Btrfs: fix all callers of read_tree_block

We kept leaking extent buffers when mounting a broken file system and it turns
out it's because not everybody uses read_tree_block properly.  You need to check
and make sure the extent_buffer is uptodate before you use it.  This patch fixes
everybody who calls read_tree_block directly to make sure they check that it is
uptodate and free it and return an error if it is not.  With this we no longer
leak EB's when things go horribly wrong.  Thanks,

Signed-off-by: Josef Bacik <jbacik@fusionio.com>

1 files changed, 15 insertions, 3 deletions

diff --git a/fs/btrfs/relocation.c b/fs/btrfs/relocation.c
index 208154986c4c..63cdd9246c70 100644
--- a/fs/btrfs/relocation.c
+++ b/fs/btrfs/relocation.c
@@ -1771,7 +1771,11 @@ again:
 
 			eb = read_tree_block(dest, old_bytenr, blocksize,
 					     old_ptr_gen);
-			BUG_ON(!eb);
+			if (!eb || !extent_buffer_uptodate(eb)) {
+				ret = (!eb) ? -ENOMEM : -EIO;
+				free_extent_buffer(eb);
+				return ret;
+			}
 			btrfs_tree_lock(eb);
 			if (cow) {
 				ret = btrfs_cow_block(trans, dest, eb, parent,
@@ -1924,6 +1928,10 @@ int walk_down_reloc_tree(struct btrfs_root *root, struct btrfs_path *path,
 		bytenr = btrfs_node_blockptr(eb, path->slots[i]);
 		blocksize = btrfs_level_size(root, i - 1);
 		eb = read_tree_block(root, bytenr, blocksize, ptr_gen);
+		if (!eb || !extent_buffer_uptodate(eb)) {
+			free_extent_buffer(eb);
+			return -EIO;
+		}
 		BUG_ON(btrfs_header_level(eb) != i - 1);
 		path->nodes[i - 1] = eb;
 		path->slots[i - 1] = 0;
@@ -2601,7 +2609,8 @@ static int do_relocation(struct btrfs_trans_handle *trans,
 		blocksize = btrfs_level_size(root, node->level);
 		generation = btrfs_node_ptr_generation(upper->eb, slot);
 		eb = read_tree_block(root, bytenr, blocksize, generation);
-		if (!eb) {
+		if (!eb || !extent_buffer_uptodate(eb)) {
+			free_extent_buffer(eb);
 			err = -EIO;
 			goto next;
 		}
@@ -2762,7 +2771,10 @@ static int get_tree_block_key(struct reloc_control *rc,
 	BUG_ON(block->key_ready);
 	eb = read_tree_block(rc->extent_root, block->bytenr,
 			     block->key.objectid, block->key.offset);
-	BUG_ON(!eb);
+	if (!eb || !extent_buffer_uptodate(eb)) {
+		free_extent_buffer(eb);
+		return -EIO;
+	}
 	WARN_ON(btrfs_header_level(eb) != block->level);
 	if (block->level == 0)
 		btrfs_item_key_to_cpu(eb, &block->key, 0);