1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * linux/fs/minix/namei.c 4 * 5 * Copyright (C) 1991, 1992 Linus Torvalds 6 */ 7 8 #include "minix.h" 9 10 static int add_nondir(struct dentry *dentry, struct inode *inode) 11 { 12 int err = minix_add_link(dentry, inode); 13 if (!err) { 14 d_instantiate(dentry, inode); 15 return 0; 16 } 17 inode_dec_link_count(inode); 18 iput(inode); 19 return err; 20 } 21 22 static struct dentry *minix_lookup(struct inode * dir, struct dentry *dentry, unsigned int flags) 23 { 24 struct inode * inode = NULL; 25 ino_t ino; 26 27 if (dentry->d_name.len > minix_sb(dir->i_sb)->s_namelen) 28 return ERR_PTR(-ENAMETOOLONG); 29 30 ino = minix_inode_by_name(dentry); 31 if (ino) 32 inode = minix_iget(dir->i_sb, ino); 33 return d_splice_alias(inode, dentry); 34 } 35 36 static int minix_mknod(struct user_namespace *mnt_userns, struct inode *dir, 37 struct dentry *dentry, umode_t mode, dev_t rdev) 38 { 39 int error; 40 struct inode *inode; 41 42 if (!old_valid_dev(rdev)) 43 return -EINVAL; 44 45 inode = minix_new_inode(dir, mode, &error); 46 47 if (inode) { 48 minix_set_inode(inode, rdev); 49 mark_inode_dirty(inode); 50 error = add_nondir(dentry, inode); 51 } 52 return error; 53 } 54 55 static int minix_tmpfile(struct user_namespace *mnt_userns, struct inode *dir, 56 struct file *file, umode_t mode) 57 { 58 int error; 59 struct inode *inode = minix_new_inode(dir, mode, &error); 60 if (inode) { 61 minix_set_inode(inode, 0); 62 mark_inode_dirty(inode); 63 d_tmpfile(file, inode); 64 } 65 return finish_open_simple(file, error); 66 } 67 68 static int minix_create(struct user_namespace *mnt_userns, struct inode *dir, 69 struct dentry *dentry, umode_t mode, bool excl) 70 { 71 return minix_mknod(mnt_userns, dir, dentry, mode, 0); 72 } 73 74 static int minix_symlink(struct user_namespace *mnt_userns, struct inode *dir, 75 struct dentry *dentry, const char *symname) 76 { 77 int err = -ENAMETOOLONG; 78 int i = strlen(symname)+1; 79 struct inode * inode; 80 81 if (i > dir->i_sb->s_blocksize) 82 goto out; 83 84 inode = minix_new_inode(dir, S_IFLNK | 0777, &err); 85 if (!inode) 86 goto out; 87 88 minix_set_inode(inode, 0); 89 err = page_symlink(inode, symname, i); 90 if (err) 91 goto out_fail; 92 93 err = add_nondir(dentry, inode); 94 out: 95 return err; 96 97 out_fail: 98 inode_dec_link_count(inode); 99 iput(inode); 100 goto out; 101 } 102 103 static int minix_link(struct dentry * old_dentry, struct inode * dir, 104 struct dentry *dentry) 105 { 106 struct inode *inode = d_inode(old_dentry); 107 108 inode->i_ctime = current_time(inode); 109 inode_inc_link_count(inode); 110 ihold(inode); 111 return add_nondir(dentry, inode); 112 } 113 114 static int minix_mkdir(struct user_namespace *mnt_userns, struct inode *dir, 115 struct dentry *dentry, umode_t mode) 116 { 117 struct inode * inode; 118 int err; 119 120 inode_inc_link_count(dir); 121 122 inode = minix_new_inode(dir, S_IFDIR | mode, &err); 123 if (!inode) 124 goto out_dir; 125 126 minix_set_inode(inode, 0); 127 128 inode_inc_link_count(inode); 129 130 err = minix_make_empty(inode, dir); 131 if (err) 132 goto out_fail; 133 134 err = minix_add_link(dentry, inode); 135 if (err) 136 goto out_fail; 137 138 d_instantiate(dentry, inode); 139 out: 140 return err; 141 142 out_fail: 143 inode_dec_link_count(inode); 144 inode_dec_link_count(inode); 145 iput(inode); 146 out_dir: 147 inode_dec_link_count(dir); 148 goto out; 149 } 150 151 static int minix_unlink(struct inode * dir, struct dentry *dentry) 152 { 153 int err = -ENOENT; 154 struct inode * inode = d_inode(dentry); 155 struct page * page; 156 struct minix_dir_entry * de; 157 158 de = minix_find_entry(dentry, &page); 159 if (!de) 160 goto end_unlink; 161 162 err = minix_delete_entry(de, page); 163 if (err) 164 goto end_unlink; 165 166 inode->i_ctime = dir->i_ctime; 167 inode_dec_link_count(inode); 168 end_unlink: 169 return err; 170 } 171 172 static int minix_rmdir(struct inode * dir, struct dentry *dentry) 173 { 174 struct inode * inode = d_inode(dentry); 175 int err = -ENOTEMPTY; 176 177 if (minix_empty_dir(inode)) { 178 err = minix_unlink(dir, dentry); 179 if (!err) { 180 inode_dec_link_count(dir); 181 inode_dec_link_count(inode); 182 } 183 } 184 return err; 185 } 186 187 static int minix_rename(struct user_namespace *mnt_userns, 188 struct inode *old_dir, struct dentry *old_dentry, 189 struct inode *new_dir, struct dentry *new_dentry, 190 unsigned int flags) 191 { 192 struct inode * old_inode = d_inode(old_dentry); 193 struct inode * new_inode = d_inode(new_dentry); 194 struct page * dir_page = NULL; 195 struct minix_dir_entry * dir_de = NULL; 196 struct page * old_page; 197 struct minix_dir_entry * old_de; 198 int err = -ENOENT; 199 200 if (flags & ~RENAME_NOREPLACE) 201 return -EINVAL; 202 203 old_de = minix_find_entry(old_dentry, &old_page); 204 if (!old_de) 205 goto out; 206 207 if (S_ISDIR(old_inode->i_mode)) { 208 err = -EIO; 209 dir_de = minix_dotdot(old_inode, &dir_page); 210 if (!dir_de) 211 goto out_old; 212 } 213 214 if (new_inode) { 215 struct page * new_page; 216 struct minix_dir_entry * new_de; 217 218 err = -ENOTEMPTY; 219 if (dir_de && !minix_empty_dir(new_inode)) 220 goto out_dir; 221 222 err = -ENOENT; 223 new_de = minix_find_entry(new_dentry, &new_page); 224 if (!new_de) 225 goto out_dir; 226 minix_set_link(new_de, new_page, old_inode); 227 new_inode->i_ctime = current_time(new_inode); 228 if (dir_de) 229 drop_nlink(new_inode); 230 inode_dec_link_count(new_inode); 231 } else { 232 err = minix_add_link(new_dentry, old_inode); 233 if (err) 234 goto out_dir; 235 if (dir_de) 236 inode_inc_link_count(new_dir); 237 } 238 239 minix_delete_entry(old_de, old_page); 240 mark_inode_dirty(old_inode); 241 242 if (dir_de) { 243 minix_set_link(dir_de, dir_page, new_dir); 244 inode_dec_link_count(old_dir); 245 } 246 return 0; 247 248 out_dir: 249 if (dir_de) { 250 kunmap(dir_page); 251 put_page(dir_page); 252 } 253 out_old: 254 kunmap(old_page); 255 put_page(old_page); 256 out: 257 return err; 258 } 259 260 /* 261 * directories can handle most operations... 262 */ 263 const struct inode_operations minix_dir_inode_operations = { 264 .create = minix_create, 265 .lookup = minix_lookup, 266 .link = minix_link, 267 .unlink = minix_unlink, 268 .symlink = minix_symlink, 269 .mkdir = minix_mkdir, 270 .rmdir = minix_rmdir, 271 .mknod = minix_mknod, 272 .rename = minix_rename, 273 .getattr = minix_getattr, 274 .tmpfile = minix_tmpfile, 275 }; 276