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>
diff --git a/include/linux/qnx4_fs.h b/include/linux/qnx4_fs.h
index 19bc9b8..34a196e 100644
--- a/include/linux/qnx4_fs.h
+++ b/include/linux/qnx4_fs.h
@@ -110,6 +110,7 @@
 	struct inode vfs_inode;
 };
 
+extern struct inode *qnx4_iget(struct super_block *, unsigned long);
 extern struct dentry *qnx4_lookup(struct inode *dir, struct dentry *dentry, struct nameidata *nd);
 extern unsigned long qnx4_count_free_blocks(struct super_block *sb);
 extern unsigned long qnx4_block_map(struct inode *inode, long iblock);