i386/linux-2.3.21/fs/qnx4/namei.c

   1 /*
   2  * QNX4 file system, Linux implementation.
   3  *
   4  * Version : 0.1
   5  *
   6  * Using parts of the xiafs filesystem.
   7  *
   8  * History :
   9  *
  10  * 01-06-1998 by Richard Frowijn : first release.
  11  * 21-06-1998 by Frank Denis : dcache support, fixed error codes.
  12  * 04-07-1998 by Frank Denis : first step for rmdir/unlink.
  13  */
  14
  15 #include <linux/config.h>
  16 #include <linux/sched.h>
  17 #include <linux/qnx4_fs.h>
  18 #include <linux/kernel.h>
  19 #include <linux/string.h>
  20 #include <linux/stat.h>
  21 #include <linux/fcntl.h>
  22 #include <linux/errno.h>
  23
  24 #include <asm/segment.h>
  25
  26 /*
  27  * check if the filename is correct. For some obscure reason, qnx writes a
  28  * new file twice in the directory entry, first with all possible options at 0
  29  * and for a second time the way it is, they want us not to access the qnx
  30  * filesystem when whe are using linux.
  31  */
  32 static int qnx4_match(int len, const char *name,
  33                       struct buffer_head *bh, unsigned long *offset)
  34 {
  35         struct qnx4_inode_entry *de;
  36         int namelen;
  37
  38         if (bh == NULL) {
  39                 printk("qnx4: matching unassigned buffer !\n");
  40                 return 0;
  41         }
  42         de = (struct qnx4_inode_entry *) (bh->b_data + *offset);
  43         *offset += QNX4_DIR_ENTRY_SIZE;
  44         if ((de->di_status & 0x08) == 0x08) {
  45                 namelen = QNX4_NAME_MAX;
  46         } else {
  47                 namelen = _SHORT_NAME_MAX;
  48         }
  49         /* "" means "." ---> so paths like "/usr/lib//libc.a" work */
  50         if (!len && (de->di_fname[0] == '.') && (de->di_fname[1] == '\0')) {
  51                 return 1;
  52         }
  53         if (len != strlen(de->di_fname)) {
  54                 return 0;
  55         }
  56         if (strncmp(name, de->di_fname, len) == 0) {
  57                 if ((de->di_mode) || (de->di_status == QNX4_FILE_LINK)) {
  58                         if (de->di_status) {
  59                                 return 1;
  60                         }
  61                 }
  62         }
  63         return 0;
  64 }
  65
  66 static struct buffer_head *qnx4_find_entry(int len, struct inode *dir,
  67            const char *name, struct qnx4_inode_entry **res_dir, int *ino)
  68 {
  69         unsigned long block, offset, blkofs;
  70         struct buffer_head *bh;
  71
  72         *res_dir = NULL;
  73         if (!dir->i_sb) {
  74                 printk("qnx4: no superblock on dir.\n");
  75                 return NULL;
  76         }
  77         bh = NULL;
  78         blkofs = dir->u.qnx4_i.i_first_xtnt.xtnt_blk - 1;
  79         offset = block = 0;
  80         while (block * QNX4_BLOCK_SIZE + offset < dir->i_size) {
  81                 if (!bh) {
  82                         bh = qnx4_bread(dir, block + blkofs, 0);
  83                         if (!bh) {
  84                                 block++;
  85                                 continue;
  86                         }
  87                 }
  88                 *res_dir = (struct qnx4_inode_entry *) (bh->b_data + offset);
  89                 if (qnx4_match(len, name, bh, &offset)) {
  90                         *ino = (block + blkofs) * QNX4_INODES_PER_BLOCK +
  91                             (offset / QNX4_DIR_ENTRY_SIZE) - 1;
  92                         return bh;
  93                 }
  94                 if (offset < bh->b_size) {
  95                         continue;
  96                 }
  97                 brelse(bh);
  98                 bh = NULL;
  99                 offset = 0;
 100                 block++;
 101         }
 102         brelse(bh);
 103         *res_dir = NULL;
 104         return NULL;
 105 }
 106
 107 struct dentry * qnx4_lookup(struct inode *dir, struct dentry *dentry)
 108 {
 109         int ino;
 110         struct qnx4_inode_entry *de;
 111         struct qnx4_link_info *lnk;
 112         struct buffer_head *bh;
 113         const char *name = dentry->d_name.name;
 114         int len = dentry->d_name.len;
 115         struct inode *foundinode = NULL;
 116
 117         if (!(bh = qnx4_find_entry(len, dir, name, &de, &ino)))
 118                 goto out;
 119         /* The entry is linked, let's get the real info */
 120         if ((de->di_status & QNX4_FILE_LINK) == QNX4_FILE_LINK) {
 121                 lnk = (struct qnx4_link_info *) de;
 122                 ino = (lnk->dl_inode_blk - 1) * QNX4_INODES_PER_BLOCK +
 123                     lnk->dl_inode_ndx;
 124         }
 125         brelse(bh);
 126
 127         if ((foundinode = iget(dir->i_sb, ino)) == NULL) {
 128                 QNX4DEBUG(("qnx4: lookup->iget -> NULL\n"));
 129                 return ERR_PTR(-EACCES);
 130         }
 131 out:
 132         d_add(dentry, foundinode);
 133
 134         return NULL;
 135 }
 136
 137 #ifdef CONFIG_QNX4FS_RW
 138 int qnx4_create(struct inode *dir, struct dentry *dentry, int mode)
 139 {
 140         QNX4DEBUG(("qnx4: qnx4_create\n"));
 141         if (dir == NULL) {
 142                 return -ENOENT;
 143         }
 144         return -ENOSPC;
 145 }
 146
 147 int qnx4_rmdir(struct inode *dir, struct dentry *dentry)
 148 {
 149         struct buffer_head *bh;
 150         struct qnx4_inode_entry *de;
 151         struct inode *inode;
 152         int retval;
 153         int ino;
 154
 155         QNX4DEBUG(("qnx4: qnx4_rmdir [%s]\n", dentry->d_name.name));
 156         bh = qnx4_find_entry(dentry->d_name.len, dir, dentry->d_name.name,
 157                              &de, &ino);
 158         if (bh == NULL) {
 159                 return -ENOENT;
 160         }
 161         inode = dentry->d_inode;
 162         if (inode->i_ino != ino) {
 163                 retval = -EIO;
 164                 goto end_rmdir;
 165         }
 166 #if 0
 167         if (!empty_dir(inode)) {
 168                 retval = -ENOTEMPTY;
 169                 goto end_rmdir;
 170         }
 171 #endif
 172         if (!list_empty(&dentry->d_hash)) {
 173                 retval = -EBUSY;
 174                 goto end_rmdir;
 175         }
 176         if (inode->i_nlink != 2) {
 177                 QNX4DEBUG(("empty directory has nlink!=2 (%d)\n", inode->i_nlink));
 178         }
 179         QNX4DEBUG(("qnx4: deleting directory\n"));
 180         de->di_status = 0;
 181         memset(de->di_fname, 0, sizeof de->di_fname);
 182         de->di_mode = 0;
 183         mark_buffer_dirty(bh, 1);
 184         inode->i_nlink = 0;
 185         mark_inode_dirty(inode);
 186         inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME;
 187         dir->i_nlink--;
 188         mark_inode_dirty(dir);
 189         d_delete(dentry);
 190         retval = 0;
 191
 192       end_rmdir:
 193         brelse(bh);
 194
 195         return retval;
 196 }
 197
 198 int qnx4_unlink(struct inode *dir, struct dentry *dentry)
 199 {
 200         struct buffer_head *bh;
 201         struct qnx4_inode_entry *de;
 202         struct inode *inode;
 203         int retval;
 204         int ino;
 205
 206         QNX4DEBUG(("qnx4: qnx4_unlink [%s]\n", dentry->d_name.name));
 207         bh = qnx4_find_entry(dentry->d_name.len, dir, dentry->d_name.name,
 208                              &de, &ino);
 209         if (bh == NULL) {
 210                 return -ENOENT;
 211         }
 212         inode = dentry->d_inode;
 213         if (inode->i_ino != ino) {
 214                 retval = -EIO;
 215                 goto end_unlink;
 216         }
 217         retval = -EPERM;
 218         if (!inode->i_nlink) {
 219                 QNX4DEBUG(("Deleting nonexistent file (%s:%lu), %d\n",
 220                            kdevname(inode->i_dev),
 221                            inode->i_ino, inode->i_nlink));
 222                 inode->i_nlink = 1;
 223         }
 224         de->di_status = 0;
 225         memset(de->di_fname, 0, sizeof de->di_fname);
 226         de->di_mode = 0;
 227         mark_buffer_dirty(bh, 1);
 228         dir->i_ctime = dir->i_mtime = CURRENT_TIME;
 229         mark_inode_dirty(dir);
 230         inode->i_nlink--;
 231         inode->i_ctime = dir->i_ctime;
 232         mark_inode_dirty(inode);
 233         d_delete(dentry);
 234         retval = 0;
 235
 236       end_unlink:
 237         brelse(bh);
 238
 239         return retval;
 240 }
 241 #endif