fs/ufs/namei.c

   1 /*
   2  * linux/fs/ufs/namei.c
   3  *
   4  * Migration to usage of "page cache" on May 2006 by
   5  * Evgeniy Dushistov <dushistov@mail.ru> based on ext2 code base.
   6  *
   7  * Copyright (C) 1998
   8  * Daniel Pirkl <daniel.pirkl@email.cz>
   9  * Charles University, Faculty of Mathematics and Physics
  10  *
  11  *  from
  12  *
  13  *  linux/fs/ext2/namei.c
  14  *
  15  * Copyright (C) 1992, 1993, 1994, 1995
  16  * Remy Card (card@masi.ibp.fr)
  17  * Laboratoire MASI - Institut Blaise Pascal
  18  * Universite Pierre et Marie Curie (Paris VI)
  19  *
  20  *  from
  21  *
  22  *  linux/fs/minix/namei.c
  23  *
  24  *  Copyright (C) 1991, 1992  Linus Torvalds
  25  *
  26  *  Big-endian to little-endian byte-swapping/bitmaps by
  27  *        David S. Miller (davem@caip.rutgers.edu), 1995
  28  */
  29
  30 #include <linux/time.h>
  31 #include <linux/fs.h>
  32
  33 #include "ufs_fs.h"
  34 #include "ufs.h"
  35 #include "util.h"
  36
  37 static inline int ufs_add_nondir(struct dentry *dentry, struct inode *inode)
  38 {
  39         int err = ufs_add_link(dentry, inode);
  40         if (!err) {
  41                 d_instantiate(dentry, inode);
  42                 return 0;
  43         }
  44         inode_dec_link_count(inode);
  45         iput(inode);
  46         return err;
  47 }
  48
  49 static struct dentry *ufs_lookup(struct inode * dir, struct dentry *dentry, struct nameidata *nd)
  50 {
  51         struct inode * inode = NULL;
  52         ino_t ino;
  53
  54         if (dentry->d_name.len > UFS_MAXNAMLEN)
  55                 return ERR_PTR(-ENAMETOOLONG);
  56
  57         lock_ufs(dir->i_sb);
  58         ino = ufs_inode_by_name(dir, &dentry->d_name);
  59         if (ino) {
  60                 inode = ufs_iget(dir->i_sb, ino);
  61                 if (IS_ERR(inode)) {
  62                         unlock_ufs(dir->i_sb);
  63                         return ERR_CAST(inode);
  64                 }
  65         }
  66         unlock_ufs(dir->i_sb);
  67         d_add(dentry, inode);
  68         return NULL;
  69 }
  70
  71 /*
  72  * By the time this is called, we already have created
  73  * the directory cache entry for the new file, but it
  74  * is so far negative - it has no inode.
  75  *
  76  * If the create succeeds, we fill in the inode information
  77  * with d_instantiate().
  78  */
  79 static int ufs_create (struct inode * dir, struct dentry * dentry, int mode,
  80                 struct nameidata *nd)
  81 {
  82         struct inode *inode;
  83         int err;
  84
  85         UFSD("BEGIN\n");
  86
  87         inode = ufs_new_inode(dir, mode);
  88         err = PTR_ERR(inode);
  89
  90         if (!IS_ERR(inode)) {
  91                 inode->i_op = &ufs_file_inode_operations;
  92                 inode->i_fop = &ufs_file_operations;
  93                 inode->i_mapping->a_ops = &ufs_aops;
  94                 mark_inode_dirty(inode);
  95                 lock_ufs(dir->i_sb);
  96                 err = ufs_add_nondir(dentry, inode);
  97                 unlock_ufs(dir->i_sb);
  98         }
  99         UFSD("END: err=%d\n", err);
 100         return err;
 101 }
 102
 103 static int ufs_mknod (struct inode * dir, struct dentry *dentry, int mode, dev_t rdev)
 104 {
 105         struct inode *inode;
 106         int err;
 107
 108         if (!old_valid_dev(rdev))
 109                 return -EINVAL;
 110
 111         inode = ufs_new_inode(dir, mode);
 112         err = PTR_ERR(inode);
 113         if (!IS_ERR(inode)) {
 114                 init_special_inode(inode, mode, rdev);
 115                 ufs_set_inode_dev(inode->i_sb, UFS_I(inode), rdev);
 116                 mark_inode_dirty(inode);
 117                 lock_ufs(dir->i_sb);
 118                 err = ufs_add_nondir(dentry, inode);
 119                 unlock_ufs(dir->i_sb);
 120         }
 121         return err;
 122 }
 123
 124 static int ufs_symlink (struct inode * dir, struct dentry * dentry,
 125         const char * symname)
 126 {
 127         struct super_block * sb = dir->i_sb;
 128         int err = -ENAMETOOLONG;
 129         unsigned l = strlen(symname)+1;
 130         struct inode * inode;
 131
 132         if (l > sb->s_blocksize)
 133                 goto out_notlocked;
 134
 135         lock_ufs(dir->i_sb);
 136         inode = ufs_new_inode(dir, S_IFLNK | S_IRWXUGO);
 137         err = PTR_ERR(inode);
 138         if (IS_ERR(inode))
 139                 goto out;
 140
 141         if (l > UFS_SB(sb)->s_uspi->s_maxsymlinklen) {
 142                 /* slow symlink */
 143                 inode->i_op = &ufs_symlink_inode_operations;
 144                 inode->i_mapping->a_ops = &ufs_aops;
 145                 err = page_symlink(inode, symname, l);
 146                 if (err)
 147                         goto out_fail;
 148         } else {
 149                 /* fast symlink */
 150                 inode->i_op = &ufs_fast_symlink_inode_operations;
 151                 memcpy(UFS_I(inode)->i_u1.i_symlink, symname, l);
 152                 inode->i_size = l-1;
 153         }
 154         mark_inode_dirty(inode);
 155
 156         err = ufs_add_nondir(dentry, inode);
 157 out:
 158         unlock_ufs(dir->i_sb);
 159 out_notlocked:
 160         return err;
 161
 162 out_fail:
 163         inode_dec_link_count(inode);
 164         iput(inode);
 165         goto out;
 166 }
 167
 168 static int ufs_link (struct dentry * old_dentry, struct inode * dir,
 169         struct dentry *dentry)
 170 {
 171         struct inode *inode = old_dentry->d_inode;
 172         int error;
 173
 174         lock_ufs(dir->i_sb);
 175         if (inode->i_nlink >= UFS_LINK_MAX) {
 176                 unlock_ufs(dir->i_sb);
 177                 return -EMLINK;
 178         }
 179
 180         inode->i_ctime = CURRENT_TIME_SEC;
 181         inode_inc_link_count(inode);
 182         ihold(inode);
 183
 184         error = ufs_add_nondir(dentry, inode);
 185         unlock_ufs(dir->i_sb);
 186         return error;
 187 }
 188
 189 static int ufs_mkdir(struct inode * dir, struct dentry * dentry, int mode)
 190 {
 191         struct inode * inode;
 192         int err = -EMLINK;
 193
 194         if (dir->i_nlink >= UFS_LINK_MAX)
 195                 goto out;
 196
 197         lock_ufs(dir->i_sb);
 198         inode_inc_link_count(dir);
 199
 200         inode = ufs_new_inode(dir, S_IFDIR|mode);
 201         err = PTR_ERR(inode);
 202         if (IS_ERR(inode))
 203                 goto out_dir;
 204
 205         inode->i_op = &ufs_dir_inode_operations;
 206         inode->i_fop = &ufs_dir_operations;
 207         inode->i_mapping->a_ops = &ufs_aops;
 208
 209         inode_inc_link_count(inode);
 210
 211         err = ufs_make_empty(inode, dir);
 212         if (err)
 213                 goto out_fail;
 214
 215         err = ufs_add_link(dentry, inode);
 216         if (err)
 217                 goto out_fail;
 218         unlock_ufs(dir->i_sb);
 219
 220         d_instantiate(dentry, inode);
 221 out:
 222         return err;
 223
 224 out_fail:
 225         inode_dec_link_count(inode);
 226         inode_dec_link_count(inode);
 227         iput (inode);
 228 out_dir:
 229         inode_dec_link_count(dir);
 230         unlock_ufs(dir->i_sb);
 231         goto out;
 232 }
 233
 234 static int ufs_unlink(struct inode *dir, struct dentry *dentry)
 235 {
 236         struct inode * inode = dentry->d_inode;
 237         struct ufs_dir_entry *de;
 238         struct page *page;
 239         int err = -ENOENT;
 240
 241         de = ufs_find_entry(dir, &dentry->d_name, &page);
 242         if (!de)
 243                 goto out;
 244
 245         err = ufs_delete_entry(dir, de, page);
 246         if (err)
 247                 goto out;
 248
 249         inode->i_ctime = dir->i_ctime;
 250         inode_dec_link_count(inode);
 251         err = 0;
 252 out:
 253         return err;
 254 }
 255
 256 static int ufs_rmdir (struct inode * dir, struct dentry *dentry)
 257 {
 258         struct inode * inode = dentry->d_inode;
 259         int err= -ENOTEMPTY;
 260
 261         dentry_unhash(dentry);
 262
 263         lock_ufs(dir->i_sb);
 264         if (ufs_empty_dir (inode)) {
 265                 err = ufs_unlink(dir, dentry);
 266                 if (!err) {
 267                         inode->i_size = 0;
 268                         inode_dec_link_count(inode);
 269                         inode_dec_link_count(dir);
 270                 }
 271         }
 272         unlock_ufs(dir->i_sb);
 273         return err;
 274 }
 275
 276 static int ufs_rename(struct inode *old_dir, struct dentry *old_dentry,
 277                       struct inode *new_dir, struct dentry *new_dentry)
 278 {
 279         struct inode *old_inode = old_dentry->d_inode;
 280         struct inode *new_inode = new_dentry->d_inode;
 281         struct page *dir_page = NULL;
 282         struct ufs_dir_entry * dir_de = NULL;
 283         struct page *old_page;
 284         struct ufs_dir_entry *old_de;
 285         int err = -ENOENT;
 286
 287         if (new_inode && S_ISDIR(new_inode->i_mode))
 288                 dentry_unhash(new_dentry);
 289
 290         old_de = ufs_find_entry(old_dir, &old_dentry->d_name, &old_page);
 291         if (!old_de)
 292                 goto out;
 293
 294         if (S_ISDIR(old_inode->i_mode)) {
 295                 err = -EIO;
 296                 dir_de = ufs_dotdot(old_inode, &dir_page);
 297                 if (!dir_de)
 298                         goto out_old;
 299         }
 300
 301         if (new_inode) {
 302                 struct page *new_page;
 303                 struct ufs_dir_entry *new_de;
 304
 305                 err = -ENOTEMPTY;
 306                 if (dir_de && !ufs_empty_dir(new_inode))
 307                         goto out_dir;
 308
 309                 err = -ENOENT;
 310                 new_de = ufs_find_entry(new_dir, &new_dentry->d_name, &new_page);
 311                 if (!new_de)
 312                         goto out_dir;
 313                 ufs_set_link(new_dir, new_de, new_page, old_inode);
 314                 new_inode->i_ctime = CURRENT_TIME_SEC;
 315                 if (dir_de)
 316                         drop_nlink(new_inode);
 317                 inode_dec_link_count(new_inode);
 318         } else {
 319                 if (dir_de) {
 320                         err = -EMLINK;
 321                         if (new_dir->i_nlink >= UFS_LINK_MAX)
 322                                 goto out_dir;
 323                 }
 324                 err = ufs_add_link(new_dentry, old_inode);
 325                 if (err)
 326                         goto out_dir;
 327                 if (dir_de)
 328                         inode_inc_link_count(new_dir);
 329         }
 330
 331         /*
 332          * Like most other Unix systems, set the ctime for inodes on a
 333          * rename.
 334          */
 335         old_inode->i_ctime = CURRENT_TIME_SEC;
 336
 337         ufs_delete_entry(old_dir, old_de, old_page);
 338         mark_inode_dirty(old_inode);
 339
 340         if (dir_de) {
 341                 ufs_set_link(old_inode, dir_de, dir_page, new_dir);
 342                 inode_dec_link_count(old_dir);
 343         }
 344         return 0;
 345
 346
 347 out_dir:
 348         if (dir_de) {
 349                 kunmap(dir_page);
 350                 page_cache_release(dir_page);
 351         }
 352 out_old:
 353         kunmap(old_page);
 354         page_cache_release(old_page);
 355 out:
 356         return err;
 357 }
 358
 359 const struct inode_operations ufs_dir_inode_operations = {
 360         .create         = ufs_create,
 361         .lookup         = ufs_lookup,
 362         .link           = ufs_link,
 363         .unlink         = ufs_unlink,
 364         .symlink        = ufs_symlink,
 365         .mkdir          = ufs_mkdir,
 366         .rmdir          = ufs_rmdir,
 367         .mknod          = ufs_mknod,
 368         .rename         = ufs_rename,
 369 };