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         unlock_new_inode(inode);
  47         iput(inode);
  48         return err;
  49 }
  50
  51 static struct dentry *ufs_lookup(struct inode * dir, struct dentry *dentry, unsigned int flags)
  52 {
  53         struct inode * inode = NULL;
  54         ino_t ino;
  55
  56         if (dentry->d_name.len > UFS_MAXNAMLEN)
  57                 return ERR_PTR(-ENAMETOOLONG);
  58
  59         ino = ufs_inode_by_name(dir, &dentry->d_name);
  60         if (ino)
  61                 inode = ufs_iget(dir->i_sb, ino);
  62         return d_splice_alias(inode, dentry);
  63 }
  64
  65 /*
  66  * By the time this is called, we already have created
  67  * the directory cache entry for the new file, but it
  68  * is so far negative - it has no inode.
  69  *
  70  * If the create succeeds, we fill in the inode information
  71  * with d_instantiate().
  72  */
  73 static int ufs_create (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 inode *dir, struct dentry *dentry, umode_t mode, dev_t rdev)
  90 {
  91         struct inode *inode;
  92         int err;
  93
  94         if (!old_valid_dev(rdev))
  95                 return -EINVAL;
  96
  97         inode = ufs_new_inode(dir, mode);
  98         err = PTR_ERR(inode);
  99         if (!IS_ERR(inode)) {
 100                 init_special_inode(inode, mode, rdev);
 101                 ufs_set_inode_dev(inode->i_sb, UFS_I(inode), rdev);
 102                 mark_inode_dirty(inode);
 103                 err = ufs_add_nondir(dentry, inode);
 104         }
 105         return err;
 106 }
 107
 108 static int ufs_symlink (struct inode * dir, struct dentry * dentry,
 109         const char * symname)
 110 {
 111         struct super_block * sb = dir->i_sb;
 112         int err;
 113         unsigned l = strlen(symname)+1;
 114         struct inode * inode;
 115
 116         if (l > sb->s_blocksize)
 117                 return -ENAMETOOLONG;
 118
 119         inode = ufs_new_inode(dir, S_IFLNK | S_IRWXUGO);
 120         err = PTR_ERR(inode);
 121         if (IS_ERR(inode))
 122                 return err;
 123
 124         if (l > UFS_SB(sb)->s_uspi->s_maxsymlinklen) {
 125                 /* slow symlink */
 126                 inode->i_op = &page_symlink_inode_operations;
 127                 inode_nohighmem(inode);
 128                 inode->i_mapping->a_ops = &ufs_aops;
 129                 err = page_symlink(inode, symname, l);
 130                 if (err)
 131                         goto out_fail;
 132         } else {
 133                 /* fast symlink */
 134                 inode->i_op = &simple_symlink_inode_operations;
 135                 inode->i_link = (char *)UFS_I(inode)->i_u1.i_symlink;
 136                 memcpy(inode->i_link, symname, l);
 137                 inode->i_size = l-1;
 138         }
 139         mark_inode_dirty(inode);
 140
 141         return ufs_add_nondir(dentry, inode);
 142
 143 out_fail:
 144         inode_dec_link_count(inode);
 145         unlock_new_inode(inode);
 146         iput(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->i_ctime = current_time(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 inode * dir, struct dentry * dentry, umode_t mode)
 170 {
 171         struct inode * inode;
 172         int err;
 173
 174         inode_inc_link_count(dir);
 175
 176         inode = ufs_new_inode(dir, S_IFDIR|mode);
 177         err = PTR_ERR(inode);
 178         if (IS_ERR(inode))
 179                 goto out_dir;
 180
 181         inode->i_op = &ufs_dir_inode_operations;
 182         inode->i_fop = &ufs_dir_operations;
 183         inode->i_mapping->a_ops = &ufs_aops;
 184
 185         inode_inc_link_count(inode);
 186
 187         err = ufs_make_empty(inode, dir);
 188         if (err)
 189                 goto out_fail;
 190
 191         err = ufs_add_link(dentry, inode);
 192         if (err)
 193                 goto out_fail;
 194
 195         d_instantiate_new(dentry, inode);
 196         return 0;
 197
 198 out_fail:
 199         inode_dec_link_count(inode);
 200         inode_dec_link_count(inode);
 201         unlock_new_inode(inode);
 202         iput (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 page *page;
 213         int err = -ENOENT;
 214
 215         de = ufs_find_entry(dir, &dentry->d_name, &page);
 216         if (!de)
 217                 goto out;
 218
 219         err = ufs_delete_entry(dir, de, page);
 220         if (err)
 221                 goto out;
 222
 223         inode->i_ctime = dir->i_ctime;
 224         inode_dec_link_count(inode);
 225         err = 0;
 226 out:
 227         return err;
 228 }
 229
 230 static int ufs_rmdir (struct inode * dir, struct dentry *dentry)
 231 {
 232         struct inode * inode = d_inode(dentry);
 233         int err= -ENOTEMPTY;
 234
 235         if (ufs_empty_dir (inode)) {
 236                 err = ufs_unlink(dir, dentry);
 237                 if (!err) {
 238                         inode->i_size = 0;
 239                         inode_dec_link_count(inode);
 240                         inode_dec_link_count(dir);
 241                 }
 242         }
 243         return err;
 244 }
 245
 246 static int ufs_rename(struct inode *old_dir, struct dentry *old_dentry,
 247                       struct inode *new_dir, struct dentry *new_dentry,
 248                       unsigned int flags)
 249 {
 250         struct inode *old_inode = d_inode(old_dentry);
 251         struct inode *new_inode = d_inode(new_dentry);
 252         struct page *dir_page = NULL;
 253         struct ufs_dir_entry * dir_de = NULL;
 254         struct page *old_page;
 255         struct ufs_dir_entry *old_de;
 256         int err = -ENOENT;
 257
 258         if (flags & ~RENAME_NOREPLACE)
 259                 return -EINVAL;
 260
 261         old_de = ufs_find_entry(old_dir, &old_dentry->d_name, &old_page);
 262         if (!old_de)
 263                 goto out;
 264
 265         if (S_ISDIR(old_inode->i_mode)) {
 266                 err = -EIO;
 267                 dir_de = ufs_dotdot(old_inode, &dir_page);
 268                 if (!dir_de)
 269                         goto out_old;
 270         }
 271
 272         if (new_inode) {
 273                 struct page *new_page;
 274                 struct ufs_dir_entry *new_de;
 275
 276                 err = -ENOTEMPTY;
 277                 if (dir_de && !ufs_empty_dir(new_inode))
 278                         goto out_dir;
 279
 280                 err = -ENOENT;
 281                 new_de = ufs_find_entry(new_dir, &new_dentry->d_name, &new_page);
 282                 if (!new_de)
 283                         goto out_dir;
 284                 ufs_set_link(new_dir, new_de, new_page, old_inode, 1);
 285                 new_inode->i_ctime = current_time(new_inode);
 286                 if (dir_de)
 287                         drop_nlink(new_inode);
 288                 inode_dec_link_count(new_inode);
 289         } else {
 290                 err = ufs_add_link(new_dentry, old_inode);
 291                 if (err)
 292                         goto out_dir;
 293                 if (dir_de)
 294                         inode_inc_link_count(new_dir);
 295         }
 296
 297         /*
 298          * Like most other Unix systems, set the ctime for inodes on a
 299          * rename.
 300          */
 301         old_inode->i_ctime = current_time(old_inode);
 302
 303         ufs_delete_entry(old_dir, old_de, old_page);
 304         mark_inode_dirty(old_inode);
 305
 306         if (dir_de) {
 307                 if (old_dir != new_dir)
 308                         ufs_set_link(old_inode, dir_de, dir_page, new_dir, 0);
 309                 else {
 310                         kunmap(dir_page);
 311                         put_page(dir_page);
 312                 }
 313                 inode_dec_link_count(old_dir);
 314         }
 315         return 0;
 316
 317
 318 out_dir:
 319         if (dir_de) {
 320                 kunmap(dir_page);
 321                 put_page(dir_page);
 322         }
 323 out_old:
 324         kunmap(old_page);
 325         put_page(old_page);
 326 out:
 327         return err;
 328 }
 329
 330 const struct inode_operations ufs_dir_inode_operations = {
 331         .create         = ufs_create,
 332         .lookup         = ufs_lookup,
 333         .link           = ufs_link,
 334         .unlink         = ufs_unlink,
 335         .symlink        = ufs_symlink,
 336         .mkdir          = ufs_mkdir,
 337         .rmdir          = ufs_rmdir,
 338         .mknod          = ufs_mknod,
 339         .rename         = ufs_rename,
 340 };