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/smp_lock.h>
  11 #include <linux/buffer_head.h>
  12 #include <asm/uaccess.h>
  13
  14 extern 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         .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 //
  46 static int reiserfs_readdir(struct file *filp, void *dirent, filldir_t filldir)
  47 {
  48         struct inode *inode = filp->f_path.dentry->d_inode;
  49         struct cpu_key pos_key; /* key of current position in the directory (key of directory entry) */
  50         INITIALIZE_PATH(path_to_entry);
  51         struct buffer_head *bh;
  52         int item_num, entry_num;
  53         const struct reiserfs_key *rkey;
  54         struct item_head *ih, tmp_ih;
  55         int search_res;
  56         char *local_buf;
  57         loff_t next_pos;
  58         char small_buf[32];     /* avoid kmalloc if we can */
  59         struct reiserfs_dir_entry de;
  60         int ret = 0;
  61
  62         reiserfs_write_lock(inode->i_sb);
  63
  64         reiserfs_check_lock_depth(inode->i_sb, "readdir");
  65
  66         /* form key for search the next directory entry using f_pos field of
  67            file structure */
  68         make_cpu_key(&pos_key, inode,
  69                      (filp->f_pos) ? (filp->f_pos) : DOT_OFFSET, TYPE_DIRENTRY,
  70                      3);
  71         next_pos = cpu_key_k_offset(&pos_key);
  72
  73         /*  reiserfs_warning (inode->i_sb, "reiserfs_readdir 1: f_pos = %Ld", filp->f_pos); */
  74
  75         path_to_entry.reada = PATH_READA;
  76         while (1) {
  77               research:
  78                 /* search the directory item, containing entry with specified key */
  79                 search_res =
  80                     search_by_entry_key(inode->i_sb, &pos_key, &path_to_entry,
  81                                         &de);
  82                 if (search_res == IO_ERROR) {
  83                         // FIXME: we could just skip part of directory which could
  84                         // not be read
  85                         ret = -EIO;
  86                         goto out;
  87                 }
  88                 entry_num = de.de_entry_num;
  89                 bh = de.de_bh;
  90                 item_num = de.de_item_num;
  91                 ih = de.de_ih;
  92                 store_ih(&tmp_ih, ih);
  93
  94                 /* we must have found item, that is item of this directory, */
  95                 RFALSE(COMP_SHORT_KEYS(&(ih->ih_key), &pos_key),
  96                        "vs-9000: found item %h does not match to dir we readdir %K",
  97                        ih, &pos_key);
  98                 RFALSE(item_num > B_NR_ITEMS(bh) - 1,
  99                        "vs-9005 item_num == %d, item amount == %d",
 100                        item_num, B_NR_ITEMS(bh));
 101
 102                 /* and entry must be not more than number of entries in the item */
 103                 RFALSE(I_ENTRY_COUNT(ih) < entry_num,
 104                        "vs-9010: entry number is too big %d (%d)",
 105                        entry_num, I_ENTRY_COUNT(ih));
 106
 107                 if (search_res == POSITION_FOUND
 108                     || entry_num < I_ENTRY_COUNT(ih)) {
 109                         /* go through all entries in the directory item beginning from the entry, that has been found */
 110                         struct reiserfs_de_head *deh =
 111                             B_I_DEH(bh, ih) + entry_num;
 112
 113                         for (; entry_num < I_ENTRY_COUNT(ih);
 114                              entry_num++, deh++) {
 115                                 int d_reclen;
 116                                 char *d_name;
 117                                 off_t d_off;
 118                                 ino_t d_ino;
 119
 120                                 if (!de_visible(deh))
 121                                         /* it is hidden entry */
 122                                         continue;
 123                                 d_reclen = entry_length(bh, ih, entry_num);
 124                                 d_name = B_I_DEH_ENTRY_FILE_NAME(bh, ih, deh);
 125                                 if (!d_name[d_reclen - 1])
 126                                         d_reclen = strlen(d_name);
 127
 128                                 if (d_reclen >
 129                                     REISERFS_MAX_NAME(inode->i_sb->
 130                                                       s_blocksize)) {
 131                                         /* too big to send back to VFS */
 132                                         continue;
 133                                 }
 134
 135                                 /* Ignore the .reiserfs_priv entry */
 136                                 if (reiserfs_xattrs(inode->i_sb) &&
 137                                     !old_format_only(inode->i_sb) &&
 138                                     filp->f_path.dentry == inode->i_sb->s_root &&
 139                                     REISERFS_SB(inode->i_sb)->priv_root &&
 140                                     REISERFS_SB(inode->i_sb)->priv_root->d_inode
 141                                     && deh_objectid(deh) ==
 142                                     le32_to_cpu(INODE_PKEY
 143                                                 (REISERFS_SB(inode->i_sb)->
 144                                                  priv_root->d_inode)->
 145                                                 k_objectid)) {
 146                                         continue;
 147                                 }
 148
 149                                 d_off = deh_offset(deh);
 150                                 filp->f_pos = d_off;
 151                                 d_ino = deh_objectid(deh);
 152                                 if (d_reclen <= 32) {
 153                                         local_buf = small_buf;
 154                                 } else {
 155                                         local_buf = kmalloc(d_reclen,
 156                                                             GFP_NOFS);
 157                                         if (!local_buf) {
 158                                                 pathrelse(&path_to_entry);
 159                                                 ret = -ENOMEM;
 160                                                 goto out;
 161                                         }
 162                                         if (item_moved(&tmp_ih, &path_to_entry)) {
 163                                                 kfree(local_buf);
 164                                                 goto research;
 165                                         }
 166                                 }
 167                                 // Note, that we copy name to user space via temporary
 168                                 // buffer (local_buf) because filldir will block if
 169                                 // user space buffer is swapped out. At that time
 170                                 // entry can move to somewhere else
 171                                 memcpy(local_buf, d_name, d_reclen);
 172                                 if (filldir
 173                                     (dirent, local_buf, d_reclen, d_off, d_ino,
 174                                      DT_UNKNOWN) < 0) {
 175                                         if (local_buf != small_buf) {
 176                                                 kfree(local_buf);
 177                                         }
 178                                         goto end;
 179                                 }
 180                                 if (local_buf != small_buf) {
 181                                         kfree(local_buf);
 182                                 }
 183                                 // next entry should be looked for with such offset
 184                                 next_pos = deh_offset(deh) + 1;
 185
 186                                 if (item_moved(&tmp_ih, &path_to_entry)) {
 187                                         goto research;
 188                                 }
 189                         }       /* for */
 190                 }
 191
 192                 if (item_num != B_NR_ITEMS(bh) - 1)
 193                         // end of directory has been reached
 194                         goto end;
 195
 196                 /* item we went through is last item of node. Using right
 197                    delimiting key check is it directory end */
 198                 rkey = get_rkey(&path_to_entry, inode->i_sb);
 199                 if (!comp_le_keys(rkey, &MIN_KEY)) {
 200                         /* set pos_key to key, that is the smallest and greater
 201                            that key of the last entry in the item */
 202                         set_cpu_key_k_offset(&pos_key, next_pos);
 203                         continue;
 204                 }
 205
 206                 if (COMP_SHORT_KEYS(rkey, &pos_key)) {
 207                         // end of directory has been reached
 208                         goto end;
 209                 }
 210
 211                 /* directory continues in the right neighboring block */
 212                 set_cpu_key_k_offset(&pos_key,
 213                                      le_key_k_offset(KEY_FORMAT_3_5, rkey));
 214
 215         }                       /* while */
 216
 217       end:
 218         filp->f_pos = next_pos;
 219         pathrelse(&path_to_entry);
 220         reiserfs_check_path(&path_to_entry);
 221       out:
 222         reiserfs_write_unlock(inode->i_sb);
 223         return ret;
 224 }
 225
 226 /* compose directory item containing "." and ".." entries (entries are
 227    not aligned to 4 byte boundary) */
 228 /* the last four params are LE */
 229 void make_empty_dir_item_v1(char *body, __le32 dirid, __le32 objid,
 230                             __le32 par_dirid, __le32 par_objid)
 231 {
 232         struct reiserfs_de_head *deh;
 233
 234         memset(body, 0, EMPTY_DIR_SIZE_V1);
 235         deh = (struct reiserfs_de_head *)body;
 236
 237         /* direntry header of "." */
 238         put_deh_offset(&(deh[0]), DOT_OFFSET);
 239         /* these two are from make_le_item_head, and are are LE */
 240         deh[0].deh_dir_id = dirid;
 241         deh[0].deh_objectid = objid;
 242         deh[0].deh_state = 0;   /* Endian safe if 0 */
 243         put_deh_location(&(deh[0]), EMPTY_DIR_SIZE_V1 - strlen("."));
 244         mark_de_visible(&(deh[0]));
 245
 246         /* direntry header of ".." */
 247         put_deh_offset(&(deh[1]), DOT_DOT_OFFSET);
 248         /* key of ".." for the root directory */
 249         /* these two are from the inode, and are are LE */
 250         deh[1].deh_dir_id = par_dirid;
 251         deh[1].deh_objectid = par_objid;
 252         deh[1].deh_state = 0;   /* Endian safe if 0 */
 253         put_deh_location(&(deh[1]), deh_location(&(deh[0])) - strlen(".."));
 254         mark_de_visible(&(deh[1]));
 255
 256         /* copy ".." and "." */
 257         memcpy(body + deh_location(&(deh[0])), ".", 1);
 258         memcpy(body + deh_location(&(deh[1])), "..", 2);
 259 }
 260
 261 /* compose directory item containing "." and ".." entries */
 262 void make_empty_dir_item(char *body, __le32 dirid, __le32 objid,
 263                          __le32 par_dirid, __le32 par_objid)
 264 {
 265         struct reiserfs_de_head *deh;
 266
 267         memset(body, 0, EMPTY_DIR_SIZE);
 268         deh = (struct reiserfs_de_head *)body;
 269
 270         /* direntry header of "." */
 271         put_deh_offset(&(deh[0]), DOT_OFFSET);
 272         /* these two are from make_le_item_head, and are are LE */
 273         deh[0].deh_dir_id = dirid;
 274         deh[0].deh_objectid = objid;
 275         deh[0].deh_state = 0;   /* Endian safe if 0 */
 276         put_deh_location(&(deh[0]), EMPTY_DIR_SIZE - ROUND_UP(strlen(".")));
 277         mark_de_visible(&(deh[0]));
 278
 279         /* direntry header of ".." */
 280         put_deh_offset(&(deh[1]), DOT_DOT_OFFSET);
 281         /* key of ".." for the root directory */
 282         /* these two are from the inode, and are are LE */
 283         deh[1].deh_dir_id = par_dirid;
 284         deh[1].deh_objectid = par_objid;
 285         deh[1].deh_state = 0;   /* Endian safe if 0 */
 286         put_deh_location(&(deh[1]),
 287                          deh_location(&(deh[0])) - ROUND_UP(strlen("..")));
 288         mark_de_visible(&(deh[1]));
 289
 290         /* copy ".." and "." */
 291         memcpy(body + deh_location(&(deh[0])), ".", 1);
 292         memcpy(body + deh_location(&(deh[1])), "..", 2);
 293 }