[mirror_ubuntu-jammy-kernel.git] / fs / overlayfs / inode.c

/*
 *
 * Copyright (C) 2011 Novell Inc.
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 as published by
 * the Free Software Foundation.
 */

#include <linux/fs.h>
#include <linux/slab.h>
#include <linux/xattr.h>
#include "overlayfs.h"

static int ovl_copy_up_truncate(struct dentry *dentry)
{
	int err;
	struct dentry *parent;
	struct kstat stat;
	struct path lowerpath;

	parent = dget_parent(dentry);
	err = ovl_copy_up(parent);
	if (err)
		goto out_dput_parent;

	ovl_path_lower(dentry, &lowerpath);
	err = vfs_getattr(&lowerpath, &stat);
	if (err)
		goto out_dput_parent;

	stat.size = 0;
	err = ovl_copy_up_one(parent, dentry, &lowerpath, &stat);

out_dput_parent:
	dput(parent);
	return err;
}

int ovl_setattr(struct dentry *dentry, struct iattr *attr)
{
	int err;
	struct dentry *upperdentry;
	const struct cred *old_cred;

	/*
	 * Check for permissions before trying to copy-up.  This is redundant
	 * since it will be rechecked later by ->setattr() on upper dentry.  But
	 * without this, copy-up can be triggered by just about anybody.
	 *
	 * We don't initialize inode->size, which just means that
	 * inode_newsize_ok() will always check against MAX_LFS_FILESIZE and not
	 * check for a swapfile (which this won't be anyway).
	 */
	err = inode_change_ok(dentry->d_inode, attr);
	if (err)
		return err;

	err = ovl_want_write(dentry);
	if (err)
		goto out;

	if (attr->ia_valid & ATTR_SIZE) {
		struct inode *realinode = d_inode(ovl_dentry_real(dentry));

		err = -ETXTBSY;
		if (atomic_read(&realinode->i_writecount) < 0)
			goto out_drop_write;
	}

	err = ovl_copy_up(dentry);
	if (!err) {
		struct inode *winode = NULL;

		upperdentry = ovl_dentry_upper(dentry);

		if (attr->ia_valid & ATTR_SIZE) {
			winode = d_inode(upperdentry);
			err = get_write_access(winode);
			if (err)
				goto out_drop_write;
		}

		if (attr->ia_valid & (ATTR_KILL_SUID|ATTR_KILL_SGID))
			attr->ia_valid &= ~ATTR_MODE;

		inode_lock(upperdentry->d_inode);
		old_cred = ovl_override_creds(dentry->d_sb);
		err = notify_change(upperdentry, attr, NULL);
		revert_creds(old_cred);
		if (!err)
			ovl_copyattr(upperdentry->d_inode, dentry->d_inode);
		inode_unlock(upperdentry->d_inode);

		if (winode)
			put_write_access(winode);
	}
out_drop_write:
	ovl_drop_write(dentry);
out:
	return err;
}

static int ovl_getattr(struct vfsmount *mnt, struct dentry *dentry,
			 struct kstat *stat)
{
	struct path realpath;
	const struct cred *old_cred;
	int err;

	ovl_path_real(dentry, &realpath);
	old_cred = ovl_override_creds(dentry->d_sb);
	err = vfs_getattr(&realpath, stat);
	revert_creds(old_cred);
	return err;
}

int ovl_permission(struct inode *inode, int mask)
{
	bool is_upper;
	struct inode *realinode = ovl_inode_real(inode, &is_upper);
	const struct cred *old_cred;
	int err;

	/* Careful in RCU walk mode */
	if (!realinode) {
		WARN_ON(!(mask & MAY_NOT_BLOCK));
		return -ECHILD;
	}

	/*
	 * Check overlay inode with the creds of task and underlying inode
	 * with creds of mounter
	 */
	err = generic_permission(inode, mask);
	if (err)
		return err;

	old_cred = ovl_override_creds(inode->i_sb);
	if (!is_upper && !special_file(realinode->i_mode) && mask & MAY_WRITE) {
		mask &= ~(MAY_WRITE | MAY_APPEND);
		/* Make sure mounter can read file for copy up later */
		mask |= MAY_READ;
	}
	err = inode_permission(realinode, mask);
	revert_creds(old_cred);

	return err;
}

static const char *ovl_get_link(struct dentry *dentry,
				struct inode *inode,
				struct delayed_call *done)
{
	struct dentry *realdentry;
	struct inode *realinode;
	const struct cred *old_cred;
	const char *p;

	if (!dentry)
		return ERR_PTR(-ECHILD);

	realdentry = ovl_dentry_real(dentry);
	realinode = realdentry->d_inode;

	if (WARN_ON(!realinode->i_op->get_link))
		return ERR_PTR(-EPERM);

	old_cred = ovl_override_creds(dentry->d_sb);
	p = realinode->i_op->get_link(realdentry, realinode, done);
	revert_creds(old_cred);
	return p;
}

static int ovl_readlink(struct dentry *dentry, char __user *buf, int bufsiz)
{
	struct path realpath;
	struct inode *realinode;
	const struct cred *old_cred;
	int err;

	ovl_path_real(dentry, &realpath);
	realinode = realpath.dentry->d_inode;

	if (!realinode->i_op->readlink)
		return -EINVAL;

	old_cred = ovl_override_creds(dentry->d_sb);
	err = realinode->i_op->readlink(realpath.dentry, buf, bufsiz);
	revert_creds(old_cred);
	return err;
}

static bool ovl_is_private_xattr(const char *name)
{
#define OVL_XATTR_PRE_NAME OVL_XATTR_PREFIX "."
	return strncmp(name, OVL_XATTR_PRE_NAME,
		       sizeof(OVL_XATTR_PRE_NAME) - 1) == 0;
}

int ovl_setxattr(struct dentry *dentry, struct inode *inode,
		 const char *name, const void *value,
		 size_t size, int flags)
{
	int err;
	struct dentry *upperdentry;
	const struct cred *old_cred;

	err = ovl_want_write(dentry);
	if (err)
		goto out;

	err = ovl_copy_up(dentry);
	if (err)
		goto out_drop_write;

	upperdentry = ovl_dentry_upper(dentry);
	old_cred = ovl_override_creds(dentry->d_sb);
	err = vfs_setxattr(upperdentry, name, value, size, flags);
	revert_creds(old_cred);

out_drop_write:
	ovl_drop_write(dentry);
out:
	return err;
}

ssize_t ovl_getxattr(struct dentry *dentry, struct inode *inode,
		     const char *name, void *value, size_t size)
{
	struct dentry *realdentry = ovl_dentry_real(dentry);
	ssize_t res;
	const struct cred *old_cred;

	if (ovl_is_private_xattr(name))
		return -ENODATA;

	old_cred = ovl_override_creds(dentry->d_sb);
	res = vfs_getxattr(realdentry, name, value, size);
	revert_creds(old_cred);
	return res;
}

ssize_t ovl_listxattr(struct dentry *dentry, char *list, size_t size)
{
	struct dentry *realdentry = ovl_dentry_real(dentry);
	ssize_t res;
	int off;
	const struct cred *old_cred;

	old_cred = ovl_override_creds(dentry->d_sb);
	res = vfs_listxattr(realdentry, list, size);
	revert_creds(old_cred);
	if (res <= 0 || size == 0)
		return res;

	/* filter out private xattrs */
	for (off = 0; off < res;) {
		char *s = list + off;
		size_t slen = strlen(s) + 1;

		BUG_ON(off + slen > res);

		if (ovl_is_private_xattr(s)) {
			res -= slen;
			memmove(s, s + slen, res - off);
		} else {
			off += slen;
		}
	}

	return res;
}

int ovl_removexattr(struct dentry *dentry, const char *name)
{
	int err;
	struct path realpath;
	enum ovl_path_type type = ovl_path_real(dentry, &realpath);
	const struct cred *old_cred;

	err = ovl_want_write(dentry);
	if (err)
		goto out;

	err = -ENODATA;
	if (ovl_is_private_xattr(name))
		goto out_drop_write;

	if (!OVL_TYPE_UPPER(type)) {
		err = vfs_getxattr(realpath.dentry, name, NULL, 0);
		if (err < 0)
			goto out_drop_write;

		err = ovl_copy_up(dentry);
		if (err)
			goto out_drop_write;

		ovl_path_upper(dentry, &realpath);
	}

	old_cred = ovl_override_creds(dentry->d_sb);
	err = vfs_removexattr(realpath.dentry, name);
	revert_creds(old_cred);
out_drop_write:
	ovl_drop_write(dentry);
out:
	return err;
}

struct posix_acl *ovl_get_acl(struct inode *inode, int type)
{
	struct inode *realinode = ovl_inode_real(inode, NULL);
	const struct cred *old_cred;
	struct posix_acl *acl;

	if (!IS_POSIXACL(realinode))
		return NULL;

	if (!realinode->i_op->get_acl)
		return NULL;

	old_cred = ovl_override_creds(inode->i_sb);
	acl = realinode->i_op->get_acl(realinode, type);
	revert_creds(old_cred);

	return acl;
}

static bool ovl_open_need_copy_up(int flags, enum ovl_path_type type,
				  struct dentry *realdentry)
{
	if (OVL_TYPE_UPPER(type))
		return false;

	if (special_file(realdentry->d_inode->i_mode))
		return false;

	if (!(OPEN_FMODE(flags) & FMODE_WRITE) && !(flags & O_TRUNC))
		return false;

	return true;
}

int ovl_open_maybe_copy_up(struct dentry *dentry, unsigned int file_flags)
{
	int err = 0;
	struct path realpath;
	enum ovl_path_type type;

	type = ovl_path_real(dentry, &realpath);
	if (ovl_open_need_copy_up(file_flags, type, realpath.dentry)) {
		err = ovl_want_write(dentry);
		if (!err) {
			if (file_flags & O_TRUNC)
				err = ovl_copy_up_truncate(dentry);
			else
				err = ovl_copy_up(dentry);
			ovl_drop_write(dentry);
		}
	}

	return err;
}

int ovl_update_time(struct inode *inode, struct timespec *ts, int flags)
{
	struct dentry *alias;
	struct path upperpath;

	if (!(flags & S_ATIME))
		return 0;

	alias = d_find_any_alias(inode);
	if (!alias)
		return 0;

	ovl_path_upper(alias, &upperpath);
	if (upperpath.dentry) {
		touch_atime(&upperpath);
		inode->i_atime = d_inode(upperpath.dentry)->i_atime;
	}

	dput(alias);

	return 0;
}

static const struct inode_operations ovl_file_inode_operations = {
	.setattr	= ovl_setattr,
	.permission	= ovl_permission,
	.getattr	= ovl_getattr,
	.setxattr	= generic_setxattr,
	.getxattr	= ovl_getxattr,
	.listxattr	= ovl_listxattr,
	.removexattr	= ovl_removexattr,
	.get_acl	= ovl_get_acl,
	.update_time	= ovl_update_time,
};

static const struct inode_operations ovl_symlink_inode_operations = {
	.setattr	= ovl_setattr,
	.get_link	= ovl_get_link,
	.readlink	= ovl_readlink,
	.getattr	= ovl_getattr,
	.setxattr	= generic_setxattr,
	.getxattr	= ovl_getxattr,
	.listxattr	= ovl_listxattr,
	.removexattr	= ovl_removexattr,
	.update_time	= ovl_update_time,
};

static void ovl_fill_inode(struct inode *inode, umode_t mode)
{
	inode->i_ino = get_next_ino();
	inode->i_mode = mode;
	inode->i_flags |= S_NOCMTIME;

	mode &= S_IFMT;
	switch (mode) {
	case S_IFDIR:
		inode->i_op = &ovl_dir_inode_operations;
		inode->i_fop = &ovl_dir_operations;
		break;

	case S_IFLNK:
		inode->i_op = &ovl_symlink_inode_operations;
		break;

	default:
		WARN(1, "illegal file type: %i\n", mode);
		/* Fall through */

	case S_IFREG:
	case S_IFSOCK:
	case S_IFBLK:
	case S_IFCHR:
	case S_IFIFO:
		inode->i_op = &ovl_file_inode_operations;
		break;
	}
}

struct inode *ovl_new_inode(struct super_block *sb, umode_t mode)
{
	struct inode *inode;

	inode = new_inode(sb);
	if (inode)
		ovl_fill_inode(inode, mode);

	return inode;
}

static int ovl_inode_test(struct inode *inode, void *data)
{
	return ovl_inode_real(inode, NULL) == data;
}

static int ovl_inode_set(struct inode *inode, void *data)
{
	inode->i_private = (void *) (((unsigned long) data) | OVL_ISUPPER_MASK);
	return 0;
}

struct inode *ovl_get_inode(struct super_block *sb, struct inode *realinode)

{
	struct inode *inode;

	inode = iget5_locked(sb, (unsigned long) realinode,
			     ovl_inode_test, ovl_inode_set, realinode);
	if (inode && inode->i_state & I_NEW) {
		ovl_fill_inode(inode, realinode->i_mode);
		set_nlink(inode, realinode->i_nlink);
		unlock_new_inode(inode);
	}

	return inode;
}
Commit	Line	Data
e9be9d5e MS	1	/*
	2	*
	3	* Copyright (C) 2011 Novell Inc.
	4	*
	5	* This program is free software; you can redistribute it and/or modify it
	6	* under the terms of the GNU General Public License version 2 as published by
	7	* the Free Software Foundation.
	8	*/
	9
	10	#include <linux/fs.h>
	11	#include <linux/slab.h>
	12	#include <linux/xattr.h>
	13	#include "overlayfs.h"
	14
0f7ff2da	15	static int ovl_copy_up_truncate(struct dentry *dentry)
e9be9d5e MS	16	{
	17	int err;
	18	struct dentry *parent;
	19	struct kstat stat;
	20	struct path lowerpath;
	21
	22	parent = dget_parent(dentry);
	23	err = ovl_copy_up(parent);
	24	if (err)
	25	goto out_dput_parent;
	26
	27	ovl_path_lower(dentry, &lowerpath);
	28	err = vfs_getattr(&lowerpath, &stat);
	29	if (err)
	30	goto out_dput_parent;
	31
0f7ff2da AV	32	stat.size = 0;
0f7ff2da AV	33	err = ovl_copy_up_one(parent, dentry, &lowerpath, &stat);
e9be9d5e MS	34
	35	out_dput_parent:
	36	dput(parent);
	37	return err;
	38	}
	39
	40	int ovl_setattr(struct dentry dentry, struct iattr attr)
	41	{
	42	int err;
	43	struct dentry *upperdentry;
1175b6b8	44	const struct cred *old_cred;
e9be9d5e	45
cf9a6784 MS	46	/*
	47	* Check for permissions before trying to copy-up. This is redundant
	48	* since it will be rechecked later by ->setattr() on upper dentry. But
	49	* without this, copy-up can be triggered by just about anybody.
	50	*
	51	* We don't initialize inode->size, which just means that
	52	* inode_newsize_ok() will always check against MAX_LFS_FILESIZE and not
	53	* check for a swapfile (which this won't be anyway).
	54	*/
	55	err = inode_change_ok(dentry->d_inode, attr);
	56	if (err)
	57	return err;
	58
e9be9d5e MS	59	err = ovl_want_write(dentry);
	60	if (err)
	61	goto out;
	62
03bea604 MS	63	if (attr->ia_valid & ATTR_SIZE) {
	64	struct inode *realinode = d_inode(ovl_dentry_real(dentry));
	65
	66	err = -ETXTBSY;
	67	if (atomic_read(&realinode->i_writecount) < 0)
	68	goto out_drop_write;
	69	}
	70
acff81ec MS	71	err = ovl_copy_up(dentry);
acff81ec MS	72	if (!err) {
03bea604 MS	73	struct inode *winode = NULL;
03bea604 MS	74
acff81ec MS	75	upperdentry = ovl_dentry_upper(dentry);
acff81ec MS	76
03bea604 MS	77	if (attr->ia_valid & ATTR_SIZE) {
	78	winode = d_inode(upperdentry);
	79	err = get_write_access(winode);
	80	if (err)
	81	goto out_drop_write;
	82	}
	83
b99c2d91 MS	84	if (attr->ia_valid & (ATTR_KILL_SUID\|ATTR_KILL_SGID))
	85	attr->ia_valid &= ~ATTR_MODE;
	86
5955102c	87	inode_lock(upperdentry->d_inode);
1175b6b8	88	old_cred = ovl_override_creds(dentry->d_sb);
e9be9d5e	89	err = notify_change(upperdentry, attr, NULL);
1175b6b8	90	revert_creds(old_cred);
b81de061 KK	91	if (!err)
b81de061 KK	92	ovl_copyattr(upperdentry->d_inode, dentry->d_inode);
5955102c	93	inode_unlock(upperdentry->d_inode);
03bea604 MS	94
	95	if (winode)
	96	put_write_access(winode);
e9be9d5e	97	}
03bea604	98	out_drop_write:
e9be9d5e MS	99	ovl_drop_write(dentry);
	100	out:
	101	return err;
	102	}
	103
	104	static int ovl_getattr(struct vfsmount mnt, struct dentry dentry,
	105	struct kstat *stat)
	106	{
	107	struct path realpath;
1175b6b8 VG	108	const struct cred *old_cred;
1175b6b8 VG	109	int err;
e9be9d5e MS	110
e9be9d5e MS	111	ovl_path_real(dentry, &realpath);
1175b6b8 VG	112	old_cred = ovl_override_creds(dentry->d_sb);
	113	err = vfs_getattr(&realpath, stat);
	114	revert_creds(old_cred);
	115	return err;
e9be9d5e MS	116	}
	117
	118	int ovl_permission(struct inode *inode, int mask)
	119	{
e9be9d5e	120	bool is_upper;
39b681f8	121	struct inode *realinode = ovl_inode_real(inode, &is_upper);
c0ca3d70	122	const struct cred *old_cred;
e9be9d5e MS	123	int err;
e9be9d5e MS	124
e9be9d5e	125	/* Careful in RCU walk mode */
e9be9d5e MS	126	if (!realinode) {
e9be9d5e MS	127	WARN_ON(!(mask & MAY_NOT_BLOCK));
a999d7e1	128	return -ECHILD;
e9be9d5e MS	129	}
e9be9d5e MS	130
c0ca3d70 VG	131	/*
	132	* Check overlay inode with the creds of task and underlying inode
	133	* with creds of mounter
	134	*/
	135	err = generic_permission(inode, mask);
	136	if (err)
	137	return err;
	138
	139	old_cred = ovl_override_creds(inode->i_sb);
500cac3c	140	if (!is_upper && !special_file(realinode->i_mode) && mask & MAY_WRITE) {
754f8cb7	141	mask &= ~(MAY_WRITE \| MAY_APPEND);
500cac3c VG	142	/* Make sure mounter can read file for copy up later */
	143	mask \|= MAY_READ;
	144	}
9c630ebe	145	err = inode_permission(realinode, mask);
c0ca3d70 VG	146	revert_creds(old_cred);
	147
	148	return err;
e9be9d5e MS	149	}
e9be9d5e MS	150
6b255391	151	static const char ovl_get_link(struct dentry dentry,
fceef393 AV	152	struct inode *inode,
fceef393 AV	153	struct delayed_call *done)
e9be9d5e	154	{
e9be9d5e MS	155	struct dentry *realdentry;
e9be9d5e MS	156	struct inode *realinode;
1175b6b8 VG	157	const struct cred *old_cred;
1175b6b8 VG	158	const char *p;
e9be9d5e	159
6b255391 AV	160	if (!dentry)
	161	return ERR_PTR(-ECHILD);
	162
e9be9d5e MS	163	realdentry = ovl_dentry_real(dentry);
	164	realinode = realdentry->d_inode;
	165
6b255391	166	if (WARN_ON(!realinode->i_op->get_link))
e9be9d5e MS	167	return ERR_PTR(-EPERM);
e9be9d5e MS	168
1175b6b8 VG	169	old_cred = ovl_override_creds(dentry->d_sb);
	170	p = realinode->i_op->get_link(realdentry, realinode, done);
	171	revert_creds(old_cred);
	172	return p;
e9be9d5e MS	173	}
	174
	175	static int ovl_readlink(struct dentry dentry, char __user buf, int bufsiz)
	176	{
	177	struct path realpath;
	178	struct inode *realinode;
1175b6b8 VG	179	const struct cred *old_cred;
1175b6b8 VG	180	int err;
e9be9d5e MS	181
	182	ovl_path_real(dentry, &realpath);
	183	realinode = realpath.dentry->d_inode;
	184
	185	if (!realinode->i_op->readlink)
	186	return -EINVAL;
	187
1175b6b8 VG	188	old_cred = ovl_override_creds(dentry->d_sb);
	189	err = realinode->i_op->readlink(realpath.dentry, buf, bufsiz);
	190	revert_creds(old_cred);
	191	return err;
e9be9d5e MS	192	}
e9be9d5e MS	193
e9be9d5e MS	194	static bool ovl_is_private_xattr(const char *name)
e9be9d5e MS	195	{
d837a49b MS	196	#define OVL_XATTR_PRE_NAME OVL_XATTR_PREFIX "."
	197	return strncmp(name, OVL_XATTR_PRE_NAME,
	198	sizeof(OVL_XATTR_PRE_NAME) - 1) == 0;
e9be9d5e MS	199	}
e9be9d5e MS	200
3767e255 AV	201	int ovl_setxattr(struct dentry dentry, struct inode inode,
	202	const char name, const void value,
	203	size_t size, int flags)
e9be9d5e MS	204	{
	205	int err;
	206	struct dentry *upperdentry;
1175b6b8	207	const struct cred *old_cred;
e9be9d5e MS	208
	209	err = ovl_want_write(dentry);
	210	if (err)
	211	goto out;
	212
e9be9d5e MS	213	err = ovl_copy_up(dentry);
	214	if (err)
	215	goto out_drop_write;
	216
	217	upperdentry = ovl_dentry_upper(dentry);
1175b6b8	218	old_cred = ovl_override_creds(dentry->d_sb);
e9be9d5e	219	err = vfs_setxattr(upperdentry, name, value, size, flags);
1175b6b8	220	revert_creds(old_cred);
e9be9d5e MS	221
	222	out_drop_write:
	223	ovl_drop_write(dentry);
	224	out:
	225	return err;
	226	}
	227
ce23e640 AV	228	ssize_t ovl_getxattr(struct dentry dentry, struct inode inode,
ce23e640 AV	229	const char name, void value, size_t size)
e9be9d5e	230	{
b581755b	231	struct dentry *realdentry = ovl_dentry_real(dentry);
1175b6b8 VG	232	ssize_t res;
1175b6b8 VG	233	const struct cred *old_cred;
52148463	234
b581755b	235	if (ovl_is_private_xattr(name))
e9be9d5e MS	236	return -ENODATA;
e9be9d5e MS	237
1175b6b8 VG	238	old_cred = ovl_override_creds(dentry->d_sb);
	239	res = vfs_getxattr(realdentry, name, value, size);
	240	revert_creds(old_cred);
	241	return res;
e9be9d5e MS	242	}
	243
	244	ssize_t ovl_listxattr(struct dentry dentry, char list, size_t size)
	245	{
b581755b	246	struct dentry *realdentry = ovl_dentry_real(dentry);
e9be9d5e MS	247	ssize_t res;
e9be9d5e MS	248	int off;
1175b6b8	249	const struct cred *old_cred;
e9be9d5e	250
1175b6b8	251	old_cred = ovl_override_creds(dentry->d_sb);
b581755b	252	res = vfs_listxattr(realdentry, list, size);
1175b6b8	253	revert_creds(old_cred);
e9be9d5e MS	254	if (res <= 0 \|\| size == 0)
	255	return res;
	256
e9be9d5e MS	257	/* filter out private xattrs */
	258	for (off = 0; off < res;) {
	259	char *s = list + off;
	260	size_t slen = strlen(s) + 1;
	261
	262	BUG_ON(off + slen > res);
	263
	264	if (ovl_is_private_xattr(s)) {
	265	res -= slen;
	266	memmove(s, s + slen, res - off);
	267	} else {
	268	off += slen;
	269	}
	270	}
	271
	272	return res;
	273	}
	274
	275	int ovl_removexattr(struct dentry dentry, const char name)
	276	{
	277	int err;
	278	struct path realpath;
52148463	279	enum ovl_path_type type = ovl_path_real(dentry, &realpath);
1175b6b8	280	const struct cred *old_cred;
e9be9d5e MS	281
	282	err = ovl_want_write(dentry);
	283	if (err)
	284	goto out;
	285
52148463	286	err = -ENODATA;
b581755b	287	if (ovl_is_private_xattr(name))
e9be9d5e MS	288	goto out_drop_write;
e9be9d5e MS	289
1afaba1e	290	if (!OVL_TYPE_UPPER(type)) {
e9be9d5e MS	291	err = vfs_getxattr(realpath.dentry, name, NULL, 0);
	292	if (err < 0)
	293	goto out_drop_write;
	294
	295	err = ovl_copy_up(dentry);
	296	if (err)
	297	goto out_drop_write;
	298
	299	ovl_path_upper(dentry, &realpath);
	300	}
	301
1175b6b8	302	old_cred = ovl_override_creds(dentry->d_sb);
e9be9d5e	303	err = vfs_removexattr(realpath.dentry, name);
1175b6b8	304	revert_creds(old_cred);
e9be9d5e MS	305	out_drop_write:
	306	ovl_drop_write(dentry);
	307	out:
	308	return err;
	309	}
	310
39a25b2b VG	311	struct posix_acl ovl_get_acl(struct inode inode, int type)
39a25b2b VG	312	{
39b681f8	313	struct inode *realinode = ovl_inode_real(inode, NULL);
1175b6b8 VG	314	const struct cred *old_cred;
1175b6b8 VG	315	struct posix_acl *acl;
39a25b2b	316
39a25b2b VG	317	if (!IS_POSIXACL(realinode))
	318	return NULL;
	319
	320	if (!realinode->i_op->get_acl)
	321	return NULL;
	322
1175b6b8 VG	323	old_cred = ovl_override_creds(inode->i_sb);
	324	acl = realinode->i_op->get_acl(realinode, type);
	325	revert_creds(old_cred);
	326
	327	return acl;
39a25b2b VG	328	}
39a25b2b VG	329
e9be9d5e MS	330	static bool ovl_open_need_copy_up(int flags, enum ovl_path_type type,
	331	struct dentry *realdentry)
	332	{
1afaba1e	333	if (OVL_TYPE_UPPER(type))
e9be9d5e MS	334	return false;
	335
	336	if (special_file(realdentry->d_inode->i_mode))
	337	return false;
	338
	339	if (!(OPEN_FMODE(flags) & FMODE_WRITE) && !(flags & O_TRUNC))
	340	return false;
	341
	342	return true;
	343	}
	344
2d902671	345	int ovl_open_maybe_copy_up(struct dentry *dentry, unsigned int file_flags)
e9be9d5e	346	{
2d902671	347	int err = 0;
e9be9d5e MS	348	struct path realpath;
e9be9d5e MS	349	enum ovl_path_type type;
e9be9d5e MS	350
e9be9d5e MS	351	type = ovl_path_real(dentry, &realpath);
4bacc9c9	352	if (ovl_open_need_copy_up(file_flags, type, realpath.dentry)) {
e9be9d5e	353	err = ovl_want_write(dentry);
2d902671 MS	354	if (!err) {
	355	if (file_flags & O_TRUNC)
	356	err = ovl_copy_up_truncate(dentry);
	357	else
	358	err = ovl_copy_up(dentry);
	359	ovl_drop_write(dentry);
	360	}
e9be9d5e MS	361	}
e9be9d5e MS	362
2d902671	363	return err;
e9be9d5e MS	364	}
e9be9d5e MS	365
d719e8f2 MS	366	int ovl_update_time(struct inode inode, struct timespec ts, int flags)
	367	{
	368	struct dentry *alias;
	369	struct path upperpath;
	370
	371	if (!(flags & S_ATIME))
	372	return 0;
	373
	374	alias = d_find_any_alias(inode);
	375	if (!alias)
	376	return 0;
	377
	378	ovl_path_upper(alias, &upperpath);
	379	if (upperpath.dentry) {
	380	touch_atime(&upperpath);
	381	inode->i_atime = d_inode(upperpath.dentry)->i_atime;
	382	}
	383
	384	dput(alias);
	385
	386	return 0;
	387	}
	388
e9be9d5e MS	389	static const struct inode_operations ovl_file_inode_operations = {
	390	.setattr = ovl_setattr,
	391	.permission = ovl_permission,
	392	.getattr = ovl_getattr,
d837a49b	393	.setxattr = generic_setxattr,
e9be9d5e MS	394	.getxattr = ovl_getxattr,
	395	.listxattr = ovl_listxattr,
	396	.removexattr = ovl_removexattr,
39a25b2b	397	.get_acl = ovl_get_acl,
d719e8f2	398	.update_time = ovl_update_time,
e9be9d5e MS	399	};
	400
	401	static const struct inode_operations ovl_symlink_inode_operations = {
	402	.setattr = ovl_setattr,
6b255391	403	.get_link = ovl_get_link,
e9be9d5e MS	404	.readlink = ovl_readlink,
e9be9d5e MS	405	.getattr = ovl_getattr,
d837a49b	406	.setxattr = generic_setxattr,
e9be9d5e MS	407	.getxattr = ovl_getxattr,
	408	.listxattr = ovl_listxattr,
	409	.removexattr = ovl_removexattr,
d719e8f2	410	.update_time = ovl_update_time,
e9be9d5e MS	411	};
e9be9d5e MS	412
51f7e52d	413	static void ovl_fill_inode(struct inode *inode, umode_t mode)
e9be9d5e	414	{
e9be9d5e MS	415	inode->i_ino = get_next_ino();
e9be9d5e MS	416	inode->i_mode = mode;
d719e8f2	417	inode->i_flags \|= S_NOCMTIME;
e9be9d5e	418
07a2daab	419	mode &= S_IFMT;
e9be9d5e MS	420	switch (mode) {
e9be9d5e MS	421	case S_IFDIR:
e9be9d5e MS	422	inode->i_op = &ovl_dir_inode_operations;
	423	inode->i_fop = &ovl_dir_operations;
	424	break;
	425
	426	case S_IFLNK:
	427	inode->i_op = &ovl_symlink_inode_operations;
	428	break;
	429
51f7e52d MS	430	default:
	431	WARN(1, "illegal file type: %i\n", mode);
	432	/* Fall through */
	433
e9be9d5e MS	434	case S_IFREG:
	435	case S_IFSOCK:
	436	case S_IFBLK:
	437	case S_IFCHR:
	438	case S_IFIFO:
	439	inode->i_op = &ovl_file_inode_operations;
	440	break;
51f7e52d MS	441	}
51f7e52d MS	442	}
e9be9d5e	443
51f7e52d MS	444	struct inode ovl_new_inode(struct super_block sb, umode_t mode)
	445	{
	446	struct inode *inode;
	447
	448	inode = new_inode(sb);
	449	if (inode)
	450	ovl_fill_inode(inode, mode);
	451
	452	return inode;
	453	}
	454
	455	static int ovl_inode_test(struct inode inode, void data)
	456	{
	457	return ovl_inode_real(inode, NULL) == data;
	458	}
	459
	460	static int ovl_inode_set(struct inode inode, void data)
	461	{
	462	inode->i_private = (void *) (((unsigned long) data) \| OVL_ISUPPER_MASK);
	463	return 0;
	464	}
	465
	466	struct inode ovl_get_inode(struct super_block sb, struct inode *realinode)
	467
	468	{
	469	struct inode *inode;
	470
	471	inode = iget5_locked(sb, (unsigned long) realinode,
	472	ovl_inode_test, ovl_inode_set, realinode);
	473	if (inode && inode->i_state & I_NEW) {
	474	ovl_fill_inode(inode, realinode->i_mode);
	475	set_nlink(inode, realinode->i_nlink);
	476	unlock_new_inode(inode);
e9be9d5e MS	477	}
	478
	479	return inode;
e9be9d5e	480	}