blob: cf78d44a8d6a8bcff1a546e3606058de97e90722 [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>
Louis Rillinge74cc062009-01-28 19:18:32 +010036#include <linux/lockdep.h>
Tejun Heo5a0e3ad2010-03-24 17:04:11 +090037#include <linux/slab.h>
Joel Becker7063fbf2005-12-15 14:29:43 -080038
39#include <linux/configfs.h>
40#include "configfs_internal.h"
41
Louis Rillinge74cc062009-01-28 19:18:32 +010042#ifdef CONFIG_LOCKDEP
43static struct lock_class_key default_group_class[MAX_LOCK_DEPTH];
44#endif
45
Joel Becker7063fbf2005-12-15 14:29:43 -080046extern struct super_block * configfs_sb;
47
Christoph Hellwigf5e54d62006-06-28 04:26:44 -070048static const struct address_space_operations configfs_aops = {
Joel Becker7063fbf2005-12-15 14:29:43 -080049 .readpage = simple_readpage,
Nick Piggin800d15a2007-10-16 01:25:03 -070050 .write_begin = simple_write_begin,
51 .write_end = simple_write_end,
Joel Becker7063fbf2005-12-15 14:29:43 -080052};
53
54static struct backing_dev_info configfs_backing_dev_info = {
Jens Axboed9938312009-06-12 14:45:52 +020055 .name = "configfs",
Joel Becker7063fbf2005-12-15 14:29:43 -080056 .ra_pages = 0, /* No readahead */
Miklos Szeredie4ad08f2008-04-30 00:54:37 -070057 .capabilities = BDI_CAP_NO_ACCT_AND_WRITEBACK,
Joel Becker7063fbf2005-12-15 14:29:43 -080058};
59
Arjan van de Ven754661f2007-02-12 00:55:38 -080060static const struct inode_operations configfs_inode_operations ={
Joel Becker3d0f89b2006-01-25 13:31:07 -080061 .setattr = configfs_setattr,
62};
63
64int configfs_setattr(struct dentry * dentry, struct iattr * iattr)
65{
66 struct inode * inode = dentry->d_inode;
67 struct configfs_dirent * sd = dentry->d_fsdata;
68 struct iattr * sd_iattr;
69 unsigned int ia_valid = iattr->ia_valid;
70 int error;
71
72 if (!sd)
73 return -EINVAL;
74
75 sd_iattr = sd->s_iattr;
Joel Becker3d0f89b2006-01-25 13:31:07 -080076 if (!sd_iattr) {
77 /* setting attributes for the first time, allocate now */
Panagiotis Issarisf8314dc2006-09-27 01:49:37 -070078 sd_iattr = kzalloc(sizeof(struct iattr), GFP_KERNEL);
Joel Becker3d0f89b2006-01-25 13:31:07 -080079 if (!sd_iattr)
80 return -ENOMEM;
81 /* assign default attributes */
Joel Becker3d0f89b2006-01-25 13:31:07 -080082 sd_iattr->ia_mode = sd->s_mode;
83 sd_iattr->ia_uid = 0;
84 sd_iattr->ia_gid = 0;
85 sd_iattr->ia_atime = sd_iattr->ia_mtime = sd_iattr->ia_ctime = CURRENT_TIME;
86 sd->s_iattr = sd_iattr;
87 }
Joel Becker3d0f89b2006-01-25 13:31:07 -080088 /* attributes were changed atleast once in past */
89
Nick Piggin75de46b2010-05-31 17:58:02 +100090 error = simple_setattr(dentry, iattr);
91 if (error)
92 return error;
93
Joel Becker3d0f89b2006-01-25 13:31:07 -080094 if (ia_valid & ATTR_UID)
95 sd_iattr->ia_uid = iattr->ia_uid;
96 if (ia_valid & ATTR_GID)
97 sd_iattr->ia_gid = iattr->ia_gid;
98 if (ia_valid & ATTR_ATIME)
99 sd_iattr->ia_atime = timespec_trunc(iattr->ia_atime,
100 inode->i_sb->s_time_gran);
101 if (ia_valid & ATTR_MTIME)
102 sd_iattr->ia_mtime = timespec_trunc(iattr->ia_mtime,
103 inode->i_sb->s_time_gran);
104 if (ia_valid & ATTR_CTIME)
105 sd_iattr->ia_ctime = timespec_trunc(iattr->ia_ctime,
106 inode->i_sb->s_time_gran);
107 if (ia_valid & ATTR_MODE) {
108 umode_t mode = iattr->ia_mode;
109
110 if (!in_group_p(inode->i_gid) && !capable(CAP_FSETID))
111 mode &= ~S_ISGID;
112 sd_iattr->ia_mode = sd->s_mode = mode;
113 }
114
115 return error;
116}
117
118static inline void set_default_inode_attr(struct inode * inode, mode_t mode)
119{
120 inode->i_mode = mode;
Joel Becker3d0f89b2006-01-25 13:31:07 -0800121 inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
122}
123
124static inline void set_inode_attr(struct inode * inode, struct iattr * iattr)
125{
126 inode->i_mode = iattr->ia_mode;
127 inode->i_uid = iattr->ia_uid;
128 inode->i_gid = iattr->ia_gid;
129 inode->i_atime = iattr->ia_atime;
130 inode->i_mtime = iattr->ia_mtime;
131 inode->i_ctime = iattr->ia_ctime;
132}
133
134struct inode * configfs_new_inode(mode_t mode, struct configfs_dirent * sd)
Joel Becker7063fbf2005-12-15 14:29:43 -0800135{
136 struct inode * inode = new_inode(configfs_sb);
137 if (inode) {
Joel Becker7063fbf2005-12-15 14:29:43 -0800138 inode->i_mapping->a_ops = &configfs_aops;
139 inode->i_mapping->backing_dev_info = &configfs_backing_dev_info;
Joel Becker3d0f89b2006-01-25 13:31:07 -0800140 inode->i_op = &configfs_inode_operations;
141
142 if (sd->s_iattr) {
143 /* sysfs_dirent has non-default attributes
144 * get them for the new inode from persistent copy
145 * in sysfs_dirent
146 */
147 set_inode_attr(inode, sd->s_iattr);
148 } else
149 set_default_inode_attr(inode, mode);
Joel Becker7063fbf2005-12-15 14:29:43 -0800150 }
151 return inode;
152}
153
Louis Rillinge74cc062009-01-28 19:18:32 +0100154#ifdef CONFIG_LOCKDEP
155
156static void configfs_set_inode_lock_class(struct configfs_dirent *sd,
157 struct inode *inode)
158{
159 int depth = sd->s_depth;
160
161 if (depth > 0) {
162 if (depth <= ARRAY_SIZE(default_group_class)) {
163 lockdep_set_class(&inode->i_mutex,
164 &default_group_class[depth - 1]);
165 } else {
166 /*
167 * In practice the maximum level of locking depth is
168 * already reached. Just inform about possible reasons.
169 */
170 printk(KERN_INFO "configfs: Too many levels of inodes"
171 " for the locking correctness validator.\n");
172 printk(KERN_INFO "Spurious warnings may appear.\n");
173 }
174 }
175}
176
177#else /* CONFIG_LOCKDEP */
178
179static void configfs_set_inode_lock_class(struct configfs_dirent *sd,
180 struct inode *inode)
181{
182}
183
184#endif /* CONFIG_LOCKDEP */
185
Joel Becker7063fbf2005-12-15 14:29:43 -0800186int configfs_create(struct dentry * dentry, int mode, int (*init)(struct inode *))
187{
188 int error = 0;
189 struct inode * inode = NULL;
190 if (dentry) {
191 if (!dentry->d_inode) {
Joel Becker3d0f89b2006-01-25 13:31:07 -0800192 struct configfs_dirent *sd = dentry->d_fsdata;
193 if ((inode = configfs_new_inode(mode, sd))) {
Joel Becker7063fbf2005-12-15 14:29:43 -0800194 if (dentry->d_parent && dentry->d_parent->d_inode) {
195 struct inode *p_inode = dentry->d_parent->d_inode;
196 p_inode->i_mtime = p_inode->i_ctime = CURRENT_TIME;
197 }
Louis Rillinge74cc062009-01-28 19:18:32 +0100198 configfs_set_inode_lock_class(sd, inode);
Joel Becker7063fbf2005-12-15 14:29:43 -0800199 goto Proceed;
200 }
201 else
202 error = -ENOMEM;
203 } else
204 error = -EEXIST;
205 } else
206 error = -ENOENT;
207 goto Done;
208
209 Proceed:
210 if (init)
211 error = init(inode);
212 if (!error) {
213 d_instantiate(dentry, inode);
214 if (S_ISDIR(mode) || S_ISLNK(mode))
215 dget(dentry); /* pin link and directory dentries in core */
216 } else
217 iput(inode);
218 Done:
219 return error;
220}
221
222/*
223 * Get the name for corresponding element represented by the given configfs_dirent
224 */
225const unsigned char * configfs_get_name(struct configfs_dirent *sd)
226{
Joel Becker3d0f89b2006-01-25 13:31:07 -0800227 struct configfs_attribute *attr;
Joel Becker7063fbf2005-12-15 14:29:43 -0800228
Eric Sesterhenn / snakebyte1a1974f2006-01-27 10:32:24 +0100229 BUG_ON(!sd || !sd->s_element);
Joel Becker7063fbf2005-12-15 14:29:43 -0800230
231 /* These always have a dentry, so use that */
232 if (sd->s_type & (CONFIGFS_DIR | CONFIGFS_ITEM_LINK))
233 return sd->s_dentry->d_name.name;
234
235 if (sd->s_type & CONFIGFS_ITEM_ATTR) {
236 attr = sd->s_element;
Joel Becker3d0f89b2006-01-25 13:31:07 -0800237 return attr->ca_name;
Joel Becker7063fbf2005-12-15 14:29:43 -0800238 }
239 return NULL;
240}
241
242
243/*
244 * Unhashes the dentry corresponding to given configfs_dirent
Jes Sorensen1b1dcc12006-01-09 15:59:24 -0800245 * Called with parent inode's i_mutex held.
Joel Becker7063fbf2005-12-15 14:29:43 -0800246 */
247void configfs_drop_dentry(struct configfs_dirent * sd, struct dentry * parent)
248{
249 struct dentry * dentry = sd->s_dentry;
250
251 if (dentry) {
252 spin_lock(&dcache_lock);
Joel Becker3d0f89b2006-01-25 13:31:07 -0800253 spin_lock(&dentry->d_lock);
Joel Becker7063fbf2005-12-15 14:29:43 -0800254 if (!(d_unhashed(dentry) && dentry->d_inode)) {
255 dget_locked(dentry);
256 __d_drop(dentry);
Joel Becker3d0f89b2006-01-25 13:31:07 -0800257 spin_unlock(&dentry->d_lock);
Joel Becker7063fbf2005-12-15 14:29:43 -0800258 spin_unlock(&dcache_lock);
259 simple_unlink(parent->d_inode, dentry);
Joel Becker3d0f89b2006-01-25 13:31:07 -0800260 } else {
261 spin_unlock(&dentry->d_lock);
Joel Becker7063fbf2005-12-15 14:29:43 -0800262 spin_unlock(&dcache_lock);
Joel Becker3d0f89b2006-01-25 13:31:07 -0800263 }
Joel Becker7063fbf2005-12-15 14:29:43 -0800264 }
265}
266
267void configfs_hash_and_remove(struct dentry * dir, const char * name)
268{
269 struct configfs_dirent * sd;
270 struct configfs_dirent * parent_sd = dir->d_fsdata;
271
Joel Becker3d0f89b2006-01-25 13:31:07 -0800272 if (dir->d_inode == NULL)
273 /* no inode means this hasn't been made visible yet */
274 return;
275
Jes Sorensen1b1dcc12006-01-09 15:59:24 -0800276 mutex_lock(&dir->d_inode->i_mutex);
Joel Becker7063fbf2005-12-15 14:29:43 -0800277 list_for_each_entry(sd, &parent_sd->s_children, s_sibling) {
278 if (!sd->s_element)
279 continue;
280 if (!strcmp(configfs_get_name(sd), name)) {
Louis Rilling6f610762008-06-16 19:00:58 +0200281 spin_lock(&configfs_dirent_lock);
Joel Becker7063fbf2005-12-15 14:29:43 -0800282 list_del_init(&sd->s_sibling);
Louis Rilling6f610762008-06-16 19:00:58 +0200283 spin_unlock(&configfs_dirent_lock);
Joel Becker7063fbf2005-12-15 14:29:43 -0800284 configfs_drop_dentry(sd, dir);
285 configfs_put(sd);
286 break;
287 }
288 }
Jes Sorensen1b1dcc12006-01-09 15:59:24 -0800289 mutex_unlock(&dir->d_inode->i_mutex);
Joel Becker7063fbf2005-12-15 14:29:43 -0800290}
291
Peter Zijlstrae0bf68d2007-10-16 23:25:46 -0700292int __init configfs_inode_init(void)
293{
294 return bdi_init(&configfs_backing_dev_info);
295}
Joel Becker7063fbf2005-12-15 14:29:43 -0800296
Peter Zijlstrae0bf68d2007-10-16 23:25:46 -0700297void __exit configfs_inode_exit(void)
298{
299 bdi_destroy(&configfs_backing_dev_info);
300}