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