1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * QNX4 file system, Linux implementation. 4 * 5 * Version : 0.2.1 6 * 7 * Using parts of the xiafs filesystem. 8 * 9 * History : 10 * 11 * 01-06-1998 by Richard Frowijn : first release. 12 * 21-06-1998 by Frank Denis : dcache support, fixed error codes. 13 * 04-07-1998 by Frank Denis : first step for rmdir/unlink. 14 */ 15 16 #include <linux/buffer_head.h> 17 #include "qnx4.h" 18 19 20 /* 21 * check if the filename is correct. For some obscure reason, qnx writes a 22 * new file twice in the directory entry, first with all possible options at 0 23 * and for a second time the way it is, they want us not to access the qnx 24 * filesystem when whe are using linux. 25 */ 26 static int qnx4_match(int len, const char *name, 27 struct buffer_head *bh, unsigned long *offset) 28 { 29 union qnx4_directory_entry *de; 30 const char *fname; 31 int fnamelen; 32 33 if (bh == NULL) { 34 printk(KERN_WARNING "qnx4: matching unassigned buffer !\n"); 35 return 0; 36 } 37 de = (union qnx4_directory_entry *) (bh->b_data + *offset); 38 *offset += QNX4_DIR_ENTRY_SIZE; 39 40 fname = get_entry_fname(de, &fnamelen); 41 if (!fname || len != fnamelen) 42 return 0; 43 44 if (strncmp(name, fname, len) == 0) 45 return 1; 46 47 return 0; 48 } 49 50 static struct buffer_head *qnx4_find_entry(int len, struct inode *dir, 51 const char *name, struct qnx4_inode_entry **res_dir, int *ino) 52 { 53 unsigned long block, offset, blkofs; 54 struct buffer_head *bh; 55 56 *res_dir = NULL; 57 bh = NULL; 58 block = offset = blkofs = 0; 59 while (blkofs * QNX4_BLOCK_SIZE + offset < dir->i_size) { 60 if (!bh) { 61 block = qnx4_block_map(dir, blkofs); 62 if (block) 63 bh = sb_bread(dir->i_sb, block); 64 if (!bh) { 65 blkofs++; 66 continue; 67 } 68 } 69 *res_dir = (struct qnx4_inode_entry *) (bh->b_data + offset); 70 if (qnx4_match(len, name, bh, &offset)) { 71 *ino = block * QNX4_INODES_PER_BLOCK + 72 (offset / QNX4_DIR_ENTRY_SIZE) - 1; 73 return bh; 74 } 75 if (offset < bh->b_size) { 76 continue; 77 } 78 brelse(bh); 79 bh = NULL; 80 offset = 0; 81 blkofs++; 82 } 83 brelse(bh); 84 *res_dir = NULL; 85 return NULL; 86 } 87 88 struct dentry * qnx4_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags) 89 { 90 int ino; 91 struct qnx4_inode_entry *de; 92 struct qnx4_link_info *lnk; 93 struct buffer_head *bh; 94 const char *name = dentry->d_name.name; 95 int len = dentry->d_name.len; 96 struct inode *foundinode = NULL; 97 98 if (!(bh = qnx4_find_entry(len, dir, name, &de, &ino))) 99 goto out; 100 /* The entry is linked, let's get the real info */ 101 if ((de->di_status & QNX4_FILE_LINK) == QNX4_FILE_LINK) { 102 lnk = (struct qnx4_link_info *) de; 103 ino = (le32_to_cpu(lnk->dl_inode_blk) - 1) * 104 QNX4_INODES_PER_BLOCK + 105 lnk->dl_inode_ndx; 106 } 107 brelse(bh); 108 109 foundinode = qnx4_iget(dir->i_sb, ino); 110 if (IS_ERR(foundinode)) 111 QNX4DEBUG((KERN_ERR "qnx4: lookup->iget -> error %ld\n", 112 PTR_ERR(foundinode))); 113 out: 114 return d_splice_alias(foundinode, dentry); 115 } 116