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 "reiserfs.h"
   9 #include <linux/stat.h>
  10 #include <linux/buffer_head.h>
  11 #include <linux/slab.h>
  12 #include <linux/uaccess.h>
  13
  14 extern const struct reiserfs_key MIN_KEY;
  15
  16 static int reiserfs_readdir(struct file *, struct dir_context *);
  17 static int reiserfs_dir_fsync(struct file *filp, loff_t start, loff_t end,
  18                               int datasync);
  19
  20 const struct file_operations reiserfs_dir_operations = {
  21         .llseek = generic_file_llseek,
  22         .read = generic_read_dir,
  23         .iterate_shared = reiserfs_readdir,
  24         .fsync = reiserfs_dir_fsync,
  25         .unlocked_ioctl = reiserfs_ioctl,
  26 #ifdef CONFIG_COMPAT
  27         .compat_ioctl = reiserfs_compat_ioctl,
  28 #endif
  29 };
  30
  31 static int reiserfs_dir_fsync(struct file *filp, loff_t start, loff_t end,
  32                               int datasync)
  33 {
  34         struct inode *inode = filp->f_mapping->host;
  35         int err;
  36
  37         err = filemap_write_and_wait_range(inode->i_mapping, start, end);
  38         if (err)
  39                 return err;
  40
  41         inode_lock(inode);
  42         reiserfs_write_lock(inode->i_sb);
  43         err = reiserfs_commit_for_inode(inode);
  44         reiserfs_write_unlock(inode->i_sb);
  45         inode_unlock(inode);
  46         if (err < 0)
  47                 return err;
  48         return 0;
  49 }
  50
  51 #define store_ih(where,what) copy_item_head (where, what)
  52
  53 static inline bool is_privroot_deh(struct inode *dir, struct reiserfs_de_head *deh)
  54 {
  55         struct dentry *privroot = REISERFS_SB(dir->i_sb)->priv_root;
  56         return (d_really_is_positive(privroot) &&
  57                 deh->deh_objectid == INODE_PKEY(d_inode(privroot))->k_objectid);
  58 }
  59
  60 int reiserfs_readdir_inode(struct inode *inode, struct dir_context *ctx)
  61 {
  62
  63         /* key of current position in the directory (key of directory entry) */
  64         struct cpu_key pos_key;
  65
  66         INITIALIZE_PATH(path_to_entry);
  67         struct buffer_head *bh;
  68         int item_num, entry_num;
  69         const struct reiserfs_key *rkey;
  70         struct item_head *ih, tmp_ih;
  71         int search_res;
  72         char *local_buf;
  73         loff_t next_pos;
  74         char small_buf[32];     /* avoid kmalloc if we can */
  75         struct reiserfs_dir_entry de;
  76         int ret = 0;
  77         int depth;
  78
  79         reiserfs_write_lock(inode->i_sb);
  80
  81         reiserfs_check_lock_depth(inode->i_sb, "readdir");
  82
  83         /*
  84          * form key for search the next directory entry using
  85          * f_pos field of file structure
  86          */
  87         make_cpu_key(&pos_key, inode, ctx->pos ?: DOT_OFFSET, TYPE_DIRENTRY, 3);
  88         next_pos = cpu_key_k_offset(&pos_key);
  89
  90         path_to_entry.reada = PATH_READA;
  91         while (1) {
  92 research:
  93                 /*
  94                  * search the directory item, containing entry with
  95                  * specified key
  96                  */
  97                 search_res =
  98                     search_by_entry_key(inode->i_sb, &pos_key, &path_to_entry,
  99                                         &de);
 100                 if (search_res == IO_ERROR) {
 101                         /*
 102                          * FIXME: we could just skip part of directory
 103                          * which could not be read
 104                          */
 105                         ret = -EIO;
 106                         goto out;
 107                 }
 108                 entry_num = de.de_entry_num;
 109                 bh = de.de_bh;
 110                 item_num = de.de_item_num;
 111                 ih = de.de_ih;
 112                 store_ih(&tmp_ih, ih);
 113
 114                 /* we must have found item, that is item of this directory, */
 115                 RFALSE(COMP_SHORT_KEYS(&ih->ih_key, &pos_key),
 116                        "vs-9000: found item %h does not match to dir we readdir %K",
 117                        ih, &pos_key);
 118                 RFALSE(item_num > B_NR_ITEMS(bh) - 1,
 119                        "vs-9005 item_num == %d, item amount == %d",
 120                        item_num, B_NR_ITEMS(bh));
 121
 122                 /*
 123                  * and entry must be not more than number of entries
 124                  * in the item
 125                  */
 126                 RFALSE(ih_entry_count(ih) < entry_num,
 127                        "vs-9010: entry number is too big %d (%d)",
 128                        entry_num, ih_entry_count(ih));
 129
 130                 /*
 131                  * go through all entries in the directory item beginning
 132                  * from the entry, that has been found
 133                  */
 134                 if (search_res == POSITION_FOUND
 135                     || entry_num < ih_entry_count(ih)) {
 136                         struct reiserfs_de_head *deh =
 137                             B_I_DEH(bh, ih) + entry_num;
 138
 139                         for (; entry_num < ih_entry_count(ih);
 140                              entry_num++, deh++) {
 141                                 int d_reclen;
 142                                 char *d_name;
 143                                 ino_t d_ino;
 144                                 loff_t cur_pos = deh_offset(deh);
 145
 146                                 /* it is hidden entry */
 147                                 if (!de_visible(deh))
 148                                         continue;
 149                                 d_reclen = entry_length(bh, ih, entry_num);
 150                                 d_name = B_I_DEH_ENTRY_FILE_NAME(bh, ih, deh);
 151
 152                                 if (d_reclen <= 0 ||
 153                                     d_name + d_reclen > bh->b_data + bh->b_size) {
 154                                         /*
 155                                          * There is corrupted data in entry,
 156                                          * We'd better stop here
 157                                          */
 158                                         pathrelse(&path_to_entry);
 159                                         ret = -EIO;
 160                                         goto out;
 161                                 }
 162
 163                                 if (!d_name[d_reclen - 1])
 164                                         d_reclen = strlen(d_name);
 165
 166                                 /* too big to send back to VFS */
 167                                 if (d_reclen >
 168                                     REISERFS_MAX_NAME(inode->i_sb->
 169                                                       s_blocksize)) {
 170                                         continue;
 171                                 }
 172
 173                                 /* Ignore the .reiserfs_priv entry */
 174                                 if (is_privroot_deh(inode, deh))
 175                                         continue;
 176
 177                                 ctx->pos = deh_offset(deh);
 178                                 d_ino = deh_objectid(deh);
 179                                 if (d_reclen <= 32) {
 180                                         local_buf = small_buf;
 181                                 } else {
 182                                         local_buf = kmalloc(d_reclen,
 183                                                             GFP_NOFS);
 184                                         if (!local_buf) {
 185                                                 pathrelse(&path_to_entry);
 186                                                 ret = -ENOMEM;
 187                                                 goto out;
 188                                         }
 189                                         if (item_moved(&tmp_ih, &path_to_entry)) {
 190                                                 kfree(local_buf);
 191                                                 goto research;
 192                                         }
 193                                 }
 194
 195                                 /*
 196                                  * Note, that we copy name to user space via
 197                                  * temporary buffer (local_buf) because
 198                                  * filldir will block if user space buffer is
 199                                  * swapped out. At that time entry can move to
 200                                  * somewhere else
 201                                  */
 202                                 memcpy(local_buf, d_name, d_reclen);
 203
 204                                 /*
 205                                  * Since filldir might sleep, we can release
 206                                  * the write lock here for other waiters
 207                                  */
 208                                 depth = reiserfs_write_unlock_nested(inode->i_sb);
 209                                 if (!dir_emit
 210                                     (ctx, local_buf, d_reclen, d_ino,
 211                                      DT_UNKNOWN)) {
 212                                         reiserfs_write_lock_nested(inode->i_sb, depth);
 213                                         if (local_buf != small_buf) {
 214                                                 kfree(local_buf);
 215                                         }
 216                                         goto end;
 217                                 }
 218                                 reiserfs_write_lock_nested(inode->i_sb, depth);
 219                                 if (local_buf != small_buf) {
 220                                         kfree(local_buf);
 221                                 }
 222
 223                                 /* deh_offset(deh) may be invalid now. */
 224                                 next_pos = cur_pos + 1;
 225
 226                                 if (item_moved(&tmp_ih, &path_to_entry)) {
 227                                         set_cpu_key_k_offset(&pos_key,
 228                                                              next_pos);
 229                                         goto research;
 230                                 }
 231                         }       /* for */
 232                 }
 233
 234                 /* end of directory has been reached */
 235                 if (item_num != B_NR_ITEMS(bh) - 1)
 236                         goto end;
 237
 238                 /*
 239                  * item we went through is last item of node. Using right
 240                  * delimiting key check is it directory end
 241                  */
 242                 rkey = get_rkey(&path_to_entry, inode->i_sb);
 243                 if (!comp_le_keys(rkey, &MIN_KEY)) {
 244                         /*
 245                          * set pos_key to key, that is the smallest and greater
 246                          * that key of the last entry in the item
 247                          */
 248                         set_cpu_key_k_offset(&pos_key, next_pos);
 249                         continue;
 250                 }
 251
 252                 /* end of directory has been reached */
 253                 if (COMP_SHORT_KEYS(rkey, &pos_key)) {
 254                         goto end;
 255                 }
 256
 257                 /* directory continues in the right neighboring block */
 258                 set_cpu_key_k_offset(&pos_key,
 259                                      le_key_k_offset(KEY_FORMAT_3_5, rkey));
 260
 261         }                       /* while */
 262
 263 end:
 264         ctx->pos = next_pos;
 265         pathrelse(&path_to_entry);
 266         reiserfs_check_path(&path_to_entry);
 267 out:
 268         reiserfs_write_unlock(inode->i_sb);
 269         return ret;
 270 }
 271
 272 static int reiserfs_readdir(struct file *file, struct dir_context *ctx)
 273 {
 274         return reiserfs_readdir_inode(file_inode(file), ctx);
 275 }
 276
 277 /*
 278  * compose directory item containing "." and ".." entries (entries are
 279  * not aligned to 4 byte boundary)
 280  */
 281 void make_empty_dir_item_v1(char *body, __le32 dirid, __le32 objid,
 282                             __le32 par_dirid, __le32 par_objid)
 283 {
 284         struct reiserfs_de_head *dot, *dotdot;
 285
 286         memset(body, 0, EMPTY_DIR_SIZE_V1);
 287         dot = (struct reiserfs_de_head *)body;
 288         dotdot = dot + 1;
 289
 290         /* direntry header of "." */
 291         put_deh_offset(dot, DOT_OFFSET);
 292         /* these two are from make_le_item_head, and are are LE */
 293         dot->deh_dir_id = dirid;
 294         dot->deh_objectid = objid;
 295         dot->deh_state = 0;     /* Endian safe if 0 */
 296         put_deh_location(dot, EMPTY_DIR_SIZE_V1 - strlen("."));
 297         mark_de_visible(dot);
 298
 299         /* direntry header of ".." */
 300         put_deh_offset(dotdot, DOT_DOT_OFFSET);
 301         /* key of ".." for the root directory */
 302         /* these two are from the inode, and are are LE */
 303         dotdot->deh_dir_id = par_dirid;
 304         dotdot->deh_objectid = par_objid;
 305         dotdot->deh_state = 0;  /* Endian safe if 0 */
 306         put_deh_location(dotdot, deh_location(dot) - strlen(".."));
 307         mark_de_visible(dotdot);
 308
 309         /* copy ".." and "." */
 310         memcpy(body + deh_location(dot), ".", 1);
 311         memcpy(body + deh_location(dotdot), "..", 2);
 312 }
 313
 314 /* compose directory item containing "." and ".." entries */
 315 void make_empty_dir_item(char *body, __le32 dirid, __le32 objid,
 316                          __le32 par_dirid, __le32 par_objid)
 317 {
 318         struct reiserfs_de_head *dot, *dotdot;
 319
 320         memset(body, 0, EMPTY_DIR_SIZE);
 321         dot = (struct reiserfs_de_head *)body;
 322         dotdot = dot + 1;
 323
 324         /* direntry header of "." */
 325         put_deh_offset(dot, DOT_OFFSET);
 326         /* these two are from make_le_item_head, and are are LE */
 327         dot->deh_dir_id = dirid;
 328         dot->deh_objectid = objid;
 329         dot->deh_state = 0;     /* Endian safe if 0 */
 330         put_deh_location(dot, EMPTY_DIR_SIZE - ROUND_UP(strlen(".")));
 331         mark_de_visible(dot);
 332
 333         /* direntry header of ".." */
 334         put_deh_offset(dotdot, DOT_DOT_OFFSET);
 335         /* key of ".." for the root directory */
 336         /* these two are from the inode, and are are LE */
 337         dotdot->deh_dir_id = par_dirid;
 338         dotdot->deh_objectid = par_objid;
 339         dotdot->deh_state = 0;  /* Endian safe if 0 */
 340         put_deh_location(dotdot, deh_location(dot) - ROUND_UP(strlen("..")));
 341         mark_de_visible(dotdot);
 342
 343         /* copy ".." and "." */
 344         memcpy(body + deh_location(dot), ".", 1);
 345         memcpy(body + deh_location(dotdot), "..", 2);
 346 }