fs/ufs/namei.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * linux/fs/ufs/namei.c
   4  *
   5  * Migration to usage of "page cache" on May 2006 by
   6  * Evgeniy Dushistov <dushistov@mail.ru> based on ext2 code base.
   7  *
   8  * Copyright (C) 1998
   9  * Daniel Pirkl <daniel.pirkl@email.cz>
  10  * Charles University, Faculty of Mathematics and Physics
  11  *
  12  *  from
  13  *
  14  *  linux/fs/ext2/namei.c
  15  *
  16  * Copyright (C) 1992, 1993, 1994, 1995
  17  * Remy Card (card@masi.ibp.fr)
  18  * Laboratoire MASI - Institut Blaise Pascal
  19  * Universite Pierre et Marie Curie (Paris VI)
  20  *
  21  *  from
  22  *
  23  *  linux/fs/minix/namei.c
  24  *
  25  *  Copyright (C) 1991, 1992  Linus Torvalds
  26  *
  27  *  Big-endian to little-endian byte-swapping/bitmaps by
  28  *        David S. Miller (davem@caip.rutgers.edu), 1995
  29  */
  30
  31 #include <linux/time.h>
  32 #include <linux/fs.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                 unlock_new_inode(inode);
  43                 d_instantiate(dentry, inode);
  44                 return 0;
  45         }
  46         inode_dec_link_count(inode);
  47         unlock_new_inode(inode);
  48         iput(inode);
  49         return err;
  50 }
  51
  52 static struct dentry *ufs_lookup(struct inode * dir, struct dentry *dentry, unsigned int flags)
  53 {
  54         struct inode * inode = NULL;
  55         ino_t ino;
  56
  57         if (dentry->d_name.len > UFS_MAXNAMLEN)
  58                 return ERR_PTR(-ENAMETOOLONG);
  59
  60         ino = ufs_inode_by_name(dir, &dentry->d_name);
  61         if (ino)
  62                 inode = ufs_iget(dir->i_sb, ino);
  63         return d_splice_alias(inode, dentry);
  64 }
  65
  66 /*
  67  * By the time this is called, we already have created
  68  * the directory cache entry for the new file, but it
  69  * is so far negative - it has no inode.
  70  *
  71  * If the create succeeds, we fill in the inode information
  72  * with d_instantiate().
  73  */
  74 static int ufs_create (struct inode * dir, struct dentry * dentry, umode_t mode,
  75                 bool excl)
  76 {
  77         struct inode *inode;
  78
  79         inode = ufs_new_inode(dir, mode);
  80         if (IS_ERR(inode))
  81                 return PTR_ERR(inode);
  82
  83         inode->i_op = &ufs_file_inode_operations;
  84         inode->i_fop = &ufs_file_operations;
  85         inode->i_mapping->a_ops = &ufs_aops;
  86         mark_inode_dirty(inode);
  87         return ufs_add_nondir(dentry, inode);
  88 }
  89
  90 static int ufs_mknod(struct inode *dir, struct dentry *dentry, umode_t mode, dev_t rdev)
  91 {
  92         struct inode *inode;
  93         int err;
  94
  95         if (!old_valid_dev(rdev))
  96                 return -EINVAL;
  97
  98         inode = ufs_new_inode(dir, mode);
  99         err = PTR_ERR(inode);
 100         if (!IS_ERR(inode)) {
 101                 init_special_inode(inode, mode, rdev);
 102                 ufs_set_inode_dev(inode->i_sb, UFS_I(inode), rdev);
 103                 mark_inode_dirty(inode);
 104                 err = ufs_add_nondir(dentry, inode);
 105         }
 106         return err;
 107 }
 108
 109 static int ufs_symlink (struct inode * dir, struct dentry * dentry,
 110         const char * symname)
 111 {
 112         struct super_block * sb = dir->i_sb;
 113         int err;
 114         unsigned l = strlen(symname)+1;
 115         struct inode * inode;
 116
 117         if (l > sb->s_blocksize)
 118                 return -ENAMETOOLONG;
 119
 120         inode = ufs_new_inode(dir, S_IFLNK | S_IRWXUGO);
 121         err = PTR_ERR(inode);
 122         if (IS_ERR(inode))
 123                 return err;
 124
 125         if (l > UFS_SB(sb)->s_uspi->s_maxsymlinklen) {
 126                 /* slow symlink */
 127                 inode->i_op = &page_symlink_inode_operations;
 128                 inode_nohighmem(inode);
 129                 inode->i_mapping->a_ops = &ufs_aops;
 130                 err = page_symlink(inode, symname, l);
 131                 if (err)
 132                         goto out_fail;
 133         } else {
 134                 /* fast symlink */
 135                 inode->i_op = &simple_symlink_inode_operations;
 136                 inode->i_link = (char *)UFS_I(inode)->i_u1.i_symlink;
 137                 memcpy(inode->i_link, symname, l);
 138                 inode->i_size = l-1;
 139         }
 140         mark_inode_dirty(inode);
 141
 142         return ufs_add_nondir(dentry, inode);
 143
 144 out_fail:
 145         inode_dec_link_count(inode);
 146         unlock_new_inode(inode);
 147         iput(inode);
 148         return err;
 149 }
 150
 151 static int ufs_link (struct dentry * old_dentry, struct inode * dir,
 152         struct dentry *dentry)
 153 {
 154         struct inode *inode = d_inode(old_dentry);
 155         int error;
 156
 157         inode->i_ctime = current_time(inode);
 158         inode_inc_link_count(inode);
 159         ihold(inode);
 160
 161         error = ufs_add_link(dentry, inode);
 162         if (error) {
 163                 inode_dec_link_count(inode);
 164                 iput(inode);
 165         } else
 166                 d_instantiate(dentry, inode);
 167         return error;
 168 }
 169
 170 static int ufs_mkdir(struct inode * dir, struct dentry * dentry, umode_t mode)
 171 {
 172         struct inode * inode;
 173         int err;
 174
 175         inode_inc_link_count(dir);
 176
 177         inode = ufs_new_inode(dir, S_IFDIR|mode);
 178         err = PTR_ERR(inode);
 179         if (IS_ERR(inode))
 180                 goto out_dir;
 181
 182         inode->i_op = &ufs_dir_inode_operations;
 183         inode->i_fop = &ufs_dir_operations;
 184         inode->i_mapping->a_ops = &ufs_aops;
 185
 186         inode_inc_link_count(inode);
 187
 188         err = ufs_make_empty(inode, dir);
 189         if (err)
 190                 goto out_fail;
 191
 192         err = ufs_add_link(dentry, inode);
 193         if (err)
 194                 goto out_fail;
 195
 196         unlock_new_inode(inode);
 197         d_instantiate(dentry, inode);
 198         return 0;
 199
 200 out_fail:
 201         inode_dec_link_count(inode);
 202         inode_dec_link_count(inode);
 203         unlock_new_inode(inode);
 204         iput (inode);
 205 out_dir:
 206         inode_dec_link_count(dir);
 207         return err;
 208 }
 209
 210 static int ufs_unlink(struct inode *dir, struct dentry *dentry)
 211 {
 212         struct inode * inode = d_inode(dentry);
 213         struct ufs_dir_entry *de;
 214         struct page *page;
 215         int err = -ENOENT;
 216
 217         de = ufs_find_entry(dir, &dentry->d_name, &page);
 218         if (!de)
 219                 goto out;
 220
 221         err = ufs_delete_entry(dir, de, page);
 222         if (err)
 223                 goto out;
 224
 225         inode->i_ctime = dir->i_ctime;
 226         inode_dec_link_count(inode);
 227         err = 0;
 228 out:
 229         return err;
 230 }
 231
 232 static int ufs_rmdir (struct inode * dir, struct dentry *dentry)
 233 {
 234         struct inode * inode = d_inode(dentry);
 235         int err= -ENOTEMPTY;
 236
 237         if (ufs_empty_dir (inode)) {
 238                 err = ufs_unlink(dir, dentry);
 239                 if (!err) {
 240                         inode->i_size = 0;
 241                         inode_dec_link_count(inode);
 242                         inode_dec_link_count(dir);
 243                 }
 244         }
 245         return err;
 246 }
 247
 248 static int ufs_rename(struct inode *old_dir, struct dentry *old_dentry,
 249                       struct inode *new_dir, struct dentry *new_dentry,
 250                       unsigned int flags)
 251 {
 252         struct inode *old_inode = d_inode(old_dentry);
 253         struct inode *new_inode = d_inode(new_dentry);
 254         struct page *dir_page = NULL;
 255         struct ufs_dir_entry * dir_de = NULL;
 256         struct page *old_page;
 257         struct ufs_dir_entry *old_de;
 258         int err = -ENOENT;
 259
 260         if (flags & ~RENAME_NOREPLACE)
 261                 return -EINVAL;
 262
 263         old_de = ufs_find_entry(old_dir, &old_dentry->d_name, &old_page);
 264         if (!old_de)
 265                 goto out;
 266
 267         if (S_ISDIR(old_inode->i_mode)) {
 268                 err = -EIO;
 269                 dir_de = ufs_dotdot(old_inode, &dir_page);
 270                 if (!dir_de)
 271                         goto out_old;
 272         }
 273
 274         if (new_inode) {
 275                 struct page *new_page;
 276                 struct ufs_dir_entry *new_de;
 277
 278                 err = -ENOTEMPTY;
 279                 if (dir_de && !ufs_empty_dir(new_inode))
 280                         goto out_dir;
 281
 282                 err = -ENOENT;
 283                 new_de = ufs_find_entry(new_dir, &new_dentry->d_name, &new_page);
 284                 if (!new_de)
 285                         goto out_dir;
 286                 ufs_set_link(new_dir, new_de, new_page, old_inode, 1);
 287                 new_inode->i_ctime = current_time(new_inode);
 288                 if (dir_de)
 289                         drop_nlink(new_inode);
 290                 inode_dec_link_count(new_inode);
 291         } else {
 292                 err = ufs_add_link(new_dentry, old_inode);
 293                 if (err)
 294                         goto out_dir;
 295                 if (dir_de)
 296                         inode_inc_link_count(new_dir);
 297         }
 298
 299         /*
 300          * Like most other Unix systems, set the ctime for inodes on a
 301          * rename.
 302          */
 303         old_inode->i_ctime = current_time(old_inode);
 304
 305         ufs_delete_entry(old_dir, old_de, old_page);
 306         mark_inode_dirty(old_inode);
 307
 308         if (dir_de) {
 309                 if (old_dir != new_dir)
 310                         ufs_set_link(old_inode, dir_de, dir_page, new_dir, 0);
 311                 else {
 312                         kunmap(dir_page);
 313                         put_page(dir_page);
 314                 }
 315                 inode_dec_link_count(old_dir);
 316         }
 317         return 0;
 318
 319
 320 out_dir:
 321         if (dir_de) {
 322                 kunmap(dir_page);
 323                 put_page(dir_page);
 324         }
 325 out_old:
 326         kunmap(old_page);
 327         put_page(old_page);
 328 out:
 329         return err;
 330 }
 331
 332 const struct inode_operations ufs_dir_inode_operations = {
 333         .create         = ufs_create,
 334         .lookup         = ufs_lookup,
 335         .link           = ufs_link,
 336         .unlink         = ufs_unlink,
 337         .symlink        = ufs_symlink,
 338         .mkdir          = ufs_mkdir,
 339         .rmdir          = ufs_rmdir,
 340         .mknod          = ufs_mknod,
 341         .rename         = ufs_rename,
 342 };