From ace9429bb58fd418f0c81d4c2835699bddf6bde6 Mon Sep 17 00:00:00 2001
From: Daniel Baumann <daniel.baumann@progress-linux.org>
Date: Thu, 11 Apr 2024 10:27:49 +0200
Subject: Adding upstream version 6.6.15.

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
---
 fs/qnx4/namei.c | 122 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 122 insertions(+)
 create mode 100644 fs/qnx4/namei.c

(limited to 'fs/qnx4/namei.c')

diff --git a/fs/qnx4/namei.c b/fs/qnx4/namei.c
new file mode 100644
index 0000000000..8d72221735
--- /dev/null
+++ b/fs/qnx4/namei.c
@@ -0,0 +1,122 @@
+// SPDX-License-Identifier: GPL-2.0
+/* 
+ * 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;
+	}
+	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;
+	bh = NULL;
+	block = offset = blkofs = 0;
+	while (blkofs * QNX4_BLOCK_SIZE + offset < dir->i_size) {
+		if (!bh) {
+			block = qnx4_block_map(dir, blkofs);
+			if (block)
+				bh = sb_bread(dir->i_sb, block);
+			if (!bh) {
+				blkofs++;
+				continue;
+			}
+		}
+		*res_dir = (struct qnx4_inode_entry *) (bh->b_data + offset);
+		if (qnx4_match(len, name, bh, &offset)) {
+			*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, unsigned int flags)
+{
+	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)));
+out:
+	return d_splice_alias(foundinode, dentry);
+}
-- 
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