Orange Pi5 kernel

^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   1) // SPDX-License-Identifier: GPL-2.0-only
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   2) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   3)  * fs/kernfs/inode.c - kernfs inode implementation
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   4)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   5)  * Copyright (c) 2001-3 Patrick Mochel
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   6)  * Copyright (c) 2007 SUSE Linux Products GmbH
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   7)  * Copyright (c) 2007, 2013 Tejun Heo <tj@kernel.org>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   8)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   9) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  10) #include <linux/pagemap.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  11) #include <linux/backing-dev.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  12) #include <linux/capability.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  13) #include <linux/errno.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  14) #include <linux/slab.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  15) #include <linux/xattr.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  16) #include <linux/security.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  17) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  18) #include "kernfs-internal.h"
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  19) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  20) static const struct address_space_operations kernfs_aops = {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  21) 	.readpage	= simple_readpage,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  22) 	.write_begin	= simple_write_begin,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  23) 	.write_end	= simple_write_end,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  24) };
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  25) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  26) static const struct inode_operations kernfs_iops = {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  27) 	.permission	= kernfs_iop_permission,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  28) 	.setattr	= kernfs_iop_setattr,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  29) 	.getattr	= kernfs_iop_getattr,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  30) 	.listxattr	= kernfs_iop_listxattr,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  31) };
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  32) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  33) static struct kernfs_iattrs *__kernfs_iattrs(struct kernfs_node *kn, int alloc)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  34) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  35) 	static DEFINE_MUTEX(iattr_mutex);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  36) 	struct kernfs_iattrs *ret;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  37) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  38) 	mutex_lock(&iattr_mutex);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  39) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  40) 	if (kn->iattr || !alloc)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  41) 		goto out_unlock;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  42) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  43) 	kn->iattr = kmem_cache_zalloc(kernfs_iattrs_cache, GFP_KERNEL);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  44) 	if (!kn->iattr)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  45) 		goto out_unlock;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  46) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  47) 	/* assign default attributes */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  48) 	kn->iattr->ia_uid = GLOBAL_ROOT_UID;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  49) 	kn->iattr->ia_gid = GLOBAL_ROOT_GID;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  50) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  51) 	ktime_get_real_ts64(&kn->iattr->ia_atime);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  52) 	kn->iattr->ia_mtime = kn->iattr->ia_atime;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  53) 	kn->iattr->ia_ctime = kn->iattr->ia_atime;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  54) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  55) 	simple_xattrs_init(&kn->iattr->xattrs);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  56) 	atomic_set(&kn->iattr->nr_user_xattrs, 0);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  57) 	atomic_set(&kn->iattr->user_xattr_size, 0);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  58) out_unlock:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  59) 	ret = kn->iattr;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  60) 	mutex_unlock(&iattr_mutex);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  61) 	return ret;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  62) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  63) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  64) static struct kernfs_iattrs *kernfs_iattrs(struct kernfs_node *kn)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  65) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  66) 	return __kernfs_iattrs(kn, 1);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  67) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  68) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  69) static struct kernfs_iattrs *kernfs_iattrs_noalloc(struct kernfs_node *kn)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  70) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  71) 	return __kernfs_iattrs(kn, 0);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  72) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  73) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  74) int __kernfs_setattr(struct kernfs_node *kn, const struct iattr *iattr)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  75) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  76) 	struct kernfs_iattrs *attrs;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  77) 	unsigned int ia_valid = iattr->ia_valid;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  78) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  79) 	attrs = kernfs_iattrs(kn);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  80) 	if (!attrs)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  81) 		return -ENOMEM;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  82) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  83) 	if (ia_valid & ATTR_UID)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  84) 		attrs->ia_uid = iattr->ia_uid;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  85) 	if (ia_valid & ATTR_GID)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  86) 		attrs->ia_gid = iattr->ia_gid;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  87) 	if (ia_valid & ATTR_ATIME)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  88) 		attrs->ia_atime = iattr->ia_atime;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  89) 	if (ia_valid & ATTR_MTIME)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  90) 		attrs->ia_mtime = iattr->ia_mtime;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  91) 	if (ia_valid & ATTR_CTIME)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  92) 		attrs->ia_ctime = iattr->ia_ctime;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  93) 	if (ia_valid & ATTR_MODE)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  94) 		kn->mode = iattr->ia_mode;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  95) 	return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  96) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  97) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  98) /**
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  99)  * kernfs_setattr - set iattr on a node
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 100)  * @kn: target node
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 101)  * @iattr: iattr to set
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 102)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 103)  * Returns 0 on success, -errno on failure.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 104)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 105) int kernfs_setattr(struct kernfs_node *kn, const struct iattr *iattr)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 106) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 107) 	int ret;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 108) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 109) 	mutex_lock(&kernfs_mutex);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 110) 	ret = __kernfs_setattr(kn, iattr);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 111) 	mutex_unlock(&kernfs_mutex);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 112) 	return ret;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 113) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 114) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 115) int kernfs_iop_setattr(struct dentry *dentry, struct iattr *iattr)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 116) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 117) 	struct inode *inode = d_inode(dentry);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 118) 	struct kernfs_node *kn = inode->i_private;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 119) 	int error;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 120) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 121) 	if (!kn)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 122) 		return -EINVAL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 123) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 124) 	mutex_lock(&kernfs_mutex);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 125) 	error = setattr_prepare(dentry, iattr);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 126) 	if (error)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 127) 		goto out;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 128) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 129) 	error = __kernfs_setattr(kn, iattr);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 130) 	if (error)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 131) 		goto out;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 132) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 133) 	/* this ignores size changes */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 134) 	setattr_copy(inode, iattr);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 135) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 136) out:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 137) 	mutex_unlock(&kernfs_mutex);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 138) 	return error;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 139) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 140) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 141) ssize_t kernfs_iop_listxattr(struct dentry *dentry, char *buf, size_t size)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 142) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 143) 	struct kernfs_node *kn = kernfs_dentry_node(dentry);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 144) 	struct kernfs_iattrs *attrs;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 145) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 146) 	attrs = kernfs_iattrs(kn);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 147) 	if (!attrs)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 148) 		return -ENOMEM;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 149) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 150) 	return simple_xattr_list(d_inode(dentry), &attrs->xattrs, buf, size);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 151) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 152) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 153) static inline void set_default_inode_attr(struct inode *inode, umode_t mode)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 154) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 155) 	inode->i_mode = mode;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 156) 	inode->i_atime = inode->i_mtime =
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 157) 		inode->i_ctime = current_time(inode);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 158) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 159) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 160) static inline void set_inode_attr(struct inode *inode,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 161) 				  struct kernfs_iattrs *attrs)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 162) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 163) 	inode->i_uid = attrs->ia_uid;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 164) 	inode->i_gid = attrs->ia_gid;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 165) 	inode->i_atime = attrs->ia_atime;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 166) 	inode->i_mtime = attrs->ia_mtime;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 167) 	inode->i_ctime = attrs->ia_ctime;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 168) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 169) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 170) static void kernfs_refresh_inode(struct kernfs_node *kn, struct inode *inode)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 171) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 172) 	struct kernfs_iattrs *attrs = kn->iattr;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 173) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 174) 	inode->i_mode = kn->mode;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 175) 	if (attrs)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 176) 		/*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 177) 		 * kernfs_node has non-default attributes get them from
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 178) 		 * persistent copy in kernfs_node.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 179) 		 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 180) 		set_inode_attr(inode, attrs);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 181) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 182) 	if (kernfs_type(kn) == KERNFS_DIR)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 183) 		set_nlink(inode, kn->dir.subdirs + 2);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 184) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 185) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 186) int kernfs_iop_getattr(const struct path *path, struct kstat *stat,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 187) 		       u32 request_mask, unsigned int query_flags)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 188) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 189) 	struct inode *inode = d_inode(path->dentry);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 190) 	struct kernfs_node *kn = inode->i_private;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 191) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 192) 	mutex_lock(&kernfs_mutex);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 193) 	kernfs_refresh_inode(kn, inode);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 194) 	mutex_unlock(&kernfs_mutex);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 195) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 196) 	generic_fillattr(inode, stat);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 197) 	return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 198) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 199) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 200) static void kernfs_init_inode(struct kernfs_node *kn, struct inode *inode)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 201) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 202) 	kernfs_get(kn);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 203) 	inode->i_private = kn;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 204) 	inode->i_mapping->a_ops = &kernfs_aops;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 205) 	inode->i_op = &kernfs_iops;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 206) 	inode->i_generation = kernfs_gen(kn);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 207) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 208) 	set_default_inode_attr(inode, kn->mode);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 209) 	kernfs_refresh_inode(kn, inode);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 210) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 211) 	/* initialize inode according to type */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 212) 	switch (kernfs_type(kn)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 213) 	case KERNFS_DIR:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 214) 		inode->i_op = &kernfs_dir_iops;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 215) 		inode->i_fop = &kernfs_dir_fops;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 216) 		if (kn->flags & KERNFS_EMPTY_DIR)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 217) 			make_empty_dir_inode(inode);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 218) 		break;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 219) 	case KERNFS_FILE:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 220) 		inode->i_size = kn->attr.size;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 221) 		inode->i_fop = &kernfs_file_fops;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 222) 		break;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 223) 	case KERNFS_LINK:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 224) 		inode->i_op = &kernfs_symlink_iops;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 225) 		break;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 226) 	default:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 227) 		BUG();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 228) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 229) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 230) 	unlock_new_inode(inode);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 231) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 232) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 233) /**
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 234)  *	kernfs_get_inode - get inode for kernfs_node
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 235)  *	@sb: super block
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 236)  *	@kn: kernfs_node to allocate inode for
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 237)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 238)  *	Get inode for @kn.  If such inode doesn't exist, a new inode is
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 239)  *	allocated and basics are initialized.  New inode is returned
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 240)  *	locked.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 241)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 242)  *	LOCKING:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 243)  *	Kernel thread context (may sleep).
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 244)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 245)  *	RETURNS:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 246)  *	Pointer to allocated inode on success, NULL on failure.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 247)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 248) struct inode *kernfs_get_inode(struct super_block *sb, struct kernfs_node *kn)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 249) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 250) 	struct inode *inode;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 251) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 252) 	inode = iget_locked(sb, kernfs_ino(kn));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 253) 	if (inode && (inode->i_state & I_NEW))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 254) 		kernfs_init_inode(kn, inode);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 255) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 256) 	return inode;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 257) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 258) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 259) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 260)  * The kernfs_node serves as both an inode and a directory entry for
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 261)  * kernfs.  To prevent the kernfs inode numbers from being freed
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 262)  * prematurely we take a reference to kernfs_node from the kernfs inode.  A
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 263)  * super_operations.evict_inode() implementation is needed to drop that
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 264)  * reference upon inode destruction.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 265)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 266) void kernfs_evict_inode(struct inode *inode)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 267) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 268) 	struct kernfs_node *kn = inode->i_private;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 269) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 270) 	truncate_inode_pages_final(&inode->i_data);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 271) 	clear_inode(inode);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 272) 	kernfs_put(kn);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 273) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 274) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 275) int kernfs_iop_permission(struct inode *inode, int mask)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 276) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 277) 	struct kernfs_node *kn;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 278) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 279) 	if (mask & MAY_NOT_BLOCK)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 280) 		return -ECHILD;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 281) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 282) 	kn = inode->i_private;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 283) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 284) 	mutex_lock(&kernfs_mutex);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 285) 	kernfs_refresh_inode(kn, inode);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 286) 	mutex_unlock(&kernfs_mutex);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 287) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 288) 	return generic_permission(inode, mask);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 289) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 290) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 291) int kernfs_xattr_get(struct kernfs_node *kn, const char *name,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 292) 		     void *value, size_t size)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 293) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 294) 	struct kernfs_iattrs *attrs = kernfs_iattrs_noalloc(kn);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 295) 	if (!attrs)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 296) 		return -ENODATA;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 297) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 298) 	return simple_xattr_get(&attrs->xattrs, name, value, size);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 299) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 300) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 301) int kernfs_xattr_set(struct kernfs_node *kn, const char *name,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 302) 		     const void *value, size_t size, int flags)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 303) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 304) 	struct kernfs_iattrs *attrs = kernfs_iattrs(kn);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 305) 	if (!attrs)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 306) 		return -ENOMEM;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 307) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 308) 	return simple_xattr_set(&attrs->xattrs, name, value, size, flags, NULL);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 309) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 310) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 311) static int kernfs_vfs_xattr_get(const struct xattr_handler *handler,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 312) 				struct dentry *unused, struct inode *inode,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 313) 				const char *suffix, void *value, size_t size,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 314) 				int flags)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 315) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 316) 	const char *name = xattr_full_name(handler, suffix);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 317) 	struct kernfs_node *kn = inode->i_private;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 318) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 319) 	return kernfs_xattr_get(kn, name, value, size);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 320) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 321) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 322) static int kernfs_vfs_xattr_set(const struct xattr_handler *handler,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 323) 				struct dentry *unused, struct inode *inode,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 324) 				const char *suffix, const void *value,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 325) 				size_t size, int flags)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 326) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 327) 	const char *name = xattr_full_name(handler, suffix);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 328) 	struct kernfs_node *kn = inode->i_private;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 329) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 330) 	return kernfs_xattr_set(kn, name, value, size, flags);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 331) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 332) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 333) static int kernfs_vfs_user_xattr_add(struct kernfs_node *kn,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 334) 				     const char *full_name,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 335) 				     struct simple_xattrs *xattrs,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 336) 				     const void *value, size_t size, int flags)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 337) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 338) 	atomic_t *sz = &kn->iattr->user_xattr_size;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 339) 	atomic_t *nr = &kn->iattr->nr_user_xattrs;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 340) 	ssize_t removed_size;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 341) 	int ret;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 342) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 343) 	if (atomic_inc_return(nr) > KERNFS_MAX_USER_XATTRS) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 344) 		ret = -ENOSPC;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 345) 		goto dec_count_out;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 346) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 347) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 348) 	if (atomic_add_return(size, sz) > KERNFS_USER_XATTR_SIZE_LIMIT) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 349) 		ret = -ENOSPC;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 350) 		goto dec_size_out;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 351) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 352) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 353) 	ret = simple_xattr_set(xattrs, full_name, value, size, flags,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 354) 			       &removed_size);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 355) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 356) 	if (!ret && removed_size >= 0)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 357) 		size = removed_size;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 358) 	else if (!ret)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 359) 		return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 360) dec_size_out:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 361) 	atomic_sub(size, sz);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 362) dec_count_out:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 363) 	atomic_dec(nr);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 364) 	return ret;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 365) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 366) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 367) static int kernfs_vfs_user_xattr_rm(struct kernfs_node *kn,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 368) 				    const char *full_name,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 369) 				    struct simple_xattrs *xattrs,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 370) 				    const void *value, size_t size, int flags)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 371) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 372) 	atomic_t *sz = &kn->iattr->user_xattr_size;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 373) 	atomic_t *nr = &kn->iattr->nr_user_xattrs;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 374) 	ssize_t removed_size;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 375) 	int ret;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 376) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 377) 	ret = simple_xattr_set(xattrs, full_name, value, size, flags,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 378) 			       &removed_size);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 379) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 380) 	if (removed_size >= 0) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 381) 		atomic_sub(removed_size, sz);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 382) 		atomic_dec(nr);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 383) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 384) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 385) 	return ret;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 386) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 387) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 388) static int kernfs_vfs_user_xattr_set(const struct xattr_handler *handler,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 389) 				     struct dentry *unused, struct inode *inode,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 390) 				     const char *suffix, const void *value,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 391) 				     size_t size, int flags)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 392) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 393) 	const char *full_name = xattr_full_name(handler, suffix);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 394) 	struct kernfs_node *kn = inode->i_private;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 395) 	struct kernfs_iattrs *attrs;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 396) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 397) 	if (!(kernfs_root(kn)->flags & KERNFS_ROOT_SUPPORT_USER_XATTR))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 398) 		return -EOPNOTSUPP;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 399) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 400) 	attrs = kernfs_iattrs(kn);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 401) 	if (!attrs)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 402) 		return -ENOMEM;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 403) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 404) 	if (value)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 405) 		return kernfs_vfs_user_xattr_add(kn, full_name, &attrs->xattrs,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 406) 						 value, size, flags);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 407) 	else
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 408) 		return kernfs_vfs_user_xattr_rm(kn, full_name, &attrs->xattrs,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 409) 						value, size, flags);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 410) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 411) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 412) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 413) static const struct xattr_handler kernfs_trusted_xattr_handler = {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 414) 	.prefix = XATTR_TRUSTED_PREFIX,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 415) 	.get = kernfs_vfs_xattr_get,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 416) 	.set = kernfs_vfs_xattr_set,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 417) };
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 418) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 419) static const struct xattr_handler kernfs_security_xattr_handler = {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 420) 	.prefix = XATTR_SECURITY_PREFIX,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 421) 	.get = kernfs_vfs_xattr_get,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 422) 	.set = kernfs_vfs_xattr_set,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 423) };
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 424) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 425) static const struct xattr_handler kernfs_user_xattr_handler = {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 426) 	.prefix = XATTR_USER_PREFIX,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 427) 	.get = kernfs_vfs_xattr_get,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 428) 	.set = kernfs_vfs_user_xattr_set,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 429) };
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 430) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 431) const struct xattr_handler *kernfs_xattr_handlers[] = {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 432) 	&kernfs_trusted_xattr_handler,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 433) 	&kernfs_security_xattr_handler,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 434) 	&kernfs_user_xattr_handler,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 435) 	NULL
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 436) };