| /* |
| * QNX4 file system, Linux implementation. |
| * |
| * Version : 0.2.1 |
| * |
| * Using parts of the xiafs filesystem. |
| * |
| * History : |
| * |
| * 01-06-1998 by Richard Frowijn : first release. |
| * 21-06-1998 by Frank Denis : dcache support, fixed error codes. |
| * 04-07-1998 by Frank Denis : first step for rmdir/unlink. |
| */ |
| |
| #include <linux/buffer_head.h> |
| #include "qnx4.h" |
| |
| |
| /* |
| * check if the filename is correct. For some obscure reason, qnx writes a |
| * new file twice in the directory entry, first with all possible options at 0 |
| * and for a second time the way it is, they want us not to access the qnx |
| * filesystem when whe are using linux. |
| */ |
| static int qnx4_match(int len, const char *name, |
| struct buffer_head *bh, unsigned long *offset) |
| { |
| struct qnx4_inode_entry *de; |
| int namelen, thislen; |
| |
| if (bh == NULL) { |
| printk(KERN_WARNING "qnx4: matching unassigned buffer !\n"); |
| return 0; |
| } |
| de = (struct qnx4_inode_entry *) (bh->b_data + *offset); |
| *offset += QNX4_DIR_ENTRY_SIZE; |
| if ((de->di_status & QNX4_FILE_LINK) != 0) { |
| namelen = QNX4_NAME_MAX; |
| } else { |
| namelen = QNX4_SHORT_NAME_MAX; |
| } |
| /* "" means "." ---> so paths like "/usr/lib//libc.a" work */ |
| if (!len && (de->di_fname[0] == '.') && (de->di_fname[1] == '\0')) { |
| return 1; |
| } |
| thislen = strlen( de->di_fname ); |
| if ( thislen > namelen ) |
| thislen = namelen; |
| if (len != thislen) { |
| return 0; |
| } |
| if (strncmp(name, de->di_fname, len) == 0) { |
| if ((de->di_status & (QNX4_FILE_USED|QNX4_FILE_LINK)) != 0) { |
| return 1; |
| } |
| } |
| return 0; |
| } |
| |
| static struct buffer_head *qnx4_find_entry(int len, struct inode *dir, |
| const char *name, struct qnx4_inode_entry **res_dir, int *ino) |
| { |
| unsigned long block, offset, blkofs; |
| struct buffer_head *bh; |
| |
| *res_dir = NULL; |
| if (!dir->i_sb) { |
| printk(KERN_WARNING "qnx4: no superblock on dir.\n"); |
| return NULL; |
| } |
| bh = NULL; |
| block = offset = blkofs = 0; |
| while (blkofs * QNX4_BLOCK_SIZE + offset < dir->i_size) { |
| if (!bh) { |
| bh = qnx4_bread(dir, blkofs, 0); |
| if (!bh) { |
| blkofs++; |
| continue; |
| } |
| } |
| *res_dir = (struct qnx4_inode_entry *) (bh->b_data + offset); |
| if (qnx4_match(len, name, bh, &offset)) { |
| block = qnx4_block_map( dir, blkofs ); |
| *ino = block * QNX4_INODES_PER_BLOCK + |
| (offset / QNX4_DIR_ENTRY_SIZE) - 1; |
| return bh; |
| } |
| if (offset < bh->b_size) { |
| continue; |
| } |
| brelse(bh); |
| bh = NULL; |
| offset = 0; |
| blkofs++; |
| } |
| brelse(bh); |
| *res_dir = NULL; |
| return NULL; |
| } |
| |
| struct dentry * qnx4_lookup(struct inode *dir, struct dentry *dentry, struct nameidata *nd) |
| { |
| int ino; |
| struct qnx4_inode_entry *de; |
| struct qnx4_link_info *lnk; |
| struct buffer_head *bh; |
| const char *name = dentry->d_name.name; |
| int len = dentry->d_name.len; |
| struct inode *foundinode = NULL; |
| |
| if (!(bh = qnx4_find_entry(len, dir, name, &de, &ino))) |
| goto out; |
| /* The entry is linked, let's get the real info */ |
| if ((de->di_status & QNX4_FILE_LINK) == QNX4_FILE_LINK) { |
| lnk = (struct qnx4_link_info *) de; |
| ino = (le32_to_cpu(lnk->dl_inode_blk) - 1) * |
| QNX4_INODES_PER_BLOCK + |
| lnk->dl_inode_ndx; |
| } |
| brelse(bh); |
| |
| foundinode = qnx4_iget(dir->i_sb, ino); |
| if (IS_ERR(foundinode)) { |
| QNX4DEBUG((KERN_ERR "qnx4: lookup->iget -> error %ld\n", |
| PTR_ERR(foundinode))); |
| return ERR_CAST(foundinode); |
| } |
| out: |
| d_add(dentry, foundinode); |
| |
| return NULL; |
| } |