iget: stop QNX4 from using iget() and read_inode()

Stop the QNX4 filesystem from using iget() and read_inode().  Replace
qnx4_read_inode() with qnx4_iget(), and call that instead of iget().
qnx4_iget() then uses iget_locked() directly and returns a proper error code
instead of an inode in the event of an error.

qnx4_fill_super() returns any error incurred when getting the root inode
instead of EINVAL.

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: David Howells <dhowells@redhat.com>
Cc: Anders Larsen <al@alarsen.net>
Acked-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

fs/qnx4/namei.c

@@ -128,10 +128,12 @@ struct dentry * qnx4_lookup(struct inode *dir, struct dentry *dentry, struct nam
 	}
 	brelse(bh);
 
-	if ((foundinode = iget(dir->i_sb, ino)) == NULL) {
+	foundinode = qnx4_iget(dir->i_sb, ino);
+	if (IS_ERR(foundinode)) {
 		unlock_kernel();
-		QNX4DEBUG(("qnx4: lookup->iget -> NULL\n"));
-		return ERR_PTR(-EACCES);
+		QNX4DEBUG(("qnx4: lookup->iget -> error %ld\n",
+			   PTR_ERR(foundinode)));
+		return ERR_CAST(foundinode);
 	}
 out:
 	unlock_kernel();