blob: ddc003a9d2143937d2c493196319a11570c79dcb [file] [log] [blame]
Joel Becker7063fbf2005-12-15 14:29:43 -08001/* -*- 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 */
28
29#undef DEBUG
30
31#include <linux/pagemap.h>
32#include <linux/namei.h>
33#include <linux/backing-dev.h>
Joel Becker3d0f89b2006-01-25 13:31:07 -080034#include <linux/capability.h>
Alexey Dobriyane8edc6e2007-05-21 01:22:52 +040035#include <linux/sched.h>
Joel Becker7063fbf2005-12-15 14:29:43 -080036
37#include <linux/configfs.h>
38#include "configfs_internal.h"
39
40extern struct super_block * configfs_sb;
41
Christoph Hellwigf5e54d62006-06-28 04:26:44 -070042static const struct address_space_operations configfs_aops = {
Joel Becker7063fbf2005-12-15 14:29:43 -080043 .readpage = simple_readpage,
44 .prepare_write = simple_prepare_write,
45 .commit_write = simple_commit_write
46};
47
48static struct backing_dev_info configfs_backing_dev_info = {
49 .ra_pages = 0, /* No readahead */
50 .capabilities = BDI_CAP_NO_ACCT_DIRTY | BDI_CAP_NO_WRITEBACK,
51};
52
Arjan van de Ven754661f2007-02-12 00:55:38 -080053static const struct inode_operations configfs_inode_operations ={
Joel Becker3d0f89b2006-01-25 13:31:07 -080054 .setattr = configfs_setattr,
55};
56
57int configfs_setattr(struct dentry * dentry, struct iattr * iattr)
58{
59 struct inode * inode = dentry->d_inode;
60 struct configfs_dirent * sd = dentry->d_fsdata;
61 struct iattr * sd_iattr;
62 unsigned int ia_valid = iattr->ia_valid;
63 int error;
64
65 if (!sd)
66 return -EINVAL;
67
68 sd_iattr = sd->s_iattr;
69
70 error = inode_change_ok(inode, iattr);
71 if (error)
72 return error;
73
74 error = inode_setattr(inode, iattr);
75 if (error)
76 return error;
77
78 if (!sd_iattr) {
79 /* setting attributes for the first time, allocate now */
Panagiotis Issarisf8314dc2006-09-27 01:49:37 -070080 sd_iattr = kzalloc(sizeof(struct iattr), GFP_KERNEL);
Joel Becker3d0f89b2006-01-25 13:31:07 -080081 if (!sd_iattr)
82 return -ENOMEM;
83 /* assign default attributes */
Joel Becker3d0f89b2006-01-25 13:31:07 -080084 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 }
90
91 /* attributes were changed atleast once in past */
92
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;
108
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 }
113
114 return error;
115}
116
117static 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}
124
125static 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}
134
135struct inode * configfs_new_inode(mode_t mode, struct configfs_dirent * sd)
Joel Becker7063fbf2005-12-15 14:29:43 -0800136{
137 struct inode * inode = new_inode(configfs_sb);
138 if (inode) {
Joel Becker7063fbf2005-12-15 14:29:43 -0800139 inode->i_blocks = 0;
Joel Becker7063fbf2005-12-15 14:29:43 -0800140 inode->i_mapping->a_ops = &configfs_aops;
141 inode->i_mapping->backing_dev_info = &configfs_backing_dev_info;
Joel Becker3d0f89b2006-01-25 13:31:07 -0800142 inode->i_op = &configfs_inode_operations;
143
144 if (sd->s_iattr) {
145 /* sysfs_dirent has non-default attributes
146 * get them for the new inode from persistent copy
147 * in sysfs_dirent
148 */
149 set_inode_attr(inode, sd->s_iattr);
150 } else
151 set_default_inode_attr(inode, mode);
Joel Becker7063fbf2005-12-15 14:29:43 -0800152 }
153 return inode;
154}
155
156int configfs_create(struct dentry * dentry, int mode, int (*init)(struct inode *))
157{
158 int error = 0;
159 struct inode * inode = NULL;
160 if (dentry) {
161 if (!dentry->d_inode) {
Joel Becker3d0f89b2006-01-25 13:31:07 -0800162 struct configfs_dirent *sd = dentry->d_fsdata;
163 if ((inode = configfs_new_inode(mode, sd))) {
Joel Becker7063fbf2005-12-15 14:29:43 -0800164 if (dentry->d_parent && dentry->d_parent->d_inode) {
165 struct inode *p_inode = dentry->d_parent->d_inode;
166 p_inode->i_mtime = p_inode->i_ctime = CURRENT_TIME;
167 }
168 goto Proceed;
169 }
170 else
171 error = -ENOMEM;
172 } else
173 error = -EEXIST;
174 } else
175 error = -ENOENT;
176 goto Done;
177
178 Proceed:
179 if (init)
180 error = init(inode);
181 if (!error) {
182 d_instantiate(dentry, inode);
183 if (S_ISDIR(mode) || S_ISLNK(mode))
184 dget(dentry); /* pin link and directory dentries in core */
185 } else
186 iput(inode);
187 Done:
188 return error;
189}
190
191/*
192 * Get the name for corresponding element represented by the given configfs_dirent
193 */
194const unsigned char * configfs_get_name(struct configfs_dirent *sd)
195{
Joel Becker3d0f89b2006-01-25 13:31:07 -0800196 struct configfs_attribute *attr;
Joel Becker7063fbf2005-12-15 14:29:43 -0800197
Eric Sesterhenn / snakebyte1a1974f2006-01-27 10:32:24 +0100198 BUG_ON(!sd || !sd->s_element);
Joel Becker7063fbf2005-12-15 14:29:43 -0800199
200 /* These always have a dentry, so use that */
201 if (sd->s_type & (CONFIGFS_DIR | CONFIGFS_ITEM_LINK))
202 return sd->s_dentry->d_name.name;
203
204 if (sd->s_type & CONFIGFS_ITEM_ATTR) {
205 attr = sd->s_element;
Joel Becker3d0f89b2006-01-25 13:31:07 -0800206 return attr->ca_name;
Joel Becker7063fbf2005-12-15 14:29:43 -0800207 }
208 return NULL;
209}
210
211
212/*
213 * Unhashes the dentry corresponding to given configfs_dirent
Jes Sorensen1b1dcc12006-01-09 15:59:24 -0800214 * Called with parent inode's i_mutex held.
Joel Becker7063fbf2005-12-15 14:29:43 -0800215 */
216void configfs_drop_dentry(struct configfs_dirent * sd, struct dentry * parent)
217{
218 struct dentry * dentry = sd->s_dentry;
219
220 if (dentry) {
221 spin_lock(&dcache_lock);
Joel Becker3d0f89b2006-01-25 13:31:07 -0800222 spin_lock(&dentry->d_lock);
Joel Becker7063fbf2005-12-15 14:29:43 -0800223 if (!(d_unhashed(dentry) && dentry->d_inode)) {
224 dget_locked(dentry);
225 __d_drop(dentry);
Joel Becker3d0f89b2006-01-25 13:31:07 -0800226 spin_unlock(&dentry->d_lock);
Joel Becker7063fbf2005-12-15 14:29:43 -0800227 spin_unlock(&dcache_lock);
228 simple_unlink(parent->d_inode, dentry);
Joel Becker3d0f89b2006-01-25 13:31:07 -0800229 } else {
230 spin_unlock(&dentry->d_lock);
Joel Becker7063fbf2005-12-15 14:29:43 -0800231 spin_unlock(&dcache_lock);
Joel Becker3d0f89b2006-01-25 13:31:07 -0800232 }
Joel Becker7063fbf2005-12-15 14:29:43 -0800233 }
234}
235
236void configfs_hash_and_remove(struct dentry * dir, const char * name)
237{
238 struct configfs_dirent * sd;
239 struct configfs_dirent * parent_sd = dir->d_fsdata;
240
Joel Becker3d0f89b2006-01-25 13:31:07 -0800241 if (dir->d_inode == NULL)
242 /* no inode means this hasn't been made visible yet */
243 return;
244
Jes Sorensen1b1dcc12006-01-09 15:59:24 -0800245 mutex_lock(&dir->d_inode->i_mutex);
Joel Becker7063fbf2005-12-15 14:29:43 -0800246 list_for_each_entry(sd, &parent_sd->s_children, s_sibling) {
247 if (!sd->s_element)
248 continue;
249 if (!strcmp(configfs_get_name(sd), name)) {
250 list_del_init(&sd->s_sibling);
251 configfs_drop_dentry(sd, dir);
252 configfs_put(sd);
253 break;
254 }
255 }
Jes Sorensen1b1dcc12006-01-09 15:59:24 -0800256 mutex_unlock(&dir->d_inode->i_mutex);
Joel Becker7063fbf2005-12-15 14:29:43 -0800257}
258
259