LXR linux/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 <linux/slab.h>
  12#include <asm/uaccess.h>
  13
  14extern const struct reiserfs_key MIN_KEY;
  15
  16static int reiserfs_readdir(struct file *, void *, filldir_t);
  17static int reiserfs_dir_fsync(struct file *filp, loff_t start, loff_t end,
  18                              int datasync);
  19
  20const 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
  31static 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
  53static 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
  61int 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
 237end:
 238        *pos = next_pos;
 239        pathrelse(&path_to_entry);
 240        reiserfs_check_path(&path_to_entry);
 241out:
 242        reiserfs_write_unlock(inode->i_sb);
 243        return ret;
 244}
 245
 246static 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 */
 255void 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 */
 288void 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}
 320