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, 17 insertions, 2 deletions

diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index c7d8fb0dbff6..deb6e3d07281 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -1496,6 +1496,14 @@ struct btrfs_root *btrfs_read_fs_root_no_radix(struct btrfs_root *tree_root,
         blocksize = btrfs_level_size(root, btrfs_root_level(&root->root_item));
         root->node = read_tree_block(root, btrfs_root_bytenr(&root->root_item),
                                      blocksize, generation);
+        if (!root->node || !extent_buffer_uptodate(root->node)) {
+                ret = (!root->node) ? -ENOMEM : -EIO;
+
+                free_extent_buffer(root->node);
+                kfree(root);
+                return ERR_PTR(ret);
+        }
+
         root->commit_root = btrfs_root_node(root);
         BUG_ON(!root->node); /* -ENOMEM */
 out:
@@ -2515,8 +2523,8 @@ int open_ctree(struct super_block *sb,
         chunk_root->node = read_tree_block(chunk_root,
                                            btrfs_super_chunk_root(disk_super),
                                            blocksize, generation);
-        BUG_ON(!chunk_root->node); /* -ENOMEM */
-        if (!test_bit(EXTENT_BUFFER_UPTODATE, &chunk_root->node->bflags)) {
+        if (!chunk_root->node ||
+            !test_bit(EXTENT_BUFFER_UPTODATE, &chunk_root->node->bflags)) {
                 printk(KERN_WARNING "btrfs: failed to read chunk root on %s\n",
                        sb->s_id);
                 goto fail_tree_roots;
@@ -2701,6 +2709,13 @@ retry_root_backup:
                 log_tree_root->node = read_tree_block(tree_root, bytenr,
                                                       blocksize,
                                                       generation + 1);
+                if (!log_tree_root->node ||
+                    !extent_buffer_uptodate(log_tree_root->node)) {
+                        printk(KERN_ERR "btrfs: failed to read log tree\n");
+                        free_extent_buffer(log_tree_root->node);
+                        kfree(log_tree_root);
+                        goto fail_trans_kthread;
+                }
                 /* returns with log_tree_root freed on success */
                 ret = btrfs_recover_log_trees(log_tree_root);
                 if (ret) {