iget: stop EXT2 from using iget() and read_inode()

Stop the EXT2 filesystem from using iget() and read_inode().  Replace
ext2_read_inode() with ext2_iget(), and call that instead of iget().
ext2_iget() then uses iget_locked() directly and returns a proper error code
instead of an inode in the event of an error.

ext2_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>
Acked-by: "Theodore Ts'o" <tytso@mit.edu>
Cc: <linux-ext4@vger.kernel.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>
diff --git a/fs/ext2/inode.c b/fs/ext2/inode.c
index 03978ec..c620068 100644
--- a/fs/ext2/inode.c
+++ b/fs/ext2/inode.c
@@ -1181,22 +1181,33 @@
 		ei->i_flags |= EXT2_DIRSYNC_FL;
 }
 
-void ext2_read_inode (struct inode * inode)
+struct inode *ext2_iget (struct super_block *sb, unsigned long ino)
 {
-	struct ext2_inode_info *ei = EXT2_I(inode);
-	ino_t ino = inode->i_ino;
+	struct ext2_inode_info *ei;
 	struct buffer_head * bh;
-	struct ext2_inode * raw_inode = ext2_get_inode(inode->i_sb, ino, &bh);
+	struct ext2_inode *raw_inode;
+	struct inode *inode;
+	long ret = -EIO;
 	int n;
 
+	inode = iget_locked(sb, ino);
+	if (!inode)
+		return ERR_PTR(-ENOMEM);
+	if (!(inode->i_state & I_NEW))
+		return inode;
+
+	ei = EXT2_I(inode);
 #ifdef CONFIG_EXT2_FS_POSIX_ACL
 	ei->i_acl = EXT2_ACL_NOT_CACHED;
 	ei->i_default_acl = EXT2_ACL_NOT_CACHED;
 #endif
 	ei->i_block_alloc_info = NULL;
 
-	if (IS_ERR(raw_inode))
+	raw_inode = ext2_get_inode(inode->i_sb, ino, &bh);
+	if (IS_ERR(raw_inode)) {
+		ret = PTR_ERR(raw_inode);
  		goto bad_inode;
+	}
 
 	inode->i_mode = le16_to_cpu(raw_inode->i_mode);
 	inode->i_uid = (uid_t)le16_to_cpu(raw_inode->i_uid_low);
@@ -1220,6 +1231,7 @@
 	if (inode->i_nlink == 0 && (inode->i_mode == 0 || ei->i_dtime)) {
 		/* this inode is deleted */
 		brelse (bh);
+		ret = -ESTALE;
 		goto bad_inode;
 	}
 	inode->i_blocks = le32_to_cpu(raw_inode->i_blocks);
@@ -1286,11 +1298,12 @@
 	}
 	brelse (bh);
 	ext2_set_inode_flags(inode);
-	return;
+	unlock_new_inode(inode);
+	return inode;
 	
 bad_inode:
-	make_bad_inode(inode);
-	return;
+	iget_failed(inode);
+	return ERR_PTR(ret);
 }
 
 static int ext2_update_inode(struct inode * inode, int do_sync)