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, struct dentry *dentry,
  18                               int datasync);
  19
  20 const struct file_operations reiserfs_dir_operations = {
  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, struct dentry *dentry,
  31                               int datasync)
  32 {
  33         struct inode *inode = dentry->d_inode;
  34         int err;
  35         reiserfs_write_lock(inode->i_sb);
  36         err = reiserfs_commit_for_inode(inode);
  37         reiserfs_write_unlock(inode->i_sb);
  38         if (err < 0)
  39                 return err;
  40         return 0;
  41 }
  42
  43 #define store_ih(where,what) copy_item_head (where, what)
  44
  45 static inline bool is_privroot_deh(struct dentry *dir,
  46                                    struct reiserfs_de_head *deh)
  47 {
  48         struct dentry *privroot = REISERFS_SB(dir->d_sb)->priv_root;
  49         return (dir == dir->d_parent && privroot->d_inode &&
  50                 deh->deh_objectid == INODE_PKEY(privroot->d_inode)->k_objectid);
  51 }
  52
  53 int reiserfs_readdir_dentry(struct dentry *dentry, void *dirent,
  54                            filldir_t filldir, loff_t *pos)
  55 {
  56         struct inode *inode = dentry->d_inode;
  57         struct cpu_key pos_key; /* key of current position in the directory (key of directory entry) */
  58         INITIALIZE_PATH(path_to_entry);
  59         struct buffer_head *bh;
  60         int item_num, entry_num;
  61         const struct reiserfs_key *rkey;
  62         struct item_head *ih, tmp_ih;
  63         int search_res;
  64         char *local_buf;
  65         loff_t next_pos;
  66         char small_buf[32];     /* avoid kmalloc if we can */
  67         struct reiserfs_dir_entry de;
  68         int ret = 0;
  69
  70         reiserfs_write_lock(inode->i_sb);
  71
  72         reiserfs_check_lock_depth(inode->i_sb, "readdir");
  73
  74         /* form key for search the next directory entry using f_pos field of
  75            file structure */
  76         make_cpu_key(&pos_key, inode, *pos ?: DOT_OFFSET, TYPE_DIRENTRY, 3);
  77         next_pos = cpu_key_k_offset(&pos_key);
  78
  79         path_to_entry.reada = PATH_READA;
  80         while (1) {
  81               research:
  82                 /* search the directory item, containing entry with specified key */
  83                 search_res =
  84                     search_by_entry_key(inode->i_sb, &pos_key, &path_to_entry,
  85                                         &de);
  86                 if (search_res == IO_ERROR) {
  87                         // FIXME: we could just skip part of directory which could
  88                         // not be read
  89                         ret = -EIO;
  90                         goto out;
  91                 }
  92                 entry_num = de.de_entry_num;
  93                 bh = de.de_bh;
  94                 item_num = de.de_item_num;
  95                 ih = de.de_ih;
  96                 store_ih(&tmp_ih, ih);
  97
  98                 /* we must have found item, that is item of this directory, */
  99                 RFALSE(COMP_SHORT_KEYS(&(ih->ih_key), &pos_key),
 100                        "vs-9000: found item %h does not match to dir we readdir %K",
 101                        ih, &pos_key);
 102                 RFALSE(item_num > B_NR_ITEMS(bh) - 1,
 103                        "vs-9005 item_num == %d, item amount == %d",
 104                        item_num, B_NR_ITEMS(bh));
 105
 106                 /* and entry must be not more than number of entries in the item */
 107                 RFALSE(I_ENTRY_COUNT(ih) < entry_num,
 108                        "vs-9010: entry number is too big %d (%d)",
 109                        entry_num, I_ENTRY_COUNT(ih));
 110
 111                 if (search_res == POSITION_FOUND
 112                     || entry_num < I_ENTRY_COUNT(ih)) {
 113                         /* go through all entries in the directory item beginning from the entry, that has been found */
 114                         struct reiserfs_de_head *deh =
 115                             B_I_DEH(bh, ih) + entry_num;
 116
 117                         for (; entry_num < I_ENTRY_COUNT(ih);
 118                              entry_num++, deh++) {
 119                                 int d_reclen;
 120                                 char *d_name;
 121                                 off_t d_off;
 122                                 ino_t d_ino;
 123
 124                                 if (!de_visible(deh))
 125                                         /* it is hidden entry */
 126                                         continue;
 127                                 d_reclen = entry_length(bh, ih, entry_num);
 128                                 d_name = B_I_DEH_ENTRY_FILE_NAME(bh, ih, deh);
 129
 130                                 if (d_reclen <= 0 ||
 131                                     d_name + d_reclen > bh->b_data + bh->b_size) {
 132                                         /* There is corrupted data in entry,
 133                                          * We'd better stop here */
 134                                         pathrelse(&path_to_entry);
 135                                         ret = -EIO;
 136                                         goto out;
 137                                 }
 138
 139                                 if (!d_name[d_reclen - 1])
 140                                         d_reclen = strlen(d_name);
 141
 142                                 if (d_reclen >
 143                                     REISERFS_MAX_NAME(inode->i_sb->
 144                                                       s_blocksize)) {
 145                                         /* too big to send back to VFS */
 146                                         continue;
 147                                 }
 148
 149                                 /* Ignore the .reiserfs_priv entry */
 150                                 if (is_privroot_deh(dentry, deh))
 151                                         continue;
 152
 153                                 d_off = deh_offset(deh);
 154                                 *pos = d_off;
 155                                 d_ino = deh_objectid(deh);
 156                                 if (d_reclen <= 32) {
 157                                         local_buf = small_buf;
 158                                 } else {
 159                                         local_buf = kmalloc(d_reclen,
 160                                                             GFP_NOFS);
 161                                         if (!local_buf) {
 162                                                 pathrelse(&path_to_entry);
 163                                                 ret = -ENOMEM;
 164                                                 goto out;
 165                                         }
 166                                         if (item_moved(&tmp_ih, &path_to_entry)) {
 167                                                 kfree(local_buf);
 168                                                 goto research;
 169                                         }
 170                                 }
 171                                 // Note, that we copy name to user space via temporary
 172                                 // buffer (local_buf) because filldir will block if
 173                                 // user space buffer is swapped out. At that time
 174                                 // entry can move to somewhere else
 175                                 memcpy(local_buf, d_name, d_reclen);
 176
 177                                 /*
 178                                  * Since filldir might sleep, we can release
 179                                  * the write lock here for other waiters
 180                                  */
 181                                 reiserfs_write_unlock(inode->i_sb);
 182                                 if (filldir
 183                                     (dirent, local_buf, d_reclen, d_off, d_ino,
 184                                      DT_UNKNOWN) < 0) {
 185                                         reiserfs_write_lock(inode->i_sb);
 186                                         if (local_buf != small_buf) {
 187                                                 kfree(local_buf);
 188                                         }
 189                                         goto end;
 190                                 }
 191                                 reiserfs_write_lock(inode->i_sb);
 192                                 if (local_buf != small_buf) {
 193                                         kfree(local_buf);
 194                                 }
 195                                 // next entry should be looked for with such offset
 196                                 next_pos = deh_offset(deh) + 1;
 197
 198                                 if (item_moved(&tmp_ih, &path_to_entry)) {
 199                                         goto research;
 200                                 }
 201                         }       /* for */
 202                 }
 203
 204                 if (item_num != B_NR_ITEMS(bh) - 1)
 205                         // end of directory has been reached
 206                         goto end;
 207
 208                 /* item we went through is last item of node. Using right
 209                    delimiting key check is it directory end */
 210                 rkey = get_rkey(&path_to_entry, inode->i_sb);
 211                 if (!comp_le_keys(rkey, &MIN_KEY)) {
 212                         /* set pos_key to key, that is the smallest and greater
 213                            that key of the last entry in the item */
 214                         set_cpu_key_k_offset(&pos_key, next_pos);
 215                         continue;
 216                 }
 217
 218                 if (COMP_SHORT_KEYS(rkey, &pos_key)) {
 219                         // end of directory has been reached
 220                         goto end;
 221                 }
 222
 223                 /* directory continues in the right neighboring block */
 224                 set_cpu_key_k_offset(&pos_key,
 225                                      le_key_k_offset(KEY_FORMAT_3_5, rkey));
 226
 227         }                       /* while */
 228
 229 end:
 230         *pos = next_pos;
 231         pathrelse(&path_to_entry);
 232         reiserfs_check_path(&path_to_entry);
 233 out:
 234         reiserfs_write_unlock(inode->i_sb);
 235         return ret;
 236 }
 237
 238 static int reiserfs_readdir(struct file *file, void *dirent, filldir_t filldir)
 239 {
 240         struct dentry *dentry = file->f_path.dentry;
 241         return reiserfs_readdir_dentry(dentry, dirent, filldir, &file->f_pos);
 242 }
 243
 244 /* compose directory item containing "." and ".." entries (entries are
 245    not aligned to 4 byte boundary) */
 246 /* the last four params are LE */
 247 void make_empty_dir_item_v1(char *body, __le32 dirid, __le32 objid,
 248                             __le32 par_dirid, __le32 par_objid)
 249 {
 250         struct reiserfs_de_head *deh;
 251
 252         memset(body, 0, EMPTY_DIR_SIZE_V1);
 253         deh = (struct reiserfs_de_head *)body;
 254
 255         /* direntry header of "." */
 256         put_deh_offset(&(deh[0]), DOT_OFFSET);
 257         /* these two are from make_le_item_head, and are are LE */
 258         deh[0].deh_dir_id = dirid;
 259         deh[0].deh_objectid = objid;
 260         deh[0].deh_state = 0;   /* Endian safe if 0 */
 261         put_deh_location(&(deh[0]), EMPTY_DIR_SIZE_V1 - strlen("."));
 262         mark_de_visible(&(deh[0]));
 263
 264         /* direntry header of ".." */
 265         put_deh_offset(&(deh[1]), DOT_DOT_OFFSET);
 266         /* key of ".." for the root directory */
 267         /* these two are from the inode, and are are LE */
 268         deh[1].deh_dir_id = par_dirid;
 269         deh[1].deh_objectid = par_objid;
 270         deh[1].deh_state = 0;   /* Endian safe if 0 */
 271         put_deh_location(&(deh[1]), deh_location(&(deh[0])) - strlen(".."));
 272         mark_de_visible(&(deh[1]));
 273
 274         /* copy ".." and "." */
 275         memcpy(body + deh_location(&(deh[0])), ".", 1);
 276         memcpy(body + deh_location(&(deh[1])), "..", 2);
 277 }
 278
 279 /* compose directory item containing "." and ".." entries */
 280 void make_empty_dir_item(char *body, __le32 dirid, __le32 objid,
 281                          __le32 par_dirid, __le32 par_objid)
 282 {
 283         struct reiserfs_de_head *deh;
 284
 285         memset(body, 0, EMPTY_DIR_SIZE);
 286         deh = (struct reiserfs_de_head *)body;
 287
 288         /* direntry header of "." */
 289         put_deh_offset(&(deh[0]), DOT_OFFSET);
 290         /* these two are from make_le_item_head, and are are LE */
 291         deh[0].deh_dir_id = dirid;
 292         deh[0].deh_objectid = objid;
 293         deh[0].deh_state = 0;   /* Endian safe if 0 */
 294         put_deh_location(&(deh[0]), EMPTY_DIR_SIZE - ROUND_UP(strlen(".")));
 295         mark_de_visible(&(deh[0]));
 296
 297         /* direntry header of ".." */
 298         put_deh_offset(&(deh[1]), DOT_DOT_OFFSET);
 299         /* key of ".." for the root directory */
 300         /* these two are from the inode, and are are LE */
 301         deh[1].deh_dir_id = par_dirid;
 302         deh[1].deh_objectid = par_objid;
 303         deh[1].deh_state = 0;   /* Endian safe if 0 */
 304         put_deh_location(&(deh[1]),
 305                          deh_location(&(deh[0])) - ROUND_UP(strlen("..")));
 306         mark_de_visible(&(deh[1]));
 307
 308         /* copy ".." and "." */
 309         memcpy(body + deh_location(&(deh[0])), ".", 1);
 310         memcpy(body + deh_location(&(deh[1])), "..", 2);
 311 }