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/configfs.txt for more 27 * information. 28 */ 29 30 #undef DEBUG 31 32 #include <linux/pagemap.h> 33 #include <linux/namei.h> 34 #include <linux/backing-dev.h> 35 #include <linux/capability.h> 36 #include <linux/sched.h> 37 #include <linux/lockdep.h> 38 #include <linux/slab.h> 39 40 #include <linux/configfs.h> 41 #include "configfs_internal.h" 42 43 #ifdef CONFIG_LOCKDEP 44 static struct lock_class_key default_group_class[MAX_LOCK_DEPTH]; 45 #endif 46 47 static const struct address_space_operations configfs_aops = { 48 .readpage = simple_readpage, 49 .write_begin = simple_write_begin, 50 .write_end = simple_write_end, 51 }; 52 53 static const struct inode_operations configfs_inode_operations ={ 54 .setattr = configfs_setattr, 55 }; 56 57 int configfs_setattr(struct dentry * dentry, struct iattr * iattr) 58 { 59 struct inode * inode = d_inode(dentry); 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 if (!sd_iattr) { 70 /* setting attributes for the first time, allocate now */ 71 sd_iattr = kzalloc(sizeof(struct iattr), GFP_KERNEL); 72 if (!sd_iattr) 73 return -ENOMEM; 74 /* assign default attributes */ 75 sd_iattr->ia_mode = sd->s_mode; 76 sd_iattr->ia_uid = GLOBAL_ROOT_UID; 77 sd_iattr->ia_gid = GLOBAL_ROOT_GID; 78 sd_iattr->ia_atime = sd_iattr->ia_mtime = 79 sd_iattr->ia_ctime = current_time(inode); 80 sd->s_iattr = sd_iattr; 81 } 82 /* attributes were changed atleast once in past */ 83 84 error = simple_setattr(dentry, iattr); 85 if (error) 86 return error; 87 88 if (ia_valid & ATTR_UID) 89 sd_iattr->ia_uid = iattr->ia_uid; 90 if (ia_valid & ATTR_GID) 91 sd_iattr->ia_gid = iattr->ia_gid; 92 if (ia_valid & ATTR_ATIME) 93 sd_iattr->ia_atime = timespec_trunc(iattr->ia_atime, 94 inode->i_sb->s_time_gran); 95 if (ia_valid & ATTR_MTIME) 96 sd_iattr->ia_mtime = timespec_trunc(iattr->ia_mtime, 97 inode->i_sb->s_time_gran); 98 if (ia_valid & ATTR_CTIME) 99 sd_iattr->ia_ctime = timespec_trunc(iattr->ia_ctime, 100 inode->i_sb->s_time_gran); 101 if (ia_valid & ATTR_MODE) { 102 umode_t mode = iattr->ia_mode; 103 104 if (!in_group_p(inode->i_gid) && !capable(CAP_FSETID)) 105 mode &= ~S_ISGID; 106 sd_iattr->ia_mode = sd->s_mode = mode; 107 } 108 109 return error; 110 } 111 112 static inline void set_default_inode_attr(struct inode * inode, umode_t mode) 113 { 114 inode->i_mode = mode; 115 inode->i_atime = inode->i_mtime = 116 inode->i_ctime = current_time(inode); 117 } 118 119 static inline void set_inode_attr(struct inode * inode, struct iattr * iattr) 120 { 121 inode->i_mode = iattr->ia_mode; 122 inode->i_uid = iattr->ia_uid; 123 inode->i_gid = iattr->ia_gid; 124 inode->i_atime = iattr->ia_atime; 125 inode->i_mtime = iattr->ia_mtime; 126 inode->i_ctime = iattr->ia_ctime; 127 } 128 129 struct inode *configfs_new_inode(umode_t mode, struct configfs_dirent *sd, 130 struct super_block *s) 131 { 132 struct inode * inode = new_inode(s); 133 if (inode) { 134 inode->i_ino = get_next_ino(); 135 inode->i_mapping->a_ops = &configfs_aops; 136 inode->i_op = &configfs_inode_operations; 137 138 if (sd->s_iattr) { 139 /* sysfs_dirent has non-default attributes 140 * get them for the new inode from persistent copy 141 * in sysfs_dirent 142 */ 143 set_inode_attr(inode, sd->s_iattr); 144 } else 145 set_default_inode_attr(inode, mode); 146 } 147 return inode; 148 } 149 150 #ifdef CONFIG_LOCKDEP 151 152 static void configfs_set_inode_lock_class(struct configfs_dirent *sd, 153 struct inode *inode) 154 { 155 int depth = sd->s_depth; 156 157 if (depth > 0) { 158 if (depth <= ARRAY_SIZE(default_group_class)) { 159 lockdep_set_class(&inode->i_rwsem, 160 &default_group_class[depth - 1]); 161 } else { 162 /* 163 * In practice the maximum level of locking depth is 164 * already reached. Just inform about possible reasons. 165 */ 166 pr_info("Too many levels of inodes for the locking correctness validator.\n"); 167 pr_info("Spurious warnings may appear.\n"); 168 } 169 } 170 } 171 172 #else /* CONFIG_LOCKDEP */ 173 174 static void configfs_set_inode_lock_class(struct configfs_dirent *sd, 175 struct inode *inode) 176 { 177 } 178 179 #endif /* CONFIG_LOCKDEP */ 180 181 int configfs_create(struct dentry * dentry, umode_t mode, void (*init)(struct inode *)) 182 { 183 int error = 0; 184 struct inode *inode = NULL; 185 struct configfs_dirent *sd; 186 struct inode *p_inode; 187 188 if (!dentry) 189 return -ENOENT; 190 191 if (d_really_is_positive(dentry)) 192 return -EEXIST; 193 194 sd = dentry->d_fsdata; 195 inode = configfs_new_inode(mode, sd, dentry->d_sb); 196 if (!inode) 197 return -ENOMEM; 198 199 p_inode = d_inode(dentry->d_parent); 200 p_inode->i_mtime = p_inode->i_ctime = current_time(p_inode); 201 configfs_set_inode_lock_class(sd, inode); 202 203 init(inode); 204 if (S_ISDIR(mode) || S_ISLNK(mode)) { 205 /* 206 * ->symlink(), ->mkdir(), configfs_register_subsystem() or 207 * create_default_group() - already hashed. 208 */ 209 d_instantiate(dentry, inode); 210 dget(dentry); /* pin link and directory dentries in core */ 211 } else { 212 /* ->lookup() */ 213 d_add(dentry, inode); 214 } 215 return error; 216 } 217 218 /* 219 * Get the name for corresponding element represented by the given configfs_dirent 220 */ 221 const unsigned char * configfs_get_name(struct configfs_dirent *sd) 222 { 223 struct configfs_attribute *attr; 224 225 BUG_ON(!sd || !sd->s_element); 226 227 /* These always have a dentry, so use that */ 228 if (sd->s_type & (CONFIGFS_DIR | CONFIGFS_ITEM_LINK)) 229 return sd->s_dentry->d_name.name; 230 231 if (sd->s_type & (CONFIGFS_ITEM_ATTR | CONFIGFS_ITEM_BIN_ATTR)) { 232 attr = sd->s_element; 233 return attr->ca_name; 234 } 235 return NULL; 236 } 237 238 239 /* 240 * Unhashes the dentry corresponding to given configfs_dirent 241 * Called with parent inode's i_mutex held. 242 */ 243 void configfs_drop_dentry(struct configfs_dirent * sd, struct dentry * parent) 244 { 245 struct dentry * dentry = sd->s_dentry; 246 247 if (dentry) { 248 spin_lock(&dentry->d_lock); 249 if (simple_positive(dentry)) { 250 dget_dlock(dentry); 251 __d_drop(dentry); 252 spin_unlock(&dentry->d_lock); 253 simple_unlink(d_inode(parent), dentry); 254 } else 255 spin_unlock(&dentry->d_lock); 256 } 257 } 258 259 void configfs_hash_and_remove(struct dentry * dir, const char * name) 260 { 261 struct configfs_dirent * sd; 262 struct configfs_dirent * parent_sd = dir->d_fsdata; 263 264 if (d_really_is_negative(dir)) 265 /* no inode means this hasn't been made visible yet */ 266 return; 267 268 inode_lock(d_inode(dir)); 269 list_for_each_entry(sd, &parent_sd->s_children, s_sibling) { 270 if (!sd->s_element) 271 continue; 272 if (!strcmp(configfs_get_name(sd), name)) { 273 spin_lock(&configfs_dirent_lock); 274 list_del_init(&sd->s_sibling); 275 spin_unlock(&configfs_dirent_lock); 276 configfs_drop_dentry(sd, dir); 277 configfs_put(sd); 278 break; 279 } 280 } 281 inode_unlock(d_inode(dir)); 282 } 283