if (!err) {
 		d_instantiate(dentry, inode);
 		return 0;
 	}
 	inode_dec_link_count(inode);
 	iput(inode);
 	return err;
 }

 /*
  * Methods themselves.
  */

 static struct dentry *ext2_lookup(struct inode * dir, struct dentry *dentry, struct nameidata *nd)
 {
 	struct inode * inode;
 	ino_t ino;

 	if (dentry->d_name.len > EXT2_NAME_LEN)
 		return ERR_PTR(-ENAMETOOLONG);

 	ino = ext2_inode_by_name(dir, dentry);
 	inode = NULL;
 	if (ino) {
 		inode = ext2_iget(dir->i_sb, ino);
 		if (IS_ERR(inode))
 			return ERR_CAST(inode);
 	}
 	return d_splice_alias(inode, dentry);
 }

 struct dentry *ext2_get_parent(struct dentry *child)
 {
 	unsigned long ino;
 	struct dentry dotdot;

 	dotdot.d_name.name = "..";
 	dotdot.d_name.len = 2;

 	ino = ext2_inode_by_name(child->d_inode, &dotdot);
 	if (!ino)
 		return ERR_PTR(-ENOENT);
 	return d_obtain_alias(ext2_iget(child->d_inode->i_sb, ino));
 }

 /*
  * 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 ext2_create (struct inode * dir, struct dentry * dentry, int mode, struct nameidata *nd)
 {
 	struct inode * inode = ext2_new_inode (dir, mode);
 	int err = PTR_ERR(inode);
 	if (!IS_ERR(inode)) {
 		inode->i_op = &ext2_file_inode_operations;
 		if (ext2_use_xip(inode->i_sb)) {
 			inode->i_mapping->a_ops = &ext2_aops_xip;
 			inode->i_fop = &ext2_xip_file_operations;
 		} else if (test_opt(inode->i_sb, NOBH)) {
 			inode->i_mapping->a_ops = &ext2_nobh_aops;
 			inode->i_fop = &ext2_file_operations;
 		} else {
 			inode->i_mapping->a_ops = &ext2_aops;
 			inode->i_fop = &ext2_file_operations;
 		}
 		mark_inode_dirty(inode);
 		err = ext2_add_nondir(dentry, inode);
 	}
 	return err;
 }

 static int ext2_mknod (struct inode * dir, struct dentry *dentry, int mode, dev_t rdev)
 {
 	struct inode * inode;
 	int err;

 	if (!new_valid_dev(rdev))
 		return -EINVAL;

 	inode = ext2_new_inode (dir, mode);
 	err = PTR_ERR(inode);
 	if (!IS_ERR(inode)) {
 		init_special_inode(inode, inode->i_mode, rdev);
 #ifdef CONFIG_EXT2_FS_XATTR
 		inode->i_op = &ext2_special_inode_operations;
 #endif
 		mark_inode_dirty(inode);
 		err = ext2_add_nondir(dentry, inode);
 	}
 	return err;
 }

 static int ext2_symlink (struct inode * dir, struct dentry * dentry,
 	const char * symname)
 {
 	struct super_block * sb = dir->i_sb;
 	int err = -ENAMETOOLONG;
 	unsigned l = strlen(symname)+1;
 	struct inode * inode;

 	if (l > sb->s_blocksize)
 		goto out;

 	inode = ext2_new_inode (dir, S_IFLNK | S_IRWXUGO);
 	err = PTR_ERR(inode);
 	if (IS_ERR(inode))
 		goto out;

 	if (l > sizeof (EXT2_I(inode)->i_data)) {
 		/* slow symlink */
 		inode->i_op = &ext2_symlink_inode_operations;
 		if (test_opt(inode->i_sb, NOBH))
 			inode->i_mapping->a_ops = &ext2_nobh_aops;
 		else
 			inode->i_mapping->a_ops = &ext2_aops;
 		err = page_symlink(inode, symname, l);
 		if (err)
 			goto out_fail;
 	} else {
 		/* fast symlink */
 		inode->i_op = &ext2_fast_symlink_inode_operations;
 		memcpy((char*)(EXT2_I(inode)->i_data),symname,l);
 		inode->i_size = l-1;
 	}
 	mark_inode_dirty(inode);

 	err = ext2_add_nondir(dentry, inode);
 out:
 	return err;

 out_fail:
 	inode_dec_link_count(inode);
 	iput (inode);
 	goto out;
 }

 static int ext2_link (struct dentry * old_dentry, struct inode * dir,
 	struct dentry *dentry)
 {
 	struct inode *inode = old_dentry->d_inode;

 	if (inode->i_nlink >= EXT2_LINK_MAX)
 		return -EMLINK;

 	inode->i_ctime = CURRENT_TIME_SEC;
 	inode_inc_link_count(inode);
 	atomic_inc(&inode->i_count);

 	return ext2_add_nondir(dentry, inode);
 }

 static int ext2_mkdir(struct inode * dir, struct dentry * dentry, int mode)
 {
 	struct inode * inode;
 	int err = -EMLINK;

 	if (dir->i_nlink >= EXT2_LINK_MAX)
 		goto out;

 	inode_inc_link_count(dir);

 	inode = ext2_new_inode (dir, S_IFDIR | mode);
 	err = PTR_ERR(inode);
 	if (IS_ERR(inode))
 		goto out_dir;

 	inode->i_op = &ext2_dir_inode_operations;
 	inode->i_fop = &ext2_dir_operations;
 	if (test_opt(inode->i_sb, NOBH))
 		inode->i_mapping->a_ops = &ext2_nobh_aops;
 	else
 		inode->i_mapping->a_ops = &ext2_aops;

 	inode_inc_link_count(inode);

 	err = ext2_make_empty(inode, dir);
 	if (err)
 		goto out_fail;

 	err = ext2_add_link(dentry, inode);
 	if (err)
 		goto out_fail;

 	d_instantiate(dentry, inode);
 out:
 	return err;

 out_fail:
 	inode_dec_link_count(inode);
 	inode_dec_link_count(inode);
 	iput(inode);
 out_dir:
 	inode_dec_link_count(dir);
 	goto out;
 }

 static int ext2_unlink(struct inode * dir, struct dentry *dentry)
 {
 	struct inode * inode = dentry->d_inode;
 	struct ext2_dir_entry_2 * de;
 	struct page * page;
 	int err = -ENOENT;

 	de = ext2_find_entry (dir, dentry, &page);
 	if (!de)
 		goto out;

 	err = ext2_delete_entry (de, page);
 	if (err)
 		goto out;

 	inode->i_ctime = dir->i_ctime;
 	inode_dec_link_count(inode);
 	err = 0;
 out:
 	return err;
 }

 static int ext2_rmdir (struct inode * dir, struct dentry *dentry)
 {
 	struct inode * inode = dentry->d_inode;
 	int err = -ENOTEMPTY;

 	if (ext2_empty_dir(inode)) {
 		err = ext2_unlink(dir, dentry);
 		if (!err) {
 			inode->i_size = 0;
 			inode_dec_link_count(inode);
 			inode_dec_link_count(dir);
 		}
 	}
 	return err;
 }

 static int ext2_rename (struct inode * old_dir, struct dentry * old_dentry,
 	struct inode * new_dir,	struct dentry * new_dentry )
 {
 	struct inode * old_inode = old_dentry->d_inode;
 	struct inode * new_inode = new_dentry->d_inode;
 	struct page * dir_page = NULL;
 	struct ext2_dir_entry_2 * dir_de = NULL;
 	struct page * old_page;
 	struct ext2_dir_entry_2 * old_de;
 	int err = -ENOENT;

 	old_de = ext2_find_entry (old_dir, old_dentry, &old_page);
 	if (!old_de)
 		goto out;

 	if (S_ISDIR(old_inode->i_mode)) {
 		err = -EIO;
 		dir_de = ext2_dotdot(old_inode, &dir_page);
 		if (!dir_de)
 			goto out_old;
 	}

 	if (new_inode) {
 		struct page *new_page;
 		struct ext2_dir_entry_2 *new_de;

 		err = -ENOTEMPTY;
 		if (dir_de && !ext2_empty_dir (new_inode))
 			goto out_dir;

 		err = -ENOENT;
 		new_de = ext2_find_entry (new_dir, new_dentry, &new_page);
 		if (!new_de)
 			goto out_dir;
 		inode_inc_link_count(old_inode);
 		ext2_set_link(new_dir, new_de, new_page, old_inode);
 		new_inode->i_ctime = CURRENT_TIME_SEC;
 		if (dir_de)
 			drop_nlink(new_inode);
 		inode_dec_link_count(new_inode);
 	} else {
 		if (dir_de) {
 			err = -EMLINK;
 			if (new_dir->i_nlink >= EXT2_LINK_MAX)
 				goto out_dir;
 		}
 		inode_inc_link_count(old_inode);
 		err = ext2_add_link(new_dentry, old_inode);
 		if (err) {
 			inode_dec_link_count(old_inode);
 			goto out_dir;
 		}
 		if (dir_de)
 			inode_inc_link_count(new_dir);
 	}

 	/*
 	 * Like most other Unix systems, set the ctime for inodes on a
  	 * rename.
 	 * inode_dec_link_count() will mark the inode dirty.
 	 */
 	old_inode->i_ctime = CURRENT_TIME_SEC;

 	ext2_delete_entry (old_de, old_page);
 	inode_dec_link_count(old_inode);

 	if (dir_de) {
 		ext2_set_link(old_inode, dir_de, dir_page, new_dir);
 		inode_dec_link_count(old_dir);
 	}
 	return 0;


 out_dir:
 	if (dir_de) {
 		kunmap(dir_page);
 		page_cache_release(dir_page);
 	}
 out_old:
 	kunmap(old_page);
 	page_cache_release(old_page);
 out:
 	return err;
 }

 const struct inode_operations ext2_dir_inode_operations = {
 	.create		= ext2_create,
 	.lookup		= ext2_lookup,
 	.link		= ext2_link,
 	.unlink		= ext2_unlink,
 	.symlink	= ext2_symlink,
 	.mkdir		= ext2_mkdir,
 	.rmdir		= ext2_rmdir,
 	.mknod		= ext2_mknod,
 	.rename		= ext2_rename,
 #ifdef CONFIG_EXT2_FS_XATTR
 	.setxattr	= generic_setxattr,
 	.getxattr	= generic_getxattr,
 	.listxattr	= ext2_listxattr,
 	.removexattr	= generic_removexattr,
 #endif
 	.setattr	= ext2_setattr,
 	.permission	= ext2_permission,
 };

 const struct inode_operations ext2_special_inode_operations = {
 #ifdef CONFIG_EXT2_FS_XATTR
 	.setxattr	= generic_setxattr,
 	.getxattr	= generic_getxattr,
 	.listxattr	= ext2_listxattr,
 	.removexattr	= generic_removexattr,
 #endif
 	.setattr	= ext2_setattr,
 	.permission	= ext2_permission,
 };
	/*
	* linux/fs/ext2/namei.c
	*
	* Rewrite to pagecache. Almost all code had been changed, so blame me
	* if the things go wrong. Please, send bug reports to
	* viro@parcelfarce.linux.theplanet.co.uk
	*
	* Stuff here is basically a glue between the VFS and generic UNIXish
	* filesystem that keeps everything in pagecache. All knowledge of the
	* directory layout is in fs/ext2/dir.c - it turned out to be easily separatable
	* and it's easier to debug that way. In principle we might want to
	* generalize that a bit and turn it into a library. Or not.
	*
	* The only non-static object here is ext2_dir_inode_operations.
	*
	* TODO: get rid of kmap() use, add readahead.
	*
	* 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 "ext2.h"
	#include "xattr.h"
	#include "acl.h"
	#include "xip.h"

	static inline int ext2_add_nondir(struct dentry dentry, struct inode inode)
	{
	int err = ext2_add_link(dentry, inode);
	if (!err) {
	d_instantiate(dentry, inode);
	return 0;
	}
	inode_dec_link_count(inode);
	iput(inode);
	return err;
	}

	/*
	* Methods themselves.
	*/

	static struct dentry ext2_lookup(struct inode dir, struct dentry dentry, struct nameidata nd)
	{
	struct inode * inode;
	ino_t ino;

	if (dentry->d_name.len > EXT2_NAME_LEN)
	return ERR_PTR(-ENAMETOOLONG);

	ino = ext2_inode_by_name(dir, dentry);
	inode = NULL;
	if (ino) {
	inode = ext2_iget(dir->i_sb, ino);
	if (IS_ERR(inode))
	return ERR_CAST(inode);
	}
	return d_splice_alias(inode, dentry);
	}

	struct dentry ext2_get_parent(struct dentry child)
	{
	unsigned long ino;
	struct dentry dotdot;

	dotdot.d_name.name = "..";
	dotdot.d_name.len = 2;

	ino = ext2_inode_by_name(child->d_inode, &dotdot);
	if (!ino)
	return ERR_PTR(-ENOENT);
	return d_obtain_alias(ext2_iget(child->d_inode->i_sb, ino));
	}

	/*
	* 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 ext2_create (struct inode * dir, struct dentry * dentry, int mode, struct nameidata *nd)
	{
	struct inode * inode = ext2_new_inode (dir, mode);
	int err = PTR_ERR(inode);
	if (!IS_ERR(inode)) {
	inode->i_op = &ext2_file_inode_operations;
	if (ext2_use_xip(inode->i_sb)) {
	inode->i_mapping->a_ops = &ext2_aops_xip;
	inode->i_fop = &ext2_xip_file_operations;
	} else if (test_opt(inode->i_sb, NOBH)) {
	inode->i_mapping->a_ops = &ext2_nobh_aops;
	inode->i_fop = &ext2_file_operations;
	} else {
	inode->i_mapping->a_ops = &ext2_aops;
	inode->i_fop = &ext2_file_operations;
	}
	mark_inode_dirty(inode);
	err = ext2_add_nondir(dentry, inode);
	}
	return err;
	}

	static int ext2_mknod (struct inode * dir, struct dentry *dentry, int mode, dev_t rdev)
	{
	struct inode * inode;
	int err;

	if (!new_valid_dev(rdev))
	return -EINVAL;

	inode = ext2_new_inode (dir, mode);
	err = PTR_ERR(inode);
	if (!IS_ERR(inode)) {
	init_special_inode(inode, inode->i_mode, rdev);
	#ifdef CONFIG_EXT2_FS_XATTR
	inode->i_op = &ext2_special_inode_operations;
	#endif
	mark_inode_dirty(inode);
	err = ext2_add_nondir(dentry, inode);
	}
	return err;
	}

	static int ext2_symlink (struct inode * dir, struct dentry * dentry,
	const char * symname)
	{
	struct super_block * sb = dir->i_sb;
	int err = -ENAMETOOLONG;
	unsigned l = strlen(symname)+1;
	struct inode * inode;

	if (l > sb->s_blocksize)
	goto out;

	inode = ext2_new_inode (dir, S_IFLNK \| S_IRWXUGO);
	err = PTR_ERR(inode);
	if (IS_ERR(inode))
	goto out;

	if (l > sizeof (EXT2_I(inode)->i_data)) {
	/* slow symlink */
	inode->i_op = &ext2_symlink_inode_operations;
	if (test_opt(inode->i_sb, NOBH))
	inode->i_mapping->a_ops = &ext2_nobh_aops;
	else
	inode->i_mapping->a_ops = &ext2_aops;
	err = page_symlink(inode, symname, l);
	if (err)
	goto out_fail;
	} else {
	/* fast symlink */
	inode->i_op = &ext2_fast_symlink_inode_operations;
	memcpy((char*)(EXT2_I(inode)->i_data),symname,l);
	inode->i_size = l-1;
	}
	mark_inode_dirty(inode);

	err = ext2_add_nondir(dentry, inode);
	out:
	return err;

	out_fail:
	inode_dec_link_count(inode);
	iput (inode);
	goto out;
	}

	static int ext2_link (struct dentry * old_dentry, struct inode * dir,
	struct dentry *dentry)
	{
	struct inode *inode = old_dentry->d_inode;

	if (inode->i_nlink >= EXT2_LINK_MAX)
	return -EMLINK;

	inode->i_ctime = CURRENT_TIME_SEC;
	inode_inc_link_count(inode);
	atomic_inc(&inode->i_count);

	return ext2_add_nondir(dentry, inode);
	}

	static int ext2_mkdir(struct inode * dir, struct dentry * dentry, int mode)
	{
	struct inode * inode;
	int err = -EMLINK;

	if (dir->i_nlink >= EXT2_LINK_MAX)
	goto out;

	inode_inc_link_count(dir);

	inode = ext2_new_inode (dir, S_IFDIR \| mode);
	err = PTR_ERR(inode);
	if (IS_ERR(inode))
	goto out_dir;

	inode->i_op = &ext2_dir_inode_operations;
	inode->i_fop = &ext2_dir_operations;
	if (test_opt(inode->i_sb, NOBH))
	inode->i_mapping->a_ops = &ext2_nobh_aops;
	else
	inode->i_mapping->a_ops = &ext2_aops;

	inode_inc_link_count(inode);

	err = ext2_make_empty(inode, dir);
	if (err)
	goto out_fail;

	err = ext2_add_link(dentry, inode);
	if (err)
	goto out_fail;

	d_instantiate(dentry, inode);
	out:
	return err;

	out_fail:
	inode_dec_link_count(inode);
	inode_dec_link_count(inode);
	iput(inode);
	out_dir:
	inode_dec_link_count(dir);
	goto out;
	}

	static int ext2_unlink(struct inode * dir, struct dentry *dentry)
	{
	struct inode * inode = dentry->d_inode;
	struct ext2_dir_entry_2 * de;
	struct page * page;
	int err = -ENOENT;

	de = ext2_find_entry (dir, dentry, &page);
	if (!de)
	goto out;

	err = ext2_delete_entry (de, page);
	if (err)
	goto out;

	inode->i_ctime = dir->i_ctime;
	inode_dec_link_count(inode);
	err = 0;
	out:
	return err;
	}

	static int ext2_rmdir (struct inode * dir, struct dentry *dentry)
	{
	struct inode * inode = dentry->d_inode;
	int err = -ENOTEMPTY;

	if (ext2_empty_dir(inode)) {
	err = ext2_unlink(dir, dentry);
	if (!err) {
	inode->i_size = 0;
	inode_dec_link_count(inode);
	inode_dec_link_count(dir);
	}
	}
	return err;
	}

	static int ext2_rename (struct inode * old_dir, struct dentry * old_dentry,
	struct inode * new_dir, struct dentry * new_dentry )
	{
	struct inode * old_inode = old_dentry->d_inode;
	struct inode * new_inode = new_dentry->d_inode;
	struct page * dir_page = NULL;
	struct ext2_dir_entry_2 * dir_de = NULL;
	struct page * old_page;
	struct ext2_dir_entry_2 * old_de;
	int err = -ENOENT;

	old_de = ext2_find_entry (old_dir, old_dentry, &old_page);
	if (!old_de)
	goto out;

	if (S_ISDIR(old_inode->i_mode)) {
	err = -EIO;
	dir_de = ext2_dotdot(old_inode, &dir_page);
	if (!dir_de)
	goto out_old;
	}

	if (new_inode) {
	struct page *new_page;
	struct ext2_dir_entry_2 *new_de;

	err = -ENOTEMPTY;
	if (dir_de && !ext2_empty_dir (new_inode))
	goto out_dir;

	err = -ENOENT;
	new_de = ext2_find_entry (new_dir, new_dentry, &new_page);
	if (!new_de)
	goto out_dir;
	inode_inc_link_count(old_inode);
	ext2_set_link(new_dir, new_de, new_page, old_inode);
	new_inode->i_ctime = CURRENT_TIME_SEC;
	if (dir_de)
	drop_nlink(new_inode);
	inode_dec_link_count(new_inode);
	} else {
	if (dir_de) {
	err = -EMLINK;
	if (new_dir->i_nlink >= EXT2_LINK_MAX)
	goto out_dir;
	}
	inode_inc_link_count(old_inode);
	err = ext2_add_link(new_dentry, old_inode);
	if (err) {
	inode_dec_link_count(old_inode);
	goto out_dir;
	}
	if (dir_de)
	inode_inc_link_count(new_dir);
	}

	/*
	* Like most other Unix systems, set the ctime for inodes on a
	* rename.
	* inode_dec_link_count() will mark the inode dirty.
	*/
	old_inode->i_ctime = CURRENT_TIME_SEC;

	ext2_delete_entry (old_de, old_page);
	inode_dec_link_count(old_inode);

	if (dir_de) {
	ext2_set_link(old_inode, dir_de, dir_page, new_dir);
	inode_dec_link_count(old_dir);
	}
	return 0;


	out_dir:
	if (dir_de) {
	kunmap(dir_page);
	page_cache_release(dir_page);
	}
	out_old:
	kunmap(old_page);
	page_cache_release(old_page);
	out:
	return err;
	}

	const struct inode_operations ext2_dir_inode_operations = {
	.create = ext2_create,
	.lookup = ext2_lookup,
	.link = ext2_link,
	.unlink = ext2_unlink,
	.symlink = ext2_symlink,
	.mkdir = ext2_mkdir,
	.rmdir = ext2_rmdir,
	.mknod = ext2_mknod,
	.rename = ext2_rename,
	#ifdef CONFIG_EXT2_FS_XATTR
	.setxattr = generic_setxattr,
	.getxattr = generic_getxattr,
	.listxattr = ext2_listxattr,
	.removexattr = generic_removexattr,
	#endif
	.setattr = ext2_setattr,
	.permission = ext2_permission,
	};

	const struct inode_operations ext2_special_inode_operations = {
	#ifdef CONFIG_EXT2_FS_XATTR
	.setxattr = generic_setxattr,
	.getxattr = generic_getxattr,
	.listxattr = ext2_listxattr,
	.removexattr = generic_removexattr,
	#endif
	.setattr = ext2_setattr,
	.permission = ext2_permission,
	};