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         struct dentry *privroot = REISERFS_SB(dir->d_sb)->priv_root;
  48         if (reiserfs_expose_privroot(dir->d_sb))
  49                 return 0;
  50         return (dir == dir->d_parent && privroot->d_inode &&
  51                 deh->deh_objectid == INODE_PKEY(privroot->d_inode)->k_objectid);
  52 }
  53
  54 int reiserfs_readdir_dentry(struct dentry *dentry, void *dirent,
  55                            filldir_t filldir, loff_t *pos)
  56 {
  57         struct inode *inode = dentry->d_inode;
  58         struct cpu_key pos_key; /* key of current position in the directory (key of directory entry) */
  59         INITIALIZE_PATH(path_to_entry);
  60         struct buffer_head *bh;
  61         int item_num, entry_num;
  62         const struct reiserfs_key *rkey;
  63         struct item_head *ih, tmp_ih;
  64         int search_res;
  65         char *local_buf;
  66         loff_t next_pos;
  67         char small_buf[32];     /* avoid kmalloc if we can */
  68         struct reiserfs_dir_entry de;
  69         int ret = 0;
  70
  71         reiserfs_write_lock(inode->i_sb);
  72
  73         reiserfs_check_lock_depth(inode->i_sb, "readdir");
  74
  75         /* form key for search the next directory entry using f_pos field of
  76            file structure */
  77         make_cpu_key(&pos_key, inode, *pos ?: DOT_OFFSET, TYPE_DIRENTRY, 3);
  78         next_pos = cpu_key_k_offset(&pos_key);
  79
  80         path_to_entry.reada = PATH_READA;
  81         while (1) {
  82               research:
  83                 /* search the directory item, containing entry with specified key */
  84                 search_res =
  85                     search_by_entry_key(inode->i_sb, &pos_key, &path_to_entry,
  86                                         &de);
  87                 if (search_res == IO_ERROR) {
  88                         // FIXME: we could just skip part of directory which could
  89                         // not be read
  90                         ret = -EIO;
  91                         goto out;
  92                 }
  93                 entry_num = de.de_entry_num;
  94                 bh = de.de_bh;
  95                 item_num = de.de_item_num;
  96                 ih = de.de_ih;
  97                 store_ih(&tmp_ih, ih);
  98
  99                 /* we must have found item, that is item of this directory, */
 100                 RFALSE(COMP_SHORT_KEYS(&(ih->ih_key), &pos_key),
 101                        "vs-9000: found item %h does not match to dir we readdir %K",
 102                        ih, &pos_key);
 103                 RFALSE(item_num > B_NR_ITEMS(bh) - 1,
 104                        "vs-9005 item_num == %d, item amount == %d",
 105                        item_num, B_NR_ITEMS(bh));
 106
 107                 /* and entry must be not more than number of entries in the item */
 108                 RFALSE(I_ENTRY_COUNT(ih) < entry_num,
 109                        "vs-9010: entry number is too big %d (%d)",
 110                        entry_num, I_ENTRY_COUNT(ih));
 111
 112                 if (search_res == POSITION_FOUND
 113                     || entry_num < I_ENTRY_COUNT(ih)) {
 114                         /* go through all entries in the directory item beginning from the entry, that has been found */
 115                         struct reiserfs_de_head *deh =
 116                             B_I_DEH(bh, ih) + entry_num;
 117
 118                         for (; entry_num < I_ENTRY_COUNT(ih);
 119                              entry_num++, deh++) {
 120                                 int d_reclen;
 121                                 char *d_name;
 122                                 off_t d_off;
 123                                 ino_t d_ino;
 124
 125                                 if (!de_visible(deh))
 126                                         /* it is hidden entry */
 127                                         continue;
 128                                 d_reclen = entry_length(bh, ih, entry_num);
 129                                 d_name = B_I_DEH_ENTRY_FILE_NAME(bh, ih, deh);
 130
 131                                 if (d_reclen <= 0 ||
 132                                     d_name + d_reclen > bh->b_data + bh->b_size) {
 133                                         /* There is corrupted data in entry,
 134                                          * We'd better stop here */
 135                                         pathrelse(&path_to_entry);
 136                                         ret = -EIO;
 137                                         goto out;
 138                                 }
 139
 140                                 if (!d_name[d_reclen - 1])
 141                                         d_reclen = strlen(d_name);
 142
 143                                 if (d_reclen >
 144                                     REISERFS_MAX_NAME(inode->i_sb->
 145                                                       s_blocksize)) {
 146                                         /* too big to send back to VFS */
 147                                         continue;
 148                                 }
 149
 150                                 /* Ignore the .reiserfs_priv entry */
 151                                 if (is_privroot_deh(dentry, deh))
 152                                         continue;
 153
 154                                 d_off = deh_offset(deh);
 155                                 *pos = d_off;
 156                                 d_ino = deh_objectid(deh);
 157                                 if (d_reclen <= 32) {
 158                                         local_buf = small_buf;
 159                                 } else {
 160                                         local_buf = kmalloc(d_reclen,
 161                                                             GFP_NOFS);
 162                                         if (!local_buf) {
 163                                                 pathrelse(&path_to_entry);
 164                                                 ret = -ENOMEM;
 165                                                 goto out;
 166                                         }
 167                                         if (item_moved(&tmp_ih, &path_to_entry)) {
 168                                                 kfree(local_buf);
 169                                                 goto research;
 170                                         }
 171                                 }
 172                                 // Note, that we copy name to user space via temporary
 173                                 // buffer (local_buf) because filldir will block if
 174                                 // user space buffer is swapped out. At that time
 175                                 // entry can move to somewhere else
 176                                 memcpy(local_buf, d_name, d_reclen);
 177
 178                                 /*
 179                                  * Since filldir might sleep, we can release
 180                                  * the write lock here for other waiters
 181                                  */
 182                                 reiserfs_write_unlock(inode->i_sb);
 183                                 if (filldir
 184                                     (dirent, local_buf, d_reclen, d_off, d_ino,
 185                                      DT_UNKNOWN) < 0) {
 186                                         reiserfs_write_lock(inode->i_sb);
 187                                         if (local_buf != small_buf) {
 188                                                 kfree(local_buf);
 189                                         }
 190                                         goto end;
 191                                 }
 192                                 reiserfs_write_lock(inode->i_sb);
 193                                 if (local_buf != small_buf) {
 194                                         kfree(local_buf);
 195                                 }
 196                                 // next entry should be looked for with such offset
 197                                 next_pos = deh_offset(deh) + 1;
 198
 199                                 if (item_moved(&tmp_ih, &path_to_entry)) {
 200                                         goto research;
 201                                 }
 202                         }       /* for */
 203                 }
 204
 205                 if (item_num != B_NR_ITEMS(bh) - 1)
 206                         // end of directory has been reached
 207                         goto end;
 208
 209                 /* item we went through is last item of node. Using right
 210                    delimiting key check is it directory end */
 211                 rkey = get_rkey(&path_to_entry, inode->i_sb);
 212                 if (!comp_le_keys(rkey, &MIN_KEY)) {
 213                         /* set pos_key to key, that is the smallest and greater
 214                            that key of the last entry in the item */
 215                         set_cpu_key_k_offset(&pos_key, next_pos);
 216                         continue;
 217                 }
 218
 219                 if (COMP_SHORT_KEYS(rkey, &pos_key)) {
 220                         // end of directory has been reached
 221                         goto end;
 222                 }
 223
 224                 /* directory continues in the right neighboring block */
 225                 set_cpu_key_k_offset(&pos_key,
 226                                      le_key_k_offset(KEY_FORMAT_3_5, rkey));
 227
 228         }                       /* while */
 229
 230 end:
 231         *pos = next_pos;
 232         pathrelse(&path_to_entry);
 233         reiserfs_check_path(&path_to_entry);
 234 out:
 235         reiserfs_write_unlock(inode->i_sb);
 236         return ret;
 237 }
 238
 239 static int reiserfs_readdir(struct file *file, void *dirent, filldir_t filldir)
 240 {
 241         struct dentry *dentry = file->f_path.dentry;
 242         return reiserfs_readdir_dentry(dentry, dirent, filldir, &file->f_pos);
 243 }
 244
 245 /* compose directory item containing "." and ".." entries (entries are
 246    not aligned to 4 byte boundary) */
 247 /* the last four params are LE */
 248 void make_empty_dir_item_v1(char *body, __le32 dirid, __le32 objid,
 249                             __le32 par_dirid, __le32 par_objid)
 250 {
 251         struct reiserfs_de_head *deh;
 252
 253         memset(body, 0, EMPTY_DIR_SIZE_V1);
 254         deh = (struct reiserfs_de_head *)body;
 255
 256         /* direntry header of "." */
 257         put_deh_offset(&(deh[0]), DOT_OFFSET);
 258         /* these two are from make_le_item_head, and are are LE */
 259         deh[0].deh_dir_id = dirid;
 260         deh[0].deh_objectid = objid;
 261         deh[0].deh_state = 0;   /* Endian safe if 0 */
 262         put_deh_location(&(deh[0]), EMPTY_DIR_SIZE_V1 - strlen("."));
 263         mark_de_visible(&(deh[0]));
 264
 265         /* direntry header of ".." */
 266         put_deh_offset(&(deh[1]), DOT_DOT_OFFSET);
 267         /* key of ".." for the root directory */
 268         /* these two are from the inode, and are are LE */
 269         deh[1].deh_dir_id = par_dirid;
 270         deh[1].deh_objectid = par_objid;
 271         deh[1].deh_state = 0;   /* Endian safe if 0 */
 272         put_deh_location(&(deh[1]), deh_location(&(deh[0])) - strlen(".."));
 273         mark_de_visible(&(deh[1]));
 274
 275         /* copy ".." and "." */
 276         memcpy(body + deh_location(&(deh[0])), ".", 1);
 277         memcpy(body + deh_location(&(deh[1])), "..", 2);
 278 }
 279
 280 /* compose directory item containing "." and ".." entries */
 281 void make_empty_dir_item(char *body, __le32 dirid, __le32 objid,
 282                          __le32 par_dirid, __le32 par_objid)
 283 {
 284         struct reiserfs_de_head *deh;
 285
 286         memset(body, 0, EMPTY_DIR_SIZE);
 287         deh = (struct reiserfs_de_head *)body;
 288
 289         /* direntry header of "." */
 290         put_deh_offset(&(deh[0]), DOT_OFFSET);
 291         /* these two are from make_le_item_head, and are are LE */
 292         deh[0].deh_dir_id = dirid;
 293         deh[0].deh_objectid = objid;
 294         deh[0].deh_state = 0;   /* Endian safe if 0 */
 295         put_deh_location(&(deh[0]), EMPTY_DIR_SIZE - ROUND_UP(strlen(".")));
 296         mark_de_visible(&(deh[0]));
 297
 298         /* direntry header of ".." */
 299         put_deh_offset(&(deh[1]), DOT_DOT_OFFSET);
 300         /* key of ".." for the root directory */
 301         /* these two are from the inode, and are are LE */
 302         deh[1].deh_dir_id = par_dirid;
 303         deh[1].deh_objectid = par_objid;
 304         deh[1].deh_state = 0;   /* Endian safe if 0 */
 305         put_deh_location(&(deh[1]),
 306                          deh_location(&(deh[0])) - ROUND_UP(strlen("..")));
 307         mark_de_visible(&(deh[1]));
 308
 309         /* copy ".." and "." */
 310         memcpy(body + deh_location(&(deh[0])), ".", 1);
 311         memcpy(body + deh_location(&(deh[1])), "..", 2);
 312 }