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 <asm/uaccess.h>
  17 #include <linux/errno.h>
  18 #include <linux/fs.h>
  19 #include <linux/kernel.h>
  20 #include <linux/affs_fs.h>
  21 #include <linux/stat.h>
  22 #include <linux/string.h>
  23 #include <linux/mm.h>
  24 #include <linux/amigaffs.h>
  25 #include <linux/smp_lock.h>
  26 #include <linux/buffer_head.h>
  27
  28 static int affs_readdir(struct file *, void *, filldir_t);
  29
  30 struct file_operations affs_dir_operations = {
  31         .read           = generic_read_dir,
  32         .readdir        = affs_readdir,
  33         .fsync          = file_fsync,
  34 };
  35
  36 /*
  37  * directories can handle most operations...
  38  */
  39 struct inode_operations affs_dir_inode_operations = {
  40         .create         = affs_create,
  41         .lookup         = affs_lookup,
  42         .link           = affs_link,
  43         .unlink         = affs_unlink,
  44         .symlink        = affs_symlink,
  45         .mkdir          = affs_mkdir,
  46         .rmdir          = affs_rmdir,
  47         .rename         = affs_rename,
  48         .setattr        = affs_notify_change,
  49 };
  50
  51 static int
  52 affs_readdir(struct file *filp, void *dirent, filldir_t filldir)
  53 {
  54         struct inode            *inode = filp->f_dentry->d_inode;
  55         struct super_block      *sb = inode->i_sb;
  56         struct buffer_head      *dir_bh;
  57         struct buffer_head      *fh_bh;
  58         unsigned char           *name;
  59         int                      namelen;
  60         u32                      i;
  61         int                      hash_pos;
  62         int                      chain_pos;
  63         u32                      f_pos;
  64         u32                      ino;
  65         int                      stored;
  66         int                      res;
  67
  68         pr_debug("AFFS: readdir(ino=%lu,f_pos=%lx)\n",inode->i_ino,(unsigned long)filp->f_pos);
  69
  70         stored = 0;
  71         res    = -EIO;
  72         dir_bh = NULL;
  73         fh_bh  = NULL;
  74         f_pos  = filp->f_pos;
  75
  76         if (f_pos == 0) {
  77                 filp->private_data = (void *)0;
  78                 if (filldir(dirent, ".", 1, f_pos, inode->i_ino, DT_DIR) < 0)
  79                         return 0;
  80                 filp->f_pos = f_pos = 1;
  81                 stored++;
  82         }
  83         if (f_pos == 1) {
  84                 if (filldir(dirent, "..", 2, f_pos, parent_ino(filp->f_dentry), DT_DIR) < 0)
  85                         return stored;
  86                 filp->f_pos = f_pos = 2;
  87                 stored++;
  88         }
  89
  90         affs_lock_dir(inode);
  91         chain_pos = (f_pos - 2) & 0xffff;
  92         hash_pos  = (f_pos - 2) >> 16;
  93         if (chain_pos == 0xffff) {
  94                 affs_warning(sb, "readdir", "More than 65535 entries in chain");
  95                 chain_pos = 0;
  96                 hash_pos++;
  97                 filp->f_pos = ((hash_pos << 16) | chain_pos) + 2;
  98         }
  99         dir_bh = affs_bread(sb, inode->i_ino);
 100         if (!dir_bh)
 101                 goto readdir_out;
 102
 103         /* If the directory hasn't changed since the last call to readdir(),
 104          * we can jump directly to where we left off.
 105          */
 106         ino = (u32)(long)filp->private_data;
 107         if (ino && filp->f_version == inode->i_version) {
 108                 pr_debug("AFFS: readdir() left off=%d\n", ino);
 109                 goto inside;
 110         }
 111
 112         ino = be32_to_cpu(AFFS_HEAD(dir_bh)->table[hash_pos]);
 113         for (i = 0; ino && i < chain_pos; i++) {
 114                 fh_bh = affs_bread(sb, ino);
 115                 if (!fh_bh) {
 116                         affs_error(sb, "readdir","Cannot read block %d", i);
 117                         goto readdir_out;
 118                 }
 119                 ino = be32_to_cpu(AFFS_TAIL(sb, fh_bh)->hash_chain);
 120                 affs_brelse(fh_bh);
 121                 fh_bh = NULL;
 122         }
 123         if (ino)
 124                 goto inside;
 125         hash_pos++;
 126
 127         for (; hash_pos < AFFS_SB(sb)->s_hashsize; hash_pos++) {
 128                 ino = be32_to_cpu(AFFS_HEAD(dir_bh)->table[hash_pos]);
 129                 if (!ino)
 130                         continue;
 131                 f_pos = (hash_pos << 16) + 2;
 132 inside:
 133                 do {
 134                         fh_bh = affs_bread(sb, ino);
 135                         if (!fh_bh) {
 136                                 affs_error(sb, "readdir","Cannot read block %d", ino);
 137                                 goto readdir_done;
 138                         }
 139
 140                         namelen = min(AFFS_TAIL(sb, fh_bh)->name[0], (u8)30);
 141                         name = AFFS_TAIL(sb, fh_bh)->name + 1;
 142                         pr_debug("AFFS: readdir(): filldir(\"%.*s\", ino=%u), hash=%d, f_pos=%x\n",
 143                                  namelen, name, ino, hash_pos, f_pos);
 144                         if (filldir(dirent, name, namelen, f_pos, ino, DT_UNKNOWN) < 0)
 145                                 goto readdir_done;
 146                         stored++;
 147                         f_pos++;
 148                         ino = be32_to_cpu(AFFS_TAIL(sb, fh_bh)->hash_chain);
 149                         affs_brelse(fh_bh);
 150                         fh_bh = NULL;
 151                 } while (ino);
 152         }
 153 readdir_done:
 154         filp->f_pos = f_pos;
 155         filp->f_version = inode->i_version;
 156         filp->private_data = (void *)(long)ino;
 157         res = stored;
 158
 159 readdir_out:
 160         affs_brelse(dir_bh);
 161         affs_brelse(fh_bh);
 162         affs_unlock_dir(inode);
 163         pr_debug("AFFS: readdir()=%d\n", stored);
 164         return res;
 165 }