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                                 if (!d_name[d_reclen - 1])
 125                                         d_reclen = strlen(d_name);
 126
 127                                 if (d_reclen >
 128                                     REISERFS_MAX_NAME(inode->i_sb->
 129                                                       s_blocksize)) {
 130                                         /* too big to send back to VFS */
 131                                         continue;
 132                                 }
 133
 134                                 /* Ignore the .reiserfs_priv entry */
 135                                 if (reiserfs_xattrs(inode->i_sb) &&
 136                                     !old_format_only(inode->i_sb) &&
 137                                     filp->f_path.dentry == inode->i_sb->s_root &&
 138                                     REISERFS_SB(inode->i_sb)->priv_root &&
 139                                     REISERFS_SB(inode->i_sb)->priv_root->d_inode
 140                                     && deh_objectid(deh) ==
 141                                     le32_to_cpu(INODE_PKEY
 142                                                 (REISERFS_SB(inode->i_sb)->
 143                                                  priv_root->d_inode)->
 144                                                 k_objectid)) {
 145                                         continue;
 146                                 }
 147
 148                                 d_off = deh_offset(deh);
 149                                 filp->f_pos = d_off;
 150                                 d_ino = deh_objectid(deh);
 151                                 if (d_reclen <= 32) {
 152                                         local_buf = small_buf;
 153                                 } else {
 154                                         local_buf = kmalloc(d_reclen,
 155                                                             GFP_NOFS);
 156                                         if (!local_buf) {
 157                                                 pathrelse(&path_to_entry);
 158                                                 ret = -ENOMEM;
 159                                                 goto out;
 160                                         }
 161                                         if (item_moved(&tmp_ih, &path_to_entry)) {
 162                                                 kfree(local_buf);
 163                                                 goto research;
 164                                         }
 165                                 }
 166                                 // Note, that we copy name to user space via temporary
 167                                 // buffer (local_buf) because filldir will block if
 168                                 // user space buffer is swapped out. At that time
 169                                 // entry can move to somewhere else
 170                                 memcpy(local_buf, d_name, d_reclen);
 171                                 if (filldir
 172                                     (dirent, local_buf, d_reclen, d_off, d_ino,
 173                                      DT_UNKNOWN) < 0) {
 174                                         if (local_buf != small_buf) {
 175                                                 kfree(local_buf);
 176                                         }
 177                                         goto end;
 178                                 }
 179                                 if (local_buf != small_buf) {
 180                                         kfree(local_buf);
 181                                 }
 182                                 // next entry should be looked for with such offset
 183                                 next_pos = deh_offset(deh) + 1;
 184
 185                                 if (item_moved(&tmp_ih, &path_to_entry)) {
 186                                         goto research;
 187                                 }
 188                         }       /* for */
 189                 }
 190
 191                 if (item_num != B_NR_ITEMS(bh) - 1)
 192                         // end of directory has been reached
 193                         goto end;
 194
 195                 /* item we went through is last item of node. Using right
 196                    delimiting key check is it directory end */
 197                 rkey = get_rkey(&path_to_entry, inode->i_sb);
 198                 if (!comp_le_keys(rkey, &MIN_KEY)) {
 199                         /* set pos_key to key, that is the smallest and greater
 200                            that key of the last entry in the item */
 201                         set_cpu_key_k_offset(&pos_key, next_pos);
 202                         continue;
 203                 }
 204
 205                 if (COMP_SHORT_KEYS(rkey, &pos_key)) {
 206                         // end of directory has been reached
 207                         goto end;
 208                 }
 209
 210                 /* directory continues in the right neighboring block */
 211                 set_cpu_key_k_offset(&pos_key,
 212                                      le_key_k_offset(KEY_FORMAT_3_5, rkey));
 213
 214         }                       /* while */
 215
 216       end:
 217         filp->f_pos = next_pos;
 218         pathrelse(&path_to_entry);
 219         reiserfs_check_path(&path_to_entry);
 220       out:
 221         reiserfs_write_unlock(inode->i_sb);
 222         return ret;
 223 }
 224
 225 /* compose directory item containing "." and ".." entries (entries are
 226    not aligned to 4 byte boundary) */
 227 /* the last four params are LE */
 228 void make_empty_dir_item_v1(char *body, __le32 dirid, __le32 objid,
 229                             __le32 par_dirid, __le32 par_objid)
 230 {
 231         struct reiserfs_de_head *deh;
 232
 233         memset(body, 0, EMPTY_DIR_SIZE_V1);
 234         deh = (struct reiserfs_de_head *)body;
 235
 236         /* direntry header of "." */
 237         put_deh_offset(&(deh[0]), DOT_OFFSET);
 238         /* these two are from make_le_item_head, and are are LE */
 239         deh[0].deh_dir_id = dirid;
 240         deh[0].deh_objectid = objid;
 241         deh[0].deh_state = 0;   /* Endian safe if 0 */
 242         put_deh_location(&(deh[0]), EMPTY_DIR_SIZE_V1 - strlen("."));
 243         mark_de_visible(&(deh[0]));
 244
 245         /* direntry header of ".." */
 246         put_deh_offset(&(deh[1]), DOT_DOT_OFFSET);
 247         /* key of ".." for the root directory */
 248         /* these two are from the inode, and are are LE */
 249         deh[1].deh_dir_id = par_dirid;
 250         deh[1].deh_objectid = par_objid;
 251         deh[1].deh_state = 0;   /* Endian safe if 0 */
 252         put_deh_location(&(deh[1]), deh_location(&(deh[0])) - strlen(".."));
 253         mark_de_visible(&(deh[1]));
 254
 255         /* copy ".." and "." */
 256         memcpy(body + deh_location(&(deh[0])), ".", 1);
 257         memcpy(body + deh_location(&(deh[1])), "..", 2);
 258 }
 259
 260 /* compose directory item containing "." and ".." entries */
 261 void make_empty_dir_item(char *body, __le32 dirid, __le32 objid,
 262                          __le32 par_dirid, __le32 par_objid)
 263 {
 264         struct reiserfs_de_head *deh;
 265
 266         memset(body, 0, EMPTY_DIR_SIZE);
 267         deh = (struct reiserfs_de_head *)body;
 268
 269         /* direntry header of "." */
 270         put_deh_offset(&(deh[0]), DOT_OFFSET);
 271         /* these two are from make_le_item_head, and are are LE */
 272         deh[0].deh_dir_id = dirid;
 273         deh[0].deh_objectid = objid;
 274         deh[0].deh_state = 0;   /* Endian safe if 0 */
 275         put_deh_location(&(deh[0]), EMPTY_DIR_SIZE - ROUND_UP(strlen(".")));
 276         mark_de_visible(&(deh[0]));
 277
 278         /* direntry header of ".." */
 279         put_deh_offset(&(deh[1]), DOT_DOT_OFFSET);
 280         /* key of ".." for the root directory */
 281         /* these two are from the inode, and are are LE */
 282         deh[1].deh_dir_id = par_dirid;
 283         deh[1].deh_objectid = par_objid;
 284         deh[1].deh_state = 0;   /* Endian safe if 0 */
 285         put_deh_location(&(deh[1]),
 286                          deh_location(&(deh[0])) - ROUND_UP(strlen("..")));
 287         mark_de_visible(&(deh[1]));
 288
 289         /* copy ".." and "." */
 290         memcpy(body + deh_location(&(deh[0])), ".", 1);
 291         memcpy(body + deh_location(&(deh[1])), "..", 2);
 292 }