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 //
  45 static int reiserfs_readdir(struct file *filp, void *dirent, filldir_t filldir)
  46 {
  47         struct inode *inode = filp->f_path.dentry->d_inode;
  48         struct cpu_key pos_key; /* key of current position in the directory (key of directory entry) */
  49         INITIALIZE_PATH(path_to_entry);
  50         struct buffer_head *bh;
  51         int item_num, entry_num;
  52         const struct reiserfs_key *rkey;
  53         struct item_head *ih, tmp_ih;
  54         int search_res;
  55         char *local_buf;
  56         loff_t next_pos;
  57         char small_buf[32];     /* avoid kmalloc if we can */
  58         struct reiserfs_dir_entry de;
  59         int ret = 0;
  60
  61         reiserfs_write_lock(inode->i_sb);
  62
  63         reiserfs_check_lock_depth(inode->i_sb, "readdir");
  64
  65         /* form key for search the next directory entry using f_pos field of
  66            file structure */
  67         make_cpu_key(&pos_key, inode,
  68                      (filp->f_pos) ? (filp->f_pos) : DOT_OFFSET, TYPE_DIRENTRY,
  69                      3);
  70         next_pos = cpu_key_k_offset(&pos_key);
  71
  72         /*  reiserfs_warning (inode->i_sb, "reiserfs_readdir 1: f_pos = %Ld", filp->f_pos); */
  73
  74         path_to_entry.reada = PATH_READA;
  75         while (1) {
  76               research:
  77                 /* search the directory item, containing entry with specified key */
  78                 search_res =
  79                     search_by_entry_key(inode->i_sb, &pos_key, &path_to_entry,
  80                                         &de);
  81                 if (search_res == IO_ERROR) {
  82                         // FIXME: we could just skip part of directory which could
  83                         // not be read
  84                         ret = -EIO;
  85                         goto out;
  86                 }
  87                 entry_num = de.de_entry_num;
  88                 bh = de.de_bh;
  89                 item_num = de.de_item_num;
  90                 ih = de.de_ih;
  91                 store_ih(&tmp_ih, ih);
  92
  93                 /* we must have found item, that is item of this directory, */
  94                 RFALSE(COMP_SHORT_KEYS(&(ih->ih_key), &pos_key),
  95                        "vs-9000: found item %h does not match to dir we readdir %K",
  96                        ih, &pos_key);
  97                 RFALSE(item_num > B_NR_ITEMS(bh) - 1,
  98                        "vs-9005 item_num == %d, item amount == %d",
  99                        item_num, B_NR_ITEMS(bh));
 100
 101                 /* and entry must be not more than number of entries in the item */
 102                 RFALSE(I_ENTRY_COUNT(ih) < entry_num,
 103                        "vs-9010: entry number is too big %d (%d)",
 104                        entry_num, I_ENTRY_COUNT(ih));
 105
 106                 if (search_res == POSITION_FOUND
 107                     || entry_num < I_ENTRY_COUNT(ih)) {
 108                         /* go through all entries in the directory item beginning from the entry, that has been found */
 109                         struct reiserfs_de_head *deh =
 110                             B_I_DEH(bh, ih) + entry_num;
 111
 112                         for (; entry_num < I_ENTRY_COUNT(ih);
 113                              entry_num++, deh++) {
 114                                 int d_reclen;
 115                                 char *d_name;
 116                                 off_t d_off;
 117                                 ino_t d_ino;
 118
 119                                 if (!de_visible(deh))
 120                                         /* it is hidden entry */
 121                                         continue;
 122                                 d_reclen = entry_length(bh, ih, entry_num);
 123                                 d_name = B_I_DEH_ENTRY_FILE_NAME(bh, ih, deh);
 124
 125                                 if (d_reclen <= 0 ||
 126                                     d_name + d_reclen > bh->b_data + bh->b_size) {
 127                                         /* There is corrupted data in entry,
 128                                          * We'd better stop here */
 129                                         pathrelse(&path_to_entry);
 130                                         ret = -EIO;
 131                                         goto out;
 132                                 }
 133
 134                                 if (!d_name[d_reclen - 1])
 135                                         d_reclen = strlen(d_name);
 136
 137                                 if (d_reclen >
 138                                     REISERFS_MAX_NAME(inode->i_sb->
 139                                                       s_blocksize)) {
 140                                         /* too big to send back to VFS */
 141                                         continue;
 142                                 }
 143
 144                                 /* Ignore the .reiserfs_priv entry */
 145                                 if (reiserfs_xattrs(inode->i_sb) &&
 146                                     !old_format_only(inode->i_sb) &&
 147                                     filp->f_path.dentry == inode->i_sb->s_root &&
 148                                     REISERFS_SB(inode->i_sb)->priv_root &&
 149                                     REISERFS_SB(inode->i_sb)->priv_root->d_inode
 150                                     && deh_objectid(deh) ==
 151                                     le32_to_cpu(INODE_PKEY
 152                                                 (REISERFS_SB(inode->i_sb)->
 153                                                  priv_root->d_inode)->
 154                                                 k_objectid)) {
 155                                         continue;
 156                                 }
 157
 158                                 d_off = deh_offset(deh);
 159                                 filp->f_pos = d_off;
 160                                 d_ino = deh_objectid(deh);
 161                                 if (d_reclen <= 32) {
 162                                         local_buf = small_buf;
 163                                 } else {
 164                                         local_buf = kmalloc(d_reclen,
 165                                                             GFP_NOFS);
 166                                         if (!local_buf) {
 167                                                 pathrelse(&path_to_entry);
 168                                                 ret = -ENOMEM;
 169                                                 goto out;
 170                                         }
 171                                         if (item_moved(&tmp_ih, &path_to_entry)) {
 172                                                 kfree(local_buf);
 173                                                 goto research;
 174                                         }
 175                                 }
 176                                 // Note, that we copy name to user space via temporary
 177                                 // buffer (local_buf) because filldir will block if
 178                                 // user space buffer is swapped out. At that time
 179                                 // entry can move to somewhere else
 180                                 memcpy(local_buf, d_name, d_reclen);
 181                                 if (filldir
 182                                     (dirent, local_buf, d_reclen, d_off, d_ino,
 183                                      DT_UNKNOWN) < 0) {
 184                                         if (local_buf != small_buf) {
 185                                                 kfree(local_buf);
 186                                         }
 187                                         goto end;
 188                                 }
 189                                 if (local_buf != small_buf) {
 190                                         kfree(local_buf);
 191                                 }
 192                                 // next entry should be looked for with such offset
 193                                 next_pos = deh_offset(deh) + 1;
 194
 195                                 if (item_moved(&tmp_ih, &path_to_entry)) {
 196                                         goto research;
 197                                 }
 198                         }       /* for */
 199                 }
 200
 201                 if (item_num != B_NR_ITEMS(bh) - 1)
 202                         // end of directory has been reached
 203                         goto end;
 204
 205                 /* item we went through is last item of node. Using right
 206                    delimiting key check is it directory end */
 207                 rkey = get_rkey(&path_to_entry, inode->i_sb);
 208                 if (!comp_le_keys(rkey, &MIN_KEY)) {
 209                         /* set pos_key to key, that is the smallest and greater
 210                            that key of the last entry in the item */
 211                         set_cpu_key_k_offset(&pos_key, next_pos);
 212                         continue;
 213                 }
 214
 215                 if (COMP_SHORT_KEYS(rkey, &pos_key)) {
 216                         // end of directory has been reached
 217                         goto end;
 218                 }
 219
 220                 /* directory continues in the right neighboring block */
 221                 set_cpu_key_k_offset(&pos_key,
 222                                      le_key_k_offset(KEY_FORMAT_3_5, rkey));
 223
 224         }                       /* while */
 225
 226       end:
 227         filp->f_pos = next_pos;
 228         pathrelse(&path_to_entry);
 229         reiserfs_check_path(&path_to_entry);
 230       out:
 231         reiserfs_write_unlock(inode->i_sb);
 232         return ret;
 233 }
 234
 235 /* compose directory item containing "." and ".." entries (entries are
 236    not aligned to 4 byte boundary) */
 237 /* the last four params are LE */
 238 void make_empty_dir_item_v1(char *body, __le32 dirid, __le32 objid,
 239                             __le32 par_dirid, __le32 par_objid)
 240 {
 241         struct reiserfs_de_head *deh;
 242
 243         memset(body, 0, EMPTY_DIR_SIZE_V1);
 244         deh = (struct reiserfs_de_head *)body;
 245
 246         /* direntry header of "." */
 247         put_deh_offset(&(deh[0]), DOT_OFFSET);
 248         /* these two are from make_le_item_head, and are are LE */
 249         deh[0].deh_dir_id = dirid;
 250         deh[0].deh_objectid = objid;
 251         deh[0].deh_state = 0;   /* Endian safe if 0 */
 252         put_deh_location(&(deh[0]), EMPTY_DIR_SIZE_V1 - strlen("."));
 253         mark_de_visible(&(deh[0]));
 254
 255         /* direntry header of ".." */
 256         put_deh_offset(&(deh[1]), DOT_DOT_OFFSET);
 257         /* key of ".." for the root directory */
 258         /* these two are from the inode, and are are LE */
 259         deh[1].deh_dir_id = par_dirid;
 260         deh[1].deh_objectid = par_objid;
 261         deh[1].deh_state = 0;   /* Endian safe if 0 */
 262         put_deh_location(&(deh[1]), deh_location(&(deh[0])) - strlen(".."));
 263         mark_de_visible(&(deh[1]));
 264
 265         /* copy ".." and "." */
 266         memcpy(body + deh_location(&(deh[0])), ".", 1);
 267         memcpy(body + deh_location(&(deh[1])), "..", 2);
 268 }
 269
 270 /* compose directory item containing "." and ".." entries */
 271 void make_empty_dir_item(char *body, __le32 dirid, __le32 objid,
 272                          __le32 par_dirid, __le32 par_objid)
 273 {
 274         struct reiserfs_de_head *deh;
 275
 276         memset(body, 0, EMPTY_DIR_SIZE);
 277         deh = (struct reiserfs_de_head *)body;
 278
 279         /* direntry header of "." */
 280         put_deh_offset(&(deh[0]), DOT_OFFSET);
 281         /* these two are from make_le_item_head, and are are LE */
 282         deh[0].deh_dir_id = dirid;
 283         deh[0].deh_objectid = objid;
 284         deh[0].deh_state = 0;   /* Endian safe if 0 */
 285         put_deh_location(&(deh[0]), EMPTY_DIR_SIZE - ROUND_UP(strlen(".")));
 286         mark_de_visible(&(deh[0]));
 287
 288         /* direntry header of ".." */
 289         put_deh_offset(&(deh[1]), DOT_DOT_OFFSET);
 290         /* key of ".." for the root directory */
 291         /* these two are from the inode, and are are LE */
 292         deh[1].deh_dir_id = par_dirid;
 293         deh[1].deh_objectid = par_objid;
 294         deh[1].deh_state = 0;   /* Endian safe if 0 */
 295         put_deh_location(&(deh[1]),
 296                          deh_location(&(deh[0])) - ROUND_UP(strlen("..")));
 297         mark_de_visible(&(deh[1]));
 298
 299         /* copy ".." and "." */
 300         memcpy(body + deh_location(&(deh[0])), ".", 1);
 301         memcpy(body + deh_location(&(deh[1])), "..", 2);
 302 }