fs/sysv/namei.c

   1 /*
   2  *  linux/fs/sysv/namei.c
   3  *
   4  *  minix/namei.c
   5  *  Copyright (C) 1991, 1992  Linus Torvalds
   6  *
   7  *  coh/namei.c
   8  *  Copyright (C) 1993  Pascal Haible, Bruno Haible
   9  *
  10  *  sysv/namei.c
  11  *  Copyright (C) 1993  Bruno Haible
  12  *  Copyright (C) 1997, 1998  Krzysztof G. Baranowski
  13  */
  14
  15 #include <linux/pagemap.h>
  16 #include "sysv.h"
  17
  18 static int add_nondir(struct dentry *dentry, struct inode *inode)
  19 {
  20         int err = sysv_add_link(dentry, inode);
  21         if (!err) {
  22                 d_instantiate(dentry, inode);
  23                 return 0;
  24         }
  25         inode_dec_link_count(inode);
  26         iput(inode);
  27         return err;
  28 }
  29
  30 static int sysv_hash(const struct dentry *dentry, struct qstr *qstr)
  31 {
  32         /* Truncate the name in place, avoids having to define a compare
  33            function. */
  34         if (qstr->len > SYSV_NAMELEN) {
  35                 qstr->len = SYSV_NAMELEN;
  36                 qstr->hash = full_name_hash(qstr->name, qstr->len);
  37         }
  38         return 0;
  39 }
  40
  41 const struct dentry_operations sysv_dentry_operations = {
  42         .d_hash         = sysv_hash,
  43 };
  44
  45 static struct dentry *sysv_lookup(struct inode * dir, struct dentry * dentry, unsigned int flags)
  46 {
  47         struct inode * inode = NULL;
  48         ino_t ino;
  49
  50         if (dentry->d_name.len > SYSV_NAMELEN)
  51                 return ERR_PTR(-ENAMETOOLONG);
  52         ino = sysv_inode_by_name(dentry);
  53
  54         if (ino) {
  55                 inode = sysv_iget(dir->i_sb, ino);
  56                 if (IS_ERR(inode))
  57                         return ERR_CAST(inode);
  58         }
  59         d_add(dentry, inode);
  60         return NULL;
  61 }
  62
  63 static int sysv_mknod(struct inode * dir, struct dentry * dentry, umode_t mode, dev_t rdev)
  64 {
  65         struct inode * inode;
  66         int err;
  67
  68         if (!old_valid_dev(rdev))
  69                 return -EINVAL;
  70
  71         inode = sysv_new_inode(dir, mode);
  72         err = PTR_ERR(inode);
  73
  74         if (!IS_ERR(inode)) {
  75                 sysv_set_inode(inode, rdev);
  76                 mark_inode_dirty(inode);
  77                 err = add_nondir(dentry, inode);
  78         }
  79         return err;
  80 }
  81
  82 static int sysv_create(struct inode * dir, struct dentry * dentry, umode_t mode, bool excl)
  83 {
  84         return sysv_mknod(dir, dentry, mode, 0);
  85 }
  86
  87 static int sysv_symlink(struct inode * dir, struct dentry * dentry,
  88         const char * symname)
  89 {
  90         int err = -ENAMETOOLONG;
  91         int l = strlen(symname)+1;
  92         struct inode * inode;
  93
  94         if (l > dir->i_sb->s_blocksize)
  95                 goto out;
  96
  97         inode = sysv_new_inode(dir, S_IFLNK|0777);
  98         err = PTR_ERR(inode);
  99         if (IS_ERR(inode))
 100                 goto out;
 101
 102         sysv_set_inode(inode, 0);
 103         err = page_symlink(inode, symname, l);
 104         if (err)
 105                 goto out_fail;
 106
 107         mark_inode_dirty(inode);
 108         err = add_nondir(dentry, inode);
 109 out:
 110         return err;
 111
 112 out_fail:
 113         inode_dec_link_count(inode);
 114         iput(inode);
 115         goto out;
 116 }
 117
 118 static int sysv_link(struct dentry * old_dentry, struct inode * dir,
 119         struct dentry * dentry)
 120 {
 121         struct inode *inode = d_inode(old_dentry);
 122
 123         inode->i_ctime = CURRENT_TIME_SEC;
 124         inode_inc_link_count(inode);
 125         ihold(inode);
 126
 127         return add_nondir(dentry, inode);
 128 }
 129
 130 static int sysv_mkdir(struct inode * dir, struct dentry *dentry, umode_t mode)
 131 {
 132         struct inode * inode;
 133         int err;
 134
 135         inode_inc_link_count(dir);
 136
 137         inode = sysv_new_inode(dir, S_IFDIR|mode);
 138         err = PTR_ERR(inode);
 139         if (IS_ERR(inode))
 140                 goto out_dir;
 141
 142         sysv_set_inode(inode, 0);
 143
 144         inode_inc_link_count(inode);
 145
 146         err = sysv_make_empty(inode, dir);
 147         if (err)
 148                 goto out_fail;
 149
 150         err = sysv_add_link(dentry, inode);
 151         if (err)
 152                 goto out_fail;
 153
 154         d_instantiate(dentry, inode);
 155 out:
 156         return err;
 157
 158 out_fail:
 159         inode_dec_link_count(inode);
 160         inode_dec_link_count(inode);
 161         iput(inode);
 162 out_dir:
 163         inode_dec_link_count(dir);
 164         goto out;
 165 }
 166
 167 static int sysv_unlink(struct inode * dir, struct dentry * dentry)
 168 {
 169         struct inode * inode = d_inode(dentry);
 170         struct page * page;
 171         struct sysv_dir_entry * de;
 172         int err = -ENOENT;
 173
 174         de = sysv_find_entry(dentry, &page);
 175         if (!de)
 176                 goto out;
 177
 178         err = sysv_delete_entry (de, page);
 179         if (err)
 180                 goto out;
 181
 182         inode->i_ctime = dir->i_ctime;
 183         inode_dec_link_count(inode);
 184 out:
 185         return err;
 186 }
 187
 188 static int sysv_rmdir(struct inode * dir, struct dentry * dentry)
 189 {
 190         struct inode *inode = d_inode(dentry);
 191         int err = -ENOTEMPTY;
 192
 193         if (sysv_empty_dir(inode)) {
 194                 err = sysv_unlink(dir, dentry);
 195                 if (!err) {
 196                         inode->i_size = 0;
 197                         inode_dec_link_count(inode);
 198                         inode_dec_link_count(dir);
 199                 }
 200         }
 201         return err;
 202 }
 203
 204 /*
 205  * Anybody can rename anything with this: the permission checks are left to the
 206  * higher-level routines.
 207  */
 208 static int sysv_rename(struct inode * old_dir, struct dentry * old_dentry,
 209                   struct inode * new_dir, struct dentry * new_dentry)
 210 {
 211         struct inode * old_inode = d_inode(old_dentry);
 212         struct inode * new_inode = d_inode(new_dentry);
 213         struct page * dir_page = NULL;
 214         struct sysv_dir_entry * dir_de = NULL;
 215         struct page * old_page;
 216         struct sysv_dir_entry * old_de;
 217         int err = -ENOENT;
 218
 219         old_de = sysv_find_entry(old_dentry, &old_page);
 220         if (!old_de)
 221                 goto out;
 222
 223         if (S_ISDIR(old_inode->i_mode)) {
 224                 err = -EIO;
 225                 dir_de = sysv_dotdot(old_inode, &dir_page);
 226                 if (!dir_de)
 227                         goto out_old;
 228         }
 229
 230         if (new_inode) {
 231                 struct page * new_page;
 232                 struct sysv_dir_entry * new_de;
 233
 234                 err = -ENOTEMPTY;
 235                 if (dir_de && !sysv_empty_dir(new_inode))
 236                         goto out_dir;
 237
 238                 err = -ENOENT;
 239                 new_de = sysv_find_entry(new_dentry, &new_page);
 240                 if (!new_de)
 241                         goto out_dir;
 242                 sysv_set_link(new_de, new_page, old_inode);
 243                 new_inode->i_ctime = CURRENT_TIME_SEC;
 244                 if (dir_de)
 245                         drop_nlink(new_inode);
 246                 inode_dec_link_count(new_inode);
 247         } else {
 248                 err = sysv_add_link(new_dentry, old_inode);
 249                 if (err)
 250                         goto out_dir;
 251                 if (dir_de)
 252                         inode_inc_link_count(new_dir);
 253         }
 254
 255         sysv_delete_entry(old_de, old_page);
 256         mark_inode_dirty(old_inode);
 257
 258         if (dir_de) {
 259                 sysv_set_link(dir_de, dir_page, new_dir);
 260                 inode_dec_link_count(old_dir);
 261         }
 262         return 0;
 263
 264 out_dir:
 265         if (dir_de) {
 266                 kunmap(dir_page);
 267                 page_cache_release(dir_page);
 268         }
 269 out_old:
 270         kunmap(old_page);
 271         page_cache_release(old_page);
 272 out:
 273         return err;
 274 }
 275
 276 /*
 277  * directories can handle most operations...
 278  */
 279 const struct inode_operations sysv_dir_inode_operations = {
 280         .create         = sysv_create,
 281         .lookup         = sysv_lookup,
 282         .link           = sysv_link,
 283         .unlink         = sysv_unlink,
 284         .symlink        = sysv_symlink,
 285         .mkdir          = sysv_mkdir,
 286         .rmdir          = sysv_rmdir,
 287         .mknod          = sysv_mknod,
 288         .rename         = sysv_rename,
 289         .getattr        = sysv_getattr,
 290 };