iget: stop JFFS2 from using iget() and read_inode()

Stop the JFFS2 filesystem from using iget() and read_inode().  Replace
jffs2_read_inode() with jffs2_iget(), and call that instead of iget().
jffs2_iget() then uses iget_locked() directly and returns a proper error code
instead of an inode in the event of an error.

jffs2_do_fill_super() returns any error incurred when getting the root inode
instead of EINVAL.

Signed-off-by: David Howells <dhowells@redhat.com>
Cc: David Woodhouse <dwmw2@infradead.org>
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/jffs2/dir.c

@@ -101,10 +101,10 @@ static struct dentry *jffs2_lookup(struct inode *dir_i, struct dentry *target,
 		ino = fd->ino;
 	up(&dir_f->sem);
 	if (ino) {
-		inode = iget(dir_i->i_sb, ino);
-		if (!inode) {
+		inode = jffs2_iget(dir_i->i_sb, ino);
+		if (IS_ERR(inode)) {
 			printk(KERN_WARNING "iget() failed for ino #%u\n", ino);
-			return (ERR_PTR(-EIO));
+			return ERR_CAST(inode);
 		}
 	}