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1// SPDX-License-Identifier: GPL-2.02/* 3 * QNX4 file system, Linux implementation.4 * 5 * Version : 0.2.16 * 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 a22 * new file twice in the directory entry, first with all possible options at 023 * and for a second time the way it is, they want us not to access the qnx24 * filesystem when whe are using linux.25 */26static 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 50static 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 88struct 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)));113out:114 return d_splice_alias(foundinode, dentry);115}116