linux/fs/exofs/namei.c
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   1/*
   2 * Copyright (C) 2005, 2006
   3 * Avishay Traeger (avishay@gmail.com)
   4 * Copyright (C) 2008, 2009
   5 * Boaz Harrosh <ooo@electrozaur.com>
   6 *
   7 * Copyrights for code taken from ext2:
   8 *     Copyright (C) 1992, 1993, 1994, 1995
   9 *     Remy Card (card@masi.ibp.fr)
  10 *     Laboratoire MASI - Institut Blaise Pascal
  11 *     Universite Pierre et Marie Curie (Paris VI)
  12 *     from
  13 *     linux/fs/minix/inode.c
  14 *     Copyright (C) 1991, 1992  Linus Torvalds
  15 *
  16 * This file is part of exofs.
  17 *
  18 * exofs is free software; you can redistribute it and/or modify
  19 * it under the terms of the GNU General Public License as published by
  20 * the Free Software Foundation.  Since it is based on ext2, and the only
  21 * valid version of GPL for the Linux kernel is version 2, the only valid
  22 * version of GPL for exofs is version 2.
  23 *
  24 * exofs is distributed in the hope that it will be useful,
  25 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  26 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  27 * GNU General Public License for more details.
  28 *
  29 * You should have received a copy of the GNU General Public License
  30 * along with exofs; if not, write to the Free Software
  31 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  32 */
  33
  34#include "exofs.h"
  35
  36static inline int exofs_add_nondir(struct dentry *dentry, struct inode *inode)
  37{
  38        int err = exofs_add_link(dentry, inode);
  39        if (!err) {
  40                d_instantiate(dentry, inode);
  41                return 0;
  42        }
  43        inode_dec_link_count(inode);
  44        iput(inode);
  45        return err;
  46}
  47
  48static struct dentry *exofs_lookup(struct inode *dir, struct dentry *dentry,
  49                                   unsigned int flags)
  50{
  51        struct inode *inode;
  52        ino_t ino;
  53
  54        if (dentry->d_name.len > EXOFS_NAME_LEN)
  55                return ERR_PTR(-ENAMETOOLONG);
  56
  57        ino = exofs_inode_by_name(dir, dentry);
  58        inode = ino ? exofs_iget(dir->i_sb, ino) : NULL;
  59        return d_splice_alias(inode, dentry);
  60}
  61
  62static int exofs_create(struct inode *dir, struct dentry *dentry, umode_t mode,
  63                         bool excl)
  64{
  65        struct inode *inode = exofs_new_inode(dir, mode);
  66        int err = PTR_ERR(inode);
  67        if (!IS_ERR(inode)) {
  68                inode->i_op = &exofs_file_inode_operations;
  69                inode->i_fop = &exofs_file_operations;
  70                inode->i_mapping->a_ops = &exofs_aops;
  71                mark_inode_dirty(inode);
  72                err = exofs_add_nondir(dentry, inode);
  73        }
  74        return err;
  75}
  76
  77static int exofs_mknod(struct inode *dir, struct dentry *dentry, umode_t mode,
  78                       dev_t rdev)
  79{
  80        struct inode *inode;
  81        int err;
  82
  83        inode = exofs_new_inode(dir, mode);
  84        err = PTR_ERR(inode);
  85        if (!IS_ERR(inode)) {
  86                init_special_inode(inode, inode->i_mode, rdev);
  87                mark_inode_dirty(inode);
  88                err = exofs_add_nondir(dentry, inode);
  89        }
  90        return err;
  91}
  92
  93static int exofs_symlink(struct inode *dir, struct dentry *dentry,
  94                          const char *symname)
  95{
  96        struct super_block *sb = dir->i_sb;
  97        int err = -ENAMETOOLONG;
  98        unsigned l = strlen(symname)+1;
  99        struct inode *inode;
 100        struct exofs_i_info *oi;
 101
 102        if (l > sb->s_blocksize)
 103                goto out;
 104
 105        inode = exofs_new_inode(dir, S_IFLNK | S_IRWXUGO);
 106        err = PTR_ERR(inode);
 107        if (IS_ERR(inode))
 108                goto out;
 109
 110        oi = exofs_i(inode);
 111        if (l > sizeof(oi->i_data)) {
 112                /* slow symlink */
 113                inode->i_op = &page_symlink_inode_operations;
 114                inode_nohighmem(inode);
 115                inode->i_mapping->a_ops = &exofs_aops;
 116                memset(oi->i_data, 0, sizeof(oi->i_data));
 117
 118                err = page_symlink(inode, symname, l);
 119                if (err)
 120                        goto out_fail;
 121        } else {
 122                /* fast symlink */
 123                inode->i_op = &simple_symlink_inode_operations;
 124                inode->i_link = (char *)oi->i_data;
 125                memcpy(oi->i_data, symname, l);
 126                inode->i_size = l-1;
 127        }
 128        mark_inode_dirty(inode);
 129
 130        err = exofs_add_nondir(dentry, inode);
 131out:
 132        return err;
 133
 134out_fail:
 135        inode_dec_link_count(inode);
 136        iput(inode);
 137        goto out;
 138}
 139
 140static int exofs_link(struct dentry *old_dentry, struct inode *dir,
 141                struct dentry *dentry)
 142{
 143        struct inode *inode = d_inode(old_dentry);
 144
 145        inode->i_ctime = CURRENT_TIME;
 146        inode_inc_link_count(inode);
 147        ihold(inode);
 148
 149        return exofs_add_nondir(dentry, inode);
 150}
 151
 152static int exofs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
 153{
 154        struct inode *inode;
 155        int err;
 156
 157        inode_inc_link_count(dir);
 158
 159        inode = exofs_new_inode(dir, S_IFDIR | mode);
 160        err = PTR_ERR(inode);
 161        if (IS_ERR(inode))
 162                goto out_dir;
 163
 164        inode->i_op = &exofs_dir_inode_operations;
 165        inode->i_fop = &exofs_dir_operations;
 166        inode->i_mapping->a_ops = &exofs_aops;
 167
 168        inode_inc_link_count(inode);
 169
 170        err = exofs_make_empty(inode, dir);
 171        if (err)
 172                goto out_fail;
 173
 174        err = exofs_add_link(dentry, inode);
 175        if (err)
 176                goto out_fail;
 177
 178        d_instantiate(dentry, inode);
 179out:
 180        return err;
 181
 182out_fail:
 183        inode_dec_link_count(inode);
 184        inode_dec_link_count(inode);
 185        iput(inode);
 186out_dir:
 187        inode_dec_link_count(dir);
 188        goto out;
 189}
 190
 191static int exofs_unlink(struct inode *dir, struct dentry *dentry)
 192{
 193        struct inode *inode = d_inode(dentry);
 194        struct exofs_dir_entry *de;
 195        struct page *page;
 196        int err = -ENOENT;
 197
 198        de = exofs_find_entry(dir, dentry, &page);
 199        if (!de)
 200                goto out;
 201
 202        err = exofs_delete_entry(de, page);
 203        if (err)
 204                goto out;
 205
 206        inode->i_ctime = dir->i_ctime;
 207        inode_dec_link_count(inode);
 208        err = 0;
 209out:
 210        return err;
 211}
 212
 213static int exofs_rmdir(struct inode *dir, struct dentry *dentry)
 214{
 215        struct inode *inode = d_inode(dentry);
 216        int err = -ENOTEMPTY;
 217
 218        if (exofs_empty_dir(inode)) {
 219                err = exofs_unlink(dir, dentry);
 220                if (!err) {
 221                        inode->i_size = 0;
 222                        inode_dec_link_count(inode);
 223                        inode_dec_link_count(dir);
 224                }
 225        }
 226        return err;
 227}
 228
 229static int exofs_rename(struct inode *old_dir, struct dentry *old_dentry,
 230                struct inode *new_dir, struct dentry *new_dentry)
 231{
 232        struct inode *old_inode = d_inode(old_dentry);
 233        struct inode *new_inode = d_inode(new_dentry);
 234        struct page *dir_page = NULL;
 235        struct exofs_dir_entry *dir_de = NULL;
 236        struct page *old_page;
 237        struct exofs_dir_entry *old_de;
 238        int err = -ENOENT;
 239
 240        old_de = exofs_find_entry(old_dir, old_dentry, &old_page);
 241        if (!old_de)
 242                goto out;
 243
 244        if (S_ISDIR(old_inode->i_mode)) {
 245                err = -EIO;
 246                dir_de = exofs_dotdot(old_inode, &dir_page);
 247                if (!dir_de)
 248                        goto out_old;
 249        }
 250
 251        if (new_inode) {
 252                struct page *new_page;
 253                struct exofs_dir_entry *new_de;
 254
 255                err = -ENOTEMPTY;
 256                if (dir_de && !exofs_empty_dir(new_inode))
 257                        goto out_dir;
 258
 259                err = -ENOENT;
 260                new_de = exofs_find_entry(new_dir, new_dentry, &new_page);
 261                if (!new_de)
 262                        goto out_dir;
 263                err = exofs_set_link(new_dir, new_de, new_page, old_inode);
 264                new_inode->i_ctime = CURRENT_TIME;
 265                if (dir_de)
 266                        drop_nlink(new_inode);
 267                inode_dec_link_count(new_inode);
 268                if (err)
 269                        goto out_dir;
 270        } else {
 271                err = exofs_add_link(new_dentry, old_inode);
 272                if (err)
 273                        goto out_dir;
 274                if (dir_de)
 275                        inode_inc_link_count(new_dir);
 276        }
 277
 278        old_inode->i_ctime = CURRENT_TIME;
 279
 280        exofs_delete_entry(old_de, old_page);
 281        mark_inode_dirty(old_inode);
 282
 283        if (dir_de) {
 284                err = exofs_set_link(old_inode, dir_de, dir_page, new_dir);
 285                inode_dec_link_count(old_dir);
 286                if (err)
 287                        goto out_dir;
 288        }
 289        return 0;
 290
 291
 292out_dir:
 293        if (dir_de) {
 294                kunmap(dir_page);
 295                put_page(dir_page);
 296        }
 297out_old:
 298        kunmap(old_page);
 299        put_page(old_page);
 300out:
 301        return err;
 302}
 303
 304const struct inode_operations exofs_dir_inode_operations = {
 305        .create         = exofs_create,
 306        .lookup         = exofs_lookup,
 307        .link           = exofs_link,
 308        .unlink         = exofs_unlink,
 309        .symlink        = exofs_symlink,
 310        .mkdir          = exofs_mkdir,
 311        .rmdir          = exofs_rmdir,
 312        .mknod          = exofs_mknod,
 313        .rename         = exofs_rename,
 314        .setattr        = exofs_setattr,
 315};
 316
 317const struct inode_operations exofs_special_inode_operations = {
 318        .setattr        = exofs_setattr,
 319};
 320