fs/ext2/namei.c

   1 /*
   2  * linux/fs/ext2/namei.c
   3  *
   4  * Rewrite to pagecache. Almost all code had been changed, so blame me
   5  * if the things go wrong. Please, send bug reports to
   6  * viro@parcelfarce.linux.theplanet.co.uk
   7  *
   8  * Stuff here is basically a glue between the VFS and generic UNIXish
   9  * filesystem that keeps everything in pagecache. All knowledge of the
  10  * directory layout is in fs/ext2/dir.c - it turned out to be easily separatable
  11  * and it's easier to debug that way. In principle we might want to
  12  * generalize that a bit and turn it into a library. Or not.
  13  *
  14  * The only non-static object here is ext2_dir_inode_operations.
  15  *
  16  * TODO: get rid of kmap() use, add readahead.
  17  *
  18  * Copyright (C) 1992, 1993, 1994, 1995
  19  * Remy Card (card@masi.ibp.fr)
  20  * Laboratoire MASI - Institut Blaise Pascal
  21  * Universite Pierre et Marie Curie (Paris VI)
  22  *
  23  *  from
  24  *
  25  *  linux/fs/minix/namei.c
  26  *
  27  *  Copyright (C) 1991, 1992  Linus Torvalds
  28  *
  29  *  Big-endian to little-endian byte-swapping/bitmaps by
  30  *        David S. Miller (davem@caip.rutgers.edu), 1995
  31  */
  32
  33 #include <linux/pagemap.h>
  34 #include <linux/quotaops.h>
  35 #include "ext2.h"
  36 #include "xattr.h"
  37 #include "acl.h"
  38
  39 static inline int ext2_add_nondir(struct dentry *dentry, struct inode *inode)
  40 {
  41         int err = ext2_add_link(dentry, inode);
  42         if (!err) {
  43                 unlock_new_inode(inode);
  44                 d_instantiate(dentry, inode);
  45                 return 0;
  46         }
  47         inode_dec_link_count(inode);
  48         unlock_new_inode(inode);
  49         iput(inode);
  50         return err;
  51 }
  52
  53 /*
  54  * Methods themselves.
  55  */
  56
  57 static struct dentry *ext2_lookup(struct inode * dir, struct dentry *dentry, unsigned int flags)
  58 {
  59         struct inode * inode;
  60         ino_t ino;
  61
  62         if (dentry->d_name.len > EXT2_NAME_LEN)
  63                 return ERR_PTR(-ENAMETOOLONG);
  64
  65         ino = ext2_inode_by_name(dir, &dentry->d_name);
  66         inode = NULL;
  67         if (ino) {
  68                 inode = ext2_iget(dir->i_sb, ino);
  69                 if (inode == ERR_PTR(-ESTALE)) {
  70                         ext2_error(dir->i_sb, __func__,
  71                                         "deleted inode referenced: %lu",
  72                                         (unsigned long) ino);
  73                         return ERR_PTR(-EIO);
  74                 }
  75         }
  76         return d_splice_alias(inode, dentry);
  77 }
  78
  79 struct dentry *ext2_get_parent(struct dentry *child)
  80 {
  81         struct qstr dotdot = QSTR_INIT("..", 2);
  82         unsigned long ino = ext2_inode_by_name(child->d_inode, &dotdot);
  83         if (!ino)
  84                 return ERR_PTR(-ENOENT);
  85         return d_obtain_alias(ext2_iget(child->d_inode->i_sb, ino));
  86 }
  87
  88 /*
  89  * By the time this is called, we already have created
  90  * the directory cache entry for the new file, but it
  91  * is so far negative - it has no inode.
  92  *
  93  * If the create succeeds, we fill in the inode information
  94  * with d_instantiate().
  95  */
  96 static int ext2_create (struct inode * dir, struct dentry * dentry, umode_t mode, bool excl)
  97 {
  98         struct inode *inode;
  99
 100         dquot_initialize(dir);
 101
 102         inode = ext2_new_inode(dir, mode, &dentry->d_name);
 103         if (IS_ERR(inode))
 104                 return PTR_ERR(inode);
 105
 106         inode->i_op = &ext2_file_inode_operations;
 107         if (test_opt(inode->i_sb, DAX)) {
 108                 inode->i_mapping->a_ops = &ext2_aops;
 109                 inode->i_fop = &ext2_dax_file_operations;
 110         } else if (test_opt(inode->i_sb, NOBH)) {
 111                 inode->i_mapping->a_ops = &ext2_nobh_aops;
 112                 inode->i_fop = &ext2_file_operations;
 113         } else {
 114                 inode->i_mapping->a_ops = &ext2_aops;
 115                 inode->i_fop = &ext2_file_operations;
 116         }
 117         mark_inode_dirty(inode);
 118         return ext2_add_nondir(dentry, inode);
 119 }
 120
 121 static int ext2_tmpfile(struct inode *dir, struct dentry *dentry, umode_t mode)
 122 {
 123         struct inode *inode = ext2_new_inode(dir, mode, NULL);
 124         if (IS_ERR(inode))
 125                 return PTR_ERR(inode);
 126
 127         inode->i_op = &ext2_file_inode_operations;
 128         if (test_opt(inode->i_sb, DAX)) {
 129                 inode->i_mapping->a_ops = &ext2_aops;
 130                 inode->i_fop = &ext2_dax_file_operations;
 131         } else if (test_opt(inode->i_sb, NOBH)) {
 132                 inode->i_mapping->a_ops = &ext2_nobh_aops;
 133                 inode->i_fop = &ext2_file_operations;
 134         } else {
 135                 inode->i_mapping->a_ops = &ext2_aops;
 136                 inode->i_fop = &ext2_file_operations;
 137         }
 138         mark_inode_dirty(inode);
 139         d_tmpfile(dentry, inode);
 140         unlock_new_inode(inode);
 141         return 0;
 142 }
 143
 144 static int ext2_mknod (struct inode * dir, struct dentry *dentry, umode_t mode, dev_t rdev)
 145 {
 146         struct inode * inode;
 147         int err;
 148
 149         if (!new_valid_dev(rdev))
 150                 return -EINVAL;
 151
 152         dquot_initialize(dir);
 153
 154         inode = ext2_new_inode (dir, mode, &dentry->d_name);
 155         err = PTR_ERR(inode);
 156         if (!IS_ERR(inode)) {
 157                 init_special_inode(inode, inode->i_mode, rdev);
 158 #ifdef CONFIG_EXT2_FS_XATTR
 159                 inode->i_op = &ext2_special_inode_operations;
 160 #endif
 161                 mark_inode_dirty(inode);
 162                 err = ext2_add_nondir(dentry, inode);
 163         }
 164         return err;
 165 }
 166
 167 static int ext2_symlink (struct inode * dir, struct dentry * dentry,
 168         const char * symname)
 169 {
 170         struct super_block * sb = dir->i_sb;
 171         int err = -ENAMETOOLONG;
 172         unsigned l = strlen(symname)+1;
 173         struct inode * inode;
 174
 175         if (l > sb->s_blocksize)
 176                 goto out;
 177
 178         dquot_initialize(dir);
 179
 180         inode = ext2_new_inode (dir, S_IFLNK | S_IRWXUGO, &dentry->d_name);
 181         err = PTR_ERR(inode);
 182         if (IS_ERR(inode))
 183                 goto out;
 184
 185         if (l > sizeof (EXT2_I(inode)->i_data)) {
 186                 /* slow symlink */
 187                 inode->i_op = &ext2_symlink_inode_operations;
 188                 if (test_opt(inode->i_sb, NOBH))
 189                         inode->i_mapping->a_ops = &ext2_nobh_aops;
 190                 else
 191                         inode->i_mapping->a_ops = &ext2_aops;
 192                 err = page_symlink(inode, symname, l);
 193                 if (err)
 194                         goto out_fail;
 195         } else {
 196                 /* fast symlink */
 197                 inode->i_op = &ext2_fast_symlink_inode_operations;
 198                 memcpy((char*)(EXT2_I(inode)->i_data),symname,l);
 199                 inode->i_size = l-1;
 200         }
 201         mark_inode_dirty(inode);
 202
 203         err = ext2_add_nondir(dentry, inode);
 204 out:
 205         return err;
 206
 207 out_fail:
 208         inode_dec_link_count(inode);
 209         unlock_new_inode(inode);
 210         iput (inode);
 211         goto out;
 212 }
 213
 214 static int ext2_link (struct dentry * old_dentry, struct inode * dir,
 215         struct dentry *dentry)
 216 {
 217         struct inode *inode = old_dentry->d_inode;
 218         int err;
 219
 220         dquot_initialize(dir);
 221
 222         inode->i_ctime = CURRENT_TIME_SEC;
 223         inode_inc_link_count(inode);
 224         ihold(inode);
 225
 226         err = ext2_add_link(dentry, inode);
 227         if (!err) {
 228                 d_instantiate(dentry, inode);
 229                 return 0;
 230         }
 231         inode_dec_link_count(inode);
 232         iput(inode);
 233         return err;
 234 }
 235
 236 static int ext2_mkdir(struct inode * dir, struct dentry * dentry, umode_t mode)
 237 {
 238         struct inode * inode;
 239         int err;
 240
 241         dquot_initialize(dir);
 242
 243         inode_inc_link_count(dir);
 244
 245         inode = ext2_new_inode(dir, S_IFDIR | mode, &dentry->d_name);
 246         err = PTR_ERR(inode);
 247         if (IS_ERR(inode))
 248                 goto out_dir;
 249
 250         inode->i_op = &ext2_dir_inode_operations;
 251         inode->i_fop = &ext2_dir_operations;
 252         if (test_opt(inode->i_sb, NOBH))
 253                 inode->i_mapping->a_ops = &ext2_nobh_aops;
 254         else
 255                 inode->i_mapping->a_ops = &ext2_aops;
 256
 257         inode_inc_link_count(inode);
 258
 259         err = ext2_make_empty(inode, dir);
 260         if (err)
 261                 goto out_fail;
 262
 263         err = ext2_add_link(dentry, inode);
 264         if (err)
 265                 goto out_fail;
 266
 267         unlock_new_inode(inode);
 268         d_instantiate(dentry, inode);
 269 out:
 270         return err;
 271
 272 out_fail:
 273         inode_dec_link_count(inode);
 274         inode_dec_link_count(inode);
 275         unlock_new_inode(inode);
 276         iput(inode);
 277 out_dir:
 278         inode_dec_link_count(dir);
 279         goto out;
 280 }
 281
 282 static int ext2_unlink(struct inode * dir, struct dentry *dentry)
 283 {
 284         struct inode * inode = dentry->d_inode;
 285         struct ext2_dir_entry_2 * de;
 286         struct page * page;
 287         int err = -ENOENT;
 288
 289         dquot_initialize(dir);
 290
 291         de = ext2_find_entry (dir, &dentry->d_name, &page);
 292         if (!de)
 293                 goto out;
 294
 295         err = ext2_delete_entry (de, page);
 296         if (err)
 297                 goto out;
 298
 299         inode->i_ctime = dir->i_ctime;
 300         inode_dec_link_count(inode);
 301         err = 0;
 302 out:
 303         return err;
 304 }
 305
 306 static int ext2_rmdir (struct inode * dir, struct dentry *dentry)
 307 {
 308         struct inode * inode = dentry->d_inode;
 309         int err = -ENOTEMPTY;
 310
 311         if (ext2_empty_dir(inode)) {
 312                 err = ext2_unlink(dir, dentry);
 313                 if (!err) {
 314                         inode->i_size = 0;
 315                         inode_dec_link_count(inode);
 316                         inode_dec_link_count(dir);
 317                 }
 318         }
 319         return err;
 320 }
 321
 322 static int ext2_rename (struct inode * old_dir, struct dentry * old_dentry,
 323         struct inode * new_dir, struct dentry * new_dentry )
 324 {
 325         struct inode * old_inode = old_dentry->d_inode;
 326         struct inode * new_inode = new_dentry->d_inode;
 327         struct page * dir_page = NULL;
 328         struct ext2_dir_entry_2 * dir_de = NULL;
 329         struct page * old_page;
 330         struct ext2_dir_entry_2 * old_de;
 331         int err = -ENOENT;
 332
 333         dquot_initialize(old_dir);
 334         dquot_initialize(new_dir);
 335
 336         old_de = ext2_find_entry (old_dir, &old_dentry->d_name, &old_page);
 337         if (!old_de)
 338                 goto out;
 339
 340         if (S_ISDIR(old_inode->i_mode)) {
 341                 err = -EIO;
 342                 dir_de = ext2_dotdot(old_inode, &dir_page);
 343                 if (!dir_de)
 344                         goto out_old;
 345         }
 346
 347         if (new_inode) {
 348                 struct page *new_page;
 349                 struct ext2_dir_entry_2 *new_de;
 350
 351                 err = -ENOTEMPTY;
 352                 if (dir_de && !ext2_empty_dir (new_inode))
 353                         goto out_dir;
 354
 355                 err = -ENOENT;
 356                 new_de = ext2_find_entry (new_dir, &new_dentry->d_name, &new_page);
 357                 if (!new_de)
 358                         goto out_dir;
 359                 ext2_set_link(new_dir, new_de, new_page, old_inode, 1);
 360                 new_inode->i_ctime = CURRENT_TIME_SEC;
 361                 if (dir_de)
 362                         drop_nlink(new_inode);
 363                 inode_dec_link_count(new_inode);
 364         } else {
 365                 err = ext2_add_link(new_dentry, old_inode);
 366                 if (err)
 367                         goto out_dir;
 368                 if (dir_de)
 369                         inode_inc_link_count(new_dir);
 370         }
 371
 372         /*
 373          * Like most other Unix systems, set the ctime for inodes on a
 374          * rename.
 375          */
 376         old_inode->i_ctime = CURRENT_TIME_SEC;
 377         mark_inode_dirty(old_inode);
 378
 379         ext2_delete_entry (old_de, old_page);
 380
 381         if (dir_de) {
 382                 if (old_dir != new_dir)
 383                         ext2_set_link(old_inode, dir_de, dir_page, new_dir, 0);
 384                 else {
 385                         kunmap(dir_page);
 386                         page_cache_release(dir_page);
 387                 }
 388                 inode_dec_link_count(old_dir);
 389         }
 390         return 0;
 391
 392
 393 out_dir:
 394         if (dir_de) {
 395                 kunmap(dir_page);
 396                 page_cache_release(dir_page);
 397         }
 398 out_old:
 399         kunmap(old_page);
 400         page_cache_release(old_page);
 401 out:
 402         return err;
 403 }
 404
 405 const struct inode_operations ext2_dir_inode_operations = {
 406         .create         = ext2_create,
 407         .lookup         = ext2_lookup,
 408         .link           = ext2_link,
 409         .unlink         = ext2_unlink,
 410         .symlink        = ext2_symlink,
 411         .mkdir          = ext2_mkdir,
 412         .rmdir          = ext2_rmdir,
 413         .mknod          = ext2_mknod,
 414         .rename         = ext2_rename,
 415 #ifdef CONFIG_EXT2_FS_XATTR
 416         .setxattr       = generic_setxattr,
 417         .getxattr       = generic_getxattr,
 418         .listxattr      = ext2_listxattr,
 419         .removexattr    = generic_removexattr,
 420 #endif
 421         .setattr        = ext2_setattr,
 422         .get_acl        = ext2_get_acl,
 423         .set_acl        = ext2_set_acl,
 424         .tmpfile        = ext2_tmpfile,
 425 };
 426
 427 const struct inode_operations ext2_special_inode_operations = {
 428 #ifdef CONFIG_EXT2_FS_XATTR
 429         .setxattr       = generic_setxattr,
 430         .getxattr       = generic_getxattr,
 431         .listxattr      = ext2_listxattr,
 432         .removexattr    = generic_removexattr,
 433 #endif
 434         .setattr        = ext2_setattr,
 435         .get_acl        = ext2_get_acl,
 436         .set_acl        = ext2_set_acl,
 437 };