LXR linux/fs/affs/dir.c

   1/*
   2 *  linux/fs/affs/dir.c
   3 *
   4 *  (c) 1996  Hans-Joachim Widmaier - Rewritten
   5 *
   6 *  (C) 1993  Ray Burr - Modified for Amiga FFS filesystem.
   7 *
   8 *  (C) 1992  Eric Youngdale Modified for ISO 9660 filesystem.
   9 *
  10 *  (C) 1991  Linus Torvalds - minix filesystem
  11 *
  12 *  affs directory handling functions
  13 *
  14 */
  15
  16#include "affs.h"
  17
  18static int affs_readdir(struct file *, void *, filldir_t);
  19
  20const struct file_operations affs_dir_operations = {
  21        .read           = generic_read_dir,
  22        .readdir        = affs_readdir,
  23        .fsync          = file_fsync,
  24};
  25
  26/*
  27 * directories can handle most operations...
  28 */
  29const struct inode_operations affs_dir_inode_operations = {
  30        .create         = affs_create,
  31        .lookup         = affs_lookup,
  32        .link           = affs_link,
  33        .unlink         = affs_unlink,
  34        .symlink        = affs_symlink,
  35        .mkdir          = affs_mkdir,
  36        .rmdir          = affs_rmdir,
  37        .rename         = affs_rename,
  38        .setattr        = affs_notify_change,
  39};
  40
  41static int
  42affs_readdir(struct file *filp, void *dirent, filldir_t filldir)
  43{
  44        struct inode            *inode = filp->f_path.dentry->d_inode;
  45        struct super_block      *sb = inode->i_sb;
  46        struct buffer_head      *dir_bh;
  47        struct buffer_head      *fh_bh;
  48        unsigned char           *name;
  49        int                      namelen;
  50        u32                      i;
  51        int                      hash_pos;
  52        int                      chain_pos;
  53        u32                      f_pos;
  54        u32                      ino;
  55        int                      stored;
  56        int                      res;
  57
  58        pr_debug("AFFS: readdir(ino=%lu,f_pos=%lx)\n",inode->i_ino,(unsigned long)filp->f_pos);
  59
  60        stored = 0;
  61        res    = -EIO;
  62        dir_bh = NULL;
  63        fh_bh  = NULL;
  64        f_pos  = filp->f_pos;
  65
  66        if (f_pos == 0) {
  67                filp->private_data = (void *)0;
  68                if (filldir(dirent, ".", 1, f_pos, inode->i_ino, DT_DIR) < 0)
  69                        return 0;
  70                filp->f_pos = f_pos = 1;
  71                stored++;
  72        }
  73        if (f_pos == 1) {
  74                if (filldir(dirent, "..", 2, f_pos, parent_ino(filp->f_path.dentry), DT_DIR) < 0)
  75                        return stored;
  76                filp->f_pos = f_pos = 2;
  77                stored++;
  78        }
  79
  80        affs_lock_dir(inode);
  81        chain_pos = (f_pos - 2) & 0xffff;
  82        hash_pos  = (f_pos - 2) >> 16;
  83        if (chain_pos == 0xffff) {
  84                affs_warning(sb, "readdir", "More than 65535 entries in chain");
  85                chain_pos = 0;
  86                hash_pos++;
  87                filp->f_pos = ((hash_pos << 16) | chain_pos) + 2;
  88        }
  89        dir_bh = affs_bread(sb, inode->i_ino);
  90        if (!dir_bh)
  91                goto readdir_out;
  92
  93        /* If the directory hasn't changed since the last call to readdir(),
  94         * we can jump directly to where we left off.
  95         */
  96        ino = (u32)(long)filp->private_data;
  97        if (ino && filp->f_version == inode->i_version) {
  98                pr_debug("AFFS: readdir() left off=%d\n", ino);
  99                goto inside;
 100        }
 101
 102        ino = be32_to_cpu(AFFS_HEAD(dir_bh)->table[hash_pos]);
 103        for (i = 0; ino && i < chain_pos; i++) {
 104                fh_bh = affs_bread(sb, ino);
 105                if (!fh_bh) {
 106                        affs_error(sb, "readdir","Cannot read block %d", i);
 107                        goto readdir_out;
 108                }
 109                ino = be32_to_cpu(AFFS_TAIL(sb, fh_bh)->hash_chain);
 110                affs_brelse(fh_bh);
 111                fh_bh = NULL;
 112        }
 113        if (ino)
 114                goto inside;
 115        hash_pos++;
 116
 117        for (; hash_pos < AFFS_SB(sb)->s_hashsize; hash_pos++) {
 118                ino = be32_to_cpu(AFFS_HEAD(dir_bh)->table[hash_pos]);
 119                if (!ino)
 120                        continue;
 121                f_pos = (hash_pos << 16) + 2;
 122inside:
 123                do {
 124                        fh_bh = affs_bread(sb, ino);
 125                        if (!fh_bh) {
 126                                affs_error(sb, "readdir","Cannot read block %d", ino);
 127                                goto readdir_done;
 128                        }
 129
 130                        namelen = min(AFFS_TAIL(sb, fh_bh)->name[0], (u8)30);
 131                        name = AFFS_TAIL(sb, fh_bh)->name + 1;
 132                        pr_debug("AFFS: readdir(): filldir(\"%.*s\", ino=%u), hash=%d, f_pos=%x\n",
 133                                 namelen, name, ino, hash_pos, f_pos);
 134                        if (filldir(dirent, name, namelen, f_pos, ino, DT_UNKNOWN) < 0)
 135                                goto readdir_done;
 136                        stored++;
 137                        f_pos++;
 138                        ino = be32_to_cpu(AFFS_TAIL(sb, fh_bh)->hash_chain);
 139                        affs_brelse(fh_bh);
 140                        fh_bh = NULL;
 141                } while (ino);
 142        }
 143readdir_done:
 144        filp->f_pos = f_pos;
 145        filp->f_version = inode->i_version;
 146        filp->private_data = (void *)(long)ino;
 147        res = stored;
 148
 149readdir_out:
 150        affs_brelse(dir_bh);
 151        affs_brelse(fh_bh);
 152        affs_unlock_dir(inode);
 153        pr_debug("AFFS: readdir()=%d\n", stored);
 154        return res;
 155}
 156