namei.c revision 9a53c3a783c2fa9b969628e65695c11c3e51e673
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 <linux/smp_lock.h> 17#include "sysv.h" 18 19static int add_nondir(struct dentry *dentry, struct inode *inode) 20{ 21 int err = sysv_add_link(dentry, inode); 22 if (!err) { 23 d_instantiate(dentry, inode); 24 return 0; 25 } 26 inode_dec_link_count(inode); 27 iput(inode); 28 return err; 29} 30 31static int sysv_hash(struct dentry *dentry, 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 42struct 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 dentry->d_op = dir->i_sb->s_root->d_op; 52 if (dentry->d_name.len > SYSV_NAMELEN) 53 return ERR_PTR(-ENAMETOOLONG); 54 ino = sysv_inode_by_name(dentry); 55 56 if (ino) { 57 inode = iget(dir->i_sb, ino); 58 if (!inode) 59 return ERR_PTR(-EACCES); 60 } 61 d_add(dentry, inode); 62 return NULL; 63} 64 65static int sysv_mknod(struct inode * dir, struct dentry * dentry, int mode, dev_t rdev) 66{ 67 struct inode * inode; 68 int err; 69 70 if (!old_valid_dev(rdev)) 71 return -EINVAL; 72 73 inode = sysv_new_inode(dir, mode); 74 err = PTR_ERR(inode); 75 76 if (!IS_ERR(inode)) { 77 sysv_set_inode(inode, rdev); 78 mark_inode_dirty(inode); 79 err = add_nondir(dentry, inode); 80 } 81 return err; 82} 83 84static int sysv_create(struct inode * dir, struct dentry * dentry, int mode, struct nameidata *nd) 85{ 86 return sysv_mknod(dir, dentry, mode, 0); 87} 88 89static int sysv_symlink(struct inode * dir, struct dentry * dentry, 90 const char * symname) 91{ 92 int err = -ENAMETOOLONG; 93 int l = strlen(symname)+1; 94 struct inode * inode; 95 96 if (l > dir->i_sb->s_blocksize) 97 goto out; 98 99 inode = sysv_new_inode(dir, S_IFLNK|0777); 100 err = PTR_ERR(inode); 101 if (IS_ERR(inode)) 102 goto out; 103 104 sysv_set_inode(inode, 0); 105 err = page_symlink(inode, symname, l); 106 if (err) 107 goto out_fail; 108 109 mark_inode_dirty(inode); 110 err = add_nondir(dentry, inode); 111out: 112 return err; 113 114out_fail: 115 inode_dec_link_count(inode); 116 iput(inode); 117 goto out; 118} 119 120static int sysv_link(struct dentry * old_dentry, struct inode * dir, 121 struct dentry * dentry) 122{ 123 struct inode *inode = old_dentry->d_inode; 124 125 if (inode->i_nlink >= SYSV_SB(inode->i_sb)->s_link_max) 126 return -EMLINK; 127 128 inode->i_ctime = CURRENT_TIME_SEC; 129 inode_inc_link_count(inode); 130 atomic_inc(&inode->i_count); 131 132 return add_nondir(dentry, inode); 133} 134 135static int sysv_mkdir(struct inode * dir, struct dentry *dentry, int mode) 136{ 137 struct inode * inode; 138 int err = -EMLINK; 139 140 if (dir->i_nlink >= SYSV_SB(dir->i_sb)->s_link_max) 141 goto out; 142 inode_inc_link_count(dir); 143 144 inode = sysv_new_inode(dir, S_IFDIR|mode); 145 err = PTR_ERR(inode); 146 if (IS_ERR(inode)) 147 goto out_dir; 148 149 sysv_set_inode(inode, 0); 150 151 inode_inc_link_count(inode); 152 153 err = sysv_make_empty(inode, dir); 154 if (err) 155 goto out_fail; 156 157 err = sysv_add_link(dentry, inode); 158 if (err) 159 goto out_fail; 160 161 d_instantiate(dentry, inode); 162out: 163 return err; 164 165out_fail: 166 inode_dec_link_count(inode); 167 inode_dec_link_count(inode); 168 iput(inode); 169out_dir: 170 inode_dec_link_count(dir); 171 goto out; 172} 173 174static int sysv_unlink(struct inode * dir, struct dentry * dentry) 175{ 176 struct inode * inode = dentry->d_inode; 177 struct page * page; 178 struct sysv_dir_entry * de; 179 int err = -ENOENT; 180 181 de = sysv_find_entry(dentry, &page); 182 if (!de) 183 goto out; 184 185 err = sysv_delete_entry (de, page); 186 if (err) 187 goto out; 188 189 inode->i_ctime = dir->i_ctime; 190 inode_dec_link_count(inode); 191out: 192 return err; 193} 194 195static int sysv_rmdir(struct inode * dir, struct dentry * dentry) 196{ 197 struct inode *inode = dentry->d_inode; 198 int err = -ENOTEMPTY; 199 200 if (sysv_empty_dir(inode)) { 201 err = sysv_unlink(dir, dentry); 202 if (!err) { 203 inode->i_size = 0; 204 inode_dec_link_count(inode); 205 inode_dec_link_count(dir); 206 } 207 } 208 return err; 209} 210 211/* 212 * Anybody can rename anything with this: the permission checks are left to the 213 * higher-level routines. 214 */ 215static int sysv_rename(struct inode * old_dir, struct dentry * old_dentry, 216 struct inode * new_dir, struct dentry * new_dentry) 217{ 218 struct inode * old_inode = old_dentry->d_inode; 219 struct inode * new_inode = new_dentry->d_inode; 220 struct page * dir_page = NULL; 221 struct sysv_dir_entry * dir_de = NULL; 222 struct page * old_page; 223 struct sysv_dir_entry * old_de; 224 int err = -ENOENT; 225 226 old_de = sysv_find_entry(old_dentry, &old_page); 227 if (!old_de) 228 goto out; 229 230 if (S_ISDIR(old_inode->i_mode)) { 231 err = -EIO; 232 dir_de = sysv_dotdot(old_inode, &dir_page); 233 if (!dir_de) 234 goto out_old; 235 } 236 237 if (new_inode) { 238 struct page * new_page; 239 struct sysv_dir_entry * new_de; 240 241 err = -ENOTEMPTY; 242 if (dir_de && !sysv_empty_dir(new_inode)) 243 goto out_dir; 244 245 err = -ENOENT; 246 new_de = sysv_find_entry(new_dentry, &new_page); 247 if (!new_de) 248 goto out_dir; 249 inode_inc_link_count(old_inode); 250 sysv_set_link(new_de, new_page, old_inode); 251 new_inode->i_ctime = CURRENT_TIME_SEC; 252 if (dir_de) 253 drop_nlink(new_inode); 254 inode_dec_link_count(new_inode); 255 } else { 256 if (dir_de) { 257 err = -EMLINK; 258 if (new_dir->i_nlink >= SYSV_SB(new_dir->i_sb)->s_link_max) 259 goto out_dir; 260 } 261 inode_inc_link_count(old_inode); 262 err = sysv_add_link(new_dentry, old_inode); 263 if (err) { 264 inode_dec_link_count(old_inode); 265 goto out_dir; 266 } 267 if (dir_de) 268 inode_inc_link_count(new_dir); 269 } 270 271 sysv_delete_entry(old_de, old_page); 272 inode_dec_link_count(old_inode); 273 274 if (dir_de) { 275 sysv_set_link(dir_de, dir_page, new_dir); 276 inode_dec_link_count(old_dir); 277 } 278 return 0; 279 280out_dir: 281 if (dir_de) { 282 kunmap(dir_page); 283 page_cache_release(dir_page); 284 } 285out_old: 286 kunmap(old_page); 287 page_cache_release(old_page); 288out: 289 return err; 290} 291 292/* 293 * directories can handle most operations... 294 */ 295struct inode_operations sysv_dir_inode_operations = { 296 .create = sysv_create, 297 .lookup = sysv_lookup, 298 .link = sysv_link, 299 .unlink = sysv_unlink, 300 .symlink = sysv_symlink, 301 .mkdir = sysv_mkdir, 302 .rmdir = sysv_rmdir, 303 .mknod = sysv_mknod, 304 .rename = sysv_rename, 305 .getattr = sysv_getattr, 306}; 307