lustre/obdfs/dir.c

   1 /*
   2  *  linux/fs/ext2/dir.c
   3  *
   4  * Copyright (C) 1992, 1993, 1994, 1995
   5  * Remy Card (card@masi.ibp.fr)
   6  * Laboratoire MASI - Institut Blaise Pascal
   7  * Universite Pierre et Marie Curie (Paris VI)
   8  *
   9  *  from
  10  *
  11  *  linux/fs/minix/dir.c
  12  *
  13  *  Copyright (C) 1991, 1992  Linus Torvalds
  14  *
  15  *  ext2 directory handling functions
  16  *
  17  *  Big-endian to little-endian byte-swapping/bitmaps by
  18  *        David S. Miller (davem@caip.rutgers.edu), 1995
  19  *
  20  *  Changes for use with Object Based Device File System
  21  *
  22  *  Copyright (C) 1999, Seagate Technology Inc.
  23  *   (author Peter J. Braam, braam@stelias.com)
  24  *
  25  */
  26
  27 #include <asm/uaccess.h>
  28
  29 #include <linux/errno.h>
  30 #include <linux/fs.h>
  31 #include <linux/fcntl.h>
  32 #include <linux/sched.h>
  33 #include <linux/stat.h>
  34 #include <linux/string.h>
  35 #include <linux/locks.h>
  36 #include <linux/quotaops.h>
  37 #include <linux/iobuf.h>
  38 #include <linux/obd_support.h>
  39 #include <linux/obdfs.h>
  40
  41 static ssize_t obdfs_dir_read (struct file * filp, char * buf,
  42                               size_t count, loff_t *ppos)
  43 {
  44         return -EISDIR;
  45 }
  46
  47 static int obdfs_readdir(struct file *, void *, filldir_t);
  48
  49 struct file_operations obdfs_dir_operations = {
  50         read: obdfs_dir_read,
  51         readdir: obdfs_readdir
  52 };
  53
  54 struct inode_operations obdfs_dir_inode_operations = {
  55         create: obdfs_create,
  56         lookup: obdfs_lookup,
  57         link: obdfs_link,
  58         unlink: obdfs_unlink,
  59         symlink: obdfs_symlink,
  60         mkdir: obdfs_mkdir,
  61         rmdir: obdfs_rmdir,
  62         mknod: obdfs_mknod,
  63         rename: obdfs_rename,
  64         truncate: obdfs_truncate
  65 };
  66
  67 int obdfs_check_dir_entry (const char * function, struct inode * dir,
  68                           struct ext2_dir_entry_2 * de,
  69                           struct page * page,
  70                           unsigned long offset)
  71 {
  72         const char * error_msg = NULL;
  73         return 1;
  74
  75         ENTRY;
  76         if ( !de ) {
  77                 error_msg = "null de passed";
  78                 return 1;
  79         }
  80
  81         if (le16_to_cpu(de->rec_len) < EXT2_DIR_REC_LEN(1))
  82                 error_msg = "rec_len is smaller than minimal";
  83         else if (le16_to_cpu(de->rec_len) % 4 != 0)
  84                 error_msg = "rec_len % 4 != 0";
  85         else if (le16_to_cpu(de->rec_len) < EXT2_DIR_REC_LEN(de->name_len))
  86                 error_msg = "rec_len is too small for name_len";
  87         else if (dir && ((char *) de - (char *)page_address(page)) + le16_to_cpu(de->rec_len) >
  88                  dir->i_sb->s_blocksize)
  89                 error_msg = "directory entry across blocks";
  90 #if 0 /* this one doesn't yet work for OBDFS */
  91         else
  92
  93 if (dir && le32_to_cpu(de->inode) > le32_to_cpu(dir->i_sb->u.ext2_sb.s_es->s_inodes_count))
  94                 error_msg = "inode out of bounds";
  95 #endif
  96         if (error_msg != NULL)
  97                 ext2_error (dir->i_sb, function, "bad entry in directory #%lu: %s - "
  98                             "offset=%lu, inode=%lu, rec_len=%d, name_len=%d",
  99                             dir->i_ino, error_msg, offset,
 100                             (unsigned long) le32_to_cpu(de->inode),
 101                             le16_to_cpu(de->rec_len), de->name_len);
 102         EXIT;
 103         return error_msg == NULL ? 1 : 0;
 104 }
 105
 106
 107 static int obdfs_readdir(struct file * filp, void * dirent, filldir_t filldir)
 108 {
 109         int error = 0;
 110         unsigned long offset;
 111         int stored;
 112         struct ext2_dir_entry_2 * de;
 113         struct super_block * sb;
 114         struct page *page;
 115         struct inode *inode = filp->f_dentry->d_inode;
 116
 117         ENTRY;
 118
 119         sb = inode->i_sb;
 120
 121         stored = 0;
 122         offset = filp->f_pos & (PAGE_SIZE - 1);
 123
 124         OIDEBUG(inode);
 125         while (!error && !stored && filp->f_pos < inode->i_size) {
 126                 page = obdfs_getpage(inode, filp->f_pos, 0, LOCKED);
 127                 /* PDEBUG(page, "readdir"); */
 128                 if (!page) {
 129                         ext2_error (sb, "ext2_readdir",
 130                                     "directory #%lu contains a hole at offset %lu",
 131                                     inode->i_ino, (unsigned long)filp->f_pos);
 132                         filp->f_pos += PAGE_SIZE - offset;
 133                         continue;
 134                 }
 135
 136 #if 0
 137                 /* XXX need to do read ahead and support stuff below */
 138 revalidate:
 139                 /* If the dir block has changed since the last call to
 140                  * readdir(2), then we might be pointing to an invalid
 141                  * dirent right now.  Scan from the start of the block
 142                  * to make sure. */
 143                 if (filp->f_version != inode->i_version) {
 144                         for (i = 0; i < sb->s_blocksize && i < offset; ) {
 145                                 de = (struct ext2_dir_entry_2 *)
 146                                         (bh->b_data + i);
 147                                 /* It's too expensive to do a full
 148                                  * dirent test each time round this
 149                                  * loop, but we do have to test at
 150                                  * least that it is non-zero.  A
 151                                  * failure will be detected in the
 152                                  * dirent test below. */
 153                                 if (le16_to_cpu(de->rec_len) < EXT2_DIR_REC_LEN(1))
 154                                         break;
 155                                 i += le16_to_cpu(de->rec_len);
 156                         }
 157                         offset = i;
 158                         filp->f_pos = (filp->f_pos & ~(sb->s_blocksize - 1))
 159                                 | offset;
 160                         filp->f_version = inode->i_version;
 161                 }
 162 #endif
 163                 while (!error && filp->f_pos < inode->i_size
 164                        && offset < PAGE_SIZE) {
 165                         de = (struct ext2_dir_entry_2 *) ((char *)page_address(page) + offset);
 166 #if 0
 167                         if (!obdfs_check_dir_entry ("ext2_readdir", inode, de,
 168                                                    bh, offset)) {
 169                                 /* On error, skip the f_pos to the
 170                                    next block. */
 171                                 filp->f_pos = (filp->f_pos & (sb->s_blocksize - 1))
 172                                               + sb->s_blocksize;
 173                                 brelse (bh);
 174                                 return stored;
 175                         }
 176 #endif
 177                         offset += le16_to_cpu(de->rec_len);
 178                         if (le32_to_cpu(de->inode)) {
 179                                 unsigned char d_type = DT_UNKNOWN;
 180                                 /* We might block in the next section
 181                                  * if the data destination is
 182                                  * currently swapped out.  So, use a
 183                                  * version stamp to detect whether or
 184                                  * not the directory has been modified
 185                                  * during the copy operation.
 186                                  */
 187                                 /* XXX
 188                                 unsigned long version = inode->i_version;
 189                                  */
 190                                 error = filldir
 191                                         (dirent, de->name, de->name_len,
 192                                          filp->f_pos, le32_to_cpu(de->inode),
 193                                          d_type);
 194                                 if (error)
 195                                         break;
 196 #if 0
 197                                 if (version != inode->i_version)
 198                                         goto revalidate;
 199 #endif
 200                                 stored ++;
 201                         }
 202                         filp->f_pos += le16_to_cpu(de->rec_len);
 203                 }
 204                 offset = 0;
 205                 obd_unlock_page(page);
 206                 page_cache_release(page);
 207         }
 208         UPDATE_ATIME(inode);
 209         EXIT;
 210         return 0;
 211 }