fs/qnx4/namei.c

   1 /*
   2  * QNX4 file system, Linux implementation.
   3  *
   4  * Version : 0.2.1
   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/time.h>
  17 #include <linux/fs.h>
  18 #include <linux/qnx4_fs.h>
  19 #include <linux/kernel.h>
  20 #include <linux/string.h>
  21 #include <linux/stat.h>
  22 #include <linux/fcntl.h>
  23 #include <linux/errno.h>
  24 #include <linux/smp_lock.h>
  25 #include <linux/buffer_head.h>
  26
  27
  28 /*
  29  * check if the filename is correct. For some obscure reason, qnx writes a
  30  * new file twice in the directory entry, first with all possible options at 0
  31  * and for a second time the way it is, they want us not to access the qnx
  32  * filesystem when whe are using linux.
  33  */
  34 static int qnx4_match(int len, const char *name,
  35                       struct buffer_head *bh, unsigned long *offset)
  36 {
  37         struct qnx4_inode_entry *de;
  38         int namelen, thislen;
  39
  40         if (bh == NULL) {
  41                 printk("qnx4: matching unassigned buffer !\n");
  42                 return 0;
  43         }
  44         de = (struct qnx4_inode_entry *) (bh->b_data + *offset);
  45         *offset += QNX4_DIR_ENTRY_SIZE;
  46         if ((de->di_status & QNX4_FILE_LINK) != 0) {
  47                 namelen = QNX4_NAME_MAX;
  48         } else {
  49                 namelen = QNX4_SHORT_NAME_MAX;
  50         }
  51         /* "" means "." ---> so paths like "/usr/lib//libc.a" work */
  52         if (!len && (de->di_fname[0] == '.') && (de->di_fname[1] == '\0')) {
  53                 return 1;
  54         }
  55         thislen = strlen( de->di_fname );
  56         if ( thislen > namelen )
  57                 thislen = namelen;
  58         if (len != thislen) {
  59                 return 0;
  60         }
  61         if (strncmp(name, de->di_fname, len) == 0) {
  62                 if ((de->di_status & (QNX4_FILE_USED|QNX4_FILE_LINK)) != 0) {
  63                         return 1;
  64                 }
  65         }
  66         return 0;
  67 }
  68
  69 static struct buffer_head *qnx4_find_entry(int len, struct inode *dir,
  70            const char *name, struct qnx4_inode_entry **res_dir, int *ino)
  71 {
  72         unsigned long block, offset, blkofs;
  73         struct buffer_head *bh;
  74
  75         *res_dir = NULL;
  76         if (!dir->i_sb) {
  77                 printk("qnx4: no superblock on dir.\n");
  78                 return NULL;
  79         }
  80         bh = NULL;
  81         block = offset = blkofs = 0;
  82         while (blkofs * QNX4_BLOCK_SIZE + offset < dir->i_size) {
  83                 if (!bh) {
  84                         bh = qnx4_bread(dir, blkofs, 0);
  85                         if (!bh) {
  86                                 blkofs++;
  87                                 continue;
  88                         }
  89                 }
  90                 *res_dir = (struct qnx4_inode_entry *) (bh->b_data + offset);
  91                 if (qnx4_match(len, name, bh, &offset)) {
  92                         block = qnx4_block_map( dir, blkofs );
  93                         *ino = block * QNX4_INODES_PER_BLOCK +
  94                             (offset / QNX4_DIR_ENTRY_SIZE) - 1;
  95                         return bh;
  96                 }
  97                 if (offset < bh->b_size) {
  98                         continue;
  99                 }
 100                 brelse(bh);
 101                 bh = NULL;
 102                 offset = 0;
 103                 blkofs++;
 104         }
 105         brelse(bh);
 106         *res_dir = NULL;
 107         return NULL;
 108 }
 109
 110 struct dentry * qnx4_lookup(struct inode *dir, struct dentry *dentry, struct nameidata *nd)
 111 {
 112         int ino;
 113         struct qnx4_inode_entry *de;
 114         struct qnx4_link_info *lnk;
 115         struct buffer_head *bh;
 116         const char *name = dentry->d_name.name;
 117         int len = dentry->d_name.len;
 118         struct inode *foundinode = NULL;
 119
 120         lock_kernel();
 121         if (!(bh = qnx4_find_entry(len, dir, name, &de, &ino)))
 122                 goto out;
 123         /* The entry is linked, let's get the real info */
 124         if ((de->di_status & QNX4_FILE_LINK) == QNX4_FILE_LINK) {
 125                 lnk = (struct qnx4_link_info *) de;
 126                 ino = (le32_to_cpu(lnk->dl_inode_blk) - 1) *
 127                     QNX4_INODES_PER_BLOCK +
 128                     lnk->dl_inode_ndx;
 129         }
 130         brelse(bh);
 131
 132         if ((foundinode = iget(dir->i_sb, ino)) == NULL) {
 133                 unlock_kernel();
 134                 QNX4DEBUG(("qnx4: lookup->iget -> NULL\n"));
 135                 return ERR_PTR(-EACCES);
 136         }
 137 out:
 138         unlock_kernel();
 139         d_add(dentry, foundinode);
 140
 141         return NULL;
 142 }
 143
 144 #ifdef CONFIG_QNX4FS_RW
 145 int qnx4_create(struct inode *dir, struct dentry *dentry, int mode,
 146                 struct nameidata *nd)
 147 {
 148         QNX4DEBUG(("qnx4: qnx4_create\n"));
 149         if (dir == NULL) {
 150                 return -ENOENT;
 151         }
 152         return -ENOSPC;
 153 }
 154
 155 int qnx4_rmdir(struct inode *dir, struct dentry *dentry)
 156 {
 157         struct buffer_head *bh;
 158         struct qnx4_inode_entry *de;
 159         struct inode *inode;
 160         int retval;
 161         int ino;
 162
 163         QNX4DEBUG(("qnx4: qnx4_rmdir [%s]\n", dentry->d_name.name));
 164         lock_kernel();
 165         bh = qnx4_find_entry(dentry->d_name.len, dir, dentry->d_name.name,
 166                              &de, &ino);
 167         if (bh == NULL) {
 168                 unlock_kernel();
 169                 return -ENOENT;
 170         }
 171         inode = dentry->d_inode;
 172         if (inode->i_ino != ino) {
 173                 retval = -EIO;
 174                 goto end_rmdir;
 175         }
 176 #if 0
 177         if (!empty_dir(inode)) {
 178                 retval = -ENOTEMPTY;
 179                 goto end_rmdir;
 180         }
 181 #endif
 182         if (inode->i_nlink != 2) {
 183                 QNX4DEBUG(("empty directory has nlink!=2 (%d)\n", inode->i_nlink));
 184         }
 185         QNX4DEBUG(("qnx4: deleting directory\n"));
 186         de->di_status = 0;
 187         memset(de->di_fname, 0, sizeof de->di_fname);
 188         de->di_mode = 0;
 189         mark_buffer_dirty(bh);
 190         inode->i_nlink = 0;
 191         mark_inode_dirty(inode);
 192         inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME_SEC;
 193         dir->i_nlink--;
 194         mark_inode_dirty(dir);
 195         retval = 0;
 196
 197       end_rmdir:
 198         brelse(bh);
 199
 200         unlock_kernel();
 201         return retval;
 202 }
 203
 204 int qnx4_unlink(struct inode *dir, struct dentry *dentry)
 205 {
 206         struct buffer_head *bh;
 207         struct qnx4_inode_entry *de;
 208         struct inode *inode;
 209         int retval;
 210         int ino;
 211
 212         QNX4DEBUG(("qnx4: qnx4_unlink [%s]\n", dentry->d_name.name));
 213         lock_kernel();
 214         bh = qnx4_find_entry(dentry->d_name.len, dir, dentry->d_name.name,
 215                              &de, &ino);
 216         if (bh == NULL) {
 217                 unlock_kernel();
 218                 return -ENOENT;
 219         }
 220         inode = dentry->d_inode;
 221         if (inode->i_ino != ino) {
 222                 retval = -EIO;
 223                 goto end_unlink;
 224         }
 225         retval = -EPERM;
 226         if (!inode->i_nlink) {
 227                 QNX4DEBUG(("Deleting nonexistent file (%s:%lu), %d\n",
 228                            inode->i_sb->s_id,
 229                            inode->i_ino, inode->i_nlink));
 230                 inode->i_nlink = 1;
 231         }
 232         de->di_status = 0;
 233         memset(de->di_fname, 0, sizeof de->di_fname);
 234         de->di_mode = 0;
 235         mark_buffer_dirty(bh);
 236         dir->i_ctime = dir->i_mtime = CURRENT_TIME_SEC;
 237         mark_inode_dirty(dir);
 238         inode->i_nlink--;
 239         inode->i_ctime = dir->i_ctime;
 240         mark_inode_dirty(inode);
 241         retval = 0;
 242
 243 end_unlink:
 244         unlock_kernel();
 245         brelse(bh);
 246
 247         return retval;
 248 }
 249 #endif