[deliverable/linux.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 <linux/posix_acl.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;
}

bool ovl_is_private_xattr(const char *name)
{
	return strncmp(name, OVL_XATTR_PREFIX,
		       sizeof(OVL_XATTR_PREFIX) - 1) == 0;
}

int ovl_xattr_set(struct dentry *dentry, const char *name, const void *value,
		  size_t size, int flags)
{
	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;

	if (!value && !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;

	if (!OVL_TYPE_UPPER(type))
		ovl_path_upper(dentry, &realpath);

	old_cred = ovl_override_creds(dentry->d_sb);
	if (value)
		err = vfs_setxattr(realpath.dentry, name, value, size, flags);
	else {
		WARN_ON(flags != XATTR_REPLACE);
		err = vfs_removexattr(realpath.dentry, name);
	}
	revert_creds(old_cred);

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

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

	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;
	size_t len;
	char *s;
	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 (s = list, len = res; len;) {
		size_t slen = strnlen(s, len) + 1;

		/* underlying fs providing us with an broken xattr list? */
		if (WARN_ON(slen > len))
			return -EIO;

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

	return res;
}

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_ENABLED(CONFIG_FS_POSIX_ACL) || !IS_POSIXACL(realinode))
		return NULL;

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

	old_cred = ovl_override_creds(inode->i_sb);
	acl = 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	= generic_getxattr,
	.listxattr	= ovl_listxattr,
	.removexattr	= generic_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	= generic_getxattr,
	.listxattr	= ovl_listxattr,
	.removexattr	= generic_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;
#ifdef CONFIG_FS_POSIX_ACL
	inode->i_acl = inode->i_default_acl = ACL_DONT_CACHE;
#endif

	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>
5201dc44	13	#include <linux/posix_acl.h>
e9be9d5e MS	14	#include "overlayfs.h"
e9be9d5e MS	15
0f7ff2da	16	static int ovl_copy_up_truncate(struct dentry *dentry)
e9be9d5e MS	17	{
	18	int err;
	19	struct dentry *parent;
	20	struct kstat stat;
	21	struct path lowerpath;
	22
	23	parent = dget_parent(dentry);
	24	err = ovl_copy_up(parent);
	25	if (err)
	26	goto out_dput_parent;
	27
	28	ovl_path_lower(dentry, &lowerpath);
	29	err = vfs_getattr(&lowerpath, &stat);
	30	if (err)
	31	goto out_dput_parent;
	32
0f7ff2da AV	33	stat.size = 0;
0f7ff2da AV	34	err = ovl_copy_up_one(parent, dentry, &lowerpath, &stat);
e9be9d5e MS	35
	36	out_dput_parent:
	37	dput(parent);
	38	return err;
	39	}
	40
	41	int ovl_setattr(struct dentry dentry, struct iattr attr)
	42	{
	43	int err;
	44	struct dentry *upperdentry;
1175b6b8	45	const struct cred *old_cred;
e9be9d5e	46
cf9a6784 MS	47	/*
	48	* Check for permissions before trying to copy-up. This is redundant
	49	* since it will be rechecked later by ->setattr() on upper dentry. But
	50	* without this, copy-up can be triggered by just about anybody.
	51	*
	52	* We don't initialize inode->size, which just means that
	53	* inode_newsize_ok() will always check against MAX_LFS_FILESIZE and not
	54	* check for a swapfile (which this won't be anyway).
	55	*/
	56	err = inode_change_ok(dentry->d_inode, attr);
	57	if (err)
	58	return err;
	59
e9be9d5e MS	60	err = ovl_want_write(dentry);
	61	if (err)
	62	goto out;
	63
03bea604 MS	64	if (attr->ia_valid & ATTR_SIZE) {
	65	struct inode *realinode = d_inode(ovl_dentry_real(dentry));
	66
	67	err = -ETXTBSY;
	68	if (atomic_read(&realinode->i_writecount) < 0)
	69	goto out_drop_write;
	70	}
	71
acff81ec MS	72	err = ovl_copy_up(dentry);
acff81ec MS	73	if (!err) {
03bea604 MS	74	struct inode *winode = NULL;
03bea604 MS	75
acff81ec MS	76	upperdentry = ovl_dentry_upper(dentry);
acff81ec MS	77
03bea604 MS	78	if (attr->ia_valid & ATTR_SIZE) {
	79	winode = d_inode(upperdentry);
	80	err = get_write_access(winode);
	81	if (err)
	82	goto out_drop_write;
	83	}
	84
b99c2d91 MS	85	if (attr->ia_valid & (ATTR_KILL_SUID\|ATTR_KILL_SGID))
	86	attr->ia_valid &= ~ATTR_MODE;
	87
5955102c	88	inode_lock(upperdentry->d_inode);
1175b6b8	89	old_cred = ovl_override_creds(dentry->d_sb);
e9be9d5e	90	err = notify_change(upperdentry, attr, NULL);
1175b6b8	91	revert_creds(old_cred);
b81de061 KK	92	if (!err)
b81de061 KK	93	ovl_copyattr(upperdentry->d_inode, dentry->d_inode);
5955102c	94	inode_unlock(upperdentry->d_inode);
03bea604 MS	95
	96	if (winode)
	97	put_write_access(winode);
e9be9d5e	98	}
03bea604	99	out_drop_write:
e9be9d5e MS	100	ovl_drop_write(dentry);
	101	out:
	102	return err;
	103	}
	104
	105	static int ovl_getattr(struct vfsmount mnt, struct dentry dentry,
	106	struct kstat *stat)
	107	{
	108	struct path realpath;
1175b6b8 VG	109	const struct cred *old_cred;
1175b6b8 VG	110	int err;
e9be9d5e MS	111
e9be9d5e MS	112	ovl_path_real(dentry, &realpath);
1175b6b8 VG	113	old_cred = ovl_override_creds(dentry->d_sb);
	114	err = vfs_getattr(&realpath, stat);
	115	revert_creds(old_cred);
	116	return err;
e9be9d5e MS	117	}
	118
	119	int ovl_permission(struct inode *inode, int mask)
	120	{
e9be9d5e	121	bool is_upper;
39b681f8	122	struct inode *realinode = ovl_inode_real(inode, &is_upper);
c0ca3d70	123	const struct cred *old_cred;
e9be9d5e MS	124	int err;
e9be9d5e MS	125
e9be9d5e	126	/* Careful in RCU walk mode */
e9be9d5e MS	127	if (!realinode) {
e9be9d5e MS	128	WARN_ON(!(mask & MAY_NOT_BLOCK));
a999d7e1	129	return -ECHILD;
e9be9d5e MS	130	}
e9be9d5e MS	131
c0ca3d70 VG	132	/*
	133	* Check overlay inode with the creds of task and underlying inode
	134	* with creds of mounter
	135	*/
	136	err = generic_permission(inode, mask);
	137	if (err)
	138	return err;
	139
	140	old_cred = ovl_override_creds(inode->i_sb);
500cac3c	141	if (!is_upper && !special_file(realinode->i_mode) && mask & MAY_WRITE) {
754f8cb7	142	mask &= ~(MAY_WRITE \| MAY_APPEND);
500cac3c VG	143	/* Make sure mounter can read file for copy up later */
	144	mask \|= MAY_READ;
	145	}
9c630ebe	146	err = inode_permission(realinode, mask);
c0ca3d70 VG	147	revert_creds(old_cred);
	148
	149	return err;
e9be9d5e MS	150	}
e9be9d5e MS	151
6b255391	152	static const char ovl_get_link(struct dentry dentry,
fceef393 AV	153	struct inode *inode,
fceef393 AV	154	struct delayed_call *done)
e9be9d5e	155	{
e9be9d5e MS	156	struct dentry *realdentry;
e9be9d5e MS	157	struct inode *realinode;
1175b6b8 VG	158	const struct cred *old_cred;
1175b6b8 VG	159	const char *p;
e9be9d5e	160
6b255391 AV	161	if (!dentry)
	162	return ERR_PTR(-ECHILD);
	163
e9be9d5e MS	164	realdentry = ovl_dentry_real(dentry);
	165	realinode = realdentry->d_inode;
	166
6b255391	167	if (WARN_ON(!realinode->i_op->get_link))
e9be9d5e MS	168	return ERR_PTR(-EPERM);
e9be9d5e MS	169
1175b6b8 VG	170	old_cred = ovl_override_creds(dentry->d_sb);
	171	p = realinode->i_op->get_link(realdentry, realinode, done);
	172	revert_creds(old_cred);
	173	return p;
e9be9d5e MS	174	}
	175
	176	static int ovl_readlink(struct dentry dentry, char __user buf, int bufsiz)
	177	{
	178	struct path realpath;
	179	struct inode *realinode;
1175b6b8 VG	180	const struct cred *old_cred;
1175b6b8 VG	181	int err;
e9be9d5e MS	182
	183	ovl_path_real(dentry, &realpath);
	184	realinode = realpath.dentry->d_inode;
	185
	186	if (!realinode->i_op->readlink)
	187	return -EINVAL;
	188
1175b6b8 VG	189	old_cred = ovl_override_creds(dentry->d_sb);
	190	err = realinode->i_op->readlink(realpath.dentry, buf, bufsiz);
	191	revert_creds(old_cred);
	192	return err;
e9be9d5e MS	193	}
e9be9d5e MS	194
0956254a	195	bool ovl_is_private_xattr(const char *name)
e9be9d5e	196	{
fe2b7595 AG	197	return strncmp(name, OVL_XATTR_PREFIX,
fe2b7595 AG	198	sizeof(OVL_XATTR_PREFIX) - 1) == 0;
e9be9d5e MS	199	}
e9be9d5e MS	200
0e585ccc AG	201	int ovl_xattr_set(struct dentry dentry, const char name, const void *value,
0e585ccc AG	202	size_t size, int flags)
e9be9d5e MS	203	{
e9be9d5e MS	204	int err;
0e585ccc AG	205	struct path realpath;
0e585ccc AG	206	enum ovl_path_type type = ovl_path_real(dentry, &realpath);
1175b6b8	207	const struct cred *old_cred;
e9be9d5e MS	208
	209	err = ovl_want_write(dentry);
	210	if (err)
	211	goto out;
	212
0e585ccc AG	213	if (!value && !OVL_TYPE_UPPER(type)) {
	214	err = vfs_getxattr(realpath.dentry, name, NULL, 0);
	215	if (err < 0)
	216	goto out_drop_write;
	217	}
	218
e9be9d5e MS	219	err = ovl_copy_up(dentry);
	220	if (err)
	221	goto out_drop_write;
	222
0e585ccc AG	223	if (!OVL_TYPE_UPPER(type))
	224	ovl_path_upper(dentry, &realpath);
	225
1175b6b8	226	old_cred = ovl_override_creds(dentry->d_sb);
0e585ccc AG	227	if (value)
	228	err = vfs_setxattr(realpath.dentry, name, value, size, flags);
	229	else {
	230	WARN_ON(flags != XATTR_REPLACE);
	231	err = vfs_removexattr(realpath.dentry, name);
	232	}
1175b6b8	233	revert_creds(old_cred);
e9be9d5e MS	234
	235	out_drop_write:
	236	ovl_drop_write(dentry);
	237	out:
	238	return err;
	239	}
	240
0eb45fc3 AG	241	int ovl_xattr_get(struct dentry dentry, const char name,
0eb45fc3 AG	242	void *value, size_t size)
e9be9d5e	243	{
b581755b	244	struct dentry *realdentry = ovl_dentry_real(dentry);
1175b6b8 VG	245	ssize_t res;
1175b6b8 VG	246	const struct cred *old_cred;
52148463	247
1175b6b8 VG	248	old_cred = ovl_override_creds(dentry->d_sb);
	249	res = vfs_getxattr(realdentry, name, value, size);
	250	revert_creds(old_cred);
	251	return res;
e9be9d5e MS	252	}
	253
	254	ssize_t ovl_listxattr(struct dentry dentry, char list, size_t size)
	255	{
b581755b	256	struct dentry *realdentry = ovl_dentry_real(dentry);
e9be9d5e	257	ssize_t res;
7cb35119 MS	258	size_t len;
7cb35119 MS	259	char *s;
1175b6b8	260	const struct cred *old_cred;
e9be9d5e	261
1175b6b8	262	old_cred = ovl_override_creds(dentry->d_sb);
b581755b	263	res = vfs_listxattr(realdentry, list, size);
1175b6b8	264	revert_creds(old_cred);
e9be9d5e MS	265	if (res <= 0 \|\| size == 0)
	266	return res;
	267
e9be9d5e	268	/* filter out private xattrs */
7cb35119 MS	269	for (s = list, len = res; len;) {
7cb35119 MS	270	size_t slen = strnlen(s, len) + 1;
e9be9d5e	271
7cb35119 MS	272	/* underlying fs providing us with an broken xattr list? */
	273	if (WARN_ON(slen > len))
	274	return -EIO;
e9be9d5e	275
7cb35119	276	len -= slen;
e9be9d5e MS	277	if (ovl_is_private_xattr(s)) {
e9be9d5e MS	278	res -= slen;
7cb35119	279	memmove(s, s + slen, len);
e9be9d5e	280	} else {
7cb35119	281	s += slen;
e9be9d5e MS	282	}
	283	}
	284
	285	return res;
	286	}
	287
39a25b2b VG	288	struct posix_acl ovl_get_acl(struct inode inode, int type)
39a25b2b VG	289	{
39b681f8	290	struct inode *realinode = ovl_inode_real(inode, NULL);
1175b6b8 VG	291	const struct cred *old_cred;
1175b6b8 VG	292	struct posix_acl *acl;
39a25b2b	293
5201dc44	294	if (!IS_ENABLED(CONFIG_FS_POSIX_ACL) \|\| !IS_POSIXACL(realinode))
39a25b2b VG	295	return NULL;
	296
	297	if (!realinode->i_op->get_acl)
	298	return NULL;
	299
1175b6b8	300	old_cred = ovl_override_creds(inode->i_sb);
5201dc44	301	acl = get_acl(realinode, type);
1175b6b8 VG	302	revert_creds(old_cred);
	303
	304	return acl;
39a25b2b VG	305	}
39a25b2b VG	306
e9be9d5e MS	307	static bool ovl_open_need_copy_up(int flags, enum ovl_path_type type,
	308	struct dentry *realdentry)
	309	{
1afaba1e	310	if (OVL_TYPE_UPPER(type))
e9be9d5e MS	311	return false;
	312
	313	if (special_file(realdentry->d_inode->i_mode))
	314	return false;
	315
	316	if (!(OPEN_FMODE(flags) & FMODE_WRITE) && !(flags & O_TRUNC))
	317	return false;
	318
	319	return true;
	320	}
	321
2d902671	322	int ovl_open_maybe_copy_up(struct dentry *dentry, unsigned int file_flags)
e9be9d5e	323	{
2d902671	324	int err = 0;
e9be9d5e MS	325	struct path realpath;
e9be9d5e MS	326	enum ovl_path_type type;
e9be9d5e MS	327
e9be9d5e MS	328	type = ovl_path_real(dentry, &realpath);
4bacc9c9	329	if (ovl_open_need_copy_up(file_flags, type, realpath.dentry)) {
e9be9d5e	330	err = ovl_want_write(dentry);
2d902671 MS	331	if (!err) {
	332	if (file_flags & O_TRUNC)
	333	err = ovl_copy_up_truncate(dentry);
	334	else
	335	err = ovl_copy_up(dentry);
	336	ovl_drop_write(dentry);
	337	}
e9be9d5e MS	338	}
e9be9d5e MS	339
2d902671	340	return err;
e9be9d5e MS	341	}
e9be9d5e MS	342
d719e8f2 MS	343	int ovl_update_time(struct inode inode, struct timespec ts, int flags)
	344	{
	345	struct dentry *alias;
	346	struct path upperpath;
	347
	348	if (!(flags & S_ATIME))
	349	return 0;
	350
	351	alias = d_find_any_alias(inode);
	352	if (!alias)
	353	return 0;
	354
	355	ovl_path_upper(alias, &upperpath);
	356	if (upperpath.dentry) {
	357	touch_atime(&upperpath);
	358	inode->i_atime = d_inode(upperpath.dentry)->i_atime;
	359	}
	360
	361	dput(alias);
	362
	363	return 0;
	364	}
	365
e9be9d5e MS	366	static const struct inode_operations ovl_file_inode_operations = {
	367	.setattr = ovl_setattr,
	368	.permission = ovl_permission,
	369	.getattr = ovl_getattr,
d837a49b	370	.setxattr = generic_setxattr,
0eb45fc3	371	.getxattr = generic_getxattr,
e9be9d5e	372	.listxattr = ovl_listxattr,
0e585ccc	373	.removexattr = generic_removexattr,
39a25b2b	374	.get_acl = ovl_get_acl,
d719e8f2	375	.update_time = ovl_update_time,
e9be9d5e MS	376	};
	377
	378	static const struct inode_operations ovl_symlink_inode_operations = {
	379	.setattr = ovl_setattr,
6b255391	380	.get_link = ovl_get_link,
e9be9d5e MS	381	.readlink = ovl_readlink,
e9be9d5e MS	382	.getattr = ovl_getattr,
d837a49b	383	.setxattr = generic_setxattr,
0eb45fc3	384	.getxattr = generic_getxattr,
e9be9d5e	385	.listxattr = ovl_listxattr,
0e585ccc	386	.removexattr = generic_removexattr,
d719e8f2	387	.update_time = ovl_update_time,
e9be9d5e MS	388	};
e9be9d5e MS	389
51f7e52d	390	static void ovl_fill_inode(struct inode *inode, umode_t mode)
e9be9d5e	391	{
e9be9d5e MS	392	inode->i_ino = get_next_ino();
e9be9d5e MS	393	inode->i_mode = mode;
d719e8f2	394	inode->i_flags \|= S_NOCMTIME;
2a3a2a3f MS	395	#ifdef CONFIG_FS_POSIX_ACL
	396	inode->i_acl = inode->i_default_acl = ACL_DONT_CACHE;
	397	#endif
e9be9d5e	398
07a2daab	399	mode &= S_IFMT;
e9be9d5e MS	400	switch (mode) {
e9be9d5e MS	401	case S_IFDIR:
e9be9d5e MS	402	inode->i_op = &ovl_dir_inode_operations;
	403	inode->i_fop = &ovl_dir_operations;
	404	break;
	405
	406	case S_IFLNK:
	407	inode->i_op = &ovl_symlink_inode_operations;
	408	break;
	409
51f7e52d MS	410	default:
	411	WARN(1, "illegal file type: %i\n", mode);
	412	/* Fall through */
	413
e9be9d5e MS	414	case S_IFREG:
	415	case S_IFSOCK:
	416	case S_IFBLK:
	417	case S_IFCHR:
	418	case S_IFIFO:
	419	inode->i_op = &ovl_file_inode_operations;
	420	break;
51f7e52d MS	421	}
51f7e52d MS	422	}
e9be9d5e	423
51f7e52d MS	424	struct inode ovl_new_inode(struct super_block sb, umode_t mode)
	425	{
	426	struct inode *inode;
	427
	428	inode = new_inode(sb);
	429	if (inode)
	430	ovl_fill_inode(inode, mode);
	431
	432	return inode;
	433	}
	434
	435	static int ovl_inode_test(struct inode inode, void data)
	436	{
	437	return ovl_inode_real(inode, NULL) == data;
	438	}
	439
	440	static int ovl_inode_set(struct inode inode, void data)
	441	{
	442	inode->i_private = (void *) (((unsigned long) data) \| OVL_ISUPPER_MASK);
	443	return 0;
	444	}
	445
	446	struct inode ovl_get_inode(struct super_block sb, struct inode *realinode)
	447
	448	{
	449	struct inode *inode;
	450
	451	inode = iget5_locked(sb, (unsigned long) realinode,
	452	ovl_inode_test, ovl_inode_set, realinode);
	453	if (inode && inode->i_state & I_NEW) {
	454	ovl_fill_inode(inode, realinode->i_mode);
	455	set_nlink(inode, realinode->i_nlink);
	456	unlock_new_inode(inode);
e9be9d5e MS	457	}
	458
	459	return inode;
e9be9d5e	460	}