Add the rt linux 4.1.3-rt3 as base

[kvmfornfv.git] / kernel / fs / qnx4 / namei.c

diff --git a/kernel/fs/qnx4/namei.c b/kernel/fs/qnx4/namei.c
new file mode 100644 (file)
index 0000000..e62c818
--- /dev/null
+++ b/kernel/fs/qnx4/namei.c
@@ -0,0 +1,125 @@
+/* 
+ * 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)));
+               return ERR_CAST(foundinode);
+       }
+out:
+       d_add(dentry, foundinode);
+
+       return NULL;
+}