git.oblomov.eu Git - linux-2.6/blob - 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 <asm/uaccess.h>
  12
  13 extern const struct reiserfs_key MIN_KEY;
  14
  15 static int reiserfs_readdir(struct file *, void *, filldir_t);
  16 static int reiserfs_dir_fsync(struct file *filp, struct dentry *dentry,
  17                               int datasync);
  18
  19 const struct file_operations reiserfs_dir_operations = {
  20         .read = generic_read_dir,
  21         .readdir = reiserfs_readdir,
  22         .fsync = reiserfs_dir_fsync,
  23         .ioctl = reiserfs_ioctl,
  24 #ifdef CONFIG_COMPAT
  25         .compat_ioctl = reiserfs_compat_ioctl,
  26 #endif
  27 };
  28
  29 static int reiserfs_dir_fsync(struct file *filp, struct dentry *dentry,
  30                               int datasync)
  31 {
  32         struct inode *inode = dentry->d_inode;
  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         int ret = 0;
  48 #ifdef CONFIG_REISERFS_FS_XATTR
  49         struct dentry *privroot = REISERFS_SB(dir->d_sb)->priv_root;
  50         ret = (dir == dir->d_parent && privroot->d_inode &&
  51                deh->deh_objectid == INODE_PKEY(privroot->d_inode)->k_objectid);
  52 #endif
  53         return ret;
  54 }
  55
  56 int reiserfs_readdir_dentry(struct dentry *dentry, void *dirent,
  57                            filldir_t filldir, loff_t *pos)
  58 {
  59         struct inode *inode = dentry->d_inode;
  60         struct cpu_key pos_key; /* key of current position in the directory (key of directory entry) */
  61         INITIALIZE_PATH(path_to_entry);
  62         struct buffer_head *bh;
  63         int item_num, entry_num;
  64         const struct reiserfs_key *rkey;
  65         struct item_head *ih, tmp_ih;
  66         int search_res;
  67         char *local_buf;
  68         loff_t next_pos;
  69         char small_buf[32];     /* avoid kmalloc if we can */
  70         struct reiserfs_dir_entry de;
  71         int ret = 0;
  72
  73         reiserfs_write_lock(inode->i_sb);
  74
  75         reiserfs_check_lock_depth(inode->i_sb, "readdir");
  76
  77         /* form key for search the next directory entry using f_pos field of
  78            file structure */
  79         make_cpu_key(&pos_key, inode, *pos ?: DOT_OFFSET, TYPE_DIRENTRY, 3);
  80         next_pos = cpu_key_k_offset(&pos_key);
  81
  82         path_to_entry.reada = PATH_READA;
  83         while (1) {
  84               research:
  85                 /* search the directory item, containing entry with specified key */
  86                 search_res =
  87                     search_by_entry_key(inode->i_sb, &pos_key, &path_to_entry,
  88                                         &de);
  89                 if (search_res == IO_ERROR) {
  90                         // FIXME: we could just skip part of directory which could
  91                         // not be read
  92                         ret = -EIO;
  93                         goto out;
  94                 }
  95                 entry_num = de.de_entry_num;
  96                 bh = de.de_bh;
  97                 item_num = de.de_item_num;
  98                 ih = de.de_ih;
  99                 store_ih(&tmp_ih, ih);
 100
 101                 /* we must have found item, that is item of this directory, */
 102                 RFALSE(COMP_SHORT_KEYS(&(ih->ih_key), &pos_key),
 103                        "vs-9000: found item %h does not match to dir we readdir %K",
 104                        ih, &pos_key);
 105                 RFALSE(item_num > B_NR_ITEMS(bh) - 1,
 106                        "vs-9005 item_num == %d, item amount == %d",
 107                        item_num, B_NR_ITEMS(bh));
 108
 109                 /* and entry must be not more than number of entries in the item */
 110                 RFALSE(I_ENTRY_COUNT(ih) < entry_num,
 111                        "vs-9010: entry number is too big %d (%d)",
 112                        entry_num, I_ENTRY_COUNT(ih));
 113
 114                 if (search_res == POSITION_FOUND
 115                     || entry_num < I_ENTRY_COUNT(ih)) {
 116                         /* go through all entries in the directory item beginning from the entry, that has been found */
 117                         struct reiserfs_de_head *deh =
 118                             B_I_DEH(bh, ih) + entry_num;
 119
 120                         for (; entry_num < I_ENTRY_COUNT(ih);
 121                              entry_num++, deh++) {
 122                                 int d_reclen;
 123                                 char *d_name;
 124                                 off_t d_off;
 125                                 ino_t d_ino;
 126
 127                                 if (!de_visible(deh))
 128                                         /* it is hidden entry */
 129                                         continue;
 130                                 d_reclen = entry_length(bh, ih, entry_num);
 131                                 d_name = B_I_DEH_ENTRY_FILE_NAME(bh, ih, deh);
 132
 133                                 if (d_reclen <= 0 ||
 134                                     d_name + d_reclen > bh->b_data + bh->b_size) {
 135                                         /* There is corrupted data in entry,
 136                                          * We'd better stop here */
 137                                         pathrelse(&path_to_entry);
 138                                         ret = -EIO;
 139                                         goto out;
 140                                 }
 141
 142                                 if (!d_name[d_reclen - 1])
 143                                         d_reclen = strlen(d_name);
 144
 145                                 if (d_reclen >
 146                                     REISERFS_MAX_NAME(inode->i_sb->
 147                                                       s_blocksize)) {
 148                                         /* too big to send back to VFS */
 149                                         continue;
 150                                 }
 151
 152                                 /* Ignore the .reiserfs_priv entry */
 153                                 if (is_privroot_deh(dentry, deh))
 154                                         continue;
 155
 156                                 d_off = deh_offset(deh);
 157                                 *pos = d_off;
 158                                 d_ino = deh_objectid(deh);
 159                                 if (d_reclen <= 32) {
 160                                         local_buf = small_buf;
 161                                 } else {
 162                                         local_buf = kmalloc(d_reclen,
 163                                                             GFP_NOFS);
 164                                         if (!local_buf) {
 165                                                 pathrelse(&path_to_entry);
 166                                                 ret = -ENOMEM;
 167                                                 goto out;
 168                                         }
 169                                         if (item_moved(&tmp_ih, &path_to_entry)) {
 170                                                 kfree(local_buf);
 171                                                 goto research;
 172                                         }
 173                                 }
 174                                 // Note, that we copy name to user space via temporary
 175                                 // buffer (local_buf) because filldir will block if
 176                                 // user space buffer is swapped out. At that time
 177                                 // entry can move to somewhere else
 178                                 memcpy(local_buf, d_name, d_reclen);
 179                                 if (filldir
 180                                     (dirent, local_buf, d_reclen, d_off, d_ino,
 181                                      DT_UNKNOWN) < 0) {
 182                                         if (local_buf != small_buf) {
 183                                                 kfree(local_buf);
 184                                         }
 185                                         goto end;
 186                                 }
 187                                 if (local_buf != small_buf) {
 188                                         kfree(local_buf);
 189                                 }
 190                                 // next entry should be looked for with such offset
 191                                 next_pos = deh_offset(deh) + 1;
 192
 193                                 if (item_moved(&tmp_ih, &path_to_entry)) {
 194                                         goto research;
 195                                 }
 196                         }       /* for */
 197                 }
 198
 199                 if (item_num != B_NR_ITEMS(bh) - 1)
 200                         // end of directory has been reached
 201                         goto end;
 202
 203                 /* item we went through is last item of node. Using right
 204                    delimiting key check is it directory end */
 205                 rkey = get_rkey(&path_to_entry, inode->i_sb);
 206                 if (!comp_le_keys(rkey, &MIN_KEY)) {
 207                         /* set pos_key to key, that is the smallest and greater
 208                            that key of the last entry in the item */
 209                         set_cpu_key_k_offset(&pos_key, next_pos);
 210                         continue;
 211                 }
 212
 213                 if (COMP_SHORT_KEYS(rkey, &pos_key)) {
 214                         // end of directory has been reached
 215                         goto end;
 216                 }
 217
 218                 /* directory continues in the right neighboring block */
 219                 set_cpu_key_k_offset(&pos_key,
 220                                      le_key_k_offset(KEY_FORMAT_3_5, rkey));
 221
 222         }                       /* while */
 223
 224 end:
 225         *pos = next_pos;
 226         pathrelse(&path_to_entry);
 227         reiserfs_check_path(&path_to_entry);
 228 out:
 229         reiserfs_write_unlock(inode->i_sb);
 230         return ret;
 231 }
 232
 233 static int reiserfs_readdir(struct file *file, void *dirent, filldir_t filldir)
 234 {
 235         struct dentry *dentry = file->f_path.dentry;
 236         return reiserfs_readdir_dentry(dentry, dirent, filldir, &file->f_pos);
 237 }
 238
 239 /* compose directory item containing "." and ".." entries (entries are
 240    not aligned to 4 byte boundary) */
 241 /* the last four params are LE */
 242 void make_empty_dir_item_v1(char *body, __le32 dirid, __le32 objid,
 243                             __le32 par_dirid, __le32 par_objid)
 244 {
 245         struct reiserfs_de_head *deh;
 246
 247         memset(body, 0, EMPTY_DIR_SIZE_V1);
 248         deh = (struct reiserfs_de_head *)body;
 249
 250         /* direntry header of "." */
 251         put_deh_offset(&(deh[0]), DOT_OFFSET);
 252         /* these two are from make_le_item_head, and are are LE */
 253         deh[0].deh_dir_id = dirid;
 254         deh[0].deh_objectid = objid;
 255         deh[0].deh_state = 0;   /* Endian safe if 0 */
 256         put_deh_location(&(deh[0]), EMPTY_DIR_SIZE_V1 - strlen("."));
 257         mark_de_visible(&(deh[0]));
 258
 259         /* direntry header of ".." */
 260         put_deh_offset(&(deh[1]), DOT_DOT_OFFSET);
 261         /* key of ".." for the root directory */
 262         /* these two are from the inode, and are are LE */
 263         deh[1].deh_dir_id = par_dirid;
 264         deh[1].deh_objectid = par_objid;
 265         deh[1].deh_state = 0;   /* Endian safe if 0 */
 266         put_deh_location(&(deh[1]), deh_location(&(deh[0])) - strlen(".."));
 267         mark_de_visible(&(deh[1]));
 268
 269         /* copy ".." and "." */
 270         memcpy(body + deh_location(&(deh[0])), ".", 1);
 271         memcpy(body + deh_location(&(deh[1])), "..", 2);
 272 }
 273
 274 /* compose directory item containing "." and ".." entries */
 275 void make_empty_dir_item(char *body, __le32 dirid, __le32 objid,
 276                          __le32 par_dirid, __le32 par_objid)
 277 {
 278         struct reiserfs_de_head *deh;
 279
 280         memset(body, 0, EMPTY_DIR_SIZE);
 281         deh = (struct reiserfs_de_head *)body;
 282
 283         /* direntry header of "." */
 284         put_deh_offset(&(deh[0]), DOT_OFFSET);
 285         /* these two are from make_le_item_head, and are are LE */
 286         deh[0].deh_dir_id = dirid;
 287         deh[0].deh_objectid = objid;
 288         deh[0].deh_state = 0;   /* Endian safe if 0 */
 289         put_deh_location(&(deh[0]), EMPTY_DIR_SIZE - ROUND_UP(strlen(".")));
 290         mark_de_visible(&(deh[0]));
 291
 292         /* direntry header of ".." */
 293         put_deh_offset(&(deh[1]), DOT_DOT_OFFSET);
 294         /* key of ".." for the root directory */
 295         /* these two are from the inode, and are are LE */
 296         deh[1].deh_dir_id = par_dirid;
 297         deh[1].deh_objectid = par_objid;
 298         deh[1].deh_state = 0;   /* Endian safe if 0 */
 299         put_deh_location(&(deh[1]),
 300                          deh_location(&(deh[0])) - ROUND_UP(strlen("..")));
 301         mark_de_visible(&(deh[1]));
 302
 303         /* copy ".." and "." */
 304         memcpy(body + deh_location(&(deh[0])), ".", 1);
 305         memcpy(body + deh_location(&(deh[1])), "..", 2);
 306 }