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 inode * dir, struct dentry * dentry, umode_t mode,
  73                 bool excl)
  74 {
  75         struct inode *inode;
  76
  77         inode = ufs_new_inode(dir, mode);
  78         if (IS_ERR(inode))
  79                 return PTR_ERR(inode);
  80
  81         inode->i_op = &ufs_file_inode_operations;
  82         inode->i_fop = &ufs_file_operations;
  83         inode->i_mapping->a_ops = &ufs_aops;
  84         mark_inode_dirty(inode);
  85         return ufs_add_nondir(dentry, inode);
  86 }
  87
  88 static int ufs_mknod(struct inode *dir, struct dentry *dentry, umode_t mode, dev_t rdev)
  89 {
  90         struct inode *inode;
  91         int err;
  92
  93         if (!old_valid_dev(rdev))
  94                 return -EINVAL;
  95
  96         inode = ufs_new_inode(dir, mode);
  97         err = PTR_ERR(inode);
  98         if (!IS_ERR(inode)) {
  99                 init_special_inode(inode, mode, rdev);
 100                 ufs_set_inode_dev(inode->i_sb, UFS_I(inode), rdev);
 101                 mark_inode_dirty(inode);
 102                 err = ufs_add_nondir(dentry, inode);
 103         }
 104         return err;
 105 }
 106
 107 static int ufs_symlink (struct inode * dir, struct dentry * dentry,
 108         const char * symname)
 109 {
 110         struct super_block * sb = dir->i_sb;
 111         int err;
 112         unsigned l = strlen(symname)+1;
 113         struct inode * inode;
 114
 115         if (l > sb->s_blocksize)
 116                 return -ENAMETOOLONG;
 117
 118         inode = ufs_new_inode(dir, S_IFLNK | S_IRWXUGO);
 119         err = PTR_ERR(inode);
 120         if (IS_ERR(inode))
 121                 return err;
 122
 123         if (l > UFS_SB(sb)->s_uspi->s_maxsymlinklen) {
 124                 /* slow symlink */
 125                 inode->i_op = &page_symlink_inode_operations;
 126                 inode_nohighmem(inode);
 127                 inode->i_mapping->a_ops = &ufs_aops;
 128                 err = page_symlink(inode, symname, l);
 129                 if (err)
 130                         goto out_fail;
 131         } else {
 132                 /* fast symlink */
 133                 inode->i_op = &simple_symlink_inode_operations;
 134                 inode->i_link = (char *)UFS_I(inode)->i_u1.i_symlink;
 135                 memcpy(inode->i_link, symname, l);
 136                 inode->i_size = l-1;
 137         }
 138         mark_inode_dirty(inode);
 139
 140         return ufs_add_nondir(dentry, inode);
 141
 142 out_fail:
 143         inode_dec_link_count(inode);
 144         discard_new_inode(inode);
 145         return err;
 146 }
 147
 148 static int ufs_link (struct dentry * old_dentry, struct inode * dir,
 149         struct dentry *dentry)
 150 {
 151         struct inode *inode = d_inode(old_dentry);
 152         int error;
 153
 154         inode->i_ctime = current_time(inode);
 155         inode_inc_link_count(inode);
 156         ihold(inode);
 157
 158         error = ufs_add_link(dentry, inode);
 159         if (error) {
 160                 inode_dec_link_count(inode);
 161                 iput(inode);
 162         } else
 163                 d_instantiate(dentry, inode);
 164         return error;
 165 }
 166
 167 static int ufs_mkdir(struct inode * dir, struct dentry * dentry, umode_t mode)
 168 {
 169         struct inode * inode;
 170         int err;
 171
 172         inode_inc_link_count(dir);
 173
 174         inode = ufs_new_inode(dir, S_IFDIR|mode);
 175         err = PTR_ERR(inode);
 176         if (IS_ERR(inode))
 177                 goto out_dir;
 178
 179         inode->i_op = &ufs_dir_inode_operations;
 180         inode->i_fop = &ufs_dir_operations;
 181         inode->i_mapping->a_ops = &ufs_aops;
 182
 183         inode_inc_link_count(inode);
 184
 185         err = ufs_make_empty(inode, dir);
 186         if (err)
 187                 goto out_fail;
 188
 189         err = ufs_add_link(dentry, inode);
 190         if (err)
 191                 goto out_fail;
 192
 193         d_instantiate_new(dentry, inode);
 194         return 0;
 195
 196 out_fail:
 197         inode_dec_link_count(inode);
 198         inode_dec_link_count(inode);
 199         discard_new_inode(inode);
 200 out_dir:
 201         inode_dec_link_count(dir);
 202         return err;
 203 }
 204
 205 static int ufs_unlink(struct inode *dir, struct dentry *dentry)
 206 {
 207         struct inode * inode = d_inode(dentry);
 208         struct ufs_dir_entry *de;
 209         struct page *page;
 210         int err = -ENOENT;
 211
 212         de = ufs_find_entry(dir, &dentry->d_name, &page);
 213         if (!de)
 214                 goto out;
 215
 216         err = ufs_delete_entry(dir, de, page);
 217         if (err)
 218                 goto out;
 219
 220         inode->i_ctime = dir->i_ctime;
 221         inode_dec_link_count(inode);
 222         err = 0;
 223 out:
 224         return err;
 225 }
 226
 227 static int ufs_rmdir (struct inode * dir, struct dentry *dentry)
 228 {
 229         struct inode * inode = d_inode(dentry);
 230         int err= -ENOTEMPTY;
 231
 232         if (ufs_empty_dir (inode)) {
 233                 err = ufs_unlink(dir, dentry);
 234                 if (!err) {
 235                         inode->i_size = 0;
 236                         inode_dec_link_count(inode);
 237                         inode_dec_link_count(dir);
 238                 }
 239         }
 240         return err;
 241 }
 242
 243 static int ufs_rename(struct inode *old_dir, struct dentry *old_dentry,
 244                       struct inode *new_dir, struct dentry *new_dentry,
 245                       unsigned int flags)
 246 {
 247         struct inode *old_inode = d_inode(old_dentry);
 248         struct inode *new_inode = d_inode(new_dentry);
 249         struct page *dir_page = NULL;
 250         struct ufs_dir_entry * dir_de = NULL;
 251         struct page *old_page;
 252         struct ufs_dir_entry *old_de;
 253         int err = -ENOENT;
 254
 255         if (flags & ~RENAME_NOREPLACE)
 256                 return -EINVAL;
 257
 258         old_de = ufs_find_entry(old_dir, &old_dentry->d_name, &old_page);
 259         if (!old_de)
 260                 goto out;
 261
 262         if (S_ISDIR(old_inode->i_mode)) {
 263                 err = -EIO;
 264                 dir_de = ufs_dotdot(old_inode, &dir_page);
 265                 if (!dir_de)
 266                         goto out_old;
 267         }
 268
 269         if (new_inode) {
 270                 struct page *new_page;
 271                 struct ufs_dir_entry *new_de;
 272
 273                 err = -ENOTEMPTY;
 274                 if (dir_de && !ufs_empty_dir(new_inode))
 275                         goto out_dir;
 276
 277                 err = -ENOENT;
 278                 new_de = ufs_find_entry(new_dir, &new_dentry->d_name, &new_page);
 279                 if (!new_de)
 280                         goto out_dir;
 281                 ufs_set_link(new_dir, new_de, new_page, old_inode, 1);
 282                 new_inode->i_ctime = current_time(new_inode);
 283                 if (dir_de)
 284                         drop_nlink(new_inode);
 285                 inode_dec_link_count(new_inode);
 286         } else {
 287                 err = ufs_add_link(new_dentry, old_inode);
 288                 if (err)
 289                         goto out_dir;
 290                 if (dir_de)
 291                         inode_inc_link_count(new_dir);
 292         }
 293
 294         /*
 295          * Like most other Unix systems, set the ctime for inodes on a
 296          * rename.
 297          */
 298         old_inode->i_ctime = current_time(old_inode);
 299
 300         ufs_delete_entry(old_dir, old_de, old_page);
 301         mark_inode_dirty(old_inode);
 302
 303         if (dir_de) {
 304                 if (old_dir != new_dir)
 305                         ufs_set_link(old_inode, dir_de, dir_page, new_dir, 0);
 306                 else {
 307                         kunmap(dir_page);
 308                         put_page(dir_page);
 309                 }
 310                 inode_dec_link_count(old_dir);
 311         }
 312         return 0;
 313
 314
 315 out_dir:
 316         if (dir_de) {
 317                 kunmap(dir_page);
 318                 put_page(dir_page);
 319         }
 320 out_old:
 321         kunmap(old_page);
 322         put_page(old_page);
 323 out:
 324         return err;
 325 }
 326
 327 const struct inode_operations ufs_dir_inode_operations = {
 328         .create         = ufs_create,
 329         .lookup         = ufs_lookup,
 330         .link           = ufs_link,
 331         .unlink         = ufs_unlink,
 332         .symlink        = ufs_symlink,
 333         .mkdir          = ufs_mkdir,
 334         .rmdir          = ufs_rmdir,
 335         .mknod          = ufs_mknod,
 336         .rename         = ufs_rename,
 337 };