1 /* 2 * linux/fs/minix/namei.c 3 * 4 * Copyright (C) 1991, 1992 Linus Torvalds 5 */ 6 7 #include "minix.h" 8 9 static int add_nondir(struct dentry *dentry, struct inode *inode) 10 { 11 int err = minix_add_link(dentry, inode); 12 if (!err) { 13 d_instantiate(dentry, inode); 14 return 0; 15 } 16 inode_dec_link_count(inode); 17 iput(inode); 18 return err; 19 } 20 21 static struct dentry *minix_lookup(struct inode * dir, struct dentry *dentry, struct nameidata *nd) 22 { 23 struct inode * inode = NULL; 24 ino_t ino; 25 26 dentry->d_op = dir->i_sb->s_root->d_op; 27 28 if (dentry->d_name.len > minix_sb(dir->i_sb)->s_namelen) 29 return ERR_PTR(-ENAMETOOLONG); 30 31 ino = minix_inode_by_name(dentry); 32 if (ino) { 33 inode = minix_iget(dir->i_sb, ino); 34 if (IS_ERR(inode)) 35 return ERR_CAST(inode); 36 } 37 d_add(dentry, inode); 38 return NULL; 39 } 40 41 static int minix_mknod(struct inode * dir, struct dentry *dentry, int mode, dev_t rdev) 42 { 43 int error; 44 struct inode *inode; 45 46 if (!old_valid_dev(rdev)) 47 return -EINVAL; 48 49 inode = minix_new_inode(dir, mode, &error); 50 51 if (inode) { 52 minix_set_inode(inode, rdev); 53 mark_inode_dirty(inode); 54 error = add_nondir(dentry, inode); 55 } 56 return error; 57 } 58 59 static int minix_create(struct inode * dir, struct dentry *dentry, int mode, 60 struct nameidata *nd) 61 { 62 return minix_mknod(dir, dentry, mode, 0); 63 } 64 65 static int minix_symlink(struct inode * dir, struct dentry *dentry, 66 const char * symname) 67 { 68 int err = -ENAMETOOLONG; 69 int i = strlen(symname)+1; 70 struct inode * inode; 71 72 if (i > dir->i_sb->s_blocksize) 73 goto out; 74 75 inode = minix_new_inode(dir, S_IFLNK | 0777, &err); 76 if (!inode) 77 goto out; 78 79 minix_set_inode(inode, 0); 80 err = page_symlink(inode, symname, i); 81 if (err) 82 goto out_fail; 83 84 err = add_nondir(dentry, inode); 85 out: 86 return err; 87 88 out_fail: 89 inode_dec_link_count(inode); 90 iput(inode); 91 goto out; 92 } 93 94 static int minix_link(struct dentry * old_dentry, struct inode * dir, 95 struct dentry *dentry) 96 { 97 struct inode *inode = old_dentry->d_inode; 98 99 if (inode->i_nlink >= minix_sb(inode->i_sb)->s_link_max) 100 return -EMLINK; 101 102 inode->i_ctime = CURRENT_TIME_SEC; 103 inode_inc_link_count(inode); 104 atomic_inc(&inode->i_count); 105 return add_nondir(dentry, inode); 106 } 107 108 static int minix_mkdir(struct inode * dir, struct dentry *dentry, int mode) 109 { 110 struct inode * inode; 111 int err = -EMLINK; 112 113 if (dir->i_nlink >= minix_sb(dir->i_sb)->s_link_max) 114 goto out; 115 116 inode_inc_link_count(dir); 117 118 inode = minix_new_inode(dir, mode, &err); 119 if (!inode) 120 goto out_dir; 121 122 minix_set_inode(inode, 0); 123 124 inode_inc_link_count(inode); 125 126 err = minix_make_empty(inode, dir); 127 if (err) 128 goto out_fail; 129 130 err = minix_add_link(dentry, inode); 131 if (err) 132 goto out_fail; 133 134 d_instantiate(dentry, inode); 135 out: 136 return err; 137 138 out_fail: 139 inode_dec_link_count(inode); 140 inode_dec_link_count(inode); 141 iput(inode); 142 out_dir: 143 inode_dec_link_count(dir); 144 goto out; 145 } 146 147 static int minix_unlink(struct inode * dir, struct dentry *dentry) 148 { 149 int err = -ENOENT; 150 struct inode * inode = dentry->d_inode; 151 struct page * page; 152 struct minix_dir_entry * de; 153 154 de = minix_find_entry(dentry, &page); 155 if (!de) 156 goto end_unlink; 157 158 err = minix_delete_entry(de, page); 159 if (err) 160 goto end_unlink; 161 162 inode->i_ctime = dir->i_ctime; 163 inode_dec_link_count(inode); 164 end_unlink: 165 return err; 166 } 167 168 static int minix_rmdir(struct inode * dir, struct dentry *dentry) 169 { 170 struct inode * inode = dentry->d_inode; 171 int err = -ENOTEMPTY; 172 173 if (minix_empty_dir(inode)) { 174 err = minix_unlink(dir, dentry); 175 if (!err) { 176 inode_dec_link_count(dir); 177 inode_dec_link_count(inode); 178 } 179 } 180 return err; 181 } 182 183 static int minix_rename(struct inode * old_dir, struct dentry *old_dentry, 184 struct inode * new_dir, struct dentry *new_dentry) 185 { 186 struct minix_sb_info * info = minix_sb(old_dir->i_sb); 187 struct inode * old_inode = old_dentry->d_inode; 188 struct inode * new_inode = new_dentry->d_inode; 189 struct page * dir_page = NULL; 190 struct minix_dir_entry * dir_de = NULL; 191 struct page * old_page; 192 struct minix_dir_entry * old_de; 193 int err = -ENOENT; 194 195 old_de = minix_find_entry(old_dentry, &old_page); 196 if (!old_de) 197 goto out; 198 199 if (S_ISDIR(old_inode->i_mode)) { 200 err = -EIO; 201 dir_de = minix_dotdot(old_inode, &dir_page); 202 if (!dir_de) 203 goto out_old; 204 } 205 206 if (new_inode) { 207 struct page * new_page; 208 struct minix_dir_entry * new_de; 209 210 err = -ENOTEMPTY; 211 if (dir_de && !minix_empty_dir(new_inode)) 212 goto out_dir; 213 214 err = -ENOENT; 215 new_de = minix_find_entry(new_dentry, &new_page); 216 if (!new_de) 217 goto out_dir; 218 inode_inc_link_count(old_inode); 219 minix_set_link(new_de, new_page, old_inode); 220 new_inode->i_ctime = CURRENT_TIME_SEC; 221 if (dir_de) 222 drop_nlink(new_inode); 223 inode_dec_link_count(new_inode); 224 } else { 225 if (dir_de) { 226 err = -EMLINK; 227 if (new_dir->i_nlink >= info->s_link_max) 228 goto out_dir; 229 } 230 inode_inc_link_count(old_inode); 231 err = minix_add_link(new_dentry, old_inode); 232 if (err) { 233 inode_dec_link_count(old_inode); 234 goto out_dir; 235 } 236 if (dir_de) 237 inode_inc_link_count(new_dir); 238 } 239 240 minix_delete_entry(old_de, old_page); 241 inode_dec_link_count(old_inode); 242 243 if (dir_de) { 244 minix_set_link(dir_de, dir_page, new_dir); 245 inode_dec_link_count(old_dir); 246 } 247 return 0; 248 249 out_dir: 250 if (dir_de) { 251 kunmap(dir_page); 252 page_cache_release(dir_page); 253 } 254 out_old: 255 kunmap(old_page); 256 page_cache_release(old_page); 257 out: 258 return err; 259 } 260 261 /* 262 * directories can handle most operations... 263 */ 264 const struct inode_operations minix_dir_inode_operations = { 265 .create = minix_create, 266 .lookup = minix_lookup, 267 .link = minix_link, 268 .unlink = minix_unlink, 269 .symlink = minix_symlink, 270 .mkdir = minix_mkdir, 271 .rmdir = minix_rmdir, 272 .mknod = minix_mknod, 273 .rename = minix_rename, 274 .getattr = minix_getattr, 275 }; 276