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 <[email protected]> based on ext2 code base.
   6  *
   7  * Copyright (C) 1998
   8  * Daniel Pirkl <[email protected]>
   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 ([email protected])
  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 ([email protected]), 1995
  28  */
  29
  30 #include <linux/time.h>
  31 #include <linux/fs.h>
  32 #include <linux/smp_lock.h>
  33
  34 #include "ufs_fs.h"
  35 #include "ufs.h"
  36 #include "util.h"
  37
  38 static inline int ufs_add_nondir(struct dentry *dentry, struct inode *inode)
  39 {
  40         int err = ufs_add_link(dentry, inode);
  41         if (!err) {
  42                 d_instantiate(dentry, inode);
  43                 return 0;
  44         }
  45         inode_dec_link_count(inode);
  46         iput(inode);
  47         return err;
  48 }
  49
  50 static struct dentry *ufs_lookup(struct inode * dir, struct dentry *dentry, struct nameidata *nd)
  51 {
  52         struct inode * inode = NULL;
  53         ino_t ino;
  54
  55         if (dentry->d_name.len > UFS_MAXNAMLEN)
  56                 return ERR_PTR(-ENAMETOOLONG);
  57
  58         lock_kernel();
  59         ino = ufs_inode_by_name(dir, &dentry->d_name);
  60         if (ino) {
  61                 inode = ufs_iget(dir->i_sb, ino);
  62                 if (IS_ERR(inode)) {
  63                         unlock_kernel();
  64                         return ERR_CAST(inode);
  65                 }
  66         }
  67         unlock_kernel();
  68         d_add(dentry, inode);
  69         return NULL;
  70 }
  71
  72 /*
  73  * By the time this is called, we already have created
  74  * the directory cache entry for the new file, but it
  75  * is so far negative - it has no inode.
  76  *
  77  * If the create succeeds, we fill in the inode information
  78  * with d_instantiate().
  79  */
  80 static int ufs_create (struct inode * dir, struct dentry * dentry, int mode,
  81                 struct nameidata *nd)
  82 {
  83         struct inode *inode;
  84         int err;
  85
  86         UFSD("BEGIN\n");
  87
  88         inode = ufs_new_inode(dir, mode);
  89         err = PTR_ERR(inode);
  90
  91         if (!IS_ERR(inode)) {
  92                 inode->i_op = &ufs_file_inode_operations;
  93                 inode->i_fop = &ufs_file_operations;
  94                 inode->i_mapping->a_ops = &ufs_aops;
  95                 mark_inode_dirty(inode);
  96                 lock_kernel();
  97                 err = ufs_add_nondir(dentry, inode);
  98                 unlock_kernel();
  99         }
 100         UFSD("END: err=%d\n", err);
 101         return err;
 102 }
 103
 104 static int ufs_mknod (struct inode * dir, struct dentry *dentry, int mode, dev_t rdev)
 105 {
 106         struct inode *inode;
 107         int err;
 108
 109         if (!old_valid_dev(rdev))
 110                 return -EINVAL;
 111
 112         inode = ufs_new_inode(dir, mode);
 113         err = PTR_ERR(inode);
 114         if (!IS_ERR(inode)) {
 115                 init_special_inode(inode, mode, rdev);
 116                 ufs_set_inode_dev(inode->i_sb, UFS_I(inode), rdev);
 117                 mark_inode_dirty(inode);
 118                 lock_kernel();
 119                 err = ufs_add_nondir(dentry, inode);
 120                 unlock_kernel();
 121         }
 122         return err;
 123 }
 124
 125 static int ufs_symlink (struct inode * dir, struct dentry * dentry,
 126         const char * symname)
 127 {
 128         struct super_block * sb = dir->i_sb;
 129         int err = -ENAMETOOLONG;
 130         unsigned l = strlen(symname)+1;
 131         struct inode * inode;
 132
 133         if (l > sb->s_blocksize)
 134                 goto out_notlocked;
 135
 136         lock_kernel();
 137         inode = ufs_new_inode(dir, S_IFLNK | S_IRWXUGO);
 138         err = PTR_ERR(inode);
 139         if (IS_ERR(inode))
 140                 goto out;
 141
 142         if (l > UFS_SB(sb)->s_uspi->s_maxsymlinklen) {
 143                 /* slow symlink */
 144                 inode->i_op = &ufs_symlink_inode_operations;
 145                 inode->i_mapping->a_ops = &ufs_aops;
 146                 err = page_symlink(inode, symname, l);
 147                 if (err)
 148                         goto out_fail;
 149         } else {
 150                 /* fast symlink */
 151                 inode->i_op = &ufs_fast_symlink_inode_operations;
 152                 memcpy(UFS_I(inode)->i_u1.i_symlink, symname, l);
 153                 inode->i_size = l-1;
 154         }
 155         mark_inode_dirty(inode);
 156
 157         err = ufs_add_nondir(dentry, inode);
 158 out:
 159         unlock_kernel();
 160 out_notlocked:
 161         return err;
 162
 163 out_fail:
 164         inode_dec_link_count(inode);
 165         iput(inode);
 166         goto out;
 167 }
 168
 169 static int ufs_link (struct dentry * old_dentry, struct inode * dir,
 170         struct dentry *dentry)
 171 {
 172         struct inode *inode = old_dentry->d_inode;
 173         int error;
 174
 175         lock_kernel();
 176         if (inode->i_nlink >= UFS_LINK_MAX) {
 177                 unlock_kernel();
 178                 return -EMLINK;
 179         }
 180
 181         inode->i_ctime = CURRENT_TIME_SEC;
 182         inode_inc_link_count(inode);
 183         atomic_inc(&inode->i_count);
 184
 185         error = ufs_add_nondir(dentry, inode);
 186         unlock_kernel();
 187         return error;
 188 }
 189
 190 static int ufs_mkdir(struct inode * dir, struct dentry * dentry, int mode)
 191 {
 192         struct inode * inode;
 193         int err = -EMLINK;
 194
 195         if (dir->i_nlink >= UFS_LINK_MAX)
 196                 goto out;
 197
 198         lock_kernel();
 199         inode_inc_link_count(dir);
 200
 201         inode = ufs_new_inode(dir, S_IFDIR|mode);
 202         err = PTR_ERR(inode);
 203         if (IS_ERR(inode))
 204                 goto out_dir;
 205
 206         inode->i_op = &ufs_dir_inode_operations;
 207         inode->i_fop = &ufs_dir_operations;
 208         inode->i_mapping->a_ops = &ufs_aops;
 209
 210         inode_inc_link_count(inode);
 211
 212         err = ufs_make_empty(inode, dir);
 213         if (err)
 214                 goto out_fail;
 215
 216         err = ufs_add_link(dentry, inode);
 217         if (err)
 218                 goto out_fail;
 219         unlock_kernel();
 220
 221         d_instantiate(dentry, inode);
 222 out:
 223         return err;
 224
 225 out_fail:
 226         inode_dec_link_count(inode);
 227         inode_dec_link_count(inode);
 228         iput (inode);
 229 out_dir:
 230         inode_dec_link_count(dir);
 231         unlock_kernel();
 232         goto out;
 233 }
 234
 235 static int ufs_unlink(struct inode *dir, struct dentry *dentry)
 236 {
 237         struct inode * inode = dentry->d_inode;
 238         struct ufs_dir_entry *de;
 239         struct page *page;
 240         int err = -ENOENT;
 241
 242         de = ufs_find_entry(dir, &dentry->d_name, &page);
 243         if (!de)
 244                 goto out;
 245
 246         err = ufs_delete_entry(dir, de, page);
 247         if (err)
 248                 goto out;
 249
 250         inode->i_ctime = dir->i_ctime;
 251         inode_dec_link_count(inode);
 252         err = 0;
 253 out:
 254         return err;
 255 }
 256
 257 static int ufs_rmdir (struct inode * dir, struct dentry *dentry)
 258 {
 259         struct inode * inode = dentry->d_inode;
 260         int err= -ENOTEMPTY;
 261
 262         lock_kernel();
 263         if (ufs_empty_dir (inode)) {
 264                 err = ufs_unlink(dir, dentry);
 265                 if (!err) {
 266                         inode->i_size = 0;
 267                         inode_dec_link_count(inode);
 268                         inode_dec_link_count(dir);
 269                 }
 270         }
 271         unlock_kernel();
 272         return err;
 273 }
 274
 275 static int ufs_rename(struct inode *old_dir, struct dentry *old_dentry,
 276                       struct inode *new_dir, struct dentry *new_dentry)
 277 {
 278         struct inode *old_inode = old_dentry->d_inode;
 279         struct inode *new_inode = new_dentry->d_inode;
 280         struct page *dir_page = NULL;
 281         struct ufs_dir_entry * dir_de = NULL;
 282         struct page *old_page;
 283         struct ufs_dir_entry *old_de;
 284         int err = -ENOENT;
 285
 286         old_de = ufs_find_entry(old_dir, &old_dentry->d_name, &old_page);
 287         if (!old_de)
 288                 goto out;
 289
 290         if (S_ISDIR(old_inode->i_mode)) {
 291                 err = -EIO;
 292                 dir_de = ufs_dotdot(old_inode, &dir_page);
 293                 if (!dir_de)
 294                         goto out_old;
 295         }
 296
 297         if (new_inode) {
 298                 struct page *new_page;
 299                 struct ufs_dir_entry *new_de;
 300
 301                 err = -ENOTEMPTY;
 302                 if (dir_de && !ufs_empty_dir(new_inode))
 303                         goto out_dir;
 304
 305                 err = -ENOENT;
 306                 new_de = ufs_find_entry(new_dir, &new_dentry->d_name, &new_page);
 307                 if (!new_de)
 308                         goto out_dir;
 309                 inode_inc_link_count(old_inode);
 310                 ufs_set_link(new_dir, new_de, new_page, old_inode);
 311                 new_inode->i_ctime = CURRENT_TIME_SEC;
 312                 if (dir_de)
 313                         drop_nlink(new_inode);
 314                 inode_dec_link_count(new_inode);
 315         } else {
 316                 if (dir_de) {
 317                         err = -EMLINK;
 318                         if (new_dir->i_nlink >= UFS_LINK_MAX)
 319                                 goto out_dir;
 320                 }
 321                 inode_inc_link_count(old_inode);
 322                 err = ufs_add_link(new_dentry, old_inode);
 323                 if (err) {
 324                         inode_dec_link_count(old_inode);
 325                         goto out_dir;
 326                 }
 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          * inode_dec_link_count() will mark the inode dirty.
 335          */
 336         old_inode->i_ctime = CURRENT_TIME_SEC;
 337
 338         ufs_delete_entry(old_dir, old_de, old_page);
 339         inode_dec_link_count(old_inode);
 340
 341         if (dir_de) {
 342                 ufs_set_link(old_inode, dir_de, dir_page, new_dir);
 343                 inode_dec_link_count(old_dir);
 344         }
 345         return 0;
 346
 347
 348 out_dir:
 349         if (dir_de) {
 350                 kunmap(dir_page);
 351                 page_cache_release(dir_page);
 352         }
 353 out_old:
 354         kunmap(old_page);
 355         page_cache_release(old_page);
 356 out:
 357         return err;
 358 }
 359
 360 const struct inode_operations ufs_dir_inode_operations = {
 361         .create         = ufs_create,
 362         .lookup         = ufs_lookup,
 363         .link           = ufs_link,
 364         .unlink         = ufs_unlink,
 365         .symlink        = ufs_symlink,
 366         .mkdir          = ufs_mkdir,
 367         .rmdir          = ufs_rmdir,
 368         .mknod          = ufs_mknod,
 369         .rename         = ufs_rename,
 370 };