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-rw-r--r--fs/qnx4/namei.c122
1 files changed, 122 insertions, 0 deletions
diff --git a/fs/qnx4/namei.c b/fs/qnx4/namei.c
new file mode 100644
index 000000000..8d7222173
--- /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);
+}