fs/reiserfs/dir.c

   1 /*
   2  * Copyright 2000 by Hans Reiser, licensing governed by reiserfs/README
   3  */
   4
   5 #include <linux/string.h>
   6 #include <linux/errno.h>
   7 #include <linux/fs.h>
   8 #include <linux/reiserfs_fs.h>
   9 #include <linux/stat.h>
  10 #include <linux/buffer_head.h>
  11 #include <linux/slab.h>
  12 #include <asm/uaccess.h>
  13
  14 extern const struct reiserfs_key MIN_KEY;
  15
  16 static int reiserfs_readdir(struct file *, void *, filldir_t);
  17 static int reiserfs_dir_fsync(struct file *filp, int datasync);
  18
  19 const struct file_operations reiserfs_dir_operations = {
  20         .llseek = generic_file_llseek,
  21         .read = generic_read_dir,
  22         .readdir = reiserfs_readdir,
  23         .fsync = reiserfs_dir_fsync,
  24         .unlocked_ioctl = reiserfs_ioctl,
  25 #ifdef CONFIG_COMPAT
  26         .compat_ioctl = reiserfs_compat_ioctl,
  27 #endif
  28 };
  29
  30 static int reiserfs_dir_fsync(struct file *filp, int datasync)
  31 {
  32         struct inode *inode = filp->f_mapping->host;
  33         int err;
  34         reiserfs_write_lock(inode->i_sb);
  35         err = reiserfs_commit_for_inode(inode);
  36         reiserfs_write_unlock(inode->i_sb);
  37         if (err < 0)
  38                 return err;
  39         return 0;
  40 }
  41
  42 #define store_ih(where,what) copy_item_head (where, what)
  43
  44 static inline bool is_privroot_deh(struct dentry *dir,
  45                                    struct reiserfs_de_head *deh)
  46 {
  47         struct dentry *privroot = REISERFS_SB(dir->d_sb)->priv_root;
  48         return (dir == dir->d_parent && privroot->d_inode &&
  49                 deh->deh_objectid == INODE_PKEY(privroot->d_inode)->k_objectid);
  50 }
  51
  52 int reiserfs_readdir_dentry(struct dentry *dentry, void *dirent,
  53                            filldir_t filldir, loff_t *pos)
  54 {
  55         struct inode *inode = dentry->d_inode;
  56         struct cpu_key pos_key; /* key of current position in the directory (key of directory entry) */
  57         INITIALIZE_PATH(path_to_entry);
  58         struct buffer_head *bh;
  59         int item_num, entry_num;
  60         const struct reiserfs_key *rkey;
  61         struct item_head *ih, tmp_ih;
  62         int search_res;
  63         char *local_buf;
  64         loff_t next_pos;
  65         char small_buf[32];     /* avoid kmalloc if we can */
  66         struct reiserfs_dir_entry de;
  67         int ret = 0;
  68
  69         reiserfs_write_lock(inode->i_sb);
  70
  71         reiserfs_check_lock_depth(inode->i_sb, "readdir");
  72
  73         /* form key for search the next directory entry using f_pos field of
  74            file structure */
  75         make_cpu_key(&pos_key, inode, *pos ?: DOT_OFFSET, TYPE_DIRENTRY, 3);
  76         next_pos = cpu_key_k_offset(&pos_key);
  77
  78         path_to_entry.reada = PATH_READA;
  79         while (1) {
  80               research:
  81                 /* search the directory item, containing entry with specified key */
  82                 search_res =
  83                     search_by_entry_key(inode->i_sb, &pos_key, &path_to_entry,
  84                                         &de);
  85                 if (search_res == IO_ERROR) {
  86                         // FIXME: we could just skip part of directory which could
  87                         // not be read
  88                         ret = -EIO;
  89                         goto out;
  90                 }
  91                 entry_num = de.de_entry_num;
  92                 bh = de.de_bh;
  93                 item_num = de.de_item_num;
  94                 ih = de.de_ih;
  95                 store_ih(&tmp_ih, ih);
  96
  97                 /* we must have found item, that is item of this directory, */
  98                 RFALSE(COMP_SHORT_KEYS(&(ih->ih_key), &pos_key),
  99                        "vs-9000: found item %h does not match to dir we readdir %K",
 100                        ih, &pos_key);
 101                 RFALSE(item_num > B_NR_ITEMS(bh) - 1,
 102                        "vs-9005 item_num == %d, item amount == %d",
 103                        item_num, B_NR_ITEMS(bh));
 104
 105                 /* and entry must be not more than number of entries in the item */
 106                 RFALSE(I_ENTRY_COUNT(ih) < entry_num,
 107                        "vs-9010: entry number is too big %d (%d)",
 108                        entry_num, I_ENTRY_COUNT(ih));
 109
 110                 if (search_res == POSITION_FOUND
 111                     || entry_num < I_ENTRY_COUNT(ih)) {
 112                         /* go through all entries in the directory item beginning from the entry, that has been found */
 113                         struct reiserfs_de_head *deh =
 114                             B_I_DEH(bh, ih) + entry_num;
 115
 116                         for (; entry_num < I_ENTRY_COUNT(ih);
 117                              entry_num++, deh++) {
 118                                 int d_reclen;
 119                                 char *d_name;
 120                                 off_t d_off;
 121                                 ino_t d_ino;
 122
 123                                 if (!de_visible(deh))
 124                                         /* it is hidden entry */
 125                                         continue;
 126                                 d_reclen = entry_length(bh, ih, entry_num);
 127                                 d_name = B_I_DEH_ENTRY_FILE_NAME(bh, ih, deh);
 128
 129                                 if (d_reclen <= 0 ||
 130                                     d_name + d_reclen > bh->b_data + bh->b_size) {
 131                                         /* There is corrupted data in entry,
 132                                          * We'd better stop here */
 133                                         pathrelse(&path_to_entry);
 134                                         ret = -EIO;
 135                                         goto out;
 136                                 }
 137
 138                                 if (!d_name[d_reclen - 1])
 139                                         d_reclen = strlen(d_name);
 140
 141                                 if (d_reclen >
 142                                     REISERFS_MAX_NAME(inode->i_sb->
 143                                                       s_blocksize)) {
 144                                         /* too big to send back to VFS */
 145                                         continue;
 146                                 }
 147
 148                                 /* Ignore the .reiserfs_priv entry */
 149                                 if (is_privroot_deh(dentry, deh))
 150                                         continue;
 151
 152                                 d_off = deh_offset(deh);
 153                                 *pos = d_off;
 154                                 d_ino = deh_objectid(deh);
 155                                 if (d_reclen <= 32) {
 156                                         local_buf = small_buf;
 157                                 } else {
 158                                         local_buf = kmalloc(d_reclen,
 159                                                             GFP_NOFS);
 160                                         if (!local_buf) {
 161                                                 pathrelse(&path_to_entry);
 162                                                 ret = -ENOMEM;
 163                                                 goto out;
 164                                         }
 165                                         if (item_moved(&tmp_ih, &path_to_entry)) {
 166                                                 kfree(local_buf);
 167                                                 goto research;
 168                                         }
 169                                 }
 170                                 // Note, that we copy name to user space via temporary
 171                                 // buffer (local_buf) because filldir will block if
 172                                 // user space buffer is swapped out. At that time
 173                                 // entry can move to somewhere else
 174                                 memcpy(local_buf, d_name, d_reclen);
 175
 176                                 /*
 177                                  * Since filldir might sleep, we can release
 178                                  * the write lock here for other waiters
 179                                  */
 180                                 reiserfs_write_unlock(inode->i_sb);
 181                                 if (filldir
 182                                     (dirent, local_buf, d_reclen, d_off, d_ino,
 183                                      DT_UNKNOWN) < 0) {
 184                                         reiserfs_write_lock(inode->i_sb);
 185                                         if (local_buf != small_buf) {
 186                                                 kfree(local_buf);
 187                                         }
 188                                         goto end;
 189                                 }
 190                                 reiserfs_write_lock(inode->i_sb);
 191                                 if (local_buf != small_buf) {
 192                                         kfree(local_buf);
 193                                 }
 194                                 // next entry should be looked for with such offset
 195                                 next_pos = deh_offset(deh) + 1;
 196
 197                                 if (item_moved(&tmp_ih, &path_to_entry)) {
 198                                         goto research;
 199                                 }
 200                         }       /* for */
 201                 }
 202
 203                 if (item_num != B_NR_ITEMS(bh) - 1)
 204                         // end of directory has been reached
 205                         goto end;
 206
 207                 /* item we went through is last item of node. Using right
 208                    delimiting key check is it directory end */
 209                 rkey = get_rkey(&path_to_entry, inode->i_sb);
 210                 if (!comp_le_keys(rkey, &MIN_KEY)) {
 211                         /* set pos_key to key, that is the smallest and greater
 212                            that key of the last entry in the item */
 213                         set_cpu_key_k_offset(&pos_key, next_pos);
 214                         continue;
 215                 }
 216
 217                 if (COMP_SHORT_KEYS(rkey, &pos_key)) {
 218                         // end of directory has been reached
 219                         goto end;
 220                 }
 221
 222                 /* directory continues in the right neighboring block */
 223                 set_cpu_key_k_offset(&pos_key,
 224                                      le_key_k_offset(KEY_FORMAT_3_5, rkey));
 225
 226         }                       /* while */
 227
 228 end:
 229         *pos = next_pos;
 230         pathrelse(&path_to_entry);
 231         reiserfs_check_path(&path_to_entry);
 232 out:
 233         reiserfs_write_unlock(inode->i_sb);
 234         return ret;
 235 }
 236
 237 static int reiserfs_readdir(struct file *file, void *dirent, filldir_t filldir)
 238 {
 239         struct dentry *dentry = file->f_path.dentry;
 240         return reiserfs_readdir_dentry(dentry, dirent, filldir, &file->f_pos);
 241 }
 242
 243 /* compose directory item containing "." and ".." entries (entries are
 244    not aligned to 4 byte boundary) */
 245 /* the last four params are LE */
 246 void make_empty_dir_item_v1(char *body, __le32 dirid, __le32 objid,
 247                             __le32 par_dirid, __le32 par_objid)
 248 {
 249         struct reiserfs_de_head *deh;
 250
 251         memset(body, 0, EMPTY_DIR_SIZE_V1);
 252         deh = (struct reiserfs_de_head *)body;
 253
 254         /* direntry header of "." */
 255         put_deh_offset(&(deh[0]), DOT_OFFSET);
 256         /* these two are from make_le_item_head, and are are LE */
 257         deh[0].deh_dir_id = dirid;
 258         deh[0].deh_objectid = objid;
 259         deh[0].deh_state = 0;   /* Endian safe if 0 */
 260         put_deh_location(&(deh[0]), EMPTY_DIR_SIZE_V1 - strlen("."));
 261         mark_de_visible(&(deh[0]));
 262
 263         /* direntry header of ".." */
 264         put_deh_offset(&(deh[1]), DOT_DOT_OFFSET);
 265         /* key of ".." for the root directory */
 266         /* these two are from the inode, and are are LE */
 267         deh[1].deh_dir_id = par_dirid;
 268         deh[1].deh_objectid = par_objid;
 269         deh[1].deh_state = 0;   /* Endian safe if 0 */
 270         put_deh_location(&(deh[1]), deh_location(&(deh[0])) - strlen(".."));
 271         mark_de_visible(&(deh[1]));
 272
 273         /* copy ".." and "." */
 274         memcpy(body + deh_location(&(deh[0])), ".", 1);
 275         memcpy(body + deh_location(&(deh[1])), "..", 2);
 276 }
 277
 278 /* compose directory item containing "." and ".." entries */
 279 void make_empty_dir_item(char *body, __le32 dirid, __le32 objid,
 280                          __le32 par_dirid, __le32 par_objid)
 281 {
 282         struct reiserfs_de_head *deh;
 283
 284         memset(body, 0, EMPTY_DIR_SIZE);
 285         deh = (struct reiserfs_de_head *)body;
 286
 287         /* direntry header of "." */
 288         put_deh_offset(&(deh[0]), DOT_OFFSET);
 289         /* these two are from make_le_item_head, and are are LE */
 290         deh[0].deh_dir_id = dirid;
 291         deh[0].deh_objectid = objid;
 292         deh[0].deh_state = 0;   /* Endian safe if 0 */
 293         put_deh_location(&(deh[0]), EMPTY_DIR_SIZE - ROUND_UP(strlen(".")));
 294         mark_de_visible(&(deh[0]));
 295
 296         /* direntry header of ".." */
 297         put_deh_offset(&(deh[1]), DOT_DOT_OFFSET);
 298         /* key of ".." for the root directory */
 299         /* these two are from the inode, and are are LE */
 300         deh[1].deh_dir_id = par_dirid;
 301         deh[1].deh_objectid = par_objid;
 302         deh[1].deh_state = 0;   /* Endian safe if 0 */
 303         put_deh_location(&(deh[1]),
 304                          deh_location(&(deh[0])) - ROUND_UP(strlen("..")));
 305         mark_de_visible(&(deh[1]));
 306
 307         /* copy ".." and "." */
 308         memcpy(body + deh_location(&(deh[0])), ".", 1);
 309         memcpy(body + deh_location(&(deh[1])), "..", 2);
 310 }