ia64/linux-2.6.18-xen.hg

view fs/configfs/inode.c @ 524:7f8b544237bf

netfront: Allow netfront in domain 0.

This is useful if your physical network device is in a utility domain.

Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
author Keir Fraser <keir.fraser@citrix.com>
date Tue Apr 15 15:18:58 2008 +0100 (2008-04-15)
parents 831230e53067
children
line source
1 /* -*- mode: c; c-basic-offset: 8; -*-
2 * vim: noexpandtab sw=8 ts=8 sts=0:
3 *
4 * inode.c - basic inode and dentry operations.
5 *
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public
8 * License as published by the Free Software Foundation; either
9 * version 2 of the License, or (at your option) any later version.
10 *
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 * General Public License for more details.
15 *
16 * You should have received a copy of the GNU General Public
17 * License along with this program; if not, write to the
18 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
19 * Boston, MA 021110-1307, USA.
20 *
21 * Based on sysfs:
22 * sysfs is Copyright (C) 2001, 2002, 2003 Patrick Mochel
23 *
24 * configfs Copyright (C) 2005 Oracle. All rights reserved.
25 *
26 * Please see Documentation/filesystems/configfs.txt for more information.
27 */
29 #undef DEBUG
31 #include <linux/pagemap.h>
32 #include <linux/namei.h>
33 #include <linux/backing-dev.h>
34 #include <linux/capability.h>
36 #include <linux/configfs.h>
37 #include "configfs_internal.h"
39 extern struct super_block * configfs_sb;
41 static const struct address_space_operations configfs_aops = {
42 .readpage = simple_readpage,
43 .prepare_write = simple_prepare_write,
44 .commit_write = simple_commit_write
45 };
47 static struct backing_dev_info configfs_backing_dev_info = {
48 .ra_pages = 0, /* No readahead */
49 .capabilities = BDI_CAP_NO_ACCT_DIRTY | BDI_CAP_NO_WRITEBACK,
50 };
52 static struct inode_operations configfs_inode_operations ={
53 .setattr = configfs_setattr,
54 };
56 int configfs_setattr(struct dentry * dentry, struct iattr * iattr)
57 {
58 struct inode * inode = dentry->d_inode;
59 struct configfs_dirent * sd = dentry->d_fsdata;
60 struct iattr * sd_iattr;
61 unsigned int ia_valid = iattr->ia_valid;
62 int error;
64 if (!sd)
65 return -EINVAL;
67 sd_iattr = sd->s_iattr;
69 error = inode_change_ok(inode, iattr);
70 if (error)
71 return error;
73 error = inode_setattr(inode, iattr);
74 if (error)
75 return error;
77 if (!sd_iattr) {
78 /* setting attributes for the first time, allocate now */
79 sd_iattr = kmalloc(sizeof(struct iattr), GFP_KERNEL);
80 if (!sd_iattr)
81 return -ENOMEM;
82 /* assign default attributes */
83 memset(sd_iattr, 0, sizeof(struct iattr));
84 sd_iattr->ia_mode = sd->s_mode;
85 sd_iattr->ia_uid = 0;
86 sd_iattr->ia_gid = 0;
87 sd_iattr->ia_atime = sd_iattr->ia_mtime = sd_iattr->ia_ctime = CURRENT_TIME;
88 sd->s_iattr = sd_iattr;
89 }
91 /* attributes were changed atleast once in past */
93 if (ia_valid & ATTR_UID)
94 sd_iattr->ia_uid = iattr->ia_uid;
95 if (ia_valid & ATTR_GID)
96 sd_iattr->ia_gid = iattr->ia_gid;
97 if (ia_valid & ATTR_ATIME)
98 sd_iattr->ia_atime = timespec_trunc(iattr->ia_atime,
99 inode->i_sb->s_time_gran);
100 if (ia_valid & ATTR_MTIME)
101 sd_iattr->ia_mtime = timespec_trunc(iattr->ia_mtime,
102 inode->i_sb->s_time_gran);
103 if (ia_valid & ATTR_CTIME)
104 sd_iattr->ia_ctime = timespec_trunc(iattr->ia_ctime,
105 inode->i_sb->s_time_gran);
106 if (ia_valid & ATTR_MODE) {
107 umode_t mode = iattr->ia_mode;
109 if (!in_group_p(inode->i_gid) && !capable(CAP_FSETID))
110 mode &= ~S_ISGID;
111 sd_iattr->ia_mode = sd->s_mode = mode;
112 }
114 return error;
115 }
117 static inline void set_default_inode_attr(struct inode * inode, mode_t mode)
118 {
119 inode->i_mode = mode;
120 inode->i_uid = 0;
121 inode->i_gid = 0;
122 inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
123 }
125 static inline void set_inode_attr(struct inode * inode, struct iattr * iattr)
126 {
127 inode->i_mode = iattr->ia_mode;
128 inode->i_uid = iattr->ia_uid;
129 inode->i_gid = iattr->ia_gid;
130 inode->i_atime = iattr->ia_atime;
131 inode->i_mtime = iattr->ia_mtime;
132 inode->i_ctime = iattr->ia_ctime;
133 }
135 struct inode * configfs_new_inode(mode_t mode, struct configfs_dirent * sd)
136 {
137 struct inode * inode = new_inode(configfs_sb);
138 if (inode) {
139 inode->i_blksize = PAGE_CACHE_SIZE;
140 inode->i_blocks = 0;
141 inode->i_mapping->a_ops = &configfs_aops;
142 inode->i_mapping->backing_dev_info = &configfs_backing_dev_info;
143 inode->i_op = &configfs_inode_operations;
145 if (sd->s_iattr) {
146 /* sysfs_dirent has non-default attributes
147 * get them for the new inode from persistent copy
148 * in sysfs_dirent
149 */
150 set_inode_attr(inode, sd->s_iattr);
151 } else
152 set_default_inode_attr(inode, mode);
153 }
154 return inode;
155 }
157 int configfs_create(struct dentry * dentry, int mode, int (*init)(struct inode *))
158 {
159 int error = 0;
160 struct inode * inode = NULL;
161 if (dentry) {
162 if (!dentry->d_inode) {
163 struct configfs_dirent *sd = dentry->d_fsdata;
164 if ((inode = configfs_new_inode(mode, sd))) {
165 if (dentry->d_parent && dentry->d_parent->d_inode) {
166 struct inode *p_inode = dentry->d_parent->d_inode;
167 p_inode->i_mtime = p_inode->i_ctime = CURRENT_TIME;
168 }
169 goto Proceed;
170 }
171 else
172 error = -ENOMEM;
173 } else
174 error = -EEXIST;
175 } else
176 error = -ENOENT;
177 goto Done;
179 Proceed:
180 if (init)
181 error = init(inode);
182 if (!error) {
183 d_instantiate(dentry, inode);
184 if (S_ISDIR(mode) || S_ISLNK(mode))
185 dget(dentry); /* pin link and directory dentries in core */
186 } else
187 iput(inode);
188 Done:
189 return error;
190 }
192 /*
193 * Get the name for corresponding element represented by the given configfs_dirent
194 */
195 const unsigned char * configfs_get_name(struct configfs_dirent *sd)
196 {
197 struct configfs_attribute *attr;
199 BUG_ON(!sd || !sd->s_element);
201 /* These always have a dentry, so use that */
202 if (sd->s_type & (CONFIGFS_DIR | CONFIGFS_ITEM_LINK))
203 return sd->s_dentry->d_name.name;
205 if (sd->s_type & CONFIGFS_ITEM_ATTR) {
206 attr = sd->s_element;
207 return attr->ca_name;
208 }
209 return NULL;
210 }
213 /*
214 * Unhashes the dentry corresponding to given configfs_dirent
215 * Called with parent inode's i_mutex held.
216 */
217 void configfs_drop_dentry(struct configfs_dirent * sd, struct dentry * parent)
218 {
219 struct dentry * dentry = sd->s_dentry;
221 if (dentry) {
222 spin_lock(&dcache_lock);
223 spin_lock(&dentry->d_lock);
224 if (!(d_unhashed(dentry) && dentry->d_inode)) {
225 dget_locked(dentry);
226 __d_drop(dentry);
227 spin_unlock(&dentry->d_lock);
228 spin_unlock(&dcache_lock);
229 simple_unlink(parent->d_inode, dentry);
230 } else {
231 spin_unlock(&dentry->d_lock);
232 spin_unlock(&dcache_lock);
233 }
234 }
235 }
237 void configfs_hash_and_remove(struct dentry * dir, const char * name)
238 {
239 struct configfs_dirent * sd;
240 struct configfs_dirent * parent_sd = dir->d_fsdata;
242 if (dir->d_inode == NULL)
243 /* no inode means this hasn't been made visible yet */
244 return;
246 mutex_lock(&dir->d_inode->i_mutex);
247 list_for_each_entry(sd, &parent_sd->s_children, s_sibling) {
248 if (!sd->s_element)
249 continue;
250 if (!strcmp(configfs_get_name(sd), name)) {
251 list_del_init(&sd->s_sibling);
252 configfs_drop_dentry(sd, dir);
253 configfs_put(sd);
254 break;
255 }
256 }
257 mutex_unlock(&dir->d_inode->i_mutex);
258 }