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 "reiserfs.h"
   9#include <linux/stat.h>
  10#include <linux/buffer_head.h>
  11#include <linux/slab.h>
  12#include <linux/uaccess.h>
  13
  14extern const struct reiserfs_key MIN_KEY;
  15
  16static int reiserfs_readdir(struct file *, struct dir_context *);
  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        .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
  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 = file_write_and_wait_range(filp, 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
  53static 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
  60int 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) {
  92research:
  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
 263end:
 264        ctx->pos = next_pos;
 265        pathrelse(&path_to_entry);
 266        reiserfs_check_path(&path_to_entry);
 267out:
 268        reiserfs_write_unlock(inode->i_sb);
 269        return ret;
 270}
 271
 272static 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 */
 281void 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 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 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 */
 315void 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 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 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}
 347