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 #define DEBUG 0
  17 #include <asm/uaccess.h>
  18 #include <linux/errno.h>
  19 #include <linux/fs.h>
  20 #include <linux/kernel.h>
  21 #include <linux/affs_fs.h>
  22 #include <linux/stat.h>
  23 #include <linux/string.h>
  24 #include <linux/mm.h>
  25 #include <linux/amigaffs.h>
  26
  27 static int affs_readdir(struct file *, void *, filldir_t);
  28
  29 struct file_operations affs_dir_operations = {
  30         read:           generic_read_dir,
  31         readdir:        affs_readdir,
  32         fsync:          file_fsync,
  33 };
  34
  35 /*
  36  * directories can handle most operations...
  37  */
  38 struct inode_operations affs_dir_inode_operations = {
  39         create:         affs_create,
  40         lookup:         affs_lookup,
  41         link:           affs_link,
  42         unlink:         affs_unlink,
  43         symlink:        affs_symlink,
  44         mkdir:          affs_mkdir,
  45         rmdir:          affs_rmdir,
  46         rename:         affs_rename,
  47         setattr:        affs_notify_change,
  48 };
  49
  50 static int
  51 affs_readdir(struct file *filp, void *dirent, filldir_t filldir)
  52 {
  53         int                      j, namelen;
  54         s32                      i;
  55         int                      hash_pos;
  56         int                      chain_pos;
  57         unsigned long            ino;
  58         int                      stored;
  59         unsigned char           *name;
  60         struct buffer_head      *dir_bh;
  61         struct buffer_head      *fh_bh;
  62         struct inode            *dir;
  63         struct inode            *inode = filp->f_dentry->d_inode;
  64
  65         pr_debug("AFFS: readdir(ino=%lu,f_pos=%lu)\n",inode->i_ino,(unsigned long)filp->f_pos);
  66
  67         stored = 0;
  68         dir_bh = NULL;
  69         fh_bh  = NULL;
  70         dir    = NULL;
  71         ino    = inode->i_ino;
  72
  73         if (filp->f_pos == 0) {
  74                 filp->private_data = (void *)0;
  75                 if (filldir(dirent,".",1,filp->f_pos,inode->i_ino) < 0) {
  76                         return 0;
  77                 }
  78                 ++filp->f_pos;
  79                 stored++;
  80         }
  81         if (filp->f_pos == 1) {
  82                 if (filldir(dirent,"..",2,filp->f_pos,affs_parent_ino(inode)) < 0) {
  83                         return stored;
  84                 }
  85                 filp->f_pos = 2;
  86                 stored++;
  87         }
  88         chain_pos = (filp->f_pos - 2) & 0xffff;
  89         hash_pos  = (filp->f_pos - 2) >> 16;
  90         if (chain_pos == 0xffff) {
  91                 affs_warning(inode->i_sb,"readdir","More than 65535 entries in chain");
  92                 chain_pos = 0;
  93                 hash_pos++;
  94                 filp->f_pos = ((hash_pos << 16) | chain_pos) + 2;
  95         }
  96         if (!(dir_bh = affs_bread(inode->i_dev,inode->i_ino,
  97                                   AFFS_I2BSIZE(inode))))
  98                 goto readdir_done;
  99
 100         while (1) {
 101                 while (hash_pos < AFFS_I2HSIZE(inode) &&
 102                      !((struct dir_front *)dir_bh->b_data)->hashtable[hash_pos])
 103                         hash_pos++;
 104                 if (hash_pos >= AFFS_I2HSIZE(inode))
 105                         break;
 106
 107                 i = be32_to_cpu(((struct dir_front *)dir_bh->b_data)->hashtable[hash_pos]);
 108                 j = chain_pos;
 109
 110                 /* If the directory hasn't changed since the last call to readdir(),
 111                  * we can jump directly to where we left off.
 112                  */
 113                 if (filp->private_data && filp->f_version == inode->i_version) {
 114                         i = (s32)filp->private_data;
 115                         j = 0;
 116                         pr_debug("AFFS: readdir() left off=%d\n",i);
 117                 }
 118                 filp->f_version = inode->i_version;
 119                 pr_debug("AFFS: hash_pos=%d chain_pos=%d\n",hash_pos,chain_pos);
 120                 while (i) {
 121                         if (!(fh_bh = affs_bread(inode->i_dev,i,AFFS_I2BSIZE(inode)))) {
 122                                 affs_error(inode->i_sb,"readdir","Cannot read block %d",i);
 123                                 goto readdir_done;
 124                         }
 125                         ino = i;
 126                         i   = be32_to_cpu(FILE_END(fh_bh->b_data,inode)->hash_chain);
 127                         if (j == 0)
 128                                 break;
 129                         affs_brelse(fh_bh);
 130                         fh_bh = NULL;
 131                         j--;
 132                 }
 133                 if (fh_bh) {
 134                         namelen = affs_get_file_name(AFFS_I2BSIZE(inode),fh_bh->b_data,&name);
 135                         pr_debug("AFFS: readdir(): filldir(\"%.*s\",ino=%lu), i=%d\n",
 136                                  namelen,name,ino,i);
 137                         filp->private_data = (void *)ino;
 138                         if (filldir(dirent,name,namelen,filp->f_pos,ino) < 0)
 139                                 goto readdir_done;
 140                         filp->private_data = (void *)i;
 141                         affs_brelse(fh_bh);
 142                         fh_bh = NULL;
 143                         stored++;
 144                 }
 145                 if (i == 0) {
 146                         hash_pos++;
 147                         chain_pos = 0;
 148                 } else
 149                         chain_pos++;
 150                 filp->f_pos = ((hash_pos << 16) | chain_pos) + 2;
 151         }
 152
 153 readdir_done:
 154         affs_brelse(dir_bh);
 155         affs_brelse(fh_bh);
 156         pr_debug("AFFS: readdir()=%d\n",stored);
 157         return stored;
 158 }