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                 d_instantiate_new(dentry, inode);
  43                 return 0;
  44         }
  45         inode_dec_link_count(inode);
  46         discard_new_inode(inode);
  47         return err;
  48 }
  49
  50 static struct dentry *ufs_lookup(struct inode * dir, struct dentry *dentry, unsigned int flags)
  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         ino = ufs_inode_by_name(dir, &dentry->d_name);
  59         if (ino)
  60                 inode = ufs_iget(dir->i_sb, ino);
  61         return d_splice_alias(inode, dentry);
  62 }
  63
  64 /*
  65  * By the time this is called, we already have created
  66  * the directory cache entry for the new file, but it
  67  * is so far negative - it has no inode.
  68  *
  69  * If the create succeeds, we fill in the inode information
  70  * with d_instantiate().
  71  */
  72 static int ufs_create (struct mnt_idmap * idmap,
  73                 struct inode * dir, struct dentry * dentry, umode_t mode,
  74                 bool excl)
  75 {
  76         struct inode *inode;
  77
  78         inode = ufs_new_inode(dir, mode);
  79         if (IS_ERR(inode))
  80                 return PTR_ERR(inode);
  81
  82         inode->i_op = &ufs_file_inode_operations;
  83         inode->i_fop = &ufs_file_operations;
  84         inode->i_mapping->a_ops = &ufs_aops;
  85         mark_inode_dirty(inode);
  86         return ufs_add_nondir(dentry, inode);
  87 }
  88
  89 static int ufs_mknod(struct mnt_idmap *idmap, struct inode *dir,
  90                      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 mnt_idmap * idmap, struct inode * dir,
 110         struct dentry * dentry, 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         discard_new_inode(inode);
 147         return err;
 148 }
 149
 150 static int ufs_link (struct dentry * old_dentry, struct inode * dir,
 151         struct dentry *dentry)
 152 {
 153         struct inode *inode = d_inode(old_dentry);
 154         int error;
 155
 156         inode_set_ctime_current(inode);
 157         inode_inc_link_count(inode);
 158         ihold(inode);
 159
 160         error = ufs_add_link(dentry, inode);
 161         if (error) {
 162                 inode_dec_link_count(inode);
 163                 iput(inode);
 164         } else
 165                 d_instantiate(dentry, inode);
 166         return error;
 167 }
 168
 169 static int ufs_mkdir(struct mnt_idmap * idmap, struct inode * dir,
 170         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         d_instantiate_new(dentry, inode);
 197         return 0;
 198
 199 out_fail:
 200         inode_dec_link_count(inode);
 201         inode_dec_link_count(inode);
 202         discard_new_inode(inode);
 203 out_dir:
 204         inode_dec_link_count(dir);
 205         return err;
 206 }
 207
 208 static int ufs_unlink(struct inode *dir, struct dentry *dentry)
 209 {
 210         struct inode * inode = d_inode(dentry);
 211         struct ufs_dir_entry *de;
 212         struct folio *folio;
 213         int err;
 214
 215         de = ufs_find_entry(dir, &dentry->d_name, &folio);
 216         if (!de)
 217                 return -ENOENT;
 218
 219         err = ufs_delete_entry(dir, de, folio);
 220         if (!err) {
 221                 inode_set_ctime_to_ts(inode, inode_get_ctime(dir));
 222                 inode_dec_link_count(inode);
 223         }
 224         folio_release_kmap(folio, de);
 225         return err;
 226 }
 227
 228 static int ufs_rmdir (struct inode * dir, struct dentry *dentry)
 229 {
 230         struct inode * inode = d_inode(dentry);
 231         int err= -ENOTEMPTY;
 232
 233         if (ufs_empty_dir (inode)) {
 234                 err = ufs_unlink(dir, dentry);
 235                 if (!err) {
 236                         inode->i_size = 0;
 237                         inode_dec_link_count(inode);
 238                         inode_dec_link_count(dir);
 239                 }
 240         }
 241         return err;
 242 }
 243
 244 static int ufs_rename(struct mnt_idmap *idmap, struct inode *old_dir,
 245                       struct dentry *old_dentry, struct inode *new_dir,
 246                       struct dentry *new_dentry, unsigned int flags)
 247 {
 248         struct inode *old_inode = d_inode(old_dentry);
 249         struct inode *new_inode = d_inode(new_dentry);
 250         struct folio *dir_folio = NULL;
 251         struct ufs_dir_entry * dir_de = NULL;
 252         struct folio *old_folio;
 253         struct ufs_dir_entry *old_de;
 254         int err;
 255
 256         if (flags & ~RENAME_NOREPLACE)
 257                 return -EINVAL;
 258
 259         old_de = ufs_find_entry(old_dir, &old_dentry->d_name, &old_folio);
 260         if (!old_de)
 261                 return -ENOENT;
 262
 263         if (S_ISDIR(old_inode->i_mode)) {
 264                 err = -EIO;
 265                 dir_de = ufs_dotdot(old_inode, &dir_folio);
 266                 if (!dir_de)
 267                         goto out_old;
 268         }
 269
 270         if (new_inode) {
 271                 struct folio *new_folio;
 272                 struct ufs_dir_entry *new_de;
 273
 274                 err = -ENOTEMPTY;
 275                 if (dir_de && !ufs_empty_dir(new_inode))
 276                         goto out_dir;
 277
 278                 err = -ENOENT;
 279                 new_de = ufs_find_entry(new_dir, &new_dentry->d_name, &new_folio);
 280                 if (!new_de)
 281                         goto out_dir;
 282                 err = ufs_set_link(new_dir, new_de, new_folio, old_inode, 1);
 283                 folio_release_kmap(new_folio, new_de);
 284                 if (err)
 285                         goto out_dir;
 286                 inode_set_ctime_current(new_inode);
 287                 if (dir_de)
 288                         drop_nlink(new_inode);
 289                 inode_dec_link_count(new_inode);
 290         } else {
 291                 err = ufs_add_link(new_dentry, old_inode);
 292                 if (err)
 293                         goto out_dir;
 294                 if (dir_de)
 295                         inode_inc_link_count(new_dir);
 296         }
 297
 298         /*
 299          * Like most other Unix systems, set the ctime for inodes on a
 300          * rename.
 301          */
 302         inode_set_ctime_current(old_inode);
 303         mark_inode_dirty(old_inode);
 304
 305         err = ufs_delete_entry(old_dir, old_de, old_folio);
 306         if (!err && dir_de) {
 307                 if (old_dir != new_dir)
 308                         err = ufs_set_link(old_inode, dir_de, dir_folio,
 309                                            new_dir, 0);
 310                 inode_dec_link_count(old_dir);
 311         }
 312 out_dir:
 313         if (dir_de)
 314                 folio_release_kmap(dir_folio, dir_de);
 315 out_old:
 316         folio_release_kmap(old_folio, old_de);
 317         return err;
 318 }
 319
 320 const struct inode_operations ufs_dir_inode_operations = {
 321         .create         = ufs_create,
 322         .lookup         = ufs_lookup,
 323         .link           = ufs_link,
 324         .unlink         = ufs_unlink,
 325         .symlink        = ufs_symlink,
 326         .mkdir          = ufs_mkdir,
 327         .rmdir          = ufs_rmdir,
 328         .mknod          = ufs_mknod,
 329         .rename         = ufs_rename,
 330 };