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/ufs_fs.h>
  33 #include <linux/smp_lock.h>
  34 #include "swab.h"       /* will go away - see comment in mknod() */
  35 #include "util.h"
  36
  37 /*
  38 #undef UFS_NAMEI_DEBUG
  39 */
  40 #define UFS_NAMEI_DEBUG
  41
  42 #ifdef UFS_NAMEI_DEBUG
  43 #define UFSD(x) printk("(%s, %d), %s: ", __FILE__, __LINE__, __FUNCTION__); printk x;
  44 #else
  45 #define UFSD(x)
  46 #endif
  47
  48 static inline int ufs_add_nondir(struct dentry *dentry, struct inode *inode)
  49 {
  50         int err = ufs_add_link(dentry, inode);
  51         if (!err) {
  52                 d_instantiate(dentry, inode);
  53                 return 0;
  54         }
  55         inode_dec_link_count(inode);
  56         iput(inode);
  57         return err;
  58 }
  59
  60 static struct dentry *ufs_lookup(struct inode * dir, struct dentry *dentry, struct nameidata *nd)
  61 {
  62         struct inode * inode = NULL;
  63         ino_t ino;
  64
  65         if (dentry->d_name.len > UFS_MAXNAMLEN)
  66                 return ERR_PTR(-ENAMETOOLONG);
  67
  68         lock_kernel();
  69         ino = ufs_inode_by_name(dir, dentry);
  70         if (ino) {
  71                 inode = iget(dir->i_sb, ino);
  72                 if (!inode) {
  73                         unlock_kernel();
  74                         return ERR_PTR(-EACCES);
  75                 }
  76         }
  77         unlock_kernel();
  78         d_add(dentry, inode);
  79         return NULL;
  80 }
  81
  82 /*
  83  * By the time this is called, we already have created
  84  * the directory cache entry for the new file, but it
  85  * is so far negative - it has no inode.
  86  *
  87  * If the create succeeds, we fill in the inode information
  88  * with d_instantiate().
  89  */
  90 static int ufs_create (struct inode * dir, struct dentry * dentry, int mode,
  91                 struct nameidata *nd)
  92 {
  93         struct inode * inode = ufs_new_inode(dir, mode);
  94         int err = PTR_ERR(inode);
  95         if (!IS_ERR(inode)) {
  96                 inode->i_op = &ufs_file_inode_operations;
  97                 inode->i_fop = &ufs_file_operations;
  98                 inode->i_mapping->a_ops = &ufs_aops;
  99                 mark_inode_dirty(inode);
 100                 lock_kernel();
 101                 err = ufs_add_nondir(dentry, inode);
 102                 unlock_kernel();
 103         }
 104         return err;
 105 }
 106
 107 static int ufs_mknod (struct inode * dir, struct dentry *dentry, int mode, dev_t rdev)
 108 {
 109         struct inode *inode;
 110         int err;
 111
 112         if (!old_valid_dev(rdev))
 113                 return -EINVAL;
 114         inode = ufs_new_inode(dir, mode);
 115         err = PTR_ERR(inode);
 116         if (!IS_ERR(inode)) {
 117                 init_special_inode(inode, mode, rdev);
 118                 /* NOTE: that'll go when we get wide dev_t */
 119                 ufs_set_inode_dev(inode->i_sb, UFS_I(inode), rdev);
 120                 mark_inode_dirty(inode);
 121                 lock_kernel();
 122                 err = ufs_add_nondir(dentry, inode);
 123                 unlock_kernel();
 124         }
 125         return err;
 126 }
 127
 128 static int ufs_symlink (struct inode * dir, struct dentry * dentry,
 129         const char * symname)
 130 {
 131         struct super_block * sb = dir->i_sb;
 132         int err = -ENAMETOOLONG;
 133         unsigned l = strlen(symname)+1;
 134         struct inode * inode;
 135
 136         if (l > sb->s_blocksize)
 137                 goto out;
 138
 139         lock_kernel();
 140         inode = ufs_new_inode(dir, S_IFLNK | S_IRWXUGO);
 141         err = PTR_ERR(inode);
 142         if (IS_ERR(inode))
 143                 goto out;
 144
 145         if (l > UFS_SB(sb)->s_uspi->s_maxsymlinklen) {
 146                 /* slow symlink */
 147                 inode->i_op = &page_symlink_inode_operations;
 148                 inode->i_mapping->a_ops = &ufs_aops;
 149                 err = page_symlink(inode, symname, l);
 150                 if (err)
 151                         goto out_fail;
 152         } else {
 153                 /* fast symlink */
 154                 inode->i_op = &ufs_fast_symlink_inode_operations;
 155                 memcpy((char*)&UFS_I(inode)->i_u1.i_data,symname,l);
 156                 inode->i_size = l-1;
 157         }
 158         mark_inode_dirty(inode);
 159
 160         err = ufs_add_nondir(dentry, inode);
 161 out:
 162         unlock_kernel();
 163         return err;
 164
 165 out_fail:
 166         inode_dec_link_count(inode);
 167         iput(inode);
 168         goto out;
 169 }
 170
 171 static int ufs_link (struct dentry * old_dentry, struct inode * dir,
 172         struct dentry *dentry)
 173 {
 174         struct inode *inode = old_dentry->d_inode;
 175         int error;
 176
 177         lock_kernel();
 178         if (inode->i_nlink >= UFS_LINK_MAX) {
 179                 unlock_kernel();
 180                 return -EMLINK;
 181         }
 182
 183         inode->i_ctime = CURRENT_TIME_SEC;
 184         inode_inc_link_count(inode);
 185         atomic_inc(&inode->i_count);
 186
 187         error = ufs_add_nondir(dentry, inode);
 188         unlock_kernel();
 189         return error;
 190 }
 191
 192 static int ufs_mkdir(struct inode * dir, struct dentry * dentry, int mode)
 193 {
 194         struct inode * inode;
 195         int err = -EMLINK;
 196
 197         if (dir->i_nlink >= UFS_LINK_MAX)
 198                 goto out;
 199
 200         lock_kernel();
 201         inode_inc_link_count(dir);
 202
 203         inode = ufs_new_inode(dir, S_IFDIR|mode);
 204         err = PTR_ERR(inode);
 205         if (IS_ERR(inode))
 206                 goto out_dir;
 207
 208         inode->i_op = &ufs_dir_inode_operations;
 209         inode->i_fop = &ufs_dir_operations;
 210         inode->i_mapping->a_ops = &ufs_aops;
 211
 212         inode_inc_link_count(inode);
 213
 214         err = ufs_make_empty(inode, dir);
 215         if (err)
 216                 goto out_fail;
 217
 218         err = ufs_add_link(dentry, inode);
 219         if (err)
 220                 goto out_fail;
 221         unlock_kernel();
 222
 223         d_instantiate(dentry, inode);
 224 out:
 225         return err;
 226
 227 out_fail:
 228         inode_dec_link_count(inode);
 229         inode_dec_link_count(inode);
 230         iput (inode);
 231 out_dir:
 232         inode_dec_link_count(dir);
 233         unlock_kernel();
 234         goto out;
 235 }
 236
 237 static int ufs_unlink(struct inode *dir, struct dentry *dentry)
 238 {
 239         struct inode * inode = dentry->d_inode;
 240         struct ufs_dir_entry *de;
 241         struct page *page;
 242         int err = -ENOENT;
 243
 244         de = ufs_find_entry(dir, dentry, &page);
 245         if (!de)
 246                 goto out;
 247
 248         err = ufs_delete_entry(dir, de, page);
 249         if (err)
 250                 goto out;
 251
 252         inode->i_ctime = dir->i_ctime;
 253         inode_dec_link_count(inode);
 254         err = 0;
 255 out:
 256         return err;
 257 }
 258
 259 static int ufs_rmdir (struct inode * dir, struct dentry *dentry)
 260 {
 261         struct inode * inode = dentry->d_inode;
 262         int err= -ENOTEMPTY;
 263
 264         lock_kernel();
 265         if (ufs_empty_dir (inode)) {
 266                 err = ufs_unlink(dir, dentry);
 267                 if (!err) {
 268                         inode->i_size = 0;
 269                         inode_dec_link_count(inode);
 270                         inode_dec_link_count(dir);
 271                 }
 272         }
 273         unlock_kernel();
 274         return err;
 275 }
 276
 277 static int ufs_rename(struct inode *old_dir, struct dentry *old_dentry,
 278                       struct inode *new_dir, struct dentry *new_dentry)
 279 {
 280         struct inode *old_inode = old_dentry->d_inode;
 281         struct inode *new_inode = new_dentry->d_inode;
 282         struct page *dir_page = NULL;
 283         struct ufs_dir_entry * dir_de = NULL;
 284         struct page *old_page;
 285         struct ufs_dir_entry *old_de;
 286         int err = -ENOENT;
 287
 288         old_de = ufs_find_entry(old_dir, old_dentry, &old_page);
 289         if (!old_de)
 290                 goto out;
 291
 292         if (S_ISDIR(old_inode->i_mode)) {
 293                 err = -EIO;
 294                 dir_de = ufs_dotdot(old_inode, &dir_page);
 295                 if (!dir_de)
 296                         goto out_old;
 297         }
 298
 299         if (new_inode) {
 300                 struct page *new_page;
 301                 struct ufs_dir_entry *new_de;
 302
 303                 err = -ENOTEMPTY;
 304                 if (dir_de && !ufs_empty_dir(new_inode))
 305                         goto out_dir;
 306
 307                 err = -ENOENT;
 308                 new_de = ufs_find_entry(new_dir, new_dentry, &new_page);
 309                 if (!new_de)
 310                         goto out_dir;
 311                 inode_inc_link_count(old_inode);
 312                 ufs_set_link(new_dir, new_de, new_page, old_inode);
 313                 new_inode->i_ctime = CURRENT_TIME_SEC;
 314                 if (dir_de)
 315                         new_inode->i_nlink--;
 316                 inode_dec_link_count(new_inode);
 317         } else {
 318                 if (dir_de) {
 319                         err = -EMLINK;
 320                         if (new_dir->i_nlink >= UFS_LINK_MAX)
 321                                 goto out_dir;
 322                 }
 323                 inode_inc_link_count(old_inode);
 324                 err = ufs_add_link(new_dentry, old_inode);
 325                 if (err) {
 326                         inode_dec_link_count(old_inode);
 327                         goto out_dir;
 328                 }
 329                 if (dir_de)
 330                         inode_inc_link_count(new_dir);
 331         }
 332
 333         /*
 334          * Like most other Unix systems, set the ctime for inodes on a
 335          * rename.
 336          * inode_dec_link_count() will mark the inode dirty.
 337          */
 338         old_inode->i_ctime = CURRENT_TIME_SEC;
 339
 340         ufs_delete_entry(old_dir, old_de, old_page);
 341         inode_dec_link_count(old_inode);
 342
 343         if (dir_de) {
 344                 ufs_set_link(old_inode, dir_de, dir_page, new_dir);
 345                 inode_dec_link_count(old_dir);
 346         }
 347         return 0;
 348
 349
 350 out_dir:
 351         if (dir_de) {
 352                 kunmap(dir_page);
 353                 page_cache_release(dir_page);
 354         }
 355 out_old:
 356         kunmap(old_page);
 357         page_cache_release(old_page);
 358 out:
 359         return err;
 360 }
 361
 362 struct inode_operations ufs_dir_inode_operations = {
 363         .create         = ufs_create,
 364         .lookup         = ufs_lookup,
 365         .link           = ufs_link,
 366         .unlink         = ufs_unlink,
 367         .symlink        = ufs_symlink,
 368         .mkdir          = ufs_mkdir,
 369         .rmdir          = ufs_rmdir,
 370         .mknod          = ufs_mknod,
 371         .rename         = ufs_rename,
 372 };