namei.c revision 8de52778798fe39660a8d6b26f290e0c93202761
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(const struct dentry *dentry, const struct inode *inode, 31 struct qstr *qstr) 32{ 33 /* Truncate the name in place, avoids having to define a compare 34 function. */ 35 if (qstr->len > SYSV_NAMELEN) { 36 qstr->len = SYSV_NAMELEN; 37 qstr->hash = full_name_hash(qstr->name, qstr->len); 38 } 39 return 0; 40} 41 42const struct dentry_operations sysv_dentry_operations = { 43 .d_hash = sysv_hash, 44}; 45 46static struct dentry *sysv_lookup(struct inode * dir, struct dentry * dentry, struct nameidata *nd) 47{ 48 struct inode * inode = NULL; 49 ino_t ino; 50 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 = sysv_iget(dir->i_sb, ino); 57 if (IS_ERR(inode)) 58 return ERR_CAST(inode); 59 } 60 d_add(dentry, inode); 61 return NULL; 62} 63 64static int sysv_mknod(struct inode * dir, struct dentry * dentry, umode_t 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, umode_t 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 inode->i_ctime = CURRENT_TIME_SEC; 125 inode_inc_link_count(inode); 126 ihold(inode); 127 128 return add_nondir(dentry, inode); 129} 130 131static int sysv_mkdir(struct inode * dir, struct dentry *dentry, umode_t mode) 132{ 133 struct inode * inode; 134 int err; 135 136 inode_inc_link_count(dir); 137 138 inode = sysv_new_inode(dir, S_IFDIR|mode); 139 err = PTR_ERR(inode); 140 if (IS_ERR(inode)) 141 goto out_dir; 142 143 sysv_set_inode(inode, 0); 144 145 inode_inc_link_count(inode); 146 147 err = sysv_make_empty(inode, dir); 148 if (err) 149 goto out_fail; 150 151 err = sysv_add_link(dentry, inode); 152 if (err) 153 goto out_fail; 154 155 d_instantiate(dentry, inode); 156out: 157 return err; 158 159out_fail: 160 inode_dec_link_count(inode); 161 inode_dec_link_count(inode); 162 iput(inode); 163out_dir: 164 inode_dec_link_count(dir); 165 goto out; 166} 167 168static int sysv_unlink(struct inode * dir, struct dentry * dentry) 169{ 170 struct inode * inode = dentry->d_inode; 171 struct page * page; 172 struct sysv_dir_entry * de; 173 int err = -ENOENT; 174 175 de = sysv_find_entry(dentry, &page); 176 if (!de) 177 goto out; 178 179 err = sysv_delete_entry (de, page); 180 if (err) 181 goto out; 182 183 inode->i_ctime = dir->i_ctime; 184 inode_dec_link_count(inode); 185out: 186 return err; 187} 188 189static int sysv_rmdir(struct inode * dir, struct dentry * dentry) 190{ 191 struct inode *inode = dentry->d_inode; 192 int err = -ENOTEMPTY; 193 194 if (sysv_empty_dir(inode)) { 195 err = sysv_unlink(dir, dentry); 196 if (!err) { 197 inode->i_size = 0; 198 inode_dec_link_count(inode); 199 inode_dec_link_count(dir); 200 } 201 } 202 return err; 203} 204 205/* 206 * Anybody can rename anything with this: the permission checks are left to the 207 * higher-level routines. 208 */ 209static int sysv_rename(struct inode * old_dir, struct dentry * old_dentry, 210 struct inode * new_dir, struct dentry * new_dentry) 211{ 212 struct inode * old_inode = old_dentry->d_inode; 213 struct inode * new_inode = new_dentry->d_inode; 214 struct page * dir_page = NULL; 215 struct sysv_dir_entry * dir_de = NULL; 216 struct page * old_page; 217 struct sysv_dir_entry * old_de; 218 int err = -ENOENT; 219 220 old_de = sysv_find_entry(old_dentry, &old_page); 221 if (!old_de) 222 goto out; 223 224 if (S_ISDIR(old_inode->i_mode)) { 225 err = -EIO; 226 dir_de = sysv_dotdot(old_inode, &dir_page); 227 if (!dir_de) 228 goto out_old; 229 } 230 231 if (new_inode) { 232 struct page * new_page; 233 struct sysv_dir_entry * new_de; 234 235 err = -ENOTEMPTY; 236 if (dir_de && !sysv_empty_dir(new_inode)) 237 goto out_dir; 238 239 err = -ENOENT; 240 new_de = sysv_find_entry(new_dentry, &new_page); 241 if (!new_de) 242 goto out_dir; 243 sysv_set_link(new_de, new_page, old_inode); 244 new_inode->i_ctime = CURRENT_TIME_SEC; 245 if (dir_de) 246 drop_nlink(new_inode); 247 inode_dec_link_count(new_inode); 248 } else { 249 err = sysv_add_link(new_dentry, old_inode); 250 if (err) 251 goto out_dir; 252 if (dir_de) 253 inode_inc_link_count(new_dir); 254 } 255 256 sysv_delete_entry(old_de, old_page); 257 mark_inode_dirty(old_inode); 258 259 if (dir_de) { 260 sysv_set_link(dir_de, dir_page, new_dir); 261 inode_dec_link_count(old_dir); 262 } 263 return 0; 264 265out_dir: 266 if (dir_de) { 267 kunmap(dir_page); 268 page_cache_release(dir_page); 269 } 270out_old: 271 kunmap(old_page); 272 page_cache_release(old_page); 273out: 274 return err; 275} 276 277/* 278 * directories can handle most operations... 279 */ 280const struct inode_operations sysv_dir_inode_operations = { 281 .create = sysv_create, 282 .lookup = sysv_lookup, 283 .link = sysv_link, 284 .unlink = sysv_unlink, 285 .symlink = sysv_symlink, 286 .mkdir = sysv_mkdir, 287 .rmdir = sysv_rmdir, 288 .mknod = sysv_mknod, 289 .rename = sysv_rename, 290 .getattr = sysv_getattr, 291}; 292