1/* 2 * linux/fs/sysv/namei.c 3 * 4 * minix/namei.c 5 * Copyright (C) 1991, 1992 Linus Torvalds 6 * 7 * coh/namei.c 8 * Copyright (C) 1993 Pascal Haible, Bruno Haible 9 * 10 * sysv/namei.c 11 * Copyright (C) 1993 Bruno Haible 12 * Copyright (C) 1997, 1998 Krzysztof G. Baranowski 13 */ 14 15#include <linux/pagemap.h> 16#include "sysv.h" 17 18static int add_nondir(struct dentry *dentry, struct inode *inode) 19{ 20 int err = sysv_add_link(dentry, inode); 21 if (!err) { 22 d_instantiate(dentry, inode); 23 return 0; 24 } 25 inode_dec_link_count(inode); 26 iput(inode); 27 return err; 28} 29 30static int sysv_hash(struct dentry *dentry, struct qstr *qstr) 31{ 32 /* Truncate the name in place, avoids having to define a compare 33 function. */ 34 if (qstr->len > SYSV_NAMELEN) { 35 qstr->len = SYSV_NAMELEN; 36 qstr->hash = full_name_hash(qstr->name, qstr->len); 37 } 38 return 0; 39} 40 41struct dentry_operations sysv_dentry_operations = { 42 .d_hash = sysv_hash, 43}; 44 45static struct dentry *sysv_lookup(struct inode * dir, struct dentry * dentry, struct nameidata *nd) 46{ 47 struct inode * inode = NULL; 48 ino_t ino; 49 50 dentry->d_op = dir->i_sb->s_root->d_op; 51 if (dentry->d_name.len > SYSV_NAMELEN) 52 return ERR_PTR(-ENAMETOOLONG); 53 ino = sysv_inode_by_name(dentry); 54 55 if (ino) { 56 inode = iget(dir->i_sb, ino); 57 if (!inode) 58 return ERR_PTR(-EACCES); 59 } 60 d_add(dentry, inode); 61 return NULL; 62} 63 64static int sysv_mknod(struct inode * dir, struct dentry * dentry, int mode, dev_t rdev) 65{ 66 struct inode * inode; 67 int err; 68 69 if (!old_valid_dev(rdev)) 70 return -EINVAL; 71 72 inode = sysv_new_inode(dir, mode); 73 err = PTR_ERR(inode); 74 75 if (!IS_ERR(inode)) { 76 sysv_set_inode(inode, rdev); 77 mark_inode_dirty(inode); 78 err = add_nondir(dentry, inode); 79 } 80 return err; 81} 82 83static int sysv_create(struct inode * dir, struct dentry * dentry, int mode, struct nameidata *nd) 84{ 85 return sysv_mknod(dir, dentry, mode, 0); 86} 87 88static int sysv_symlink(struct inode * dir, struct dentry * dentry, 89 const char * symname) 90{ 91 int err = -ENAMETOOLONG; 92 int l = strlen(symname)+1; 93 struct inode * inode; 94 95 if (l > dir->i_sb->s_blocksize) 96 goto out; 97 98 inode = sysv_new_inode(dir, S_IFLNK|0777); 99 err = PTR_ERR(inode); 100 if (IS_ERR(inode)) 101 goto out; 102 103 sysv_set_inode(inode, 0); 104 err = page_symlink(inode, symname, l); 105 if (err) 106 goto out_fail; 107 108 mark_inode_dirty(inode); 109 err = add_nondir(dentry, inode); 110out: 111 return err; 112 113out_fail: 114 inode_dec_link_count(inode); 115 iput(inode); 116 goto out; 117} 118 119static int sysv_link(struct dentry * old_dentry, struct inode * dir, 120 struct dentry * dentry) 121{ 122 struct inode *inode = old_dentry->d_inode; 123 124 if (inode->i_nlink >= SYSV_SB(inode->i_sb)->s_link_max) 125 return -EMLINK; 126 127 inode->i_ctime = CURRENT_TIME_SEC; 128 inode_inc_link_count(inode); 129 atomic_inc(&inode->i_count); 130 131 return add_nondir(dentry, inode); 132} 133 134static int sysv_mkdir(struct inode * dir, struct dentry *dentry, int mode) 135{ 136 struct inode * inode; 137 int err = -EMLINK; 138 139 if (dir->i_nlink >= SYSV_SB(dir->i_sb)->s_link_max) 140 goto out; 141 inode_inc_link_count(dir); 142 143 inode = sysv_new_inode(dir, S_IFDIR|mode); 144 err = PTR_ERR(inode); 145 if (IS_ERR(inode)) 146 goto out_dir; 147 148 sysv_set_inode(inode, 0); 149 150 inode_inc_link_count(inode); 151 152 err = sysv_make_empty(inode, dir); 153 if (err) 154 goto out_fail; 155 156 err = sysv_add_link(dentry, inode); 157 if (err) 158 goto out_fail; 159 160 d_instantiate(dentry, inode); 161out: 162 return err; 163 164out_fail: 165 inode_dec_link_count(inode); 166 inode_dec_link_count(inode); 167 iput(inode); 168out_dir: 169 inode_dec_link_count(dir); 170 goto out; 171} 172 173static int sysv_unlink(struct inode * dir, struct dentry * dentry) 174{ 175 struct inode * inode = dentry->d_inode; 176 struct page * page; 177 struct sysv_dir_entry * de; 178 int err = -ENOENT; 179 180 de = sysv_find_entry(dentry, &page); 181 if (!de) 182 goto out; 183 184 err = sysv_delete_entry (de, page); 185 if (err) 186 goto out; 187 188 inode->i_ctime = dir->i_ctime; 189 inode_dec_link_count(inode); 190out: 191 return err; 192} 193 194static int sysv_rmdir(struct inode * dir, struct dentry * dentry) 195{ 196 struct inode *inode = dentry->d_inode; 197 int err = -ENOTEMPTY; 198 199 if (sysv_empty_dir(inode)) { 200 err = sysv_unlink(dir, dentry); 201 if (!err) { 202 inode->i_size = 0; 203 inode_dec_link_count(inode); 204 inode_dec_link_count(dir); 205 } 206 } 207 return err; 208} 209 210/* 211 * Anybody can rename anything with this: the permission checks are left to the 212 * higher-level routines. 213 */ 214static int sysv_rename(struct inode * old_dir, struct dentry * old_dentry, 215 struct inode * new_dir, struct dentry * new_dentry) 216{ 217 struct inode * old_inode = old_dentry->d_inode; 218 struct inode * new_inode = new_dentry->d_inode; 219 struct page * dir_page = NULL; 220 struct sysv_dir_entry * dir_de = NULL; 221 struct page * old_page; 222 struct sysv_dir_entry * old_de; 223 int err = -ENOENT; 224 225 old_de = sysv_find_entry(old_dentry, &old_page); 226 if (!old_de) 227 goto out; 228 229 if (S_ISDIR(old_inode->i_mode)) { 230 err = -EIO; 231 dir_de = sysv_dotdot(old_inode, &dir_page); 232 if (!dir_de) 233 goto out_old; 234 } 235 236 if (new_inode) { 237 struct page * new_page; 238 struct sysv_dir_entry * new_de; 239 240 err = -ENOTEMPTY; 241 if (dir_de && !sysv_empty_dir(new_inode)) 242 goto out_dir; 243 244 err = -ENOENT; 245 new_de = sysv_find_entry(new_dentry, &new_page); 246 if (!new_de) 247 goto out_dir; 248 inode_inc_link_count(old_inode); 249 sysv_set_link(new_de, new_page, old_inode); 250 new_inode->i_ctime = CURRENT_TIME_SEC; 251 if (dir_de) 252 drop_nlink(new_inode); 253 inode_dec_link_count(new_inode); 254 } else { 255 if (dir_de) { 256 err = -EMLINK; 257 if (new_dir->i_nlink >= SYSV_SB(new_dir->i_sb)->s_link_max) 258 goto out_dir; 259 } 260 inode_inc_link_count(old_inode); 261 err = sysv_add_link(new_dentry, old_inode); 262 if (err) { 263 inode_dec_link_count(old_inode); 264 goto out_dir; 265 } 266 if (dir_de) 267 inode_inc_link_count(new_dir); 268 } 269 270 sysv_delete_entry(old_de, old_page); 271 inode_dec_link_count(old_inode); 272 273 if (dir_de) { 274 sysv_set_link(dir_de, dir_page, new_dir); 275 inode_dec_link_count(old_dir); 276 } 277 return 0; 278 279out_dir: 280 if (dir_de) { 281 kunmap(dir_page); 282 page_cache_release(dir_page); 283 } 284out_old: 285 kunmap(old_page); 286 page_cache_release(old_page); 287out: 288 return err; 289} 290 291/* 292 * directories can handle most operations... 293 */ 294const struct inode_operations sysv_dir_inode_operations = { 295 .create = sysv_create, 296 .lookup = sysv_lookup, 297 .link = sysv_link, 298 .unlink = sysv_unlink, 299 .symlink = sysv_symlink, 300 .mkdir = sysv_mkdir, 301 .rmdir = sysv_rmdir, 302 .mknod = sysv_mknod, 303 .rename = sysv_rename, 304 .getattr = sysv_getattr, 305}; 306