linux/fs/sysv/namei.c
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   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
  18static 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
  30static int sysv_hash(const struct dentry *dentry, const struct inode *inode,
  31                struct qstr *qstr)
  32{
  33        /* Truncate the name in place, avoids having to define a compare
  34           function. */
  35        if (qstr->len > SYSV_NAMELEN) {
  36                qstr->len = SYSV_NAMELEN;
  37                qstr->hash = full_name_hash(qstr->name, qstr->len);
  38        }
  39        return 0;
  40}
  41
  42const struct dentry_operations sysv_dentry_operations = {
  43        .d_hash         = sysv_hash,
  44};
  45
  46static struct dentry *sysv_lookup(struct inode * dir, struct dentry * dentry, unsigned int flags)
  47{
  48        struct inode * inode = NULL;
  49        ino_t ino;
  50
  51        if (dentry->d_name.len > SYSV_NAMELEN)
  52                return ERR_PTR(-ENAMETOOLONG);
  53        ino = sysv_inode_by_name(dentry);
  54
  55        if (ino) {
  56                inode = sysv_iget(dir->i_sb, ino);
  57                if (IS_ERR(inode))
  58                        return ERR_CAST(inode);
  59        }
  60        d_add(dentry, inode);
  61        return NULL;
  62}
  63
  64static int sysv_mknod(struct inode * dir, struct dentry * dentry, umode_t mode, dev_t rdev)
  65{
  66        struct inode * inode;
  67        int err;
  68
  69        if (!old_valid_dev(rdev))
  70                return -EINVAL;
  71
  72        inode = sysv_new_inode(dir, mode);
  73        err = PTR_ERR(inode);
  74
  75        if (!IS_ERR(inode)) {
  76                sysv_set_inode(inode, rdev);
  77                mark_inode_dirty(inode);
  78                err = add_nondir(dentry, inode);
  79        }
  80        return err;
  81}
  82
  83static int sysv_create(struct inode * dir, struct dentry * dentry, umode_t mode, bool excl)
  84{
  85        return sysv_mknod(dir, dentry, mode, 0);
  86}
  87
  88static int sysv_symlink(struct inode * dir, struct dentry * dentry, 
  89        const char * symname)
  90{
  91        int err = -ENAMETOOLONG;
  92        int l = strlen(symname)+1;
  93        struct inode * inode;
  94
  95        if (l > dir->i_sb->s_blocksize)
  96                goto out;
  97
  98        inode = sysv_new_inode(dir, S_IFLNK|0777);
  99        err = PTR_ERR(inode);
 100        if (IS_ERR(inode))
 101                goto out;
 102        
 103        sysv_set_inode(inode, 0);
 104        err = page_symlink(inode, symname, l);
 105        if (err)
 106                goto out_fail;
 107
 108        mark_inode_dirty(inode);
 109        err = add_nondir(dentry, inode);
 110out:
 111        return err;
 112
 113out_fail:
 114        inode_dec_link_count(inode);
 115        iput(inode);
 116        goto out;
 117}
 118
 119static int sysv_link(struct dentry * old_dentry, struct inode * dir, 
 120        struct dentry * dentry)
 121{
 122        struct inode *inode = old_dentry->d_inode;
 123
 124        inode->i_ctime = CURRENT_TIME_SEC;
 125        inode_inc_link_count(inode);
 126        ihold(inode);
 127
 128        return add_nondir(dentry, inode);
 129}
 130
 131static int sysv_mkdir(struct inode * dir, struct dentry *dentry, umode_t mode)
 132{
 133        struct inode * inode;
 134        int err;
 135
 136        inode_inc_link_count(dir);
 137
 138        inode = sysv_new_inode(dir, S_IFDIR|mode);
 139        err = PTR_ERR(inode);
 140        if (IS_ERR(inode))
 141                goto out_dir;
 142
 143        sysv_set_inode(inode, 0);
 144
 145        inode_inc_link_count(inode);
 146
 147        err = sysv_make_empty(inode, dir);
 148        if (err)
 149                goto out_fail;
 150
 151        err = sysv_add_link(dentry, inode);
 152        if (err)
 153                goto out_fail;
 154
 155        d_instantiate(dentry, inode);
 156out:
 157        return err;
 158
 159out_fail:
 160        inode_dec_link_count(inode);
 161        inode_dec_link_count(inode);
 162        iput(inode);
 163out_dir:
 164        inode_dec_link_count(dir);
 165        goto out;
 166}
 167
 168static int sysv_unlink(struct inode * dir, struct dentry * dentry)
 169{
 170        struct inode * inode = dentry->d_inode;
 171        struct page * page;
 172        struct sysv_dir_entry * de;
 173        int err = -ENOENT;
 174
 175        de = sysv_find_entry(dentry, &page);
 176        if (!de)
 177                goto out;
 178
 179        err = sysv_delete_entry (de, page);
 180        if (err)
 181                goto out;
 182
 183        inode->i_ctime = dir->i_ctime;
 184        inode_dec_link_count(inode);
 185out:
 186        return err;
 187}
 188
 189static int sysv_rmdir(struct inode * dir, struct dentry * dentry)
 190{
 191        struct inode *inode = dentry->d_inode;
 192        int err = -ENOTEMPTY;
 193
 194        if (sysv_empty_dir(inode)) {
 195                err = sysv_unlink(dir, dentry);
 196                if (!err) {
 197                        inode->i_size = 0;
 198                        inode_dec_link_count(inode);
 199                        inode_dec_link_count(dir);
 200                }
 201        }
 202        return err;
 203}
 204
 205/*
 206 * Anybody can rename anything with this: the permission checks are left to the
 207 * higher-level routines.
 208 */
 209static int sysv_rename(struct inode * old_dir, struct dentry * old_dentry,
 210                  struct inode * new_dir, struct dentry * new_dentry)
 211{
 212        struct inode * old_inode = old_dentry->d_inode;
 213        struct inode * new_inode = new_dentry->d_inode;
 214        struct page * dir_page = NULL;
 215        struct sysv_dir_entry * dir_de = NULL;
 216        struct page * old_page;
 217        struct sysv_dir_entry * old_de;
 218        int err = -ENOENT;
 219
 220        old_de = sysv_find_entry(old_dentry, &old_page);
 221        if (!old_de)
 222                goto out;
 223
 224        if (S_ISDIR(old_inode->i_mode)) {
 225                err = -EIO;
 226                dir_de = sysv_dotdot(old_inode, &dir_page);
 227                if (!dir_de)
 228                        goto out_old;
 229        }
 230
 231        if (new_inode) {
 232                struct page * new_page;
 233                struct sysv_dir_entry * new_de;
 234
 235                err = -ENOTEMPTY;
 236                if (dir_de && !sysv_empty_dir(new_inode))
 237                        goto out_dir;
 238
 239                err = -ENOENT;
 240                new_de = sysv_find_entry(new_dentry, &new_page);
 241                if (!new_de)
 242                        goto out_dir;
 243                sysv_set_link(new_de, new_page, old_inode);
 244                new_inode->i_ctime = CURRENT_TIME_SEC;
 245                if (dir_de)
 246                        drop_nlink(new_inode);
 247                inode_dec_link_count(new_inode);
 248        } else {
 249                err = sysv_add_link(new_dentry, old_inode);
 250                if (err)
 251                        goto out_dir;
 252                if (dir_de)
 253                        inode_inc_link_count(new_dir);
 254        }
 255
 256        sysv_delete_entry(old_de, old_page);
 257        mark_inode_dirty(old_inode);
 258
 259        if (dir_de) {
 260                sysv_set_link(dir_de, dir_page, new_dir);
 261                inode_dec_link_count(old_dir);
 262        }
 263        return 0;
 264
 265out_dir:
 266        if (dir_de) {
 267                kunmap(dir_page);
 268                page_cache_release(dir_page);
 269        }
 270out_old:
 271        kunmap(old_page);
 272        page_cache_release(old_page);
 273out:
 274        return err;
 275}
 276
 277/*
 278 * directories can handle most operations...
 279 */
 280const struct inode_operations sysv_dir_inode_operations = {
 281        .create         = sysv_create,
 282        .lookup         = sysv_lookup,
 283        .link           = sysv_link,
 284        .unlink         = sysv_unlink,
 285        .symlink        = sysv_symlink,
 286        .mkdir          = sysv_mkdir,
 287        .rmdir          = sysv_rmdir,
 288        .mknod          = sysv_mknod,
 289        .rename         = sysv_rename,
 290        .getattr        = sysv_getattr,
 291};
 292
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