ocfs2: rollback alloc_dinode counts when ocfs2_block_group_set_bits() failed

After updating alloc_dinode counts in ocfs2_alloc_dinode_update_counts(),
if ocfs2_alloc_dinode_update_bitmap() failed, there is a rare case that
some space may be lost.

So, roll back alloc_dinode counts when ocfs2_block_group_set_bits()
failed.

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Younger Liu <younger.liucn@gmail.com>
Reviewed-by: Mark Fasheh <mfasheh@suse.de>
Cc: Joel Becker <jlbec@evilplan.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/fs/ocfs2/move_extents.c b/fs/ocfs2/move_extents.c
index 3ca9395..599eb4c 100644
--- a/fs/ocfs2/move_extents.c
+++ b/fs/ocfs2/move_extents.c
@@ -691,8 +691,11 @@
 
 	ret = ocfs2_block_group_set_bits(handle, gb_inode, gd, gd_bh,
 					 goal_bit, len);
-	if (ret)
+	if (ret) {
+		ocfs2_rollback_alloc_dinode_counts(gb_inode, gb_bh, len,
+					       le16_to_cpu(gd->bg_chain));
 		mlog_errno(ret);
+	}
 
 	/*
 	 * Here we should write the new page out first if we are