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 <bharrosh@panasas.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        if (!new_valid_dev(rdev))
  84                return -EINVAL;
  85
  86        inode = exofs_new_inode(dir, mode);
  87        err = PTR_ERR(inode);
  88        if (!IS_ERR(inode)) {
  89                init_special_inode(inode, inode->i_mode, rdev);
  90                mark_inode_dirty(inode);
  91                err = exofs_add_nondir(dentry, inode);
  92        }
  93        return err;
  94}
  95
  96static int exofs_symlink(struct inode *dir, struct dentry *dentry,
  97                          const char *symname)
  98{
  99        struct super_block *sb = dir->i_sb;
 100        int err = -ENAMETOOLONG;
 101        unsigned l = strlen(symname)+1;
 102        struct inode *inode;
 103        struct exofs_i_info *oi;
 104
 105        if (l > sb->s_blocksize)
 106                goto out;
 107
 108        inode = exofs_new_inode(dir, S_IFLNK | S_IRWXUGO);
 109        err = PTR_ERR(inode);
 110        if (IS_ERR(inode))
 111                goto out;
 112
 113        oi = exofs_i(inode);
 114        if (l > sizeof(oi->i_data)) {
 115                /* slow symlink */
 116                inode->i_op = &exofs_symlink_inode_operations;
 117                inode->i_mapping->a_ops = &exofs_aops;
 118                memset(oi->i_data, 0, sizeof(oi->i_data));
 119
 120                err = page_symlink(inode, symname, l);
 121                if (err)
 122                        goto out_fail;
 123        } else {
 124                /* fast symlink */
 125                inode->i_op = &exofs_fast_symlink_inode_operations;
 126                memcpy(oi->i_data, symname, l);
 127                inode->i_size = l-1;
 128        }
 129        mark_inode_dirty(inode);
 130
 131        err = exofs_add_nondir(dentry, inode);
 132out:
 133        return err;
 134
 135out_fail:
 136        inode_dec_link_count(inode);
 137        iput(inode);
 138        goto out;
 139}
 140
 141static int exofs_link(struct dentry *old_dentry, struct inode *dir,
 142                struct dentry *dentry)
 143{
 144        struct inode *inode = old_dentry->d_inode;
 145
 146        inode->i_ctime = CURRENT_TIME;
 147        inode_inc_link_count(inode);
 148        ihold(inode);
 149
 150        return exofs_add_nondir(dentry, inode);
 151}
 152
 153static int exofs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
 154{
 155        struct inode *inode;
 156        int err;
 157
 158        inode_inc_link_count(dir);
 159
 160        inode = exofs_new_inode(dir, S_IFDIR | mode);
 161        err = PTR_ERR(inode);
 162        if (IS_ERR(inode))
 163                goto out_dir;
 164
 165        inode->i_op = &exofs_dir_inode_operations;
 166        inode->i_fop = &exofs_dir_operations;
 167        inode->i_mapping->a_ops = &exofs_aops;
 168
 169        inode_inc_link_count(inode);
 170
 171        err = exofs_make_empty(inode, dir);
 172        if (err)
 173                goto out_fail;
 174
 175        err = exofs_add_link(dentry, inode);
 176        if (err)
 177                goto out_fail;
 178
 179        d_instantiate(dentry, inode);
 180out:
 181        return err;
 182
 183out_fail:
 184        inode_dec_link_count(inode);
 185        inode_dec_link_count(inode);
 186        iput(inode);
 187out_dir:
 188        inode_dec_link_count(dir);
 189        goto out;
 190}
 191
 192static int exofs_unlink(struct inode *dir, struct dentry *dentry)
 193{
 194        struct inode *inode = dentry->d_inode;
 195        struct exofs_dir_entry *de;
 196        struct page *page;
 197        int err = -ENOENT;
 198
 199        de = exofs_find_entry(dir, dentry, &page);
 200        if (!de)
 201                goto out;
 202
 203        err = exofs_delete_entry(de, page);
 204        if (err)
 205                goto out;
 206
 207        inode->i_ctime = dir->i_ctime;
 208        inode_dec_link_count(inode);
 209        err = 0;
 210out:
 211        return err;
 212}
 213
 214static int exofs_rmdir(struct inode *dir, struct dentry *dentry)
 215{
 216        struct inode *inode = dentry->d_inode;
 217        int err = -ENOTEMPTY;
 218
 219        if (exofs_empty_dir(inode)) {
 220                err = exofs_unlink(dir, dentry);
 221                if (!err) {
 222                        inode->i_size = 0;
 223                        inode_dec_link_count(inode);
 224                        inode_dec_link_count(dir);
 225                }
 226        }
 227        return err;
 228}
 229
 230static int exofs_rename(struct inode *old_dir, struct dentry *old_dentry,
 231                struct inode *new_dir, struct dentry *new_dentry)
 232{
 233        struct inode *old_inode = old_dentry->d_inode;
 234        struct inode *new_inode = new_dentry->d_inode;
 235        struct page *dir_page = NULL;
 236        struct exofs_dir_entry *dir_de = NULL;
 237        struct page *old_page;
 238        struct exofs_dir_entry *old_de;
 239        int err = -ENOENT;
 240
 241        old_de = exofs_find_entry(old_dir, old_dentry, &old_page);
 242        if (!old_de)
 243                goto out;
 244
 245        if (S_ISDIR(old_inode->i_mode)) {
 246                err = -EIO;
 247                dir_de = exofs_dotdot(old_inode, &dir_page);
 248                if (!dir_de)
 249                        goto out_old;
 250        }
 251
 252        if (new_inode) {
 253                struct page *new_page;
 254                struct exofs_dir_entry *new_de;
 255
 256                err = -ENOTEMPTY;
 257                if (dir_de && !exofs_empty_dir(new_inode))
 258                        goto out_dir;
 259
 260                err = -ENOENT;
 261                new_de = exofs_find_entry(new_dir, new_dentry, &new_page);
 262                if (!new_de)
 263                        goto out_dir;
 264                err = exofs_set_link(new_dir, new_de, new_page, old_inode);
 265                new_inode->i_ctime = CURRENT_TIME;
 266                if (dir_de)
 267                        drop_nlink(new_inode);
 268                inode_dec_link_count(new_inode);
 269                if (err)
 270                        goto out_dir;
 271        } else {
 272                err = exofs_add_link(new_dentry, old_inode);
 273                if (err)
 274                        goto out_dir;
 275                if (dir_de)
 276                        inode_inc_link_count(new_dir);
 277        }
 278
 279        old_inode->i_ctime = CURRENT_TIME;
 280
 281        exofs_delete_entry(old_de, old_page);
 282        mark_inode_dirty(old_inode);
 283
 284        if (dir_de) {
 285                err = exofs_set_link(old_inode, dir_de, dir_page, new_dir);
 286                inode_dec_link_count(old_dir);
 287                if (err)
 288                        goto out_dir;
 289        }
 290        return 0;
 291
 292
 293out_dir:
 294        if (dir_de) {
 295                kunmap(dir_page);
 296                page_cache_release(dir_page);
 297        }
 298out_old:
 299        kunmap(old_page);
 300        page_cache_release(old_page);
 301out:
 302        return err;
 303}
 304
 305const struct inode_operations exofs_dir_inode_operations = {
 306        .create         = exofs_create,
 307        .lookup         = exofs_lookup,
 308        .link           = exofs_link,
 309        .unlink         = exofs_unlink,
 310        .symlink        = exofs_symlink,
 311        .mkdir          = exofs_mkdir,
 312        .rmdir          = exofs_rmdir,
 313        .mknod          = exofs_mknod,
 314        .rename         = exofs_rename,
 315        .setattr        = exofs_setattr,
 316};
 317
 318const struct inode_operations exofs_special_inode_operations = {
 319        .setattr        = exofs_setattr,
 320};
 321
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