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         if (reiserfs_expose_privroot(dir->d_sb))
  50                 return 0;
  51         return (dir == dir->d_parent && privroot->d_inode &&
  52                 deh->deh_objectid == INODE_PKEY(privroot->d_inode)->k_objectid);
  53 }
  54
  55 int reiserfs_readdir_dentry(struct dentry *dentry, void *dirent,
  56                            filldir_t filldir, loff_t *pos)
  57 {
  58         struct inode *inode = dentry->d_inode;
  59         struct cpu_key pos_key; /* key of current position in the directory (key of directory entry) */
  60         INITIALIZE_PATH(path_to_entry);
  61         struct buffer_head *bh;
  62         int item_num, entry_num;
  63         const struct reiserfs_key *rkey;
  64         struct item_head *ih, tmp_ih;
  65         int search_res;
  66         char *local_buf;
  67         loff_t next_pos;
  68         char small_buf[32];     /* avoid kmalloc if we can */
  69         struct reiserfs_dir_entry de;
  70         int ret = 0;
  71
  72         reiserfs_write_lock(inode->i_sb);
  73
  74         reiserfs_check_lock_depth(inode->i_sb, "readdir");
  75
  76         /* form key for search the next directory entry using f_pos field of
  77            file structure */
  78         make_cpu_key(&pos_key, inode, *pos ?: DOT_OFFSET, TYPE_DIRENTRY, 3);
  79         next_pos = cpu_key_k_offset(&pos_key);
  80
  81         path_to_entry.reada = PATH_READA;
  82         while (1) {
  83               research:
  84                 /* search the directory item, containing entry with specified key */
  85                 search_res =
  86                     search_by_entry_key(inode->i_sb, &pos_key, &path_to_entry,
  87                                         &de);
  88                 if (search_res == IO_ERROR) {
  89                         // FIXME: we could just skip part of directory which could
  90                         // not be read
  91                         ret = -EIO;
  92                         goto out;
  93                 }
  94                 entry_num = de.de_entry_num;
  95                 bh = de.de_bh;
  96                 item_num = de.de_item_num;
  97                 ih = de.de_ih;
  98                 store_ih(&tmp_ih, ih);
  99
 100                 /* we must have found item, that is item of this directory, */
 101                 RFALSE(COMP_SHORT_KEYS(&(ih->ih_key), &pos_key),
 102                        "vs-9000: found item %h does not match to dir we readdir %K",
 103                        ih, &pos_key);
 104                 RFALSE(item_num > B_NR_ITEMS(bh) - 1,
 105                        "vs-9005 item_num == %d, item amount == %d",
 106                        item_num, B_NR_ITEMS(bh));
 107
 108                 /* and entry must be not more than number of entries in the item */
 109                 RFALSE(I_ENTRY_COUNT(ih) < entry_num,
 110                        "vs-9010: entry number is too big %d (%d)",
 111                        entry_num, I_ENTRY_COUNT(ih));
 112
 113                 if (search_res == POSITION_FOUND
 114                     || entry_num < I_ENTRY_COUNT(ih)) {
 115                         /* go through all entries in the directory item beginning from the entry, that has been found */
 116                         struct reiserfs_de_head *deh =
 117                             B_I_DEH(bh, ih) + entry_num;
 118
 119                         for (; entry_num < I_ENTRY_COUNT(ih);
 120                              entry_num++, deh++) {
 121                                 int d_reclen;
 122                                 char *d_name;
 123                                 off_t d_off;
 124                                 ino_t d_ino;
 125
 126                                 if (!de_visible(deh))
 127                                         /* it is hidden entry */
 128                                         continue;
 129                                 d_reclen = entry_length(bh, ih, entry_num);
 130                                 d_name = B_I_DEH_ENTRY_FILE_NAME(bh, ih, deh);
 131
 132                                 if (d_reclen <= 0 ||
 133                                     d_name + d_reclen > bh->b_data + bh->b_size) {
 134                                         /* There is corrupted data in entry,
 135                                          * We'd better stop here */
 136                                         pathrelse(&path_to_entry);
 137                                         ret = -EIO;
 138                                         goto out;
 139                                 }
 140
 141                                 if (!d_name[d_reclen - 1])
 142                                         d_reclen = strlen(d_name);
 143
 144                                 if (d_reclen >
 145                                     REISERFS_MAX_NAME(inode->i_sb->
 146                                                       s_blocksize)) {
 147                                         /* too big to send back to VFS */
 148                                         continue;
 149                                 }
 150
 151                                 /* Ignore the .reiserfs_priv entry */
 152                                 if (is_privroot_deh(dentry, deh))
 153                                         continue;
 154
 155                                 d_off = deh_offset(deh);
 156                                 *pos = d_off;
 157                                 d_ino = deh_objectid(deh);
 158                                 if (d_reclen <= 32) {
 159                                         local_buf = small_buf;
 160                                 } else {
 161                                         local_buf = kmalloc(d_reclen,
 162                                                             GFP_NOFS);
 163                                         if (!local_buf) {
 164                                                 pathrelse(&path_to_entry);
 165                                                 ret = -ENOMEM;
 166                                                 goto out;
 167                                         }
 168                                         if (item_moved(&tmp_ih, &path_to_entry)) {
 169                                                 kfree(local_buf);
 170                                                 goto research;
 171                                         }
 172                                 }
 173                                 // Note, that we copy name to user space via temporary
 174                                 // buffer (local_buf) because filldir will block if
 175                                 // user space buffer is swapped out. At that time
 176                                 // entry can move to somewhere else
 177                                 memcpy(local_buf, d_name, d_reclen);
 178
 179                                 /*
 180                                  * Since filldir might sleep, we can release
 181                                  * the write lock here for other waiters
 182                                  */
 183                                 reiserfs_write_unlock(inode->i_sb);
 184                                 if (filldir
 185                                     (dirent, local_buf, d_reclen, d_off, d_ino,
 186                                      DT_UNKNOWN) < 0) {
 187                                         reiserfs_write_lock(inode->i_sb);
 188                                         if (local_buf != small_buf) {
 189                                                 kfree(local_buf);
 190                                         }
 191                                         goto end;
 192                                 }
 193                                 reiserfs_write_lock(inode->i_sb);
 194                                 if (local_buf != small_buf) {
 195                                         kfree(local_buf);
 196                                 }
 197                                 // next entry should be looked for with such offset
 198                                 next_pos = deh_offset(deh) + 1;
 199
 200                                 if (item_moved(&tmp_ih, &path_to_entry)) {
 201                                         goto research;
 202                                 }
 203                         }       /* for */
 204                 }
 205
 206                 if (item_num != B_NR_ITEMS(bh) - 1)
 207                         // end of directory has been reached
 208                         goto end;
 209
 210                 /* item we went through is last item of node. Using right
 211                    delimiting key check is it directory end */
 212                 rkey = get_rkey(&path_to_entry, inode->i_sb);
 213                 if (!comp_le_keys(rkey, &MIN_KEY)) {
 214                         /* set pos_key to key, that is the smallest and greater
 215                            that key of the last entry in the item */
 216                         set_cpu_key_k_offset(&pos_key, next_pos);
 217                         continue;
 218                 }
 219
 220                 if (COMP_SHORT_KEYS(rkey, &pos_key)) {
 221                         // end of directory has been reached
 222                         goto end;
 223                 }
 224
 225                 /* directory continues in the right neighboring block */
 226                 set_cpu_key_k_offset(&pos_key,
 227                                      le_key_k_offset(KEY_FORMAT_3_5, rkey));
 228
 229         }                       /* while */
 230
 231 end:
 232         *pos = next_pos;
 233         pathrelse(&path_to_entry);
 234         reiserfs_check_path(&path_to_entry);
 235 out:
 236         reiserfs_write_unlock(inode->i_sb);
 237         return ret;
 238 }
 239
 240 static int reiserfs_readdir(struct file *file, void *dirent, filldir_t filldir)
 241 {
 242         struct dentry *dentry = file->f_path.dentry;
 243         return reiserfs_readdir_dentry(dentry, dirent, filldir, &file->f_pos);
 244 }
 245
 246 /* compose directory item containing "." and ".." entries (entries are
 247    not aligned to 4 byte boundary) */
 248 /* the last four params are LE */
 249 void make_empty_dir_item_v1(char *body, __le32 dirid, __le32 objid,
 250                             __le32 par_dirid, __le32 par_objid)
 251 {
 252         struct reiserfs_de_head *deh;
 253
 254         memset(body, 0, EMPTY_DIR_SIZE_V1);
 255         deh = (struct reiserfs_de_head *)body;
 256
 257         /* direntry header of "." */
 258         put_deh_offset(&(deh[0]), DOT_OFFSET);
 259         /* these two are from make_le_item_head, and are are LE */
 260         deh[0].deh_dir_id = dirid;
 261         deh[0].deh_objectid = objid;
 262         deh[0].deh_state = 0;   /* Endian safe if 0 */
 263         put_deh_location(&(deh[0]), EMPTY_DIR_SIZE_V1 - strlen("."));
 264         mark_de_visible(&(deh[0]));
 265
 266         /* direntry header of ".." */
 267         put_deh_offset(&(deh[1]), DOT_DOT_OFFSET);
 268         /* key of ".." for the root directory */
 269         /* these two are from the inode, and are are LE */
 270         deh[1].deh_dir_id = par_dirid;
 271         deh[1].deh_objectid = par_objid;
 272         deh[1].deh_state = 0;   /* Endian safe if 0 */
 273         put_deh_location(&(deh[1]), deh_location(&(deh[0])) - strlen(".."));
 274         mark_de_visible(&(deh[1]));
 275
 276         /* copy ".." and "." */
 277         memcpy(body + deh_location(&(deh[0])), ".", 1);
 278         memcpy(body + deh_location(&(deh[1])), "..", 2);
 279 }
 280
 281 /* compose directory item containing "." and ".." entries */
 282 void make_empty_dir_item(char *body, __le32 dirid, __le32 objid,
 283                          __le32 par_dirid, __le32 par_objid)
 284 {
 285         struct reiserfs_de_head *deh;
 286
 287         memset(body, 0, EMPTY_DIR_SIZE);
 288         deh = (struct reiserfs_de_head *)body;
 289
 290         /* direntry header of "." */
 291         put_deh_offset(&(deh[0]), DOT_OFFSET);
 292         /* these two are from make_le_item_head, and are are LE */
 293         deh[0].deh_dir_id = dirid;
 294         deh[0].deh_objectid = objid;
 295         deh[0].deh_state = 0;   /* Endian safe if 0 */
 296         put_deh_location(&(deh[0]), EMPTY_DIR_SIZE - ROUND_UP(strlen(".")));
 297         mark_de_visible(&(deh[0]));
 298
 299         /* direntry header of ".." */
 300         put_deh_offset(&(deh[1]), DOT_DOT_OFFSET);
 301         /* key of ".." for the root directory */
 302         /* these two are from the inode, and are are LE */
 303         deh[1].deh_dir_id = par_dirid;
 304         deh[1].deh_objectid = par_objid;
 305         deh[1].deh_state = 0;   /* Endian safe if 0 */
 306         put_deh_location(&(deh[1]),
 307                          deh_location(&(deh[0])) - ROUND_UP(strlen("..")));
 308         mark_de_visible(&(deh[1]));
 309
 310         /* copy ".." and "." */
 311         memcpy(body + deh_location(&(deh[0])), ".", 1);
 312         memcpy(body + deh_location(&(deh[1])), "..", 2);
 313 }