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 #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         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_kernel();
  96                 err = ufs_add_nondir(dentry, inode);
  97                 unlock_kernel();
  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         inode = ufs_new_inode(dir, mode);
 111         err = PTR_ERR(inode);
 112         if (!IS_ERR(inode)) {
 113                 init_special_inode(inode, mode, rdev);
 114                 ufs_set_inode_dev(inode->i_sb, UFS_I(inode), rdev);
 115                 mark_inode_dirty(inode);
 116                 lock_kernel();
 117                 err = ufs_add_nondir(dentry, inode);
 118                 unlock_kernel();
 119         }
 120         return err;
 121 }
 122
 123 static int ufs_symlink (struct inode * dir, struct dentry * dentry,
 124         const char * symname)
 125 {
 126         struct super_block * sb = dir->i_sb;
 127         int err = -ENAMETOOLONG;
 128         unsigned l = strlen(symname)+1;
 129         struct inode * inode;
 130
 131         if (l > sb->s_blocksize)
 132                 goto out_notlocked;
 133
 134         lock_kernel();
 135         inode = ufs_new_inode(dir, S_IFLNK | S_IRWXUGO);
 136         err = PTR_ERR(inode);
 137         if (IS_ERR(inode))
 138                 goto out;
 139
 140         if (l > UFS_SB(sb)->s_uspi->s_maxsymlinklen) {
 141                 /* slow symlink */
 142                 inode->i_op = &page_symlink_inode_operations;
 143                 inode->i_mapping->a_ops = &ufs_aops;
 144                 err = page_symlink(inode, symname, l);
 145                 if (err)
 146                         goto out_fail;
 147         } else {
 148                 /* fast symlink */
 149                 inode->i_op = &ufs_fast_symlink_inode_operations;
 150                 memcpy(UFS_I(inode)->i_u1.i_symlink, symname, l);
 151                 inode->i_size = l-1;
 152         }
 153         mark_inode_dirty(inode);
 154
 155         err = ufs_add_nondir(dentry, inode);
 156 out:
 157         unlock_kernel();
 158 out_notlocked:
 159         return err;
 160
 161 out_fail:
 162         inode_dec_link_count(inode);
 163         iput(inode);
 164         goto out;
 165 }
 166
 167 static int ufs_link (struct dentry * old_dentry, struct inode * dir,
 168         struct dentry *dentry)
 169 {
 170         struct inode *inode = old_dentry->d_inode;
 171         int error;
 172
 173         lock_kernel();
 174         if (inode->i_nlink >= UFS_LINK_MAX) {
 175                 unlock_kernel();
 176                 return -EMLINK;
 177         }
 178
 179         inode->i_ctime = CURRENT_TIME_SEC;
 180         inode_inc_link_count(inode);
 181         atomic_inc(&inode->i_count);
 182
 183         error = ufs_add_nondir(dentry, inode);
 184         unlock_kernel();
 185         return error;
 186 }
 187
 188 static int ufs_mkdir(struct inode * dir, struct dentry * dentry, int mode)
 189 {
 190         struct inode * inode;
 191         int err = -EMLINK;
 192
 193         if (dir->i_nlink >= UFS_LINK_MAX)
 194                 goto out;
 195
 196         lock_kernel();
 197         inode_inc_link_count(dir);
 198
 199         inode = ufs_new_inode(dir, S_IFDIR|mode);
 200         err = PTR_ERR(inode);
 201         if (IS_ERR(inode))
 202                 goto out_dir;
 203
 204         inode->i_op = &ufs_dir_inode_operations;
 205         inode->i_fop = &ufs_dir_operations;
 206         inode->i_mapping->a_ops = &ufs_aops;
 207
 208         inode_inc_link_count(inode);
 209
 210         err = ufs_make_empty(inode, dir);
 211         if (err)
 212                 goto out_fail;
 213
 214         err = ufs_add_link(dentry, inode);
 215         if (err)
 216                 goto out_fail;
 217         unlock_kernel();
 218
 219         d_instantiate(dentry, inode);
 220 out:
 221         return err;
 222
 223 out_fail:
 224         inode_dec_link_count(inode);
 225         inode_dec_link_count(inode);
 226         iput (inode);
 227 out_dir:
 228         inode_dec_link_count(dir);
 229         unlock_kernel();
 230         goto out;
 231 }
 232
 233 static int ufs_unlink(struct inode *dir, struct dentry *dentry)
 234 {
 235         struct inode * inode = dentry->d_inode;
 236         struct ufs_dir_entry *de;
 237         struct page *page;
 238         int err = -ENOENT;
 239
 240         de = ufs_find_entry(dir, &dentry->d_name, &page);
 241         if (!de)
 242                 goto out;
 243
 244         err = ufs_delete_entry(dir, de, page);
 245         if (err)
 246                 goto out;
 247
 248         inode->i_ctime = dir->i_ctime;
 249         inode_dec_link_count(inode);
 250         err = 0;
 251 out:
 252         return err;
 253 }
 254
 255 static int ufs_rmdir (struct inode * dir, struct dentry *dentry)
 256 {
 257         struct inode * inode = dentry->d_inode;
 258         int err= -ENOTEMPTY;
 259
 260         lock_kernel();
 261         if (ufs_empty_dir (inode)) {
 262                 err = ufs_unlink(dir, dentry);
 263                 if (!err) {
 264                         inode->i_size = 0;
 265                         inode_dec_link_count(inode);
 266                         inode_dec_link_count(dir);
 267                 }
 268         }
 269         unlock_kernel();
 270         return err;
 271 }
 272
 273 static int ufs_rename(struct inode *old_dir, struct dentry *old_dentry,
 274                       struct inode *new_dir, struct dentry *new_dentry)
 275 {
 276         struct inode *old_inode = old_dentry->d_inode;
 277         struct inode *new_inode = new_dentry->d_inode;
 278         struct page *dir_page = NULL;
 279         struct ufs_dir_entry * dir_de = NULL;
 280         struct page *old_page;
 281         struct ufs_dir_entry *old_de;
 282         int err = -ENOENT;
 283
 284         old_de = ufs_find_entry(old_dir, &old_dentry->d_name, &old_page);
 285         if (!old_de)
 286                 goto out;
 287
 288         if (S_ISDIR(old_inode->i_mode)) {
 289                 err = -EIO;
 290                 dir_de = ufs_dotdot(old_inode, &dir_page);
 291                 if (!dir_de)
 292                         goto out_old;
 293         }
 294
 295         if (new_inode) {
 296                 struct page *new_page;
 297                 struct ufs_dir_entry *new_de;
 298
 299                 err = -ENOTEMPTY;
 300                 if (dir_de && !ufs_empty_dir(new_inode))
 301                         goto out_dir;
 302
 303                 err = -ENOENT;
 304                 new_de = ufs_find_entry(new_dir, &new_dentry->d_name, &new_page);
 305                 if (!new_de)
 306                         goto out_dir;
 307                 inode_inc_link_count(old_inode);
 308                 ufs_set_link(new_dir, new_de, new_page, old_inode);
 309                 new_inode->i_ctime = CURRENT_TIME_SEC;
 310                 if (dir_de)
 311                         drop_nlink(new_inode);
 312                 inode_dec_link_count(new_inode);
 313         } else {
 314                 if (dir_de) {
 315                         err = -EMLINK;
 316                         if (new_dir->i_nlink >= UFS_LINK_MAX)
 317                                 goto out_dir;
 318                 }
 319                 inode_inc_link_count(old_inode);
 320                 err = ufs_add_link(new_dentry, old_inode);
 321                 if (err) {
 322                         inode_dec_link_count(old_inode);
 323                         goto out_dir;
 324                 }
 325                 if (dir_de)
 326                         inode_inc_link_count(new_dir);
 327         }
 328
 329         /*
 330          * Like most other Unix systems, set the ctime for inodes on a
 331          * rename.
 332          * inode_dec_link_count() will mark the inode dirty.
 333          */
 334         old_inode->i_ctime = CURRENT_TIME_SEC;
 335
 336         ufs_delete_entry(old_dir, old_de, old_page);
 337         inode_dec_link_count(old_inode);
 338
 339         if (dir_de) {
 340                 ufs_set_link(old_inode, dir_de, dir_page, new_dir);
 341                 inode_dec_link_count(old_dir);
 342         }
 343         return 0;
 344
 345
 346 out_dir:
 347         if (dir_de) {
 348                 kunmap(dir_page);
 349                 page_cache_release(dir_page);
 350         }
 351 out_old:
 352         kunmap(old_page);
 353         page_cache_release(old_page);
 354 out:
 355         return err;
 356 }
 357
 358 const struct inode_operations ufs_dir_inode_operations = {
 359         .create         = ufs_create,
 360         .lookup         = ufs_lookup,
 361         .link           = ufs_link,
 362         .unlink         = ufs_unlink,
 363         .symlink        = ufs_symlink,
 364         .mkdir          = ufs_mkdir,
 365         .rmdir          = ufs_rmdir,
 366         .mknod          = ufs_mknod,
 367         .rename         = ufs_rename,
 368 };