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 <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, 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         .readdir = 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         mutex_lock(&inode->i_mutex);
  42         reiserfs_write_lock(inode->i_sb);
  43         err = reiserfs_commit_for_inode(inode);
  44         reiserfs_write_unlock(inode->i_sb);
  45         mutex_unlock(&inode->i_mutex);
  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 dentry *dir,
  54                                    struct reiserfs_de_head *deh)
  55 {
  56         struct dentry *privroot = REISERFS_SB(dir->d_sb)->priv_root;
  57         return (dir == dir->d_parent && privroot->d_inode &&
  58                 deh->deh_objectid == INODE_PKEY(privroot->d_inode)->k_objectid);
  59 }
  60
  61 int reiserfs_readdir_dentry(struct dentry *dentry, void *dirent,
  62                            filldir_t filldir, loff_t *pos)
  63 {
  64         struct inode *inode = dentry->d_inode;
  65         struct cpu_key pos_key; /* key of current position in the directory (key of directory entry) */
  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
  78         reiserfs_write_lock(inode->i_sb);
  79
  80         reiserfs_check_lock_depth(inode->i_sb, "readdir");
  81
  82         /* form key for search the next directory entry using f_pos field of
  83            file structure */
  84         make_cpu_key(&pos_key, inode, *pos ?: DOT_OFFSET, TYPE_DIRENTRY, 3);
  85         next_pos = cpu_key_k_offset(&pos_key);
  86
  87         path_to_entry.reada = PATH_READA;
  88         while (1) {
  89               research:
  90                 /* search the directory item, containing entry with specified key */
  91                 search_res =
  92                     search_by_entry_key(inode->i_sb, &pos_key, &path_to_entry,
  93                                         &de);
  94                 if (search_res == IO_ERROR) {
  95                         // FIXME: we could just skip part of directory which could
  96                         // not be read
  97                         ret = -EIO;
  98                         goto out;
  99                 }
 100                 entry_num = de.de_entry_num;
 101                 bh = de.de_bh;
 102                 item_num = de.de_item_num;
 103                 ih = de.de_ih;
 104                 store_ih(&tmp_ih, ih);
 105
 106                 /* we must have found item, that is item of this directory, */
 107                 RFALSE(COMP_SHORT_KEYS(&(ih->ih_key), &pos_key),
 108                        "vs-9000: found item %h does not match to dir we readdir %K",
 109                        ih, &pos_key);
 110                 RFALSE(item_num > B_NR_ITEMS(bh) - 1,
 111                        "vs-9005 item_num == %d, item amount == %d",
 112                        item_num, B_NR_ITEMS(bh));
 113
 114                 /* and entry must be not more than number of entries in the item */
 115                 RFALSE(I_ENTRY_COUNT(ih) < entry_num,
 116                        "vs-9010: entry number is too big %d (%d)",
 117                        entry_num, I_ENTRY_COUNT(ih));
 118
 119                 if (search_res == POSITION_FOUND
 120                     || entry_num < I_ENTRY_COUNT(ih)) {
 121                         /* go through all entries in the directory item beginning from the entry, that has been found */
 122                         struct reiserfs_de_head *deh =
 123                             B_I_DEH(bh, ih) + entry_num;
 124
 125                         for (; entry_num < I_ENTRY_COUNT(ih);
 126                              entry_num++, deh++) {
 127                                 int d_reclen;
 128                                 char *d_name;
 129                                 off_t d_off;
 130                                 ino_t d_ino;
 131
 132                                 if (!de_visible(deh))
 133                                         /* it is hidden entry */
 134                                         continue;
 135                                 d_reclen = entry_length(bh, ih, entry_num);
 136                                 d_name = B_I_DEH_ENTRY_FILE_NAME(bh, ih, deh);
 137
 138                                 if (d_reclen <= 0 ||
 139                                     d_name + d_reclen > bh->b_data + bh->b_size) {
 140                                         /* There is corrupted data in entry,
 141                                          * We'd better stop here */
 142                                         pathrelse(&path_to_entry);
 143                                         ret = -EIO;
 144                                         goto out;
 145                                 }
 146
 147                                 if (!d_name[d_reclen - 1])
 148                                         d_reclen = strlen(d_name);
 149
 150                                 if (d_reclen >
 151                                     REISERFS_MAX_NAME(inode->i_sb->
 152                                                       s_blocksize)) {
 153                                         /* too big to send back to VFS */
 154                                         continue;
 155                                 }
 156
 157                                 /* Ignore the .reiserfs_priv entry */
 158                                 if (is_privroot_deh(dentry, deh))
 159                                         continue;
 160
 161                                 d_off = deh_offset(deh);
 162                                 *pos = d_off;
 163                                 d_ino = deh_objectid(deh);
 164                                 if (d_reclen <= 32) {
 165                                         local_buf = small_buf;
 166                                 } else {
 167                                         local_buf = kmalloc(d_reclen,
 168                                                             GFP_NOFS);
 169                                         if (!local_buf) {
 170                                                 pathrelse(&path_to_entry);
 171                                                 ret = -ENOMEM;
 172                                                 goto out;
 173                                         }
 174                                         if (item_moved(&tmp_ih, &path_to_entry)) {
 175                                                 kfree(local_buf);
 176                                                 goto research;
 177                                         }
 178                                 }
 179                                 // Note, that we copy name to user space via temporary
 180                                 // buffer (local_buf) because filldir will block if
 181                                 // user space buffer is swapped out. At that time
 182                                 // entry can move to somewhere else
 183                                 memcpy(local_buf, d_name, d_reclen);
 184
 185                                 /*
 186                                  * Since filldir might sleep, we can release
 187                                  * the write lock here for other waiters
 188                                  */
 189                                 reiserfs_write_unlock(inode->i_sb);
 190                                 if (filldir
 191                                     (dirent, local_buf, d_reclen, d_off, d_ino,
 192                                      DT_UNKNOWN) < 0) {
 193                                         reiserfs_write_lock(inode->i_sb);
 194                                         if (local_buf != small_buf) {
 195                                                 kfree(local_buf);
 196                                         }
 197                                         goto end;
 198                                 }
 199                                 reiserfs_write_lock(inode->i_sb);
 200                                 if (local_buf != small_buf) {
 201                                         kfree(local_buf);
 202                                 }
 203                                 // next entry should be looked for with such offset
 204                                 next_pos = deh_offset(deh) + 1;
 205
 206                                 if (item_moved(&tmp_ih, &path_to_entry)) {
 207                                         goto research;
 208                                 }
 209                         }       /* for */
 210                 }
 211
 212                 if (item_num != B_NR_ITEMS(bh) - 1)
 213                         // end of directory has been reached
 214                         goto end;
 215
 216                 /* item we went through is last item of node. Using right
 217                    delimiting key check is it directory end */
 218                 rkey = get_rkey(&path_to_entry, inode->i_sb);
 219                 if (!comp_le_keys(rkey, &MIN_KEY)) {
 220                         /* set pos_key to key, that is the smallest and greater
 221                            that key of the last entry in the item */
 222                         set_cpu_key_k_offset(&pos_key, next_pos);
 223                         continue;
 224                 }
 225
 226                 if (COMP_SHORT_KEYS(rkey, &pos_key)) {
 227                         // end of directory has been reached
 228                         goto end;
 229                 }
 230
 231                 /* directory continues in the right neighboring block */
 232                 set_cpu_key_k_offset(&pos_key,
 233                                      le_key_k_offset(KEY_FORMAT_3_5, rkey));
 234
 235         }                       /* while */
 236
 237 end:
 238         *pos = next_pos;
 239         pathrelse(&path_to_entry);
 240         reiserfs_check_path(&path_to_entry);
 241 out:
 242         reiserfs_write_unlock(inode->i_sb);
 243         return ret;
 244 }
 245
 246 static int reiserfs_readdir(struct file *file, void *dirent, filldir_t filldir)
 247 {
 248         struct dentry *dentry = file->f_path.dentry;
 249         return reiserfs_readdir_dentry(dentry, dirent, filldir, &file->f_pos);
 250 }
 251
 252 /* compose directory item containing "." and ".." entries (entries are
 253    not aligned to 4 byte boundary) */
 254 /* the last four params are LE */
 255 void make_empty_dir_item_v1(char *body, __le32 dirid, __le32 objid,
 256                             __le32 par_dirid, __le32 par_objid)
 257 {
 258         struct reiserfs_de_head *deh;
 259
 260         memset(body, 0, EMPTY_DIR_SIZE_V1);
 261         deh = (struct reiserfs_de_head *)body;
 262
 263         /* direntry header of "." */
 264         put_deh_offset(&(deh[0]), DOT_OFFSET);
 265         /* these two are from make_le_item_head, and are are LE */
 266         deh[0].deh_dir_id = dirid;
 267         deh[0].deh_objectid = objid;
 268         deh[0].deh_state = 0;   /* Endian safe if 0 */
 269         put_deh_location(&(deh[0]), EMPTY_DIR_SIZE_V1 - strlen("."));
 270         mark_de_visible(&(deh[0]));
 271
 272         /* direntry header of ".." */
 273         put_deh_offset(&(deh[1]), DOT_DOT_OFFSET);
 274         /* key of ".." for the root directory */
 275         /* these two are from the inode, and are are LE */
 276         deh[1].deh_dir_id = par_dirid;
 277         deh[1].deh_objectid = par_objid;
 278         deh[1].deh_state = 0;   /* Endian safe if 0 */
 279         put_deh_location(&(deh[1]), deh_location(&(deh[0])) - strlen(".."));
 280         mark_de_visible(&(deh[1]));
 281
 282         /* copy ".." and "." */
 283         memcpy(body + deh_location(&(deh[0])), ".", 1);
 284         memcpy(body + deh_location(&(deh[1])), "..", 2);
 285 }
 286
 287 /* compose directory item containing "." and ".." entries */
 288 void make_empty_dir_item(char *body, __le32 dirid, __le32 objid,
 289                          __le32 par_dirid, __le32 par_objid)
 290 {
 291         struct reiserfs_de_head *deh;
 292
 293         memset(body, 0, EMPTY_DIR_SIZE);
 294         deh = (struct reiserfs_de_head *)body;
 295
 296         /* direntry header of "." */
 297         put_deh_offset(&(deh[0]), DOT_OFFSET);
 298         /* these two are from make_le_item_head, and are are LE */
 299         deh[0].deh_dir_id = dirid;
 300         deh[0].deh_objectid = objid;
 301         deh[0].deh_state = 0;   /* Endian safe if 0 */
 302         put_deh_location(&(deh[0]), EMPTY_DIR_SIZE - ROUND_UP(strlen(".")));
 303         mark_de_visible(&(deh[0]));
 304
 305         /* direntry header of ".." */
 306         put_deh_offset(&(deh[1]), DOT_DOT_OFFSET);
 307         /* key of ".." for the root directory */
 308         /* these two are from the inode, and are are LE */
 309         deh[1].deh_dir_id = par_dirid;
 310         deh[1].deh_objectid = par_objid;
 311         deh[1].deh_state = 0;   /* Endian safe if 0 */
 312         put_deh_location(&(deh[1]),
 313                          deh_location(&(deh[0])) - ROUND_UP(strlen("..")));
 314         mark_de_visible(&(deh[1]));
 315
 316         /* copy ".." and "." */
 317         memcpy(body + deh_location(&(deh[0])), ".", 1);
 318         memcpy(body + deh_location(&(deh[1])), "..", 2);
 319 }