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![Tejun Heo](/assets/img/avatar_default.png)
kernfs has just been separated out from sysfs and we're already in full conflict mode. Nothing can make the situation any worse. Let's take the chance to name things properly. This patch performs the following renames. * s/sysfs_open_dirent/kernfs_open_node/ * s/sysfs_open_file/kernfs_open_file/ * s/sysfs_inode_attrs/kernfs_iattrs/ * s/sysfs_addrm_cxt/kernfs_addrm_cxt/ * s/sysfs_super_info/kernfs_super_info/ * s/sysfs_info()/kernfs_info()/ * s/sysfs_open_dirent_lock/kernfs_open_node_lock/ * s/sysfs_open_file_mutex/kernfs_open_file_mutex/ * s/sysfs_of()/kernfs_of()/ This patch is strictly rename only and doesn't introduce any functional difference. Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
377 lines
8.7 KiB
C
377 lines
8.7 KiB
C
/*
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* fs/kernfs/inode.c - kernfs inode implementation
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*
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* Copyright (c) 2001-3 Patrick Mochel
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* Copyright (c) 2007 SUSE Linux Products GmbH
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* Copyright (c) 2007, 2013 Tejun Heo <tj@kernel.org>
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*
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* This file is released under the GPLv2.
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*/
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#include <linux/pagemap.h>
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#include <linux/backing-dev.h>
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#include <linux/capability.h>
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#include <linux/errno.h>
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#include <linux/slab.h>
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#include <linux/xattr.h>
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#include <linux/security.h>
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#include "kernfs-internal.h"
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static const struct address_space_operations sysfs_aops = {
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.readpage = simple_readpage,
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.write_begin = simple_write_begin,
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.write_end = simple_write_end,
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};
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static struct backing_dev_info sysfs_backing_dev_info = {
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.name = "sysfs",
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.ra_pages = 0, /* No readahead */
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.capabilities = BDI_CAP_NO_ACCT_AND_WRITEBACK,
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};
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static const struct inode_operations sysfs_inode_operations = {
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.permission = sysfs_permission,
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.setattr = sysfs_setattr,
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.getattr = sysfs_getattr,
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.setxattr = sysfs_setxattr,
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.removexattr = sysfs_removexattr,
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.getxattr = sysfs_getxattr,
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.listxattr = sysfs_listxattr,
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};
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void __init sysfs_inode_init(void)
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{
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if (bdi_init(&sysfs_backing_dev_info))
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panic("failed to init sysfs_backing_dev_info");
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}
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static struct kernfs_iattrs *kernfs_iattrs(struct kernfs_node *kn)
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{
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struct iattr *iattrs;
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if (kn->iattr)
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return kn->iattr;
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kn->iattr = kzalloc(sizeof(struct kernfs_iattrs), GFP_KERNEL);
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if (!kn->iattr)
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return NULL;
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iattrs = &kn->iattr->ia_iattr;
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/* assign default attributes */
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iattrs->ia_mode = kn->mode;
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iattrs->ia_uid = GLOBAL_ROOT_UID;
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iattrs->ia_gid = GLOBAL_ROOT_GID;
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iattrs->ia_atime = iattrs->ia_mtime = iattrs->ia_ctime = CURRENT_TIME;
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simple_xattrs_init(&kn->iattr->xattrs);
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return kn->iattr;
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}
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static int __kernfs_setattr(struct kernfs_node *kn, const struct iattr *iattr)
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{
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struct kernfs_iattrs *attrs;
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struct iattr *iattrs;
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unsigned int ia_valid = iattr->ia_valid;
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attrs = kernfs_iattrs(kn);
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if (!attrs)
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return -ENOMEM;
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iattrs = &attrs->ia_iattr;
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if (ia_valid & ATTR_UID)
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iattrs->ia_uid = iattr->ia_uid;
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if (ia_valid & ATTR_GID)
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iattrs->ia_gid = iattr->ia_gid;
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if (ia_valid & ATTR_ATIME)
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iattrs->ia_atime = iattr->ia_atime;
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if (ia_valid & ATTR_MTIME)
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iattrs->ia_mtime = iattr->ia_mtime;
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if (ia_valid & ATTR_CTIME)
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iattrs->ia_ctime = iattr->ia_ctime;
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if (ia_valid & ATTR_MODE) {
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umode_t mode = iattr->ia_mode;
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iattrs->ia_mode = kn->mode = mode;
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}
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return 0;
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}
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/**
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* kernfs_setattr - set iattr on a node
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* @kn: target node
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* @iattr: iattr to set
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*
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* Returns 0 on success, -errno on failure.
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*/
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int kernfs_setattr(struct kernfs_node *kn, const struct iattr *iattr)
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{
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int ret;
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mutex_lock(&sysfs_mutex);
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ret = __kernfs_setattr(kn, iattr);
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mutex_unlock(&sysfs_mutex);
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return ret;
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}
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int sysfs_setattr(struct dentry *dentry, struct iattr *iattr)
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{
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struct inode *inode = dentry->d_inode;
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struct kernfs_node *kn = dentry->d_fsdata;
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int error;
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if (!kn)
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return -EINVAL;
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mutex_lock(&sysfs_mutex);
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error = inode_change_ok(inode, iattr);
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if (error)
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goto out;
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error = __kernfs_setattr(kn, iattr);
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if (error)
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goto out;
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/* this ignores size changes */
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setattr_copy(inode, iattr);
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out:
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mutex_unlock(&sysfs_mutex);
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return error;
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}
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static int sysfs_sd_setsecdata(struct kernfs_node *kn, void **secdata,
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u32 *secdata_len)
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{
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struct kernfs_iattrs *attrs;
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void *old_secdata;
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size_t old_secdata_len;
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attrs = kernfs_iattrs(kn);
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if (!attrs)
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return -ENOMEM;
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old_secdata = attrs->ia_secdata;
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old_secdata_len = attrs->ia_secdata_len;
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attrs->ia_secdata = *secdata;
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attrs->ia_secdata_len = *secdata_len;
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*secdata = old_secdata;
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*secdata_len = old_secdata_len;
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return 0;
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}
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int sysfs_setxattr(struct dentry *dentry, const char *name, const void *value,
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size_t size, int flags)
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{
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struct kernfs_node *kn = dentry->d_fsdata;
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struct kernfs_iattrs *attrs;
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void *secdata;
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int error;
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u32 secdata_len = 0;
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attrs = kernfs_iattrs(kn);
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if (!attrs)
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return -ENOMEM;
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if (!strncmp(name, XATTR_SECURITY_PREFIX, XATTR_SECURITY_PREFIX_LEN)) {
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const char *suffix = name + XATTR_SECURITY_PREFIX_LEN;
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error = security_inode_setsecurity(dentry->d_inode, suffix,
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value, size, flags);
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if (error)
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return error;
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error = security_inode_getsecctx(dentry->d_inode,
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&secdata, &secdata_len);
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if (error)
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return error;
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mutex_lock(&sysfs_mutex);
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error = sysfs_sd_setsecdata(kn, &secdata, &secdata_len);
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mutex_unlock(&sysfs_mutex);
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if (secdata)
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security_release_secctx(secdata, secdata_len);
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return error;
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} else if (!strncmp(name, XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN)) {
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return simple_xattr_set(&attrs->xattrs, name, value, size,
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flags);
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}
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return -EINVAL;
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}
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int sysfs_removexattr(struct dentry *dentry, const char *name)
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{
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struct kernfs_node *kn = dentry->d_fsdata;
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struct kernfs_iattrs *attrs;
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attrs = kernfs_iattrs(kn);
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if (!attrs)
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return -ENOMEM;
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return simple_xattr_remove(&attrs->xattrs, name);
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}
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ssize_t sysfs_getxattr(struct dentry *dentry, const char *name, void *buf,
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size_t size)
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{
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struct kernfs_node *kn = dentry->d_fsdata;
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struct kernfs_iattrs *attrs;
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attrs = kernfs_iattrs(kn);
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if (!attrs)
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return -ENOMEM;
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return simple_xattr_get(&attrs->xattrs, name, buf, size);
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}
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ssize_t sysfs_listxattr(struct dentry *dentry, char *buf, size_t size)
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{
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struct kernfs_node *kn = dentry->d_fsdata;
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struct kernfs_iattrs *attrs;
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attrs = kernfs_iattrs(kn);
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if (!attrs)
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return -ENOMEM;
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return simple_xattr_list(&attrs->xattrs, buf, size);
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}
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static inline void set_default_inode_attr(struct inode *inode, umode_t mode)
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{
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inode->i_mode = mode;
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inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
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}
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static inline void set_inode_attr(struct inode *inode, struct iattr *iattr)
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{
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inode->i_uid = iattr->ia_uid;
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inode->i_gid = iattr->ia_gid;
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inode->i_atime = iattr->ia_atime;
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inode->i_mtime = iattr->ia_mtime;
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inode->i_ctime = iattr->ia_ctime;
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}
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static void sysfs_refresh_inode(struct kernfs_node *kn, struct inode *inode)
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{
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struct kernfs_iattrs *attrs = kn->iattr;
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inode->i_mode = kn->mode;
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if (attrs) {
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/*
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* kernfs_node has non-default attributes get them from
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* persistent copy in kernfs_node.
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*/
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set_inode_attr(inode, &attrs->ia_iattr);
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security_inode_notifysecctx(inode, attrs->ia_secdata,
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attrs->ia_secdata_len);
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}
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if (sysfs_type(kn) == SYSFS_DIR)
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set_nlink(inode, kn->dir.subdirs + 2);
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}
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int sysfs_getattr(struct vfsmount *mnt, struct dentry *dentry,
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struct kstat *stat)
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{
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struct kernfs_node *kn = dentry->d_fsdata;
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struct inode *inode = dentry->d_inode;
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mutex_lock(&sysfs_mutex);
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sysfs_refresh_inode(kn, inode);
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mutex_unlock(&sysfs_mutex);
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generic_fillattr(inode, stat);
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return 0;
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}
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static void sysfs_init_inode(struct kernfs_node *kn, struct inode *inode)
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{
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kernfs_get(kn);
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inode->i_private = kn;
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inode->i_mapping->a_ops = &sysfs_aops;
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inode->i_mapping->backing_dev_info = &sysfs_backing_dev_info;
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inode->i_op = &sysfs_inode_operations;
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set_default_inode_attr(inode, kn->mode);
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sysfs_refresh_inode(kn, inode);
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/* initialize inode according to type */
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switch (sysfs_type(kn)) {
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case SYSFS_DIR:
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inode->i_op = &sysfs_dir_inode_operations;
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inode->i_fop = &sysfs_dir_operations;
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break;
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case SYSFS_KOBJ_ATTR:
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inode->i_size = kn->attr.size;
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inode->i_fop = &kernfs_file_operations;
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break;
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case SYSFS_KOBJ_LINK:
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inode->i_op = &sysfs_symlink_inode_operations;
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break;
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default:
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BUG();
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}
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unlock_new_inode(inode);
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}
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/**
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* sysfs_get_inode - get inode for kernfs_node
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* @sb: super block
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* @kn: kernfs_node to allocate inode for
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*
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* Get inode for @kn. If such inode doesn't exist, a new inode is
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* allocated and basics are initialized. New inode is returned
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* locked.
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*
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* LOCKING:
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* Kernel thread context (may sleep).
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*
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* RETURNS:
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* Pointer to allocated inode on success, NULL on failure.
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*/
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struct inode *sysfs_get_inode(struct super_block *sb, struct kernfs_node *kn)
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{
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struct inode *inode;
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inode = iget_locked(sb, kn->ino);
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if (inode && (inode->i_state & I_NEW))
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sysfs_init_inode(kn, inode);
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return inode;
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}
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/*
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* The kernfs_node serves as both an inode and a directory entry for sysfs.
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* To prevent the sysfs inode numbers from being freed prematurely we take
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* a reference to kernfs_node from the sysfs inode. A
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* super_operations.evict_inode() implementation is needed to drop that
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* reference upon inode destruction.
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*/
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void sysfs_evict_inode(struct inode *inode)
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{
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struct kernfs_node *kn = inode->i_private;
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truncate_inode_pages(&inode->i_data, 0);
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clear_inode(inode);
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kernfs_put(kn);
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}
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int sysfs_permission(struct inode *inode, int mask)
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{
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struct kernfs_node *kn;
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if (mask & MAY_NOT_BLOCK)
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return -ECHILD;
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kn = inode->i_private;
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mutex_lock(&sysfs_mutex);
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sysfs_refresh_inode(kn, inode);
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mutex_unlock(&sysfs_mutex);
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return generic_permission(inode, mask);
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}
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